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1
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An Z, Jiang A, Chen J. Toward understanding the role of genomic repeat elements in neurodegenerative diseases. Neural Regen Res 2025; 20:646-659. [PMID: 38886931 PMCID: PMC11433896 DOI: 10.4103/nrr.nrr-d-23-01568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/21/2023] [Accepted: 03/02/2024] [Indexed: 06/20/2024] Open
Abstract
Neurodegenerative diseases cause great medical and economic burdens for both patients and society; however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage sequencing technology, researchers have started to notice that genomic repeat regions, previously neglected in search of disease culprits, are active contributors to multiple neurodegenerative diseases. In this review, we describe the association between repeat element variants and multiple degenerative diseases through genome-wide association studies and targeted sequencing. We discuss the identification of disease-relevant repeat element variants, further powered by the advancement of long-read sequencing technologies and their related tools, and summarize recent findings in the molecular mechanisms of repeat element variants in brain degeneration, such as those causing transcriptional silencing or RNA-mediated gain of toxic function. Furthermore, we describe how in silico predictions using innovative computational models, such as deep learning language models, could enhance and accelerate our understanding of the functional impact of repeat element variants. Finally, we discuss future directions to advance current findings for a better understanding of neurodegenerative diseases and the clinical applications of genomic repeat elements.
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Affiliation(s)
- Zhengyu An
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Aidi Jiang
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
| | - Jingqi Chen
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- MOE Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Shanghai, China
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2
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Glineburg M, Yildirim E, Gomez N, Rodriguez G, Pak J, Li X, Altheim C, Waksmacki J, McInerney G, Barmada S, Todd P. Stress granule formation helps to mitigate neurodegeneration. Nucleic Acids Res 2024; 52:9745-9759. [PMID: 39106168 PMCID: PMC11381325 DOI: 10.1093/nar/gkae655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 05/28/2024] [Accepted: 07/17/2024] [Indexed: 08/09/2024] Open
Abstract
Cellular stress pathways that inhibit translation initiation lead to transient formation of cytoplasmic RNA/protein complexes known as stress granules. Many of the proteins found within stress granules and the dynamics of stress granule formation and dissolution are implicated in neurodegenerative disease. Whether stress granule formation is protective or harmful in neurodegenerative conditions is not known. To address this, we took advantage of the alphavirus protein nsP3, which selectively binds dimers of the central stress granule nucleator protein G3BP and markedly reduces stress granule formation without directly impacting the protein translational inhibitory pathways that trigger stress granule formation. In Drosophila and rodent neurons, reducing stress granule formation with nsP3 had modest impacts on lifespan even in the setting of serial stress pathway induction. In contrast, reducing stress granule formation in models of ataxia, amyotrophic lateral sclerosis and frontotemporal dementia largely exacerbated disease phenotypes. These data support a model whereby stress granules mitigate, rather than promote, neurodegenerative cascades.
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Affiliation(s)
- M Rebecca Glineburg
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Nicolas Gomez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Cell and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Genesis Rodriguez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Jaclyn Pak
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Christopher Altheim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Jacob Waksmacki
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Gerald M McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm 17165, Sweden
| | - Sami J Barmada
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Veterans Affairs Medical Center, Ann Arbor, MI, USA
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3
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Wenzhi Y, Xiangyi L, Dongsheng F. The prion-like effect and prion-like protein targeting strategy in amyotrophic lateral sclerosis. Heliyon 2024; 10:e34963. [PMID: 39170125 PMCID: PMC11336370 DOI: 10.1016/j.heliyon.2024.e34963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 07/09/2024] [Accepted: 07/19/2024] [Indexed: 08/23/2024] Open
Abstract
Pathological proteins in amyotrophic lateral sclerosis (ALS), such as superoxide dismutase 1, TAR DNA-binding protein 43, and fused in sarcoma, exhibit a prion-like pattern. All these proteins have a low-complexity domain and seeding activity in cells. In this review, we summarize the studies on the prion-like effect of these proteins and list six prion-like protein targeting strategies that we believe have potential for ALS therapy, including antisense oligonucleotides, antibody-based technology, peptide, protein chaperone, autophagy enhancement, and heteromultivalent compounds. Considering the pathological complexity and heterogeneity of ALS, we believe that the final solution to ALS therapy is most likely to be an individualized cocktail therapy, including clearance of toxicity, blockage of pathological progress, and protection of neurons.
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Affiliation(s)
- Yang Wenzhi
- Department of Neurology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China
| | - Liu Xiangyi
- Department of Neurology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China
| | - Fan Dongsheng
- Department of Neurology, Peking University Third Hospital, Beijing, China
- Beijing Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China
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4
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Wang H, Zeng R. Aberrant protein aggregation in amyotrophic lateral sclerosis. J Neurol 2024; 271:4826-4851. [PMID: 38869826 DOI: 10.1007/s00415-024-12485-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/14/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease. As its pathological mechanisms are not well understood, there are no efficient therapeutics for it at present. While it is highly heterogenous both etiologically and clinically, it has a common salient hallmark, i.e., aberrant protein aggregation (APA). The upstream pathogenesis and the downstream effects of APA in ALS are sophisticated and the investigation of this pathology would be of consequence for understanding ALS. In this paper, the pathomechanism of APA in ALS and the candidate treatment strategies for it are discussed.
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Affiliation(s)
- Huaixiu Wang
- Department Neurology, Shanxi Provincial Peoples Hospital: Fifth Hospital of Shanxi Medical University, Taiyuan, 030012, China.
- Beijing Ai-Si-Kang Medical Technology Co. Ltd., No. 18 11th St Economical & Technological Development Zone, Beijing, 100176, China.
| | - Rong Zeng
- Department Neurology, Shanxi Provincial Peoples Hospital: Fifth Hospital of Shanxi Medical University, Taiyuan, 030012, China
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5
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Amin A, Perera ND, Tomas D, Cuic B, Radwan M, Hatters DM, Turner BJ, Shabanpoor F. Systemic administration of a novel Beclin 1-derived peptide significantly upregulates autophagy in the spinal motor neurons of autophagy reporter mice. Int J Pharm 2024; 659:124198. [PMID: 38816263 DOI: 10.1016/j.ijpharm.2024.124198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/09/2024] [Accepted: 05/01/2024] [Indexed: 06/01/2024]
Abstract
Autophagy, an intracellular degradation system, plays a vital role in protecting cells by clearing damaged organelles, pathogens, and protein aggregates. Autophagy upregulation through pharmacological interventions has gained significant attention as a potential therapeutic avenue for proteinopathies. Here, we report the development of an autophagy-inducing peptide (BCN4) derived from the Beclin 1 protein, the master regulator of autophagy. To deliver the BCN4 into cells and the central nervous system (CNS), it was conjugated to our previously developed cell and blood-brain barrier-penetrating peptide (CPP). CPP-BCN4 significantly upregulated autophagy and reduced protein aggregates in motor neuron (MN)-like cells. Moreover, its systemic administration in a reporter mouse model of autophagy resulted in a significant increase in autophagy activity in the spinal MNs. Therefore, this novel autophagy-inducing peptide with a demonstrated ability to upregulate autophagy in the CNS has significant potential for the treatment of various neurodegenerative diseases with protein aggregates as a characteristic feature.
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Affiliation(s)
- Azin Amin
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia
| | - Nirma D Perera
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia
| | - Doris Tomas
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia
| | - Brittany Cuic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia
| | - Mona Radwan
- Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville 3010, VIC, Australia
| | - Danny M Hatters
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville 3010, VIC, Australia
| | - Bradley J Turner
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia
| | - Fazel Shabanpoor
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3010, VIC, Australia; School of Chemistry, University of Melbourne, VIC 3010, Australia.
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6
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Sirozh O, Saez-Mas A, Jung B, Sanchez-Burgos L, Zarzuela E, Rodrigo-Perez S, Ventoso I, Lafarga V, Fernandez-Capetillo O. Nucleolar stress caused by arginine-rich peptides triggers a ribosomopathy and accelerates aging in mice. Mol Cell 2024; 84:1527-1540.e7. [PMID: 38521064 DOI: 10.1016/j.molcel.2024.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 01/11/2024] [Accepted: 02/26/2024] [Indexed: 03/25/2024]
Abstract
Nucleolar stress (NS) has been associated with age-related diseases such as cancer or neurodegeneration. To investigate how NS triggers toxicity, we used (PR)n arginine-rich peptides present in some neurodegenerative diseases as inducers of this perturbation. We here reveal that whereas (PR)n expression leads to a decrease in translation, this occurs concomitant with an accumulation of free ribosomal (r) proteins. Conversely, (PR)n-resistant cells have lower rates of r-protein synthesis, and targeting ribosome biogenesis by mTOR inhibition or MYC depletion alleviates (PR)n toxicity in vitro. In mice, systemic expression of (PR)97 drives widespread NS and accelerated aging, which is alleviated by rapamycin. Notably, the generalized accumulation of orphan r-proteins is a common outcome of chemical or genetic perturbations that induce NS. Together, our study presents a general model to explain how NS induces cellular toxicity and provides in vivo evidence supporting a role for NS as a driver of aging in mammals.
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Affiliation(s)
- Oleksandra Sirozh
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Anabel Saez-Mas
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Bomi Jung
- Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 21 Stockholm, Sweden
| | - Laura Sanchez-Burgos
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Eduardo Zarzuela
- Proteomics Unit, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Sara Rodrigo-Perez
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain
| | - Ivan Ventoso
- Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), Departamento de Biologia Molecular, Universidad Autonoma de Madrid (UAM), Madrid, Spain
| | - Vanesa Lafarga
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain.
| | - Oscar Fernandez-Capetillo
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029, Spain; Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 21 Stockholm, Sweden.
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7
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Gupta MN, Uversky VN. Biological importance of arginine: A comprehensive review of the roles in structure, disorder, and functionality of peptides and proteins. Int J Biol Macromol 2024; 257:128646. [PMID: 38061507 DOI: 10.1016/j.ijbiomac.2023.128646] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/02/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024]
Abstract
Arginine shows Jekyll and Hyde behavior in several respects. It participates in protein folding via ionic and H-bonds and cation-pi interactions; the charge and hydrophobicity of its side chain make it a disorder-promoting amino acid. Its methylation in histones; RNA binding proteins; chaperones regulates several cellular processes. The arginine-centric modifications are important in oncogenesis and as biomarkers in several cardiovascular diseases. The cross-links involving arginine in collagen and cornea are involved in pathogenesis of tissues but have also been useful in tissue engineering and wound-dressing materials. Arginine is a part of active site of several enzymes such as GTPases, peroxidases, and sulfotransferases. Its metabolic importance is obvious as it is involved in production of urea, NO, ornithine and citrulline. It can form unusual functional structures such as molecular tweezers in vitro and sprockets which engage DNA chains as part of histones in vivo. It has been used in design of cell-penetrating peptides as drugs. Arginine has been used as an excipient in both solid and injectable drug formulations; its role in suppressing opalescence due to liquid-liquid phase separation is particularly very promising. It has been known as a suppressor of protein aggregation during protein refolding. It has proved its usefulness in protein bioseparation processes like ion-exchange, hydrophobic and affinity chromatographies. Arginine is an amino acid, whose importance in biological sciences and biotechnology continues to grow in diverse ways.
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Affiliation(s)
- Munishwar Nath Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
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8
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Geng Y, Cai Q. Role of C9orf72 hexanucleotide repeat expansions in ALS/FTD pathogenesis. Front Mol Neurosci 2024; 17:1322720. [PMID: 38318532 PMCID: PMC10838790 DOI: 10.3389/fnmol.2024.1322720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive neurological disorders that share neurodegenerative pathways and features. The most prevalent genetic causes of ALS/FTD is the GGGGCC hexanucleotide repeat expansions in the first intron region of the chromosome 9 open reading frame 72 (C9orf72) gene. In this review, we comprehensively summarize the accumulating evidences elucidating the pathogenic mechanism associated with hexanucleotide repeat expansions in ALS/FTD. These mechanisms encompass the structural polymorphism of DNA and transcribed RNA, the formation of RNA foci via phase separation, and the cytoplasmic accumulation and toxicities of dipeptide-repeat proteins. Additionally, the formation of G-quadruplex structures significantly impairs the expression and normal function of the C9orf72 protein. We also discuss the sequestration of specific RNA binding proteins by GGGGCC RNA, which further contributes to the toxicity of C9orf72 hexanucleotide repeat expansions. The deeper understanding of the pathogenic mechanism of hexanucleotide repeat expansions in ALS/FTD provides multiple potential drug targets for these devastating diseases.
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Affiliation(s)
- Yanyan Geng
- Clinical Research Institute of the First Affiliated Hospital of Xiamen University, Fujian Key Laboratory of Brain Tumors Diagnosis and Precision Treatment, Xiamen Key Laboratory of Brain Center, the First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Qixu Cai
- State Key Laboratory of Vaccines for Infectious Diseases, School of Public Health, Xiamen University, Xiamen, Fujian, China
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9
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Smeele PH, Cesare G, Vaccari T. ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis. Cells 2024; 13:178. [PMID: 38247869 PMCID: PMC10813877 DOI: 10.3390/cells13020178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Protein homeostasis is essential for neuron longevity, requiring a balanced regulation between protein synthesis and degradation. The clearance of misfolded and aggregated proteins, mediated by autophagy and the ubiquitin-proteasome systems, maintains protein homeostasis in neurons, which are post-mitotic and thus cannot use cell division to diminish the burden of misfolded proteins. When protein clearance pathways are overwhelmed or otherwise disrupted, the accumulation of misfolded or aggregated proteins can lead to the activation of ER stress and the formation of stress granules, which predominantly attempt to restore the homeostasis by suppressing global protein translation. Alterations in these processes have been widely reported among studies investigating the toxic function of dipeptide repeats (DPRs) produced by G4C2 expansion in the C9orf72 gene of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this review, we outline the modalities of DPR-induced disruptions in protein homeostasis observed in a wide range of models of C9orf72-linked ALS/FTD. We also discuss the relative importance of each DPR for toxicity, possible synergies between DPRs, and discuss the possible functional relevance of DPR aggregation to disease pathogenesis. Finally, we highlight the interdependencies of the observed effects and reflect on the importance of feedback and feedforward mechanisms in their contribution to disease progression. A better understanding of DPR-associated disease pathogenesis discussed in this review might shed light on disease vulnerabilities that may be amenable with therapeutic interventions.
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Affiliation(s)
| | | | - Thomas Vaccari
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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10
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Glineburg MR, Yildirim E, Gomez N, Li X, Pak J, Altheim C, Waksmacki J, McInerney G, Barmada SJ, Todd PK. Stress granule formation helps to mitigate neurodegeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566060. [PMID: 37986813 PMCID: PMC10659376 DOI: 10.1101/2023.11.07.566060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Cellular stress pathways that inhibit translation initiation lead to transient formation of cytoplasmic RNA/protein complexes known as stress granules. Many of the proteins found within stress granules and the dynamics of stress granule formation and dissolution are implicated in neurodegenerative disease. Whether stress granule formation is protective or harmful in neurodegenerative conditions is not known. To address this, we took advantage of the alphavirus protein nsP3, which selectively binds dimers of the central stress granule nucleator protein G3BP (rin in Drosophila) and markedly reduces stress granule formation without directly impacting the protein translational inhibitory pathways that trigger stress granule formation. In Drosophila and rodent neurons, reducing stress granule formation with nsP3 had modest impacts on lifespan even in the setting of serial stress pathway induction. In contrast, reducing stress granule formation in models of ataxia, amyotrophic lateral sclerosis and frontotemporal dementia largely exacerbated disease phenotypes. These data support a model whereby stress granules mitigate, rather than promote, neurodegenerative cascades.
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Affiliation(s)
- M. Rebecca Glineburg
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 450 N. Center St, Orange, CA 92866
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Nicolas Gomez
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Xingli Li
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Jaclyn Pak
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 450 N. Center St, Orange, CA 92866
| | - Christopher Altheim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Jacob Waksmacki
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Gerald McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Sami J. Barmada
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
| | - Peter K. Todd
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI, 4005 BSRB48109-2200, USA
- Veterans Affairs Medical Center, Ann Arbor, MI, USA
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11
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Fu RH, Chen HJ, Hong SY. Glycine-Alanine Dipeptide Repeat Protein from C9-ALS Interacts with Sulfide Quinone Oxidoreductase (SQOR) to Induce the Activity of the NLRP3 Inflammasome in HMC3 Microglia: Irisflorentin Reverses This Interaction. Antioxidants (Basel) 2023; 12:1896. [PMID: 37891975 PMCID: PMC10604625 DOI: 10.3390/antiox12101896] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/07/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal rare disease of progressive degeneration of motor neurons. The most common genetic mutation in ALS is the hexanucleotide repeat expansion (HRE) located in the first intron of the C9orf72 gene (C9-ALS). HRE can produce dipeptide repeat proteins (DPRs) such as poly glycine-alanine (GA) in a repeat-associated non-ATG (RAN) translation. GA-DPR has been shown to be toxic to motor neurons in various biological models. However, its effects on microglia involved in C9-ALS have not been reported. Here, we show that GA-DPR (GA50) activates the NLR family pyrin domain containing 3 (NLRP3) inflammasome in a human HMC3 microglia model. MCC950 (specific inhibitor of the NLRP3) treatment can abrogate this activity. Next, using yeast two-hybrid screening, we identified sulfide quinone oxidoreductase (SQOR) as a GA50 interacting protein. SQOR knockdown in HMC3 cells can significantly induce the activity of the NLRP3 inflammasome by upregulating the level of intracellular reactive oxygen species and the cytoplasmic escape of mitochondrial DNA. Furthermore, we obtained irisflorentin as an effective blocker of the interaction between SQOR and GA50, thus inhibiting NLRP3 inflammasome activity in GA50-expressing HMC3 cells. These results imply the association of GA-DPR, SQOR, and NLRP3 inflammasomes in microglia and establish a treatment strategy for C9-ALS with irisflorentin.
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Affiliation(s)
- Ru-Huei Fu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Translational Medicine Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Ph.D. Program for Aging, China Medical University, Taichung 40402, Taiwan
| | - Hui-Jye Chen
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
| | - Syuan-Yu Hong
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Department of Medicine, School of Medicine, China Medical University, Taichung 40447, Taiwan
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
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12
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Kinger S, Dubey AR, Kumar P, Jagtap YA, Choudhary A, Kumar A, Prajapati VK, Dhiman R, Mishra A. Molecular Chaperones' Potential against Defective Proteostasis of Amyotrophic Lateral Sclerosis. Cells 2023; 12:cells12091302. [PMID: 37174703 PMCID: PMC10177248 DOI: 10.3390/cells12091302] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neuronal degenerative condition identified via a build-up of mutant aberrantly folded proteins. The native folding of polypeptides is mediated by molecular chaperones, preventing their pathogenic aggregation. The mutant protein expression in ALS is linked with the entrapment and depletion of chaperone capacity. The lack of a thorough understanding of chaperones' involvement in ALS pathogenesis presents a significant challenge in its treatment. Here, we review how the accumulation of the ALS-linked mutant FUS, TDP-43, SOD1, and C9orf72 proteins damage cellular homeostasis mechanisms leading to neuronal loss. Further, we discuss how the HSP70 and DNAJ family co-chaperones can act as potential targets for reducing misfolded protein accumulation in ALS. Moreover, small HSPB1 and HSPB8 chaperones can facilitate neuroprotection and prevent stress-associated misfolded protein apoptosis. Designing therapeutic strategies by pharmacologically enhancing cellular chaperone capacity to reduce mutant protein proteotoxic effects on ALS pathomechanisms can be a considerable advancement. Chaperones, apart from directly interacting with misfolded proteins for protein quality control, can also filter their toxicity by initiating strong stress-response pathways, modulating transcriptional expression profiles, and promoting anti-apoptotic functions. Overall, these properties of chaperones make them an attractive target for gaining fundamental insights into misfolded protein disorders and designing more effective therapies against ALS.
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Affiliation(s)
- Sumit Kinger
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Ankur Rakesh Dubey
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Prashant Kumar
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Yuvraj Anandrao Jagtap
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Akash Choudhary
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
| | - Amit Kumar
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer 305817, India
| | - Rohan Dhiman
- Laboratory of Mycobacterial Immunology, Department of Life Science, National Institute of Technology, Rourkela 769008, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur 342037, India
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13
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Parameswaran J, Zhang N, Braems E, Tilahun K, Pant DC, Yin K, Asress S, Heeren K, Banerjee A, Davis E, Schwartz SL, Conn GL, Bassell GJ, Van Den Bosch L, Jiang J. Antisense, but not sense, repeat expanded RNAs activate PKR/eIF2α-dependent ISR in C9ORF72 FTD/ALS. eLife 2023; 12:e85902. [PMID: 37073950 PMCID: PMC10188109 DOI: 10.7554/elife.85902] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 04/18/2023] [Indexed: 04/20/2023] Open
Abstract
GGGGCC (G4C2) hexanucleotide repeat expansion in the C9ORF72 gene is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The repeat is bidirectionally transcribed and confers gain of toxicity. However, the underlying toxic species is debated, and it is not clear whether antisense CCCCGG (C4G2) repeat expanded RNAs contribute to disease pathogenesis. Our study shows that C9ORF72 antisense C4G2 repeat expanded RNAs trigger the activation of the PKR/eIF2α-dependent integrated stress response independent of dipeptide repeat proteins that are produced through repeat-associated non-AUG-initiated translation, leading to global translation inhibition and stress granule formation. Reducing PKR levels with either siRNA or morpholinos mitigates integrated stress response and toxicity caused by the antisense C4G2 RNAs in cell lines, primary neurons, and zebrafish. Increased phosphorylation of PKR/eIF2α is also observed in the frontal cortex of C9ORF72 FTD/ALS patients. Finally, only antisense C4G2, but not sense G4C2, repeat expanded RNAs robustly activate the PKR/eIF2α pathway and induce aberrant stress granule formation. These results provide a mechanism by which antisense C4G2 repeat expanded RNAs elicit neuronal toxicity in FTD/ALS caused by C9ORF72 repeat expansions.
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Affiliation(s)
| | - Nancy Zhang
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Elke Braems
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU LeuvenLeuvenBelgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Campus GasthuisbergLeuvenBelgium
| | | | - Devesh C Pant
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Keena Yin
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Seneshaw Asress
- Department of Neurology, Emory UniversityAtlantaUnited States
| | - Kara Heeren
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU LeuvenLeuvenBelgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Campus GasthuisbergLeuvenBelgium
| | - Anwesha Banerjee
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Emma Davis
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | | | - Graeme L Conn
- Department of Biochemistry, Emory UniversityAtlantaUnited States
| | - Gary J Bassell
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU LeuvenLeuvenBelgium
- Center for Brain & Disease Research, Laboratory of Neurobiology, VIB, Campus GasthuisbergLeuvenBelgium
| | - Jie Jiang
- Department of Cell Biology, Emory UniversityAtlantaUnited States
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14
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Vanecek AS, Mojsilovic-Petrovic J, Kalb RG, Tepe JJ. Enhanced Degradation of Mutant C9ORF72-Derived Toxic Dipeptide Repeat Proteins by 20S Proteasome Activation Results in Restoration of Proteostasis and Neuroprotection. ACS Chem Neurosci 2023. [PMID: 37015082 DOI: 10.1021/acschemneuro.2c00732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
A hexanucleotide repeat expansion (HRE) in an intron of gene C9ORF72 is the most common cause of familial amyotrophic lateral sclerosis and frontotemporal dementia. The HRE undergoes noncanonical translation (repeat-associated non-ATG translation) resulting in the production of five distinct dipeptide repeat (DPR) proteins. Arginine-rich DPR proteins have shown to be toxic to motor neurons, and recent evidence suggests this toxicity is associated with disruption of the ubiquitin-proteasome system. Here we report the ability of known 20S proteasome activator, TCH-165, to enhance the degradation of DPR proteins and overcome proteasome impairment evoked by DPR proteins. Furthermore, the 20S activator protects rodent motor neurons from DPR protein toxicity and restores proteostasis in cortical neuron cultures. This study suggests that 20S proteasome enhancers may have therapeutic efficacy in neurodegenerative diseases that display proteostasis defects.
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Affiliation(s)
- Allison S Vanecek
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jelena Mojsilovic-Petrovic
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Robert G Kalb
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Jetze J Tepe
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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15
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Tu WY, Xu W, Zhang J, Qi S, Bai L, Shen C, Zhang K. C9orf72 poly-GA proteins impair neuromuscular transmission. Zool Res 2023; 44:331-340. [PMID: 36799225 PMCID: PMC10083233 DOI: 10.24272/j.issn.2095-8137.2022.356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating motoneuron disease, in which lower motoneurons lose control of skeletal muscles. Degeneration of neuromuscular junctions (NMJs) occurs at the initial stage of ALS. Dipeptide repeat proteins (DPRs) from G4C2 repeat-associated non-ATG (RAN) translation are known to cause C9orf72-associated ALS (C9-ALS). However, DPR inclusion burdens are weakly correlated with neurodegenerative areas in C9-ALS patients, indicating that DPRs may exert cell non-autonomous effects, in addition to the known intracellular pathological mechanisms. Here, we report that poly-GA, the most abundant form of DPR in C9-ALS, is released from cells. Local administration of poly-GA proteins in peripheral synaptic regions causes muscle weakness and impaired neuromuscular transmission in vivo. The NMJ structure cannot be maintained, as evidenced by the fragmentation of postsynaptic acetylcholine receptor (AChR) clusters and distortion of presynaptic nerve terminals. Mechanistic study demonstrated that extracellular poly-GA sequesters soluble Agrin ligands and inhibits Agrin-MuSK signaling. Our findings provide a novel cell non-autonomous mechanism by which poly-GA impairs NMJs in C9-ALS. Thus, targeting NMJs could be an early therapeutic intervention for C9-ALS.
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Affiliation(s)
- Wen-Yo Tu
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
| | - Wentao Xu
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
| | - Jianmin Zhang
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
| | - Shuyuan Qi
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
| | - Lei Bai
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
| | - Chengyong Shen
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China
- MOE Frontier Science, Center for Brain Research and Brain-Machine Integration, Zhejiang University, Hangzhou, Zhejiang 310058, China. E-mail:
| | - Kejing Zhang
- Zhejiang Provincial Key Laboratory of Pancreatic Disease, Department of Neurobiology, First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310020, China. E-mail:
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16
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Shu X, Wei C, Tu WY, Zhong K, Qi S, Wang A, Bai L, Zhang SX, Luo B, Xu ZZ, Zhang K, Shen C. Negative regulation of TREM2-mediated C9orf72 poly-GA clearance by the NLRP3 inflammasome. Cell Rep 2023; 42:112133. [PMID: 36800288 DOI: 10.1016/j.celrep.2023.112133] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 11/30/2022] [Accepted: 01/31/2023] [Indexed: 02/18/2023] Open
Abstract
Expansion of the hexanucleotide repeat GGGGCC in the C9orf72 gene is the most common genetic factor in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Poly-Gly-Ala (poly-GA), one form of dipeptide repeat proteins (DPRs) produced from GGGGCC repeats, tends to form neurotoxic protein aggregates. The C9orf72 GGGGCC repeats and microglial receptor TREM2 are both associated with risk for ALS/FTD. The role and regulation of TREM2 in C9orf72-ALS/FTD remain unclear. Here, we found that poly-GA proteins activate the microglial NLRP3 inflammasome to produce interleukin-1β (IL-1β), which promotes ADAM10-mediated TREM2 cleavage and inhibits phagocytosis of poly-GA. The inhibitor of the NLRP3 inflammasome, MCC950, reduces the TREM2 cleavage and poly-GA aggregates, resulting in the alleviation of motor deficits in poly-GA mice. Our study identifies a crosstalk between NLRP3 and TREM2 signaling, suggesting that targeting the NLRP3 inflammasome to sustain TREM2 is an approach to treat C9orf72-ALS/FTD.
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Affiliation(s)
- Xiaoqiu Shu
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Chen Wei
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Wen-Yo Tu
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Keke Zhong
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Shuyuan Qi
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Ailian Wang
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Lei Bai
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Shan-Xin Zhang
- School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China; MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University, Hangzhou 310058, China
| | - Benyan Luo
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China
| | - Zhen-Zhong Xu
- School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China; MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University, Hangzhou 310058, China
| | - Kejing Zhang
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China.
| | - Chengyong Shen
- Department of Neurobiology of First Affiliated Hospital, Zhejiang Provincial Key Laboratory of Pancreatic Disease, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310020, China; MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University, Hangzhou 310058, China.
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17
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Paul S, Dansithong W, Gandelman M, Figueroa KP, Zu T, Ranum LPW, Scoles DR, Pulst SM. Staufen Impairs Autophagy in Neurodegeneration. Ann Neurol 2023; 93:398-416. [PMID: 36151701 PMCID: PMC9892312 DOI: 10.1002/ana.26515] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The mechanistic target of rapamycin (mTOR) kinase is one of the master coordinators of cellular stress responses, regulating metabolism, autophagy, and apoptosis. We recently reported that staufen1 (STAU1), a stress granule (SG) protein, was overabundant in fibroblast cell lines from patients with spinocerebellar ataxia type 2 (SCA2), amyotrophic lateral sclerosis, frontotemporal degeneration, Huntington's, Alzheimer's, and Parkinson's diseases as well as animal models, and patient tissues. STAU1 overabundance is associated with mTOR hyperactivation and links SG formation with autophagy. Our objective was to determine the mechanism of mTOR regulation by STAU1. METHODS We determined STAU1 abundance with disease- and chemical-induced cellular stressors in patient cells and animal models. We also used RNA-binding assays to contextualize STAU1 interaction with MTOR mRNA. RESULTS STAU1 and mTOR were overabundant in bacterial artificial chromosome (BAC)-C9ORF72, ATXN2Q127 , and Thy1-TDP-43 transgenic mouse models. Reducing STAU1 levels in these mice normalized mTOR levels and activity and autophagy-related marker proteins. We also saw increased STAU1 levels in HEK293 cells transfected to express C9ORF72-relevant dipeptide repeats (DPRs). Conversely, DPR accumulations were not observed in cells treated by STAU1 RNA interference (RNAi). Overexpression of STAU1 in HEK293 cells increased mTOR levels through direct MTOR mRNA interaction, activating downstream targets and impairing autophagic flux. Targeting mTOR by rapamycin or RNAi normalized STAU1 abundance in an SCA2 cellular model. INTERPRETATION STAU1 interaction with mTOR drives its hyperactivation and inhibits autophagic flux in multiple models of neurodegeneration. Staufen, therefore, constitutes a novel target to modulate mTOR activity and autophagy, and for the treatment of neurodegenerative diseases. ANN NEUROL 2023;93:398-416.
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Affiliation(s)
- Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, UT
| | | | - Mandi Gandelman
- Department of Neurology, University of Utah, Salt Lake City, UT
| | | | - Tao Zu
- Center for NeuroGenetics and Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Laura P W Ranum
- Center for NeuroGenetics and Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Daniel R Scoles
- Department of Neurology, University of Utah, Salt Lake City, UT
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT
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18
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Kaliszewska A, Allison J, Col TT, Shaw C, Arias N. Elucidating the Role of Cerebellar Synaptic Dysfunction in C9orf72-ALS/FTD - a Systematic Review and Meta-Analysis. CEREBELLUM (LONDON, ENGLAND) 2022; 21:681-714. [PMID: 34491551 PMCID: PMC9325807 DOI: 10.1007/s12311-021-01320-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 12/28/2022]
Abstract
A hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) with synaptic dysfunction identified as an early pathological hallmark. Although TDP-43 pathology and overt neurodegeneration are largely absent from the cerebellum, the pathological hallmarks of RNA foci and dipeptide repeat protein (DPR) inclusions are most abundant. Here, we present a systematic literature search in the databases of PubMed, Scopus, Embase, Web of Science and Science Direct up until March 5, 2021, which yielded 19,515 publications. Following the exclusion criteria, 72 articles were included having referred to C9orf72, synapses and the cerebellum. Meta-analyses were conducted on studies which reported experimental and control groups with means and standard deviations extracted from figures using the online tool PlotDigitizer. This revealed dendritic defects (P = 0.03), reduced C9orf72 in human patients (P = 0.005) and DPR-related neuronal loss (P = 0.0006) but no neuromuscular junction abnormalities (P = 0.29) or cerebellar neuronal loss (P = 0.23). Our results suggest that dendritic arborisation defects, synaptic gene dysregulation and altered synaptic neurotransmission may drive cerebellar synaptic dysfunction in C9-ALS/FTD. In this review, we discuss how the chronological appearance of the different pathological hallmarks alters synaptic integrity which may have profound implications for disease progression. We conclude that a reduction in C9orf72 protein levels combined with the accumulation of RNA foci and DPRs act synergistically to drive C9 synaptopathy in the cerebellum of C9-ALS/FTD patients.
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Affiliation(s)
- Aleksandra Kaliszewska
- UK Dementia Research Institute At King's College London, Institute of Psychiatry, Psychology and Neuroscience, Department of Basic & Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe road, Camberwell, SE59RX, London, UK
| | - Joseph Allison
- UK Dementia Research Institute At King's College London, Institute of Psychiatry, Psychology and Neuroscience, Department of Basic & Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe road, Camberwell, SE59RX, London, UK
| | - Tarik-Tarkan Col
- UK Dementia Research Institute At King's College London, Institute of Psychiatry, Psychology and Neuroscience, Department of Basic & Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe road, Camberwell, SE59RX, London, UK
| | - Christopher Shaw
- UK Dementia Research Institute At King's College London, Institute of Psychiatry, Psychology and Neuroscience, Department of Basic & Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe road, Camberwell, SE59RX, London, UK
- Centre for Brain Research, University of Auckland, 85 Grafton Road, Auckland, 1023, New Zealand
| | - Natalia Arias
- UK Dementia Research Institute At King's College London, Institute of Psychiatry, Psychology and Neuroscience, Department of Basic & Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe road, Camberwell, SE59RX, London, UK.
- INEUROPA, Instituto de Neurociencias del Principado de Asturias, Plaza Feijoo s/n, 33003, Oviedo, Spain.
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19
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Gleixner AM, Verdone BM, Otte CG, Anderson EN, Ramesh N, Shapiro OR, Gale JR, Mauna JC, Mann JR, Copley KE, Daley EL, Ortega JA, Cicardi ME, Kiskinis E, Kofler J, Pandey UB, Trotti D, Donnelly CJ. NUP62 localizes to ALS/FTLD pathological assemblies and contributes to TDP-43 insolubility. Nat Commun 2022; 13:3380. [PMID: 35697676 PMCID: PMC9192689 DOI: 10.1038/s41467-022-31098-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 06/03/2022] [Indexed: 01/12/2023] Open
Abstract
A G4C2 hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic cause of ALS and FTLD (C9-ALS/FTLD) with cytoplasmic TDP-43 inclusions observed in regions of neurodegeneration. The accumulation of repetitive RNAs and dipeptide repeat protein (DPR) are two proposed mechanisms of toxicity in C9-ALS/FTLD and linked to impaired nucleocytoplasmic transport. Nucleocytoplasmic transport is regulated by the phenylalanine-glycine nucleoporins (FG nups) that comprise the nuclear pore complex (NPC) permeability barrier. However, the relationship between FG nups and TDP-43 pathology remains elusive. Our studies show that nuclear depletion and cytoplasmic mislocalization of one FG nup, NUP62, is linked to TDP-43 mislocalization in C9-ALS/FTLD iPSC neurons. Poly-glycine arginine (GR) DPR accumulation initiates the formation of cytoplasmic RNA granules that recruit NUP62 and TDP-43. Cytoplasmic NUP62 and TDP-43 interactions promotes their insolubility and NUP62:TDP-43 inclusions are frequently found in C9orf72 ALS/FTLD as well as sporadic ALS/FTLD postmortem CNS tissue. Our findings indicate NUP62 cytoplasmic mislocalization contributes to TDP-43 proteinopathy in ALS/FTLD.
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Affiliation(s)
- Amanda M Gleixner
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Brandie Morris Verdone
- Department of Neuroscience, Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Charlton G Otte
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
- Physician Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Eric N Anderson
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Nandini Ramesh
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA
| | - Olivia R Shapiro
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Jenna R Gale
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Jocelyn C Mauna
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Jacob R Mann
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Katie E Copley
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
| | - Elizabeth L Daley
- The Ken & Ruth Davee Department of Neurology, Northwestern University of Feinberg School of Medicine, Chicago, IL, USA
| | - Juan A Ortega
- The Ken & Ruth Davee Department of Neurology, Northwestern University of Feinberg School of Medicine, Chicago, IL, USA
| | - Maria Elena Cicardi
- Department of Neuroscience, Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Northwestern University of Feinberg School of Medicine, Chicago, IL, USA
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Julia Kofler
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Udai B Pandey
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Davide Trotti
- Department of Neuroscience, Jefferson Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Christopher J Donnelly
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
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20
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Liu F, Morderer D, Wren MC, Vettleson-Trutza SA, Wang Y, Rabichow BE, Salemi MR, Phinney BS, Oskarsson B, Dickson DW, Rossoll W. Proximity proteomics of C9orf72 dipeptide repeat proteins identifies molecular chaperones as modifiers of poly-GA aggregation. Acta Neuropathol Commun 2022; 10:22. [PMID: 35164882 PMCID: PMC8842533 DOI: 10.1186/s40478-022-01322-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/14/2022] Open
Abstract
The most common inherited cause of two genetically and clinico-pathologically overlapping neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), is the presence of expanded GGGGCC intronic hexanucleotide repeats in the C9orf72 gene. Aside from haploinsufficiency and toxic RNA foci, another non-exclusive disease mechanism is the non-canonical translation of the repeat RNA into five different dipeptide repeat proteins (DPRs), which form neuronal inclusions in affected patient brains. While evidence from cellular and animal models supports a toxic gain-of-function of pathologic poly-GA, poly-GR, and poly-PR aggregates in promoting deposition of TDP-43 pathology and neurodegeneration in affected brain areas, the relative contribution of DPRs to the disease process in c9FTD/ALS patients remains unclear. Here we have used the proximity-dependent biotin identification (BioID) proximity proteomics approach to investigate the formation and collective composition of DPR aggregates using cellular models. While interactomes of arginine rich poly-GR and poly-PR aggregates overlapped and were enriched for nucleolar and ribosomal proteins, poly-GA aggregates demonstrated a distinct association with proteasomal components, molecular chaperones (HSPA1A/HSP70, HSPA8/HSC70, VCP/p97), co-chaperones (BAG3, DNAJA1A) and other factors that regulate protein folding and degradation (SQSTM1/p62, CALR, CHIP/STUB1). Experiments in cellular models of poly-GA pathology show that molecular chaperones and co-chaperones are sequestered to the periphery of dense cytoplasmic aggregates, causing depletion from their typical cellular localization. Their involvement in the pathologic process is confirmed in autopsy brain tissue, where HSPA8, BAG3, VCP, and its adapter protein UBXN6 show a close association with poly-GA aggregates in the frontal cortex, temporal cortex, and hippocampus of c9FTLD and c9ALS cases. The association of heat shock proteins and co-chaperones with poly-GA led us to investigate their potential role in reducing its aggregation. We identified HSP40 co-chaperones of the DNAJB family as potent modifiers that increased the solubility of poly-GA, highlighting a possible novel therapeutic avenue and a central role of molecular chaperones in the pathogenesis of human C9orf72-linked diseases.
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21
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Del Rosso G, Carlomagno Y, Todd TW, Jones CY, Prudencio M, Daughrity LM, Yue M, Jansen-West K, Tong J, Shao W, Wu Y, Castanedes-Casey M, Tabassian L, Oskarsson B, Ling K, Rigo F, Dickson DW, Yao TP, Petrucelli L, Cook CN, Zhang YJ. HDAC6 Interacts With Poly (GA) and Modulates its Accumulation in c9FTD/ALS. Front Cell Dev Biol 2022; 9:809942. [PMID: 35096836 PMCID: PMC8790530 DOI: 10.3389/fcell.2021.809942] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
The aberrant translation of a repeat expansion in chromosome 9 open reading frame 72 (C9orf72), the most common cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), results in the accumulation of toxic dipeptide repeat (DPR) proteins in the central nervous system We have found that, among the sense DPR proteins, HDAC6 specifically interacts with the poly (GA) and co-localizes with inclusions in both patient tissue and a mouse model of this disease (c9FTD/ALS). Overexpression of HDAC6 increased poly (GA) levels in cultured cells independently of HDAC6 deacetylase activity, suggesting that HDAC6 can modulate poly (GA) pathology through a mechanism that depends upon their physical interaction. Moreover, decreasing HDAC6 expression by stereotaxic injection of antisense oligonucleotides significantly reduced the number of poly (GA) inclusions in c9FTD/ALS mice. These findings suggest that pharmacologically reducing HDAC6 levels could be of therapeutic value in c9FTD/ALS.
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Affiliation(s)
- Giulia Del Rosso
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
| | - Yari Carlomagno
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Tiffany W Todd
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Caroline Y Jones
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Mercedes Prudencio
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
| | | | - Mei Yue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Jimei Tong
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Yanwei Wu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | | | - Lilia Tabassian
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
| | - Björn Oskarsson
- Department of Neurology, Mayo Clinic, Jacksonville, FL, United States
| | - Karen Ling
- Ionis Pharmaceuticals, Carlsbad, CA, United States
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, United States
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
| | - Tso-Pang Yao
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
| | - Casey N Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
| | - Yong Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, United States
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22
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Licata NV, Cristofani R, Salomonsson S, Wilson KM, Kempthorne L, Vaizoglu D, D’Agostino VG, Pollini D, Loffredo R, Pancher M, Adami V, Bellosta P, Ratti A, Viero G, Quattrone A, Isaacs AM, Poletti A, Provenzani A. C9orf72 ALS/FTD dipeptide repeat protein levels are reduced by small molecules that inhibit PKA or enhance protein degradation. EMBO J 2022; 41:e105026. [PMID: 34791698 PMCID: PMC8724771 DOI: 10.15252/embj.2020105026] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 09/21/2021] [Accepted: 10/12/2021] [Indexed: 11/09/2022] Open
Abstract
Intronic GGGGCC (G4C2) hexanucleotide repeat expansion within the human C9orf72 gene represents the most common cause of familial forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9ALS/FTD). Repeat-associated non-AUG (RAN) translation of repeat-containing C9orf72 RNA results in the production of neurotoxic dipeptide-repeat proteins (DPRs). Here, we developed a high-throughput drug screen for the identification of positive and negative modulators of DPR levels. We found that HSP90 inhibitor geldanamycin and aldosterone antagonist spironolactone reduced DPR levels by promoting protein degradation via the proteasome and autophagy pathways respectively. Surprisingly, cAMP-elevating compounds boosting protein kinase A (PKA) activity increased DPR levels. Inhibition of PKA activity, by both pharmacological and genetic approaches, reduced DPR levels in cells and rescued pathological phenotypes in a Drosophila model of C9ALS/FTD. Moreover, knockdown of PKA-catalytic subunits correlated with reduced translation efficiency of DPRs, while the PKA inhibitor H89 reduced endogenous DPR levels in C9ALS/FTD patient-derived iPSC motor neurons. Together, our results suggest new and druggable pathways modulating DPR levels in C9ALS/FTD.
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Affiliation(s)
- Nausicaa V Licata
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Riccardo Cristofani
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Sally Salomonsson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Katherine M Wilson
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Liam Kempthorne
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Deniz Vaizoglu
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Vito G D’Agostino
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Daniele Pollini
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Rosa Loffredo
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Michael Pancher
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Valentina Adami
- HTS Core Facility, Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Paola Bellosta
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
- Department of MedicineNYU at Grossman School of MedicineNYUSA
| | - Antonia Ratti
- Department of NeurologyStroke Unit and Laboratory of NeuroscienceIstituto Auxologico Italiano, IRCCSMilanItaly
- Dipartimento di Biotecnologie Mediche e Medicina TraslazionaleUniversità degli Studi di MilanoMilanItaly
| | | | - Alessandro Quattrone
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
| | - Adrian M Isaacs
- Department of Neurodegenerative DiseaseUCL Queen Square Institute of NeurologyLondonUK
- UK Dementia Research Institute at UCLUCL Queen Square Institute of NeurologyLondonUK
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e BiomolecolariUniversità degli Studi di MilanoMilanItaly
| | - Alessandro Provenzani
- Department of Cellular, Computational and Integrative BiologyUniversity of TrentoTrentoItaly
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23
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Ramic M, Andrade NS, Rybin MJ, Esanov R, Wahlestedt C, Benatar M, Zeier Z. Epigenetic Small Molecules Rescue Nucleocytoplasmic Transport and DNA Damage Phenotypes in C9ORF72 ALS/FTD. Brain Sci 2021; 11:brainsci11111543. [PMID: 34827542 PMCID: PMC8616043 DOI: 10.3390/brainsci11111543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/11/2021] [Accepted: 11/18/2021] [Indexed: 01/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease with available treatments only marginally slowing progression or improving survival. A hexanucleotide repeat expansion mutation in the C9ORF72 gene is the most commonly known genetic cause of both sporadic and familial cases of ALS and frontotemporal dementia (FTD). The C9ORF72 expansion mutation produces five dipeptide repeat proteins (DPRs), and while the mechanistic determinants of DPR-mediated neurotoxicity remain incompletely understood, evidence suggests that disruption of nucleocytoplasmic transport and increased DNA damage contributes to pathology. Therefore, characterizing these disturbances and determining the relative contribution of different DPRs is needed to facilitate the development of novel therapeutics for C9ALS/FTD. To this end, we generated a series of nucleocytoplasmic transport “biosensors”, composed of the green fluorescent protein (GFP), fused to different classes of nuclear localization signals (NLSs) and nuclear export signals (NESs). Using these biosensors in conjunction with automated microscopy, we investigated the role of the three most neurotoxic DPRs (PR, GR, and GA) on seven nuclear import and two export pathways. In addition to other DPRs, we found that PR had pronounced inhibitory effects on the classical nuclear export pathway and several nuclear import pathways. To identify compounds capable of counteracting the effects of PR on nucleocytoplasmic transport, we developed a nucleocytoplasmic transport assay and screened several commercially available compound libraries, totaling 2714 compounds. In addition to restoring nucleocytoplasmic transport efficiencies, hits from the screen also counteract the cytotoxic effects of PR. Selected hits were subsequently tested for their ability to rescue another C9ALS/FTD phenotype—persistent DNA double strand breakage. Overall, we found that DPRs disrupt multiple nucleocytoplasmic transport pathways and we identified small molecules that counteract these effects—resulting in increased viability of PR-expressing cells and decreased DNA damage markers in patient-derived motor neurons. Several HDAC inhibitors were validated as hits, supporting previous studies that show that HDAC inhibitors confer therapeutic effects in neurodegenerative models.
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Affiliation(s)
- Melina Ramic
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Nadja S. Andrade
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Matthew J. Rybin
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Rustam Esanov
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Claes Wahlestedt
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th St., Miami, FL 33136, USA;
| | - Zane Zeier
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
- Correspondence: ; Tel.: +1-305-243-1367
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24
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Ito D. Promise of Nucleic Acid Therapeutics for Amyotrophic Lateral Sclerosis. Ann Neurol 2021; 91:13-20. [PMID: 34704267 DOI: 10.1002/ana.26259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 12/14/2022]
Abstract
Nucleic acid therapeutics have been attracting attention as novel drug discovery modalities for intractable diseases, including amyotrophic lateral sclerosis. This review provides an overview of the current status and prospects of antisense oligonucleotide treatment for amyotrophic lateral sclerosis. Recently, the results of a phase I/II study using the antisense oligonucleotides Tofersen to treat familial amyotrophic lateral sclerosis with superoxide dismutase 1 mutation have been reported. Intrathecal Tofersen administration resulted in a 36% reduction in superoxide dismutase 1 level in the cerebrospinal fluid. Another report described 2 patients with mutant superoxide dismutase 1 treated with an adeno-associated virus encoding a microRNA targeting superoxide dismutase 1. The first patient, who possessed the fast progressive mutant A5V, received a single intrathecal infusion. Although the patient died of respiratory arrest 16 months after treatment, autopsy findings showed a reduction of >90% in superoxide dismutase 1 level in the spinal cord. Clinical trials on antisense oligonucleotide therapies targeting other major amyotrophic lateral sclerosis-causative genes, fused in sarcoma and chromosome 9 open reading frame 72, are ongoing. To attenuate the pathology of TDP-43, strategies targeting regulators of TDP-43 (ataxin 2) and proteins downstream of TDP-43 (stathmin 2) by antisense oligonucleotides are being developed. The advent of nucleic acid therapeutics has enabled to specifically attack the molecules in the amyotrophic lateral sclerosis pathological cascade, expanding the options for therapeutic targets. ANN NEUROL 2021.
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Affiliation(s)
- Daisuke Ito
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
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25
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Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol 2021; 22:589-607. [PMID: 34140671 PMCID: PMC9612635 DOI: 10.1038/s41580-021-00382-6] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 02/05/2023]
Abstract
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Chase P Kelley
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
- Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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26
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The porphyrin TMPyP4 inhibits elongation during the noncanonical translation of the FTLD/ALS-associated GGGGCC repeat in the C9orf72 gene. J Biol Chem 2021; 297:101120. [PMID: 34450161 PMCID: PMC8446798 DOI: 10.1016/j.jbc.2021.101120] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 08/15/2021] [Accepted: 08/23/2021] [Indexed: 12/24/2022] Open
Abstract
GGGGCC (G4C2) repeat expansion in the C9orf72 gene has been shown to cause frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Dipeptide repeat proteins produced through repeat-associated non-AUG (RAN) translation are recognized as potential drivers for neurodegeneration. Therefore, selective inhibition of RAN translation could be a therapeutic avenue to treat these neurodegenerative diseases. It was previously known that the porphyrin TMPyP4 binds to G4C2 repeat RNA. However, the consequences of this interaction have not been well characterized. Here, we confirmed that TMPyP4 inhibits C9orf72 G4C2 repeat translation in cellular and in in vitro translation systems. An artificial insertion of an AUG codon failed to cancel the translation inhibition, suggesting that TMPyP4 acts downstream of non-AUG translation initiation. Polysome profiling assays also revealed polysome retention on G4C2 repeat RNA, along with inhibition of translation, indicating that elongating ribosomes stall on G4C2 repeat RNA. Urea-resistant interaction between G4C2 repeat RNA and TMPyP4 likely contributes to this ribosome stalling and thus to selective inhibition of RAN translation. Taken together, our data reveal a novel mode of action of TMPyP4 as an inhibitor of G4C2 repeat translation elongation.
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27
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Semmelink MFW, Steen A, Veenhoff LM. Measuring and Interpreting Nuclear Transport in Neurodegenerative Disease-The Example of C9orf72 ALS. Int J Mol Sci 2021; 22:9217. [PMID: 34502125 PMCID: PMC8431710 DOI: 10.3390/ijms22179217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/13/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Transport from and into the nucleus is essential to all eukaryotic life and occurs through the nuclear pore complex (NPC). There are a multitude of data supporting a role for nuclear transport in neurodegenerative diseases, but actual transport assays in disease models have provided diverse outcomes. In this review, we summarize how nuclear transport works, which transport assays are available, and what matters complicate the interpretation of their results. Taking a specific type of ALS caused by mutations in C9orf72 as an example, we illustrate these complications, and discuss how the current data do not firmly answer whether the kinetics of nucleocytoplasmic transport are altered. Answering this open question has far-reaching implications, because a positive answer would imply that widespread mislocalization of proteins occurs, far beyond the reported mislocalization of transport reporters, and specific proteins such as FUS, or TDP43, and thus presents a challenge for future research.
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Affiliation(s)
| | | | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (M.F.W.S.); (A.S.)
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28
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Leskelä S, Hoffmann D, Rostalski H, Huber N, Wittrahm R, Hartikainen P, Korhonen V, Leinonen V, Hiltunen M, Solje E, Remes AM, Haapasalo A. FTLD Patient-Derived Fibroblasts Show Defective Mitochondrial Function and Accumulation of p62. Mol Neurobiol 2021; 58:5438-5458. [PMID: 34328616 PMCID: PMC8599259 DOI: 10.1007/s12035-021-02475-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/25/2021] [Indexed: 11/25/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and neuropathologically heterogeneous group of neurodegenerative syndromes, leading to progressive cognitive dysfunction and frontal and temporal atrophy. C9orf72 hexanucleotide repeat expansion (C9-HRE) is the most common genetic cause of FTLD, but pathogenic mechanisms underlying FTLD are not fully understood. Here, we compared cellular features and functional properties, especially related to protein degradation pathways and mitochondrial function, of FTLD patient–derived skin fibroblasts from C9-HRE carriers and non-carriers and healthy donors. Fibroblasts from C9-HRE carriers were found to produce RNA foci, but no dipeptide repeat proteins, and they showed unchanged levels of C9orf72 mRNA transcripts. The main protein degradation pathways, the ubiquitin–proteasome system and autophagy, did not show alterations between the fibroblasts from C9-HRE-carrying and non-carrying FTLD patients and compared to healthy controls. An increase in the number and size of p62-positive puncta was evident in fibroblasts from both C9-HRE carriers and non-carriers. In addition, several parameters of mitochondrial function, namely, basal and maximal respiration and respiration linked to ATP production, were significantly reduced in the FTLD patient–derived fibroblasts from both C9-HRE carriers and non-carriers. Our findings suggest that FTLD patient–derived fibroblasts, regardless of whether they carry the C9-HRE expansion, show unchanged proteasomal and autophagic function, but significantly impaired mitochondrial function and increased accumulation of p62 when compared to control fibroblasts. These findings suggest the possibility of utilizing FTLD patient–derived fibroblasts as a platform for biomarker discovery and testing of drugs targeted to specific cellular functions, such as mitochondrial respiration.
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Affiliation(s)
- Stina Leskelä
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Dorit Hoffmann
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Hannah Rostalski
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Nadine Huber
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Rebekka Wittrahm
- Institute of Biomedicine, University of Eastern Finland, Yliopistonranta 1E, 70211, Kuopio, Finland
| | - Päivi Hartikainen
- Neuro Center, Neurology, Kuopio University Hospital, 70029, Kuopio, Finland
| | - Ville Korhonen
- Neuro Center, Neurosurgery, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurosurgery, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Ville Leinonen
- Neuro Center, Neurosurgery, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurosurgery, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Yliopistonranta 1E, 70211, Kuopio, Finland
| | - Eino Solje
- Neuro Center, Neurology, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurology, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Anne M Remes
- Unit of Clinical Neuroscience, Neurology, University of Oulu, P.O. Box 8000, 90014, Oulu, Finland
- MRC Oulu, Oulu University Hospital, P.O. Box 8000, 90014, Oulu, Finland
| | - Annakaisa Haapasalo
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland.
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29
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Nanoscopic investigation of C9orf72 poly-GA oligomers on nuclear membrane disruption by a photoinducible platform. Commun Chem 2021; 4:111. [PMID: 36697556 PMCID: PMC9814621 DOI: 10.1038/s42004-021-00547-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/01/2021] [Indexed: 01/28/2023] Open
Abstract
Glycine-alanine dipeptide repeats (GA DPRs) translated from the mutated C9orf72 gene have recently been correlated with amyotrophic lateral sclerosis (ALS). While GA DPRs aggregates have been suggested as amyloid, the biophysical features and cytotoxicity of GA DPRs oligomers has not been explored due to its unstable nature. In this study, we develop a photoinducible platform based on methoxynitrobenzene chemistry to enrich GA DPRs that allows monitoring the oligomerization process of GA DPRs in cells. By applying advanced microscopies, we examined the GA DPRs oligomerization process nanoscopically in a time-dependent manner. We provided direct evidences to demonstrate GA DPRs oligomers rather than nanofibrils disrupt nuclear membrane. Moreover, we found GA DPRs hamper nucleocytoplasmic transport in cells and cause cytosolic retention of TAR DNA-binding protein 43 in cortical neurons. Our results highlight the toxicity of GA DPRs oligomers, which is a key step toward elucidating the pathological roles of C9orf72 DPRs.
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30
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Frottin F, Pérez-Berlanga M, Hartl FU, Hipp MS. Multiple pathways of toxicity induced by C9orf72 dipeptide repeat aggregates and G 4C 2 RNA in a cellular model. eLife 2021; 10:62718. [PMID: 34161229 PMCID: PMC8221807 DOI: 10.7554/elife.62718] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 06/08/2021] [Indexed: 12/05/2022] Open
Abstract
The most frequent genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia is a G4C2 repeat expansion in the C9orf72 gene. This expansion gives rise to translation of aggregating dipeptide repeat (DPR) proteins, including poly-GA as the most abundant species. However, gain of toxic function effects have been attributed to either the DPRs or the pathological G4C2 RNA. Here, we analyzed in a cellular model the relative toxicity of DPRs and RNA. Cytoplasmic poly-GA aggregates, generated in the absence of G4C2 RNA, interfered with nucleocytoplasmic protein transport, but had little effect on cell viability. In contrast, nuclear poly-GA was more toxic, impairing nucleolar protein quality control and protein biosynthesis. Production of the G4C2 RNA strongly reduced viability independent of DPR translation and caused pronounced inhibition of nuclear mRNA export and protein biogenesis. Thus, while the toxic effects of G4C2 RNA predominate in the cellular model used, DPRs exert additive effects that may contribute to pathology.
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Affiliation(s)
- Frédéric Frottin
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Manuela Pérez-Berlanga
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - F Ulrich Hartl
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Mark S Hipp
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.,School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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31
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Creekmore BC, Chang YW, Lee EB. The Cryo-EM Effect: Structural Biology of Neurodegenerative Disease Proteostasis Factors. J Neuropathol Exp Neurol 2021; 80:494-513. [PMID: 33860329 PMCID: PMC8177850 DOI: 10.1093/jnen/nlab029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative diseases are characterized by the accumulation of misfolded proteins. This protein aggregation suggests that abnormal proteostasis contributes to aging-related neurodegeneration. A better fundamental understanding of proteins that regulate proteostasis may provide insight into the pathophysiology of neurodegenerative disease and may perhaps reveal novel therapeutic opportunities. The 26S proteasome is the key effector of the ubiquitin-proteasome system responsible for degrading polyubiquitinated proteins. However, additional factors, such as valosin-containing protein (VCP/p97/Cdc48) and C9orf72, play a role in regulation and trafficking of substrates through the normal proteostasis systems of a cell. Nonhuman AAA+ ATPases, such as the disaggregase Hsp104, also provide insights into the biochemical processes that regulate protein aggregation. X-ray crystallography and cryo-electron microscopy (cryo-EM) structures not bound to substrate have provided meaningful information about the 26S proteasome, VCP, and Hsp104. However, recent cryo-EM structures bound to substrate have provided new information about the function and mechanism of these proteostasis factors. Cryo-EM and cryo-electron tomography data combined with biochemical data have also increased the understanding of C9orf72 and its role in maintaining proteostasis. These structural insights provide a foundation for understanding proteostasis mechanisms with near-atomic resolution upon which insights can be gleaned regarding the pathophysiology of neurodegenerative diseases.
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Affiliation(s)
- Benjamin C Creekmore
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi-Wei Chang
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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UBQLN2-HSP70 axis reduces poly-Gly-Ala aggregates and alleviates behavioral defects in the C9ORF72 animal model. Neuron 2021; 109:1949-1962.e6. [PMID: 33991504 DOI: 10.1016/j.neuron.2021.04.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/09/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022]
Abstract
Expansion of a hexanucleotide repeat GGGGCC (G4C2) in the intron of the C9ORF72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9-ALS/FTD). Transcripts carrying G4C2 repeat expansions generate neurotoxic dipeptide repeat (DPR) proteins, including poly-Gly-Ala (poly-GA), which tends to form protein aggregates. Here, we demonstrate that UBQLN2, another ALS/FTD risk factor, is recruited to reduce poly-GA aggregates and alleviate poly-GA-induced neurotoxicity. UBQLN2 could recognize HSP70 ubiquitination, which facilitates the UBQLN2-HSP70-GA complex formation and promotes poly-GA degradation. ALS/FTD-related UBQLN2 mutants fail to bind HSP70 and clear poly-GA aggregates. Disruption of the interaction between UBQLN2 and HSP70 inhibits poly-GA aggregation in C9-ALS/FTD iPSC-derived neurons. Finally, enhancing HSP70 by the chemical compound 17AAG at the adult stage mitigates behavioral defects in poly-GA animals. Our findings suggest a critical role of the UBQLN2-HSP70 axis in protein aggregate clearance in C9-ALS/FTD.
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Expression of C9orf72 hexanucleotide repeat expansion leads to formation of RNA foci and dipeptide repeat proteins but does not influence autophagy or proteasomal function in neuronal cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119021. [PMID: 33775797 DOI: 10.1016/j.bbamcr.2021.119021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/06/2021] [Accepted: 03/22/2021] [Indexed: 12/22/2022]
Abstract
C9orf72 hexanucleotide repeat expansion (HRE) is the major genetic cause underpinning frontotemporal lobar degeneration (FLTD) and amyotrophic lateral sclerosis (ALS). C9orf72 HRE-associated pathogenesis involves both loss-of-function, through reduced C9orf72 levels, and gain-of-function mechanisms, including formation of RNA foci and generation of dipeptide repeat (DPR) proteins. In addition, dysfunctional protein degradation pathways, i.e. autophagy and ubiquitin-proteasome system (UPS), are suggested. Our aim was to study the gain-of-function mechanisms in the context of the function of protein degradation pathways as well as the regulation of the DPR proteins through these pathways. To this end, we expressed the pathological HRE in neuronal N2a cells and mouse primary cortical neurons. Protein degradation pathways were modulated to induce or block autophagy or to inhibit UPS. In addition, proteasomal activity was assessed. The C9orf72 HRE-expressing N2a cells and neurons were confirmed to produce RNA foci and DPR proteins, predominantly the Poly-GP proteins. However, the presence of these pathological hallmarks did not result in alterations in autophagy or proteasomal activity in either of the studied cell types. In N2a cells, Poly-GP proteins appeared in soluble forms and Lactacystin-mediated UPS inhibition increased their levels, indicating proteasomal regulation. Similar effects were not observed in cortical neurons, where the Poly-GP proteins formed also higher molecular weight forms. These results suggest a cell type-specific morphology and regulation of the DPR proteins. Further studies in other model systems may shed additional light onto the effects of the C9orf72 HRE on cellular protein degradation pathways and the regulation of the DPR protein levels.
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Schmitz A, Pinheiro Marques J, Oertig I, Maharjan N, Saxena S. Emerging Perspectives on Dipeptide Repeat Proteins in C9ORF72 ALS/FTD. Front Cell Neurosci 2021; 15:637548. [PMID: 33679328 PMCID: PMC7930069 DOI: 10.3389/fncel.2021.637548] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide expansion in the chromosome 9 open reading frame 72 gene (C9ORF72). This hexanucleotide expansion consists of GGGGCC (G4C2) repeats that have been implicated to lead to three main modes of disease pathology: loss of function of the C9ORF72 protein, the generation of RNA foci, and the production of dipeptide repeat proteins (DPRs) through repeat-associated non-AUG (RAN) translation. Five different DPRs are currently known to be formed: glycine-alanine (GA) and glycine-arginine (GR) from the sense strand, proline-alanine (PA), and proline-arginine (PR) from the antisense strand, and glycine-proline (GP) from both strands. The exact contribution of each DPR to disease pathology is currently under intense scrutiny and is still poorly understood. However, recent advances in both neuropathological and cellular studies have provided us with clues enabling us to better understand the effect of individual DPRs on disease pathogenesis. In this review, we compile the current knowledge of specific DPR involvement on disease development and highlight recent advances, such as the impact of arginine-rich DPRs on nucleolar protein quality control, the correlation of poly-GR with neurodegeneration, and the possible involvement of chimeric DPR species. Further, we discuss recent findings regarding the mechanisms of RAN translation, its modulators, and other promising therapeutic options.
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Affiliation(s)
- Alexander Schmitz
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - João Pinheiro Marques
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Irina Oertig
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Niran Maharjan
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Smita Saxena
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
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Aladesuyi Arogundade O, Nguyen S, Leung R, Wainio D, Rodriguez M, Ravits J. Nucleolar stress in C9orf72 and sporadic ALS spinal motor neurons precedes TDP-43 mislocalization. Acta Neuropathol Commun 2021; 9:26. [PMID: 33588953 PMCID: PMC7885352 DOI: 10.1186/s40478-021-01125-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 01/30/2021] [Indexed: 12/11/2022] Open
Abstract
Nucleolar stress has been implicated in the pathology and disease pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) from repeat expansions of GGGGCC in C9orf72 (C9-ALS/FTLD) but not in sporadic ALS (SALS). Previously we reported that antisense RNA transcripts are unique in C9-ALS because of their nucleolar localization in spinal motor neurons and correlation with TDP-43 mislocalization, the hallmark proteinopathy of ALS and FTLD. Here we report our further studies of 11 SALS, 11 C9-ALS and 11 control spinal cords. We find that nucleolar stress manifests specifically as shrinkage in nucleoli of C9-ALS spinal motor neurons. Nucleolar size reduction is greatest in similarly sized alpha motor neurons from C9-ALS cases and results are not skewed by the number of surviving neurons from each ALS spinal cord. Surprisingly, nucleolar shrinkage occurs before main pathological hallmarks-TDP-43 mislocalization or antisense RNA foci-appear and this suggest that nucleolar stress can precede pathology in C9-ALS, findings previously identified in C9-FTLD using sense RNA foci and dipeptide repeat proteins as pathological markers. Importantly, these observations are also seen in SALS motor neurons and thus nucleolar stress appears to be a significant and probably upstream problem in sporadic disease.
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Affiliation(s)
| | - Sandra Nguyen
- University of California, San Diego, La Jolla, CA, USA
| | - Ringo Leung
- University of California, San Diego, La Jolla, CA, USA
| | | | | | - John Ravits
- University of California, San Diego, La Jolla, CA, USA.
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Ghasemi M, Keyhanian K, Douthwright C. Glial Cell Dysfunction in C9orf72-Related Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Cells 2021; 10:cells10020249. [PMID: 33525344 PMCID: PMC7912327 DOI: 10.3390/cells10020249] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 12/17/2022] Open
Abstract
Since the discovery of the chromosome 9 open reading frame 72 (C9orf72) repeat expansion mutation in 2011 as the most common genetic abnormality in amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease) and frontotemporal dementia (FTD), progress in understanding the signaling pathways related to this mutation can only be described as intriguing. Two major theories have been suggested-(i) loss of function or haploinsufficiency and (ii) toxic gain of function from either C9orf72 repeat RNA or dipeptide repeat proteins (DPRs) generated from repeat-associated non-ATG (RAN) translation. Each theory has provided various signaling pathways that potentially participate in the disease progression. Dysregulation of the immune system, particularly glial cell dysfunction (mainly microglia and astrocytes), is demonstrated to play a pivotal role in both loss and gain of function theories of C9orf72 pathogenesis. In this review, we discuss the pathogenic roles of glial cells in C9orf72 ALS/FTD as evidenced by pre-clinical and clinical studies showing the presence of gliosis in C9orf72 ALS/FTD, pathologic hallmarks in glial cells, including TAR DNA-binding protein 43 (TDP-43) and p62 aggregates, and toxicity of C9orf72 glial cells. A better understanding of these pathways can provide new insights into the development of therapies targeting glial cell abnormalities in C9orf72 ALS/FTD.
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Affiliation(s)
- Mehdi Ghasemi
- Correspondence: ; Tel.: +1-774-441-7726; Fax: +1-508-856-4485
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37
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Riemslagh FW, van der Toorn EC, Verhagen RFM, Maas A, Bosman LWJ, Hukema RK, Willemsen R. Inducible expression of human C9ORF72 36x G 4C 2 hexanucleotide repeats is sufficient to cause RAN translation and rapid muscular atrophy in mice. Dis Model Mech 2021; 14:dmm.044842. [PMID: 33431483 PMCID: PMC7903916 DOI: 10.1242/dmm.044842] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 12/17/2020] [Indexed: 12/29/2022] Open
Abstract
The hexanucleotide G4C2 repeat expansion in the first intron of the C9ORF72 gene explains the majority of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) cases. Numerous studies have indicated the toxicity of dipeptide repeats (DPRs) which are produced via repeat-associated non-AUG (RAN) translation from the repeat expansion and accumulate in the brain of C9FTD/ALS patients. Mouse models expressing the human C9ORF72 repeat and/or DPRs show variable pathological, functional, and behavioral characteristics of FTD and ALS. Here, we report a new Tet-on inducible mouse model that expresses 36x pure G4C2 repeats with 100bp upstream and downstream human flanking regions. Brain specific expression causes the formation of sporadic sense DPRs aggregates upon 6 months dox induction but no apparent neurodegeneration. Expression in the rest of the body evokes abundant sense DPRs in multiple organs, leading to weight loss, neuromuscular junction disruption, myopathy, and a locomotor phenotype within the time frame of four weeks. We did not observe any RNA foci or pTDP-43 pathology. Accumulation of DPRs and the myopathy phenotype could be prevented when 36x G4C2 repeat expression was stopped after 1 week. After 2 weeks of expression, the phenotype could not be reversed, even though DPR levels were reduced. In conclusion, expression of 36x pure G4C2 repeats including 100bp human flanking regions is sufficient for RAN translation of sense DPRs and evokes a functional locomotor phenotype. Our inducible mouse model suggests early diagnosis and treatment are important for C9FTD/ALS patients.
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Affiliation(s)
- F W Riemslagh
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - E C van der Toorn
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R F M Verhagen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - A Maas
- Department of Cell Biology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - L W J Bosman
- Department of Neuroscience, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R K Hukema
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - R Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
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38
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Lee J, Park J, Kim JH, Lee G, Park TE, Yoon KJ, Kim YK, Lim C. LSM12-EPAC1 defines a neuroprotective pathway that sustains the nucleocytoplasmic RAN gradient. PLoS Biol 2020; 18:e3001002. [PMID: 33362237 PMCID: PMC7757817 DOI: 10.1371/journal.pbio.3001002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023] Open
Abstract
Nucleocytoplasmic transport (NCT) defects have been implicated in neurodegenerative diseases such as C9ORF72-associated amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Here, we identify a neuroprotective pathway of like-Sm protein 12 (LSM12) and exchange protein directly activated by cyclic AMP 1 (EPAC1) that sustains the nucleocytoplasmic RAN gradient and thereby suppresses NCT dysfunction by the C9ORF72-derived poly(glycine-arginine) protein. LSM12 depletion in human neuroblastoma cells aggravated poly(GR)-induced impairment of NCT and nuclear integrity while promoting the nuclear accumulation of poly(GR) granules. In fact, LSM12 posttranscriptionally up-regulated EPAC1 expression, whereas EPAC1 overexpression rescued the RAN gradient and NCT defects in LSM12-deleted cells. C9-ALS patient-derived neurons differentiated from induced pluripotent stem cells (C9-ALS iPSNs) displayed low expression of LSM12 and EPAC1. Lentiviral overexpression of LSM12 or EPAC1 indeed restored the RAN gradient, mitigated the pathogenic mislocalization of TDP-43, and suppressed caspase-3 activation for apoptosis in C9-ALS iPSNs. EPAC1 depletion biochemically dissociated RAN-importin β1 from the cytoplasmic nuclear pore complex, thereby dissipating the nucleocytoplasmic RAN gradient essential for NCT. These findings define the LSM12-EPAC1 pathway as an important suppressor of the NCT-related pathologies in C9-ALS/FTD. A post-transcriptional circuit comprising LSM12 and EPAC1 suppresses neurodegenerative pathologies in C9ORF72-associated amyotrophic lateral sclerosis by establishing the RAN gradient and sustaining nucleocytoplasmic transport.
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Affiliation(s)
- Jongbo Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jumin Park
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Ji-hyung Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Giwook Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Tae-Eun Park
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Ki-Jun Yoon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yoon Ki Kim
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul, Republic of Korea
- Division of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Chunghun Lim
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
- * E-mail:
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Gagliardi D, Costamagna G, Taiana M, Andreoli L, Biella F, Bersani M, Bresolin N, Comi GP, Corti S. Insights into disease mechanisms and potential therapeutics for C9orf72-related amyotrophic lateral sclerosis/frontotemporal dementia. Ageing Res Rev 2020; 64:101172. [PMID: 32971256 DOI: 10.1016/j.arr.2020.101172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022]
Abstract
In 2011, a hexanucleotide repeat expansion (HRE) in the noncoding region of C9orf72 was associated with the most frequent genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The main pathogenic mechanisms in C9-ALS/FTD are haploinsufficiency of the C9orf72 protein and gain of function toxicity from bidirectionally-transcribed repeat-containing RNAs and dipeptide repeat proteins (DPRs) resulting from non-canonical RNA translation. Additionally, abnormalities in different downstream cellular mechanisms, such as nucleocytoplasmic transport and autophagy, play a role in pathogenesis. Substantial research efforts using in vitro and in vivo models have provided valuable insights into the contribution of each mechanism in disease pathogenesis. However, conflicting evidence exists, and a unifying theory still lacks. Here, we provide an overview of the recently published literature on clinical, neuropathological and molecular features of C9-ALS/FTD. We highlight the supposed neuronal role of C9orf72 and the HRE pathogenic cascade, mainly focusing on the contribution of RNA foci and DPRs to neurodegeneration and discussing the several downstream mechanisms. We summarize the emerging biochemical and neuroimaging biomarkers, as well as the potential therapeutic approaches. Despite promising results, a specific disease-modifying treatment is still not available to date and greater insights into disease mechanisms may help in this direction.
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Affiliation(s)
- Delia Gagliardi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Gianluca Costamagna
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michela Taiana
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Luca Andreoli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Fabio Biella
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Margherita Bersani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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40
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He F, Flores BN, Krans A, Frazer M, Natla S, Niraula S, Adefioye O, Barmada SJ, Todd PK. The carboxyl termini of RAN translated GGGGCC nucleotide repeat expansions modulate toxicity in models of ALS/FTD. Acta Neuropathol Commun 2020; 8:122. [PMID: 32753055 PMCID: PMC7401224 DOI: 10.1186/s40478-020-01002-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
An intronic hexanucleotide repeat expansion in C9ORF72 causes familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This repeat is thought to elicit toxicity through RNA mediated protein sequestration and repeat-associated non-AUG (RAN) translation of dipeptide repeat proteins (DPRs). We generated a series of transgenic Drosophila models expressing GGGGCC (G4C2) repeats either inside of an artificial intron within a GFP reporter or within the 5' untranslated region (UTR) of GFP placed in different downstream reading frames. Expression of 484 intronic repeats elicited minimal alterations in eye morphology, viability, longevity, or larval crawling but did trigger RNA foci formation, consistent with prior reports. In contrast, insertion of repeats into the 5' UTR elicited differential toxicity that was dependent on the reading frame of GFP relative to the repeat. Greater toxicity correlated with a short and unstructured carboxyl terminus (C-terminus) in the glycine-arginine (GR) RAN protein reading frame. This change in C-terminal sequence triggered nuclear accumulation of all three RAN DPRs. A similar differential toxicity and dependence on the GR C-terminus was observed when repeats were expressed in rodent neurons. The presence of the native C-termini across all three reading frames was partly protective. Taken together, these findings suggest that C-terminal sequences outside of the repeat region may alter the behavior and toxicity of dipeptide repeat proteins derived from GGGGCC repeats.
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41
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Jafarinia H, van der Giessen E, Onck PR. Phase Separation of Toxic Dipeptide Repeat Proteins Related to C9orf72 ALS/FTD. Biophys J 2020; 119:843-851. [PMID: 32730793 DOI: 10.1016/j.bpj.2020.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/28/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022] Open
Abstract
The expansion mutation in the C9orf72 gene is the most common known genetic cause for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This mutation can produce five dipeptide repeat proteins (DPRs), of which three are known to be toxic: poly-PR, poly-GR, and poly-GA. The toxicity of poly-GA is attributed to its aggregation in the cytoplasm, whereas for poly-PR and poly-GR, several toxicity pathways have been proposed. The toxicity of the DPRs has been shown to depend on their length, but the underlying molecular mechanism of this length dependence is not well understood. To address the possible role of phase separation in DPR toxicity, a one-bead-per-amino-acid (1BPA) coarse-grained molecular dynamics model is used to study the single-molecule and phase-separation properties of the DPRs. We find a strong dependence of the phase-separation behavior on both DPR length and concentration, with longer DPRs having a higher propensity to phase separate and form condensed phases with higher concentrations. The critical lengths required for phase separation (25 for poly-PR and 50 for poly-GA) are comparable to the toxicity threshold limit of 30 repeats found for the expansion mutation in patient cells, suggesting that phase separation could play an important role in DPR toxicity.
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Affiliation(s)
- Hamidreza Jafarinia
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands.
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42
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Tang X, Toro A, T G S, Gao J, Chalk J, Oskarsson B, Zhang K. Divergence, Convergence, and Therapeutic Implications: A Cell Biology Perspective of C9ORF72-ALS/FTD. Mol Neurodegener 2020; 15:34. [PMID: 32513219 PMCID: PMC7282082 DOI: 10.1186/s13024-020-00383-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/26/2020] [Indexed: 12/12/2022] Open
Abstract
Ever since a GGGGCC hexanucleotide repeat expansion mutation in C9ORF72 was identified as the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), three competing but nonexclusive hypotheses to explain how this mutation causes diseases have been proposed and are still under debate. Recent studies in the field have tried to understand how the repeat expansion disrupts cellular physiology, which has suggested interesting convergence of these hypotheses on downstream, functional defects in cells, such as nucleocytoplasmic transport disruption, membrane-less organelle defects, and DNA damage. These studies have not only provided an integrated view of the disease mechanism but also revealed novel cell biology implicated in neurodegeneration. Furthermore, some of the discoveries have given rise to new ideas for therapeutic development. Here, we review the research progress on cellular pathophysiology of C9ORF72-mediated ALS and FTD and its therapeutic implication. We suggest that the repeat expansion drives pathogenesis through a combination of downstream defects, of which some can be therapeutic targets.
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Affiliation(s)
- Xiaoqiang Tang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Arturo Toro
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Sahana T G
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Junli Gao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Jessica Chalk
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Ke Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA. .,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, USA.
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Limanaqi F, Busceti CL, Biagioni F, Cantini F, Lenzi P, Fornai F. Cell-Clearing Systems Bridging Repeat Expansion Proteotoxicity and Neuromuscular Junction Alterations in ALS and SBMA. Int J Mol Sci 2020; 21:ijms21114021. [PMID: 32512809 PMCID: PMC7312203 DOI: 10.3390/ijms21114021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
The coordinated activities of autophagy and the ubiquitin proteasome system (UPS) are key to preventing the aggregation and toxicity of misfold-prone proteins which manifest in a number of neurodegenerative disorders. These include proteins which are encoded by genes containing nucleotide repeat expansions. In the present review we focus on the overlapping role of autophagy and the UPS in repeat expansion proteotoxicity associated with chromosome 9 open reading frame 72 (C9ORF72) and androgen receptor (AR) genes, which are implicated in two motor neuron disorders, amyotrophic lateral sclerosis (ALS) and spinal-bulbar muscular atrophy (SBMA), respectively. At baseline, both C9ORF72 and AR regulate autophagy, while their aberrantly-expanded isoforms may lead to a failure in both autophagy and the UPS, further promoting protein aggregation and toxicity within motor neurons and skeletal muscles. Besides proteotoxicity, autophagy and UPS alterations are also implicated in neuromuscular junction (NMJ) alterations, which occur early in both ALS and SBMA. In fact, autophagy and the UPS intermingle with endocytic/secretory pathways to regulate axonal homeostasis and neurotransmission by interacting with key proteins which operate at the NMJ, such as agrin, acetylcholine receptors (AChRs), and adrenergic beta2 receptors (B2-ARs). Thus, alterations of autophagy and the UPS configure as a common hallmark in both ALS and SBMA disease progression. The findings here discussed may contribute to disclosing overlapping molecular mechanisms which are associated with a failure in cell-clearing systems in ALS and SBMA.
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Affiliation(s)
- Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | | | - Francesca Biagioni
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
| | - Federica Cantini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Paola Lenzi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
- Correspondence:
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44
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Casterton RL, Hunt RJ, Fanto M. Pathomechanism Heterogeneity in the Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Disease Spectrum: Providing Focus Through the Lens of Autophagy. J Mol Biol 2020; 432:2692-2713. [PMID: 32119873 DOI: 10.1016/j.jmb.2020.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/15/2020] [Accepted: 02/17/2020] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) constitute aggressive neurodegenerative pathologies that lead to the progressive degeneration of upper and lower motor neurons and of neocortical areas, respectively. In the past decade, the identification of several genes that cause these disorders indicated that the two diseases overlap in a multifaceted spectrum of conditions. The autophagy-lysosome system has been identified as a main intersection for the onset and progression of neurodegeneration in ALS/FTD. Genetic evidence has revealed that several genes with a mechanistic role at different stages of the autophagy process are mutated in patients with ALS/FTD. Moreover, the three main proteins aggregating in ALS/FTD, including in sporadic cases, are also targeted by autophagy and affect this process. Here, we examine the varied dysfunctions and degrees of involvement of the autophagy-lysosome system that have been discovered in ALS/FTD. We argue that these findings shed light on the pathological mechanisms in the ALS/FTD spectrum and conclude that they have important consequences both for treatment options and for the basic biomolecular understanding of how this process intersects with RNA metabolism, the other major cellular process reported to be dysfunctional in part of the ALS/FTD spectrum.
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Affiliation(s)
- Rebecca L Casterton
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom
| | - Rachel J Hunt
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom
| | - Manolis Fanto
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom; Institut du Cerveau et de la Moelle épinière (ICM), 47, bd de l'hôpital, F-75013 Paris, France.
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45
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Andrade NS, Ramic M, Esanov R, Liu W, Rybin MJ, Gaidosh G, Abdallah A, Del’Olio S, Huff TC, Chee NT, Anatha S, Gendron TF, Wahlestedt C, Zhang Y, Benatar M, Mueller C, Zeier Z. Dipeptide repeat proteins inhibit homology-directed DNA double strand break repair in C9ORF72 ALS/FTD. Mol Neurodegener 2020; 15:13. [PMID: 32093728 PMCID: PMC7041170 DOI: 10.1186/s13024-020-00365-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 02/13/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The C9ORF72 hexanucleotide repeat expansion is the most common known genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two fatal age-related neurodegenerative diseases. The C9ORF72 expansion encodes five dipeptide repeat proteins (DPRs) that are produced through a non-canonical translation mechanism. Among the DPRs, proline-arginine (PR), glycine-arginine (GR), and glycine-alanine (GA) are the most neurotoxic and increase the frequency of DNA double strand breaks (DSBs). While the accumulation of these genotoxic lesions is increasingly recognized as a feature of disease, the mechanism(s) of DPR-mediated DNA damage are ill-defined and the effect of DPRs on the efficiency of each DNA DSB repair pathways has not been previously evaluated. METHODS AND RESULTS Using DNA DSB repair assays, we evaluated the efficiency of specific repair pathways, and found that PR, GR and GA decrease the efficiency of non-homologous end joining (NHEJ), single strand annealing (SSA), and microhomology-mediated end joining (MMEJ), but not homologous recombination (HR). We found that PR inhibits DNA DSB repair, in part, by binding to the nucleolar protein nucleophosmin (NPM1). Depletion of NPM1 inhibited NHEJ and SSA, suggesting that NPM1 loss-of-function in PR expressing cells leads to impediments of both non-homologous and homology-directed DNA DSB repair pathways. By deleting NPM1 sub-cellular localization signals, we found that PR binds NPM1 regardless of the cellular compartment to which NPM1 was directed. Deletion of the NPM1 acidic loop motif, known to engage other arginine-rich proteins, abrogated PR and NPM1 binding. Using confocal and super-resolution immunofluorescence microscopy, we found that levels of RAD52, a component of the SSA repair machinery, were significantly increased iPSC neurons relative to isogenic controls in which the C9ORF72 expansion had been deleted using CRISPR/Cas9 genome editing. Western analysis of post-mortem brain tissues confirmed that RAD52 immunoreactivity is significantly increased in C9ALS/FTD samples as compared to controls. CONCLUSIONS Collectively, we characterized the inhibitory effects of DPRs on key DNA DSB repair pathways, identified NPM1 as a facilitator of DNA repair that is inhibited by PR, and revealed deficits in homology-directed DNA DSB repair pathways as a novel feature of C9ORF72-related disease.
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Affiliation(s)
- Nadja S. Andrade
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Melina Ramic
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Rustam Esanov
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Wenjun Liu
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, 1600 NW 10th Ave, Miami, FL 33136 USA
| | - Mathew J. Rybin
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Gabriel Gaidosh
- John P Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136 USA
- Sylvester Comprehensive Cancer Center, Biomedical Research Building, 1501 NW 10th Avenue, Miami, FL 33136 USA
| | - Abbas Abdallah
- Department of Neurology, University of Massachusetts Medical School, Worchester, MA USA
| | - Samuel Del’Olio
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Tyler C. Huff
- John P Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136 USA
- Dr. John T Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, 1601 NW 12th Ave, Miami, FL. 33136 USA
| | - Nancy T. Chee
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Sadhana Anatha
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Tania F. Gendron
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224 USA
| | - Claes Wahlestedt
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
| | - Yanbin Zhang
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, 1600 NW 10th Ave, Miami, FL 33136 USA
| | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, 115 NW 14th St.,, Miami, FL 33136 USA
| | - Christian Mueller
- Department of Neurology, University of Massachusetts Medical School, Worchester, MA USA
- Department of Pediatrics and Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA USA
| | - Zane Zeier
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Biomedical Research Building Room 413, Florida, Miami 33136 USA
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Boivin M, Pfister V, Gaucherot A, Ruffenach F, Negroni L, Sellier C, Charlet-Berguerand N. Reduced autophagy upon C9ORF72 loss synergizes with dipeptide repeat protein toxicity in G4C2 repeat expansion disorders. EMBO J 2020; 39:e100574. [PMID: 31930538 PMCID: PMC7024836 DOI: 10.15252/embj.2018100574] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022] Open
Abstract
Expansion of G4C2 repeats within the C9ORF72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Such repeats lead to decreased expression of the autophagy regulator C9ORF72 protein. Furthermore, sense and antisense repeats are translated into toxic dipeptide repeat (DPR) proteins. It is unclear how these repeats are translated, and in which way their translation and the reduced expression of C9ORF72 modulate repeat toxicity. Here, we found that sense and antisense repeats are translated upon initiation at canonical AUG or near‐cognate start codons, resulting in polyGA‐, polyPG‐, and to a lesser degree polyGR‐DPR proteins. However, accumulation of these proteins is prevented by autophagy. Importantly, reduced C9ORF72 levels lead to suboptimal autophagy, thereby impairing clearance of DPR proteins and causing their toxic accumulation, ultimately resulting in neuronal cell death. Of clinical importance, pharmacological compounds activating autophagy can prevent neuronal cell death caused by DPR proteins accumulation. These results suggest the existence of a double‐hit pathogenic mechanism in ALS/FTD, whereby reduced expression of C9ORF72 synergizes with DPR protein accumulation and toxicity.
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Affiliation(s)
- Manon Boivin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Véronique Pfister
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Angeline Gaucherot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Frank Ruffenach
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Luc Negroni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Université de Strasbourg, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
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47
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Djajadikerta A, Keshri S, Pavel M, Prestil R, Ryan L, Rubinsztein DC. Autophagy Induction as a Therapeutic Strategy for Neurodegenerative Diseases. J Mol Biol 2019; 432:2799-2821. [PMID: 31887286 DOI: 10.1016/j.jmb.2019.12.035] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/28/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022]
Abstract
Autophagy is a major, conserved cellular pathway by which cells deliver cytoplasmic contents to lysosomes for degradation. Genetic studies have revealed extensive links between autophagy and neurodegenerative disease, and disruptions to autophagy may contribute to pathology in some cases. Autophagy degrades many of the toxic, aggregate-prone proteins responsible for such diseases, including mutant huntingtin (mHTT), alpha-synuclein (α-syn), tau, and others, raising the possibility that autophagy upregulation may help to reduce levels of toxic protein species, and thereby alleviate disease. This review examines autophagy induction as a potential therapy in several neurodegenerative diseases-Alzheimer's disease, Parkinson's disease, polyglutamine diseases, and amyotrophic lateral sclerosis (ALS). Evidence in cells and in vivo demonstrates promising results in many disease models, in which autophagy upregulation is able to reduce the levels of toxic proteins, ameliorate signs of disease, and delay disease progression. However, the effective therapeutic use of autophagy induction requires detailed knowledge of how the disease affects the autophagy-lysosome pathway, as activating autophagy when the pathway cannot go to completion (e.g., when lysosomal degradation is impaired) may instead exacerbate disease in some cases. Investigating the interactions between autophagy and disease pathogenesis is thus a critical area for further research.
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Affiliation(s)
- Alvin Djajadikerta
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Swati Keshri
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Mariana Pavel
- Department of Immunology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, 700115, Romania
| | - Ryan Prestil
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Laura Ryan
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK.
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48
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Yuva-Aydemir Y, Almeida S, Krishnan G, Gendron TF, Gao FB. Transcription elongation factor AFF2/FMR2 regulates expression of expanded GGGGCC repeat-containing C9ORF72 allele in ALS/FTD. Nat Commun 2019; 10:5466. [PMID: 31784536 PMCID: PMC6884579 DOI: 10.1038/s41467-019-13477-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 11/11/2019] [Indexed: 12/18/2022] Open
Abstract
Expanded GGGGCC (G4C2) repeats in C9ORF72 cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How RNAs containing expanded G4C2 repeats are transcribed in human neurons is largely unknown. Here we describe a Drosophila model in which poly(GR) expression in adult neurons causes axonal and locomotor defects and premature death without apparent TDP-43 pathology. In an unbiased genetic screen, partial loss of Lilliputian (Lilli) activity strongly suppresses poly(GR) toxicity by specifically downregulating the transcription of GC-rich sequences in Drosophila. Knockout of AFF2/FMR2 (one of four mammalian homologues of Lilli) with CRISPR-Cas9 decreases the expression of the mutant C9ORF72 allele containing expanded G4C2 repeats and the levels of repeat RNA foci and dipeptide repeat proteins in cortical neurons derived from induced pluripotent stem cells of C9ORF72 patients, resulting in rescue of axonal degeneration and TDP-43 pathology. Thus, AFF2/FMR2 regulates the transcription and toxicity of expanded G4C2 repeats in human C9ORF72-ALS/FTD neurons.
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Affiliation(s)
- Yeliz Yuva-Aydemir
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
| | - Gopinath Krishnan
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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49
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Nussbacher JK, Tabet R, Yeo GW, Lagier-Tourenne C. Disruption of RNA Metabolism in Neurological Diseases and Emerging Therapeutic Interventions. Neuron 2019; 102:294-320. [PMID: 30998900 DOI: 10.1016/j.neuron.2019.03.014] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 01/24/2019] [Accepted: 03/12/2019] [Indexed: 02/06/2023]
Abstract
RNA binding proteins are critical to the maintenance of the transcriptome via controlled regulation of RNA processing and transport. Alterations of these proteins impact multiple steps of the RNA life cycle resulting in various molecular phenotypes such as aberrant RNA splicing, transport, and stability. Disruption of RNA binding proteins and widespread RNA processing defects are increasingly recognized as critical determinants of neurological diseases. Here, we describe distinct mechanisms by which the homeostasis of RNA binding proteins is compromised in neurological disorders through their reduced expression level, increased propensity to aggregate or sequestration by abnormal RNAs. These mechanisms all converge toward altered neuronal function highlighting the susceptibility of neurons to deleterious changes in RNA expression and the central role of RNA binding proteins in preserving neuronal integrity. Emerging therapeutic approaches to mitigate or reverse alterations of RNA binding proteins in neurological diseases are discussed.
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Affiliation(s)
- Julia K Nussbacher
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, University of California, San Diego, La Jolla, CA, USA
| | - Ricardos Tabet
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute of Harvard University and MIT, Cambridge, MA 02142, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, UCSD Stem Cell Program, University of California, San Diego, La Jolla, CA, USA.
| | - Clotilde Lagier-Tourenne
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute of Harvard University and MIT, Cambridge, MA 02142, USA.
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50
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Lai JD, Ichida JK. C9ORF72 protein function and immune dysregulation in amyotrophic lateral sclerosis. Neurosci Lett 2019; 713:134523. [DOI: 10.1016/j.neulet.2019.134523] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 09/24/2019] [Accepted: 09/26/2019] [Indexed: 12/13/2022]
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