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Xu Y, Hu J, Yilmaz DE, Bachmann S. Connexin43 is differentially distributed within renal vasculature and mediates profibrotic differentiation in medullary fibroblasts. Am J Physiol Renal Physiol 2021; 320:F17-F30. [PMID: 33196322 DOI: 10.1152/ajprenal.00453.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/16/2020] [Accepted: 11/03/2020] [Indexed: 11/22/2022] Open
Abstract
Connexins (Cxs) form gap junctions for intercellular exchange of inorganic ions and messenger molecules. In the kidney, Cxs play essential roles within its compartments, but data on the precise cellular localization and cell type-related function of their isoforms are scarce. We tested whether Cx43 distribution is restricted to vascular and interstitial cells and whether medullary fibroblasts express Cx43 to coordinate profibrotic signaling. Confocal immunofluorescence techniques, ultrastructural labeling, and functional experiments in cell culture were performed. Cx43 was chiefly expressed in the vasculature but was absent from tubular epithelia. All arterial, arteriolar, and lymphatic endothelia showed continuous Cx43 signal along their borders. In the inner medulla, only the interstitium showed Cx43 signals, which were assigned to fibroblasts and their processes. Cultured Cx43-expressing medullary fibroblasts served to study the role of gap junctions in a profibrotic context. In a dye spreading assay, Cx43-sensitive diffusion of Lucifer yellow was dependent on gap junctional passage. The addition of transforming growth factor-β1 (5 ng/mL for 48 h) activated Cx43 biosynthesis and caused Cx43-sensitive transformation of the fibroblasts into a myofibroblast phenotype. This suggested that Cx43 gap junctional channels enable the coordination of profibrotic signaling between cells of the medullary interstitium. In summary, we demonstrate the presence of Cx43-expressing gap junctions within the two major renal compartments, the vasculature and interstitium. Endothelial Cx43 likely provides functions of an earlier-defined "electrical syncytium" within the vascular wall. Additionally, Cx43 facilitates profibrotic signaling between medullary interstitial fibroblasts.
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Affiliation(s)
- Yan Xu
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Junda Hu
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Duygu Elif Yilmaz
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
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2
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Kosovic I, Filipovic N, Benzon B, Bocina I, Glavina Durdov M, Vukojevic K, Saraga M, Saraga-Babic M. Connexin Signaling in the Juxtaglomerular Apparatus (JGA) of Developing, Postnatal Healthy and Nephrotic Human Kidneys. Int J Mol Sci 2020; 21:E8349. [PMID: 33172216 PMCID: PMC7664435 DOI: 10.3390/ijms21218349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/31/2022] Open
Abstract
Our study analyzed the expression pattern of different connexins (Cxs) and renin positive cells in the juxtaglomerular apparatus (JGA) of developing, postnatal healthy human kidneys and in nephrotic syndrome of the Finnish type (CNF), by using double immunofluorescence, electron microscopy and statistical measuring. The JGA contained several cell types connected by Cxs, and consisting of macula densa, extraglomerular mesangium (EM) and juxtaglomerular cells (JC), which release renin involved in renin-angiotensin- aldosteron system (RAS) of arterial blood pressure control. During JGA development, strong Cx40 expression gradually decreased, while expression of Cx37, Cx43 and Cx45 increased, postnatally showing more equalized expression patterning. In parallel, initially dispersed renin cells localized to JGA, and greatly increased expression in postnatal kidneys. In CNF kidneys, increased levels of Cx43, Cx37 and Cx45 co-localized with accumulations of renin cells in JGA. Additionally, they reappeared in extraglomerular mesangial cells, indicating association between return to embryonic Cxs patterning and pathologically changed kidney tissue. Based on the described Cxs and renin expression patterning, we suggest involvement of Cx40 primarily in the formation of JGA in developing kidneys, while Cx37, Cx43 and Cx45 might participate in JGA signal transfer important for postnatal maintenance of kidney function and blood pressure control.
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Affiliation(s)
- Ivona Kosovic
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, 21000 Split, Croatia; (I.K.); (N.F.); (B.B.); (K.V.)
| | - Natalija Filipovic
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, 21000 Split, Croatia; (I.K.); (N.F.); (B.B.); (K.V.)
| | - Benjamin Benzon
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, 21000 Split, Croatia; (I.K.); (N.F.); (B.B.); (K.V.)
| | - Ivana Bocina
- Department of Biology, Faculty of Science, University of Split, 21000 Split, Croatia;
| | - Merica Glavina Durdov
- Department of Pathology, University Hospital in Split, School of Medicine, University of Split, 21000 Split, Croatia;
| | - Katarina Vukojevic
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, 21000 Split, Croatia; (I.K.); (N.F.); (B.B.); (K.V.)
| | - Marijan Saraga
- Department of Paediatrics, University Hospital in Split, School of Medicine, University of Split, 21000 Split, Croatia;
| | - Mirna Saraga-Babic
- Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, 21000 Split, Croatia; (I.K.); (N.F.); (B.B.); (K.V.)
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3
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Price GW, Potter JA, Williams BM, Cliff CL, Squires PE, Hills CE. Connexin-mediated cell communication in the kidney: A potential therapeutic target for future intervention of diabetic kidney disease?: Joan Mott Prize Lecture. Exp Physiol 2020; 105:219-229. [PMID: 31785013 DOI: 10.1113/ep087770] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/19/2019] [Indexed: 12/21/2022]
Abstract
The ability of cells to communicate and synchronise their activity is essential for the maintenance of tissue structure, integrity and function. A family of membrane-bound proteins called connexins are largely responsible for mediating the local transfer of information between cells. Assembled in the cell membrane as a hexameric connexon, they either function as a conduit for paracrine signalling, forming a transmembrane hemi-channel, or, if aligned with connexons on neighbouring cells, form a continuous aqueous pore or gap junction, which allows for the direct transmission of metabolic and electrical signals. Regulation of connexin synthesis and activity is critical to cellular function, and a number of diseases are attributed to changes in the expression and/or function of these important proteins. A link between hyperglycaemia, connexin expression, altered nucleotide concentrations and impaired function highlights a potential role for connexin-mediated cell communication in complications of diabetes. In the diabetic kidney, glycaemic injury is the leading cause of end-stage renal failure, reflecting multiple aetiologies including glomerular hyperfiltration, albuminuria, increased deposition of extracellular matrix and tubulointerstitial fibrosis. Loss of connexin-mediated cell-to-cell communication in diabetic nephropathy may represent an early sign of disease progression, but our understanding of the process remains severely limited. This review focuses on recent evidence demonstrating that glucose-evoked changes in connexin-mediated cell communication and associated purinergic signalling may contribute to the pathogenesis of kidney disease in diabetes, highlighting the tantalising potential of targeting these proteins as a novel therapeutic intervention.
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Affiliation(s)
- Gareth W Price
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Joe A Potter
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Bethany M Williams
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Chelsy L Cliff
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Paul E Squires
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
| | - Claire E Hills
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK
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Willebrords J, Crespo Yanguas S, Maes M, Decrock E, Wang N, Leybaert L, Kwak BR, Green CR, Cogliati B, Vinken M. Connexins and their channels in inflammation. Crit Rev Biochem Mol Biol 2016; 51:413-439. [PMID: 27387655 PMCID: PMC5584657 DOI: 10.1080/10409238.2016.1204980] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inflammation may be caused by a variety of factors and is a hallmark of a plethora of acute and chronic diseases. The purpose of inflammation is to eliminate the initial cell injury trigger, to clear out dead cells from damaged tissue and to initiate tissue regeneration. Despite the wealth of knowledge regarding the involvement of cellular communication in inflammation, studies on the role of connexin-based channels in this process have only begun to emerge in the last few years. In this paper, a state-of-the-art overview of the effects of inflammation on connexin signaling is provided. Vice versa, the involvement of connexins and their channels in inflammation will be discussed by relying on studies that use a variety of experimental tools, such as genetically modified animals, small interfering RNA and connexin-based channel blockers. A better understanding of the importance of connexin signaling in inflammation may open up towards clinical perspectives.
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Affiliation(s)
- Joost Willebrords
- Department of In Vitro Toxicology and
Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels,
Belgium; Joost Willebrords: + Tel: 32 2 477 45 87, Michaël Maes: Tel: +32 2
477 45 87, Sara Crespo Yanguas: Tel: +32 2 477 45 87
| | - Sara Crespo Yanguas
- Department of In Vitro Toxicology and
Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels,
Belgium; Joost Willebrords: + Tel: 32 2 477 45 87, Michaël Maes: Tel: +32 2
477 45 87, Sara Crespo Yanguas: Tel: +32 2 477 45 87
| | - Michaël Maes
- Department of In Vitro Toxicology and
Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels,
Belgium; Joost Willebrords: + Tel: 32 2 477 45 87, Michaël Maes: Tel: +32 2
477 45 87, Sara Crespo Yanguas: Tel: +32 2 477 45 87
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Ghent
University, De Pintelaan 185, 9000 Ghent, Belgium; Elke Decrock: Tel: +32 9 332 39
73, Nan Wang: Tel: +32 9 332 39 38, Luc Leybaert: Tel: +32 9 332 33 66
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology Group, Ghent
University, De Pintelaan 185, 9000 Ghent, Belgium; Elke Decrock: Tel: +32 9 332 39
73, Nan Wang: Tel: +32 9 332 39 38, Luc Leybaert: Tel: +32 9 332 33 66
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Ghent
University, De Pintelaan 185, 9000 Ghent, Belgium; Elke Decrock: Tel: +32 9 332 39
73, Nan Wang: Tel: +32 9 332 39 38, Luc Leybaert: Tel: +32 9 332 33 66
| | - Brenda R. Kwak
- Department of Pathology and Immunology and Division of Cardiology,
University of Geneva, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland; Brenda R.
Kwak: Tel: +41 22 379 57 37
| | - Colin R. Green
- Department of Ophthalmology and New Zealand National Eye Centre,
University of Auckland, New Zealand; Colin R. Green: Tel: +64 9 923 61 35
| | - Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal
Science, University of São Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87,
05508-270 São Paulo, Brazil; Bruno Cogliati: Tel: +55 11 30 91 12 00
| | - Mathieu Vinken
- Department of In Vitro Toxicology and
Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels,
Belgium; Joost Willebrords: + Tel: 32 2 477 45 87, Michaël Maes: Tel: +32 2
477 45 87, Sara Crespo Yanguas: Tel: +32 2 477 45 87
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5
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Cogliati B, Mennecier G, Willebrords J, Da Silva TC, Maes M, Pereira IVA, Crespo-Yanguas S, Hernandez-Blazquez FJ, Dagli MLZ, Vinken M. Connexins, Pannexins, and Their Channels in Fibroproliferative Diseases. J Membr Biol 2016; 249:199-213. [PMID: 26914707 DOI: 10.1007/s00232-016-9881-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/16/2016] [Indexed: 12/13/2022]
Abstract
Cellular and molecular mechanisms of wound healing, tissue repair, and fibrogenesis are established in different organs and are essential for the maintenance of function and tissue integrity after cell injury. These mechanisms are also involved in a plethora of fibroproliferative diseases or organ-specific fibrotic disorders, all of which are associated with the excessive deposition of extracellular matrix components. Fibroblasts, which are key cells in tissue repair and fibrogenesis, rely on communicative cellular networks to ensure efficient control of these processes and to prevent abnormal accumulation of extracellular matrix into the tissue. Despite the significant impact on human health, and thus the epidemiologic relevance, there is still no effective treatment for most fibrosis-related diseases. This paper provides an overview of current concepts and mechanisms involved in the participation of cellular communication via connexin-based pores as well as pannexin-based channels in the processes of tissue repair and fibrogenesis in chronic diseases. Understanding these mechanisms may contribute to the development of new therapeutic strategies to clinically manage fibroproliferative diseases and organ-specific fibrotic disorders.
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Affiliation(s)
- Bruno Cogliati
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Brazil
| | - Gregory Mennecier
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Brazil
| | - Joost Willebrords
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Tereza Cristina Da Silva
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Brazil
| | - Michaël Maes
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Sara Crespo-Yanguas
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Maria Lúcia Zaidan Dagli
- Department of Pathology, School of Veterinary Medicine and Animal Science, University of São Paulo, Brazil
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
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6
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Machura K, Neubauer B, Müller H, Tauber P, Kurtz A, Kurtz L. Connexin 40 is dispensable for vascular renin cell recruitment but is indispensable for vascular baroreceptor control of renin secretion. Pflugers Arch 2015; 467:1825-34. [PMID: 25241776 DOI: 10.1007/s00424-014-1615-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 10/24/2022]
Abstract
Defects of the gap junction protein connexin 40 (Cx40) in renin-secreting cells (RSCs) of the kidney lead to a shift of the localization of RSCs from the media layer of afferent arterioles to the periglomerular interstitium. The dislocation of RSCs goes in parallel with elevated plasma renin levels, impaired pressure control of renin secretion, and hypertension. The reasons for the extravascular shift of RSCs and the blunted pressure regulation of renin secretion caused by the absence of Cx40 are still unclear. We have therefore addressed the question if Cx40 is essential for the metaplastic transformation of preglomerular vascular smooth muscle cells (SMCs) into RSCs and if Cx40 is essential for the pressure control of renin secretion from RSCs located in the media layer of afferent arterioles. For our study, we used mice lacking the angiotensin II type 1A (AT1A) receptors, which display a prominent and reversible salt-sensitive metaplastic transformation of SMCs into RSCs. This mouse line was crossed with Cx40-deficient mice to obtain AT1A and Cx40 double deleted mice. The kidneys of AT1A (-/-)Cx40(-/-) mice kept on normal salt (0.3 %) displayed RSCs both in the inner media layer of preglomerular vessels and in the periglomerular interstitium. In contrast to hypotensive AT1A (-/-) (mean bp syst 112 mmHg) and hypertensive Cx40(-/-) (mean bp syst 160 mmHg) mice AT1A (-/-)Cx40(-/-) mice were normotensive(mean bp syst 130 mmHg). Pressure regulation of renin secretion from isolated kidneys was normal in AT1A (-/-) mice, but was absent in AT1A (-/-)Cx40(-/-) mice alike in Cx40(-/-) mice. Low-salt diet (0.02 %) increased RSC numbers in the media layer, whilst high-salt diet (4 %) caused disappearance of RSCs in the media layer but not in the periglomerular interstitium. Blood pressure was clearly salt sensitive both in AT1A (-/-) and in AT1A (-/-)Cx40(-/-) mice but was shifted to higher pressure values in the latter genotype. Our data indicate that Cx40 is not a requirement for intramural vascular localization of RSCs nor for reversible metaplastic transformation of SMCs into RSCs. Therefore, the ectopic localization of RSCs in Cx40(-/-) kidneys is more likely due to a disturbed intercellular communication rather than being the result of chronic overactivation of the renin-angiotensin-aldosterone system or hypertension. Moreover, our findings suggest that Cx40 is a requirement for the pressure control of renin secretion irrespective of the localization of RSCs.
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MESH Headings
- Animals
- Baroreflex
- Blood Pressure
- Cell Movement
- Connexins/deficiency
- Connexins/genetics
- Connexins/metabolism
- Diet, Sodium-Restricted
- Female
- Genotype
- Hypertension/genetics
- Hypertension/metabolism
- Hypertension/physiopathology
- Hypotension/genetics
- Hypotension/metabolism
- Hypotension/physiopathology
- Kidney/blood supply
- Kidney/metabolism
- Mechanotransduction, Cellular
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/metabolism
- Phenotype
- Pressoreceptors/metabolism
- RNA, Messenger/metabolism
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Renin/genetics
- Renin/metabolism
- Renin-Angiotensin System
- Sodium Chloride, Dietary
- Gap Junction alpha-5 Protein
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Affiliation(s)
- Katharina Machura
- Institut für Physiologie, Universität Regensburg, 93053, Regensburg, Germany,
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7
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Hills CE, Price GW, Squires PE. Mind the gap: connexins and cell-cell communication in the diabetic kidney. Diabetologia 2015; 58:233-41. [PMID: 25358446 DOI: 10.1007/s00125-014-3427-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
Abstract
Connexins, assembled as a hexameric connexon, form a transmembrane hemichannel that provides a conduit for paracrine signalling of small molecules and ions to regulate the activity and function of adjacent cells. When hemichannels align and associate with similar channels on opposing cells, they form a continuous aqueous pore or gap junction, allowing the direct transmission of metabolic and electrical signals between coupled cells. Regulation of gap junction synthesis and channel activity is critical for cell function, and a number of diseases can be attributed to changes in the expression/function of these important proteins. Diabetic nephropathy is associated with several complex metabolic and inflammatory responses characterised by defects at the molecular, cellular and tissue level. In both type 1 and type 2 diabetes, glycaemic injury of the kidney is the leading cause of end-stage renal failure, a consequence of multiple aetiologies, including increased deposition of extracellular matrix, glomerular hyperfiltration, albuminuria and tubulointerstitial fibrosis. In diabetic nephropathy, loss of connexin mediated cell-cell communication within the nephron may represent an early sign of disease; however, our current knowledge of the role of connexins in the diabetic kidney is sparse. This review highlights recent evidence demonstrating that maintenance of connexin-mediated cell-cell communication could benefit region-specific renal function in diabetic nephropathy and suggests that these proteins should be viewed as a tantalising novel target for therapeutic intervention.
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Affiliation(s)
- Claire E Hills
- School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK,
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Kurtz A. Connexins, renin cell displacement and hypertension. Curr Opin Pharmacol 2014; 21:1-6. [PMID: 25483714 DOI: 10.1016/j.coph.2014.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Vascular gap junctions formed by specific connexins proteins Cx37, 40, 43 and 45 are important for proper vascular function. This review outlines that defects of the connexin 40 protein leads to hypertension because of dysfunction of renin secreting cells of the kidney. Thus defects of Cx40 but not of other vascular connexins blunt the negative feedback control of renin secretion by the blood pressure, and moreover, lead to a shift of renin expression from the juxtaglomerular vessels walls into the periglomerular interstitium. Evidence exists to indicate that those findings which were primarily obtained with mice are also relevant for humans.
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Affiliation(s)
- Armin Kurtz
- Institute of Physiology, University of Regensburg, Germany.
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