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Kamkin AG, Kamkina OV, Kazansky VE, Mitrokhin VM, Bilichenko A, Nasedkina EA, Shileiko SA, Rodina AS, Zolotareva AD, Zolotarev VI, Sutyagin PV, Mladenov MI. Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca 2+current. Biol Direct 2023; 18:70. [PMID: 37899484 PMCID: PMC10614344 DOI: 10.1186/s13062-023-00427-0] [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: 06/19/2023] [Accepted: 10/13/2023] [Indexed: 10/31/2023] Open
Abstract
BACKGROUND The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through CaV1.2 channels under cell stretching using the whole-cell patch-clamp method. RESULTS Among channels that showed mechanosensitivity, significant amounts of TRPM7, TRPC1, and TRPM4 transcripts were found. We suppose that the recorded L-type Ca2+ current is probably expressed through CaV1.2. Furthermore, stretching cells by 6, 8, and 10 μm, which increases ISAC through the TRPM7, TRPC1, and TRPM4 channels, also decreased ICa,L through the CaV1.2 channels in K+ in/K+ out, Cs+ in/K+ out, K+ in/Cs+ out, and Cs+ in/Cs+ out solutions. The application of a nonspecific ISAC blocker, Gd3+, during cell stretching eliminated ISAC through nonselective cation channels and ICa,L through CaV1.2 channels. Since the response to Gd3+ was maintained in Cs+ in/Cs+ out solutions, we suggest that voltage-gated CaV1.2 channels in the ventricular myocytes of adult rats also exhibit mechanosensitive properties. CONCLUSIONS Our findings suggest that TRPM7, TRPC1, and TRPM4 channels represent stretch-activated nonselective cation channels in rat ventricular myocytes. Probably the CaV1.2 channels in these cells exhibit mechanosensitive properties. Our results provide insight into the molecular mechanisms underlying stretch-induced responses in rat ventricular myocytes, which may have implications for understanding cardiac physiology and pathophysiology.
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Affiliation(s)
- Andre G Kamkin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Olga V Kamkina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Viktor E Kazansky
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Vadim M Mitrokhin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Andrey Bilichenko
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Elizaveta A Nasedkina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Stanislav A Shileiko
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Anastasia S Rodina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Alexandra D Zolotareva
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Valentin I Zolotarev
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Pavel V Sutyagin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Mitko I Mladenov
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation.
- Faculty of Natural Sciences and Mathematics, Institute of Biology, "Ss. Cyril and Methodius" University, Skopje, North, Macedonia.
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2
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Zhou N, Li H, Xu J, Shen ZS, Tang M, Wang XH, Su WX, Sokabe M, Zhang Z, Tang QY. Two types of peptides derived from the neurotoxin GsMTx4 inhibit a mechanosensitive potassium channel by modifying the mechano-gate. J Biol Chem 2022; 298:102326. [PMID: 35933015 PMCID: PMC9449670 DOI: 10.1016/j.jbc.2022.102326] [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: 11/10/2021] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/14/2022] Open
Abstract
Atrial fibrillation is the most common sustained cardiac arrhythmia in humans. Current atrial fibrillation antiarrhythmic drugs have limited efficacy and carry the risk of ventricular proarrhythmia. GsMTx4, a mechanosensitive channel–selective inhibitor, has been shown to suppress arrhythmias through the inhibition of stretch-activated channels (SACs) in the heart. The cost of synthesizing this peptide is a major obstacle to clinical use. Here, we studied two types of short peptides derived from GsMTx4 for their effects on a stretch-activated big potassium channel (SAKcaC) from the heart. Type I, a 17-residue peptide (referred to as Pept 01), showed comparable efficacy, whereas type II (i.e., Pept 02), a 10-residue peptide, exerted even more potent inhibitory efficacy on SAKcaC compared with GsMTx4. We identified through mutagenesis important sequences required for peptide functions. In addition, molecular dynamics simulations revealed common structural features with a hydrophobic head followed by a positively charged protrusion that may be involved in peptide channel–lipid interactions. Furthermore, we suggest that these short peptides may inhibit SAKcaC through a specific modification to the mechanogate, as the inhibitory effects for both types of peptides were mostly abolished when tested with a mechano-insensitive channel variant (STREX-del) and a nonmechanosensitive big potassium (mouse Slo1) channel. These findings may offer an opportunity for the development of a new class of drugs in the treatment of cardiac arrhythmia generated by excitatory SACs in the heart.
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Affiliation(s)
- Nan Zhou
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Hui Li
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Jie Xu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Zhong-Shan Shen
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Mingxi Tang
- Department of Pathology, the Affiliated Hospital of Southwest Medical University, Taiping Road 25, Luzhou, Sichuan, China
| | - Xiao-Hui Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Wan-Xin Su
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University. Graduate School of Medicine, Nagoya, Japan; Kanazawa Institute of Technology, Nonoichi, Japan.
| | - Zhe Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, Jiangsu Province, China.
| | - Qiong-Yao Tang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, Jiangsu Province, China; NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, Jiangsu Province, China.
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3
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Sanghvi S, Szteyn K, Ponnalagu D, Sridharan D, Lam A, Hansra I, Chaudhury A, Majumdar U, Kohut AR, Gururaja Rao S, Khan M, Garg V, Singh H. Inhibition of BK Ca channels protects neonatal hearts against myocardial ischemia and reperfusion injury. Cell Death Dis 2022; 8:175. [PMID: 35393410 PMCID: PMC8989942 DOI: 10.1038/s41420-022-00980-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/15/2022] [Accepted: 03/23/2022] [Indexed: 11/30/2022]
Abstract
BKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes, which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL-positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.
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Affiliation(s)
- Shridhar Sanghvi
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Molecular Cellular and Developmental Biology, The Ohio State University, Columbus, OH, USA
| | - Kalina Szteyn
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Devasena Ponnalagu
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Divya Sridharan
- Department of Emergency Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Alexander Lam
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Inderjot Hansra
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ankur Chaudhury
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Uddalak Majumdar
- Center for Cardiovascular Research and The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Andrew R Kohut
- Department of Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, USA.,Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shubha Gururaja Rao
- Department of Pharmaceutical and Biomedical Sciences, The Raabe College of Pharmacy, Ohio Northern University, Ada, OH, USA
| | - Mahmood Khan
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Emergency Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Vidu Garg
- Center for Cardiovascular Research and The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Harpreet Singh
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA. .,Department of Molecular Cellular and Developmental Biology, The Ohio State University, Columbus, OH, USA.
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4
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Sanghvi S, Szteyn K, Ponnalagu D, Sridharan D, Lam A, Hansra I, Chaudhury A, Majumdar U, Kohut AR, Rao SG, Khan M, Garg V, Singh H. Inhibition of BK Ca channels protects neonatal hearts against myocardial ischemia and reperfusion injury.. [DOI: 10.1101/2021.11.02.466585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
AbstractBKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.
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5
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Barbeau S, Gilbert G, Cardouat G, Baudrimont I, Freund-Michel V, Guibert C, Marthan R, Vacher P, Quignard JF, Ducret T. Mechanosensitivity in Pulmonary Circulation: Pathophysiological Relevance of Stretch-Activated Channels in Pulmonary Hypertension. Biomolecules 2021; 11:biom11091389. [PMID: 34572602 PMCID: PMC8470538 DOI: 10.3390/biom11091389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/17/2021] [Accepted: 09/19/2021] [Indexed: 01/03/2023] Open
Abstract
A variety of cell types in pulmonary arteries (endothelial cells, fibroblasts, and smooth muscle cells) are continuously exposed to mechanical stimulations such as shear stress and pulsatile blood pressure, which are altered under conditions of pulmonary hypertension (PH). Most functions of such vascular cells (e.g., contraction, migration, proliferation, production of extracellular matrix proteins, etc.) depend on a key event, i.e., the increase in intracellular calcium concentration ([Ca2+]i) which results from an influx of extracellular Ca2+ and/or a release of intracellular stored Ca2+. Calcium entry from the extracellular space is a major step in the elevation of [Ca2+]i, involving a variety of plasmalemmal Ca2+ channels including the superfamily of stretch-activated channels (SAC). A common characteristic of SAC is that their gating depends on membrane stretch. In general, SAC are non-selective Ca2+-permeable cation channels, including proteins of the TRP (Transient Receptor Potential) and Piezo channel superfamily. As membrane mechano-transducers, SAC convert physical forces into biological signals and hence into a cell response. Consequently, SAC play a major role in pulmonary arterial calcium homeostasis and, thus, appear as potential novel drug targets for a better management of PH.
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Affiliation(s)
- Solène Barbeau
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Guillaume Gilbert
- ORPHY, UFR Sciences et Techniques, University of Brest, EA 4324, F-29238 Brest, France;
| | - Guillaume Cardouat
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Isabelle Baudrimont
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Véronique Freund-Michel
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Christelle Guibert
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Roger Marthan
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Pierre Vacher
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Jean-François Quignard
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
| | - Thomas Ducret
- Centre de Recherche Cardio-Thoracique de Bordeaux, Univ. Bordeaux, U1045, F-33600 Pessac, France; (S.B.); (G.C.); (I.B.); (V.F.-M.); (C.G.); (R.M.); (P.V.); (J.-F.Q.)
- INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33600 Pessac, France
- Correspondence:
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Szteyn K, Singh H. BK Ca Channels as Targets for Cardioprotection. Antioxidants (Basel) 2020; 9:antiox9080760. [PMID: 32824463 PMCID: PMC7463653 DOI: 10.3390/antiox9080760] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022] Open
Abstract
The large-conductance calcium- and voltage-activated K+ channel (BKCa) are encoded by the Kcnma1 gene. They are ubiquitously expressed in neuronal, smooth muscle, astrocytes, and neuroendocrine cells where they are known to play an important role in physiological and pathological processes. They are usually localized to the plasma membrane of the majority of the cells with an exception of adult cardiomyocytes, where BKCa is known to localize to mitochondria. BKCa channels couple calcium and voltage responses in the cell, which places them as unique targets for a rapid physiological response. The expression and activity of BKCa have been linked to several cardiovascular, muscular, and neurological defects, making them a key therapeutic target. Specifically in the heart muscle, pharmacological and genetic activation of BKCa channels protect the heart from ischemia-reperfusion injury and also facilitate cardioprotection rendered by ischemic preconditioning. The mechanism involved in cardioprotection is assigned to the modulation of mitochondrial functions, such as regulation of mitochondrial calcium, reactive oxygen species, and membrane potential. Here, we review the progress made on BKCa channels and cardioprotection and explore their potential roles as therapeutic targets for preventing acute myocardial infarction.
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Kravenska Y, Nieznanska H, Nieznanski K, Lukyanetz E, Szewczyk A, Koprowski P. The monomers, oligomers, and fibrils of amyloid-β inhibit the activity of mitoBK Ca channels by a membrane-mediated mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183337. [PMID: 32380169 DOI: 10.1016/j.bbamem.2020.183337] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 04/25/2020] [Accepted: 04/28/2020] [Indexed: 02/08/2023]
Abstract
A causative agent of Alzheimer's disease (AD) is a short amphipathic peptide called amyloid beta (Aβ). Aβ monomers undergo structural changes leading to their oligomerization or fibrillization. The monomers as well as all aggregated forms of Aβ, i.e., oligomers, and fibrils, can bind to biological membranes, thereby modulating membrane mechanical properties. It is also known that some isoforms of the large-conductance calcium-activated potassium (BKCa) channel, including the mitochondrial BKCa (mitoBKCa) channel, respond to mechanical changes in the membrane. Here, using the patch-clamp technique, we investigated the impact of full-length Aβ (Aβ1-42) and its fragment, Aβ25-35, on the activity of mitoBKCa channels. We found that all forms of Aβ inhibited the activity of the mitoBKCa channel in a concentration-dependent manner. Since monomers, oligomers, and fibrils of Aβ exhibit different molecular characteristics and structures, we hypothesized that the inhibition was not due to direct peptide-protein interactions but rather to membrane-binding of the Aβ peptides. Our findings supported this hypothesis by showing that Aβ peptides block mitoBKCa channels irrespective of the side of the membrane to which they are applied. In addition, we found that the enantiomeric peptide, D-Aβ1-42, demonstrated similar inhibitory activity towards mitoBKCa channels. As a result, we proposed a general model in which all Aβ forms i.e., monomers, oligomers, and amyloid fibrils, contribute to the progression of AD by exerting a modulatory effect on mechanosensitive membrane components.
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Affiliation(s)
- Yevheniia Kravenska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Pasteura str. 3, Warsaw 02-093, Poland; Department of Biophysics of Ion Channels, Bogomoletz Institute of Physiology NASU, Bogomoletz str. 4, Kyiv 01-024, Ukraine.
| | - Hanna Nieznanska
- Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology PAS, Pasteura str. 3, Warsaw 02-093, Poland
| | - Krzysztof Nieznanski
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology PAS, Pasteura str. 3, Warsaw 02-093, Poland
| | - Elena Lukyanetz
- Department of Biophysics of Ion Channels, Bogomoletz Institute of Physiology NASU, Bogomoletz str. 4, Kyiv 01-024, Ukraine
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Pasteura str. 3, Warsaw 02-093, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Pasteura str. 3, Warsaw 02-093, Poland
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Prenatal caffeine exposure induces down-regulation of the protein kinase A/ryanodine receptor/large-conductance Ca2+-activated K+ pathway in the cerebral arteries of old offspring rats. J Hypertens 2020; 38:679-691. [DOI: 10.1097/hjh.0000000000002303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Liu S, Gao X, Wu X, Yu Y, Yu Z, Zhao S, Zhao H. BK channels regulate calcium oscillations in ventricular myocytes on different substrate stiffness. Life Sci 2019; 235:116802. [PMID: 31472150 DOI: 10.1016/j.lfs.2019.116802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 01/29/2023]
Abstract
Substrate stiffness is essential for cell functions, but the mechanisms by which cell sense mechanical cues are still unclear. Here we show that the frequency and the amplitude of spontaneous Ca2+ oscillations were greater in chick cardiomyocytes cultured on the stiff substrates than that on the soft substrates. The spontaneous Ca2+ oscillations were increased on stiff substrates. However, an eliminated dependence of the Ca2+ oscillations on substrate stiffness was observed after applying blocker of the large-conductance Ca2+-activated K+ (BK) channels. In addition, the activity of BK channels in cardiomyocytes cultured on the stiff substrates was decreased. These results provide compelling evidences to show that BK channels are crucial in substrate stiffness-dependent regulation of the Ca2+ oscillation in cardiomyocytes.
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Affiliation(s)
- Sisi Liu
- Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing 100084, PR China
| | - Xiaohui Gao
- Department of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Yang Yu
- Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing 100084, PR China
| | - Zhang Yu
- Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing 100084, PR China
| | - Sui Zhao
- Affiliated High School of Tsinghua University, Beijing 100084, PR China
| | - Hucheng Zhao
- Institute of Biomechanics and Medical Engineering, School of Aerospace Engineering, Tsinghua University, Beijing 100084, PR China.
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10
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Li H, Xu J, Shen ZS, Wang GM, Tang M, Du XR, Lv YT, Wang JJ, Zhang FF, Qi Z, Zhang Z, Sokabe M, Tang QY. The neuropeptide GsMTx4 inhibits a mechanosensitive BK channel through the voltage-dependent modification specific to mechano-gating. J Biol Chem 2019; 294:11892-11909. [PMID: 31201274 DOI: 10.1074/jbc.ra118.005511] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
The cardiac mechanosensitive BK (Slo1) channels are gated by Ca2+, voltage, and membrane stretch. The neuropeptide GsMTx4 is a selective inhibitor of mechanosensitive (MS) channels. It has been reported to suppress stretch-induced cardiac fibrillation in the heart, but the mechanism underlying the specificity and even the targeting channel(s) in the heart remain elusive. Here, we report that GsMTx4 inhibits a stretch-activated BK channel (SAKcaC) in the heart through a modulation specific to mechano-gating. We show that membrane stretching increases while GsMTx4 decreases the open probability (P o) of SAKcaC. These effects were mostly abolished by the deletion of the STREX axis-regulated (STREX) exon located between RCK1 and RCK2 domains in BK channels. Single-channel kinetics analysis revealed that membrane stretch activates SAKcaC by prolonging the open-time duration (τO) and shortening the closed-time constant (τC). In contrast, GsMTx4 reversed the effects of membrane stretch, suggesting that GsMTx4 inhibits SAKcaC activity by interfering with mechano-gating of the channel. Moreover, GsMTx4 exerted stronger efficacy on SAKcaC under membrane-hyperpolarized/resting conditions. Molecular dynamics simulation study revealed that GsMTx4 appeared to have the ability to penetrate deeply within the bilayer, thus generating strong membrane deformation under the hyperpolarizing/resting conditions. Immunostaining results indicate that BK variants containing STREX are also expressed in mouse ventricular cardiomyocytes. Our results provide common mechanisms of peptide actions on MS channels and may give clues to therapeutic suppression of cardiac arrhythmias caused by excitatory currents through MS channels under hyper-mechanical stress in the heart.
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Affiliation(s)
- Hui Li
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Jie Xu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zhong-Shan Shen
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Guang-Ming Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Mingxi Tang
- Department of Pathology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Xiang-Rong Du
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Yan-Tian Lv
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Jing-Jing Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Fei-Fei Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zhi Qi
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiamen 361102, China
| | - Zhe Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Masahiro Sokabe
- ICORP Cell Mechanosensing, Japan Science and Technology Agency, Nagoya 466-8550, Japan .,Mechanobiology Laboratory, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Japan.,Department of Physiology, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Qiong-Yao Tang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China .,ICORP Cell Mechanosensing, Japan Science and Technology Agency, Nagoya 466-8550, Japan
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11
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Wawrzkiewicz-Jałowiecka A, Trybek P, Machura Ł, Dworakowska B, Grzywna ZJ. Mechanosensitivity of the BK Channels in Human Glioblastoma Cells: Kinetics and Dynamical Complexity. J Membr Biol 2018; 251:667-679. [PMID: 30094475 PMCID: PMC6244768 DOI: 10.1007/s00232-018-0044-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/02/2018] [Indexed: 01/31/2023]
Abstract
BK channels are potassium selective and exhibit large single-channel conductance. They play an important physiological role in glioma cells: they are involved in cell growth and extensive migrating behavior. Due to the fact that these processes are accompanied by changes in membrane stress, here, we examine mechanosensitive properties of BK channels from human glioblastoma cells (gBK channels). Experiments were performed by the use of patch-clamp method on excised patches under membrane suction (0-40 mmHg) at membrane hyper- and depolarization. We have also checked whether channel's activity is affected by possible changes of membrane morphology after a series of long impulses of suction. Unconventionally, we also analyzed internal structure of the experimental signal to make inferences about conformational dynamics of the channel in stressed membranes. We examined the fractal long-range memory effect (by R/S Hurst analysis), the rate of changes in information by sample entropy, or correlation dimension, and characterize its complexity over a range of scales by the use of Multiscale Entropy method. The obtained results indicate that gBK channels are mechanosensitive at membrane depolarization and hyperpolarization. Prolonged suction of membrane also influences open-closed fluctuations-it decreases channel's activity at membrane hyperpolarization and, in contrary, increases channel's activity at high voltages. Both membrane strain and its "fatigue" reduce dynamical complexity of channel gating, which suggest decrease in the number of available open conformations of channel protein in stressed membranes.
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Affiliation(s)
- Agata Wawrzkiewicz-Jałowiecka
- Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Gliwice, Poland.
| | - Paulina Trybek
- Division of Computational Physics and Electronics, Institute of Physics, Silesian Centre for Education and Interdisciplinary Research, University of Silesia in Katowice, Katowice, Poland
| | - Łukasz Machura
- Division of Computational Physics and Electronics, Institute of Physics, Silesian Centre for Education and Interdisciplinary Research, University of Silesia in Katowice, Katowice, Poland
| | - Beata Dworakowska
- Division of Biophysics, Department of Physics, Warsaw University of Life Sciences - SGGW, Warszawa, Poland
| | - Zbigniew J Grzywna
- Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Gliwice, Poland
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12
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Xin F, Cheng Y, Ren J, Zhang S, Liu P, Zhao H, Huang H, Wang W. The extracellular loop of the auxiliary β1-subunit is involved in the regulation of BKCa channel mechanosensitivity. Am J Physiol Cell Physiol 2018; 315:C485-C493. [DOI: 10.1152/ajpcell.00037.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The large conductance Ca2+-activated potassium (BKCa) channel is activated by stretch. The stress-regulated exon (STREX) in α-subunits is known to affect the mechanosensitivity of BKCa channels. However, in human colonic smooth muscle cells (HCoSMCs), we found that the α-subunits without STREX (ZERO-BK) and β1-subunits could be detected yet the cells were mechanosensitive. Whether the β1-subunit is involved in the regulation of BKCa mechanosensitivity is unclear. In the present study, ZERO-BK and β1-subunits were individually expressed or coexpressed in HEK293 cells and cell-attached patch-clamp techniques were used to measure BKCa currents defining mechanosensitivity. Single-channel patch-clamp recordings from HEK293 cells cotransfected with ZERO-BK and β1-subunits showed stretch sensitivity, but there was no mechanosensitivity in HEK293 cells transfected only with ZERO-BK. We also showed that expression of the β1-subunit could increase mechanosensitivity of the STREX-type α-subunits (STREX-BK). To identify the domain in β1-subunits responsible for affecting stretch sensitivity, we expressed β1- LoopDel (chimeric β1-subunits without the extracellular loop) or β1- C TermDel (chimeric β1-subunits without COOH terminus) with ZERO-BK in HEK293 cells. The data showed that deletion of the extracellular loop but not the COOH terminus of β1-subunits virtually abolished the mechanosensitivity. These results suggest that the extracellular loop of the β1-subunit is involved in the regulation of BKCa channel mechanosensitivity and that role is independent of STREX.
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Affiliation(s)
- Fang Xin
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
| | - Yuan Cheng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
| | - Jie Ren
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Diseases, Capital Medical University, Beijing, People’s Republic of China
| | - Sitao Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
| | - Ping Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
| | - Haiyan Zhao
- Yanjing Medical College, Capital Medical University, Beijing, People’s Republic of China
| | - Haixia Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
- Beijing Key Laboratory of Metabolic Disorders Related Cardiovascular Diseases, Capital Medical University, Beijing, People’s Republic of China
| | - Wei Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, People’s Republic of China
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13
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Suchyna TM. Piezo channels and GsMTx4: Two milestones in our understanding of excitatory mechanosensitive channels and their role in pathology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:244-253. [PMID: 28778608 DOI: 10.1016/j.pbiomolbio.2017.07.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/19/2022]
Abstract
Discovery of Piezo channels and the reporting of their sensitivity to the inhibitor GsMTx4 were important milestones in the study of non-selective cationic mechanosensitive channels (MSCs) in normal physiology and pathogenesis. GsMTx4 had been used for years to investigate the functional role of cationic MSCs, especially in muscle tissue, but with little understanding of its target or inhibitory mechanism. The sensitivity of Piezo channels to bilayer stress and its robust mechanosensitivity when expressed in heterologous systems were keys to determining GsMTx4's mechanism of action. However, questions remain regarding Piezo's role in muscle function due to the non-selective nature of GsMTx4 inhibition toward membrane mechanoenzymes and the implication of MCS channel types by genetic knockdown. Evidence supporting Piezo like activity, at least in the developmental stages of muscle, is presented. While the MSC targets of GsMTx4 in muscle pathology are unclear, its muscle protective effects are clearly demonstrated in two recent in situ studies on normal cardiomyocytes and dystrophic skeletal muscle. The muscle protective function may be due to the combined effect of GsMTx4's inhibitory action on cationic MSCs like Piezo and TRP, and its potentiation of repolarizing K+ selective MSCs like K2P and SAKCa. Paradoxically, the potent in vitro action of GsMTx4 on many physiological functions seems to conflict with its lack of in situ side-effects on normal animal physiology. Future investigations into cytoskeletal control of sarcolemma mechanics and the suspected inclusion of MSCs in membrane micro/nano sized domains with distinct mechanical properties will aide our understanding of this dichotomy.
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Affiliation(s)
- Thomas M Suchyna
- University of Buffalo, Dept. of Physiology and Biophysics, Buffalo, NY, USA.
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14
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Jin H, Iribe G, Naruse K. Effects of bepridil on stretch-activated BKca channels and stretch-induced extrasystoles in isolated chick hearts. Physiol Res 2017; 66:459-465. [PMID: 28248537 DOI: 10.33549/physiolres.933315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Various types of mechanosensitive ion channels, including cationic stretch-activated channels (SAC(NS)) and stretch-activated BKca (SAKca) channels, modulate heart rhythm. Bepridil has been used as an antiarrhythmic drug with multiple pharmacological effects; however, whether it is effective for mechanically induced arrhythmia has not been well investigated. To test the effects of Bepridil on SAKca channels activity, cultured chick embryonic ventricular myocytes were used for single-channel recordings. Bepridil significantly reduced the open probability of the SAKca channel (P(O)). Next, to test the effects of bepridil on stretch-induced extrasystoles (SIE), we used an isolated 2-week-old Langendorff-perfused chick heart. The left ventricle (LV) volume was rapidly changed, and the probability of SIE was calculated in the presence and absence of bepridil, and the effect of the drug was compared with that of Gadolinium (Gd(3+)). Bepridil decreased the probability of SIE despite its suppressive effects on SAKca channel activity. The effects of Gd(3+), which blocks both SAKca and SAC(NS), on the probability of SIE were the same as those of bepridil. Our results suggest that bepridil blocks not only SAKca channels but possible also blocks SAC(NS), and thus decreases the stretch-induced cation influx (stabilizing membrane potential) to compensate and override the effects of the decrease in outward SAKca current (destabilizing membrane potential).
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Affiliation(s)
- H Jin
- Department of Pharmacy, The Affiliated Hospital of YanBian University, YanJi City, JiLin Province, China. ; Cardiovascular Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Kita-ku, Okayama, Japan.
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15
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Hermann A, Sitdikova GF, Weiger TM. Oxidative Stress and Maxi Calcium-Activated Potassium (BK) Channels. Biomolecules 2015; 5:1870-911. [PMID: 26287261 PMCID: PMC4598779 DOI: 10.3390/biom5031870] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 01/13/2023] Open
Abstract
All cells contain ion channels in their outer (plasma) and inner (organelle) membranes. Ion channels, similar to other proteins, are targets of oxidative impact, which modulates ion fluxes across membranes. Subsequently, these ion currents affect electrical excitability, such as action potential discharge (in neurons, muscle, and receptor cells), alteration of the membrane resting potential, synaptic transmission, hormone secretion, muscle contraction or coordination of the cell cycle. In this chapter we summarize effects of oxidative stress and redox mechanisms on some ion channels, in particular on maxi calcium-activated potassium (BK) channels which play an outstanding role in a plethora of physiological and pathophysiological functions in almost all cells and tissues. We first elaborate on some general features of ion channel structure and function and then summarize effects of oxidative alterations of ion channels and their functional consequences.
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Affiliation(s)
- Anton Hermann
- Department of Cell Biology, Division of Cellular and Molecular Neurobiology, University of Salzburg, Salzburg 5020, Austria.
| | - Guzel F Sitdikova
- Department of Physiology of Man and Animals, Kazan Federal University, Kazan 420008, Russia.
| | - Thomas M Weiger
- Department of Cell Biology, Division of Cellular and Molecular Neurobiology, University of Salzburg, Salzburg 5020, Austria.
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16
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Lai MH, Wu Y, Gao Z, Anderson ME, Dalziel JE, Meredith AL. BK channels regulate sinoatrial node firing rate and cardiac pacing in vivo. Am J Physiol Heart Circ Physiol 2014; 307:H1327-38. [PMID: 25172903 DOI: 10.1152/ajpheart.00354.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Large-conductance Ca(2+)- and voltage-activated K(+) (BK) channels play prominent roles in shaping muscle and neuronal excitability. In the cardiovascular system, BK channels promote vascular relaxation and protect against ischemic injury. Recently, inhibition of BK channels has been shown to lower heart rate in intact rodents and isolated hearts, suggesting a novel role in heart function. However, the underlying mechanism is unclear. In the present study, we recorded ECGs from mice injected with paxilline (PAX), a membrane-permeable BK channel antagonist, and examined changes in cardiac conduction. ECGs revealed a 19 ± 4% PAX-induced reduction in heart rate in wild-type but not BK channel knockout (Kcnma1(-/-)) mice. The heart rate decrease was associated with slowed cardiac pacing due to elongation of the sinus interval. Action potential firing recorded from isolated sinoatrial node cells (SANCs) was reduced by 55 ± 15% and 28 ± 9% by application of PAX (3 μM) and iberiotoxin (230 nM), respectively. Furthermore, baseline firing rates from Kcnma1(-/-) SANCs were 33% lower than wild-type SANCs. The slowed firing upon BK current inhibition or genetic deletion was due to lengthening of the diastolic depolarization phase of the SANC action potential. Finally, BK channel immunoreactivity and PAX-sensitive currents were identified in SANCs with HCN4 expression and pacemaker current, respectively, and BK channels cloned from SANCs recapitulated similar activation as the PAX-sensitive current. Together, these data localize BK channels to SANCs and demonstrate that loss of BK current decreases SANC automaticity, consistent with slowed sinus pacing after PAX injection in vivo. Furthermore, these findings suggest BK channels are potential therapeutic targets for disorders of heart rate.
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Affiliation(s)
- Michael H Lai
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Yuejin Wu
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Zhan Gao
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
| | - Mark E Anderson
- Department of Internal Medicine and the François M. Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa; Department of Physiology and Molecular Biophysics, University of Iowa, Iowa City, Iowa; and
| | - Julie E Dalziel
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland; Fischell Department of Bioengineering, University of Maryland, College Park, Maryland;
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17
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Takahashi K, Naruse K. Stretch-activated BK channel and heart function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 110:239-44. [PMID: 23281538 DOI: 10.1016/j.pbiomolbio.2012.08.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The heart is an organ that is exposed to extreme dynamic mechanical stimuli. From birth till death, the heart indefinitely repeats periodic contraction and dilation, i.e., shortening and elongation of cardiomyocytes. Mechanical stretch elicits a change in heart rate and may cause arrhythmia if it is excessive. Thus, mechanosensitivity is crucial to heart function. The molecule that is substantially involved in mechanosensitivity is a stretch-activated ion channel. Among several ion channels believed to be activated by stretch in the heart, the stretch-activated KCa (SAKCA) channel, a member of the group of large conductance (Big Potassium, BK) channels, shows a mechanosensitive (MS) response to membrane stretch. As BK channels respond to voltage and intracellular calcium concentration with large conductance, they are considered to be involved in repolarization after depolarization. Some BK channels are known to be activated by stretch and are expressed in a number of cells, including human osteoblasts and guinea pig intestinal neurons. The SAKCA channel was found to be sensitive to stretch in the chick heart. Given that the cardiomyocyte is unremittingly exposed to contraction and dilation and that it generates action potential and its contractility is modulated by intracellular calcium concentration, the SAKCA channel, which is dependent voltage and calcium, may be involved in action potential generation. It was recently reported that a BK channel is involved in the modulation of heart rate in the mouse. Further studies regarding the role of MS BK channels, including SAKCA, in the modulation of heart rate and contractility are expected.
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Affiliation(s)
- Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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18
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Li N, Shi Y, Shi L, Liu Y, Zhang Y. Effects of aerobic exercise training on large-conductance Ca2+-activated K+ channels in rat cerebral artery smooth muscle cells. Eur J Appl Physiol 2013; 113:2553-63. [DOI: 10.1007/s00421-013-2695-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 07/05/2013] [Indexed: 01/23/2023]
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19
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Takahashi K, Kakimoto Y, Toda K, Naruse K. Mechanobiology in cardiac physiology and diseases. J Cell Mol Med 2013; 17:225-32. [PMID: 23441631 PMCID: PMC3822585 DOI: 10.1111/jcmm.12027] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Accepted: 01/11/2013] [Indexed: 11/28/2022] Open
Abstract
Mechanosensitivity is essential for heart function just as for all other cells and organs in the body, and it is involved in both normal physiology and diseases processes of the cardiovascular system. In this review, we have outlined the relationship between mechanosensitivity and heart physiology, including the Frank-Starling law of the heart and mechanoelectric feedback. We then focused on molecules involved in mechanotransduction, particularly mechanosensitive ion channels. We have also discussed the involvement of mechanosensitivity in heart diseases, such as arrhythmias, hypertrophy and ischaemic heart disease. Finally, mechanobiology in cardiogenesis is described with regard to regenerative medicine.
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Affiliation(s)
- Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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20
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Shi L, Liu B, Li N, Xue Z, Liu X. Aerobic exercise increases BK(Ca) channel contribution to regulation of mesenteric arterial tone by upregulating β1-subunit. Exp Physiol 2012; 98:326-36. [PMID: 22660813 DOI: 10.1113/expphysiol.2012.066225] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Substantial evidence has shown that exercise training produces numerous adaptations within the arteries. Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels are expressed broadly on smooth muscle cells and play an important role in the regulation of vascular tone. The present study was designed to investigate the mechanisms by which the BK(Ca) channel underlies the exercise-induced improvement of the vascular function in mesenteric arteries. Male Wistar rats (180-200 g) were trained for 12 weeks on a treadmill (EX group) and compared with age-matched sedentary (SED) animals. Blood pressure and vascular contractility of mesenteric arteries were measured. Inside-out patch-clamp recording was applied on the freshly separated mesenteric smooth muscle cells to investigate the gating characteristics of BK(Ca) channels. Western immunoblotting was performed to study expression levels of BK(Ca) channel proteins. The maximal vascular contraction induced by noradrenaline (3 × 10(-5) M) was decreased after exercise training. Both TEA (3 × 10(-3) M) and iberiotoxin (3 × 10(-8) M) induced a significant increase of vessel tension in both SED and EX groups, but these effects were more pronounced in EX rats compared with SED animals. Inside-out patch-clamp recording showed that exercise training significantly increased the open probability, decreased the mean closed time and increased the mean open time and the sensitivity to Ca(2+) and voltage without altering the unitary conductance. The expression of BK(Ca) β1- but not α-subunit was significantly enhanced after exercise training. These data suggest that exercise training increases the contribution of the BK(Ca) channel to the regulation of vascular tone in mesenteric arteries, which is possibly mediated by upregulating β1-subunit protein to increase BK(Ca) channel activity.
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Affiliation(s)
- Lijun Shi
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, PR China.
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21
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Wang W, Huang H, Hou D, Liu P, Wei H, Fu X, Niu W. Mechanosensitivity of STREX-lacking BKCa channels in the colonic smooth muscle of the mouse. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1231-40. [PMID: 20864656 DOI: 10.1152/ajpgi.00268.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Stretch sensitivity of Ca²(+)-activated large-conductance K(+) channels (BK(Ca)) has been observed in a variety of cell types and considered to be a potential mechanism in mechanoelectric transduction (MET). Mechanical stress is a major stimulator for the smooth muscle in the gastrointestinal (GI) tract. However, much about the role and mechanism of MET in GI smooth muscles remains unknown. The BK(Ca) shows a functional diversity due to intensive Slo I alternative splicing and different α/β-subunit assembly in various cells. The stress-regulated exon (STREX) insert is suggested to be an indispensable domain for the mechanosensitivity of BK(Ca). The purpose of this study was to determine whether the BK(Ca) in colonic myocytes of the adult mouse is sensitive to mechanical stimulation and whether the STREX insert is a crucial segment for the BK(Ca) mechanosensitivity. The α- and β1-subunit mRNAs and the α-subunit protein of the BK(Ca) channels were detected in the colonic muscularis. We found that the BK(Ca) STREX-lacking variant was abundantly expressed in the smooth muscle, whereas the STREX variant was not detectable. We demonstrated that the STREX-lacking BK(Ca) channels were also sensitive to membrane stretch. We suggest that in addition to the STREX domain, there are other additional structures in the channel responsible for mechanically coupling with the cell membrane.
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Affiliation(s)
- Wei Wang
- Dept. of Physiology, Capital Medical Univ., Beijing, PR China
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22
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Zhao HC, Agula H, Zhang W, Wang F, Sokabe M, Li LM. Membrane stretch and cytoplasmic Ca2+ independently modulate stretch-activated BK channel activity. J Biomech 2010; 43:3015-9. [DOI: 10.1016/j.jbiomech.2010.06.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 06/28/2010] [Accepted: 06/30/2010] [Indexed: 12/23/2022]
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23
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Araki I, Yoshiyama M, Kobayashi H, Mochizuki T, Du S, Okada Y, Takeda M. Emerging Families of Ion Channels Involved in Urinary Bladder Nociception. Pharmaceuticals (Basel) 2010; 3:2248-2267. [PMID: 27713353 PMCID: PMC4036652 DOI: 10.3390/ph3072248] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 06/28/2010] [Accepted: 07/15/2010] [Indexed: 01/12/2023] Open
Abstract
The expression of multiple ion channels and receptors is essential for nociceptors to detect noxious stimuli of a thermal, mechanical or chemical nature. The peripheral sensory transduction systems of the urinary bladder include sensory nerve endings, urothelial cells and others whose location is suitable for transducing mechanical and chemical stimuli. There is an increasing body of evidence implicating the Deg/ENaC and TRP channel families in the control of bladder afferent excitability under physiological and pathological conditions. Pharmacological interventions targeting these ion channels may provide a new strategy for the treatment of pathological bladder sensation and pain.
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Affiliation(s)
- Isao Araki
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Yamanashi 409-3898, Japan.
- Department of Urology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan.
| | - Mitsuharu Yoshiyama
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Yamanashi 409-3898, Japan.
| | - Hideki Kobayashi
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Yamanashi 409-3898, Japan.
| | - Tsutomu Mochizuki
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Yamanashi 409-3898, Japan.
| | - Shuqi Du
- Department of Urology, the 1st Affiliated Hospital, China Medical University, Shenyang, China.
| | - Yusaku Okada
- Department of Urology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan.
| | - Masayuki Takeda
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Yamanashi 409-3898, Japan.
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24
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Tang QY, Zhang Z, Xia J, Ren D, Logothetis DE. Phosphatidylinositol 4,5-bisphosphate activates Slo3 currents and its hydrolysis underlies the epidermal growth factor-induced current inhibition. J Biol Chem 2010; 285:19259-66. [PMID: 20392696 PMCID: PMC2885204 DOI: 10.1074/jbc.m109.100156] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 03/20/2010] [Indexed: 11/06/2022] Open
Abstract
The Slo3 gene encodes a high conductance potassium channel, which is activated by both voltage and intracellular alkalinization. Slo3 is specifically expressed in mammalian sperm cells, where it gives rise to pH-dependent outwardly rectifying K(+) currents. Sperm Slo3 is the main current responsible for the capacitation-induced hyperpolarization, which is required for the ensuing acrosome reaction, an exocytotic process essential for fertilization. Here we show that in intact spermatozoa and in a heterologous expression system, the activation of Slo3 currents is regulated by phosphatidylinositol 4,5-bisphosphate (PIP(2)). Depletion of endogenous PIP(2) in inside-out macropatches from Xenopus oocytes inhibited heterologously expressed Slo3 currents. Whole-cell recordings of sperm Slo3 currents or of Slo3 channels co-expressed in Xenopus oocytes with epidermal growth factor receptor, demonstrated that stimulation by epidermal growth factor (EGF) could inhibit channel activity in a PIP(2)-dependent manner. High concentrations of PIP(2) in the patch pipette not only resulted in a strong increase in sperm Slo3 current density but also prevented the EGF-induced inhibition of this current. Mutation of positively charged residues involved in channel-PIP(2) interactions enhanced the EGF-induced inhibition of Slo3 currents. Overall, our results suggest that PIP(2) is an important regulator for Slo3 activation and that receptor-mediated hydrolysis of PIP(2) leads to inhibition of Slo3 currents both in native and heterologous expression systems.
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Affiliation(s)
- Qiong-Yao Tang
- From the Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298-0551 and
| | - Zhe Zhang
- From the Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298-0551 and
| | - Jingsheng Xia
- the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Dejian Ren
- the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Diomedes E. Logothetis
- From the Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298-0551 and
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25
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Iribe G, Jin H, Kaihara K, Naruse K. Effects of axial stretch on sarcolemmal BKCachannels in post-hatch chick ventricular myocytes. Exp Physiol 2010; 95:699-711. [DOI: 10.1113/expphysiol.2009.051896] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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26
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Kirkham G, Elliot K, Keramane A, Salter D, Dobson J, El Haj A, Cartmell S. Hyperpolarization of Human Mesenchymal Stem Cells in Response to Magnetic Force. IEEE Trans Nanobioscience 2010; 9:71-4. [DOI: 10.1109/tnb.2010.2042065] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Naruse K, Tang QY, Sokabe M. Stress-Axis Regulated Exon (STREX) in the C terminus of BKCa channels is responsible for the stretch sensitivity. Biochem Biophys Res Commun 2009; 385:634-9. [DOI: 10.1016/j.bbrc.2009.05.105] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 05/25/2009] [Indexed: 12/30/2022]
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28
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Differential expression of BK channel isoforms and β-subunits in rat neuro-vascular tissues. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:380-9. [DOI: 10.1016/j.bbamem.2008.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 09/18/2008] [Accepted: 10/06/2008] [Indexed: 12/30/2022]
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29
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Kim EY, Alvarez-Baron CP, Dryer SE. Canonical transient receptor potential channel (TRPC)3 and TRPC6 associate with large-conductance Ca2+-activated K+ (BKCa) channels: role in BKCa trafficking to the surface of cultured podocytes. Mol Pharmacol 2008; 75:466-77. [PMID: 19052171 DOI: 10.1124/mol.108.051912] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Large-conductance (BK(Ca) type) Ca(2+)-activated K(+) channels encoded by the Slo1 gene and various canonical transient receptor potential channels (TRPCs) are coexpressed in many cell types, including podocytes (visceral epithelial cells) of the renal glomerulus. In this study, we show by coimmunoprecipitation and GST pull-down assays that BK(Ca) channels can associate with endogenous TRPC3 and TRPC6 channels in differentiated cells of a podocyte cell line. Both types of TRPC channels colocalize with Slo1 in podocytes and in human embryonic kidney (HEK) 293T cells transiently coexpressing the TRPC channels with Slo1. In HEK293T cells, coexpression of TRPC6 increased surface expression of a Slo1 subunit splice variant (Slo1(VEDEC)) that is typically retained in intracellular compartments, as assessed by cell-surface biotinylation assays and confocal microscopy. Corresponding currents through BK(Ca) channels were also increased with TRPC6 coexpression, as assessed by whole-cell and excised inside-out patch recordings. By contrast, coexpression of TRPC3 had no effect on the surface expression of BK(Ca) channels in HEK293T cells or on the amplitudes of currents in whole cells or excised patches. In podocytes, small interfering RNA knockdown of endogenous TRPC6 reduced steady-state surface expression of endogenous Slo1 channels, but knockdown of TRPC3 had no effect. TRPC6, but not TRPC3 knockdown also reduced voltage-evoked outward current through podocyte BK(Ca) channels. These data indicate that TRPC6 and TRPC3 channels can bind to Slo1, and this colocalization may allow them to serve as a source of Ca(2+) for the activation of BK(Ca) channels. TRPC6 channels also play a role in the regulation of surface expression of a subset of podocyte BK(Ca) channels.
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Affiliation(s)
- Eun Young Kim
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
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30
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Zhao H, Sokabe M. Tuning the mechanosensitivity of a BK channel by changing the linker length. Cell Res 2008; 18:871-8. [DOI: 10.1038/cr.2008.88] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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31
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Araki I, Du S, Kobayashi H, Sawada N, Mochizuki T, Zakoji H, Takeda M. Roles of mechanosensitive ion channels in bladder sensory transduction and overactive bladder. Int J Urol 2008; 15:681-7. [PMID: 18462357 DOI: 10.1111/j.1442-2042.2008.02052.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In the storage phase, mechanical stretch stimulates bladder afferents. These signals generate sensations and trigger voiding responses, however the precise mechanisms by which mechanical stimuli excite bladder afferents are yet to be explored. For mechanosensory transduction, the presence of mechanosensors is essential in the peripheral sensory systems including sensory nerve endings, urothelium and others. There is increasing evidence that mechanosensitive ion channels, such as degenerin/epithelial Na(+) channel (ENaC) and transient receptor potential (TRP) channel families, play key roles in the mechanosensory transduction of the urinary bladder. Pharmacological interventions targeting mechanosensitive ion channels may provide a new strategy for the treatment of bladder dysfunction.
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Affiliation(s)
- Isao Araki
- Department of Urology, University of Yamanashi Interdisciplinary Graduate School of Medicine and Engineering, Chuo, Japan.
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32
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Tran TA, Le Guennec JY, Bougnoux P, Tranquart F, Bouakaz A. Characterization of cell membrane response to ultrasound activated microbubbles. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:43-49. [PMID: 18334312 DOI: 10.1109/tuffc.2008.615] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Contrast agents for ultrasound imaging, composed of tiny gas microbubbles, have become a reality in clinical routine. They are extensively used in radiology for detection and characterization of various tumors and in cardiology for left ventricular opacification. Recent experimental studies showed that ultrasound waves in combination with contrast agent microbubbles increase transiently cell membrane permeability in a process known as sonoporation. This effect is thought to allow foreign molecules to enter the cell. In that context, we explored the cell membrane's responses to microbubbles' oscillations as the mechanism is not completely understood. Breast cancer cell line in combination with contrast microbubbles were used. Ultrasound was applied using a transducer of 1 MHz center frequency transmitting a 10-cycle burst of different acoustic pressures repeated every 100 mus. Patch-clamp technique in whole cell configuration was used to explore transmembrane ion exchange through the variations in membrane potential. To characterize the activated ion channels, the variations of the intracellular calcium (Ca(2+)) concentration were explored using a fluorescent marker. The results revealed that ultrasound stimulation induces a rapid hyperpolarization of cell membrane potential when the microbubble is in direct contact with the cell, but the potential returned to its initial value when ultrasound stimulation stopped. The change in cell membrane potential indicates the activation of specific ion channels and depends on the quality of microbubble adhesion to the cell membrane. Microbubbles were shown to induce a mechanical stretch activating BKca channels. Simultaneous Ca(2+) measurements indicate a slow and progressive Ca(2+) increase that is likely a consequence of BKca channels opening not a cause. These results demonstrate that microbubbles' oscillations under ultrasound activation entail modulation of cellular function and signaling by t- riggering the modulation of ionic transports through the cell membrane. Cells response to the mechanical stretch caused by gentle microbubble oscillations is characterized by the opening of BKca stretch channels and a Ca(2+) flux, which might potentially trigger other cellular responses responsible for membrane sonopermeabilization.
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33
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Gottlieb PA, Suchyna TM, Sachs F. Properties and Mechanism of the Mechanosensitive Ion Channel Inhibitor GsMTx4, a Therapeutic Peptide Derived from Tarantula Venom. CURRENT TOPICS IN MEMBRANES 2007; 59:81-109. [PMID: 25168134 DOI: 10.1016/s1063-5823(06)59004-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Mechanosensitive ion channels (MSCs) are found in all types of cells ranging from Escherichia coli to morning glories to humans. They seem to fall into two families: those in specialized receptors, such as the hair cells of the cochlea, and those in cells not clearly differentiated for sensory duty. The physiological function of the channels in nonspecialized cells has not been demonstrated, although their activity has been demonstrated innumerable times in vitro. The only specific reagent to block MSCs isGsMTx4, a 4-kDa peptide isolated from tarantula venom. Despite being isolated from venom, it is nontoxic to mice. GsMTx4 is specific for an MSC subtype, the nonselective cation channels that may be members of the transient receptor potential (TRP) family. GsMTx4 acts as a gating modifier, increasing the energy of the open state relative to the closed state. The mirror image D enantiomer of GsMTx4 is equally active, so mode of action is not via the traditional lock and key model. GsMTx4 probably acts in the boundary lipid of the channel by changing local curvature and mechanically stressing the channel toward the closed state. Despite the lack of definitive physiological data on the function of the cationic MSCs, GsMTx4 may prove useful as a drug or lead compound that can affect physiological processes. These processes would be those driven by mechanical stress, such as blood vessel autoregulation, stress-induced contraction of smooth muscle, and Ca(2+) loading in muscular dystrophy.
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Affiliation(s)
- Philip A Gottlieb
- The Department of Physiology and Biophysics, Center for Single Molecule Biophysics, SUNY at Buffalo, Buffalo, New York 14214
| | - Thomas M Suchyna
- The Department of Physiology and Biophysics, Center for Single Molecule Biophysics, SUNY at Buffalo, Buffalo, New York 14214
| | - Frederick Sachs
- The Department of Physiology and Biophysics, Center for Single Molecule Biophysics, SUNY at Buffalo, Buffalo, New York 14214
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34
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Bowman CL, Gottlieb PA, Suchyna TM, Murphy YK, Sachs F. Mechanosensitive ion channels and the peptide inhibitor GsMTx-4: history, properties, mechanisms and pharmacology. Toxicon 2007; 49:249-70. [PMID: 17157345 PMCID: PMC1852511 DOI: 10.1016/j.toxicon.2006.09.030] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Sensing the energy from mechanical inputs is ubiquitous--and perhaps the oldest form of biological energy transduction. However, the tools available to probe the mechanisms of transduction are far fewer than for the chemical and electric field sensitive transducers. The one pharmacological tool available for mechansensitive ion channels (MSCs) is a peptide (GsMTx-4) isolated from venom of the tarantula, Grammostola spatulata, that blocks cationic MSCs found in non-specialized eukaryotic tissues. In this review, we summarize the current knowledge of GsMTx-4, and discuss the inevitable crosstalk between the MSC behavior and the mechanical properties of the cell cortex.
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Affiliation(s)
- Charles L Bowman
- Center for Single Molecule Biophysics and The Department of Physiology and Biophysics, SUNY at Buffalo, Buffalo, NY 14214, USA.
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35
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Matthews BD, Thodeti CK, Ingber DE. Activation of Mechanosensitive Ion Channels by Forces Transmitted Through Integrins and the Cytoskeleton. MECHANOSENSITIVE ION CHANNELS, PART A 2007. [DOI: 10.1016/s1063-5823(06)58003-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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36
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Hamill OP. Twenty odd years of stretch-sensitive channels. Pflugers Arch 2006; 453:333-51. [PMID: 17021800 DOI: 10.1007/s00424-006-0131-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 06/27/2006] [Indexed: 01/15/2023]
Abstract
After formation of the giga-seal, the membrane patch can be stimulated by hydrostatic or osmotic pressure gradients applied across the patch. This feature led to the discovery of stretch-sensitive or mechanosensitive (MS) channels, which are now known to be ubiquitously expressed in cells representative of all the living kingdoms. In addition to mechanosensation, MS channels have been implicated in many basic cell functions, including regulation of cell volume, shape, and motility. The successful cloning, overexpression, and crystallization of bacterial MS channel proteins combined with patch clamp and modeling studies have provided atomic insight into the working of these nanomachines. In particular, studies of MS channels have revealed new understanding of how the lipid bilayer modulates membrane protein function. Three major membrane protein families, transient receptor potential, 2 pore domain K(+), and the epithelial Na(+) channels, have been shown to form MS channels in animal cells, and their polymodal activation embrace fields far beyond mechanosensitivity. The discovery of new drugs highly selective for MS channels ("mechanopharmaceutics") and the demonstration of MS channel involvement in several major human diseases ("mechanochannelopathies") provide added motivation for devising new techniques and approaches for studying MS channels.
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Affiliation(s)
- O P Hamill
- Neurosciences and Cell Biology, UTMB, Galveston, TX, 77555, USA.
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37
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Dejean LM, Martinez-Caballero S, Kinnally KW. Is MAC the knife that cuts cytochrome c from mitochondria during apoptosis? Cell Death Differ 2006; 13:1387-95. [PMID: 16676005 DOI: 10.1038/sj.cdd.4401949] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Apoptosis is a phenomenon fundamental to higher eukaryotes and essential to mechanisms controlling tissue homeostasis. Bcl-2 family proteins tightly control this cell death program by regulating the permeabilization of the mitochondrial outer membrane and, hence, the release of cytochrome c and other proapoptotic factors. Mitochondrial apoptosis-induced channel (MAC) is the mitochondrial apoptosis-induced channel and is responsible for cytochrome c release early in apoptosis. MAC activity is detected by patch clamping mitochondria at the time of cytochrome c release. The Bcl-2 family proteins regulate apoptosis by controlling the formation of MAC. Depending on cell type and apoptotic inducer, Bax and/or Bak are structural component(s) of MAC. Overexpression of the antiapoptotic protein Bcl-2 eliminates MAC activity. The focus of this review is a biophysical characterization of MAC activity and its regulation by Bcl-2 family proteins, and ends with some discussion of therapeutic targets.
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Affiliation(s)
- L M Dejean
- Department of Basic Sciences, College of Dentistry, New York University, NY 10010, USA
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38
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Qi Z, Chi S, Su X, Naruse K, Sokabe M. Activation of a mechanosensitive BK channel by membrane stress created with amphipaths. Mol Membr Biol 2006; 22:519-27. [PMID: 16373323 DOI: 10.1080/09687860500370703] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Some BK channels are activated in response to membrane stretch. However, it remains largely unknown which membrane component transmits forces to the channel and which part of the channel senses the force. Recently, we have shown that a BK channel cloned from chick heart (named SAKCa channel) is a stretch activated channel, while deletion of a 59 amino acids splice insert (STREX) located in the cytoplasmic side, abolishes its stretch-sensitivity. This finding raised a question whether stress in the bilayer is crucial for the mechanical activation of the channel. To address this question we examined the effects of membrane perturbing amphipaths on the stretch activation of the SAKCa channel and its STREX-deletion mutant. We found that both anionic amphipath trinitrophenol (TNP) and cationic amphipath chlorpromazine (CPZ) could dose-dependently activate the channel by leftward shifting the voltage activation curve when applied alone. In contrast, TNP and CPZ compensated each other's effect when applied sequentially. These results can be understood in the framework of the bilayer couple hypothesis, suggesting that stress in the plasma membrane can activate the SAKCa channel. Interestingly, the STREX-deletion mutant channel has much less sensitivity to the amphipaths, suggesting that STREX acts as an intermediate structure that can indirectly convey stress in the membrane to the gate of the SAKCa channel via an unidentified membrane associated protein(s) that can detect or transmit stress in the membrane.
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Affiliation(s)
- Zhi Qi
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, 15 Datun Rd, Beijing, 100101, PR China
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39
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Qi Z, Kishigami A, Nakagawa Y, Iida H, Sokabe M. A mechanosensitive anion channel in Arabidopsis thaliana mesophyll cells. PLANT & CELL PHYSIOLOGY 2004; 45:1704-1708. [PMID: 15574846 DOI: 10.1093/pcp/pch194] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mechanosensitive ion channels are expected to play important roles in transducing mechanical stimuli into intracellular signals during the development and morphogenesis of higher plants. We have identified a novel mechanosensitive anion channel in the protoplast of Arabidopsis thaliana mesophyll cells by using the patch-clamp technique. The channel in the outside-out patches could be activated by positive pressure in the pipette while negative pressure had no effect. The amphipathic membrane crenator trinitrophenol, which is supposed to preferentially insert in the outer leaflet of the lipid bilayer of the plasma membrane, synergized with mechanical membrane stretch to activate the channel. These results suggest that the channel activation is mediated by a convex curvature of the plasma membrane. Therefore, activation of this channel may play an important role when cell volume is increasing during cell growth or hypo-osmotic challenge, which is accompanied by membrane stretch with increasingly convex curvature.
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Affiliation(s)
- Zhi Qi
- Lab of Visual Information Processing, Centre for Brain and Cognitive Sciences, Institute of Biophysics, CAS, 15 Da Tun Road, Chaoyang District, Beijing 100101, China.
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40
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Sokabe M, Naruse K, Qiong-Yao T. [A new mechanosensitive channel SAKCA and a new MS channel blocker GsTMx-4]. Nihon Yakurigaku Zasshi 2004; 124:301-10. [PMID: 15502395 DOI: 10.1254/fpj.124.301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Cells can respond to a variety of mechanical stimuli such as tension, pressure, and shear stress. However, the mechanisms of mechanotransduction are largely unknown. The major reason for this lies in the ambiguity of the molecular entity of cell mechanosensors. Currently only MS (mechanosensitive) channels conform to an established class of mechanosensors due to the firm and detailed analyses by electrophysiolgy. Although molecular structures of MS channels are known for limited members, higher order structures of bacterial MS channels have been resolved and their detailed structure-function studies are in progress. In contrast, molecular and biophysical analyses of eukaryote MS channels, which may attract much attention, are yet not well-studied. Although many candidate molecules have been proposed as the cell mechanosensor, currently only 2-pore-domain K channels (TREK/TRAAK) and SAKCA, a new class of MS channel introduced here, may be the subjects eligible for rigorous electrophysiological analyses. On the other hand, lack of specific blockers to MS channels is another reason why the progress in this field is slow. Gadolinium (Gd(3+)) has been extensively used as a potent blocker of MS channels, but its nonspecific actions have limited its usefulness. Very recently, a promising 35 mer peptide, which can be more specific for MS channels, named GsMTx-4 has been isolated from spider venom. This peptide is interesting because it inhibits stretch-induced atrial fibrillation, which may involve MS channel activation and thus can be used as a basis for developing a new class of drugs to cure heart failure. This short review deals with recent progresses in MS channel studies and the structure-function of SAKCA, a recently cloned MS channel from heart, as well as its interaction with the new MS channel blocker GsMTx-4.
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Affiliation(s)
- Masahiro Sokabe
- Department of Physiology, Nagoya University Graduate School of Medicine
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41
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Abstract
Mechanosensitive ion channels are the primary transducers that convert mechanical force into an electrical or chemical signal in hearing, touch, and other mechanical senses. Unlike vision, olfaction, and some types of taste, which all use similar kinds of primary heterotrimeric GTP-binding protein-coupled receptors, mechanosensation relies on diverse types of transducer molecules. Unrelated types of channels can be used for the perception of various mechanical stimuli, not only in distant groups of organisms, but also in separate locations of the same organism. The extreme sensitivity of the transduction mechanism in the auditory system, which relies on an elaborate structure of rigid cilia, filamentous links, and molecular motors to focus force on transduction channels, contrasts with that of the bacterial channel MscL, which is opened by high lateral tension in the membrane and fulfills a safety-valve rather than a sensory function. The spatial scales of conformational movement and force in these two systems are described, and are shown to be consistent with a general physical description of mechanical channel gating. We outline the characteristics of several types of mechanosensitive channels and the functional contexts in which they participate in signaling and cellular regulation in sensory and nonsensory cells.
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Affiliation(s)
- Sergei Sukharev
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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