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Sáez JC, Contreras-Duarte S, Labra VC, Santibañez CA, Mellado LA, Inostroza CA, Alvear TF, Retamal MA, Velarde V, Orellana JA. Interferon-γ and high glucose-induced opening of Cx43 hemichannels causes endothelial cell dysfunction and damage. Biochim Biophys Acta Mol Cell Res 2020; 1867:118720. [PMID: 32302669 DOI: 10.1016/j.bbamcr.2020.118720] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 12/17/2022]
Abstract
Both IFN-γ or high glucose have been linked to systemic inflammatory imbalance with serious repercussions not only for endothelial function but also for the formation of the atherosclerotic plaque. Although the uncontrolled opening of connexin hemichannels underpins the progression of various diseases, whether they are implicated in endothelial cell dysfunction and damage evoked by IFN-γ plus high glucose remains to be fully elucidated. In this study, by using live cell imaging and biochemical approaches, we demonstrate that IFN-γ plus high glucose augment endothelial connexin43 hemichannel activity, resulting in the increase of ATP release, ATP-mediated Ca2+ dynamics and production of nitric oxide and superoxide anion, as well as impaired insulin-mediated uptake and intercellular diffusion of glucose and cell survival. Based on our results, we propose that connexin 43 hemichannel inhibition could serve as a new approach for tackling the activation of detrimental signaling resulting in endothelial cell dysfunction and death caused by inflammatory mediators during atherosclerosis secondary to diabetes mellitus.
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Turovsky EA, Zinchenko VP, Kaimachnikov NP. Attenuation of calmodulin regulation evokes Ca 2+ oscillations: evidence for the involvement of intracellular arachidonate-activated channels and connexons. Mol Cell Biochem 2019; 456:191-204. [PMID: 30756222 DOI: 10.1007/s11010-019-03504-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 02/01/2019] [Indexed: 01/02/2023]
Abstract
Intracellular Са2+ controls its own level by regulation of Ca2+ transport across the plasma and organellar membranes, often acting via calmodulin (CaM). Drugs antagonizing CaM action induce an increase in cytosolic Ca2+ concentration in different cells. We have found persistent Са2+ oscillations in cultured white adipocytes in response to calmidazolium (CMZ). They appeared at [CMZ] > 1 μM as repetitive sharp spikes mainly superimposed on a transient or elevated baseline. Similar oscillations were observed when we used trifluoperazine. Oscillations evoked by 5 μM CMZ resulted from the release of stored Ca2+ and were supported by Са2+ entry. Inhibition of store-operated channels by YM-58483 or 2-APB did not change the responses. Phospholipase A2 inhibited by AACOCF3 was responsible for initial Ca2+ mobilization, but not for subsequent oscillations, whereas inhibition of iPLA2 by BEL had no effect. Phospholipase C was partially involved in both stages as revealed with U73122. Intracellular Са2+ stores engaged by CMZ were entirely dependent on thapsigargin. The oscillations existed in the presence of inhibitors of ryanodine or inositol 1,4,5-trisphosphate receptors, or antagonists of Ca2+ transport by lysosome-like acidic stores. Carbenoxolone or octanol, blockers of hemichannels (connexons), when applied for two hours, prevented oscillations but did not affect the initial Са2+ release. Incubation with La3+ for 2 or 24 h inhibited all responses to CMZ, retaining the thapsigargin-induced Ca2+ rise. These results suggest that Ca2+-CaM regulation suppresses La3+-sensitive channels in non-acidic organelles, of which arachidonate-activated channels initiate Ca2+ oscillations, and connexons are intimately implicated in their generation mechanism.
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Affiliation(s)
- Egor A Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
| | - Valery P Zinchenko
- Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290
| | - Nikolai P Kaimachnikov
- Institute of Cell Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia, 142290.
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Becker D, Minor KM, Letko A, Ekenstedt KJ, Jagannathan V, Leeb T, Shelton GD, Mickelson JR, Drögemüller C. A GJA9 frameshift variant is associated with polyneuropathy in Leonberger dogs. BMC Genomics 2017; 18:662. [PMID: 28841859 PMCID: PMC5574090 DOI: 10.1186/s12864-017-4081-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 08/21/2017] [Indexed: 01/15/2023] Open
Abstract
Background Many inherited polyneuropathies (PN) observed in dogs have clinical similarities to the genetically heterogeneous group of Charcot-Marie-Tooth (CMT) peripheral neuropathies in humans. The canine disorders collectively show a variable expression of progressive clinical signs and ages of onset, and different breed prevalences. Previously in the Leonberger breed, a variant highly associated with a juvenile-onset PN was identified in the canine orthologue of a CMT-associated gene. As this deletion in ARHGEF10 (termed LPN1) does not explain all cases, PN in this breed may encompass variants in several genes with similar clinical and histopathological features. Results A genome-wide comparison of 173 k SNP genotypes of 176 cases, excluding dogs homozygous for the ARHGEF10 variant, and 138 controls, was carried out to detect further PN-associated variants. A single suggestive significant association signal on CFA15 was found. The genome of a PN-affected Leonberger homozygous for the associated haplotype was sequenced and variants in the 7.7 Mb sized critical interval were identified. These variants were filtered against a database of variants observed in 202 genomes of various dog breeds and 3 wolves, and 6 private variants in protein-coding genes, all in complete linkage disequilibrium, plus 92 non-coding variants were revealed. Five of the coding variants were predicted to have low or moderate effect on the encoded protein, whereas a 2 bp deletion in GJA9 results in a frameshift of high impact. GJA9 encodes connexin 59, a connexin gap junction family protein, and belongs to a group of CMT-associated genes that have emerged as important components of peripheral myelinated nerve fibers. The association between the GJA9 variant and PN was confirmed in an independent cohort of 296 cases and 312 controls. Population studies showed a dominant mode of inheritance, an average age of onset of approximately 6 years, and incomplete penetrance. Conclusions This GJA9 variant represents a highly probable candidate variant for another form of PN in Leonberger dogs, which we have designated LPN2, and a new candidate gene for CMT disease. To date, approximately every third PN-diagnosed Leonberger dog can be explained by the ARHGEF10 or GJA9 variants, and we assume that additional genetic heterogeneity in this condition exists in the breed. Electronic supplementary material The online version of this article (10.1186/s12864-017-4081-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Doreen Becker
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - Katie M Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Anna Letko
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - Kari J Ekenstedt
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.,Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, California, 92093, USA
| | - James R Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland.
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Cea LA, Balboa E, Puebla C, Vargas AA, Cisterna BA, Escamilla R, Regueira T, Sáez JC. Dexamethasone-induced muscular atrophy is mediated by functional expression of connexin-based hemichannels. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1891-9. [PMID: 27437607 DOI: 10.1016/j.bbadis.2016.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/29/2016] [Accepted: 07/12/2016] [Indexed: 11/29/2022]
Abstract
Long-term treatment with high glucocorticoid doses induces skeletal muscle atrophy. However, the molecular mechanism of such atrophy remains unclear. We evaluated the possible involvement of connexin-based hemichannels (Cx HCs) in muscle atrophy induced by dexamethasone (DEX), a synthetic glucocorticoid, on control (Cx43(fl/fl)Cx45(fl/fl)) and Cx43/Cx45 expression-deficient (Cx43(fl/fl)Cx45(fl/fl):Myo-Cre) skeletal myofibers. Myofibers of Cx43(fl/fl)Cx45(fl/fl) mice treated with DEX (5h) expressed several proteins that form non-selective membrane channels (Cx39, Cx43, Cx45, Panx1, P2X7 receptor and TRPV2). After 5h DEX treatment in vivo, myofibers of Cx43(fl/fl)Cx45(fl/fl) mice showed Evans blue uptake, which was absent in myofibers of Cx43(fl/fl)Cx45(fl/fl):Myo-Cre mice. Similar results were obtained in vitro using ethidium as an HC permeability probe, and DEX-induced dye uptake in control myofibers was blocked by P2X7 receptor inhibitors. DEX also induced a significant increase in basal intracellular Ca(2+) signal and a reduction in resting membrane potential in Cx43(fl/fl)Cx45(fl/fl) myofibers, changes that were not elicited by myofibers deficient in Cx43/Cx45 expression. Moreover, treatment with DEX induced NFκB activation and increased mRNA levels of TNF-α in control but not in Cx43/Cx45 expression-deficient myofibers. Finally, a prolonged DEX treatment (7days) increased atrogin-1 and Murf-1 and reduced the cross sectional area of Cx43(fl/fl)Cx45(fl/fl) myofibers, but these parameters remained unaffected in Cx43(fl/fl)Cx45(fl/fl):Myo-Cre myofibers. Therefore, DEX-induced expression of Cx43 and Cx45 plays a critical role in early sarcolemma changes that lead to atrophy. Consequently, this side effect of chronic glucocorticoid treatment might be avoided by co-administration with a Cx HC blocker.
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Affiliation(s)
- Luis A Cea
- Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.
| | - Elisa Balboa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Departamento Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Aníbal A Vargas
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Bruno A Cisterna
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Rosalba Escamilla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Tomás Regueira
- Departamento Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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Cea LA, Puebla C, Cisterna BA, Escamilla R, Vargas AA, Frank M, Martínez-Montero P, Prior C, Molano J, Esteban-Rodríguez I, Pascual I, Gallano P, Lorenzo G, Pian H, Barrio LC, Willecke K, Sáez JC. Fast skeletal myofibers of mdx mouse, model of Duchenne muscular dystrophy, express connexin hemichannels that lead to apoptosis. Cell Mol Life Sci 2016; 73:2583-99. [PMID: 26803842 DOI: 10.1007/s00018-016-2132-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/15/2015] [Accepted: 01/07/2016] [Indexed: 02/07/2023]
Abstract
Skeletal muscles of patients with Duchenne muscular dystrophy (DMD) show numerous alterations including inflammation, apoptosis, and necrosis of myofibers. However, the molecular mechanism that explains these changes remains largely unknown. Here, the involvement of hemichannels formed by connexins (Cx HCs) was evaluated in skeletal muscle of mdx mouse model of DMD. Fast myofibers of mdx mice were found to express three connexins (39, 43 and 45) and high sarcolemma permeability, which was absent in myofibers of mdx Cx43(fl/fl)Cx45(fl/fl):Myo-Cre mice (deficient in skeletal muscle Cx43/Cx45 expression). These myofibers did not show elevated basal intracellular free Ca(2+) levels, immunoreactivity to phosphorylated p65 (active NF-κB), eNOS and annexin V/active Caspase 3 (marker of apoptosis) but presented dystrophin immunoreactivity. Moreover, muscles of mdx Cx43(fl/fl)Cx45(fl/fl):Myo-Cre mice exhibited partial decrease of necrotic features (big cells and high creatine kinase levels). Accordingly, these muscles showed similar macrophage infiltration as control mdx muscles. Nonetheless, the hanging test performance of mdx Cx43(fl/fl)Cx45(fl/fl):Myo-Cre mice was significantly better than that of control mdx Cx43(fl/fl)Cx45(fl/fl) mice. All three Cxs found in skeletal muscles of mdx mice were also detected in fast myofibers of biopsy specimens from patients with muscular dystrophy. Thus, reduction of Cx expression and/or function of Cx HCs may be potential therapeutic approaches to abrogate myofiber apoptosis in DMD.
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Affiliation(s)
- Luis A Cea
- Present: Program of Anatomy and Developmental Biology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile. .,Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile.
| | - Carlos Puebla
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Bruno A Cisterna
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Rosalba Escamilla
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile.,Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile
| | - Aníbal A Vargas
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Marina Frank
- Division of Molecular Genetics, Life and Medical Sciences Institute, University of Bonn, 53115, Bonn, Germany
| | | | - Carmen Prior
- Unidad de Genética Molecular-INGEMM, Hospital Universitario La Paz-IdIPAZ, Madrid, Spain
| | - Jesús Molano
- Unidad de Genética Molecular-INGEMM, Hospital Universitario La Paz-IdIPAZ, Madrid, Spain
| | | | - Ignacio Pascual
- Servicio de Neuropediatría, Hospital Universitario La Paz-IdIPAZ, Madrid, Spain
| | - Pía Gallano
- Servicio de Genética, Hospital Santa Creu i Sant Pablo-CIBERER, Barcelona, Spain
| | - Gustavo Lorenzo
- Servicio de Pediatria, "Ramón y Cajal" Hospital-IRYCIS, Madrid, Spain
| | - Héctor Pian
- Servicio de Anatomía Patológica, "Ramón y Cajal" Hospital-IRYCIS, Madrid, Spain
| | - Luis C Barrio
- Unidad de Neurología Experimental, "Ramón y Cajal" Hospital-IRYCIS, Madrid, Spain
| | - Klaus Willecke
- Division of Molecular Genetics, Life and Medical Sciences Institute, University of Bonn, 53115, Bonn, Germany
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile. .,Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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