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Bayraktar E, Lopez-Pigozzi D, Bortolozzi M. Calcium Regulation of Connexin Hemichannels. Int J Mol Sci 2024; 25:6594. [PMID: 38928300 PMCID: PMC11204158 DOI: 10.3390/ijms25126594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/07/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Connexin hemichannels (HCs) expressed at the plasma membrane of mammalian cells are of paramount importance for intercellular communication. In physiological conditions, HCs can form gap junction (GJ) channels, providing a direct diffusive path between neighbouring cells. In addition, unpaired HCs provide conduits for the exchange of solutes between the cytoplasm and the extracellular milieu, including messenger molecules involved in paracrine signalling. The synergistic action of membrane potential and Ca2+ ions controls the gating of the large and relatively unselective pore of connexin HCs. The four orders of magnitude difference in gating sensitivity to the extracellular ([Ca2+]e) and the cytosolic ([Ca2+]c) Ca2+ concentrations suggests that at least two different Ca2+ sensors may exist. While [Ca2+]e acts as a spatial modulator of the HC opening, which is most likely dependent on the cell layer, compartment, and organ, [Ca2+]c triggers HC opening and the release of extracellular bursts of messenger molecules. Such molecules include ATP, cAMP, glutamate, NAD+, glutathione, D-serine, and prostaglandins. Lost or abnormal HC regulation by Ca2+ has been associated with several diseases, including deafness, keratitis ichthyosis, palmoplantar keratoderma, Charcot-Marie-Tooth neuropathy, oculodentodigital dysplasia, and congenital cataracts. The fact that both an increased and a decreased Ca2+ sensitivity has been linked to pathological conditions suggests that Ca2+ in healthy cells finely tunes the normal HC function. Overall, further investigation is needed to clarify the structural and chemical modifications of connexin HCs during [Ca2+]e and [Ca2+]c variations. A molecular model that accounts for changes in both Ca2+ and the transmembrane voltage will undoubtedly enhance our interpretation of the experimental results and pave the way for developing therapeutic compounds targeting specific HC dysfunctions.
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Affiliation(s)
- Erva Bayraktar
- Veneto Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Via Marzolo 8, 35131 Padova, Italy
| | - Diego Lopez-Pigozzi
- Veneto Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Via Marzolo 8, 35131 Padova, Italy
| | - Mario Bortolozzi
- Veneto Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Via Marzolo 8, 35131 Padova, Italy
- Institute of Endocrinology and Oncology “Gaetano Salvatore” (IEOS-CNR), Via Pietro Castellino 111, 80131 Napoli, Italy
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2
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Gómez GI, Alvear TF, Roa DA, Farias-Pasten A, Vergara SA, Mellado LA, Martinez-Araya CJ, Prieto-Villalobos J, García-Rodríguez C, Sánchez N, Sáez JC, Ortíz FC, Orellana JA. Cx43 hemichannels and panx1 channels contribute to ethanol-induced astrocyte dysfunction and damage. Biol Res 2024; 57:15. [PMID: 38576018 PMCID: PMC10996276 DOI: 10.1186/s40659-024-00493-2] [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: 12/23/2023] [Accepted: 03/25/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Alcohol, a widely abused drug, significantly diminishes life quality, causing chronic diseases and psychiatric issues, with severe health, societal, and economic repercussions. Previously, we demonstrated that non-voluntary alcohol consumption increases the opening of Cx43 hemichannels and Panx1 channels in astrocytes from adolescent rats. However, whether ethanol directly affects astroglial hemichannels and, if so, how this impacts the function and survival of astrocytes remains to be elucidated. RESULTS Clinically relevant concentrations of ethanol boost the opening of Cx43 hemichannels and Panx1 channels in mouse cortical astrocytes, resulting in the release of ATP and glutamate. The activation of these large-pore channels is dependent on Toll-like receptor 4, P2X7 receptors, IL-1β and TNF-α signaling, p38 mitogen-activated protein kinase, and inducible nitric oxide (NO) synthase. Notably, the ethanol-induced opening of Cx43 hemichannels and Panx1 channels leads to alterations in cytokine secretion, NO production, gliotransmitter release, and astrocyte reactivity, ultimately impacting survival. CONCLUSION Our study reveals a new mechanism by which ethanol impairs astrocyte function, involving the sequential stimulation of inflammatory pathways that further increase the opening of Cx43 hemichannels and Panx1 channels. We hypothesize that targeting astroglial hemichannels could be a promising pharmacological approach to preserve astrocyte function and synaptic plasticity during the progression of various alcohol use disorders.
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Affiliation(s)
- Gonzalo I Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Tanhia F Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Daniela A Roa
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Arantza Farias-Pasten
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Sergio A Vergara
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Luis A Mellado
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Claudio J Martinez-Araya
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Claudia García-Rodríguez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, 2360102, Chile
| | - Natalia Sánchez
- Department of Anatomy, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan C Sáez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, 2360102, Chile
| | - Fernando C Ortíz
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Mechanisms of Myelin Formation and Repair Laboratory, Chacabuco 675, of. 212, Santiago, 8350347, Chile.
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile.
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3
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Carvalho TP, Toledo FAO, Bautista DFA, Silva MF, Oliveira JBS, Lima PA, Costa FB, Ribeiro NQ, Lee JY, Birbrair A, Paixão TA, Tsolis RM, Santos RL. Pericytes modulate endothelial inflammatory response during bacterial infection. mBio 2024; 15:e0325223. [PMID: 38289074 PMCID: PMC10936204 DOI: 10.1128/mbio.03252-23] [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: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 03/14/2024] Open
Abstract
Pericytes are located around blood vessels, in close contact with endothelial cells. We discovered that pericytes dampen pro-inflammatory endothelial cell responses. Endothelial cells co-cultured with pericytes had markedly reduced expression of adhesion molecules (PECAM-1 and ICAM-1) and proinflammatory cytokines (CCL-2 and IL-6) in response to bacterial stimuli (Brucella ovis, Listeria monocytogenes, or Escherichia coli lipopolysaccharide). Pericyte-depleted mice intraperitoneally inoculated with either B. ovis, a stealthy pathogen that does not trigger detectable inflammation, or Listeria monocytogenes, developed peritonitis. Further, during Citrobacter rodentium infection, pericyte-depleted mice developed severe intestinal inflammation, which was not evident in control mice. The anti-inflammatory effect of pericytes required connexin 43, as either chemical inhibition or silencing of connexin 43 abrogated pericyte-mediated suppression of endothelial inflammatory responses. Our results define a mechanism by which pericytes modulate inflammation during infection, which shifts our understanding of pericyte biology: from a structural cell to a pro-active player in modulating inflammation. IMPORTANCE A previously unknown mechanism by which pericytes modulate inflammation was discovered. The absence of pericytes or blocking interaction between pericytes and endothelium through connexin 43 results in stronger inflammation, which shifts our understanding of pericyte biology, from a structural cell to a player in controlling inflammation.
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Affiliation(s)
- Thaynara P. Carvalho
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Medical Microbiology and Immunology, University of California, Davis, California, USA
| | - Frank A. O. Toledo
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Diego F. A. Bautista
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Monique F. Silva
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Jefferson B. S. Oliveira
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pâmela A. Lima
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fabíola B. Costa
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Noelly Q. Ribeiro
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Jee-Yon Lee
- Department of Medical Microbiology and Immunology, University of California, Davis, California, USA
| | - Alexander Birbrair
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tatiane A. Paixão
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Reneé M. Tsolis
- Department of Medical Microbiology and Immunology, University of California, Davis, California, USA
| | - Renato L. Santos
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Medical Microbiology and Immunology, University of California, Davis, California, USA
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Prieto-Villalobos J, Lucero CM, Rovegno M, Gómez GI, Retamal MA, Orellana JA. SARS-CoV-2 spike protein S1 activates Cx43 hemichannels and disturbs intracellular Ca 2+ dynamics. Biol Res 2023; 56:56. [PMID: 37876016 PMCID: PMC10598968 DOI: 10.1186/s40659-023-00468-9] [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: 06/14/2023] [Accepted: 10/12/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the ongoing coronavirus disease 2019 (COVID-19). An aspect of high uncertainty is whether the SARS-CoV-2 per se or the systemic inflammation induced by viral infection directly affects cellular function and survival in different tissues. It has been postulated that tissue dysfunction and damage observed in COVID-19 patients may rely on the direct effects of SARS-CoV-2 viral proteins. Previous evidence indicates that the human immunodeficiency virus and its envelope protein gp120 increase the activity of connexin 43 (Cx43) hemichannels with negative repercussions for cellular function and survival. Here, we evaluated whether the spike protein S1 of SARS-CoV-2 could impact the activity of Cx43 hemichannels. RESULTS We found that spike S1 time and dose-dependently increased the activity of Cx43 hemichannels in HeLa-Cx43 cells, as measured by dye uptake experiments. These responses were potentiated when the angiotensin-converting enzyme 2 (ACE2) was expressed in HeLa-Cx43 cells. Patch clamp experiments revealed that spike S1 increased unitary current events with conductances compatible with Cx43 hemichannels. In addition, Cx43 hemichannel opening evoked by spike S1 triggered the release of ATP and increased the [Ca2+]i dynamics elicited by ATP. CONCLUSIONS We hypothesize that Cx43 hemichannels could represent potential pharmacological targets for developing therapies to counteract SARS-CoV-2 infection and their long-term consequences.
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Affiliation(s)
- Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Claudia M Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Mauricio A Retamal
- Programa de Comunicación Celular en Cancer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
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5
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Xu C, Zhong W, Zhang H, Jiang J, Zhou H. Gap26 inhibited angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway. Life Sci 2023:121836. [PMID: 37295713 DOI: 10.1016/j.lfs.2023.121836] [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: 04/18/2023] [Revised: 05/22/2023] [Accepted: 06/04/2023] [Indexed: 06/12/2023]
Abstract
PURPOSE To investigate the effect of connexin 43 (Cx43) on corneal neovascularization and its regulation of VEGFR2 on vascular endothelial cells. METHODS In vivo, we used mouse corneal suture model to induce corneal neovascularization and discovered the function of gap26 in corneal neovascularization. In vitro, the effect of gap26 on HUVEC was observed by cell proliferation, tube formation and scratch experiments. WB and PCR detected the changes in angiogenic protein and mRNA expression. Knockdown of key mRNA in neovascularization using siRNA confirmed that Cx43 regulates neovascularization through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway. RESULTS In vivo, gap26 can reduce mouse corneal neovascularization. In vitro, we show that Cx43 expression is increased in the presence of VEGFA stimulation, and when we use gap26 to inhibit Cx43 can reduce vascular endothelial cell proliferation, tube formation and migration. We found that the expression of pVEGFR2 and pErk increased in response to VEGFA, while they decreased after using gap26. And the expression of β-catenin and VE-cadherin decreased in response to VEGFA, while they increased after using gap26. Furthermore, we found that Cx43 regulates angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk pathway. CONCLUSIONS Gap26 can downregulate VEGFR2 phosphorylation by stabilizing the expression of β-catenin and VE-cadherin on the cell membrane, thereby inhibiting VEGFA-induced HUVECs proliferation, migration and tube formation and inhibiting corneal neovascularization.
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Affiliation(s)
- Chuyang Xu
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Wei Zhong
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Hong Zhang
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Jinlan Jiang
- Scientific Research Center, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China.
| | - Hongyan Zhou
- Department of Ophthalmology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China.
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Leybaert L, De Smet MA, Lissoni A, Allewaert R, Roderick HL, Bultynck G, Delmar M, Sipido KR, Witschas K. Connexin hemichannels as candidate targets for cardioprotective and anti-arrhythmic treatments. J Clin Invest 2023; 133:168117. [PMID: 36919695 PMCID: PMC10014111 DOI: 10.1172/jci168117] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023] Open
Abstract
Connexins are crucial cardiac proteins that form hemichannels and gap junctions. Gap junctions are responsible for the propagation of electrical and chemical signals between myocardial cells and cells of the specialized conduction system in order to synchronize the cardiac cycle and steer cardiac pump function. Gap junctions are normally open, while hemichannels are closed, but pathological circumstances may close gap junctions and open hemichannels, thereby perturbing cardiac function and homeostasis. Current evidence demonstrates an emerging role of hemichannels in myocardial ischemia and arrhythmia, and tools are now available to selectively inhibit hemichannels without inhibiting gap junctions as well as to stimulate hemichannel incorporation into gap junctions. We review available experimental evidence for hemichannel contributions to cellular pro-arrhythmic events in ventricular and atrial cardiomyocytes, and link these to insights at the level of molecular control of connexin-43-based hemichannel opening. We conclude that a double-edged approach of both preventing hemichannel opening and preserving gap junctional function will be key for further research and development of new connexin-based experimental approaches for treating heart disease.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Maarten Aj De Smet
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Alessio Lissoni
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Rosalie Allewaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mario Delmar
- Leon H. Charney Division of Cardiology, School of Medicine, New York University, New York, USA
| | - Karin R Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Katja Witschas
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
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7
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Kiełbowski K, Bakinowska E, Pawlik A. The Potential Role of Connexins in the Pathogenesis of Atherosclerosis. Int J Mol Sci 2023; 24:ijms24032600. [PMID: 36768920 PMCID: PMC9916887 DOI: 10.3390/ijms24032600] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/29/2022] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Connexins (Cx) are members of a protein family which enable extracellular and intercellular communication through hemichannels and gap junctions (GJ), respectively. Cx take part in transporting important cell-cell messengers such as 3',5'-cyclic adenosine monophosphate (cAMP), adenosine triphosphate (ATP), and inositol 1,4,5-trisphosphate (IP3), among others. Therefore, they play a significant role in regulating cell homeostasis, proliferation, and differentiation. Alterations in Cx distribution, degradation, and post-translational modifications have been correlated with cancers, as well as cardiovascular and neurological diseases. Depending on the isoform, Cx have been shown either to promote or suppress the development of atherosclerosis, a progressive inflammatory disease affecting large and medium-sized arteries. Cx might contribute to the progression of the disease by enhancing endothelial dysfunction, monocyte recruitment, vascular smooth muscle cell (VSMC) activation, or by inhibiting VSMC autophagy. Inhibition or modulation of the expression of specific isoforms could suppress atherosclerotic plaque formation and diminish pro-inflammatory conditions. A better understanding of the complexity of atherosclerosis pathophysiology linked with Cx could result in developing novel therapeutic strategies. This review aims to present the role of Cx in the pathogenesis of atherosclerosis and discusses whether they can become novel therapeutic targets.
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Zhou M, Zheng M, Zhou X, Tian S, Yang X, Ning Y, Li Y, Zhang S. The roles of connexins and gap junctions in the progression of cancer. Cell Commun Signal 2023; 21:8. [PMID: 36639804 PMCID: PMC9837928 DOI: 10.1186/s12964-022-01009-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/03/2022] [Indexed: 01/15/2023] Open
Abstract
Gap junctions (GJs), which are composed of connexins (Cxs), provide channels for direct information exchange between cells. Cx expression has a strong spatial specificity; however, its influence on cell behavior and information exchange between cells cannot be ignored. A variety of factors in organisms can modulate Cxs and subsequently trigger a series of responses that have important effects on cellular behavior. The expression and function of Cxs and the number and function of GJs are in dynamic change. Cxs have been characterized as tumor suppressors in the past, but recent studies have highlighted the critical roles of Cxs and GJs in cancer pathogenesis. The complex mechanism underlying Cx and GJ involvement in cancer development is a major obstacle to the evolution of therapy targeting Cxs. In this paper, we review the post-translational modifications of Cxs, the interactions of Cxs with several chaperone proteins, and the effects of Cxs and GJs on cancer. Video Abstract.
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Affiliation(s)
- Mingming Zhou
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Minying Zheng
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
| | - Xinyue Zhou
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Shifeng Tian
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Xiaohui Yang
- grid.216938.70000 0000 9878 7032Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yidi Ning
- grid.216938.70000 0000 9878 7032Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yuwei Li
- grid.417031.00000 0004 1799 2675Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin, 300121 People’s Republic of China
| | - Shiwu Zhang
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
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Jiménez-Dinamarca I, Reyes-Lizana R, Lemunao-Inostroza Y, Cárdenas K, Castro-Lazo R, Peña F, Lucero CM, Prieto-Villalobos J, Retamal MA, Orellana JA, Stehberg J. GABAergic Regulation of Astroglial Gliotransmission through Cx43 Hemichannels. Int J Mol Sci 2022; 23:13625. [PMID: 36362410 PMCID: PMC9656947 DOI: 10.3390/ijms232113625] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/30/2022] [Accepted: 10/09/2022] [Indexed: 02/12/2024] Open
Abstract
Gamma-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. It is produced by interneurons and recycled by astrocytes. In neurons, GABA activates the influx of Cl- via the GABAA receptor or efflux or K+ via the GABAB receptor, inducing hyperpolarization and synaptic inhibition. In astrocytes, the activation of both GABAA and GABAB receptors induces an increase in intracellular Ca2+ and the release of glutamate and ATP. Connexin 43 (Cx43) hemichannels are among the main Ca2+-dependent cellular mechanisms for the astroglial release of glutamate and ATP. However, no study has evaluated the effect of GABA on astroglial Cx43 hemichannel activity and Cx43 hemichannel-mediated gliotransmission. Here we assessed the effects of GABA on Cx43 hemichannel activity in DI NCT1 rat astrocytes and hippocampal brain slices. We found that GABA induces a Ca2+-dependent increase in Cx43 hemichannel activity in astrocytes mediated by the GABAA receptor, as it was blunted by the GABAA receptor antagonist bicuculline but unaffected by GABAB receptor antagonist CGP55845. Moreover, GABA induced the Cx43 hemichannel-dependent release of glutamate and ATP, which was also prevented by bicuculline, but unaffected by CGP. Gliotransmission in response to GABA was also unaffected by pannexin 1 channel blockade. These results are discussed in terms of the possible role of astroglial Cx43 hemichannel-mediated glutamate and ATP release in regulating the excitatory/inhibitory balance in the brain and their possible contribution to psychiatric disorders.
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Affiliation(s)
- Ivanka Jiménez-Dinamarca
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Rachel Reyes-Lizana
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Yordan Lemunao-Inostroza
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Kevin Cárdenas
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Raimundo Castro-Lazo
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Francisca Peña
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Universidad del Desarrollo–Clínica Alemana, Santiago 7780272, Chile
| | - Claudia M. Lucero
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Mauricio Antonio Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Universidad del Desarrollo–Clínica Alemana, Santiago 7780272, Chile
| | - Juan Andrés Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
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10
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Quan M, Lv H, Liu Z, Li K, Zhang C, Shi L, Yang X, Lei P, Zhu Y, Ai D. MST1 Suppresses Disturbed Flow Induced Atherosclerosis. Circ Res 2022; 131:748-764. [PMID: 36164986 DOI: 10.1161/circresaha.122.321322] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Atherosclerosis occurs mainly at arterial branching points exposed to disturbed blood flow. How MST1 (mammalian sterile 20-like kinase 1), the primary kinase in the mechanosensitive Hippo pathway modulates disturbed flow induced endothelial cells (ECs) activation and atherosclerosis remains unclear. METHODS To assess the role of MST1 in vivo, mice with EC-specific Mst1 deficiency on ApoE-/- background (Mst1iECKOApoE-/-) were used in an atherosclerosis model generated by carotid artery ligation. Mass spectrometry, immunoprecipitation, proximity ligation assay, and dye uptake assay were used to identify the functional substrate of MST1. Human umbilical vein endothelial cells and human aortic endothelial cells were subjected to oscillatory shear stress that mimic disturbed flow in experiments conducted in vitro. RESULTS We found that the phosphorylation of endothelial MST1 was significantly inhibited in oscillatory shear stress-exposed regions of human and mouse arteries and ECs. Ectopic lenti-mediated overexpression of wild-type MST1, but not a kinase-deficient mutant of MST1, reversed disturbed flow-caused EC activation and atherosclerosis in EC-specific Mst1 deficiency on ApoE-/- background (Mst1iECKOApoE-/-). Inhibition of MST1 by oscillatory shear stress led to reduced phosphorylation of Cx43 (connexin 43) at Ser255, the Cx43 hemichannel open, EC activation, and atherosclerosis, which were blocked by TAT-GAP19, a Cx43 hemichannel inhibitory peptide. Mass spectrometry studies identified that Filamin B fueled the translocation of Cx43 to lipid rafts for further hemichannel open. Finally, lenti-mediated overexpression of the Cx43S255 mutant into glutamate to mimic phosphorylation blunted disturbed flow-induced EC activation, thereby inhibiting the atherogenesis in both ApoE-/- and Mst1 iECKOApoE-/- mice. CONCLUSIONS Our study reveals that inhibition of the MST1-Cx43 axis is an essential driver of oscillatory shear stress-induced endothelial dysfunction and atherosclerosis, which provides a new therapeutic target for the treatment of atherosclerosis.
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Affiliation(s)
- Meixi Quan
- Tianjin Institute of Cardiology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Second Hospital of Tianjin Medical University (M.Q., H.L., D.A.), Tianjin Medical University, China.,Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Huizhen Lv
- Tianjin Institute of Cardiology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Second Hospital of Tianjin Medical University (M.Q., H.L., D.A.), Tianjin Medical University, China.,Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Zening Liu
- Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Kan Li
- Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Chenghu Zhang
- Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Lei Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences (L.S.), Tianjin Medical University, China
| | - XinYu Yang
- Department of Neurosurgery (X.Y.), Tianjin Medical University General Hospital, China
| | - Ping Lei
- Department of Geriatrics (P.L.), Tianjin Medical University General Hospital, China
| | - Yi Zhu
- Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
| | - Ding Ai
- Tianjin Institute of Cardiology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Second Hospital of Tianjin Medical University (M.Q., H.L., D.A.), Tianjin Medical University, China.,Department of Physiology and Pathophysiology (M.Q., H.L., Z.L., K.L., C.Z., Y.Z., D.A.), Tianjin Medical University, China
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11
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Zlomuzica A, Plank L, Dere E. A new path to mental disorders: Through gap junction channels and hemichannels. Neurosci Biobehav Rev 2022; 142:104877. [PMID: 36116574 DOI: 10.1016/j.neubiorev.2022.104877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/20/2022] [Accepted: 09/13/2022] [Indexed: 11/18/2022]
Abstract
Behavioral disturbances related to emotional regulation, reward processing, cognition, sleep-wake regulation and activity/movement represent core symptoms of most common mental disorders. Increasing empirical and theoretical evidence suggests that normal functioning of these behavioral domains relies on fine graded coordination of neural and glial networks which are maintained and modulated by intercellular gap junction channels and unapposed pannexin or connexin hemichannels. Dysfunctions in these networks might contribute to the development and maintenance of psychopathological and neurobiological features associated with mental disorders. Here we review and discuss the evidence indicating a prominent role of gap junction channel and hemichannel dysfunction in core symptoms of mental disorders. We further discuss how the increasing knowledge on intercellular gap junction channels and unapposed pannexin or connexin hemichannels in the brain might lead to deeper mechanistic insight in common mental disorders and to the development of novel treatment approaches. We further attempt to exemplify what type of future research on this topic could be integrated into multidimensional approaches to understand and cure mental disorders.
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Affiliation(s)
- Armin Zlomuzica
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany.
| | - Laurin Plank
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany
| | - Ekrem Dere
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany; Sorbonne Université. Institut de Biologie Paris-Seine, (IBPS), Département UMR 8256: Adaptation Biologique et Vieillissement, UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Bâtiment B, 9 quai Saint Bernard, F-75005 Paris, France.
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12
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McDouall A, Zhou KQ, Bennet L, Green CR, Gunn AJ, Davidson JO. Connexins, Pannexins and Gap Junctions in Perinatal Brain Injury. Biomedicines 2022; 10:1445. [PMID: 35740466 PMCID: PMC9220888 DOI: 10.3390/biomedicines10061445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/15/2022] [Accepted: 06/15/2022] [Indexed: 11/18/2022] Open
Abstract
Perinatal brain injury secondary to hypoxia-ischemia and/or infection/inflammation remains a major cause of disability. Therapeutic hypothermia significantly improves outcomes, but in randomized controlled trials nearly half of infants still died or survived with disability, showing that additional interventions are needed. There is growing evidence that brain injury spreads over time from injured to previously uninjured regions of the brain. At least in part, this spread is related to opening of connexin hemichannels and pannexin channels, both of which are large conductance membrane channels found in many brain cells. Opening of these membrane channels releases adenosine triphosphate (ATP), and other neuroactive molecules, into the extracellular space. ATP has an important role in normal signaling, but pathologically can trigger the assembly of the multi-protein inflammasome complex. The inflammasome complex promotes activation of inflammatory caspases, and release of inflammatory cytokines. Overall, the connexin hemichannel appears to play a primary role in propagation of injury and chronic disease, and connexin hemichannel blockade has been shown to be neuroprotective in multiple animal models. Thus, there is potential for some blockers of connexin or pannexin channels to be developed into targeted interventions that could be used in conjunction with or separate to therapeutic hypothermia.
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Affiliation(s)
- Alice McDouall
- U1 Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand; (A.M.); (K.Q.Z.); (L.B.); (A.J.G.)
| | - Kelly Q. Zhou
- U1 Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand; (A.M.); (K.Q.Z.); (L.B.); (A.J.G.)
| | - Laura Bennet
- U1 Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand; (A.M.); (K.Q.Z.); (L.B.); (A.J.G.)
| | - Colin R. Green
- Department of Ophthalmology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand;
| | - Alistair J. Gunn
- U1 Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand; (A.M.); (K.Q.Z.); (L.B.); (A.J.G.)
| | - Joanne O. Davidson
- U1 Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1023, New Zealand; (A.M.); (K.Q.Z.); (L.B.); (A.J.G.)
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13
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Retamal MA, Altenberg GA. Role and Posttranslational Regulation of Cx46 Hemichannels and Gap Junction Channels in the Eye Lens. Front Physiol 2022; 13:864948. [PMID: 35431975 PMCID: PMC9006113 DOI: 10.3389/fphys.2022.864948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/14/2022] [Indexed: 12/31/2022] Open
Abstract
Connexins are a family of proteins that can form two distinct types of channels: hemichannels and gap junction channels. Hemichannels are composed of six connexin subunits and when open allow for exchanges between the cytoplasm and the extracellular milieu. Gap junction channels are formed by head-to-head docking of two hemichannels in series, each one from one of two adjacent cells. These channels allow for exchanges between the cytoplasms of contacting cells. The lens is a transparent structure located in the eye that focuses light on the retina. The transparency of the lens depends on its lack of blood irrigation and the absence of organelles in its cells. To survive such complex metabolic scenario, lens cells express Cx43, Cx46 and Cx50, three connexins isoforms that form hemichannels and gap junction channels that allow for metabolic cooperation between lens cells. This review focuses on the roles of Cx46 hemichannels and gap junction channels in the lens under physiological conditions and in the formation of cataracts, with emphasis on the modulation by posttranslational modifications.
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Affiliation(s)
- Mauricio A. Retamal
- Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Clínica Alemana Facultad de Medicina, Santiago, Chile
- Universidad del Desarrollo, Programa de Comunicación Celular en Cáncer, Clínica Alemana Facultad de Medicina, Santiago, Chile
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- *Correspondence: Mauricio A. Retamal, ; Guillermo A. Altenberg,
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, United States
- *Correspondence: Mauricio A. Retamal, ; Guillermo A. Altenberg,
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14
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Peng B, Xu C, Wang S, Zhang Y, Li W. The Role of Connexin Hemichannels in Inflammatory Diseases. BIOLOGY 2022; 11:biology11020237. [PMID: 35205103 PMCID: PMC8869213 DOI: 10.3390/biology11020237] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/04/2023]
Abstract
The connexin protein family consists of approximately 20 members, and is well recognized as the structural unit of the gap junction channels that perforate the plasma membranes of coupled cells and, thereby, mediate intercellular communication. Gap junctions are assembled by two preexisting hemichannels on the membranes of apposing cells. Non-junctional connexin hemichannels (CxHC) provide a conduit between the cell interior and the extracellular milieu, and are believed to be in a protectively closed state under physiological conditions. The development and characterization of the peptide mimetics of the amino acid sequences of connexins have resulted in the development of a panel of blockers with a higher selectivity for CxHC, which have become important tools for defining the role of CxHC in various biological processes. It is increasingly clear that CxHC can be induced to open by pathogen-associated molecular patterns. The opening of CxHC facilitates the release of damage-associated molecular patterns, a class of endogenous molecules that are critical for the pathogenesis of inflammatory diseases. The blockade of CxHC leads to attenuated inflammation, reduced tissue injury and improved organ function in human and animal models of about thirty inflammatory diseases and disorders. These findings demonstrate that CxHC may contribute to the intensification of inflammation, and serve as a common target in the treatments of various inflammatory diseases. In this review, we provide an update on the progress in the understanding of CxHC, with a focus on the role of these channels in inflammatory diseases.
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Affiliation(s)
| | | | | | - Yijie Zhang
- Correspondence: (Y.Z.); (W.L.); Tel.: +86-13903782431 (Y.Z.); +86-17839250252 (W.L.)
| | - Wei Li
- Correspondence: (Y.Z.); (W.L.); Tel.: +86-13903782431 (Y.Z.); +86-17839250252 (W.L.)
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15
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Linsambarth S, Carvajal FJ, Moraga‐Amaro R, Mendez L, Tamburini G, Jimenez I, Verdugo DA, Gómez GI, Jury N, Martínez P, Zundert B, Varela‐Nallar L, Retamal MA, Martin C, Altenberg GA, Fiori MC, Cerpa W, Orellana JA, Stehberg J. Astroglial gliotransmitters released via Cx43 hemichannels regulate NMDAR‐dependent transmission and short‐term fear memory in the basolateral amygdala. FASEB J 2022; 36:e22134. [DOI: 10.1096/fj.202100798rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Sergio Linsambarth
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Francisco J. Carvajal
- Laboratorio de Función y Patología Neuronal Departamento de Biología Celular y Molecular Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Rodrigo Moraga‐Amaro
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Luis Mendez
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Giovanni Tamburini
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Ivanka Jimenez
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Daniel Antonio Verdugo
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Gonzalo I. Gómez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud Universidad Autónoma de Chile Santiago Chile
| | - Nur Jury
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Pablo Martínez
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Brigitte Zundert
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Lorena Varela‐Nallar
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa. Facultad de Medicina Clínica Alemana Universidad del Desarrollo Santiago Chile
| | - Claire Martin
- Unité de Biologie Fonctionnelle et Adaptative Centre National la Recherche Scientifique Unité Mixte de Recherche 8251 Université Paris Diderot, Sorbonne Paris Cité Paris France
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics Center for Membrane Protein Research Texas Tech University Health Sciences Center Lubbock Texas USA
| | - Mariana C. Fiori
- Department of Cell Physiology and Molecular Biophysics Center for Membrane Protein Research Texas Tech University Health Sciences Center Lubbock Texas USA
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal Departamento de Biología Celular y Molecular Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juan A. Orellana
- Departamento de Neurología Escuela de Medicina Pontificia Universidad Católica de Chile Santiago Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
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16
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King DR, Sedovy MW, Leng X, Xue J, Lamouille S, Koval M, Isakson BE, Johnstone SR. Mechanisms of Connexin Regulating Peptides. Int J Mol Sci 2021; 22:ijms221910186. [PMID: 34638526 PMCID: PMC8507914 DOI: 10.3390/ijms221910186] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/22/2022] Open
Abstract
Gap junctions (GJ) and connexins play integral roles in cellular physiology and have been found to be involved in multiple pathophysiological states from cancer to cardiovascular disease. Studies over the last 60 years have demonstrated the utility of altering GJ signaling pathways in experimental models, which has led to them being attractive targets for therapeutic intervention. A number of different mechanisms have been proposed to regulate GJ signaling, including channel blocking, enhancing channel open state, and disrupting protein-protein interactions. The primary mechanism for this has been through the design of numerous peptides as therapeutics, that are either currently in early development or are in various stages of clinical trials. Despite over 25 years of research into connexin targeting peptides, the overall mechanisms of action are still poorly understood. In this overview, we discuss published connexin targeting peptides, their reported mechanisms of action, and the potential for these molecules in the treatment of disease.
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Affiliation(s)
- D. Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
| | - Meghan W. Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, VA 24061, USA
| | - Xinyan Leng
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
| | - Jianxiang Xue
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (J.X.); (B.E.I.)
| | - Samy Lamouille
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Center for Vascular and Heart Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Michael Koval
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (J.X.); (B.E.I.)
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Scott R. Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Center for Vascular and Heart Research, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
- Correspondence:
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17
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Coutinho FP, Green CR, Acosta ML, Rupenthal ID. Xentry-Gap19 inhibits Connexin43 hemichannel opening especially during hypoxic injury. Drug Deliv Transl Res 2021; 10:751-765. [PMID: 32318976 PMCID: PMC7223318 DOI: 10.1007/s13346-020-00763-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hypoxic injury results in cell death, tissue damage and activation of inflammatory pathways. This is mediated by pathological Connexin43 (Cx43) hemichannel (HC) opening resulting in osmotic and ionic imbalances as well as cytokine production perpetuating the inflammatory environment. Gap19 is an intracellularly acting Cx43 mimetic peptide that blocks HC opening and thus promotes cell survival. However, native Gap19, which must enter the cell in order to function, exhibits low cell permeability. In this study, Gap19 was conjugated to the cell-penetrating peptide, Xentry, to investigate if cellular uptake could be improved while maintaining peptide function. Cellular uptake of Xentry-Gap19 (XG19) was much greater than that of native Gap19 even under normal cell culture conditions. Peptide function was maintained post uptake as shown by reduced ethidium homodimer influx and ATP release due to Cx43 HC block. While XG19 blocked pathologic HC opening though, normal gap junction communication required for cell repair and survival mechanisms was not affected as shown in a dye scrape-load assay. Under hypoxic conditions, increased expression of Syndecan-4, a plasma membrane proteoglycan targeted by Xentry, enabled even greater XG19 uptake leading to higher inhibition of ATP release and greater cell survival. This suggests that XG19, which is targeted specifically to hypoxic cells, can efficiently and safely block Cx43 HC and could therefore be a novel treatment for hypoxic and inflammatory diseases. Graphical abstract ![]()
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Affiliation(s)
- Frazer P Coutinho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Monica L Acosta
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
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18
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Marsh SR, Williams ZJ, Pridham KJ, Gourdie RG. Peptidic Connexin43 Therapeutics in Cardiac Reparative Medicine. J Cardiovasc Dev Dis 2021; 8:52. [PMID: 34063001 PMCID: PMC8147937 DOI: 10.3390/jcdd8050052] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/19/2021] [Accepted: 05/01/2021] [Indexed: 12/12/2022] Open
Abstract
Connexin (Cx43)-formed channels have been linked to cardiac arrhythmias and diseases of the heart associated with myocardial tissue loss and fibrosis. These pathologies include ischemic heart disease, ischemia-reperfusion injury, heart failure, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and Duchenne muscular dystrophy. A number of Cx43 mimetic peptides have been reported as therapeutic candidates for targeting disease processes linked to Cx43, including some that have advanced to clinical testing in humans. These peptides include Cx43 sequences based on the extracellular loop domains (e.g., Gap26, Gap 27, and Peptide5), cytoplasmic-loop domain (Gap19 and L2), and cytoplasmic carboxyl-terminal domain (e.g., JM2, Cx43tat, CycliCX, and the alphaCT family of peptides) of this transmembrane protein. Additionally, RYYN peptides binding to the Cx43 carboxyl-terminus have been described. In this review, we survey preclinical and clinical data available on short mimetic peptides based on, or directly targeting, Cx43, with focus on their potential for treating heart disease. We also discuss problems that have caused reluctance within the pharmaceutical industry to translate peptidic therapeutics to the clinic, even when supporting preclinical data is strong. These issues include those associated with the administration, stability in vivo, and tissue penetration of peptide-based therapeutics. Finally, we discuss novel drug delivery technologies including nanoparticles, exosomes, and other nanovesicular carriers that could transform the clinical and commercial viability of Cx43-targeting peptides in treatment of heart disease, stroke, cancer, and other indications requiring oral or parenteral administration. Some of these newly emerging approaches to drug delivery may provide a path to overcoming pitfalls associated with the drugging of peptide therapeutics.
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Affiliation(s)
- Spencer R. Marsh
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Zachary J. Williams
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA 24016, USA
| | - Kevin J. Pridham
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute at VTC, Virginia Tech, Roanoke, VA 24016, USA; (S.R.M.); (Z.J.W.); (K.J.P.)
- Center for Heart and Reparative Medicine Research, Virginia Tech, Roanoke, VA 24016, USA
- Translational Biology Medicine and Health Graduate Program, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA
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19
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Hirschhäuser C, Lissoni A, Görge PM, Lampe PD, Heger J, Schlüter KD, Leybaert L, Schulz R, Boengler K. Connexin 43 phosphorylation by casein kinase 1 is essential for the cardioprotection by ischemic preconditioning. Basic Res Cardiol 2021; 116:21. [PMID: 33751227 PMCID: PMC7985055 DOI: 10.1007/s00395-021-00861-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/10/2021] [Indexed: 02/07/2023]
Abstract
Myocardial connexin 43 (Cx43) forms gap junctions and hemichannels, and is also present within subsarcolemmal mitochondria. The protein is phosphorylated by several kinases including mitogen-activated protein kinase (MAPK), protein kinase C (PKC), and casein kinase 1 (CK1). A reduction in Cx43 content abrogates myocardial infarct size reduction by ischemic preconditioning (IPC). The present study characterizes the contribution of Cx43 phosphorylation towards mitochondrial function, hemichannel activity, and the cardioprotection by IPC in wild-type (WT) mice and in mice in which Cx43-phosphorylation sites targeted by above kinases are mutated to non-phosphorylatable residues (Cx43MAPKmut, Cx43PKCmut, and Cx43CK1mut mice). The amount of Cx43 in the left ventricle and in mitochondria was reduced in all mutant strains compared to WT mice and Cx43 phosphorylation was altered at residues not directly targeted by the mutations. Whereas complex 1 respiration was reduced in all strains, complex 2 respiration was decreased in Cx43CK1mut mice only. In Cx43 epitope-mutated mice, formation of reactive oxygen species and opening of the mitochondrial permeability transition pore were not affected. The hemichannel open probability was reduced in Cx43PKCmut and Cx43CK1mut but not in Cx43MAPKmut cardiomyocytes. Infarct size in isolated saline-perfused hearts after ischemia/reperfusion (45 min/120 min) was comparable between genotypes and was significantly reduced by IPC (3 × 3 min ischemia/5 min reperfusion) in WT, Cx43MAPKmut, and Cx43PKCmut, but not in Cx43CK1mut mice, an effect independent from the amount of Cx43 and the probability of hemichannel opening. Taken together, our study shows that alterations of Cx43 phosphorylation affect specific cellular functions and highlights the importance of Cx43 phosphorylation by CK1 for IPC's cardioprotection.
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Affiliation(s)
- Christine Hirschhäuser
- Institut für Physiologie, Justus-Liebig Universität Gießen, Aulweg 129, 35392, Giessen, Germany
| | - Alessio Lissoni
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | | | - Paul D Lampe
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jacqueline Heger
- Institut für Physiologie, Justus-Liebig Universität Gießen, Aulweg 129, 35392, Giessen, Germany
| | - Klaus-Dieter Schlüter
- Institut für Physiologie, Justus-Liebig Universität Gießen, Aulweg 129, 35392, Giessen, Germany
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Rainer Schulz
- Institut für Physiologie, Justus-Liebig Universität Gießen, Aulweg 129, 35392, Giessen, Germany
| | - Kerstin Boengler
- Institut für Physiologie, Justus-Liebig Universität Gießen, Aulweg 129, 35392, Giessen, Germany.
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20
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Natha CM, Vemulapalli V, Fiori MC, Chang CWT, Altenberg GA. Connexin hemichannel inhibitors with a focus on aminoglycosides. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166115. [PMID: 33711451 DOI: 10.1016/j.bbadis.2021.166115] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/06/2021] [Accepted: 02/22/2021] [Indexed: 12/31/2022]
Abstract
Connexins are membrane proteins involved directly in cell-to-cell communication through the formation of gap-junctional channels. These channels result from the head-to-head docking of two hemichannels, one from each of two adjacent cells. Undocked hemichannels are also present at the plasma membrane where they mediate the efflux of molecules that participate in autocrine and paracrine signaling, but abnormal increase in hemichannel activity can lead to cell damage in disorders such as cardiac infarct, stroke, deafness, cataracts, and skin diseases. For this reason, connexin hemichannels have emerged as a valid therapeutic target. Know small molecule hemichannel inhibitors are not ideal leads for the development of better drugs for clinical use because they are not specific and/or have toxic effects. Newer inhibitors are more selective and include connexin mimetic peptides, anti-connexin antibodies and drugs that reduce connexin expression such as antisense oligonucleotides. Re-purposed drugs and their derivatives are also promising because of the significant experience with their clinical use. Among these, aminoglycoside antibiotics have been identified as inhibitors of connexin hemichannels that do not inhibit gap-junctional channels. In this review, we discuss connexin hemichannels and their inhibitors, with a focus on aminoglycoside antibiotics and derivatives of kanamycin A that inhibit connexin hemichannels, but do not have antibiotic effect.
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Affiliation(s)
- Cristina M Natha
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Varun Vemulapalli
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Mariana C Fiori
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Cheng-Wei T Chang
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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21
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Martins-Marques T, Hausenloy DJ, Sluijter JPG, Leybaert L, Girao H. Intercellular Communication in the Heart: Therapeutic Opportunities for Cardiac Ischemia. Trends Mol Med 2021; 27:248-262. [PMID: 33139169 DOI: 10.1016/j.molmed.2020.10.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/04/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022]
Abstract
The maintenance of tissue, organ, and organism homeostasis relies on an intricate network of players and mechanisms that assist in the different forms of cell-cell communication. Myocardial infarction, following heart ischemia and reperfusion, is associated with profound changes in key processes of intercellular communication, involving gap junctions, extracellular vesicles, and tunneling nanotubes, some of which have been implicated in communication defects associated with cardiac injury, namely arrhythmogenesis and progression into heart failure. Therefore, intercellular communication players have emerged as attractive powerful therapeutic targets aimed at preserving a fine-tuned crosstalk between the different cardiac cells in order to prevent or repair some of harmful consequences of heart ischemia and reperfusion, re-establishing myocardial function.
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Affiliation(s)
- Tania Martins-Marques
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal; Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal; Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Derek J Hausenloy
- Cardiovascular & Metabolic Disorders Program, Duke-National University of Singapore Medical School, Singapore; National Heart Research Institute Singapore, National Heart Centre, Singapore; Yong Loo Lin School of Medicine, National University Singapore, Singapore; The Hatter Cardiovascular Institute, University College London, London, UK; Cardiovascular Research Center, College of Medical and Health Sciences, Asia University, Taiwan
| | - Joost P G Sluijter
- Laboratory of Experimental Cardiology, UMC Utrecht Regenerative Medicine Center, Circulatory Health Laboratory, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Henrique Girao
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal; Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal; Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal.
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22
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Andelova K, Egan Benova T, Szeiffova Bacova B, Sykora M, Prado NJ, Diez ER, Hlivak P, Tribulova N. Cardiac Connexin-43 Hemichannels and Pannexin1 Channels: Provocative Antiarrhythmic Targets. Int J Mol Sci 2020; 22:ijms22010260. [PMID: 33383853 PMCID: PMC7795512 DOI: 10.3390/ijms22010260] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac connexin-43 (Cx43) creates gap junction channels (GJCs) at intercellular contacts and hemi-channels (HCs) at the peri-junctional plasma membrane and sarcolemmal caveolae/rafts compartments. GJCs are fundamental for the direct cardiac cell-to-cell transmission of electrical and molecular signals which ensures synchronous myocardial contraction. The HCs and structurally similar pannexin1 (Panx1) channels are active in stressful conditions. These channels are essential for paracrine and autocrine communication through the release of ions and signaling molecules to the extracellular environment, or for uptake from it. The HCs and Panx1 channel-opening profoundly affects intracellular ionic homeostasis and redox status and facilitates via purinergic signaling pro-inflammatory and pro-fibrotic processes. These conditions promote cardiac arrhythmogenesis due to the impairment of the GJCs and selective ion channel function. Crosstalk between GJCs and HCs/Panx1 channels could be crucial in the development of arrhythmogenic substrates, including fibrosis. Despite the knowledge gap in the regulation of these channels, current evidence indicates that HCs and Panx1 channel activation can enhance the risk of cardiac arrhythmias. It is extremely challenging to target HCs and Panx1 channels by inhibitory agents to hamper development of cardiac rhythm disorders. Progress in this field may contribute to novel therapeutic approaches for patients prone to develop atrial or ventricular fibrillation.
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Affiliation(s)
- Katarina Andelova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Tamara Egan Benova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Barbara Szeiffova Bacova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Matus Sykora
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
| | - Natalia Jorgelina Prado
- Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, M5500 Mendoza, Argentina; (N.J.P.); (E.R.D.)
| | - Emiliano Raul Diez
- Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas, M5500 Mendoza, Argentina; (N.J.P.); (E.R.D.)
| | - Peter Hlivak
- Department of Arrhythmias and Pacing, National Institute of Cardiovascular Diseases, Pod Krásnou Hôrkou 1, 83348 Bratislava, Slovakia;
| | - Narcis Tribulova
- Centre of Experimental Medicine, Slovak Academy of Sciences, Institute for Heart Research, 84104 Bratislava, Slovakia; (K.A.); (T.E.B.); (B.S.B.); (M.S.)
- Correspondence: ; Tel.: +421-2-32295-423
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23
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Mulkearns-Hubert EE, Reizes O, Lathia JD. Connexins in Cancer: Jekyll or Hyde? Biomolecules 2020; 10:E1654. [PMID: 33321749 PMCID: PMC7764653 DOI: 10.3390/biom10121654] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 12/16/2022] Open
Abstract
The expression, localization, and function of connexins, the protein subunits that comprise gap junctions, are often altered in cancer. In addition to cell-cell coupling through gap junction channels, connexins also form hemichannels that allow communication between the cell and the extracellular space and perform non-junctional intracellular activities. Historically, connexins have been considered tumor suppressors; however, they can also serve tumor-promoting functions in some contexts. Here, we review the literature surrounding connexins in cancer cells in terms of specific connexin functions and propose that connexins function upstream of most, if not all, of the hallmarks of cancer. The development of advanced connexin targeting approaches remains an opportunity for the field to further interrogate the role of connexins in cancer phenotypes, particularly through the use of in vivo models. More specific modulators of connexin function will both help elucidate the functions of connexins in cancer and advance connexin-specific therapies in the clinic.
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Affiliation(s)
- Erin E. Mulkearns-Hubert
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (O.R.); (J.D.L.)
| | - Ofer Reizes
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (O.R.); (J.D.L.)
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College, Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Justin D. Lathia
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (O.R.); (J.D.L.)
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College, Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
- Rose Ella Burkhardt Brain Tumor and Neuro-Oncology Center, Cleveland Clinic, Cleveland, OH, 44195, USA
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24
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Strauss RE, Gourdie RG. Cx43 and the Actin Cytoskeleton: Novel Roles and Implications for Cell-Cell Junction-Based Barrier Function Regulation. Biomolecules 2020; 10:E1656. [PMID: 33321985 PMCID: PMC7764618 DOI: 10.3390/biom10121656] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
Barrier function is a vital homeostatic mechanism employed by epithelial and endothelial tissue. Diseases across a wide range of tissue types involve dynamic changes in transcellular junctional complexes and the actin cytoskeleton in the regulation of substance exchange across tissue compartments. In this review, we focus on the contribution of the gap junction protein, Cx43, to the biophysical and biochemical regulation of barrier function. First, we introduce the structure and canonical channel-dependent functions of Cx43. Second, we define barrier function and examine the key molecular structures fundamental to its regulation. Third, we survey the literature on the channel-dependent roles of connexins in barrier function, with an emphasis on the role of Cx43 and the actin cytoskeleton. Lastly, we discuss findings on the channel-independent roles of Cx43 in its associations with the actin cytoskeleton and focal adhesion structures highlighted by PI3K signaling, in the potential modulation of cellular barriers. Mounting evidence of crosstalk between connexins, the cytoskeleton, focal adhesion complexes, and junctional structures has led to a growing appreciation of how barrier-modulating mechanisms may work together to effect solute and cellular flux across tissue boundaries. This new understanding could translate into improved therapeutic outcomes in the treatment of barrier-associated diseases.
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Affiliation(s)
- Randy E. Strauss
- Virginia Tech, Translational Biology Medicine and Health (TBMH) Program, Roanoke, VA 24016, USA
| | - Robert G. Gourdie
- Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
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25
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Astrocytic Connexin43 Channels as Candidate Targets in Epilepsy Treatment. Biomolecules 2020; 10:biom10111578. [PMID: 33233647 PMCID: PMC7699773 DOI: 10.3390/biom10111578] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
In epilepsy research, emphasis is put on exploring non-neuronal targets such as astrocytic proteins, since many patients remain pharmacoresistant to current treatments, which almost all target neuronal mechanisms. This paper reviews available data on astrocytic connexin43 (Cx43) signaling in seizures and epilepsy. Cx43 is a widely expressed transmembrane protein and the constituent of gap junctions (GJs) and hemichannels (HCs), allowing intercellular and extracellular communication, respectively. A plethora of research papers show altered Cx43 mRNA levels, protein expression, phosphorylation state, distribution and/or functional coupling in human epileptic tissue and experimental models. Human Cx43 mutations are linked to seizures as well, as 30% of patients with oculodentodigital dysplasia (ODDD), a rare genetic condition caused by mutations in the GJA1 gene coding for Cx43 protein, exhibit neurological symptoms including seizures. Cx30/Cx43 double knock-out mice show increased susceptibility to evoked epileptiform events in brain slices due to impaired GJ-mediated redistribution of K+ and glutamate and display a higher frequency of spontaneous generalized chronic seizures in an epilepsy model. Contradictory, Cx30/Cx43 GJs can traffic nutrients to high-energy demanding neurons and initiate astrocytic Ca2+ waves and hyper synchronization, thereby supporting proconvulsant effects. The general connexin channel blocker carbenoxolone and blockers from the fenamate family diminish epileptiform activity in vitro and improve seizure outcome in vivo. In addition, interventions with more selective peptide inhibitors of HCs display anticonvulsant actions. To conclude, further studies aiming to disentangle distinct roles of HCs and GJs are necessary and tools specifically targeting Cx43 HCs may facilitate the search for novel epilepsy treatments.
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26
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Lissoni A, Wang N, Nezlobinskii T, De Smet M, Panfilov AV, Vandersickel N, Leybaert L, Witschas K. Gap19, a Cx43 Hemichannel Inhibitor, Acts as a Gating Modifier That Decreases Main State Opening While Increasing Substate Gating. Int J Mol Sci 2020; 21:ijms21197340. [PMID: 33027889 PMCID: PMC7583728 DOI: 10.3390/ijms21197340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/12/2020] [Accepted: 09/25/2020] [Indexed: 02/05/2023] Open
Abstract
Cx43 hemichannels (HCs) are electrically and chemically gated transmembrane pores with low open probability and multiple conductance states, which makes kinetic studies of channel gating in large datasets challenging. Here, we developed open access software, named HemiGUI, to analyze HC gating transitions and investigated voltage-induced HC opening based on up to ≈4000 events recorded in HeLa-Cx43-overexpressing cells. We performed a detailed characterization of Cx43 HC gating profiles and specifically focused on the role of the C-terminal tail (CT) domain by recording the impact of adding an EGFP tag to the Cx43 CT end (Cx43-EGFP) or by supplying the Cx43 HC-inhibiting peptide Gap19 that interferes with CT interaction with the cytoplasmic loop (CL). We found that Gap19 not only decreased HC opening activity to the open state (≈217 pS) but also increased the propensity of subconductance (≈80 pS) transitions that additionally became slower as compared to the control. The work demonstrates that large sample transition analysis allows detailed investigations on Cx43 HC gating and shows that Gap19 acts as a HC gating modifier by interacting with the CT that forms a crucial gating element.
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Affiliation(s)
- Alessio Lissoni
- Department of Basic and Applied Medical Sciences—Physiology Group, Ghent University, 9000 Ghent, Belgium; (A.L.); (N.W.); (M.D.S.)
| | - Nan Wang
- Department of Basic and Applied Medical Sciences—Physiology Group, Ghent University, 9000 Ghent, Belgium; (A.L.); (N.W.); (M.D.S.)
| | - Timur Nezlobinskii
- Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium; (T.N.); (A.V.P.); (N.V.)
| | - Maarten De Smet
- Department of Basic and Applied Medical Sciences—Physiology Group, Ghent University, 9000 Ghent, Belgium; (A.L.); (N.W.); (M.D.S.)
| | - Alexander V. Panfilov
- Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium; (T.N.); (A.V.P.); (N.V.)
- Laboratory of Computational Biology and Medicine, Ural Federal University, 620075 Ekaterinburg, Russia
| | - Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium; (T.N.); (A.V.P.); (N.V.)
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences—Physiology Group, Ghent University, 9000 Ghent, Belgium; (A.L.); (N.W.); (M.D.S.)
- Correspondence: (L.L.); (K.W.); Tel.: +32-9-332-3366 (L.L.); +32-9-332-6944 (K.W.)
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences—Physiology Group, Ghent University, 9000 Ghent, Belgium; (A.L.); (N.W.); (M.D.S.)
- Correspondence: (L.L.); (K.W.); Tel.: +32-9-332-3366 (L.L.); +32-9-332-6944 (K.W.)
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27
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Caufriez A, Böck D, Martin C, Ballet S, Vinken M. Peptide-based targeting of connexins and pannexins for therapeutic purposes. Expert Opin Drug Discov 2020; 15:1213-1222. [PMID: 32539572 DOI: 10.1080/17460441.2020.1773787] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Connexin and pannexin (hemi)channels play an important role in paracrine and autocrine signaling pathways. The opening of these cellular pores is linked to a wide range of diseases. Therefore, pharmacological closing of connexin and pannexin (hemi)channels seems a promising therapeutic strategy. However, the currently available inhibitors cope with recurring problems concerning selectivity, specificity, stability and/or solubility. AREAS COVERED A number of peptides that mimic specific regions in the native sequence of connexins and pannexins have the potential to overcome some of these hurdles. In this paper, an overview is provided on these peptide-based inhibitors of connexin and pannexin (hemi)channels for therapeutic purposes. The authors also provide the reader with their expert perspectives on the future of these peptide-based inhibitors. EXPERT OPINION Peptide mimetics can become valuable tools in the treatment of connexin-related and pannexin-related diseases. This can be made possible provided that available peptides are optimized, and new peptide mimetics are designed based on knowledge of the mechanisms underlying the gating control of connexin and pannexin (hemi)channels.
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Affiliation(s)
- Anne Caufriez
- Department of in Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , 1090, Brussels, Belgium
| | - Denise Böck
- Department of in Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , 1090, Brussels, Belgium
| | - Charlotte Martin
- Department of Organic Chemistry, Vrije Universiteit Brussel , 1050, Brussels, Belgium
| | - Steven Ballet
- Department of Organic Chemistry, Vrije Universiteit Brussel , 1050, Brussels, Belgium
| | - Mathieu Vinken
- Department of in Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel , 1090, Brussels, Belgium
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28
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Sáez JC, Vargas AA, Hernández DE, Ortiz FC, Giaume C, Orellana JA. Permeation of Molecules through Astroglial Connexin 43 Hemichannels Is Modulated by Cytokines with Parameters Depending on the Permeant Species. Int J Mol Sci 2020; 21:ijms21113970. [PMID: 32492823 PMCID: PMC7312936 DOI: 10.3390/ijms21113970] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
Recent studies indicate that connexin hemichannels do not act as freely permeable non-selective pores, but they select permeants in an isoform-specific manner with cooperative, competitive and saturable kinetics. The aim of this study was to investigate whether the treatment with a mixture of IL-1β plus TNF-α, a well-known pro-inflammatory condition that activates astroglial connexin 43 (Cx43) hemichannels, could alter their permeability to molecules. We found that IL-1β plus TNF-α left-shifted the dye uptake rate vs. dye concentration relationship for Etd and 2-NBDG, but the opposite took place for DAPI or YO-PRO-1, whereas no alterations were observed for Prd. The latter modifications were accompanied of changes in Kd (Etd, DAPI, YO-PRO-1 or 2-NBDG) and Hill coefficients (Etd and YO-PRO-1), but not in alterations of Vmax. We speculate that IL-1β plus TNF-α may distinctively affect the binding sites to permeants in astroglial Cx43 hemichannels rather than their number in the cell surface. Alternatively, IL-1β plus TNF-α could induce the production of endogenous permeants that may favor or compete for in the pore-lining residues of Cx43 hemichannels. Future studies shall elucidate whether the differential ionic/molecule permeation of Cx43 hemichannels in astrocytes could impact their communication with neurons in the normal and inflamed nervous system.
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Affiliation(s)
- Juan C. Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.C.S.); (D.E.H.)
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso 2381850, Chile
| | - Aníbal A. Vargas
- Instituto de Ciencias de la Salud, Universidad de O′Higgins, Rancagua 2820000, Chile;
| | - Diego E. Hernández
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.C.S.); (D.E.H.)
| | - Fernando C. Ortiz
- Mechanisms on Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago 8910060, Chile;
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL Research University, 75005 Paris, France;
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
- Correspondence: ; Tel.: +56-2-968399128
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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30
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Interferon-γ and high glucose-induced opening of Cx43 hemichannels causes endothelial cell dysfunction and damage. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 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] [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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31
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HIV gp120 Protein Increases the Function of Connexin 43 Hemichannels and Pannexin-1 Channels in Astrocytes: Repercussions on Astroglial Function. Int J Mol Sci 2020; 21:ijms21072503. [PMID: 32260308 PMCID: PMC7178136 DOI: 10.3390/ijms21072503] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 11/17/2022] Open
Abstract
At least half of human immunodeficiency virus (HIV)-infected individuals suffer from a wide range of cognitive, behavioral and motor deficits, collectively known as HIV-associated neurocognitive disorders (HAND). The molecular mechanisms that amplify damage within the brain of HIV-infected individuals are unknown. Recently, we described that HIV augments the opening of connexin-43 (Cx43) hemichannels in cultured human astrocytes, which result in the collapse of neuronal processes. Whether HIV soluble viral proteins such as gp120, can regulate hemichannel opening in astrocytes is still ignored. These channels communicate the cytosol with the extracellular space during pathological conditions. We found that gp120 enhances the function of both Cx43 hemichannels and pannexin-1 channels in mouse cortical astrocytes. These effects depended on the activation of IL-1β/TNF-α, p38 MAP kinase, iNOS, cytoplasmic Ca2+ and purinergic signaling. The gp120-induced channel opening resulted in alterations in Ca2+ dynamics, nitric oxide production and ATP release. Although the channel opening evoked by gp120 in astrocytes was reproduced in ex vivo brain preparations, these responses were heterogeneous depending on the CA1 region analyzed. We speculate that soluble gp120-induced activation of astroglial Cx43 hemichannels and pannexin-1 channels could be crucial for the pathogenesis of HAND.
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Ramadan R, Vromans E, Anang DC, Goetschalckx I, Hoorelbeke D, Decrock E, Baatout S, Leybaert L, Aerts A. Connexin43 Hemichannel Targeting With TAT-Gap19 Alleviates Radiation-Induced Endothelial Cell Damage. Front Pharmacol 2020; 11:212. [PMID: 32210810 PMCID: PMC7066501 DOI: 10.3389/fphar.2020.00212] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/14/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Emerging evidence indicates an excess risk of late occurring cardiovascular diseases, especially atherosclerosis, after thoracic cancer radiotherapy. Ionizing radiation (IR) induces cellular effects which may induce endothelial cell dysfunction, an early marker for atherosclerosis. In addition, intercellular communication through channels composed of transmembrane connexin proteins (Cxs), i.e. Gap junctions (direct cell-cell coupling) and hemichannels (paracrine release/uptake pathway) can modulate radiation-induced responses and therefore the atherosclerotic process. However, the role of endothelial hemichannel in IR-induced atherosclerosis has never been described before. MATERIALS AND METHODS Telomerase-immortalized human Coronary Artery/Microvascular Endothelial cells (TICAE/TIME) were exposed to X-rays (0.1 and 5 Gy). Production of reactive oxygen species (ROS), DNA damage, cell death, inflammatory responses, and senescence were assessed with or without applying a Cx43 hemichannel blocker (TAT-Gap19). RESULTS We report here that IR induces an increase in oxidative stress, cell death, inflammatory responses (IL-8, IL-1β, VCAM-1, MCP-1, and Endothelin-1) and premature cellular senescence in TICAE and TIME cells. These effects are significantly reduced in the presence of the Cx43 hemichannel-targeting peptide TAT-Gap19. CONCLUSION Our findings suggest that endothelial Cx43 hemichannels contribute to various IR-induced processes, such as ROS, cell death, inflammation, and senescence, resulting in an increase in endothelial cell damage, which could be protected by blocking these hemichannels. Thus, targeting Cx43 hemichannels may potentially exert radioprotective effects.
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Affiliation(s)
- Raghda Ramadan
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
- Department of Fundamental and Basic Medical Sciences, Physiology Group, Ghent University, Ghent, Belgium
| | - Els Vromans
- Centre for Environmental Health Sciences, Hasselt University, Hasselt, Belgium
| | - Dornatien Chuo Anang
- Biomedical Research Institute and Transnational University of Limburg, Hasselt University, Hasselt, Belgium
| | - Ines Goetschalckx
- Protein Chemistry, Proteomics and Epigenetic Signaling Group, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Delphine Hoorelbeke
- Department of Fundamental and Basic Medical Sciences, Physiology Group, Ghent University, Ghent, Belgium
| | - Elke Decrock
- Department of Fundamental and Basic Medical Sciences, Physiology Group, Ghent University, Ghent, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
- Department of Molecular Biotechnology, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Department of Fundamental and Basic Medical Sciences, Physiology Group, Ghent University, Ghent, Belgium
| | - An Aerts
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
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Figueroa VA, Jara O, Oliva CA, Ezquer M, Ezquer F, Retamal MA, Martínez AD, Altenberg GA, Vargas AA. Contribution of Connexin Hemichannels to the Decreases in Cell Viability Induced by Linoleic Acid in the Human Lens Epithelial Cells (HLE-B3). Front Physiol 2020; 10:1574. [PMID: 32038277 PMCID: PMC6984129 DOI: 10.3389/fphys.2019.01574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 12/16/2019] [Indexed: 01/16/2023] Open
Abstract
Connexin (Cx) proteins form gap junction channels (GJC) and hemichannels that a allow bidirectional flow of ions and metabolites between the cytoplasm and extracellular space, respectively. Under physiological conditions, hemichannels have a very low probability of opening, but in certain pathologies, hemichannels activity can increase and induce and/or accelerate cell death. Several mechanisms control hemichannels activity, including phosphorylation and oxidation (i.e., S-nitrosylation). Recently, the effect of polyunsaturated fatty acids (PUFAs) such as linoleic acid (LA), were found to modulate Cxs. It has been seen that LA increase cell death in bovine and human lens cells. The lens is a structure allocated in the eye that highly depends on Cx for the metabolic coupling between its cells, a condition necessary for its transparency. Therefore, we hypothesized that LA induces lens cells death by modulating hemichannel activity. In this work, we characterized the effect of LA on hemichannel activity and survival of HLE-B3 cells (a human lens epithelial cell line). We found that HLE-B3 cells expresses Cx43, Cx46, and Cx50 and can form functional hemichannels in their plasma membrane. The extracellular exposure to 10–50 μM of LA increases hemichannels activity (dye uptake) in a concentration-dependent manner, which was reduced by Cx-channel blockers, such as the Cx-mimetic peptide Gap27 and TATGap19, La3+, carbenoxolone (CBX) and the Akt kinase inhibitor. Additionally, LA increases intracellular calcium, which is attenuated in the presence of TATGap19, a specific Cx43-hemichannel inhibitor. Finally, the long exposure of HLE-B3 cells to LA 20 and 50 μM, reduced cell viability, which was prevented by CBX. Moreover, LA increased the proportion of apoptotic HLE-B3 cells, effect that was prevented by the Cx-mimetic peptide TAT-Gap19 but not by Akt inhibitor. Altogether, these findings strongly suggest a contribution of hemichannels opening in the cell death induced by LA in HLE-B3 cells. These cells can be an excellent tool to develop pharmacological studies in vitro.
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Affiliation(s)
- Vania A Figueroa
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.,Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile
| | - Oscar Jara
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
| | - Carolina A Oliva
- Centro de Envejecimiento y Regeneración (CARE-UC), Departamento Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Marcelo Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Fernando Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Mauricio A Retamal
- Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Facultad de Medicina Clínica Alemana, Santiago, Chile.,Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Aníbal A Vargas
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile.,Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Lissoni A, Hulpiau P, Martins-Marques T, Wang N, Bultynck G, Schulz R, Witschas K, Girao H, De Smet M, Leybaert L. RyR2 regulates Cx43 hemichannel intracellular Ca2+-dependent activation in cardiomyocytes. Cardiovasc Res 2019; 117:123-136. [PMID: 31841141 DOI: 10.1093/cvr/cvz340] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/14/2019] [Accepted: 12/11/2019] [Indexed: 12/16/2022] Open
Abstract
AIMS Connexin-based gap junctions are crucial for electrical communication in the heart; they are each composed of two docked hemichannels (HCs), supplied as unpaired channels via the sarcolemma. When open, an unpaired HC forms a large pore, high-conductance and Ca2+-permeable membrane shunt pathway that may disturb cardiomyocyte function. HCs composed of connexin 43 (Cx43), a major cardiac connexin, can be opened by electrical stimulation but only by very positive membrane potentials. Here, we investigated the activation of Cx43 HCs in murine ventricular cardiomyocytes voltage-clamped at -70 mV. METHODS AND RESULTS Using whole-cell patch-clamp, co-immunoprecipitation, western blot analysis, immunocytochemistry, proximity ligation assays, and protein docking studies, we found that stimulation of ryanodine receptors (RyRs) triggered unitary currents with a single-channel conductance of ∼220 pS, which were strongly reduced by Cx43 knockdown. Recordings under Ca2+-clamp conditions showed that both RyR activation and intracellular Ca2+ elevation were necessary for HC opening. Proximity ligation studies indicated close Cx43-RyR2 apposition (<40 nm), and both proteins co-immunoprecipitated indicating physical interaction. Molecular modelling suggested a strongly conserved RyR-mimicking peptide sequence (RyRHCIp), which inhibited RyR/Ca2+ HC activation but not voltage-triggered activation. The peptide also slowed down action potential repolarization. Interestingly, alterations in the concerned RyR sequence are known to be associated with primary familial hypertrophic cardiomyopathy. CONCLUSION Our results demonstrate that Cx43 HCs are intimately linked to RyRs, allowing them to open at negative diastolic membrane potential in response to RyR activation.
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Affiliation(s)
- Alessio Lissoni
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent 9000, Belgium
| | - Paco Hulpiau
- Department of Bio-Medical Sciences, HOWEST University of Applied Sciences (Hogeschool West-Vlaanderen), Bruges, Belgium
| | - Tânia Martins-Marques
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal
| | - Nan Wang
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent 9000, Belgium
| | - Geert Bultynck
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, KU Leuven, Leuven, Belgium
| | - Rainer Schulz
- Institut für Physiologie, JustusLiebig Universität Giessen, Giessen, Germany
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent 9000, Belgium
| | - Henrique Girao
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal
| | - Maarten De Smet
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent 9000, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent 9000, Belgium
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Delvaeye T, De Smet MAJ, Verwaerde S, Decrock E, Czekaj A, Vandenbroucke RE, Lemeire K, Gonçalves A, Declercq W, Vandenabeele P, Krysko DV, Leybaert L. Blocking connexin43 hemichannels protects mice against tumour necrosis factor-induced inflammatory shock. Sci Rep 2019; 9:16623. [PMID: 31719598 PMCID: PMC6851386 DOI: 10.1038/s41598-019-52900-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
Upon intravenous injection of tumour necrosis factor (TNF) in mice, a systemic inflammatory response syndrome (SIRS) is initiated, characterized by an acute cytokine storm and induction of vascular hyperpermeability. Connexin43 hemichannels have been implicated in various pathological conditions, e.g. ischemia and inflammation, and can lead to detrimental cellular outcomes. Here, we explored whether targeting connexin43 hemichannels could alleviate TNF-induced endothelial barrier dysfunction and lethality in SIRS. Therefore, we verified whether administration of connexin43-targeting-peptides affected survival, body temperature and vascular permeability in vivo. In vitro, TNF-effects on connexin43 hemichannel function were investigated by single-channel studies and Ca2+-imaging. Blocking connexin43 hemichannels with TAT-Gap19 protected mice against TNF-induced mortality, hypothermia and vascular leakage, while enhancing connexin43 hemichannel function with TAT-CT9 provoked opposite sensitizing effects. In vitro patch-clamp studies revealed that TNF acutely activated connexin43 hemichannel opening in endothelial cells, which was promoted by CT9, and inhibited by Gap19 and intracellular Ca2+-buffering. In vivo experiments aimed at buffering intracellular Ca2+, and pharmacologically targeting Ca2+/calmodulin-dependent protein kinase-II, a known modulator of endothelial barrier integrity, demonstrated their involvement in permeability alterations. Our results demonstrate significant benefits of inhibiting connexin43 hemichannels to counteract TNF-induced SIRS-associated vascular permeability and lethality.
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Affiliation(s)
- Tinneke Delvaeye
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Maarten A J De Smet
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Stijn Verwaerde
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Elke Decrock
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Aleksandra Czekaj
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Roosmarijn E Vandenbroucke
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kelly Lemeire
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Amanda Gonçalves
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,VIB BioImaging Core, Ghent, Belgium
| | - Wim Declercq
- VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Peter Vandenabeele
- VIB Center for Inflammation Research, Ghent, Belgium. .,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium. .,Methusalem Program, Ghent University, Ghent, Belgium.
| | - Dmitri V Krysko
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium.
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium.
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Jiang J, Hoagland D, Palatinus JA, He H, Iyyathurai J, Jourdan LJ, Bultynck G, Wang Z, Zhang Z, Schey K, Poelzing S, McGowan FX, Gourdie RG. Interaction of α Carboxyl Terminus 1 Peptide With the Connexin 43 Carboxyl Terminus Preserves Left Ventricular Function After Ischemia-Reperfusion Injury. J Am Heart Assoc 2019; 8:e012385. [PMID: 31422747 PMCID: PMC6759879 DOI: 10.1161/jaha.119.012385] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background α Carboxyl terminus 1 (αCT1) is a 25–amino acid therapeutic peptide incorporating the zonula occludens‐1 (ZO‐1)–binding domain of connexin 43 (Cx43) that is currently in phase 3 clinical testing on chronic wounds. In mice, we reported that αCT1 reduced arrhythmias after cardiac injury, accompanied by increases in protein kinase Cε phosphorylation of Cx43 at serine 368. Herein, we characterize detailed molecular mode of action of αCT1 in mitigating cardiac ischemia‐reperfusion injury. Methods and Results To study αCT1‐mediated increases in phosphorylation of Cx43 at serine 368, we undertook mass spectrometry of protein kinase Cε phosphorylation assay reactants. This indicated potential interaction between negatively charged residues in the αCT1 Asp‐Asp‐Leu‐Glu‐Iso sequence and lysines (Lys345, Lys346) in an α‐helical sequence (helix 2) within the Cx43‐CT. In silico modeling provided further support for this interaction, indicating that αCT1 may interact with both Cx43 and ZO‐1. Using surface plasmon resonance, thermal shift, and phosphorylation assays, we characterized a series of αCT1 variants, identifying peptides that interacted with either ZO‐1–postsynaptic density‐95/disks large/zonula occludens‐1 2 or Cx43‐CT, but with limited or no ability to bind both molecules. Only peptides competent to interact with Cx43‐CT, but not ZO‐1–postsynaptic density‐95/disks large/zonula occludens‐1 2 alone, prompted increased pS368 phosphorylation. Moreover, in an ex vivo mouse model of ischemia‐reperfusion injury, preischemic infusion only with those peptides competent to bind Cx43 preserved ventricular function after ischemia‐reperfusion. Interestingly, a short 9–amino acid variant of αCT1 (αCT11) demonstrated potent cardioprotective effects when infused either before or after ischemic injury. Conclusions Interaction of αCT1 with the Cx43, but not ZO‐1, is correlated with cardioprotection. Pharmacophores targeting Cx43‐CT could provide a translational approach to preserving heart function after ischemic injury.
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Affiliation(s)
- Jingbo Jiang
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Shenzhen Children's Hospital Shenzhen China.,Department of Pediatric Cardiology Guangdong Cardiovascular Institute Guangdong General Hospital Guangdong Academy of Medical Sciences Guangzhou China
| | - Daniel Hoagland
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA
| | - Joseph A Palatinus
- Cedars-Sinai Heart Smidt Institute Cedars-Sinai Medical Center Los Angeles CA
| | - Huamei He
- Department of Anesthesiology and Critical Care Medicine Children's Hospital of Philadelphia and University of Pennsylvania Philadelphia PA
| | - Jegan Iyyathurai
- Department Cellular and Molecular Medicine KU Leuven Laboratory of Molecular and Cellular Signaling Leuven Belgium
| | - L Jane Jourdan
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA
| | - Geert Bultynck
- Department Cellular and Molecular Medicine KU Leuven Laboratory of Molecular and Cellular Signaling Leuven Belgium
| | - Zhen Wang
- Department of Biochemistry Vanderbilt University School of Medicine Nashville TN
| | - Zhiwei Zhang
- Department of Pediatric Cardiology Guangdong Cardiovascular Institute Guangdong General Hospital Guangdong Academy of Medical Sciences Guangzhou China
| | - Kevin Schey
- Department of Biochemistry Vanderbilt University School of Medicine Nashville TN
| | - Steven Poelzing
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Department of Biomedical Engineering and Mechanics Virginia Tech Blacksburg VA
| | - Francis X McGowan
- Department of Anesthesiology and Critical Care Medicine Children's Hospital of Philadelphia and University of Pennsylvania Philadelphia PA
| | - Robert G Gourdie
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Department of Biomedical Engineering and Mechanics Virginia Tech Blacksburg VA
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37
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Díaz EF, Labra VC, Alvear TF, Mellado LA, Inostroza CA, Oyarzún JE, Salgado N, Quintanilla RA, Orellana JA. Connexin 43 hemichannels and pannexin-1 channels contribute to the α-synuclein-induced dysfunction and death of astrocytes. Glia 2019; 67:1598-1619. [PMID: 31033038 DOI: 10.1002/glia.23631] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 01/22/2023]
Abstract
Diverse studies have suggested that cytoplasmic inclusions of misfolded α-synuclein in neuronal and glial cells are main pathological features of different α-synucleinopathies, including Parkinson's disease and dementia with Lewy bodies. Up to now, most studies have focused on the effects of α-synuclein on neurons, whereas the possible alterations of astrocyte functions and neuron-glia crosstalk have received minor attention. Recent evidence indicates that cellular signaling mediated by hemichannels and pannexons is critical for astroglial function and dysfunction. These channels constitute a diffusional route of communication between the cytosol and the extracellular space and during pathological scenarios they may lead to homeostatic disturbances linked to the pathogenesis and progression of different diseases. Here, we found that α-synuclein enhances the opening of connexin 43 (Cx43) hemichannels and pannexin-1 (Panx1) channels in mouse cortical astrocytes. This response was linked to the activation of cytokines, the p38 MAP kinase, the inducible nitric oxide synthase, cyclooxygenase 2, intracellular free Ca2+ concentration ([Ca2+ ]i ), and purinergic and glutamatergic signaling. Relevantly, the α-synuclein-induced opening of hemichannels and pannexons resulted in alterations in [Ca2+ ]i dynamics, nitric oxide (NO) production, gliotransmitter release, mitochondrial morphology, and astrocyte survival. We propose that α-synuclein-mediated opening of astroglial Cx43 hemichannels and Panx1 channels might constitute a novel mechanism involved in the pathogenesis and progression of α-synucleinopathies.
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Affiliation(s)
- Esteban F Díaz
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tanhia F Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis A Mellado
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carla A Inostroza
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan E Oyarzún
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicole Salgado
- Unidad de Microscopía Avanzada UC, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo A Quintanilla
- Escuela de Medicina, Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIAA), Santiago, Chile.,Laboratory of Neurodegenerative Diseases, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Escuela de Medicina, Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes (CIAA), Santiago, Chile
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Calcium-calmodulin gating of a pH-insensitive isoform of connexin43 gap junctions. Biochem J 2019; 476:1137-1148. [PMID: 30910801 DOI: 10.1042/bcj20180912] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/20/2019] [Accepted: 03/22/2019] [Indexed: 12/13/2022]
Abstract
Intracellular protons and calcium ions are two major chemical factors that regulate connexin43 (Cx43) gap junction communication and the synergism or antagonism between pH and Ca2+ has been questioned for decades. To assess the ability of Ca2+ ions to modulate Cx43 junctional conductance (g j) in the absence of pH-sensitivity, patch clamp experiments were performed on Neuroblastoma-2a (N2a) cells or neonatal mouse ventricular myocytes (NMVMs) expressing either full-length Cx43 or the Cx43-M257 (Cx43K258stop) mutant protein, a carboxyl-terminus (CT) truncated version of Cx43 lacking pH-sensitivity. The addition of 1 μM ionomycin to normal calcium saline reduced Cx43 or Cx43-M257 g j to zero within 15 min of perfusion. This response was prevented by Ca2+-free saline or addition of 100 nM calmodulin (CaM) inhibitory peptide to the internal pipette solution. Internal addition of a connexin50 cytoplasmic loop calmodulin-binding domain (CaMBD) mimetic peptide (200 nM) prevented the Ca2+/ionomycin-induced decrease in Cx43 g j, while 100 μM Gap19 peptide had minimal effect. The investigation of the transjunctional voltage (V j) gating properties of NMVM Cx43-M257 gap junctions confirmed the loss of the fast inactivation of Cx43-M257 g j, but also noted the abolishment of the previously reported facilitated recovery of g j from inactivating potentials. We conclude that the distal CT domain of Cx43 contributes to the V j-dependent fast inactivation and facilitated recovery of Cx43 gap junctions, but the Ca2+/CaM-dependent gating mechanism remains intact in its absence. Sequence-specific connexin CaMBD mimetic peptides act by binding Ca2+/CaM non-specifically and the Cx43 mimetic Gap19 peptide has negligible effect on this chemical gating mechanism.
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Kerkhofs M, Bultynck G, Vervliet T, Monaco G. Therapeutic implications of novel peptides targeting ER-mitochondria Ca 2+-flux systems. Drug Discov Today 2019; 24:1092-1103. [PMID: 30910738 DOI: 10.1016/j.drudis.2019.03.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/16/2019] [Accepted: 03/18/2019] [Indexed: 01/03/2023]
Abstract
Intracellular Ca2+-flux systems located at the ER-mitochondrial axis govern mitochondrial Ca2+ balance and cell fate. Multiple yet incurable pathologies are characterized by insufficient or excessive Ca2+ fluxes toward the mitochondria, in turn leading to aberrant cell life or death dynamics. The discovery and ongoing molecular characterization of the main interorganellar Ca2+ gateways have resulted in a novel class of peptide tools able to regulate relevant protein-protein interactions (PPIs) underlying this signaling scenario. Here, we review peptides, molecularly derived from Ca2+-flux systems or their accessory proteins. We discuss how they alter Ca2+-signaling protein complexes and modulate cell survival in light of their forthcoming therapeutic applications.
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Affiliation(s)
- Martijn Kerkhofs
- KU Leuven, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Laboratory of Molecular and Cellular Signaling, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, 3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Laboratory of Molecular and Cellular Signaling, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, 3000 Leuven, Belgium.
| | - Tim Vervliet
- KU Leuven, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Laboratory of Molecular and Cellular Signaling, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, 3000 Leuven, Belgium
| | - Giovanni Monaco
- KU Leuven, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Laboratory of Molecular and Cellular Signaling, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, 3000 Leuven, Belgium.
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Freitas-Andrade M, Wang N, Bechberger JF, De Bock M, Lampe PD, Leybaert L, Naus CC. Targeting MAPK phosphorylation of Connexin43 provides neuroprotection in stroke. J Exp Med 2019; 216:916-935. [PMID: 30872361 PMCID: PMC6446879 DOI: 10.1084/jem.20171452] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 03/31/2018] [Accepted: 02/08/2019] [Indexed: 12/13/2022] Open
Abstract
This study demonstrates that astrocytic connexin43 gap junction hemichannels are largely controlled by four C-terminal tail–located serine residues and provides mechanistic insight on how phosphorylation of these residues affects recovery from stroke. Connexin43 (Cx43) function is influenced by kinases that phosphorylate specific serine sites located near its C-terminus. Stroke is a powerful inducer of kinase activity, but its effect on Cx43 is unknown. We investigated the impact of wild-type (WT) and knock-in Cx43 with serine to alanine mutations at the protein kinase C (PKC) site Cx43S368A, the casein kinase 1 (CK1) sites Cx43S325A/328Y/330A, and the mitogen-activated protein kinase (MAPK) sites Cx43S255/262/279/282A (MK4) on a permanent middle cerebral artery occlusion (pMCAO) stroke model. We demonstrate that MK4 transgenic animals exhibit a significant decrease in infarct volume that was associated with improvement in behavioral performance. An increase in astrocyte reactivity with a concomitant decrease in microglial reactivity was observed in MK4 mice. In contrast to WT, MK4 astrocytes displayed reduced Cx43 hemichannel activity. Pharmacological blockade of Cx43 hemichannels with TAT-Gap19 also significantly decreased infarct volume in WT animals. This study provides novel molecular insights and charts new avenues for therapeutic intervention associated with Cx43 function.
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Affiliation(s)
- Moises Freitas-Andrade
- Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nan Wang
- Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - John F Bechberger
- Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marijke De Bock
- Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Luc Leybaert
- Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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41
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Giaume C, Sáez JC, Song W, Leybaert L, Naus CC. Connexins and pannexins in Alzheimer’s disease. Neurosci Lett 2019; 695:100-105. [DOI: 10.1016/j.neulet.2017.09.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 08/14/2017] [Accepted: 09/01/2017] [Indexed: 12/22/2022]
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The Role of Connexin-43 in the Inflammatory Process: A New Potential Therapy to Influence Keratitis. J Ophthalmol 2019; 2019:9312827. [PMID: 30805212 PMCID: PMC6360563 DOI: 10.1155/2019/9312827] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/12/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022] Open
Abstract
The studies outlined in this review highlight the relationship between inflammatory signaling molecules and connexin-43 (Cx43). Gap junction (GJ) channels and hemichannels (HCs) participate in the metabolic activity between intra- and extracellular space. Some ions and small molecules are exchanged from cell to cell or cell to extracellular space to affect the process of inflammation via GJ. We analyzed the effects of signaling molecules, such as innate immunity messengers, transcription factors, LPS, cytokine, inflammatory chemokines, and MMPs, on Cx43 expression during the inflammatory process. At the same time, we found that these signaling molecules play a critical role in the pathogenesis of keratitis. Thus, we assessed the function of Cx43 during inflammatory corneal disease. Corneal healing plays an essential role in the late stage of keratitis. We found that Cx43 is involved in wound healing. Studies have shown that the decrease of Cx43 can decrease the time of healing. We also report several Cx43 mimic peptides which can inhibit the activity of Cx43 Hc to mediate the releasing of adenosine triphosphate (ATP), which may in turn influence the inflammatory process.
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43
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Therapeutic Targeting of Connexin Channels: New Views and Challenges. Trends Mol Med 2018; 24:1036-1053. [PMID: 30424929 DOI: 10.1016/j.molmed.2018.10.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/09/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022]
Abstract
Connexins, in particular connexin 43 (Cx43), function as gap junction channels (GJCs) and hemichannels (HCs). Only recently, specific tools have been developed to study their pleiotropic functions. Based on various protein interaction sites, distinct connexin-mimetic peptides have been established that enable discrimination between the function of HCs and GJCs. Although the precise mechanism of action of most of these peptides is still a matter of debate, an increasing number of studies report on important effects of those compounds in disease models. In this review, we summarize the structure, life cycle, and the most important physiological and pathological functions of both connexin GJCs and HCs. We provide a critical overview on the use of connexin-targeting peptides, in particular targeting Cx43, with a special focus on the remaining questions and hurdles to be taken in the research field of connexin channels.
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44
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Sáez JC, Contreras-Duarte S, Gómez GI, Labra VC, Santibañez CA, Gajardo-Gómez R, Avendaño BC, Díaz EF, Montero TD, Velarde V, Orellana JA. Connexin 43 Hemichannel Activity Promoted by Pro-Inflammatory Cytokines and High Glucose Alters Endothelial Cell Function. Front Immunol 2018; 9:1899. [PMID: 30158937 PMCID: PMC6104120 DOI: 10.3389/fimmu.2018.01899] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The present work was done to elucidate whether hemichannels of a cell line derived from endothelial cells are affected by pro-inflammatory conditions (high glucose and IL-1β/TNF-α) known to lead to vascular dysfunction. We used EAhy 926 cells treated with high glucose and IL-1β/TNF-α. The hemichannel activity was evaluated with the dye uptake method and was abrogated with selective inhibitors or knocking down of hemichannel protein subunits with siRNA. Western blot analysis, cell surface biotinylation, and confocal microscopy were used to evaluate total and plasma membrane amounts of specific proteins and their cellular distribution, respectively. Changes in intracellular Ca2+ and nitric oxide (NO) signals were estimated by measuring FURA-2 and DAF-FM probes, respectively. High glucose concentration was found to elevate dye uptake, a response that was enhanced by IL-1β/TNF-α. High glucose plus IL-1β/TNF-α-induced dye uptake was abrogated by connexin 43 (Cx43) but not pannexin1 knockdown. Furthermore, Cx43 hemichannel activity was associated with enhanced ATP release and activation of p38 MAPK, inducible NO synthase, COX2, PGE2 receptor EP1, and P2X7/P2Y1 receptors. Inhibition of the above pathways prevented completely the increase in Cx43 hemichannel activity of cells treated high glucose and IL-1β/TNF-α. Both synthetic and endogenous cannabinoids (CBs) also prevented the increment in Cx43 hemichannel opening, as well as the subsequent generation and release of ATP and NO induced by pro-inflammatory conditions. The counteracting action of CBs also was extended to other endothelial alterations evoked by IL-1β/TNF-α and high glucose, including increased ATP-dependent Ca2+ dynamics and insulin-induced NO production. Finally, inhibition of Cx43 hemichannels also prevented the ATP release from endothelial cells treated with IL-1β/TNF-α and high glucose. Therefore, we propose that reduction of hemichannel activity could represent a strategy against the activation of deleterious pathways that lead to endothelial dysfunction and possibly cell damage evoked by high glucose and pro-inflammatory conditions during cardiovascular diseases.
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Affiliation(s)
- Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Susana Contreras-Duarte
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile.,Departamento de Ginecología y Obstetricia, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I Gómez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Valeria C Labra
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Cristian A Santibañez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rosario Gajardo-Gómez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Beatriz C Avendaño
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esteban F Díaz
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Trinidad D Montero
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Victoria Velarde
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Hoorelbeke D, Decrock E, Van Haver V, De Bock M, Leybaert L. Calcium, a pivotal player in photodynamic therapy? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1805-1814. [PMID: 30076858 DOI: 10.1016/j.bbamcr.2018.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/28/2018] [Accepted: 07/30/2018] [Indexed: 02/06/2023]
Abstract
Photodynamic therapy combines three non-toxic components: light, oxygen and a photosensitizer to generate singlet oxygen and/or other ROS molecules in order to target destruction of cancer cells. The damage induced in the targeted cells can furthermore propagate to non-exposed bystander cells thereby exacerbating the damage. Ca2+ signaling is strongly intertwined with ROS signaling and both play crucial roles in cell death. In this review we aimed to review current knowledge on the role of Ca2+ and ROS signaling, their effect on cell-cell propagation via connexin-linked mechanisms and the outcome in terms of cell death. In general, photodynamic therapy results in an increased cytosolic Ca2+ concentration originating from Ca2+ entry or Ca2+ release from internal stores. While photodynamic therapy can certainly induce cell death, the outcome depends on the cell type and the photosensitizer used. Connexin channels propagating the Ca2+ signal, and presumably regenerating ROS at distance, may play a role in spreading the effect to neighboring non-exposed bystander cells. Given the various cell types and photosensitizers used, there is currently no unified signaling scheme to explain the role of Ca2+ and connexins in the responses following photodynamic therapy. This article is part of a Special Issue entitled: Calcium signaling in health, disease and therapy edited by Geert Bultynck and Jan Parys.
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Affiliation(s)
| | - Elke Decrock
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Valérie Van Haver
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Marijke De Bock
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium
| | - Luc Leybaert
- Physiology group, Dept. of Basic Medical Sciences, UGent, Ghent, Belgium.
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46
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Iyyathurai J, Wang N, D'hondt C, Jiang JX, Leybaert L, Bultynck G. The SH3-binding domain of Cx43 participates in loop/tail interactions critical for Cx43-hemichannel activity. Cell Mol Life Sci 2018; 75:2059-2073. [PMID: 29218600 PMCID: PMC6318120 DOI: 10.1007/s00018-017-2722-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/19/2022]
Abstract
Connexin 43 (Cx43) hemichannels establish local signaling networks via the release of ATP and other molecules, but their excessive opening may result in cell death. Hence, the activity of Cx43-hemichannels ought to be critically controlled. This involves interactions between the C-terminal tail (CT) and the cytoplasmic loop (CL), more particularly the L2 domain within CL. Previous work revealed an important role for the last nine amino acids of the Cx43 CT by targeting the L2 domain, as these nine amino acids were sufficient to restore the activity of CT-truncated Cx43-hemichannels. However, we discovered that deletion of the last 19 amino acids of the CT only partially lowered the binding to the L2 domain, indicating that a second L2-binding region is present in the CT. We here provide evidence that the SH3-binding domain is another CT region that targets the L2 domain. At the functional level, the SH3-binding domain was able to restore the activity of CT-truncated Cx43-hemichannels and alleviate the inhibition of full-length Cx43-hemichannels by high intracellular Ca2+ concentration ([Ca2+]i) as demonstrated by various approaches including patch clamp studies of unitary Cx43-hemichannel activity. Finally, we show that in full-length Cx43-hemichannels, deletion of either the SH3-binding domain or the CT9 region suppresses the hemichannel activity, while deletion of both domains completely annihilates the hemichannel activity. These results demonstrate that the Cx43 SH3-binding domain, in addition to the CT9 region, critically controls hemichannel activity at high [Ca2+]i, which may be involved in pathological hemichannel opening.
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Affiliation(s)
- Jegan Iyyathurai
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Louvain, Belgium
| | - Nan Wang
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Catheleyne D'hondt
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Louvain, Belgium
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Louvain, Belgium.
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Grek CL, Sheng Z, Naus CC, Sin WC, Gourdie RG, Ghatnekar GG. Novel approach to temozolomide resistance in malignant glioma: connexin43-directed therapeutics. Curr Opin Pharmacol 2018; 41:79-88. [PMID: 29803991 DOI: 10.1016/j.coph.2018.05.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 01/03/2023]
Abstract
Resistance of malignant glioma, including glioblastoma (GBM), to the chemotherapeutic temozolomide (TMZ) remains a key obstacle in treatment strategies. The gap junction protein connexin43 (Cx43) has complex roles in the establishment, progression, and persistence of malignant glioma. Recent findings demonstrate that connexins play an important role in the microenvironment of malignant glioma and that Cx43 is capable of conferring chemotherapeutic resistance to GBM cells. Carboxyl-terminal Cx43 peptidomimetics show therapeutic promise in overcoming TMZ resistance via mechanisms that may include modulating junctional activity between tumor cells and peritumoral cells and/or downstream molecular signaling events mediated by Cx43 protein binding. High levels of intra-tumor and inter-tumor heterogeneity make it difficult to clearly define specific populations for Cx43-targeted therapy; hence, development of in vitro models that better mimic the microenvironment of malignant glioma, and the incorporation of patient-derived stem cells, could provide opportunities for patient-specific drug screening. This review summarizes recent advances in understanding the roles of Cx43 in malignant glioma, with a special focus on tumor microenvironment, TMZ resistance, and therapeutic opportunity offered by Cx43 peptidomimetics.
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Affiliation(s)
| | - Zhi Sheng
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Department of Biological Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA; Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Christian C Naus
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Wun Chey Sin
- Department of Cellular and Physiological Science, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Robert G Gourdie
- Virginia Tech Carilion Research Institute, Roanoke, VA, USA; Faculty of Health Science, Virginia Tech, Blacksburg, VA, USA; Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Blacksburg, VA, USA; Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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48
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Kylmäoja E, Nakamura M, Kokkonen-Puuperä H, Ronkainen VP, Lehenkari P, Tuukkanen J. Gap junctional communication is involved in differentiation of osteoclasts from bone marrow and peripheral blood monocytes. Heliyon 2018; 4:e00621. [PMID: 29756076 PMCID: PMC5944415 DOI: 10.1016/j.heliyon.2018.e00621] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/05/2018] [Accepted: 05/02/2018] [Indexed: 12/22/2022] Open
Abstract
Aims The aim of the study was to compare the influence of gap junctional communication (GJC) in osteoclastogenesis from bone marrow (BM) and peripheral blood (PB) monocytes. These widely used sources differ in purity, since BM cultures contain a significant number of stromal cells. We studied whether stimulation of GJC in BM monocyte/stromal cell cultures differs from the effect in pure PB monocyte cultures. We compared the differentiation also in acidosis, which is a known inducer of bone resorption. Main methods Human BM and PB monocytes were isolated from BM aspirates or whole blood samples. The cells were cultured on human bone slices with osteoclastogenic growth factors and a GJC modulator, antiarrhythmic peptide AAP10, at physiological and acidic pH. Key findings Both BM and PB monocytes differentiated into osteoclasts. Acidosis increased resorption in both cultures but stimulated cell fusion only in BM cultures, which demonstrates the role of stromal cells in osteoclastogenesis. At physiological pH, AAP10 increased the number of multinuclear cells and bone resorption in both BM and PB cultures indicating that GJC is involved in differentiation in both of these osteoclastogenesis assays. Interestingly, in PB cultures at pH 6.5 the stimulation of GJC with AAP10 inhibited both osteoclastogenesis and bone resorption suggesting a different role of GJC in BM and PB monocytes at stressed environment. Significance The study is conducted with primary human tissue samples and adds new knowledge on factors affecting osteoclastogenesis from different monocyte sources.
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Affiliation(s)
- Elina Kylmäoja
- Institute of Cancer Research and Translational Medicine, Department of Anatomy and Cell Biology, Medical Research Center, P.O. Box 5000, 90014, University of Oulu, Finland
- Corresponding author.
| | - Miho Nakamura
- Institute of Cancer Research and Translational Medicine, Department of Anatomy and Cell Biology, Medical Research Center, P.O. Box 5000, 90014, University of Oulu, Finland
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 1010062, Japan
| | - Hanna Kokkonen-Puuperä
- Institute of Cancer Research and Translational Medicine, Department of Anatomy and Cell Biology, Medical Research Center, P.O. Box 5000, 90014, University of Oulu, Finland
| | - Veli-Pekka Ronkainen
- Biocenter Oulu, Light Microscopy Core Facility, P.O. Box 5000, 90014, University of Oulu, Finland
| | - Petri Lehenkari
- Institute of Cancer Research and Translational Medicine, Department of Anatomy and Cell Biology, Medical Research Center, P.O. Box 5000, 90014, University of Oulu, Finland
| | - Juha Tuukkanen
- Institute of Cancer Research and Translational Medicine, Department of Anatomy and Cell Biology, Medical Research Center, P.O. Box 5000, 90014, University of Oulu, Finland
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Conflicting Roles of Connexin43 in Tumor Invasion and Growth in the Central Nervous System. Int J Mol Sci 2018; 19:ijms19041159. [PMID: 29641478 PMCID: PMC5979343 DOI: 10.3390/ijms19041159] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/05/2018] [Accepted: 04/09/2018] [Indexed: 12/24/2022] Open
Abstract
The tumor microenvironment is known to have increased levels of cytokines and metabolites, such as glutamate, due to their release from the surrounding cells. A normal cell around the tumor that responds to the inflammatory environment is likely to be subsequently altered. We discuss how these abnormalities will support tumor survival via the actions of gap junctions (GJs) and hemichannels (HCs) which are composed of hexamer of connexin43 (Cx43) protein. In particular, we discuss how GJ intercellular communication (GJIC) in glioma cells, the primary brain tumor, is a regulatory factor and its attenuation leads to tumor invasion. In contrast, the astrocytes, which are normal cells around the glioma, are “hijacked” by tumor cells, either by receiving the transmission of malignant substances from the cancer cells via GJIC, or perhaps via astrocytic HC activity through the paracrine signaling which enable the delivery of these substances to the distal astrocytes. This astrocytic signaling would promote tumor expansion in the brain. In addition, brain metastasis from peripheral tissues has also been known to be facilitated by GJs formed between cerebral vascular endothelial cells and cancer cells. Astrocytes and microglia are generally thought to eliminate cancer cells at the blood–brain barrier. In contrast, some reports suggest they facilitate tumor progression as tumor cells take advantage of the normal functions of astrocytes that support the survival of the neurons by exchanging nutrients and metabolites. In summary, GJIC is essential for the normal physiological function of growth and allowing the diffusion of physiological substances. Therefore, whether GJIC is cancer promoting or suppressing may be dependent on what permeates through GJs, when it is active, and to which cells. The nature of GJs, which has been ambiguous in brain tumor progression, needs to be revisited and understood together with new findings on Cx proteins and HC activities.
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Carrer A, Leparulo A, Crispino G, Ciubotaru CD, Marin O, Zonta F, Bortolozzi M. Cx32 hemichannel opening by cytosolic Ca2+ is inhibited by the R220X mutation that causes Charcot-Marie-Tooth disease. Hum Mol Genet 2018; 27:80-94. [PMID: 29077882 DOI: 10.1093/hmg/ddx386] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/17/2017] [Indexed: 11/15/2022] Open
Abstract
Mutations of the GJB1 gene encoding connexin 32 (Cx32) cause the X-linked form of Charcot-Marie-Tooth disease (CMTX1), a demyelinating peripheral neuropathy for which there is no cure. A growing body of evidence indicates that ATP release through Cx32 hemichannels in Schwann cells could be critical for nerve myelination, but it is unknown if CMTX1 mutations alter the cytosolic Ca2+-dependent gating mechanism that controls Cx32 hemichannel opening and ATP release. The current study uncovered that loss of the C-terminus in Cx32 (R220X mutation), which causes a severe CMTX1 phenotype, inhibits hemichannel opening during a canonical IP3-mediated increase in cytosolic Ca2+ in HeLa cells. Interestingly, the gating function of R220X hemichannels was completely restored by both the intracellular and extracellular application of a peptide that mimics the Cx32 cytoplasmic loop. All-atom molecular dynamics simulations suggest that loss of the C-terminus in the mutant hemichannel triggers abnormal fluctuations of the cytoplasmic loop which are prevented by binding to the mimetic peptide. Experiments that stimulated R220X hemichannel opening by cell depolarization displayed reduced voltage sensitivity with respect to wild-type hemichannels which was explained by loss of subconductance states at the single channel level. Finally, experiments of intercellular diffusion mediated by wild-type or R220X gap junction channels revealed similar unitary permeabilities to ions, signalling molecules (cAMP) or larger solutes (Lucifer yellow). Taken together, our findings support the hypothesis that paracrine signalling alteration due to Cx32 hemichannel dysfunction underlies CMTX1 pathogenesis and suggest a candidate molecule for novel studies investigating a therapeutic approach.
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Affiliation(s)
- Andrea Carrer
- Venetian Institute of Molecular Medicine (VIMM), Padua 35129, Italy
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padua 35131, Italy
| | - Alessandro Leparulo
- Venetian Institute of Molecular Medicine (VIMM), Padua 35129, Italy
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padua 35131, Italy
| | - Giulia Crispino
- Venetian Institute of Molecular Medicine (VIMM), Padua 35129, Italy
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padua 35131, Italy
| | | | - Oriano Marin
- Department of Biomedical Sciences, University of Padua, Padua 35131, Italy
| | - Francesco Zonta
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
- Italian National Research Council (CNR), Institute of Cell Biology and Neurobiology, Monterotondo 00015, Italy
| | - Mario Bortolozzi
- Venetian Institute of Molecular Medicine (VIMM), Padua 35129, Italy
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padua 35131, Italy
- Italian National Research Council (CNR), Institute of Protein Biochemistry, Naples 80131, Italy
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