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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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2
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Sedovy MW, Leng X, Leaf MR, Iqbal F, Payne LB, Chappell JC, Johnstone SR. Connexin 43 across the Vasculature: Gap Junctions and Beyond. J Vasc Res 2022; 60:101-113. [PMID: 36513042 PMCID: PMC11073551 DOI: 10.1159/000527469] [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: 05/25/2022] [Accepted: 09/26/2022] [Indexed: 12/15/2022] Open
Abstract
Connexin 43 (Cx43) is essential to the function of the vasculature. Cx43 proteins form gap junctions that allow for the exchange of ions and molecules between vascular cells to facilitate cell-to-cell signaling and coordinate vasomotor activity. Cx43 also has intracellular signaling functions that influence vascular cell proliferation and migration. Cx43 is expressed in all vascular cell types, although its expression and function vary by vessel size and location. This includes expression in vascular smooth muscle cells (vSMC), endothelial cells (EC), and pericytes. Cx43 is thought to coordinate homocellular signaling within EC and vSMC. Cx43 gap junctions also function as conduits between different cell types (heterocellular signaling), between EC and vSMC at the myoendothelial junction, and between pericyte and EC in capillaries. Alterations in Cx43 expression, localization, and post-translational modification have been identified in vascular disease states, including atherosclerosis, hypertension, and diabetes. In this review, we discuss the current understanding of Cx43 localization and function in healthy and diseased blood vessels across all vascular beds.
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Affiliation(s)
- Meghan W. Sedovy
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
- Translational Biology, Medicine, And Health Graduate Program, Virginia Tech, Blacksburg, VA, USA
| | - Xinyan Leng
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
| | - Melissa R. Leaf
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Farwah Iqbal
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Laura Beth Payne
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
| | - John C. Chappell
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
| | - Scott R. Johnstone
- The Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, 4 Riverside Circle, Roanoke, VA, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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3
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Burboa PC, Puebla M, Gaete PS, Durán WN, Lillo MA. Connexin and Pannexin Large-Pore Channels in Microcirculation and Neurovascular Coupling Function. Int J Mol Sci 2022; 23:ijms23137303. [PMID: 35806312 PMCID: PMC9266979 DOI: 10.3390/ijms23137303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Microcirculation homeostasis depends on several channels permeable to ions and/or small molecules that facilitate the regulation of the vasomotor tone, hyperpermeability, the blood–brain barrier, and the neurovascular coupling function. Connexin (Cxs) and Pannexin (Panxs) large-pore channel proteins are implicated in several aspects of vascular physiology. The permeation of ions (i.e., Ca2+) and key metabolites (ATP, prostaglandins, D-serine, etc.) through Cxs (i.e., gap junction channels or hemichannels) and Panxs proteins plays a vital role in intercellular communication and maintaining vascular homeostasis. Therefore, dysregulation or genetic pathologies associated with these channels promote deleterious tissue consequences. This review provides an overview of current knowledge concerning the physiological role of these large-pore molecule channels in microcirculation (arterioles, capillaries, venules) and in the neurovascular coupling function.
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Affiliation(s)
- Pía C. Burboa
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Mariela Puebla
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California at Davis, Davis, CA 95616, USA;
| | - Walter N. Durán
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Rutgers School of Graduate Studies, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Mauricio A. Lillo
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Correspondence:
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4
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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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5
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Si R, Cabrera JTO, Tsuji-Hosokawa A, Guo R, Watanabe M, Gao L, Lee YS, Moon JS, Scott BT, Wang J, Ashton AW, Rao JN, Wang JY, Yuan JXJ, Makino A. HuR/Cx40 downregulation causes coronary microvascular dysfunction in type 2 diabetes. JCI Insight 2021; 6:147982. [PMID: 34747371 PMCID: PMC8663561 DOI: 10.1172/jci.insight.147982] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/29/2021] [Indexed: 11/30/2022] Open
Abstract
Patients with diabetes with coronary microvascular disease (CMD) exhibit higher cardiac mortality than patients without CMD. However, the molecular mechanism by which diabetes promotes CMD is poorly understood. RNA-binding protein human antigen R (HuR) is a key regulator of mRNA stability and translation; therefore, we investigated the role of HuR in the development of CMD in mice with type 2 diabetes. Diabetic mice exhibited decreases in coronary flow velocity reserve (CFVR; a determinant of coronary microvascular function) and capillary density in the left ventricle. HuR levels in cardiac endothelial cells (CECs) were significantly lower in diabetic mice and patients with diabetes than the controls. Endothelial-specific HuR-KO mice also displayed significant reductions in CFVR and capillary density. By examining mRNA levels of 92 genes associated with endothelial function, we found that HuR, Cx40, and Nox4 levels were decreased in CECs from diabetic and HuR-KO mice compared with control mice. Cx40 expression and HuR binding to Cx40 mRNA were downregulated in CECs from diabetic mice. Cx40-KO mice exhibited decreased CFVR and capillary density, whereas endothelium-specific Cx40 overexpression increased capillary density and improved CFVR in diabetic mice. These data suggest that decreased HuR contributes to the development of CMD in diabetes through downregulation of gap junction protein Cx40 in CECs.
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Affiliation(s)
- Rui Si
- Department of Physiology, The University of Arizona (UA), Tucson, Arizona, USA.,Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Shaanxi, China
| | | | | | - Rui Guo
- Department of Physiology, The University of Arizona (UA), Tucson, Arizona, USA
| | - Makiko Watanabe
- Department of Physiology, The University of Arizona (UA), Tucson, Arizona, USA
| | - Lei Gao
- Department of Medicine, UCSD, La Jolla, California, USA
| | - Yun Sok Lee
- Department of Medicine, UCSD, La Jolla, California, USA
| | - Jae-Su Moon
- Department of Medicine, UCSD, La Jolla, California, USA
| | - Brian T Scott
- Department of Medicine, UCSD, La Jolla, California, USA
| | - Jian Wang
- Department of Physiology, The University of Arizona (UA), Tucson, Arizona, USA.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Anthony W Ashton
- Division of Perinatal Research, Kolling Institute of Medical Research, University of Sydney, New South Wales, Australia
| | - Jaladanki N Rao
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jian-Ying Wang
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Ayako Makino
- Department of Physiology, The University of Arizona (UA), Tucson, Arizona, USA.,Department of Medicine, UCSD, La Jolla, California, USA
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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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7
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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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Hald BO, Welsh DG. Conceptualizing conduction as a pliant electrical response: impact of gap junctions and ion channels. Am J Physiol Heart Circ Physiol 2020; 319:H1276-H1289. [PMID: 32986968 DOI: 10.1152/ajpheart.00285.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Vasomotor responses conduct among resistance arteries to coordinate blood flow delivery pursuant to energetic demand. Conduction is set by the electrical and mechanical properties of vascular cells, the former tied to how gap junctions and ion channels distribute and dissipate charge, respectively. These membrane proteins are subject to modulation; thus, conduction could be viewed as "pliant" to the current regulatory state. This study used in silico approaches to conceptualize electrical pliancy and to illustrate how gap junctional and ion channel properties distinctly impact conduction along a single skeletal muscle artery or a branching cerebrovascular network. Initial simulations revealed how vascular cells encoded with electrotonic properties best reproduced spreading behavior; the endothelium's importance as a charge source and a longitudinal conduit was readily observed. Alterations in gap junctional conductance produced unique electrical fingerprints: 1) decreased endothelial coupling impaired longitudinal but enhanced radial spread, and 2) reduced myoendothelial coupling limited radial but enhanced longitudinal spread. Subsequent simulations illustrated how tuning ion channel activity, e.g., inward rectifying- and voltage-gated K+ channels, modified charge dissipation, resting membrane potential, and the spread of the electrical phenomenon. Restricting ion channel tuning to a network subregion then revealed how electrical spread could be locally shaped in accordance with the aggregate changes in membrane resistance. In summary, our analysis frames and reimagines electrical conduction as a pliable process, with subtle regulatory changes to membrane proteins shaping network spread and tissue perfusion.NEW & NOTEWORTHY Conducted vasomotor responses depend on initiation and spread of electrical phenomena along arterial walls and their translation into contractile responses. Using computational approaches, we show how subtle but widespread regulation of gap junctions and ion channels can modulate the range and amplitude of electrical spread. Ion channels are regulated by endocrine and mechanical signals and may differ regionally in networks. Subregional electrical changes are not spatially confined but may affect electrical conduction in neighboring regions.
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Affiliation(s)
- Bjørn Olav Hald
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Donald G Welsh
- Robarts Research Institute and Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
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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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10
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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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11
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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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12
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Zhang Q, Tsuji-Hosokawa A, Willson C, Watanabe M, Si R, Lai N, Wang Z, Yuan JXJ, Wang J, Makino A. Chloroquine differentially modulates coronary vasodilation in control and diabetic mice. Br J Pharmacol 2020; 177:314-327. [PMID: 31503328 DOI: 10.1111/bph.14864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE Chloroquine is a traditional medicine to treat malaria. There is increasing evidence that chloroquine not only induces phagocytosis but regulates vascular tone. Few reports investigating the effect of chloroquine on vascular responsiveness of coronary arteries have been made. In this study, we examined how chloroquine affected endothelium-dependent relaxation in coronary arteries under normal and diabetic conditions. EXPERIMENTAL APPROACH We isolated coronary arteries from mice and examined endothelium-dependent relaxation (EDR). Human coronary endothelial cells and mouse coronary endothelial cells isolated from control and diabetic mouse (TALLYHO/Jng [TH] mice, a spontaneous type 2 diabetic mouse model) were used for the molecular biological or cytosolic NO and Ca2+ measurements. KEY RESULTS Chloroquine inhibited endothelium-derived NO-dependent relaxation but had negligible effect on endothelium-derived hyperpolarization (EDH)-dependent relaxation in coronary arteries of control mice. Chloroquine significantly decreased NO production in control human coronary endothelial cells partly by phosphorylating eNOSThr495 (an inhibitory phosphorylation site of eNOS) and attenuating the rise of cytosolic Ca2+ concentration after stimulation. EDR was significantly inhibited in diabetic mice in comparison to control mice. Interestingly, chloroquine enhanced EDR in diabetic coronary arteries by, specifically, increasing EDH-dependent relaxation due partly to its augmenting effect on gap junction activity in diabetic mouse coronary endothelial cells. CONCLUSIONS AND IMPLICATIONS These data indicate that chloroquine affects vascular relaxation differently under normal and diabetic conditions. Therefore, the patients' health condition such as coronary macrovascular or microvascular disease, with or without diabetes, must be taken account into the consideration when selecting chloroquine for the treatment of malaria.
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Affiliation(s)
- Qian Zhang
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Physiology, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | | | - Conor Willson
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Makiko Watanabe
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Rui Si
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Ning Lai
- Department of Medicine, University of California, San Diego, La Jolla, California.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ziyi Wang
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Medicine, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jason X-J Yuan
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Medicine, The University of Arizona, Tucson, Arizona
| | - Jian Wang
- Department of Medicine, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ayako Makino
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Physiology, The University of Arizona, Tucson, Arizona.,Department of Medicine, The University of Arizona, Tucson, Arizona
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13
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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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14
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Pogoda K, Kameritsch P. Molecular regulation of myoendothelial gap junctions. Curr Opin Pharmacol 2019; 45:16-22. [DOI: 10.1016/j.coph.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/14/2019] [Accepted: 03/15/2019] [Indexed: 11/16/2022]
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15
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Kim NK, Santos-Miranda A, Chen H, Aoyama H, Bai D. Heterotypic docking compatibility of human connexin37 with other vascular connexins. J Mol Cell Cardiol 2019; 127:194-203. [PMID: 30594540 DOI: 10.1016/j.yjmcc.2018.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/03/2018] [Accepted: 12/26/2018] [Indexed: 01/18/2023]
Abstract
Human vascular connexins (Cx37, Cx40, Cx43, and Cx45) can form various types of gap junction channels to synchronize vasodilation/constriction to control local circulation. Most of our knowledge on heterotypic gap junctions of these vascular connexins was from studies on rodent connexins. In human vasculature, the same four homolog connexins exist, but whether these human connexins can form heterotypic GJs as those of rodents have not been fully studied. Here we used in vitro expression system to study the coupling status and GJ channel properties of human heterotypic Cx37/Cx40, Cx37/Cx43, and Cx37/Cx45 GJs. Our results showed that Cx37/Cx43 and Cx37/Cx45 GJs, but not Cx37/Cx40 GJs, were functional and each with unique rectifying channel properties. The failure of docking between Cx37 and Cx40 could be rescued by designed Cx40 variants. Characterization of the heterotypic Cx37/Cx43 and Cx37/Cx45 GJs may help us in understanding the intercellular communication at the myoendothelial junction.
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Affiliation(s)
- Nicholas K Kim
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Artur Santos-Miranda
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Honghong Chen
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Hiroshi Aoyama
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Donglin Bai
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
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16
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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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17
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Abstract
Veins exhibit spontaneous contractile activity, a phenomenon generally termed vasomotion. This is mediated by spontaneous rhythmical contractions of mural cells (i.e. smooth muscle cells (SMCs) or pericytes) in the wall of the vessel. Vasomotion occurs through interconnected oscillators within and between mural cells, entraining their cycles. Pharmacological studies indicate that a key oscillator underlying vasomotion is the rhythmical calcium ion (Ca2+) release-refill cycle of Ca2+ stores. This occurs through opening of inositol 1,4,5-trisphosphate receptor (IP3R)- and/or ryanodine receptor (RyR)-operated Ca2+ release channels in the sarcoplasmic/endoplasmic (SR/ER) reticulum and refilling by the SR/ER reticulum Ca2+ATPase (SERCA). Released Ca2+ from stores near the plasma membrane diffuse through the cytosol to open Ca2+-activated chloride (Cl-) channels, this generating inward current through an efflux of Cl-. The resultant depolarisation leads to the opening of voltage-dependent Ca2+ channels and possibly increased production of IP3, which through Ca2+-induced Ca2+ release (CICR) of IP3Rs and/or RyRs and IP3R-mediated Ca2+ release provide a means by which store oscillators entrain their activity. Intercellular entrainment normally involves current flow through gap junctions that interconnect mural cells and in many cases this is aided by additional connectivity through the endothelium. Once entrainment has occurred the substantial Ca2+ entry that results from the near-synchronous depolarisations leads to rhythmical contractions of the mural cells, this often leading to vessel constriction. The basis for venous/venular vasomotion has yet to be fully delineated but could improve both venous drainage and capillary/venular absorption of blood plasma-associated fluids.
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18
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Htet M, Nally JE, Shaw A, Foote BE, Martin PE, Dempsie Y. Connexin 43 Plays a Role in Pulmonary Vascular Reactivity in Mice. Int J Mol Sci 2018; 19:E1891. [PMID: 29954114 PMCID: PMC6073802 DOI: 10.3390/ijms19071891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/07/2018] [Accepted: 06/20/2018] [Indexed: 11/25/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a chronic condition characterized by vascular remodeling and increased vaso-reactivity. PAH is more common in females than in males (~3:1). Connexin (Cx)43 has been shown to be involved in cellular communication within the pulmonary vasculature. Therefore, we investigated the role of Cx43 in pulmonary vascular reactivity using Cx43 heterozygous (Cx43+/−) mice and 37,43Gap27, which is a pharmacological inhibitor of Cx37 and Cx43. Contraction and relaxation responses were studied in intra-lobar pulmonary arteries (IPAs) derived from normoxic mice and hypoxic mice using wire myography. IPAs from male Cx43+/− mice displayed a small but significant increase in the contractile response to endothelin-1 (but not 5-hydroxytryptamine) under both normoxic and hypoxic conditions. There was no difference in the contractile response to endothelin-1 (ET-1) or 5-hydroxytryptamine (5-HT) in IPAs derived from female Cx43+/−mice compared to wildtype mice. Relaxation responses to methacholine (MCh) were attenuated in IPAs from male and female Cx43+/− mice or by pre-incubation of IPAs with 37,43Gap27. Nω-Nitro-L-arginine methyl ester (l-NAME) fully inhibited MCh-induced relaxation. In conclusion, Cx43 is involved in nitric oxide (NO)-induced pulmonary vascular relaxation and plays a gender-specific and agonist-specific role in pulmonary vascular contractility. Therefore, reduced Cx43 signaling may contribute to pulmonary vascular dysfunction.
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Affiliation(s)
- Myo Htet
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Jane E Nally
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Andrew Shaw
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Bradley E Foote
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Patricia E Martin
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Yvonne Dempsie
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
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19
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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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20
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Wang LJ, Ma KT, Shi WY, Wang YZ, Zhao L, Chen XY, Li XZ, Jiang XW, Zhang ZS, Li L, Si JQ. Enhanced gap junctional channel activity between vascular smooth muscle cells in cerebral artery of spontaneously hypertensive rats. Clin Exp Hypertens 2017; 39:295-305. [PMID: 28513236 DOI: 10.1080/10641963.2016.1235181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of the present study is to investigate the effects of hypertension on the gap junctions between vascular smooth muscle cells (VSMCs) in the cerebral arteries (CAs) of spontaneously hypertensive rats (SHRs). The functions of gap junctions in the CAs of VSMCs in SHRs and control normotensive Wistar-Kyoto (WKY) rats were studied using whole-cell patch clamp recordings and pressure myography, and the expression levels of connexins were analyzed using reverse transcription-quantitative polymerase chain reaction and Western blot analyses. Whole-cell patch clamp measurements revealed that the membrane capacitance and conductance of in situ VSMCs in the CAs were significantly greater in SHRs than in WKY rats, suggesting that gap junction coupling is enhanced between VSMCs in the CAs of SHRs. Application of the endothelium-independent vasoconstrictors KCl or phenylephrine (PE) stimulated a greater vasoconstriction in the CAs of SHRs than in those of WKY rats. The EC50 value of KCl was 24.9 mM (n = 14) and 36.9 mM (n=12) for SHRs and WKY rats, respectively. The EC50 value of PE was 0.9 µM (n = 7) and 2.2 µM (n = 7) for SHRs and WKY rats, respectively. Gap junction inhibitors 18β-glycyrrhetinic acid (18β-GA), niflumic acid (NFA), and 2-aminoethoxydiphenyl borate (2-APB) attenuated KCl-induced vasoconstriction in SHRs and WKY rats. The mRNA and protein expression levels of the gap junction protein connexin 45 (Cx45) were significantly higher in the CAs of SHRs than in those of WKY rats. Phosphorylated Cx43 protein expression was significantly higher in the CAs of SHRs than in those of WKY rats, despite the total Cx43 mRNA and protein expression levels in the cerebral artery (CA) exhibiting no significant difference between SHRs and WKY rats. Increases in the expression of Cx45 and phosphorylation of Cx43 may promote gap junction communication among VSMCs in the CAs of SHRs, which may enhance the contractile response of the CA to vasoconstrictors.
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Affiliation(s)
- Li-Jie Wang
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China
| | - Ke-Tao Ma
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China
| | - Wen-Yan Shi
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,c Department of Physiology , Huazhong University of Science and Technology of Basic Medical Sciences , Wuhan , China
| | - Ying-Zi Wang
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China
| | - Lei Zhao
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China
| | - Xin-Yan Chen
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China
| | - Xin-Zhi Li
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China
| | - Xue-Wei Jiang
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China
| | - Zhong-Shuang Zhang
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China
| | - Li Li
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China
| | - Jun-Qiang Si
- a Department of Physiology , Medical College of Shihezi University , Shihezi , China.,b The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University , Shihezi , China.,c Department of Physiology , Huazhong University of Science and Technology of Basic Medical Sciences , Wuhan , China.,d Department of Physiology , Wuhan University School of Basic Medical Sciences , Wuhan , China
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21
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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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22
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Kauffenstein G, Tamareille S, Prunier F, Roy C, Ayer A, Toutain B, Billaud M, Isakson BE, Grimaud L, Loufrani L, Rousseau P, Abraham P, Procaccio V, Monyer H, de Wit C, Boeynaems JM, Robaye B, Kwak BR, Henrion D. Central Role of P2Y6 UDP Receptor in Arteriolar Myogenic Tone. Arterioscler Thromb Vasc Biol 2016; 36:1598-606. [PMID: 27255725 DOI: 10.1161/atvbaha.116.307739] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 05/17/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Myogenic tone (MT) of resistance arteries ensures autoregulation of blood flow in organs and relies on the intrinsic property of smooth muscle to contract in response to stretch. Nucleotides released by mechanical strain on cells are responsible for pleiotropic vascular effects, including vasoconstriction. Here, we evaluated the contribution of extracellular nucleotides to MT. APPROACH AND RESULTS We measured MT and the associated pathway in mouse mesenteric resistance arteries using arteriography for small arteries and molecular biology. Of the P2 receptors in mouse mesenteric resistance arteries, mRNA expression of P2X1 and P2Y6 was dominant. P2Y6 fully sustained UDP/UTP-induced contraction (abrogated in P2ry6(-/-) arteries). Preventing nucleotide hydrolysis with the ectonucleotidase inhibitor ARL67156 enhanced pressure-induced MT by 20%, whereas P2Y6 receptor blockade blunted MT in mouse mesenteric resistance arteries and human subcutaneous arteries. Despite normal hemodynamic parameters, P2ry6(-/-) mice were protected against MT elevation in myocardial infarction-induced heart failure. Although both P2Y6 and P2Y2 receptors contributed to calcium mobilization, P2Y6 activation was mandatory for RhoA-GTP binding, myosin light chain, P42-P44, and c-Jun N-terminal kinase phosphorylation in arterial smooth muscle cells. In accordance with the opening of a nucleotide conduit in pressurized arteries, MT was altered by hemichannel pharmacological inhibitors and impaired in Cx43(+/-) and P2rx7(-/-) mesenteric resistance arteries. CONCLUSIONS Signaling through P2 nucleotide receptors contributes to MT. This mechanism encompasses the release of nucleotides coupled to specific autocrine/paracrine activation of the uracil nucleotide P2Y6 receptor and may contribute to impaired tissue perfusion in cardiovascular diseases.
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Affiliation(s)
- Gilles Kauffenstein
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.).
| | - Sophie Tamareille
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Fabrice Prunier
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Charlotte Roy
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Audrey Ayer
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Bertrand Toutain
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Marie Billaud
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Brant E Isakson
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Linda Grimaud
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Laurent Loufrani
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Pascal Rousseau
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Pierre Abraham
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Vincent Procaccio
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Hannah Monyer
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Cor de Wit
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Jean-Marie Boeynaems
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Bernard Robaye
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Brenda R Kwak
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
| | - Daniel Henrion
- From the MITOVASC Institute, CNRS UMR 6214, INSERM U1083 (G.K., C.R., A.A., B.T., L.G., L.L., P.A., V.P., D.H.) and EA 3860 Cardioprotection Remodelage et Thrombose, University of Angers, Angers, France (S.T., F.P.); Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville (M.B., B.E.I.); University Hospital Angers, Angers, France (G.K., P.R., P.A., V.P.); Department of Clinical Neurobiology, University Hospital and German Cancer Research Center Heidelberg, Heidelberg, Germany (H.M.); Institut für Physiologie, Universität zu Lübeck and Deutsches Zentrum für Herz-Kreislauf-Forschung, Lübeck, Germany (C.d.W.); Institute of Interdisciplinary Research, IRIBHM, Université Libre de Bruxelles, Gosselies, Belgium (J.-M.B., B.R.); and Departments of Pathology and Immunology and Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.)
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Segal SS. Integration and Modulation of Intercellular Signaling Underlying Blood Flow Control. J Vasc Res 2015; 52:136-57. [PMID: 26368324 DOI: 10.1159/000439112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/30/2015] [Indexed: 01/25/2023] Open
Abstract
Vascular resistance networks control tissue blood flow in concert with regulating arterial perfusion pressure. In response to increased metabolic demand, vasodilation arising in arteriolar networks ascends to encompass proximal feed arteries. By reducing resistance upstream, ascending vasodilation (AVD) increases blood flow into the microcirculation. Once initiated, e.g. through local activation of K(+) channels in endothelial cells (ECs), hyperpolarization is conducted through gap junctions along the endothelium. Via EC projections through the internal elastic lamina, hyperpolarization spreads into the surrounding smooth-muscle cells (SMCs) through myoendothelial gap junctions (MEGJs) to promote their relaxation. Intercellular signaling through electrical signal transmission (i.e. cell-to-cell conduction) can thereby coordinate vasodilation along and among the branches of microvascular resistance networks. Perivascular sympathetic nerve fibers course through the adventitia and release norepinephrine to stimulate SMCs via α-adrenoreceptors to produce contraction. In turn, SMCs can signal ECs through MEGJs to activate K(+) channels and attenuate sympathetic vasoconstriction. Activation of K(+) channels along the endothelium will dissipate electrical signal transmission and inhibit AVD, thereby restricting blood flow into the microcirculation while maintaining peripheral resistance and perfusion pressure. This review explores the origins and nature of the intercellular signaling that governs blood flow control in skeletal muscle with respect to the interplay between AVD and sympathetic innervation. Whereas these interactions are integral to daily activity and athletic performance, determining the interplay between respective signaling events provides insight into how selective interventions can improve tissue perfusion and oxygen delivery during vascular disease.
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Kerr PM, Wei R, Tam R, Sandow SL, Murphy TV, Ondrusova K, Lunn SE, Tran CHT, Welsh DG, Plane F. Activation of endothelial IKCa channels underlies NO-dependent myoendothelial feedback. Vascul Pharmacol 2015; 74:130-138. [PMID: 26362477 DOI: 10.1016/j.vph.2015.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 08/26/2015] [Accepted: 09/07/2015] [Indexed: 12/30/2022]
Abstract
Agonist-induced vasoconstriction triggers a negative feedback response whereby movement of charged ions through gap junctions and/or release of endothelium-derived (NO) limit further reductions in diameter, a mechanism termed myoendothelial feedback. Recent studies indicate that electrical myoendothelial feedback can be accounted for by flux of inositol trisphosphate (IP3) through myoendothelial gap junctions resulting in localized increases in endothelial Ca(2+) to activate intermediate conductance calcium-activated potassium (IKCa) channels, the resultant hyperpolarization then conducting back to the smooth muscle to attenuate agonist-induced depolarization and tone. In the present study we tested the hypothesis that activation of IKCa channels underlies NO-mediated myoendothelial feedback. Functional experiments showed that block of IP3 receptors, IKCa channels, gap junctions and transient receptor potential canonical type-3 (TRPC3) channels caused endothelium-dependent potentiation of agonist-induced increase in tone which was not additive with that caused by inhibition of NO synthase supporting a role for these proteins in NO-mediated myoendothelial feedback. Localized densities of IKCa and TRPC3 channels occurred at the internal elastic lamina/endothelial-smooth muscle interface in rat basilar arteries, potential communication sites between the two cell layers. Smooth muscle depolarization to contractile agonists was accompanied by IKCa channel-mediated endothelial hyperpolarization providing the first demonstration of IKCa channel-mediated hyperpolarization of the endothelium in response to contractile agonists. Inhibition of IKCa channels, gap junctions, TRPC3 channels or NO synthase potentiated smooth muscle depolarization to agonists in a non-additive manner. Together these data indicate that rather being distinct pathways for the modulation of smooth muscle tone, NO and endothelial IKCa channels are involved in an integrated mechanism for the regulation of agonist-induced vasoconstriction.
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Affiliation(s)
- Paul M Kerr
- Faculty of Health and Community Studies, MacEwan University, Robbins Health Learning Centre, Edmonton, Alberta T5J 4S2, Canada.
| | - Ran Wei
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Raymond Tam
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Shaun L Sandow
- Inflammation and Healing Cluster, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
| | - Timothy V Murphy
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW2052, Australia.
| | - Katarina Ondrusova
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Stephanie E Lunn
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Cam Ha T Tran
- Hotchkiss Brain and Libin Cardiovascular Research Institutes, Department of Physiology & Pharmacology, University of Calgary, AlbertaT2N-4N1, Canada.
| | - Donald G Welsh
- Hotchkiss Brain and Libin Cardiovascular Research Institutes, Department of Physiology & Pharmacology, University of Calgary, AlbertaT2N-4N1, Canada.
| | - Frances Plane
- Cardiovascular Research Centre, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada; Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
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Hald BO, Welsh DG, Holstein-Rathlou NH, Jacobsen JCB. Gap junctions suppress electrical but not [Ca(2+)] heterogeneity in resistance arteries. Biophys J 2015; 107:2467-76. [PMID: 25418315 DOI: 10.1016/j.bpj.2014.09.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/03/2014] [Accepted: 09/30/2014] [Indexed: 01/03/2023] Open
Abstract
Despite stochastic variation in the molecular composition and morphology of individual smooth muscle and endothelial cells, the membrane potential along intact microvessels is remarkably uniform. This is crucial for coordinated vasomotor responses. To investigate how this electrical homogeneity arises, a virtual arteriole was developed that introduces variation in the activities of ion-transport proteins between cells. By varying the level of heterogeneity and subpopulations of gap junctions (GJs), the resulting simulations shows that GJs suppress electrical variation but can only reduce cytosolic [Ca(2+)] variation. The process of electrical smoothing, however, introduces an energetic cost due to permanent currents, one which is proportional to the level of heterogeneity. This cost is particularly large when electrochemically different endothelial-cell and smooth-muscle-cell layers are coupled. Collectively, we show that homocellular GJs in a passively open state are crucial for electrical uniformity within the given cell layer, but homogenization may be limited by biophysical or energetic constraints. Owing to the ubiquitous presence of ion transport-proteins and cell-cell heterogeneity in biological tissues, these findings generalize across most biological fields.
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Affiliation(s)
- Bjørn Olav Hald
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Donald G Welsh
- Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada
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Liu Z, Wang Q, Fan L, Wu DP, Zhang Y, Liu L, Tao L. Gap junction enhances phototoxicity of photodynamic therapy agent 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH). Lasers Surg Med 2014; 47:68-76. [DOI: 10.1002/lsm.22311] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2014] [Indexed: 01/23/2023]
Affiliation(s)
- Zhen Liu
- Department of Pharmacology; Zhongshan School of Medicine; Sun Yat-Sen University; 74 Zhongshan 2nd Road Guangzhou 510080 China
| | - Qin Wang
- Department of Pharmacology; Zhongshan School of Medicine; Sun Yat-Sen University; 74 Zhongshan 2nd Road Guangzhou 510080 China
| | - Lixia Fan
- Department of Pharmacology; Zhongshan School of Medicine; Sun Yat-Sen University; 74 Zhongshan 2nd Road Guangzhou 510080 China
| | - Deng Pan Wu
- Department of Pharmacology; Pharmacy School of Xuzhou Medical College; China
| | - Yuan Zhang
- Department of Pharmacology; Zhongshan School of Medicine; Sun Yat-Sen University; 74 Zhongshan 2nd Road Guangzhou 510080 China
| | - Lucy Liu
- Department of Cell & Systems Biology; University of Toronto; Ontario M5S 3G5 Canada
| | - Liang Tao
- Department of Pharmacology; Zhongshan School of Medicine; Sun Yat-Sen University; 74 Zhongshan 2nd Road Guangzhou 510080 China
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Ampey BC, Morschauser TJ, Lampe PD, Magness RR. Gap junction regulation of vascular tone: implications of modulatory intercellular communication during gestation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 814:117-32. [PMID: 25015806 DOI: 10.1007/978-1-4939-1031-1_11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In the vasculature, gap junctions (GJ) play a multifaceted role by serving as direct conduits for cell-cell intercellular communication via the facilitated diffusion of signaling molecules. GJs are essential for the control of gene expression and coordinated vascular development in addition to vascular function. The coupling of endothelial cells to each other, as well as with vascular smooth muscle cells via GJs, plays a relevant role in the control of vasomotor tone, tissue perfusion and arterial blood pressure. The regulation of cell-signaling is paramount to cardiovascular adaptations of pregnancy. Pregnancy requires highly developed cell-to-cell coupling, which is affected partly through the formation of intercellular GJs by Cx43, a gap junction protein, within adjacent cell membranes to help facilitate the increase of uterine blood flow (UBF) in order to ensure adequate perfusion for nutrient and oxygen delivery to the placenta and thus the fetus. One mode of communication that plays a critical role in regulating Cx43 is the release of endothelial-derived vasodilators such as prostacyclin (PGI2) and nitric oxide (NO) and their respective signaling mechanisms involving second messengers (cAMP and cGMP, respectively) that are likely to be important in maintaining UBF. Therefore, the assertion we present in this review is that GJs play an integral if not a central role in maintaining UBF by controlling rises in vasodilators (PGI2 and NO) via cyclic nucleotides. In this review, we discuss: (1) GJ structure and regulation; (2) second messenger regulation of GJ phosphorylation and formation; (3) pregnancy-induced changes in cell-signaling; and (4) the role of uterine arterial endothelial GJs during gestation. These topics integrate the current knowledge of this scientific field with interpretations and hypotheses regarding the vascular effects that are mediated by GJs and their relationship with vasodilatory vascular adaptations required for modulating the dramatic physiological rises in uteroplacental perfusion and blood flow observed during normal pregnancy.
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Affiliation(s)
- Bryan C Ampey
- Perinatal Research Laboratories, Department of Obstetrics & Gynecology, School Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, 53715, USA
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Tran CHT, Kurjiaka DT, Welsh DG. Emerging trend in second messenger communication and myoendothelial feedback. Front Physiol 2014; 5:243. [PMID: 25071588 PMCID: PMC4074893 DOI: 10.3389/fphys.2014.00243] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/11/2014] [Indexed: 01/03/2023] Open
Abstract
Over the past decade, second messenger communication has emerged as one of the intriguing topics in the field of vasomotor control. Of particular interest has been the idea of second messenger flux from smooth muscle to endothelium initiating a feedback response that attenuates constriction. Mechanistic details of the precise signaling cascade have until recently remained elusive. In this perspective, we introduce readers to how myoendothelial gap junctions could enable sufficient inositol trisphosphate flux to initiate endothelial Ca(2+) events that activate Ca(2+) sensitive K(+) channels. The resulting hyperpolarizing current would in turn spread back through the same myoendothelial gap junctions to moderate smooth muscle depolarization and constriction. In discussing this defined feedback mechanism, this brief manuscript will stress the importance of microdomains and of discrete cellular signaling.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Libin Cardiovascular Research Institute, University of Calgary Calgary, AB, Canada ; Department of Physiology and Pharmacology, University of Calgary Calgary, AB, Canada
| | - David T Kurjiaka
- Department of Biomedical Sciences, Grand Valley State University Allendale, MI, USA
| | - Donald G Welsh
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Libin Cardiovascular Research Institute, University of Calgary Calgary, AB, Canada ; Department of Physiology and Pharmacology, University of Calgary Calgary, AB, Canada
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Functional Role of Connexins and Pannexins in the Interaction Between Vascular and Nervous System. J Cell Physiol 2014; 229:1336-45. [DOI: 10.1002/jcp.24563] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 01/16/2014] [Indexed: 01/22/2023]
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Hald BO, Jacobsen JCB, Sandow SL, Holstein-Rathlou NH, Welsh DG. Less is more: minimal expression of myoendothelial gap junctions optimizes cell-cell communication in virtual arterioles. J Physiol 2014; 592:3243-55. [PMID: 24907303 DOI: 10.1113/jphysiol.2014.272815] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Dysfunctional electrical signalling within the arteriolar wall is a major cause of cardiovascular disease. The endothelial cell layer constitutes the primary electrical pathway, co-ordinating contraction of the overlying smooth muscle cell (SMC) layer. As myoendothelial gap junctions (MEGJs) provide direct contact between the cell layers, proper vasomotor responses are thought to depend on a high, uniform MEGJ density. However, MEGJs are observed to be expressed heterogeneously within and among vascular beds. This discrepancy is addressed in the present study. As no direct measures of MEGJ conductance exist, we employed a computational modelling approach to vary the number, conductance and distribution of MEGJs. Our simulations demonstrate that a minimal number of randomly distributed MEGJs augment arteriolar cell-cell communication by increasing conduction efficiency and ensuring appropriate membrane potential responses in SMCs. We show that electrical coupling between SMCs must be tailored to the particular MEGJ distribution. Finally, observation of non-decaying mechanical conduction in arterioles without regeneration has been a long-standing controversy in the microvascular field. As heterogeneous MEGJ distributions provide for different conduction profiles along the cell layers, we demonstrate that a non-decaying conduction profile is possible in the SMC layer of a vessel with passive electrical properties. These intriguing findings redefine the concept of efficient electrical communication in the microcirculation, illustrating how heterogeneous properties, ubiquitous in biological systems, may have a profound impact on system behaviour and how acute local and global flow control is explained from the biophysical foundations.
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Affiliation(s)
- Bjørn Olav Hald
- Department of Biomedical Sciences, University of Copenhagen, Denmark
| | | | - Shaun L Sandow
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | | | - Donald G Welsh
- Department of Physiology & Pharmacology, University of Calgary, Alberta, Canada
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Givvimani S, Narayanan N, Armaghan F, Pushpakumar S, Tyagi SC. Attenuation of conducted vasodilation in skeletal muscle arterioles during hyperhomocysteinemia. Pharmacology 2013; 91:287-96. [PMID: 23736684 DOI: 10.1159/000350394] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/03/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Vasomotor responses conducted from terminal arterioles to proximal vessels may contribute to match tissue demands and blood supply during skeletal muscle contraction. Conduction of vasodilatation (CVD) from distal resistance arterioles to the proximal arterioles and feeding arteries during metabolic demand is mediated by intercellular gap junctions in the vascular endothelium. The role of hyperhomocysteinemia (HHcy) in the musculoskeletal system during CVD is unclear. We hypothesize that during HHcy, there is impaired CVD due to decreased expression of endothelial-associated connexins and thus decreased tissue perfusion to the contracting skeletal muscles. METHODS CVD studies were performed in a gluteus maximus muscle preparation of wild-type (C57BL6/J) and CBS-/+ (HHcy) mice using intravital microscopy. Expression of connexins and myostatin protein (an antiskeletal muscle statin) was studied by Western blot and immunohistochemistry methods. Tissue perfusion to acetylcholine was assessed by the laser Doppler technique. RESULTS There was decreased CVD and tissue perfusion in response to acetylcholine in CBS-/+ mice compared to wild-type controls. There was decreased expression of connexins 37, 40 and 43 and increased expression of myostatin in CBS-/+ mice compared to wild-type controls. CONCLUSION Our findings suggest that CVD in skeletal muscle is decreased during HHcy due to decreased expression of gap junction connexins.
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Affiliation(s)
- S Givvimani
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Ky., USA.
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Socha MJ, Domeier TL, Behringer EJ, Segal SS. Coordination of intercellular Ca(2+) signaling in endothelial cell tubes of mouse resistance arteries. Microcirculation 2013; 19:757-70. [PMID: 22860994 DOI: 10.1111/micc.12000] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 08/01/2012] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To test the hypothesis that Ca(2+) responses to GPCR activation are coordinated between neighboring ECs of resistance arteries. METHODS EC tubes were freshly isolated from superior epigastric arteries of C57BL/6 mice. Intercellular coupling was tested using microinjection of propidium iodide. Following loading with fluo-4 dye, intracellular Ca(2+) responses to ACh were imaged with confocal microscopy. RESULTS Cell-to-cell transfer of propidium iodide confirmed functional GJCs. A 1 μm ACh stimulus evoked Ca(2+) responses (9.8 ± 0.8/min, F/F(0) = 3.11 ± 0.2) which pseudo-line-scan analysis revealed as composed of Ca(2+) waves and spatially restricted Ca(2+) release events. A 100 nm ACh stimulus induced Ca(2+) responses of lower frequency (4.5 ± 0.7/min) and amplitude (F/F(0) = 1.95 ± 0.11) composed primarily of spatially restricted events. The time interval between Ca(2+) waves in adjacent cells (0.79 ± 0.12 s) was shorter (p < 0.05) than that between nonadjacent cells (1.56 ± 0.25 s). Spatially restricted Ca(2+) release events had similar frequencies and latencies between adjacent and nonadjacent cells. Inhibiting intracellular Ca(2+) release with 2-APB, Xestospongin C or thapsigargin eliminated Ca(2+) responses. CONCLUSIONS With moderate GPCR stimulation, localized Ca(2+) release events predominate among cells. Greater GPCR stimulation evokes coordinated intercellular Ca(2+) waves via the ER. Calcium signaling during GPCR activation is complex among cells, varying with stimulus intensity and proximity to actively signaling cells.
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Affiliation(s)
- Matthew J Socha
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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Manasson J, Tien T, Moore C, Kumar NM, Roy S. High glucose-induced downregulation of connexin 30.2 promotes retinal vascular lesions: implications for diabetic retinopathy. Invest Ophthalmol Vis Sci 2013; 54:2361-6. [PMID: 23385797 DOI: 10.1167/iovs.12-10815] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PURPOSE To investigate whether high glucose (HG) alters expression of connexin 30.2 (Cx30.2) and influences gap junction intercellular communication (GJIC) in retinal endothelial cells and promotes vascular lesions characteristic of diabetic retinopathy (DR). METHODS Western blot analysis and immunostaining were performed to determine Cx30.2 protein expression and localization in rat retinal endothelial cells (RRECs) grown in normal (N; 5 mM) or HG (30 mM) medium for 7 days. Concurrently, GJIC was assessed in cells grown in N or HG medium and in cells transfected with Cx30.2 siRNA. Similarly, retinal Cx30.2 expression was assessed in nondiabetic and diabetic rats. Additionally, the effect of reduced Cx30.2 on development of acellular capillaries (ACs) and pericyte loss (PL) was studied in retinas of Cx30.2 knockout mice. RESULTS Cx30.2 was identified in RRECs in vitro and in vascular cells of retinal capillaries. RRECs grown in HG exhibited significantly reduced Cx30.2 protein levels consistent with decreased Cx30.2 immunostaining compared with those grown in N medium. Cells grown in HG and cells transfected with Cx30.2 siRNA exhibited significantly diminished dye transfer compared with N or nontransfected cells. Importantly, Cx30.2 protein level and immunostaining were decreased in diabetic retinas compared with nondiabetic retinas. Retinal capillaries of Cx30.2 knockout mice exhibited increased numbers of ACs and PL compared with those of wild-type mice. CONCLUSIONS These results indicate that HG- or diabetes-induced downregulation of Cx30.2 expression and decrease in GJIC activity play a critical role in the development of retinal vascular lesions in early DR.
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Affiliation(s)
- Julia Manasson
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Nagaraja S, Kapela A, Tran CH, Welsh DG, Tsoukias NM. Role of microprojections in myoendothelial feedback--a theoretical study. J Physiol 2013; 591:2795-812. [PMID: 23529128 DOI: 10.1113/jphysiol.2012.248948] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated the role of myoendothelial projections (MPs) in endothelial cell (EC) feedback response to smooth muscle cell (SMC) stimulation using mathematical modelling. A previously developed compartmental EC-SMC model is modified to include MPs as subcellular compartments in the EC. The model is further extended into a 2D continuum model using a finite element method (FEM) approach and electron microscopy images to account for MP geometry. The EC and SMC are coupled via non-selective myoendothelial gap junctions (MEGJs) which are located on MPs and allow exchange of Ca(2+), K(+), Na(+) and Cl(-) ions and inositol 1,4,5-triphosphate (IP3). Models take into consideration recent evidence for co-localization of intermediate-conductance calcium-activated potassium channels (IKCa) and IP3 receptors (IP3Rs) in the MPs. SMC stimulation causes an IP3-mediated Ca(2+) transient in the MPs with limited global spread in the bulk EC. A hyperpolarizing feedback generated by the localized IKCa channels is transmitted to the SMC via MEGJs. MEGJ resistance (Rgj) and the density of IKCa and IP3R in the projection influence the extent of EC response to SMC stimulation. The predicted Ca(2+) transients depend also on the volume and geometry of the MP. We conclude that in the myoendothelial feedback response to SMC stimulation, MPs are required to amplify the SMC initiated signal. Simulations suggest that the signal is mediated by IP3 rather than Ca(2+) diffusion and that a localized rather than a global EC Ca(2+) mobilization is more likely following SMC stimulation.
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Affiliation(s)
- Sridevi Nagaraja
- Department of Biomedical Engineering, Florida International University, 10555 W. Flagler Street, EC 2674, Miami, FL 33174. USA
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Boedtkjer E, Kim S, Aalkjaer C. Endothelial alkalinisation inhibits gap junction communication and endothelium-derived hyperpolarisations in mouse mesenteric arteries. J Physiol 2013; 591:1447-61. [PMID: 23297309 DOI: 10.1113/jphysiol.2012.247478] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Abstract Gap junctions mediate intercellular signalling in arteries and contribute to endothelium-dependent vasorelaxation, conducted vascular responses and vasomotion. Considering its putative role in vascular dysfunction, mechanistic insights regarding the control of gap junction conductivity are required. Here, we investigated the consequences of endothelial alkalinisation for gap junction communication and endothelium-dependent vasorelaxation in resistance arteries. We studied mesenteric arteries from NMRI mice by myography, confocal fluorescence microscopy and electrophysiological techniques. Removing CO2/HCO3(-), reducing extracellular [Cl(-)] or adding 4,4-diisothiocyanatostilbene-2,2-disulphonic acid inhibited or reversed Cl(-)/HCO3(-) exchange, alkalinised the endothelium by 0.2-0.3 pH units and inhibited acetylcholine-induced vasorelaxation. NO-synthase-dependent vasorelaxation was unaffected by endothelial alkalinisation whereas vasorelaxation dependent on small- and intermediate-conductance Ca(2+)-activated K(+) channels was attenuated by ∼75%. The difference in vasorelaxation between arteries with normal and elevated endothelial intracellular pH (pHi) was abolished by the gap junction inhibitors 18β-glycyrrhetinic acid and carbenoxolone while other putative modulators of endothelium-derived hyperpolarisations - Ba(2+), ouabain, iberiotoxin, 8Br-cAMP and polyethylene glycol catalase - had no effect. In the absence of CO2/HCO3(-), addition of the Na(+)/H(+)-exchange inhibitor cariporide normalised endothelial pHi and restored vasorelaxation to acetylcholine. Endothelial hyperpolarisations and Ca(2+) responses to acetylcholine were unaffected by omission of CO2/HCO3(-). By contrast, dye transfer between endothelial cells and endothelium-derived hyperpolarisations of vascular smooth muscle cells stimulated by acetylcholine or the proteinase-activated receptor 2 agonist SLIGRL-amide were inhibited in the absence of CO2/HCO3(-). We conclude that intracellular alkalinisation of endothelial cells attenuates endothelium-derived hyperpolarisations in resistance arteries due to inhibition of gap junction communication. These findings highlight the role of pHi in modulating vascular function.
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Affiliation(s)
- Ebbe Boedtkjer
- E. Boedtkjer: Department of Biomedicine, Aarhus University, Ole Worms Allé 6, Building 1180, DK-8000 Aarhus C, Denmark.
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Tran CHT, Vigmond EJ, Goldman D, Plane F, Welsh DG. Electrical communication in branching arterial networks. Am J Physiol Heart Circ Physiol 2012; 303:H680-92. [PMID: 22796538 DOI: 10.1152/ajpheart.00261.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electrical communication and its role in blood flow regulation are built on an examination of charge movement in single, isolated vessels. How this process behaves in broader arterial networks remains unclear. This study examined the nature of electrical communication in arterial structures where vessel length and branching were varied. Analysis began with the deployment of an existing computational model expanded to form a variable range of vessel structures. Initial simulations revealed that focal endothelial stimulation generated electrical responses that conducted robustly along short unbranched vessels and to a lesser degree lengthened arteries or branching structures retaining a single branch point. These predictions matched functional observations from hamster mesenteric arteries and support the idea that an increased number of vascular cells attenuate conduction by augmenting electrical load. Expanding the virtual network to 31 branches revealed that electrical responses increasingly ascended from fifth- to first-order arteries when the number of stimulated distal vessels rose. This property enabled the vascular network to grade vasodilation and network perfusion as revealed through blood flow modeling. An elevation in endothelial-endothelial coupling resistance, akin to those in sepsis models, compromised this ascension of vasomotor/perfusion responses. A comparable change was not observed when the endothelium was focally disrupted to mimic disease states including atherosclerosis. In closing, this study highlights that vessel length and branching play a role in setting the conduction of electrical phenomenon along resistance arteries and within networks. It also emphasizes that modest changes in endothelial function can, under certain scenarios, impinge on network responsiveness and blood flow control.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain and Libin Cardiovascular Research Institute, University of Calgary, Alberta, Canada
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KERR PAULM, TAM RAYMOND, ONDRUSOVA KATARINA, MITTAL ROHAN, NARANG DEEPAK, TRAN CAMHAT, WELSH DONALDG, PLANE FRANCES. Endothelial Feedback and the Myoendothelial Projection. Microcirculation 2012; 19:416-22. [DOI: 10.1111/j.1549-8719.2012.00187.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tran CHT, Taylor MS, Plane F, Nagaraja S, Tsoukias NM, Solodushko V, Vigmond EJ, Furstenhaupt T, Brigdan M, Welsh DG. Endothelial Ca2+ wavelets and the induction of myoendothelial feedback. Am J Physiol Cell Physiol 2012; 302:C1226-42. [PMID: 22277756 DOI: 10.1152/ajpcell.00418.2011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
When arteries constrict to agonists, the endothelium inversely responds, attenuating the initial vasomotor response. The basis of this feedback mechanism remains uncertain, although past studies suggest a key role for myoendothelial communication in the signaling process. The present study examined whether second messenger flux through myoendothelial gap junctions initiates a negative-feedback response in hamster retractor muscle feed arteries. We specifically hypothesized that when agonists elicit depolarization and a rise in second messenger concentration, inositol trisphosphate (IP(3)) flux activates a discrete pool of IP(3) receptors (IP(3)Rs), elicits localized endothelial Ca(2+) transients, and activates downstream effectors to moderate constriction. With use of integrated experimental techniques, this study provided three sets of supporting observations. Beginning at the functional level, we showed that blocking intermediate-conductance Ca(2+)-activated K(+) channels (IK) and Ca(2+) mobilization from the endoplasmic reticulum (ER) enhanced the contractile/electrical responsiveness of feed arteries to phenylephrine. Next, structural analysis confirmed that endothelial projections make contact with the overlying smooth muscle. These projections retained membranous ER networks, and IP(3)Rs and IK channels localized in or near this structure. Finally, Ca(2+) imaging revealed that phenylephrine induced discrete endothelial Ca(2+) events through IP(3)R activation. These events were termed recruitable Ca(2+) wavelets on the basis of their spatiotemporal characteristics. From these findings, we conclude that IP(3) flux across myoendothelial gap junctions is sufficient to induce focal Ca(2+) release from IP(3)Rs and activate a discrete pool of IK channels within or near endothelial projections. The resulting hyperpolarization feeds back on smooth muscle to moderate agonist-induced depolarization and constriction.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain and Libin Cardiovascular Research Institute, Department of Physiology and Pharmacology, University of Calgary, Canada
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Abstract
This review is concerned with understanding how vasodilation initiated from local sites in the tissue can spread to encompass multiple branches of the resistance vasculature. Within tissues, arteriolar networks control the distribution and magnitude of capillary perfusion. Vasodilation arising from the microcirculation can 'ascend' into feed arteries that control blood flow into arteriolar networks. Thus distal segments of the resistance network signal proximal segments to dilate and thereby increase total oxygen supply to parenchymal cells. August Krogh proposed that innervation of capillaries provided the mechanism for a spreading vasodilatory response. With greater understanding of the ultrastructural organization of resistance networks, an alternative explanation has emerged: Electrical signalling from cell to cell along the vessel wall through gap junctions. Hyperpolarization originates from ion channel activation at the site of stimulation with the endothelium serving as the predominant cellular pathway for signal conduction along the vessel wall. As hyperpolarization travels, it is transmitted into surrounding smooth muscle cells through myoendothelial coupling to promote relaxation. Conducted vasodilation (CVD) encompasses greater distances than can be explained by passive decay and understanding such behaviour is the focus of current research efforts. In the context of athletic performance, the ability of vasodilation to ascend into feed arteries is essential to achieving peak levels of muscle blood flow. CVD is tempered by sympathetic neuroeffector signalling when governing muscle blood flow at rest and during exercise. Impairment of conduction during ageing and in diseased states can limit physical work capacity by restricting muscle blood flow.
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Affiliation(s)
- P Bagher
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Abstract
This minireview discusses vasomotion, which is the oscillation in tone of blood vessels leading to flowmotion. We will briefly discuss the prevalence of vasomotion and its potential physiological and pathophysiological relevance. We will also discuss the models that have been suggested to explain how a coordinated oscillatory activity of the smooth muscle tone can occur and emphasize the role of the endothelium, the handling of intracellular Ca(2+) and the role of smooth muscle cell ion conductances. It is concluded that vasomotion is likely to enhance tissue dialysis, although this concept still requires more experimental verification, and that an understanding at the molecular level for the pathways leading to vasomotion is beginning to emerge.
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Affiliation(s)
- C Aalkjær
- Department of Physiology and Biophysics, The Water and Salt Centre, Aarhus University, Denmark.
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Maeda S, Tsukihara T. Structure of the gap junction channel and its implications for its biological functions. Cell Mol Life Sci 2011; 68:1115-29. [PMID: 20960023 PMCID: PMC11114897 DOI: 10.1007/s00018-010-0551-z] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 12/16/2022]
Abstract
Gap junctions consist of arrays of intercellular channels composed of integral membrane proteins called connexin in vertebrates. Gap junction channels regulate the passage of ions and biological molecules between adjacent cells and, therefore, are critically important in many biological activities, including development, differentiation, neural activity, and immune response. Mutations in connexin genes are associated with several human diseases, such as neurodegenerative disease, skin disease, deafness, and developmental abnormalities. The activity of gap junction channels is regulated by the membrane voltage, intracellular microenvironment, interaction with other proteins, and phosphorylation. Each connexin channel has its own property for conductance and molecular permeability. A number of studies have tried to reveal the molecular architecture of the channel pore that should confer the connexin-specific permeability/selectivity properties and molecular basis for the gating and regulation. In this review, we give an overview of structural studies and describe the structural and functional relationship of gap junction channels.
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Affiliation(s)
- Shoji Maeda
- Institute for Protein Research, Osaka University, OLABB, 6-2-3 Furuedai, Suita, 565-0874 Japan
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamighori, Akoh, Hyogo 678-1297 Japan
- Present Address: Paul Scherrer Institut, Biology and Chemistry OFLG 101, 5232 Villigen, Switzerland
| | - Tomitake Tsukihara
- Institute for Protein Research, Osaka University, OLABB, 6-2-3 Furuedai, Suita, 565-0874 Japan
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamighori, Akoh, Hyogo 678-1297 Japan
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Tyml K. Role of connexins in microvascular dysfunction during inflammation. Can J Physiol Pharmacol 2011; 89:1-12. [DOI: 10.1139/y10-099] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In arterioles, a locally initiated diameter change can propagate rapidly along the vessel length (arteriolar conducted response), thus contributing to arteriolar hemodynamic resistance. The response is underpinned by electrical coupling along the arteriolar endothelial layer. Connexins (Cx; constituents of gap junctions) are required for this coupling. This review addresses the effect of acute systemic inflammation (sepsis) on arteriolar conduction and interendothelial electrical coupling. Lipopolysaccharide (LPS; an initiating factor in sepsis) and polymicrobial sepsis (24 h model) attenuate conducted vasoconstriction in mice. In cultured microvascular endothelial cells harvested from rat and mouse skeletal muscle, LPS reduces both conducted hyperpolarization–depolarization along capillary-like structures and electrical coupling along confluent cell monolayers. LPS also tyrosine-phosphorylates Cx43 and serine-dephosphorylates Cx40. Since LPS-reduced coupling is Cx40- but not Cx43-dependent, only Cx40 dephosphorylation may be consequential. Nitric oxide (NO) overproduction is critical in advanced sepsis, since the removal of this overproduction prevents the attenuated conduction. Consistently, (i) exogenous NO in cultured cells reduces coupling in a Cx37-dependent manner, and (ii) the septic microvasculature in vivo shows no Cx40 phenotype. A complex role emerges for endothelial connexins in sepsis. Initially, LPS may reduce interendothelial coupling and arteriolar conduction by targeting Cx40, whereas NO overproduction in advanced sepsis reduces coupling and conduction by targeting Cx37 instead.
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Affiliation(s)
- Karel Tyml
- Department of Medical Biophysics, and Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
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Shen J, Wang LH, Zheng LR, Zhu JH, Hu SJ. Lovastatin inhibits gap junctional communication in cultured aortic smooth muscle cells. J Cardiovasc Pharmacol Ther 2010; 15:296-302. [PMID: 20601591 DOI: 10.1177/1074248410373750] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Gap junctions, which serve as intercellular channels that allow the passage of ions and other small molecules between neighboring cells, play an important role in vital functions, including the regulation of cell growth, differentiation, and development. Statins, the 3-hydroxy-3-methylglutaryl-coenzymeA (HMG-CoA) reductase inhibitors, have been shown to inhibit the migration and proliferation of smooth muscle cells (SMCs) leading to an antiproliferative effect. Recent studies have shown that statins can reduce gap junction protein connexin43 (Cx43) expression both in vivo and in vitro. However, little work has been done on the effects of statins on gap junctional intercellular communication (GJIC). We hypothesized in this study that lovastatin inhibits vascular smooth muscle cells (VSMCs) migration through the inhibition of the GJIC. METHODS Rat aortic SMCs (RASMCs) were exposed to lovastatin. Vascular smooth muscle cells migration was then assessed with a Transwell migration assay. Gap junctional intercellular communication was determined by using fluorescence recovery after photobleaching (FRAP) analysis, which was performed with a laser-scanning confocal microscope. RESULTS The migration of the cultured RASMCs were detected by Transwell system. Cell migration was dose-dependently inhibited with lovastatin. Compared with that in the control (110 ± 26), the number of migrated SMCs was significantly reduced to 72 ± 24 (P < .05), 62 ± 18 (P < .01), and 58 ± 19 (P < .01) at the concentration of 0.4, 2, and 10 umol/L, per field. The rate of fluorescence recovery (R) at 5 minutes after photobleaching was adopted as the functional index of GJIC. The R- value of cells exposed to lovastatin 10 umol/L for 48 hours was 24.38% ± 4.84%, whereas the cells in the control group had an R- value of 36.11% ± 10.53%, demonstrating that the GJIC of RASMCs was significantly inhibited by lovastatin (P < .01). Smaller concentrations of lovastatin 0.08 umol/L did not change gap junction coupling (P > .05). CONCLUSIONS These results suggest that lovastatin inhibits migration in a dose-dependent manner by attenuating JIC. Suppression of gap junction function could add another explanation of statin-induced antiproliferative effect.
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Affiliation(s)
- Jing Shen
- Department of Cardiovascular Sciences, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Buschmann I, Pries A, Styp-Rekowska B, Hillmeister P, Loufrani L, Henrion D, Shi Y, Duelsner A, Hoefer I, Gatzke N, Wang H, Lehmann K, Ulm L, Ritter Z, Hauff P, Hlushchuk R, Djonov V, van Veen T, le Noble F. Pulsatile shear and Gja5 modulate arterial identity and remodeling events during flow-driven arteriogenesis. Development 2010; 137:2187-96. [PMID: 20530546 DOI: 10.1242/dev.045351] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the developing chicken embryo yolk sac vasculature, the expression of arterial identity genes requires arterial hemodynamic conditions. We hypothesize that arterial flow must provide a unique signal that is relevant for supporting arterial identity gene expression and is absent in veins. We analyzed factors related to flow, pressure and oxygenation in the chicken embryo vitelline vasculature in vivo. The best discrimination between arteries and veins was obtained by calculating the maximal pulsatile increase in shear rate relative to the time-averaged shear rate in the same vessel: the relative pulse slope index (RPSI). RPSI was significantly higher in arteries than veins. Arterial endothelial cells exposed to pulsatile shear in vitro augmented arterial marker expression as compared with exposure to constant shear. The expression of Gja5 correlated with arterial flow patterns: the redistribution of arterial flow provoked by vitelline artery ligation resulted in flow-driven collateral arterial network formation and was associated with increased expression of Gja5. In situ hybridization in normal and ligation embryos confirmed that Gja5 expression is confined to arteries and regulated by flow. In mice, Gja5 (connexin 40) was also expressed in arteries. In the adult, increased flow drives arteriogenesis and the formation of collateral arterial networks in peripheral occlusive diseases. Genetic ablation of Gja5 function in mice resulted in reduced arteriogenesis in two occlusion models. We conclude that pulsatile shear patterns may be central for supporting arterial identity, and that arterial Gja5 expression plays a functional role in flow-driven arteriogenesis.
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Affiliation(s)
- Ivo Buschmann
- Experimental and Clinical Research Center (ECRC) of the Charite and the Max-Delbrueck Center for Molecular Medicine (MDC), D13125 Berlin-Buch, Germany
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Li Q, Zhang J, Wang W, Liu J, Zhu H, Chen W, Chen T, Yu S, Wang H, Sun G, Yi D. Connexin40 modulates pulmonary permeability through gap junction channel in acute lung injury after thoracic gunshot wounds. THE JOURNAL OF TRAUMA 2010; 68:802-9. [PMID: 20386276 DOI: 10.1097/ta.0b013e3181bb80ea] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The permeability of pulmonary microvessel endothelial cells increases markedly after acute lung injury via paracellular gap. Connexin40 is a primary component of pulmonary microvessel endothelial cells gap junction channel and mediates intercellular communication. However, the relationship between connexin40 and the permeability of pulmonary microvessel endothelial cells is still unknown. Therefore, we determined whether connexin40 affected rabbits' pulmonary microvessel endothelial cells permeability after acute lung injury induced by gunshot trauma. METHODS We used an acute lung injury model in New Zealand rabbits following gunshot chest trauma and correlated connexin40 immunohistochemistry in gunshot lung tissue with Evans blue leak rate. Cultured pulmonary microvessel endothelial cells were divided into three groups, control (G control), injured serum (G serum), and blocker agent (G blocker). Gap junction channel function was assessed by scrape-loading and dye transfer techniques. Pulmonary microvessel endothelial cells permeability was measured by Evans blue-labeled albumin transfer. RESULTS Connexin40 expression decreased time dependently, whereas Evans blue leak rate increased. Connexin40 expression and Evans blue leak rate exhibited a strong inverse correlation (gamma = -0.934, p < 0.05). Injured serum decreased gap junction channel function, and the gap junction channel blocker aggravated this effect. Similarly, pulmonary microvessel endothelial cells permeability increased significantly in G serum and G blocker. CONCLUSIONS Connexin 40 expression in pulmonary microvasculature endothelial cells is downregulated after acute lung injury induced by gunshot trauma. This is associated with impaired gap junction channel function and increased pulmonary microvessel endothelial cells permeability.
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Affiliation(s)
- Qiang Li
- Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
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TRAN CAMHAT, WELSH DONALDG. The Differential Hypothesis: A Provocative Rationalization of the Conducted Vasomotor Response. Microcirculation 2010; 17:226-36. [DOI: 10.1111/j.1549-8719.2010.00022.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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López D, Rodríguez-Sinovas A, Agulló E, García A, Sánchez JA, García-Dorado D. Replacement of connexin 43 by connexin 32 in a knock-in mice model attenuates aortic endothelium-derived hyperpolarizing factor-mediated relaxation. Exp Physiol 2009; 94:1088-97. [PMID: 19617266 DOI: 10.1113/expphysiol.2009.048413] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies demonstrated that intercellular communication through endothelial, smooth muscle or myoendothelial connexin channels contributes to the control of vascular tone. At least four connexin types are present in the arterial wall. The aim of the present work was to assess the role played by connexin 43 (Cx43)-formed gap junctions on vessel function. Aortic reactivity to noradrenaline, acetylcholine and sodium nitroprusside, and endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxations, were analysed in a Cx43KI32 mouse model in which the coding region of Cx43 was replaced by that of connexin 32 (Cx32). Aortic rings were placed in organ baths containing a Krebs solution oxygenated at 37 degrees C (pH 7.4). Confocal images of aortic rings confirmed connexin substitution in mutant mice. In control conditions, replacement of Cx43 by Cx32 in homozygous mutant mice did not modify endothelium-independent contractile responses to noradrenaline, or relaxations in response to sodium nitroprusside (endothelium independent) or acetylcholine (endothelium dependent). However, residual endothelium-dependent relaxations in response to acetylcholine after nitric oxide synthase and cyclooxygenase inhibition (EDHF type) were significantly reduced in homozygous Cx43KI32 mice (maximal effect values: 4.86 +/- 0.37% of noradrenaline precontraction versus 7.06 +/- 0.31% in wild-type, n = 8, P < 0.05). This attenuation was mimicked by treatment of rings from wild-type animals with the connexin-mimetic peptide (37,43)Gap27 (5 x 10(-6)m). In conclusion, replacement of Cx43 by Cx32 attenuates EDHF-mediated relaxations in mice aortic rings, suggesting that they are, at least in part, dependent on Cx43-formed gap junctions. In contrast, aortic responses to tested endothelium-independent agonists were not modified in knock-in animals.
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Affiliation(s)
- Diego López
- Institut de Recerca Hospitals Vall d'Hebron, Hospital Universitario Vall d'Hebron, Passeig Vall d'Hebron 119, 08035 Barcelona, Spain
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de Wit C, Boettcher M, Schmidt VJ. Signaling across Myoendothelial Gap Junctions—Fact or fiction? ACTA ACUST UNITED AC 2009; 15:231-45. [DOI: 10.1080/15419060802440260] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Okamoto T, Akiyama M, Takeda M, Gabazza EC, Hayashi T, Suzuki K. Connexin32 is expressed in vascular endothelial cells and participates in gap-junction intercellular communication. Biochem Biophys Res Commun 2009; 382:264-8. [PMID: 19265674 DOI: 10.1016/j.bbrc.2009.02.148] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
Abstract
Endothelial cells (ECs) play many roles in vascular biology, including control of blood pressure, blood clotting, atherosclerosis, angiogenesis, and inflammation. Gap junctions (GJs) are channel-like assemblies of connexin (Cx) family proteins that connect neighboring cells and modulate and synchronize their intracellular environments by the transfer of intracellular mediators. It has been reported that vascular ECs express Cx37, Cx40, and Cx43, but not Cx32. Here, we showed that Cx32 mRNA and protein are expressed in various cultured human ECs. We confirmed Cx32 expression in blood vessel ECs using wild-type and Cx32 knock-out mice. We observed that dye transfer between cultured ECs through gap junctions is suppressed by an anti-Cx32 monoclonal antibody. These findings suggest that vascular ECs express Cx32, which participates in endothelial gap-junction intercellular communication.
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Affiliation(s)
- Takayuki Okamoto
- Department of Molecular Pathobiology, Mie University Graduate School of Medicine, Tsu-city, Mie, Japan
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Braunstein TH, Sorensen CM, Holstein-Rathlou NH. Connexin abundance in resistance vessels from the renal microcirculation in normo- and hypertensive rats. APMIS 2009; 117:268-76. [PMID: 19338515 DOI: 10.1111/j.1600-0463.2009.02432.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The expression of connexins in renal arterioles is believed to have a profound impact on conducted responses, regulation of arteriolar tonus and renal blood flow. We have previously shown that in renal preglomerular arterioles, conducted vasomotor responses are 40% greater in spontaneously hypertensive rats (SHR) than in normotensive Sprague-Dawley (SD) rats. Because conducted vasomotor responses depend on the cell-cell communication mediated through gap junctions, we hypothesized that the increased magnitude of conducted vasomotor response in SHR is associated with an increased amount of connexins in renal arterioles. To test this hypothesis, the amount of connexin 37 (Cx37), Cx40 and Cx43 was assessed in renal arterioles from normo- and hypertensive rats using quantitative immunofluorescence laser confocal microscopy. To account for differences in genetic background, we included both normotensive Wistar-Kyoto (WKY) and SD rats in the study. In all three strains of rats, and for all three isoforms, the expression of connexins was predominantly confined to the endothelial cells. We found a significantly increased abundance (240 +/- 17.6%, p<0.05) of Cx37 in arterioles from WKY compared with SD and SHR. This high abundance of Cx37 was not related to blood pressure because normotensive SD demonstrated a level of Cx37 similar to that of SHR. Additionally, we found no evidence for an increased abundance of Cx40 and Cx43 in renal arterioles of SHR when compared with normotensive counterparts.
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Affiliation(s)
- Thomas Hartig Braunstein
- Danish National Research Foundation Center for Cardiac Arrhythmia Research, Division of Renal and Microvascular Research, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen, Denmark
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