1
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Uzoigwe CE. Nuclear quantum effects explain chemiosmosis: The power of the proton. Biosystems 2025; 251:105407. [PMID: 39892694 DOI: 10.1016/j.biosystems.2025.105407] [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: 09/09/2024] [Revised: 01/28/2025] [Accepted: 01/29/2025] [Indexed: 02/04/2025]
Abstract
ATP is a universal bio-currency, with chemiosmosis the metabolic mint by which currency is printed. Chemiosmosis leverages a membrane potential and ion gradient, typically a proton gradient, to generate ATP. The current chemiosmotic hypothesis is both cannon and dogma. However, there are obstacles to the unqualified and uncritical acceptance of this model. Intriguingly the proton is sufficiently small to exhibit quantum phenomena of wave-particle duality, often thought the exclusive prerogative of smaller subcellular particles. Evidence shows that chemiosmosis is by necessity critically dependent upon these nuclear quantum effects (NQE) of hydrogen, most notably as a proton. It is well established scientific orthodoxy that protons in water and hydrogen atoms of water molecules exhibit quantum phenomena. The effect is amplified by the hydrogen bonding and juxta-membrane location of protons in mitochondria and chloroplasts. NQE explains the otherwise inexplicable features of chemiosmosis, including the paucity of protons, the rate of proton movement and ATP genesis in otherwise subliminal proton motive forces and thus functionality of alkaliphiles. It also accounts for the efficiencies of chemiosmosis reported at greater than 100% in certain contexts, which violates the second law of thermodynamics under the paradigm of classical physics. Mitochondria may have evolved to exploit quantum biology with notable features such as dimeric ATP synthases adumbrating the first double-slip experiment with the protons. The dramatic global deceleration of mitochondrial chemiosmosis and all cellular function following proton substitution with its heavier isotopes, deuterium and tritium: "deuteruction", is testimony to the primacy of nuclear quantum effects in this Quantum Chemiosmosis. Indeed the speed of evolution itself and its inexorable route to homeothermy may be due to the power of nuclear quantum effects of the smallest nucleus, the proton. The atom that is almost nothing was selected to bring about the most important processes and complex manifestations of life.
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2
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Okochi Y, Jinno Y, Okamura Y. Dimerization is required for the glycosylation of S1-S2 linker of sea urchin voltage-gated proton channel Hv1. Biophys J 2024; 123:4221-4232. [PMID: 39086135 DOI: 10.1016/j.bpj.2024.07.034] [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: 04/03/2024] [Revised: 06/08/2024] [Accepted: 07/25/2024] [Indexed: 08/02/2024] Open
Abstract
Multimerization of ion channels is essential for establishing the ion-selective pathway and tuning the gating regulated by membrane potential, second messengers, and temperature. Voltage-gated proton channel, Hv1, consists of voltage-sensor domain and coiled-coil domain. Hv1 forms dimer, whereas voltage-dependent channel activity is self-contained in monomer unlike many ion channels, which assemble to form ion-conductive pathways among multiple subunits. Dimerization of Hv1 is necessary for cooperative gating, but other roles of dimerization in physiological aspects are still largely unclear. In this study, we show that dimerization of Hv1 takes place in ER. Sea urchin Hv1 (Strongylocentrotus purpuratus Hv1: SpHv1) was glycosylated in the consensus sequence for N-linked glycosylation within the S1-S2 extracellular loop. However, glycosylation was not observed in the monomeric SpHv1 that lacks the coiled-coil domain. A version of mHv1 in which the S1-S2 loop was replaced by that of SpHv1 showed glycosylation and its monomeric form was not glycosylated. Tandem dimer of monomeric SpHv1 underwent glycosylation, suggesting that dimerization of Hv1 is required for glycosylation. Moreover, when monomeric Hv1 has a dilysine motif in the C-terminal end, which is known to act as a retrieval signal from Golgi to ER, prolonging the time of residency in ER, it was glycosylated. Overall, our results suggest that monomeric SpHv1 does not stay long in ER, thereby escaping glycosylation, while the dimerization causes the proteins to stay longer in ER. Thus, the findings highlight the novel significance of dimerization of Hv1: regulation of biogenesis and maturation of the proteins in intracellular compartments.
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Affiliation(s)
- Yoshifumi Okochi
- Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Japan.
| | - Yuka Jinno
- Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yasushi Okamura
- Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
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3
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Tang Y, Wu X, Li J, Li Y, Xu X, Li G, Zhang P, Qin C, Wu LJ, Tang Z, Tian DS. The Emerging Role of Microglial Hv1 as a Target for Immunomodulation in Myelin Repair. Aging Dis 2024; 15:1176-1203. [PMID: 38029392 PMCID: PMC11081154 DOI: 10.14336/ad.2023.1107] [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: 08/17/2023] [Accepted: 11/07/2023] [Indexed: 12/01/2023] Open
Abstract
In the central nervous system (CNS), the myelin sheath ensures efficient interconnection between neurons and contributes to the regulation of the proper function of neuronal networks. The maintenance of myelin and the well-organized subtle process of myelin plasticity requires cooperation among myelin-forming cells, glial cells, and neural networks. The process of cooperation is fragile, and the balance is highly susceptible to disruption by microenvironment influences. Reactive microglia play a critical and complicated role in the demyelination and remyelination process. Recent studies have shown that the voltage-gated proton channel Hv1 is selectively expressed in microglia in CNS, which regulates intracellular pH and is involved in the production of reactive oxygen species, underlying multifaceted roles in maintaining microglia function. This paper begins by examining the molecular mechanisms of demyelination and emphasizes the crucial role of the microenvironment in demyelination. It focuses specifically on the role of Hv1 in myelin repair and its therapeutic potential in CNS demyelinating diseases.
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Affiliation(s)
- Yingxin Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Xuan Wu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Jiarui Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Yuanwei Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Xiaoxiao Xu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Gaigai Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Ping Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Chuan Qin
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhouping Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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4
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Shen R, Roux B, Perozo E. Anionic omega currents from single countercharge mutants in the voltage-sensing domain of Ci-VSP. J Gen Physiol 2024; 156:e202213311. [PMID: 38019193 PMCID: PMC10686229 DOI: 10.1085/jgp.202213311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/08/2023] [Accepted: 10/30/2023] [Indexed: 11/30/2023] Open
Abstract
The S4 segment of voltage-sensing domains (VSDs) directly responds to voltage changes by reorienting within the electric field as a permion. A narrow hydrophobic "gasket" or charge transfer center at the core of most VSDs focuses the electric field into a narrow region and catalyzes the sequential and reversible translocation of S4 positive gating charge residues across the electric field while preventing the permeation of physiological ions. Mutating specific S4 gating charges can cause ionic leak currents through the VSDs. These gating pores or omega currents play important pathophysiological roles in many diseases of excitability. Here, we show that mutating D129, a key countercharge residue in the Ciona intestinalis voltage-sensing phosphatase (Ci-VSP), leads to the generation of unique anionic omega currents. Neutralizing D129 causes a dramatic positive shift of activation, facilitates the formation of a continuous water path through the VSD, and creates a positive electrostatic potential landscape inside the VSD that contributes to its unique anionic selectivity. Increasing the population or dwell time of the conducting state by a high external pH or an engineered Cd2+ bridge markedly increases the current magnitude. Our findings uncover a new role of countercharge residues in the impermeable VSD of Ci-VSP and offer insights into mechanisms of the conduction of anionic omega currents linked to countercharge residue mutations.
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Affiliation(s)
- Rong Shen
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Eduardo Perozo
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
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5
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Sumino A, Sumikama T, Shibata M, Irie K. Voltage sensors of a Na + channel dissociate from the pore domain and form inter-channel dimers in the resting state. Nat Commun 2023; 14:7835. [PMID: 38114487 PMCID: PMC10730821 DOI: 10.1038/s41467-023-43347-3] [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] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 11/07/2023] [Indexed: 12/21/2023] Open
Abstract
Understanding voltage-gated sodium (Nav) channels is significant since they generate action potential. Nav channels consist of a pore domain (PD) and a voltage sensor domain (VSD). All resolved Nav structures in different gating states have VSDs that tightly interact with PDs; however, it is unclear whether VSDs attach to PDs during gating under physiological conditions. Here, we reconstituted three different voltage-dependent NavAb, which is cloned from Arcobacter butzleri, into a lipid membrane and observed their structural dynamics by high-speed atomic force microscopy on a sub-second timescale in the steady state. Surprisingly, VSDs dissociated from PDs in the mutant in the resting state and further dimerized to form cross-links between channels. This dimerization would occur at a realistic channel density, offering a potential explanation for the facilitation of positive cooperativity of channel activity in the rising phase of the action potential.
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Affiliation(s)
- Ayumi Sumino
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, 920-1192, Japan.
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, 920-1192, Japan.
| | - Takashi Sumikama
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, 920-1192, Japan.
| | - Mikihiro Shibata
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, 920-1192, Japan
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsumasa Irie
- Department of Biophysical chemistry School of Pharmaceutical Science, Wakayama Medical University, Wakayama, 640-8156, Japan.
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Chen GL, Li J, Zhang J, Zeng B. To Be or Not to Be an Ion Channel: Cryo-EM Structures Have a Say. Cells 2023; 12:1870. [PMID: 37508534 PMCID: PMC10378246 DOI: 10.3390/cells12141870] [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: 05/23/2023] [Revised: 07/13/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
Ion channels are the second largest class of drug targets after G protein-coupled receptors. In addition to well-recognized ones like voltage-gated Na/K/Ca channels in the heart and neurons, novel ion channels are continuously discovered in both excitable and non-excitable cells and demonstrated to play important roles in many physiological processes and diseases such as developmental disorders, neurodegenerative diseases, and cancer. However, in the field of ion channel discovery, there are an unignorable number of published studies that are unsolid and misleading. Despite being the gold standard of a functional assay for ion channels, electrophysiological recordings are often accompanied by electrical noise, leak conductance, and background currents of the membrane system. These unwanted signals, if not treated properly, lead to the mischaracterization of proteins with seemingly unusual ion-conducting properties. In the recent ten years, the technical revolution of cryo-electron microscopy (cryo-EM) has greatly advanced our understanding of the structures and gating mechanisms of various ion channels and also raised concerns about the pore-forming ability of some previously identified channel proteins. In this review, we summarize cryo-EM findings on ion channels with molecular identities recognized or disputed in recent ten years and discuss current knowledge of proposed channel proteins awaiting cryo-EM analyses. We also present a classification of ion channels according to their architectures and evolutionary relationships and discuss the possibility and strategy of identifying more ion channels by analyzing structures of transmembrane proteins of unknown function. We propose that cross-validation by electrophysiological and structural analyses should be essentially required for determining molecular identities of novel ion channels.
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Affiliation(s)
- Gui-Lan Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou 646000, China
| | - Jian Li
- College of Pharmaceutical Sciences, Gannan Medical University, Ganzhou 341000, China
| | - Jin Zhang
- School of Basic Medical Sciences, Nanchang University, Nanchang 330031, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou 646000, China
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7
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Cong S, Zhang J, Pan F, Pan L, Zhang A, Ma J. Research progress on ion channels and their molecular regulatory mechanisms in the human sperm flagellum. FASEB J 2023; 37:e23052. [PMID: 37352114 DOI: 10.1096/fj.202300756r] [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: 04/17/2023] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 06/25/2023]
Abstract
The ion channels in sperm tail play an important role in triggering key physiological reactions, e.g., progressive motility, hyperactivation, required for successful fertilization. Among them, CatSper and KSper have been shown to be important ion channels for the transport of Ca2+ and K+ . Moreover, the voltage-gated proton channel Hv1, the sperm-specific sodium-hydrogen exchanger (sNHE), the epithelial sodium channel (ENaC), members of the temperature-sensitive TRP channel family, and the cystic fibrosis transmembrane regulator (CFTR) are also found in the flagellum. This review focuses on the latest advances in ion channels located at the flagellum, describes how they affect sperm physiological function, and summarizes some primary mutual regulation mechanism between ion channels, including PH, membrane potential, and cAMP. These ion channels may be promising targets for clinical application in infertility.
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Affiliation(s)
- Shengnan Cong
- Obstetrics and Gynecology Department, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
- Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, P.R. China
| | - Jingjing Zhang
- Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, P.R. China
| | - Feng Pan
- Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, P.R. China
| | - Lianjun Pan
- Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, P.R. China
| | - Aixia Zhang
- Women's Hospital of Nanjing Medical University (Nanjing Maternity and Child Health Care Hospital), Nanjing, P.R. China
| | - Jiehua Ma
- Obstetrics and Gynecology Department, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
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8
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Chaves G, Jardin C, Derst C, Musset B. Voltage-Gated Proton Channels in the Tree of Life. Biomolecules 2023; 13:1035. [PMID: 37509071 PMCID: PMC10377628 DOI: 10.3390/biom13071035] [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: 05/14/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
With a single gene encoding HV1 channel, proton channel diversity is particularly low in mammals compared to other members of the superfamily of voltage-gated ion channels. Nonetheless, mammalian HV1 channels are expressed in many different tissues and cell types where they exert various functions. In the first part of this review, we regard novel aspects of the functional expression of HV1 channels in mammals by differentially comparing their involvement in (1) close conjunction with the NADPH oxidase complex responsible for the respiratory burst of phagocytes, and (2) in respiratory burst independent functions such as pH homeostasis or acid extrusion. In the second part, we dissect expression of HV channels within the eukaryotic tree of life, revealing the immense diversity of the channel in other phylae, such as mollusks or dinoflagellates, where several genes encoding HV channels can be found within a single species. In the last part, a comprehensive overview of the biophysical properties of a set of twenty different HV channels characterized electrophysiologically, from Mammalia to unicellular protists, is given.
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Affiliation(s)
- Gustavo Chaves
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christophe Jardin
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Christian Derst
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Boris Musset
- Center of Physiology, Pathophysiology and Biophysics, The Nuremberg Location, Paracelsus Medical University, 90419 Nuremberg, Germany
- Center of Physiology, Pathophysiology and Biophysics, The Salzburg Location, Paracelsus Medical University, 5020 Salzburg, Austria
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9
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Pinto FM, Odriozola A, Candenas L, Subirán N. The Role of Sperm Membrane Potential and Ion Channels in Regulating Sperm Function. Int J Mol Sci 2023; 24:6995. [PMID: 37108159 PMCID: PMC10138380 DOI: 10.3390/ijms24086995] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/02/2023] [Accepted: 04/05/2023] [Indexed: 04/29/2023] Open
Abstract
During the last seventy years, studies on mammalian sperm cells have demonstrated the essential role of capacitation, hyperactivation and the acrosome reaction in the acquisition of fertilization ability. These studies revealed the important biochemical and physiological changes that sperm undergo in their travel throughout the female genital tract, including changes in membrane fluidity, the activation of soluble adenylate cyclase, increases in intracellular pH and Ca2+ and the development of motility. Sperm are highly polarized cells, with a resting membrane potential of about -40 mV, which must rapidly adapt to the ionic changes occurring through the sperm membrane. This review summarizes the current knowledge about the relationship between variations in the sperm potential membrane, including depolarization and hyperpolarization, and their correlation with changes in sperm motility and capacitation to further lead to the acrosome reaction, a calcium-dependent exocytosis process. We also review the functionality of different ion channels that are present in spermatozoa in order to understand their association with human infertility.
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Affiliation(s)
- Francisco M. Pinto
- Instituto de Investigaciones Químicas, CSIC-University of Sevilla, Avenida Américo Vespucio 49, 41092 Sevilla, Spain;
| | - Ainize Odriozola
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), 48940 Bizkaia, Spain; (A.O.); (N.S.)
- Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain
- MEPRO Medical Reproductive Solutions, 20009 San Sebastian, Spain
| | - Luz Candenas
- Instituto de Investigaciones Químicas, CSIC-University of Sevilla, Avenida Américo Vespucio 49, 41092 Sevilla, Spain;
| | - Nerea Subirán
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), 48940 Bizkaia, Spain; (A.O.); (N.S.)
- Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain
- MEPRO Medical Reproductive Solutions, 20009 San Sebastian, Spain
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10
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El Chemaly A, Jaquet V, Cambet Y, Caillon A, Cherpin O, Balafa A, Krause KH, Demaurex N. Discovery and validation of new Hv1 proton channel inhibitors with onco-therapeutic potential. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119415. [PMID: 36640925 DOI: 10.1016/j.bbamcr.2022.119415] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 01/13/2023]
Abstract
The voltage-gated hydrogen channel Hv1 encoded in humans by the HVCN1 gene is a highly selective proton channel that allows large fluxes of protons across biological membranes. Hv1 form functional dimers of four transmembrane spanning proteins resembling the voltage sensing domain of potassium channels. Each subunit is highly selective for protons and is controlled by changes in the transmembrane voltage and pH gradient. Hv1 is most expressed in phagocytic cells where it sustains NADPH oxidase-dependent bactericidal function and was reported to facilitate antibody production by B cells and to promote the maturation and motility of spermatocytes. Hv1 contributes to neuroinflammation following brain damage and favors cancer progression possibly by extruding protons generated during aerobic glycolysis of cancer cells. Lack of specific Hv1 inhibitors has hampered translation of this knowledge to treat immune, fertility, or malignancy diseases. In this study, we show that the genetic deletion of Hv1 delays tumor development in a mouse model of granulocytic sarcoma and report the discovery and characterization of two novel bioavailable inhibitors of Hv1 channels that we validate by orthogonal assays and electrophysiological recordings.
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Affiliation(s)
- Antoun El Chemaly
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva 1211, Switzerland
| | - Vincent Jaquet
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland; READs unit, University of Geneva, Geneva 1211, Switzerland
| | - Yves Cambet
- READs unit, University of Geneva, Geneva 1211, Switzerland
| | - Aurélie Caillon
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Ophélie Cherpin
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Alexia Balafa
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Karl-Heinz Krause
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva 1211, Switzerland.
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11
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Neal ML, Beier EE, Hossain MM, Boyle A, Zheng J, Kim C, Mhatre-Winters I, Wu LJ, Richardson JR. Voltage-Gated Proton Channel Hv1 Regulates Neuroinflammation and Dopaminergic Neurodegeneration in Parkinson's Disease Models. Antioxidants (Basel) 2023; 12:582. [PMID: 36978830 PMCID: PMC10044828 DOI: 10.3390/antiox12030582] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023] Open
Abstract
Although the precise mechanisms for neurodegeneration in Parkinson's disease (PD) are unknown, evidence suggests that neuroinflammation is a critical factor in the pathogenic process. Here, we sought to determine whether the voltage-gated proton channel, Hv1 (HVCN1), which is expressed in microglia and regulates NADPH oxidase, is associated with dopaminergic neurodegeneration. We utilized data mining to evaluate the mRNA expression of HVCN1 in the brains of PD patients and controls and uncovered increased expression of the gene encoding Hv1, HVCN1, in the brains of PD patients compared to controls, specifically in male PD patients. In an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 4 × 16 mg/kg) mouse model of PD, Hvcn1 gene expression was increased 2-fold in the striatum. MPTP administration to wild-type (WT) mice resulted in a ~65% loss of tyrosine hydroxylase positive neurons (TH+) in the substantia nigra (SN), while a ~39% loss was observed in Hv1 knockout (KO) mice. Comparable neuroprotective effects of Hv1 deficiency were found in a repeated-dose LPS model. Neuroprotection was associated with decreased pro-inflammatory cytokine levels and pro-oxidant factors in both neurotoxicant animal models. These in vivo results were confirmed in primary microglial cultures, with LPS treatment increasing Hvcn1 mRNA levels and Hv1 KO microglia failing to exhibit the LPS-mediated inflammatory response. Conditioned media from Hv1 KO microglia treated with LPS resulted in an attenuated loss of cultured dopamine neuron cell viability compared to WT microglia. Taken together, these data suggest that Hv1 is upregulated and mediates microglial pro-inflammatory cytokine production in parkinsonian models and therefore represents a novel target for neuroprotection.
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Affiliation(s)
- Matthew L. Neal
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Eric E. Beier
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Muhammad M. Hossain
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Alexa Boyle
- Department of Pharmaceutical Sciences, Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, Rootstown, OH 44201, USA
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Chunki Kim
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Isha Mhatre-Winters
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jason R. Richardson
- Department of Environmental Health Sciences, Robert Stempel College of Public Health and Social Work, Florida International University, Miami, FL 33199, USA
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ 08854, USA
- Department of Pharmaceutical Sciences, Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, Rootstown, OH 44201, USA
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12
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Alvear-Arias JJ, Pena-Pichicoi A, Carrillo C, Fernandez M, Gonzalez T, Garate JA, Gonzalez C. Role of voltage-gated proton channel (Hv1) in cancer biology. Front Pharmacol 2023; 14:1175702. [PMID: 37153807 PMCID: PMC10157179 DOI: 10.3389/fphar.2023.1175702] [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: 02/28/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential. The Hv1 channel is key to proton extrusion for maintaining a balanced cytosolic pH. This protein-channel is expressed in a myriad of tissues and cell lineages whose functions vary from producing bioluminescence in dinoflagellates to alkalizing spermatozoa cytoplasm for reproduction, and regulating the respiratory burst for immune system response. It is no wonder that in acidic environments such as the tumor microenvironment, an exacerbated expression and function of this channel has been reported. Indeed, multiple studies have revealed a strong relationship between pH balance, cancer development, and the overexpression of the Hv1 channel, being proposed as a marker for malignancy in cancer. In this review, we present data that supports the idea that the Hv1 channel plays a significant role in cancer by maintaining pH conditions that favor the development of malignancy features in solid tumor models. With the antecedents presented in this bibliographic report, we want to strengthen the idea that the Hv1 proton channel is an excellent therapeutic strategy to counter the development of solid tumors.
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Affiliation(s)
- Juan J. Alvear-Arias
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Antonio Pena-Pichicoi
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Christian Carrillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernandez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Tania Gonzalez
- National Center for Minimally Invasive Surgery, La Habana, Cuba
| | - Jose A. Garate
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia y Vida, Santiago, Chile
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
- *Correspondence: Carlos Gonzalez,
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13
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Papp F, Toombes GES, Pethő Z, Bagosi A, Feher A, Almássy J, Borrego J, Kuki Á, Kéki S, Panyi G, Varga Z. Multiple mechanisms contribute to fluorometry signals from the voltage-gated proton channel. Commun Biol 2022; 5:1131. [PMID: 36289443 PMCID: PMC9606259 DOI: 10.1038/s42003-022-04065-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 09/30/2022] [Indexed: 11/30/2022] Open
Abstract
Voltage-clamp fluorometry (VCF) supplies information about the conformational changes of voltage-gated proteins. Changes in the fluorescence intensity of the dye attached to a part of the protein that undergoes a conformational rearrangement upon the alteration of the membrane potential by electrodes constitute the signal. The VCF signal is generated by quenching and dequenching of the fluorescence as the dye traverses various local environments. Here we studied the VCF signal generation, using the Hv1 voltage-gated proton channel as a tool, which shares a similar voltage-sensor structure with voltage-gated ion channels but lacks an ion-conducting pore. Using mutagenesis and lipids added to the extracellular solution we found that the signal is generated by the combined effects of lipids during movement of the dye relative to the plane of the membrane and by quenching amino acids. Our 3-state model recapitulates the VCF signals of the various mutants and is compatible with the accepted model of two major voltage-sensor movements. Fluorometry signals indicating conformational change in an ion channel are generated by quenching amino acids and lipid effects during movement of the dye relative to the plane of the membrane.
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Affiliation(s)
- Ferenc Papp
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Gilman E. S. Toombes
- grid.94365.3d0000 0001 2297 5165Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 35 Convent Dr., MSC 3701, Bethesda, MD 20892-3701 USA
| | - Zoltán Pethő
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary ,grid.5949.10000 0001 2172 9288Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany
| | - Adrienn Bagosi
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Adam Feher
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - János Almássy
- grid.7122.60000 0001 1088 8582Department of Physiology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Jesús Borrego
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Ákos Kuki
- grid.7122.60000 0001 1088 8582Department of Applied Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Sándor Kéki
- grid.7122.60000 0001 1088 8582Department of Applied Chemistry, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Gyorgy Panyi
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
| | - Zoltan Varga
- grid.7122.60000 0001 1088 8582Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, Debrecen, H-4032 Hungary
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14
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Llanos MA, Ventura C, Martín P, Enrique N, Felice JI, Gavernet L, Milesi V. Novel Dimeric hHv1 Model and Structural Bioinformatic Analysis Reveal an ATP-Binding Site Resulting in a Channel Activating Effect. J Chem Inf Model 2022; 62:3200-3212. [PMID: 35758884 DOI: 10.1021/acs.jcim.1c01396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human voltage-gated proton channel (hHv1) is a highly selective ion channel codified by the HVCN1 gene. It plays a fundamental role in several physiological processes such as innate and adaptive immunity, insulin secretion, and sperm capacitation. Moreover, in humans, a higher hHv1 expression/function has been reported in several types of cancer cells. Here we report a multitemplate homology model of the hHv1 channel, built and refined as a dimer in Rosetta. The model was then subjected to extensive Gaussian accelerated molecular dynamics (GaMD) for enhanced conformational sampling, and representative snapshots were extracted by clustering analysis. Combining different structure- and sequence-based methodologies, we predicted a putative ATP-binding site located on the intracellular portion of the channel. Furthermore, GaMD simulations of the ATP-bound dimeric hHv1 model showed that ATP interacts with a cluster of positively charged residues from the cytoplasmic N and C terminal segments. According to the in silico predictions, we found that 3 mM intracellular ATP significantly increases the H+ current mediated by the hHv1 channel expressed in HEK293 cells and measured by the patch-clamp technique in an inside-out configuration (2.86 ± 0.63 fold over control at +40 mV). When ATP was added on the extracellular side, it was not able to activate the channel supporting the idea that the ATP-binding site resides in the intracellular face of the hHV1 channel. In a physiological and pathophysiological context, this ATP-mediated modulation could integrate the cell metabolic state with the H+ efflux, especially in cells where hHv1 channels are relevant for pH regulation, such as pancreatic β-cells, immune cells, and cancer cells.
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Affiliation(s)
- Manuel A Llanos
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), Fac. de Ciencias Exactas, Universidad Nacional de La Plata. La Plata B1900ADU, Buenos Aires, Argentina
| | - Clara Ventura
- Facultad de Ciencias Exactas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Pedro Martín
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Nicolás Enrique
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Juan I Felice
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Luciana Gavernet
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), Fac. de Ciencias Exactas, Universidad Nacional de La Plata. La Plata B1900ADU, Buenos Aires, Argentina
| | - Verónica Milesi
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
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15
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Delgado-Bermúdez A, Yeste M, Bonet S, Pinart E. A Review on the Role of Bicarbonate and Proton Transporters during Sperm Capacitation in Mammals. Int J Mol Sci 2022; 23:ijms23116333. [PMID: 35683013 PMCID: PMC9180951 DOI: 10.3390/ijms23116333] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/01/2022] [Accepted: 06/05/2022] [Indexed: 12/14/2022] Open
Abstract
Alkalinization of sperm cytosol is essential for plasma membrane hyperpolarization, hyperactivation of motility, and acrosomal exocytosis during sperm capacitation in mammals. The plasma membrane of sperm cells contains different ion channels implicated in the increase of internal pH (pHi) by favoring either bicarbonate entrance or proton efflux. Bicarbonate transporters belong to the solute carrier families 4 (SLC4) and 26 (SLC26) and are currently grouped into Na+/HCO3− transporters and Cl−/HCO3− exchangers. Na+/HCO3− transporters are reported to be essential for the initial and fast entrance of HCO3− that triggers sperm capacitation, whereas Cl−/HCO3− exchangers are responsible for the sustained HCO3− entrance which orchestrates the sequence of changes associated with sperm capacitation. Proton efflux is required for the fast alkalinization of capacitated sperm cells and the activation of pH-dependent proteins; according to the species, this transport can be mediated by Na+/H+ exchangers (NHE) belonging to the SLC9 family and/or voltage-gated proton channels (HVCN1). Herein, we discuss the involvement of each of these channels in sperm capacitation and the acrosome reaction.
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Affiliation(s)
- Ariadna Delgado-Bermúdez
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Marc Yeste
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), ES-08010 Barcelona, Spain
| | - Sergi Bonet
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
| | - Elisabeth Pinart
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain; (A.D.-B.); (M.Y.); (S.B.)
- Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain
- Correspondence: ; Tel.: +34-972-419-514
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16
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Zheng J, Murugan M, Wang L, Wu LJ. Microglial voltage-gated proton channel Hv1 in spinal cord injury. Neural Regen Res 2022; 17:1183-1189. [PMID: 34782552 PMCID: PMC8643068 DOI: 10.4103/1673-5374.327325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/12/2020] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
After spinal cord injury, microglia as the first responders to the lesion display both beneficial and detrimental characteristics. Activated microglia phagocyte and eliminate cell debris, release cytokines to recruit peripheral immune cells to the injury site. Excessively activated microglia can aggravate the secondary damage by producing extravagant reactive oxygen species and pro-inflammatory cytokines. Recent studies demonstrated that the voltage-gated proton channel Hv1 is selectively expressed in microglia and regulates microglial activation upon injury. In mouse models of spinal cord injury, Hv1 deficiency ameliorates microglia activation, resulting in alleviated production of reactive oxygen species and pro-inflammatory cytokines. The reduced secondary damage subsequently decreases neuronal loss and correlates with improved locomotor recovery. This review provides a brief historical perspective of advances in investigating voltage-gated proton channel Hv1 and home in on microglial Hv1. We discuss recent studies on the roles of Hv1 activation in pathophysiological activities of microglia, such as production of NOX-dependent reactive oxygen species, microglia polarization, and tissue acidosis, particularly in the context of spinal cord injury. Further, we highlight the rationale for targeting Hv1 for the treatment of spinal cord injury and related disorders.
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Affiliation(s)
- Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Madhuvika Murugan
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Lingxiao Wang
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Department of Immunology, Mayo Clinic, Rochester, MN, USA
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17
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Jardin C, Ohlwein N, Franzen A, Chaves G, Musset B. The pH-dependent gating of the human voltage-gated proton channel from computational simulations. Phys Chem Chem Phys 2022; 24:9964-9977. [PMID: 35445675 DOI: 10.1039/d1cp05609c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Gating of the voltage-gated proton channel HV1 is strongly controlled by pH. There is evidence that this involves the sidechains of titratable amino acids that change their protonation state with changes of the pH. Despite experimental investigations to identify the amino acids involved in pH sensing only few progress has been made, including one histidine at the cytoplasmic side of the channel that is involved in sensing cellular pH. We have used constant pH molecular dynamics simulations in symmetrical and asymmetrical pH conditions across the membrane to investigate the pH- and ΔpH-dependent gating of the human HV1 channel. Therefore, the pKa of every titratable amino acids has been assessed in single simulations. Our simulations captured initial conformational changes between a deactivated and an activated state of the channel induced solely by changes of the pH. The pH-dependent gating is accompanied by an outward displacement of the three S4 voltage sensing arginines that moves the second arginine past the hydrophobic gasket (HG) which separates the inner and outer pores of the channel. HV1 activation, when outer pH increases, involves amino acids at the extracellular entrance of the channel that extend the network of interactions from the external solution down to the HG. Whereas, amino acids at the cytoplasmic entrance of the channel are involved in activation, when inner pH decreases, and in a network of interactions that extend from the cytoplasm up to the HG.
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Affiliation(s)
- Christophe Jardin
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
| | - Niklas Ohlwein
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany. .,Klinik für Anästhesiologie und operative Intensivmedizin, Universitätklinik der Paracelsus Medizinischen Privatuniversität, Nuremberg, Germany
| | - Arne Franzen
- Institute of Biological Information Processing, Molecular and Cellular Physiology (IBI-1), Forschungszentrum Jülich, Jülich, Germany
| | - Gustavo Chaves
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
| | - Boris Musset
- Klinikum Nürnberg Medical School, CPPB, Institute of Physiology, Pathophysiology and Biophysics, Nuremberg, Germany.
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18
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Orts DJB, Arcisio-Miranda M. Cell glycosaminoglycans content modulates human voltage-gated proton channel (H V 1) gating. FEBS J 2021; 289:2593-2612. [PMID: 34800064 DOI: 10.1111/febs.16290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/01/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022]
Abstract
Voltage-gated proton channels (HV 1) have been found in many mammalian cells and play a crucial role in the immune system, male fertility, and cancer progression. Glycosaminoglycans play a significant role in various aspects of cell physiology, including the modulation of membrane receptors and ion channel function. We present here evidence that mechanosensitivity of the dimeric HV 1 channel transduce changes on cell membrane fluidity related to the defective biosynthesis of chondroitin sulfate and heparan sulfate in Chinese Hamster Ovary (CHO-745) cells into a leftward shift in the activation voltage dependence. This effect was accompanied by an increase in the H+ current, and an acceleration of the activation kinetics, under symmetrical or asymmetrical pH gradient (ΔpH) conditions. Similar gating alterations were evoked by two naturally occurring HV 1 N-terminal truncated isoforms expressed in wild-type CHO-K1 and CHO-745 cells. On three different monomeric HV 1 constructs, no alterations in the biophysical parameters were observed. Moreover, we have shown that HV 1 gating can be modulated by manipulating CHO-K1 cell membrane fluidity. Our results suggest that the defective biosynthesis of chondroitin sulfate and heparan sulfate on CHO-745 cell increases membrane fluidity and allosterically modulates the coupling between voltage- and ΔpH-sensing through the dimeric HV 1 channel.
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Affiliation(s)
- Diego J B Orts
- Departamento de Biofísica, Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Universidade Federal de São Paulo - UNIFESP, Brasil
| | - Manoel Arcisio-Miranda
- Departamento de Biofísica, Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Universidade Federal de São Paulo - UNIFESP, Brasil
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19
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Rangel-Yescas G, Cervantes C, Cervantes-Rocha MA, Suárez-Delgado E, Banaszak AT, Maldonado E, Ramsey IS, Rosenbaum T, Islas LD. Discovery and characterization of H v1-type proton channels in reef-building corals. eLife 2021; 10:e69248. [PMID: 34355697 PMCID: PMC8346283 DOI: 10.7554/elife.69248] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Voltage-dependent proton-permeable channels are membrane proteins mediating a number of important physiological functions. Here we report the presence of a gene encoding Hv1 voltage-dependent, proton-permeable channels in two species of reef-building corals. We performed a characterization of their biophysical properties and found that these channels are fast-activating and modulated by the pH gradient in a distinct manner. The biophysical properties of these novel channels make them interesting model systems. We have also developed an allosteric gating model that provides mechanistic insight into the modulation of voltage-dependence by protons. This work also represents the first functional characterization of any ion channel in scleractinian corals. We discuss the implications of the presence of these channels in the membranes of coral cells in the calcification and pH-regulation processes and possible consequences of ocean acidification related to the function of these channels.
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Affiliation(s)
- Gisela Rangel-Yescas
- Departmento de Fisiología, Facultad of Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Cecilia Cervantes
- Departmento de Fisiología, Facultad of Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miguel A Cervantes-Rocha
- Departmento de Fisiología, Facultad of Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Esteban Suárez-Delgado
- Departmento de Fisiología, Facultad of Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Anastazia T Banaszak
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Ernesto Maldonado
- EvoDevo Research Group, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Ian Scott Ramsey
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, United States
| | - Tamara Rosenbaum
- Departmento of Neurociencia Cognitiva, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Leon D Islas
- Departmento de Fisiología, Facultad of Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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20
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Schaub C, Lee P, Racho-Jansen A, Giovinazzo J, Terra N, Raper J, Thomson R. Coiled-coil binding of the leucine zipper domains of APOL1 is necessary for the open cation channel conformation. J Biol Chem 2021; 297:101009. [PMID: 34331942 PMCID: PMC8446801 DOI: 10.1016/j.jbc.2021.101009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 07/12/2021] [Accepted: 07/23/2021] [Indexed: 11/17/2022] Open
Abstract
Apolipoprotein L-I (APOL1) is a channel-forming effector of innate immunity. The common human APOL1 variant G0 provides protection against infection with certain Trypanosoma and Leishmania parasite species, but it cannot protect against the trypanosomes responsible for human African trypanosomiasis. Human APOL1 variants G1 and G2 protect against human-infective trypanosomes but also confer a higher risk of developing chronic kidney disease. Trypanosome-killing activity is dependent on the ability of APOL1 to insert into membranes at acidic pH and form pH-gated cation channels. We previously mapped the channel’s pore-lining region to the C-terminal domain (residues 332–398) and identified a membrane-insertion domain (MID, residues 177–228) that facilitates acidic pH-dependent membrane insertion. In this article, we further investigate structural determinants of cation channel formation by APOL1. Using a combination of site-directed mutagenesis and targeted chemical modification, our data indicate that the C-terminal heptad-repeat sequence (residues 368–395) is a bona fide leucine zipper domain (ZIP) that is required for cation channel formation as well as lysis of trypanosomes and mammalian cells. Using protein-wide cysteine-scanning mutagenesis, coupled with the substituted cysteine accessibility method, we determined that, in the open channel state, both the N-terminal domain and the C-terminal ZIP domain are exposed on the intralumenal/extracellular side of the membrane and provide evidence that each APOL1 monomer contributes four transmembrane domains to the open cation channel conformation. Based on these data, we propose an oligomeric topology model in which the open APOL1 cation channel is assembled from the coiled-coil association of C-terminal ZIP domains.
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Affiliation(s)
- Charles Schaub
- Department of Biological sciences, Hunter College, City University of New York, USA; The Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York; Vanderbilt University, Nashville, Tennessee, USA
| | - Penny Lee
- Department of Biological sciences, Hunter College, City University of New York, USA; John Jay College, City University of New York, USA
| | - Alisha Racho-Jansen
- Department of Biological sciences, Hunter College, City University of New York, USA
| | - Joe Giovinazzo
- Department of Biological sciences, Hunter College, City University of New York, USA; University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Nada Terra
- Department of Biological sciences, Hunter College, City University of New York, USA; Icahn School of Medicine at Mount Sinai, New York, USA
| | - Jayne Raper
- Department of Biological sciences, Hunter College, City University of New York, USA; The Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York.
| | - Russell Thomson
- Department of Biological sciences, Hunter College, City University of New York, USA.
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21
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Zhao C, Tombola F. Voltage-gated proton channels from fungi highlight role of peripheral regions in channel activation. Commun Biol 2021; 4:261. [PMID: 33637875 PMCID: PMC7910559 DOI: 10.1038/s42003-021-01792-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
Here, we report the identification and characterization of the first proton channels from fungi. The fungal proteins are related to animal voltage-gated Hv channels and are conserved in both higher and lower fungi. Channels from Basidiomycota and Ascomycota appear to be evolutionally and functionally distinct. Representatives from the two phyla share several features with their animal counterparts, including structural organization and strong proton selectivity, but they differ from each other and from animal Hvs in terms of voltage range of activation, pharmacology, and pH sensitivity. The activation gate of Hv channels is believed to be contained within the transmembrane core of the protein and little is known about contributions of peripheral regions to the activation mechanism. Using a chimeragenesis approach, we find that intra- and extracellular peripheral regions are main determinants of the voltage range of activation in fungal channels, highlighting the role of these overlooked components in channel gating.
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Affiliation(s)
- Chang Zhao
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, USA
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA.
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, USA.
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