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Members of the AP-1 Family of Transcription Factors Regulate the Expression of Gja1 in Mouse GC-1 Spermatogonial Cells. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Gap junctions, mainly formed by Gja1 (Connexin43), play an essential role in the regulation of proliferation and differentiation of spermatogonia in the testis. Regulation of the abundance of Gja1 in spermatogonia involves various processes, including gene transcription, mRNA maturation, protein synthesis, post-translational modifications, plasma membrane integration and protein degradation. However, gene expression of Gja1 is abnormally decreased in most testicular germ cell tumors. Hence, a better understanding of the mechanisms of transcriptional regulation of Gja1 in spermatogonia is essential to understand how the loss of its expression occurs during the development of testicular cancer. As in other cell types, activator protein-1 (AP-1) transcription factors may be involved in such regulatory process. Thus, AP-1 members were overexpressed in GC-1 cells to assess their impact on Gja1 expression. We showed that Jun and Fosl2 cooperate to activate the Gja1 promoter in GC-1 cells. Furthermore, the recruitment of Jun to the proximal region (−153 to +46 bp) of the Gja1 promoter has been confirmed via chromatin immunoprecipitation. Protein kinase A and calcium-calmodulin protein kinase I also contribute to the activation of Gja1 expression by improving the cooperation between AP-1 factors. Therefore, the reduction in Gja1 expression in testicular germ cell tumors may involve a loss of cooperation between AP-1 factors.
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Abstract
Uterine fibroids (leiomyomas) are present in >75% of women and can cause serious morbidity. They are by far the leading cause of hysterectomy. Fibroids are a complex mixture of cells that include fibroblasts and smooth muscle cells. Rich in extracellular matrix, they typically arise through somatic mutations, most commonly MED12. Their lack of growth inhibition and their ability to have facets of malignancy yet be histologically and biologically benign provide opportunities to explore basic processes. To date, the mechanisms responsible for growth and development of leiomyomas are an enigma. This review provides an overview of current understanding and future directions for clinical and basic research of fibroids.
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Affiliation(s)
- Elizabeth A. Stewart
- 1Division of Reproductive Endocrinology and Infertility, Mayo Clinic, Rochester, Minnesota,2Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota,3Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota,4Department of Surgery, Mayo Clinic, Rochester, Minnesota,5Women’s Health Research Center, Mayo Clinic, Rochester, Minnesota
| | - Romana A. Nowak
- 6Department of Animal Sciences, University of Illinois, Urbana, Illinois,7Institute for Genomic Biology, University of Illinois, Urbana, Illinois
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Khader N, Shchuka VM, Shynlova O, Mitchell JA. Transcriptional control of parturition: insights from gene regulation studies in the myometrium. Mol Hum Reprod 2021; 27:gaab024. [PMID: 33823545 PMCID: PMC8126590 DOI: 10.1093/molehr/gaab024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/09/2021] [Indexed: 12/19/2022] Open
Abstract
The onset of labour is a culmination of a series of highly coordinated and preparatory physiological events that take place throughout the gestational period. In order to produce the associated contractions needed for foetal delivery, smooth muscle cells in the muscular layer of the uterus (i.e. myometrium) undergo a transition from quiescent to contractile phenotypes. Here, we present the current understanding of the roles transcription factors play in critical labour-associated gene expression changes as part of the molecular mechanistic basis for this transition. Consideration is given to both transcription factors that have been well-studied in a myometrial context, i.e. activator protein 1, progesterone receptors, oestrogen receptors, and nuclear factor kappa B, as well as additional transcription factors whose gestational event-driving contributions have been demonstrated more recently. These transcription factors may form pregnancy- and labour-associated transcriptional regulatory networks in the myometrium to modulate the timing of labour onset. A more thorough understanding of the transcription factor-mediated, labour-promoting regulatory pathways holds promise for the development of new therapeutic treatments that can be used for the prevention of preterm labour in at-risk women.
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Affiliation(s)
- Nawrah Khader
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Virlana M Shchuka
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Oksana Shynlova
- Lunenfeld Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Obstetrics & Gynaecology, University of Toronto, ON, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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Changes in Gastric Smooth Muscle Cell Contraction during Pregnancy: Effect of Estrogen. J Pregnancy 2019; 2019:4302309. [PMID: 31080672 PMCID: PMC6475543 DOI: 10.1155/2019/4302309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/14/2019] [Indexed: 12/19/2022] Open
Abstract
It is well known that pregnancy is associated with frequent gastrointestinal (GI) disorders and symptoms. Moreover, previous reports have shown that estrogen, which changes in levels during pregnancy, participates in the regulation of GI motility and is involved in the pathogenesis of various functional disorders in the stomach. The aim of the current study was to explore the changes in the expression of estrogen receptors (ERs) and examine the effect of estrogen on nitric oxide- (NO-) cyclic guanosine monophosphate (cGMP) pathway and thus relaxation in gastric smooth muscle cells (GSMC) during pregnancy. Single GSMC from early-pregnant and late-pregnant Sprague-Dawley rats were used. Protein and mRNA expression levels of ERs were measured via specifically designed enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), respectively. NO and cGMP levels were measured via specifically designed ELISA kits. Effect of estrogen on acetylcholine- (ACh-) induced contraction of single GSMC was measured via scanning micrometry in the presence or absence of the NO synthase inhibitor, N-nitro-L-arginine (L-NNA), or guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ). Estrogen increased both NO and cGMP levels and their levels were greater in early compared to late pregnancy. Expression of ERs was greater in early compared to late pregnancy. ACh induced greater contraction of GSMC in late pregnancy compared to early pregnancy. Estrogen inhibited ACh-induced contraction in both periods of pregnancy. Importantly, pretreatment of GSMC with either L-NNA or ODQ abolished estrogen inhibitory action on muscle contraction. In conclusion, GSMC contractile behavior undergoes drastic changes in response to estrogen during pregnancy and this might explain some of the pregnancy-associated gastric disorders.
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Aasen T, Johnstone S, Vidal-Brime L, Lynn KS, Koval M. Connexins: Synthesis, Post-Translational Modifications, and Trafficking in Health and Disease. Int J Mol Sci 2018; 19:ijms19051296. [PMID: 29701678 PMCID: PMC5983588 DOI: 10.3390/ijms19051296] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 02/06/2023] Open
Abstract
Connexins are tetraspan transmembrane proteins that form gap junctions and facilitate direct intercellular communication, a critical feature for the development, function, and homeostasis of tissues and organs. In addition, a growing number of gap junction-independent functions are being ascribed to these proteins. The connexin gene family is under extensive regulation at the transcriptional and post-transcriptional level, and undergoes numerous modifications at the protein level, including phosphorylation, which ultimately affects their trafficking, stability, and function. Here, we summarize these key regulatory events, with emphasis on how these affect connexin multifunctionality in health and disease.
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Affiliation(s)
- Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - Scott Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VI 22908, USA.
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, UK.
| | - Laia Vidal-Brime
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - K Sabrina Lynn
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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6
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Kavvadas P, Abed A, Poulain C, Authier F, Labéjof LP, Calmont A, Afieri C, Prakoura N, Dussaule JC, Chatziantoniou C, Chadjichristos CE. Decreased Expression of Connexin 43 Blunts the Progression of Experimental GN. J Am Soc Nephrol 2017; 28:2915-2930. [PMID: 28667079 DOI: 10.1681/asn.2016111211] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/05/2017] [Indexed: 11/03/2022] Open
Abstract
GN refers to a variety of renal pathologies that often progress to ESRD, but the molecular mechanisms underlying this progression remain incompletely characterized. Here, we determined whether dysregulated expression of the gap junction protein connexin 43, which has been observed in the progression of renal disease, contributes to GN progression. Immunostaining revealed de novo expression of connexin 43 in damaged glomeruli in patients with glomerular diseases as well as in mice after induction of experimental GN. Notably, 2 weeks after the induction of GN with nephrotoxic serum, mice with a heterozygous deletion of the connexin 43 gene (connexin 43+/-) had proteinuria, BUN, and serum creatinine levels significantly lower than those of wild-type animals. Additionally, the connexin 43+/- mice showed less crescent formation, tubular dilation, monocyte infiltration, and interstitial renal fibrosis. Treatment of cultured podocytes with connexin 43-specific blocking peptides attenuated TGF-β-induced cytoskeletal and morphologic changes and apoptosis as did treatment with the purinergic blocker suramin. Finally, therapeutic treatment of GN mice with connexin 43-specific antisense oligodeoxynucleotide improved functional and structural renal parameters. These findings suggest that crosstalk between connexin 43 and purinergic signaling contributes to podocyte damage in GN. Given that this protein is highly induced in individuals with glomerular diseases, connexin 43 may be a novel target for therapeutic treatment of GN.
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Affiliation(s)
- Panagiotis Kavvadas
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France
| | - Ahmed Abed
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,Sorbonne Universites, University Pierre et Marie Curie University Paris 6, Paris, France
| | - Coralie Poulain
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,University René Descartes, Paris, France.,University Denis Diderot, Paris, France
| | - Florence Authier
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France
| | - Lise-Paule Labéjof
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
| | - Amelie Calmont
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France
| | - Carlo Afieri
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,Unit of Nephrology Dialysis and Kidney Transplantation, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Ca Granda Ospedale Maggiore Policlinico di Milano, Milan, Italy; and
| | - Niki Prakoura
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France
| | - Jean-Claude Dussaule
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,Sorbonne Universites, University Pierre et Marie Curie University Paris 6, Paris, France.,Department of Physiology, Saint Antoine Hospital, Paris, France
| | - Christos Chatziantoniou
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France.,Sorbonne Universites, University Pierre et Marie Curie University Paris 6, Paris, France
| | - Christos E Chadjichristos
- National Institute for Health and Medical Research Unité Mixte de Recherche-S1155, Batiment Recherche, Tenon Hospital, Paris, France; .,Sorbonne Universites, University Pierre et Marie Curie University Paris 6, Paris, France
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7
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Zhang XF, Cui X. Connexin 43: Key roles in the skin. Biomed Rep 2017; 6:605-611. [PMID: 28584630 DOI: 10.3892/br.2017.903] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/17/2017] [Indexed: 12/26/2022] Open
Abstract
Gap junctions are tightly packed intercellular channels that serve a common purpose of allowing the intercellular exchange of small metabolites, second messengers and electrical signals. Connexins (Cxs) are gap junction proteins. Currently, 20 and 21 members of Cxs have been characterized in mice and humans, respectively. Connexin 43 (Cx43) is the most ubiquitously expressed type of Cx in the skin. It is produced by various different types of skin cell, such as keratinocytes, fibroblasts, endothelial and basal cells, melanocytes and dermal papilla cells. At present, more evidence indicates that Cx43 has an important role in skin repair and skin tumor development, as well as in skin cell invasion and metastasis. In this review, current knowledge regarding the regulation and function of Cx43 is summarized and the therapeutic potential of regulating Cx43 activity is discussed.
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Affiliation(s)
- Xiao-Fei Zhang
- Department of Biological Sciences and Biotechnology, School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, Hubei 430070, P.R. China
| | - Xiaofeng Cui
- Department of Biological Sciences and Biotechnology, School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, Hubei 430070, P.R. China
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Longchamp A, Allagnat F, Alonso F, Kuppler C, Dubuis C, Ozaki CK, Mitchell JR, Berceli S, Corpataux JM, Déglise S, Haefliger JA. Connexin43 Inhibition Prevents Human Vein Grafts Intimal Hyperplasia. PLoS One 2015; 10:e0138847. [PMID: 26398895 PMCID: PMC4580578 DOI: 10.1371/journal.pone.0138847] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/04/2015] [Indexed: 12/12/2022] Open
Abstract
Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment.
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Affiliation(s)
- Alban Longchamp
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Florent Allagnat
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Florian Alonso
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Christopher Kuppler
- Malcom Randall Veterans Affairs Medical Center and the Division of Vascular and Endovascular Surgery, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Céline Dubuis
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Charles-Keith Ozaki
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - James R. Mitchell
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Scott Berceli
- Malcom Randall Veterans Affairs Medical Center and the Division of Vascular and Endovascular Surgery, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Jean-Marc Corpataux
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Sébastien Déglise
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Jacques-Antoine Haefliger
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
- * E-mail:
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MacIntyre DA, Lee YS, Migale R, Herbert BR, Waddington SN, Peebles D, Hagberg H, Johnson MR, Bennett PR. Activator protein 1 is a key terminal mediator of inflammation-induced preterm labor in mice. FASEB J 2014; 28:2358-68. [PMID: 24497579 DOI: 10.1096/fj.13-247783] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Activation of uterine inflammatory pathways leads to preterm labor (PTL), associated with high rates of neonatal mortality and morbidity. The transcription factors nuclear factor κB (NFκB) and activator protein 1 (AP-1) regulate key proinflammatory and procontractile genes involved in normal labor and PTL. Here we show that NFκB activation normally occurs in the mouse myometrium at gestation day E18, prior to labor, whereas AP-1 and JNK activation occurs at labor onset. Where labor was induced using the progesterone receptor antagonist RU486, NFkB and AP-1/JNK activation both occurred at the time of labor (20 h compared to 60 h in DMSO-treated controls). Using an LPS (Escherichia coli: serotype O111)-induced PTL model that selectively activates AP-1 but not NFkB, we show that myometrial AP-1 activation drives production of cytokines (Il-6, Il-8, and Il-1β), metalloproteinases (Mmp3 and Mmp10), and procontractile proteins (Cox-2 and Cx43) resulting in PTL after 7 h. Protein levels of CX43 and IL-1β, and IL-1β cleavage, were increased following LPS-induced activation of AP-1. Inhibition of JNK by SP600125 (30 mg/kg) delayed PTL by 6 h (7.5 vs. 13.5 h P<0.05). Our data reveal that NFκB activation is not a functional requirement for infection/inflammation-induced preterm labor and that AP-1 activation is sufficient to drive inflammatory pathways that cause PTL.
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Affiliation(s)
- David A MacIntyre
- 2Imperial College Parturition Research Group, Institute of Reproduction and Developmental Biology, Imperial College London, Hammersmith Campus, London, W12 0NN, UK.
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10
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Firestone GL, Kapadia BJ. Minireview: regulation of gap junction dynamics by nuclear hormone receptors and their ligands. Mol Endocrinol 2012; 26:1798-807. [PMID: 22935924 DOI: 10.1210/me.2012-1065] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gap junctions are plasma membrane channels comprising connexin proteins that mediate intercellular permeability and communication. The presence, composition, and function of gap junctions can be regulated by diverse sets of physiological signals. Evidence from many hormone-responsive tissues has shown that connexin expression, modification, stability, and localization can be targeted by nuclear hormone receptors and their ligands through both transcriptional and nontranscriptional mechanisms. The focus of this review is to discuss molecular, cellular, and physiological studies that directly link receptor- and ligand-triggered signaling pathways to the regulation of gap junction dynamics.
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Affiliation(s)
- Gary L Firestone
- Department of Molecular and Cell Biology, 591 LSA, The University of California at Berkeley, Berkeley, California 94720-3200, USA.
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11
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Sharkey JT, Puttaramu R, Word RA, Olcese J. Melatonin synergizes with oxytocin to enhance contractility of human myometrial smooth muscle cells. J Clin Endocrinol Metab 2009; 94:421-7. [PMID: 19001515 PMCID: PMC2730229 DOI: 10.1210/jc.2008-1723] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CONTEXT Studies have shown that labor occurs primarily in the night/morning hours. Recently, we identified the human myometrium as a target for melatonin (MEL), the neuroendocrine output signal coding for circadian night. OBJECTIVE The purpose of this study was to determine the effects of MEL on contractility and the contractile machinery in telomerase-immortalized human myometrial cells. DESIGN To ascertain the effect of MEL on myometrial contractility in vitro, we performed gel retraction assays with cells exposed to iodomelatonin +/- oxytocin (OT). The effects of iodomelatonin on gap junctions were also investigated. Additionally, expression levels of the type 2 MEL receptor (MT2R) were assessed in myometrial biopsies from term pregnant women with or without labor. RESULTS MEL was found to synergistically enhance OT-induced contractility via the MT2R, which is coupled to a protein kinase C-dependent increase in phosphorylation of the myosin light chain protein. MT2R expression was markedly elevated in samples from pregnant women who had entered labor, as compared to matched nonlaboring pregnant women. MEL increased expression of the gap junction protein, connexin 43. In vitro dye spread assays showed that MEL-treated cells displayed substantially increased intercellular coupling. Increases in connexin 43 mRNA and cell to cell coupling were also found to be mediated via the MT2R in a protein kinase C-dependent manner. CONCLUSIONS MEL synergizes with OT to promote myometrial cell contractions and to facilitate gap junction activity in vitro. Such a synergy in vivo would promote coordinated and forceful contractions of the late term pregnant uterus necessary for parturition.
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MESH Headings
- Cells, Cultured
- Connexin 43/genetics
- Connexin 43/metabolism
- Drug Synergism
- Female
- Gene Expression Regulation/drug effects
- Humans
- Labor, Obstetric/metabolism
- Labor, Obstetric/physiology
- Melatonin/metabolism
- Melatonin/pharmacology
- Models, Biological
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/physiology
- Myometrium/drug effects
- Myometrium/metabolism
- Myometrium/physiology
- Oxytocin/metabolism
- Oxytocin/pharmacology
- Parturition/metabolism
- Parturition/physiology
- Pregnancy
- Receptor, Melatonin, MT1/metabolism
- Receptor, Melatonin, MT2/metabolism
- Receptors, Oxytocin/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Uterine Contraction/drug effects
- Uterine Contraction/metabolism
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Affiliation(s)
- James T Sharkey
- Florida State University College of Medicine, Tallahassee, Florida 32306-4300, USA
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12
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Helguera G, Eghbali M, Sforza D, Minosyan TY, Toro L, Stefani E. Changes in global gene expression in rat myometrium in transition from late pregnancy to parturition. Physiol Genomics 2008; 36:89-97. [PMID: 19001510 DOI: 10.1152/physiolgenomics.00290.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The process of parturition involves the complex interplay of factors that change the excitability and contractile activity of the uterus. We have compared the relative gene expression profile of myometrium from rats before parturition (21 days pregnant) and during delivery, using high-density DNA microarray. Of 8,740 sequences available in the array, a total of 3,782 were detected as present. From the sequences that were significantly altered, 59 genes were upregulated and 82 genes were downregulated. We were able to detect changes in genes described to have altered expression level at term, including connexin 43 and 26, cyclooxygenase 2, and oxytocin receptor, as well as novel genes that have been not previously associated with parturition. Quantitative real-time PCR on selected genes further confirmed the microarray data. Here we report for the first time that aquaporin5 (AQP5), a member of the aquaporin water channel family, was dramatically downregulated during parturition (approximately 100-fold by microarray and approximately 50-fold by real-time PCR). The emerging profile highlights biochemical cascades occurring in a period of approximately 36 h that trigger parturition and the initiation of myometrium reverse remodeling postpartum. The microarray analysis uncovered genes that were previously suspected to play a role in parturition. This regulation involves genes from immune/inflammatory response, steroid/lipid metabolism, calcium homeostasis, cell volume regulation, cell signaling, cell division, and tissue remodeling, suggesting the presence of multiple and redundant mechanisms altered in the process of birth.
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Affiliation(s)
- Gustavo Helguera
- Division of Molecular Medicine, Department of Anesthesiology, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, CA 90095-7115, USA
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13
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Abstract
Evaluation of the human genome suggests that all members of the connexin family of gap-junction proteins have now been successfully identified. This large and diverse family of proteins facilitates a number of vital cellular functions coupled with their roles, which range from the intercellular propagation of electrical signals to the selective intercellular passage of small regulatory molecules. Importantly, the extent of gap-junctional intercellular communication is under the direct control of regulatory events associated with channel assembly and turnover, as the vast majority of connexins have remarkably short half-lives of only a few hours. Since most cell types express multiple members of the connexin family, compensatory mechanisms exist to salvage tissue function in cases when one connexin is mutated or lost. However, numerous studies of the last decade have revealed that mutations in connexin genes can also lead to severe and debilitating diseases. In many cases, single point mutations lead to dramatic effects on connexin trafficking, assembly and channel function. This review will assess the current understanding of wild-type and selected disease-linked mutant connexin transport through the secretory pathway, gap-junction assembly at the cell surface, internalization and degradation.
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Affiliation(s)
- Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada N6A 5C1.
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