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Barreto BC, Neves MVGD, Cardoso CMA, Meira CS, Daltro PS, Figueira CP, Santos GC, Silva DN, Távora F, Neto JDDS, Macambira SG, Lampe PD, Coutinho KCDS, Kasai Brunswick TH, Ribeiro dos Santos R, Campos de Carvalho AC, Soares MBP. The effects of inflammation on connexin 43 in chronic Chagas disease cardiomyopathy. Front Immunol 2024; 15:1440662. [PMID: 39136016 PMCID: PMC11317259 DOI: 10.3389/fimmu.2024.1440662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/11/2024] [Indexed: 08/15/2024] Open
Abstract
Background Cardiac arrhythmias are the main cause of sudden death due to Chronic Chagasic Cardiomyopathy (CCC). Here we investigated alterations in connexin 43 (Cx43) expression and phosphorylation in cardiomyocytes as well as associations with cardiac arrhythmias in CCC. Methods C57Bl/6 mice infected with Trypanosoma cruzi underwent cardiac evaluations at 6 and 12 months after infection via treadmill testing and EKG. Histopathology, cytokine gene expression, and distribution of total Cx43 and its phosphorylated forms Cx43S368 and Cx43S325/328/330 were investigated. Human heart samples obtained from subjects with CCC were submitted to immunofluorescence analysis. In vitro simulation of a pro-inflammatory microenvironment (IL-1β, TNF, and IFN-γ) was performed in H9c2 cells and iPSC-derived cardiomyocytes to evaluate Cx43 distribution, action potential duration, and Lucifer Yellow dye transfer. Results Mice chronically infected with T. cruzi exhibited impaired cardiac function associated with increased inflammation, fibrosis and upregulated IL-1β, TNF, and IFN-γ gene expression. Confocal microscopy revealed altered total Cx43, Cx43S368 and Cx43S325/328/330 localization and phosphorylation patterns in CCC, with dispersed staining outside the intercalated disc areas, i.e., in lateral membranes and the cytoplasm. Reduced co-localization of total Cx43 and N-cadherin was observed in the intercalated discs of CCC mouse hearts compared to controls. Similar results were obtained in human CCC heart samples, which showed Cx43 distribution outside the intercalated discs. Stimulation of human iPSC-derived cardiomyocytes or H9c2 cells with IL-1β, TNF, and IFN-γ induced alterations in Cx43 localization, reduced action potential duration and dye transfer between adjacent cells. Conclusion Heart inflammation in CCC affects the distribution and phosphorylation pattern of Cx43, which may contribute to the generation of conduction disturbances in Chagas disease.
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Affiliation(s)
- Breno Cardim Barreto
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- Department of Biochemistry and Biophysics, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil
- SENAI Institute of Innovation in Health Advanced Systems (CIMATEC ISI SAS), University Center SENAI/CIMATEC, Salvador, Bahia, Brazil
| | - Maria Vitória Gomes das Neves
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- Department of Biochemistry and Biophysics, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil
| | | | - Cássio Santana Meira
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- SENAI Institute of Innovation in Health Advanced Systems (CIMATEC ISI SAS), University Center SENAI/CIMATEC, Salvador, Bahia, Brazil
| | - Pâmela Santana Daltro
- Department of Biochemistry and Biophysics, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil
| | | | - Girlaine Café Santos
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- Department of Biochemistry and Biophysics, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil
| | - Daniela Nascimento Silva
- SENAI Institute of Innovation in Health Advanced Systems (CIMATEC ISI SAS), University Center SENAI/CIMATEC, Salvador, Bahia, Brazil
| | - Fábio Távora
- Messejana Heart and Lung Hospital, Fortaleza, Brazil
| | | | - Simone Garcia Macambira
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- Department of Biochemistry and Biophysics, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | | | | | - Ricardo Ribeiro dos Santos
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- SENAI Institute of Innovation in Health Advanced Systems (CIMATEC ISI SAS), University Center SENAI/CIMATEC, Salvador, Bahia, Brazil
| | | | - Milena Botelho Pereira Soares
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation (IGM-FIOCRUZ/BA), Salvador, Brazil
- SENAI Institute of Innovation in Health Advanced Systems (CIMATEC ISI SAS), University Center SENAI/CIMATEC, Salvador, Bahia, Brazil
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Lee KK, Celt N, Ardoña HAM. Looking both ways: Electroactive biomaterials with bidirectional implications for dynamic cell-material crosstalk. BIOPHYSICS REVIEWS 2024; 5:021303. [PMID: 38736681 PMCID: PMC11087870 DOI: 10.1063/5.0181222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 04/15/2024] [Indexed: 05/14/2024]
Abstract
Cells exist in natural, dynamic microenvironmental niches that facilitate biological responses to external physicochemical cues such as mechanical and electrical stimuli. For excitable cells, exogenous electrical cues are of interest due to their ability to stimulate or regulate cellular behavior via cascade signaling involving ion channels, gap junctions, and integrin receptors across the membrane. In recent years, conductive biomaterials have been demonstrated to influence or record these electrosensitive biological processes whereby the primary design criterion is to achieve seamless cell-material integration. As such, currently available bioelectronic materials are predominantly engineered toward achieving high-performing devices while maintaining the ability to recapitulate the local excitable cell/tissue microenvironment. However, such reports rarely address the dynamic signal coupling or exchange that occurs at the biotic-abiotic interface, as well as the distinction between the ionic transport involved in natural biological process and the electronic (or mixed ionic/electronic) conduction commonly responsible for bioelectronic systems. In this review, we highlight current literature reports that offer platforms capable of bidirectional signal exchange at the biotic-abiotic interface with excitable cell types, along with the design criteria for such biomaterials. Furthermore, insights on current materials not yet explored for biointerfacing or bioelectronics that have potential for bidirectional applications are also provided. Finally, we offer perspectives aimed at bringing attention to the coupling of the signals delivered by synthetic material to natural biological conduction mechanisms, areas of improvement regarding characterizing biotic-abiotic crosstalk, as well as the dynamic nature of this exchange, to be taken into consideration for material/device design consideration for next-generation bioelectronic systems.
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Affiliation(s)
- Kathryn Kwangja Lee
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, USA
| | - Natalie Celt
- Department of Biomedical Engineering, University of California, Irvine, California 92697, USA
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3
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Delligatti CE, Kirk JA. Glycation in the cardiomyocyte. VITAMINS AND HORMONES 2024; 125:47-88. [PMID: 38997172 DOI: 10.1016/bs.vh.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Glycation is a protein post-translational modification that can occur on lysine and arginine residues as a result of a non-enzymatic process known as the Maillard reaction. This modification is irreversible, so the only way it can be removed is by protein degradation and replacement. Small reactive carbonyl species, glyoxal and methylglyoxal, are the primary glycating agents and are elevated in several conditions associated with an increased risk of cardiovascular disease, including diabetes, rheumatoid arthritis, smoking, and aging. Thus, how protein glycation impacts the cardiomyocyte is of particular interest, to both understand how these conditions increase the risk of cardiovascular disease and how glycation might be targeted therapeutically. Glycation can affect the cardiomyocyte through extracellular mechanisms, including RAGE-based signaling, glycation of the extracellular matrix that modifies the mechanical environment, and signaling from the vasculature. Intracellular glycation of the cardiomyocyte can impact calcium handling, protein quality control and cell death pathways, as well as the cytoskeleton, resulting in a blunted contractility. While reducing protein glycation and its impact on the heart has been an active area of drug development, multiple clinical trials have had mixed results and these compounds have not been translated to the clinic-highlighting the challenges of modulating myocyte glycation. Here we will review protein glycation and its effects on the cardiomyocyte, therapeutic attempts to reverse these, and offer insight as to the future of glycation studies and patient treatment.
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Affiliation(s)
- Christine E Delligatti
- Department of Cell and Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Maywood, IL, United States
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Maywood, IL, United States.
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4
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Allbritton-King JD, García-Cardeña G. Endothelial cell dysfunction in cardiac disease: driver or consequence? Front Cell Dev Biol 2023; 11:1278166. [PMID: 37965580 PMCID: PMC10642230 DOI: 10.3389/fcell.2023.1278166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/09/2023] [Indexed: 11/16/2023] Open
Abstract
The vascular endothelium is a multifunctional cellular system which directly influences blood components and cells within the vessel wall in a given tissue. Importantly, this cellular interface undergoes critical phenotypic changes in response to various biochemical and hemodynamic stimuli, driving several developmental and pathophysiological processes. Multiple studies have indicated a central role of the endothelium in the initiation, progression, and clinical outcomes of cardiac disease. In this review we synthesize the current understanding of endothelial function and dysfunction as mediators of the cardiomyocyte phenotype in the setting of distinct cardiac pathologies; outline existing in vivo and in vitro models where key features of endothelial cell dysfunction can be recapitulated; and discuss future directions for development of endothelium-targeted therapeutics for cardiac diseases with limited existing treatment options.
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Affiliation(s)
- Jules D. Allbritton-King
- Department of Pathology, Center for Excellence in Vascular Biology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA, United States
| | - Guillermo García-Cardeña
- Department of Pathology, Center for Excellence in Vascular Biology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA, United States
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5
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Kariki O, Georgopoulos M, Katsillis N, Chatziantoniou A, Koskina S, Zygouri A, Saplaouras A, Bazoukis G, Gkouziouta A, Vlachos K, Dragasis S, Mililis P, Adamopoulos S, Efremidis M, Letsas KP. Contemporary management of ventricular arrhythmias in heart failure. AMERICAN JOURNAL OF CARDIOVASCULAR DISEASE 2023; 13:207-221. [PMID: 37736352 PMCID: PMC10509449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 07/04/2023] [Indexed: 09/23/2023]
Abstract
Enhanced ventricular arrhythmogenesis is commonly experienced by patients in the end-stage of heart failure spectrum. A high burden of ventricular arrhythmias can affect the ventricular systolic function, lead to unexpected hospitalizations and further deteriorate the prognosis. Management of ventricular arrhythmias in this population is challenging. Implantable cardioverter-defibrillators are protective for the immediate termination of life-threatening arrhythmias but they have no impact in reducing the arrhythmic burden. Combination treatment with invasive (catheter ablation, mechanical hemodynamic support, sympathetic denervation) and noninvasive (antiarrhythmic drugs, medical therapy for heart failure, programming of implantable devices) therapies is commonly required. The aim of this review is to present the available therapeutic options, with main focus on recently published data for catheter ablation and provide a stepwise treatment approach.
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Affiliation(s)
- Ourania Kariki
- Department of Cardiology, Onassis Cardiac Surgery CenterAthens, Greece
| | | | - Nikitas Katsillis
- Department of Cardiology, Onassis Cardiac Surgery CenterAthens, Greece
| | | | - Stavroula Koskina
- Department of Cardiology, Onassis Cardiac Surgery CenterAthens, Greece
| | - Andromahi Zygouri
- Department of Cardiology, Onassis Cardiac Surgery CenterAthens, Greece
| | | | - George Bazoukis
- Department of Cardiology, Larnaca General HospitalLarnaca, Cyprus
| | | | | | | | | | | | - Michael Efremidis
- Department of Cardiology, Onassis Cardiac Surgery CenterAthens, Greece
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6
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Abstract
Gap junctions, comprising connexin proteins, create conduits directly coupling the cytoplasms of adjacent cells. Expressed in essentially all tissues, dynamic gap junction structures enable the exchange of small molecules including ions and second messengers, and are central to maintenance of homeostasis and synchronized excitability. With such diverse and critical roles throughout the body, it is unsurprising that alterations to gap junction and/or connexin expression and function underlie a broad array of age-related pathologies. From neurological dysfunction to cardiac arrhythmia and bone loss, it is hard to identify a human disease state that does not involve reduced, or in some cases inappropriate, intercellular communication to affect organ function. With a complex life cycle encompassing several key regulatory steps, pathological gap junction remodeling during ageing can arise from alterations in gene expression, translation, intracellular trafficking, and posttranslational modification of connexins. Connexin proteins are now known to "moonlight" and perform a variety of non-junctional functions in the cell, independent of gap junctions. Furthermore, connexin "hemichannels" on the cell surface can communicate with the extracellular space without ever coupling to an adjacent cell to form a gap junction channel. This chapter will focus primarily on gap junctions in ageing, but such non-junctional connexin functions will be referred to where appropriate and the full spectrum of connexin biology should be noted as potentially causative/contributing to some findings in connexin knockout animals, for example.
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Affiliation(s)
- Michael J Zeitz
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA.,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA
| | - James W Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA. .,FBRI Center for Vascular and Heart Research, Roanoke, VA, USA. .,Department of Biological Sciences, College of Science, Virginia Tech, Blacksburg, VA, USA. .,Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA.
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7
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Guo F, Hall AR, Tape CJ, Ling S, Pointon A. Intra- and intercellular signaling pathways associated with drug-induced cardiac pathophysiology. Trends Pharmacol Sci 2021; 42:675-687. [PMID: 34092416 DOI: 10.1016/j.tips.2021.05.004] [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: 12/10/2020] [Revised: 04/20/2021] [Accepted: 05/06/2021] [Indexed: 11/30/2022]
Abstract
Cardiac physiology and homeostasis are maintained by the interaction of multiple cell types, via both intra- and intercellular signaling pathways. Perturbations in these signaling pathways induced by oncology therapies can reduce cardiac function, ultimately leading to heart failure. As cancer survival increases, related cardiovascular complications are becoming increasingly prevalent, thus identifying the perturbations and cell signaling drivers of cardiotoxicity is increasingly important. Here, we discuss the homotypic and heterotypic cellular interactions that form the basis of intra- and intercellular cardiac signaling pathways, and how oncological agents disrupt these pathways, leading to heart failure. We also highlight the emerging systems biology techniques that can be applied, enabling a deeper understanding of the intra- and intercellular signaling pathways across multiple cell types associated with cardiovascular toxicity.
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Affiliation(s)
- Fei Guo
- Functional and Mechanistic Safety, Clinical Pharmacology and Safety Sciences, Research and Development, AstraZeneca, Cambridge, UK; Cell Communication Laboratory, Department of Oncology, University College London Cancer Institute, London, WC1E 6DD, UK
| | - Andrew R Hall
- Functional and Mechanistic Safety, Clinical Pharmacology and Safety Sciences, Research and Development, AstraZeneca, Cambridge, UK
| | - Christopher J Tape
- Cell Communication Laboratory, Department of Oncology, University College London Cancer Institute, London, WC1E 6DD, UK
| | - Stephanie Ling
- Imaging and Data Analytics, Clinical Pharmacology and Safety Sciences, Research and Development, AstraZeneca, Cambridge, UK
| | - Amy Pointon
- Functional and Mechanistic Safety, Clinical Pharmacology and Safety Sciences, Research and Development, AstraZeneca, Cambridge, UK.
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8
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Wu X, Zhang W, Li Y, Lin X. Structure and Function of Cochlear Gap Junctions and Implications for the Translation of Cochlear Gene Therapies. Front Cell Neurosci 2019; 13:529. [PMID: 31827424 PMCID: PMC6892400 DOI: 10.3389/fncel.2019.00529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/13/2019] [Indexed: 12/23/2022] Open
Abstract
Connexins (Cxs) are ubiquitous membrane proteins that are found throughout vertebrate organs, acting as building blocks of the gap junctions (GJs) known to play vital roles in the normal function of many organs. Mutations in Cx genes (particularly GJB2, which encodes Cx26) cause approximately half of all cases of congenital hearing loss in newborns. Great progress has been made in understanding GJ function and the molecular mechanisms for the role of Cxs in the cochlea. Data reveal that multiple types of Cxs work together to ensure normal development and function of the cochlea. These findings include many aspects not proposed in the classic K+ recycling theory, such as the formation of normal cochlear morphology (e.g., the opening of the tunnel of Corti), the fine-tuning of the innervation of nerve fibers to the hair cells (HCs), the maturation of the ribbon synapses, and the initiation of the endocochlear potential (EP). New data, especially those collected from targeted modification of major Cx genes in the mouse cochlea, have demonstrated that Cx26 plays an essential role in the postnatal maturation of the cochlea. Studies also show that Cx26 and Cx30 assume very different roles in the EP generation, given that only Cx26 is required for normal hearing. This article will review our current understanding of the molecular structure, cellular distribution, and major functions of cochlear GJs. Potential implications of the knowledge of cochlear GJs on the design and implementation of translational studies of cochlear gene therapies for Cx mutations are also discussed.
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Affiliation(s)
- Xuewen Wu
- Department of Otolaryngology, Head-Neck and Surgery, Xiangya Hospital of Central South University, Changsha, China
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
| | - Wenjuan Zhang
- Department of Otolaryngology, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yihui Li
- Department of Pharmacy, Changsha Hospital of Traditional Medicine, Changsha, China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
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9
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Basheer WA, Shaw RM. Connexin 43 and CaV1.2 Ion Channel Trafficking in Healthy and Diseased Myocardium. Circ Arrhythm Electrophysiol 2018; 9:e001357. [PMID: 27266274 DOI: 10.1161/circep.115.001357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/29/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Wassim A Basheer
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.).
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10
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Progesterone Via its Type-A Receptor Promotes Myometrial Gap Junction Coupling. Sci Rep 2017; 7:13357. [PMID: 29042599 PMCID: PMC5645358 DOI: 10.1038/s41598-017-13488-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 09/20/2017] [Indexed: 12/17/2022] Open
Abstract
Effective labour contractions require synchronization of myometrial cells through gap junctions (GJs). Clasically, progesterone (P4) is known to inhibit the expression of connexin-43 (Cx43, major component of GJs) and GJ formation in myometrium. Our current study is based on a striking observation that challenges this dogma. We observed conspicuous differences in the intracellular localization of Cx43 protein in PRA versus PRB expressing myocytes. Thus in P4 stimulated PRA cells Cx43 protein forms GJs, whereas in PRB cells the forward trafficking of Cx43 and GJ formation is inhibited even when Cx43 is overexpressed. We found that P4, via PRA/B, differentially regulates Cx43 translation to generate a Cx43-20 K isoform, which facilitates the transport of full length Cx43 to plasma membrane. The P4 mediated regulation of Cx43 trafficking and GJ formation occurs via non-genomic pathway and involves the regulation of mTOR signaling since inhibition of this pathway restored the Cx43 trafficking defect in PRB cells. We propose that PRA is a master regulator of Cx43 expression, GJ formation and myocyte connectivity/synchronization for labour.
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11
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Epifantseva I, Shaw RM. Intracellular trafficking pathways of Cx43 gap junction channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:40-47. [PMID: 28576298 DOI: 10.1016/j.bbamem.2017.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/11/2022]
Abstract
Gap Junction (GJ) channels, including the most common Connexin 43 (Cx43), have fundamental roles in excitable tissues by facilitating rapid transmission of action potentials between adjacent cells. For instance, synchronization during each heartbeat is regulated by these ion channels at the cardiomyocyte cell-cell border. Cx43 protein has a short half-life, and rapid synthesis and timely delivery of those proteins to particular subdomains are crucial for the cellular organization of gap junctions and maintenance of intracellular coupling. Impairment in gap junction trafficking contributes to dangerous complications in diseased hearts such as the arrhythmias of sudden cardiac death. Of recent interest are the protein-protein interactions with the Cx43 carboxy-terminus. These interactions have significant impact on the full length Cx43 lifecycle and also contribute to trafficking of Cx43 as well as possibly other functions. We are learning that many of the known non-canonical roles of Cx43 can be attributed to the recently identified six endogenous Cx43 truncated isoforms which are produced by internal translation. In general, alternative translation is a new leading edge for proteome expansion and therapeutic drug development. This review highlights recent mechanisms identified in the trafficking of gap junction channels, involvement of other proteins contributing to the delivery of channels to the cell-cell border, and understanding of possible roles of the newly discovered alternatively translated isoforms in Cx43 biology. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Irina Epifantseva
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.; Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA..
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12
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Spatio-temporal regulation of connexin43 phosphorylation and gap junction dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:83-90. [PMID: 28414037 DOI: 10.1016/j.bbamem.2017.04.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/05/2017] [Accepted: 04/11/2017] [Indexed: 01/23/2023]
Abstract
Gap junctions are specialized membrane domains containing tens to thousands of intercellular channels. These channels permit exchange of small molecules (<1000Da) including ions, amino acids, nucleotides, metabolites and secondary messengers (e.g., calcium, glucose, cAMP, cGMP, IP3) between cells. The common reductionist view of these structures is that they are composed entirely of integral membrane proteins encoded by the 21 member connexin human gene family. However, it is clear that the normal physiological function of this structure requires interaction and regulation by a variety of proteins, especially kinases. Phosphorylation is capable of directly modulating connexin channel function but the most dramatic effects on gap junction activity occur via the organization of the gap junction structures themselves. This is a direct result of the short half-life of the primary gap junction protein, connexin, which requires them to be constantly assembled, remodeled and turned over. The biological consequences of this remodeling are well illustrated during cardiac ischemia, a process wherein gap junctions are disassembled and remodeled resulting in arrhythmia and ultimately heart failure. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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MicroRNA-19b Downregulates Gap Junction Protein Alpha1 and Synergizes with MicroRNA-1 in Viral Myocarditis. Int J Mol Sci 2016; 17:ijms17050741. [PMID: 27213338 PMCID: PMC4881563 DOI: 10.3390/ijms17050741] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 05/07/2016] [Accepted: 05/10/2016] [Indexed: 12/23/2022] Open
Abstract
Viral myocarditis (VMC) is a life-threatening disease that leads to heart failure or cardiac arrhythmia. A large number of researches have revealed that mircroRNAs (miRNAs) participate in the pathological processes of VMC. We previously reported that miR-1 repressed the expression of gap junction protein α1 (GJA1) in VMC. In this study, miR-19b was found to be significantly upregulated using the microarray analysis in a mouse model of VMC, and overexpression of miR-19b led to irregular beating pattern in human cardiomyocytes derived from the induced pluripotent stem cells (hiPSCs-CMs). The upregulation of miR-19b was associated with decreased GJA1 in vivo. Furthermore, a miR-19b inhibitor increased, while its mimics suppressed the expression of GJA1 in HL-1 cells. When GJA1 was overexpressed, the miR-19b mimics-mediated irregular beating was reversed in hiPSCs-CMs. In addition, the effect of miR-19b on GJA1 was enhanced by miR-1 in a dose-dependent manner. These data suggest miR-19b contributes to irregular beating through regulation of GJA1 by cooperating with miR-1. Based on the present and our previous studies, it could be indicated that miR-19b and miR-1 might be critically involved in cardiac arrhythmia associated with VMC.
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Chen CC, Kuo CY, Chen RF. Role of CAPE on cardiomyocyte protection via connexin 43 regulation under hypoxia. Int J Med Sci 2016; 13:754-758. [PMID: 27766024 PMCID: PMC5069410 DOI: 10.7150/ijms.15847] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/22/2016] [Indexed: 01/26/2023] Open
Abstract
Background: Cardiomyocyte under hypoxia cause cell death or damage is associated with heart failure. Gap junction, such as connexin 43 play a role in regulation of heart function under hypoxia. Caffeic acid phenethyl ester (CAPE) has been reported as an active component of propolis, has antioxidative, anti-inflammatory antiproliferative and antineoplastic biological properties. Aims: Connexin 43 appear to have a critical role in heart failure under hypoxia, there has been considerable interest in identifying the candidate component or compound to reduce cell death. Methods: In this study, we used human cardiomyocyte as a cell model to study the role of connexin 43 in hypoxia- incubated human cardiomyocyte in absence or presence of CAPE treatment. Results: Results showed that hypoxia induced connexin 43 expression, but not altered in connexin 40. Interestingly, CAPE attenuates hypoxia-caused connexin 43 down-regulation and cell death or cell growth inhibition. Conclusion: We suggested that reduction of cell death in cardiomyocytes by CAPE is associated with an increase in connexin 43 expression.
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Affiliation(s)
- Chien-Cheng Chen
- Department of Cardiology, Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Chan-Yen Kuo
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Chung-li, Taiwan, 32001, Republic of China
| | - Rong-Fu Chen
- Research Assistant Center, Show Chwan Health Care System, Changhua, Taiwan
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Basheer W, Shaw R. The "tail" of Connexin43: An unexpected journey from alternative translation to trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1848-56. [PMID: 26526689 DOI: 10.1016/j.bbamcr.2015.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
Abstract
With each heartbeat, Connexin43 (Cx43) cell-cell communication gap junctions are needed to rapidly spread and coordinate excitation signals for an effective heart contraction. The correct formation and delivery of channels to their respective membrane subdomain is referred to as protein trafficking. Altered Cx43 trafficking is a dangerous complication of diseased myocardium which contributes to the arrhythmias of sudden cardiac death. Cx43 has also been found to regulate many other cellular processes that cannot be explained by cell-cell communication. We recently identified the existence of up to six endogenous internally translated Cx43 N-terminal truncated isoforms from the same full-length mRNA molecule. This is the first evidence that alternative translation is possible for human ion channels and in human heart. Interestingly, we found that these internally translated isoforms, more specifically the 20 kDa isoform (GJA1-20k), is important for delivery of Cx43 to its respective membrane subdomain. This review covers recent advances in Cx43 trafficking and potential importance of alternatively translated Cx43 truncated isoforms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Wassim Basheer
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Robin Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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16
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Gago-Fuentes R, Fernández-Puente P, Megias D, Carpintero-Fernández P, Mateos J, Acea B, Fonseca E, Blanco FJ, Mayan MD. Proteomic Analysis of Connexin 43 Reveals Novel Interactors Related to Osteoarthritis. Mol Cell Proteomics 2015; 14:1831-45. [PMID: 25903580 DOI: 10.1074/mcp.m115.050211] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 11/06/2022] Open
Abstract
We have previously reported that articular chondrocytes in tissue contain long cytoplasmic arms that physically connect two distant cells. Cell-to-cell communication occurs through connexin channels termed Gap Junction (GJ) channels, which achieve direct cellular communication by allowing the intercellular exchange of ions, small RNAs, nutrients, and second messengers. The Cx43 protein is overexpressed in several human diseases and inflammation processes and in articular cartilage from patients with osteoarthritis (OA). An increase in the level of Cx43 is known to alter gene expression, cell signaling, growth, and cell proliferation. The interaction of proteins with the C-terminal tail of connexin 43 (Cx43) directly modulates GJ-dependent and -independent functions. Here, we describe the isolation of Cx43 complexes using mild extraction conditions and immunoaffinity purification. Cx43 complexes were extracted from human primary articular chondrocytes isolated from healthy donors and patients with OA. The proteomic content of the native complexes was determined using LC-MS/MS, and protein associations with Cx43 were validated using Western blot and immunolocalization experiments. We identified >100 Cx43-associated proteins including previously uncharacterized proteins related to nucleolar functions, RNA transport, and translation. We also identified several proteins involved in human diseases, cartilage structure, and OA as novel functional Cx43 interactors, which emphasized the importance of Cx43 in the normal physiology and structural and functional integrity of chondrocytes and articular cartilage. Gene Ontology (GO) terms of the proteins identified in the OA samples showed an enrichment of Cx43-interactors related to cell adhesion, calmodulin binding, the nucleolus, and the cytoskeleton in OA samples compared with healthy samples. However, the mitochondrial proteins SOD2 and ATP5J2 were identified only in samples from healthy donors. The identification of Cx43 interactors will provide clues to the functions of Cx43 in human cells and its roles in the development of several diseases, including OA.
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Affiliation(s)
- Raquel Gago-Fuentes
- From the ‡CellCOM Research Group. Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC, University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Patricia Fernández-Puente
- §Rheumatology Division, ProteoRed/ISCIII, Proteomics Group, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain; ¶Rheumatology Division, CIBER-BBN/ISCIII, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Diego Megias
- ‖Confocal Microscopy Core Unit. Centro Nacional de Investigaciones Oncológicas (CNIO), 28029, Madrid, Spain
| | - Paula Carpintero-Fernández
- From the ‡CellCOM Research Group. Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC, University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Jesus Mateos
- §Rheumatology Division, ProteoRed/ISCIII, Proteomics Group, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain; ¶Rheumatology Division, CIBER-BBN/ISCIII, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Benigno Acea
- From the ‡CellCOM Research Group. Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC, University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Eduardo Fonseca
- From the ‡CellCOM Research Group. Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC, University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Francisco Javier Blanco
- §Rheumatology Division, ProteoRed/ISCIII, Proteomics Group, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain; ¶Rheumatology Division, CIBER-BBN/ISCIII, Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC. University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain
| | - Maria Dolores Mayan
- From the ‡CellCOM Research Group. Instituto de Investigación Biomédica A Coruña (INIBIC), XXIAC, University of A Coruña. Xubias de Arriba 84, 15006 A Coruña, Spain;
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Xiao S, Shaw RM. Cardiomyocyte protein trafficking: Relevance to heart disease and opportunities for therapeutic intervention. Trends Cardiovasc Med 2014; 25:379-89. [PMID: 25649302 DOI: 10.1016/j.tcm.2014.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 11/30/2022]
Abstract
Cardiomyocytes, the individual contractile units of heart muscle, are long-lived and robust. Given the longevity of these cells, it can be easy to overlook their dynamic intracellular environment that contain rapid protein movements and frequent protein turnover. Critical gene transcription and protein translation occur continuously, as well as trafficking and localization of proteins to specific functional zones of cell membrane. As heart failure becomes an increasingly important clinical entity, growing numbers of investigative teams are examining the cell biology of healthy and diseased cardiomyocytes. In this review, we introduce the major architectural structures and types of protein movements within cardiac cells, and then review recent studies that explore the regulation of such movements. We conclude by introducing current translational directions of the basic studies with a focus on novel areas of therapeutic development.
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Affiliation(s)
- Shaohua Xiao
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA; Department of Medicine, University of California Los Angeles, Los Angeles, CA.
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18
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Zhang SS, Shaw RM. Trafficking highways to the intercalated disc: new insights unlocking the specificity of connexin 43 localization. ACTA ACUST UNITED AC 2014; 21:43-54. [PMID: 24460200 DOI: 10.3109/15419061.2013.876014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
With each heartbeat, billions of cardiomyocytes work in concert to propagate the electrical excitation needed to effectively circulate blood. Regulated expression and timely delivery of connexin proteins to form gap junctions at the specialized cell-cell contact region, known as the intercalated disc, is essential to ventricular cardiomyocyte coupling. We focus this review on several regulatory mechanisms that have been recently found to govern the lifecycle of connexin 43 (Cx43), the short-lived and most abundantly expressed connexin in cardiac ventricular muscle. The Cx43 lifecycle begins with gene expression, followed by oligomerization into hexameric channels, and then cytoskeletal-based transport toward the disc region. Once delivered, hemichannels interact with resident disc proteins and are organized to effect intercellular coupling. We highlight recent studies exploring regulation of Cx43 localization to the intercalated disc, with emphasis on alternatively translated Cx43 isoforms and cytoskeletal transport machinery that together regulate Cx43 gap junction coupling between cardiomyocytes.
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Bouvy C, Gheldof D, Chatelain C, Mullier F, Dogné JM. Contributing role of extracellular vesicles on vascular endothelium haemostatic balance in cancer. J Extracell Vesicles 2014; 3:24400. [PMID: 25045423 PMCID: PMC4095764 DOI: 10.3402/jev.v3.24400] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/13/2014] [Accepted: 06/13/2014] [Indexed: 12/21/2022] Open
Abstract
Extracellular vesicles (EVs) generated during tumourigenesis are thought to play a major role in the hypercoagulant state observed in cancer patients. They exhibit negatively charged phospholipids and tissue factor (TF) that promote coagulation cascade activation. In addition, they contain surface proteins and cytoplasmic molecules, both originating from the producing cell that can impact target cells’ expression. By targeting endothelial cells of blood vessels, these EVs could disturb the physiological anticoagulant properties of these cells and be partly responsible for the vascular endothelium activation observed in cancer patients. Indeed, vascular endothelium naturally exhibits heparin-like proteoglycan, TF pathway inhibitor and protein C anticoagulant pathway that prevent thrombosis in physiological condition. An overexpression of TF and a decreased expression of coagulation cascade inhibitors have been reported after EVs’ treatment of endothelial cells. The induction of apoptosis and an increased expression of platelet adhesion molecules have also been highlighted. These events may promote thrombus formation in cancer. The aim of this paper is to provide a targeted review on the current evidence and knowledge of roles and impact of EVs on endothelial surface anticoagulant and procoagulant factors and cellular adhesion molecules expression.
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Affiliation(s)
- Céline Bouvy
- Department of Pharmacy, Namur Research Institute of Life Sciences (NARILIS), Namur Thrombosis and Hemostasis Center (NTHC), University of Namur, Namur, Belgium
| | - Damien Gheldof
- Department of Hematology, Namur Thrombosis and Hemostasis Center (NTHC), CHU Dinant-Godinne, UCL Namur, Yvoir, Belgium
| | - Christian Chatelain
- Department of Hematology, Namur Thrombosis and Hemostasis Center (NTHC), CHU Dinant-Godinne, UCL Namur, Yvoir, Belgium
| | - François Mullier
- Department of Hematology, Namur Thrombosis and Hemostasis Center (NTHC), CHU Dinant-Godinne, UCL Namur, Yvoir, Belgium
| | - Jean-Michel Dogné
- Department of Pharmacy, Namur Research Institute of Life Sciences (NARILIS), Namur Thrombosis and Hemostasis Center (NTHC), University of Namur, Namur, Belgium
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20
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Smyth JW, Zhang SS, Sanchez JM, Lamouille S, Vogan JM, Hesketh GG, Hong T, Tomaselli GF, Shaw RM. A 14-3-3 mode-1 binding motif initiates gap junction internalization during acute cardiac ischemia. Traffic 2014; 15:684-99. [PMID: 24612377 PMCID: PMC4278178 DOI: 10.1111/tra.12169] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 02/03/2023]
Abstract
Altered phosphorylation and trafficking of connexin 43 (Cx43) during acute ischemia contributes to arrhythmogenic gap junction remodeling, yet the critical sequence and accessory proteins necessary for Cx43 internalization remain unresolved. 14-3-3 proteins can regulate protein trafficking, and a 14-3-3 mode-1 binding motif is activated upon phosphorylation of Ser373 of the Cx43 C-terminus. We hypothesized that Cx43(Ser373) phosphorylation is important to pathological gap junction remodeling. Immunofluorescence in human heart reveals the enrichment of 14-3-3 proteins at intercalated discs, suggesting interaction with gap junctions. Knockdown of 14-3-3τ in cell lines increases gap junction plaque size at cell-cell borders. Cx43(S373A) mutation prevents Cx43/14-3-3 complexing and stabilizes Cx43 at the cell surface, indicating avoidance of degradation. Using Langendorff-perfused mouse hearts, we detect phosphorylation of newly internalized Cx43 at Ser373 and Ser368 within 30 min of no-flow ischemia. Phosphorylation of Cx43 at Ser368 by protein kinase C and Ser255 by mitogen-activated protein kinase has previously been implicated in Cx43 internalization. The Cx43(S373A) mutant is resistant to phosphorylation at both these residues and does not undergo ubiquitination, revealing Ser373 phosphorylation as an upstream gatekeeper of a posttranslational modification cascade necessary for Cx43 internalization. Cx43(Ser373) phosphorylation is a potent target for therapeutic interventions to preserve gap junction coupling in the stressed myocardium.
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Affiliation(s)
- James W. Smyth
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center
| | - Shan-Shan Zhang
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center
| | - Jose M. Sanchez
- Department of Medicine, University of California San Francisco
| | - Samy Lamouille
- Department of Medicine, University of California San Francisco
| | - Jacob M. Vogan
- Department of Medicine, University of California San Francisco
| | | | - TingTing Hong
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center
- Department of Medicine, University of California Los Angeles
| | | | - Robin M. Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center
- Department of Medicine, University of California Los Angeles
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21
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Stamper IJ, Jackson E, Wang X. Phase transitions in pancreatic islet cellular networks and implications for type-1 diabetes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:012719. [PMID: 24580269 PMCID: PMC4172977 DOI: 10.1103/physreve.89.012719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Indexed: 06/03/2023]
Abstract
In many aspects the onset of a chronic disease resembles a phase transition in a complex dynamic system: Quantitative changes accumulate largely unnoticed until a critical threshold is reached, which causes abrupt qualitative changes of the system. In this study we examine a special case, the onset of type-1 diabetes (T1D), a disease that results from loss of the insulin-producing pancreatic islet β cells. Within each islet, the β cells are electrically coupled to each other via gap-junctional channels. This intercellular coupling enables the β cells to synchronize their insulin release, thereby generating the multiscale temporal rhythms in blood insulin that are critical to maintaining blood glucose homeostasis. Using percolation theory we show how normal islet function is intrinsically linked to network connectivity. In particular, the critical amount of β-cell death at which the islet cellular network loses site percolation is consistent with laboratory and clinical observations of the threshold loss of β cells that causes islet functional failure. In addition, numerical simulations confirm that the islet cellular network needs to be percolated for β cells to synchronize. Furthermore, the interplay between site percolation and bond strength predicts the existence of a transient phase of islet functional recovery after onset of T1D and introduction of treatment, potentially explaining the honeymoon phenomenon. Based on these results, we hypothesize that the onset of T1D may be the result of a phase transition of the islet β-cell network.
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Affiliation(s)
- I. J. Stamper
- Department of Physics, the University of Alabama at Birmingham, Birmingham, Alabama, USA
- The Comprehensive Diabetes Center, the University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Elais Jackson
- Department of Computer and Information Sciences, the University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Xujing Wang
- Department of Physics, the University of Alabama at Birmingham, Birmingham, Alabama, USA
- The Comprehensive Diabetes Center, the University of Alabama at Birmingham, Birmingham, Alabama, USA
- Systems Biology Center, the National Heart, Lung, and Blood Institute, the National Institutes of Health, Bethesda, Maryland, USA
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22
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The dynamics of connexin expression, degradation and localisation are regulated by gonadotropins during the early stages of in vitro maturation of swine oocytes. PLoS One 2013; 8:e68456. [PMID: 23861906 PMCID: PMC3701662 DOI: 10.1371/journal.pone.0068456] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/04/2013] [Indexed: 12/25/2022] Open
Abstract
Gap junctional communication (GJC) plays a primordial role in oocyte maturation and meiotic resumption in mammals by directing the transfer of numerous molecules between cumulus cells and the oocyte. Gap junctions are made of connexins (Cx), proteins that regulate GJC in numerous ways. Understanding the dynamic regulation of connexin arrangements during in vitro maturation (IVM) could provide a powerful tool for controlling meiotic resumption and consequently in vitro development of fully competent oocytes. However, physiological events happening during the early hours of IVM may still be elucidated. The present study reports the dynamic regulation of connexin expression, degradation and localization during this stage. Cx43, Cx45 and Cx60 were identified as the main connexins expressed in swine COC. Cx43 and Cx45 transcripts were judged too static to be a regulator of GJC, while Cx43 protein expression was highly responsive to gonadotropins, suggesting that it might be the principal regulator of GJC. In addition, the degradation of Cx43 expressed after 4.5 h of IVM in response to equine chorionic gonadotropin appeared to involve the proteasomal complex. Cx43 localisation appeared to be associated with GJC. Taken together, these results show for the first time that gonadotropins regulate Cx43 protein expression, degradation and localisation in porcine COC during the first several hours of IVM. Regulation of Cx43 may in turn, via GJC, participate in the development of fully competent oocytes.
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23
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Leone A, Lecci RM, Durante M, Piraino S. Extract from the zooxanthellate jellyfish Cotylorhiza tuberculata modulates gap junction intercellular communication in human cell cultures. Mar Drugs 2013; 11:1728-62. [PMID: 23697954 PMCID: PMC3707171 DOI: 10.3390/md11051728] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 04/24/2013] [Accepted: 04/25/2013] [Indexed: 12/13/2022] Open
Abstract
On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778) has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7) and human epidermal keratinocytes (HEKa). The composition of the jellyfish extract included photosynthetic pigments, valuable ω-3 and ω-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC) differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed.
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Affiliation(s)
- Antonella Leone
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-0832-422-615; Fax: +39-0832-422-620
| | - Raffaella Marina Lecci
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
| | - Miriana Durante
- Institute of Sciences of Food Production, National Research Council, Unit of Lecce (CNR, ISPA), Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mails: (R.M.L.); (M.D.)
| | - Stefano Piraino
- CoNISMa, National Interuniversity Consortium on Marine Sciences, Local Unit of Lecce, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy; E-Mail:
- University of Salento, Via Prov.le Lecce-Monteroni, Lecce 73100, Italy
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24
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Insights into the role of cell-cell junctions in physiology and disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:187-221. [PMID: 24016526 DOI: 10.1016/b978-0-12-407694-5.00005-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Contacting cells establish different classes of intricate structures at the cell-cell junctions. These structures are of increasing research interest as they regulate a broad variety of processes in development and disease. Further, in vitro studies are revealing that various cell-cell interaction proteins are involved not only in cell-cell processes but also in many additional aspects of physiology, such as migration and apoptosis. This chapter reviews the basic classification of cell-cell junctional structures and some of their representative proteins. Their roles in development and disease are briefly outlined, followed by a section on contemporary methods for probing cell-cell interactions and some recent developments. This chapter concludes with a few suggestions for potential research directions to further develop this promising area of study.
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25
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Balse E, Steele DF, Abriel H, Coulombe A, Fedida D, Hatem SN. Dynamic of Ion Channel Expression at the Plasma Membrane of Cardiomyocytes. Physiol Rev 2012; 92:1317-58. [DOI: 10.1152/physrev.00041.2011] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiac myocytes are characterized by distinct structural and functional entities involved in the generation and transmission of the action potential and the excitation-contraction coupling process. Key to their function is the specific organization of ion channels and transporters to and within distinct membrane domains, which supports the anisotropic propagation of the depolarization wave. This review addresses the current knowledge on the molecular actors regulating the distinct trafficking and targeting mechanisms of ion channels in the highly polarized cardiac myocyte. In addition to ubiquitous mechanisms shared by other excitable cells, cardiac myocytes show unique specialization, illustrated by the molecular organization of myocyte-myocyte contacts, e.g., the intercalated disc and the gap junction. Many factors contribute to the specialization of the cardiac sarcolemma and the functional expression of cardiac ion channels, including various anchoring proteins, motors, small GTPases, membrane lipids, and cholesterol. The discovery of genetic defects in some of these actors, leading to complex cardiac disorders, emphasizes the importance of trafficking and targeting of ion channels to cardiac function. A major challenge in the field is to understand how these and other actors work together in intact myocytes to fine-tune ion channel expression and control cardiac excitability.
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Affiliation(s)
- Elise Balse
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David F. Steele
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Hugues Abriel
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Alain Coulombe
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David Fedida
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Stéphane N. Hatem
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
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26
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Fong JT, Kells RM, Gumpert AM, Marzillier JY, Davidson MW, Falk MM. Internalized gap junctions are degraded by autophagy. Autophagy 2012; 8:794-811. [PMID: 22635056 PMCID: PMC3378421 DOI: 10.4161/auto.19390] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Direct intercellular communication mediated by gap junctions (GJs) is a hallmark of normal cell and tissue physiology. In addition, GJs significantly contribute to physical cell-cell adhesion. Clearly, these cellular functions require precise modulation. Typically, GJs represent arrays of hundreds to thousands of densely packed channels, each one assembled from two half-channels (connexons), that dock head-on in the extracellular space to form the channel arrays that link neighboring cells together. Interestingly, docked GJ channels cannot be separated into connexons under physiological conditions, posing potential challenges to GJ channel renewal and physical cell-cell separation. We described previously that cells continuously—and effectively after treatment with natural inflammatory mediators—internalize their GJs in an endo-/exocytosis process that utilizes clathrin-mediated endocytosis components, thus enabling these critical cellular functions. GJ internalization generates characteristic cytoplasmic double-membrane vesicles, described and termed earlier annular GJs (AGJs) or connexosomes. Here, using expression of the major fluorescent-tagged GJ protein, connexin 43 (Cx43-GFP/YFP/mApple) in HeLa cells, analysis of endogenously expressed Cx43, ultrastructural analyses, confocal colocalization microscopy, pharmacological and molecular biological RNAi approaches depleting cells of key-autophagic proteins, we provide compelling evidence that GJs, following internalization, are degraded by autophagy. The ubiquitin-binding protein p62/sequestosome 1 was identified in targeting internalized GJs to autophagic degradation. While previous studies identified proteasomal and endo-/lysosomal pathways in Cx43 and GJ degradation, our study provides novel molecular and mechanistic insights into an alternative GJ degradation pathway. Its recent link to health and disease lends additional importance to this GJ degradation mechanism and to autophagy in general.
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Affiliation(s)
- John T Fong
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
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The involvement of gap junctions in the delayed phase of the protection induced by cardiac pacing in dogs. Clin Sci (Lond) 2012; 123:39-51. [DOI: 10.1042/cs20110501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study has examined the role of GJ (gap junctions) in the delayed anti-arrhythmic effect of cardiac pacing, with particular reference to the time-course changes in Cx43 (connexin43) expression both after pacing (4×5 min, at a rate of 240 beats/min) and 24 h later, when the dogs were subjected to a 25 min occlusion and reperfusion of the LAD (left anterior descending coronary artery). Compared with the SP (sham-paced) controls (n=20), in dogs paced 24 h previously (n=16) there were reductions in arrhythmia severity [e.g. number of VPB (ventricular premature beats) during occlusion 294±78 compared with 63±25; survival from the combined ischaemia/reperfusion insult 20% compared with 78%], and in other ischaemic changes [epicardial ST-segment, TAT (total activation time) and tissue impedance]. Pacing also prevented the ischaemia-induced structural impairment of the intercalated discs, and preserved GJ permeability and Cx43 phosphorylation, without modifying Cx43 protein content. Following cardiac pacing the membrane and total Cx43 protein contents were unchanged up to 6 h, but were significantly reduced 12 h later (preceded by a down-regulation of Cx43 mRNA at 6 h), and returned to normal by 24 h. Interestingly, dogs that were subjected to ischaemia 12 h after cardiac pacing showed increased arrhythmia generation. We conclude that cardiac pacing results in time-dependent changes in Cx43 expression, which may alter GJ function and influence arrhythmia generation during a subsequent ischaemia/reperfusion insult. This effect is manifested in protection 24 h after pacing, but of potential clinical interest is the finding that there is a time interval after pacing during which an ischaemic event may generate severe ventricular arrhythmias.
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Smyth JW, Vogan JM, Buch PJ, Zhang SS, Fong TS, Hong TT, Shaw RM. Actin cytoskeleton rest stops regulate anterograde traffic of connexin 43 vesicles to the plasma membrane. Circ Res 2012; 110:978-89. [PMID: 22328533 DOI: 10.1161/circresaha.111.257964] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE The intracellular trafficking of connexin 43 (Cx43) hemichannels presents opportunities to regulate cardiomyocyte gap junction coupling. Although it is known that Cx43 hemichannels are transported along microtubules to the plasma membrane, the role of actin in Cx43 forward trafficking is unknown. OBJECTIVE We explored whether the actin cytoskeleton is involved in Cx43 forward trafficking. METHODS AND RESULTS High-resolution imaging reveals that Cx43 vesicles colocalize with nonsarcomeric actin in adult cardiomyocytes. Live-cell fluorescence imaging reveals Cx43 vesicles as stationary or traveling slowly (average speed 0.09 μm/s) when associated with actin. At any time, the majority (81.7%) of vesicles travel at subkinesin rates, suggesting that actin is important for Cx43 transport. Using Cx43 containing a hemagglutinin tag in the second extracellular loop, we developed an assay to detect transport of de novo Cx43 hemichannels to the plasma membrane after release from Brefeldin A-induced endoplasmic reticulum/Golgi vesicular transport block. Latrunculin A (for specific interference of actin) was used as an intervention after reinitiation of vesicular transport. Disruption of actin inhibits delivery of Cx43 to the cell surface. Moreover, using the assay in primary cardiomyocytes, actin inhibition causes an 82% decrease (P<0.01) in de novo endogenous Cx43 delivery to cell-cell borders. In Langendorff-perfused mouse heart preparations, Cx43/β-actin complexing is disrupted during acute ischemia, and inhibition of actin polymerization is sufficient to reduce levels of Cx43 gap junctions at intercalated discs. CONCLUSIONS Actin is a necessary component of the cytoskeleton-based forward trafficking apparatus for Cx43. In cardiomyocytes, Cx43 vesicles spend a majority of their time pausing at nonsarcomeric actin rest stops when not undergoing microtubule-based transport to the plasma membrane. Deleterious effects on this interaction between Cx43 and the actin cytoskeleton during acute ischemia contribute to losses in Cx43 localization at intercalated discs.
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Affiliation(s)
- James W Smyth
- University of California San Francisco, Cardiovascular Research Institute, 555 Mission Bay Boulevard South, San Francisco, CA 94158, USA
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Abstract
The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.
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Affiliation(s)
- C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York, NY 10065, USA.
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Rosenhouse‐Dantsker A, Mehta D, Levitan I. Regulation of Ion Channels by Membrane Lipids. Compr Physiol 2012; 2:31-68. [DOI: 10.1002/cphy.c110001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Avila MA, Sell SL, Hawkins BE, Hellmich HL, Boone DR, Crookshanks JM, Prough DS, DeWitt DS. Cerebrovascular connexin expression: effects of traumatic brain injury. J Neurotrauma 2011; 28:1803-11. [PMID: 21895483 PMCID: PMC3172862 DOI: 10.1089/neu.2011.1900] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) results in dysfunction of the cerebrovasculature. Gap junctions coordinate vasomotor responses and evidence suggests that they are involved in cerebrovascular dysfunction after TBI. Gap junctions are comprised of connexin proteins (Cxs), of which Cx37, Cx40, Cx43, and Cx45 are expressed in vascular tissue. This study tests the hypothesis that TBI alters Cx mRNA and protein expression in cerebral vascular smooth muscle and endothelial cells. Anesthetized (1.5% isoflurane) male Sprague-Dawley rats received sham or fluid-percussion TBI. Two, 6, and 24 h after, cerebral arteries were harvested, fresh-frozen for RNA isolation, or homogenized for Western blot analysis. Cerebral vascular endothelial and smooth muscle cells were selected from frozen sections using laser capture microdissection. RNA was quantified by ribonuclease protection assay. The mRNA for all four Cx genes showed greater expression in the smooth muscle layer compared to the endothelial layer. Smooth muscle Cx43 mRNA expression was reduced 2 h and endothelial Cx45 mRNA expression was reduced 24 h after injury. Western blot analysis revealed that Cx40 protein expression increased, while Cx45 protein expression decreased 24 h after injury. These studies revealed significant changes in the mRNA and protein expression of specific vascular Cxs after TBI. This is the first demonstration of cell type-related differential expression of Cx mRNA in cerebral arteries, and is a first step in evaluating the effects of TBI on gap junction communication in the cerebrovasculature.
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Affiliation(s)
| | | | - Bridget E. Hawkins
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Helen L. Hellmich
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Debbie R. Boone
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Jeanna M. Crookshanks
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Donald S. Prough
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Douglas S. DeWitt
- Charles Allen Laboratories, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
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Márquez-Rosado L, Solan JL, Dunn CA, Norris RP, Lampe PD. Connexin43 phosphorylation in brain, cardiac, endothelial and epithelial tissues. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1985-92. [PMID: 21819962 DOI: 10.1016/j.bbamem.2011.07.028] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 07/14/2011] [Accepted: 07/19/2011] [Indexed: 11/30/2022]
Abstract
Gap junctions, composed of proteins from the connexin family, allow for intercellular communication between cells in essentially all tissues. There are 21 connexin genes in the human genome and different tissues express different connexin genes. Most connexins are known to be phosphoproteins. Phosphorylation can regulate connexin assembly into gap junctions, gap junction turnover and channel gating. Given the importance of gap junctions in development, proliferation and carcinogenesis, regulation of gap junction phosphorylation in response to wounding, hypoxia and other tissue insults is proving to be critical for cellular response and return to homeostasis. Connexin43 (Cx43) is the most widely and highly expressed gap junction protein, both in cell culture models and in humans, thus more research has been done on it and more reagents to it are available. In particular, antibodies that can report Cx43 phosphorylation status have been created allowing temporal examination of specific phosphorylation events in vivo. This review is focused on the use of these antibodies in tissue in situ, predominantly looking at Cx43 phosphorylation in brain, heart, endothelium and epithelium with reference to other connexins where data is available. These data allow us to begin to correlate specific phosphorylation events with changes in cell and tissue function. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Potential mechanisms of prospective antimigraine drugs: A focus on vascular (side) effects. Pharmacol Ther 2011; 129:332-51. [DOI: 10.1016/j.pharmthera.2010.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 11/09/2010] [Indexed: 12/13/2022]
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Nε-lysine acetylation determines dissociation from GAP junctions and lateralization of connexin 43 in normal and dystrophic heart. Proc Natl Acad Sci U S A 2011; 108:2795-800. [PMID: 21282606 DOI: 10.1073/pnas.1013124108] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wanting to explore the epigenetic basis of Duchenne cardiomyopathy, we found that global histone acetylase activity was abnormally elevated and the acetylase P300/CBP-associated factor (PCAF) coimmunoprecipitated with connexin 43 (Cx43), which was N(ε)-lysine acetylated and lateralized in mdx heart. This observation was paralleled by Cx43 dissociation from N-cadherin and zonula occludens 1, whereas pp60-c-Src association was unaltered. In vivo treatment of mdx with the pan-histone acetylase inhibitor anacardic acid significantly reduced Cx43 N(ε)-lysine acetylation and restored its association to GAP junctions (GJs) at intercalated discs. Noteworthy, in normal as well as mdx mice, the class IIa histone deacetylases 4 and 5 constitutively colocalized with Cx43 either at GJs or in the lateralized compartments. The class I histone deacetylase 3 was also part of the complex. Treatment of normal controls with the histone deacetylase pan-inhibitor suberoylanilide hydroxamic acid (MC1568) or the class IIa-selective inhibitor 3-{4-[3-(3-fluorophenyl)-3-oxo-1-propen-1-yl]-1-methyl-1H-pyrrol-2-yl}-N-hydroxy-2-propenamide (MC1568) determined Cx43 hyperacetylation, dissociation from GJs, and distribution along the long axis of ventricular cardiomyocytes. Consistently, the histone acetylase activator pentadecylidenemalonate 1b (SPV106) hyperacetylated cardiac proteins, including Cx43, which assumed a lateralized position that partly reproduced the dystrophic phenotype. In the presence of suberoylanilide hydroxamic acid, cell to cell permeability was significantly diminished, which is in agreement with a Cx43 close conformation in the consequence of hyperacetylation. Additional experiments, performed with Cx43 acetylation mutants, revealed, for the acetylated form of the molecule, a significant reduction in plasma membrane localization and a tendency to nuclear accumulation. These results suggest that Cx43 N(ε)-lysine acetylation may have physiopathological consequences for cell to cell coupling and cardiac function.
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Hayashi H. Does remodeling of gap junctions and connexin expression contribute to arrhythmogenesis? Study in an immobilization rat model. Circ J 2010; 74:2558-9. [PMID: 21088334 DOI: 10.1253/circj.cj-10-0983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Smyth JW, Shaw RM. Forward trafficking of ion channels: what the clinician needs to know. Heart Rhythm 2010; 7:1135-40. [PMID: 20621620 DOI: 10.1016/j.hrthm.2010.05.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 05/20/2010] [Indexed: 11/25/2022]
Abstract
Each heartbeat requires precisely orchestrated action potential propagation through the myocardium, achieved by coordination of about a million ion channels on the surface of each cardiomyocyte. Specific ion channels must occur within discrete subdomains of the sarcolemma to exert their electrophysiological effects with highest efficiency (e.g., voltage-gated Ca(2+) channels at T-tubules and gap junctions at intercalated discs). Regulation of ion channel movement to their appropriate membrane subdomain is an exciting research frontier with opportunity for novel therapeutic manipulation of ion channels in the treatment of heart disease. Although much research has generally focused on internalization and subsequent degradation of ion channels, the field of forward trafficking of de novo ion channels from the cell interior to the sarcolemma has now emerged as a key regulatory step in cardiac electrophysiological function. In this brief review, we provide an overview of the current understanding of the cellular biology governing the forward trafficking of ion channels.
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Affiliation(s)
- James W Smyth
- Cardiovascular Research Institute and Department of Medicine, University of California San Francisco, San Francisco, California, USA.
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The desmosomal plaque proteins of the plakophilin family. Dermatol Res Pract 2010; 2010:101452. [PMID: 20585595 PMCID: PMC2879962 DOI: 10.1155/2010/101452] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 01/26/2010] [Indexed: 11/18/2022] Open
Abstract
Three related proteins of the plakophilin family (PKP1_3) have been identified as junctional proteins that are essential for the formation and stabilization of desmosomal cell contacts. Failure of PKP expression can have fatal effects on desmosomal adhesion, leading to abnormal tissue and organ development. Thus, loss of functional PKP 1 in humans leads to ectodermal dysplasia/skin fragility (EDSF) syndrome, a genodermatosis with severe blistering of the epidermis as well as abnormal keratinocytes differentiation. Mutations in the human PKP 2 gene have been linked to severe heart abnormalities that lead to arrhythmogenic right ventricular cardiomyopathy (ARVC). In the past few years it has been shown that junctional adhesion is not the only function of PKPs. These proteins have been implicated in cell signaling, organization of the cytoskeleton, and control of protein biosynthesis under specific cellular circumstances. Clearly, PKPs are more than just cell adhesion proteins. In this paper we will give an overview of our current knowledge on the very distinct roles of plakophilins in the cell.
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