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Pagel PS, Hang D, Freed JK, Crystal GJ. Advances in Cardiovascular Pharmacotherapy. II. Ivabradine, an Inhibitor of the Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel. J Cardiothorac Vasc Anesth 2025:S1053-0770(25)00247-2. [PMID: 40199701 DOI: 10.1053/j.jvca.2025.03.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2025] [Revised: 03/15/2025] [Accepted: 03/17/2025] [Indexed: 04/10/2025]
Abstract
Ivabradine selectively reduces heart rate by inhibiting the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel in the sinoatrial node. Unlike other medications that produce negative chronotropic effects [beta-blockers, calcium channel blockers], ivabradine does not affect systemic, pulmonary, and coronary hemodynamics. Despite several proof-of-concept clinical studies suggesting that ivabradine may exert anti-ischemic effects, two large randomized trials did not support its use in patients with chronic stable angina. Preliminary data also did not support the use of ivabradine in patients with acute ST-segment elevation myocardial infarction or acutely decompensated heart failure. However, ivabradine improved outcome in patients with heart failure with reduced ejection fraction (HFrEF), leading to its approval by the Food and Drug Administration, but the drug failed to do so in those with heart failure with preserved ejection fraction (HFpEF). Ivabradine may also be useful in cardiac electrophysiology disorders characterized by tachycardia (e.g., inappropriate sinus tachycardia, postural orthostatic tachycardia syndrome), but it has not yet gained wide acceptance for these indications. In this article, the authors briefly review the structure and function of the cardiac HCN channel; discuss the development and actions of drugs, including ivabradine, that modulate the channel's activity; describe in detail the potential clinical applications of ivabradine in patients with coronary artery disease, HFrEF and HFpEF, and cardiac electrophysiology; comment on the adverse effects of ivabradine therapy; and finally, consider the potential anesthetic implications of ivabradine in patients undergoing noncardiac and cardiac surgery.
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Affiliation(s)
- Paul S Pagel
- Department of Anesthesiology, the Medical College of Wisconsin, Milwaukee, WI.
| | - Dustin Hang
- Department of Anesthesiology, the Medical College of Wisconsin, Milwaukee, WI
| | - Julie K Freed
- Department of Anesthesiology, the Medical College of Wisconsin, Milwaukee, WI
| | - George J Crystal
- Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL
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Benndorf K, Enke U, Tewari D, Kusch J, Liu H, Sun H, Schmauder R, Sattler C. Subunit-specific conductance of single homomeric and heteromeric HCN pacemaker channels at femtosiemens resolution. Proc Natl Acad Sci U S A 2025; 122:e2422533122. [PMID: 39879240 PMCID: PMC11804576 DOI: 10.1073/pnas.2422533122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2024] [Accepted: 01/03/2025] [Indexed: 01/31/2025] Open
Abstract
In mammals, the four subunit isoforms HCN1-4 assemble to form functional homotetrameric and heterotetrameric hyperpolarization-activated cyclic nucleotide-modulated (HCN) ion channels. Despite the outstanding relevance of HCN channels for organisms, including generating electrical rhythmicity in cardiac pacemaker cells and diverse types of brain neurons, key channel properties are still elusive. In particular, the unitary conductance, γ, of HCN channels is highly controversial. We analyzed the unitary conductance at femtosiemens resolution of all four homotetrameric channels of the mouse, mHCN1-4. All conductance values are in the range of 1 pS which is exceptionally small compared to most other ion channels. Surprisingly, the conductance among the isoforms differs up to threefold (γmHCN2 = 1.54 pS > γmHCN1 = 0.84 pS > γmHCN3 = 0.54 pS ≈ γmHCN4 = 0.51 pS) though the residues in the two narrow parts of the pore, the selectivity filter and the inner gate, are conserved. Mutagenesis and all-atom molecular dynamics simulations demonstrate that the differences in the conductance are generated by different amounts of negative charges in the outer channel vestibule, which control ion accumulation. In line with these results, heterotetrameric channels exhibit intermediate unitary conductance values with respect to the homotetrameric channels. Our approach demonstrates how HCN channels can be functionally differentiated at the single-channel level, paving the way to target specific channels with selective drugs.
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Affiliation(s)
- Klaus Benndorf
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
| | - Uta Enke
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
| | - Debanjan Tewari
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
| | - Jana Kusch
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
| | - Haoran Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin13125, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin10623, Germany
| | - Han Sun
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin13125, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin10623, Germany
| | - Ralf Schmauder
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
| | - Christian Sattler
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena07740, Germany
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Burtscher V, Wang L, Cowgill J, Chen ZW, Edge C, Smith E, Chang Y, Delemotte L, Evers AS, Chanda B. A propofol binding site in the voltage sensor domain mediates inhibition of HCN1 channel activity. SCIENCE ADVANCES 2025; 11:eadr7427. [PMID: 39752505 PMCID: PMC11698089 DOI: 10.1126/sciadv.adr7427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Accepted: 12/02/2024] [Indexed: 01/06/2025]
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) ion channels are members of the cyclic nucleotide-binding family and are crucial for regulating cellular automaticity in many excitable cells. HCN channel activation contributes to pain perception, and propofol, a widely used anesthetic, acts as an analgesic by inhibiting the voltage-dependent activity of HCN channels. However, the molecular determinants of propofol action on HCN channels remain unknown. Here, we use a propofol-analog photoaffinity labeling reagent to identify propofol binding sites in the human HCN1 isoform. Mass spectrometry analyses combined with molecular dynamics simulations show that a binding pocket is formed by extracellularly facing residues in the S3 and S4 transmembrane segments in the resting voltage-sensor conformation. Mutations of residues within the putative binding pocket mitigate or eliminate voltage-dependent modulation of HCN1 currents by propofol. Together, these findings reveal a conformation-specific propofol binding site that underlies voltage-dependent inhibition of HCN currents and provides a framework for identifying highly specific modulators of HCN channel gating.
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Affiliation(s)
- Verena Burtscher
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Membrane Excitability Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lei Wang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
- Key Laboratory of Anesthesiology and Resuscitation (Huazhong University of Science and Technology), Ministry of Education, Wuhan 430022, China
| | - John Cowgill
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Zi-Wei Chen
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Christopher Edge
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Edward Smith
- Department of Biophysics, Imperial College of Science, Medicine and Technology, London SW7 2AZ, UK
| | - Yongchang Chang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Membrane Excitability Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Lucie Delemotte
- Department of Applied Physics, SciLifeLab, KTH Royal Institute of Technology, 17121 Solna, Sweden
| | - Alex S. Evers
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Baron Chanda
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Membrane Excitability Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
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Schapiro K, Rittenberg JD, Kenngott M, Marder E. I h block reveals separation of timescales in pyloric rhythm response to temperature changes in Cancer borealis. eLife 2024; 13:RP98844. [PMID: 39404608 PMCID: PMC11479588 DOI: 10.7554/elife.98844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024] Open
Abstract
Motor systems operate over a range of frequencies and relative timing (phase). We studied the role of the hyperpolarization-activated inward current (Ih) in regulating these features in the pyloric rhythm of the stomatogastric ganglion (STG) of the crab, Cancer borealis, as temperature was altered from 11°C to 21°C. Under control conditions, rhythm frequency increased monotonically with temperature, while the phases of the pyloric dilator (PD), lateral pyloric (LP), and pyloric (PY) neurons remained constant. Blocking Ih with cesium (Cs+) phase advanced PD offset, LP onset, and LP offset at 11°C, and the latter two further advanced as temperature increased. In Cs+ the frequency increase with temperature diminished and the Q10 of the frequency dropped from ~1.75 to ~1.35. Unexpectedly in Cs+, the frequency dynamics became non-monotonic during temperature transitions; frequency initially dropped as temperature increased, then rose once temperature stabilized, creating a characteristic 'jag'. Interestingly, these jags persisted during temperature transitions in Cs+ when the pacemaker was isolated by picrotoxin, although the temperature-induced change in frequency recovered to control levels. Overall, these data suggest that Ih plays an important role in maintaining smooth transitory responses and persistent frequency increases by different mechanisms in the pyloric circuitry during temperature fluctuations.
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Affiliation(s)
- Kyra Schapiro
- Biology Department, Brandeis UniversityWalthamUnited States
| | - JD Rittenberg
- Biology Department, Brandeis UniversityWalthamUnited States
| | - Max Kenngott
- Biology Department, Brandeis UniversityWalthamUnited States
| | - Eve Marder
- Biology Department, Brandeis UniversityWalthamUnited States
- Volen Center and Biology Department, Brandeis UniversityWalthamUnited States
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Schapiro KA, Rittenberg JD, Kenngott M, Marder E. I h Block Reveals Separation of Timescales in Pyloric Rhythm Response to Temperature Changes in Cancer borealis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.04.592541. [PMID: 38766157 PMCID: PMC11100622 DOI: 10.1101/2024.05.04.592541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Motor systems operate over a range of frequencies and relative timing (phase). We studied the contribution of the hyperpolarization-activated inward current (Ih) to frequency and phase in the pyloric rhythm of the stomatogastric ganglion (STG) of the crab, Cancer borealis as temperature was altered from 11°C to 21°C. Under control conditions, the frequency of the rhythm increased monotonically with temperature, while the phases of the pyloric dilator (PD), lateral pyloric (LP), and pyloric (PY) neurons remained constant. When we blocked Ih with cesium (Cs+) PD offset, LP onset, and LP offset were all phase advanced in Cs+ at 11°C, and the latter two further advanced as temperature increased. In Cs+ the steady state increase in pyloric frequency with temperature diminished and the Q10 of the pyloric frequency dropped from ~1.75 to ~1.35. Unexpectedly in Cs+, the frequency displayed non-monotonic dynamics during temperature transitions; the frequency initially dropped as temperature increased, then rose once temperature stabilized, creating a characteristic "jag". Interestingly, these jags were still present during temperature transitions in Cs+ when the pacemaker was isolated by picrotoxin, although the temperature-induced change in frequency recovered to control levels. Overall, these data suggest that Ih plays an important role in the ability of this circuit to produce smooth transitory responses and persistent frequency increases by different mechanisms during temperature fluctuations.
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Affiliation(s)
- Kyra A Schapiro
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454 USA
| | - J D Rittenberg
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454 USA
| | - Max Kenngott
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454 USA
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454 USA
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6
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Belmore L, Ahn T, Nguyen E, Lenz T. Acute Non-ST Segment Elevation Myocardial Infarction Following Intravenous Injection of Sublingual Suboxone. PREHOSP EMERG CARE 2024; 29:93-95. [PMID: 38975709 DOI: 10.1080/10903127.2024.2374999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 06/11/2024] [Accepted: 06/14/2024] [Indexed: 07/09/2024]
Abstract
Non-ST segment elevation myocardial infarction (NSTEMI) is a relatively unknown complication of injecting sublingual Suboxone (buprenorphine/naloxone). Buprenorphine/naloxone should be taken as a sublingual tablet or a buccal film and not injected, so its effects from this mode of administration are not well known. While the differential diagnosis for chest pain is very broad, many practitioners do not associate chest pain with the use of buprenorphine/naloxone. We recommend considering serial electrocardiograms (ECGs) and high-sensitivity troponins for a patient who presents with chest pain after buprenorphine/naloxone use.
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Affiliation(s)
- Lucas Belmore
- Touro University Osteopathic Medical School, Las Vegas, Nevada
| | - Timothy Ahn
- Touro University Osteopathic Medical School, Las Vegas, Nevada
| | - Eric Nguyen
- Touro University Osteopathic Medical School, Las Vegas, Nevada
| | - Timothy Lenz
- Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
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7
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Mehrotra D, Levenstein D, Duszkiewicz AJ, Carrasco SS, Booker SA, Kwiatkowska A, Peyrache A. Hyperpolarization-activated currents drive neuronal activation sequences in sleep. Curr Biol 2024; 34:3043-3054.e8. [PMID: 38901427 DOI: 10.1016/j.cub.2024.05.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 04/03/2024] [Accepted: 05/23/2024] [Indexed: 06/22/2024]
Abstract
Sequential neuronal patterns are believed to support information processing in the cortex, yet their origin is still a matter of debate. We report that neuronal activity in the mouse postsubiculum (PoSub), where a majority of neurons are modulated by the animal's head direction, was sequentially activated along the dorsoventral axis during sleep at the transition from hyperpolarized "DOWN" to activated "UP" states, while representing a stable direction. Computational modeling suggested that these dynamics could be attributed to a spatial gradient of hyperpolarization-activated currents (Ih), which we confirmed in ex vivo slice experiments and corroborated in other cortical structures. These findings open up the possibility that varying amounts of Ih across cortical neurons could result in sequential neuronal patterns and that traveling activity upstream of the entorhinal-hippocampal circuit organizes large-scale neuronal activity supporting learning and memory during sleep.
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Affiliation(s)
- Dhruv Mehrotra
- Montréal Neurological Institute and Hospital, Department of Neurology and Neurosurgery, 3801 Rue University, Montréal, QC H3A 2B4, Canada; Integrated Program in Neuroscience, McGill University, 3801 Rue University, Montréal, QC H3A 2B4, Canada
| | - Daniel Levenstein
- Montréal Neurological Institute and Hospital, Department of Neurology and Neurosurgery, 3801 Rue University, Montréal, QC H3A 2B4, Canada; MILA, 6666 Rue Saint-Urbain, Montréal, QC H2S 3H1, Canada
| | - Adrian J Duszkiewicz
- Montréal Neurological Institute and Hospital, Department of Neurology and Neurosurgery, 3801 Rue University, Montréal, QC H3A 2B4, Canada; Division of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Sofia Skromne Carrasco
- Montréal Neurological Institute and Hospital, Department of Neurology and Neurosurgery, 3801 Rue University, Montréal, QC H3A 2B4, Canada; Integrated Program in Neuroscience, McGill University, 3801 Rue University, Montréal, QC H3A 2B4, Canada
| | - Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Patrick Wild Centre for Research into Autism, Fragile X Syndrome & Intellectual Disabilities, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Angelika Kwiatkowska
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Adrien Peyrache
- Montréal Neurological Institute and Hospital, Department of Neurology and Neurosurgery, 3801 Rue University, Montréal, QC H3A 2B4, Canada.
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Lin JL, Chang Y, Tewari D, Cowgill J, Chanda B. Mapping the contribution of the C-linker domain to gating polarity in CNBD channels. Biophys J 2024; 123:2176-2184. [PMID: 38678368 PMCID: PMC11309966 DOI: 10.1016/j.bpj.2024.04.022] [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: 12/20/2023] [Revised: 03/23/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024] Open
Abstract
Ion channels of the cyclic nucleotide-binding domain (CNBD) family play a crucial role in the regulation of key biological processes, such as photoreception and pacemaking activity in the heart. These channels exhibit high sequence and structural similarity but differ greatly in their functional responses to membrane potential. The CNBD family includes hyperpolarization-activated ion channels and depolarization-activated ether-à-go-go channels. Structural and functional studies show that the differences in the coupling interface between these two subfamilies' voltage-sensing domain and pore domain may underlie their differential response to membrane polarity. However, other structural components may also contribute to defining the polarity differences in activation. Here, we focus on the role of the C-terminal domain, which interacts with elements in both the pore and voltage-sensing domains. By generating a series of chimeras involving the C-terminal domain derived from distant members of the CNBD family, we find that the nature of the C-termini profoundly influences the gating polarity of these ion channels. Scanning mutagenesis of the C-linker region, a helix-turn-helix motif connecting the pore helix to the CNBD, reveals that residues at the intersubunit interface between the C-linkers are crucial for hyperpolarization-dependent activation. These findings highlight the unique and unexpected role of the intersubunit interface of the C-linker region in regulating the gating polarity of voltage-gated ion channels.
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Affiliation(s)
- Jenna L Lin
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri; Graduate Program in Biochemistry, Biophysics, & Structural Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Yongchang Chang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - Debanjan Tewari
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - John Cowgill
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - Baron Chanda
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri.
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9
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Spineli H, dos Santos M, Almeida D, Gitaí D, Silva-Cavalcante M, Balikian P, Ataide-Silva T, Marinho A, Sousa F, de Araujo G. ACE gene polymorphisms (rs4340) II and DI are more responsive to the ergogenic effect of caffeine than DD on aerobic power, heart rate, and perceived exertion in a homogeneous Brazilian group of adolescent athletes. Braz J Med Biol Res 2024; 57:e13217. [PMID: 38896643 PMCID: PMC11186592 DOI: 10.1590/1414-431x2024e13217] [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: 11/21/2023] [Accepted: 04/15/2024] [Indexed: 06/21/2024] Open
Abstract
The purpose of this study was to verify the association between angiotensin-converting enzyme (ACE) genotypes DD, DI, and II and caffeine (CAF) ingestion on endurance performance, heart rate, ratio of perceived exertion (RPE), and habitual caffeine intake (HCI) of adolescent athletes. Seventy-four male adolescent athletes (age: DD=16±1.7; DI=16±2.0; II=15±1.7 years) ingested CAF (6 mg/kg) or placebo (PLA) one hour before performing the Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) test. No difference was found among groups for HCI. However, CAF increased the maximal distance covered and VO2max in DI and II genotype carriers compared to PLA (DD: Δ=31 m and 0.3 mL·kg-1·min-1; DI: Δ=286 m and 1.1 mL·kg-1·min-1; II: Δ=160 m and 1.4 mL·kg-1·min-1). Heart rate of DI and II genotype carriers increased with CAF compared to PLA, while RPE was higher in the II and lower in the DD genotypes. The correlations between HCI and maximal distance covered or VO2max were significant in the II genotype carriers with CAF. CAF increased endurance capacity, heart rate, and RPE in adolescent athletes with allele I, while endurance performance and aerobic power had a positive correlation to HCI in the II genotype group. These findings suggested that DD genotype were less responsive to CAF and that genetic variations should be taken into account when using CAF supplementation to enhance exercise performance.
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Affiliation(s)
- H. Spineli
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - M. dos Santos
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - D. Almeida
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - D. Gitaí
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - M. Silva-Cavalcante
- Instituto Federal de Educação Ciência e Tecnologia de Alagoas, Maceió, AL, Brasil
| | - P. Balikian
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - T. Ataide-Silva
- Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - A. Marinho
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - F. Sousa
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - G. de Araujo
- Instituto de Educação Física e Esporte, Universidade Federal de Alagoas, Maceió, AL, Brasil
- Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
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10
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Page DA, Ruben PC. Cannabidiol potentiates hyperpolarization-activated cyclic nucleotide-gated (HCN4) channels. J Gen Physiol 2024; 156:e202313505. [PMID: 38652080 PMCID: PMC11040500 DOI: 10.1085/jgp.202313505] [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: 03/15/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
Cannabidiol (CBD), the main non-psychotropic phytocannabinoid produced by the Cannabis sativa plant, blocks a variety of cardiac ion channels. We aimed to identify whether CBD regulated the cardiac pacemaker channel or the hyperpolarization-activated cyclic nucleotide-gated channel (HCN4). HCN4 channels are important for the generation of the action potential in the sinoatrial node of the heart and increased heart rate in response to β-adrenergic stimulation. HCN4 channels were expressed in HEK 293T cells, and the effect of CBD application was examined using a whole-cell patch clamp. We found that CBD depolarized the V1/2 of activation in holo-HCN4 channels, with an EC50 of 1.6 µM, without changing the current density. CBD also sped activation kinetics by approximately threefold. CBD potentiation of HCN4 channels occurred via binding to the closed state of the channel. We found that CBD's mechanism of action was distinct from cAMP, as CBD also potentiated apo-HCN4 channels. The addition of an exogenous PIP2 analog did not alter the ability of CBD to potentiate HCN4 channels, suggesting that CBD also acts using a unique mechanism from the known HCN4 potentiator PIP2. Lastly, to gain insight into CBD's mechanism of action, computational modeling and targeted mutagenesis were used to predict that CBD binds to a lipid-binding pocket at the C-terminus of the voltage sensor. CBD represents the first FDA-approved drug to potentiate HCN4 channels, and our findings suggest a novel starting point for drug development targeting HCN4 channels.
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Affiliation(s)
- Dana A. Page
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Peter C. Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
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11
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Hennis K, Piantoni C, Biel M, Fenske S, Wahl-Schott C. Pacemaker Channels and the Chronotropic Response in Health and Disease. Circ Res 2024; 134:1348-1378. [PMID: 38723033 PMCID: PMC11081487 DOI: 10.1161/circresaha.123.323250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease-including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate-sensitive hyperpolarization-activated current (If) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate-dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.
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Affiliation(s)
- Konstantin Hennis
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Chiara Piantoni
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Stefanie Fenske
- Department of Pharmacy, Center for Drug Research (M.B., S.F.), Ludwig-Maximilians-Universität München, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Germany (M.B., S.F.)
| | - Christian Wahl-Schott
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center Munich, Walter Brendel Centre of Experimental Medicine, Faculty of Medicine (K.H., C.P., C.W.-S.), Ludwig-Maximilians-Universität München, Germany
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12
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Civil Ürkmez Y, Avcı B, Günaydın C, Çelik ZB, Ürkmez SS. Investigation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in vitro inflammation model at molecular level. Mol Cell Biochem 2024; 479:1223-1229. [PMID: 37432633 DOI: 10.1007/s11010-023-04788-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023]
Abstract
In our study, we aimed to create an inflammation model in endothelial and macrophage cell lines and to examine the changes in the expression of hyperpolarization activated cyclic nucleotide gated (HCN) channels at the molecular level. HUVEC and RAW cell lines were used in our study. 1 µg/mL LPS was applied to the cells. Cell media were taken 6 h later. TNF-α, IL-1, IL-2, IL-4, IL-10 concentrations were measured by ELISA method. Cell media were cross-applied to cells for 24 h after LPS. HCN1/HCN2 protein levels were determined by Western-Blot method. HCN-1/HCN-2 gene expressions were determined by qRT-PCR method. In the inflammation model, a significant increase in TNF-α, IL-1, and IL-2 levels was observed in RAW cell media compared to the control. While no significant difference was observed in IL-4 level, a significant decrease was observed in IL-10 level. While a significant increase in TNF-α level was observed in HUVEC cell medium, no difference was observed in other cytokines. In our inflammation model, an 8.44-fold increase in HCN1 gene expression was observed in HUVEC cells compared to the control group. No significant change was observed in HCN2 gene expression. 6.71-fold increase in HCN1 gene expression was observed in RAW cells compared to the control. The change in HCN2 expression was not statistically significant. In the Western-Blot analysis, a statistically significant increase in HCN1 level was observed in the LPS group in HUVEC cells compared to the control; no significant increase in HCN2 level was observed. While a statistically significant increase in HCN1 level was observed in the LPS group in RAW cells compared to the control; no significant increase in HCN2 level was observed. In immunofluorescence examination, it was observed that the level of HCN1 and HCN2 proteins in the cell membrane of HUVEC and RAW cells increased in the LPS group compared to the control group. While HCN1 gene/protein levels were increased in RAW and HUVEC cells in the inflammation model, no significant change was observed in HCN2 gene/protein levels. Our data suggest that the HCN1 subtype is dominant in endothelium and macrophages and may play a critical role in inflammation.
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Affiliation(s)
- Yeşim Civil Ürkmez
- Department of Biochemistry, Samsun Training and Research Hospital, University of Health Sciences, Samsun, Turkey.
| | - Bahattin Avcı
- Department of Biochemistry, School of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Caner Günaydın
- Department of Pharmacology, School of Medicine, Samsun University, Samsun, Turkey
| | - Zülfinaz Betül Çelik
- Department of Medical Biology, School of Medicine, Samsun University, Samsun, Turkey
| | - Sebati Sinan Ürkmez
- Department of Biochemistry, School of Medicine, Ondokuz Mayıs University, Samsun, Turkey
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Sripusanapan A, Yanpiset P, Sriwichaiin S, Siri-Angkul N, Chattipakorn SC, Chattipakorn N. Hyperpolarization-activated cyclic nucleotide-gated channel inhibitor in myocardial infarction: Potential benefits beyond heart rate modulation. Acta Physiol (Oxf) 2024; 240:e14085. [PMID: 38230890 DOI: 10.1111/apha.14085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 01/18/2024]
Abstract
Myocardial infarction (MI) and its associated complications including ventricular arrhythmias and heart failure are responsible for a significant incidence of morbidity and mortality worldwide. The ensuing cardiomyocyte loss results in neurohormone-driven cardiac remodeling, which leads to chronic heart failure in MI survivors. Ivabradine is a heart rate modulation agent currently used in treatment of chronic heart failure with reduced ejection fraction. The canonical target of ivabradine is the hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in cardiac pacemaker cells. However, in post-MI hearts, HCN can also be expressed ectopically in non-pacemaker cardiomyocytes. There is an accumulation of intriguing evidence to suggest that ivabradine also possesses cardioprotective effects that are independent of heart rate reduction. This review aims to summarize and discuss the reported cardioprotective mechanisms of ivabradine beyond heart rate modulation in myocardial infarction through various molecular mechanisms including the prevention of reactive oxygen species-induced mitochondrial damage, improvement of autophagy system, modulation of intracellular calcium cycling, modification of ventricular electrophysiology, and regulation of matrix metalloproteinases.
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Affiliation(s)
- Adivitch Sripusanapan
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Panat Yanpiset
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Sirawit Sriwichaiin
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Natthaphat Siri-Angkul
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellent in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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14
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Zhang Y, Lauder GV. Energy conservation by collective movement in schooling fish. eLife 2024; 12:RP90352. [PMID: 38375853 PMCID: PMC10942612 DOI: 10.7554/elife.90352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
Many animals moving through fluids exhibit highly coordinated group movement that is thought to reduce the cost of locomotion. However, direct energetic measurements demonstrating the energy-saving benefits of fluid-mediated collective movements remain elusive. By characterizing both aerobic and anaerobic metabolic energy contributions in schools of giant danio (Devario aequipinnatus), we discovered that fish schools have a concave upward shaped metabolism-speed curve, with a minimum metabolic cost at ~1 body length s-1. We demonstrate that fish schools reduce total energy expenditure (TEE) per tail beat by up to 56% compared to solitary fish. When reaching their maximum sustained swimming speed, fish swimming in schools had a 44% higher maximum aerobic performance and used 65% less non-aerobic energy compared to solitary individuals, which lowered the TEE and total cost of transport by up to 53%, near the lowest recorded for any aquatic organism. Fish in schools also recovered from exercise 43% faster than solitary fish. The non-aerobic energetic savings that occur when fish in schools actively swim at high speed can considerably improve both peak and repeated performance which is likely to be beneficial for evading predators. These energetic savings may underlie the prevalence of coordinated group locomotion in fishes.
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Affiliation(s)
- Yangfan Zhang
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridgeUnited States
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridgeUnited States
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15
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Giunta S, Xia S, Pelliccioni G, Olivieri F. Autonomic nervous system imbalance during aging contributes to impair endogenous anti-inflammaging strategies. GeroScience 2024; 46:113-127. [PMID: 37821752 PMCID: PMC10828245 DOI: 10.1007/s11357-023-00947-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023] Open
Abstract
Inflammaging refers to the age-related low grade, sterile, chronic, systemic, and long-lasting subclinical, proinflammatory status, currently recognized as the main risk factor for development and progression of the most common age-related diseases (ARDs). Extensive investigations were focused on a plethora of proinflammatory stimuli that can fuel inflammaging, underestimating and partly neglecting important endogenous anti-inflammaging mechanisms that could play a crucial role in such age-related proinflammatory state. Studies on autonomic nervous system (ANS) functions during aging highlighted an imbalance toward an overactive sympathetic nervous system (SNS) tone, promoting proinflammatory conditions, and a diminished parasympathetic nervous system (PNS) activity, playing anti-inflammatory effects mediated by the so called cholinergic anti-inflammatory pathway (CAP). At the molecular level, CAP is characterized by signals communicated via the vagus nerve (with the possible involvement of the splenic nerves) through acetylcholine release to downregulate the inflammatory actions of macrophages, key players of inflammaging. Notably, decreased vagal function and increased burden of activated/senescent macrophages (macrophaging) probably precede the development of several age-related risk factors and diseases, while increased vagal function and reduced macrophaging could be associated with relevant reduction of risk profiles. Hypothalamic-pituitary-adrenal axis (HPA axis) is another pathway related to ANS promoting some anti-inflammatory response mainly through increased cortisol levels. In this perspective review, we highlighted that CAP and HPA, representing broadly "anti-inflammaging" mechanisms, have a reduced efficacy and lose effectiveness in aged people, a phenomenon that could contribute to fuel inflammaging. In this framework, strategies aimed to re-balance PNS/SNS activities could be explored to modulate systemic inflammaging especially at an early subclinical stage, thus increasing the chances to reach the extreme limit of human lifespan in healthy status.
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Affiliation(s)
- Sergio Giunta
- Casa Di Cura Prof. Nobili (Gruppo Garofalo (GHC)), Castiglione Dei Pepoli, Bologna, Italy
| | - Shijin Xia
- Department of Geriatrics, Shanghai Institute of Geriatrics, Huadong Hospital, Fudan University, Shanghai, China
| | | | - Fabiola Olivieri
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica Delle Marche, Via Tronto 10/A, 60126, Ancona, Italy.
- Clinical Laboratory and Molecular Diagnostic, IRCCS INRCA, Ancona, Italy.
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16
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Maltsev AV, Stern MD, Lakatta EG, Maltsev VA. A novel conceptual model of heart rate autonomic modulation based on a small-world modular structure of the sinoatrial node. Front Physiol 2023; 14:1276023. [PMID: 38148905 PMCID: PMC10750401 DOI: 10.3389/fphys.2023.1276023] [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: 08/11/2023] [Accepted: 11/27/2023] [Indexed: 12/28/2023] Open
Abstract
The present view on heartbeat initiation is that a primary pacemaker cell or a group of cells in the sinoatrial node (SAN) center paces the rest of the SAN and the atria. However, recent high-resolution imaging studies show a more complex paradigm of SAN function that emerges from heterogeneous signaling, mimicking brain cytoarchitecture and function. Here, we developed and tested a new conceptual numerical model of SAN organized similarly to brain networks featuring a modular structure with small-world topology. In our model, a lower rate module leads action potential (AP) firing in the basal state and during parasympathetic stimulation, whereas a higher rate module leads during β-adrenergic stimulation. Such a system reproduces the respective shift of the leading pacemaker site observed experimentally and a wide range of rate modulation and robust function while conserving energy. Since experimental studies found functional modules at different scales, from a few cells up to the highest scale of the superior and inferior SAN, the SAN appears to feature hierarchical modularity, i.e., within each module, there is a set of sub-modules, like in the brain, exhibiting greater robustness, adaptivity, and evolvability of network function. In this perspective, our model offers a new mainframe for interpreting new data on heterogeneous signaling in the SAN at different scales, providing new insights into cardiac pacemaker function and SAN-related cardiac arrhythmias in aging and disease.
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Affiliation(s)
| | | | | | - Victor A. Maltsev
- Intramural Research Program, National Institute on Aging, Baltimore, MD, United States
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17
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Vasylyev DV, Liu S, Waxman SG. I h current stabilizes excitability in rodent DRG neurons and reverses hyperexcitability in a nociceptive neuron model of inherited neuropathic pain. J Physiol 2023; 601:5341-5366. [PMID: 37846879 PMCID: PMC10843455 DOI: 10.1113/jp284999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023] Open
Abstract
We show here that hyperpolarization-activated current (Ih ) unexpectedly acts to inhibit the activity of dorsal root ganglion (DRG) neurons expressing WT Nav1.7, the largest inward current and primary driver of DRG neuronal firing, and hyperexcitable DRG neurons expressing a gain-of-function Nav1.7 mutation that causes inherited erythromelalgia (IEM), a human genetic model of neuropathic pain. In this study we created a kinetic model of Ih and used it, in combination with dynamic-clamp, to study Ih function in DRG neurons. We show, for the first time, that Ih increases rheobase and reduces the firing probability in small DRG neurons, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih . Our results show that Ih , due to slow gating, is not deactivated during action potentials (APs) and has a striking damping action, which reverses from depolarizing to hyperpolarizing, close to the threshold for AP generation. Moreover, we show that Ih reverses the hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes IEM. In the aggregate, our results show that Ih unexpectedly has strikingly different effects in DRG neurons as compared to previously- and well-studied cardiac cells. Within DRG neurons where Nav1.7 is present, Ih reduces depolarizing sodium current inflow due to enhancement of Nav1.7 channel fast inactivation and creates additional damping action by reversal of Ih direction from depolarizing to hyperpolarizing close to the threshold for AP generation. These actions of Ih limit the firing of DRG neurons expressing WT Nav1.7 and reverse the hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes IEM. KEY POINTS: Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, the molecular determinants of hyperpolarization-activated current (Ih ) have been characterized as a 'pain pacemaker', and thus considered to be a potential molecular target for pain therapeutics. Dorsal root ganglion (DRG) neurons express Nav1.7, a channel that is not present in central neurons or cardiac tissue. Gain-of-function mutations (GOF) of Nav1.7 identified in inherited erythromelalgia (IEM), a human genetic model of neuropathic pain, produce DRG neuron hyperexcitability, which in turn produces severe pain. We found that Ih increases rheobase and reduces firing probability in small DRG neurons expressing WT Nav1.7, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih . We also demonstrate that Ih reverses the hyperexcitability of DRG neurons expressing a GOF Nav1.7 mutation (L858H) that causes IEM. Our results show that, in contrast to cardiac cells and CNS neurons, Ih acts to stabilize DRG neuron excitability and prevents excessive firing.
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Affiliation(s)
- Dmytro V. Vasylyev
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
| | - Shujun Liu
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
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18
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Kennedy AR, Cruickshank L, Maher P, McKinnon Z. A structural comparison of salt forms of dopamine with the structures of other phenylethylamines. Acta Crystallogr C Struct Chem 2023; 79:386-394. [PMID: 37721716 PMCID: PMC10551880 DOI: 10.1107/s2053229623007696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/04/2023] [Indexed: 09/19/2023] Open
Abstract
The structures of four salt forms of dopamine are reported. These are dopamine [2-(3,4-dihydroxyphenyl)ethan-1-aminium] benzoate, C8H12NO2+·C7H5O2-, I, dopamine 4-nitrobenzoate, C8H12NO2+·C7H4NO4-, II, dopamine ethanedisulfonate, 2C8H12NO2+·C2H4O6S22-, III, and dopamine 4-hydroxybenzenesulfonate monohydrate, C8H12NO2+·C6H5O4S-·H2O, IV. In all four structures, the dopamine cation adopts an extended conformation. Intermolecular interaction motifs that are common in the salt forms of tyramine can be found in related dopamine structures, but hydrogen bonding in the dopamine structures appear to be more variable and less predictable than for tyramine. Packing analysis discovered three dopamine-containing groups of structures that can be described as isostructural with regards to the cation positions. Two of these groups contain both dopamine and tyramine species, and one of these is also highly variable in other ways too, containing anhydrous and hydrated forms, different anion types and ionized and neutral phenylethylamine species. As such, the group illustrates that packing behaviour can be robust and similar even where intermolecular interactions such as hydrogen bonds are very different.
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Affiliation(s)
- Alan R. Kennedy
- Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, United Kingdom
| | - Laura Cruickshank
- Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, United Kingdom
| | - Pamela Maher
- Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, United Kingdom
| | - Zoe McKinnon
- Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, United Kingdom
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Mu L, Liu X, Yu H, Vickstrom CR, Friedman V, Kelly TJ, Hu Y, Su W, Liu S, Mantsch JR, Liu QS. cAMP-mediated upregulation of HCN channels in VTA dopamine neurons promotes cocaine reinforcement. Mol Psychiatry 2023; 28:3930-3942. [PMID: 37845497 PMCID: PMC10730389 DOI: 10.1038/s41380-023-02290-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 09/25/2023] [Accepted: 10/03/2023] [Indexed: 10/18/2023]
Abstract
Chronic cocaine exposure induces enduring neuroadaptations that facilitate motivated drug taking. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are known to modulate neuronal firing and pacemaker activity in ventral tegmental area (VTA) dopamine neurons. However, it remained unknown whether cocaine self-administration affects HCN channel function and whether HCN channel activity modulates motivated drug taking. We report that rat VTA dopamine neurons predominantly express Hcn3-4 mRNA, while VTA GABA neurons express Hcn1-4 mRNA. Both neuronal types display similar hyperpolarization-activated currents (Ih), which are facilitated by acute increases in cAMP. Acute cocaine application decreases voltage-dependent activation of Ih in VTA dopamine neurons, but not in GABA neurons. Unexpectedly, chronic cocaine self-administration results in enhanced Ih selectively in VTA dopamine neurons. This differential modulation of Ih currents is likely mediated by a D2 autoreceptor-induced decrease in cAMP as D2 (Drd2) mRNA is predominantly expressed in dopamine neurons, whereas D1 (Drd1) mRNA is barely detectable in the VTA. Moreover, chronically decreased cAMP via Gi-DREADD stimulation leads to an increase in Ih in VTA dopamine neurons and enhanced binding of HCN3/HCN4 with tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b), an auxiliary subunit that is known to facilitate HCN channel surface trafficking. Finally, we show that systemic injection and intra-VTA infusion of the HCN blocker ivabradine reduces cocaine self-administration under a progressive ratio schedule and produces a downward shift of the cocaine dose-response curve. Our results suggest that cocaine self-administration induces an upregulation of Ih in VTA dopamine neurons, while HCN inhibition reduces the motivation for cocaine intake.
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Affiliation(s)
- Lianwei Mu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Xiaojie Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Hao Yu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Casey R Vickstrom
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Vladislav Friedman
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Thomas J Kelly
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ying Hu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Wantang Su
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
- Department of Exercise Physiology, Beijing Sport University, Beijing, 100084, China
| | - Shuai Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - John R Mantsch
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Qing-Song Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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20
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Catacuzzeno L, Conti F, Franciolini F. Fifty years of gating currents and channel gating. J Gen Physiol 2023; 155:e202313380. [PMID: 37410612 PMCID: PMC10324510 DOI: 10.1085/jgp.202313380] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023] Open
Abstract
We celebrate this year the 50th anniversary of the first electrophysiological recordings of the gating currents from voltage-dependent ion channels done in 1973. This retrospective tries to illustrate the context knowledge on channel gating and the impact gating-current recording had then, and how it continued to clarify concepts, elaborate new ideas, and steer the scientific debate in these 50 years. The notion of gating particles and gating currents was first put forward by Hodgkin and Huxley in 1952 as a necessary assumption for interpreting the voltage dependence of the Na and K conductances of the action potential. 20 years later, gating currents were actually recorded, and over the following decades have represented the most direct means of tracing the movement of the gating charges and gaining insights into the mechanisms of channel gating. Most work in the early years was focused on the gating currents from the Na and K channels as found in the squid giant axon. With channel cloning and expression on heterologous systems, other channels as well as voltage-dependent enzymes were investigated. Other approaches were also introduced (cysteine mutagenesis and labeling, site-directed fluorometry, cryo-EM crystallography, and molecular dynamics [MD] modeling) to provide an integrated and coherent view of voltage-dependent gating in biological macromolecules. The layout of this retrospective reflects the past 50 years of investigations on gating currents, first addressing studies done on Na and K channels and then on other voltage-gated channels and non-channel structures. The review closes with a brief overview of how the gating-charge/voltage-sensor movements are translated into pore opening and the pathologies associated with mutations targeting the structures involved with the gating currents.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Franco Conti
- Department of Physics, University of Genova, Genova, Italy
| | - Fabio Franciolini
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
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21
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Chen M, Wu Q. Roles and mechanisms of natural drugs on sinus node dysfunction. Biomed Pharmacother 2023; 164:114777. [PMID: 37229801 DOI: 10.1016/j.biopha.2023.114777] [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: 03/23/2023] [Revised: 04/18/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Sinus node dysfunction is a common arrhythmia disorder with a high incidence and significant social and economic burden. Currently, there are no effective drugs for treating chronic sinus node dysfunction. The disease is associated with ion channel disturbances caused by aging, fibrosis, inflammation, oxidative stress, and autonomic dysfunction. Natural active substances and Chinese herbal medicines have been widely used and extensively studied in the medical community for the treatment of arrhythmias. Multiple studies have demonstrated that various active ingredients and Chinese herbal medicines, such as astragaloside IV, quercetin, and ginsenosides, exhibit antioxidant effects, reduce fibrosis, and maintain ion channel stability, providing promising drugs for treating sinus node dysfunction. This article summarizes the research progress on natural active ingredients and Chinese herbal formulas that regulate sick sinoatrial node function, providing valuable references for the treatment of sinus node dysfunction.
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Affiliation(s)
- Meilian Chen
- Quanzhou Hospital of Traditional Chinese Medicine, Fujian 362000, China
| | - Qiaomin Wu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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Wojciechowski MN, Schreiber S, Jose J. A Novel Flow Cytometry-Based Assay for the Identification of HCN4 CNBD Ligands. Pharmaceuticals (Basel) 2023; 16:ph16050710. [PMID: 37242492 DOI: 10.3390/ph16050710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are promising therapeutic targets because of their association with the genesis of several diseases. The identification of selective compounds that alter cAMP-induced ion channel modulation by binding to the cyclic nucleotide-binding domain (CNBD) will facilitate HCN channel-specific drug development. In this study, a fast and protein purification-free ligand-binding approach with a surface-displayed HCN4 C-Linker-CNBD on E. coli is presented. 8-Fluo-cAMP ligand binding was monitored by single-cell analysis via flow cytometry, and a Kd-value of 173 ± 46 nM was determined. The Kd value was confirmed by ligand depletion analysis and equilibrium state measurements. Applying increasing concentrations of cAMP led to a concentration-dependent decrease in fluorescence intensity, indicating a displacement of 8-Fluo-cAMP. A Ki-value of 8.5 ± 2 µM was determined. The linear relationship of IC50 values obtained for cAMP as a function of ligand concentration confirmed the competitive binding mode: IC50: 13 ± 2 µM/16 ± 3 µM/23 ± 1 µM/27 ± 1 µM for 50 nM/150 nM/250 nM/500 nM 8-Fluo-cAMP. A similar competitive mode of binding was confirmed for 7-CH-cAMP, and an IC50 value of 230 ± 41 nM and a Ki of 159 ± 29 nM were determined. Two established drugs were tested in the assay. Ivabradine, an approved HCN channel pore blocker and gabapentin, is known to bind to HCN4 channels in preference to other isoforms with an unknown mode of action. As expected, ivabradine had no impact on ligand binding. In addition, gabapentin had no influence on 8-Fluo-cAMP's binding to HCN4-CNBD. This is the first indication that gabapentin is not interacting with this part of the HCN4 channel. The ligand-binding assay as described can be used to determine binding constants for ligands such as cAMP and derivatives. It could also be applied for the identification of new ligands binding to the HCN4-CNBD.
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Affiliation(s)
- Magdalena N Wojciechowski
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
| | - Sebastian Schreiber
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
| | - Joachim Jose
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
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Wu X, Cunningham KP, Ramentol R, Perez ME, Larsson HP. Similar voltage-sensor movement in spHCN channels can cause closing, opening, or inactivation. J Gen Physiol 2023; 155:e202213170. [PMID: 36752823 PMCID: PMC9948645 DOI: 10.1085/jgp.202213170] [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: 04/08/2022] [Revised: 11/22/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels contribute to the rhythmic firing of pacemaker neurons and cardiomyocytes. Mutations in HCN channels are associated with cardiac arrhythmia and epilepsy. HCN channels belong to the superfamily of voltage-gated K+ channels, most of which are activated by depolarization. HCN channels, however, are activated by hyperpolarization. The mechanism behind this reversed gating polarity of HCN channels is not clear. We here show that sea urchin HCN (spHCN) channels with mutations in the C-terminal part of the voltage sensor use the same voltage-sensor movement to either close or open in response to hyperpolarizations depending on the absence or presence of cAMP. Our results support that non-covalent interactions at the C-terminal end of the voltage sensor are critical for HCN gating polarity. These interactions are also critical for the proper closing of the channels because these mutations exhibit large constitutive currents. Since a similar voltage-sensor movement can cause both depolarization- and hyperpolarization-activation in the same channel, this suggests that the coupling between the voltage sensor and the pore is changed to create channels opened by different polarities. We also show an identical voltage-sensor movement in activated and inactivated spHCN channels and suggest a model for spHCN activation and inactivation. Our results suggest the possibility that channels open by opposite voltage dependence, such as HCN and the related EAG channels, use the same voltage-sensor movement but different coupling mechanisms between the voltage sensor and the gate.
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Affiliation(s)
- Xiaoan Wu
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Kevin P. Cunningham
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rosamary Ramentol
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Marta E. Perez
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - H. Peter Larsson
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
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Yan Z, Zhong L, Zhu W, Chung SK, Hou P. Chinese herbal medicine for the treatment of cardiovascular diseases ─ targeting cardiac ion channels. Pharmacol Res 2023; 192:106765. [PMID: 37075871 DOI: 10.1016/j.phrs.2023.106765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/04/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023]
Abstract
Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality, imposing an increasing global health burden. Cardiac ion channels (voltage-gated NaV, CaV, KVs, and others) synergistically shape the cardiac action potential (AP) and control the heartbeat. Dysfunction of these channels, due to genetic mutations, transcriptional or post-translational modifications, may disturb the AP and lead to arrhythmia, a major risk for CVD patients. Although there are five classes of anti-arrhythmic drugs available, they can have varying levels of efficacies and side effects on patients, possibly due to the complex pathogenesis of arrhythmias. As an alternative treatment option, Chinese herbal remedies have shown promise in regulating cardiac ion channels and providing anti-arrhythmic effects. In this review, we first discuss the role of cardiac ion channels in maintaining normal heart function and the pathogenesis of CVD, then summarize the classification of Chinese herbal compounds, and elaborate detailed mechanisms of their efficacy in regulating cardiac ion channels and in alleviating arrhythmia and CVD. We also address current limitations and opportunities for developing new anti-CVD drugs based on Chinese herbal medicines.
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Affiliation(s)
- Zhenzhen Yan
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Ling Zhong
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Wandi Zhu
- Cardiovascular Medicine Division and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Sookja Kim Chung
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China; Faculty of Medicine & Faculty of Innovation Engineering at Macau University of Science and Technology, Taipa, Macao SAR, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China
| | - Panpan Hou
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China; Macau University of Science and Technology Zhuhai MUST Science and Technology Research Institute. Zhuhai, Guangdong, China.
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25
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Congreve SD, Main A, Butler AS, Gao X, Brown E, Du C, Choisy SC, Cheng H, Hancox JC, Fuller W. Palmitoylation regulates the magnitude of HCN4-mediated currents in mammalian cells. Front Physiol 2023; 14:1163339. [PMID: 37123274 PMCID: PMC10133559 DOI: 10.3389/fphys.2023.1163339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
The sinoatrial node (SAN) and subsidiary pacemakers in the cardiac conduction system generate spontaneous electrical activity which is indispensable for electrical and therefore contractile function of the heart. The hyperpolarisation-activated cyclic nucleotide-gated channel HCN4 is responsible for genesis of the pacemaker "funny" current during diastolic depolarisation. S-palmitoylation, the reversible conjugation of the fatty acid palmitate to protein cysteine sulfhydryls, regulates the activity of key cardiac Na+ and Ca2+ handling proteins, influencing their membrane microdomain localisation and function. We investigated HCN4 palmitoylation and its functional consequences in engineered human embryonic kidney 293T cells as well as endogenous HCN4 in neonatal rat ventricular myocytes. HCN4 was palmitoylated in all experimental systems investigated. We mapped the HCN4 palmitoylation sites to a pair of cysteines in the HCN4 intracellular amino terminus. A double cysteine-to-alanine mutation CC93A/179AA of full length HCN4 caused a ∼67% reduction in palmitoylation in comparison to wild type HCN4. We used whole-cell patch clamp to evaluate HCN4 current (IHCN4) in stably transfected 293T cells. Removal of the two N-terminal palmitoylation sites did not significantly alter half maximal activation voltage of IHCN4 or the activation slope factor. IHCN4 was significantly larger in cells expressing wild type compared to non-palmitoylated HCN4 across a range of voltages. Phylogenetic analysis revealed that although cysteine 93 is widely conserved across all classes of HCN4 vertebrate orthologs, conservation of cysteine 179 is restricted to placental mammals. Collectively, we provide evidence for functional regulation of HCN4 via palmitoylation of its amino terminus in vertebrates. We suggest that by recruiting the amino terminus to the bilayer, palmitoylation enhances the magnitude of HCN4-mediated currents, but does not significantly affect the kinetics.
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Affiliation(s)
- Samitha Dilini Congreve
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Alice Main
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Andrew S. Butler
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Xing Gao
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Elaine Brown
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
| | - Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Stephanié C. Choisy
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Hongwei Cheng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - William Fuller
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, United Kingdom
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Barbuti A, Baruscotti M, Bucchi A. The “Funny” Pacemaker Current. HEART RATE AND RHYTHM 2023:63-87. [DOI: 10.1007/978-3-031-33588-4_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
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Muacevic A, Adler JR. A Systematic Review of Heart Rate Variability as a Measure of Stress in Medical Professionals. Cureus 2023; 15:e34345. [PMID: 36865953 PMCID: PMC9974008 DOI: 10.7759/cureus.34345] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2022] [Indexed: 03/04/2023] Open
Abstract
Understanding the physiological effects of responding to crises is a critical component in understanding how to manage and prepare medical professionals to be crisis responders. Heart rate variability (HRV) is the variation in rate between a succession of R-R intervals. This variation is not only affected by physiological processes such as respiration or metabolic rate but is also directly controlled by the autonomic nervous system. As such, heart rate variability has been proposed as a noninvasive tool to measure the physiological stress response. The aim of this systematic review is to consolidate heart rate variability literature in the context of medical emergencies to determine if heart rate variability changes predictably from baseline when responding to medical crises. This may demonstrate utility as an objective, noninvasive measure of stress response. A systematic literature review of six databases yielded 413 articles, 17 of which met our inclusion criteria of being written in English, measuring HRV in healthcare providers, and measuring HRV in real or simulated medical resuscitations or procedures. Articles were then analyzed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) scoring system. Out of the 17 articles reviewed, 11 demonstrated statistically significant results showing heart rate variability responding in a predictable manner to stress. Three articles utilized a medical simulation as the stressor, six used medical procedures, and eight used medical emergencies encountered during clinical work. Overall, a predictable trend in heart rate variability metrics of standard deviation from the mean value of normal-to-normal (N-N) intervals (SDNN), root mean square of the successive differences (RMSSD), mean number of times per time interval in which the change in successive normal sinus (N-N) intervals exceeds 50 ms (PNN50), low frequency % (LF%), and low-frequency-to-high-frequency ratio (LF/HF) was observed when responding to stress. This systematic literature review showed that heart rate variability among healthcare providers responding to stressful scenarios follows a predictable pattern of change and expands our understanding of the physiology of stress in healthcare providers. This review supports the use of HRV to monitor stress during high-fidelity simulation to ensure that appropriate physiological arousal is achieved during the training of medical personnel.
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Negrini D. Morphological, Mechanical and Hydrodynamic Aspects of Diaphragmatic Lymphatics. BIOLOGY 2022; 11:biology11121803. [PMID: 36552311 PMCID: PMC9775868 DOI: 10.3390/biology11121803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022]
Abstract
The diaphragmatic lymphatic vascular network has unique anatomical characteristics. Studying the morphology and distribution of the lymphatic network in the mouse diaphragm by fluorescence-immunohistochemistry using LYVE-1 (a lymphatic endothelial marker) revealed LYVE1+ structures on both sides of the diaphragm-both in its the muscular and tendinous portion, but with different vessel density and configurations. On the pleural side, most LYVE1+ configurations are vessel-like with scanty stomata, while the peritoneal side is characterized by abundant LYVE1+ flattened lacy-ladder shaped structures with several stomata-like pores, particularly in the muscular portion. Such a complex, three-dimensional organization is enriched, at the peripheral rim of the muscular diaphragm, with spontaneously contracting lymphatic vessel segments able to prompt contractile waves to adjacent collecting lymphatics. This review aims at describing how the external tissue forces developing in the diaphragm, along with cyclic cardiogenic and respiratory swings, interplay with the spontaneous contraction of lymphatic vessel segments at the peripheral diaphragmatic rim to simultaneously set and modulate lymph flow from the pleural and peritoneal cavities. These details may provide useful in understanding the role of diaphragmatic lymphatics not only in physiological but, more so, in pathophysiological circumstances such as in dialysis, metastasis or infection.
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Affiliation(s)
- Daniela Negrini
- Department of Medicine and Surgery, University of Insubria, 21100 Varese, Italy
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29
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Peters CH, Rickert C, Morotti S, Grandi E, Aronow KA, Beam KG, Proenza C. The funny current If is essential for the fight-or-flight response in cardiac pacemaker cells. J Gen Physiol 2022; 154:e202213193. [PMID: 36305844 PMCID: PMC9812006 DOI: 10.1085/jgp.202213193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/22/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
The sympathetic nervous system fight-or-flight response is characterized by a rapid increase in heart rate, which is mediated by an increase in the spontaneous action potential (AP) firing rate of pacemaker cells in the sinoatrial node. Sympathetic neurons stimulate sinoatrial myocytes (SAMs) by activating β adrenergic receptors (βARs) and increasing cAMP. The funny current (If) is among the cAMP-sensitive currents in SAMs. If is critical for pacemaker activity, however, its role in the fight-or-flight response remains controversial. In this study, we used AP waveform analysis, machine learning, and dynamic clamp experiments in acutely isolated SAMs from mice to quantitatively define the AP waveform changes and role of If in the fight-or-flight increase in AP firing rate. We found that while βAR stimulation significantly altered nearly all AP waveform parameters, the increase in firing rate was only correlated with changes in a subset of parameters (diastolic duration, late AP duration, and diastolic depolarization rate). Dynamic clamp injection of the βAR-sensitive component of If showed that it accounts for ∼41% of the fight-or-flight increase in AP firing rate and 60% of the decrease in the interval between APs. Thus, If is an essential contributor to the fight-or-flight increase in heart rate.
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Affiliation(s)
- Colin H. Peters
- Department of Physiology & Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Christian Rickert
- Department of Physiology & Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Stefano Morotti
- Department of Pharmacology, University of California, Davis, School of Medicine, Davis, CA
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, School of Medicine, Davis, CA
| | | | - Kurt G. Beam
- Department of Physiology & Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Catherine Proenza
- Department of Physiology & Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
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30
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Smajdor J, Paczosa-Bator B, Piech R. Advances on Hormones and Steroids Determination: A Review of Voltammetric Methods since 2000. MEMBRANES 2022; 12:1225. [PMID: 36557132 PMCID: PMC9782681 DOI: 10.3390/membranes12121225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
This article presents advances in the electrochemical determination of hormones and steroids since 2000. A wide spectrum of techniques and working electrodes have been involved in the reported measurements in order to obtain the lowest possible limits of detection. The voltammetric and polarographic techniques, due to their sensitivity and easiness, could be used as alternatives to other, more complicated, analytical assays. Still, growing interest in designing a new construction of the working electrodes enables us to prepare new measurement procedures and obtain lower limits of detection. A brief description of the measured compounds has been presented, along with a comparison of the obtained results.
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31
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Hu Z, Gao S, Yang J, Xu B, Tang W, Bradley JL, Peberdy MA, Ornato JP. IVABRADINE-INDUCED HEART RATE REDUCTION INCREASES THE SEVERITY OF POSTRESUSCITATION MYOCARDIAL DYSFUNCTION IN A RAT MODEL OF CARDIOPULMONARY RESUSCITATION. Shock 2022; 58:573-581. [PMID: 36548647 PMCID: PMC9803391 DOI: 10.1097/shk.0000000000002020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/14/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022]
Abstract
ABSTRACT Aims: A rapid heart rate (HR) that occurs after cardiopulmonary resuscitation (CPR) is a short-term compensatory mechanism preserving cardiac output. However, if of long duration, it is unfavorable for myocardial function postresuscitation because of disrupted balance between myocardial oxygen supply and demand. This raises the assumption that such a sustained fast HR should be regulated. The present study aimed to investigate the follow-on effect of ivabradine (a specific inhibitor of the I f current of the sinoatrial node)-induced HR reduction (HRR) on postresuscitation myocardial function in a rat model of CPR. Methods and results: Six minutes of ventricular fibrillation and 8 min of CPR were performed on Sprague-Dawley rats. All 32 resuscitated animals were then randomized into saline and ivabradine groups, each group having nonsurvival and survival subgroups (n = 8 each). Saline or ivabradine (0.5 mL/kg) was administered at 1 h postresuscitation. Heart rate, myocardial function as expressed by cardiac output, ejection fraction, and myocardial performance index were assessed at baseline and hourly from 1 to 5 h postresuscitation. Heart rate variability was analyzed at baseline and at 1, 3, and 5 h postresuscitation. Serum epinephrine and cardiac troponin I at baseline and at 1, 3, and 5 h postresuscitation in nonsurvival subgroup were measured. Survival duration in the survival subgroup was observed. The baseline HR was approximately 390 beats/min (bpm). After resuscitation, an average increase of Δ ≈ +15 bpm (relative ratio ≈ +3.8%) with a resultant HR of 405 bpm lasting more than 5 h occurred. Ivabradine group achieved a steady HRR of Δ ≈ -30 bpm (relative ratio ≈ -7.4%) as compared with saline group ( P < 0.01). Postresuscitation myocardial function was significantly worse in the ivabradine group (all P < 0.01). Heart rate variability was significantly impaired in the ivabradine group (all P < 0.05). Serum cardiac troponin I and epinephrine concentration were significantly higher in the ivabradine group (all P < ?0.01). Survival duration was significantly shortened in the ivabradine group as compared with the saline group (388 vs. 526 min, P < ?0.01). Conclusions: Ivabradine-induced HRR increases the severity of postresuscitation myocardial dysfunction and shortens survival duration in a rat model of CPR.
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Affiliation(s)
- Zhangle Hu
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei, Anhui, China
- Department of Cardiology, The Second Hospital of Anhui Medical University, Hefei, Anhui, China
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Shan Gao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei, Anhui, China
| | - Jin Yang
- Department of Respiratory Medicine, The Second Hospital of Anhui Medical University, Hefei, China
| | - Banglong Xu
- Department of Cardiology, The Second Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Wanchun Tang
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Jennifer L. Bradley
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Mary Ann Peberdy
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
| | - Joseph P. Ornato
- Weil Institute of Emergency and Critical Care Research, Virginia Commonwealth University, Richmond, VA
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Accili E. When Is a Potassium Channel Not a Potassium Channel? FUNCTION (OXFORD, ENGLAND) 2022; 3:zqac052. [PMID: 36325512 PMCID: PMC9614928 DOI: 10.1093/function/zqac052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 01/06/2023]
Abstract
Ever since they were first observed in Purkinje fibers of the heart, funny channels have had close connections to potassium channels. Indeed, funny channels were initially thought to produce a potassium current in the heart called I K2. However, funny channels are completely unlike potassium channels in ways that make their contributions to the physiology of cells unique. An important difference is the greater ability for sodium to permeate funny channels. Although it does not flow through the funny channel as easily as does potassium, sodium does permeate well enough to allow for depolarization of cells following a strong hyperpolarization. This is critical for the function of funny channels in places like the heart and brain. Computational analyses using recent structures of the funny channels have provided a possible mechanism for their unusual permeation properties.
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33
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Aranberri-Ruiz A, Aritzeta A, Olarza A, Soroa G, Mindeguia R. Reducing Anxiety and Social Stress in Primary Education: A Breath-Focused Heart Rate Variability Biofeedback Intervention. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10181. [PMID: 36011817 PMCID: PMC9407856 DOI: 10.3390/ijerph191610181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/13/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Primary school students suffer from high levels of anxiety and stress. Having emotional regulation abilities can help them to manage challenging emotional situations. Conscious and slow breathing is a physiological, emotional regulation strategy that is feasible for primary school students to learn. Following Polyvagal Theory and PMER Theory, this research presents the results of a breath-focused heart rate variability biofeedback intervention. The intervention aimed to reduce anxiety and physiological and social stress in primary school children. A total of 585 students (46.4% girls and 53.6% boys) from the same public school, aged between 7 and 12 years (M = 8.51; SD = 1.26), participated in this study. To assess the impact of training, a mixed design was used with two groups (Treatment and Control groups), two evaluation phases (Pretest and Post-test), and three educational cycles (first, second and third cycles). To examine heart rate variability, emWave software was used and anxiety and social stress were measured by the BASC II test. The results showed that after the intervention, the students learned to breathe consciously. Moreover, they reduced their levels of anxiety (M(SD)pretest = 12.81(2.22) vs. M(SD)posttest = 13.70(1.98)) and stress (M(SD)pretest = 12.20(1.68) vs. M(SD)posttest = 12.90(1.44)). The work also discusses the limitations and benefits of this type of intervention in primary schools.
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Affiliation(s)
- Ainara Aranberri-Ruiz
- Department of Basic Psychological Process and Development, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Gipuzkoa, Spain
| | - Aitor Aritzeta
- Department of Basic Psychological Process and Development, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Gipuzkoa, Spain
| | - Amaiur Olarza
- Department of Basic Psychological Process and Development, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Gipuzkoa, Spain
| | - Goretti Soroa
- Department of Clinical and Health Psychology and Research Methodology, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Gipuzkoa, Spain
| | - Rosa Mindeguia
- Department of Basic Psychological Process and Development, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Gipuzkoa, Spain
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Peters CH, Singh RK, Bankston JR, Proenza C. Regulation of HCN Channels by Protein Interactions. Front Physiol 2022; 13:928507. [PMID: 35795651 PMCID: PMC9251338 DOI: 10.3389/fphys.2022.928507] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-sensitive (HCN) channels are key regulators of subthreshold membrane potentials in excitable cells. The four mammalian HCN channel isoforms, HCN1-HCN4, are expressed throughout the body, where they contribute to diverse physiological processes including cardiac pacemaking, sleep-wakefulness cycles, memory, and somatic sensation. While all HCN channel isoforms produce currents when expressed by themselves, an emerging list of interacting proteins shape HCN channel excitability to influence the physiologically relevant output. The best studied of these regulatory proteins is the auxiliary subunit, TRIP8b, which binds to multiple sites in the C-terminus of the HCN channels to regulate expression and disrupt cAMP binding to fine-tune neuronal HCN channel excitability. Less is known about the mechanisms of action of other HCN channel interaction partners like filamin A, Src tyrosine kinase, and MinK-related peptides, which have a range of effects on HCN channel gating and expression. More recently, the inositol trisphosphate receptor-associated cGMP-kinase substrates IRAG1 and LRMP (also known as IRAG2), were discovered as specific regulators of the HCN4 isoform. This review summarizes the known protein interaction partners of HCN channels and their mechanisms of action and identifies gaps in our knowledge.
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Affiliation(s)
- Colin H. Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Rohit K. Singh
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - John R. Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- *Correspondence: Catherine Proenza,
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3D-printed electrochemical platform with multi-purpose carbon black sensing electrodes. Mikrochim Acta 2022; 189:235. [PMID: 35633399 PMCID: PMC9142345 DOI: 10.1007/s00604-022-05323-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/27/2022] [Indexed: 11/11/2022]
Abstract
The 3D printing is described of a complete and portable system comprising a batch injection analysis (BIA) cell and an electrochemical platform with eight sensing electrodes. Both BIA and electrochemical cells were printed within 3.4 h using a multimaterial printer equipped with insulating, flexible, and conductive filaments at cost of ca. ~ U$ 1.2 per unit, and their integration was based on a threadable assembling without commercial component requirements. Printed electrodes were exposed to electrochemical/Fenton pre-treatments to improve the sensitivity. Scanning electron microscopy and electrochemical impedance spectroscopy measurements upon printed materials revealed high-fidelity 3D features (90 to 98%) and fast heterogeneous rate constants ((1.5 ± 0.1) × 10−3 cm s−1). Operational parameters of BIA cell were optimized using a redox probe composed of [Fe(CN)6]4−/3− under stirring and the best analytical performance was achieved using a dispensing rate of 9.0 µL s−1 and an injection volume of 2.0 µL. The proof of concept of the printed device for bioanalytical applications was evaluated using adrenaline (ADR) as target analyte and its redox activities were carefully evaluated through different voltammetric techniques upon multiple 3D-printed electrodes. The coupling of BIA system with amperometric detection ensured fast responses with well-defined peak width related to the oxidation of ADR applying a potential of 0.4 V vs Ag. The fully 3D-printed system provided suitable analytical performance in terms of repeatability and reproducibility (RSD ≤ 6%), linear concentration range (5 to 40 µmol L−1; R2 = 0.99), limit of detection (0.61 µmol L−1), and high analytical frequency (494 ± 13 h−1). Lastly, artificial urine samples were spiked with ADR solutions at three different concentration levels and the obtained recovery values ranged from 87 to 118%, thus demonstrating potentiality for biological fluid analysis. Based on the analytical performance, the complete device fully printed through additive manufacturing technology emerges as powerful, inexpensive, and portable tool for electroanalytical applications involving biologically relevant compounds.
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Paradigm shift: new concepts for HCN4 function in cardiac pacemaking. Pflugers Arch 2022; 474:649-663. [PMID: 35556164 PMCID: PMC9192375 DOI: 10.1007/s00424-022-02698-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 11/05/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide–gated (HCN) channels are the molecular correlate of the If current and are critically involved in controlling neuronal excitability and the autonomous rhythm of the heart. The HCN4 isoform is the main HCN channel subtype expressed in the sinoatrial node (SAN), a tissue composed of specialized pacemaker cells responsible for generating the intrinsic heartbeat. More than 40 years ago, the If current was first discovered in rabbit SAN tissue. Along with this discovery, a theory was proposed that cyclic adenosine monophosphate–dependent modulation of If mediates heart rate regulation by the autonomic nervous system—a process called chronotropic effect. However, up to the present day, this classical theory could not be reliably validated. Recently, new concepts emerged confirming that HCN4 channels indeed play an important role in heart rate regulation. However, the cellular mechanism by which HCN4 controls heart rate turned out to be completely different than originally postulated. Here, we review the latest findings regarding the physiological role of HCN4 in the SAN. We describe a newly discovered mechanism underlying heart rate regulation by HCN4 at the tissue and single cell levels, and we discuss these observations in the context of results from previously studied HCN4 mouse models.
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Signaling cascades in the failing heart and emerging therapeutic strategies. Signal Transduct Target Ther 2022; 7:134. [PMID: 35461308 PMCID: PMC9035186 DOI: 10.1038/s41392-022-00972-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/13/2022] [Accepted: 03/20/2022] [Indexed: 12/11/2022] Open
Abstract
Chronic heart failure is the end stage of cardiac diseases. With a high prevalence and a high mortality rate worldwide, chronic heart failure is one of the heaviest health-related burdens. In addition to the standard neurohormonal blockade therapy, several medications have been developed for chronic heart failure treatment, but the population-wide improvement in chronic heart failure prognosis over time has been modest, and novel therapies are still needed. Mechanistic discovery and technical innovation are powerful driving forces for therapeutic development. On the one hand, the past decades have witnessed great progress in understanding the mechanism of chronic heart failure. It is now known that chronic heart failure is not only a matter involving cardiomyocytes. Instead, chronic heart failure involves numerous signaling pathways in noncardiomyocytes, including fibroblasts, immune cells, vascular cells, and lymphatic endothelial cells, and crosstalk among these cells. The complex regulatory network includes protein-protein, protein-RNA, and RNA-RNA interactions. These achievements in mechanistic studies provide novel insights for future therapeutic targets. On the other hand, with the development of modern biological techniques, targeting a protein pharmacologically is no longer the sole option for treating chronic heart failure. Gene therapy can directly manipulate the expression level of genes; gene editing techniques provide hope for curing hereditary cardiomyopathy; cell therapy aims to replace dysfunctional cardiomyocytes; and xenotransplantation may solve the problem of donor heart shortages. In this paper, we reviewed these two aspects in the field of failing heart signaling cascades and emerging therapeutic strategies based on modern biological techniques.
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Bauer D, Wissmann J, Moroni A, Thiel G, Hamacher K. Weak Cation Selectivity in HCN Channels Results From K +-Mediated Release of Na + From Selectivity Filter Binding Sites. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqac019. [PMID: 36156894 PMCID: PMC9492253 DOI: 10.1093/function/zqac019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 01/07/2023]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels generate the pacemaker current which plays an important role in the timing of various biological processes like the heart beat. We used umbrella sampling to explore the potential of mean force for the conduction of potassium and sodium through the open HCN4 pore. Our data explain distinct functional features like low unitary conductance and weak selectivity as a result of high energetic barriers inside the selectivity filter of this channel. They exceed the 3-5 kJ/mol threshold which is presumed as maximal barrier for diffusion-limited conductance. Furthermore, simulations provide a thermodynamic explanation for the weak cation selectivity of HCN channels that contain only two ion binding sites in the selectivity filter (SF). We find that sodium ions bind more strongly to the SF than potassium and are easier released by binding of potassium than of another sodium. Hence ion transport and selectivity in HCN channels is not determined by the same mechanism as in potassium-selective channels; it rather relies on sodium as a weak blocker that can only be released by potassium.
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Affiliation(s)
- Daniel Bauer
- Department of Biology and Centre for Synthetic Biology, TU Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
| | - Jan Wissmann
- Department of Physics, TU Darmstadt, Schlossgartenstrasse 7, 64289 Darmstadt, Germany
| | - Anna Moroni
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milan, Italy
| | | | - Kay Hamacher
- Department of Biology and Centre for Synthetic Biology, TU Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany,Department of Physics, TU Darmstadt, Schlossgartenstrasse 7, 64289 Darmstadt, Germany
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Remme CA. Getting to the heart of rhythm: A century of progress. Physiol Rev 2022; 102:1553-1567. [PMID: 35343827 DOI: 10.1152/physrev.00043.2021] [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: 11/22/2022] Open
Abstract
The human heart beats over eighty thousand times a day, and the average person's heart may have beaten up to 3 billion times by the age of 80. During the early stages of pregnancy, the heart beat provides the first visual and auditory sign of life of the foetus. Conversely, the first audible sound that the foetus is likely to hear is the heart beat of the mother. How fitting then, that at the "birth" Physiological Reviews the very first article published in 1921 written by Eyster and Meek addressed "The origin and conduction of the heart beat".1 In their insightful review, the authors discussed the landmark discoveries made from the mid-19th century on the electrical function of the heart. Now, a hundred years later, at the start of the next century of Physiological Reviews, an update on the huge progress made in the "exciting" field of cardiac electrophysiology is warranted. Guided by a number of excellent reviews published in Physiological Reviews since 1921 as well as a large body of literature, an overview of the important advancements made on the topic is provided here.
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Affiliation(s)
- Carol Ann Remme
- Amsterdam UMC, location University of Amsterdam, Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
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Claveras Cabezudo A, Feriel Khoualdi A, D’Avanzo N. Computational Prediction of Phosphoinositide Binding to Hyperpolarization-Activated Cyclic-Nucleotide Gated Channels. Front Physiol 2022; 13:859087. [PMID: 35399260 PMCID: PMC8990809 DOI: 10.3389/fphys.2022.859087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 12/31/2022] Open
Abstract
Protein-lipid interactions are key regulators of ion channel function. Numerous ion channels, including hyperpolarization-activated cyclic-nucleotide gated (HCN) channels have been shown to be regulated by phosphoinositides (PIPs), with important implications in cardiac and neuronal function. Specifically, PIPs have been shown to enhance HCN activation. Using computational approaches, we aim to identify potential binding sites for HCN1-PIP interactions. Computational docking and coarse-grained simulations indicate that PIP binding to HCN1 channels is not well coordinated, but rather occurs over a broad surface of charged residues primarily in the HCN-domain, S2 and S3 helices that can be loosely organized in 2 or 3 overlapping clusters. Thus, PIP-HCN1 interactions are more resembling of electrostatic interactions that occur in myristoylated alanine-rich C kinase substrate (MARCKS) proteins, than the specifically coordinated interactions that occur in pleckstrin homology domains (PH domains) or ion channels such as inward rectifier potassium (Kir) channels. Our results also indicate that phosphatidylinositol (PI) interactions with HCN1 are even lower affinity, explaining why unphosphorylated PI have no effect on HCN1 activation unlike phosphorylated PIPs.
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Affiliation(s)
- Ainara Claveras Cabezudo
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, Heidelberg, Germany
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
| | - Asma Feriel Khoualdi
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
| | - Nazzareno D’Avanzo
- Département de Pharmacologie et Physiologie, Université de Montréal, Montréal, QC, Canada
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Ng LCT, Li YX, Van Petegem F, Accili EA. Altered cyclic nucleotide-binding and pore opening in a diseased human HCN4 channel. Biophys J 2022; 121:1166-1183. [PMID: 35219649 PMCID: PMC9034293 DOI: 10.1016/j.bpj.2022.02.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/20/2021] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
A growing number of nonsynonymous mutations in the human HCN4 channel gene, the major component of the funny channel of the sinoatrial node, are associated with disease but how they impact channel structure and function, and, thus, how they result in disease, is not clear for any of them. Here, we study the S672R mutation, in the cyclic nucleotide-binding domain of the channel, which has been associated with an inherited bradycardia in an Italian family. This may be the best studied of all known mutations, yet the underlying molecular and atomistic mechanisms remain unclear and controversial. We combine measurements of binding by isothermal titration calorimetry to a naturally occurring tetramer of the HCN4 C-terminal region with a mathematical model to show that weaker binding of cAMP to the mutant channel contributes to a lower level of facilitation of channel opening at submicromolar ligand concentrations but that, in general, facilitation occurs over a range that is similar between the mutant and wild-type because of enhanced opening of the mutant channel when liganded. We also show that the binding affinity for cGMP, which produces the same maximum facilitation of HCN4 opening as cAMP, is weaker in the mutant HCN4 channel but that, for both wild-type and mutant, high-affinity binding of cGMP occurs in a range of concentrations below 1 μM. Thus, binding of cGMP to the HCN4 channel may be relevant normally in vivo and reduced binding of cGMP, as well as cAMP, to the mutant channel may contribute to the reduced resting heart rate observed in the affected family.
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Affiliation(s)
- Leo C T Ng
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Yue Xian Li
- Department of Mathematics, University of British Columbia, Vancouver, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Eric A Accili
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada.
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Aminu AJ, Petkova M, Atkinson AJ, Yanni J, Morris AD, Simms RT, Chen W, Yin Z, Kuniewicz M, Holda MK, Kuzmin VS, Perde F, Molenaar P, Dobrzynski H. Further insights into the molecular complexity of the human sinus node - The role of 'novel' transcription factors and microRNAs. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:86-104. [PMID: 34004232 DOI: 10.1016/j.pbiomolbio.2021.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 02/06/2023]
Abstract
RESEARCH PURPOSE The sinus node (SN) is the heart's primary pacemaker. Key ion channels (mainly the funny channel, HCN4) and Ca2+-handling proteins in the SN are responsible for its function. Transcription factors (TFs) regulate gene expression through inhibition or activation and microRNAs (miRs) do this through inhibition. There is high expression of macrophages and mast cells within the SN connective tissue. 'Novel'/unexplored TFs and miRs in the regulation of ion channels and immune cells in the SN are not well understood. Using RNAseq and bioinformatics, the expression profile and predicted interaction of key TFs and cell markers with key miRs in the adult human SN vs. right atrial tissue (RA) were determined. PRINCIPAL RESULTS 68 and 60 TFs significantly more or less expressed in the SN vs. RA respectively. Among those more expressed were ISL1 and TBX3 (involved in embryonic development of the SN) and 'novel' RUNX1-2, CEBPA, GLI1-2 and SOX2. These TFs were predicted to regulate HCN4 expression in the SN. Markers for different cells: fibroblasts (COL1A1), fat (FABP4), macrophages (CSF1R and CD209), natural killer (GZMA) and mast (TPSAB1) were significantly more expressed in the SN vs. RA. Interestingly, RUNX1-3, CEBPA and GLI1 also regulate expression of these cells. MiR-486-3p inhibits HCN4 and markers involved in immune response. MAJOR CONCLUSIONS In conclusion, RUNX1-2, CSF1R, TPSAB1, COL1A1 and HCN4 are highly expressed in the SN but not miR-486-3p. Their complex interactions can be used to treat SN dysfunction such as bradycardia. Interestingly, another research group recently reported miR-486-3p is upregulated in blood samples from severe COVID-19 patients who suffer from bradycardia.
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Affiliation(s)
- Abimbola J Aminu
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Maria Petkova
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Andrew J Atkinson
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Joseph Yanni
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Alex D Morris
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Robert T Simms
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Weixuan Chen
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Zeyuan Yin
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom
| | - Marcin Kuniewicz
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland
| | - Mateusz K Holda
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Moscow, Russia
| | - Filip Perde
- National Institute of Legal Medicine, Bucharest, Romania
| | - Peter Molenaar
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia; Cardiovascular Molecular & Therapeutics Translational Research Group, University of Queensland, The Prince Charles Hospital, Brisbane, Australia
| | - Halina Dobrzynski
- The Division of Cardiovascular Sciences, University of Manchester, United Kingdom; Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland.
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f/HCN channels: From a tiny current controlling cardiac pacemaking to a pleiotropic current all over the body. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:1-2. [PMID: 34648827 DOI: 10.1016/j.pbiomolbio.2021.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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A second S4 movement opens hyperpolarization-activated HCN channels. Proc Natl Acad Sci U S A 2021; 118:2102036118. [PMID: 34504015 DOI: 10.1073/pnas.2102036118] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 11/18/2022] Open
Abstract
Rhythmic activity in pacemaker cells, as in the sino-atrial node in the heart, depends on the activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. As in depolarization-activated K+ channels, the fourth transmembrane segment S4 functions as the voltage sensor in hyperpolarization-activated HCN channels. But how the inward movement of S4 in HCN channels at hyperpolarized voltages couples to channel opening is not understood. Using voltage clamp fluorometry, we found here that S4 in HCN channels moves in two steps in response to hyperpolarizations and that the second S4 step correlates with gate opening. We found a mutation in sea urchin HCN channels that separate the two S4 steps in voltage dependence. The E356A mutation in S4 shifts the main S4 movement to positive voltages, but channel opening remains at negative voltages. In addition, E356A reveals a second S4 movement at negative voltages that correlates with gate opening. Cysteine accessibility and molecular models suggest that the second S4 movement opens up an intracellular crevice between S4 and S5 that would allow radial movement of the intracellular ends of S5 and S6 to open HCN channels.
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Benzoni P, Bertoli G, Giannetti F, Piantoni C, Milanesi R, Pecchiari M, Barbuti A, Baruscotti M, Bucchi A. The funny current: Even funnier than 40 years ago. Uncanonical expression and roles of HCN/f channels all over the body. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:189-204. [PMID: 34400215 DOI: 10.1016/j.pbiomolbio.2021.08.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/25/2021] [Accepted: 08/09/2021] [Indexed: 12/25/2022]
Abstract
Discovered some 40 years ago, the If current has since been known as the "pacemaker" current due to its role in the initiation and modulation of the heartbeat and of neuronal excitability. But this is not all, the funny current keeps entertaining the researchers; indeed, several data discovering novel and uncanonical roles of f/HCN channel are quickly accumulating. In the present review, we provide an overview of the expression and cellular functions of HCN/f channels in a variety of systems/organs, and particularly in sour taste transduction, hormones secretion, activation of astrocytes and microglia, inhibition of osteoclastogenesis, renal ammonium excretion, and peristalsis in the gastrointestinal and urine systems. We also analyzed the role of HCN channels in sustaining cellular respiration in mitochondria and their participation to mitophagy under specific conditions. The relevance of HCN currents in undifferentiated cells, and specifically in the control of stem cell cycle and in bioelectrical signals driving left/right asymmetry during zygote development, is also considered. Finally, we present novel data concerning the expression of HCN mRNA in human leukocytes. We can thus conclude that the emerging evidence presented in this review clearly points to an increasing interest and importance of the "funny" current that goes beyond its role in cardiac sinoatrial and neuronal excitability regulation.
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Affiliation(s)
- Patrizia Benzoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Giorgia Bertoli
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Federica Giannetti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Chiara Piantoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy; Present Address: Institute of Neurophysiology, Hannover Medical School, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Raffaella Milanesi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy; Present Address: Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Via Dell'Università 6, 26900, Lodi, Italy
| | - Matteo Pecchiari
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Via L. Mangiagalli 32, 20133, Milan, Italy
| | - Andrea Barbuti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Mirko Baruscotti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Annalisa Bucchi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy.
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Naumova N, Iop L. Bioengineering the Cardiac Conduction System: Advances in Cellular, Gene, and Tissue Engineering for Heart Rhythm Regeneration. Front Bioeng Biotechnol 2021; 9:673477. [PMID: 34409019 PMCID: PMC8365186 DOI: 10.3389/fbioe.2021.673477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023] Open
Abstract
Heart rhythm disturbances caused by different etiologies may affect pediatric and adult patients with life-threatening consequences. When pharmacological therapy is ineffective in treating the disturbances, the implantation of electronic devices to control and/or restore normal heart pacing is a unique clinical management option. Although these artificial devices are life-saving, they display many limitations; not least, they do not have any capability to adapt to somatic growth or respond to neuroautonomic physiological changes. A biological pacemaker could offer a new clinical solution for restoring heart rhythms in the conditions of disorder in the cardiac conduction system. Several experimental approaches, such as cell-based, gene-based approaches, and the combination of both, for the generation of biological pacemakers are currently established and widely studied. Pacemaker bioengineering is also emerging as a technology to regenerate nodal tissues. This review analyzes and summarizes the strategies applied so far for the development of biological pacemakers, and discusses current translational challenges toward the first-in-human clinical application.
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Affiliation(s)
| | - Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Padua, Italy
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Yip D, Accili E. Kinetic modelling of voltage-dependent gating in funny channels. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:182-188. [PMID: 34310984 DOI: 10.1016/j.pbiomolbio.2021.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/12/2021] [Accepted: 07/20/2021] [Indexed: 10/20/2022]
Affiliation(s)
- Delbert Yip
- Department of Cellular and Physiological Sciences, University of British Columbia, Health Sciences Mall, V6T 1Z3, 2350, Canada
| | - Eric Accili
- Department of Cellular and Physiological Sciences, University of British Columbia, Health Sciences Mall, V6T 1Z3, 2350, Canada.
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Porro A, Abbandonato G, Veronesi V, Russo A, Binda A, Antolini L, Granata T, Castellotti B, Marini C, Moroni A, DiFrancesco JC, Rivolta I. Do the functional properties of HCN1 mutants correlate with the clinical features in epileptic patients? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:147-155. [PMID: 34310985 DOI: 10.1016/j.pbiomolbio.2021.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/14/2021] [Accepted: 07/20/2021] [Indexed: 10/20/2022]
Abstract
The altered function of the Hyperpolarization-activated Cyclic-Nucleotide-gated (HCN) ion channels plays an important role in the pathogenesis of epilepsy in humans. In particular, HCN1 missense mutations have been recently identified in patients with different epileptic phenotypes, varying from mild to severe. Their electrophysiological characterization shows that mutated channels can act both with loss-of-function and gain-of-function mechanisms of action, without an evident correlation with the phenotype. In search for a correlation between clinical features and biophysical properties of the mutations, in this work we considered sixteen HCN1 mutations, found in eighteen Early Infantile Epileptic Encephalopathy (EIEE) patients. Statistical analysis did not establish any significant correlation between the clinical parameters and the current properties of the mutant channels. The lack of significance of our results could depend on the small number of mutations analyzed, epilepsy-associated with certainty. With the progressive increase of Next Generation Sequencing in patients with early-onset epilepsy, it is expected that the number of patients with HCN1 mutations will grow steadily. Functional characterization of epilepsy-associated HCN1 mutations remains a fundamental tool for a better understanding of the pathogenetic mechanisms leading to the disease in humans.
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Affiliation(s)
| | | | - Valentina Veronesi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Alberto Russo
- Department of Biosciences, University of Milan, Milan, Italy.
| | - Anna Binda
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Laura Antolini
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Carla Marini
- Department of Child Neuropsychiatry, Children's Hospital, Ancona, Italy.
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy.
| | - Jacopo C DiFrancesco
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Department of Neurology, Epilepsy Center, ASST San Gerardo Hospital, University of Milano- Bicocca, Monza, Italy.
| | - Ilaria Rivolta
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy.
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49
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The HCN channel as a pharmacological target: Why, where, and how to block it. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:173-181. [PMID: 34303730 DOI: 10.1016/j.pbiomolbio.2021.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 06/22/2021] [Accepted: 07/20/2021] [Indexed: 12/19/2022]
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels, expressed in a variety of cell types and in all tissues, control excitation and rhythm. Since their discovery in neurons and cardiac pacemaker cells, they attracted the attention of medicinal chemistry and pharmacology as novel targets to shape (patho)physiological mechanisms. To date, ivabradine represents the first-in-class drug as specific bradycardic agent in cardiac diseases; however, new applications are emerging in parallel with the demonstration of the involvement of different HCN isoforms in central and peripheral nervous system. Hence, the possibility to target specific isoforms represents an attractive development in this field; indeed, HCN1, HCN2 or HCN4 specific blockers have shown promising features in vitro and in vivo, with remarkable pharmacological differences likely depending on the diverse functional role and tissue distribution. Here, we show a recently developed compound with high potency as HCN2-HCN4 blocker; because of its unique profile, this compound may deserve further investigation.
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50
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Saponaro A, Bauer D, Giese MH, Swuec P, Porro A, Gasparri F, Sharifzadeh AS, Chaves-Sanjuan A, Alberio L, Parisi G, Cerutti G, Clarke OB, Hamacher K, Colecraft HM, Mancia F, Hendrickson WA, Siegelbaum SA, DiFrancesco D, Bolognesi M, Thiel G, Santoro B, Moroni A. Gating movements and ion permeation in HCN4 pacemaker channels. Mol Cell 2021; 81:2929-2943.e6. [PMID: 34166608 PMCID: PMC8294335 DOI: 10.1016/j.molcel.2021.05.033] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/12/2021] [Accepted: 05/27/2021] [Indexed: 10/31/2022]
Abstract
The HCN1-4 channel family is responsible for the hyperpolarization-activated cation current If/Ih that controls automaticity in cardiac and neuronal pacemaker cells. We present cryoelectron microscopy (cryo-EM) structures of HCN4 in the presence or absence of bound cAMP, displaying the pore domain in closed and open conformations. Analysis of cAMP-bound and -unbound structures sheds light on how ligand-induced transitions in the channel cytosolic portion mediate the effect of cAMP on channel gating and highlights the regulatory role of a Mg2+ coordination site formed between the C-linker and the S4-S5 linker. Comparison of open/closed pore states shows that the cytosolic gate opens through concerted movements of the S5 and S6 transmembrane helices. Furthermore, in combination with molecular dynamics analyses, the open pore structures provide insights into the mechanisms of K+/Na+ permeation. Our results contribute mechanistic understanding on HCN channel gating, cyclic nucleotide-dependent modulation, and ion permeation.
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Affiliation(s)
- Andrea Saponaro
- Department of Biosciences, University of Milan, Milan, Italy
| | - Daniel Bauer
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - M Hunter Giese
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Paolo Swuec
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | | | | | | | - Antonio Chaves-Sanjuan
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | - Laura Alberio
- Department of Biosciences, University of Milan, Milan, Italy; Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giacomo Parisi
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Gabriele Cerutti
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Kay Hamacher
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Wayne A Hendrickson
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Steven A Siegelbaum
- Department of Neuroscience, Zuckerman Institute, Columbia University, New York, NY, USA
| | - Dario DiFrancesco
- Department of Biosciences, University of Milan, Milan, Italy; Institute of Biophysics-Milano, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Milan, Italy; Pediatric Research Center "Romeo ed Enrica Invernizzi," University of Milan, Milan, Italy
| | - Gerhard Thiel
- Department of Biology, TU-Darmstadt, Darmstadt, Germany
| | - Bina Santoro
- Department of Neuroscience, Zuckerman Institute, Columbia University, New York, NY, USA.
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy; Institute of Biophysics-Milano, Consiglio Nazionale delle Ricerche, Rome, Italy.
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