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Al-attar R, Jargstorf J, Romagnuolo R, Jouni M, Alibhai FJ, Lampe PD, Solan JL, Laflamme MA. Casein Kinase 1 Phosphomimetic Mutations Negatively Impact Connexin-43 Gap Junctions in Human Pluripotent Stem Cell-Derived Cardiomyocytes. Biomolecules 2024; 14:61. [PMID: 38254663 PMCID: PMC10813327 DOI: 10.3390/biom14010061] [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: 11/10/2023] [Revised: 12/14/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024] Open
Abstract
The transplantation of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) has shown promise in preclinical models of myocardial infarction, but graft myocardium exhibits incomplete host-graft electromechanical integration and a propensity for pro-arrhythmic behavior. Perhaps contributing to this situation, hPSC-CM grafts show low expression of connexin 43 (Cx43), the major gap junction (GJ) protein, in ventricular myocardia. We hypothesized that Cx43 expression and function could be rescued by engineering Cx43 in hPSC-CMs with a series of phosphatase-resistant mutations at three casein kinase 1 phosphorylation sites (Cx43-S3E) that have been previously reported to stabilize Cx43 GJs and reduce arrhythmias in transgenic mice. However, contrary to our predictions, transgenic Cx43-S3E hPSC-CMs exhibited reduced Cx43 expression relative to wild-type cells, both at baseline and following ischemic challenge. Cx43-S3E hPSC-CMs showed correspondingly slower conduction velocities, increased automaticity, and differential expression of other connexin isoforms and various genes involved in cardiac excitation-contraction coupling. Cx43-S3E hPSC-CMs also had phosphorylation marks associated with Cx43 GJ internalization, a finding that may account for their impaired GJ localization. Taken collectively, our data indicate that the Cx43-S3E mutation behaves differently in hPSC-CMs than in adult mouse ventricular myocytes and that multiple biological factors likely need to be addressed synchronously to ensure proper Cx43 expression, localization, and function.
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Affiliation(s)
- Rasha Al-attar
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
| | - Joseph Jargstorf
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
| | - Rocco Romagnuolo
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
| | - Mariam Jouni
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
| | - Faisal J. Alibhai
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
| | - Paul D. Lampe
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (P.D.L.); (J.L.S.)
| | - Joell L. Solan
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (P.D.L.); (J.L.S.)
| | - Michael A. Laflamme
- McEwen Stem Cell Institute, University Health Network, Toronto, ON M5G 1L7, Canada; (R.A.-a.); (J.J.); (R.R.); (M.J.); (F.J.A.)
- Peter Munk Cardiac Centre, University Health Network, Toronto, ON M5G 1L7, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G 1L7, Canada
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Billur D, Olgar Y, Durak A, Yozgat AH, Unay S, Tuncay E, Turan B. An increase in intercellular crosstalk and electrotonic coupling between cardiomyocytes and nonmyocytes reshapes the electrical conduction in the metabolic heart characterized by short QT intervals in ECGs. Cell Biochem Funct 2023; 41:1526-1542. [PMID: 38014767 DOI: 10.1002/cbf.3893] [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: 10/04/2023] [Revised: 11/07/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023]
Abstract
Cardiac conduction abnormalities are disorders in metabolic syndrome (MetS), however, their mechanisms are unknown. Although ventricular arrhythmia reflects the changes in QT-interval of electrocardiograms associated with the changes in cardiomyocyte action potential durations (APDs), recent studies emphasize role of intercellular crosstalk between cardiomyocytes and nonmyocytes via passive (electrotonic)-conduction. Therefore, considering the possible increase in intercellular interactions of nonmyocytes with cardiomyocytes, we hypothesized an early-cardiac-remodeling characterized by short QT-interval via contributions and modulations of changes by nonmyocytes to the ventricular APs in an early-stage MetS hearts. Following the feeding of 8-week-old rats with a high-sucrose diet (32%; MetS rats) and validation of insulin resistance, there was a significant increase in heart rate and changes in the electrical characteristics of the hearts, especially a shortening in action potential (AP) duration of the papillary muscles. The patch-clamp analysis of ventricular cardiomyocytes showed an increase in the Na+ -channel currents while there were decreases in l-type Ca2+ -channel (LTCC) currents with unchanged K+ -channel currents. There was an increase in the phosphorylated form of connexin 43 (pCx43), mostly with lateral localization on sarcolemma, while its unphosphorylated form (Cx43) exhibited a high degree of localization within intercalated discs. A high-level positively-stained α-SMA and CD68 cells were prominently localized and distributed in interfibrillar spaces of the heart, implying the possible contributions of myofibroblasts and macrophages to both shortened APDs and abnormal electrical conduction in MetS hearts. Our data propose a previously unrecognized pathway for SQT induction in the heart. This pathway includes not only the contribution of short ventricular-APDs via ionic mechanisms but also increasing contributions of the electrotonic-cardiomyocyte depolarization, spontaneous electrical activity-associated fast heterogeneous impulse conduction in the heart via increased interactions and relocations between cardiomyocytes and nonmyocytes, which may be an explanation for the development of an SQT in early-cardiac-remodeling.
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Affiliation(s)
- Deniz Billur
- Departments of Histology-Embryology, Faculty of Medicine, Ankara University, Ankara, Türkiye
| | - Yusuf Olgar
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Türkiye
| | - Aysegul Durak
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Türkiye
| | - Ayse Hande Yozgat
- Departments of Histology-Embryology, Faculty of Medicine, Ankara University, Ankara, Türkiye
| | - Simge Unay
- Departments of Biophysics, Lokman Hekim University Faculty of Medicine, Ankara, Türkiye
| | - Erkan Tuncay
- Departments of Biophysics, Faculty of Medicine, Ankara University, Ankara, Türkiye
| | - Belma Turan
- Departments of Biophysics, Lokman Hekim University Faculty of Medicine, Ankara, Türkiye
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Ek-Vitorin JF, Silva-Mendoza D, Pontifex TK, Burt JM. Channel Behavior and Voltage Gating of a Cx43 Mutant Simulating Preconditioning. Bioelectricity 2023; 5:181-187. [PMID: 37746309 PMCID: PMC10516231 DOI: 10.1089/bioe.2023.0024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023] Open
Abstract
Background Ischemic preconditioning induces lateralization and dephosphorylation of Connexin 43 (Cx43). However, the Cx43 protein that remains at intercalated disks may be phosphorylated by casein kinase 1 (CK1) and protein kinase C (PKC), and both kinases provide cardioprotection from further ischemic injury. Here we explore the channel characteristics of a Cx43 mutant mimicking preconditioning by CK1 and PKC phosphorylation. Materials and Methods Whole-cell patch-clamp recordings were performed in cells expressing the mutant Cx43pc (S325,328,330,368D, S365A-Cx43), and the connexin electrical behavior was analyzed at the single channel and macroscopic level. Results Cx43pc hemichannels opened readily, whereas gap junctions channels displayed amplitudes between the wild-type and CK1 phosphorylated forms, and weaker voltage gating than either counterpart. Conclusions Ischemic preconditioning and the ensuing phosphorylation of Cx43 by PKC may render junctional channels insensitive to transjunctional voltages, allowing the preservation of intercellular communication in ischemic conditions.
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Affiliation(s)
| | | | - Tasha K. Pontifex
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
| | - Janis M. Burt
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
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Deng Z, Richardson DR. The Myc Family and the Metastasis Suppressor NDRG1: Targeting Key Molecular Interactions with Innovative Therapeutics. Pharmacol Rev 2023; 75:1007-1035. [PMID: 37280098 DOI: 10.1124/pharmrev.122.000795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/07/2023] [Accepted: 05/01/2023] [Indexed: 06/08/2023] Open
Abstract
Cancer is a leading cause of death worldwide, resulting in ∼10 million deaths in 2020. Major oncogenic effectors are the Myc proto-oncogene family, which consists of three members including c-Myc, N-Myc, and L-Myc. As a pertinent example of the role of the Myc family in tumorigenesis, amplification of MYCN in childhood neuroblastoma strongly correlates with poor patient prognosis. Complexes between Myc oncoproteins and their partners such as hypoxia-inducible factor-1α and Myc-associated protein X (MAX) result in proliferation arrest and pro-proliferative effects, respectively. Interactions with other proteins are also important for N-Myc activity. For instance, the enhancer of zest homolog 2 (EZH2) binds directly to N-Myc to stabilize it by acting as a competitor against the ubiquitin ligase, SCFFBXW7, which prevents proteasomal degradation. Heat shock protein 90 may also be involved in N-Myc stabilization since it binds to EZH2 and prevents its degradation. N-Myc downstream-regulated gene 1 (NDRG1) is downregulated by N-Myc and participates in the regulation of cellular proliferation via associating with other proteins, such as glycogen synthase kinase-3β and low-density lipoprotein receptor-related protein 6. These molecular interactions provide a better understanding of the biologic roles of N-Myc and NDRG1, which can be potentially used as therapeutic targets. In addition to directly targeting these proteins, disrupting their key interactions may also be a promising strategy for anti-cancer drug development. This review examines the interactions between the Myc proteins and other molecules, with a special focus on the relationship between N-Myc and NDRG1 and possible therapeutic interventions. SIGNIFICANCE STATEMENT: Neuroblastoma is one of the most common childhood solid tumors, with a dismal five-year survival rate. This problem makes it imperative to discover new and more effective therapeutics. The molecular interactions between major oncogenic drivers of the Myc family and other key proteins; for example, the metastasis suppressor, NDRG1, may potentially be used as targets for anti-neuroblastoma drug development. In addition to directly targeting these proteins, disrupting their key molecular interactions may also be promising for drug discovery.
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Affiliation(s)
- Zhao Deng
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia (Z.D., D.R.R.), and Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, Japan (D.R.R.)
| | - Des R Richardson
- Centre for Cancer Cell Biology and Drug Discovery, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia (Z.D., D.R.R.), and Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, Japan (D.R.R.)
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Wang T, Liu J, Hu C, Wei X, Han L, Zhu A, Wang R, Chen Z, Xia Z, Yao S, Mao W. Downregulation of cardiac PIASy inhibits Cx43 SUMOylation and ameliorates ventricular arrhythmias in a rat model of myocardial ischemia/reperfusion injury. Chin Med J (Engl) 2023; 136:1349-1357. [PMID: 37014755 PMCID: PMC10309519 DOI: 10.1097/cm9.0000000000002618] [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: 12/19/2022] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Dysfunction of the gap junction channel protein connexin 43 (Cx43) contributes to myocardial ischemia/reperfusion (I/R)-induced ventricular arrhythmias. Cx43 can be regulated by small ubiquitin-like modifier (SUMO) modification. Protein inhibitor of activated STAT Y (PIASy) is an E3 SUMO ligase for its target proteins. However, whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown. METHODS Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid (shRNA) using recombinant adeno-associated virus subtype 9 (rAAV9). Two weeks later, the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion. Electrocardiogram was recorded to assess arrhythmias. Rat ventricular tissues were collected for molecular biological measurements. RESULTS Following 45 min of ischemia, QRS duration and QTc intervals statistically significantly increased, but these values decreased after transfecting PIASy shRNA. PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R, as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation, and reduced arrythmia score. In addition, myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation, accompanied by reduced Cx43 phosphorylation and plakophilin 2 (PKP2) expression. Moreover, PIASy downregulation remarkably reduced Cx43 SUMOylation, accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R. CONCLUSION PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression, thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.
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Affiliation(s)
- Tingting Wang
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Jinmin Liu
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
- Department of Anesthesiology, Wuhan No. 1 Hospital, Wuhan, Hubei 430022, China
| | - Chenchen Hu
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Xin Wei
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Linlin Han
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Afang Zhu
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Rong Wang
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Zhijun Chen
- Department of Anesthesiology, Wuhan No. 1 Hospital, Wuhan, Hubei 430022, China
| | - Zhengyuan Xia
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Medicine, The University of Hong Kong, Hong Kong, China
| | - Shanglong Yao
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Weike Mao
- Department of Anesthesiology, Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
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Jiang H, Zhang Y, Wang ZZ, Chen NH. Connexin 43: An Interface Connecting Neuroinflammation to Depression. Molecules 2023; 28:molecules28041820. [PMID: 36838809 PMCID: PMC9961786 DOI: 10.3390/molecules28041820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Major depressive disorder (MDD) is a leading chronic mental illness worldwide, characterized by anhedonia, pessimism and even suicidal thoughts. Connexin 43 (Cx43), mainly distributed in astrocytes of the brain, is by far the most widely and ubiquitously expressed connexin in almost all vital organs. Cx43 forms gap junction channels in the brain, which mediate energy exchange and effectively maintain physiological homeostasis. Increasing evidence suggests the crucial role of Cx43 in the pathogenesis of MDD. Neuroinflammation is one of the most common pathological features of the central nervous system dysfunctions. Inflammatory factors are abnormally elevated in patients with depression and are closely related to nearly all links of depression. After activating the inflammatory pathway in the brain, the release and uptake of glutamate and adenosine triphosphate, through Cx43 in the synaptic cleft, would be affected. In this review, we have summarized the association between Cx43 and neuroinflammation, the cornerstones linking inflammation and depression, and Cx43 abnormalities in depression. We also discuss the significant association of Cx43 in inflammation and depression, which will help to explore new antidepressant drug targets.
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Affiliation(s)
- Hong Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
| | - Yi Zhang
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
- Correspondence: (Z.-Z.W.); (N.-H.C.); Tel.: +86-10-6316-5182 (Z.-Z.W.); +86-10-63165177 (N.-H.C.)
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical, Science and Peking Union Medical College, Beijing 100050, China
- Correspondence: (Z.-Z.W.); (N.-H.C.); Tel.: +86-10-6316-5182 (Z.-Z.W.); +86-10-63165177 (N.-H.C.)
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Fu ZP, Wu LL, Xue JY, Zhang LE, Li C, You HJ, Luo DL. Connexin 43 hyper-phosphorylation at serine 282 triggers apoptosis in rat cardiomyocytes via activation of mitochondrial apoptotic pathway. Acta Pharmacol Sin 2022; 43:1970-1978. [PMID: 34931018 PMCID: PMC9343349 DOI: 10.1038/s41401-021-00824-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/16/2021] [Indexed: 12/12/2022] Open
Abstract
Cx43 is the major connexin in ventricular gap junctions, and plays a pivotal role in control of electrical and metabolic communication among adjacent cardiomyocytes. We previously found that Cx43 dephosphorylation at serine 282 (pS282) caused cardiomyocyte apoptosis, which is involved in cardiac ischemia/reperfusion injury. In this study we investigated whether Cx43-S282 hyper-phosphorylation could protect cardiomyocytes against apoptosis. Adenovirus carrying rat full length Cx43 gene (Cx43-wt) or a mutant gene at S282 substituted with aspartic acid (S282D) were transfected into neonatal rat ventricular myocytes (NRVMs) or injected into rat ventricular wall. Rat abdominal aorta constriction model (AAC) was used to assess Cx43-S282 phosphorylation status. We showed that Cx43 phosphorylation at S282 was increased over 2-times compared to Cx43-wt cells at 24 h after transfection, while pS262 and pS368 were unaltered. S282D-transfected cells displayed enhanced gap junctional communication, and increased basal intracellular Ca2+ concentration and spontaneous Ca2+ transients compared to Cx43-wt cells. However, spontaneous apoptosis appeared in NRVMs transfected with S282D for 34 h. Rat ventricular myocardium transfected with S282D in vivo also exhibited apoptotic responses, including increased Bax/Bcl-xL ratio, cytochrome c release as well as caspase-3 and caspase-9 activities, while factor-associated suicide (Fas)/Fas-associated death domain expression and caspase-8 activity remained unaltered. In addition, AAC-induced hypertrophic ventricles had apoptotic injury with Cx43-S282 hyper-phosphorylation compared with Sham ventricles. In conclusion, Cx43 hyper-phosphorylation at S282, as dephosphorylation, also triggers cardiomyocyte apoptosis, but through activation of mitochondrial apoptosis pathway, providing a fine-tuned Cx43-S282 phosphorylation range required for the maintenance of cardiomyocyte function and survival.
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Affiliation(s)
- Zhi-ping Fu
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Lu-lin Wu
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Jing-yi Xue
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Lan-e Zhang
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Chen Li
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Hong-jie You
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
| | - Da-li Luo
- grid.24696.3f0000 0004 0369 153XDepartment of Pharmacology, School of Basic Medical Sciences, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, Capital Medical University, Beijing, 100069 China
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Shimura D, Shaw RM. GJA1-20k and Mitochondrial Dynamics. Front Physiol 2022; 13:867358. [PMID: 35399255 PMCID: PMC8983841 DOI: 10.3389/fphys.2022.867358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/08/2022] [Indexed: 01/07/2023] Open
Abstract
Connexin 43 (Cx43) is the primary gap junction protein of mammalian heart ventricles and is encoded by the gene Gja1 which has a single coding exon and therefore cannot be spliced. We previously identified that Gja1 mRNA undergoes endogenous internal translation initiated at one of several internal AUG (M) start codons, generating N-terminal truncated protein isoforms that retain the C-terminus distal to the start site. GJA1-20k, whose translation initiates at mRNA M213, is usually the most abundant isoform in cells and greatly increases after ischemic and metabolic stress. GJA1-20k consists of a small segment of the last transmembrane domain and the complete C-terminus tail of Cx43, with a total size of about 20 kDa. The original role identified for GJA1-20k is as an essential subunit that facilitates the trafficking of full-length Cx43 hexameric hemichannels to cell-cell contacts, generating traditional gap junctions between adjacent cells facilitating, in cardiac muscle, efficient spread of electrical excitation. GJA1-20k deficient mice (generated by a M213L substitution in Gja1) suffer poor electrical coupling between cardiomycytes and arrhythmogenic sudden death two to 4 weeks after their birth. We recently identified that exogenous GJA1-20k expression also mimics the effect of ischemic preconditioning in mouse heart. Furthermore, GJA1-20k localizes to the mitochondrial outer membrane and induces a protective and DRP1 independent form of mitochondrial fission, preserving ATP production and generating less reactive oxygen species (ROS) under metabolic stress, providing powerful protection of myocardium to ischemic insult. In this manuscript, we focus on the detailed roles of GJA1-20k in mitochondria, and its interaction with the actin cytoskeleton.
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Laird DW, Lampe PD. Cellular mechanisms of connexin-based inherited diseases. Trends Cell Biol 2022; 32:58-69. [PMID: 34429228 PMCID: PMC8688313 DOI: 10.1016/j.tcb.2021.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 01/03/2023]
Abstract
The 21-member connexin gene family exhibits distinct tissue expression patterns that can cause a diverse array of over 30 inherited connexin-linked diseases ranging from deafness to skin defects and blindness. Intriguingly, germline mutations can cause disease in one tissue while other tissues that abundantly express the mutant connexin remain disease free, highlighting the importance of the cellular context of mutant expression. Modeling connexin pathologies in genetically modified mice and tissue-relevant cells has informed extensively on no less than a dozen gain- and loss-of-function mechanisms that underpin disease. This review focuses on how a deeper molecular understanding of the over 930 mutations in 11 connexin-encoding genes is foundational for creating a framework for therapeutic interventions.
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Affiliation(s)
- Dale W. Laird
- Departments of Anatomy and Cell Biology, and Physiology and Pharmacology, University of Western Ontario, London, ON, CANADA
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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10
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Duan J, Chen H, Li Y, Xu D, Li X, Zhang Z, Cheng J, Yang L, Li Q. 17β-Estradiol Enhances Porcine Meiosis Resumption from Autophagy-Induced Gap Junction Intercellular Communications and Connexin 43 Phosphorylation via the MEK/ERK Signaling Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11847-11855. [PMID: 34609142 DOI: 10.1021/acs.jafc.1c04212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Estrogen and its analogues are ubiquitous in agricultural environments, with large biological functions of oocyte development. Gap junction intercellular communications (GJICs) are the structural basis in cumulus-oocyte complexes (COCs) and regulate oocyte maturation and developmental material transport through a number of pathways. This study mainly determines the effect and potential mechanism of estrogen (17β-estradiol) in regulating GJICs in porcine COCs. In our study, 17β-estradiol increased porcine nuclear maturation in a time-dependent manner. The analysis revealed that 17β-estradiol upregulated the autophagy in COCs during in vitro maturation. In contrast with the control, 17β-estradiol decreased GJICs in a time-dependent manner between cumulus cells and oocytes, while it was consistent with the control group at 24 h. Carbenoxolone (CBX) blocks GJICs as a negative control group used in our system. Autophagy inhibitor autophinib decreased oocyte maturation, and the reduced nuclear maturation treated with autophinib was abolished by 17β-estradiol. Besides, the upregulation effect of autophinib on GJICs and transzonal projections (TZPs) was decreased by 17β-estradiol. 17β-Estradiol could reduce serine 368 phosphorylation of connexin 43 (Cx43) protein by autophinib in porcine COCs. These results were dependent upon the MEK/ERK signaling pathway. Furthermore, 17β-estradiol-induced GJICs and Cx43 phosphorylation were inhibited by autophinib or the MEK/ERK pathway inhibitors (Trametinib and FR 180204), indicating that 17β-estradiol regulated GJICs through the MEK/ERK signaling pathway. In conclusion, 17β-estradiol improves the autophagy-mediated nuclear maturation with downregulating GJICs and TZPs in porcine COCs. Such an effect occurs by phosphorylation of Cx43, which was regulated via the MEK/ERK signaling pathway.
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Affiliation(s)
- Jiaxin Duan
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Huali Chen
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621000, People's Republic of China
| | - Yuan Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Dejun Xu
- College of Animal Science and Technology, Southwest University, Chongqing, Sichuan 400000, People's Republic of China
| | - Xiaoya Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Zelin Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Jianyong Cheng
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Li Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
| | - Qingwang Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Xianyang, Shaanxi 712100, People's Republic of China
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11
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Connexin 43 and Connexin 26 Involvement in the Ponatinib-Induced Cardiomyopathy: Sex-Related Differences in a Murine Model. Int J Mol Sci 2021; 22:ijms22115815. [PMID: 34071707 PMCID: PMC8199144 DOI: 10.3390/ijms22115815] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/15/2022] Open
Abstract
Cardiac connexins (Cxs) are proteins responsible for proper heart function. They form gap junctions that mediate electrical and chemical signalling throughout the cardiac system, and thus enable a synchronized contraction. Connexins can also individually participate in many signal transduction pathways, interacting with intracellular proteins at various cellular compartments. Altered connexin expression and localization have been described in diseased myocardium and the aim of this study is to assess the involvement of Cx43, Cx26, and some related molecules in ponatinib-induced cardiac toxicity. Ponatinib is a new multi-tyrosine kinase inhibitor that has been successfully used against human malignancies, but its cardiotoxicity remains worrisome. Therefore, understanding its signaling mechanism is important to adopt potential anti cardiac damage strategies. Our experiments were performed on hearts from male and female mice treated with ponatinib and with ponatinib plus siRNA-Notch1 by using immunofluorescence, Western blotting, and proteomic analyses. The altered cardiac function and the change in Cxs expression observed in mice after ponatinib treatment, were results dependent on the Notch1 pathway and sex. Females showed a lower susceptibility to ponatinib than males. The downmodulation of cardiac Cx43, Cx26 and miR-122, high pS368-Cx43 phosphorylation, cell viability and survival activation could represent some of the female adaptative/compensatory reactions to ponatinib cardiotoxicity.
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12
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Zhang M, Cheng K, Chen H, Tu J, Shen Y, Pang L, Wu W, Yu Z. LncRNA AK020546 protects against cardiac ischemia-reperfusion injury by sponging miR-350-3p. Aging (Albany NY) 2021; 13:14219-14233. [PMID: 33988127 PMCID: PMC8202874 DOI: 10.18632/aging.203038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 02/25/2021] [Indexed: 11/25/2022]
Abstract
Long non-coding RNAs (lncRNAs) have been implicated in the development of cardiovascular diseases. We observed that lncRNA AK020546 was downregulated following ischemia/reperfusion injury to the myocardium and following H2O2 treatment in H9c2 cardiomyocytes. In vivo and in vitro studies showed that AK020546 overexpression attenuated the size of the ischemic area, reduced apoptosis among H9c2 cardiomyocytes, and suppressed the release of reactive oxygen species, lactic acid dehydrogenase, and malondialdehyde. AK020546 served as a competing endogenous RNA for miR-350-3p and activated the miR-350-3p target gene ErbB3. MiR-350-3p overexpression reversed the effects of AK020546 on oxidative stress injury and apoptosis in H9c2 cardiomyocytes. Moreover, ErbB3 knockdown alleviated the effects of AK020546 on the expression of ErbB3, Bcl-2, phosphorylated AKT, cleaved Caspase 3, and phosphorylated Bad. These findings suggest lncRNA AK020546 protects against ischemia/reperfusion and oxidative stress injury by sequestering miR-350-3p and activating ErbB3, which highlights its potential as a therapeutic target for ischemic heart diseases.
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Affiliation(s)
- Meiqi Zhang
- Department of Intensive Care Unit, Hangzhou Hospital of Traditional Chinese Medicine (Dingqiao), Guangxing Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Kang Cheng
- Department of Intensive Care Unit, Hangzhou Hospital of Traditional Chinese Medicine (Dingqiao), Guangxing Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Huan Chen
- Department of Emergency Medicine, Zhejiang Provincial Peoples Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Jianfeng Tu
- Department of Emergency Medicine, Zhejiang Provincial Peoples Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Ye Shen
- Department of Emergency Medicine, Zhejiang Provincial Peoples Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Lingxiao Pang
- Department of Emergency Medicine, Zhejiang Provincial Peoples Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Weihua Wu
- Department of Intensive Care Unit, Hangzhou Hospital of Traditional Chinese Medicine (Dingqiao), Guangxing Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Zhenfei Yu
- Department of Intensive Care Unit, Hangzhou Hospital of Traditional Chinese Medicine (Dingqiao), Guangxing Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
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13
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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: 23] [Impact Index Per Article: 7.7] [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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14
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Cx43 phosphorylation sites regulate pancreatic cancer metastasis. Oncogene 2021; 40:1909-1920. [PMID: 33603164 PMCID: PMC8191514 DOI: 10.1038/s41388-021-01668-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 01/03/2021] [Accepted: 01/18/2021] [Indexed: 01/30/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDA) is aggressive, highly metastatic and characterized by a robust desmoplasia. Connexin proteins that form gap junctions have been implicated in tumor suppression for over 30 years. Cx43, the most widely expressed connexin, regulates cell behaviors, including migration and proliferation. Thus, we hypothesized that Cx43 could regulate PDA progression. Phosphorylation of Cx43 by Casein Kinase 1 (CK1) regulates gap junction assembly. We interbred the well-established KrasLSL-G12D/+;p48Cre/+ (KC) mouse model of PDA with homozygous "knock-in" mutant Cx43 mice bearing amino acid substitution at CK1 sites (Cx43CK1A) and found profound and surprising effects on cancer progression. Crossing the Cx43CK1A mouse onto the KC background (termed KC;CxCK1A) led to significant extension of lifespan, from a median of 370 to 486 days (p = 0.03) and a decreased incidence of metastasis (p = 0.045). However, when we examined early stages of disease, we found more rapid onset of tissue remodeling in the KC;CxCK1A mouse followed by divergence to a cystic phenotype. During tumorigenesis, gap junctions are increasingly present in stromal cells of the KC mice but are absent from the KC;Cx43CK1A mice. Tail vein metastasis assays with cells derived from KC or KC;CxCK1A tumors showed that KC;CxCK1A cells could efficiently colonize the lung and downregulate Cx43 expression, arguing that inhibition of metastasis was not occurring at the distal site. Instead, stromal gap junctions, their associated signaling events or other unknown Cx43-dependent events facilitate metastatic capacity in the primary tumor.
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15
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Zhao Q, Liu F, Zhao Q, Zhang J, Luo J, Li X, Yang Y. Constitutive activation of ERK1/2 signaling protects against myocardial ischemia via inhibition of mitochondrial fragmentation in the aging heart. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:479. [PMID: 33850876 PMCID: PMC8039677 DOI: 10.21037/atm-21-503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background Studies have shown that the ability of the myocardium to tolerate ischemia becomes significantly compromised with age. During ischemia, several endogenous protective signals are activated to protect the heart from injury, among which extracellular-signal regulated kinase (ERK) 1/2 signaling has been established as playing a pivotal role. However, in aging hearts, the activation of ERK1/2 is compromised. Mitogen-activated protein kinase/ERK kinase (MEK) is a major regulator of ERK1/2 signaling. In the present study, we investigated whether transduction of CaMEK, a constitutively activated MEK, using adeno-associated virus serotype 9 (AAV9) could protect the aging heart against ischemia. Methods Myocardial ischemia models were established in aging mice and senescent cardiomyocytes, and AAV9-mediated delivery of CaMEK was applied. Echocardiography, fluorescent staining, transmission electron microscopy, flow cytometry, and immunoblotting were used to explore the effects of CaMEK and their underlying mechanism. Results AAV9-CaMEK activated ERK1/2 signaling and exerted cardioprotective effects against ischemia in aging hearts. Specifically, CaMEK transduction decreased dynamin-related protein-1 (Drp1) expression and phosphorylation at serine 616, resulting in improved mitochondrial morphology and function in aging ischemic hearts. Furthermore, CaMEK transduction exerted similar protective effects in senescent cardiomyocytes under hypoxia. Meanwhile, with the inhibition of ERK1/2 signaling in senescent cardiomyocytes under hypoxia, the opposite effects were observed, including an increase in mitochondrial fragmentation and aggravation of mitochondrial dysfunction and cell apoptosis. Conclusions Our results suggested that AAV9-CaMEK alleviated ischemia-induced myocardium injury in the aging heart, at least in part, through inhibition of mitochondrial fragmentation. Therefore, AAV9-CaMEK is a potential intervention for prevention of ischemia-induced injury of the aging myocardium.
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Affiliation(s)
- Qiang Zhao
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Fen Liu
- Xinjiang Key Laboratory of Cardiovascular Disease Research, Clinical Medicine Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Qian Zhao
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Jinyu Zhang
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Junyi Luo
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Xiaomei Li
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Yining Yang
- Department of Cardiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China.,Department of Cardiology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
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16
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He Y, Fu Y, Xi M, Zheng H, Zhang Y, Liu Y, Zhao Y, Xi J, He Y. Zn 2+ and mPTP mediate resveratrol-induced myocardial protection from endoplasmic reticulum stress. Metallomics 2021; 12:290-300. [PMID: 31872196 DOI: 10.1039/c9mt00264b] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Resveratrol displays cardioprotective activity; however, its mechanism of action remains unclear. In the current study, resveratrol-induced myocardial protection from endoplasmic reticulum stress (ERS) was investigated, focusing on the roles of Zn2+ and the mitochondrial permeability transition pore (mPTP). We found, using the MTT/LDH kit, that 2-DG-induced ERS significantly decreased H9c2 cell viability. Resveratrol markedly inhibited the expression of endoplasmic reticulum chaperone GRP 78/94 and ERS-related apoptosis proteins CHOP, Caspase12, and JNK induced by 2-DG. The zinc ion chelator TPEN, and ERK/GSK-3β inhibitors PD98059 and SB216763 and their siRNAs blocked resveratrol function. The AKT inhibitor LY294002 and siRNA did not alter the action of resveratrol. In addition, resveratrol significantly increased the phosphorylation of ERK and GSK-3β. Resveratrol prevented 2-DG-induced mPTP opening and increased intracellular Zn2+ concentration indicated by TMRE and Newport Green DCF fluorescence intensity, which were further abrogated by ERK/GSK-3β inhibitors and siRNAs. Our data suggested that resveratrol protected cardiac cells from ERS by mobilizing intracellular Zn2+ and preventing mPTP opening through the ERK/GSK-3β but not PI3K/AKT signaling pathway.
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Affiliation(s)
- Yifei He
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Yu Fu
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Mengyao Xi
- School of Nursing, Dalian Medical University, Dalian, 116044, China
| | - Huan Zheng
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Yidong Zhang
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Yulin Liu
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Yang Zhao
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Jinkun Xi
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
| | - Yonggui He
- Affiliated Hospital & Clinic School of Medicine, North China University of Science and Technology, Tangshan 063000, China.
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17
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Solan JL, Lampe PD. Src Regulation of Cx43 Phosphorylation and Gap Junction Turnover. Biomolecules 2020; 10:biom10121596. [PMID: 33255329 PMCID: PMC7759836 DOI: 10.3390/biom10121596] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/19/2020] [Accepted: 11/22/2020] [Indexed: 12/18/2022] Open
Abstract
The gap junction protein Connexin43 (Cx43) is highly regulated by phosphorylation at over a dozen sites by probably at least as many kinases. This Cx43 “kinome” plays an important role in gap junction assembly and turnover. We sought to gain a better understanding of the interrelationship of these phosphorylation events particularly related to src activation and Cx43 turnover. Using state-of-the-art live imaging methods, specific inhibitors and many phosphorylation-status specific antibodies, we found phospho-specific domains in gap junction plaques and show evidence that multiple pathways of disassembly exist and can be regulated at the cellular and subcellular level. We found Src activation promotes formation of connexisomes (internalized gap junctions) in a process involving ERK-mediated phosphorylation of S279/282. Proteasome inhibition dramatically and rapidly restored gap junctions in the presence of Src and led to dramatic changes in the Cx43 phospho-profile including to increased Y247, Y265, S279/282, S365, and S373 phosphorylation. Lysosomal inhibition, on the other hand, nearly eliminated phosphorylation on Y247 and Y265 and reduced S368 and S373 while increasing S279/282 phosphorylation levels. We present a model of gap junction disassembly where multiple modes of disassembly are regulated by phosphorylation and can have differential effects on cellular signaling.
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Affiliation(s)
- Joell L. Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Department of Global Health, Pathobiology Program, University of Washington, Seattle, WA 98109, USA
- Correspondence:
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18
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Xu D, He H, Liu D, Geng G, Li Q. A novel role of SIRT2 in regulating gap junction communications via connexin-43 in bovine cumulus-oocyte complexes. J Cell Physiol 2020; 235:7332-7343. [PMID: 32039484 DOI: 10.1002/jcp.29634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 01/30/2020] [Indexed: 01/04/2023]
Abstract
SIRT2, the predominantly cytosolic sirtuin, plays important role in multiple biological processes, including metabolism, stress response, and aging. However, the function of SIRT2 in gap junction intercellular communications (GJICs) of cumulus-oocyte complexes (COCs) is not yet known. The purpose of the present study was to evaluate the effect and underlining mechanism of SIRT2 on GJICs in COCs. Here, we found that treatment with SIRT2 inhibitors (SirReal2 or TM) inhibited bovine oocyte nuclear maturation. Further analysis revealed that SIRT2 inactivation disturbed the GJICs of COCs during in vitro maturation. Correspondingly, both the Cx43 phosphorylation levels and MEK/MER signaling pathways were induced by SIRT2 inhibition. Importantly, SIRT2-mediated Cx43 phosphorylation was completely abolished by treatment with MEK1/2 inhibitor (Trametinib). Furthermore, treatment with SIRT2 inhibitors resulted in the high levels of MEK1/2 acetylation. Functionally, downregulating the MER/ERK pathways with inhibitors (Trametinib or SCH772984) could attenuate the closure of GJICs caused by SIRT2 inactivation in partly. In addition, inhibition of SIRT2 activity significantly decreased the membrane and zona pellucida localization of Cx43 by upregulating the levels of Cx43 acetylation. Taken together, these results demonstrated a novel role that SIRT2 regulates GJICs via modulating the phosphorylation and deacetylation of Cx43 in COCs.
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Affiliation(s)
- Dejun Xu
- Department of Zoology and Animal Reproduction, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Huanshan He
- Department of Zoology and Animal Reproduction, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Dingbang Liu
- Department of Zoology and Animal Reproduction, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Guoxia Geng
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Qingwang Li
- Department of Zoology and Animal Reproduction, College of Animal Science and Technology, Northwest A&F University, Yangling, China
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Lastwika KJ, Dunn CA, Solan JL, Lampe PD. Phosphorylation of connexin 43 at MAPK, PKC or CK1 sites each distinctly alter the kinetics of epidermal wound repair. J Cell Sci 2019; 132:jcs.234633. [PMID: 31427427 DOI: 10.1242/jcs.234633] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/12/2019] [Indexed: 12/19/2022] Open
Abstract
The gap junction protein connexin 43 (Cx43) is a key player in wound healing, and inhibitors of Cx43, which speed epidermal wound healing, are currently in clinical trials. Here, we provide direct in vivo evidence that specific phosphorylation events on Cx43 change the physiological response during wound healing. Blocking phosphorylation, through mutation of serine residues in Cx43 at the protein kinase C (PKC) or casein kinase 1 (CK1) sites, significantly slowed the rate of wound closure in vivo and in vitro and resulted in a thicker epidermal layer after reepithelialization. Conversely, preventing Cx43 phosphorylation by mitogen-activated protein kinases (MAPKs) through mutation significantly increased the rate of wound closure in vivo Defects in migration, but not proliferation, in all mutants were partially rescued in vitro by changing serine residues to aspartic or glutamic acid. These data prove that specific Cx43 phosphorylation events play an important role at different stages of wound healing. Thus, a clear physiological understanding of the spatiotemporal regulation of kinase activation and consequent effects on gap junctions could lead to a more targeted approach to modulating Cx43 expression during wound healing.
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Affiliation(s)
- Kristin J Lastwika
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center Seattle, WA 98109, USA
| | - Clarence A Dunn
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center Seattle, WA 98109, USA
| | - Joell L Solan
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center Seattle, WA 98109, USA
| | - Paul D Lampe
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center Seattle, WA 98109, USA
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