201
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Fang WL, Lai SY, Lai WA, Lee MT, Liao CF, Ke FC, Hwang JJ. CRTC2 and Nedd4 ligase involvement in FSH and TGFβ1 upregulation of connexin43 gap junction. J Mol Endocrinol 2015; 55:263-75. [PMID: 26508620 DOI: 10.1530/jme-15-0076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The major mission of the ovarian follicle is the timely production of the mature fertilizable oocyte, and this is achieved by gonadotropin-regulated, gap junction-mediated cell-cell communication between the oocyte and surrounding nurturing granulosa cells. We have demonstrated that FSH and transforming growth factor beta 1 (TGFβ1) stimulate Gja1 gene-encoded connexin43 (Cx43) gap junction formation/function in rat ovarian granulosa cells is important for their induction of steroidogenesis; additionally, cAMP-protein kinase A (PKA)- and calcium-calcineurin-sensitive cAMP response element-binding (CREB) coactivator CRTC2 plays a crucial role during steroidogenesis. This study was to explore the potential molecular mechanism whereby FSH and TGFβ1 regulate Cx43 synthesis and degradation, particularly the involvement of CRTC2 and ubiquitin ligase Nedd4. Primary culture of granulosa cells from ovarian antral follicles of gonadotropin-primed immature rats was used. At 48 h post-treatment, FSH plus TGFβ1 increased Cx43 level and gap junction function in a PKA- and calcineurin-dependent manner, and TGFβ1 acting through its type I receptor modulated FSH action. Chromatin-immunoprecipitation analysis reveals FSH induced an early-phase (45 min) and FSH+TGFβ1 further elicited a late-phase (24 h) increase in CRTC2, CREB and CBP binding to the Gja1 promoter. Additionally, FSH+TGFβ1 increased the half-life of hyper-phosphorylated Cx43 (Cx43-P2). Also, the proteasome inhibitor MG132 prevented the brefeldin A (blocker of protein transport through Golgi)-reduced Cx43-P2 level and membrane Cx43 gap junction plaque. This is associated with FSH+TGFβ1-attenuated Cx43 interaction with Nedd4 and Cx43 ubiquitination. In all, this study uncovers that FSH and TGFβ1 upregulation of Cx43 gap junctions in ovarian granulosa cells critically involves enhancing CRTC2/CREB/CBP-mediated Cx43 expression and attenuating ubiquitin ligase Nedd4-mediated proteosomal degradation of Cx43 protein.
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Affiliation(s)
- Wei-Ling Fang
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Si-Yi Lai
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Wei-An Lai
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ming-Ting Lee
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ching-Fong Liao
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ferng-Chun Ke
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Jiuan-Jiuan Hwang
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
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202
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Yamada A, Futagi M, Fukumoto E, Saito K, Yoshizaki K, Ishikawa M, Arakaki M, Hino R, Sugawara Y, Ishikawa M, Naruse M, Miyazaki K, Nakamura T, Fukumoto S. Connexin 43 Is Necessary for Salivary Gland Branching Morphogenesis and FGF10-induced ERK1/2 Phosphorylation. J Biol Chem 2015; 291:904-12. [PMID: 26565022 DOI: 10.1074/jbc.m115.674663] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Indexed: 11/06/2022] Open
Abstract
Cell-cell interaction via the gap junction regulates cell growth and differentiation, leading to formation of organs of appropriate size and quality. To determine the role of connexin43 in salivary gland development, we analyzed its expression in developing submandibular glands (SMGs). Connexin43 (Cx43) was found to be expressed in salivary gland epithelium. In ex vivo organ cultures of SMGs, addition of the gap junctional inhibitors 18α-glycyrrhetinic acid (18α-GA) and oleamide inhibited SMG branching morphogenesis, suggesting that gap junctional communication contributes to salivary gland development. In Cx43(-/-) salivary glands, submandibular and sublingual gland size was reduced as compared with those from heterozygotes. The expression of Pdgfa, Pdgfb, Fgf7, and Fgf10, which induced branching of SMGs in Cx43(-/-) samples, were not changed as compared with those from heterozygotes. Furthermore, the blocking peptide for the hemichannel and gap junction channel showed inhibition of terminal bud branching. FGF10 induced branching morphogenesis, while it did not rescue the Cx43(-/-) phenotype, thus Cx43 may regulate FGF10 signaling during salivary gland development. FGF10 is expressed in salivary gland mesenchyme and regulates epithelial proliferation, and was shown to induce ERK1/2 phosphorylation in salivary epithelial cells, while ERK1/2 phosphorylation in HSY cells was dramatically inhibited by 18α-GA, a Cx43 peptide or siRNA. On the other hand, PDGF-AA and PDGF-BB separately induced ERK1/2 phosphorylation in primary cultured salivary mesenchymal cells regardless of the presence of 18α-GA. Together, our results suggest that Cx43 regulates FGF10-induced ERK1/2 phosphorylation in salivary epithelium but not in mesenchyme during the process of SMG branching morphogenesis.
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Affiliation(s)
- Aya Yamada
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Masaharu Futagi
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Emiko Fukumoto
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Kan Saito
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Keigo Yoshizaki
- Division of Orthodontics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Masaki Ishikawa
- Operative Dentistry, Department of Restorative Dentistry Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan and
| | - Makiko Arakaki
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Ryoko Hino
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Yu Sugawara
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Momoko Ishikawa
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Masahiro Naruse
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Kanako Miyazaki
- Division of Orthodontics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Takashi Nakamura
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences
| | - Satoshi Fukumoto
- From the Division of Pediatric Dentistry, Department of Oral Health and Development Sciences,
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203
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Nassal MMJ, Werdich AA, Wan X, Hoshi M, Deschênes I, Rosenbaum DS, Donahue JK. Phosphorylation at Connexin43 Serine-368 Is Necessary for Myocardial Conduction During Metabolic Stress. J Cardiovasc Electrophysiol 2015; 27:110-9. [PMID: 26459193 DOI: 10.1111/jce.12833] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/20/2015] [Accepted: 08/26/2015] [Indexed: 11/27/2022]
Abstract
Connexin43 (Cx43) phosphorylation alters gap junction localization and function. In particular, phosphorylation at serine-368 (S368) has been suggested to alter gap junctional conductance, but previous reports have shown inconsistent results for both timing and functional effects of S368 phosphorylation. The objective of this study was to determine the functional effects of isolated S368 phosphorylation. We evaluated wild-type Cx43 (AdCx43) and mutations simulating permanent phosphorylation (Ad368E) or preventing phosphorylation (Ad368A) at S368. Function was assessed by optical mapping of electrical conduction in patterned cultures of neonatal rat ventricular myocytes, under baseline and metabolic stress (MS) conditions. Baseline conduction velocity (CV) was similar for all groups. In the AdCx43 and Ad368E groups, MS moderately decreased CV. Ad368A caused complete conduction block during MS. Triton-X solubility assessment showed no change in Cx43 location during conduction impairment. Western blot analysis showed that Cx43-S368 phosphorylation was present at baseline, and that it decreased during MS. Our data indicate that phosphorylation at S368 does not affect CV under baseline conditions, and that preventing S368 phosphorylation makes Cx43 hypersensitive to MS. These results show the critical role of S368 phosphorylation during stress conditions.
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Affiliation(s)
- Michelle M J Nassal
- Heart and Vascular Research Center and Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Andreas A Werdich
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA
| | - Xiaoping Wan
- Heart and Vascular Research Center and Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Malcolm Hoshi
- Heart and Vascular Research Center and Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Isabelle Deschênes
- Heart and Vascular Research Center and Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - David S Rosenbaum
- Heart and Vascular Research Center and Department of Physiology & Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - J Kevin Donahue
- Division of Cardiology, University of Massachusetts Medical School, Worcester, MA, USA
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204
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Krabbe disease: involvement of connexin43 in the apoptotic effects of sphingolipid psychosine on mouse oligodendrocyte precursors. Apoptosis 2015; 21:25-35. [DOI: 10.1007/s10495-015-1183-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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205
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Riquelme MA, Burra S, Kar R, Lampe PD, Jiang JX. Mitogen-activated Protein Kinase (MAPK) Activated by Prostaglandin E2 Phosphorylates Connexin 43 and Closes Osteocytic Hemichannels in Response to Continuous Flow Shear Stress. J Biol Chem 2015; 290:28321-28328. [PMID: 26442583 DOI: 10.1074/jbc.m115.683417] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 01/04/2023] Open
Abstract
Cx43 hemichannels serve as a portal for the release of prostaglandins, a critical process in mediating biological responses of mechanical loading on bone formation and remodeling. We have previously observed that fluid flow shear stress (FFSS) opens hemichannels; however, sustained FFSS results in hemichannel closure, as continuous opening of hemichannels is detrimental to cell viability and bone remodeling. However, the mechanism that regulates the closure of the hemichannels is unknown. Here, we show that activation of p44/42 ERK upon continuous FFSS leads to Cx43 phosphorylation at Ser(279)-Ser(282), sites known to be phosphorylated sites by p44/42 MAPK. Incubation of osteocytic MLO-Y4 cells with conditioned media (CM) collected after continuous FFSS increased MAPK-dependent phosphorylation of Cx43. CM treatment inhibited hemichannel opening and this inhibition was reversed when cells were pretreated with the MAPK pathway inhibitor. We found that prostaglandin E2 (PGE2) accumulates in the CM in a time-dependent manner. Treatment with PGE2 increased phospho-p44/42 ERK levels and also Cx43 phosphorylation at Ser(279)-Ser(282) sites. Depletion of PGE2 from CM, and pre-treatment with a p44/42 ERK pathway-specific inhibitor, resulted in a complete inhibition of ERK-dependent Cx43 phosphorylation and attenuated the inhibition of hemichannels by CM and PGE2. Consistently, the opening of hemichannels by FFSS was blocked by PGE2 and CM and this blockage was reversed by U0126 and the CM depleted of PGE2. A similar observation was also obtained in isolated primary osteocytes. Together, results from this study suggest that extracellular PGE2 accumulated after continuous FFSS is responsible for activation of p44/42 ERK signaling and subsequently, direct Cx43 phosphorylation by activated ERK leads to hemichannel closure.
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Affiliation(s)
- Manuel A Riquelme
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Sirisha Burra
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Rekha Kar
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Jean X Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900.
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206
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Sun P, Dong L, MacDonald AI, Akbari S, Edward M, Hodgins MB, Johnstone SR, Graham SV. HPV16 E6 Controls the Gap Junction Protein Cx43 in Cervical Tumour Cells. Viruses 2015; 7:5243-56. [PMID: 26445057 PMCID: PMC4632379 DOI: 10.3390/v7102871] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 09/24/2015] [Accepted: 09/30/2015] [Indexed: 12/16/2022] Open
Abstract
Human papillomavirus type 16 (HPV16) causes a range of cancers including cervical and head and neck cancers. HPV E6 oncoprotein binds the cell polarity regulator hDlg (human homologue of Drosophila Discs Large). Previously we showed in vitro, and now in vivo, that hDlg also binds Connexin 43 (Cx43), a major component of gap junctions that mediate intercellular transfer of small molecules. In HPV16-positive non-tumour cervical epithelial cells (W12G) Cx43 localised to the plasma membrane, while in W12T tumour cells derived from these, it relocated with hDlg into the cytoplasm. We now provide evidence that E6 regulates this cytoplasmic pool of Cx43. E6 siRNA depletion in W12T cells resulted in restoration of Cx43 and hDlg trafficking to the cell membrane. In C33a HPV-negative cervical tumour cells expressing HPV16 or 18 E6, Cx43 was located primarily in the cytoplasm, but mutation of the 18E6 C-terminal hDlg binding motif resulted in redistribution of Cx43 to the membrane. The data indicate for the first time that increased cytoplasmic E6 levels associated with malignant progression alter Cx43 trafficking and recycling to the membrane and the E6/hDlg interaction may be involved. This suggests a novel E6-associated mechanism for changes in Cx43 trafficking in cervical tumour cells.
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Affiliation(s)
- Peng Sun
- Feinberg School of Medicine, North Western University, Chicago, IL 60611, USA.
| | - Li Dong
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Glasgow G61 1QH, Scotland, UK.
| | - Alasdair I MacDonald
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Glasgow G61 1QH, Scotland, UK.
| | - Shahrzad Akbari
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Glasgow G61 1QH, Scotland, UK.
| | - Michael Edward
- Dermatology, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, Scotland, UK.
| | - Malcolm B Hodgins
- Dermatology, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, Scotland, UK.
| | - Scott R Johnstone
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, Scotland, UK.
| | - Sheila V Graham
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Glasgow G61 1QH, Scotland, UK.
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207
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Vitale ML, Barry A. Biphasic Effect of Basic Fibroblast Growth Factor on Anterior Pituitary Folliculostellate TtT/GF Cell Coupling, and Connexin 43 Expression and Phosphorylation. J Neuroendocrinol 2015; 27:787-801. [PMID: 26265106 DOI: 10.1111/jne.12308] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/08/2015] [Accepted: 08/07/2015] [Indexed: 01/01/2023]
Abstract
Basic fibroblast growth factor (bFGF) is a mitogenic and differentiating cytokine. In the anterior pituitary, folliculostellate (FS) cells constitute the major source of bFGF. bFGF affects endocrine cell proliferation and secretion in the anterior pituitary. In addition, bFGF increases its own expression by acting directly on FS cells. FS cell Cx43-mediated gap junction intercellular communication allows the establishment of an intrapituitary network for the transmission of information. In the present study, we assessed how bFGF regulates FS cell coupling. Time course studies were carried out on the FS cell line TtT/GF. Short-term bFGF treatment induced a transient cell uncoupling and the phosphorylation in Ser368 of membrane-bound Cx43 without modifying Cx43 levels. We demonstrated the involvement of the protein kinase C (PKC) isoform α in the phosphorylation of Cx43 in S368. Moreover, we showed that bFGF induced PKCα activation by stimulating its expression, phosphorylation and association with the plasma membrane. The long-term incubation with bFGF increased TtT/GF cell coupling, total Cx43 levels and Cx43 accumulation at the cell membrane of cytoplasmic projections. The Cx43 level increase was a result of the stimulation of Cx43 gene transcription as mediated by the extracellular-regulated kinase 1/2 signalling pathway. Taken together, the data show that bFGF modulates TtT/GF cell coupling by activating different pathways that lead to opposite effects on Cx43 phosphorylation and expression depending on the duration of the exposure of the cells to bFGF. A short-term bFGF exposure reduces cell-to-cell communication as a mean of desynchronising FS cells. By contrast, long-term exposure to bFGF enhances cell-to-cell communication and facilitates coordination among FS cells.
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Affiliation(s)
- M L Vitale
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montreal, Québec, Canada
| | - A Barry
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montreal, Québec, Canada
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208
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Sharma P, Abbasi C, Lazic S, Teng ACT, Wang D, Dubois N, Ignatchenko V, Wong V, Liu J, Araki T, Tiburcy M, Ackerley C, Zimmermann WH, Hamilton R, Sun Y, Liu PP, Keller G, Stagljar I, Scott IC, Kislinger T, Gramolini AO. Evolutionarily conserved intercalated disc protein Tmem65 regulates cardiac conduction and connexin 43 function. Nat Commun 2015; 6:8391. [PMID: 26403541 DOI: 10.1038/ncomms9391] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 08/18/2015] [Indexed: 02/07/2023] Open
Abstract
Membrane proteins are crucial to heart function and development. Here we combine cationic silica-bead coating with shotgun proteomics to enrich for and identify plasma membrane-associated proteins from primary mouse neonatal and human fetal ventricular cardiomyocytes. We identify Tmem65 as a cardiac-enriched, intercalated disc protein that increases during development in both mouse and human hearts. Functional analysis of Tmem65 both in vitro using lentiviral shRNA-mediated knockdown in mouse cardiomyocytes and in vivo using morpholino-based knockdown in zebrafish show marked alterations in gap junction function and cardiac morphology. Molecular analyses suggest that Tmem65 interaction with connexin 43 (Cx43) is required for correct localization of Cx43 to the intercalated disc, since Tmem65 deletion results in marked internalization of Cx43, a shorter half-life through increased degradation, and loss of Cx43 function. Our data demonstrate that the membrane protein Tmem65 is an intercalated disc protein that interacts with and functionally regulates ventricular Cx43.
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Affiliation(s)
- Parveen Sharma
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Cynthia Abbasi
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Savo Lazic
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Allen C T Teng
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Dingyan Wang
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7
| | - Nicole Dubois
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Vladimir Ignatchenko
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Victoria Wong
- Departments of Molecular Genetics and Biochemistry, Donnelly Centre,, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Jun Liu
- Department of Mechanical and Industrial Engineering, Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada M5S 3G8
| | - Toshiyuki Araki
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Malte Tiburcy
- Institute of Pharmacology, University Medical Center Göttingen and DZHK (German Center for Cardiovascular Research) partner site Göttingen, Göttingen 37075, Germany
| | - Cameron Ackerley
- The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Wolfram H Zimmermann
- Institute of Pharmacology, University Medical Center Göttingen and DZHK (German Center for Cardiovascular Research) partner site Göttingen, Göttingen 37075, Germany
| | - Robert Hamilton
- The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, Advanced Micro and Nanosystems Laboratory, University of Toronto, Toronto, Ontario, Canada M5S 3G8
| | - Peter P Liu
- Toronto General Hospital, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Gordon Keller
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, Ontario, Canada M5G 1L7
| | - Igor Stagljar
- Departments of Molecular Genetics and Biochemistry, Donnelly Centre,, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Ian C Scott
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
| | - Thomas Kislinger
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada M5G 1L7.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9
| | - Anthony O Gramolini
- Department of Physiology, University of Toronto, Toronto General Hospital Research Institute, Toronto, Ontario, Canada M5G 1L7.,Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada M5G 1L7
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209
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Manipulating Cx43 expression triggers gene reprogramming events in dermal fibroblasts from oculodentodigital dysplasia patients. Biochem J 2015; 472:55-69. [PMID: 26349540 DOI: 10.1042/bj20150652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/08/2015] [Indexed: 02/06/2023]
Abstract
Oculodentodigital dysplasia (ODDD) is primarily an autosomal dominant disorder linked to over 70 GJA1 gene [connexin43 (Cx43)] mutations. For nearly a decade, our laboratory has been investigating the relationship between Cx43 and ODDD by expressing disease-linked mutants in reference cells, tissue-relevant cell lines, 3D organ cultures and by using genetically modified mouse models of human disease. Although salient features of Cx43 mutants have been revealed, these models do not necessarily reflect the complexity of the human context. To further overcome these limitations, we have acquired dermal fibroblasts from two ODDD-affected individuals harbouring D3N and V216L mutations in Cx43, along with familial controls. Using these ODDD patient dermal fibroblasts, which naturally produce less GJA1 gene product, along with RNAi and RNA activation (RNAa) approaches, we show that manipulating Cx43 expression triggers cellular gene reprogramming. Quantitative RT-PCR, Western blot and immunofluorescent analysis of ODDD patient fibroblasts show unusually high levels of extracellular matrix (ECM)-interacting proteins, including integrin α5β1, matrix metalloproteinases as well as secreted ECM proteins collagen-I and laminin. Cx43 knockdown in familial control cells produces similar effects on ECM expression, whereas Cx43 transcriptional up-regulation using RNAa decreases production of collagen-I. Interestingly, the enhanced levels of ECM-associated proteins in ODDD V216L fibroblasts is not only a consequence of increased ECM gene expression, but also due to an apparent deficit in collagen-I secretion which may further contribute to impaired collagen gel contraction in ODDD fibroblasts. These findings further illuminate the altered function of Cx43 in ODDD-affected individuals and highlight the impact of manipulating Cx43 expression in human cells.
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210
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Pidoux G, Taskén K. Anchored PKA as a gatekeeper for gap junctions. Commun Integr Biol 2015; 8:e1057361. [PMID: 26478781 PMCID: PMC4594474 DOI: 10.1080/19420889.2015.1057361] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 12/24/2022] Open
Abstract
Anchored protein kinase A (PKA) bound to A Kinase Anchoring Protein (AKAP) mediates effects of localized increases in cAMP in defined subcellular microdomains and retains the specificity in cAMP-PKA signaling to distinct extracellular stimuli. Gap junctions are pores between adjacent cells constituted by connexin proteins that provide means of communication and transfer of small molecules. While the PKA signaling is known to promote human trophoblast cell fusion, the gap junction communication through connexin 43 (Cx43) is a prerequisite for this process. We recently demonstrated that trophoblast fusion is regulated by ezrin, a known AKAP, which binds to Cx43 and delivers PKA in the vicinity gap junctions. We found that disruption of the ezrin-Cx43 interaction abolished PKA-dependent phosphorylation of Cx43 as well as gap junction communication and subsequently cell fusion. We propose that the PKA-ezrin-Cx43 macromolecular complex regulating gap junction communication constitutes a general mechanism to control opening of Cx43 gap junctions by phosphorylation in response to cAMP signaling in various cell types.
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Affiliation(s)
- Guillaume Pidoux
- INSERM; UMR-S-1139 ; Paris, France ; Université Paris Descartes ; Paris, France
| | - Kjetil Taskén
- Centre for Molecular Medicine Norway; Nordic EMBL Partnership; University of Oslo and Oslo University Hospital ; Oslo, Norway ; Biotechnology Center; University of Oslo ; Oslo, Norway ; K.G. Jebsen Inflammation Research Center; University of Oslo ; Oslo, Norway ; K.G. Jebsen Center for Cancer Immunotherapy; University of Oslo ; Oslo, Norway ; Department of Infectious Diseases; Oslo University Hospital ; Oslo, Norway
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Gonzalez JP, Ramachandran J, Xie LH, Contreras JE, Fraidenraich D. Selective Connexin43 Inhibition Prevents Isoproterenol-Induced Arrhythmias and Lethality in Muscular Dystrophy Mice. Sci Rep 2015; 5:13490. [PMID: 26311238 PMCID: PMC4550874 DOI: 10.1038/srep13490] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 07/27/2015] [Indexed: 12/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by an X-linked mutation that leads to the absence of dystrophin, resulting in life-threatening arrhythmogenesis and associated heart failure. We targeted the gap junction protein connexin43 (Cx43) responsible for maintaining cardiac conduction. In mild mdx and severe mdx:utr mouse models of DMD, and human DMD tissues, Cx43 was found to be pathologically mislocalized to lateral sides of cardiomyocytes. In addition, overall Cx43 protein levels were markedly increased in mouse and human DMD heart tissues examined. Electrocardiography on isoproterenol challenged mice showed that both models developed arrhythmias and died within 24 hours, while wild-type mice were free of pathology. Administering peptide mimetics to inhibit lateralized Cx43 function prior to challenge protected mdx mice from arrhythmogenesis and death, while mdx:utr mice displayed markedly improved ECG scores. These findings suggest that Cx43 lateralization contributes significantly to DMD arrhythmogenesis and that selective inhibition may provide substantial benefit.
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Affiliation(s)
- J Patrick Gonzalez
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ USA
| | - Jayalakshmi Ramachandran
- Department of Pharmacology and Physiology, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ USA
| | - Lai-Hua Xie
- Department of Pharmacology and Physiology, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ USA
| | - Jorge E Contreras
- Department of Pharmacology and Physiology, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ USA
| | - Diego Fraidenraich
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ USA
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212
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Tanyeri G, Celik O, Erbas O, Oltulu F, Yilmaz Dilsiz O. The effectiveness of different neuroprotective agents in facial nerve injury: An experimental study. Laryngoscope 2015; 125:E356-64. [DOI: 10.1002/lary.25554] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Gokce Tanyeri
- Department of Otolaryngology-Head & Neck Surgery; Celal Bayar University Faculty of Medicine; Manisa Turkey
| | - Onur Celik
- Department of Otolaryngology-Head & Neck Surgery; Celal Bayar University Faculty of Medicine; Manisa Turkey
| | - Oytun Erbas
- Department of Physiology; Ege University Faculty of Medicine
| | - Fatih Oltulu
- Department of Histology & Embryology; Ege University Faculty of Medicine; Izmir Turkey
| | - Ozlem Yilmaz Dilsiz
- Department of Histology & Embryology; Ege University Faculty of Medicine; Izmir Turkey
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213
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Poyet C, Buser L, Roudnicky F, Detmar M, Hermanns T, Mannhard D, Höhn A, Rüschoff J, Zhong Q, Sulser T, Moch H, Wild PJ. Connexin 43 expression predicts poor progression-free survival in patients with non-muscle invasive urothelial bladder cancer. J Clin Pathol 2015; 68:819-24. [PMID: 26251520 PMCID: PMC4602233 DOI: 10.1136/jclinpath-2015-202898] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/25/2015] [Indexed: 12/05/2022]
Abstract
Objectives To evaluate the protein expression of connexin 43 (Cx43) in primary urothelial bladder cancer and test its association with the histopathological characteristics and clinical outcome. Methods A tissue microarray containing 348 tissue samples from 174 patients with primary urothelial carcinomas of the bladder was immunohistochemically stained for Cx43. The intensity of staining was semiquantitatively evaluated (score 0, 1+, 2+), and the association with clinicopathological features was assessed. Univariable and multivariable analyses were performed to identify predictors for progression-free survival (PFS). Results Membranous Cx43 immunoreactivity was detected in 118 (67.8%) of 174 analysable urothelial carcinomas, of which 31 (17.8%) showed even a strong (score 2+) and mainly homogeneous staining. Strong expression levels of Cx43 (score 2+) were associated with higher tumour grade, multiplicity and increased proliferation (all p<0.05). In the subgroup of patients with stage pTa and pT1 bladder tumours (n=158), strong Cx43 expression (p<0.001), solid growth pattern (p<0.001) and increased Ki-67 proliferation fraction (p<0.05) were significantly associated with shorter PFS in an univariable Cox regression analysis. In multivariable Cox regression models, Cx43 immunoreactivity and histological growth pattern remained highly significant and adverse risk factors for PFS. Conclusions The expression levels of Cx43 are frequent in non-muscle invasive bladder cancer (NMIBC), with high expression levels being associated with poor prognosis. Routine assessment of Cx43 expression may improve the identification of high-risk NMIBC.
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Affiliation(s)
- Cédric Poyet
- Department of Urology, University Hospital Zurich, Zurich, Switzerland
| | - Lorenz Buser
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Filip Roudnicky
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Michael Detmar
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
| | - Thomas Hermanns
- Department of Urology, University Hospital Zurich, Zurich, Switzerland
| | - Doris Mannhard
- Department of Urology, University Hospital Zurich, Zurich, Switzerland
| | - Andrej Höhn
- Department of Urology, University Hospital Zurich, Zurich, Switzerland
| | - Jan Rüschoff
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Qing Zhong
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Tullio Sulser
- Department of Urology, University Hospital Zurich, Zurich, Switzerland
| | - Holger Moch
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Peter J Wild
- Institute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
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214
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Hinkel R, Ball HL, DiMaio JM, Shrivastava S, Thatcher JE, Singh AN, Sun X, Faskerti G, Olson EN, Kupatt C, Bock-Marquette I. C-terminal variable AGES domain of Thymosin β4: the molecule's primary contribution in support of post-ischemic cardiac function and repair. J Mol Cell Cardiol 2015; 87:113-25. [PMID: 26255251 DOI: 10.1016/j.yjmcc.2015.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 06/12/2015] [Accepted: 07/08/2015] [Indexed: 12/19/2022]
Abstract
Repairing defective cardiac cells is important towards improving heart function. Due to the frequency and severity of ischemic heart disease, management of patients featuring this type of cardiac failure receives significant interest. Previously we discovered that Thymosin β4 (TB4), a 43 amino-acid secreted actin sequestering peptide, is beneficial for myocardial cell survival and coronary re-growth after infarction in adult mammals. Considering the regenerative potential of full-length TB4 in the heart, and that minimal structural variations alter TB4's influence on actin assembly and cell movement, we investigated how various TB4 domains affect cardiac cell behavior and post-ischemic mammalian heart function. We synthesized 17 domain combinations of full-length TB4 and analyzed their impact on embryonic cardiac cells in vitro, and after cardiac infarction in vivo. We discovered the domains of TB4 affect cardiac cell behavior distinctly. We revealed TB4 specific C-terminal tetrapeptide, AGES, increases embryonic cardiac cell migration and myocyte beating in culture, and improves adult mammalian heart function following ischemia. Investigating the molecular background and mechanism we discovered systemic injection of AGES enhances early myocyte survival by activating Akt-mediated signaling mechanisms, increases coronary vessel growth and inhibits inflammation in mice and pigs. Biodistribution analyses revealed cardiomyocytes uptake AGES efficiently in vitro and in vivo projecting a potential independent clinical utilization for the tetrapeptide. Our comprehensive domain investigations also suggest, preservation and/or restoration of cardiomyocyte communication is a target of TB4 and AGES, and critical to improve post-ischemic heart function in pigs. In summary, we identified the C-terminal four amino-acid variable end of TB4 as the essential and responsible domain for the molecule's full benefits in the hypoxic heart. Additionally, we introduced AGES as a novel, systemically applicable drug candidate to aid cardiac infarction in adult mammals.
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Affiliation(s)
- Rabea Hinkel
- Internal Medicine I, University Clinic Grosshadern, Munich 81377, Germany
| | - Haydn L Ball
- Protein Chemistry Technology Center University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - J Michael DiMaio
- Department of Cardiovascular and Thoracic Surgery University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Santwana Shrivastava
- Department of Cardiovascular and Thoracic Surgery University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jeffrey E Thatcher
- Department of Cardiovascular and Thoracic Surgery University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ajay N Singh
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiankai Sun
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gabor Faskerti
- University of Pecs, Faculty of Medicine, Szentagothai Research Centre, Pecs 7624, Hungary
| | - Eric N Olson
- Department of Molecular Biology University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christian Kupatt
- Internal Medicine I, University Clinic Grosshadern, Munich 81377, Germany
| | - Ildiko Bock-Marquette
- Department of Cardiovascular and Thoracic Surgery University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; University of Pecs, Faculty of Medicine, Szentagothai Research Centre, Pecs 7624, Hungary.
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215
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Faniku C, Wright CS, Martin PE. Connexins and pannexins in the integumentary system: the skin and appendages. Cell Mol Life Sci 2015; 72:2937-47. [PMID: 26091749 PMCID: PMC11113313 DOI: 10.1007/s00018-015-1969-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
Abstract
The integumentary system comprises the skin and its appendages, which includes hair, nails, feathers, sebaceous and eccrine glands. In this review, we focus on the expression profile of connexins and pannexins throughout the integumentary system in mammals, birds and fish. We provide a picture of the complexity of the connexin/pannexin network illustrating functional importance of these proteins in maintaining the integrity of the epidermal barrier. The differential regulation and expression of connexins and pannexins during skin renewal, together with a number of epidermal, hair and nail abnormalities associated with mutations in connexins, emphasize that the correct balance of connexin and pannexin expression is critical for maintenance of the skin and its appendages with both channel and non-channel functions playing profound roles. Changes in connexin expression during both hair and feather regeneration provide suggestions of specialized communication compartments. Finally, we discuss the potential use of zebrafish as a model for connexin skin biology, where evidence mounts that differential connexin expression is involved in skin patterning and pigmentation.
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Affiliation(s)
- Chrysovalantou Faniku
- Department of Life Sciences and Institute for Applied Health Research, Glasgow Caledonian University, Glasgow, G4 0BA UK
| | - Catherine S. Wright
- Department of Life Sciences and Institute for Applied Health Research, Glasgow Caledonian University, Glasgow, G4 0BA UK
| | - Patricia E. Martin
- Department of Life Sciences and Institute for Applied Health Research, Glasgow Caledonian University, Glasgow, G4 0BA UK
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216
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Localization and quantitative analysis of Cx43 in porcine oocytes during in vitro maturation. ZYGOTE 2015; 24:364-70. [DOI: 10.1017/s0967199415000271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
SummaryMany studies of the main gap junction protein, Cx43, have been conducted in porcine oocyte research, but they have been limited to investigations of cumulus–oocyte complexes (COCs). In this study, we verified Cx43 not in COCs, but in porcine oocytes during maturation, and conducted a quantitative time course analysis. The location and dynamics of Cx43 were examined by immunocytochemistry and western blotting, respectively. COCs were cultured in NCSU23 medium and processed for immunocytochemistry and western blotting at 0, 14, 28, and 42 h after denuding. A Cx43 signal was detected on oolemmas, transzonal projections and the surface of zona pellucidae. Western blotting showed that Cx43 band density increased from 0 to 14 h, and gradually decreased thereafter. Our results clarified that Cx43 is localized in the ooplasmic membrane through zona pellucidae and its level changes over time during culture in porcine oocytes.
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217
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Xie HY, Cui Y, Deng F, Feng JC. Connexin: a potential novel target for protecting the central nervous system? Neural Regen Res 2015; 10:659-66. [PMID: 26170830 PMCID: PMC4424762 DOI: 10.4103/1673-5374.155444] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2014] [Indexed: 01/11/2023] Open
Abstract
Connexin subunits are proteins that form gap junction channels, and play an important role in communication between adjacent cells. This review article discusses the function of connexins/hemichannels/gap junctions under physiological conditions, and summarizes the findings regarding the role of connexins/hemichannels/gap junctions in the physiological and pathological mechanisms underlying central nervous system diseases such as brain ischemia, traumatic brain and spinal cord injury, epilepsy, brain and spinal cord tumor, migraine, neuroautoimmune disease, Alzheimer's disease, Parkinson's disease, X-linked Charcot-Marie-Tooth disease, Pelizaeus-Merzbacher-like disease, spastic paraplegia and maxillofacial dysplasia. Connexins are considered to be a potential novel target for protecting the central nervous system.
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Affiliation(s)
- Hong-Yan Xie
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Yu Cui
- Department of Neurosurgery, the First People's Hospital of Xianyang, Xianyang, Shaanxi Province, China
| | - Fang Deng
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
| | - Jia-Chun Feng
- Departmet of Neurology, the First Hospital of Jilin University, Changchun, Jilin Province, China
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218
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Retamal MA, León-Paravic CG, Ezquer M, Ezquer F, Rio RD, Pupo A, Martínez AD, González C. Carbon monoxide: A new player in the redox regulation of connexin hemichannels. IUBMB Life 2015; 67:428-37. [DOI: 10.1002/iub.1388] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/05/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Carmen G. León-Paravic
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Marcelo Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Fernando Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina; Clínica Alemana Universidad del Desarrollo; Santiago Chile
| | - Rodrigo Del Rio
- Centro de Investigación Biomédica; Universidad Autónoma de Chile; Santiago Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
| | - Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias; Instituto de Neurociencia; Universidad de Valparaíso; Valparaíso Chile
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219
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Sovadinova I, Babica P, Böke H, Kumar E, Wilke A, Park JS, Trosko JE, Upham BL. Phosphatidylcholine Specific PLC-Induced Dysregulation of Gap Junctions, a Robust Cellular Response to Environmental Toxicants, and Prevention by Resveratrol in a Rat Liver Cell Model. PLoS One 2015; 10:e0124454. [PMID: 26023933 PMCID: PMC4449167 DOI: 10.1371/journal.pone.0124454] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 03/10/2015] [Indexed: 12/04/2022] Open
Abstract
Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. In conclusion: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap junction channels are closed by toxicants vary. Thus, accurate assessments of risk posed by toxic agents, and the role of dietary phytochemicals play in preventing or reversing the effects of these agents must take into account the specific mechanisms involved in the cancer process.
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Affiliation(s)
- Iva Sovadinova
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Research Centre for Toxic Compounds in the Environment—RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Pavel Babica
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Department of Experimental Phycology and Ecotoxicology, Institute of Botany ASCR, Lidicka 25/27, CZ60200, Brno, Czech Republic
| | - Hatice Böke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Esha Kumar
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Andrew Wilke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Joon-Suk Park
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - James E. Trosko
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Brad L. Upham
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- * E-mail:
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220
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Martinez JM, Wang HZ, Lin RZ, Brink PR, White TW. Differential regulation of Connexin50 and Connexin46 by PI3K signaling. FEBS Lett 2015; 589:1340-5. [PMID: 25935417 PMCID: PMC4433579 DOI: 10.1016/j.febslet.2015.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/16/2015] [Indexed: 01/28/2023]
Abstract
Gap junction channels can modify their activity in response to cell signaling pathways. Here, we demonstrate that Connexin50 (Cx50) coupling, but not Connexin46 (Cx46), increased when co-expressed with a constitutively active p110α subunit of PI3K in Xenopus oocytes. In addition, inhibition of PI3K signaling by blocking p110α, or Akt, significantly decreased gap junctional conductance in Cx50 transfected HeLa cells, with no effect on Cx46. Alterations in coupling levels were not a result of reduced Cx50 unitary conductance, suggesting that changes in the number of active channels were responsible. These data indicate that Cx50 is specifically regulated by the PI3K signaling pathway.
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Affiliation(s)
- Jennifer M Martinez
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Hong-Zhan Wang
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Thomas W White
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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221
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Jones SA, Lancaster MK. Progressive age-associated activation of JNK associates with conduction disruption in the aged atrium. Mech Ageing Dev 2015; 146-148:72-80. [PMID: 25956603 PMCID: PMC4461009 DOI: 10.1016/j.mad.2015.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 12/19/2022]
Abstract
Guinea pig atria from multiple ages ranging from neonate to old age were compared. Action potential conduction velocity showed a significant reduction in advanced age. Connexin43 protein reduced dramatically in the right atria with increasing age. An age-dependent rise in activated-JNK correlated with a rise in phosphorylated Cx43. JNK signalling is a mediator of gap junctional remodelling with increased age.
Connexin43 (Cx43) is critical for maintaining electrical conduction across atrial muscle. During progressive ageing atrial conduction slows associating with increasing susceptibility to arrhythmias. Changes in Cx43 protein expression, or its phosphorylation status, can instigate changes in the conduction of the cardiac action potential. This study investigated whether increased levels of activated c-jun N-terminal kinase (JNK) is responsible for the decline of Cx43 during ageing. Right atria from guinea pigs aged between 1 day and 38 months of age were examined. The area of the intercalated disc increased with age concurrent with a 75% decline in C43 protein expression. An age-dependent increase in activated-JNK correlated with a rise in phosphorylated Cx43, but also slowing of action potential conduction velocity across the atria from 0.38 ± 0.01 m/s at 1 month of age to 0.30 ± 0.01 m/s at 38 months. The JNK activator anisomycin increased activated JNK in myocytes and reduced Cx43 protein expression simulating ageing. The JNK inhibitor SP600125, was found to eradicate almost all trace of Cx43 protein. We conclude that in vivo activation of JNK increases with age leading to the loss of Cx43 protein resulting in impaired conduction and contributing to the increasing risk of atrial arrhythmias with advancing age.
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Affiliation(s)
- Sandra A Jones
- School of Biological, Biomedical and Environmental Sciences, University of Hull, Kingston-upon-Hull, HU6 7RX, UK.
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Ye XY, Jiang QH, Hong T, Zhang ZY, Yang RJ, Huang JQ, Hu K, Peng YP. Altered expression of connexin43 and phosphorylation connexin43 in glioma tumors. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:4296-4306. [PMID: 26191122 PMCID: PMC4502994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 04/18/2015] [Indexed: 06/04/2023]
Abstract
In this study, we aim to evaluate the connexin (Cx43) and phosphorylation Cx43 (p-Cx43) expression of human glioma tumors and correlate their expression with degrees of malignancy and proliferation, apoptosis, and migration activity of tumors. Cx43 and p-Cx43 expression were examined by Western blot analysis and immunohistochemical staining. The U251 cell viability was measured by MTT analysis. The apoptosis and migration were also evaluated by flow cytometric analysis and fluoroblok transwell chambers, respectively. We found that the Cx43 expression were significantly downregulated in in malignant glioma (WHO grade III and IV), compared to the malignant glioma (WHO grade I and II) and the p-Cx43 expression levels of malignant glioma (WHO grade III and IV) were significantly increased (P<0.05), compared to the malignant glioma (WHO grade I and II) at immunohistochemical analysis. After treatment of cells with a specific inhibitor of PKC, MAPK, and PTK inhibitors, the cell viability and migration were significantly decreased, while the apoptosis was slightly induced. In conclusion, the Cx43 expression level is inversely correlated with the tumor grade and proliferation and migration activity of tumor. Higher p-Cx43 expression level in high tumor grade suggests that a complex mechanism is involved in the suppression of tumor growth by connexins.
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Affiliation(s)
- Xin-Yun Ye
- Department of Neurosurgery, Nanfang Hospital, Southern Medical UniversityGuangzhou 510515, Guangdong, China
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Qiu-Hua Jiang
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Tao Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang UniversityNanchang 330006, Jiangxi, China
| | - Zhen-Yu Zhang
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Rui-Jin Yang
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Jin-Qing Huang
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Kun Hu
- Department of Neurosurgery, Ganzhou People’s HospitalGanzhou 341000, Jiangxi, China
| | - Yu-Ping Peng
- Department of Neurosurgery, Nanfang Hospital, Southern Medical UniversityGuangzhou 510515, Guangdong, China
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Grek CL, Rhett JM, Bruce JS, Abt MA, Ghatnekar GS, Yeh ES. Targeting connexin 43 with α-connexin carboxyl-terminal (ACT1) peptide enhances the activity of the targeted inhibitors, tamoxifen and lapatinib, in breast cancer: clinical implication for ACT1. BMC Cancer 2015; 15:296. [PMID: 25881004 PMCID: PMC4407347 DOI: 10.1186/s12885-015-1229-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/19/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Treatment failure is a critical issue in breast cancer and identifying useful interventions that optimize current cancer therapies remains a critical unmet need. Expression and functional studies have identified connexins (Cxs), a family of gap junction proteins, as potential tumor suppressors. Studies suggest that Cx43 has a role in breast cancer cell proliferation, differentiation, and migration. Although pan-gap junction drugs are available, the lack of specificity of these agents increases the opportunity for off target effects. Consequently, a therapeutic agent that specifically modulates Cx43 would be beneficial and has not been tested in breast cancer. In this study, we now test an agent that specifically targets Cx43, called ACT1, in breast cancer. METHODS We evaluated whether direct modulation of Cx43 using a Cx43-directed therapeutic peptide, called ACT1, enhances Cx43 gap junctional activity in breast cancer cells, impairs breast cancer cell proliferation or survival, and enhances the activity of the targeted inhibitors tamoxifen and lapatinib. RESULTS Our results show that therapeutic modulation of Cx43 by ACT1 maintains Cx43 at gap junction sites between cell-cell membrane borders of breast cancer cells and augments gap junction activity in functional assays. The increase in Cx43 gap junctional activity achieved by ACT1 treatment impairs proliferation or survival of breast cancer cells but ACT1 has no effect on non-transformed MCF10A cells. Furthermore, treating ER+ breast cancer cells with a combination of ACT1 and tamoxifen or HER2+ breast cancer cells with ACT1 and lapatinib augments the activity of these targeted inhibitors. CONCLUSIONS Based on our findings, we conclude that modulation of Cx43 activity in breast cancer can be effectively achieved with the agent ACT1 to sustain Cx43-mediated gap junctional activity resulting in impaired malignant progression and enhanced activity of lapatinib and tamoxifen, implicating ACT1 as part of a combination regimen in breast cancer.
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Affiliation(s)
- Christina L Grek
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, USA.
| | - Joshua Matthew Rhett
- Department of Surgery, Division of General Surgery, Medical University of South Carolina, Charleston, SC, USA.
| | - Jaclynn S Bruce
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
| | - Melissa A Abt
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
| | - Gautam S Ghatnekar
- FirstString Research, Inc., 300 W. Coleman Blvd., Suite 203, Mount Pleasant, SC, USA.
| | - Elizabeth S Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, BSB358, MSC509, Charleston, SC, 29425, USA.
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224
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Rodrigues SF, Granger DN. Blood cells and endothelial barrier function. Tissue Barriers 2015; 3:e978720. [PMID: 25838983 DOI: 10.4161/21688370.2014.978720] [Citation(s) in RCA: 201] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/15/2014] [Indexed: 12/18/2022] Open
Abstract
The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction.
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Key Words
- AJ, Adherens junctions
- ANG-1, Angiopoietin 1
- AQP, Aquaporins
- BBB, blood brain barrier
- CNS, Central nervous system
- COPD, Chronic obstructive pulmonary disease
- EAE, Experimental autoimmune encephalomyelitis
- EPAC1, Exchange protein activated by cyclic AMP
- ERK1/2, Extracellular signal-regulated kinases 1 and 2
- Endothelial barrier
- FA, Focal adhesions
- FAK, focal adhesion tyrosine kinase
- FoxO1, Forkhead box O1
- GAG, Glycosaminoglycans
- GDNF, Glial cell-derived neurotrophic factor
- GJ, Gap junctions
- GPCR, G-protein coupled receptors
- GTPase, Guanosine 5'-triphosphatase
- HMGB-1, High mobility group box 1
- HRAS, Harvey rat sarcoma viral oncogene homolog
- ICAM-1, Intercellular adhesion molecule 1
- IL-1β, Interleukin 1 beta
- IP3, Inositol 1,4,5-triphosphate
- JAM, Junctional adhesion molecules
- MEK, Mitogen-activated protein kinase kinase
- MLC, Myosin light chain
- MLCK, Myosin light-chain kinase
- MMP, Matrix metalloproteinases
- NO, Nitric oxide
- OSM, Oncostatin M
- PAF, Platelet activating factor
- PDE, Phosphodiesterase
- PKA, Protein kinase A
- PNA, Platelet-neutrophil aggregates
- ROS, Reactive oxygen species
- Rac1, Ras-related C3 botulinum toxin substrate 1
- Rap1, Ras-related protein 1
- RhoA, Ras homolog gene family, member A
- S1P, Sphingosine-1-phosphate
- SCID, Severe combined immunodeficient
- SOCS-3, Suppressors of cytokine signaling 3
- Shp-2, Src homology 2 domain-containing phosphatase 2
- Src, Sarcoma family of protein kinases
- TEER, Transendothelial electrical resistance
- TGF-beta1, Transforming growth factor-beta1
- TJ, Tight junctions
- TNF-, Tumor necrosis factor alpha
- VCAM-1, Vascular cell adhesion molecule 1
- VE, Vascular endothelial
- VE-PTP, Vascular endothelial receptor protein tyrosine phosphatase
- VEGF, Vascular endothelial growth factor
- VVO, Vesiculo-vacuolar organelle
- ZO, Zonula occludens
- cAMP, 3'-5'-cyclic adenosine monophosphate
- erythrocytes
- leukocytes
- pSrc, Phosphorylated Src
- platelets
- vascular permeability
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Affiliation(s)
- Stephen F Rodrigues
- Department of Clinical and Toxicological Analyses; School of Pharmaceutical Sciences; University of Sao Paulo ; Sao Paulo, Brazil
| | - D Neil Granger
- Department of Molecular and Cellular Physiology; Louisiana State University Health Sciences Center ; Shreveport, LA USA
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Calder BW, Matthew Rhett J, Bainbridge H, Fann SA, Gourdie RG, Yost MJ. Inhibition of connexin 43 hemichannel-mediated ATP release attenuates early inflammation during the foreign body response. Tissue Eng Part A 2015; 21:1752-62. [PMID: 25760687 DOI: 10.1089/ten.tea.2014.0651] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In the last 50 years, the use of medical implants has increased dramatically. Failure of implanted devices and biomaterials is a significant source of morbidity and increasing healthcare expenditures. An important cause of implant failure is the host inflammatory response. Recent evidence implicates extracellular ATP as an important inflammatory signaling molecule. A major pathway for release of cytoplasmic ATP into the extracellular space is through connexin hemichannels, which are the unpaired constituents of gap junction intercellular channels. Blockade of hemichannels of the connexin 43 (Cx43) isoform has been shown to reduce inflammation and improve healing. We have developed a Cx43 mimetic peptide (JM2) that targets the microtubule-binding domain of Cx43. The following report investigates the role of the Cx43 microtubule-binding domain in extracellular ATP release by Cx43 hemichannels and how this impacts early inflammatory events of the foreign body reaction. METHODS In vitro Cx43 hemichannel-mediated ATP release by cultured human microvascular endothelial cells subjected to hypocalcemic and normocalcemic conditions was measured after application of JM2 and the known hemichannel blocker, flufenamic acid. A submuscular silicone implant model was used to investigate in vivo ATP signaling during the early foreign body response. Implants were coated with control pluronic vehicle or pluronic carrying JM2, ATP, JM2+ATP, or known hemichannel blockers and harvested at 24 h for analysis. RESULTS JM2 significantly inhibited connexin hemichannel-mediated ATP release from cultured endothelial cells. Importantly, the early inflammatory response to submuscular silicone implants was inhibited by JM2. The reduction in inflammation by JM2 was reversed by the addition of exogenous ATP to the pluronic vehicle. CONCLUSIONS These data indicate that ATP released through Cx43 hemichannels into the vasculature is an important signal driving the early inflammatory response to implanted devices. A vital aspect of this work is that it demonstrates that targeted molecular therapeutics, such as JM2, provide the capacity to regulate inflammation in a clinically relevant system.
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Affiliation(s)
- Bennett W Calder
- 1Department of Surgery, Medical University of South Carolina, Charleston, South Carolina
| | - Joshua Matthew Rhett
- 1Department of Surgery, Medical University of South Carolina, Charleston, South Carolina
| | - Heather Bainbridge
- 1Department of Surgery, Medical University of South Carolina, Charleston, South Carolina
| | - Stephen A Fann
- 1Department of Surgery, Medical University of South Carolina, Charleston, South Carolina
| | - Robert G Gourdie
- 2Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion School of Medicine and Research Institute, Roanoke, Virginia
| | - Michael J Yost
- 1Department of Surgery, Medical University of South Carolina, Charleston, South Carolina
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226
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Salas D, Puebla C, Lampe PD, Lavandero S, Sáez JC. Role of Akt and Ca2+ on cell permeabilization via connexin43 hemichannels induced by metabolic inhibition. Biochim Biophys Acta Mol Basis Dis 2015; 1852:1268-77. [PMID: 25779082 DOI: 10.1016/j.bbadis.2015.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/25/2015] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
Abstract
Connexin hemichannels are regulated under physiological and pathological conditions. Metabolic inhibition, a model of ischemia, promotes surface hemichannel activation associated, in part, with increased surface hemichannel levels, but little is known about its underlying mechanism. Here, we investigated the role of Akt on the connexin43 hemichannel's response induced by metabolic inhibition. In HeLa cells stably transfected with rat connexin43 fused to EGFP (HeLa43 cells), metabolic inhibition induced a transient Akt activation necessary to increase the amount of surface connexin43. The increase in levels of surface connexin43 was also found to depend on an intracellular Ca2+ signal increase that was partially mediated by Akt activation. However, the metabolic inhibition-induced Akt activation was not significantly affected by intracellular Ca2+ chelation. The Akt-dependent increase in connexin43 hemichannel activity in HeLa43 cells also occurred after oxygen-glucose deprivation, another ischemia-like condition, and in cultured cortical astrocytes (endogenous connexin43 expression system) under metabolic inhibition. Since opening of hemichannels has been shown to accelerate cell death, inhibition of Akt-dependent phosphorylation of connexin43 hemichannels could reduce cell death induced by ischemia/reperfusion.
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Affiliation(s)
- Daniela Salas
- Advanced Center for Chronic Diseases (ACCDIS) & Centro Estudios Moleculares de la Célula (CMEC), Facultad Ciencias Químicas y Farmacéuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile; Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Carlos Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paul D Lampe
- Translational Research Program, Human Biology and Public Health Sciences Divisions, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDIS) & Centro Estudios Moleculares de la Célula (CMEC), Facultad Ciencias Químicas y Farmacéuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso, Valparaíso, Chile.
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227
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Protection of erythropoietin against ischemic neurovascular unit injuries through the effects of connexin43. Biochem Biophys Res Commun 2015; 458:656-662. [DOI: 10.1016/j.bbrc.2015.02.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 02/04/2015] [Indexed: 11/19/2022]
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228
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Tabernero A, Gangoso E, Jaraíz-Rodríguez M, Medina JM. The role of connexin43-Src interaction in astrocytomas: A molecular puzzle. Neuroscience 2015; 323:183-94. [PMID: 25711938 DOI: 10.1016/j.neuroscience.2015.02.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/10/2015] [Accepted: 02/13/2015] [Indexed: 12/18/2022]
Abstract
Connexin43 (Cx43) as a building block of gap junction channels and hemichannels exerts important functions in astrocytes. When these cells acquire a malignant phenotype Cx43 protein but not mRNA levels are downregulated, being negligible in high-grade astrocytoma or glioblastoma multiforme, the most common and deadliest of malignant primary brain tumors in adults. Some microRNAs associated to glioma target Cx43 and could explain the lack of correlation between mRNA and protein levels of Cx43 found in some high-grade astrocytomas. More importantly, these microRNAs could be a promising therapeutic target. A great number of studies have confirmed the relationship between cancer and connexins that was proposed by Loewenstein more than 40years ago, but these studies have also revealed that this is a very complex relationship. Indeed, restoring Cx43 to glioma cells reduces their rate of proliferation and their tumorigenicity but this tumor suppressor effect could be counterbalanced by its effects on invasiveness, adhesion and migration. The mechanisms underlying these effects suggest the participation of a great variety of proteins that bind to different regions of Cx43. The present review focuses on an intrinsically disordered region of the C-terminal domain of Cx43 in which converges the interaction of several proteins, including the proto-oncogene Src. We summarize data that indicate that Cx43-Src interaction inhibits the oncogenic activity of Src and promotes a conformational change in the structure of Cx43 that allosterically modifies the binding to other important signaling proteins. As a consequence, crucial cell functions, such as proliferation or migration, could be strongly affected. We propose that the knowledge of the structural basis of the antitumorigenic effect of Cx43 on astrocytomas could help to design new therapies against this incurable disease.
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Affiliation(s)
- A Tabernero
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Spain.
| | - E Gangoso
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Spain
| | - M Jaraíz-Rodríguez
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Spain
| | - J M Medina
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Spain
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229
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Stecklum M, Wulf-Goldenberg A, Purfürst B, Siegert A, Keil M, Eckert K, Fichtner I. Cell differentiation mediated by co-culture of human umbilical cord blood stem cells with murine hepatic cells. In Vitro Cell Dev Biol Anim 2015; 51:183-91. [PMID: 25270685 DOI: 10.1007/s11626-014-9817-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 08/28/2014] [Indexed: 12/27/2022]
Abstract
In the present study, purified human cord blood stem cells were co-cultivated with murine hepatic alpha mouse liver 12 (AML12) cells to compare the effect on endodermal stem cell differentiation by either direct cell-cell interaction or by soluble factors in conditioned hepatic cell medium. With that approach, we want to mimic in vitro the situation of preclinical transplantation experiments using human cells in mice. Cord blood stem cells, cultivated with hepatic conditioned medium, showed a low endodermal differentiation but an increased connexin 32 (Cx32) and Cx43, and cytokeratin 8 (CK8) and CK19 expression was monitored by reverse transcription polymerase chain reaction (RT-PCR). Microarray profiling indicated that in cultivated cord blood cells, 604 genes were upregulated 2-fold, with the highest expression for epithelial CK19 and epithelial cadherin (E-cadherin). On ultrastructural level, there were no major changes in the cellular morphology, except a higher presence of phago(ly)some-like structures observed. Direct co-culture of AML12 cells with cord blood cells led to less incisive differentiation with increased sex-determining region Y-box 17 (SOX17), Cx32 and Cx43, as well as epithelial CK8 and CK19 expressions. On ultrastructural level, tight cell contacts along the plasma membranes were revealed. FACS analysis in co-cultivated cells quantified dye exchange on low level, as also proved by time relapse video-imaging of labelled cells. Modulators of gap junction formation influenced dye transfer between the co-cultured cells, whereby retinoic acid increased and 3-heptanol reduced the dye transfer. The study indicated that the cell-co-cultured model of human umbilical cord blood cells and murine AML12 cells may be a suitable approach to study some aspects of endodermal/hepatic cell differentiation induction.
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Affiliation(s)
- Maria Stecklum
- Max Delbrück Center for Molecular Medicine, Berlin-Buch, Robert-Rössle-Str. 10, 13125, Berlin, Germany,
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230
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Connexins and skin disease: insights into the role of beta connexins in skin homeostasis. Cell Tissue Res 2015; 360:645-58. [PMID: 25616557 DOI: 10.1007/s00441-014-2094-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/08/2014] [Indexed: 12/20/2022]
Abstract
Cell-to-cell communication triggered by connexin channels plays a central role in maintaining epidermal homeostasis. Here, we discuss the role of the beta connexin subgroup, where site-specific mutations in at least 4 of these proteins lead to distinctive non-inflammatory and inflammatory hyperproliferative epidermal disorders. Recent advances in the molecular pathways evoked and correlation with clinical outcome are discussed. The latest data provide increasing evidence that connexins in the epidermis are sensors to environmental stress and that targeting aberrant hemichannel activity holds significant therapeutic potential for inflammatory skin disorders.
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231
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Forster T, Rausch V, Zhang Y, Isayev O, Heilmann K, Schoensiegel F, Liu L, Nessling M, Richter K, Labsch S, Nwaeburu CC, Mattern J, Gladkich J, Giese N, Werner J, Schemmer P, Gross W, Gebhard MM, Gerhauser C, Schaefer M, Herr I. Sulforaphane counteracts aggressiveness of pancreatic cancer driven by dysregulated Cx43-mediated gap junctional intercellular communication. Oncotarget 2015; 5:1621-34. [PMID: 24742583 PMCID: PMC4039235 DOI: 10.18632/oncotarget.1764] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The extreme aggressiveness of pancreatic ductal adenocarcinoma (PDA) has been
associated with blocked gap junctional intercellular communication (GJIC) and the
presence of cancer stem cells (CSCs). We examined whether disturbed GJIC is
responsible for a CSC phenotype in established and primary cancer cells and patient
tissue of PDA using interdisciplinary methods based in physiology, cell and molecular
biology, histology and epigenetics. Flux of fluorescent dyes and gemcitabine through
gap junctions (GJs) was intact in less aggressive cells but not in highly malignant
cells with morphological dysfunctional GJs. Among several connexins, only Cx43 was
expressed on the cell surface of less aggressive and GJIC-competent cells, whereas
Cx43 surface expression was absent in highly malignant, E-cadherin-negative and
GJIC-incompetent cells. The levels of total Cx43 protein and Cx43 phosphorylated at
Ser368 and Ser279/282 were high in normal tissue but low to absent in malignant
tissue. si-RNA-mediated inhibition of Cx43 expression in GJIC-competent cells
prevented GJIC and induced colony formation and the expression of stem cell-related
factors. The bioactive substance sulforaphane enhanced Cx43 and E-cadherin levels,
inhibited the CSC markers c-Met and CD133, improved the functional morphology of GJs
and enhanced GJIC. Sulforaphane altered the phosphorylation of several kinases and
their substrates and inhibition of GSK3, JNK and PKC prevented sulforaphane-induced
CX43 expression. The sulforaphane-mediated expression of Cx43 was not correlated with
enhanced Cx43 RNA expression, acetylated histone binding and Cx43 promoter
de-methylation, suggesting that posttranslational phosphorylation is the dominant
regulatory mechanism. Together, the absence of Cx43 prevents GJIC and enhances
aggressiveness, whereas sulforaphane counteracts this process, and our findings
highlight dietary co-treatment as a viable treatment option for PDA.
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Affiliation(s)
- Tobias Forster
- General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
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Tarzemany R, Jiang G, Larjava H, Häkkinen L. Expression and function of connexin 43 in human gingival wound healing and fibroblasts. PLoS One 2015; 10:e0115524. [PMID: 25584940 PMCID: PMC4293150 DOI: 10.1371/journal.pone.0115524] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 11/25/2014] [Indexed: 11/18/2022] Open
Abstract
Connexins (C×s) are a family of transmembrane proteins that form hemichannels and gap junctions (GJs) on the cell membranes, and transfer small signaling molecules between the cytoplasm and extracellular space and between connecting cells, respectively. Among C×s, suppressing C×43 expression or function promotes skin wound closure and granulation tissue formation, and may alleviate scarring, but the mechanisms are not well understood. Oral mucosal gingiva is characterized by faster wound closure and scarless wound healing outcome as compared to skin wounds. Therefore, we hypothesized that C×43 function is down regulated during human gingival wound healing, which in fibroblasts promotes expression of genes conducive for fast and scarless wound healing. Cultured gingival fibroblasts expressed C×43 as their major connexin. Immunostaining of unwounded human gingiva showed that C×43 was abundantly present in the epithelium, and in connective tissue formed large C×43 plaques in fibroblasts. At the early stages of wound healing, C×43 was strongly down regulated in wound epithelial cells and fibroblasts, returning to the level of normal tissue by day 60 post-wounding. Blocking of C×43 function by C×43 mimetic peptide Gap27 suppressed GJ-mediated dye transfer, promoted migration, and caused significant changes in the expression of wound healing-associated genes in gingival fibroblasts. In particular, out of 54 genes analyzed, several MMPs and TGF-β1, involved in regulation of inflammation and extracellular matrix (ECM) turnover, and VEGF-A, involved in angiogenesis, were significantly upregulated while pro-fibrotic ECM molecules, including Collagen type I, and cell contractility-related molecules were significantly down regulated. These responses involved MAPK, GSK3α/β and TGF-β signaling pathways, and AP1 and SP1 transcription factors. Thus, suppressed function of C×43 in fibroblasts promotes their migration, and regulates expression of wound healing-associated genes via AP1, SP1, MAPK, GSK3α/β and TGF-β signaling pathways, and may promote fast and scarless wound healing in human gingiva.
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Affiliation(s)
- Rana Tarzemany
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Guoqiao Jiang
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Hannu Larjava
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
| | - Lari Häkkinen
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
- * E-mail:
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233
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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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234
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Ampey BC, Morschauser TJ, Lampe PD, Magness RR. Gap junction regulation of vascular tone: implications of modulatory intercellular communication during gestation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 814:117-32. [PMID: 25015806 DOI: 10.1007/978-1-4939-1031-1_11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the vasculature, gap junctions (GJ) play a multifaceted role by serving as direct conduits for cell-cell intercellular communication via the facilitated diffusion of signaling molecules. GJs are essential for the control of gene expression and coordinated vascular development in addition to vascular function. The coupling of endothelial cells to each other, as well as with vascular smooth muscle cells via GJs, plays a relevant role in the control of vasomotor tone, tissue perfusion and arterial blood pressure. The regulation of cell-signaling is paramount to cardiovascular adaptations of pregnancy. Pregnancy requires highly developed cell-to-cell coupling, which is affected partly through the formation of intercellular GJs by Cx43, a gap junction protein, within adjacent cell membranes to help facilitate the increase of uterine blood flow (UBF) in order to ensure adequate perfusion for nutrient and oxygen delivery to the placenta and thus the fetus. One mode of communication that plays a critical role in regulating Cx43 is the release of endothelial-derived vasodilators such as prostacyclin (PGI2) and nitric oxide (NO) and their respective signaling mechanisms involving second messengers (cAMP and cGMP, respectively) that are likely to be important in maintaining UBF. Therefore, the assertion we present in this review is that GJs play an integral if not a central role in maintaining UBF by controlling rises in vasodilators (PGI2 and NO) via cyclic nucleotides. In this review, we discuss: (1) GJ structure and regulation; (2) second messenger regulation of GJ phosphorylation and formation; (3) pregnancy-induced changes in cell-signaling; and (4) the role of uterine arterial endothelial GJs during gestation. These topics integrate the current knowledge of this scientific field with interpretations and hypotheses regarding the vascular effects that are mediated by GJs and their relationship with vasodilatory vascular adaptations required for modulating the dramatic physiological rises in uteroplacental perfusion and blood flow observed during normal pregnancy.
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Affiliation(s)
- Bryan C Ampey
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, School Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, 53715, USA
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Li Y, Han F, Shi Y. Changes in integrin αv, vinculin and connexin43 in the medial prefrontal cortex in rats under single-prolonged stress. Mol Med Rep 2014; 11:2520-6. [PMID: 25483027 PMCID: PMC4337628 DOI: 10.3892/mmr.2014.3030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 10/24/2014] [Indexed: 11/06/2022] Open
Abstract
Post‑traumatic stress disorder (PTSD) is a stress‑accociated mental disorder that occurs as a result of exposure to a traumatic event, with characteristic symptoms, including intrusive memories, hyperarousal and avoidance. The medial prefrontal cortex (mPFC) is known to be significantly involved in emotional adjustment, particularly introspection, inhibition of the amygdala and emotional memory. Previous structural neuroimaging studies have revealed that the mPFC of PTSD patients was significantly smaller when compared with that of controls and their emotional adjustment function was weakened. However, the mechanisms that cause such atrophy remain to be elucidated. The aim of the present study was to elucidate the possible mechanisms involved in apoptosis induced by single‑prolonged stress (SPS) in the mPFC of PTSD rats. SPS is an animal model reflective of PTSD. Of the proposed animal models of PTSD, SPS is one that has been shown to be reliably reproducible in patients with PTSD. Wistar rats were sacrificed at 1, 4, 7 and 14 days after exposure to SPS. Apoptotic cells were assessed using electron microscopy and the TUNEL method. Expression of integrin αv, vinculin and connexin43 were detected using immunohistochemistry, western blotting and reverse transcription polymerase chain reaction. The present results demonstrated that apoptotic cells significantly increased in the mPFC of SPS rats, accompanied with changes in expression of integrin αv, vinculin and connexin43. The present results indicated that SPS‑induced apoptosis in the mPFC of PTSD rats and the mitochondrial pathway were involved in the process of SPS‑induced apoptosis.
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Affiliation(s)
- Yana Li
- Department of Histology and Embryology, Institute of Pathology and Pathophysiology, Basic Medical Sciences College, China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Fang Han
- Department of Histology and Embryology, Institute of Pathology and Pathophysiology, Basic Medical Sciences College, China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yuxiu Shi
- Department of Histology and Embryology, Institute of Pathology and Pathophysiology, Basic Medical Sciences College, China Medical University, Shenyang, Liaoning 110001, P.R. China
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Hernández-Juárez AA, Lugo-Trampe JDJ, Campos-Acevedo LD, Lugo-Trampe A, Treviño-González JL, de-la-Cruz-Ávila I, Martínez-de-Villarreal LE. GJB2 and GJB6 mutations are an infrequent cause of autosomal-recessive nonsyndromic hearing loss in residents of Mexico. Int J Pediatr Otorhinolaryngol 2014; 78:2107-12. [PMID: 25288386 DOI: 10.1016/j.ijporl.2014.09.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Mutations in the DFNB1 locus are the most common cause of autosomal-recessive nonsyndromic hearing loss (ARNSHL) worldwide. The aim of this study was to identify the most frequent mutations in patients with ARNSHL who reside in Northeastern Mexico. METHODS We determined the nucleotide sequence the coding region of GJB2 of 78 patients with ARNSHL. Polymerase chain reaction assays were used to detect the GJB2 IVS1+1G>A mutation and deletions within GJB6. RESULTS GJB2 mutations were detected in 9.6% of the alleles, and c.35delG was the most frequent. Six other less-frequent mutations were detected, including an extremely rare variant (c.645_648delTAGA), a novel mutation (c.35G>A), and one of possible Mexican origin (c.34G>T). GJB6 deletions and GJB2 IVS1+1G>A were not detected. CONCLUSIONS These data suggest that mutations in the DFNB1 locus are a rare cause of ARNSHL among the population of Northeastern Mexico. This confirms the genetic heterogeneity of this condition and indicates that further research is required to determine the other mechanisms of pathogenesis of ARNSHL in Mexicans.
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Affiliation(s)
- Aideé Alejandra Hernández-Juárez
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - José de Jesús Lugo-Trampe
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Luis Daniel Campos-Acevedo
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Angel Lugo-Trampe
- Centro Mesoamericano de Estudios en Salud Pública y Desastres, Universidad Autónoma de Chiapas (UNACH), Carretera Antiguo Aeropuerto; Pista Principal cruce con Pista Secundaria S/N, Col. Solidaridad 2000, CP 30798, Tapachula, Chis, México
| | - José Luis Treviño-González
- Departamento de Otorrinolaringología, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Israel de-la-Cruz-Ávila
- Servicio de Audiología Pediátrica, Hospital Materno-Infantil, Aldama 460, Col. San Rafael, CP. 67190, Guadalupe, N.L., México
| | - Laura Elia Martínez-de-Villarreal
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México.
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Xie F, Yi SL, Hao L, Zhang Y, Zhong JQ. Role of group I metabotropic glutamate receptors, mGluR1/mGluR5, in connexin43 phosphorylation and inhibition of gap junctional intercellular communication in H9c2 cardiomyoblast cells. Mol Cell Biochem 2014; 400:213-22. [DOI: 10.1007/s11010-014-2278-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 11/15/2014] [Indexed: 12/11/2022]
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238
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Patel DM, Dubash AD, Kreitzer G, Green KJ. Disease mutations in desmoplakin inhibit Cx43 membrane targeting mediated by desmoplakin-EB1 interactions. ACTA ACUST UNITED AC 2014; 206:779-97. [PMID: 25225338 PMCID: PMC4164953 DOI: 10.1083/jcb.201312110] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mechanisms by which microtubule plus ends interact with regions of cell-cell contact during tissue development and morphogenesis are not fully understood. We characterize a previously unreported interaction between the microtubule binding protein end-binding 1 (EB1) and the desmosomal protein desmoplakin (DP), and demonstrate that DP-EB1 interactions enable DP to modify microtubule organization and dynamics near sites of cell-cell contact. EB1 interacts with a region of the DP N terminus containing a hotspot for pathogenic mutations associated with arrhythmogenic cardiomyopathy (AC). We show that a subset of AC mutations, in addition to a mutation associated with skin fragility/woolly hair syndrome, impair gap junction localization and function by misregulating DP-EB1 interactions and altering microtubule dynamics. This work identifies a novel function for a desmosomal protein in regulating microtubules that affect membrane targeting of gap junction components, and elucidates a mechanism by which DP mutations may contribute to the development of cardiac and cutaneous diseases.
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Affiliation(s)
- Dipal M Patel
- Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Adi D Dubash
- Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Geri Kreitzer
- Department of Cell and Developmental Biology, Weill Cornell Medical College of Cornell University, New York, NY 10065
| | - Kathleen J Green
- Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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239
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Kelly JJ, Simek J, Laird DW. Mechanisms linking connexin mutations to human diseases. Cell Tissue Res 2014; 360:701-21. [DOI: 10.1007/s00441-014-2024-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/26/2014] [Indexed: 11/30/2022]
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240
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Seki A, Nishii K, Hagiwara N. Gap junctional regulation of pressure, fluid force, and electrical fields in the epigenetics of cardiac morphogenesis and remodeling. Life Sci 2014; 129:27-34. [PMID: 25447447 DOI: 10.1016/j.lfs.2014.10.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/16/2014] [Accepted: 10/29/2014] [Indexed: 01/25/2023]
Abstract
Epigenetic factors of pressure load, fluid force, and electrical fields that occur during cardiac contraction affect cardiac development, morphology, function, and pathogenesis. These factors are orchestrated by intercellular communication mediated by gap junctions, which synchronize action potentials and second messengers. Misregulation of the gap junction protein connexin (Cx) alters cardiogenesis, and can be a pathogenic factor causing cardiac conduction disturbance, fatal arrhythmia, and cardiac remodeling in disease states such as hypertension and ischemia. Changes in Cx expression can occur even when the DNA sequence of the Cx gene itself is unaltered. Posttranslational modifications might reduce arrhythmogenic substrates, improve cardiac function, and promote remodeling in a diseased heart. In this review, we discuss the epigenetic features of gap junctions that regulate cardiac morphology and remodeling. We further discuss potential clinical applications of current knowledge of the structure and function of gap junctions.
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Affiliation(s)
- Akiko Seki
- Department of Cardiology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan; Support Center for Women Health Care Professionals and Researchers, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
| | - Kiyomasa Nishii
- Department of Anatomy and Neurobiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Nobuhisa Hagiwara
- Department of Cardiology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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241
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Li G, Liu X, Liu Z, Su Z. Interactions of connexin 43 and aquaporin-4 in the formation of glioma-induced brain edema. Mol Med Rep 2014; 11:1188-94. [PMID: 25373717 DOI: 10.3892/mmr.2014.2867] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 09/18/2014] [Indexed: 11/05/2022] Open
Abstract
Connexin 43 (Cx43) and aquaporin-4 (AQP4) have important roles in the formation of glioma-induced brain edema; however, the association between these two factors in the development of edema has remained to be elucidated. In the present study, immunofluorescence and western blot analysis revealed that in a rat model of intracranial C6 glioma, Cx43 expression levels were low to undetectable and AQP4 expression levels were low in glioma cells. Significantly higher Cx43 and AQP4 levels were detected in the tissue surrounding the glioma. To further investigate the potential interaction between Cx43 and AQP4, normal glial cells and C6 glioma cells were cultured in hypotonic medium. Reverse transcription quantitative polymerase chain reaction indicated that AQP4 and Cx43 mRNA expression levels increased as a function of time in normal glial cells and C6 glioma cells in a hypotonic environment. However, the increase observed in normal glial cells was significantly lower than that observed in C6 glioma cells. Furthermore, AQP4 expression levels changed prior to alterations in Cx43 expression. Following AQP4 silencing in C6 cells, the increase in Cx43 expression was significantly attenuated (P<0.05). In normal cells, Cx43 silencing did not influence AQP4 expression (P>0.05). Therefore, it was hypothesized that AQP4 and Cx43 had two distinct mechanisms underlying brain edema formation within and surrounding the glioma. Cx43 may be a downstream effector of AQP4. The elucidation of this pathway may aid in the development of drugs targeting the interaction between AQP4 and Cx43, providing novel therapeutic possibilities for glioma-induced brain edema.
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Affiliation(s)
- Gang Li
- Department of Neurosurgery, Tianjin 5th Center Hospital, Tianjin 300450, P.R. China
| | - Xiaozhi Liu
- Department of Neurosurgery, Tianjin 5th Center Hospital, Tianjin 300450, P.R. China
| | - Zhenlin Liu
- Department of Neurosurgery, Tianjin 5th Center Hospital, Tianjin 300450, P.R. China
| | - Zhiguo Su
- Department of Neurosurgery, Tianjin 5th Center Hospital, Tianjin 300450, P.R. China
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Gevaert T, Vanstreels E, Daelemans D, Franken J, Van Der Aa F, Roskams T, De Ridder D. Identification of Different Phenotypes of Interstitial Cells in the Upper and Deep Lamina Propria of the Human Bladder Dome. J Urol 2014; 192:1555-63. [DOI: 10.1016/j.juro.2014.05.096] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2014] [Indexed: 01/14/2023]
Affiliation(s)
- Thomas Gevaert
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
- Translational Cell and Tissue Research, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
- Department of Pathology, AZ Klina, Brasschaat, Belgium
| | - Els Vanstreels
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Dirk Daelemans
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Jan Franken
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Frank Van Der Aa
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Tania Roskams
- Translational Cell and Tissue Research, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Dirk De Ridder
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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243
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Siragam V, Cui X, Masse S, Ackerley C, Aafaqi S, Strandberg L, Tropak M, Fridman MD, Nanthakumar K, Liu J, Sun Y, Su B, Wang C, Liu X, Yan Y, Mendlowitz A, Hamilton RM. TMEM43 mutation p.S358L alters intercalated disc protein expression and reduces conduction velocity in arrhythmogenic right ventricular cardiomyopathy. PLoS One 2014; 9:e109128. [PMID: 25343256 PMCID: PMC4208740 DOI: 10.1371/journal.pone.0109128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/08/2014] [Indexed: 01/04/2023] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease characterized by fibro-fatty replacement of myocardium in the right ventricular free wall and frequently results in life-threatening ventricular arrhythmias and sudden cardiac death. A heterozygous missense mutation in the transmembrane protein 43 (TMEM43) gene, p.S358L, has been genetically identified to cause autosomal dominant ARVC type 5 in a founder population from the island of Newfoundland, Canada. Little is known about the function of the TMEM43 protein or how it leads to the pathogenesis of ARVC. We sought to determine the distribution of TMEM43 and the effect of the p.S358L mutation on the expression and distribution of various intercalated (IC) disc proteins as well as functional effects on IC disc gap junction dye transfer and conduction velocity in cell culture. Through Western blot analysis, transmission electron microscopy (TEM), immunofluorescence (IF), and electrophysiological analysis, our results showed that the stable expression of p.S358L mutation in the HL-1 cardiac cell line resulted in decreased Zonula Occludens (ZO-1) expression and the loss of ZO-1 localization to cell-cell junctions. Junctional Plakoglobin (JUP) and α-catenin proteins were redistributed to the cytoplasm with decreased localization to cell-cell junctions. Connexin-43 (Cx43) phosphorylation was altered, and there was reduced gap junction dye transfer and conduction velocity in mutant TMEM43-transfected cells. These observations suggest that expression of the p.S358L mutant of TMEM43 found in ARVC type 5 may affect localization of proteins involved in conduction, alter gap junction function and reduce conduction velocity in cardiac tissue.
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Affiliation(s)
- Vinayakumar Siragam
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Xuezhi Cui
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Stephane Masse
- Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Cameron Ackerley
- Division of Pathology, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Shabana Aafaqi
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Linn Strandberg
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Michael Tropak
- Genetics and Genome Biology, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Michael D. Fridman
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | | | - Jun Liu
- Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Yu Sun
- Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Bin Su
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Caroline Wang
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Xiaoru Liu
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Yuqing Yan
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Ariel Mendlowitz
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Robert M. Hamilton
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
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Abstract
As noted in the separate introduction to this special topic section, episodic and electrical disorders can appear quite different clinically and yet share many overlapping features, including attack precipitants, therapeutic responses, natural history, and the types of genes that cause many of the genetic forms (i.e., ion channel genes). Thus, as we mapped and attempted to clone genes causing other episodic disorders, ion channels were always outstanding candidates when they mapped to the critical region of linkage in such a family. However, some of these disorders do not result from mutations in channels. This realization has opened up large and exciting new areas for the pathogenesis of these disorders. In some cases, the mutations occur in genes of unknown function or without understanding of molecular pathogenesis. Recently, emerging insights into a fascinating group of episodic movement disorders, the paroxysmal dyskinesias, and study of the causative genes and proteins are leading to the emerging concept of episodic electric disorders resulting from synaptic dysfunction. Much work remains to be done, but the field is evolving rapidly. As it does, we have come to realize that the molecular pathogenesis of electrical and episodic disorders is more complex than a scenario in which such disorders are simply due to mutations in the primary determinants of membrane excitability (channels).
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245
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Zhang Z, Huang Y, Xie H, Pan J, Liu F, Li X, Chen W, Hu J, Liu Z. Benzalkonium chloride suppresses rabbit corneal endothelium intercellular gap junction communication. PLoS One 2014; 9:e109708. [PMID: 25299343 PMCID: PMC4192355 DOI: 10.1371/journal.pone.0109708] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 09/12/2014] [Indexed: 01/12/2023] Open
Abstract
Purpose Gap junction intercellular communication (GJIC) plays a critical role in the maintenance of corneal endothelium homeostasis. We determined if benzalkonium chloride (BAK) alters GJIC activity in the rabbit corneal endothelium since it is commonly used as a drug preservative in ocular eyedrop preparations even though it can have cytotoxic effects. Methods Thirty-six adult New Zealand albino rabbits were randomly divided into three groups. BAK at 0.01%, 0.05%, and 0.1% was applied twice daily to one eye of each of the rabbits in one of the three groups for seven days. The contralateral untreated eyes were used as controls. Corneal endothelial morphological features were observed by in vivo confocal microscopy (IVCM). Immunofluorescent staining resolved changes in gap junction integrity and localization. Western blot analysis and RT-PCR evaluated changes in levels of connexin43 (Cx43) and tight junction zonula occludens-1 (ZO-1) gene and protein expression, respectively. Cx43 and ZO-1 physical interaction was detected by immunoprecipitation (IP). Primary rabbit corneal endothelial cells were cultured in Dulbecco's Modified Eagle Medium (DMEM) containing BAK for 24 hours. The scrape-loading dye transfer technique (SLDT) was used to assess GJIC activity. Results Topical administration of BAK (0.05%, 0.1%) dose dependently disrupted corneal endothelial cell morphology, altered Cx43 and ZO-1 distribution and reduced Cx43 expression. BAK also markedly induced increases in Cx43 phosphorylation status concomitant with decreases in the Cx43-ZO-1 protein-protein interaction. These changes were associated with marked declines in GJIC activity. Conclusions The dose dependent declines in rabbit corneal endothelial GJIC activity induced by BAK are associated with less Cx43-ZO-1 interaction possibly arising from increases in Cx43 phosphorylation and declines in its protein expression. These novel changes provide additional evidence that BAK containing eyedrop preparations should be used with caution to avoid declines in corneal transparency resulting from losses in GJIC activity and endothelial function.
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Affiliation(s)
- Zhenhao Zhang
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Yue Huang
- Institute of Stem Cell and Regenerative Medicine, Medical College, Xiamen University, Xiamen, Fujian, China
| | - Hui Xie
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Juxin Pan
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Fanfei Liu
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Xuezhi Li
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Wensheng Chen
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
| | - Jiaoyue Hu
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
- * E-mail: (ZL); (JH)
| | - Zuguo Liu
- Eye Institute and affiliated Xiamen Eye Center of Xiamen University; Fujian Provincial Key Laboratory of Ophthalmology and Vision Science, Xiamen, Fujian, China
- * E-mail: (ZL); (JH)
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D'hondt C, Iyyathurai J, Himpens B, Leybaert L, Bultynck G. Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond. Front Physiol 2014; 5:348. [PMID: 25309448 PMCID: PMC4162354 DOI: 10.3389/fphys.2014.00348] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/25/2014] [Indexed: 12/13/2022] Open
Abstract
Intercellular communication in primary bovine corneal endothelial cells (BCECs) is mainly driven by the release of extracellular ATP through Cx43 hemichannels. Studying the characteristics of Ca2+-wave propagation in BCECs, an important form of intercellular communication, in response to physiological signaling events has led to the discovery of important insights in the functional properties and regulation of native Cx43 hemichannels. Together with ectopic expression models for Cx43 hemichannels and truncated/mutated Cx43 versions, it became very clear that loop/tail interactions play a key role in controlling the activity of Cx43 hemichannels. Interestingly, the negative regulation of Cx43 hemichannels by enhanced actin/myosin contractility seems to impinge upon loss of these loop/tail interactions essential for opening Cx43 hemichannels. Finally, these molecular insights have spurred the development of novel peptide tools that can selectively inhibit Cx43 hemichannels, but neither Cx43 gap junctions nor hemichannels formed by other Cx isoforms. These tools now set the stage to hunt for novel physiological functions for Cx43 hemichannels in primary cells and tissues and to tackle disease conditions associated with excessive, pathological Cx43-hemichannel openings.
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Affiliation(s)
- Catheleyne D'hondt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Jegan Iyyathurai
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Bernard Himpens
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University Ghent, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
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Takeuchi H, Suzumura A. Gap junctions and hemichannels composed of connexins: potential therapeutic targets for neurodegenerative diseases. Front Cell Neurosci 2014; 8:189. [PMID: 25228858 PMCID: PMC4151093 DOI: 10.3389/fncel.2014.00189] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/19/2014] [Indexed: 12/03/2022] Open
Abstract
Microglia are macrophage-like resident immune cells that contribute to the maintenance of homeostasis in the central nervous system (CNS). Abnormal activation of microglia can cause damage in the CNS, and accumulation of activated microglia is a characteristic pathological observation in neurologic conditions such as trauma, stroke, inflammation, epilepsy, and neurodegenerative diseases. Activated microglia secrete high levels of glutamate, which damages CNS cells and has been implicated as a major cause of neurodegeneration in these conditions. Glutamate-receptor blockers and microglia inhibitors (e.g., minocycline) have been examined as therapeutic candidates for several neurodegenerative diseases; however, these compounds exerted little therapeutic benefit because they either perturbed physiological glutamate signals or suppressed the actions of protective microglia. The ideal therapeutic approach would hamper the deleterious roles of activated microglia without diminishing their protective effects. We recently found that abnormally activated microglia secrete glutamate via gap-junction hemichannels on the cell surface. Moreover, administration of gap-junction inhibitors significantly suppressed excessive microglial glutamate release and improved disease symptoms in animal models of neurologic conditions such as stroke, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. Recent evidence also suggests that neuronal and glial communication via gap junctions amplifies neuroinflammation and neurodegeneration. Elucidation of the precise pathologic roles of gap junctions and hemichannels may lead to a novel therapeutic strategies that can slow and halt the progression of neurodegenerative diseases.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
| | - Akio Suzumura
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
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Brandenburger T, Huhn R, Galas A, Pannen BH, Keitel V, Barthel F, Bauer I, Heinen A. Remote ischemic preconditioning preserves Connexin 43 phosphorylation in the rat heart in vivo. J Transl Med 2014; 12:228. [PMID: 25159820 PMCID: PMC4256705 DOI: 10.1186/s12967-014-0228-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/11/2014] [Indexed: 11/21/2022] Open
Abstract
Background Remote ischemic preconditioning (RIPC) protects the heart from ischemia and reperfusion (I/R) injury. The underlying molecular mechanisms are unclear. It has been demonstrated that Connexin 43 (Cx43) is critically involved in cardioprotective interventions including classical ischemic preconditioning. In the present study we investigated the influence of RIPC on the expression patterns of Cx43 after I/R in the rat heart in vivo. Methods Male Wistar rats were subjected to 35 min regional myocardial ischemia followed by 2 h reperfusion with or without 4 cycles of 5 minutes bilateral hind limb ischemia and reperfusion (RIPC), to RIPC without ischemia or underwent no intervention (Sham). Infarct size was measured by TTC staining. The myocardium was divided into area at risk (AAR) and area not at risk (non AAR). Expression of Cx43-mRNA and protein was analyzed by qPCR and Western Blot analysis, respectively. Localization of Cx43 was visualized by confocal immunofluorescence staining. Results RIPC reduced the infarct size (I/R: 73 ± 5% vs. RIPC I/R: 34 ± 14%, p < 0.05). Expression of Cx43 mRNA did not differ between groups. I/R caused a strong decrease of relative Cx43 protein expression in the AAR that was partly abolished by RIPC. Furthermore, RIPC decreased the level of ischemia-induced dephosphorylation of Cx43. Confocal immunofluorescence staining showed that I/R caused a loss of the Cx43 signal at the intercalated discs, while the Cx43 signal at the intercalated discs was partly sustained after RIPC. Conclusion Preservation of Cx43 protein expression and phosphorylation after RIPC might protect the rat heart in vivo. Electronic supplementary material The online version of this article (doi:10.1186/s12967-014-0228-8) contains supplementary material, which is available to authorized users.
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Pidoux G, Gerbaud P, Dompierre J, Lygren B, Solstad T, Evain-Brion D, Taskén K. A PKA-ezrin-Cx43 signaling complex controls gap junction communication and thereby trophoblast cell fusion. J Cell Sci 2014; 127:4172-85. [PMID: 25052094 DOI: 10.1242/jcs.149609] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cell fusion occurs as part of the differentiation of some cell types, including myotubes in muscle and osteoclasts in remodeling bone. In the human placenta, mononuclear cytotrophoblasts in a human chorionic gonadotropin (hCG)-driven process fuse to form multinucleated syncytia that allow the exchange of nutrients and gases between the maternal and fetal circulation. Experiments in which protein kinase A (PKA) is displaced from A-kinase anchoring proteins (AKAPs), or in which specific AKAPs are depleted by siRNA-mediated knockdown, point to ezrin as a scaffold required for hCG-, cAMP- and PKA-mediated regulation of the fusion process. By a variety of immunoprecipitation and immunolocalization experiments, we show that ezrin directs PKA to a molecular complex of connexin 43 (Cx43, also known as GJA1) and zona occludens-1 (ZO-1, also known as TJP1). A combination of knockdown experiments and reconstitution with ezrin or Cx43 with or without the ability to bind to its interaction partner or to PKA demonstrate that ezrin-mediated coordination of the localization of PKA and Cx43 is necessary for discrete control of Cx43 phosphorylation and hCG-stimulated gap junction communication that triggers cell fusion in cytotrophoblasts.
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Affiliation(s)
- Guillaume Pidoux
- INSERM, U767, Paris, F-75006 France Université Paris Descartes, Paris F-75006, France PremUp, Paris, F-75006 France Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Oslo N-0318, Norway Biotechnology Centre, University of Oslo, Oslo N-0317, Norway
| | - Pascale Gerbaud
- INSERM, U767, Paris, F-75006 France Université Paris Descartes, Paris F-75006, France
| | - Jim Dompierre
- CNRS, FRC3115, Centre de Recherche de Gif, IMAGIF, Plateforme de Microscopie Photonique, Gif-sur-Yvette, F-91198, France
| | - Birgitte Lygren
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Oslo N-0318, Norway Biotechnology Centre, University of Oslo, Oslo N-0317, Norway
| | - Therese Solstad
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Oslo N-0318, Norway Biotechnology Centre, University of Oslo, Oslo N-0317, Norway
| | - Danièle Evain-Brion
- INSERM, U767, Paris, F-75006 France Université Paris Descartes, Paris F-75006, France PremUp, Paris, F-75006 France
| | - Kjetil Taskén
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Oslo N-0318, Norway Biotechnology Centre, University of Oslo, Oslo N-0317, Norway K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo N-0317, Norway K.G. Jebsen Centre for Cancer Immunotherapy, University of Oslo, Oslo N-0317, Norway Department of Infectious Diseases, Oslo University Hospital, N-0407 Oslo, Norway
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Carette D, Gilleron J, Chevallier D, Segretain D, Pointis G. Connexin a check-point component of cell apoptosis in normal and physiopathological conditions. Biochimie 2014; 101:1-9. [DOI: 10.1016/j.biochi.2013.11.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 11/18/2013] [Indexed: 12/16/2022]
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