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Zhang K, Wang L, Liu Z, Geng B, Teng Y, Liu X, Yi Q, Yu D, Chen X, Zhao D, Xia Y. Mechanosensory and mechanotransductive processes mediated by ion channels in articular chondrocytes: Potential therapeutic targets for osteoarthritis. Channels (Austin) 2021; 15:339-359. [PMID: 33775217 PMCID: PMC8018402 DOI: 10.1080/19336950.2021.1903184] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 02/06/2023] Open
Abstract
Articular cartilage consists of an extracellular matrix including many proteins as well as embedded chondrocytes. Articular cartilage formation and function are influenced by mechanical forces. Hind limb unloading or simulated microgravity causes articular cartilage loss, suggesting the importance of the healthy mechanical environment in articular cartilage homeostasis and implying a significant role of appropriate mechanical stimulation in articular cartilage degeneration. Mechanosensitive ion channels participate in regulating the metabolism of articular chondrocytes, including matrix protein production and extracellular matrix synthesis. Mechanical stimuli, including fluid shear stress, stretch, compression and cell swelling and decreased mechanical conditions (such as simulated microgravity) can alter the membrane potential and regulate the metabolism of articular chondrocytes via transmembrane ion channel-induced ionic fluxes. This process includes Ca2+ influx and the resulting mobilization of Ca2+ that is due to massive released Ca2+ from stores, intracellular cation efflux and extracellular cation influx. This review brings together published information on mechanosensitive ion channels, such as stretch-activated channels (SACs), voltage-gated Ca2+ channels (VGCCs), large conductance Ca2+-activated K+ channels (BKCa channels), Ca2+-activated K+ channels (SKCa channels), voltage-activated H+ channels (VAHCs), acid sensing ion channels (ASICs), transient receptor potential (TRP) family channels, and piezo1/2 channels. Data based on epithelial sodium channels (ENaCs), purinergic receptors and N-methyl-d-aspartate (NMDA) receptors are also included. These channels mediate mechanoelectrical physiological processes essential for converting physical force signals into biological signals. The primary channel-mediated effects and signaling pathways regulated by these mechanosensitive ion channels can influence the progression of osteoarthritis during the mechanosensory and mechanoadaptive process of articular chondrocytes.
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Affiliation(s)
- Kun Zhang
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Lifu Wang
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Zhongcheng Liu
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Bin Geng
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Yuanjun Teng
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Xuening Liu
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Qiong Yi
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Dechen Yu
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Xiangyi Chen
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Dacheng Zhao
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
| | - Yayi Xia
- Department of Orthopedics, Orthopaedics Key Laboratory of Gansu Province, Lanzhou University Second Hospital, Lanzhou Gansu, China
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Wierzcholski K, Miszczak A. Mathematical principles and methods of biological surface lubrication with phospholipids bilayers. Biosystems 2018; 178:32-40. [PMID: 30448537 DOI: 10.1016/j.biosystems.2018.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/05/2018] [Accepted: 11/07/2018] [Indexed: 11/29/2022]
Abstract
This paper presents a mini-review of investigations performed by the authors in the field of hydrodynamic theory of lubrication of biological systems and synthetic processing of results to indicate the influence of biologically live material properties on biological liquid viscosity variations. The goal of the presented study was to demonstrate a new principle of a general mathematical theory applied to the mechanism of hydrodynamic lubrication of human joint cartilage surfaces with phospholipids bilayer and to indicate analytical solutions of hydrodynamic pressure, temperature and bio-fluid velocity components. Moreover, 3D variations of dynamic synovial fluid viscosity are assessed, particularly its variations across the entire film thickness. A new 3D analytical and numerical model has been elaborated on the basis of tribology methods, based on the assumptions of an ultra-thin boundary layer of non-Newtonian fluid. The analysed elements also included phospholipid concentrations, power hydrogen ion and collagen fiber concentrations in synovial, biological fluids, as well as electrostatic field, cartilage or biological surface wettability. The obtained results of our analysis demonstrate relationships which occur among hydrodynamic pressure, human joint load carrying capacity and phospholipid bilayer in the cartilage superficial layer. According to the best knowledge of the Authors, the obtained results may find applications in a broad scope of spatiotemporal models in biology and health science.
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Affiliation(s)
- Krzysztof Wierzcholski
- Technical University of Koszalin, Institute of Technology and Education, Śniadeckich 2, 75-453 Koszalin, Poland.
| | - Andrzej Miszczak
- Gdynia Maritime University, Morska 81-87, 81-225 Gdynia, Poland.
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3
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DeCoursey TE. The intimate and controversial relationship between voltage-gated proton channels and the phagocyte NADPH oxidase. Immunol Rev 2017; 273:194-218. [PMID: 27558336 DOI: 10.1111/imr.12437] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
One of the most fascinating and exciting periods in my scientific career entailed dissecting the symbiotic relationship between two membrane transporters, the Nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase complex and voltage-gated proton channels (HV 1). By the time I entered this field, there had already been substantial progress toward understanding NADPH oxidase, but HV 1 were known only to a tiny handful of cognoscenti around the world. Having identified the first proton currents in mammalian cells in 1991, I needed to find a clear function for these molecules if the work was to become fundable. The then-recent discoveries of Henderson, Chappell, and colleagues in 1987-1988 that led them to hypothesize interactions of both molecules during the respiratory burst of phagocytes provided an excellent opportunity. In a nutshell, both transporters function by moving electrical charge across the membrane: NADPH oxidase moves electrons and HV 1 moves protons. The consequences of electrogenic NADPH oxidase activity on both membrane potential and pH strongly self-limit this enzyme. Fortunately, both consequences specifically activate HV 1, and HV 1 activity counteracts both consequences, a kind of yin-yang relationship. Notwithstanding a decade starting in 1995 when many believed the opposite, these are two separate molecules that function independently despite their being functionally interdependent in phagocytes. The relationship between NADPH oxidase and HV 1 has become a paradigm that somewhat surprisingly has now extended well beyond the phagocyte NADPH oxidase - an industrial strength producer of reactive oxygen species (ROS) - to myriad other cells that produce orders of magnitude less ROS for signaling purposes. These cells with their seven NADPH oxidase (NOX) isoforms provide a vast realm of mechanistic obscurity that will occupy future studies for years to come.
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Affiliation(s)
- Thomas E DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL, USA
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4
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Servin-Vences MR, Moroni M, Lewin GR, Poole K. Direct measurement of TRPV4 and PIEZO1 activity reveals multiple mechanotransduction pathways in chondrocytes. eLife 2017; 6. [PMID: 28135189 PMCID: PMC5279942 DOI: 10.7554/elife.21074] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/03/2017] [Indexed: 12/24/2022] Open
Abstract
The joints of mammals are lined with cartilage, comprised of individual chondrocytes embedded in a specialized extracellular matrix. Chondrocytes experience a complex mechanical environment and respond to changing mechanical loads in order to maintain cartilage homeostasis. It has been proposed that mechanically gated ion channels are of functional importance in chondrocyte mechanotransduction; however, direct evidence of mechanical current activation in these cells has been lacking. We have used high-speed pressure clamp and elastomeric pillar arrays to apply distinct mechanical stimuli to primary murine chondrocytes, stretch of the membrane and deflection of cell-substrate contacts points, respectively. Both TRPV4 and PIEZO1 channels contribute to currents activated by stimuli applied at cell-substrate contacts but only PIEZO1 mediates stretch-activated currents. These data demonstrate that there are separate, but overlapping, mechanoelectrical transduction pathways in chondrocytes.
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Affiliation(s)
| | - Mirko Moroni
- Department of Neuroscience, Max Delbruck Center for Molecular Medicine, Berlin, Germany
| | - Gary R Lewin
- Department of Neuroscience, Max Delbruck Center for Molecular Medicine, Berlin, Germany
| | - Kate Poole
- Department of Neuroscience, Max Delbruck Center for Molecular Medicine, Berlin, Germany.,Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia.,EMBL Australia node for Single Molecule Sciences, School of Medical Sciences, University of New South Wales, Sydney, Australia
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5
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Held K, Voets T, Vriens J. Signature and Pathophysiology of Non-canonical Pores in Voltage-Dependent Cation Channels. Rev Physiol Biochem Pharmacol 2016; 170:67-99. [DOI: 10.1007/112_2015_5003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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6
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Proton pump (H+/K+-ATPase) expression in human larynx. Auris Nasus Larynx 2015; 42:458-62. [DOI: 10.1016/j.anl.2015.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/27/2015] [Accepted: 04/30/2015] [Indexed: 12/23/2022]
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Castillo K, Pupo A, Baez-Nieto D, Contreras GF, Morera FJ, Neely A, Latorre R, Gonzalez C. Voltage-gated proton (H(v)1) channels, a singular voltage sensing domain. FEBS Lett 2015; 589:3471-8. [PMID: 26296320 DOI: 10.1016/j.febslet.2015.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 12/28/2022]
Abstract
The main role of voltage-gated proton channels (Hv1) is to extrude protons from the intracellular milieu when, mediated by different cellular processes, the H(+) concentration increases. Hv1 are exquisitely selective for protons and their structure is homologous to the voltage sensing domain (VSD) of other voltage-gated ion channels like sodium, potassium, and calcium channels. In clear contrast to the classical voltage-dependent channels, Hv1 lacks a pore domain and thus permeation necessarily occurs through the voltage sensing domain. Hv1 channels are activated by depolarizing voltages, and increases in internal proton concentration. It has been proposed that local conformational changes of the transmembrane segment S4, driven by depolarization, trigger the molecular rearrangements that open Hv1. However, it is still unclear how the electromechanical coupling is achieved between the VSD and the potential pore, allowing the proton flux from the intracellular to the extracellular side. Here we provide a revised view of voltage activation in Hv1 channels, offering a comparative scenario with other voltage sensing channels domains.
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Affiliation(s)
- Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - David Baez-Nieto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Gustavo F Contreras
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Francisco J Morera
- Institute of Pharmacology and Morphophysiology, Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Alan Neely
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile.
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile.
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Synergy between Piezo1 and Piezo2 channels confers high-strain mechanosensitivity to articular cartilage. Proc Natl Acad Sci U S A 2014; 111:E5114-22. [PMID: 25385580 DOI: 10.1073/pnas.1414298111] [Citation(s) in RCA: 259] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Diarthrodial joints are essential for load bearing and locomotion. Physiologically, articular cartilage sustains millions of cycles of mechanical loading. Chondrocytes, the cells in cartilage, regulate their metabolic activities in response to mechanical loading. Pathological mechanical stress can lead to maladaptive cellular responses and subsequent cartilage degeneration. We sought to deconstruct chondrocyte mechanotransduction by identifying mechanosensitive ion channels functioning at injurious levels of strain. We detected robust expression of the recently identified mechanosensitive channels, PIEZO1 and PIEZO2. Combined directed expression of Piezo1 and -2 sustained potentiated mechanically induced Ca(2+) signals and electrical currents compared with single-Piezo expression. In primary articular chondrocytes, mechanically evoked Ca(2+) transients produced by atomic force microscopy were inhibited by GsMTx4, a PIEZO-blocking peptide, and by Piezo1- or Piezo2-specific siRNA. We complemented the cellular approach with an explant-cartilage injury model. GsMTx4 reduced chondrocyte death after mechanical injury, suggesting a possible therapy for reducing cartilage injury and posttraumatic osteoarthritis by attenuating Piezo-mediated cartilage mechanotransduction of injurious strains.
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9
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Gadomski A, Bełdowski P, Rubì JM, Urbaniak W, Augé WK, Santamarìa-Holek I, Pawlak Z. Some conceptual thoughts toward nanoscale oriented friction in a model of articular cartilage. Math Biosci 2013; 244:188-200. [PMID: 23707486 DOI: 10.1016/j.mbs.2013.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 01/25/2023]
Abstract
This work presents a conceptual framework as to how a deficit in the synovial-fluid content, exemplified by hyaluronan or any other amphiphilic species, is capable of decisively altering the complex lubrication and wear conditions observed clinically in articular cartilage. The effect is revealed in (non)stationary regimes if the cartilage is subjected to some normal periodic load, revealing over its exploitation time increasingly dissipative, in general entropy-addressing, characteristics. It can be hypothesized that a Grotthuss-type proton transport physiology-concerning mechanism in channel-like, phospholipid-water cartilage's articulating nanospaces will be responsible for the expression of the lubrication mode. The corresponding wear involving overall change is then manifested adequately in the stationary regime, and in a viable system-parametric correlation with its lubrication counterpart. Certain analytic formulae for the nanoscale oriented coefficient of friction, involving generically H-bonds breaking mechanism, and pointing to some local-viscosity context, have been proposed for fitting the experimental data and clinical observations involving proton management at articular cartilage surfaces.
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Affiliation(s)
- Adam Gadomski
- University of Technology and Life Sciences, Institute of Mathematics and Physics, PL-85796 Bydgoszcz, Poland
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10
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Abstract
The degenerative joint disease osteoarthritis (OA) is the most prevalent form of chronic musculoskeletal disease worldwide, and it commonly afflicts the elderly population. OA-induced impairment of joint function can debilitate normal physical activity, and in more severe cases, it can lead to complete joint destruction and loss of independence or even mobility. The pathophysiology of OA remains to be fully elucidated, despite the extensive research efforts into this complex disease. Studies have revealed that reactive oxygen species (ROS) can contribute to the onset and progression of OA by inducing indispensable chondrocyte death and matrix degradation. However, ROS are also key components of many normal physiological processes, and at moderate levels, they act as indispensable second messengers. This review focuses on the dual role of ROS in cartilage, with the aim of gaining insights into how ROS can be regulated such that its beneficial effects are maintained and its detrimental effects are eliminated.
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11
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Ganguly K, McRury ID, Goodwin PM, Morgan RE, Augé WK. Targeted In Situ Biosynthetic Transcriptional Activation in Native Surface-Level Human Articular Chondrocytes during Lesion Stabilization. Cartilage 2012; 3:141-55. [PMID: 26069627 PMCID: PMC4297128 DOI: 10.1177/1947603511426881] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Safe articular cartilage lesion stabilization is an important early surgical intervention advance toward mitigating articular cartilage disease burden. While short-term chondrocyte viability and chondrosupportive matrix modification have been demonstrated within tissue contiguous to targeted removal of damaged articular cartilage, longer term tissue responses require evaluation to further clarify treatment efficacy. The purpose of this study was to examine surface chondrocyte responses within contiguous tissue after lesion stabilization. METHODS Nonablation radiofrequency lesion stabilization of human cartilage explants obtained during knee replacement was performed for surface fibrillation. Time-dependent chondrocyte viability, nuclear morphology and cell distribution, and temporal response kinetics of matrix and chaperone gene transcription indicative of differentiated chondrocyte function were evaluated in samples at intervals to 96 hours after treatment. RESULTS Subadjacent surface articular cartilage chondrocytes demonstrated continued viability for 96 hours after treatment, a lack of increased nuclear fragmentation or condensation, persistent nucleic acid production during incubation reflecting cellular assembly behavior, and transcriptional up-regulation of matrix and chaperone genes indicative of retained biosynthetic differentiated cell function. CONCLUSIONS The results of this study provide further evidence of treatment efficacy and suggest the possibility to manipulate or induce cellular function, thereby recruiting local chondrocytes to aid lesion recovery. Early surgical intervention may be viewed as a tissue rescue, allowing articular cartilage to continue displaying biological responses appropriate to its function rather than converting to a tissue ultimately governed by the degenerative material property responses of matrix failure. Early intervention may positively impact the late changes and reduce disease burden of damaged articular cartilage.
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Affiliation(s)
| | | | | | | | - Wayne K. Augé
- NuOrtho Surgical Inc., Fall River, MA, USA,Center for Orthopaedic and Sports Performance Research Inc., Santa Fe, NM, USA
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12
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Abstract
Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely, the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn(2+) (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B-lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H(+) for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens.
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Affiliation(s)
- Thomas E Decoursey
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois, USA.
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Barrett-Jolley R, Lewis R, Fallman R, Mobasheri A. The emerging chondrocyte channelome. Front Physiol 2010; 1:135. [PMID: 21423376 PMCID: PMC3059965 DOI: 10.3389/fphys.2010.00135] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/09/2010] [Indexed: 11/18/2022] Open
Abstract
Chondrocytes are the resident cells of articular cartilage and are responsible for synthesizing a range of collagenous and non-collagenous extracellular matrix macromolecules. Whilst chondrocytes exist at low densities in the tissue (1-10% of the total tissue volume in mature cartilage) they are extremely active cells and are capable of responding to a range of mechanical and biochemical stimuli. These responses are necessary for the maintenance of viable cartilage and may be compromised in inflammatory diseases such as arthritis. Although chondrocytes are non-excitable cells their plasma membrane contains a rich complement of ion channels. This diverse channelome appears to be as complex as one might expect to find in excitable cells although, in the case of chondrocytes, their functions are far less well understood. The ion channels so far identified in chondrocytes include potassium channels (K(ATP), BK, K(v), and SK), sodium channels (epithelial sodium channels, voltage activated sodium channels), transient receptor potential calcium or non-selective cation channels and chloride channels. In this review we describe this emerging channelome and discuss the possible functions of a range of chondrocyte ion channels.
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Affiliation(s)
- Richard Barrett-Jolley
- Musculoskeletal Research Group, Department of Comparative Molecular Medicine, School of Veterinary Science, University of LiverpoolLiverpool, UK
| | - Rebecca Lewis
- Musculoskeletal Research Group, Department of Comparative Molecular Medicine, School of Veterinary Science, University of LiverpoolLiverpool, UK
| | - Rebecca Fallman
- Musculoskeletal Research Group, Department of Comparative Molecular Medicine, School of Veterinary Science, University of LiverpoolLiverpool, UK
| | - Ali Mobasheri
- Musculoskeletal Research Group, Division of Veterinary Medicine, School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of NottinghamNottingham, Leicestershire, UK
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Funabashi K, Ohya S, Yamamura H, Hatano N, Muraki K, Giles W, Imaizumi Y. Accelerated Ca2+ entry by membrane hyperpolarization due to Ca2+-activated K+ channel activation in response to histamine in chondrocytes. Am J Physiol Cell Physiol 2010; 298:C786-97. [DOI: 10.1152/ajpcell.00469.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In articular cartilage inflammation, histamine release from mast cells is a key event. It can enhance cytokine production and matrix synthesis and also promote cell proliferation by stimulating chondrocytes. In this study, the functional impact of Ca2+-activated K+ (KCa) channels in the regulation of intracellular Ca2+ concentration ([Ca2+]i) in chondrocytes in response to histamine was examined using OUMS-27 cells, as a model of chondrocytes derived from human chondrosarcoma. Application of histamine induced a significant [Ca2+]i rise and also membrane hyperpolarization, and both effects were mediated by the stimulation of H1 receptors. The histamine-induced membrane hyperpolarization was attenuated to ∼50% by large-conductance KCa (BK) channel blockers, and further reduced by intermediate (IK) and small conductance KCa (SK) channel blockers. The tonic component of histamine-induced [Ca2+]i rise strongly depended on the presence of extracellular Ca2+ ([Ca2+]o) and was markedly reduced by La3+ or Gd3+ but not by nifedipine. It was significantly attenuated by BK channel blockers, and further blocked by the cocktail of BK, IK, and SK channel blockers. The KCa blocker cocktail also significantly reduced the store-operated Ca2+ entry (SOCE), which was induced by Ca2+ addition after store-depletion by thapsigargin in [Ca2+]o free solution. Our results demonstrate that the histamine-induced membrane hyperpolarization in chondrocytes due to KCa channel activation contributes to sustained Ca2+ entry mainly through SOCE channels in OUMS-27 cells. Thus, KCa channels appear to play an important role in the positive feedback mechanism of [Ca2+]i regulation in chondrocytes in the presence of articular cartilage inflammation.
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Affiliation(s)
- Kenji Funabashi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Susumu Ohya
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya, Japan; and
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya, Japan; and
| | - Wayne Giles
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
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Abstract
Osteoarthritis is often a progressive and disabling disease, which occurs in the setting of a variety of risk factors--such as advancing age, obesity, and trauma--that conspire to incite a cascade of pathophysiologic events within joint tissues. An important emerging theme in osteoarthritis is a broadening of focus from a disease of cartilage to one of the 'whole joint'. The synovium, bone, and cartilage are each involved in pathologic processes that lead to progressive joint degeneration. Additional themes that have emerged over the past decade are novel mechanisms of cartilage degradation and repair, the relationship between biomechanics and biochemical pathways, the importance of inflammation, and the role played by genetics. In this review we summarize current scientific understanding of osteoarthritis and examine the pathobiologic mechanisms that contribute to progressive disease.
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Affiliation(s)
- Steven B Abramson
- Division of Rheumatology, NYU School of Medicine, NYU Hospital for Joint Diseases, New York, NY 10003, USA.
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16
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Abstract
The history of research on voltage-gated proton channels is recounted, from their proposed existence in dinoflagellates by Hastings in 1972 and their demonstration in snail neurons by Thomas and Meech in 1982 to the discovery in 2006 (after a decade of controversy) of genes that unequivocally code for proton channels. Voltage-gated proton channels are perfectly selective for protons, conduct deuterons half as well, and the conductance is strongly temperature dependent. These properties are consistent with a conduction mechanism involving hydrogen-bonded-chain transfer, in which the selectivity filter is a titratable amino acid residue. Channel opening is regulated stringently by pH such that only outward current is normally activated. Main functions of proton channels include acid extrusion from cells and charge compensation for the electrogenic activity of the phagocyte NADPH oxidase. Genetic approaches hold the promise of rapid progress in the near future.
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Affiliation(s)
- T E DeCoursey
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 W. Harrison, Chicago, Illinois 60612, USA.
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17
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Cheng YM, Kelly T, Church J. Potential contribution of a voltage-activated proton conductance to acid extrusion from rat hippocampal neurons. Neuroscience 2007; 151:1084-98. [PMID: 18201832 DOI: 10.1016/j.neuroscience.2007.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 11/23/2007] [Accepted: 12/07/2007] [Indexed: 11/27/2022]
Abstract
We examined the potential contribution of a voltage-gated proton conductance (gH+) to acid extrusion from cultured postnatal rat hippocampal neurons. In neurons loaded with Ca2+- and/or pH-sensitive fluorophores, transient exposures to 25-139.5 mM external K+ (K+o) or 20 microM veratridine in the presence of 2 mM Ca2+o (extracellular pH (pHo) constant at 7.35) caused reversible increases and decreases in intracellular free calcium concentration ([Ca2+]i) and intracellular pH (pHi), respectively. In contrast, under external Ca2+-free conditions, the same stimuli failed to affect [Ca2+]i but caused an increase in pHi, the magnitude of which was related to the [K+]o applied and the change in membrane potential. Consistent with the properties of gH+s in other cell types, the magnitude of the rise in pHi observed in the absence of external Ca2+ was not affected by the removal of external Na+ but was sensitive to external Zn2+ and temperature and was dependent on the measured transmembrane pH gradient (DeltapHmemb). Increasing DeltapH(memb) by pretreatment with carbonylcyanide-p-trifluoromethoxyphenylhydrazone augmented both the high-[K+]o-evoked rise in pHi and the Zn2+-sensitive component of the rise in pHi, suggestive of increased acid extrusion via a gH+. The inhibitory effect of Zn2+ at a given DeltapHmemb was further enhanced by increasing pHo from 7.35-7.8, consistent with a pHo-dependent inhibition of the putative gH+ by Zn2+. Under conditions designed to isolate H+ currents, a voltage-dependent outward current was recorded from whole-cell patch-clamped neurons. Although the outward current appeared to show some selectivity for protons, it was not sensitive to Zn2+ or temperature and the H+-selective component could not be separated from a larger conductance of unknown selectivity. Nonetheless, taken together, the results suggest that a Zn2+-sensitive proton conductive pathway is present in rat hippocampal neurons and contributes to H+ efflux under depolarizing conditions.
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Affiliation(s)
- Y M Cheng
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
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Gibson JS, Milner PI, White R, Fairfax TPA, Wilkins RJ. Oxygen and reactive oxygen species in articular cartilage: modulators of ionic homeostasis. Pflugers Arch 2007; 455:563-73. [PMID: 17849146 DOI: 10.1007/s00424-007-0310-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 06/20/2007] [Indexed: 11/26/2022]
Abstract
Articular cartilage is an avascular tissue dependent on diffusion mainly from synovial fluid to service its metabolic requirements. Levels of oxygen (O(2)) in the tissue are low, with estimates of between 1 and 6%. Metabolism is largely, if not entirely, glycolytic, with little capacity for oxidative phosphorylation. Notwithstanding, the tissue requires O(2) and consumes it, albeit at low rates. Changes in O(2) tension also have profound effects on chondrocytes affecting phenotype, gene expression, and morphology, as well as response to, and production of, cytokines. Although chondrocytes can survive prolonged anoxia, low O(2) levels have significant metabolic effects, inhibiting glycolysis (the negative Pasteur effect), and also notably matrix production. Why this tissue should respond so markedly to reduction in O(2) tension remains a paradox. Ion homeostasis in articular chondrocytes is also markedly affected by the extracellular matrix in which the cells reside. Recent work has shown that ion homeostasis also responds to changes in O(2) tension, in such a way as to produce significant effects on cell function. For this purpose, O(2) probably acts via alteration in levels of reactive oxygen species. We discuss the possibility that O(2) consumption by this tissue is required to maintain levels of ROS, which are then used physiologically as an intracellular signalling device. This postulate may go some way towards explaining why the tissue is dependent on O(2) and why its removal has such marked effects. Understanding the role of oxygen has implications for disease states in which O(2) or ROS levels may be perturbed.
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Affiliation(s)
- J S Gibson
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, England
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