1
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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:S0006-3495(24)00493-4. [PMID: 39086135 DOI: 10.1016/j.bpj.2024.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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2
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Rodriguez P, Abbondante S, Marshall M, Abdelmeseh J, Tombola F, Pearlman E. An essential role for the Hv1 voltage-gated proton channel in Pseudomonas aeruginosa corneal infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.15.603631. [PMID: 39071375 PMCID: PMC11275807 DOI: 10.1101/2024.07.15.603631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Assembly of NADPH oxidase 2 (NOX2) proteins in neutrophils plays an essential role in controlling microbial infections by producing high levels of reactive oxygen species (ROS). In contrast, the role of the Hv1 voltage-gated proton channel that is required for sustained NOX2 activity is less well characterized. We examined the role of Hv1 in a murine model of blinding Pseudomonas aeruginosa corneal infection and found that in contrast to C57BL/6 mice, Hvcn1 -/- mice exhibit an impaired ability to kill bacteria and regulate disease severity. In vitro , we used a novel Hv1 Inhibitor Flexible (HIF) to block ROS production by human and murine neutrophils and found that HIF inhibits ROS production in a dose-dependent manner following stimulation with PMA or infection with P. aeruginosa . Collectively, these findings demonstrate an important role for Hv1 on controlling bacterial growth in a clinically relevant bacterial infection model.
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3
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Piga M, Varga Z, Feher A, Papp F, Korpos E, Bangera KC, Frlan R, Ilaš J, Dernovšek J, Tomašič T, Zidar N. Identification of a Novel Structural Class of H V1 Inhibitors by Structure-Based Virtual Screening. J Chem Inf Model 2024; 64:4850-4862. [PMID: 38850237 PMCID: PMC11200261 DOI: 10.1021/acs.jcim.4c00240] [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: 02/09/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
The human voltage-gated proton channel, hHV1, is highly expressed in various cell types including macrophages, B lymphocytes, microglia, sperm cells and also in various cancer cells. Overexpression of HV1 has been shown to promote tumor formation by highly metastatic cancer cells, and has been associated with neuroinflammatory diseases, immune response disorders and infertility, suggesting a potential use of hHV1 inhibitors in numerous therapeutic areas. To identify compounds targeting this channel, we performed a structure-based virtual screening on an open structure of the human HV1 channel. Twenty selected virtual screening hits were tested on Chinese hamster ovary (CHO) cells transiently expressing hHV1, with compound 13 showing strong block of the proton current with an IC50 value of 8.5 μM. Biological evaluation of twenty-three additional analogs of 13 led to the discovery of six other compounds that blocked the proton current by more than 50% at 50 μM concentration. This allowed for an investigation of structure-activity relationships. The antiproliferative activity of the selected promising hHV1 inhibitors was investigated in the cell lines MDA-MB-231 and THP-1, where compound 13 inhibited growth with an IC50 value of 9.0 and 8.1 μM, respectively. The identification of a new structural class of HV1 inhibitors contributes to our understanding of the structural requirements for inhibition of this ion channel and opens up the possibility of investigating the role of HV1 inhibitors in various pathological conditions and in cancer therapy.
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Affiliation(s)
- Martina Piga
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Zoltan Varga
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Adam Feher
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Ferenc Papp
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Eva Korpos
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
- HUN-REN−UD
Cell Biology and Signaling Research Group, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Kavya C. Bangera
- Faculty
of Medicine, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Rok Frlan
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Janez Ilaš
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Jaka Dernovšek
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Tihomir Tomašič
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
| | - Nace Zidar
- Faculty
of Pharmacy, University of Ljubljana, Aškerčeva cesta 7, Ljubljana 1000, Slovenia
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4
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Becker S, Swoboda A, Siemer H, Schimmelpfennig S, Sargin S, Shahin V, Schwab A, Najder K. Membrane potential dynamics of C5a-stimulated neutrophil granulocytes. Pflugers Arch 2024; 476:1007-1018. [PMID: 38613695 PMCID: PMC11139730 DOI: 10.1007/s00424-024-02947-8] [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: 07/26/2023] [Revised: 03/13/2024] [Accepted: 03/13/2024] [Indexed: 04/15/2024]
Abstract
Neutrophil granulocytes play a crucial role in host defense against invading pathogens and in inflammatory diseases. The aim of this study was to elucidate membrane potential dynamics during the initial phase of neutrophil activation and its relation to migration and production of reactive oxygen species (ROS). We performed ROS production measurements of neutrophils from healthy C57BL/6J mice after TNFα-priming and/or C5a stimulation. The actin cytoskeleton was visualized with fluorescence microscopy. Furthermore, we combined migration assays and measurements of membrane potential dynamics after stimulating unprimed and/or TNFα-primed neutrophils with C5a. We show that C5a has a concentration-dependent effect on ROS production and chemokinetic migration. Chemokinetic migration and chemotaxis are impaired at C5a concentrations that induce ROS production. The actin cytoskeleton of unstimulated and of ROS-producing neutrophils is not distributed in a polarized way. Inhibition of the phagocytic NADPH oxidase NOX2 with diphenyleneiodonium (DPI) leads to a polarized distribution of the actin cytoskeleton and rescues chemokinetic migration of primed and C5a-stimulated neutrophils. Moreover, C5a evokes a pronounced depolarization of the cell membrane potential by 86.6 ± 4.2 mV starting from a resting membrane potential of -74.3 ± 0.7 mV. The C5a-induced depolarization occurs almost instantaneously (within less than one minute) in contrast to the more gradually developing depolarization induced by PMA (lag time of 3-4 min). This initial depolarization is accompanied by a decrease of the migration velocity. Collectively, our results show that stimulation with C5a evokes parallel changes in membrane potential dynamics, neutrophil ROS production and motility. Notably, the amplitude of membrane potential dynamics is comparable to that of excitable cells.
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Affiliation(s)
- Stina Becker
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Aljoscha Swoboda
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Henrik Siemer
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | | | - Sarah Sargin
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Victor Shahin
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, University Hospital Münster, Münster, Germany.
| | - Karolina Najder
- Institute of Physiology II, University Hospital Münster, Münster, Germany.
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany.
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5
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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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6
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Ayuyan AG, Cherny VV, Chaves G, Musset B, Cohen FS, DeCoursey TE. Interaction with stomatin directs human proton channels into cholesterol-dependent membrane domains. Biophys J 2024:S0006-3495(24)00168-1. [PMID: 38444158 DOI: 10.1016/j.bpj.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/24/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024] Open
Abstract
Many membrane proteins are modulated by cholesterol. Here we report profound effects of cholesterol depletion and restoration on the human voltage-gated proton channel, hHV1, in excised patches but negligible effects in the whole-cell configuration. Despite the presence of a putative cholesterol-binding site, a CARC motif in hHV1, mutation of this motif did not affect cholesterol effects. The murine HV1 lacks a CARC sequence but displays similar cholesterol effects. These results argue against a direct effect of cholesterol on the HV1 protein. However, the data are fully explainable if HV1 preferentially associates with cholesterol-dependent lipid domains, or "rafts." The rafts would be expected to concentrate in the membrane/glass interface and to be depleted from the electrically accessible patch membrane. This idea is supported by evidence that HV1 channels can diffuse between seal and patch membranes when suction is applied. Simultaneous truncation of the large intracellular N and C termini of hHV1 greatly attenuated the cholesterol effect, but C truncation alone did not; this suggests that the N terminus is the region of attachment to lipid domains. Searching for abundant raft-associated proteins led to stomatin. Co-immunoprecipitation experiment results were consistent with hHV1 binding to stomatin. The stomatin-mediated association of HV1 with cholesterol-dependent lipid domains provides a mechanism for cells to direct HV1 to subcellular locations where it is needed, such as the phagosome in leukocytes.
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Affiliation(s)
- Artem G Ayuyan
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois.
| | - Vladimir V Cherny
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois
| | - Gustavo Chaves
- Institut für Physiologie, Pathophysiologie und Biophysik, CPPB, Paracelsus Medical University, Nürnberg, Germany
| | - Boris Musset
- Institut für Physiologie, Pathophysiologie und Biophysik, CPPB, Paracelsus Medical University, Nürnberg, Germany
| | - Fredric S Cohen
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois
| | - Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois.
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7
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DeCoursey TE. Transcendent Aspects of Proton Channels. Annu Rev Physiol 2024; 86:357-377. [PMID: 37931166 PMCID: PMC10938948 DOI: 10.1146/annurev-physiol-042222-023242] [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: 11/08/2023]
Abstract
A handful of biological proton-selective ion channels exist. Some open at positive or negative membrane potentials, others open at low or high pH, and some are light activated. This review focuses on common features that result from the unique properties of protons. Proton conduction through water or proteins differs qualitatively from that of all other ions. Extraordinary proton selectivity is needed to ensure that protons permeate and other ions do not. Proton selectivity arises from a proton pathway comprising a hydrogen-bonded chain that typically includes at least one titratable amino acid side chain. The enormously diverse functions of proton channels in disparate regions of the phylogenetic tree can be summarized by considering the chemical and electrical consequences of proton flux across membranes. This review discusses examples of cells in which proton efflux serves to increase pHi, decrease pHo, control the membrane potential, generate action potentials, or compensate transmembrane movement of electrical charge.
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Affiliation(s)
- Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, Illinois, USA;
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8
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Zhao C, Webster PD, De Angeli A, Tombola F. Mechanically-primed voltage-gated proton channels from angiosperm plants. Nat Commun 2023; 14:7515. [PMID: 37980353 PMCID: PMC10657467 DOI: 10.1038/s41467-023-43280-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/06/2023] [Indexed: 11/20/2023] Open
Abstract
Voltage-gated and mechanically-gated ion channels are distinct classes of membrane proteins that conduct ions across gated pores and are turned on by electrical or mechanical stimuli, respectively. Here, we describe an Hv channel (a.k.a voltage-dependent H+ channel) from the angiosperm plant A. thaliana that gates with a unique modality as it is turned on by an electrical stimulus only after exposure to a mechanical stimulus, a process that we call priming. The channel localizes in the vascular tissue and has homologs in vascular plants. We find that mechanical priming is not required for activation of non-angiosperm Hvs. Guided by AI-generated structural models of plant Hv homologs, we identify a set of residues playing a crucial role in mechanical priming. We propose that Hvs from angiosperm plants require priming because of a network of hydrophilic/charged residues that locks the channels in a silent resting conformation. Mechanical stimuli destabilize the network allowing the conduction pathway to turn on. In contrast to many other channels and receptors, Hv proteins are not thought to possess mechanisms such as inactivation or desensitization. Our findings demonstrate that angiosperm Hv channels are electrically silent until a mechanical stimulation turns on their voltage-dependent activity.
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Affiliation(s)
- Chang Zhao
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
| | - Parker D Webster
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
| | - Alexis De Angeli
- IPSiM, University of Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France.
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA.
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9
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Song Z, Bhattacharya S, Clemens RA, Dinauer MC. Molecular regulation of neutrophil swarming in health and disease: Lessons from the phagocyte oxidase. iScience 2023; 26:108034. [PMID: 37854699 PMCID: PMC10579437 DOI: 10.1016/j.isci.2023.108034] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023] Open
Abstract
Neutrophil swarming is a complex coordinated process in which neutrophils sensing pathogen or damage signals are rapidly recruited to sites of infections or injuries. This process involves cooperation between neutrophils where autocrine and paracrine positive-feedback loops, mediated by receptor/ligand pairs including lipid chemoattractants and chemokines, amplify localized recruitment of neutrophils. This review will provide an overview of key pathways involved in neutrophil swarming and then discuss the cell intrinsic and systemic mechanisms by which NADPH oxidase 2 (NOX2) regulates swarming, including modulation of calcium signaling, inflammatory mediators, and the mobilization and production of neutrophils. We will also discuss mechanisms by which altered neutrophil swarming in disease may contribute to deficient control of infections and/or exuberant inflammation. Deeper understanding of underlying mechanisms controlling neutrophil swarming and how neutrophil cooperative behavior can be perturbed in the setting of disease may help to guide development of tools for diagnosis and precision medicine.
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Affiliation(s)
- Zhimin Song
- Guangzhou National Laboratory, Guangzhou 510320, Guangdong Province, China
| | - Sourav Bhattacharya
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Regina A. Clemens
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Mary C. Dinauer
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
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10
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Grahn E, Kaufmann SV, Askarova M, Ninov M, Welp LM, Berger TK, Urlaub H, Kaupp UB. Control of intracellular pH and bicarbonate by CO 2 diffusion into human sperm. Nat Commun 2023; 14:5395. [PMID: 37669933 PMCID: PMC10480191 DOI: 10.1038/s41467-023-40855-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 08/14/2023] [Indexed: 09/07/2023] Open
Abstract
The reaction of CO2 with H2O to form bicarbonate (HCO3-) and H+ controls sperm motility and fertilization via HCO3--stimulated cAMP synthesis. A complex network of signaling proteins participates in this reaction. Here, we identify key players that regulate intracellular pH (pHi) and HCO3- in human sperm by quantitative mass spectrometry (MS) and kinetic patch-clamp fluorometry. The resting pHi is set by amiloride-sensitive Na+/H+ exchange. The sperm-specific putative Na+/H+ exchanger SLC9C1, unlike its sea urchin homologue, is not gated by voltage or cAMP. Transporters and channels implied in HCO3- transport are not detected, and may be present at copy numbers < 10 molecules/sperm cell. Instead, HCO3- is produced by diffusion of CO2 into cells and readjustment of the CO2/HCO3-/H+ equilibrium. The proton channel Hv1 may serve as a unidirectional valve that blunts the acidification ensuing from HCO3- synthesis. This work provides a new framework for the study of male infertility.
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Affiliation(s)
- Elena Grahn
- Max Planck Institute for Neurobiology of Behavior-caesar, Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - Svenja V Kaufmann
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Malika Askarova
- Max Planck Institute for Neurobiology of Behavior-caesar, Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - Momchil Ninov
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Am Fassberg 11, 37077, Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
| | - Luisa M Welp
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Am Fassberg 11, 37077, Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
| | - Thomas K Berger
- Max Planck Institute for Neurobiology of Behavior-caesar, Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstrasse 1-2, 35037, Marburg, Germany.
| | - Henning Urlaub
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry, Am Fassberg 11, 37077, Göttingen, Germany.
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.
- Cluster of Excellence, Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC), University of Göttingen, Göttingen, Germany.
| | - U Benjamin Kaupp
- Max Planck Institute for Neurobiology of Behavior-caesar, Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
- Life & Medical Sciences Institute (LIMES), University Bonn, Carl-Troll-Strasse 31, 53115, Bonn, Germany.
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11
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Shen Y, Luo Y, Liao P, Zuo Y, Jiang R. Role of the Voltage-Gated Proton Channel Hv1 in Nervous Systems. Neurosci Bull 2023; 39:1157-1172. [PMID: 37029856 PMCID: PMC10313628 DOI: 10.1007/s12264-023-01053-6] [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: 10/12/2022] [Accepted: 02/20/2023] [Indexed: 04/09/2023] Open
Abstract
Hv1 is the only voltage-gated proton-selective channel in mammalian cells. It contains a conserved voltage-sensor domain, shared by a large class of voltage-gated ion channels, but lacks a pore domain. Its primary role is to extrude protons from the cytoplasm upon pH reduction and membrane depolarization. The best-known function of Hv1 is the regulation of cytosolic pH and the nicotinamide adenine dinucleotide phosphate oxidase-dependent production of reactive oxygen species. Accumulating evidence indicates that Hv1 is expressed in nervous systems, in addition to immune cells and others. Here, we summarize the molecular properties, distribution, and physiological functions of Hv1 in the peripheral and central nervous systems. We describe the recently discovered functions of Hv1 in various neurological diseases, including brain or spinal cord injury, ischemic stroke, demyelinating diseases, and pain. We also summarize the current advances in the discovery and application of Hv1-targeted small molecules in neurological diseases. Finally, we discuss the current limitations of our understanding of Hv1 and suggest future research directions.
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Affiliation(s)
- Yu Shen
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Yuncheng Luo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Ping Liao
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China
| | - Ruotian Jiang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China.
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, 610000, China.
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12
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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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13
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Szanto TG, Feher A, Korpos E, Gyöngyösi A, Kállai J, Mészáros B, Ovari K, Lányi Á, Panyi G, Varga Z. 5-Chloro-2-Guanidinobenzimidazole (ClGBI) Is a Non-Selective Inhibitor of the Human H V1 Channel. Pharmaceuticals (Basel) 2023; 16:ph16050656. [PMID: 37242439 DOI: 10.3390/ph16050656] [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: 03/22/2023] [Revised: 04/13/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
5-chloro-2-guanidinobenzimidazole (ClGBI), a small-molecule guanidine derivative, is a known effective inhibitor of the voltage-gated proton (H+) channel (HV1, Kd ≈ 26 μM) and is widely used both in ion channel research and functional biological assays. However, a comprehensive study of its ion channel selectivity determined by electrophysiological methods has not been published yet. The lack of selectivity may lead to incorrect conclusions regarding the role of hHv1 in physiological or pathophysiological responses in vitro and in vivo. We have found that ClGBI inhibits the proliferation of lymphocytes, which absolutely requires the functioning of the KV1.3 channel. We, therefore, tested ClGBI directly on hKV1.3 using a whole-cell patch clamp and found an inhibitory effect similar in magnitude to that seen on hHV1 (Kd ≈ 72 μM). We then further investigated ClGBI selectivity on the hKV1.1, hKV1.4-IR, hKV1.5, hKV10.1, hKV11.1, hKCa3.1, hNaV1.4, and hNaV1.5 channels. Our results show that, besides HV1 and KV1.3, all other off-target channels were inhibited by ClGBI, with Kd values ranging from 12 to 894 μM. Based on our comprehensive data, ClGBI has to be considered a non-selective hHV1 inhibitor; thus, experiments aiming at elucidating the significance of these channels in physiological responses have to be carefully evaluated.
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Affiliation(s)
- Tibor G Szanto
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Adam Feher
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Eva Korpos
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Adrienn Gyöngyösi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Judit Kállai
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Beáta Mészáros
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Krisztian Ovari
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Árpád Lányi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Zoltan Varga
- Department of Biophysics & Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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14
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Hernandez-Espinosa DR, Gale JR, Scrabis MG, Aizenman E. Microglial reprogramming by Hv1 antagonism protects neurons from inflammatory and glutamate toxicity. J Neurochem 2023; 165:29-54. [PMID: 36625847 PMCID: PMC10106429 DOI: 10.1111/jnc.15760] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/28/2022] [Accepted: 01/02/2023] [Indexed: 01/11/2023]
Abstract
Although the precise mechanisms determining the neurotoxic or neuroprotective activation phenotypes in microglia remain poorly characterized, metabolic changes in these cells appear critical for these processes. As cellular metabolism can be tightly regulated by changes in intracellular pH, we tested whether pharmacological targeting of the microglial voltage-gated proton channel 1 (Hv1), an important regulator of intracellular pH, is critical for activated microglial reprogramming. Using a mouse microglial cell line and mouse primary microglia cultures, either alone, or co-cultured with rat cerebrocortical neurons, we characterized in detail the microglial activation profile in the absence and presence of Hv1 inhibition. We observed that activated microglia neurotoxicity was mainly attributable to the release of tumor necrosis factor alpha, reactive oxygen species, and zinc. Strikingly, pharmacological inhibition of Hv1 largely abrogated inflammatory neurotoxicity not only by reducing the production of cytotoxic mediators but also by promoting neurotrophic molecule production and restraining excessive phagocytic activity. Importantly, the Hv1-sensitive change from a pro-inflammatory to a neuroprotective phenotype was associated with metabolic reprogramming, particularly via a boost in NADH availability and a reduction in lactate. Most critically, Hv1 antagonism not only reduced inflammatory neurotoxicity but also promoted microglia-dependent neuroprotection against a separate excitotoxic injury. Our results strongly suggest that Hv1 blockers may provide an important therapeutic tool against a wide range of inflammatory neurodegenerative disorders.
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Affiliation(s)
- Diego R Hernandez-Espinosa
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jenna R Gale
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Mia G Scrabis
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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15
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Cozzolino M, Gyöngyösi A, Korpos E, Gogolak P, Naseem MU, Kállai J, Lanyi A, Panyi G. The Voltage-Gated Hv1 H+ Channel Is Expressed in Tumor-Infiltrating Myeloid-Derived Suppressor Cells. Int J Mol Sci 2023; 24:ijms24076216. [PMID: 37047188 PMCID: PMC10094655 DOI: 10.3390/ijms24076216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Myeloid-derived suppressor cells (MDSCs) are key determinants of the immunosuppressive microenvironment in tumors. As ion channels play key roles in the physiology/pathophysiology of immune cells, we aimed at studying the ion channel repertoire in tumor-derived polymorphonuclear (PMN-MDSC) and monocytic (Mo-MDSC) MDSCs. Subcutaneous tumors in mice were induced by the Lewis lung carcinoma cell line (LLC). The presence of PMN-MDSC (CD11b+/Ly6G+) and Mo-MDSCs (CD11b+/Ly6C+) in the tumor tissue was confirmed using immunofluorescence microscopy and cells were identified as CD11b+/Ly6G+ PMN-MDSCs and CD11b+/Ly6C+/F4/80−/MHCII− Mo-MDSCs using flow cytometry and sorting. The majority of the myeloid cells infiltrating the LLC tumors were PMN-MDSC (~60%) as compared to ~10% being Mo-MDSCs. We showed that PMN- and Mo-MDSCs express the Hv1 H+ channel both at the mRNA and at the protein level and that the biophysical and pharmacological properties of the whole-cell currents recapitulate the hallmarks of Hv1 currents: ~40 mV shift in the activation threshold of the current per unit change in the extracellular pH, high H+ selectivity, and sensitivity to the Hv1 inhibitor ClGBI. As MDSCs exert immunosuppression mainly by producing reactive oxygen species which is coupled to Hv1-mediated H+ currents, Hv1 might be an attractive target for inhibition of MDSCs in tumors.
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Affiliation(s)
- Marco Cozzolino
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.C.); (E.K.); (M.U.N.)
| | - Adrienn Gyöngyösi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (A.G.); (P.G.); (J.K.); (A.L.)
| | - Eva Korpos
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.C.); (E.K.); (M.U.N.)
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Peter Gogolak
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (A.G.); (P.G.); (J.K.); (A.L.)
| | - Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.C.); (E.K.); (M.U.N.)
| | - Judit Kállai
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (A.G.); (P.G.); (J.K.); (A.L.)
- ELKH-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Arpad Lanyi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (A.G.); (P.G.); (J.K.); (A.L.)
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.C.); (E.K.); (M.U.N.)
- Correspondence: ; Tel.: +36-52-352201
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16
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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: 5.0] [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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17
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Zhao R, Lopez B, Schwingshackl A, Goldstein SA. Protection from acute lung injury by a peptide designed to inhibit the voltage-gated proton channel. iScience 2022; 26:105901. [PMID: 36660473 PMCID: PMC9843441 DOI: 10.1016/j.isci.2022.105901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 12/06/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022] Open
Abstract
There are no targeted medical therapies for Acute Lung Injury (ALI) or its most severe form acute respiratory distress syndrome (ARDS). Infections are the most common cause of ALI/ARDS and these disorders present clinically with alveolar inflammation and barrier dysfunction due to the influx of neutrophils and inflammatory mediator secretion. We designed the C6 peptide to inhibit voltage-gated proton channels (Hv1) and demonstrated that it suppressed the release of reactive oxygen species (ROS) and proteases from neutrophils in vitro. We now show that intravenous C6 counteracts bacterial lipopolysaccharide (LPS)-induced ALI in mice, and suppresses the accumulation of neutrophils, ROS, and proinflammatory cytokines in bronchoalveolar lavage fluid. Confirming the salutary effects of C6 are via Hv1, genetic deletion of the channel similarly protects mice from LPS-induced ALI. This report reveals that Hv1 is a key regulator of ALI, that Hv1 is a druggable target, and that C6 is a viable agent to treat ALI/ARDS.
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Benjamin Lopez
- Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andreas Schwingshackl
- Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA 90095, USA,Corresponding author
| | - Steve A.N. Goldstein
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA,Corresponding author
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18
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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: 0] [Impact Index Per Article: 0] [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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19
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Valenta H, Dupré-Crochet S, Abdesselem M, Bizouarn T, Baciou L, Nüsse O, Deniset-Besseau A, Erard M. Consequences of the constitutive NOX2 activity in living cells: Cytosol acidification, apoptosis, and localized lipid peroxidation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119276. [PMID: 35489654 DOI: 10.1016/j.bbamcr.2022.119276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 03/19/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
The phagocyte NADPH oxidase (NOX2) is a key enzyme of the innate immune system generating superoxide anions (O2•-), precursors of reactive oxygen species. The NOX2 protein complex is composed of six subunits: two membrane proteins (gp91phox and p22phox) forming the catalytic core, three cytosolic proteins (p67phox, p47phox and p40phox) and a small GTPase Rac. The sophisticated activation mechanism of the NADPH oxidase relies on the assembly of cytosolic subunits with the membrane-bound components. A chimeric protein, called 'Trimera', composed of the essential domains of the cytosolic proteins p47phox (aa 1-286), p67phox (aa 1-212) and full-length Rac1Q61L, enables a constitutive and robust NOX2 activity in cells without the need of any stimulus. We employed Trimera as a single activating protein of the phagocyte NADPH oxidase in living cells and examined the consequences on the cell physiology of this continuous and long-term NOX activity. We showed that the sustained high level of NOX activity causes acidification of the intracellular pH, triggers apoptosis and leads to local peroxidation of lipids in the membrane. These local damages to the membrane correlate with the strong tendency of the Trimera to clusterize in the plasma membrane observed by FRET-FLIM microscopy.
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Affiliation(s)
- Hana Valenta
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Sophie Dupré-Crochet
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Mouna Abdesselem
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Tania Bizouarn
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Laura Baciou
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Oliver Nüsse
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Ariane Deniset-Besseau
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France
| | - Marie Erard
- Institut de Chimie Physique, UMR8000, Université Paris-Saclay, CNRS, 91405 Orsay, France.
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20
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Cao Z, Zhao M, Sun H, Hu L, Chen Y, Fan Z. Roles of mitochondria in neutrophils. Front Immunol 2022; 13:934444. [PMID: 36081497 PMCID: PMC9447286 DOI: 10.3389/fimmu.2022.934444] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/19/2022] [Indexed: 01/25/2023] Open
Abstract
Neutrophils are the most abundant leukocyte in human blood. They are critical for fighting infections and are involved in inflammatory diseases. Mitochondria are indispensable for eukaryotic cells, as they control the biochemical processes of respiration and energy production. Mitochondria in neutrophils have been underestimated since glycolysis is a major metabolic pathway for fuel production in neutrophils. However, several studies have shown that mitochondria are greatly involved in multiple neutrophil functions as well as neutrophil-related diseases. In this review, we focus on how mitochondrial components, metabolism, and related genes regulate neutrophil functions and relevant diseases.
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Affiliation(s)
- Ziming Cao
- Department of Immunology, School of Medicine, UConn Health, Farmington, CT, United States
| | - Meng Zhao
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States,Department of Microbiology and Immunology, University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Hao Sun
- Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - Liang Hu
- Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yunfeng Chen
- Department of Biochemistry and Molecular Biology and Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, CT, United States,*Correspondence: Zhichao Fan,
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21
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NADPH Oxidases in Pain Processing. Antioxidants (Basel) 2022; 11:antiox11061162. [PMID: 35740059 PMCID: PMC9219759 DOI: 10.3390/antiox11061162] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 11/21/2022] Open
Abstract
Inflammation or injury to the somatosensory nervous system may result in chronic pain conditions, which affect millions of people and often cause major health problems. Emerging lines of evidence indicate that reactive oxygen species (ROS), such as superoxide anion or hydrogen peroxide, are produced in the nociceptive system during chronic inflammatory and neuropathic pain and act as specific signaling molecules in pain processing. Among potential ROS sources in the somatosensory system are NADPH oxidases, a group of electron-transporting transmembrane enzymes whose sole function seems to be the generation of ROS. Interestingly, the expression and relevant function of the Nox family members Nox1, Nox2, and Nox4 in various cells of the nociceptive system have been demonstrated. Studies using knockout mice or specific knockdown of these isoforms indicate that Nox1, Nox2, and Nox4 specifically contribute to distinct signaling pathways in chronic inflammatory and/or neuropathic pain states. As selective Nox inhibitors are currently being developed and investigated in various physiological and pathophysiological settings, targeting Nox1, Nox2, and/or Nox4 could be a novel strategy for the treatment of chronic pain. Here, we summarize the distinct roles of Nox1, Nox2, and Nox4 in inflammatory and neuropathic processing and discuss the effectiveness of currently available Nox inhibitors in the treatment of chronic pain conditions.
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22
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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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23
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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: 3.0] [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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24
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Coe D, Poobalasingam T, Fu H, Bonacina F, Wang G, Morales V, Moregola A, Mitro N, Cheung KC, Ward EJ, Nadkarni S, Aksentijevic D, Bianchi K, Norata GD, Capasso M, Marelli-Berg FM. Loss of hydrogen voltage-gated channel-1 expression reveals heterogeneous metabolic adaptation to intracellular acidification by T-cells. JCI Insight 2022; 7:147814. [PMID: 35472029 PMCID: PMC9220931 DOI: 10.1172/jci.insight.147814] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
Hvcn1 is a voltage-gated proton channel, which reduces cytosol acidification and facilitates the production of reactive oxygen species (ROS). The increased expression of this channel in some cancers, has led to proposing Hvcn1 antagonists as potential therapeutics.While its role in most leukocytes has been studied in-depth, the function of Hvcn1 in T-cells remains poorly defined. We show that HVCN1 plays a non-redundant role in protecting naïve T-cells from intracellular acidification during priming. Despite sharing overall functional impairment in vivo and in vitro, Hvcn1-deficient CD4+ and CD8+ T-cells display profound differences during the transition from naïve to primed T-cells, including in the preservation of TCR signaling, cellular division and death. These selective features result, at least in part, from a substantially different metabolic response to intracellular acidification associated with priming. While Hvcn1-deficient naïve CD4+ T-cells reprogram to rescue the glycolytic pathway, naïve CD8+ T-cells, which express high levels of this channel in the mitochondria, respond by metabolically compensating mitochondrial dysfunction, at least in part via AMPK activation.These observations imply heterogeneity between adaptation of naïve CD4+ and CD8+ T-cells to intracellular acidification during activation.
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Affiliation(s)
- David Coe
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | | | - Hongmei Fu
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Fabrizia Bonacina
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Guosu Wang
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Valle Morales
- Center for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Annalisa Moregola
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Nico Mitro
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | | | - Eleanor J Ward
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Suchita Nadkarni
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | - Dunja Aksentijevic
- William Harvey Research Institute, Queen Mary University of London, London, United Kingdom
| | | | - Giuseppe Danilo Norata
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
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25
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Pang H, Li J, Li SJ. Role of the voltage-gated proton channel Hv1 in insulin secretion, glucose homeostasis, and obesity. J Physiol Biochem 2022; 78:593-601. [PMID: 35353324 DOI: 10.1007/s13105-022-00891-8] [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: 10/15/2020] [Accepted: 03/11/2022] [Indexed: 10/18/2022]
Abstract
Diabetes is characterized by an absolutely inadequate insulin secretion (type 1 diabetes mellitus) or a relative deficit in insulin secretion due to insulin resistance (type 2 diabetes mellitus), both of which result in elevated blood glucose. Understanding the molecular mechanisms underlying the pathophysiology of diabetes could lead to the development of new therapeutic approaches. The voltage-gated proton channel Hv1 is an ion channel with specific selectivity for protons, which is regulated by membrane potential and intracellular pH. Recently, our studies showed that Hv1 is expressed in β cells of the endocrine pancreas. Knockout of Hv1 reduces insulin secretion and results in hyperglycemia and glucose intolerance, but not insulin resistance. Furthermore, knockout of Hv1 leads to diet-induced obesity due to inflammation and hepatic steatosis. Increasing evidence suggests that Hv1 plays a pivotal role in glucose homeostasis and lipid metabolism. This review aims to summarize advances made so far in our understanding of the roles of Hv1 in the regulation of insulin secretion in β cells, glucose homeostasis, and obesity.
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Affiliation(s)
- Huimin Pang
- Department of Biophysics, School of Physics, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, People's Republic of China
| | - Jinwen Li
- Department of Biophysics, School of Physics, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, People's Republic of China
| | - Shu Jie Li
- Department of Biophysics, School of Physics, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, People's Republic of China.
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26
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Stratmann AEP, Wohlgemuth L, Erber ME, Bernhard S, Hug S, Fauler M, Vidoni L, Mohamed AOK, Thomaß BD, Münnich F, Stukan L, Föhr KJ, Mannes M, Huber-Lang MS, Messerer DAC. Simultaneous Measurement of Changes in Neutrophil Granulocyte Membrane Potential, Intracellular pH, and Cell Size by Multiparametric Flow Cytometry. Biomedicines 2021; 9:1504. [PMID: 34829733 PMCID: PMC8614908 DOI: 10.3390/biomedicines9111504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/10/2023] Open
Abstract
Neutrophils provide rapid and efficient defense mechanisms against invading pathogens. Upon stimulation with proinflammatory mediators, including complement factors and bacterial peptides, neutrophils respond with changes in their membrane potential, intracellular pH, and cellular size. This study provides an approach to quantify these important changes simultaneously using multiparametric flow cytometry, thereby revealing a typical sequence of neutrophil activation consisting of depolarization, alkalization, and increase in cellular size. Additionally, the time resolution of the flow cytometric measurement is improved in order to allow changes that occur within seconds to be monitored, and thus to enhance the kinetic analysis of the neutrophil response. The method is appropriate for the reliable semiquantitative detection of small variations with respect to an increase, no change, and decrease in those parameters as demonstrated by the screening of various proinflammatory mediators. As a translational outlook, the findings are put into context in inflammatory conditions in vitro as well as in a clinically relevant whole blood model of endotoxemia. Taken together, the multiparametric analysis of neutrophil responsiveness regarding depolarization, alkalization, and changes in cellular size may contribute to a better understanding of neutrophils in health and disease, thus potentially yielding innovative mechanistic insights and possible novel diagnostic and/or prognostic approaches.
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Affiliation(s)
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Maike Elisabeth Erber
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Bernhard
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Hug
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
| | - Laura Vidoni
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Adam Omar Khalaf Mohamed
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Bertram Dietrich Thomaß
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Frederik Münnich
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Laura Stukan
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Marco Mannes
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Markus Stefan Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
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27
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Droste A, Chaves G, Stein S, Trzmiel A, Schweizer M, Karl H, Musset B. Zinc accelerates respiratory burst termination in human PMN. Redox Biol 2021; 47:102133. [PMID: 34562872 PMCID: PMC8476447 DOI: 10.1016/j.redox.2021.102133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/09/2021] [Accepted: 09/12/2021] [Indexed: 11/25/2022] Open
Abstract
The respiratory burst of phagocytes is essential for human survival. Innate immune defence against pathogens relies strongly on reactive oxygen species (ROS) production by the NADPH oxidase (NOX2). ROS kill pathogens while the translocation of electrons across the plasma membrane via NOX2 depolarizes the cell. Simultaneously, protons are released into the cytosol. Here, we compare freshly isolated human polymorphonuclear leukocytes (PMN) to the granulocytes-like cell line PLB 985. We are recording ROS production while inhibiting the charge compensating and pH regulating voltage-gated proton channel (HV1). The data suggests that human PMN and the PLB 985 generate ROS via a general mechanism, consistent of NOX2 and HV1. Additionally, we advanced a mathematical model based on the biophysical properties of NOX2 and HV1. Our results strongly suggest the essential interconnection of HV1 and NOX2 during the respiratory burst of phagocytes. Zinc chelation during the time course of the experiments postulates that zinc leads to an irreversible termination of the respiratory burst over time. Flow cytometry shows cell death triggered by high zinc concentrations and PMA. Our data might help to elucidate the complex interaction of proteins during the respiratory burst and contribute to decipher its termination.
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Affiliation(s)
- Annika Droste
- Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Nuremberg, Germany; Department of Gynecology and Obstetrics, Johannes Gutenberg University, Mainz, Germany
| | - Gustavo Chaves
- Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Nuremberg, Germany
| | - Stefan Stein
- Flow Cytometry Unit, Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Germany
| | - Annette Trzmiel
- Flow Cytometry Unit, Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Germany
| | - Matthias Schweizer
- Federal Institute for Vaccines and Biomedicines, Paul-Ehrlich-Institut, Langen, Germany
| | - Hubert Karl
- Department efi, Technische Hochschule Nürnberg Georg Simon Ohm, Nuremberg, Germany
| | - Boris Musset
- Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Nuremberg, Germany; Center of Physiology, Pathophysiology and Biophysics, Paracelsus Medical University, Salzburg, Austria.
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28
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Hawkins P, Sya J, Hup NK, Murphy MP, McElvaney NG, Reeves EP. Alpha-1 Antitrypsin Augmentation Inhibits Proteolysis of Neutrophil Membrane Voltage-Gated Proton Channel-1 in Alpha-1 Deficient Individuals. ACTA ACUST UNITED AC 2021; 57:medicina57080814. [PMID: 34441020 PMCID: PMC8398194 DOI: 10.3390/medicina57080814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022]
Abstract
Background and Objectives: Alpha-1 antitrypsin is a serine protease inhibitor that demonstrates an array of immunomodulatory functions. Individuals with the genetic condition of alpha-1 antitrypsin deficiency (AATD) are at increased risk of early onset emphysematous lung disease. This lung disease is partly driven by neutrophil mediated lung destruction in an environment of low AAT. As peripheral neutrophil hyper-responsiveness in AATD leads to excessive degranulation and increased migration to the airways, we examined the expression of the membrane voltage-gated proton channel-1 (HVCN1), which is integrally linked to neutrophil function. The objectives of this study were to evaluate altered HVCN1 in AATD neutrophils, serine protease-dependent degradation of HVCN1, and to investigate the ability of serum AAT to control HVCN1 expression. Materials and Methods: Circulating neutrophils were purified from AATD patients (n = 20), AATD patients receiving AAT augmentation therapy (n = 3) and healthy controls (n = 20). HVCN1 neutrophil expression was assessed by flow cytometry and Western blot analysis. Neutrophil membrane bound elastase was measured by fluorescence resonance energy transfer. Results: In this study we demonstrated that HVCN1 protein is under-expressed in AATD neutrophils (p = 0.02), suggesting a link between reduced HVCN1 expression and AAT deficiency. We have demonstrated that HVCN1 undergoes significant proteolytic degradation in activated neutrophils (p < 0.0001), primarily due to neutrophil elastase activity (p = 0.0004). In addition, the treatment of AATD individuals with AAT augmentation therapy increased neutrophil plasma membrane HVCN1 expression (p = 0.01). Conclusions: Our results demonstrate reduced levels of HVCN1 in peripheral blood neutrophils that may influence the neutrophil-dominated immune response in the AATD airways and highlights the role of antiprotease treatment and specifically AAT augmentation therapy in protecting neutrophil membrane expression of HVCN1.
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29
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Zhao C, Hong L, Galpin JD, Riahi S, Lim VT, Webster PD, Tobias DJ, Ahern CA, Tombola F. HIFs: New arginine mimic inhibitors of the Hv1 channel with improved VSD-ligand interactions. J Gen Physiol 2021; 153:212451. [PMID: 34228044 PMCID: PMC8263924 DOI: 10.1085/jgp.202012832] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 06/14/2021] [Indexed: 12/14/2022] Open
Abstract
The human voltage-gated proton channel Hv1 is a drug target for cancer, ischemic stroke, and neuroinflammation. It resides on the plasma membrane and endocytic compartments of a variety of cell types, where it mediates outward proton movement and regulates the activity of NOX enzymes. Its voltage-sensing domain (VSD) contains a gated and proton-selective conduction pathway, which can be blocked by aromatic guanidine derivatives such as 2-guanidinobenzimidazole (2GBI). Mutation of Hv1 residue F150 to alanine (F150A) was previously found to increase 2GBI apparent binding affinity more than two orders of magnitude. Here, we explore the contribution of aromatic interactions between the inhibitor and the channel in the presence and absence of the F150A mutation, using a combination of electrophysiological recordings, classic mutagenesis, and site-specific incorporation of fluorinated phenylalanines via nonsense suppression methodology. Our data suggest that the increase in apparent binding affinity is due to a rearrangement of the binding site allowed by the smaller residue at position 150. We used this information to design new arginine mimics with improved affinity for the nonrearranged binding site of the wild-type channel. The new compounds, named “Hv1 Inhibitor Flexibles” (HIFs), consist of two “prongs,” an aminoimidazole ring, and an aromatic group connected by extended flexible linkers. Some HIF compounds display inhibitory properties that are superior to those of 2GBI, thus providing a promising scaffold for further development of high-affinity Hv1 inhibitors.
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Affiliation(s)
- Chang Zhao
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA.,Chao Family Comprehensive Cancer Center, University of California, Irvine, Irvine, CA
| | - Liang Hong
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Saleh Riahi
- Department of Chemistry, University of California, Irvine, Irvine, CA
| | - Victoria T Lim
- Department of Chemistry, University of California, Irvine, Irvine, CA
| | - Parker D Webster
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
| | - Douglas J Tobias
- Chao Family Comprehensive Cancer Center, University of California, Irvine, Irvine, CA.,Department of Chemistry, University of California, Irvine, Irvine, CA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA.,Chao Family Comprehensive Cancer Center, University of California, Irvine, Irvine, CA
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30
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Du H, Pang H, Gao Y, Zhou Y, Li SJ. Deficiency of voltage-gated proton channel Hv1 aggravates ovalbumin-induced allergic lung asthma in mice. Int Immunopharmacol 2021; 96:107640. [PMID: 33866247 DOI: 10.1016/j.intimp.2021.107640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/18/2021] [Accepted: 04/01/2021] [Indexed: 02/07/2023]
Abstract
Asthma is a chronic airway inflammation that caused by many factors. The voltage-gated proton channel Hv1 has been proposed to extrude excessive protons produced by NADPH oxidase (NOX) from cytosol to maintain its activity during respiratory bursts. Here, we showed that loss of Hv1 aggravates ovalbumin (OVA)-induced allergic lung asthma in mice. The numbers of total cells, eosinophils and neutrophils in bronchoalveolar lavage fluid (BALF) of Hv1-deficiency (KO) mice are obviously increased after OVA challenge compared with that of wild-type (WT) mice. Histopathological staining reveals that Hv1-deficiency aggravates OVA-induced inflammatory cell infiltration and goblet cell hyperplasia in lung tissues. The expression of IL-4, IL-5 and IL-13 are markedly increased in lung tissues of OVA-challenged KO mice compared with that of WT mice. Furthermore, the expression levels of NOX2, NOX4 and DUOX1 are dramatically increased, while the expression levels of SOD2 and catalase are significantly reduced in lung tissues of OVA-challenged KO mice compared with that of WT mice. The production of ROS in lung tissues of KO mice is significantly higher than that of WT mice after OVA challenge. Our data suggest that Hv1-deficiency might aggravate the development of allergic asthma through increasing ROS production.
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Affiliation(s)
- Hongyan Du
- Department of Biophysics, School of Physical Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, China
| | - Huimin Pang
- Department of Biophysics, School of Physical Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, China
| | - Yingtang Gao
- Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Institute of Hepatobiliary Disease, Tianjin Third Central Hospital affiliated to Nankai University, 83 Jintang Road, Hedong District, Tianjin 300170, China
| | - Yongfa Zhou
- Department of Biophysics, School of Physical Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, China
| | - Shu Jie Li
- Department of Biophysics, School of Physical Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071, China; Qilu Institute of Technology, Shandong 250200, P. R. China.
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31
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Peng J, Yi MH, Jeong H, McEwan PP, Zheng J, Wu G, Ganatra S, Ren Y, Richardson JR, Oh SB, Wu LJ. The voltage-gated proton channel Hv1 promotes microglia-astrocyte communication and neuropathic pain after peripheral nerve injury. Mol Brain 2021; 14:99. [PMID: 34183051 PMCID: PMC8240390 DOI: 10.1186/s13041-021-00812-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/18/2021] [Indexed: 12/30/2022] Open
Abstract
Activation of spinal cord microglia contributes to the development of peripheral nerve injury-induced neuropathic pain. However, the molecular mechanisms underlying microglial function in neuropathic pain are not fully understood. We identified that the voltage-gated proton channel Hv1, which is functionally expressed in spinal microglia, was significantly increased after spinal nerve transection (SNT). Hv1 mediated voltage-gated proton currents in spinal microglia and mice lacking Hv1 (Hv1 KO) display attenuated pain hypersensitivities after SNT compared with wildtype (WT) mice. In addition, microglial production of reactive oxygen species (ROS) and subsequent astrocyte activation in the spinal cord was reduced in Hv1 KO mice after SNT. Cytokine screening and immunostaining further revealed that IFN-γ expression was compromised in spinal astrocytes in Hv1 KO mice. These results demonstrate that Hv1 proton channel contributes to microglial ROS production, astrocyte activation, IFN-γ upregulation, and subsequent pain hypersensitivities after SNT. This study suggests Hv1-dependent microglia-astrocyte communication in pain hypersensitivities and identifies Hv1 as a novel therapeutic target for alleviating neuropathic pain.
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Affiliation(s)
- Jiyun Peng
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA.
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA.
- Institute of Life Science, Nanchang University, Nanchang, 330031, China.
| | - Min-Hee Yi
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Heejin Jeong
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea
| | | | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Gongxiong Wu
- One Harvard Street Institute of Health, Brookline, MA, 02446, USA
| | - Shashank Ganatra
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Yi Ren
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Jason R Richardson
- Departments of Environmental Health Sciences, Florida International University, Miami, FL, 33199, USA
| | - Seog Bae Oh
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea.
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA.
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA.
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
- Department of Immunology, Mayo Clinic, Rochester, MN, 55905, USA.
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32
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Zhao R, Dai H, Arias RJ, De Blas GA, Orta G, Pavarotti MA, Shen R, Perozo E, Mayorga LS, Darszon A, Goldstein SAN. Direct activation of the proton channel by albumin leads to human sperm capacitation and sustained release of inflammatory mediators by neutrophils. Nat Commun 2021; 12:3855. [PMID: 34158477 PMCID: PMC8219737 DOI: 10.1038/s41467-021-24145-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 06/02/2021] [Indexed: 02/05/2023] Open
Abstract
Human voltage-gated proton channels (hHv1) extrude protons from cells to compensate for charge and osmotic imbalances due metabolism, normalizing intracellular pH and regulating protein function. Human albumin (Alb), present at various levels throughout the body, regulates oncotic pressure and transports ligands. Here, we report Alb is required to activate hHv1 in sperm and neutrophils. Dose-response studies reveal the concentration of Alb in semen is too low to activate hHv1 in sperm whereas the higher level in uterine fluid yields proton efflux, allowing capacitation, the acrosomal reaction, and oocyte fertilization. Likewise, Alb activation of hHv1 in neutrophils is required to sustain production and release of reactive oxygen species during the immune respiratory burst. One Alb binds to both voltage sensor domains (VSDs) in hHv1, enhancing open probability and increasing proton current. A computational model of the Alb-hHv1 complex, validated by experiments, identifies two sites in Alb domain II that interact with the VSDs, suggesting an electrostatic gating modification mechanism favoring the active "up" sensor conformation. This report shows how sperm are triggered to fertilize, resolving how hHv1 opens at negative membrane potentials in sperm, and describes a role for Alb in physiology that will operate in the many tissues expressing hHv1.
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics and Physiology & Biophysics, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, CA, USA
| | - Hui Dai
- Departments of Pediatrics and Physiology & Biophysics, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, CA, USA
| | - Rodolfo J Arias
- Instituto de Histología y Embriología de Mendoza (IHEM/CONICET-UNCuyo), School of Medicine, National University of Cuyo, Mendoza, CP, Argentina
| | - Gerardo A De Blas
- Instituto de Histología y Embriología de Mendoza (IHEM/CONICET-UNCuyo), School of Medicine, National University of Cuyo, Mendoza, CP, Argentina
- Laboratorio de Telediagnóstico e Investigación Traslacional (LaTIT). Área de Farmacología. Departamento de Patología, School of Medicine, National University of Cuyo, Mendoza, CP, Argentina
| | - Gerardo Orta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos, México
| | - Martín A Pavarotti
- Instituto de Histología y Embriología de Mendoza (IHEM/CONICET-UNCuyo), School of Medicine, National University of Cuyo, Mendoza, CP, Argentina
| | - Rong Shen
- Department of Biochemistry and Molecular Biology, Gordon Center for Integrative Science, University of Chicago, Chicago, IL, USA
| | - Eduardo Perozo
- Department of Biochemistry and Molecular Biology, Gordon Center for Integrative Science, University of Chicago, Chicago, IL, USA
| | - Luis S Mayorga
- Instituto de Histología y Embriología de Mendoza (IHEM/CONICET-UNCuyo), School of Medicine, National University of Cuyo, Mendoza, CP, Argentina
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos, México
| | - Steve A N Goldstein
- Departments of Pediatrics and Physiology & Biophysics, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, CA, USA.
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He J, Ritzel RM, Wu J. Functions and Mechanisms of the Voltage-Gated Proton Channel Hv1 in Brain and Spinal Cord Injury. Front Cell Neurosci 2021; 15:662971. [PMID: 33897377 PMCID: PMC8063047 DOI: 10.3389/fncel.2021.662971] [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: 02/02/2021] [Accepted: 03/18/2021] [Indexed: 12/25/2022] Open
Abstract
The voltage-gated proton channel Hv1 is a newly discovered ion channel that is highly conserved among species. It is known that Hv1 is not only expressed in peripheral immune cells but also one of the major ion channels expressed in tissue-resident microglia of the central nervous systems (CNS). One key role for Hv1 is its interaction with NADPH oxidase 2 (NOX2) to regulate reactive oxygen species (ROS) and cytosolic pH. Emerging data suggest that excessive ROS production increases and requires proton currents through Hv1 in the injured CNS, and manipulations that ablate Hv1 expression or induce loss of function may provide neuroprotection in CNS injury models including stroke, traumatic brain injury, and spinal cord injury. Recent data demonstrating microglial Hv1-mediated signaling in the pathophysiology of the CNS injury further supports the idea that Hv1 channel may function as a key mechanism in posttraumatic neuroinflammation and neurodegeneration. In this review, we summarize the main findings of Hv1, including its expression pattern, cellular mechanism, role in aging, and animal models of CNS injury and disease pathology. We also discuss the potential of Hv1 as a therapeutic target for CNS injury.
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Affiliation(s)
- Junyun He
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, United States
| | - Rodney M Ritzel
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, United States
| | - Junfang Wu
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD, United States.,University of Maryland Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD, United States
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Okochi Y, Okamura Y. Regulation of Neutrophil Functions by Hv1/VSOP Voltage-Gated Proton Channels. Int J Mol Sci 2021; 22:ijms22052620. [PMID: 33807711 PMCID: PMC7961965 DOI: 10.3390/ijms22052620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/25/2021] [Accepted: 03/01/2021] [Indexed: 12/15/2022] Open
Abstract
The voltage-gated proton channel, Hv1, also termed VSOP, was discovered in 2006. It has long been suggested that proton transport through voltage-gated proton channels regulate reactive oxygen species (ROS) production in phagocytes by counteracting the charge imbalance caused by the activation of NADPH oxidase. Discovery of Hv1/VSOP not only confirmed this process in phagocytes, but also led to the elucidation of novel functions in phagocytes. The compensation of charge by Hv1/VSOP sustains ROS production and is also crucial for promoting Ca2+ influx at the plasma membrane. In addition, proton extrusion into neutrophil phagosomes by Hv1/VSOP is necessary to maintain neutral phagosomal pH for the effective killing of bacteria. Contrary to the function of Hv1/VSOP as a positive regulator for ROS generation, it has been revealed that Hv1/VSOP also acts to inhibit ROS production in neutrophils. Hv1/VSOP inhibits hypochlorous acid production by regulating degranulation, leading to reduced inflammation upon fungal infection, and suppresses the activation of extracellular signal-regulated kinase (ERK) signaling by inhibiting ROS production. Thus, Hv1/VSOP is a two-way player regulating ROS production. Here, we review the functions of Hv1/VSOP in neutrophils and discuss future perspectives.
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Affiliation(s)
- Yoshifumi Okochi
- Integrative Physiology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita 5650871, Osaka, Japan;
- Correspondence:
| | - Yasushi Okamura
- Integrative Physiology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita 5650871, Osaka, Japan;
- Graduate School of Frontier Bioscience, Osaka University, 2-2 Yamada-oka, Suita 5650871, Osaka, Japan
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35
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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: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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36
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Messerer DAC, Schmidt H, Frick M, Huber-Lang M. Ion and Water Transport in Neutrophil Granulocytes and Its Impairment during Sepsis. Int J Mol Sci 2021; 22:1699. [PMID: 33567720 PMCID: PMC7914618 DOI: 10.3390/ijms22041699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
Neutrophil granulocytes are the vanguard of innate immunity in response to numerous pathogens. Their activity drives the clearance of microbe- and damage-associated molecular patterns, thereby contributing substantially to the resolution of inflammation. However, excessive stimulation during sepsis leads to cellular unresponsiveness, immunological dysfunction, bacterial expansion, and subsequent multiple organ dysfunction. During the short lifespan of neutrophils, they can become significantly activated by complement factors, cytokines, and other inflammatory mediators. Following stimulation, the cells respond with a defined (electro-)physiological pattern, including depolarization, calcium influx, and alkalization as well as with increased metabolic activity and polarization of the actin cytoskeleton. Activity of ion transport proteins and aquaporins is critical for multiple cellular functions of innate immune cells, including chemotaxis, generation of reactive oxygen species, and phagocytosis of both pathogens and tissue debris. In this review, we first describe the ion transport proteins and aquaporins involved in the neutrophil ion-water fluxes in response to chemoattractants. We then relate ion and water flux to cellular functions with a focus on danger sensing, chemotaxis, phagocytosis, and oxidative burst and approach the role of altered ion transport protein expression and activity in impaired cellular functions and cell death during systemic inflammation as in sepsis.
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Affiliation(s)
- David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, 89081 Ulm, Germany;
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, 89081 Ulm, Germany
| | - Hanna Schmidt
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany; (H.S.); (M.F.)
- Department of Pediatrics and Adolescent Medicine, University Hospital of Ulm, 89081 Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany; (H.S.); (M.F.)
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, 89081 Ulm, Germany;
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Hofschröer V, Najder K, Rugi M, Bouazzi R, Cozzolino M, Arcangeli A, Panyi G, Schwab A. Ion Channels Orchestrate Pancreatic Ductal Adenocarcinoma Progression and Therapy. Front Pharmacol 2021; 11:586599. [PMID: 33841132 PMCID: PMC8025202 DOI: 10.3389/fphar.2020.586599] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/30/2020] [Indexed: 02/06/2023] Open
Abstract
Pancreatic ductal adenocarcinoma is a devastating disease with a dismal prognosis. Therapeutic interventions are largely ineffective. A better understanding of the pathophysiology is required. Ion channels contribute substantially to the "hallmarks of cancer." Their expression is dysregulated in cancer, and they are "misused" to drive cancer progression, but the underlying mechanisms are unclear. Ion channels are located in the cell membrane at the interface between the intracellular and extracellular space. They sense and modify the tumor microenvironment which in itself is a driver of PDAC aggressiveness. Ion channels detect, for example, locally altered proton and electrolyte concentrations or mechanical stimuli and transduce signals triggered by these microenvironmental cues through association with intracellular signaling cascades. While these concepts have been firmly established for other cancers, evidence has emerged only recently that ion channels are drivers of PDAC aggressiveness. Particularly, they appear to contribute to two of the characteristic PDAC features: the massive fibrosis of the tumor stroma (desmoplasia) and the efficient immune evasion. Our critical review of the literature clearly shows that there is still a remarkable lack of knowledge with respect to the contribution of ion channels to these two typical PDAC properties. Yet, we can draw parallels from ion channel research in other fibrotic and inflammatory diseases. Evidence is accumulating that pancreatic stellate cells express the same "profibrotic" ion channels. Similarly, it is at least in part known which major ion channels are expressed in those innate and adaptive immune cells that populate the PDAC microenvironment. We explore potential therapeutic avenues derived thereof. Since drugs targeting PDAC-relevant ion channels are already in clinical use, we propose to repurpose those in PDAC. The quest for ion channel targets is both motivated and complicated by the fact that some of the relevant channels, for example, KCa3.1, are functionally expressed in the cancer, stroma, and immune cells. Only in vivo studies will reveal which arm of the balance we should put our weights on when developing channel-targeting PDAC therapies. The time is up to explore the efficacy of ion channel targeting in (transgenic) murine PDAC models before launching clinical trials with repurposed drugs.
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Affiliation(s)
| | - Karolina Najder
- Institute of Physiology II, University of Münster, Münster, Germany
| | - Micol Rugi
- Institute of Physiology II, University of Münster, Münster, Germany
| | - Rayhana Bouazzi
- Department of Experimental and Clinical Medicine, Section of Internal Medicine, University of Florence, Florence, Italy
| | - Marco Cozzolino
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, Section of Internal Medicine, University of Florence, Florence, Italy
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Albrecht Schwab
- Institute of Physiology II, University of Münster, Münster, Germany
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38
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Voltage and pH difference across the membrane control the S4 voltage-sensor motion of the Hv1 proton channel. Sci Rep 2020; 10:21293. [PMID: 33277511 PMCID: PMC7718894 DOI: 10.1038/s41598-020-77986-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/28/2020] [Indexed: 12/26/2022] Open
Abstract
The voltage-gated proton channel Hv1 is expressed in a variety of cells, including macrophages, sperm, and lung epithelial cells. Hv1 is gated by both the membrane potential and the difference between the intra- and extracellular pH (ΔpH). The coupling of voltage- and ∆pH-sensing is such that Hv1 opens only when the electrochemical proton gradient is outwardly directed. However, the molecular mechanism of this coupling is not known. Here, we investigate the coupling between voltage- and ΔpH-sensing of Ciona intestinalis proton channel (ciHv1) using patch-clamp fluorometry (PCF) and proton uncaging. We show that changes in ΔpH can induce conformational changes of the S4 voltage sensor. Our results are consistent with the idea that S4 can detect both voltage and ΔpH.
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39
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Thermodynamics and Mechanism of the Membrane Permeation of Hv1 Channel Blockers. J Membr Biol 2020; 254:5-16. [PMID: 33196887 DOI: 10.1007/s00232-020-00149-8] [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: 09/01/2020] [Accepted: 10/14/2020] [Indexed: 02/08/2023]
Abstract
The voltage-gated proton channel Hv1 mediates efflux of protons from the cell. Hv1 integrally contributes to various physiological processes including pH homeostasis and the respiratory burst of phagocytes. Inhibition of Hv1 may provide therapeutic avenues for the treatment of inflammatory diseases, breast cancer, and ischemic brain damage. In this work, we investigate two prototypical Hv1 inhibitors, 2-guanidinobenzimidazole (2GBI), and 5-chloro-2-guanidinobenzimidazole (GBIC), from an experimentally screened class of guanidine derivatives. Both compounds block proton conduction by binding the same site located on the intracellular side of the channel. However, when added to the extracellular medium, the compounds strongly differ in their ability to inhibit proton conduction, suggesting substantial differences in membrane permeability. Here, we compute the potential of mean force for each compound to permeate through the membrane using atomistic molecular dynamics simulations with the adaptive biasing force method. Our results rationalize the putative distinction between these two blockers with respect to their abilities to permeate the cellular membrane.
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40
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Kawai T, Kayama K, Tatsumi S, Akter S, Miyawaki N, Okochi Y, Abe M, Sakimura K, Yamamoto H, Kihara S, Okamura Y. Regulation of hepatic oxidative stress by voltage-gated proton channels (Hv1/VSOP) in Kupffer cells and its potential relationship with glucose metabolism. FASEB J 2020; 34:15805-15821. [PMID: 33040408 DOI: 10.1096/fj.202001056rrr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 01/20/2023]
Abstract
Voltage-gated proton channels (Hv1/VSOP), encoded by Hvcn1, are important regulator of reactive oxygen species (ROS) production in many types of immune cells. While in vitro studies indicate that Hv1/VSOP regulates ROS production by maintaining pH homeostasis, there are few studies investigating the functional importance of Hv1/VSOP in vivo. In the present study, we first show that Hv1/VSOP is functionally expressed in liver resident macrophage, Kupffer cells, regulating the hepatic oxidative stress in vivo. Our immunocytochemistry and electrophysiology data showed that Hvcn1 is specifically expressed in Kupffer cells, but not in hepatocytes. Furthermore, Hvcn1-deficiency drastically altered the hepatic oxidative stress. The Hvcn1-deficient mice showed high blood glucose and serum insulin but normal insulin sensitivity, indicating that these phenotypes were not linked to insulin resistance. Transcriptome analysis indicated that the gene expression of glycogen phosphorylase (Pygl) and Glucose-6-phosphatase, catalytic subunit (G6pc) were upregulated in Hvcn1-deficient liver tissues, and quantitative PCR confirmed the result for Pygl. Furthermore, we observed higher amount of glucose-6-phosphate, a key sugar intermediate for glucose in Hvcn1-deficient liver than WT, suggesting that glucose production in liver is accelerated in Hvcn1-deficient mice. The present study sheds light on the functional importance of Kupffer cells in hepatic oxidative stress and its potential relationship with glucose metabolism.
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Affiliation(s)
- Takafumi Kawai
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan
| | - Kento Kayama
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan.,Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Shoki Tatsumi
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan.,Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Sharmin Akter
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan
| | - Nana Miyawaki
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan
| | - Yoshifumi Okochi
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hiroyasu Yamamoto
- Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Shinji Kihara
- Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yasushi Okamura
- Integrative Physiology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Suita, Japan
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41
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Smith RY, Morgan D, Sharma L, Cherny VV, Tidswell N, Molo MW, DeCoursey TE. Voltage-gated proton channels exist in the plasma membrane of human oocytes. Hum Reprod 2020; 34:1974-1983. [PMID: 31633762 DOI: 10.1093/humrep/dez178] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/10/2019] [Indexed: 12/25/2022] Open
Abstract
STUDY QUESTION Do human oocytes express voltage-gated proton channels? SUMMARY ANSWER Human oocytes exhibit voltage-gated proton currents. WHAT IS KNOWN ALREADY Voltage-gated proton currents have been reported in human sperm, where they contribute to capacitation and motility. No such studies of human oocytes exist. STUDY DESIGN, SIZE, DURATION Voltage-clamp studies were undertaken using entire oocytes and vesicles derived from oocytes and in excised patches of membrane from oocytes. PARTICIPANTS/MATERIALS, SETTING, METHODS Frozen, thawed human metaphase II oocytes were obtained from material donated to the gamete repository at the Rush Center for Advanced Reproductive Care. Prior to patch clamping, oocytes were warmed and equilibrated. Formation of an electrically tight seal requires exposing bare oolemma. Sections of the zona pellucida (ZP) were removed using a laser, followed by repeated pipetting, to further separate the oocyte from the ZP. Patch-clamp studies were performed using the whole-cell configuration on oocytes or vesicles derived from oocytes, and using inside-out patches of membrane, under conditions optimized to detect voltage-gated proton currents. MAIN RESULTS AND THE ROLE OF CHANCE Proton currents are present at significant levels in human oocytes where they exhibit properties similar to those reported in other human cells, as well as those in heterologous expression systems transfected with the HVCN1 gene that codes for the voltage-gated proton channel. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Human oocytes are large cells, which limits our ability to control the intracellular solution. Subtle effects of cryopreservation by vitrification and subsequent warming on properties of HVCN1, the HVCN1 gene product, cannot be ruled out. WIDER IMPLICATIONS OF THE FINDINGS Possible functions for voltage-gated proton channels in human oocytes may now be contemplated. STUDY FUNDING/COMPETING INTEREST(S) NIH R35GM126902 (TED), Bears Care (DM). No competing interests. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- R Ya Smith
- Rush Center for Advanced Reproductive Care, Department of Obstetrics and Gynecology, Rush University Medical Center, Chicago, IL 60612, USA
| | - D Morgan
- Department of Physiology & Biophysics, Rush University, Chicago, IL 60612, USA
| | - L Sharma
- Rush Center for Advanced Reproductive Care, Department of Obstetrics and Gynecology, Rush University Medical Center, Chicago, IL 60612, USA
| | - V V Cherny
- Department of Physiology & Biophysics, Rush University, Chicago, IL 60612, USA
| | - N Tidswell
- Rush Center for Advanced Reproductive Care, Department of Obstetrics and Gynecology, Rush University Medical Center, Chicago, IL 60612, USA
| | - M W Molo
- Rush Center for Advanced Reproductive Care, Department of Obstetrics and Gynecology, Rush University Medical Center, Chicago, IL 60612, USA
| | - T E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, IL 60612, USA
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42
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Najder K, Rugi M, Lebel M, Schröder J, Oster L, Schimmelpfennig S, Sargin S, Pethő Z, Bulk E, Schwab A. Role of the Intracellular Sodium Homeostasis in Chemotaxis of Activated Murine Neutrophils. Front Immunol 2020; 11:2124. [PMID: 33013896 PMCID: PMC7506047 DOI: 10.3389/fimmu.2020.02124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/05/2020] [Indexed: 12/17/2022] Open
Abstract
The importance of the intracellular Ca2+ concentration ([Ca2+]i) in neutrophil function has been intensely studied. However, the role of the intracellular Na+ concentration ([Na+]i) which is closely linked to the intracellular Ca2+ regulation has been largely overlooked. The [Na+]i is regulated by Na+ transport proteins such as the Na+/Ca2+-exchanger (NCX1), Na+/K+-ATPase, and Na+-permeable, transient receptor potential melastatin 2 (TRPM2) channel. Stimulating with either N-formylmethionine-leucyl-phenylalanine (fMLF) or complement protein C5a causes distinct changes of the [Na+]i. fMLF induces a sustained increase of [Na+]i, surprisingly, reaching higher values in TRPM2-/- neutrophils. This outcome is unexpected and remains unexplained. In both genotypes, C5a elicits only a transient rise of the [Na+]i. The difference in [Na+]i measured at t = 10 min after stimulation is inversely related to neutrophil chemotaxis. Neutrophil chemotaxis is more efficient in C5a than in an fMLF gradient. Moreover, lowering the extracellular Na+ concentration from 140 to 72 mM improves chemotaxis of WT but not of TRPM2-/- neutrophils. Increasing the [Na+]i by inhibiting the Na+/K+-ATPase results in disrupted chemotaxis. This is most likely due to the impact of the altered Na+ homeostasis and presumably NCX1 function whose expression was shown by means of qPCR and which critically relies on proper extra- to intracellular Na+ concentration gradients. Increasing the [Na+]i by a few mmol/l may suffice to switch its transport mode from forward (Ca2+-efflux) to reverse (Ca2+-influx) mode. The role of NCX1 in neutrophil chemotaxis is corroborated by its blocker, which also causes a complete inhibition of chemotaxis.
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Affiliation(s)
- Karolina Najder
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Micol Rugi
- Institute of Physiology II, University Hospital Münster, Münster, Germany
- University of Florence, Florence, Italy
| | - Mégane Lebel
- University of Sherbrooke, Sherbrooke, QC, Canada
| | - Julia Schröder
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Leonie Oster
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | | | - Sarah Sargin
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Zoltán Pethő
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Etmar Bulk
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, University Hospital Münster, Münster, Germany
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Madreiter-Sokolowski CT, Thomas C, Ristow M. Interrelation between ROS and Ca 2+ in aging and age-related diseases. Redox Biol 2020; 36:101678. [PMID: 32810740 PMCID: PMC7451758 DOI: 10.1016/j.redox.2020.101678] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/26/2020] [Accepted: 08/05/2020] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca2+) and reactive oxygen species (ROS) are versatile signaling molecules coordinating physiological and pathophysiological processes. While channels and pumps shuttle Ca2+ ions between extracellular space, cytosol and cellular compartments, short-lived and highly reactive ROS are constantly generated by various production sites within the cell. Ca2+ controls membrane potential, modulates mitochondrial adenosine triphosphate (ATP) production and affects proteins like calcineurin (CaN) or calmodulin (CaM), which, in turn, have a wide area of action. Overwhelming Ca2+ levels within mitochondria efficiently induce and trigger cell death. In contrast, ROS comprise a diverse group of relatively unstable molecules with an odd number of electrons that abstract electrons from other molecules to gain stability. Depending on the type and produced amount, ROS act either as signaling molecules by affecting target proteins or as harmful oxidative stressors by damaging cellular components. Due to their wide range of actions, it is little wonder that Ca2+ and ROS signaling pathways overlap and impact one another. Growing evidence suggests a crucial implication of this mutual interplay on the development and enhancement of age-related disorders, including cardiovascular and neurodegenerative diseases as well as cancer.
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Affiliation(s)
- Corina T Madreiter-Sokolowski
- Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland; Holder of an Erwin Schroedinger Abroad Fellowship, Austrian Science Fund (FWF), Austria.
| | - Carolin Thomas
- Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Michael Ristow
- Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
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Lim VT, Geragotelis AD, Lim NM, Freites JA, Tombola F, Mobley DL, Tobias DJ. Insights on small molecule binding to the Hv1 proton channel from free energy calculations with molecular dynamics simulations. Sci Rep 2020; 10:13587. [PMID: 32788614 PMCID: PMC7423955 DOI: 10.1038/s41598-020-70369-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/23/2020] [Indexed: 02/07/2023] Open
Abstract
Hv1 is a voltage-gated proton channel whose main function is to facilitate extrusion of protons from the cell. The development of effective channel blockers for Hv1 can lead to new therapeutics for the treatment of maladies related to Hv1 dysfunction. Although the mechanism of proton permeation in Hv1 remains to be elucidated, a series of small molecules have been discovered to inhibit Hv1. Here, we computed relative binding free energies of a prototypical Hv1 blocker on a model of human Hv1 in an open state. We used alchemical free energy perturbation techniques based on atomistic molecular dynamics simulations. The results support our proposed open state model and shed light on the preferred tautomeric state of the channel blocker. This work lays the groundwork for future studies on adapting the blocker molecule for more effective inhibition of Hv1.
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Affiliation(s)
- Victoria T Lim
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | | | - Nathan M Lim
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, 92697, USA
| | - J Alfredo Freites
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California, Irvine, CA, 92697, USA
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA
| | - David L Mobley
- Department of Chemistry, University of California, Irvine, CA, 92697, USA.
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, 92697, USA.
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, CA, 92697, USA.
- Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA.
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Voltage-dependent structural models of the human Hv1 proton channel from long-timescale molecular dynamics simulations. Proc Natl Acad Sci U S A 2020; 117:13490-13498. [PMID: 32461356 DOI: 10.1073/pnas.1920943117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The voltage-gated Hv1 proton channel is a ubiquitous membrane protein that has roles in a variety of cellular processes, including proton extrusion, pH regulation, production of reactive oxygen species, proliferation of cancer cells, and increased brain damage during ischemic stroke. A crystal structure of an Hv1 construct in a putative closed state has been reported, and structural models for the channel open state have been proposed, but a complete characterization of the Hv1 conformational dynamics under an applied membrane potential has been elusive. We report structural models of the Hv1 voltage-sensing domain (VSD), both in a hyperpolarized state and a depolarized state resulting from voltage-dependent conformational changes during a 10-μs-timescale atomistic molecular dynamics simulation in an explicit membrane environment. In response to a depolarizing membrane potential, the S4 helix undergoes an outward displacement, leading to changes in the VSD internal salt-bridge network, resulting in a reshaping of the permeation pathway and a significant increase in hydrogen bond connectivity throughout the channel. The total gating charge displacement associated with this transition is consistent with experimental estimates. Molecular docking calculations confirm the proposed mechanism for the inhibitory action of 2-guanidinobenzimidazole (2GBI) derived from electrophysiological measurements and mutagenesis. The depolarized structural model is also consistent with the formation of a metal bridge between residues located in the core of the VSD. Taken together, our results suggest that these structural models are representative of the closed and open states of the Hv1 channel.
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Bare DJ, Cherny VV, DeCoursey TE, Abukhdeir AM, Morgan D. Expression and function of voltage gated proton channels (Hv1) in MDA-MB-231 cells. PLoS One 2020; 15:e0227522. [PMID: 32374759 PMCID: PMC7202653 DOI: 10.1371/journal.pone.0227522] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/09/2020] [Indexed: 02/07/2023] Open
Abstract
Expression of the voltage gated proton channel (Hv1) as identified by immunocytochemistry has been reported previously in breast cancer tissue. Increased expression of HV1 was correlated with poor prognosis and decreased overall and disease-free survival but the mechanism of its involvement in the disease is unknown. Here we present electrophysiological recordings of HV1 channel activity, confirming its presence and function in the plasma membrane of a breast cancer cell line, MDA-MB-231. With western blotting we identify significant levels of HV1 expression in 3 out of 8 “triple negative” breast cancer cell lines (estrogen, progesterone, and HER2 receptor expression negative). We examine the function of HV1 in breast cancer using MDA-MB-231 cells as a model by suppressing the expression of HV1 using shRNA (knock-down; KD) and by eliminating HV1 using CRISPR/Cas9 gene editing (knock-out; KO). Surprisingly, these two approaches produced incongruous effects. Knock-down of HV1 using shRNA resulted in slower cell migration in a scratch assay and a significant reduction in H2O2 release. In contrast, HV1 Knock-out cells did not show reduced migration or H2O2 release. HV1 KO but not KD cells showed an increased glycolytic rate accompanied by an increase in p-AKT (phospho-AKT, Ser473) activity. The expression of CD171/LCAM-1, an adhesion molecule and prognostic indicator for breast cancer, was reduced in HV1 KO cells. When we compared MDA-MB-231 xenograft growth rates in immunocompromised mice, tumors from HV1 KO cells grew less than WT in mass, with lower staining for the Ki-67 marker for cell proliferation rate. Therefore, deletion of HV1 expression in MDA-MB-231 cells limits tumor growth rate. The limited growth thus appears to be independent of oxidant production by NADPH oxidase molecules and to be mediated by cell adhesion molecules. Although HV1 KO and KD affect certain cellular mechanisms differently, both implicate HV1-mediated pathways for control of tumor growth in the MDA-MB-231 cell line.
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Affiliation(s)
- Dan J Bare
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Vladimir V Cherny
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Thomas E DeCoursey
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Abde M Abukhdeir
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL, United States of America
| | - Deri Morgan
- Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, MO, United States of America
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The voltage-gated proton channel hHv1 is functionally expressed in human chorion-derived mesenchymal stem cells. Sci Rep 2020; 10:7100. [PMID: 32346069 PMCID: PMC7188850 DOI: 10.1038/s41598-020-63517-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/01/2020] [Indexed: 01/08/2023] Open
Abstract
The voltage-gated proton channel Hv1 is widely expressed, among others, in immune and cancer cells, it provides an efficient cytosolic H+extrusion mechanism and regulates vital functions such as oxidative burst, migration and proliferation. Here we demonstrate the presence of human Hv1 (hHv1) in the placenta/chorion-derived mesenchymal stem cells (cMSCs) using RT-PCR. The voltage- and pH-dependent gating of the current is similar to that of hHv1 expressed in cell lines and that the current is blocked by 5-chloro-2-guanidinobenzimidazole (ClGBI) and activated by arachidonic acid (AA). Inhibition of hHv1 by ClGBI significantly decreases mineral matrix production of cMSCs induced by conditions mimicking physiological or pathological (inorganic phosphate, Pi) induction of osteogenesis. Wound healing assay and single cell motility analysis show that ClGBI significantly inhibits the migration of cMSCs. Thus, seminal functions of cMSCs are modulated by hHv1 which makes this channel as an attractive target for controlling advantages/disadvantages of MSCs therapy.
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Okochi Y, Umemoto E, Okamura Y. Hv1/VSOP regulates neutrophil directional migration and ERK activity by tuning ROS production. J Leukoc Biol 2020; 107:819-831. [DOI: 10.1002/jlb.2a0320-110rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Yoshifumi Okochi
- Integrative Physiology, Graduate School of Medicine Osaka University Osaka Japan
| | - Eiji Umemoto
- Laboratory of Microbiology and Immunology School of Pharmaceutical Sciences University of Shizuoka Japan
| | - Yasushi Okamura
- Integrative Physiology, Graduate School of Medicine Osaka University Osaka Japan
- Graduate School of Frontier Biosciences Osaka University Osaka Japan
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Chaves G, Bungert-Plümke S, Franzen A, Mahorivska I, Musset B. Zinc modulation of proton currents in a new voltage-gated proton channel suggests a mechanism of inhibition. FEBS J 2020; 287:4996-5018. [PMID: 32160407 PMCID: PMC7754295 DOI: 10.1111/febs.15291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/10/2020] [Accepted: 03/10/2020] [Indexed: 02/03/2023]
Abstract
The HV1 voltage‐gated proton (HV1) channel is a key component of the cellular proton extrusion machinery and is pivotal for charge compensation during the respiratory burst of phagocytes. The best‐described physiological inhibitor of HV1 is Zn2+. Externally applied ZnCl2 drastically reduces proton currents reportedly recorded in Homo sapiens, Rattus norvegicus, Mus musculus, Oryctolagus cuniculus, Rana esculenta, Helix aspersa, Ciona intestinalis, Coccolithus pelagicus, Emiliania huxleyi, Danio rerio, Helisoma trivolvis, and Lingulodinium polyedrum, but with considerable species variability. Here, we report the effects of Zn2+ and Cd2+ on HV1 from Nicoletia phytophila, NpHV1. We introduced mutations at potential Zn2+ coordination sites and measured Zn2+ inhibition in different extracellular pH, with Zn2+ concentrations up to 1000 μm. Zn2+ inhibition in NpHV1 was quantified by the slowing of the activation time constant and a positive shift of the conductance–voltage curve. Replacing aspartate in the S3‐S4 loop with histidine (D145H) enhanced both the slowing of activation kinetics and the shift in the voltage–conductance curve, such that Zn2+ inhibition closely resembled that of the human channel. Histidine is much more effective than aspartate in coordinating Zn2+ in the S3‐S4 linker. A simple Hodgkin Huxley model of NpHV1 suggests a decrease in the opening rate if it is inhibited by zinc or cadmium. Limiting slope measurements and high‐resolution clear native gel electrophoresis (hrCNE) confirmed that NpHV1 functions as a dimer. The data support the hypothesis that zinc is coordinated in between the dimer instead of the monomer. Zinc coordination sites may be potential targets for drug development.
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Affiliation(s)
- Gustavo Chaves
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
| | - Stefanie Bungert-Plümke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich, Jülich, Germany
| | - Arne Franzen
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4) Forschungszentrum Jülich, Jülich, Germany
| | - Iryna Mahorivska
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
| | - Boris Musset
- Institut für Physiologie und Pathophysiologie, Paracelsus Universität Salzburg Standort Nürnberg, Nuremberg, Germany
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50
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Tang D, Yang Y, Xiao Z, Xu J, Yang Q, Dai H, Liang S, Tang C, Dong H, Liu Z. Scorpion toxin inhibits the voltage-gated proton channel using a Zn 2+ -like long-range conformational coupling mechanism. Br J Pharmacol 2020; 177:2351-2364. [PMID: 31975366 DOI: 10.1111/bph.14984] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/27/2019] [Accepted: 12/30/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Blocking the voltage-gated proton channel HV 1 is a promising strategy for the treatment of diseases like ischaemia stroke and cancer. However, few HV 1 channel antagonists have been reported. Here, we have identified a novel HV 1 channel antagonist from scorpion venom and have elucidated its action mechanism. EXPERIMENTAL APPROACH HV 1 and NaV channels were heterologously expressed in mammalian cell lines and their currents recorded using whole-cell patch clamp. Site-directed mutagenesis was used to generate mutants. Toxins were recombinantly produced in Escherichia coli. AGAP/W38F-HV 1 interaction was modelled by molecular dynamics simulations. KEY RESULTS The scorpion toxin AGAP (anti-tumour analgesic peptide) potently inhibited HV 1 currents. One AGAP mutant has reduced NaV channel activity but intact HV 1 activity (AGAP/W38F). AGAP/W38F inhibited HV 1 channel activation by trapping its S4 voltage sensor in a deactivated state and inhibited HV 1 currents with less pH dependence than Zn2+ . Mutation analysis showed that the binding pockets of AGAP/W38F and Zn2+ in HV 1 channel partly overlapped (common sites are His140 and His193). The E153A mutation at the intracellular Coulombic network (ICN) in HV 1 channel markedly reduced AGAP/W38F inhibition, as observed for Zn2+ . Experimental data and MD simulations suggested that AGAP/W38F inhibited HV 1 channel using a Zn2+ -like long-range conformational coupling mechanism. CONCLUSION AND IMPLICATIONS Our results suggest that the Zn2+ binding pocket in HV 1 channel might be a hotspot for modulators and valuable for designing HV 1 channel ligands. Moreover, AGAP/W38F is a useful molecular probe to study HV 1 channel and a lead compound for drug development.
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Affiliation(s)
- Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yuqin Yang
- Kuang Yaming Honors School, Nanjing University, Nanjing, China.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Zhen Xiao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Jiahui Xu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Qiuchu Yang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Han Dai
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Hao Dong
- Kuang Yaming Honors School, Nanjing University, Nanjing, China.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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