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Zappalà A, Romano IR, D’Angeli F, Musumeci G, Lo Furno D, Giuffrida R, Mannino G. Functional Roles of Connexins and Gap Junctions in Osteo-Chondral Cellular Components. Int J Mol Sci 2023; 24:ijms24044156. [PMID: 36835567 PMCID: PMC9967557 DOI: 10.3390/ijms24044156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Gap junctions (GJs) formed by connexins (Cxs) play an important role in the intercellular communication within most body tissues. In this paper, we focus on GJs and Cxs present in skeletal tissues. Cx43 is the most expressed connexin, participating in the formation of both GJs for intercellular communication and hemichannels (HCs) for communication with the external environment. Through GJs in long dendritic-like cytoplasmic processes, osteocytes embedded in deep lacunae are able to form a functional syncytium not only with neighboring osteocytes but also with bone cells located at the bone surface, despite the surrounding mineralized matrix. The functional syncytium allows a coordinated cell activity through the wide propagation of calcium waves, nutrients and anabolic and/or catabolic factors. Acting as mechanosensors, osteocytes are able to transduce mechanical stimuli into biological signals that spread through the syncytium to orchestrate bone remodeling. The fundamental role of Cxs and GJs is confirmed by a plethora of investigations that have highlighted how up- and downregulation of Cxs and GJs critically influence skeletal development and cartilage functions. A better knowledge of GJ and Cx mechanisms in physiological and pathological conditions might help in developing therapeutic approaches aimed at the treatment of human skeletal system disorders.
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Affiliation(s)
- Agata Zappalà
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Ivana Roberta Romano
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Floriana D’Angeli
- Department of Human Sciences and Quality of Life Promotion, San Raffaele Roma Open University, 00166 Rome, Italy
| | - Giuseppe Musumeci
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Debora Lo Furno
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Correspondence: (D.L.F.); (R.G.)
| | - Rosario Giuffrida
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Correspondence: (D.L.F.); (R.G.)
| | - Giuliana Mannino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98122 Messina, Italy
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Martin EA, Lasseigne AM, Miller AC. Understanding the Molecular and Cell Biological Mechanisms of Electrical Synapse Formation. Front Neuroanat 2020; 14:12. [PMID: 32372919 PMCID: PMC7179694 DOI: 10.3389/fnana.2020.00012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/09/2020] [Indexed: 12/20/2022] Open
Abstract
In this review article, we will describe the recent advances made towards understanding the molecular and cell biological mechanisms of electrical synapse formation. New evidence indicates that electrical synapses, which are gap junctions between neurons, can have complex molecular compositions including protein asymmetries across joined cells, diverse morphological arrangements, and overlooked similarities with other junctions, all of which indicate new potential roles in neurodevelopmental disease. Aquatic organisms, and in particular the vertebrate zebrafish, have proven to be excellent models for elucidating the molecular mechanisms of electrical synapse formation. Zebrafish will serve as our main exemplar throughout this review and will be compared with other model organisms. We highlight the known cell biological processes that build neuronal gap junctions and compare these with the assemblies of adherens junctions, tight junctions, non-neuronal gap junctions, and chemical synapses to explore the unknown frontiers remaining in our understanding of the critical and ubiquitous electrical synapse.
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Affiliation(s)
- E Anne Martin
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - Abagael M Lasseigne
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - Adam C Miller
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
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Yang Y, Zhu J, Zhang T, Liu J, Li Y, Zhu Y, Xu L, Wang R, Su F, Ou Y, Wu Q. PHD-finger domain protein 5A functions as a novel oncoprotein in lung adenocarcinoma. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:65. [PMID: 29566713 PMCID: PMC5863814 DOI: 10.1186/s13046-018-0736-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 03/14/2018] [Indexed: 12/30/2022]
Abstract
BACKGROUND PHD-finger domain protein 5A (PHF5A) is a highly conserved small transcriptional regulator also involved in pre-mRNA splicing; however, its biological functions and molecular mechanisms in non-small cell lung cancer (NSCLC) have not yet been investigated. The purpose of this study was to determine the functional relevance and therapeutic potential of PHF5A in lung adenocarcinoma (LAC). METHODS The expression of PHF5A in LAC tissues and adjacent non-tumor (ANT) tissues was investigated using immunohistochemistry of a tissue microarray, qRT-PCR, western blot and bioinformatics. The function of PHF5A was determined using several in vitro assays and also in vivo assay by lentiviral vector-mediated PHF5A depletion in LAC cell lines. RESULTS PHF5A was highly upregulated in LAC tissues compared with the ANT counterparts, and closely associated with tumor progression and poor patient prognosis. These results were further confirmed by findings of the TCGA database. Moreover, functional studies demonstrated that PHF5A knockdown not only resulted in reduced cell proliferation, increased cell apoptosis, and cell cycle arrest, but also suppressed migration and invasion in LAC cells. PHF5A silencing was also found to inhibit LAC tumor growth in nude mice. Microarray and bioinformatics analyses revealed that PHF5A depletion led to dysregulation of multiple tumor signaling pathways; selected factors in key signaling pathways were verified in vitro. CONCLUSIONS The data suggest for the first time that PHF5A is an oncoprotein that contributes to LAC progression by regulating multiple signaling pathways, and may constitute a prognostic factor and potential new therapeutic target in NSCLC.
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Affiliation(s)
- Yan Yang
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China.
| | - Jian Zhu
- Department of Cardiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Tiantian Zhang
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Jing Liu
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Yumei Li
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Yue Zhu
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Lingjie Xu
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Rui Wang
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Fang Su
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China
| | - Yurong Ou
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, Anhui, People's Republic of China
| | - Qiong Wu
- Department of Medical Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, People's Republic of China.
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Cx43-Dependent Skeletal Phenotypes Are Mediated by Interactions between the Hapln1a-ECM and Sema3d during Fin Regeneration. PLoS One 2016; 11:e0148202. [PMID: 26828861 PMCID: PMC4734779 DOI: 10.1371/journal.pone.0148202] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 01/14/2016] [Indexed: 12/17/2022] Open
Abstract
Skeletal development is a tightly regulated process and requires proper communication between the cells for efficient exchange of information. Analysis of fin length mutants has revealed that the gap junction protein Connexin43 (Cx43) coordinates cell proliferation (growth) and joint formation (patterning) during zebrafish caudal fin regeneration. Previous studies have shown that the extra cellular matrix (ECM) protein Hyaluronan and Proteoglycan Link Protein1a (Hapln1a) is molecularly and functionally downstream of Cx43, and that hapln1a knockdown leads to reduction of the glycosaminoglycan hyaluronan. Here we find that the proteoglycan aggrecan is similarly reduced following Hapln1a knockdown. Notably, we demonstrate that both hyaluronan and aggrecan are required for growth and patterning. Moreover, we provide evidence that the Hapln1a-ECM stabilizes the secreted growth factor Semaphorin3d (Sema3d), which has been independently shown to mediate Cx43 dependent phenotypes during regeneration. Double knockdown of hapln1a and sema3d reveal synergistic interactions. Further, hapln1a knockdown phenotypes were rescued by Sema3d overexpression. Therefore, Hapln1a maintains the composition of specific components of the ECM, which appears to be required for the stabilization of at least one growth factor, Sema3d. We propose that the Hapln1a dependent ECM provides the required conditions for Sema3d stabilization and function. Interactions between the ECM and signaling molecules are complex and our study demonstrates the requirement for components of the Hapln1a-ECM for Sema3d signal transduction.
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Bhadra J, Iovine MK. Hsp47 mediates Cx43-dependent skeletal growth and patterning in the regenerating fin. Mech Dev 2015; 138 Pt 3:364-74. [DOI: 10.1016/j.mod.2015.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 06/08/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
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6
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Plotkin LI, Stains JP. Connexins and pannexins in the skeleton: gap junctions, hemichannels and more. Cell Mol Life Sci 2015; 72:2853-67. [PMID: 26091748 PMCID: PMC4503509 DOI: 10.1007/s00018-015-1963-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
Abstract
Regulation of bone homeostasis depends on the concerted actions of bone-forming osteoblasts and bone-resorbing osteoclasts, controlled by osteocytes, cells derived from osteoblasts surrounded by bone matrix. The control of differentiation, viability and function of bone cells relies on the presence of connexins. Connexin43 regulates the expression of genes required for osteoblast and osteoclast differentiation directly or by changing the levels of osteocytic genes, and connexin45 may oppose connexin43 actions in osteoblastic cells. Connexin37 is required for osteoclast differentiation and its deletion results in increased bone mass. Less is known on the role of connexins in cartilage, ligaments and tendons. Connexin43, connexin45, connexin32, connexin46 and connexin29 are expressed in chondrocytes, while connexin43 and connexin32 are expressed in ligaments and tendons. Similarly, although the expression of pannexin1, pannexin2 and pannexin3 has been demonstrated in bone and cartilage cells, their function in these tissues is not fully understood.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Dr., MS 5035, Indianapolis, IN, 46202, USA,
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7
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Connexins in migration during development and cancer. Dev Biol 2014; 401:143-51. [PMID: 25553982 DOI: 10.1016/j.ydbio.2014.12.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 12/12/2022]
Abstract
Connexins, the gap junction proteins, through their multitude of actions are implicated in a variety of cell processes during animal development and cancer. They allow direct or paracrine/autocrine cell communication through their channel and hemi-channel functions. They enable adhesion and interact with a plethora of signalling molecules. Here, we review the common themes in developmental and pathological processes and we focus in their involvement in cell migration in four different systems: neurons, astrocytes, neural crest and cancer.
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Duran I, Ruiz-Sánchez J, Santamaría JA, Marí-Beffa M. Holmgren's principle of delamination during fin skeletogenesis. Mech Dev 2014; 135:16-30. [PMID: 25460362 DOI: 10.1016/j.mod.2014.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 10/24/2022]
Abstract
During fin morphogenesis, several mesenchyme condensations occur to give rise to the dermal skeleton. Although each of them seems to create distinctive and unique structures, they all follow the premises of the same morphogenetic principle. Holmgren's principle of delamination was first proposed to describe the morphogenesis of skeletal elements of the cranium, but Jarvik extended it to the development of the fin exoskeleton. Since then, some cellular or molecular explanations, such as the "flypaper" model (Thorogood et al.), or the evolutionary description by Moss, have tried to clarify this topic. In this article, we review new data from zebrafish studies to meet these criteria described by Holmgren and other authors. The variety of cell lineages involved in these skeletogenic condensations sheds light on an open discussion of the contributions of mesoderm- versus neural crest-derived cell lineages to the development of the head and trunk skeleton. Moreover, we discuss emerging molecular studies that are disclosing conserved regulatory mechanisms for dermal skeletogenesis and similarities during fin development and regeneration, which may have important implications in the potential use of the zebrafish fin as a model for regenerative medicine.
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Affiliation(s)
- I Duran
- Laboratory of Bioengineering and Tissue Regeneration (LABRET), Department of Cell Biology, Genetics and Physiology, Biomedical Research Institute of Málaga (IBIMA), Faculty of Sciences, University of Málaga, 29071 Málaga, Spain; Department of Orthopedic Surgery, University of California, Los Angeles, CA 90095, USA; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 29071 Málaga, Spain.
| | - J Ruiz-Sánchez
- Laboratory of Bioengineering and Tissue Regeneration (LABRET), Department of Cell Biology, Genetics and Physiology, Biomedical Research Institute of Málaga (IBIMA), Faculty of Sciences, University of Málaga, 29071 Málaga, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 29071 Málaga, Spain
| | - J A Santamaría
- Laboratory of Bioengineering and Tissue Regeneration (LABRET), Department of Cell Biology, Genetics and Physiology, Biomedical Research Institute of Málaga (IBIMA), Faculty of Sciences, University of Málaga, 29071 Málaga, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 29071 Málaga, Spain
| | - M Marí-Beffa
- Laboratory of Bioengineering and Tissue Regeneration (LABRET), Department of Cell Biology, Genetics and Physiology, Biomedical Research Institute of Málaga (IBIMA), Faculty of Sciences, University of Málaga, 29071 Málaga, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 29071 Málaga, Spain.
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de Zwart-Storm EA, Martin PE, van Steensel MAM. Gap junction diseases of the skin: novel insights from new mutations. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Inhibition of Connexin 26/43 and Extracellular-Regulated Kinase Protein Plays a Critical Role in Melatonin Facilitated Gap Junctional Intercellular Communication in Hydrogen Peroxide-Treated HaCaT Keratinocyte Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:589365. [PMID: 23243457 PMCID: PMC3518788 DOI: 10.1155/2012/589365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 09/26/2012] [Indexed: 01/19/2023]
Abstract
Though melatonin was known to regulate gap junctional intercellular communication (GJIC) in chick astrocytes and mouse hepatocytes, the underlying mechanism by melatonin was not elucidated in hydrogen peroxide- (H2O2-) treated HaCaT keratinocyte cells until now. In the current study, though melatonin at 2 mM and hydrogen peroxide (H2O2) at 300 μM showed weak cytotoxicity in HaCaT keratinocyte cells, melatonin significantly suppressed the formation of reactive oxygen species (ROS) in H2O2-treated HaCaT cells compared to untreated controls. Also, the scrape-loading dye-transfer assay revealed that melatonin enhances the intercellular communication by introducing Lucifer Yellow into H2O2-treated cells. Furthermore, melatonin significantly enhanced the expression of connexin 26 (Cx26) and connexin 43 (Cx43) at mRNA and protein levels, but not that of connexin 30 (Cx30) in H2O2-treated HaCaT cells. Of note, melatonin attenuated the phosphorylation of extracellular signal-regulated protein kinases (ERKs) more than p38 MAPK or JNK in H2O2-treated HaCaT cells. Conversely, ERK inhibitor PD98059 promoted the intercellular communication in H2O2-treated HaCaT cells. Furthermore, combined treatment of melatonin (200 μM) and vitamin C (10 μg/mL) significantly reduced ROS production in H2O2-treated HaCaT cells. Overall, these findings support the scientific evidences that melatonin facilitates gap junctional intercellular communication in H2O2-treated HaCaT keratinocyte cells via inhibition of connexin 26/43 and ERK as a potent chemopreventive agent.
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11
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Ton QV, Iovine MK. Determining how defects in connexin43 cause skeletal disease. Genesis 2012; 51:75-82. [PMID: 23019186 DOI: 10.1002/dvg.22349] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 09/20/2012] [Indexed: 11/10/2022]
Abstract
Gap junction channels mediate direct cell-cell communication via the exchange of second messengers, ions, and metabolites from one cell to another. Mutations in several human connexin (cx) genes, the subunits of gap junction channels, disturb the development and function of multiple tissues/organs. In particular, appropriate function of Cx43 is required for skeletal development in all vertebrate model organisms. Importantly, it remains largely unclear how disruption of gap junctional intercellular communication causes developmental defects. Two groups have taken distinct approaches toward defining the tangible molecular changes occurring downstream of Cx43-based gap junctional communication. Here, these strategies for determining how Cx43 modulates downstream events relevant to skeletal morphogenesis were reviewed.
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Affiliation(s)
- Quynh V Ton
- Department of Biological Sciences, 111 Research Drive, Iacocca B217, Lehigh University, Bethlehem, PA, USA
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12
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Le Bouffant R, Souquet B, Duval N, Duquenne C, Hervé R, Frydman N, Robert B, Habert R, Livera G. Msx1 and Msx2 promote meiosis initiation. Development 2011; 138:5393-402. [PMID: 22071108 DOI: 10.1242/dev.068452] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanisms regulating germ line sex determination and meiosis initiation are poorly understood. Here, we provide evidence for the involvement of homeobox Msx transcription factors in foetal meiosis initiation in mammalian germ cells. Upon meiosis initiation, Msx1 and Msx2 genes are strongly expressed in the foetal ovary, possibly stimulated by soluble factors found there: bone morphogenetic proteins Bmp2 and Bmp4, and retinoic acid. Analysis of Msx1/Msx2 double mutant embryos revealed a majority of undifferentiated germ cells remaining in the ovary and, importantly, a decrease in the number of meiotic cells. In vivo, the Msx1/Msx2 double-null mutation prevented full activation of Stra8, a gene required for meiosis. In F9 cells, Msx1 can bind to Stra8 regulatory sequences and Msx1 overexpression stimulates Stra8 transcription. Collectively, our data demonstrate for the first time that some homeobox genes are required for meiosis initiation in the female germ line.
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Affiliation(s)
- Ronan Le Bouffant
- CEA, DSV/iRCM/SCSR/LDG, Laboratoire de Développement des Gonades, Unité Cellules Souches et Radiation, F-92265 Fontenay aux Roses, France
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Batra N, Kar R, Jiang JX. Gap junctions and hemichannels in signal transmission, function and development of bone. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1909-18. [PMID: 21963408 DOI: 10.1016/j.bbamem.2011.09.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 09/03/2011] [Accepted: 09/15/2011] [Indexed: 10/17/2022]
Abstract
Gap junctional intercellular communication (GJIC) mediated by connexins, in particular connexin 43 (Cx43), plays important roles in regulating signal transmission among different bone cells and thereby regulates development, differentiation, modeling and remodeling of the bone. GJIC regulates osteoblast formation, differentiation, survival and apoptosis. Osteoclast formation and resorptive ability are also reported to be modulated by GJIC. Furthermore, osteocytes utilize GJIC to coordinate bone remodeling in response to anabolic factors and mechanical loading. Apart from gap junctions, connexins also form hemichannels, which are localized on the cell surface and function independently of the gap junction channels. Both these channels mediate the transfer of molecules smaller than 1.2kDa including small ions, metabolites, ATP, prostaglandin and IP(3). The biological importance of the communication mediated by connexin-forming channels in bone development is revealed by the low bone mass and osteoblast dysfunction in the Cx43-null mice and the skeletal malformations observed in occulodentodigital dysplasia (ODDD) caused by mutations in the Cx43 gene. The current review summarizes the role of gap junctions and hemichannels in regulating signaling, function and development of bone cells. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Affiliation(s)
- Nidhi Batra
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, USA
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Mori R, Power KT, Wang CM, Martin P, Becker DL. Acute downregulation of connexin43 at wound sites leads to a reduced inflammatory response, enhanced keratinocyte proliferation and wound fibroblast migration. J Cell Sci 2007; 119:5193-203. [PMID: 17158921 DOI: 10.1242/jcs.03320] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Experimental downregulation of connexin43 (Cx43) expression at skin wound sites appears to markedly improve the rate and quality of healing, but the underlying mechanisms are currently unknown. Here, we have compared physiological and cell biological aspects of the repair process with and without Cx43 antisense oligodeoxynucleotide treatment. Treated wounds exhibited accelerated skin healing with significantly increased keratinocyte and fibroblast proliferation and migration. In vitro knockdown of Cx43 in a fibroblast wound-healing model also resulted in significantly faster healing, associated with increased mRNA for TGF-beta1, and collagen alpha1 and general collagen content at the wound site. Treated wounds showed enhanced formation of granulation tissue and maturation with more rapid angiogenesis, myofibroblast differentiation and wound contraction appeared to be advanced by 2-3 days. Recruitment of both neutrophils and macrophages was markedly reduced within treated wounds, concomitant with reduced leukocyte infiltration. In turn, mRNA levels of CC chemokine ligand 2 and TNF-alpha were reduced in the treated wound. These data suggest that, by reducing Cx43 protein with Cx43-specific antisense oligodeoxynucleotides at wound sites early in the skin healing process repair is enhanced, at least in part, by accelerating cell migration and proliferation, and by attenuating inflammation and the additional damage it can cause.
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Affiliation(s)
- Ryoichi Mori
- Department of Physiology, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK
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Levin M. Gap junctional communication in morphogenesis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2007; 94:186-206. [PMID: 17481700 PMCID: PMC2292839 DOI: 10.1016/j.pbiomolbio.2007.03.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Gap junctions permit the direct passage of small molecules from the cytosol of one cell to that of its neighbor, and thus form a system of cell-cell communication that exists alongside familiar secretion/receptor signaling. Because of the rich potential for regulation of junctional conductance, and directional and molecular gating (specificity), gap junctional communication (GJC) plays a crucial role in many aspects of normal tissue physiology. However, the most exciting role for GJC is in the regulation of information flow that takes place during embryonic development, regeneration, and tumor progression. The molecular mechanisms by which GJC establishes local and long-range instructive morphogenetic cues are just beginning to be understood. This review summarizes the current knowledge of the involvement of GJC in the patterning of both vertebrate and invertebrate systems and discusses in detail several morphogenetic systems in which the properties of this signaling have been molecularly characterized. One model consistent with existing data in the fields of vertebrate left-right patterning and anterior-posterior polarity in flatworm regeneration postulates electrophoretically guided movement of small molecule morphogens through long-range GJC paths. The discovery of mechanisms controlling embryonic and regenerative GJC-mediated signaling, and identification of the downstream targets of GJC-permeable molecules, represent exciting next areas of research in this fascinating field.
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Affiliation(s)
- Michael Levin
- Forsyth Center for Regenerative and Devlopmental Biology, Forsyth Institute, and Developmental Biology Department, Harvard School of Dental Medicine, Boston, MA 02115, USA.
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Pearson RA, Lüneborg NL, Becker DL, Mobbs P. Gap junctions modulate interkinetic nuclear movement in retinal progenitor cells. J Neurosci 2006; 25:10803-14. [PMID: 16291954 PMCID: PMC6725838 DOI: 10.1523/jneurosci.2312-05.2005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During early retinal development, progenitor cells must divide repeatedly to expand the progenitor pool. During G(1) and G(2) of the cell cycle, progenitor cell nuclei migrate back-and-forth across the proliferative zone in a process termed interkinetic nuclear movement. Because division can only occur at the ventricular surface, factors that affect the speed of nuclear movement could modulate the duration of the cell cycle. Gap-junctional coupling and gap junction-dependent Ca(2+) activity are common features of proliferating cells in the immature nervous system. Furthermore, both gap-junctional coupling and changes in [Ca(2+)](i) have been shown to be positively correlated with the migration of a number of immature cell types. Using time-lapse confocal microscopy, we describe the nature and rate of progenitor cell interkinetic nuclear movement. We show that nuclear movement is usually, but not always, associated with Ca(2+) transients and that buffering of these transients with BAPTA slows movement. Furthermore, we show for the first time that gap-junctional communication is an important requirement for the maintenance of normal nuclear movement in retinal progenitor cells. Conventional blockers of gap junctions and transfection of cells with dominant-negative constructs of connexin 43 (Cx43) and Cx43-specific antisense oligodeoxynucleotides (asODNs) all act to slow interkinetic nuclear movement. The gap junction mimetic peptide Gap26 also acts to slow movement, an effect that we show may be attributable to the blockade of gap junction hemichannels.
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Affiliation(s)
- Rachael A Pearson
- Department of Physiology, University College London, London WC1E 6BT, United Kingdom.
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Stains JP, Civitelli R. Gap junctions in skeletal development and function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1719:69-81. [PMID: 16359941 DOI: 10.1016/j.bbamem.2005.10.012] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 10/26/2005] [Accepted: 10/28/2005] [Indexed: 11/29/2022]
Abstract
Gap junctions play a critical role in the coordinated function and activity of nearly all of the skeletal cells. This is not surprising, given the elaborate orchestration of skeletal patterning, bone modeling and subsequent remodeling, as well as the mechanical stresses, strains and adaptive responses that the skeleton must accommodate. Much remains to be learned regarding the role of gap junctions and hemichannels in these processes. A common theme is that without connexins none of the cells of bone function properly. Thus, connexins play an important role in skeletal form and function.
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Affiliation(s)
- Joseph P Stains
- University of Maryland School of Medicine, Department of Orthopaedics, Baltimore, MD 21201, USA
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Stains JP, Civitelli R. Cell-cell interactions in regulating osteogenesis and osteoblast function. ACTA ACUST UNITED AC 2005; 75:72-80. [PMID: 15838921 DOI: 10.1002/bdrc.20034] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Endochondral bone formation requires an elaborate interplay among autocrine, paracrine, and endocrine signals, positional cues, and cell-cell contacts to mediate the complex three-dimensional architecture and function of the skeleton. Embryonic bone development occurs by migration, aggregation, and condensation of immature mesenchymal progenitor cells to form the cartilaginous anlage. Upon vascular invasion, the cartilaginous scaffold is colonized and subsequently mineralized by osteoblasts. Likewise, bone remodeling in the adult skeleton is a dynamic process that requires coordinated cellular activities among osteoblasts, osteocytes, and osteoclasts to maintain bone homeostasis. This review examines the role of cell-cell interactions mediated by adherens junctions formed by cadherins and communicative gap junctions formed by connexins in regulating bone development and osteogenic function.
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Affiliation(s)
- Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Pizard A, Burgon PG, Paul DL, Bruneau BG, Seidman CE, Seidman JG. Connexin 40, a target of transcription factor Tbx5, patterns wrist, digits, and sternum. Mol Cell Biol 2005; 25:5073-83. [PMID: 15923624 PMCID: PMC1140596 DOI: 10.1128/mcb.25.12.5073-5083.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2004] [Revised: 12/09/2004] [Accepted: 03/14/2005] [Indexed: 11/20/2022] Open
Abstract
Haploinsufficiency of T-box transcription factor 5 (TBX5) causes human Holt-Oram syndrome (HOS), a developmental disorder characterized by skeletal and heart malformations. Mice carrying a Tbx5 null allele (Tbx5(+/Delta)) have malformations in digits, wrists, and sternum joints, regions where Tbx5 is expressed. We demonstrate that mice deficient in connexin 40 (Cx40), a Tbx5-regulated gap junction component, shared axial and appendicular skeletal malformations with Tbx5(+/Delta) mice. Although no role in skeleton patterning has been described for gap junctions, we demonstrate here that Cx40 is involved in formation of specific joints, as well as bone shape. Even a 50% reduction in either Tbx5 or Cx40 produces bone abnormalities, demonstrating their crucial control over skeletal development. Further, we demonstrate that Tbx5 exerts in part its key regulatory role in bone growth and maturation by controlling via Cx40 the expression of Sox9 (a transcription factor essential for chondrogenesis and skeleton growth). Our study strongly suggests that Cx40 deficiency accounts for many skeletal malformations in HOS and that Tbx5 regulation of Cx40 plays a critical role in the exquisite developmental patterning of the forelimbs and sternum.
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Affiliation(s)
- Anne Pizard
- Department of Genetics, Harvard Medical School and Howard Hughes Medical Institute, Boston, MA 02115, USA
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20
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Abstract
Bone development (modeling) occurs by migration, aggregation, and condensation of immature osteo/chondroprogenitor cells to form the cartilaginous anlage. This process requires precisely controlled cell-cell interactions. Likewise, bone remodeling in the adult skeleton is a dynamic process that requires coordinated cellular activities among osteoblasts, osteocytes, and osteoclasts to maintain bone homeostasis. The cooperative nature of both bone modeling and remodeling requires tightly regulated mechanisms of intercellular recognition and communication that permit the cells to sort and migrate, synchronize activity, equalize hormonal responses, and diffuse locally generated signals. Osteoblasts and osteocytes achieve these interactions through cadherin-based adherens junctions as well as by formation of communicating junctions, gap junctions. This review examines the current knowledge of how direct cell-to-cell interactions modulate osteoblast function.
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Affiliation(s)
- Joseph P Stains
- Division of Bone and Mineral Diseases, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
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Nishimura T, Dunk C, Lu Y, Feng X, Gellhaus A, Winterhager E, Rossant J, Lye SJ. Gap junctions are required for trophoblast proliferation in early human placental development. Placenta 2004; 25:595-607. [PMID: 15193866 DOI: 10.1016/j.placenta.2004.01.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/07/2004] [Indexed: 10/26/2022]
Abstract
Little is known about the role of gap junctional intercellular communication (GJIC) in human trophoblast differentiation, particularly during the formation of extravillous trophoblast (EVT) cell columns and their subsequent differentiation into invasive cells. We have identified transcripts for five connexin gap junction proteins in the early human placenta (Cx32, Cx37, Cx40, Cx43 and Cx45). Of these, Cx40 and Cx45 proteins immunolocalize to EVT in anchoring cell columns. Cx40 expression is prominent in the anchoring column throughout the first trimester of pregnancy (6-14 weeks gestation). We used first trimester placental villous explant cultures to determine the functional significance of the inhibition of GJIC in EVT cell proliferation and differentiation using two known GJIC inhibitors, carbenoxolone (CBX) and heptanol. The morphology of EVT outgrowths changed dramatically upon GJIC-blockade, from compact and organized outgrowths into a scattered group of rounded individual trophoblast cells, reminiscent of an early invasive phenotype. Furthermore, the inhibition of GJIC in placental explants by CBX or heptanol induced a switch away from the proliferative and towards an invasive EVT phenotype, as evident from (a) the loss of the proliferation marker Ki67 and (b) an increase in the invasive marker alpha1 integrin. We also utilized antisense oligonucleotides to inhibit Cx40 protein expression in placental explants. Cx40 antisense treatment also resulted in the abolishment of outgrowth EVT cell proliferation (as determined by Ki67 immunostaining). Together, these results suggest that gap junctions composed particularly of Cx40 channels are required for the proliferation of EVT cells in anchoring cell columns, and that a loss of GJIC contributes to differentiation to the invasive EVT phenotype.
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Affiliation(s)
- T Nishimura
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada
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22
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Qiu C, Coutinho P, Frank S, Franke S, Law LY, Martin P, Green CR, Becker DL. Targeting connexin43 expression accelerates the rate of wound repair. Curr Biol 2004; 13:1697-703. [PMID: 14521835 DOI: 10.1016/j.cub.2003.09.007] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The repair of tissue damage is a key survival process in all organisms and involves the coordinated activation of several cell types. Cell-cell communication is clearly fundamental to this process, and a great deal is known about extracellular communication within the wound site via cytokines. Here we show that direct cell-cell communication through connexin 43 (Cx43) gap junction channels also plays a major role in the wound healing process. In two different wound healing models, incisional and excisional skin lesions, we show that a single topical application of Cx43 antisense gel brings about a transient downregulation of Cx43 protein levels, and this results in a dramatic increase in the rate of wound closure. Cx43 knockdown reduces inflammation, seen both macroscopically, as a reduction in swelling, redness, and wound gape, and microscopically, as a significant decrease in neutrophil numbers in the tissue around the wound. One long-term consequence of the improved rate of healing is a significant reduction in the extent of granulation tissue deposition and the subsequent formation of a smaller, less distorted, scar. This approach is likely to have widespread therapeutic applications in other injured tissues and opens up new avenues of research into improving the wound healing process.
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Affiliation(s)
- Cindy Qiu
- Department of Anatomy and Developmental Biology, University College London, Gower St., WC1E 6BT London, UK
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Fernández-Llebrez P, Grondona JM, Pérez J, López-Aranda MF, Estivill-Torrús G, Llebrez-Zayas PF, Soriano E, Ramos C, Lallemand Y, Bach A, Robert B. Msx1-Deficient Mice Fail to Form Prosomere 1 Derivatives, Subcommissural Organ, and Posterior Commissure and Develop Hydrocephalus. J Neuropathol Exp Neurol 2004; 63:574-86. [PMID: 15217086 DOI: 10.1093/jnen/63.6.574] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Msx1 is a regulatory gene involved in epithelio-mesenchymal interactions in limb formation and organogenesis. In the embryonic CNS, the Msx1 gene is expressed along the dorsal midline. Msx1 mutant mice have been obtained by insertion of the nlacZ gene in the Msx1 homeodomain. The most important features of homozygous mutants that we observed were the absence or malformation of the posterior commissure (PC) and of the subcommissural organ (SCO), the collapse of the cerebral aqueduct, and the development of hydrocephalus. Heterozygous mutants developed abnormal PC and reduced SCO, as revealed by specific antibodies against SCO secretory glycoproteins. About one third of the heterozygous mutants also showed hydrocephalus. Other defects displayed by homozygous mutants were ependymal denudation, subventricular cavitations and edema, and underdevelopment of the pineal gland and subfornical organ. Some homozygous mutants developed both SCO and PC, probably as a consequence of genetic redundancy with Msx2. However, these mutants did not show SCO-immunoreactive glycoproteins and displayed obstructive hydrocephalus. This suggests that Msx1 is necessary for the synthesis of SCO glycoproteins, which would then be required for the maintenance of an open aqueduct.
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Affiliation(s)
- P Fernández-Llebrez
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.
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Brown WRA, Hubbard SJ, Tickle C, Wilson SA. The chicken as a model for large-scale analysis of vertebrate gene function. Nat Rev Genet 2003; 4:87-98. [PMID: 12560806 DOI: 10.1038/nrg998] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- William R A Brown
- Institute of Genetics, Nottingham University, Queen's Medical Centre, Nottingham NG7 2UH, UK
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Law LY, Lin JS, Becker DL, Green CR. Knockdown of connexin43-mediated regulation of the zone of polarizing activity in the developing chick limb leads to digit truncation. Dev Growth Differ 2002; 44:537-47. [PMID: 12492512 DOI: 10.1046/j.1440-169x.2002.00666.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the developing chick wing, the use of antisense oligodeoxynucleotides to transiently knock down the expression of the gap junction protein, connexin43 (Cx43), results in limb patterning defects, including deletion of the anterior digits. To understand more about how such defects arise, the effects of transient Cx43 knockdown on the expression patterns of several genes known to play pivotal roles in limb formation were examined. Sonic hedgehog (Shh), which is normally expressed in the zone of polarizing activity (ZPA) and is required to maintain both the ZPA and the apical ectodermal ridge (AER), was found to be downregulated in treated limbs within 30 h. Bone morphogenetic protein-2 (Bmp-2), a gene downstream of Shh, was similarly downregulated. Fibroblast growth factor-8 expression, however, was unaltered 30 h after treatment but was greatly reduced at 48 h post-treatment, when the AER begins to regress. Expressions of Bmp-4 and Muscle segment homeobox-like gene (Msx-1) were not affected at any of the time points examined. Cx43 expression is therefore involved in some, but not all patterning cascades, and appears to play a role in the regulation of ZPA activity.
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Affiliation(s)
- Lee Yong Law
- Anatomy with Radiology, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand
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