Klebsiella pneumoniae (KP) infections represent a significant global health challenge, characterized by severe inflammatory sequelae and escalating antimicrobial resistance. This comprehensive review elucidates the complex interplay between macrophages and KP, encompassing pathogen recognition mechanisms, macrophage activation states, cellular death pathways, and emerging immunotherapeutic strategies. We critically analyze current literature on macrophage pattern recognition receptor engagement with KP-associated molecular patterns. The review examines the spectrum of macrophage responses to KP infection, including classical M1 polarization and the newly described M(Kp) phenotype, alongside metabolic reprogramming events such as glycolytic enhancement and immune responsive gene 1 (IRG1)-itaconate upregulation. We systematically evaluate macrophage fate decisions in response to KP, including autophagy, apoptosis, pyroptosis, and necroptosis. Furthermore, we provide a critical assessment of potential future therapeutic modalities. Given the limitations of current treatment paradigms, elucidating macrophage-KP interactions is imperative. Insights gained from this analysis may inform the development of novel immunomodulatory approaches to augment conventional antimicrobial therapies, potentially transforming the clinical management of KP infections.

Oxidative stress and chronic inflammation are important drivers in the pathogenesis and progression of many chronic diseases, such as cancers of the breast, kidney, lung, and others, autoimmune diseases (rheumatoid arthritis), cardiovascular diseases (hypertension, atherosclerosis, arrhythmia), neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, Huntington's disease), mental disorders (depression, schizophrenia, bipolar disorder), gastrointestinal disorders (inflammatory bowel disease, colorectal cancer), and other disorders. With the increasing demand for less toxic and more tolerable therapies, flavonoids have the potential to effectively modulate the responsiveness to conventional therapy and radiotherapy. Flavonoids are polyphenolic compounds found in fruits, vegetables, grains, and plant-derived beverages. Six of the twelve structurally different flavonoid subgroups are of dietary significance and include anthocyanidins (e.g. pelargonidin, cyanidin), flavan-3-ols (e.g. epicatechin, epigallocatechin), flavonols (e.g. quercetin, kaempferol), flavones (e.g. luteolin, baicalein), flavanones (e.g. hesperetin, naringenin), and isoflavones (daidzein, genistein). The health benefits of flavonoids are related to their structural characteristics, such as the number and position of hydroxyl groups and the presence of C2=C3 double bonds, which predetermine their ability to chelate metal ions, terminate ROS (e.g. hydroxyl radicals formed by the Fenton reaction), and interact with biological targets to trigger a biological response. Based on these structural characteristics, flavonoids can exert both antioxidant or prooxidant properties, modulate the activity of ROS-scavenging enzymes and the expression and activation of proinflammatory cytokines (e.g., interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α)), induce apoptosis and autophagy, and target key signaling pathways, such as the nuclear factor erythroid 2-related factor 2 (Nrf2) and Bcl-2 family of proteins. This review aims to briefly discuss the mutually interconnected aspects of oxidative and inflammatory mechanisms, such as lipid peroxidation, protein oxidation, DNA damage, and the mechanism and resolution of inflammation. The major part of this article discusses the role of flavonoids in alleviating oxidative stress and inflammation, two common components of many human diseases. The results of epidemiological studies on flavonoids are also presented.

Exosomes are involved in intercellular communication and regulation of the inflammatory microenvironment. In a previous study, we demonstrated that fresh ginseng exosomes (GEs) alleviated inflammatory bowel disease. However, the precise mechanism by which GEs activate the immune system and subsequently inhibit the formation of intestinal inflammatory microenvironment remains unknown.

Herein, we investigated the effects of GEs on autophagy, macrophage polarisation, intestinal inflammation, and the epithelial barrier by means of transcriptome sequencing, network pharmacology, transmission electron microscopy, immunoblotting, flow cytometry and small molecule inhibitors.

GEs significantly activated autophagy and M2-like macrophage polarisation, which could be blocked by the autophagy inhibitor 3-methyladenine. In the co-culture system of macrophages and intestinal epithelial cells, macrophages treated with GEs secreted more interleukin-10 (IL-10) and significantly reduced Nitric oxide (NO) levels in intestinal epithelial cells in vitro. Furthermore, GEs acted directly on intestinal epithelial cells through the IKK/IкB/NF-кB signalling pathway to reduce inflammation and restore the intestinal barrier. Orally administered GEs could restore disrupted colonic barriers, alleviate inflammatory bowel responses, and regulate the polarisation of intestinal macrophages in vivo.

In summary, GEs may be a potential treatment for inflammatory bowel disease, and targeting autophagy and macrophage polarisation may help alleviate intestinal inflammation.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis, which poses a significant threat to human health. Lipoproteins are predominantly found in the M. tuberculosis cell wall during infection of the invading host. The cell wall interacts closely with the host cell in direct contact. The M. tuberculosis genome encodes at least 99 lipoproteins with diverse functions, including ABC transport, cell wall metabolism, adhesion, cell invasion, and signal transduction, among others. Different lipoproteins play important roles in bacterial survival, infection of host cells, vaccine development, and gene regulation for drug targeting. Although only a subset of these lipoproteins has been functionally investigated, most of them require further study. This review summarises the progress of research related to the synthesis of M. tuberculosis lipoproteins and their involvement in the functions of material transport, immune response, virulence mechanism, vaccine development, signalling, enzyme, and drug regulation.

Juvenile idiopathic arthritis (JIA) can lead to synovial inflammation. JIA is a chronic autoimmune inflammatory condition that primarily affects children. It is recognized as the most prevalent form of arthritis in the pediatric population and is associated with significant impairment and disability. As an inflammatory regulator, Nod-like receptor 3 (NLRP3) has been implicated in various autoimmune diseases. However, the specific mechanism by which NLRP3 impacts the progress of JIA remains unclear. Therefore, we conducted this study to investigate the specific mechanism of NLRP3 on the progress of synovial inflammation in juvenile collagen-induced arthritis (CIA). The CIA model was established using Sprague‒Dawley (SD) rats aged 2-3 weeks. In this study, we investigated the potential role of NLRP3 on JIA by regulating the NLRP3-NF-κB axis in CIA rats. To verify the effect of NLRP3 on JIA, the expression of NLRP3 was knocked down or overexpressed by an adeno-associated virus injected into the knee joint of the CIA rats. In this study, we observed that NLRP3 plays an important role in the development of juvenile CIA, and knocking down NLRP3 inhibited inflammation and alleviated synovium inflammation. We also demonstrated that the expression of NLRP3 was increased in synovial tissue, and NLRP3 could upregulate the NF-κB signal pathway and influence inflammation. Moreover, we also found that increases in the expression of NLRP3 impairs autophagy capacity and increases activation of the pyroptosis pathway in the synovium of the juvenile CIA rats. The results demonstrated that NLRP3 interferes with synovial inflammation in juvenile CIA. These results provide new insight into the mechanism by which NLRP3 impacts the development of JIA and suggest that targeting the NLRP3 inflammasome may represent a promising therapeutic strategy for managing JIA.

Acyl CoA binding protein encoded by diazepam binding inhibitor (ACBP/DBI) is a tissue hormone that stimulates lipo-anabolic responses and inhibits autophagy, thus contributing to aging and age-related diseases. Protein expression profiling of ACBP/DBI was performed on mouse tissues to identify organs in which this major tissue hormone is expressed. Transcriptomic and proteomic data bases corroborated a high level of human-mouse interspecies conservation of ACBP/DBI expression in different organs. Single-cell RNA-seq data confirmed that ACBP/DBI was strongly expressed by parenchymatous cells from specific human and mouse organs (e.g., kidney, large intestine, liver, lung) as well as by myeloid or glial cells from other organs (e.g., adipose tissue, brain, eye) following a pattern that was conserved among the two species. We identified a panel of 44 mRNAs that are strongly co-expressed with ACBP/DBI mRNA in normal and malignant human and normal mouse tissues. Of note, 22 (50%) of these co-expressed mRNAs encode proteins localized at mitochondria, and mRNAs with metabolism-related functions are strongly overrepresented (66%). Systematic data mining was performed to identify transcription factors that regulate ACBP/DBI expression in human and mouse. Several transcription factors, including growth response 1 (EGR1), E2F Transcription Factor 1 (E2F1, which interacts with retinoblastoma, RB) and transformation-related protein 53 (TRP53, best known as p53), which are endowed with oncosuppressive effects, consistently repress ACBP/DBI expression as well as its co-expressed mRNAs across multiple datasets, suggesting a mechanistic basis for a coregulation network. Furthermore, we identified multiple transcription factors that transactivate ACBP/DBI gene expression together with its coregulation network. Altogether, this study indicates the existence of conserved mechanisms determining the expression of ACBP/DBI in specific cell types of the mammalian organism.

Autophagy, a regulator of inflammation, has been implicated in various central nervous system pathologies. Despite this, the role and mechanisms of autophagy in lipopolysaccharide (LPS)-induced neuroinflammation are not clear. This study investigated whether autophagy can play a neuroprotective role in LPS-induced neuroinflammation.

Primary microglial cells and male C57BL/6 J mice were treated with LPS, autophagy inhibitors (3-methyladenine, 3-MA), or autophagy activators (rapamycin). Cell viability, NF-κB pathway activation, pro-inflammatory cytokine expression, M1 polarization, autophagy markers, and neuronal damage were evaluated via various techniques including CCK-8 assay, Western blot analysis, ELISA, immunohistochemistry, and histological staining.

LPS (1 μg/mL) effectively inhibited cell viability, stimulated the expression of IκB-α and NF-κB, and simultaneously suppressed autophagy protein expression. The pro-inflammatory cytokines IL-1β and IL-6 showed a significant increase. Contrary to the effect of 3-MA, the rapamycin treatment inhibited the polarization of microglia cells to the M1 type in the various groups of microglia cells after LPS stimulation. This was evidenced by decreased expression of cytokines IL-1β, IL-6, and CD86, and increased expression of Arg-1, IL-10, and CD206. In vivo experiments found that mice with injections of LPS and 3-MA in the lateral ventricle showed significantly increased expression of IκB-α and NF-κB in brain tissues, elevated levels of pro-inflammatory cytokines, decreased autophagy levels, and increased necrotic neurons. There was increased aggregation of microglia cells and increased neuronophagocytosis. Conversely, mice injected with rapamycin showed enhanced neuronal cell autophagy, decreased expression of pro-inflammatory cytokines and apoptosis, and reduced neuronophagocytosis.

Enhancing autophagy can effectively mitigate LPS-induced neuroinflammation by inhibiting microglial M1 polarization and neuronophagocytosis, thereby protecting neuronal integrity. These findings suggest potential therapeutic strategies targeting autophagy in neuroinflammatory conditions.

Autophagy plays a crucial role in the physiopathological mechanisms of diseases by regulating cellular functions and maintaining cellular homeostasis, which has garnered extensive attention from researchers worldwide. The holistic regulation and bidirectional regulation effects of acupuncture can modulate cellular autophagy, promoting or restoring the homeostasis of the body's internal environment to achieve therapeutic outcomes. This paper systematically reviews the research progress on the use of acupuncture for treating various diseases via the autophagy pathway, summarizes signal pathways related to acupuncture regulating autophagy, and analyzes the deficiencies present in the existing research. The review results indicate that the mechanism of action of acupuncture on autophagy dysfunction is reflected in the changes in LC3, Beclin1, p53, and autophagy-associated (ATG) protein expression, and regulates signaling pathways and key proteins or genes. The regulatory effect of acupuncture on autophagy capacity is bidirectional: it inhibits the abnormal activation of autophagy to prevent exacerbation of injury and reduce apoptosis, while also activating or enhancing autophagy to promote the elimination of inflammation and reduce oxidative stress. Further analysis suggests that the mechanisms of acupuncture regulating autophagy are insufficiently explored. Future research should prioritize the development of more appropriate animal models, analyzing the accuracy of relevant pathways and the specificity of indicators, exploring the synergistic effects among targets and signaling pathways, clarifying the regulatory mechanisms of acupuncture at various stages of autophagy, and evaluating the efficacy of acupuncture in autophagy modulating. This paper offers valuable insights into the regulation of autophagy by acupuncture.

Porcine circovirus type 2 (PCV2) is an important pathogen that leads to great economic losses to the swine industry. Paeoniflorin (PF), a novel plant extract, has been reported to have antiviral properties. However, the role of paeoniflorin in regulating PCV2 replication remains unclear. Here, we used the CCK8 assay to demonstrate that PF within safe concentrations (0-275 mM) significantly inhibits PCV2 replication in a dose-dependent manner in porcine kidney cells. Subsequently, comparative transcriptome and functional verification revealed that PF probably inherits PCV2 replication via targeting AKT/mTOR signaling. Further experimental data show that the AKT/mTOR signaling pathway is highly relevant to autophagy. Thus, experimental data from Western blot, qPCR, and the indirect immunofluorescence test indicate that PF inhibits PCV2 replication by inhibiting autophagy by targeting the AKT/mTOR signaling pathway. Together, our results provide insight into the mechanism of paeoniflorin in regulating PCV2 replication and offer new ideas for the treatment of PCV2 infection in pigs.

Dry eye disease (DED) stands as a prominent ocular condition of global prevalence, emerging as a growing concern within public health. However, the underlying mechanisms involved in its pathogenesis remain largely unknown. In recent years, with the development of metabolomics, numerous studies have reported alterations in ocular surface metabolism in DED and offered fresh perspectives on the development of DED.

The metabolic changes of the ocular surface of DED patients are closely intertwined with the cellular metabolism process and immune inflammation changes. This article expounds upon the correlation between ocular surface metabolism and immune inflammation alterations in DED in terms of glycolysis, lipid metabolism, amino acid metabolism, cellular signaling pathways, and immune inflammation regulation.

The alterations in ocular surface metabolism of patients with dry eye are closely associated with their inflammatory status. Our work contributes novel insights into the pathogenesis of dry eye diseases and offers innovative molecular targets for diagnosing, detecting, and managing DED patients.

Interleukin-27 (IL-27) is a cytokine that is reported to be highly expressed in the peripheral blood of patients with pulmonary tuberculosis (PTB). IL-27-mediated signaling pathways, which exhibit anti- Mycobacterium tuberculosis (Mtb) properties, have also been demonstrated in macrophages infected with Mtb. However, the exact mechanism remains unclear. This study aimed to clarify the potential molecular mechanisms through which IL-27 enhances macrophage resistance to Mtb infection. Both normal and PTB patients provided bronchoalveolar lavage fluid (BALF). Peripheral blood mononuclear cells (PBMCs) were isolated from healthy individuals and stimulated with 50 ng/mL macrophage-colony stimulating factor (M-CSF) to obtain monocyte-derived macrophages (MDMs). Using 100 ng/mL phorbol 12-myristate 13-acetate (PMA), THP-1 cells were induced to differentiate into THP-1-derived macrophage-like cells (TDMs). Both MDMs and TDMs were subsequently infected with the Mtb strain H37Rv and treated with 50 ng/mL IL-27 prior to infection. The damage and inflammation of macrophages were examined using flow cytometry, enzyme-linked immunosorbent assay (ELISA), and Western blotting. Patients with PTB had elevated levels of IL-27 in their BALF. Preconditioning with IL-27 was shown to reduce H37Rv-induced MDMs and TDMs apoptosis while also decreasing the levels of Cleaved Caspase-3, Bax and the proinflammatory cytokines TNF-α, IL-1β, and IL-6, promoting the expression of Bcl-2 and the anti-inflammatory factors IL-10 and IL-4. Silencing of the IL-27 receptor IL-27Ra increased macrophage damage and inflammation triggered by H37Rv. Mechanistically, IL-27 activates autophagy by inhibiting TLR4/NF-κB signaling and activating the PI3K/AKT signaling pathway, thereby inhibiting H37Rv-induced macrophage apoptosis and the inflammatory response. Our study suggests that IL-27 alleviates H37Rv-induced macrophage injury and the inflammatory response by activating autophagy and that IL-27 may be a new target for the treatment of PTB.

Autophagy is a crucial immune defense mechanism that controls the survival and pathogenesis of M. tb by maintaining cell physiology during stress and pathogen attack. The E3-Ub ligases (PRKN, SMURF1, and NEDD4) and autophagy receptors (SQSTM1, TAX1BP1, CALCOCO2, OPTN, and NBR1) play key roles in this process. Galectins (LGALSs), which bind to sugars and are involved in identifying damaged cell membranes caused by intracellular pathogens such as M. tb, are essential. These include LGALS3, LGALS8, and LGALS9, which respond to endomembrane damage and regulate endomembrane damage caused by toxic chemicals, protein aggregates, and intracellular pathogens, including M. tb. They also activate selective autophagy and de novo endolysosome biogenesis. LGALS3, LGALS9, and LGALS8 interact with various components to activate autophagy and repair damage, while CGAS-STING1 plays a critical role in providing immunity against M. tb by activating selective autophagy and producing type I IFNs with antimycobacterial functions. STING1 activates cGAMP-dependent autophagy which provides immunity against various pathogens. Additionally, cytoplasmic surveillance pathways activated by ds-DNA, such as inflammasomes mediated by NLRP3 and AIM2 complexes, control M. tb. Modulation of E3-Ub ligases with small regulatory molecules of LGALSs and TRIM proteins could be a novel host-based therapeutic approach for controlling TB.

While moderately activated microglia in Alzheimer's disease (AD) are pivotal in clearing amyloid beta (Aβ), hyperactivated microglia perpetuate neuroinflammation. Prior investigations reported that the elimination of ~80% of microglia through inhibition of the colony-stimulating factor 1 receptor (CSF1R) during the advanced stage of neuroinflammation in 5xFamilial AD (5xFAD) mice mitigates synapse loss and neurodegeneration. Furthermore, prolonged CSF1R inhibition diminished the development of parenchymal plaques. Nonetheless, the effects of short-term CSF1R inhibition during the early stages of neuroinflammation on residual microglia are unknown. Therefore, we investigated the effects of 10-day CSF1R inhibition using PLX5622 in three-month-old female 5xFAD mice, a stage characterized by the onset of neuroinflammation and minimal Aβ plaques. We observed ~65% microglia depletion in the hippocampus and cerebral cortex. The leftover microglia displayed a noninflammatory phenotype with reduced NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome complexes. Moreover, plaque-associated microglia were reduced with diminished Clec7a expression. Additionally, phosphorylated S6 ribosomal protein and the protein sequestosome 1 analysis suggested reduced mechanistic targets of rapamycin (mTOR) signaling and autophagy in microglia and neurons within the hippocampus and cerebral cortex. Biochemical assays validated the inhibition of NLRP3 inflammasome activation, decreased mTOR signaling in the hippocampus and cerebral cortex, and enhanced autophagy in the hippocampus. However, short-term CSF1R inhibition did not influence Aβ plaques, soluble Aβ-42 levels, astrocyte hypertrophy, or hippocampal neurogenesis. Thus, short-term CSF1R inhibition during the early stages of neuroinflammation in 5xFAD mice promotes the retention of homeostatic microglia with diminished inflammasome activation and mTOR signaling, alongside increased autophagy.

Ammonia fertilizer, primarily composed of ammonium chloride, is widely used in pond fish farming throughout Asia. Despite the belief that it possesses antiviral properties, the underlying mechanisms remain unclear. Ammonium chloride (NH4Cl) has been demonstrated to act as a potent inhibitor of autophagy, which is used by many fish viruses to promote their proliferation during infection. It was therefore hypothesized that the antiviral effect of ammonia fertilizers was likely due to the inhibition of autophagy in viruses. The present study sought to evaluate the antiviral effect of NH4Cl in a model of several fish cells and zebrafish. The findings demonstrated that the administration of NH4Cl after viral infection inhibited the proliferation of a variety of fish viruses, encompassing both DNA and RNA viruses. Further studies have indicated that NH4Cl obstructed autophagy-dependent virus proliferation of spring viremia of carp virus (SVCV) by inhibiting autophagic flux. The molecular mechanism revealed that SVCV contributed to the polyubiquitination of interferon regulatory factor 3 (IRF3) and promoted the degradation of IRF3 through cargo receptor sequestosome 1 (SQSTM1/p62)-mediated selective autophagy. However, NH4Cl was observed to inhibit SVCV-mediated selective autophagy of IRF3, thereby facilitating the production of interferon. Furthermore, the SVCV N protein was of critical importance in this process. Nevertheless, NH4Cl impeded this degradation process by inhibiting the autophagy pathway. The study found that NH4Cl was highly efficacious in controlling fish virus infection both in vivo and in vitro. It can therefore be concluded that the antiviral effect of ammonia fertilizers was, at least in part, due to the inhibition of viral autophagy.

Dihydro-resveratrol (DHR), a polyphenol derivative, that has been demonstrated to suppress inflammation-mediated injury. However, it is still unknown whether it has anti-neuroinflammatory and neuroprotective effects, and a therapeutic action in Alzheimer's disease (AD).

The anti-inflammatory and anti-Alzheimer's disease actions of dihydro-resveratrol were investigated using lipopolysaccharide (LPS) and AD mice models, and primary microglial cells. The changes in behaviour in mice were detected by the Morris water maze test and open-field test. Flow cytometry assay, western blotting, immunofluorescence assays and co-immunoprecipitation were used to investigate the changes in the NLRP3 inflammasome activation and mitophagy.

In this study, in vivo observations indicated that the administration of dihydro-resveratrol (DHR) dramatically restored spatial learning, memory ability, autophagy and mitophagy, attenuated NLRP3 inflammasome activation, neuroinflammation and amyloid precursor protein pathology in LPS mice and AD mice. In addition, the inhibition of autophagy and mitophagy, or the activation of NLRP3 in vivo greatly abolished DHR-generated therapeutic efficacy on neuroinflammation, amyloid precursor protein pathology and cognitive loss. Further examination indicated that the application of DHR after the LPS and ATP exposure significantly inhibited the NLRP3 inflammasome activation, neuroinflammation and enhanced autophagic and mitophagic activation in microglia. Additionally, in vitro results show that DHR protects microglial cells against LPS and ATP-induced cytotoxicity by inhibiting NLRP3 inflammasome through activating Bnip3-dependent mitophagy and ULK phosphorylation.

In summary, these findings suggest that dihydro-resveratrol (DHR) possesses potent anti-neuroinflammatory property and can act as a potential therapeutic agent for the treatment of AD.

Human papillomavirus (HPV) infection is a worldwide reproductive system disease. Baofukang suppository, a traditional herbal preparation that includes curdione and borneol, has been reported to treat bacterial vaginosis (BV) and HPV infection in China. However, the therapeutic mechanism is still unknown. This study aims to explore the molecular mechanisms of curdione and borneol in treating HPV infection.

We conducted a retrospective cohort analysis of medical records from a single-center study involving 205 HPV patients, focusing on the correlation between HPV clearance and co-infection with other pathogens, confirming the efficacy of Baofukang suppository. Bioinformatics and network pharmacology approaches were employed to identify therapeutic targets of Baofukang suppository for BV/HPV co-infections. qRT-PCR, Western blot, immunofluorescence staining, and flow cytometry were utilized to validate the therapeutic targets of curdione and borneol, along with the associated immune molecular changes. Finally, the molecular mechanisms and therapeutic efficacy of curdione and borneol were confirmed in vivo using an LPS/TC-1 cervical orthotopic injection model.

Curdione and borneol selectively inhibit the secretion of interleukin-6 (IL-6) and interleukin-1β (IL-1β) by macrophages. The reduction in IL-6 and IL-1β levels effectively inhibits the expression of CD274 (Programmed death ligand 1, PD-L1) in infected epithelial cells by inhibiting STAT3 phosphorylation, thereby suppressing their immune evasion capabilities. Furthermore, curdione and borneol enhance the expression of tumor necrosis factor α (TNF-α) and caspase 1 (CASP1) in macrophages, as well as the expression of interleukin 12 (IL-12) and interleukin 23 (IL-23) in dendritic cells (DCs). The expression of these inflammatory factors effectively promotes the migration and differentiation of T cells to the site of infection, completing the clearance of infected epithelial cells.

The main components of Baofukang suppository, curdione and borneol, inhibit the progression of HPV infection and the occurrence of cervical cancer by modulating the communication between innate and adaptive immunity, promoting the recruitment and recognition of CD8+ T cells to eliminate HPV-infected epithelial cells.

Autophagy within macrophages serves as a vital mechanism for modulating inflammatory responses to central nervous system infections caused by Streptococcus suis in both humans and swine. However, the mechanism by which autophagy regulates inflammation during S. suis infection is unclear. This study investigated the mechanism by which autophagy serves as a defense against S. suis infection in mouse microglial cells (BV2). Initially, we examined how S. suis infection triggers the adenosine monophosphate-activated protein kinase (AMPK)/ mammalian target of rapamycin (mTOR) autophagic cascade and the nuclear factor kappa B (NF-κB) and, mitogen-activated protein kinase (MAPK) inflammatory signaling pathways using western blot within BV2 cells. We then demonstrated that treatment with autophagy inhibitors, inducers, and siRNA of autophagy genes changed the levels of C-C motif ligand 2 (CCL2), CCL3, CCL5, and tumor necrosis factor α (TNF-α), and p-p65, p-p38, p- c-Jun N-terminal kinase (JNK) and p-Extracellular signal-regulated kinase (ERK) activity within BV2 cells. We found that S. suis infection induced AMPK/mTOR autophagy pathway, NF-κB and MAPK pathway in BV2 cells. Further, Autophagy inhibits S. suis infection-induced NF-κB and MAPK signaling and subsequent inflammatory factors CCL2, CCL3, CCL5, and TNF-α. Collectively, these findings suggest that AMPK/mTOR-regulated autophagy has an inhibitory effect on pro-inflammatory cytokines and chemokines by regulating the NF-κB and MAPK pathways during S. suis infection.

Oral cancer is a highly malignant disease characterized by recurrence, metastasis, and poor prognosis. Autophagy, a catabolic process induced under stress conditions, has been shown to play a dual role in oral cancer development and therapy. Recent studies have identified that autophagy activation in oral epithelial cells suppresses cancer cell survival by inhibiting key pathways such as the mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK), while activating the adenosine monophosphate-activated protein kinase (AMPK) pathway. Inducing autophagy promotes degradation of eukaryotic initiation factor 4E, thus reducing metastasis and enhancing the efficacy of chemotherapy, radiotherapy, and immunotherapy. Furthermore, autophagy induction can modulate the tumor immune microenvironment and enhance antitumor immunity. This review comprehensively summarizes the relationship between autophagy and oral cancer, focusing on its mechanisms and therapeutic potential when combined with conventional treatments. While promising, the precise mechanisms and clinical applications of autophagy inducers in oral cancer therapy remain to be elucidated, offering new directions for future research to improve treatment outcomes and reduce recurrence.

Intestinal epithelial tight junctions (TJs), a dynamically regulated barrier structure composed of occludin and claudin family of proteins, mediate the interaction between the host and the external environment by allowing selective paracellular permeability between the luminal and serosal compartments of the intestine. TJs are highly dynamic structures and can undergo constant architectural remodeling in response to various external stimuli. This is mediated by an array of intracellular signaling pathways that alters TJ protein expression and localization. Dysfunctional regulation of TJ components compromising the barrier homeostasis is an important pathogenic factor for pathological conditions including inflammatory bowel disease (IBD). Previous studies have elucidated the significance of TJ barrier integrity and key regulatory mechanisms through various in vitro and in vivo models. In recent years, considerable efforts have been made to understand the crosstalk between various signaling pathways that regulate formation and disassembly of TJs. This review provides a comprehensive view on the novel mechanisms that regulate the TJ barrier and permeability. We discuss the latest evidence on how ion transport, cytoskeleton and extracellular matrix proteins, signaling pathways, and cell survival mechanism of autophagy regulate intestinal TJ barrier function. We also provide a perspective on the context-specific outcomes of the TJ barrier modulation. The knowledge on the diverse TJ barrier regulatory mechanisms will provide further insights on the relevance of the TJ barrier defects and potential target molecules/pathways for IBD.

Macrophage polarization is vital to mounting a host defense or repairing tissue in various liver diseases. Excessive activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome is related to the orchestration of inflammation and alcohol-associated liver disease (ALD) pathology. Rab GTPases play critical roles in regulating vesicular transport. In this study we investigated the role of Rab11b in ALD, aiming to identify effective therapeutic targets. Here, we first demonstrated a decreased expression of Rab11b in macrophages from ALD mice. Knockdown of Rab11b by macrophage-specific adeno-associated virus can alleviate alcohol induced liver inflammation, injury and steatosis. We found that LPS and alcohol stimulation promoted Rab11b transferring from the nucleus to the cytoplasm in bone marrow-derived macrophages (BMDM) cells. Rab11b specifically activated the NLRP3 inflammasome in BMDMs and RAW264.7 cells to induce M1 macrophage polarization. Rab11b overexpression in BMDMs inhibited autophagic flux, leading to the suppression of LC3B-mediated NLRP3 degradation. We conclude that impaired Rab11b could alleviate alcohol-induced liver injury via autophagy-mediated NLRP3 degradation.

Single-cell RNA-sequencing (scRNA-seq) is a powerful technique that can barcode individual cells and thus used to obtain a gene expression profile for every individual cell within a tissue. This makes scRNA-seq an excellent method for characterizing rare cell populations such as stem cells. We describe how scRNA-seq can be utilized to examine limbal epithelial stem cell population as well as investigate the contribution of autophagy to the function of limbal epithelial stem cells. To accomplish this, we used the Beclin1 heterozygous (Beclin1 het) mouse, a well-established model of autophagy deficiency. We provide a protocol that we developed for the isolation of viable, single-cell suspensions of limbal/corneal tissues, as well as the analysis of scRNA-seq data.

Mycobacterium tuberculosis (Mtb) complex, responsible for tuberculosis (TB) infection, continues to be a predominant global cause of mortality due to intricate host-pathogen interactions that affect disease progression. MicroRNAs (miRNAs), essential posttranscriptional regulators, have become pivotal modulators of these relationships. Recent findings indicate that miRNAs actively regulate immunological responses to Mtb complex by modulating autophagy, apoptosis, and immune cell activities. This has resulted in increased interest in miRNAs as prospective diagnostic indicators for TB, especially in differentiating active infection from latent or inactive stages. Variations in miRNA expression during Mtb infection indicate disease progression and offer insights into the immune response. Furthermore, miRNAs present potential as therapeutic targets in host-directed therapy (HDT) techniques for TB infection. This work examines the function of miRNAs in TB pathogenesis, with the objective of identifying particular miRNAs that regulate the immune response to the Mtb complex, evaluating their diagnostic value and exploring their therapeutic implications in host-directed therapy for TB infection. The objective is to enhance comprehension of how miRNAs can facilitate improved diagnosis and treatment of TB.

Persistent alloantigens derived from allograft tissues can be recognized by the host's alloreactive immune system. This process enables cognate B cells to differentiate into plasma cells, which secrete donor-specific antibodies that are key drivers of antibody-mediated allograft rejection. A subset of these plasma cells can survive for extended periods in a suitable survival niche and mature into long-lived plasma cells (LLPCs), which are a cellular component of humoral memory. The current understanding of LLPCs is limited due to their scarcity, heterogeneity, and absence of unique markers. However, accumulating evidence indicates that LLPCs, unlike conventional short-lived plasma cells, can respond to extrinsic signals from their survival niches and can resist cell death associated with intracellular stress through cell-intrinsic mechanisms. Notably, they are refractory to traditional immunosuppressants and B cell depletion therapies. This resistance, coupled with their longevity, may explain why current treatments targeting antibody-mediated rejection are often ineffective. This review offers insights into the biology of LLPCs and discusses ongoing therapeutic trials that target LLPCs in the context of antibody-mediated allograft rejection.

Many pathogens have evolved sophisticated strategies to evade autophagy, a crucial cellular defense mechanism that typically targets and degrades invading microorganisms. By subverting or inhibiting autophagy, these pathogens can create a more favorable environment for their replication and survival within the host. For instance, some bacteria secrete factors that block autophagosome formation, while others might escape from autophagosomes before degradation. These evasion tactics are critical for the pathogens' ability to establish and maintain infections. Understanding the mechanisms by which pathogens avoid autophagy is crucial for developing new therapeutic strategies, as enhancing autophagy could bolster the host's immune response and aid in the elimination of pathogenic bacteria. Francisella tularensis can manipulate host cell pathways to prevent its detection and destruction by autophagy, thereby enhancing its virulence. Given the potential for F. tularensis to be used as a bioterrorism agent due to its high infectivity and ability to cause severe disease, research into how this pathogen evades autophagy is of critical importance. By unraveling these mechanisms, new therapeutic approaches could be developed to enhance autophagic responses and strengthen host defense against this and other similarly evasive pathogens.

Chemical proteomics enables the global analysis of small molecule-protein interactions in native biological systems and has emerged as a versatile approach for ligand discovery. The range of small molecules explored by chemical proteomics has, however, remained limited. Here, we describe a diversity-oriented synthesis (DOS)-inspired library of stereochemically defined compounds bearing diazirine and alkyne units for UV light-induced covalent modification and click chemistry enrichment of interacting proteins, respectively. We find that these "photo-stereoprobes" interact in a stereoselective manner with hundreds of proteins from various structural and functional classes in human cells and demonstrate that these interactions can form the basis for high-throughput screening-compatible NanoBRET assays. Integrated phenotypic screening and chemical proteomics identified photo-stereoprobes that modulate autophagy by engaging the mitochondrial serine protease CLPP. Our findings show the utility of DOS-inspired photo-stereoprobes for expanding the ligandable proteome, furnishing target engagement assays, and facilitating the discovery and characterization of bioactive compounds in phenotypic screens.

Accumulating evidence indicates that the interaction between immune and skeletal systems is vital in bone homeostasis. However, the detailed mechanisms between macrophage polarization and osteogenic differentiation of mesenchymal stromal cells (bone marrow-derived stromal cells [BMSCs]) remain largely unknown. We observed enhanced macrophage infiltration along with bone formation in vivo, which showed a transition from early-stage M1 phenotype to later stage M2 phenotype, cells at the transitional stage expressed both M1 and M2 markers that actively participated in osteogenesis, which was mimicked by stimulating macrophages with lower inflammatory stimulus (compared with typical M1). Using conditioned medium (CM) from M0, typical M1, low-inflammatory M1 (M1semi), and M2 macrophages, it was found that BMSCs treated with M1semi CM showed significantly induced migration, osteogenic differentiation, and mineralization, compared with others. Along with the induced osteogenesis, the autophagy level was the highest in M1semi CM-treated BMSCs, which was responsible for BMSC migration and osteogenic differentiation, as autophagy interruption significantly abolished this effect. This study indicated that low-inflammatory macrophages could activate autophagy in BMSCs to improve osteogenesis.

Autophagy is a highly conserved biological process in eukaryotes, which degrades cellular misfolded proteins, damaged organelles and invasive pathogens in the lysosome-dependent manner. Autoimmune diseases caused by genetic elements, environments and aberrant immune responses severely impact patients' living quality and even threaten life. Recently, numerous studies have reported autophagy can regulate immune responses, and play an important role in autoimmune diseases. In this review, we summarised the features of autophagy and autophagy-related genes, enumerated some autophagy-related genes involved in autoimmune diseases, and further overviewed how to treat autoimmune diseases through targeting autophagy. Finally, we outlooked the prospect of relieving and curing autoimmune diseases by targeting autophagy pathway.

Autophagy captures damaged or dysfunctional proteins and organelles through the lysosomal pathway to achieve proper cellular homeostasis. Autophagy possesses distinct characteristics and is given recognized functions in numerous physiological and pathological conditions, such as cancer. Early stage cancer development can be stopped by autophagy. After tumor cells have successfully undergone transformation and progressed to a late stage, the autophagy-mediated system of dynamic degradation and recycling will support cancer cell growth and adaptation to various cellular stress responses while preserving energy homeostasis. In the present study, the dual function that autophagy plays in various oral cancer development contexts and stages, the existing arguments for and against autophagy, and the ways in which autophagy contributes to oral cancer modifications, such as carcinogenesis, drug resistance, invasion, metastasis and self-proliferation, are reviewed. Special attention is paid to the mechanisms and functions of autophagy in oral cancer processes, and the most recent findings on the application of certain conventional drugs or natural compounds as novel agents that modulate autophagy in oral cancer are discussed. Overall, further research is needed to determine the validity and reliability of autophagy promotion and inhibition while maximizing the difficult challenge of increasing cancer suppression to improve clinical outcomes.

Autophagy is an important cellular response against intracellular pathogens. However, some viruses have evolved mechanisms to hijack this defensive process to provide favorable conditions for virus replication in host cells. The porcine epidemic diarrhea virus (PEDV) has been shown to alter autophagy pathways; however, it is still unknown through which receptors PEDV induces autophagy in IPEC-J2 cells, whether autophagy facilitates PEDV replication, and which functional domains of PEDV proteins are primarily responsible for inducing autophagy. Here, we found that PEDV infection induces autophagy in host cells via distinct and uncoupled molecular pathways. RNA-seq technology was used to analyze the expression patterns of intracellular genes in PEDV-infected IPEC-J2 cells using transcriptomics. The results demonstrate that PEDV triggers autophagy via the cellular pathogen receptor TLR4 and the AKT-mTOR pathway. As evidenced by autophagosome detection, PEDV infection increases autophagosomes and light chain 3 (LC3)-II as well as downregulated AKT-mTOR phosphorylation. Our study revealed that the binding of the viral protein NSP61-2C (56-151aa) to TLR4 triggers autophagy and inactivates the AKT-mTOR pathway, both of which are critical for facilitating PEDV infection. Through screening and analysis, TLR4 was found to be a key gene involved in PEDV-induced autophagy. The screening of the key functional domains of NSP6 (56-151aa) for their ability to induce autophagy in IPEC-J2 cells provided a basis for the in-depth analysis of the pathogenic mechanism of PEDV infection-induced autophagy and promotion of self-replication and also provided an important target for the study of PEDV antiviral drugs. In conclusion, we elucidated that the PEDV infection of IPEC-J2 cells could induce autophagy and found that PEDV could use autophagy to promote its own replication.

Autophagy is a catabolic process that has been conserved throughout evolution, serving to degrade and recycle cellular components and damaged organelles. Autophagy is activated under various stress conditions, such as nutrient deprivation, viral infections, and genotoxic stress, and operates in conjunction with other stress response pathways to mitigate oxidative damage and maintain cellular homeostasis. One such pathway is the Nrf2-Keap1-ARE signaling axis, which functions as an intrinsic antioxidant defense mechanism and has been implicated in cancer chemoprevention, tumor progression, and drug resistance. Recent research has identified a link between impaired autophagy, mediated by the autophagy receptor protein p62, and the activation of the Nrf2 pathway. Specifically, p62 facilitates Keap1 degradation through selective autophagy, leading to the translocation of Nrf2 into the nucleus, where it transcriptionally activates downstream antioxidant enzyme expression, thus safeguarding cells from oxidative stress. Furthermore, Nrf2 regulates p62 transcription, so a positive feedback loop involving p62, Keap1, and Nrf2 is established, which amplifies the protective effects on cells. This paper aims to provide a comprehensive review of the roles of Nrf2 and autophagy in cancer progression, the regulatory interactions between the Nrf2 pathway and autophagy, and the potential applications of the Nrf2-autophagy signaling axis in cancer therapy.

Autophagy is a highly conserved degradative process that has been linked to various functions, including defending host cells against pathogens. Although the involvement of autophagy in porcine circovirus 2 (PCV2) infection has become apparent, it remains unclear whether selective autophagy plays a critical role in PCV2 restriction. Here we show that retinol-binding protein 4 (RBP4), an adipokine for retinol carrier, initiates the autophagic degradation of PCV2 ORF1 protein. PCV2 infection increases RBP4 protein levels through MAPK-eIF4E axis in living cells. Ectopic expression of RBP4 or recombinant RBP4 treatment promotes the degradation of ORF1 protein. Mechanistically, RBP4 activates TRAF6 to induce K63-linked ubiquitination of ORF1, leading to SQSTM1/p62-mediated selective autophagy for degradation. Consequently, RBP4 deficiency increases viral loads and exacerbates the pathogenicity of PCV2 in vivo. Collectively, these results identify RBP4 as a key host restriction factor of PCV2 and reveal a previously undescribed antiviral mechanism against PCV2 in infected cells.

Autophagy is a highly conserved cellular self-digestive process that underlies the maintenance of cellular homeostasis. Autophagy is classified into three types: macrophage, chaperone-mediated autophagy (CMA) and microphagy, which maintain cellular homeostasis through different mechanisms. Altered autophagy regulation affects the progression of various skin diseases, including psoriasis (PA), systemic lupus erythematosus (SLE), vitiligo, atopic dermatitis (AD), alopecia areata (AA) and systemic sclerosis (SSc). In this review, we review the existing literature focusing on three mechanisms of autophagy, namely macrophage, chaperone-mediated autophagy and microphagy, as well as the roles of autophagy in the above six dermatological disorders in order to aid in further studies in the future.

Staphylococcus aureus is an important bacterial pathogen that causes a wide variety of human diseases in community and hospital settings. S. aureus employs a diverse array of virulence factors, both surface-associated and secreted, to promote colonization, infection, and immune evasion. Over the past decade, a growing body of research has shown that S. aureus generates extracellular membrane vesicles (MVs) that package a variety of bacterial components, many of which are virulence factors. In this review, we summarize recent advances in our understanding of S. aureus MVs and highlight their biogenesis, cargo, and potential role in the pathogenesis of staphylococcal infections. Lastly, we present some emerging questions in the field.

Mycobacterium tuberculosis (Mtb) infects several lung macrophage populations, which have distinct abilities to restrict Mtb. What enables Mtb survival in certain macrophage populations is not well understood. Here we used transposon sequencing analysis of Mtb in wild-type and autophagy-deficient mouse macrophages lacking ATG5 or ATG7, and found that Mtb genes involved in phthiocerol dimycocerosate (PDIM) virulence lipid synthesis confer resistance to autophagy. Using ppsD mutant Mtb, we found that PDIM inhibits LC3-associated phagocytosis (LAP) by inhibiting phagosome recruitment of NADPH oxidase. In mice, PDIM protected Mtb from LAP and classical autophagy. During acute infection, PDIM was dispensable for Mtb survival in alveolar macrophages but required for survival in non-alveolar macrophages in an autophagy-dependent manner. During chronic infection, autophagy-deficient mice succumbed to infection with PDIM-deficient Mtb, with impairments in B-cell accumulation in lymphoid follicles. These findings demonstrate that PDIM contributes to Mtb virulence and immune evasion, revealing a contributory role for autophagy in B-cell responses.

Chinese1 is the predominant Toxoplasma gondii lineage in China, and significant phenotypic differences are observed within the lineage. WH3 and WH6 are two representative strains of Chinese 1, which exhibit divergent virulence and pathogenicity in mice. However, virulence determinants and their modulating mechanisms remain elusive. A global genome expression analysis of the WH3 and WH6 transcriptional profiles identified microneme secretory protein 6 (MIC6), which may be associated with the phenotypic difference observed in WH3. In the present study, the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome-editing technique was used to generate a T. gondii microneme secretory protein (TgMIC6) knockout in WH3. Wild-type mice and different mouse and human cell lines were infected with the WH3, WH3-Δmic6, and WH6 strains. The survival rate of mice, related cytokine levels in serum, and the proliferation of parasites were observed. These results suggested that TgMIC6 is an important effector molecule that determines the differential virulence of WH3 in vivo and in vitro. Furthermore, MIC6 may enhance WH3 virulence via inhibition of host cell autophagy and activation of key molecules in the epidermal growth factor receptor (EGFR)-Akt-mammalian target of rapamycin (mTOR) classical autophagy pathway. CD40L was cleared in vivo by i.p injection of CD40L monoclonal antibody, and it was found that the virulence of WH3-Δmic6 to mice was restored to a certain extent in the absence of CD40L. This study elucidates the virulence determinants and immune escape strategies of Toxoplasma gondii in China. Moreover, these data will aid the development of effective strategies for the prevention and control of toxoplasmosis.

Autophagy is a fundamental pillar of cellular resilience, indispensable for maintaining cellular health and vitality. It coordinates the meticulous breakdown of cytoplasmic macromolecules as a guardian of cell metabolism, genomic integrity, and survival. In the complex play of biological warfare, autophagy emerges as a firm defender, bravely confronting various pathogenic, infectious, and cancerous adversaries. Nevertheless, its role transcends mere defense, wielding both protective and harmful effects in the complex landscape of disease pathogenesis. From the onslaught of infectious outbreaks to the devious progression of chronic lifestyle disorders, autophagy emerges as a central protagonist, convolutedly shaping the trajectory of cellular health and disease progression. In this article, we embark on a journey into the complicated web of molecular and immunological mechanisms that govern autophagy's profound influence over disease. Our focus sharpens on dissecting the impact of various autophagy-associated proteins on the kaleidoscope of immune responses, spanning the spectrum from infectious outbreaks to chronic lifestyle ailments. Through this voyage of discovery, we unveil the vast potential of autophagy as a therapeutic linchpin, offering tantalizing prospects for targeted interventions and innovative treatment modalities that promise to transform the landscape of disease management.

The maintenance of intestinal homeostasis depends on a complex interaction between the immune system, intestinal epithelial barrier, and microbiota. Alteration in one of these components could lead to the development of inflammatory bowel diseases (IBD). Variants within the autophagy gene ATG16L1 have been implicated in susceptibility and severity of Crohn's disease (CD). Individuals carrying the risk ATG16L1 T300A variant have higher caspase 3-dependent degradation of ATG16L1 resulting in impaired autophagy and increased cellular stress. ATG16L1-deficiency induces enhanced IL-1β secretion in dendritic cells in response to bacterial infection. Infection of ATG16L1-deficient mice with a persistent strain of murine norovirus renders these mice highly susceptible to dextran sulfate sodium colitis. Moreover, persistent norovirus infection leads to intestinal virus specific CD8+ T cells responses. Both Toll-like receptor 7 (TLR7), which recognizes single-stranded RNA viruses, and ATG16L1, which facilitates the delivery of viral nucleic acids to the autolysosome endosome, are required for anti-viral immune responses.

However, the role of the enteric virome in IBD is still poorly understood. Here, we investigate the role of TLR7 and ATG16L1 in intestinal homeostasis and inflammation. At steady state, Tlr7-/- mice have a significant increase in large intestinal lamina propria (LP) granzyme B+ tissue-resident memory CD8+ T (TRM) cells compared to WT mice, reminiscent of persistent norovirus infection. Deletion of Atg16l1 in myeloid (Atg16l1ΔLyz2 ) or dendritic cells (Atg16l1ΔCd11c ) leads to a similar increase of LP TRM. Furthermore, Tlr7-/- and Atg16l1ΔCd11c mice were more susceptible to dextran sulfate sodium colitis with an increase in disease activity index, histoscore, and increased secretion of IFN-γ and TNF-α. Treatment of Atg16l1ΔCd11c mice with the TLR7 agonist Imiquimod attenuated colonic inflammation in these mice. Our data demonstrate that ATG16L1-deficiency in myeloid and dendritic cells leads to an increase in LP TRM and consequently to increased susceptibility to colitis by impairing the recognition of enteric viruses by TLR7.

In conclusion, the convergence of ATG16L1 and TLR7 signaling pathways plays an important role in the immune response to intestinal viruses. Our data suggest that activation of the TLR7 signaling pathway could be an attractive therapeutic target for CD patients with ATG16L1 risk variants.