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Saito T, Suzuki M, Ohba A, Hamaguchi S, Namekata I, Tanaka H. Enhanced Late I Na Induces Intracellular Ion Disturbances and Automatic Activity in the Guinea Pig Pulmonary Vein Cardiomyocytes. Int J Mol Sci 2024; 25:8688. [PMID: 39201376 PMCID: PMC11354854 DOI: 10.3390/ijms25168688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 07/30/2024] [Accepted: 08/07/2024] [Indexed: 09/02/2024] Open
Abstract
The effects of enhanced late INa, a persistent component of the Na+ channel current, on the intracellular ion dynamics and the automaticity of the pulmonary vein cardiomyocytes were studied with fluorescent microscopy. Anemonia viridis toxin II (ATX- II), an enhancer of late INa, caused increases in the basal Na+ and Ca2+ concentrations, increases in the number of Ca2+ sparks and Ca2+ waves, and the generation of repetitive Ca2+ transients. These phenomena were inhibited by eleclazine, a blocker of the late INa; SEA0400, an inhibitor of the Na+/Ca2+ exchanger (NCX); H89, a protein kinase A (PKA) inhibitor; and KN-93, a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor. These results suggest that enhancement of late INa in the pulmonary vein cardiomyocytes causes disturbance of the intracellular ion environment through activation of the NCX and Ca2+-dependent enzymes. Such mechanisms are probably involved in the ectopic electrical activity of the pulmonary vein myocardium.
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Affiliation(s)
| | | | | | | | - Iyuki Namekata
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama Funabashi, Chiba 274-8510, Japan; (T.S.); (M.S.); (A.O.); (S.H.); (H.T.)
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2
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Xue J, Zeng W, Han Y, John S, Ottolia M, Jiang Y. Structural mechanisms of the human cardiac sodium-calcium exchanger NCX1. Nat Commun 2023; 14:6181. [PMID: 37794011 PMCID: PMC10550945 DOI: 10.1038/s41467-023-41885-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/22/2023] [Indexed: 10/06/2023] Open
Abstract
Na+/Ca2+ exchangers (NCX) transport Ca2+ in or out of cells in exchange for Na+. They are ubiquitously expressed and play an essential role in maintaining cytosolic Ca2+ homeostasis. Although extensively studied, little is known about the global structural arrangement of eukaryotic NCXs and the structural mechanisms underlying their regulation by various cellular cues including cytosolic Na+ and Ca2+. Here we present the cryo-EM structures of human cardiac NCX1 in both inactivated and activated states, elucidating key structural elements important for NCX ion exchange function and its modulation by cytosolic Ca2+ and Na+. We demonstrate that the interactions between the ion-transporting transmembrane (TM) domain and the cytosolic regulatory domain define the activity of NCX. In the inward-facing state with low cytosolic [Ca2+], a TM-associated four-stranded β-hub mediates a tight packing between the TM and cytosolic domains, resulting in the formation of a stable inactivation assembly that blocks the TM movement required for ion exchange function. Ca2+ binding to the cytosolic second Ca2+-binding domain (CBD2) disrupts this inactivation assembly which releases its constraint on the TM domain, yielding an active exchanger. Thus, the current NCX1 structures provide an essential framework for the mechanistic understanding of the ion transport and cellular regulation of NCX family proteins.
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Affiliation(s)
- Jing Xue
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Weizhong Zeng
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yan Han
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Scott John
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Michela Ottolia
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Youxing Jiang
- Howard Hughes Medical Institute and Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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3
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Marchiano S, Nakamura K, Reinecke H, Neidig L, Lai M, Kadota S, Perbellini F, Yang X, Klaiman JM, Blakely LP, Karbassi E, Fields PA, Fenix AM, Beussman KM, Jayabalu A, Kalucki FA, Potter JC, Futakuchi-Tsuchida A, Weber GJ, Dupras S, Tsuchida H, Pabon L, Wang L, Knollmann BC, Kattman S, Thies RS, Sniadecki N, MacLellan WR, Bertero A, Murry CE. Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy. Cell Stem Cell 2023; 30:396-414.e9. [PMID: 37028405 PMCID: PMC10283080 DOI: 10.1016/j.stem.2023.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/03/2023] [Accepted: 03/16/2023] [Indexed: 04/08/2023]
Abstract
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) offer a promising cell-based therapy for myocardial infarction. However, the presence of transitory ventricular arrhythmias, termed engraftment arrhythmias (EAs), hampers clinical applications. We hypothesized that EA results from pacemaker-like activity of hPSC-CMs associated with their developmental immaturity. We characterized ion channel expression patterns during maturation of transplanted hPSC-CMs and used pharmacology and genome editing to identify those responsible for automaticity in vitro. Multiple engineered cell lines were then transplanted in vivo into uninjured porcine hearts. Abolishing depolarization-associated genes HCN4, CACNA1H, and SLC8A1, along with overexpressing hyperpolarization-associated KCNJ2, creates hPSC-CMs that lack automaticity but contract when externally stimulated. When transplanted in vivo, these cells engrafted and coupled electromechanically with host cardiomyocytes without causing sustained EAs. This study supports the hypothesis that the immature electrophysiological prolife of hPSC-CMs mechanistically underlies EA. Thus, targeting automaticity should improve the safety profile of hPSC-CMs for cardiac remuscularization.
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Affiliation(s)
- Silvia Marchiano
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kenta Nakamura
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Hans Reinecke
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Lauren Neidig
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA
| | | | - Shin Kadota
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Regenerative Science and Medicine, Shinshu University, Matsumoto 390-8621, Japan
| | | | - Xiulan Yang
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jordan M Klaiman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Leslie P Blakely
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Elaheh Karbassi
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Paul A Fields
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Adaptive Biotechnologies, Seattle, WA 98102, USA
| | - Aidan M Fenix
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kevin M Beussman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Mechanical Engineering, University of Washington, 3720 15(th) Avenue NE, Seattle, WA 98105, USA
| | - Anu Jayabalu
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Faith A Kalucki
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Jennifer C Potter
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Akiko Futakuchi-Tsuchida
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Gerhard J Weber
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sarah Dupras
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Hiroshi Tsuchida
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Lil Pabon
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Lili Wang
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Steven Kattman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - R Scott Thies
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Nathan Sniadecki
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Department of Mechanical Engineering, University of Washington, 3720 15(th) Avenue NE, Seattle, WA 98105, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - W Robb MacLellan
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Alessandro Bertero
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Charles E Murry
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
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4
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Cantero-Recasens G, Alonso-Marañón J, Lobo-Jarne T, Garrido M, Iglesias M, Espinosa L, Malhotra V. Reversing chemorefraction in colorectal cancer cells by controlling mucin secretion. eLife 2022; 11:73926. [PMID: 35131032 PMCID: PMC8846583 DOI: 10.7554/elife.73926] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 02/04/2022] [Indexed: 11/26/2022] Open
Abstract
Fifteen percent of colorectal cancer (CRC) cells exhibit a mucin hypersecretory phenotype, which is suggested to provide resistance to immune surveillance and chemotherapy. We now formally show that CRC cells build a barrier to chemotherapeutics by increasing mucins’ secretion. We show that low levels of KChIP3, a negative regulator of mucin secretion (Cantero-Recasens et al., 2018), is a risk factor for CRC patients’ relapse in a subset of untreated tumours. Our results also reveal that cells depleted of KChIP3 are four times more resistant (measured as cell viability and DNA damage) to chemotherapeutics 5-fluorouracil + irinotecan (5-FU+iri.) compared to control cells, whereas KChIP3-overexpressing cells are 10 times more sensitive to killing by chemotherapeutics. A similar increase in tumour cell death is observed upon chemical inhibition of mucin secretion by the sodium/calcium exchanger (NCX) blockers (Mitrovic et al., 2013). Finally, sensitivity of CRC patient-derived organoids to 5-FU+iri. increases 40-fold upon mucin secretion inhibition. Reducing mucin secretion thus provides a means to control chemoresistance of mucinous CRC cells and other mucinous tumours.
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Affiliation(s)
| | | | - Teresa Lobo-Jarne
- Cancer Research Program, Institut Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Marta Garrido
- Cancer Research Program, Institut Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Mar Iglesias
- Department of Pathology, Institut Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Lluis Espinosa
- Cancer Research Program, Institut Mar d'Investigacions Mèdiques, Barcelona, Spain
| | - Vivek Malhotra
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
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5
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Morciano G, Rimessi A, Patergnani S, Vitto VAM, Danese A, Kahsay A, Palumbo L, Bonora M, Wieckowski MR, Giorgi C, Pinton P. Calcium dysregulation in heart diseases: Targeting calcium channels to achieve a correct calcium homeostasis. Pharmacol Res 2022; 177:106119. [PMID: 35131483 DOI: 10.1016/j.phrs.2022.106119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/03/2022] [Indexed: 12/16/2022]
Abstract
Intracellular calcium signaling is a universal language source shared by the most part of biological entities inside cells that, all together, give rise to physiological and functional anatomical units, the organ. Although preferentially recognized as signaling between cell life and death processes, in the heart it assumes additional relevance considered the importance of calcium cycling coupled to ATP consumption in excitation-contraction coupling. The concerted action of a plethora of exchangers, channels and pumps inward and outward calcium fluxes where needed, to convert energy and electric impulses in muscle contraction. All this without realizing it, thousands of times, every day. An improper function of those proteins (i.e., variation in expression, mutations onset, dysregulated channeling, differential protein-protein interactions) being part of this signaling network triggers a short circuit with severe acute and chronic pathological consequences reported as arrhythmias, cardiac remodeling, heart failure, reperfusion injury and cardiomyopathies. By acting with chemical, peptide-based and pharmacological modulators of these players, a correction of calcium homeostasis can be achieved accompanied by an amelioration of clinical symptoms. This review will focus on all those defects in calcium homeostasis which occur in the most common cardiac diseases, including myocardial infarction, arrhythmia, hypertrophy, heart failure and cardiomyopathies. This part will be introduced by the state of the art on the proteins involved in calcium homeostasis in cardiomyocytes and followed by the therapeutic treatments that to date, are able to target them and to revert the pathological phenotype.
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Affiliation(s)
- Giampaolo Morciano
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
| | - Alessandro Rimessi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Simone Patergnani
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Veronica A M Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Alberto Danese
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Asrat Kahsay
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Laura Palumbo
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Massimo Bonora
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism. Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, RA, Italy.
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6
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Liu Z, Cheng Q, Ma X, Song M. Suppressing Effect of Na +/Ca 2+ Exchanger (NCX) Inhibitors on the Growth of Melanoma Cells. Int J Mol Sci 2022; 23:ijms23020901. [PMID: 35055084 PMCID: PMC8780355 DOI: 10.3390/ijms23020901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/05/2022] [Accepted: 01/12/2022] [Indexed: 12/28/2022] Open
Abstract
The role of calcium ion (Ca2+) signaling in tumorigenicity has received increasing attention in melanoma research. Previous Ca2+ signaling studies focused on Ca2+ entry routes, but rarely explored the role of Ca2+ extrusion. Functioning of the Na+/Ca2+ exchanger (NCX) on the plasma membrane is the major way of Ca2+ extrusion, but very few associations between NCX and melanoma have been reported. Here, we explored whether pharmacological modulation of the NCX could suppress melanoma and promise new therapeutic strategies. Methods included cell viability assay, Ca2+ imaging, immunoblotting, and cell death analysis. The NCX inhibitors SN-6 and YM-244769 were used to selectively block reverse operation of the NCX. Bepridil, KB-R7943, and CB-DMB blocked either reverse or forward NCX operation. We found that blocking the reverse NCX with SN-6 or YM-244769 (5–100 μM) did not affect melanoma cells or increase cytosolic Ca2+. Bepridil, KB-R7943, and CB-DMB all significantly suppressed melanoma cells with IC50 values of 3–20 μM. Bepridil and KB-R7943 elevated intracellular Ca2+ level of melanoma. Bepridil-induced melanoma cell death came from cell cycle arrest and enhanced apoptosis, which were all attenuated by the Ca2+ chelator BAPTA-AM. As compared with melanoma, normal melanocytes had lower NCX1 expression and were less sensitive to the cytotoxicity of bepridil. In conclusion, blockade of the forward but not the reverse NCX leads to Ca2+-related cell death in melanoma and the NCX is a potential drug target for cancer therapy.
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7
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BRAF and NRAS mutated melanoma: Different Ca 2+ responses, Na +/Ca 2+ exchanger expression, and sensitivity to inhibitors. Cell Calcium 2020; 90:102241. [PMID: 32562975 DOI: 10.1016/j.ceca.2020.102241] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 01/10/2023]
Abstract
Calcium is a ubiquitous intracellular second messenger, playing central roles in the regulation of several biological processes. Alterations in Ca2+ homeostasis and signaling are an important feature of tumor cells to acquire proliferative and survival advantages, which include structural and functional changes in storage capacity, channels, and pumps. Here, we investigated the differences in Ca2+ homeostasis in vemurafenib-responsive and non-responsive melanoma cells. Also, the expression of the Na+/Ca2+ exchanger (NCX) and the impact of its inhibition were studied. For this, it was used B-RAFV600E and NRASQ61R-mutated human melanoma cells. The intracellular Ca2+ chelator BAPTA-AM decreased the viability of SK-MEL-147 but not of SK-MEL-19 and EGTA sensitized NRASQ61R-mutated cells to vemurafenib. These cells also presented a smaller response to thapsargin and ionomycin regarding the cytosolic Ca2+ levels in relation to SK-MEL-19, which was associated to an increased expression of NCX1, NO basal levels, and sensitivity to NCX inhibitors. These data highlight the differences between B-RAFV600E and NRASQ61R-mutated melanoma cells in response to Ca2+ stimuli and point to the potential combination of clinically used chemotherapeutic drugs, including vemurafenib, with NCX inhibitors as a new therapeutic strategy to the treatment of melanoma.
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8
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Rose CR, Ziemens D, Verkhratsky A. On the special role of NCX in astrocytes: Translating Na +-transients into intracellular Ca 2+ signals. Cell Calcium 2019; 86:102154. [PMID: 31901681 DOI: 10.1016/j.ceca.2019.102154] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
As a solute carrier electrogenic transporter, the sodium/calcium exchanger (NCX1-3/SLC8A1-A3) links the trans-plasmalemmal gradients of sodium and calcium ions (Na+, Ca2+) to the membrane potential of astrocytes. Classically, NCX is considered to serve the export of Ca2+ at the expense of the Na+ gradient, defined as a "forward mode" operation. Forward mode NCX activity contributes to Ca2+ extrusion and thus to the recovery from intracellular Ca2+ signals in astrocytes. The reversal potential of the NCX, owing to its transport stoichiometry of 3 Na+ to 1 Ca2+, is, however, close to the astrocytes' membrane potential and hence even small elevations in the astrocytic Na+ concentration or minor depolarisations switch it into the "reverse mode" (Ca2+ import/Na+ export). Notably, transient Na+ elevations in the millimolar range are induced by uptake of glutamate or GABA into astrocytes and/or by the opening of Na+-permeable ion channels in response to neuronal activity. Activity-related Na+ transients result in NCX reversal, which mediates Ca2+ influx from the extracellular space, thereby generating astrocyte Ca2+ signalling independent from InsP3-mediated release from intracellular stores. Under pathological conditions, reverse NCX promotes cytosolic Ca2+ overload, while dampening Na+ elevations of astrocytes. This review provides an overview on our current knowledge about this fascinating transporter and its special functional role in astrocytes. We shall delineate that Na+-driven, reverse NCX-mediated astrocyte Ca2+ signals are involved neurone-glia interaction. Na+ transients, translated by the NCX into Ca2+ elevations, thereby emerge as a new signalling pathway in astrocytes.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
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9
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Watanabe Y. Cardiac Na +/Ca 2+ exchange stimulators among cardioprotective drugs. J Physiol Sci 2019; 69:837-849. [PMID: 31664641 PMCID: PMC10717683 DOI: 10.1007/s12576-019-00721-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/18/2019] [Indexed: 02/06/2023]
Abstract
We previously reviewed our study of the pharmacological properties of cardiac Na+/Ca2+ exchange (NCX1) inhibitors among cardioprotective drugs, such as amiodarone, bepridil, dronedarone, cibenzoline, azimilide, aprindine, and benzyl-oxyphenyl derivatives (Watanabe et al. in J Pharmacol Sci 102:7-16, 2006). Since then we have continued our studies further and found that some cardioprotective drugs are NCX1 stimulators. Cardiac Na+/Ca2+ exchange current (INCX1) was stimulated by nicorandil (a hybrid ATP-sensitive K+ channel opener), pinacidil (a non-selective ATP-sensitive K+ channel opener), flecainide (an antiarrhythmic drug), and sodium nitroprusside (SNP) (an NO donor). Sildenafil (a phosphodiesterase-5 inhibitor) further increased the pinacidil-induced augmentation of INCX1. In paper, here I review the NCX stimulants that enhance NCX function among the cardioprotective agents we examined such as nicorandil, pinacidil, SNP, sildenafil and flecainide, in addition to atrial natriuretic (ANP) and dofetilide, which were reported by other investigators.
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Affiliation(s)
- Yasuhide Watanabe
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu, 431-3192, Japan.
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10
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Cantero-Recasens G, Butnaru CM, Brouwers N, Mitrovic S, Valverde MA, Malhotra V. Sodium channel TRPM4 and sodium/calcium exchangers (NCX) cooperate in the control of Ca 2+-induced mucin secretion from goblet cells. J Biol Chem 2018; 294:816-826. [PMID: 30482841 DOI: 10.1074/jbc.ra117.000848] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/21/2018] [Indexed: 01/08/2023] Open
Abstract
Regulated mucin secretion is essential for the formation of the mucus layer that protects the underlying epithelial cells from foreign particles. Alterations in the quantity or quality of secreted mucins are therefore detrimental to airway and colon physiology. Based on various biochemical assays in several human cell lines, we report here that Na+/Ca2+ exchanger 2 (NCX2) works in conjunction with transient receptor potential cation channel subfamily M member 4 (TRPM4), and perhaps TRPM5, Na+ channels to control Ca2+-mediated secretion of both mucin 2 (MUC2) and MUC5AC from HT29-18N2 colonic cancer cells. Differentiated normal bronchial epithelial (NHBE) cells and tracheal cells from patients with cystic fibrosis (CFT1-LC3) expressed only TRPM4 and all three isoforms of NCXs. Blocking the activity of TRPM4 or NCX proteins abrogated MUC5AC secretion from NHBE and CFT1-LC3 cells. Altogether, our findings reveal that NCX and TRPM4/TRPM5 are both required for mucin secretion. We therefore propose that these two proteins could be potential pharmacological targets to control mucus-related pathologies such as cystic fibrosis.
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Affiliation(s)
- Gerard Cantero-Recasens
- From the Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Cristian M Butnaru
- From the Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Nathalie Brouwers
- From the Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Sandra Mitrovic
- the University Hospital of Basel, Clinical Chemistry, Petersgraben 4, 4031 Basel, Switzerland
| | - Miguel A Valverde
- the Laboratory of Molecular Physiology, Faculty of Health and Life Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Catalonia, Spain, and
| | - Vivek Malhotra
- From the Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain, .,the Universitat Pompeu Fabra (UPF), Barcelona, Spain.,the Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain
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11
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Lillo MA, Gaete PS, Puebla M, Ardiles NM, Poblete I, Becerra A, Simon F, Figueroa XF. Critical contribution of Na +-Ca 2+ exchanger to the Ca 2+-mediated vasodilation activated in endothelial cells of resistance arteries. FASEB J 2018; 32:2137-2147. [PMID: 29217667 DOI: 10.1096/fj.201700365rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Na+-Ca2+ exchanger (NCX) contributes to control the intracellular free Ca2+ concentration ([Ca2+]i), but the functional activation of NCX reverse mode (NCXrm) in endothelial cells is controversial. We evaluated the participation of NCXrm-mediated Ca2+ uptake in the endothelium-dependent vasodilation of rat isolated mesenteric arterial beds. In phenylephrine-contracted mesenteries, the acetylcholine (ACh)-induced vasodilation was abolished by treatment with the NCXrm blockers SEA0400, KB-R7943, or SN-6. Consistent with that, the ACh-induced hyperpolarization observed in primary cultures of mesenteric endothelial cells and in smooth muscle of isolated mesenteric resistance arteries was attenuated by KB-R7943 and SEA0400, respectively. In addition, both blockers abolished the NO production activated by ACh in intact mesenteric arteries. In contrast, the inhibition of NCXrm did not affect the vasodilator responses induced by the Ca2+ ionophore, ionomycin, and the NO donor, S-nitroso- N-acetylpenicillamine. Furthermore, SEA0400, KB-R7943, and a small interference RNA directed against NCX1 blunted the increase in [Ca2+]i induced by ACh or ATP in cultured endothelial cells. The analysis by proximity ligation assay showed that the NO-synthesizing enzyme, eNOS, and NCX1 were associated in endothelial cell caveolae of intact mesenteric resistance arteries. These results indicate that the activation of NCXrm has a central role in Ca2+-mediated vasodilation initiated by ACh in endothelial cells of resistance arteries.-Lillo, M. A., Gaete, P. S., Puebla, M., Ardiles, N. M., Poblete, I., Becerra, A., Simon, F., Figueroa, X. F. Critical contribution of Na+-Ca2+ exchanger to the Ca2+-mediated vasodilation activated in endothelial cells of resistance arteries.
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Affiliation(s)
- Mauricio A Lillo
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo S Gaete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariela Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás M Ardiles
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Inés Poblete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alvaro Becerra
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Facultad de Salud, Deporte y Recreación, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Felipe Simon
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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12
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Banach M, Popławska M, Borowicz-Reutt KK. Amiodarone, a multi-channel blocker, enhances anticonvulsive effect of carbamazepine in the mouse maximal electroshock model. Epilepsy Res 2018; 140:105-110. [PMID: 29329017 DOI: 10.1016/j.eplepsyres.2018.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/07/2017] [Accepted: 01/03/2018] [Indexed: 12/11/2022]
Abstract
Cardiac arrhythmia may occur in the course of epilepsy. Simultaneous therapy of the two diseases might be complicated by drug interactions since antiarrhythmic and antiepileptic agents share some molecular targets. The aim of this study was to evaluate the influence of amiodarone, an antiarrhythmic drug working as a multi-channel blocker, on the protective activity of four classical antiepileptic drugs in the maximal electroshock test in mice. Amiodarone at doses up to 75 mg/kg did not affect the electroconvulsive threshold in mice. Acute amiodarone at the dose of 75 mg/kg significantly potentiated the anticonvulsive effect of carbamazepine, but not that of valproate, phenytoin or phenobarbital in the maximal electroshock-induced seizures in mice. The antiarrhythmic agent and its combinations with antiepileptic drugs did not impair motor performance or long-term memory in mice, except for the combination of amiodarone and phenobarbital. Brain concentrations of antiepileptic drugs were not changed. Despite favourable impact of amiodarone on the anticonvulsive action of carbamazepine in the maximal electroshock, co-administration of the two drugs should be carefully monitored in clinical conditions. Further studies are necessary to evaluate effects of chronic treatment with amiodarone on seizure activity and the action of antiepileptic drugs.
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Affiliation(s)
- Monika Banach
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, PL-20-954, Lublin, Poland
| | - Monika Popławska
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, PL-20-954, Lublin, Poland
| | - Kinga K Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, PL-20-954, Lublin, Poland.
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13
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Fontaine AK, Gibson EA, Caldwell JH, Weir RF. Optical Read-out of Neural Activity in Mammalian Peripheral Axons: Calcium Signaling at Nodes of Ranvier. Sci Rep 2017; 7:4744. [PMID: 28720792 PMCID: PMC5516017 DOI: 10.1038/s41598-017-03541-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/28/2017] [Indexed: 12/11/2022] Open
Abstract
Current neural interface technologies have serious limitations for advanced prosthetic and therapeutic applications due primarily to their lack of specificity in neural communication. An optogenetic approach has the potential to provide single cell/axon resolution in a minimally invasive manner by optical interrogation of light-sensitive reporters and actuators. Given the aim of reading neural activity in the peripheral nervous system, this work has investigated an activity-dependent signaling mechanism in the peripheral nerve. We demonstrate action potential evoked calcium signals in mammalian tibial nerve axons using an in vitro mouse model with a dextran-conjugated fluorescent calcium indicator. Spatial and temporal dynamics of the signal are presented, including characterization of frequency-modulated amplitude. Pharmacological experiments implicate T-type CaV channels and sodium-calcium exchanger (NCX) as predominant mechanisms of calcium influx. This work shows the potential of using calcium-associated optical signals for neural activity read-out in peripheral nerve axons.
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Affiliation(s)
- Arjun K Fontaine
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA.
| | - Emily A Gibson
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA
| | - John H Caldwell
- Department of Cell and Developmental Biology, University of Colorado - Anschutz Medical Campus, Colorado, USA
| | - Richard F Weir
- Department of Bioengineering, University of Colorado - Anschutz Medical Campus, Colorado, USA
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14
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Wu SN, Chern JH, Shen S, Chen HH, Hsu YT, Lee CC, Chan MH, Lai MC, Shie FS. Stimulatory actions of a novel thiourea derivative on large-conductance, calcium-activated potassium channels. J Cell Physiol 2017; 232:3409-3421. [PMID: 28075010 DOI: 10.1002/jcp.25788] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 01/14/2023]
Abstract
In this study, we examine whether an anti-inflammatory thiourea derivative, compound #326, actions on ion channels. The effects of compound #326 on Ca2+ -activated K+ channels were evaluated by patch-clamp recordings obtained in cell-attached, inside-out or whole-cell configuration. In pituitary GH3 cells, compound #326 increased the amplitude of Ca2+ -activated K+ currents (IK(Ca) ) with an EC50 value of 11.6 μM, which was reversed by verruculogen, but not tolbutamide or TRAM-34. Under inside-out configuration, a bath application of compound #326 raised the probability of large-conductance Ca2+ -activated K+ (BKCa ) channels. The activation curve of BKCa channels was shifted to less depolarised potential with no modification of the gating charge of the curve; consequently, the difference of free energy was reduced in the presence of this compound. Compound #326-stimulated activity of BKCa channels is explained by a shortening of mean closed time, despite its inability to alter single-channel conductance. Neither delayed-rectifier nor erg-mediated K+ currents was modified. Compound #326 decreased the peak amplitude of voltage-gated Na+ current with no clear change in the overall current-voltage relationship of this current. In HEK293T cells expressing α-hSlo, compound #326 enhanced BKCa channels effectively. Intriguingly, the inhibitory actions of compound #326 on interleukin 1β in lipopolysaccharide-activated microglia were significantly reversed by verruculogen, whereas BKCa channel inhibitors suppressed the expressions of inducible nitric oxide synthase. The BKCa channels could be an important target for compound #326 if similar in vivo results occur, and the multi-functionality of BKCa channels in modulating microglial immunity merit further investigation.
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Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan
| | - Jyh-Haur Chern
- Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Santai Shen
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Hwei-Hisen Chen
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Ying-Ting Hsu
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Chih-Chin Lee
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
| | - Ming-Huan Chan
- Institute of Neuroscience, National Chengchi University, Taipei City, Taiwan
| | - Ming-Chi Lai
- Department of Pediatrics, Chi Mei Medical Center, Tainan City, Taiwan
| | - Feng-Shiun Shie
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan
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15
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Averin AS, Kosarsky LS, Tarlachkov SV, Vekhnik VA, Averina IV, Alekseev AE, Fesenko EE, Nakipova OV. The effects of KB-R7943, an inhibitor of reverse Na+/Ca2+ exchange, on the force of contraction of papillary muscles in the heart of the ground squirrel Spermophilus undulatus. Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s000635091701002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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16
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Petrou T, Olsen HL, Thrasivoulou C, Masters JR, Ashmore JF, Ahmed A. Intracellular Calcium Mobilization in Response to Ion Channel Regulators via a Calcium-Induced Calcium Release Mechanism. J Pharmacol Exp Ther 2016; 360:378-387. [PMID: 27980039 PMCID: PMC5267512 DOI: 10.1124/jpet.116.236695] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 11/14/2016] [Indexed: 01/19/2023] Open
Abstract
Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been used to treat a range of human diseases, on [Ca2+]i release, by ratiometric calcium imaging. We show that six such modulators [amiodarone (Ami), dofetilide, furosemide (Fur), minoxidil (Min), loxapine (Lox), and Nicorandil] initiate release of [Ca2+]i in prostate and breast cancer cell lines, PC3 and MCF7, respectively. Whole-cell currents in PC3 cells were inhibited by the compounds tested in patch-clamp experiments in a concentration-dependent manner. In all cases [Ca2+]i was increased by modulator concentrations comparable to those used clinically. The increase in [Ca2+]i in response to Ami, Fur, Lox, and Min was reduced significantly (P < 0.01) when the external calcium was reduced to nM concentration by chelation with EGTA. The data suggest that many ion channel regulators mobilize [Ca2+]i. We suggest a mechanism whereby calcium-induced calcium release is implicated; such a mechanism may be important for understanding the action of these compounds.
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Affiliation(s)
- Terry Petrou
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Hervør L Olsen
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Christopher Thrasivoulou
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - John R Masters
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Jonathan F Ashmore
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
| | - Aamir Ahmed
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, United Kingdom (T.P., A.A.); Sophion Bioscience A/S, Biolin Scientific, Ballerup, Denmark (H.L.O.); Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics (C.T.), Division of Surgery (J.R.M.), and Ear Institute, (J.F.A.), University College London, London, United Kingdom
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17
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Yamashita K, Watanabe Y, Kita S, Iwamoto T, Kimura J. Inhibitory effect of YM-244769, a novel Na +/Ca 2+ exchanger inhibitor on Na +/Ca 2+ exchange current in guinea pig cardiac ventricular myocytes. Naunyn Schmiedebergs Arch Pharmacol 2016; 389:1205-1214. [PMID: 27480939 DOI: 10.1007/s00210-016-1282-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/21/2016] [Indexed: 11/28/2022]
Abstract
Recently, YM-244769 (N-(3-aminobenzyl)-6-{4-[(3-fluorobenzyl)oxy]phenoxy} nicotinamide) has been reported as a new potent and selective Na+/Ca2+ exchange (NCX) inhibitor by using various cells transfected with NCX using the 45Ca2+ fluorescent technique. However, the electrophysiological study of YM-244769 on NCX had not been performed in the mammalian heart. We examined the effects of YM-244769 on NCX current (INCX) in single cardiac ventricular myocytes of guinea pigs by using the whole-cell voltage clamp technique. YM-244769 suppressed the bidirectional INCX in a concentration-dependent manner. The IC50 values of YM-244769 for the bidirectional outward and inward INCX were both about 0.1 μM. YM-244769 suppressed the unidirectional outward INCX (Ca2+ entry mode) with an IC50 value of 0.05 μM. The effect on the unidirectional inward INCX (Ca2+ exit mode) was less potent, with 10 μM of YM-244769 resulting in the inhibition of only about 50 %. At 5 mM intracellular Na+ concentration, YM-244769 suppressed INCX more potently than it did at 0 mM [Na+]i. Intracellular application of trypsin via the pipette solution did not change the blocking effect of YM-244769. In conclusion, YM-244769 inhibits the Ca2+ entry mode of NCX more potently than the Ca2+ exit mode, and inhibition by YM-244769 is [Na+]i-dependent and trypsin-insensitive. These characteristics are similar to those of other benzyloxyphenyl derivative NCX inhibitors such as KB-R7943, SEA0400, and SN-6. The potency of YM-244769 as an NCX1 inhibitor is higher than those of KB-R7943 and SN-6 and is similar to that of SEA0400.
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Affiliation(s)
- Kanna Yamashita
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasuhide Watanabe
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| | - Satomi Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Junko Kimura
- Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima, Japan
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18
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Sodium Channels, Mitochondria, and Axonal Degeneration in Peripheral Neuropathy. Trends Mol Med 2016; 22:377-390. [DOI: 10.1016/j.molmed.2016.03.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 12/19/2022]
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19
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Ozawa M, Komatsu T, Sato Y, Kunugita F, Tachibana H, Tashiro A, Okabayashi H, Nakamura M. Comparison of the effects of bepridil and aprindine for the prevention of atrial fibrillation after cardiac and aortic surgery: A prospective randomized study. J Arrhythm 2015; 31:302-6. [PMID: 26550087 PMCID: PMC4600894 DOI: 10.1016/j.joa.2015.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/01/2015] [Accepted: 04/05/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Approximately one-third of the patients undergoing cardiovascular surgery reportedly experience paroxysmal atrial fibrillation (AF) during the postoperative period. However, the usefulness of antiarrhythmic drugs for preventing postoperative AF recurrence in the Japanese population has not been extensively studied. METHODS From a total of 118 patients who developed postoperative paroxysmal AF between April 2009 and March 2011, 72 patients (45 men, mean age 68±8 years) requiring treatment for postoperative AF due to symptoms lasting ≥30 min were enrolled to prospectively investigate the efficacy of oral bepridil (100 mg/day, n=37) or aprindine (40 mg/day, n=35). RESULT The AF recurrence-free survival rates at 1, 3, 7, and 14 days were 100%, 94%, 57%, and 49%, respectively, in the aprindine group, and 100%, 97%, 86%, and 76%, respectively, in the bepridil group (P=0.028, aprindine vs. bepridil). CONCLUSION Bepridil, at a fixed dose of 100 mg/day, was considered to be more effective than a routine dose of aprindine for the prevention of postoperative AF recurrence.
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Affiliation(s)
- Mahito Ozawa
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Takashi Komatsu
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Yoshihiro Sato
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Fusanori Kunugita
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Hideaki Tachibana
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Atsushi Tashiro
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
| | - Hitoshi Okabayashi
- Department of Cardiovascular Surgery, Iwate Medical University School of Medicine, Morioka, Japan
| | - Motoyuki Nakamura
- Division of Cardioangiology, Nephrology and Endocrinology, Department of Internal Medicine and Memorial Heart Center, Iwate Medical University School of Medicine, Morioka, Japan
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20
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Estacion M, Vohra BPS, Liu S, Hoeijmakers J, Faber CG, Merkies ISJ, Lauria G, Black JA, Waxman SG. Ca2+ toxicity due to reverse Na+/Ca2+ exchange contributes to degeneration of neurites of DRG neurons induced by a neuropathy-associated Nav1.7 mutation. J Neurophysiol 2015; 114:1554-64. [PMID: 26156380 DOI: 10.1152/jn.00195.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/06/2015] [Indexed: 12/19/2022] Open
Abstract
Gain-of-function missense mutations in voltage-gated sodium channel Nav1.7 have been linked to small-fiber neuropathy, which is characterized by burning pain, dysautonomia and a loss of intraepidermal nerve fibers. However, the mechanistic cascades linking Nav1.7 mutations to axonal degeneration are incompletely understood. The G856D mutation in Nav1.7 produces robust changes in channel biophysical properties, including hyperpolarized activation, depolarized inactivation, and enhanced ramp and persistent currents, which contribute to the hyperexcitability exhibited by neurons containing Nav1.8. We report here that cell bodies and neurites of dorsal root ganglion (DRG) neurons transfected with G856D display increased levels of intracellular Na(+) concentration ([Na(+)]) and intracellular [Ca(2+)] following stimulation with high [K(+)] compared with wild-type (WT) Nav1.7-expressing neurons. Blockade of reverse mode of the sodium/calcium exchanger (NCX) or of sodium channels attenuates [Ca(2+)] transients evoked by high [K(+)] in G856D-expressing DRG cell bodies and neurites. We also show that treatment of WT or G856D-expressing neurites with high [K(+)] or 2-deoxyglucose (2-DG) does not elicit degeneration of these neurites, but that high [K(+)] and 2-DG in combination evokes degeneration of G856D neurites but not WT neurites. Our results also demonstrate that 0 Ca(2+) or blockade of reverse mode of NCX protects G856D-expressing neurites from degeneration when exposed to high [K(+)] and 2-DG. These results point to [Na(+)] overload in DRG neurons expressing mutant G856D Nav1.7, which triggers reverse mode of NCX and contributes to Ca(2+) toxicity, and suggest subtype-specific blockade of Nav1.7 or inhibition of reverse NCX as strategies that might slow or prevent axon degeneration in small-fiber neuropathy.
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Affiliation(s)
- M Estacion
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut; Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - B P S Vohra
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut; Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - S Liu
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut; Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - J Hoeijmakers
- Department of Neurology, University Medical Center Maastricht, Maastricht, the Netherlands
| | - C G Faber
- Department of Neurology, University Medical Center Maastricht, Maastricht, the Netherlands
| | - I S J Merkies
- Department of Neurology, University Medical Center Maastricht, Maastricht, the Netherlands; Department of Neurology, Spaarne Hospital, Hoofddorp, the Netherlands; and
| | - G Lauria
- Neuroalgology Unit IRCCS Foundation "Carlo Besta" Neurological Institute, Milan, Italy
| | - J A Black
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut; Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - S G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut; Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut;
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Kawabata M, Yokoyama Y, Sasaki T, Tao S, Ihara K, Shirai Y, Sasano T, Goya M, Furukawa T, Isobe M, Hirao K. Severe iatrogenic bradycardia related to the combined use of beta-blocking agents and sodium channel blockers. Clin Pharmacol 2015; 7:29-36. [PMID: 25733934 PMCID: PMC4337503 DOI: 10.2147/cpaa.s77021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose Drug-induced bradycardia is common during antiarrhythmic therapy; the major culprits are beta-blockers. However, whether other antiarrhythmic drugs are also a significant cause of this, alone or in combination with beta-blockers, is not well known. Methods We retrospectively investigated the records of all patients hospitalized at our institution for drug-related bradycardia from the years 2004 to 2012. Patients with cardiac disease and electrolytic or hormonal abnormalities that could cause bradyarrhythmias were excluded. Results Eight patients were identified (mean age, 79±5 years; range, 71–85 years; 6 women). Three patients were taking only beta-blockers (hereafter referred to as the BB group), while five patients were on both beta-blockers and Na channel blockers (hereafter referred to as the BB + Na group). Heart rates ranged from 20∼49 beats/minute on arrival. The initial electrocardiogram showed sinus bradycardia (n=6) or sinus arrest with escape beats (n=2). QRS duration was 80–100 ms. The clinical presentation of the BB + Na group was considerably worse than that of the BB group, and included cardiogenic shock and heart failure. Four of the BB + Na patients had been on their medications for over 300 days. The BB group recovered solely with drug discontinuation, while 4 of the 5 patients in the BB + Na group needed additional treatments, such as intravenous administration of atropine or adrenergic agonist and temporary pacing. Bradycardia did not recur during follow-up (median, 687 days). Conclusion Although wide QRS ventricular tachyarrhythmia is a better known proarrhythmic effect of Na channel blockers, life-threatening bradycardia may also occur in combination with beta-blockers in the elderly, even months after the start of medication, and at plasma concentrations that do not prolong QRS width.
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Affiliation(s)
- Mihoko Kawabata
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yasuhiro Yokoyama
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takeshi Sasaki
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Susumu Tao
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kensuke Ihara
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yasuhiro Shirai
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuo Sasano
- Department of Biofunctional Informatics, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masahiko Goya
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsushi Furukawa
- Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kenzo Hirao
- Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan
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22
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Magi S, Nasti AA, Gratteri S, Castaldo P, Bompadre S, Amoroso S, Lariccia V. Gram-negative endotoxin lipopolysaccharide induces cardiac hypertrophy: Detrimental role of Na+–Ca2+ exchanger. Eur J Pharmacol 2015; 746:31-40. [DOI: 10.1016/j.ejphar.2014.10.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 10/22/2014] [Accepted: 10/25/2014] [Indexed: 01/18/2023]
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Effects of renal Na+/Ca2+ exchanger 1 inhibitor (SEA0400) treatment on electrolytes, renal function and hemodynamics in rats. Clin Exp Nephrol 2014; 19:585-90. [PMID: 25410661 DOI: 10.1007/s10157-014-1053-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 11/01/2014] [Indexed: 01/30/2023]
Abstract
BACKGROUND Na(+)/Ca(2+) exchanger 1 (NCX1) controls intracellular Ca(2+) concentration in various cell types. In the kidney, NCX1 is expressed mainly in the distal tubular basolateral membrane as well as in vascular smooth muscle. Tubular NCX1 is involved in Ca(2+) reabsorption, and NCX1 in renal arterioles may control intraglomerular pressure. However, the functions of renal NCX1 have not been studied in vivo. Therefore, this study examined the effects of renal NCX1 blockade on water and solute metabolism, renal function and blood pressure in rats. METHODS Wistar-Kyoto rats were uninephrectomized, and an osmotic mini pump was implanted to infuse the remnant kidney cortex with a specific NCX1 inhibitor, SEA0400 (SEA), or vehicle for 7 days. RESULTS Serum Ca(2+) concentration and urinary Ca(2+) excretion were similar between the vehicle- and SEA-treated groups. However, serum phosphate was significantly decreased by 8 % in the SEA group, with similar urinary phosphate excretion between the two groups. Systolic blood pressure was higher in the SEA group (117 ± 3 vs. 126 ± 1 mmHg, n = 9-11), with a 1.6-fold increase in plasma aldosterone concentration. However, SEA significantly reduced urinary protein excretion and the glomerular sectional area by 16 and 8 %, respectively. Similar experiment in spontaneously hypertensive rats produced different results. CONCLUSION Renal SEA treatment reduced serum phosphate concentration, urinary protein and glomerular size with higher systemic blood pressure compared to control Wistar-Kyoto rats. Further study on renal NCX1 may be beneficial in delineating the pathophysiology of glomerular pressure control and calcium/phosphate regulations.
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Scheff NN, Yilmaz E, Gold MS. The properties, distribution and function of Na(+)-Ca(2+) exchanger isoforms in rat cutaneous sensory neurons. J Physiol 2014; 592:4969-93. [PMID: 25239455 PMCID: PMC4259538 DOI: 10.1113/jphysiol.2014.278036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 09/10/2014] [Indexed: 11/08/2022] Open
Abstract
The Na(+)-Ca(2+) exchanger (NCX) appears to play an important role in the regulation of the high K(+)-evoked Ca(2+) transient in putative nociceptive dorsal root ganglion (DRG) neurons. The purpose of the present study was to (1) characterize the properties of NCX activity in subpopulations of DRG neurons, (2) identify the isoform(s) underlying NCX activity, and (3) begin to assess the function of the isoform(s) in vivo. In retrogradely labelled neurons from the glabrous skin of adult male Sprague-Dawley rats, NCX activity, as assessed with fura-2-based microfluorimetry, was only detected in putative nociceptive IB4+ neurons. There were two modes of NCX activity: one was evoked in response to relatively large and long lasting (∼325 nm for >12 s) increases in the concentration of intracellular Ca(2+) ([Ca(2+)]i), and a second was active at resting [Ca(2+)]i > ∼150 nm. There also were two modes of evoked activity: one that decayed relatively rapidly (<5 min) and a second that persisted (>10 min). Whereas mRNA encoding all three NCX isoforms (NCX1-3) was detected in putative nociceptive cutaneous neurons with single cell PCR, pharmacological analysis and small interfering RNA (siRNA) knockdown of each isoform in vivo suggested that NCX2 and 3 were responsible for NCX activity. Western blot analyses suggested that NCX isoforms were differentially distributed within sensory neurons. Functional assays of excitability, action potential propagation, and nociceptive behaviour suggest NCX activity has little influence on excitability per se, but instead influences axonal conduction velocity, resting membrane potential, and nociceptive threshold. Together these results indicate that the function of NCX in the regulation of [Ca(2+)]i in putative nociceptive neurons may be unique relative to other cells in which these exchanger isoforms have been characterized and it has the potential to influence sensory neuron properties at multiple levels.
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Affiliation(s)
- N N Scheff
- The Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - E Yilmaz
- The Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - M S Gold
- The Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
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25
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Maltsev VA, Yaniv Y, Maltsev AV, Stern MD, Lakatta EG. Modern perspectives on numerical modeling of cardiac pacemaker cell. J Pharmacol Sci 2014; 125:6-38. [PMID: 24748434 DOI: 10.1254/jphs.13r04cr] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent "coupled-clock" theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age.
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Affiliation(s)
- Victor A Maltsev
- Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, NIH, USA
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26
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Sodium channels contribute to degeneration of dorsal root ganglion neurites induced by mitochondrial dysfunction in an in vitro model of axonal injury. J Neurosci 2014; 33:19250-61. [PMID: 24305821 DOI: 10.1523/jneurosci.2148-13.2013] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Axonal degeneration occurs in multiple neurodegenerative disorders of the central and peripheral nervous system. Although the underlying molecular pathways leading to axonal degeneration are incompletely understood, accumulating evidence suggests contributions of impaired mitochondrial function, disrupted axonal transport, and/or dysfunctional intracellular Ca(2+)-homeostasis in the injurious cascade associated with axonal degeneration. Utilizing an in vitro model of axonal degeneration, we studied a subset of mouse peripheral sensory neurons in which neurites were exposed selectively to conditions associated with the pathogenesis of axonal neuropathies in vivo. Rotenone-induced mitochondrial dysfunction resulted in neurite degeneration accompanied by reduced ATP levels and increased ROS levels in neurites. Blockade of voltage-gated sodium channels with TTX and reverse (Ca(2+)-importing) mode of the sodium-calcium exchanger (NCX) with KB-R7943 partially protected rotenone-treated neurites from degeneration, suggesting a contribution of sodium channels and reverse NCX activity to the degeneration of neurites resulting from impaired mitochondrial function. Pharmacological inhibition of the Na(+)/K(+)-ATPase with ouabain induced neurite degeneration, which was attenuated by TTX and KB-R7943, supporting a contribution of sodium channels in axonal degenerative pathways accompanying impaired Na(+)/K(+)-ATPase activity. Conversely, oxidant stress (H2O2)-induced neurite degeneration was not attenuated by TTX. Our results demonstrate that both energetic and oxidative stress targeted selectively to neurites induces neurite degeneration and that blockade of sodium channels and of reverse NCX activity blockade partially protects neurites from injury due to energetic stress, but not from oxidative stress induced by H2O2.
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27
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Mechanisms of calcium absorption by anterior and posterior segments of the intestinal tract of juvenile lake sturgeon. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:293-301. [DOI: 10.1016/j.cbpa.2013.06.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/27/2013] [Accepted: 06/27/2013] [Indexed: 11/23/2022]
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Khananshvili D. The SLC8 gene family of sodium-calcium exchangers (NCX) - structure, function, and regulation in health and disease. Mol Aspects Med 2013; 34:220-35. [PMID: 23506867 DOI: 10.1016/j.mam.2012.07.003] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 03/08/2012] [Indexed: 01/12/2023]
Abstract
The SLC8 gene family encoding Na(+)/Ca(2+) exchangers (NCX) belongs to the CaCA (Ca(2+)/Cation Antiporter) superfamily. Three mammalian genes (SLC8A1, SLC8A2, and SLC8A3) and their splice variants are expressed in a tissue-specific manner to mediate Ca(2+)-fluxes across the cell-membrane and thus, significantly contribute to regulation of Ca(2+)-dependent events in many cell types. A long-wanted mitochondrial Na(+)/Ca(2+) exchanger has been recently identified as NCLX protein, representing a gene product of SLC8B1. Distinct NCX isoform/splice variants contribute to excitation-contraction coupling, long-term potentiation of the brain and learning, blood pressure regulation, immune response, neurotransmitter and insulin secretion, mitochondrial bioenergetics, etc. Altered expression and regulation of NCX proteins contribute to distorted Ca(2+)-homeostasis in heart failure, arrhythmia, cerebral ischemia, hypertension, diabetes, renal Ca(2+) reabsorption, muscle dystrophy, etc. Recently, high-resolution X-ray structures of Ca(2+)-binding regulatory domains of eukaryotic NCX and of full-size prokaryotic NCX have become available and the dynamic properties have been analyzed by advanced biophysical approaches. Molecular silencing/overexpression of NCX in cellular systems and organ-specific KO mouse models provided useful information on the contribution of distinct NCX variants to cellular and systemic functions under various pathophysiological conditions. Selective inhibition or activation of predefined NCX variants in specific diseases might have clinical relevance, although this breakthrough has not yet been realized. A better understanding of the underlying molecular mechanisms as well as the development of in vitro procedures for high-throughput screening of "drug-like" compounds may lead to selective pharmacological targeting of NCX variants.
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Affiliation(s)
- Daniel Khananshvili
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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29
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Magi S, Arcangeli S, Castaldo P, Nasti AA, Berrino L, Piegari E, Bernardini R, Amoroso S, Lariccia V. Glutamate-induced ATP synthesis: relationship between plasma membrane Na+/Ca2+ exchanger and excitatory amino acid transporters in brain and heart cell models. Mol Pharmacol 2013; 84:603-14. [PMID: 23913256 DOI: 10.1124/mol.113.087775] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
It is known that glutamate (Glu), the major excitatory amino acid in the central nervous system, can be an essential source for cell energy metabolism. Here we investigated the role of the plasma membrane Na(+)/Ca(2+) exchanger (NCX) and the excitatory amino acid transporters (EAATs) in Glu uptake and recycling mechanisms leading to ATP synthesis. We used different cell lines, such as SH-SY5Y neuroblastoma, C6 glioma and H9c2 as neuronal, glial, and cardiac models, respectively. We first observed that Glu increased ATP production in SH-SY5Y and C6 cells. Pharmacological inhibition of either EAAT or NCX counteracted the Glu-induced ATP synthesis. Furthermore, Glu induced a plasma membrane depolarization and an intracellular Ca(2+) increase, and both responses were again abolished by EAAT and NCX blockers. In line with the hypothesis of a mutual interplay between the activities of EAAT and NCX, coimmunoprecipitation studies showed a physical interaction between them. We expanded our studies on EAAT/NCX interplay in the H9c2 cells. H9c2 expresses EAATs but lacks endogenous NCX1 expression. Glu failed to elicit any significant response in terms of ATP synthesis, cell depolarization, and Ca(2+) increase unless a functional NCX1 was introduced in H9c2 cells by stable transfection. Moreover, these responses were counteracted by EAAT and NCX blockers, as observed in SH-SY5Y and C6 cells. Collectively, these data suggest that plasma membrane EAAT and NCX are both involved in Glu-induced ATP synthesis, with NCX playing a pivotal role.
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Affiliation(s)
- Simona Magi
- Department of Biomedical Sciences and Public Health, School of Medicine, University Politecnica of Marche, Ancona, Italy (S.M., S.Ar., P.C., A.A.N., S.Am., V.L.); Department of Experimental Medicine, Second University of Naples, Naples, Italy (L.B., E.P.); and Department of Clinical and Molecular Biomedicine, School of Medicine, University of Catania, Catania, Italy (R.B.)
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Calcium influx through reversed NCX controls migration of microglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:289-94. [PMID: 23224888 DOI: 10.1007/978-1-4614-4756-6_24] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Microglia, the immune cells of the central nervous system (CNS), are busy and vigilant guards of the adult brain, which scan brain parenchyma for damage and activate in response to lesions. Release of danger signals/chemoattractants at the site of damage initiates microglial activation and stimulates migration. The main candidate for a chemoattractant sensed by microglia is adenosine triphosphate (ATP); however, many other substances can have similar effects. Some neuropeptides such as angiotensin II, bradykinin, endothelin, galanin and neurotensin are also chemoattractants for microglia. Among them, bradykinin increases microglial migration using mechanism distinct from that of ATP. Bradykinin-induced migration is controlled by a G(i/o)-protein-independent pathway, while ATP-induced migration involves G(i/o) proteins as well as mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK)-dependent pathway. Galanin was reported to share certain signalling cascades with bradykinin; however, this overlap is only partial. Bradykinin, for example, stimulates Ca(2+) influx through the reversed Na(+)/Ca(2+) exchange (NCX), whereas galanin induces intracellular Ca(2+) mobilization by inositol-3,4,5-trisphosphate (InsP(3))-dependent Ca(2+) release from the intracellular store. These differences in signal cascades indicate that different chemoattractants such as ATP, bradykinin and galanin control distinct microglial functions in pathological conditions such as lesion and inflammation and NCX contributes to a special case of microglial migration.
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Persson AK, Liu S, Faber CG, Merkies ISJ, Black JA, Waxman SG. Neuropathy-associated NaV1.7 variant I228M impairs integrity of dorsal root ganglion neuron axons. Ann Neurol 2012; 73:140-5. [DOI: 10.1002/ana.23725] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/25/2012] [Accepted: 08/03/2012] [Indexed: 02/03/2023]
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Cui KZ, Liu D, Liu JW, Xu Y, Li YB, Sun YM, Su Y. Role of the Na(+)/Ca(2+) exchanger on the development of diabetes mellitus and its chronic complications. Biochem Biophys Res Commun 2012; 426:445-7. [PMID: 22982318 DOI: 10.1016/j.bbrc.2012.08.130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 08/25/2012] [Indexed: 10/27/2022]
Abstract
Diabetes mellitus (DM) is a serious metabolic disorder with micro- and macrovascular complications that results in significant morbidity and mortality. It is well established that cytosolic Ca(2+) play an important role in controlling insulin secretion in pancreatic β-cells. The Na(+)/Ca(2+) exchanger (NCX), an ion transport protein, is expressed in the plasma membrane of virtually all animal cells. NCX is a reversible carrier that can mediate the transport of Ca(2+) across the plasma membrane in both directions. Therefore, great efforts have been made to identify NCX associated with DM. NCX is expressed in several tissues, and acts in the protection against intracellular calcium overload; in the regulation of insulin secretion by beta cells, and in improving vascular endothelium-dependent relaxation. All these mechanisms are associated with DM pathogenesis and its chronic complications. Therefore, NCX is a candidate protein for the development of these disorders. Only a few studies investigated NCX in relation to chronic complications of diabetes, with inconclusive results.
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Affiliation(s)
- Ke-Zhen Cui
- Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
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Cheng H, Zhang Y, Du C, Dempsey CE, Hancox JC. High potency inhibition of hERG potassium channels by the sodium-calcium exchange inhibitor KB-R7943. Br J Pharmacol 2012; 165:2260-73. [PMID: 21950687 DOI: 10.1111/j.1476-5381.2011.01688.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE KB-R7943 is an isothiourea derivative that is used widely as a pharmacological inhibitor of sodium-calcium exchange (NCX) in experiments on cardiac and other tissue types. This study investigated KB-R7943 inhibition of hERG (human ether-à-go-go-related gene) K(+) channels that underpin the cardiac rapid delayed rectifier potassium current, I(Kr) . EXPERIMENTAL APPROACH Whole-cell patch-clamp measurements were made of hERG current (I(hERG) ) carried by wild-type or mutant hERG channels and of native rabbit ventricular I(Kr) . Docking simulations utilized a hERG homology model built on a MthK-based template. KEY RESULTS KB-R7943 inhibited both I(hERG) and native I(Kr) rapidly on membrane depolarization with IC(50) values of ∼89 and ∼120 nM, respectively, for current tails at -40 mV following depolarizing voltage commands to +20 mV. Marked I(hERG) inhibition also occurred under ventricular action potential voltage clamp. I(hERG) inhibition by KB-R7943 exhibited both time- and voltage-dependence but showed no preference for inactivated over activated channels. Results of alanine mutagenesis and docking simulations indicate that KB-R7943 can bind to a pocket formed of the side chains of aromatic residues Y652 and F656, with the compound's nitrobenzyl group orientated towards the cytoplasmic side of the channel pore. The structurally related NCX inhibitor SN-6 also inhibited I(hERG) , but with a markedly reduced potency. CONCLUSIONS AND IMPLICATIONS KB-R7943 inhibits I(hERG) /I(Kr) with a potency that exceeds that reported previously for acute cardiac NCX inhibition. Our results also support the feasibility of benzyloxyphenyl-containing NCX inhibitors with reduced potential, in comparison with KB-R7943, to inhibit hERG.
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Liao J, Li H, Zeng W, Sauer DB, Belmares R, Jiang Y. Structural insight into the ion-exchange mechanism of the sodium/calcium exchanger. Science 2012; 335:686-690. [PMID: 22323814 DOI: 10.1126/science.1215759] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Sodium/calcium (Na(+)/Ca(2+)) exchangers (NCX) are membrane transporters that play an essential role in maintaining the homeostasis of cytosolic Ca(2+) for cell signaling. We demonstrated the Na(+)/Ca(2+)-exchange function of an NCX from Methanococcus jannaschii (NCX_Mj) and report its 1.9 angstrom crystal structure in an outward-facing conformation. Containing 10 transmembrane helices, the two halves of NCX_Mj share a similar structure with opposite orientation. Four ion-binding sites cluster at the center of the protein: one specific for Ca(2+) and three that likely bind Na(+). Two passageways allow for Na(+) and Ca(2+) access to the central ion-binding sites from the extracellular side. Based on the symmetry of NCX_Mj and its ability to catalyze bidirectional ion-exchange reactions, we propose a structure model for the inward-facing NCX_Mj.
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Affiliation(s)
- Jun Liao
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
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Brittain MK, Brustovetsky T, Sheets PL, Brittain JM, Khanna R, Cummins TR, Brustovetsky N. Delayed calcium dysregulation in neurons requires both the NMDA receptor and the reverse Na+/Ca2+ exchanger. Neurobiol Dis 2012; 46:109-17. [PMID: 22249110 DOI: 10.1016/j.nbd.2011.12.051] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 12/12/2011] [Accepted: 12/31/2011] [Indexed: 12/20/2022] Open
Abstract
Glutamate-induced delayed calcium dysregulation (DCD) is a causal factor leading to neuronal death. The mechanism of DCD is not clear but Ca2+ influx via N-methyl-d-aspartate receptors (NMDAR) and/or the reverse plasmalemmal Na+/Ca2+ exchanger (NCXrev) could be involved in DCD. However, the extent to which NMDAR and NCX(rev) contribute to glutamate-induced DCD is uncertain. Here, we show that both NMDAR and NCX(rev) are critical for DCD in neurons exposed to excitotoxic glutamate. In rat cultured hippocampal neurons, 25 μM glutamate produced DCD accompanied by sustained increase in cytosolic Na+ ([Na+]c) and plasma membrane depolarization. MK801 and memantine, noncompetitive NMDAR inhibitors, added shortly after glutamate, completely prevented DCD whereas AP-5, a competitive NMDAR inhibitor, failed to protect against DCD. None of the tested inhibitors lowered elevated [Na+]c or restored plasma membrane potential. In the experiments with NCX reversal by gramicidin, MK801 and memantine robustly inhibited NCXrev while AP-5 was much less efficacious. In electrophysiological patch-clamp experiments MK801 and memantine inhibited NCXrev-mediated ion currents whereas AP-5 failed. Thus, MK801 and memantine, in addition to NMDAR, inhibited NCXrev. Inhibition of NCXrev either with KB-R7943, or by collapsing Na+ gradient across the plasma membrane, or by inhibiting Na+/H+ exchanger with 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and thus preventing the increase in [Na+]c failed to preclude DCD. However, NCXrev inhibition combined with NMDAR blockade by AP-5 completely prevented DCD. Overall, our data suggest that both NMDAR and NCXrev are essential for DCD in glutamate-exposed neurons and inhibition of individual mechanism is not sufficient to prevent calcium dysregulation.
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Affiliation(s)
- Matthew K Brittain
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Yamakawa T, Watanabe Y, Watanabe H, Kimura J. Inhibitory Effect of Cibenzoline on Na+/Ca2+ Exchange Current in Guinea-Pig Cardiac Ventricular Myocytes. J Pharmacol Sci 2012; 120:59-62. [DOI: 10.1254/jphs.12050sc] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J T Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School ofMedicine, Baltimore, Maryland, USA.
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Andrikopoulos P, Baba A, Matsuda T, Djamgoz MBA, Yaqoob MM, Eccles SA. Ca2+ influx through reverse mode Na+/Ca2+ exchange is critical for vascular endothelial growth factor-mediated extracellular signal-regulated kinase (ERK) 1/2 activation and angiogenic functions of human endothelial cells. J Biol Chem 2011; 286:37919-37931. [PMID: 21873429 PMCID: PMC3207468 DOI: 10.1074/jbc.m111.251777] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 08/25/2011] [Indexed: 11/06/2022] Open
Abstract
VEGF is a key angiogenic cytokine and a major target in anti-angiogenic therapeutic strategies. In endothelial cells (ECs), VEGF binds VEGF receptors and activates ERK1/2 through the phospholipase γ (PLCγ)-PKCα-B-Raf pathway. Our previous work suggested that influx of extracellular Ca(2+) is required for VEGF-induced ERK1/2 activation, and we hypothesized that this could occur through reverse mode (Ca(2+) in and Na(+) out) Na(+)-Ca(2+) exchange (NCX). However, the role of NCX activity in VEGF signaling and angiogenic functions of ECs had not previously been described. Here, using human umbilical vein ECs (HUVECs), we report that extracellular Ca(2+) is required for VEGF-induced ERK1/2 activation and that release of Ca(2+) from intracellular stores alone, in the absence of extracellular Ca(2+), is not sufficient to activate ERK1/2. Furthermore, inhibitors of reverse mode NCX suppressed the VEGF-induced activation of ERK1/2 in a time- and dose-dependent manner and attenuated VEGF-induced Ca(2+) transients. Knockdown of NCX1 (the main NCX isoform in HUVECs) by siRNA confirmed the pharmacological data. A panel of NCX inhibitors also significantly reduced VEGF-induced B-Raf activity and inhibited PKCα translocation to the plasma membrane and total PKC activity in situ. Finally, NCX inhibitors reduced VEGF-induced HUVEC proliferation, migration, and tubular differentiation in surrogate angiogenesis functional assays in vitro. We propose that Ca(2+) influx through reverse mode NCX is required for the activation and the targeting of PKCα to the plasma membrane, an essential step for VEGF-induced ERK1/2 phosphorylation and downstream EC functions in angiogenesis.
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Affiliation(s)
- Petros Andrikopoulos
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, McElwain Laboratories, Cotswold Road, Belmont, Sutton, Surrey SM2 5NG, United Kingdom; Division of Cell and Molecular Biology, Neuroscience Solutions to Cancer Research Group, Imperial College London, London SW7 2AZ, United Kingdom; Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom.
| | - Akemichi Baba
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871
| | - Toshio Matsuda
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871
| | - Mustafa B A Djamgoz
- Division of Cell and Molecular Biology, Neuroscience Solutions to Cancer Research Group, Imperial College London, London SW7 2AZ, United Kingdom
| | - Muhammad M Yaqoob
- Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom
| | - Suzanne A Eccles
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, McElwain Laboratories, Cotswold Road, Belmont, Sutton, Surrey SM2 5NG, United Kingdom.
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Yi T, Wong J, Feller E, Sink S, Taghli-Lamallem O, Wen J, Kim C, Fink M, Giles W, Soussou W, Chen HSV. Electrophysiological mapping of embryonic mouse hearts: mechanisms for developmental pacemaker switch and internodal conduction pathway. J Cardiovasc Electrophysiol 2011; 23:309-18. [PMID: 21985309 DOI: 10.1111/j.1540-8167.2011.02191.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Understanding sinoatrial node (SAN) development could help in developing therapies for SAN dysfunction. However, electrophysiological investigation of SAN development remains difficult because mutant mice with SAN dysfunctions are frequently embryonically lethal. Most research on SAN development is therefore limited to immunocytochemical observations without comparable functional studies. METHODS AND RESULTS We applied a multielectrode array (MEA) recording system to study SAN development in mouse hearts acutely isolated at embryonic ages (E) 8.5-12.5 days. Physiological heart rates were routinely restored, enabling accurate functional assessment of SAN development. We found that dominant pacemaking activity originated from the left inflow tract (LIFT) region at E8.5, but switched to the right SAN by E12.5. Combining MEA recordings and pharmacological agents, we show that intracellular calcium (Ca(2+))-mediated automaticity develops early and is the major mechanism of pulse generation in the LIFT of E8.5 hearts. Later in development at E12.5, sarcolemmal ion channels develop in the SAN at a time when pacemaker channels are down-regulated in the LIFT, leading to a switch in the dominant pacemaker location. Additionally, low micromolar concentrations of tetrodotoxin (TTX), a sodium channel blocker, minimally affect pacemaker rhythm at E8.5-E12.5, but suppress atrial activation and reveal a TTX-resistant SAN-atrioventricular node (internodal) pathway that mediates internodal conduction in E12.5 hearts. CONCLUSIONS Using a physiological mapping method, we demonstrate that differential mechanistic development of automaticity between the left and right inflow tract regions confers the pacemaker location switch. Moreover, a TTX-resistant pathway mediates preferential internodal conduction in E12.5 mouse hearts.
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Affiliation(s)
- Tongyin Yi
- Center for Neuroscience, Aging and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
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Brustovetsky T, Brittain MK, Sheets PL, Cummins TR, Pinelis V, Brustovetsky N. KB-R7943, an inhibitor of the reverse Na+ /Ca2+ exchanger, blocks N-methyl-D-aspartate receptor and inhibits mitochondrial complex I. Br J Pharmacol 2011; 162:255-70. [PMID: 20883473 DOI: 10.1111/j.1476-5381.2010.01054.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE An isothiourea derivative (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methane sulfonate (KB-R7943), a widely used inhibitor of the reverse Na(+) /Ca(2+) exchanger (NCX(rev)), was instrumental in establishing the role of NCX(rev) in glutamate-induced Ca(2+) deregulation in neurons. Here, the effects of KB-R7943 on N-methyl-D-aspartate (NMDA) receptors and mitochondrial complex I were tested. EXPERIMENTAL APPROACH Fluorescence microscopy, electrophysiological patch-clamp techniques and cellular respirometry with Seahorse XF24 analyzer were used with cultured hippocampal neurons; membrane potential imaging, respirometry and Ca(2+) flux measurements were made in isolated rat brain mitochondria. KEY RESULTS KB-R7943 inhibited NCX(rev) with IC(50) = 5.7 ± 2.1 µM, blocked NMDAR-mediated ion currents, and inhibited NMDA-induced increase in cytosolic Ca(2+) with IC(50) = 13.4 ± 3.6 µM but accelerated calcium deregulation and mitochondrial depolarization in glutamate-treated neurons. KB-R7943 depolarized mitochondria in a Ca(2+) -independent manner. Stimulation of NMDA receptors caused NAD(P)H oxidation that was coupled or uncoupled from ATP synthesis depending on the presence of Ca(2+) in the bath solution. KB-R7943, or rotenone, increased NAD(P)H autofluorescence under resting conditions and suppressed NAD(P)H oxidation following glutamate application. KB-R7943 inhibited 2,4-dinitrophenol-stimulated respiration of cultured neurons with IC(50) = 11.4 ± 2.4 µM. With isolated brain mitochondria, KB-R7943 inhibited respiration, depolarized organelles and suppressed Ca(2+) uptake when mitochondria oxidized complex I substrates but was ineffective when mitochondria were supplied with succinate, a complex II substrate. CONCLUSIONS AND IMPLICATIONS KB-R7943, in addition to NCX(rev) , blocked NMDA receptors in cultured hippocampal neurons and inhibited complex I in the mitochondrial respiratory chain. These findings are critical for the correct interpretation of experimental results obtained with KB-R7943 and a better understanding of its neuroprotective action.
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Affiliation(s)
- Tatiana Brustovetsky
- Department of Pharmacology and Toxicology Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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Kim IY, Kang YJ, Yoon MJ, Kim EH, Kim SU, Kwon TK, Kim IA, Choi KS. Amiodarone sensitizes human glioma cells but not astrocytes to TRAIL-induced apoptosis via CHOP-mediated DR5 upregulation. Neuro Oncol 2011; 13:267-79. [PMID: 21292685 DOI: 10.1093/neuonc/noq195] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Amiodarone is a widely used anti-arrhythmic drug that inhibits diverse ion channels, including the Na(+)/Ca(2+) exchanger (NCX), L-type Ca(2+) channels, and Na(+) channels. Here, we report that subtoxic doses of amiodarone and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) synergistically induced apoptosis of various glioma cells. Treatment of U251MG glioma cells with amiodarone increased intracellular Ca(2+) levels and enhanced the expression of the endoplasmic reticulum (ER) stress-inducible transcription factor C/EBP homologous protein (CHOP). This upregulation of CHOP was followed by marked upregulation of the TRAIL receptor, DR5. Suppression of DR5 expression by small interfering (si) RNAs almost completely blocked amiodarone/TRAIL-induced apoptosis in U251MG glioma cells, demonstrating that DR5 is critical to this cell death. siRNA-mediated CHOP suppression reduced amiodarone-induced DR5 upregulation and attenuated the cell death induced by amiodarone plus TRAIL. In addition, omitting Ca(2+) from the external medium using ethylene glycol tetraacetic acid markedly inhibited this cell death, reducing the protein levels of CHOP and DR5. These results suggest that amiodarone-induced influx of Ca(2+) plays an important role in sensitizing U251MG cells to TRAIL-mediated apoptosis through CHOP-mediated DR5 upregulation. Furthermore, subtoxic doses of bepridil and cibenzoline, two other anti-arrhythmic drugs with NCX-inhibitor activity, also sensitized glioma cells to TRAIL-mediated apoptosis, via the upregulation of both CHOP and DR5. Notably, amiodarone/TRAIL cotreatment did not induce cell death in astrocytes, nor did it affect the expression of CHOP or DR5 in these cells. These results collectively suggest that a combined regimen of amiodarone plus TRAIL may offer an effective therapeutic strategy for safely and selectively treating resistant gliomas.
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Affiliation(s)
- In Young Kim
- Department of Molecular Science & Technology Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-749, Korea
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Oda T, Kume T, Izumi Y, Ishihara K, Sugmimoto H, Akaike A. Na+/Ca2+ Exchanger Inhibitors Inhibit Neurite Outgrowth in PC12 Cells. J Pharmacol Sci 2011; 116:128-31. [DOI: 10.1254/jphs.11011sc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Kim C, Majdi M, Xia P, Wei KA, Talantova M, Spiering S, Nelson B, Mercola M, Chen HSV. Non-cardiomyocytes influence the electrophysiological maturation of human embryonic stem cell-derived cardiomyocytes during differentiation. Stem Cells Dev 2010; 19:783-95. [PMID: 20001453 DOI: 10.1089/scd.2009.0349] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Various types of cardiomyocytes undergo changes in automaticity and electrical properties during fetal heart development. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs), like fetal cardiomyocytes, are electrophysiologically immature and exhibit automaticity. We used hESC-CMs to investigate developmental changes in mechanisms of automaticity and to determine whether electrophysiological maturation is driven by an intrinsic developmental clock and/or is regulated by interactions with non-cardiomyocytes in embryoid bodies (EBs). We isolated pure populations of hESC-CMs from EBs by lentivirus-engineered Puromycin resistance at various stages of differentiation. Using pharmacological agents, calcium (Ca(2+)) imaging, and intracellular recording techniques, we found that intracellular Ca(2+)-cycling mechanisms developed early and contributed to dominant automaticity throughout hESC-CM differentiation. Sarcolemmal ion channels evolved later upon further differentiation within EBs and played an increasing role in controlling automaticity and electrophysiological properties of hESC-CMs. In contrast to the development of intracellular Ca(2+)-handling proteins, ion channel development and electrophysiological maturation of hESC-CMs did not occur when hESC-CMs were isolated from EBs early and maintained in culture without further interaction with non-cardiomyocytes. Adding back non-cardiomyocytes to early-isolated hESC-CMs rescued the arrest of electrophysiological maturation, indicating that non-cardiomyocytes in EBs drive electrophysiological maturation of early hESC-CMs. Non-cardiomyocytes in EBs contain most cell types present in the embryonic heart that are known to influence early cardiac development. Our study is the first to demonstrate that non-cardiomyocytes influence electrophysiological maturation of early hESC-CMs in cultures. Defining the nature of these extrinsic signals will aid in the directed maturation of immature hESC-CMs to mitigate arrhythmogenic risks of cell-based therapies.
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Affiliation(s)
- Changsung Kim
- Center for Neuroscience, Aging and Stem Cell Research, Burnham Institute for Medical Research, La Jolla, California 92037, USA
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Watanabe Y, Kimura J. Inhibitory effect of azimilide on Na+/Ca2+ exchange current in guinea-pig cardiac myocytes. J Pharmacol Sci 2010; 114:111-4. [PMID: 20710119 DOI: 10.1254/jphs.10066sc] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
We examined the effect of azimilide, a class III antiarrhythmic drug, on Na(+)/Ca(2+) exchange current (I(NCX)) in guinea-pig cardiac single ventricular cells. External application of azimilide suppressed bi-directional I(NCX) in a concentration-dependent manner. IC(50) values for outward and inward I(NCX) were 45 and 40 µM, respectively, with Hill coefficients of 1. Azimilide attenuated I(NCX) in the presence of trypsin in the patch pipette, indicating that azimilide is a trypsin-insensitive NCX inhibitor. Delayed afterdepolarization induced by electrical stimulation with ouabain disappeared in the presence of 30 µM azimilide. We conclude that azimilide inhibits NCX at supratherapeutic concentrations.
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Affiliation(s)
- Yasuhide Watanabe
- Division of Pharmacological Science, Department of Health Science, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, Japan.
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Bonazzola P, Takara D. Cardiac basal metabolism: energetic cost of calcium withdrawal in the adult rat heart. Acta Physiol (Oxf) 2010; 199:293-304. [PMID: 20132146 DOI: 10.1111/j.1748-1716.2010.02094.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Cardiac basal metabolism upon extracellular calcium removal and its relationship with intracellular sodium and calcium homeostasis was evaluated. METHODS A mechano-calorimetric technique was used that allowed the simultaneous and continuous measurement of both heat rate and resting pressure in arterially perfused quiescent adult rat hearts. Using pharmacological tools, the possible underlying mechanisms related to sodium and calcium movements were investigated. RESULTS Resting heat rate (expressed in mW g(-1)(dry wt)) increased upon calcium withdrawal (+4.4 +/- 0.2). This response was: (1) unaffected by the presence of tetrodotoxin (+4.3 +/- 0.6), (2) fully blocked by both, the decrease in extracellular sodium concentration and the increase in extracellular magnesium concentration, (3) partially blocked by the presence of either nifedipine (+2.8 +/- 0.4), KB-R7943 (KBR; +2.5 +/- 0.2), clonazepam (CLO; +3.1 +/- 0.3) or EGTA (+1.9 +/- 0.3). The steady heat rate under Ca(2+)-free conditions was partially reduced by the addition of Ru360 (-1.1 +/- 0.2) but not CLO in the presence of EGTA, KBR or Ru360. CONCLUSION Energy expenditure for resting state maintenance upon calcium withdrawal depends on the intracellular rise in both sodium and calcium. Our data are consistent with a mitochondrial Ca(2+) cycling, not detectable under normal calcium diastolic levels. The experimental condition here analysed, partially simulates findings reported under certain pathological situations including heart failure in which mildly increased levels of both diastolic sodium and calcium have also been found. Therefore, under such pathological conditions, hearts should distract chemical energy to fuel processes associated with sodium and calcium handling, making more expensive the maintenance of their functions.
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46
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Rotmann A, Sanchez C, Guiguemde A, Rohrbach P, Dave A, Bakouh N, Planelles G, Lanzer M. PfCHA is a mitochondrial divalent cation/H+ antiporter in Plasmodium falciparum. Mol Microbiol 2010; 76:1591-606. [PMID: 20487273 DOI: 10.1111/j.1365-2958.2010.07187.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human malaria parasite Plasmodium falciparum is capable of adapting to vastly different extracellular Ca(2+) environments while maintaining tight control of its intracellular Ca(2+) concentration. The mechanisms underpinning Ca(2+) homeostasis in this important pathogen are only partly understood. Here we have functionally expressed the putative Ca(2+)/H(+) antiporter PfCHA in Xenopus laevis oocytes. Our data suggest that PfCHA mediates H(+)-coupled Ca(2+) and Mn(2+) exchange. The apparent dissociation constant K(M) for Ca(2+) of 2.2 +/- 0.7 mM and the maximal velocity V(max) of 0.6 +/- 0.1 nmol per oocyte per hour are consistent with PfCHA being a low-affinity high-capacity Ca(2+) carrier. In the parasite, PfCHA was found to localize to the mitochondrion. Physiological studies conducted with live parasitized erythrocytes, and using Fluo-4 and Rhod-2 to monitor cytoplasmic and mitochondrial Ca(2+) dynamics, suggest that the mitochondrion serves as a dynamic Ca(2+) store and that PfCHA functions as a Ca(2+) efflux system expelling excess Ca(2+) from the mitochondrion. PfCHA lacks appreciable homologies to the human mitochondrial Ca(2+)/H(+) exchanger and might represent an evolutionary divergent class of mitochondrial cation antiporter, which, in turn, might provide novel opportunities for intervention.
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Affiliation(s)
- Alexander Rotmann
- Hygiene Institut, Abteilung Parasitologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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Kaur G, Jaggi AS, Singh N. Ameliorative Potential of Pralidoxime in Tibial and Sural Nerve Transection-Induced Neuropathic Pain in Rats. Biol Pharm Bull 2010; 33:1331-6. [DOI: 10.1248/bpb.33.1331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Gurpreet Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University
| | | | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University
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Storozhevykh TP, Senilova YE, Brustovetsky T, Pinelis VG, Brustovetsky N. Neuroprotective Effect of KB-R7943 Against Glutamate Excitotoxicity is Related to Mild Mitochondrial Depolarization. Neurochem Res 2009; 35:323-35. [DOI: 10.1007/s11064-009-0058-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2009] [Indexed: 01/08/2023]
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Laskowski AI, Medler KF. Sodium-calcium exchangers contribute to the regulation of cytosolic calcium levels in mouse taste cells. J Physiol 2009; 587:4077-89. [PMID: 19581381 DOI: 10.1113/jphysiol.2009.173567] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Taste cells use multiple signalling mechanisms to generate unique calcium responses to distinct taste stimuli. Some taste stimuli activate G-protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). We recently demonstrated that a constitutive calcium influx exists in taste cells that is regulated by mitochondrial calcium transport and that the magnitude of this calcium influx correlates with the signalling mechanisms used by the taste cells. In this study, we used calcium imaging to determine that sodium-calcium exchangers (NCXs) also routinely contribute to the regulation of basal cytosolic calcium and that their relative role correlates with the signalling mechanisms used by the taste cells. RT-PCR analysis revealed that multiple NCXs and sodium-calcium-potassium exchangers (NCKXs) are expressed in taste cells. Thus, a dynamic relationship exists between calcium leak channels and calcium regulatory mechanisms in taste cells that functions to keep cytosolic calcium levels in the appropriate range for cell function.
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Affiliation(s)
- Agnieszka I Laskowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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Peña A, Calahorra M, Michel B, Ramírez J, Sánchez NS. Effects of amiodarone on K+, internal pH and Ca2+ homeostasis in Saccharomyces cerevisiae. FEMS Yeast Res 2009; 9:832-48. [PMID: 19656199 DOI: 10.1111/j.1567-1364.2009.00538.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
In this study, amiodarone, at very low concentrations, produced a clear efflux of K(+). Increasing concentrations also produced an influx of protons, resulting in an increase of the external pH and a decrease of the internal pH. The K(+) efflux resulted in an increased plasma membrane potential difference, responsible for the entrance of Ca(2+) and H(+), the efflux of anions and the subsequent changes resulting from the increased cytoplasmic Ca(2+) concentration, as well as the decreased internal pH. The Deltatok1 and Deltanha1 mutations resulted in a smaller effect of amiodarone, and Deltatrk1 and Deltatrk2 showed a higher increase of the plasma membrane potential. Higher concentrations of amiodarone also produced full inhibition of respiration, insensitive to uncouplers and a partial inhibition of fermentation. This phenomenon appears to be common to a large series of cationic molecules that can produce the efflux of K(+), through the reduction of the negative surface charge of the cell membrane, and the concentration of this cation directly available to the monovalent cation carriers, and/or producing a disorganization of the membrane and altering the functioning of the carriers, probably not only in yeast.
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Affiliation(s)
- Antonio Peña
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, D.F., Mexico.
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