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Buckley C, Lee MD, Zhang X, Wilson C, McCarron JG. Signalling switches maintain intercellular communication in the vascular endothelium. Br J Pharmacol 2024. [PMID: 38651236 DOI: 10.1111/bph.16366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND AND PURPOSE The single layer of cells lining all blood vessels, the endothelium, is a sophisticated signal co-ordination centre that controls a wide range of vascular functions including the regulation of blood pressure and blood flow. To co-ordinate activities, communication among cells is required for tissue level responses to emerge. While a significant form of communication occurs by the propagation of signals between cells, the mechanism of propagation in the intact endothelium is unresolved. EXPERIMENTAL APPROACH Precision signal generation and targeted cellular manipulation was used in conjunction with high spatiotemporal mesoscale Ca2+ imaging in the endothelium of intact blood vessels. KEY RESULTS Multiple mechanisms maintain communication so that Ca2+ wave propagation occurs irrespective of the status of connectivity among cells. Between adjoining cells, regenerative IP3-induced IP3 production transmits Ca2+ signals and explains the propagated vasodilation that underlies the increased blood flow accompanying tissue activity. The inositide is itself sufficient to evoke regenerative phospholipase C-dependent Ca2+ waves across coupled cells. None of gap junctions, Ca2+ diffusion or the release of extracellular messengers is required to support this type of intercellular Ca2+ signalling. In contrast, when discontinuities exist between cells, ATP released as a diffusible extracellular messenger transmits Ca2+ signals across the discontinuity and drives propagated vasodilation. CONCLUSION AND IMPLICATIONS These results show that signalling switches underlie endothelial cell-to-cell signal transmission and reveal how communication is maintained in the face of endothelial damage. The findings provide a new framework for understanding wave propagation and cell signalling in the endothelium.
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Affiliation(s)
- Charlotte Buckley
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Matthew D Lee
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Xun Zhang
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Calum Wilson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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2
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Zhuang W, Mitrou NGA, Kulak S, Cupples WA, Braam B. Modulation of the expression of connexins 37, 40, and 43 in endothelial cells in a culture. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 4:1199198. [PMID: 38558785 PMCID: PMC10978589 DOI: 10.3389/fnetp.2024.1199198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 02/28/2024] [Indexed: 04/04/2024]
Abstract
Connexin (Cx) 37, 40, and 43 are implicated in vascular function, specifically in the electrical coupling of endothelial cells and vascular smooth-muscle cells. In the present study, we investigated whether factors implicated in vascular dysfunction can modulate the gene expression of Cx37, Cx40, and Cx43 and whether this is associated with changes in endothelial layer barrier function in human microvascular endothelial cells (HMEC-1). First, HMEC-1 were subjected to stimuli for 4 and 8 h. We tested their responses to DETA-NONOate, H2O2, high glucose, and angiotensin II, none of which relevantly affected the transcription of the connexin genes. Next, we tested inflammatory factors IL-6, interferon gamma (IFNγ), and TNFα. IFNγ (10 ng/mL) consistently induced Cx40 expression at 4 and 8 h to 10-20-fold when corrected for the control. TNFα and IL-6 resulted in small but significant depressions of Cx37 expression at 4 h. Two JAK inhibitors, epigallocatechin-3-gallate (EGCG) (100-250 μM) and AG490 (100-250 μM), dose-dependently inhibited the induction of Cx40 expression by IFNγ. Subsequently, HMEC-1 were subjected to 10 ng/mL IFNγ for 60 h, and intercellular and transcellular impedance was monitored by electric cell-substrate impedance sensing (ECIS). In response to IFNγ, junctional-barrier impedance increased more than cellular-barrier impedance; this was prevented by AG490 (5 μM). In conclusion, IFNγ can strongly induce Cx40 expression and modify the barrier properties of the endothelial cell membrane through the JAK/STAT pathway. Moreover, the Cx37, Cx40, and Cx43 expression in endothelial cells is stable and, apart from IFNγ, not affected by a number of factors implicated in endothelial dysfunction and vascular diseases.
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Affiliation(s)
- Wenqing Zhuang
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Steve Kulak
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Branko Braam
- Division of Nephrology, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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3
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More HL, Braam B, Cupples WA. Reduced tubuloglomerular feedback activity and absence of its synchronization in a connexin40 knockout rat. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1208303. [PMID: 37705697 PMCID: PMC10495682 DOI: 10.3389/fnetp.2023.1208303] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/10/2023] [Indexed: 09/15/2023]
Abstract
Introduction: Tubuloglomerular feedback (TGF) is the negative feedback component of renal blood flow (RBF) autoregulation. Neighbouring nephrons often exhibit spontaneous TGF oscillation and synchronization mediated by endothelial communication, largely via connexin40 (Cx40). Methods: We had a knockout (KO) rat made that lacks Cx40. One base pair was altered to create a stop codon in exon 1 of Gja5, the gene that encodes Cx40 (the strain is WKY-Gja55em1Mcwi). Blood pressure (BP)-RBF transfer functions probed RBF dynamics and laser speckle imaging interrogated the dynamics of multiple efferent arterioles that reach the surface (star vessels). Results: The distribution of wild type (WT), heterozygote, and KO pups at weaning approximated the Mendelian ratio of 1:2:1; growth did not differ among the three strains. The KO rats were hypertensive. BP-RBF transfer functions showed low gain of the myogenic mechanism and a smaller TGF resonance peak in KO than in WT rats. Laser speckle imaging showed that myogenic mechanism had higher frequency in KO than in WT rats, but similar maximum spectral power. In contrast, the TGF frequency was similar while peak power of its oscillation was much smaller in KO than in WT rats. In WT rats, plots of instantaneous TGF phase revealed BP-independent TGF synchronization among star vessels. The synchronization could be both prolonged and widespread. In KO rats TGF synchronization was not seen, although BP transients could elicit short-lived TGF entrainment. Discussion: Despite the reduced TGF spectral power in KO rats, there was sufficient TGF gain to induce oscillations and therefore enough gain to be effective locally. We conclude that failure to synchronize is dependent, at least in part, on impaired conducted vasomotor responses.
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Affiliation(s)
- Heather L. More
- Department of Biomedical Physiology and Kinesiology, Faculty of Science Simon Fraser University, Burnaby, BC, Canada
| | - Branko Braam
- Division of Nephrology, Department of Medicine, Edmonton, AB, Canada
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | - William A. Cupples
- Department of Biomedical Physiology and Kinesiology, Faculty of Science Simon Fraser University, Burnaby, BC, Canada
- Division of Nephrology, Department of Medicine, Edmonton, AB, Canada
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4
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Benz PM, Frömel T, Laban H, Zink J, Ulrich L, Groneberg D, Boon RA, Poley P, Renne T, de Wit C, Fleming I. Cardiovascular Functions of Ena/VASP Proteins: Past, Present and Beyond. Cells 2023; 12:1740. [PMID: 37443774 PMCID: PMC10340426 DOI: 10.3390/cells12131740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Actin binding proteins are of crucial importance for the spatiotemporal regulation of actin cytoskeletal dynamics, thereby mediating a tremendous range of cellular processes. Since their initial discovery more than 30 years ago, the enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family has evolved as one of the most fascinating and versatile family of actin regulating proteins. The proteins directly enhance actin filament assembly, but they also organize higher order actin networks and link kinase signaling pathways to actin filament assembly. Thereby, Ena/VASP proteins regulate dynamic cellular processes ranging from membrane protrusions and trafficking, and cell-cell and cell-matrix adhesions, to the generation of mechanical tension and contractile force. Important insights have been gained into the physiological functions of Ena/VASP proteins in platelets, leukocytes, endothelial cells, smooth muscle cells and cardiomyocytes. In this review, we summarize the unique and redundant functions of Ena/VASP proteins in cardiovascular cells and discuss the underlying molecular mechanisms.
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Affiliation(s)
- Peter M. Benz
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
| | - Timo Frömel
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Hebatullah Laban
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Joana Zink
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Lea Ulrich
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Dieter Groneberg
- Institute of Physiology I, University of Würzburg, 97070 Würzburg, Germany
| | - Reinier A. Boon
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
- Centre of Molecular Medicine, Institute of Cardiovascular Regeneration, Goethe-University, 60596 Frankfurt am Main, Germany
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Centre, 1081 HZ Amsterdam, The Netherlands
| | - Philip Poley
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Thomas Renne
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Center for Thrombosis and Hemostasis (CTH), Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, D02 VN51 Dublin, Ireland
| | - Cor de Wit
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
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5
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Márquez M, Muñoz M, Córdova A, Puebla M, Figueroa XF. Connexin 40-Mediated Regulation of Systemic Circulation and Arterial Blood Pressure. J Vasc Res 2023; 60:87-100. [PMID: 37331352 DOI: 10.1159/000531035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/05/2023] [Indexed: 06/20/2023] Open
Abstract
Vascular system is a complex network in which different cell types and vascular segments must work in concert to regulate blood flow distribution and arterial blood pressure. Although paracrine/autocrine signaling is involved in the regulation of vasomotor tone, direct intercellular communication via gap junctions plays a central role in the control and coordination of vascular function in the microvascular network. Gap junctions are made up by connexin (Cx) proteins, and among the four Cxs expressed in the cardiovascular system (Cx37, Cx40, Cx43, and Cx45), Cx40 has emerged as a critical signaling pathway in the vessel wall. This Cx is predominantly found in the endothelium, but it is involved in the development of the cardiovascular system and in the coordination of endothelial and smooth muscle cell function along the length of the vessels. In addition, Cx40 participates in the control of vasomotor tone through the transmission of electrical signals from the endothelium to the underlying smooth muscle and in the regulation of arterial blood pressure by renin-angiotensin system in afferent arterioles. In this review, we discuss the participation of Cx40-formed channels in the development of cardiovascular system, control and coordination of vascular function, and regulation of arterial blood pressure.
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Affiliation(s)
- Mónica Márquez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Matías Muñoz
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexandra Córdova
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariela Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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6
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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7
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Fang JS, Burt JM. Connexin37 Regulates Cell Cycle in the Vasculature. J Vasc Res 2022; 60:73-86. [PMID: 36067749 DOI: 10.1159/000525619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/08/2022] [Indexed: 11/19/2022] Open
Abstract
Control of vascular cell growth responses is critical for development and maintenance of a healthy vasculature. Connexins - the proteins comprising gap junction channels - are key regulators of cell growth in diseases such as cancer, but their involvement in controlling cell growth in the vasculature is less well appreciated. Connexin37 (Cx37) is one of four connexin isotypes expressed in the vessel wall. Its primary role in blood vessels relies on its unique ability to transduce flow-sensitive signals into changes in cell cycle status of endothelial (and perhaps, mural) cells. Here, we review available evidence for Cx37's role in the regulation of vascular growth, vessel organization, and vascular tone in healthy and diseased vasculature. We propose a novel mechanism whereby Cx37 accomplishes this with a phosphorylation-dependent transition between closed (growth-suppressive) and multiple open (growth-permissive) channel conformations that result from interactions of the C-terminus with cell-cycle regulators to limit or support cell cycle progression. Lastly, we discuss Cx37 and its downstream signaling as a novel potential target in the treatment of cardiovascular disease, and we address outstanding research questions that still challenge the development of such therapies.
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Affiliation(s)
- Jennifer S Fang
- Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, USA
| | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
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8
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King DR, Sedovy MW, Eaton X, Dunaway LS, Good ME, Isakson BE, Johnstone SR. Cell-To-Cell Communication in the Resistance Vasculature. Compr Physiol 2022; 12:3833-3867. [PMID: 35959755 DOI: 10.1002/cphy.c210040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.
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Affiliation(s)
- D Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Meghan W Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, Virginia, USA
| | - Xinyan Eaton
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Luke S Dunaway
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Miranda E Good
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Scott R Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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9
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Haefliger JA, Meda P, Alonso F. Endothelial Connexins in Developmental and Pathological Angiogenesis. Cold Spring Harb Perspect Med 2022; 12:a041158. [PMID: 35074793 PMCID: PMC9159259 DOI: 10.1101/cshperspect.a041158] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Connexins (Cxs) constitute a large family of transmembrane proteins that form gap junction channels, which enable the direct transfer of small signaling molecules from cell to cell. In blood vessels, Cx channels allow the endothelial cells (ECs) to respond to external and internal cues as a whole and, thus, contribute to the maintenance of vascular homeostasis. While the role of Cxs has been extensively studied in large arteries, a growing body of evidence suggests that they also play a role in the formation of microvascular networks. Since the formation of new blood vessels requires the coordinated response of ECs to external stimuli, endothelial Cxs may play an important role there. Recent studies in developmental and pathologic models reveal that EC Cxs regulate physiological and pathological angiogenesis through canonical and noncanonical functions, making these proteins potential therapeutic targets for the development of new strategies aimed at a better control of angiogenesis.
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Affiliation(s)
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva, Medical Center, 1211 Geneva, Switzerland
| | - Florian Alonso
- Centre de Recherche Cardio-Thoracique de Bordeaux (INSERM U1045), Université de Bordeaux, 33076 Bordeaux, France
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10
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Zehra T, Cupples WA, Braam B. Tubuloglomerular Feedback Synchronization in Nephrovascular Networks. J Am Soc Nephrol 2021; 32:1293-1304. [PMID: 33833078 PMCID: PMC8259654 DOI: 10.1681/asn.2020040423] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To perform their functions, the kidneys maintain stable blood perfusion in the face of fluctuations in systemic BP. This is done through autoregulation of blood flow by the generic myogenic response and the kidney-specific tubuloglomerular feedback (TGF) mechanism. The central theme of this paper is that, to achieve autoregulation, nephrons do not work as single units to manage their individual blood flows, but rather communicate electrically over long distances to other nephrons via the vascular tree. Accordingly, we define the nephrovascular unit (NVU) to be a structure consisting of the nephron, glomerulus, afferent arteriole, and efferent arteriole. We discuss features that require and enable distributed autoregulation mediated by TGF across the kidney. These features include the highly variable topology of the renal vasculature which creates variability in circulation and the potential for mismatch between tubular oxygen demand and delivery; the self-sustained oscillations in each NVU arising from the autoregulatory mechanisms; and the presence of extensive gap junctions formed by connexins and their properties that enable long-distance transmission of TGF signals. The existence of TGF synchronization across the renal microvascular network enables an understanding of how NVUs optimize oxygenation-perfusion matching while preventing transmission of high systemic pressure to the glomeruli, which could lead to progressive glomerular and vascular injury.
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Affiliation(s)
- Tayyaba Zehra
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - William A. Cupples
- Department of Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Branko Braam
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada,Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
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11
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Wolpe AG, Ruddiman CA, Hall PJ, Isakson BE. Polarized Proteins in Endothelium and Their Contribution to Function. J Vasc Res 2021; 58:65-91. [PMID: 33503620 DOI: 10.1159/000512618] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/27/2020] [Indexed: 12/11/2022] Open
Abstract
Protein localization in endothelial cells is tightly regulated to create distinct signaling domains within their tight spatial restrictions including luminal membranes, abluminal membranes, and interendothelial junctions, as well as caveolae and calcium signaling domains. Protein localization in endothelial cells is also determined in part by the vascular bed, with differences between arteries and veins and between large and small arteries. Specific protein polarity and localization is essential for endothelial cells in responding to various extracellular stimuli. In this review, we examine protein localization in the endothelium of resistance arteries, with occasional references to other vessels for contrast, and how that polarization contributes to endothelial function and ultimately whole organism physiology. We highlight the protein localization on the luminal surface, discussing important physiological receptors and the glycocalyx. The protein polarization to the abluminal membrane is especially unique in small resistance arteries with the presence of the myoendothelial junction, a signaling microdomain that regulates vasodilation, feedback to smooth muscle cells, and ultimately total peripheral resistance. We also discuss the interendothelial junction, where tight junctions, adherens junctions, and gap junctions all convene and regulate endothelial function. Finally, we address planar cell polarity, or axial polarity, and how this is regulated by mechanosensory signals like blood flow.
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Affiliation(s)
- Abigail G Wolpe
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Claire A Ruddiman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Phillip J Hall
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA, .,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA,
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12
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Schmidt K, de Wit C. Endothelium-Derived Hyperpolarizing Factor and Myoendothelial Coupling: The in vivo Perspective. Front Physiol 2021; 11:602930. [PMID: 33424626 PMCID: PMC7786115 DOI: 10.3389/fphys.2020.602930] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
The endothelium controls vascular tone adopting blood flow to tissue needs. It releases chemical mediators [e.g., nitric oxide (NO), prostaglandins (PG)] and exerts appreciable dilation through smooth muscle hyperpolarization, thus termed endothelium-dependent hyperpolarization (EDH). Initially, EDH was attributed to release of a factor, but later it was suggested that smooth muscle hyperpolarization might be derived from radial spread of an initial endothelial hyperpolarization through heterocellular channels coupling these vascular cells. The channels are indeed present and formed by connexins that enrich in gap junctions (GJ). In vitro data suggest that myoendothelial coupling underlies EDH-type dilations as evidenced by blocking experiments as well as simultaneous, merely identical membrane potential changes in endothelial and smooth muscle cells (SMCs), which is indicative of coupling through ohmic resistors. However, connexin-deficient animals do not display any attenuation of EDH-type dilations in vivo, and endothelial and SMCs exhibit distinct and barely superimposable membrane potential changes exerted by different means in vivo. Even if studied in the exact same artery EDH-type dilation exhibits distinct features in vitro and in vivo: in isometrically mounted vessels, it is rather weak and depends on myoendothelial coupling through connexin40 (Cx40), whereas in vivo as well as in vitro under isobaric conditions it is powerful and independent of myoendothelial coupling through Cx40. It is concluded that EDH-type dilations are distinct and a significant dependence on myoendothelial coupling in vitro does not reflect the situation under physiologic conditions in vivo. Myoendothelial coupling may act as a backup mechanism that is uncovered in the absence of the powerful EDH-type response and possibly reflects a situation in a pathophysiologic environment.
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Affiliation(s)
- Kjestine Schmidt
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - Cor de Wit
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany.,Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
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Si R, Zhang Q, Cabrera JTO, Zheng Q, Tsuji‐Hosokawa A, Watanabe M, Hosokawa S, Xiong M, Jain PP, Ashton AW, Yuan JX, Wang J, Makino A. Chronic Hypoxia Decreases Endothelial Connexin 40, Attenuates Endothelium-Dependent Hyperpolarization-Mediated Relaxation in Small Distal Pulmonary Arteries, and Leads to Pulmonary Hypertension. J Am Heart Assoc 2020; 9:e018327. [PMID: 33307937 PMCID: PMC7955394 DOI: 10.1161/jaha.120.018327] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/02/2020] [Indexed: 11/17/2022]
Abstract
Background Abnormal endothelial function in the lungs is implicated in the development of pulmonary hypertension; however, there is little information about the difference of endothelial function between small distal pulmonary artery (PA) and large proximal PA and their contribution to the development of pulmonary hypertension. Herein, we investigate endothelium-dependent relaxation in different orders of PAs and examine the molecular mechanisms by which chronic hypoxia attenuates endothelium-dependent pulmonary vasodilation, leading to pulmonary hypertension. Methods and Results Endothelium-dependent relaxation in large proximal PAs (second order) was primarily caused by releasing NO from the endothelium, whereas endothelium-dependent hyperpolarization (EDH)-mediated vasodilation was prominent in small distal PAs (fourth-fifth order). Chronic hypoxia abolished EDH-mediated relaxation in small distal PAs without affecting smooth muscle-dependent relaxation. RNA-sequencing data revealed that, among genes related to EDH, the levels of Cx37, Cx40, Cx43, and IK were altered in mouse pulmonary endothelial cells isolated from chronically hypoxic mice in comparison to mouse pulmonary endothelial cells from normoxic control mice. The protein levels were significantly lower for connexin 40 (Cx40) and higher for connexin 37 in mouse pulmonary endothelial cells from hypoxic mice than normoxic mice. Cx40 knockout mice exhibited significant attenuation of EDH-mediated relaxation and marked increase in right ventricular systolic pressure. Interestingly, chronic hypoxia led to a further increase in right ventricular systolic pressure in Cx40 knockout mice without altering EDH-mediated relaxation. Furthermore, overexpression of Cx40 significantly decreased right ventricular systolic pressure in chronically hypoxic mice. Conclusions These data suggest that chronic hypoxia-induced downregulation of endothelial Cx40 results in impaired EDH-mediated relaxation in small distal PAs and contributes to the development of pulmonary hypertension.
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Affiliation(s)
- Rui Si
- Department of PhysiologyThe University of ArizonaTucsonAZ
| | - Qian Zhang
- Department of PhysiologyThe University of ArizonaTucsonAZ
- State Key Laboratory of Respiratory DiseaseThe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
| | | | - Qiuyu Zheng
- Department of MedicineUniversity of CaliforniaSan DiegoCA
- State Key Laboratory of Respiratory DiseaseThe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
| | | | | | | | - Mingmei Xiong
- Department of MedicineUniversity of CaliforniaSan DiegoCA
- State Key Laboratory of Respiratory DiseaseThe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
| | | | - Anthony W. Ashton
- Division of Perinatal ResearchKolling Institute of Medical ResearchUniversity of SydneyNew South WalesAustralia
| | - Jason X.‐J. Yuan
- Department of MedicineThe University of ArizonaTucsonAZ
- Department of MedicineUniversity of CaliforniaSan DiegoCA
| | - Jian Wang
- Department of MedicineThe University of ArizonaTucsonAZ
- Department of MedicineUniversity of CaliforniaSan DiegoCA
- State Key Laboratory of Respiratory DiseaseThe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
| | - Ayako Makino
- Department of PhysiologyThe University of ArizonaTucsonAZ
- Department of MedicineThe University of ArizonaTucsonAZ
- Department of MedicineUniversity of CaliforniaSan DiegoCA
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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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15
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Mensah SA, Nersesyan AA, Ebong EE. Endothelial Glycocalyx-Mediated Intercellular Interactions: Mechanisms and Implications for Atherosclerosis and Cancer Metastasis. Cardiovasc Eng Technol 2020; 12:72-90. [PMID: 33000443 PMCID: PMC7904750 DOI: 10.1007/s13239-020-00487-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/11/2020] [Indexed: 12/21/2022]
Abstract
Purpose The endothelial glycocalyx (GCX) plays a critical role in the health of the vascular system. Degradation of the GCX has been implicated in the onset of diseases like atherosclerosis and cancer because it disrupts endothelial cell (EC) function that is meant to protect from atherosclerosis and cancer. Examples of such EC function include interendothelial cell communication via gap junctions and receptor-mediated interactions between endothelial and tumor cells. This review focuses on GCX-dependent regulation of these intercellular interactions in healthy and diseased states. The ultimate goal is to build new knowledge that can be applied to developing GCX regeneration strategies that can control intercellular interaction in order to combat the progression of diseases such as atherosclerosis and cancer. Methods In vitro and in vivo studies were conducted to determine the baseline expression of GCX in physiologically relevant conditions. Chemical and mechanical GCX degradation approaches were employed to degrade the GCX. The impact of intact versus degraded GCX on intercellular interactions was assessed using cytochemistry, histochemistry, a Lucifer yellow dye transfer assay, and confocal, intravital, and scanning electron microscopy techniques. Results Relevant to atherosclerosis, we found that GCX stability determines the expression and functionality of Cx43 in gap junction-mediated EC-to-EC communication. Relevant to cancer metastasis, we found that destabilizing the GCX through either disturbed flow-induced or enzyme induced GCX degradation results in increased E-selectin receptor-mediated EC-tumor cell interactions. Conclusion Our findings lay a foundation for future endothelial GCX-targeted therapy, to control intercellular interactions and limit the progression of atherosclerosis and cancer.
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Affiliation(s)
- Solomon A Mensah
- Department of Bioengineering, Northeastern University, Boston, MA, USA.,Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Alina A Nersesyan
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Eno E Ebong
- Department of Bioengineering, Northeastern University, Boston, MA, USA. .,Department of Chemical Engineering, Northeastern University, 360 Huntington Avenue, 335 Interdisciplinary Science and Engineering Complex, Boston, MA, 02115, USA. .,Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, USA.
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16
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Li Y, Aziz Q, Anderson N, Ojake L, Tinker A. Endothelial ATP-Sensitive Potassium Channel Protects Against the Development of Hypertension and Atherosclerosis. Hypertension 2020; 76:776-784. [PMID: 32654556 PMCID: PMC7418932 DOI: 10.1161/hypertensionaha.120.15355] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/18/2020] [Accepted: 06/19/2020] [Indexed: 12/28/2022]
Abstract
In the endothelium, ATP-sensitive potassium (KATP) channels are thought to couple cellular metabolism with membrane excitability, calcium entry, and endothelial mediator release. We hypothesized that endothelial KATP channels have a broad role protecting against high blood pressure and atherosclerosis. Endothelial-specific Kir6.1 KO mice (eKO) and eKO mice on an apolipoprotein E KO background were generated (A-eKO) to investigate the role of KATP channels in the endothelium. Basal blood pressure was not elevated in eKO mice. However, when challenged with a high-salt diet and the eNOS inhibitor L-NAME, eKO mice became more hypertensive than their littermate controls. In aorta, NO release at least partly contributes to the endothelium-dependent vasorelaxation induced by pinacidil. In A-eKO mice atherosclerotic plaque density was significantly greater than in their littermate controls when challenged with a high-fat diet, particularly in the aortic arch region. Levels of endothelial dysfunction markers were higher in eKO compared with WT mice; however, these were not significant for A-eKO mice compared with their littermate controls. Furthermore, decreased vascular reactivity was observed in the mesenteric arteries of A-eKO mice, but not in aorta when on a high-fat diet. Our data support a role for endothelial Kir6.1-containing KATP channels in the endothelial protection against environmental stressors: the maintenance of blood pressure homeostasis in response to high salt and endothelial integrity when challenged with a high-fat diet.
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Affiliation(s)
- Yiwen Li
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Qadeer Aziz
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Naomi Anderson
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Leona Ojake
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
| | - Andrew Tinker
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom
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Møller S, Jacobsen JCB, Holstein-Rathlou NH, Sorensen CM. Lack of Connexins 40 and 45 Reduces Local and Conducted Vasoconstrictor Responses in the Murine Afferent Arterioles. Front Physiol 2020; 11:961. [PMID: 32848881 PMCID: PMC7431600 DOI: 10.3389/fphys.2020.00961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 07/15/2020] [Indexed: 01/07/2023] Open
Abstract
The juxtaglomerular apparatus (JGA) is an essential structure in the regulation of renal function. The JGA embodies two major functions: tubuloglomerular feedback (TGF) and renin secretion. TGF is one of the mechanisms mediating renal autoregulation. It is initiated by an increase in tubular NaCl concentration at the macula densa cells. This induces a local afferent arteriolar vasoconstriction and a conducted response that can be measured several 100 μm upstream from the juxtaglomerular segment. This spread of the vasomotor response into the surrounding vasculature likely plays a key role in renal autoregulation, and it requires the presence of gap junctions, intercellular pores based on connexin (Cx) proteins. Several Cx isoforms are expressed in the JGA and in the arteriolar wall. Disruption of this communication pathway is associated with reduced TGF, dysregulation of renin secretion, and hypertension. We examine if the absence of Cx40 or Cx45, expressed in the endothelial and vascular smooth muscle cells respectively, attenuates afferent arteriolar local and conducted vasoconstriction. Afferent arterioles from wildtype and Cx-deficient mice (Cx40 and Cx45) were studied using the isolated perfused juxtamedullary nephron preparation. Vasoconstriction was induced via electrical pulse stimulation at the glomerular entrance. Inner afferent arteriolar diameter was measured locally and upstream to evaluate conducted vasoconstriction. Electrical stimulation induced local vasoconstriction in all groups. The local vasoconstriction was significantly smaller when Cx40 was absent. The vasoconstriction decreased in magnitude with increasing distance from the stimulation site. In both Cx40 and Cx45 deficient mice, the vasoconstriction conducted a shorter distance along the vessel compared to wild-type mice. In Cx40 deficient arterioles, this may be caused by a smaller local vasoconstriction. Collectively, these findings imply that Cx40 and Cx45 are central for normal vascular reactivity and, therefore, likely play a key role in TGF-induced regulation of afferent arteriolar resistance.
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Affiliation(s)
- Sophie Møller
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Christian Brings Jacobsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels-Henrik Holstein-Rathlou
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sorensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
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Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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19
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Lan SH, Lai WT, Zheng SY, Yang L, Fang LC, Zhou L, Tang B, Duan J, Hong T. Upregulation of Connexin 40 Mediated by Nitric Oxide Attenuates Cerebral Vasospasm After Subarachnoid Hemorrhage via the Nitric Oxide-Cyclic Guanosine Monophosphate-Protein Kinase G Pathway. World Neurosurg 2020; 136:e476-e486. [PMID: 31953101 DOI: 10.1016/j.wneu.2020.01.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The present study was performed to elucidate the role of nitric oxide (NO) and connexin 40 (Cx40) in the induction of cerebral vasospasm after subarachnoid hemorrhage (SAH) in vivo. METHODS A SAH rat model was established using the double-bleed method. A total of 108 Sprague-Dawley rats weighing 250-300 g were randomly divided into 6 groups: SAH; SAH plus diethylenetriamine (DETA)/NO (exogenous NO donor); SAH plus 8-bromoadenosine (8-Br)-cyclic guanosine monophosphate (cGMP; protein kinase G [PKG] activator); SAH plus DETA/NO plus KT5823 (PKG inhibitor); SAH plus DETA/NO plus 40Gap27 (Cx40 inhibitor); and sham. The changes in the diameter of the branch microvessels in the middle cerebral artery were recorded. The neurological score was evaluated using the Garcia scoring system. Basilar artery (BA) tension was measured using the Danish Myo Technology myograph system. Cx40 protein expression was analyzed using immunofluorescence and Western blotting. Endothelial NO synthase, soluble guanylate cyclase, and PKG protein expression were measured by Western blotting. RESULTS A considerable narrowing of the cerebral vessels was detected in the SAH group compared with that in the sham group. Moreover, compared with the sham group, the SAH group showed a marked decrease in Cx40, endothelial NO synthase, soluble guanylate cyclase, and PKG expression. The expression of Cx40 and PKG were obviously higher in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups than in the SAH group. However, Cx40 was lower in the SAH plus DETA/NO plus KT5823 and SAH plus DETA/NO plus 40Gap27 groups than in the SAH plus ETA/NO group. The BAs showed significant vasodilation in the SAH plus DETA/NO and SAH plus 8-Br-cGMP groups. However, the vasodilation response of BAs was inhibited in the SAH plus DETA/NO plus KT5823 and SAH plus DETA-NO plus 40Gap27 groups. CONCLUSIONS The NO-cGMP-PKG pathway alleviated cerebral vasospasm via Cx40 upregulation.
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Affiliation(s)
- Shi Hai Lan
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wen Tao Lai
- Department of Neurosurgery, Affiliated Ganzhou Hospital of Nanchang University, Ganzhou, China
| | - Su Yue Zheng
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Le Yang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lin Chun Fang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lin Zhou
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Bin Tang
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jian Duan
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Tao Hong
- Department of Neurosurgery, First Affiliated Hospital of Nanchang University, Nanchang, China.
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Zechariah A, Tran CHT, Hald BO, Sandow SL, Sancho M, Kim MSM, Fabris S, Tuor UI, Gordon GR, Welsh DG. Intercellular Conduction Optimizes Arterial Network Function and Conserves Blood Flow Homeostasis During Cerebrovascular Challenges. Arterioscler Thromb Vasc Biol 2020; 40:733-750. [PMID: 31826653 PMCID: PMC7058668 DOI: 10.1161/atvbaha.119.313391] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Cerebral arterial networks match blood flow delivery with neural activity. Neurovascular response begins with a stimulus and a focal change in vessel diameter, which by themselves is inconsequential to blood flow magnitude, until they spread and alter the contractile status of neighboring arterial segments. We sought to define the mechanisms underlying integrated vascular behavior and considered the role of intercellular electrical signaling in this phenomenon. Approach and Results: Electron microscopic and histochemical analysis revealed the structural coupling of cerebrovascular cells and the expression of gap junctional subunits at the cell interfaces, enabling intercellular signaling among vascular cells. Indeed, robust vasomotor conduction was detected in human and mice cerebral arteries after focal vessel stimulation: a response attributed to endothelial gap junctional communication, as its genetic alteration attenuated this behavior. Conducted responses were observed to ascend from the penetrating arterioles, influencing the contractile status of cortical surface vessels, in a simulated model of cerebral arterial network. Ascending responses recognized in vivo after whisker stimulation were significantly attenuated in mice with altered endothelial gap junctional signaling confirming that gap junctional communication drives integrated vessel responses. The diminishment in vascular communication also impaired the critical ability of the cerebral vasculature to maintain blood flow homeostasis and hence tissue viability after stroke. CONCLUSIONS Our findings highlight the integral role of intercellular electrical signaling in transcribing focal stimuli into coordinated changes in cerebrovascular contractile activity and expose, a hitherto unknown mechanism for flow regulation after stroke.
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Affiliation(s)
- Anil Zechariah
- Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Cam Ha T. Tran
- Hotchkiss Brain Institute, Libin Cardiovascular Institute and the Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, USA 89557
| | - Bjorn O. Hald
- Department of Neuroscience, Translational Neurobiology, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Shaun L. Sandow
- University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland 4558 Australia
| | - Maria Sancho
- Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Michelle Sun Mi Kim
- Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Sergio Fabris
- Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Ursula I. Tuor
- Hotchkiss Brain Institute, Libin Cardiovascular Institute and the Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Grant R.J. Gordon
- Hotchkiss Brain Institute, Libin Cardiovascular Institute and the Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Donald G. Welsh
- Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada N6A 5B7
- Hotchkiss Brain Institute, Libin Cardiovascular Institute and the Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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Basic Concepts of the Microcirculation. Microcirculation 2020. [DOI: 10.1007/978-3-030-28199-1_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Yang L, Yan J, Zhang JA, Zhou XH, Fang C, Zeng EM, Tang B, Duan J, Lu GH, Hong T. The important role of connexin 43 in subarachnoid hemorrhage-induced cerebral vasospasm. J Transl Med 2019; 17:433. [PMID: 31888653 PMCID: PMC6936071 DOI: 10.1186/s12967-019-02190-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/23/2019] [Indexed: 12/23/2022] Open
Abstract
Background Gap junctions are involved in the development of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH). However, the specific roles and regulatory functions of related connexin isoforms remain unknown. The aim of this study was to investigate the importance of connexin 43 (Cx43) in CVS and determine whether Cx43 alterations are modulated via the protein kinase C (PKC) signaling transduction pathway. Methods Oxyhemoglobin (OxyHb)-induced smooth muscle cells of basilar arterial and second-injection model in rat were used as CVS models in vitro and in vivo. In addition, dye transfer assays were used for gap junction-mediated intercellular communication (GJIC) observation in vitro and delayed cerebral ischemia (DCI) was observed in vivo by perfusion-weighted imaging (PWI) and intravital fluorescence microscopy. Results Increase in Cx43 mediated the development of SAH-induced CVS was found in both in vitro and in vivo CVS models. Enhanced GJIC was observed in vitro CVS model, this effect and increased Cx43 were reversed by preincubation with specific PKC inhibitors (chelerythrine or GF 109203X). DCI was observed in vivo on day 7 after SAH. However, DCI was attenuated by pretreatment with Cx43 siRNA or PKC inhibitors, and the increased Cx43 expression in vivo was also reversed by Cx43 siRNA or PKC inhibitors. Conclusions These data provide strong evidence that Cx43 plays an important role in CVS and indicate that changes in Cx43 expression may be mediated by the PKC pathway. The current findings suggest that Cx43 and the PKC pathway are novel targets for developing treatments for SAH-induced CVS.
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Affiliation(s)
- Le Yang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Jian Yan
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Jin-An Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Xin-Hui Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Chao Fang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Er-Ming Zeng
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Bin Tang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Jian Duan
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Guo-Hui Lu
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China
| | - Tao Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, 17 Yong Wai Zheng Street, Nanchang, China.
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Melchert J, Henningfeld KA, Richts S, Lingner T, Jonigk D, Pieler T. The secreted BMP antagonist ERFE is required for the development of a functional circulatory system in Xenopus. Dev Biol 2019; 459:138-148. [PMID: 31846624 DOI: 10.1016/j.ydbio.2019.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/03/2019] [Accepted: 12/12/2019] [Indexed: 01/24/2023]
Abstract
The hormone Erythroferrone (ERFE) is a member of the C1q/TNF-related protein family that regulates iron homeostasis through the suppression of hamp. In a gain of function screen in Xenopus embryos, we identified ERFE as a potent secondary axis-inducing agent. Experiments in Xenopus embryos and ectodermal explants revealed that ERFE functions as a selective inhibitor of the BMP pathway and the conserved C1q domain is not required for this activity. Inhibition occurs at the extracelluar level, through the interaction of ERFE with the BMP ligand. During early Xenopus embryogenesis, erfe is first expressed in the ventral blood islands where initial erythropoiesis occurs and later in circulating blood cells. ERFE knockdown does not alter the expression of etv.2, aplnr and flt1 in tailbud stage embryos indicating endothelial cell specification is independent of ERFE. However, in tadpole embryos, defects of the vascular network and primitive blood circulation are observed as well as edema formation. RNAseq analysis of ERFE morphant embryos also revealed the inhibition of gja4 indicating disruption of dorsal aorta formation.
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Affiliation(s)
- Juliane Melchert
- Institute of Developmental Biochemistry, University Medical Center Göttingen, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany.
| | - Kristine A Henningfeld
- Institute of Developmental Biochemistry, University Medical Center Göttingen, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
| | - Sven Richts
- Institute of Developmental Biochemistry, University Medical Center Göttingen, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
| | - Thomas Lingner
- Transcriptome and Genome Analysis Laboratory, University Medical Center Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Danny Jonigk
- Institut für Pathologie, Medizinische Hochschule Hannover (MHH) Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Tomas Pieler
- Institute of Developmental Biochemistry, University Medical Center Göttingen, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Justus-von-Liebig-Weg 11, 37077, Goettingen, Germany
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24
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Hautefort A, Pfenniger A, Kwak BR. Endothelial connexins in vascular function. VASCULAR BIOLOGY 2019; 1:H117-H124. [PMID: 32923963 PMCID: PMC7439941 DOI: 10.1530/vb-19-0015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/07/2019] [Indexed: 12/22/2022]
Abstract
Gap junctions are essential for intercellular crosstalk in blood and lymphatic vasculature. These clusters of intercellular channels ensure direct communication among endothelial cells and between endothelial and smooth muscle cells, and the synchronization of their behavior along the vascular tree. Gap junction channels are formed by connexins; six connexins form a connexon or hemichannel and the docking of two connexons result in a full gap junction channel allowing for the exchange of ions and small metabolites between neighboring cells. Recent evidence indicates that the intracellular domains of connexins may also function as an interaction platform (interactome) for other proteins, thereby regulating their function. Interestingly, fragments of Cx proteins generated by alternative internal translation were recently described, although their functions in the vascular wall remain to be uncovered. Variations in connexin expression are observed along different types of blood and lymphatic vessels; the most commonly found endothelial connexins are Cx37, Cx40, Cx43 and Cx47. Physiological studies on connexin-knockout mice demonstrated the essential roles of these channel-forming proteins in the coordination of vasomotor activity, endothelial permeability and inflammation, angiogenesis and in the maintenance of fluid balance in the body.
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Affiliation(s)
- Aurélie Hautefort
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Anna Pfenniger
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.,Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.,Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
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25
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Ivanova E, Kovacs-Oller T, Sagdullaev BT. Domain-specific distribution of gap junctions defines cellular coupling to establish a vascular relay in the retina. J Comp Neurol 2019; 527:2675-2693. [PMID: 30950036 PMCID: PMC6721971 DOI: 10.1002/cne.24699] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022]
Abstract
In the retina, diverse functions of neuronal gap junctions (GJs) have been established. However, the distribution and function of vascular GJs are less clear. Here in the mouse retina whole mounts, we combined structural immunohistochemical analysis and a functional assessment of cellular coupling with a GJ-permeable tracer Neurobiotin to determine distribution patterns of three major vascular connexins. We found that Cx43 was expressed in punctate fashion on astroglia, surrounding all types of blood vessels and in continuous string-like structures along endothelial cell contacts in specialized regions of the vascular tree. Specifically, these Cx43-positive strings originated at the finest capillaries and extended toward the feeding artery. As this structural arrangement promoted strong and exclusive coupling of pericytes and endothelial cells along the corresponding branch, we termed this region a "vascular relay." Cx40 expression was found predominantly along the endothelial cell contacts of the primary arteries and did not overlap with Cx43-positive strings. At their occupied territories, Cx43 and Cx40 clustered with tight junctions and, to a lesser extent, with adhesion contacts, both key elements of the blood-retina barrier. Finally, Cx37 puncta were associated with the entire surface of both mural and endothelial cells across all regions of the vascular tree. This combinatorial analysis of vascular connexins and identification of the vascular relay region will serve as a structural foundation for future studies of neurovascular signaling in health and disease.
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Affiliation(s)
- Elena Ivanova
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
| | - Tamas Kovacs-Oller
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
| | - Botir T Sagdullaev
- Burke Neurological Institute, Department of Ophthalmology, Weill Cornell Medicine, White Plains, New York
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26
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Maibier M, Bintig W, Goede A, Höpfner M, Kuebler WM, Secomb TW, Nitzsche B, Pries AR. Gap junctions regulate vessel diameter in chick chorioallantoic membrane vasculature by both tone-dependent and structural mechanisms. Microcirculation 2019; 27:e12590. [PMID: 31520425 DOI: 10.1111/micc.12590] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/21/2019] [Accepted: 09/09/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVE In this study, we examined the impact of gap junction blockade on chick chorioallantoic membrane microvessels. METHODS Expression of Cx37, Cx40/42, and Cx43 in chick chorioallantoic membrane tissue was studied by PCR, Western blot, and confocal immunofluorescence microscopy. Vessel diameter changes occurring under gap junction blockade with carbenoxolone (175 µmol/L), palmitoleic acid (100 µmol/L), 43 GAP27 (1 mmol/L) were analyzed by intravital microscopy. To analyze vascular tone, chick chorioallantoic membrane vessels were exposed to a vasodilator cocktail consisting of acetylcholine (10 μmol/L), adenosine (100 μmol/L), papaverine (200 μmol/L), and sodium nitroprusside (10 μmol/L). RESULTS In chick chorioallantoic membrane lysates, Western blot analysis revealed the expression of Cx40 and Cx43. Immunofluorescence in intact chick chorioallantoic membrane vasculature showed only Cx43, limited to arterial vessel walls. Upon gap junction blockade (3 hours) arterial and venous diameters decreased to 0.50 ± 0.03 and 0.36 ± 0.06 (carbenoxolone), 0.72 ± 0.08 and 0.63 ± 0.15 (palmitoleic acid) and 0.77 ± 0.004 and 0.58 ± 0.05 (GAP27), relative to initial values. Initially, diameter decrease was dominated by increasing vascular tone. After 6 hours, however, vessel tone was reduced, suggesting structural network remodeling. CONCLUSIONS Our findings suggest a major role for connexins in mediating acute and chronic diameter changes in developing vascular networks.
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Affiliation(s)
- Martin Maibier
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Willem Bintig
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Biochemistry & Neuro Cure Cluster of Excellence, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Andrean Goede
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Michael Höpfner
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Wolfgang M Kuebler
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
- Departments of Surgery and Physiology, University of Toronto, Toronto, ON, Canada
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Bianca Nitzsche
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Axel R Pries
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin, Germany
- German Heart Center Berlin, Berlin, Germany
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27
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Davila A, Tian Y, Czikora I, Li J, Su H, Huo Y, Patel V, Robinson V, Kapuku G, Weintraub N, Bagi Z. Adenosine Kinase Inhibition Augments Conducted Vasodilation and Prevents Left Ventricle Diastolic Dysfunction in Heart Failure With Preserved Ejection Fraction. Circ Heart Fail 2019; 12:e005762. [PMID: 31525084 DOI: 10.1161/circheartfailure.118.005762] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Heart failure with preserved ejection fraction (HFpEF) is often manifested as impaired cardiovascular reserve. We sought to determine if conducted vasodilation, which coordinates microvascular resistance longitudinally to match tissue metabolic demand, becomes compromised in HFpEF. We hypothesized that the metabolic vasodilator adenosine facilitates and that inhibition of ADK (adenosine kinase) augments conducted vasodilation for a more efficient myocardial perfusion and improved left ventricle (LV) diastolic function in HFpEF. METHODS AND RESULTS We assessed conducted vasodilation in obese ZSF1 rats that develop LV diastolic dysfunction and is used to model human HFpEF. Additionally, conducted vasodilation was measured in arterioles isolated from the right atrial appendages of patients with HFpEF. We found a markedly reduced conducted vasodilation both in obese ZSF1 rats and in patients with HFpEF. Impaired conducted vasodilation was accompanied by increased vascular ADK expression. Isolated rat and human arterioles incubated with adenosine (10 nmol/L) or ADK inhibitor ABT-702 (0.1 µmol/L) both displayed augmented conducted vasodilation. Treatment of obese ZSF1 rats with ABT-702 (1.5 mg/kg, IP for 8 weeks) prevented LV diastolic dysfunction, and in a crossover design augmented conducted vasodilation and improved LV diastolic function. ABT-702 treated obese ZSF1 rats exhibited reduced expression of myocardial carbonic anhydrase 9 and collagen, surrogate markers of myocardial hypoxia. CONCLUSIONS Upregulation of vascular ADK mitigates adenosine-facilitated conducted vasodilation in obese ZSF1 rats and in patients with HFpEF. We propose that pharmacological inhibition of ADK could be beneficial for therapeutic augmentation of conducted vasodilation, thereby improving tissue perfusion and LV diastolic function in HFpEF.
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Affiliation(s)
- Alec Davila
- Department of Physiology (A.D., Y.T., I.C., Z.B.), Medical College of Georgia, Augusta University
| | - Yanna Tian
- Department of Physiology (A.D., Y.T., I.C., Z.B.), Medical College of Georgia, Augusta University
| | - Istvan Czikora
- Department of Physiology (A.D., Y.T., I.C., Z.B.), Medical College of Georgia, Augusta University
| | - Jie Li
- Vascular Biology Center (J.L., H.S., Y.H., N.W.), Medical College of Georgia, Augusta University
| | - Huabo Su
- Vascular Biology Center (J.L., H.S., Y.H., N.W.), Medical College of Georgia, Augusta University
| | - Yuqing Huo
- Vascular Biology Center (J.L., H.S., Y.H., N.W.), Medical College of Georgia, Augusta University
| | - Vijay Patel
- Department of Surgery (V.P.), Medical College of Georgia, Augusta University
| | - Vincent Robinson
- Division of Cardiology (V.R., N.W.), Medical College of Georgia, Augusta University
| | - Gaston Kapuku
- Department of Medicine, Georgia Prevention Institute, Department of Population Health Sciences (G.K.), Medical College of Georgia, Augusta University
| | - Neal Weintraub
- Vascular Biology Center (J.L., H.S., Y.H., N.W.), Medical College of Georgia, Augusta University.,Division of Cardiology (V.R., N.W.), Medical College of Georgia, Augusta University
| | - Zsolt Bagi
- Department of Physiology (A.D., Y.T., I.C., Z.B.), Medical College of Georgia, Augusta University
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28
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CGRP signalling inhibits NO production through pannexin-1 channel activation in endothelial cells. Sci Rep 2019; 9:7932. [PMID: 31138827 PMCID: PMC6538758 DOI: 10.1038/s41598-019-44333-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/13/2019] [Indexed: 02/07/2023] Open
Abstract
Blood flow distribution relies on precise coordinated control of vasomotor tone of resistance arteries by complex signalling interactions between perivascular nerves and endothelial cells. Sympathetic nerves are vasoconstrictors, whereas endothelium-dependent NO production provides a vasodilator component. In addition, resistance vessels are also innervated by sensory nerves, which are activated during inflammation and cause vasodilation by the release of calcitonin gene-related peptide (CGRP). Inflammation leads to superoxide anion (O2• -) formation and endothelial dysfunction, but the involvement of CGRP in this process has not been evaluated. Here we show a novel mechanistic relation between perivascular sensory nerve-derived CGRP and the development of endothelial dysfunction. CGRP receptor stimulation leads to pannexin-1-formed channel opening and the subsequent O2• --dependent connexin-based hemichannel activation in endothelial cells. The prolonged opening of these channels results in a progressive inhibition of NO production. These findings provide new therapeutic targets for the treatment of the inflammation-initiated endothelial dysfunction.
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29
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Sorensen CM, Cupples WA. Myoendothelial communication in the renal vasculature and the impact of drugs used clinically to treat hypertension. Curr Opin Pharmacol 2019; 45:49-56. [PMID: 31071677 DOI: 10.1016/j.coph.2019.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/04/2019] [Indexed: 12/11/2022]
Abstract
The renal vasculature has many peculiarities including highly irregular branching. Renal blood flow must sustain adequate perfusion and maintain a high glomerular filtration. Renal autoregulation helps control renal blood flow. The local autoregulatory mechanism, tubuloglomerular feedback, elicits a vasoconstriction that can be found not only in neighboring nephrons but over large areas of the kidney indicating that the renal vasculature supports strong conduction of vascular responses. The basis for conduction is intercellular communication through gap junctions. The endothelium is strongly coupled and serves as a vascular conduction highway leading the signal to the vascular smooth muscle cells through myoendothelial coupling. Extensive intercellular coupling is also found in renin secreting cells where gap junctions seem to tie the cells together to improve control of renin secretion. Lack of coupling leads to dysregulation of renin secretion and hypertension. However, the activity of the renin-angiotensin system also controls gap junction expression in the kidney. Treatment reducing angiotensin II activity, as used in hypertension treatment, can affect expression of renal and vascular gap junction.
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Affiliation(s)
| | - William A Cupples
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Canada
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30
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Alaaeddine RA, Mroueh A, Gust S, Eid AH, Plane F, El-Yazbi AF. Impaired cross-talk between NO and hyperpolarization in myoendothelial feedback: a novel therapeutic target in early endothelial dysfunction of metabolic disease. Curr Opin Pharmacol 2019; 45:33-41. [DOI: 10.1016/j.coph.2019.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/12/2019] [Accepted: 03/15/2019] [Indexed: 12/27/2022]
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31
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Novielli-Kuntz NM, Jelen M, Barr K, DeLalio LJ, Feng Q, Isakson BE, Gros R, Laird DW. Ablation of both Cx40 and Panx1 results in similar cardiovascular phenotypes exhibited in Cx40 knockout mice. Biosci Rep 2019; 39:BSR20182350. [PMID: 30745457 PMCID: PMC6393227 DOI: 10.1042/bsr20182350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/10/2019] [Accepted: 02/05/2019] [Indexed: 11/30/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are highly regulated large-pore channel-forming proteins that participate in cellular communication via small molecular exchange with the extracellular microenvironment, or in the case of connexins, directly between cells. Given the putative functional overlap between single membrane-spanning connexin hemichannels and Panx channels, and cardiovascular system prevalence, we generated the first Cx40-/-Panx1-/- mouse with the anticipation that this genetic modification would lead to a severe cardiovascular phenotype. Mice null for both Cx40 and Panx1 produced litter sizes and adult growth progression similar to wild-type (WT), Cx40-/- and Panx1-/- mice. Akin to Cx40-/- mice, Cx40-/-Panx1-/- mice exhibited cardiac hypertrophy and elevated systolic, diastolic, and mean arterial blood pressure compared with WT and Panx1-/- mice; however assessment of left ventricular ejection fraction and fractional shortening revealed no evidence of cardiac dysfunction between groups. Furthermore, Cx40-/-, Panx1-/-, and Cx40-/-Panx1-/- mice demonstrated impaired endothelial-mediated vasodilation of aortic segments to increasing concentrations of methacholine (MCh) compared with WT, highlighting roles for both Cx40 and Panx1 in vascular endothelial cell (EC) function. Surprisingly, elevated kidney renin mRNA expression, plasma renin activity, and extraglomerular renin-producing cell populations found in Cx40-/- mice was further exaggerated in double knockout mice. Thus, while gestation and gross development were conserved in Cx40-/-Panx1-/- mice, they exhibit cardiac hypertrophy, hypertension, and impaired endothelial-mediated vasodilation that phenocopies Cx40-/- mice. Nevertheless, the augmented renin homeostasis observed in the double knockout mice suggests that both Cx40 and Panx1 may play an integrative role.
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Affiliation(s)
| | - Meghan Jelen
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Qingping Feng
- Department of Physiology and Pharmacology London, ON, Canada
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Robert Gros
- Department of Physiology and Pharmacology London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology London, ON, Canada
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32
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Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
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Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
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Yin J, Lv L, Zhai P, Long T, Zhou Q, Pan H, Botwe G, Wang L, Wang Q, Tan L, Kuebler WM. Connexin 40 regulates lung endothelial permeability in acute lung injury via the ROCK1-MYPT1- MLC20 pathway. Am J Physiol Lung Cell Mol Physiol 2019; 316:L35-L44. [PMID: 30234377 DOI: 10.1152/ajplung.00012.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increased pulmonary vascular permeability is a hallmark of acute lung injury (ALI). Connexin 40 (Cx40) is a gap junctional protein abundantly present in the lung microvascular endothelium. Yet, the role of Cx40 in the regulation of lung vascular permeability and its underlying mechanisms are unclear. Here, we tested the hypothesis that Cx40 participates in regulation of lung endothelial permeability via a mechanism involving a Rho-associated protein kinase (ROCK) dependent regulation of myosin light chain (MLC). In murine models of intratracheal acid- or LPS-induced lung injury, genetic deficiency of Cx40 attenuated key features of ALI including vascular barrier failure. In human pulmonary microvascular endothelial cells (PMVECs), thrombin-induced loss of transendothelial electrical resistance was attenuated by a Cx40-inhibiting mimetic peptide (40GAP27), Cx40-specific shRNA, or ROCK inhibitor Y27632. In isolated perfused mouse lungs, platelet-activating factor-induced lung weight gain was abrogated by gap junction blocker carbenoxolone, 40GAP27, Y27632, or genetic deficiency of Cx40. Phosphorylation of MLC20 increased drastically in both LPS-treated PMVECs and HCl-treated mouse lungs. Expression of ROCK1 was increased in both LPS-treated PMVECs and HCl-treated mouse lungs, and paralleled by phosphorylation of MLC20. Coimmunoprecipitation experiments revealed protein-protein interaction between ROCK1 and Cx40. LPS-induced upregulation of ROCK1 and phosphorylation of MLC20 were blocked by knockdown of Cx40. LPS caused phosphorylation of myosin phosphatase targeting subunit 1, which could be abrogated by Y27632 or Cx40-shRNA. Our findings reveal a role of Cx40 in regulation of ROCK1 and MLC20 that contributes critically to lung vascular barrier failure in ALI.
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Affiliation(s)
- Jun Yin
- Department of Thoracic Surgery, Zhongshan Hospital of Fudan University , Shanghai , China
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Lu Lv
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Peng Zhai
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Tao Long
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Qiang Zhou
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Huiwen Pan
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Godwin Botwe
- Department of Cardiothoracic Surgery, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Liming Wang
- Department of Chemotherapy, Cancer Institute, Affiliated People's Hospital of Jiangsu University , Zhenjiang, Jiangsu , China
| | - Qun Wang
- Department of Thoracic Surgery, Zhongshan Hospital of Fudan University , Shanghai , China
| | - Lijie Tan
- Department of Thoracic Surgery, Zhongshan Hospital of Fudan University , Shanghai , China
| | - Wolfgang M Kuebler
- Department of Physiology and Center for Cardiovascular Research, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health , Berlin , Germany
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34
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Khalyfa A, Gozal D. Connexins and Atrial Fibrillation in Obstructive Sleep Apnea. CURRENT SLEEP MEDICINE REPORTS 2018; 4:300-311. [PMID: 31106116 PMCID: PMC6516763 DOI: 10.1007/s40675-018-0130-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF THE REVIEW To summarize the potential interactions between obstructive sleep apnea (OSA), atrial fibrillation (AF), and connexins. RECENT FINDINGS OSA is highly prevalent in patients with cardiovascular disease, and is associated with increased risk for end-organ substantial morbidities linked to autonomic nervous system imbalance, increased oxidative stress and inflammation, ultimately leading to reduced life expectancy. Epidemiological studies indicate that OSA is associated with increased incidence and progression of coronary heart disease, heart failure, stroke, as well as arrhythmias, particularly AF. Conversely, AF is very common among subjects referred for suspected OSA, and the prevalence of AF increases with OSA severity. The interrelationships between AF and OSA along with the well-known epidemiological links between these two conditions and obesity may reflect shared pathophysiological pathways, which may depend on the intercellular diffusion of signaling molecules into either the extracellular space or require cell-to-cell contact. Connexin signaling is accomplished via direct exchanges of cytosolic molecules between adjacent cells at gap membrane junctions for cell-to-cell coupling. The role of connexins in AF is now quite well established, but the impact of OSA on cardiac connexins has only recently begun to be investigated. Understanding the biology and regulatory mechanisms of connexins in OSA at the transcriptional, translational, and post-translational levels will undoubtedly require major efforts to decipher the breadth and complexity of connexin functions in OSA-induced AF. SUMMARY The risk of end-organ morbidities has initiated the search for circulating mechanistic biomarker signatures and the implementation of biomarker-based algorithms for precision-based diagnosis and risk assessment. Here we summarize recent findings in OSA as they relate to AF risk, and also review potential mechanisms linking OSA, AF and connexins.
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Affiliation(s)
- Abdelnaby Khalyfa
- Department of Pediatrics, Biological Sciences Division, Pritzker School of Medicine, The University of Chicago, Chicago IL 60637, USA
| | - David Gozal
- Department of Child Health, University of Missouri School of Medicine, Columbia, MO 65201, USA
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35
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Palao T, van Weert A, de Leeuw A, de Vos J, Bakker ENTP, van Bavel E. Sustained conduction of vasomotor responses in rat mesenteric arteries in a two-compartment in vitro set-up. Acta Physiol (Oxf) 2018; 224:e13099. [PMID: 29783282 PMCID: PMC6221078 DOI: 10.1111/apha.13099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 04/29/2018] [Accepted: 05/14/2018] [Indexed: 01/02/2023]
Abstract
Aim Conduction of vasomotor responses may contribute to long‐term regulation of resistance artery function and structure. Most previous studies have addressed conduction of vasoactivity only during very brief stimulations. We developed a novel set‐up that allows the local pharmacological stimulation of arteries in vitro for extended periods of time and studied the conduction of vasomotor responses in rat mesenteric arteries under those conditions. Methods The new in vitro set‐up was based on the pressure myograph. The superfusion chamber was divided halfway along the vessel into two compartments, allowing an independent superfusion of the arterial segment in each compartment. Local and remote cumulative concentration‐response curves were obtained for a range of vasoactive agents. Additional experiments were performed with the gap junction inhibitor 18β‐glycyrrhetinic acid and in absence of the endothelium. Results Phenylephrine‐induced constriction and acetylcholine‐induced dilation were conducted over a measured distance up to 2.84 mm, and this conduction was maintained for 5 minutes. Conduction of acetylcholine‐induced dilation was inhibited by 18β‐glycyrrhetinic acid, and conduction of phenylephrine‐induced constriction was abolished in absence of the endothelium. Constriction in response to high K+ was not conducted. Absence of remote stimulation dampened the local response to phenylephrine. Conclusion This study demonstrates maintained conduction of vasoactive responses to physiological agonists in rat mesenteric small arteries likely via gap junctions and endothelial cells, providing a possible mechanism for the sustained functional and structural control of arterial networks.
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Affiliation(s)
- T. Palao
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
| | - A. van Weert
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
| | - A. de Leeuw
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
| | - J. de Vos
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
| | - E. N. T. P. Bakker
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
| | - E. van Bavel
- Department of Biomedical Engineering and Physics; Academic Medical Center; Amsterdam the Netherlands
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36
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Rosenblum WI. Endothelium-dependent responses in the microcirculation observed in vivo. Acta Physiol (Oxf) 2018; 224:e13111. [PMID: 29873936 DOI: 10.1111/apha.13111] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/19/2018] [Accepted: 06/04/2018] [Indexed: 12/17/2022]
Abstract
Endothelium-dependent responses were first demonstrated 40 years ago in the aorta. Since then, extensive research has been conducted in vitro using conductance vessels and materials derived from them. However, the microcirculation controls blood flow to vital organs and has been the focus of in vivo studies of endothelium-dependent dilation beginning immediately after the first in vitro report. Initial in vivo studies employed a light/dye technique for selectively damaging the endothelium to unequivocally prove, in vivo, the existence of endothelium-dependent dilation and in the microvasculature. Endothelium-dependent constriction was similarly proven. Endothelium-dependent agonists include acetylcholine (ACh), bradykinin, arachidonic acid, calcium ionophore A-23187, calcitonin gene-related peptide (CGRP), serotonin, histamine and endothelin-1. Normal and disease states have been studied. Endothelial nitric oxide synthase, cyclooxygenase and cytochrome P450 have been shown to generate the mediators of the responses. Some of the key enzyme systems generate reactive oxygen species (ROS) like superoxide which may prevent EDR. However, one ROS, namely H2 O2 , is one of a number of hyperpolarizing factors that cause dilation initiated by endothelium. Depending upon microvascular bed, a single agonist may use different pathways to elicit an endothelium-dependent response. Interpretation of studies using inhibitors of eNOS is complicated by the fact that these inhibitors may also inhibit ATP-sensitive potassium channels. Other in vivo observations of brain arterioles failed to establish nitric oxide as the mediator of responses elicited by CGRP or by ACh and suggest that a nitrosothiol may be a better fit for the latter.
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Affiliation(s)
- W. I. Rosenblum
- Department of Pathology; Icahn School of Medicine at Mt Sinai NYC; New York NY USA
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37
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Patejdl R, Noack T. Calcium movement in smooth muscle and evaluation of graded functional intercellular coupling. CHAOS (WOODBURY, N.Y.) 2018; 28:106311. [PMID: 30384639 DOI: 10.1063/1.5035168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
Spontaneous activity of vascular smooth muscle is present in small arteries and some venous tissues like the hepatic portal vein. Whereas the ability to generate rhythmic membrane potential changes is expressed in a high number of primary oscillators, the generation of physiological tone and phasic activity requires synchronization of specialized pacemaker activity (Interstitial Cajal-like cells) by intercellular propagation and regeneration of excitation or a strong coupling mechanism of smooth muscle cells. The aim of this study was to deduce oscillator coupling by analyzing the spatiotemporal homogeneity of calcium oscillations within a native tissue preparation. Portal vein tissue was loaded with a calcium-sensitive dye (Fluo-3). By combining confocal microscopy and computation of spatial auto- and cross-correlation of the calcium signals, temporal and spatial coupling between cells was characterized. Spontaneous oscillations of calcium signals were measured at different predefined regions of interest. Cross-correlation analysis of these signals revealed that their damping was very similar in all directions of the investigated z-plane. In single experiments, improved cell-to-cell coupling was seen when noradrenaline (1-10 μM) was added to the bath-solution. With the chosen parameters of frame refresh, the velocity of signal propagation was faster than the maximum detectable velocity, but it could be estimated to exceed 0.1 mm/s. Correlative Network Analysis is a new and very useful tool to determine the functional coupling parameters of quasi-homogenous biological networks and their temporal changes. The action and significance of pharmacological modulators can be well studied on cellular and functional aspects with this newly introduced technique in biological sciences.
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Affiliation(s)
- R Patejdl
- Department of Physiology, University of Rostock, Universitätsmedizin, Oscar-Langendorff Institut für Physiologie, Gertrudenstr. 9, D-18057 Rostock, Germany
| | - T Noack
- Department of Physiology, University of Rostock, Universitätsmedizin, Oscar-Langendorff Institut für Physiologie, Gertrudenstr. 9, D-18057 Rostock, Germany
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38
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Castorena-Gonzalez JA, Zawieja SD, Li M, Srinivasan RS, Simon AM, de Wit C, de la Torre R, Martinez-Lemus LA, Hennig GW, Davis MJ. Mechanisms of Connexin-Related Lymphedema. Circ Res 2018; 123:964-985. [PMID: 30355030 PMCID: PMC6771293 DOI: 10.1161/circresaha.117.312576] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
RATIONALE Mutations in GJC2 and GJA1, encoding Cxs (connexins) 47 and 43, respectively, are linked to lymphedema, but the underlying mechanisms are unknown. Because efficient lymph transport relies on the coordinated contractions of lymphatic muscle cells (LMCs) and their electrical coupling through Cxs, Cx-related lymphedema is proposed to result from dyssynchronous contractions of lymphatic vessels. OBJECTIVE To determine which Cx isoforms in LMCs and lymphatic endothelial cells are required for the entrainment of lymphatic contraction waves and efficient lymph transport. METHODS AND RESULTS We developed novel methods to quantify the spatiotemporal entrainment of lymphatic contraction waves and used optogenetic techniques to analyze calcium signaling within and between the LMC and the lymphatic endothelial cell layers. Genetic deletion of the major lymphatic endothelial cell Cxs (Cx43, Cx47, or Cx37) revealed that none were necessary for the synchronization of the global calcium events that triggered propagating contraction waves. We identified Cx45 in human and mouse LMCs as the critical Cx mediating the conduction of pacemaking signals and entrained contractions. Smooth muscle-specific Cx45 deficiency resulted in 10- to 18-fold reduction in conduction speed, partial-to-severe loss of contractile coordination, and impaired lymph pump function ex vivo and in vivo. Cx45 deficiency resulted in profound inhibition of lymph transport in vivo, but only under an imposed gravitational load. CONCLUSIONS Our results (1) identify Cx45 as the Cx isoform mediating the entrainment of the contraction waves in LMCs; (2) show that major endothelial Cxs are dispensable for the entrainment of contractions; (3) reveal a lack of coupling between lymphatic endothelial cells and LMCs, in contrast to arterioles; (4) point to lymphatic valve defects, rather than contraction dyssynchrony, as the mechanism underlying GJC2- or GJA1-related lymphedema; and (5) show that a gravitational load exacerbates lymphatic contractile defects in the intact mouse hindlimb, which is likely critical for the development of lymphedema in the adult mouse.
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Affiliation(s)
| | - Scott D. Zawieja
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | - Min Li
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | - R. Sathish Srinivasan
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City OK
| | | | - Cor de Wit
- Institute of Physiology, University of Luebeck, Luebeck Germany
| | | | - Luis A. Martinez-Lemus
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
| | | | - Michael J. Davis
- Dept. of Medical Pharmacology and Physiology and University of Missouri School of Medicine
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39
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Molica F, Figueroa XF, Kwak BR, Isakson BE, Gibbins JM. Connexins and Pannexins in Vascular Function and Disease. Int J Mol Sci 2018; 19:ijms19061663. [PMID: 29874791 PMCID: PMC6032213 DOI: 10.3390/ijms19061663] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 12/24/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are ubiquitous membrane channel forming proteins that are critically involved in many aspects of vascular physiology and pathology. The permeation of ions and small metabolites through Panx channels, Cx hemichannels and gap junction channels confers a crucial role to these proteins in intercellular communication and in maintaining tissue homeostasis. This review provides an overview of current knowledge with respect to the pathophysiological role of these channels in large arteries, the microcirculation, veins, the lymphatic system and platelet function. The essential nature of these membrane proteins in vascular homeostasis is further emphasized by the pathologies that are linked to mutations and polymorphisms in Cx and Panx genes.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Xavier F Figueroa
- Departamento de Fisiología, Faculdad de Ciencias Biológicas, Pontifica Universidad Católica de Chile, Santiago 8330025, Chile.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
| | - Jonathan M Gibbins
- Institute for Cardiovascular & Metabolic Research, School of Biological Sciences, Harborne Building, University of Reading, Reading RG6 6AS, UK.
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40
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Park SK, Herrnreiter A, Pfister SL, Gauthier KM, Falck BA, Falck JR, Campbell WB. GPR40 is a low-affinity epoxyeicosatrienoic acid receptor in vascular cells. J Biol Chem 2018; 293:10675-10691. [PMID: 29777058 DOI: 10.1074/jbc.ra117.001297] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/25/2018] [Indexed: 12/17/2022] Open
Abstract
Endothelium-derived epoxyeicosatrienoic acids (EETs) have numerous vascular activities mediated by G protein-coupled receptors. Long-chain free fatty acids and EETs activate GPR40, prompting us to investigate the role of GPR40 in some vascular EET activities. 14,15-EET, 11,12-EET, arachidonic acid, and the GPR40 agonist GW9508 increase intracellular calcium concentrations in human GPR40-overexpressing HEK293 cells (EC50 = 0.58 ± 0.08 μm, 0.91 ± 0.08 μm, 3.9 ± 0.06 μm, and 19 ± 0.37 nm, respectively). EETs with cis- and trans-epoxides had similar activities, whereas substitution of a thiirane sulfur for the epoxide oxygen decreased the activities. 8,9-EET, 5,6-EET, and the epoxide hydrolysis products 11,12- and 14,15-dihydroxyeicosatrienoic acids were less active than 11,12-EET. The GPR40 antagonist GW1100 and siRNA-mediated GPR40 silencing blocked the EET- and GW9508-induced calcium increases. EETs are weak GPR120 agonists. GPR40 expression was detected in human and bovine endothelial cells (ECs), smooth muscle cells, and arteries. 11,12-EET concentration-dependently relaxed preconstricted coronary arteries; however, these relaxations were not altered by GW1100. In human ECs, 11,12-EET increased MAP kinase (MAPK)-mediated ERK phosphorylation, phosphorylation and levels of connexin-43 (Cx43), and expression of cyclooxygenase-2 (COX-2), all of which were inhibited by GW1100 and the MAPK inhibitor U0126. Moreover, siRNA-mediated GPR40 silencing decreased 11,12-EET-induced ERK phosphorylation. These results indicated that GPR40 is a low-affinity EET receptor in vascular cells and arteries. We conclude that epoxidation of arachidonic acid to EETs enhances GPR40 agonist activity and that 11,12-EET stimulation of GPR40 increases Cx43 and COX-2 expression in ECs via ERK phosphorylation.
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Affiliation(s)
- Sang-Kyu Park
- From the Department of Pharmacology and Toxicology Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and
| | - Anja Herrnreiter
- From the Department of Pharmacology and Toxicology Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and
| | - Sandra L Pfister
- From the Department of Pharmacology and Toxicology Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and
| | - Kathryn M Gauthier
- From the Department of Pharmacology and Toxicology Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and
| | - Benjamin A Falck
- the Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - John R Falck
- the Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - William B Campbell
- From the Department of Pharmacology and Toxicology Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and
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41
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Mishra JS, More AS, Hankins GDV, Kumar S. Hyperandrogenemia reduces endothelium-derived hyperpolarizing factor-mediated relaxation in mesenteric artery of female rats. Biol Reprod 2018; 96:1221-1230. [PMID: 28486649 DOI: 10.1093/biolre/iox043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/08/2017] [Indexed: 01/05/2023] Open
Abstract
Women with polycystic ovary syndrome (PCOS) are often presented with hyperandrogenemia along with vascular dysfunction and elevated blood pressure. In animal models of PCOS, anti-androgen treatment decreased blood pressure, indicating a key role for androgens in the development of hypertension. However, the underlying androgen-mediated mechanism that contributes to increased blood pressure is not known. This study determined whether elevated androgens affect endothelium-derived hyperpolarizing factor (EDHF)-mediated vascular relaxation responses through alteration in function of gap junctional proteins. Female rats were implanted with placebo or dihydrotestosterone (DHT) pellets (7.5 mg, 90-day release). After 12 weeks of DHT exposure, blood pressure was assessed through carotid arterial catheter and endothelium-dependent mesenteric arterial EDHF relaxation using wire myograph. Connexin expression in mesenteric arteries was also examined. Elevated DHT significantly increased mean arterial pressure and decreased endothelium-dependent EDHF-mediated acetylcholine relaxation. Inhibition of Cx40 did not have any effect, while inhibition of Cx37 decreased EDHF relaxation to a similar magnitude in both controls and DHT females. On the other hand, inhibition of Cx43 significantly attenuated EDHF relaxation in mesenteric arteries of controls but not DHT females. Elevated DHT did not alter Cx37 or Cx40, but decreased Cx43 mRNA and protein levels in mesenteric arteries. In vitro exposure of DHT to cultured mesenteric artery smooth muscle cells dose-dependently downregulated Cx43 expression. In conclusion, increased blood pressure in hyperandrogenic females is due, at least in part, to decreased EDHF-mediated vascular relaxation responses. Decreased Cx43 expression and activity may play a role in contributing to androgen-induced decrease in EDHF function.
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Affiliation(s)
- Jay S Mishra
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston, Texas, USA
| | - Amar S More
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston, Texas, USA
| | - Gary D V Hankins
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston, Texas, USA
| | - Sathish Kumar
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Medical Branch at Galveston, Texas, USA
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42
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Dora KA. Endothelial-smooth muscle cell interactions in the regulation of vascular tone in skeletal muscle. Microcirculation 2018; 23:626-630. [PMID: 27653241 DOI: 10.1111/micc.12322] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/19/2016] [Indexed: 11/28/2022]
Abstract
The SMCs of skeletal muscle arterioles are intricately sensitive to changes in membrane potential. Upon increasing luminal pressure, the SMCs depolarize, thereby opening VDCCs, which leads to contraction. Mechanisms that oppose this myogenic tone can involve voltage-dependent and independent dilator pathways, and can be endothelium-dependent or independent. Of particular interest are the pathways leading to hyperpolarization of SMCs, as these can potentially evoke both local and conducted dilation. This review focuses on three agonists that cause local and conducted dilation in skeletal muscle: ACh, ATP, and KCl. The mechanisms for the release of these agonists during motor nerve stimulation and/or hypoxia, and their actions to open either Ca2+ -activated K+ channels (KCa ) or inwardly rectifying K+ channels (KIR ) are described. By causing local and conducted dilation, each agonist has the ability to improve skeletal muscle blood flow during exercise and ischemia.
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Affiliation(s)
- Kim A Dora
- Department of Pharmacology, University of Oxford, Oxford, UK
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43
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Zhou HS, Li M, Sui BD, Wei L, Hou R, Chen WS, Li Q, Bi SH, Zhang JZ, Yi DH. Lipopolysaccharide impairs permeability of pulmonary microvascular endothelial cells via Connexin40. Microvasc Res 2018; 115:58-67. [PMID: 28870649 DOI: 10.1016/j.mvr.2017.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/25/2017] [Accepted: 08/30/2017] [Indexed: 12/27/2022]
Abstract
The endotoxin lipopolysaccharide (LPS)-induced pulmonary endothelial barrier disruption is a key pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the molecular mechanisms underlying LPS-impaired permeability of pulmonary microvascular endothelial cells (PMVECs) are not fully understood. Gap junctions, particularly Connexin40 (Cx40), are necessary for the maintenance of normal vascular function. In this study, we for the first time investigated the role of Cx40 in LPS-impaired permeability of PMVECs and provided potential therapeutic approaches based on mechanistic findings of Cx40 regulation by LPS stimuli. Rat PMVECs were isolated, cultured and identified with cell morphology, specific markers, ultrastructural characteristics and functional tests. Western blot analysis demonstrated that Cx40 is the major connexin highly expressed in PMVECs. Furthermore, by inhibiting Cx40 in a time-dependent manner, LPS impaired gap junction function and induced permeability injury of PMVECs. The key role of Cx40 decline in mediating detrimental effects of LPS was further confirmed in rescue experiments through Cx40 overexpression. Mechanistically, LPS stress on PMVECs inhibited the protein kinase C (PKC) pathway, which may synergize with the inflammatory nuclear factor kappaB (NFκB) signaling activation in suppressing Cx40 expression level and phosphorylation. Moreover, through pharmacological PKC activation or NFκB inhibition, Cx40 activity in PMVECs could be restored, leading to maintained barrier function under LPS stress. Our findings uncover a previously unrecognized role of Cx40 and its regulatory mechanisms in impaired endothelial integrity under endotoxin and inflammation, shedding light on intervention approaches to improve pulmonary endothelial barrier function in ALI and ARDS.
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Affiliation(s)
- Hua-Song Zhou
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Meng Li
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Bing-Dong Sui
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA 19104, USA
| | - Lei Wei
- Xi'an Satellite Control Centre Clinic, Xi'an, Shaanxi 710043, China
| | - Rui Hou
- State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Wen-Sheng Chen
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Qiang Li
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Sheng-Hui Bi
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jin-Zhou Zhang
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| | - Ding-Hua Yi
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
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44
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Abstract
Hypoxic pulmonary vasoconstriction (HPV) in combination with hypercapnic pulmonary vasoconstriction redistributes pulmonary blood flow from poorly aerated to better ventilated lung regions by an active process of local vasoconstriction. Impairment of HPV results in ventilation-perfusion mismatch and is commonly associated with various lung diseases including pneumonia, sepsis, or cystic fibrosis. Although several regulatory pathways have been identified, considerable knowledge gaps persist, and a unifying concept of the signaling pathways that underlie HPV and their impairment in lung diseases has not yet emerged. In the past, conceptual models of HPV have focused on pulmonary arterial smooth muscle cells (PASMC) acting as sensor and effector of hypoxia in the pulmonary vasculature. In contrast, the endothelium was considered a modulating bystander in this scenario. For an ideal design, however, the oxygen sensor in HPV should be located in the region of gas exchange, i.e., in the alveolar capillary network. This concept requires the retrograde propagation of the hypoxic signal along the endothelial layer of the vascular wall and subsequent contraction of PASMC in upstream arterioles that is elicited via temporospatially tightly controlled endothelial-smooth muscle cell crosstalk. The present review summarizes recent work that provides proof-of-principle for the existence and functional relevance of such signaling pathway in HPV that involves important roles for connexin 40, epoxyeicosatrienoic acids, sphingolipids, and cystic fibrosis transmembrane conductance regulator. Of translational relevance, implication of these molecules provides for novel mechanistic explanations for impaired ventilation/perfusion matching in patients with pneumonia, sepsis, cystic fibrosis, and presumably various other lung diseases.
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Affiliation(s)
- Benjamin Grimmer
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Ontario , Canada
- Departments of Surgery and Physiology, University of Toronto , Toronto, Ontario , Canada
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45
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Welsh DG, Tran CHT, Hald BO, Sancho M. The Conducted Vasomotor Response: Function, Biophysical Basis, and Pharmacological Control. Annu Rev Pharmacol Toxicol 2017; 58:391-410. [PMID: 28968190 DOI: 10.1146/annurev-pharmtox-010617-052623] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Arterial tone is coordinated among vessel segments to optimize nutrient transport and organ function. Coordinated vasomotor activity is remarkable to observe and depends on stimuli, sparsely generated in tissue, eliciting electrical responses that conduct lengthwise among electrically coupled vascular cells. The conducted response is the focus of this topical review, and in this regard, the authors highlight literature that advances an appreciation of functional significance, cellular mechanisms, and biophysical principles. Of particular note, this review stresses that conduction is enabled by a defined pattern of charge movement along the arterial wall as set by three key parameters (tissue structure, gap junctional resistivity, and ion channel activity). The impact of disease on conduction is carefully discussed, as are potential strategies to restore this key biological response and, along with it, the match of blood flow delivery with tissue energetic demand.
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Affiliation(s)
- Donald G Welsh
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine, University of Western Ontario, London, Ontario N6A 5B7, Canada;
| | - Cam Ha T Tran
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Bjorn O Hald
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Maria Sancho
- Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine, University of Western Ontario, London, Ontario N6A 5B7, Canada;
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46
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Guo R, Si R, Scott BT, Makino A. Mitochondrial connexin40 regulates mitochondrial calcium uptake in coronary endothelial cells. Am J Physiol Cell Physiol 2017; 312:C398-C406. [PMID: 28122731 PMCID: PMC5407023 DOI: 10.1152/ajpcell.00283.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 01/30/2023]
Abstract
Connexins (Cxs) are a group of integral membrane proteins that can form gap junctions between adjacent cells. Recently, it was reported that Cx43 is expressed not only in the plasma membrane but also in the inner mitochondrial membrane and that it regulates mitochondrial functions. Cx40 is predominantly expressed in vascular endothelial cells (ECs) and plays an important role in the electrical propagation between ECs and endothelial/smooth muscle cells. However, it is unknown whether Cx40 is expressed in the mitochondria and what the role of mitochondrial Cx40 is in endothelial functions. We observed in coronary ECs that Cx40 protein was expressed in the mitochondria, as determined by Western blot and immunofluorescence studies. We found that mouse coronary ECs (MCECs) isolated from Cx40 knockout (Cx40 KO) mice exhibited significantly lower resting mitochondrial calcium concentration ([Ca2+]mito) than MCECs from wild-type (WT) mice. After increase in cytosolic Ca2+ concentration ([Ca2+]cyto) with cyclopiazonic acid, calcium uptake into the mitochondria was significantly attenuated in MCECs from Cx40 KO mice compared with WT MCECs. There was no difference in resting [Ca2+]cyto and store-operated calcium entry in MCECs from WT and Cx40 KO mice. We also detected a significant decrease in the concentration of mitochondrial reactive oxygen species (ROS) in Cx40 KO MCECs. Cx40 overexpression in ECs significantly increased resting [Ca2+]mito level and calcium uptake by mitochondria in response to increased [Ca2+]cyto and augmented mitochondrial ROS production. These data suggest that mitochondrial Cx40 contributes to the regulation of mitochondrial calcium homeostasis.
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Affiliation(s)
- Rui Guo
- Department of Physiology, The University of Arizona, Tucson, Arizona; and
| | - Rui Si
- Department of Physiology, The University of Arizona, Tucson, Arizona; and
| | - Brian T Scott
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Ayako Makino
- Department of Physiology, The University of Arizona, Tucson, Arizona; and
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Meda P. Gap junction proteins are key drivers of endocrine function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:124-140. [PMID: 28284720 DOI: 10.1016/j.bbamem.2017.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 01/07/2023]
Abstract
It has long been known that the main secretory cells of exocrine and endocrine glands are connected by gap junctions, made by a variety of connexin species that ensure their electrical and metabolic coupling. Experiments in culture systems and animal models have since provided increasing evidence that connexin signaling contributes to control the biosynthesis and release of secretory products, as well as to the life and death of secretory cells. More recently, genetic studies have further provided the first lines of evidence that connexins also control the function of human glands, which are central to the pathogenesis of major endocrine diseases. Here, we summarize the recent information gathered on connexin signaling in these systems, since the last reviews on the topic, with particular regard to the pancreatic beta cells which produce insulin, and the renal cells which produce renin. These cells are keys to the development of various forms of diabetes and hypertension, respectively, and combine to account for the exploding, worldwide prevalence of the metabolic syndrome. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva Medical School, Switzerland.
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Garland CJ, Dora KA. EDH: endothelium-dependent hyperpolarization and microvascular signalling. Acta Physiol (Oxf) 2017; 219:152-161. [PMID: 26752699 DOI: 10.1111/apha.12649] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/04/2015] [Accepted: 01/06/2016] [Indexed: 12/31/2022]
Abstract
Endothelium-dependent hyperpolarizing factor (EDHF) is a powerful vasodilator influence in small resistance arteries and thus an important modulator of blood pressure and flow. As the name suggests, EDHF was thought to describe a diffusible factor stimulating smooth muscle hyperpolarization (and thus vasodilatation). However, this idea has evolved with the recognition that a factor can operate alongside the spread of hyperpolarizing current from the endothelium to the vascular smooth muscle (VSM). As such, the pathway is now termed endothelium-dependent hyperpolarization (EDH). EDH is activated by an increase in endothelial [Ca2+ ]i , which stimulates two Ca2+ -sensitive K channels, SKCa and IKCa . This was discovered because apamin and charybdotoxin applied in combination blocked EDHF responses, but iberiotoxin - a blocker of BKCa - was not able to substitute for charybdotoxin. SKCa and IKCa channels are arranged in endothelial microdomains, particularly within projections towards the adjacent smooth muscle, which are rich in IKCa channels and close to interendothelial gap junctions where SKCa channels, are prevalent. KCa activation hyperpolarizes endothelial cells, and K+ efflux through them can act as a diffusible 'EDHF' by stimulating VSM Na+ ,K+ -ATPase and inwardly rectifying K channels (KIR ). In parallel, hyperpolarizing current spreads from the endothelium to the smooth muscle through myoendothelial gap junctions located on endothelial projections. The resulting radial EDH is complemented by the spread of 'conducted' hyperpolarization along the endothelium of arteries and arterioles to affect conducted vasodilatation (CVD). Retrograde CVD effectively integrates blood flow within the microcirculation, but how the underlying hyperpolarization is sustained is unclear.
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Affiliation(s)
- C. J. Garland
- Department of Pharmacology; University of Oxford; Oxford UK
| | - K. A. Dora
- Department of Pharmacology; University of Oxford; Oxford UK
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Dora KA. Conducted dilatation to ATP and K + in rat skeletal muscle arterioles. Acta Physiol (Oxf) 2017; 219:202-218. [PMID: 26804547 PMCID: PMC5215486 DOI: 10.1111/apha.12656] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/25/2015] [Accepted: 01/19/2016] [Indexed: 11/28/2022]
Abstract
AIM During exercise in humans, circulating levels of ATP and K+ increase at a time when blood flow increases to satisfy metabolic demand. Both molecules can activate arteriolar K+ channels to stimulate vasodilatation; here, it is established whether conducted dilatation is observed in a skeletal muscle bed. METHODS Isolated and cannulated rat cremaster arterioles were used to assess both local and conducted responses. Agents were either added to the bath, focally pulse-ejected to the downstream end of arterioles, or in triple-cannulated arterioles, luminally perfused into the downstream branches to assess both local and conducted responses. RESULTS The endothelium-dependent agonist ACh and the KATP channel opener levcromakalim each stimulated both local and conducted vasodilatation. Focal, bolus delivery of ATP (10 μm) or KCl (33 mm) to the outside of arterioles stimulated a biphasic vasomotor response: rapid vasoconstriction followed by dilatation as each washed away. At lower concentrations of KCl (19 mm), constriction was avoided, and instead, Ba2+ -sensitive local dilatation and conducted dilatation were both observed. Luminal perfusion of ATP avoided constriction and activated P2Y1 receptors stimulating vasodilatation secondary to opening of KCa channels. In triple-cannulated arterioles, either ATP (10 μm) or K+ (15 mm) luminally perfused into daughter branches of a bifurcation stimulated local dilatation which conducted into the parent arteriole. CONCLUSION The recognized physiological autocrine and paracrine mediators ATP and K+ each act to evoke both local and conducted vasodilatation in rat cremaster arterioles. Therefore, in situations when circulating levels are raised, such as during exercise, these agents can act as important regulators of blood flow.
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Affiliation(s)
- K. A. Dora
- Department of PharmacologyUniversity of OxfordOxfordUK
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Wang LJ, Liu WD, Zhang L, Ma KT, Zhao L, Shi WY, Zhang WW, Wang YZ, Li L, Si JQ. Enhanced expression of Cx43 and gap junction communication in vascular smooth muscle cells of spontaneously hypertensive rats. Mol Med Rep 2016; 14:4083-4090. [PMID: 27748857 PMCID: PMC5101886 DOI: 10.3892/mmr.2016.5783] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 08/30/2016] [Indexed: 11/24/2022] Open
Abstract
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole-cell patch clamp recording demonstrated that NFA at 1×10–4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9.73 to 0.48 ms (P<0.05; n=6). Pressure myograph measurement showed that NFA at 3×10-4 M fully neutralized the contraction caused by phenylephrine. The relaxation responses of normotensive control Wistar Kyoto (WKY) rats were significantly higher, compared with those of the SHRs (P<0.05; n=6). Western blot and reverse transcription-quantitative polymerase chain reaction analyses showed that the mRNA and protein expression levels of Cx43 of the third-level branch of mesenteric arterioles of the SHRs and WKY rats were higher, compared with those of the first-level branch. The mRNA and protein expression levels of Cx43 of the primary and third-level branches of the mesenteric arterioles in the SHRs were higher, compared with those in the WKY rats (P<0.05; n=6). The mRNA levels of Cx43 in the mesenteric arterioles were significantly downregulated by NFA in a concentration-dependent manner (P<0.01; n=6). The protein levels of Cx43 in primary cultured VSMCs isolated from the mesenteric arterioles were also significantly downregulated by NFA in a concentration-dependent manner (P<0.01; n=6). These results showed that the vasorelaxatory effects of GJ inhibitors were reduced in the SHRs, which was associated with a higher protein expression level of Cx43 in the mesenteric arterioles of the SHRs. NFA also relaxed the mesenteric arterioles by reducing the expression of Cx43, which decreased blood pressure. Therefore, regulation of the expression of GJs may be a therapeutic target for the treatment of hypertension.
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Affiliation(s)
- Li-Jie Wang
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Wei-Dong Liu
- Department of Gastroenterology, The People's Hospital of Xinjiang Uyghur Autonomous Region, Urumqi, Xinjiang 830001, P.R. China
| | - Liang Zhang
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Ke-Tao Ma
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Lei Zhao
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Wen-Yan Shi
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Wen-Wen Zhang
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Ying-Zi Wang
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Li Li
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
| | - Jun-Qiang Si
- Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China
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