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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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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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3
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Sánchez-Cárdenas C, Romarowski A, Orta G, De la Vega-Beltrán JL, Martín-Hidalgo D, Hernández-Cruz A, Visconti PE, Darszon A. Starvation induces an increase in intracellular calcium and potentiates the progesterone-induced mouse sperm acrosome reaction. FASEB J 2021; 35:e21528. [PMID: 33742713 DOI: 10.1096/fj.202100122r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 12/26/2022]
Abstract
We have recently reported two different methodologies that improve sperm functionality. The first method involved transient exposure to the Ca2+ ionophore A23187 , and the second required sperm incubation in the absence of energy nutrients (starvation). Both methods were associated with an initial loss of motility followed by a rescue step involving ionophore removal or addition of energy metabolites, respectively. In this work, we show that starvation is accompanied by an increase in intracellular Ca2+ ([Ca2+ ]i ). Additionally, the starved cells acquire a significantly enhanced capacity to undergo a progesterone-induced acrosome reaction. Electrophysiological measurements show that CatSper channel remains active in starvation conditions. However, the increase in [Ca2+ ]i was also observed in sperm from CatSper null mice. Upon starvation, addition of energy nutrients reversed the effects on [Ca2+ ]i and decreased the effect of progesterone on the acrosome reaction to control levels. These data indicate that both methods have common molecular features.
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Affiliation(s)
- Claudia Sánchez-Cárdenas
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, México
| | - Ana Romarowski
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Gerardo Orta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, México
| | - José Luis De la Vega-Beltrán
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, México
| | - David Martín-Hidalgo
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA.,Research Group of Intracellular Signalling and Technology of Reproduction (Research Institute INBIO G+C), University of Extremadura, Cáceres, Spain
| | - Arturo Hernández-Cruz
- Departamento de Neurociencia Cognitiva and Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, UNAM, Ciudad Universitaria, México, México
| | - Pablo E Visconti
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, México
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4
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Huang M, Liang X, Zhang Z, Wang J, Fei Y, Ma J, Qu S, Mi L. Carbon Dots for Intracellular pH Sensing with Fluorescence Lifetime Imaging Microscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E604. [PMID: 32218205 PMCID: PMC7221822 DOI: 10.3390/nano10040604] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 03/11/2020] [Accepted: 03/24/2020] [Indexed: 12/11/2022]
Abstract
The monitoring of intracellular pH is of great importance for understanding intracellular trafficking and functions. It has various limitations for biosensing based on the fluorescence intensity or spectra study. In this research, pH-sensitive carbon dots (CDs) were employed for intracellular pH sensing with fluorescence lifetime imaging microscopy (FLIM) for the first time. FLIM is a highly sensitive method that is used to detect a microenvironment and it can overcome the limitations of biosensing methods based on fluorescence intensity. The different groups on the CDs surfaces changing with pH environments led to different fluorescence lifetime values. The CDs aqueous solution had a gradual change from 1.6 ns to 3.7 ns in the fluorescence lifetime with a pH range of 2.6-8.6. Similar fluorescence lifetime changes were found in pH buffer-treated living cells. The detection of lysosomes, cytoplasm, and nuclei in living cells was achieved by measuring the fluorescence lifetime of CDs. In particular, a phasor FLIM analysis was used to improve the pH imaging. Moreover, the effects of the coenzymes, amino acids, and proteins on the fluorescence lifetime of CDs were examined in order to mimic the complex microenvironment inside the cells.
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Affiliation(s)
- Maojia Huang
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
| | - Xinyue Liang
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
| | - Zixiao Zhang
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
| | - Jing Wang
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;
| | - Yiyan Fei
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
| | - Jiong Ma
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
- Institute of Biomedical Engineering and Technology, Academy for Engineer and Technology, Fudan University, Shanghai 200433, China
- The Multiscale Research Institute of Complex Systems (MRICS), School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Songnan Qu
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
| | - Lan Mi
- Department of Optical Science and Engineering, Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing, Green Photoelectron Platform, Fudan University, Shanghai 200433, China; (M.H.); (X.L.); (Z.Z.); (Y.F.)
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5
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Yu Y, Luo X, Li C, Ding F, Wang M, Xie M, Yu Z, Ransom BR, Wang W. Microglial Hv1 proton channels promote white matter injuries after chronic hypoperfusion in mice. J Neurochem 2019; 152:350-367. [PMID: 31769505 DOI: 10.1111/jnc.14925] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/16/2019] [Accepted: 11/19/2019] [Indexed: 12/30/2022]
Abstract
Microglia are critical in damage/repair processes during ischemic white matter injury (WMI). Voltage-gated proton channel (Hv1) is expressed in microglia and contributes to nicotinamide adenine dinucleotide phosphate oxidase complex-dependent production of reactive oxygen species (ROS). Recent findings have shown that Hv1 is involved in regulating luminal pH of M1-polarized microglial phagosomes and inhibits endocytosis in microglia. We previously reported that Hv1 facilitated production of ROS and pro-inflammatory cytokines in microglia and enhanced damage to oligodendrocyte progenitor cells from oxygen and glucose deprivation. To investigate the role of Hv1 in hypoperfusion-induced WMI, we employed mice that were genetically devoid of Hv1 (Hv1-/- ), as well as a model of subcortical vascular dementia via bilateral common carotid artery stenosis. Integrity of myelin was assessed using immunofluorescent staining and transmission electron microscopy, while cognitive impairment was assessed using an eight-arm radial maze test. Hv1 deficiency was found to attenuate bilateral common carotid artery stenosis-induced disruption of white matter integrity and impairment of working memory. Immunofluorescent staining and western blotting were used to assay changes in oligodendrocytes, OPCs, and microglial polarization. Compared with that in wild-type (WT) mice, Hv1-/- mice exhibited reduced ROS generation, decreased pro-inflammatory cytokines production, and an M2-dominant rather than M1-dominant microglial polarization. Furthermore, Hv1-/- mice exhibited enhanced OPC proliferation and differentiation into oligodendrocytes. Results of mouse-derived microglia-OPC co-cultures suggested that PI3K/Akt signaling was involved in Hv1-deficiency-induced M2-type microglial polarization and concomitant OPC differentiation. These results suggest that microglial Hv1 is a promising therapeutic target for reducing ischemic WMI and cognitive impairment.
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Affiliation(s)
- Ying Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunyu Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fengfei Ding
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiyuan Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bruce R Ransom
- Department of Neurology, University of Washington School of Medicine HMC, Seattle, WA, USA
| | - Wei Wang
- 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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Cooperative electrogenic proton transport pathways in the plasma membrane of the proton-secreting osteoclast. Pflugers Arch 2018; 470:851-866. [PMID: 29550927 DOI: 10.1007/s00424-018-2137-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 02/13/2018] [Accepted: 03/06/2018] [Indexed: 02/05/2023]
Abstract
A proton is a ubiquitous signaling ion. Many transmembrane H+ transport pathways either maintain pH homeostasis or generate acidic compartments. The osteoclast is a bone-resorbing cell, which degrades bone tissues by secreting protons and lysosomal enzymes into the resorption pit. The plasma membrane facing bone tissue (ruffled border), generated partly by fusion of lysosomes, may mimic H+ flux mechanisms regulating acidic vesicles. We identified three electrogenic H+-fluxes in osteoclast plasma membranes-a vacuolar H+-ATPase (V-ATPase), a voltage-gated proton channel (Hv channel) and an acid-inducible H+-leak-whose electrophysiological profiles and regulation mechanisms differed. V-ATPase and Hv channel, both may have intracellular reservoirs, but the recruitment/internalization is regulated independently. V-ATPase mediates active H+ efflux, acidifying the resorption pit, while acid-inducible H+ leak, activated at an extracellular pH < 5.5, diminishes pit acidification, possibly to protect bone from excess degradation. The two-way H+ flux mechanisms in opposite directions may have advantages in fine regulation of pit pH. Hv channel mediates passive H+ efflux. Although its working ranges are limited, the amount of H+ extrusion is 100 times larger than those of the V-ATPase and may support reactive oxygen species production during osteoclastogenesis. Extracellular Ca2+, H+ and inorganic phosphate, which accumulate in the resorption pit, will either stimulate or inhibit these H+ fluxes. Skeletal integration is disrupted by too much or too less of bone resorption. Diversities in plasma membrane H+ flux pathways, which may co-operate or compete, are essential to adjust osteoclast functions in variable conditions.
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7
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Navarro G, Martínez-Pinilla E, Sánchez-Melgar A, Ortiz R, Noé V, Martín M, Ciudad C, Franco R. A genomics approach identifies selective effects of trans-resveratrol in cerebral cortex neuron and glia gene expression. PLoS One 2017; 12:e0176067. [PMID: 28441400 PMCID: PMC5404873 DOI: 10.1371/journal.pone.0176067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/05/2017] [Indexed: 01/28/2023] Open
Abstract
The mode of action of trans-resveratrol, a promising lead compound for the development of neuroprotective drugs, is unknown. Data from a functional genomics study were retrieved with the aim to find differentially expressed genes that may be involved in the benefits provided by trans-resveratrol. Genes that showed a significantly different expression (p<0.05, cut-off of a two-fold change) in mice fed with a control diet or a control diet containing trans-resveratrol were different in cortex, heart and skeletal muscle. In neocortex, we identified 4 up-regulated (Strap, Pkp4, Rab2a, Cpne3) and 22 down-regulated (Actn1, Arf3, Atp6v01, Atp1a3, Atp1b2, Cacng7, Crtc1, Dbn1, Dnm1, Epn1, Gfap, Hap, Mark41, Rab5b, Nrxn2, Ogt, Palm, Ptprn2, Ptprs, Syn2, Timp2, Vamp2) genes upon trans-resveratrol consumption. Network analysis of gene products provided evidence of plakophilin 4 up-regulation as a triggering factor for down-regulation of events related to synaptic vesicle transport and neurotransmitter release via underexpression of dynamin1 and Vamp2 (synaptobrevin 2) as node-gene drivers. Analysis by RT-qPCR of some of the selected genes in a glioma cell line showed that dynamin 1 mRNA was down-regulated even in acute trans-resveratrol treatments. Taken all together, these results give insight on the glial-neuronal networks involved in the neuroprotective role of trans-resveratrol.
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Affiliation(s)
- Gemma Navarro
- CIBERNED. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Instituto de Salud Carlos III, Madrid, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias, Spain
- * E-mail:
| | - Alejandro Sánchez-Melgar
- Facultad de Ciencias y Tecnologías Químicas & Facultad de Medicina. Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Raquel Ortiz
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Véronique Noé
- Department of Biochemistry and Physiology, School of Pharmacy, University of Barcelona, Barcelona, Spain
- Institute of Nanotechnology of the University of Barcelona (IN2UB), Barcelona, Spain
| | - Mairena Martín
- Facultad de Ciencias y Tecnologías Químicas & Facultad de Medicina. Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro Regional de Investigaciones Biomédicas (CRIB), Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Carlos Ciudad
- Department of Biochemistry and Physiology, School of Pharmacy, University of Barcelona, Barcelona, Spain
- Institute of Nanotechnology of the University of Barcelona (IN2UB), Barcelona, Spain
| | - Rafael Franco
- CIBERNED. Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Instituto de Salud Carlos III, Madrid, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
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8
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Li G, Miura K, Kuno M. Extracellular phosphates enhance activities of voltage-gated proton channels and production of reactive oxygen species in murine osteoclast-like cells. Pflugers Arch 2016; 469:279-292. [PMID: 27999941 DOI: 10.1007/s00424-016-1931-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/11/2016] [Accepted: 12/13/2016] [Indexed: 10/20/2022]
Abstract
Osteoclasts are highly differentiated bone-resorbing cells and play a significant role in bone remodelling. In the resorption pit, inorganic phosphate (Pi) concentrations increase because of degradation of hydroxyapatite. We studied effects of extracellular Pi on voltage-gated H+ channels in osteoclast-like cells derived from a macrophage cell line (RAW264). Extracellular Pi (1.25-20 mM) increased the H+ channel currents dose dependently and reversibly. The Pi-induced increases were attenuated by removal of extracellular Na+ and by phosphonoformic acid, a blocker of Na+-dependent Pi transporters. Pi increased the maximal conductance, decreased activation time constant, increased deactivation time constant, and shifted the conductance-voltage relationship to more negative voltages. The most marked change was enhanced gating which was mainly caused by elevation of intracellular Pi levels. The Pi-induced enhanced gating was partially inhibited by protein kinase C (PKC) inhibitors, GF109203X and staurosporine, indicating that PKC-mediated phosphorylation was involved in part. The increase in the maximal conductance was mainly due to accompanying decrease in intracellular pH. These effects of Pi were not affected by intracellular Mg2+, bafilomycin A1 (V-ATPase inhibitor) and removal of intracellular ATP. Extracellular Pi also upregulated reactive oxygen species (ROS). Diphenyleneiodonium chloride, an inhibitor of NADPH oxidases, decreased ROS production and partially attenuated the enhanced gating. In the cells during later passages where osteoclastogenesis declined, H+ channel activities and ROS production were both modest. These results suggest that, in osteoclasts, ambient Pi is a common enhancer for H+ channels and ROS production and that potentiation of H+ channels may help ROS production.
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Affiliation(s)
- Guangshuai Li
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.,Department of Applied Pharmacology and Therapeutics, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, 545-8585, Japan
| | - Katsuyuki Miura
- Department of Applied Pharmacology and Therapeutics, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, 545-8585, Japan
| | - Miyuki Kuno
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
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9
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Marcoline FV, Ishida Y, Mindell JA, Nayak S, Grabe M. A mathematical model of osteoclast acidification during bone resorption. Bone 2016; 93:167-180. [PMID: 27650914 PMCID: PMC5077641 DOI: 10.1016/j.bone.2016.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 08/16/2016] [Accepted: 09/09/2016] [Indexed: 12/01/2022]
Abstract
Bone resorption by osteoclasts occurs through the creation of a sealed extracellular compartment (ECC), or pit, adjacent to the bone that is subsequently acidified through a complex biological process. The low pH of the pit dissolves the bone mineral and activates acid proteases that further break down the bone matrix. There are many ion channels, transporters, and soluble proteins involved in osteoclast mediated resorption, and in the past few years, there has been an increased understanding of the identity and properties of some key proteins such as the ClC-7 Cl-/H+ antiporter and the HV1 proton channel. Here we present a detailed mathematical model of osteoclast acidification that includes the influence of many of the key regulatory proteins. The primary enzyme responsible for acidification is the vacuolar H+-ATPase (V-ATPase), which pumps protons from the cytoplasm into the pit. Unlike the acidification of small lysosomes, the pit is so large that protons become depleted from the cytoplasm. Hence, proton buffering and production in the cytoplasm by carbonic anhydrase II (CAII) is potentially important for proper acidification. We employ an ordinary differential equations (ODE)-based model that accounts for the changes in ionic species in the cytoplasm and the resorptive pit. Additionally, our model tracks ionic flow between the cytoplasm and the extracellular solution surrounding the cell. Whenever possible, the properties of individual channels and transporters are calibrated based on electrophysiological measurements, and physical properties of the cell, such as buffering capacity, surface areas, and volumes, are estimated based on available data. Our model reproduces many of the experimental findings regarding the role of key proteins in the acidification process, and it allows us to estimate, among other things, number of active pumps, protons moved, and the influence of particular mutations implicated in disease.
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Affiliation(s)
- Frank V Marcoline
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Yoichi Ishida
- Department of Philosophy, Ohio University, Athens, OH 45701, USA
| | - Joseph A Mindell
- Membrane Transport Biophysics Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Smita Nayak
- Swedish Center for Research and Innovation, Swedish Health Services, Seattle, WA 98122, USA
| | - Michael Grabe
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA.
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10
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Matsuki Y, Iwamoto M, Mita K, Shigemi K, Matsunaga S, Oiki S. Rectified Proton Grotthuss Conduction Across a Long Water-Wire in the Test Nanotube of the Polytheonamide B Channel. J Am Chem Soc 2016; 138:4168-77. [DOI: 10.1021/jacs.5b13377] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yuka Matsuki
- Department
of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
- Department
of Anesthesiology and Reanimatology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Masayuki Iwamoto
- Department
of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Kenichiro Mita
- Department
of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
- Department
of Anesthesiology and Reanimatology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Kenji Shigemi
- Department
of Anesthesiology and Reanimatology, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Shigeki Matsunaga
- Laboratory
of Aquatic Natural Products Chemistry, Graduate School of Agricultural
and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shigetoshi Oiki
- Department
of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
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Kuno M, Li G, Moriura Y, Hino Y, Kawawaki J, Sakai H. Acid-inducible proton influx currents in the plasma membrane of murine osteoclast-like cells. Pflugers Arch 2016; 468:837-47. [PMID: 26843093 DOI: 10.1007/s00424-016-1796-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/02/2016] [Accepted: 01/25/2016] [Indexed: 01/20/2023]
Abstract
Acidification of the resorption pits, which is essential for dissolving bone, is produced by secretion of protons through vacuolar H(+)-ATPases in the plasma membrane of bone-resorbing cells, osteoclasts. Consequently, osteoclasts face highly acidic extracellular environments, where the pH gradient across the plasma membrane could generate a force driving protons into the cells. Proton influx mechanisms during the acid exposure are largely unknown, however. In this study, we investigated extracellular-acid-inducible proton influx currents in osteoclast-like cells derived from a macrophage cell line (RAW264). Decreasing extracellular pH to <5.5 induced non-ohmic inward currents. The reversal potentials depended on the pH gradients across the membrane and were independent of concentrations of Na(+), Cl(-), and HCO3 (-), suggesting that they were carried largely by protons. The acid-inducible proton influx currents were not inhibited by amiloride, a widely used blocker for cation channels/transporters, or by 4,4'-diisothiocyanato-2,2'-stilbenesulfonate(DIDS) which blocks anion channels/transporters. Additionally, the currents were not significantly affected by V-ATPase inhibitors, bafilomycin A1 and N,N'-dicyclohexylcarbodiimide. Extracellular Ca(2+) (10 mM) did not affect the currents, but 1 mM ZnCl2 decreased the currents partially. The intracellular pH in the vicinity of the plasma membrane was dropped by the acid-inducible H(+) influx currents, which caused overshoot of the voltage-gated H(+) channels after removal of acids. The H(+) influx currents were smaller in undifferentiated, mononuclear RAW cells and were negligible in COS7 cells. These data suggest that the acid-inducible H(+) influx (H(+) leak) pathway may be an additional mechanism modifying the pH environments of osteoclasts upon exposure to strong acids.
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Affiliation(s)
- Miyuki Kuno
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan.
| | - Guangshuai Li
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Yoshie Moriura
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Yoshiko Hino
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
| | - Junko Kawawaki
- Central Laboratory, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka, 545-8585, Japan
| | - Hiromu Sakai
- Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka, 545-8585, Japan
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Abstract
Hv1 is a voltage-gated proton-selective channel that plays critical parts in host defense, sperm motility, and cancer progression. Hv1 contains a conserved voltage-sensor domain (VSD) that is shared by a large family of voltage-gated ion channels, but it lacks a pore domain. Voltage sensitivity and proton conductivity are conferred by a unitary VSD that consists of four transmembrane helices. The architecture of Hv1 differs from that of cation channels that form a pore in the center among multiple subunits (as in most cation channels) or homologous repeats (as in voltage-gated sodium and calcium channels). Hv1 forms a dimer in which a cytoplasmic coiled coil underpins the two protomers and forms a single, long helix that is contiguous with S4, the transmembrane voltage-sensing segment. The closed-state structure of Hv1 was recently solved using X-ray crystallography. In this article, we discuss the gating mechanism of Hv1 and focus on cooperativity within dimers and their sensitivity to metal ions.
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Affiliation(s)
- Yasushi Okamura
- Department of Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan; , ,
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Molecular determinants of Hv1 proton channel inhibition by guanidine derivatives. Proc Natl Acad Sci U S A 2014; 111:9971-6. [PMID: 24912149 DOI: 10.1073/pnas.1324012111] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The voltage-gated proton channel Hv1 plays important roles in proton extrusion, pH homeostasis, and production of reactive oxygen species in a variety of cell types. Excessive Hv1 activity increases proliferation and invasiveness in cancer cells and worsens brain damage in ischemic stroke. The channel is composed of two subunits, each containing a proton-permeable voltage-sensing domain (VSD) and lacking the pore domain typical of other voltage-gated ion channels. We have previously shown that the compound 2-guanidinobenzimidazole (2GBI) inhibits Hv1 proton conduction by binding to the VSD from its intracellular side. Here, we examine the binding affinities of a series of 2GBI derivatives on human Hv1 channels mutated at positions located in the core of the VSD and apply mutant cycle analysis to determine how the inhibitor interacts with the channel. We identify four Hv1 residues involved in the binding: aspartate 112, phenylalanine 150, serine 181, and arginine 211. 2GBI appears to be oriented in the binding site with its benzo ring pointing to F150, its imidazole ring inserted between residue D112 and residues S181 and R211, and the guanidine group positioned in the proximity of R211. We also identify a modified version of 2GBI that is able to reach the binding site on Hv1 from the extracellular side of the membrane. Understanding how compounds like 2GBI interact with the Hv1 channel is an important step to the development of pharmacological treatments for diseases caused by Hv1 hyperactivity.
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Fujiwara Y, Okamura Y. Temperature-sensitive gating of voltage-gated proton channels. CURRENT TOPICS IN MEMBRANES 2014; 74:259-92. [PMID: 25366240 DOI: 10.1016/b978-0-12-800181-3.00010-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The voltage-gated proton channel (Hv) mediates robust proton transport down the proton electrochemical gradient. Hv is mainly expressed in immune cells, including neutrophils and macrophages, the physiological functions of which are temperature sensitive. In those cells, Hv plays key roles in the regulation of reactive oxygen species production and pH homeostasis. Proton transport through Hv is regulated by both the membrane potential and the pH difference across the cell membrane. Earlier studies showed that the properties of Hv, including proton conductance and gating, are highly temperature dependent. Hv consists of a voltage sensor domain involved in both voltage sensing and proton permeation and a C-terminal coiled coil region. Although the channel's activities are innate to the protomers, normally two protomers assemble as a dimer via interaction between C-terminal coiled coils. We recently discovered that the coiled-coil region of Hv dissociates at around room temperature, and that subtle changes in the coiled-coil region affect temperature-sensitive gating. In this chapter, we describe the physiological functions and molecular mechanisms of Hv, focusing mainly on the structure and thermosensitive properties of Hv.
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Affiliation(s)
- Yuichiro Fujiwara
- Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yasushi Okamura
- Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University, Suita, Japan
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