1
|
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.
Collapse
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
| |
Collapse
|
2
|
Abstract
Resistance arteries and arterioles evolved as specialized blood vessels serving two important functions: (a) regulating peripheral vascular resistance and blood pressure and (b) matching oxygen and nutrient delivery to metabolic demands of organs. These functions require control of vessel lumen cross-sectional area (vascular tone) via coordinated vascular cell responses governed by precise spatial-temporal communication between intracellular signaling pathways. Herein, we provide a contemporary overview of the significant roles that redox switches play in calcium signaling for orchestrated endothelial, smooth muscle, and red blood cell control of arterial vascular tone. Three interrelated themes are the focus: (a) smooth muscle to endothelial communication for vasoconstriction, (b) endothelial to smooth muscle cell cross talk for vasodilation, and (c) oxygen and red blood cell interregulation of vascular tone and blood flow. We intend for this thematic framework to highlight gaps in our current knowledge and potentially spark interest for cross-disciplinary studies moving forward.
Collapse
Affiliation(s)
- Máté Katona
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA;
| | - Mark T Gladwin
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA;
- Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Current affiliation: University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Adam C Straub
- Pittsburgh Heart, Lung, and Blood Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA;
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Center for Microvascular Research, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
King DR, Sedovy MW, Eaton X, Dunaway LS, Good ME, Isakson BE, Johnstone SR. Cell-To-Cell Communication in the Resistance Vasculature. Compr Physiol 2022; 12:3833-3867. [PMID: 35959755 DOI: 10.1002/cphy.c210040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.
Collapse
Affiliation(s)
- D Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Meghan W Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, Virginia, USA
| | - Xinyan Eaton
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Luke S Dunaway
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Miranda E Good
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Scott R Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| |
Collapse
|
5
|
Garland CJ, Dora KA. Endothelium-Dependent Hyperpolarization: The Evolution of Myoendothelial Microdomains. J Cardiovasc Pharmacol 2021; 78:S3-S12. [PMID: 34840265 DOI: 10.1097/fjc.0000000000001087] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 05/29/2021] [Indexed: 10/19/2022]
Abstract
ABSTRACT Endothelium-derived hyperpolarizing factor (EDHF) was envisaged as a chemical entity causing vasodilation by hyperpolarizing vascular smooth muscle (VSM) cells and distinct from nitric oxide (NO) ([aka endothelium-derived relaxing factor (EDRF)]) and prostacyclin. The search for an identity for EDHF unraveled the complexity of signaling within small arteries. Hyperpolarization originates within endothelial cells (ECs), spreading to the VSM by 2 branches, 1 chemical and 1 electrical, with the relative contribution varying with artery location, branch order, and prevailing profile of VSM activation. Chemical signals vary likewise and can involve potassium ion, lipid mediators, and hydrogen peroxide, whereas electrical signaling depends on physical contacts formed by homocellular and heterocellular (myoendothelial; MEJ) gap junctions, both able to conduct hyperpolarizing current. The discovery that chemical and electrical signals each arise within ECs resulted in an evolution of the single EDHF concept into the more inclusive, EDH signaling. Recognition of the importance of MEJs and particularly the fact they can support bidirectional signaling also informed the discovery that Ca2+ signals can pass from VSM to ECs during vasoconstriction. This signaling activates negative feedback mediated by NO and EDH forming a myoendothelial feedback circuit, which may also be responsible for basal or constitutive release of NO and EDH activity. The MEJs are housed in endothelial projections, and another spin-off from investigating EDH signaling was the discovery these fine structures contain clusters of signaling proteins to regulate both hyperpolarization and NO release. So, these tiny membrane bridges serve as a signaling superhighway or infobahn, which controls vasoreactivity by responding to signals flowing back and forth between the endothelium and VSM. By allowing bidirectional signaling, MEJs enable sinusoidal vasomotion, co-ordinated cycles of widespread vasoconstriction/vasodilation that optimize time-averaged blood flow. Cardiovascular disease disrupts EC signaling and as a result vasomotion changes to vasospasm.
Collapse
|
6
|
Jackson WF. Calcium-Dependent Ion Channels and the Regulation of Arteriolar Myogenic Tone. Front Physiol 2021; 12:770450. [PMID: 34819877 PMCID: PMC8607693 DOI: 10.3389/fphys.2021.770450] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/11/2021] [Indexed: 11/25/2022] Open
Abstract
Arterioles in the peripheral microcirculation regulate blood flow to and within tissues and organs, control capillary blood pressure and microvascular fluid exchange, govern peripheral vascular resistance, and contribute to the regulation of blood pressure. These important microvessels display pressure-dependent myogenic tone, the steady state level of contractile activity of vascular smooth muscle cells (VSMCs) that sets resting arteriolar internal diameter such that arterioles can both dilate and constrict to meet the blood flow and pressure needs of the tissues and organs that they perfuse. This perspective will focus on the Ca2+-dependent ion channels in the plasma and endoplasmic reticulum membranes of arteriolar VSMCs and endothelial cells (ECs) that regulate arteriolar tone. In VSMCs, Ca2+-dependent negative feedback regulation of myogenic tone is mediated by Ca2+-activated K+ (BKCa) channels and also Ca2+-dependent inactivation of voltage-gated Ca2+ channels (VGCC). Transient receptor potential subfamily M, member 4 channels (TRPM4); Ca2+-activated Cl− channels (CaCCs; TMEM16A/ANO1), Ca2+-dependent inhibition of voltage-gated K+ (KV) and ATP-sensitive K+ (KATP) channels; and Ca2+-induced-Ca2+ release through inositol 1,4,5-trisphosphate receptors (IP3Rs) participate in Ca2+-dependent positive-feedback regulation of myogenic tone. Calcium release from VSMC ryanodine receptors (RyRs) provide negative-feedback through Ca2+-spark-mediated control of BKCa channel activity, or positive-feedback regulation in cooperation with IP3Rs or CaCCs. In some arterioles, VSMC RyRs are silent. In ECs, transient receptor potential vanilloid subfamily, member 4 (TRPV4) channels produce Ca2+ sparklets that activate IP3Rs and intermediate and small conductance Ca2+ activated K+ (IKCa and sKCa) channels causing membrane hyperpolarization that is conducted to overlying VSMCs producing endothelium-dependent hyperpolarization and vasodilation. Endothelial IP3Rs produce Ca2+ pulsars, Ca2+ wavelets, Ca2+ waves and increased global Ca2+ levels activating EC sKCa and IKCa channels and causing Ca2+-dependent production of endothelial vasodilator autacoids such as NO, prostaglandin I2 and epoxides of arachidonic acid that mediate negative-feedback regulation of myogenic tone. Thus, Ca2+-dependent ion channels importantly contribute to many aspects of the regulation of myogenic tone in arterioles in the microcirculation.
Collapse
Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
7
|
Aramide Modupe Dosunmu-Ogunbi A, Galley JC, Yuan S, Schmidt HM, Wood KC, Straub AC. Redox Switches Controlling Nitric Oxide Signaling in the Resistance Vasculature and Implications for Blood Pressure Regulation: Mid-Career Award for Research Excellence 2020. Hypertension 2021; 78:912-926. [PMID: 34420371 DOI: 10.1161/hypertensionaha.121.16493] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The arterial resistance vasculature modulates blood pressure and flow to match oxygen delivery to tissue metabolic demand. As such, resistance arteries and arterioles have evolved a series of highly orchestrated cell-cell communication mechanisms between endothelial cells and vascular smooth muscle cells to regulate vascular tone. In response to neurohormonal agonists, release of several intracellular molecules, including nitric oxide, evokes changes in vascular tone. We and others have uncovered novel redox switches in the walls of resistance arteries that govern nitric oxide compartmentalization and diffusion. In this review, we discuss our current understanding of redox switches controlling nitric oxide signaling in endothelial and vascular smooth muscle cells, focusing on new mechanistic insights, physiological and pathophysiological implications, and advances in therapeutic strategies for hypertension and other diseases.
Collapse
Affiliation(s)
- Atinuke Aramide Modupe Dosunmu-Ogunbi
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA.,Department of Pharmacology and Chemical Biology (A.A.M.D.-O., J.C.G., H.M.S., A.C.S), University of Pittsburgh, PA
| | - Joseph C Galley
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA.,Department of Pharmacology and Chemical Biology (A.A.M.D.-O., J.C.G., H.M.S., A.C.S), University of Pittsburgh, PA
| | - Shuai Yuan
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA
| | - Heidi M Schmidt
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA.,Department of Pharmacology and Chemical Biology (A.A.M.D.-O., J.C.G., H.M.S., A.C.S), University of Pittsburgh, PA
| | - Katherine C Wood
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute (A.A.M.D.-O., J.C.G., S.Y., H.M.S., K.C.W., A.C.S.), University of Pittsburgh, PA.,Department of Pharmacology and Chemical Biology (A.A.M.D.-O., J.C.G., H.M.S., A.C.S), University of Pittsburgh, PA.,Center for Microvascular Research (A.C.S.), University of Pittsburgh, PA
| |
Collapse
|
8
|
Cellular Crosstalk between Endothelial and Smooth Muscle Cells in Vascular Wall Remodeling. Int J Mol Sci 2021; 22:ijms22147284. [PMID: 34298897 PMCID: PMC8306829 DOI: 10.3390/ijms22147284] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/25/2021] [Accepted: 07/01/2021] [Indexed: 12/24/2022] Open
Abstract
Pathological vascular wall remodeling refers to the structural and functional changes of the vessel wall that occur in response to injury that eventually leads to cardiovascular disease (CVD). Vessel wall are composed of two major primary cells types, endothelial cells (EC) and vascular smooth muscle cells (VSMCs). The physiological communications between these two cell types (EC–VSMCs) are crucial in the development of the vasculature and in the homeostasis of mature vessels. Moreover, aberrant EC–VSMCs communication has been associated to the promotor of various disease states including vascular wall remodeling. Paracrine regulations by bioactive molecules, communication via direct contact (junctions) or information transfer via extracellular vesicles or extracellular matrix are main crosstalk mechanisms. Identification of the nature of this EC–VSMCs crosstalk may offer strategies to develop new insights for prevention and treatment of disease that curse with vascular remodeling. Here, we will review the molecular mechanisms underlying the interplay between EC and VSMCs. Additionally, we highlight the potential applicable methodologies of the co-culture systems to identify cellular and molecular mechanisms involved in pathological vascular wall remodeling, opening questions about the future research directions.
Collapse
|
9
|
Martins-Marques T, Rodriguez-Sinovas A, Girao H. Cellular crosstalk in cardioprotection: Where and when do reactive oxygen species play a role? Free Radic Biol Med 2021; 169:397-409. [PMID: 33892116 DOI: 10.1016/j.freeradbiomed.2021.03.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/14/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022]
Abstract
A well-balanced intercellular communication between the different cells within the heart is vital for the maintenance of cardiac homeostasis and function. Despite remarkable advances on disease management and treatment, acute myocardial infarction remains the major cause of morbidity and mortality worldwide. Gold standard reperfusion strategies, namely primary percutaneous coronary intervention, are crucial to preserve heart function. However, reestablishment of blood flow and oxygen levels to the infarcted area are also associated with an accumulation of reactive oxygen species (ROS), leading to oxidative damage and cardiomyocyte death, a phenomenon termed myocardial reperfusion injury. In addition, ROS signaling has been demonstrated to regulate multiple biological pathways, including cell differentiation and intercellular communication. Given the importance of cell-cell crosstalk in the coordinated response after cell injury, in this review, we will discuss the impact of ROS in the different forms of inter- and intracellular communication, as well as the role of gap junctions, tunneling nanotubes and extracellular vesicles in the propagation of oxidative damage in cardiac diseases, particularly in the context of ischemia/reperfusion injury.
Collapse
Affiliation(s)
- Tania Martins-Marques
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal; Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal; Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Antonio Rodriguez-Sinovas
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall D'Hebron Institut de Recerca (VHIR), Vall D'Hebron Hospital Universitari, Vall D'Hebron Barcelona Hospital Campus, Passeig Vall D'Hebron, 119-129, 08035, Barcelona, Spain; Departament de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain; Centro de Investigación Biomédica en Red Sobre Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Henrique Girao
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal; Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal; Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal.
| |
Collapse
|
10
|
Wolpe AG, Ruddiman CA, Hall PJ, Isakson BE. Polarized Proteins in Endothelium and Their Contribution to Function. J Vasc Res 2021; 58:65-91. [PMID: 33503620 DOI: 10.1159/000512618] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/27/2020] [Indexed: 12/11/2022] Open
Abstract
Protein localization in endothelial cells is tightly regulated to create distinct signaling domains within their tight spatial restrictions including luminal membranes, abluminal membranes, and interendothelial junctions, as well as caveolae and calcium signaling domains. Protein localization in endothelial cells is also determined in part by the vascular bed, with differences between arteries and veins and between large and small arteries. Specific protein polarity and localization is essential for endothelial cells in responding to various extracellular stimuli. In this review, we examine protein localization in the endothelium of resistance arteries, with occasional references to other vessels for contrast, and how that polarization contributes to endothelial function and ultimately whole organism physiology. We highlight the protein localization on the luminal surface, discussing important physiological receptors and the glycocalyx. The protein polarization to the abluminal membrane is especially unique in small resistance arteries with the presence of the myoendothelial junction, a signaling microdomain that regulates vasodilation, feedback to smooth muscle cells, and ultimately total peripheral resistance. We also discuss the interendothelial junction, where tight junctions, adherens junctions, and gap junctions all convene and regulate endothelial function. Finally, we address planar cell polarity, or axial polarity, and how this is regulated by mechanosensory signals like blood flow.
Collapse
Affiliation(s)
- Abigail G Wolpe
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Claire A Ruddiman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Phillip J Hall
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA, .,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA,
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Kumar G, Dey SK, Kundu S. Functional implications of vascular endothelium in regulation of endothelial nitric oxide synthesis to control blood pressure and cardiac functions. Life Sci 2020; 259:118377. [PMID: 32898526 DOI: 10.1016/j.lfs.2020.118377] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 08/24/2020] [Accepted: 08/31/2020] [Indexed: 11/29/2022]
Abstract
The endothelium is the innermost vascular lining performing significant roles all over the human body while maintaining the blood pressure at physiological levels. Malfunction of endothelium is thus recognized as a biomarker linked with many vascular diseases including but not limited to atherosclerosis, hypertension and thrombosis. Alternatively, prevention of endothelial malfunctioning or regulating the functions of its associated physiological partners like endothelial nitric oxide synthase can prevent the associated vascular disorders which account for the highest death toll worldwide. While many anti-hypertensive drugs are available commercially, a comprehensive description of the key physiological roles of the endothelium and its regulation by endothelial nitric oxide synthase or vice versa is the need of the hour to understand its contribution in vascular homeostasis. This, in turn, will help in designing new therapeutics targeting endothelial nitric oxide synthase or its interacting partners present in the cellular pool. This review describes the central role of vascular endothelium in the regulation of endothelial nitric oxide synthase while outlining the emerging drug targets present in the vasculature with potential to treat vascular disorders including hypertension.
Collapse
Affiliation(s)
- Gaurav Kumar
- Department of Biochemistry, University of Delhi, South Campus, New Delhi 110021, India
| | - Sanjay Kumar Dey
- Department of Biochemistry, University of Delhi, South Campus, New Delhi 110021, India; Center for Advanced Biotechnology and Medicine, Rutgers University, NJ 08854, USA
| | - Suman Kundu
- Department of Biochemistry, University of Delhi, South Campus, New Delhi 110021, India.
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Lemmey HAL, Garland CJ, Dora KA. Intrinsic regulation of microvascular tone by myoendothelial feedback circuits. CURRENT TOPICS IN MEMBRANES 2020; 85:327-355. [PMID: 32402644 DOI: 10.1016/bs.ctm.2020.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The endothelium is an important regulator of arterial vascular tone, acting to release nitric oxide (NO) and open Ca2+-activated K+ (KCa) channels to relax vascular smooth muscle cells (VSMCs). While agonists acting at endothelial cell (EC) receptors are widely used to assess the ability of the endothelium to reduce vascular tone, the intrinsic EC-dependent mechanisms are less well characterized. In small resistance arteries and arterioles, the presence of heterocellular gap junctions termed myoendothelial gap junctions (MEGJs) allows the passage of not only current, but small molecules including Ca2+ and inositol trisphosphate (IP3). When stimulated to contract, the increase in VSM Ca2+ and IP3 can therefore potentially pass through MEGJs to activate adjacent ECs. This activation releases NO and opens KCa channels, which act to limit contraction. This myoendothelial feedback (MEF) is amplified by EC Ca2+ influx and release pathways, and is dynamically modulated by processes regulating gap junction conductance. There is a remarkable localization of key signaling and regulatory proteins within the EC projection toward VSM, and the intrinsic EC-dependent signaling pathways occurring with this highly specialized microdomain are reviewed.
Collapse
Affiliation(s)
- Hamish A L Lemmey
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | | | - Kim A Dora
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
15
|
Cellular microdomains for nitric oxide signaling in endothelium and red blood cells. Nitric Oxide 2020; 96:44-53. [PMID: 31911123 DOI: 10.1016/j.niox.2020.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/23/2019] [Accepted: 01/02/2020] [Indexed: 12/13/2022]
Abstract
There is accumulating evidence that biological membranes are not just homogenous lipid structures, but are highly organized in microdomains, i.e. compartmentalized areas of protein and lipid complexes, which facilitate necessary interactions for various signaling pathways. Each microdomain exhibits unique composition, membrane location and dynamics, which ultimately shape their functional characteristics. In the vasculature, microdomains are crucial for organizing and compartmentalizing vasodilatory signals that contribute to blood pressure homeostasis. In this review we aim to describe how membrane microdomains in both the endothelium and red blood cells allow context-specific regulation of the vasodilatory signal nitric oxide (NO) and its corresponding metabolic products, and how this results in tightly controlled systemic physiological responses. We will describe (1) structural characteristics of microdomains including lipid rafts and caveolae; (2) endothelial cell caveolae and how they participate in mechanosensing and NO-dependent mechanotransduction; (3) the myoendothelial junction of resistance arterial endothelial cells and how protein-protein interactions within it have profound systemic effects on blood pressure regulation, and (4) putative/proposed NO microdomains in RBCs and how they participate in control of systemic NO bioavailability. The sum of these discussions will provide a current view of NO regulation by cellular microdomains.
Collapse
|
16
|
Endothelial Ca 2+ Signaling, Angiogenesis and Vasculogenesis: just What It Takes to Make a Blood Vessel. Int J Mol Sci 2019; 20:ijms20163962. [PMID: 31416282 PMCID: PMC6721072 DOI: 10.3390/ijms20163962] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022] Open
Abstract
It has long been known that endothelial Ca2+ signals drive angiogenesis by recruiting multiple Ca2+-sensitive decoders in response to pro-angiogenic cues, such as vascular endothelial growth factor, basic fibroblast growth factor, stromal derived factor-1α and angiopoietins. Recently, it was shown that intracellular Ca2+ signaling also drives vasculogenesis by stimulation proliferation, tube formation and neovessel formation in endothelial progenitor cells. Herein, we survey how growth factors, chemokines and angiogenic modulators use endothelial Ca2+ signaling to regulate angiogenesis and vasculogenesis. The endothelial Ca2+ response to pro-angiogenic cues may adopt different waveforms, ranging from Ca2+ transients or biphasic Ca2+ signals to repetitive Ca2+ oscillations, and is mainly driven by endogenous Ca2+ release through inositol-1,4,5-trisphosphate receptors and by store-operated Ca2+ entry through Orai1 channels. Lysosomal Ca2+ release through nicotinic acid adenine dinucleotide phosphate-gated two-pore channels is, however, emerging as a crucial pro-angiogenic pathway, which sustains intracellular Ca2+ mobilization. Understanding how endothelial Ca2+ signaling regulates angiogenesis and vasculogenesis could shed light on alternative strategies to induce therapeutic angiogenesis or interfere with the aberrant vascularization featuring cancer and intraocular disorders.
Collapse
|
17
|
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]
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Aasen T, Johnstone S, Vidal-Brime L, Lynn KS, Koval M. Connexins: Synthesis, Post-Translational Modifications, and Trafficking in Health and Disease. Int J Mol Sci 2018; 19:ijms19051296. [PMID: 29701678 PMCID: PMC5983588 DOI: 10.3390/ijms19051296] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 02/06/2023] Open
Abstract
Connexins are tetraspan transmembrane proteins that form gap junctions and facilitate direct intercellular communication, a critical feature for the development, function, and homeostasis of tissues and organs. In addition, a growing number of gap junction-independent functions are being ascribed to these proteins. The connexin gene family is under extensive regulation at the transcriptional and post-transcriptional level, and undergoes numerous modifications at the protein level, including phosphorylation, which ultimately affects their trafficking, stability, and function. Here, we summarize these key regulatory events, with emphasis on how these affect connexin multifunctionality in health and disease.
Collapse
Affiliation(s)
- Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - Scott Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VI 22908, USA.
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, UK.
| | - Laia Vidal-Brime
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - K Sabrina Lynn
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
20
|
Biwer LA, Good ME, Hong K, Patel RK, Agrawal N, Looft-Wilson R, Sonkusare SK, Isakson BE. Non-Endoplasmic Reticulum-Based Calr (Calreticulin) Can Coordinate Heterocellular Calcium Signaling and Vascular Function. Arterioscler Thromb Vasc Biol 2018; 38:120-130. [PMID: 29122814 PMCID: PMC5746467 DOI: 10.1161/atvbaha.117.309886] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/25/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In resistance arteries, endothelial cell (EC) extensions can make contact with smooth muscle cells, forming myoendothelial junction at holes in the internal elastic lamina (HIEL). At these HIEL, calcium signaling is tightly regulated. Because Calr (calreticulin) can buffer ≈50% of endoplasmic reticulum calcium and is expressed throughout IEL holes in small arteries, the only place where myoendothelial junctions form, we investigated the effect of EC-specific Calr deletion on calcium signaling and vascular function. APPROACH AND RESULTS We found Calr expressed in nearly every IEL hole in third-order mesenteric arteries, but not other ER markers. Because of this, we generated an EC-specific, tamoxifen inducible, Calr knockout mouse (EC Calr Δ/Δ). Using this mouse, we tested third-order mesenteric arteries for changes in calcium events at HIEL and vascular reactivity after application of CCh (carbachol) or PE (phenylephrine). We found that arteries from EC Calr Δ/Δ mice stimulated with CCh had unchanged activity of calcium signals and vasodilation; however, the same arteries were unable to increase calcium events at HIEL in response to PE. This resulted in significantly increased vasoconstriction to PE, presumably because of inhibited negative feedback. In line with these observations, the EC Calr Δ/Δ had increased blood pressure. Comparison of ER calcium in arteries and use of an ER-specific GCaMP indicator in vitro revealed no observable difference in ER calcium with Calr knockout. Using selective detergent permeabilization of the artery and inhibition of Calr translocation, we found that the observed Calr at HIEL may not be within the ER. CONCLUSIONS Our data suggest that Calr specifically at HIEL may act in a non-ER dependent manner to regulate arteriolar heterocellular communication and blood pressure.
Collapse
Affiliation(s)
- Lauren A Biwer
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Miranda E Good
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Kwangseok Hong
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Rahul K Patel
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Neha Agrawal
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Robin Looft-Wilson
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Swapnil K Sonkusare
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.).
| |
Collapse
|
21
|
Pogoda K, Mannell H, Blodow S, Schneider H, Schubert KM, Qiu J, Schmidt A, Imhof A, Beck H, Tanase LI, Pfeifer A, Pohl U, Kameritsch P. NO Augments Endothelial Reactivity by Reducing Myoendothelial Calcium Signal Spreading: A Novel Role for Cx37 (Connexin 37) and the Protein Tyrosine Phosphatase SHP-2. Arterioscler Thromb Vasc Biol 2017; 37:2280-2290. [PMID: 29025706 DOI: 10.1161/atvbaha.117.309913] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 09/26/2017] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Because of its strategic position between endothelial and smooth muscle cells in microvessels, Cx37 (Connexin 37) plays an important role in myoendothelial gap junctional intercellular communication. We have shown before that NO inhibits gap junctional intercellular communication through gap junctions containing Cx37. However, the underlying mechanism is not yet identified. APPROACH AND RESULTS Using channel-forming Cx37 mutants exhibiting partial deletions or amino acid exchanges in their C-terminal loops, we now show that the phosphorylation state of a tyrosine residue at position 332 (Y332) in the C-terminus of Cx37 controls the gap junction-dependent spread of calcium signals. Mass spectra revealed that NO protects Cx37 from dephosphorylation at Y332 by inhibition of the protein tyrosine phosphatase SHP-2. Functionally, the inhibition of gap junctional intercellular communication by NO decreased the spread of the calcium signal (induced by mechanical stimulation of individual endothelial cells) from endothelial to smooth muscle cells in intact vessels, while, at the same time, augmenting the calcium signal spreading within the endothelium. Consequently, preincubation of small resistance arteries with exogenous NO enhanced the endothelium-dependent dilator response to acetylcholine in spite of a pharmacological blockade of NO-dependent cGMP formation by the soluable guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). CONCLUSIONS Our results identify a novel mechanism by which NO can increase the efficacy of calcium, rising vasoactive agonists in the microvascular endothelium.
Collapse
Affiliation(s)
- Kristin Pogoda
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Hanna Mannell
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Stephanie Blodow
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Holger Schneider
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Kai Michael Schubert
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Jiehua Qiu
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Andreas Schmidt
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Axel Imhof
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Heike Beck
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Laurentia Irina Tanase
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Alexander Pfeifer
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| | - Ulrich Pohl
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.).
| | - Petra Kameritsch
- From the Walter Brendel Centre of Experimental Medicine, University Hospital, Biomedical Center, Munich, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., L.I.T., U.P., P.K.); Protein Analysis Unit, Biomedical Center, Munich, Germany (A.S., A.I.); DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Germany (K.P., H.M., S.B., H.S., K.M.S., J.Q., H.B., U.P., P.K.); Munich Cluster for Systems Neurology (SyNergY), Germany (A.I., U.P.); and Institute of Pharmacology and Toxicology, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany (A.P.)
| |
Collapse
|
22
|
Biwer LA, Lechauve C, Vanhoose S, Weiss MJ, Isakson BE. A Cell Culture Model of Resistance Arteries. J Vis Exp 2017. [PMID: 28930992 DOI: 10.3791/55992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The myoendothelial junction (MEJ), a unique signaling microdomain in small diameter resistance arteries, exhibits localization of specific proteins and signaling processes that can control vascular tone and blood pressure. As it is a projection from either the endothelial or smooth muscle cell, and due to its small size (on average, an area of ~1 µm2), the MEJ is difficult to study in isolation. However, we have developed a cell culture model called the vascular cell co-culture (VCCC) that allows for in vitro MEJ formation, endothelial cell polarization, and dissection of signaling proteins and processes in the vascular wall of resistance arteries. The VCCC has a multitude of applications and can be adapted to suit different cell types. The model consists of two cell types grown on opposite sides of a filter with 0.4 µm pores in which the in vitro MEJs can form. Here we describe how to create the VCCC via plating of cells and isolation of endothelial, MEJ, and smooth muscle fractions, which can then be used for protein isolation or activity assays. The filter with intact cell layers can be fixed, embedded, and sectioned for immunofluorescent analysis. Importantly, many of the discoveries from this model have been confirmed using intact resistance arteries, underscoring its physiological relevance.
Collapse
Affiliation(s)
- Lauren A Biwer
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine
| | | | - Sheri Vanhoose
- Research Histology Core, University of Virginia School of Medicine
| | | | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine;
| |
Collapse
|
23
|
IP 3 receptor signaling and endothelial barrier function. Cell Mol Life Sci 2017; 74:4189-4207. [PMID: 28803370 DOI: 10.1007/s00018-017-2624-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/18/2017] [Accepted: 08/08/2017] [Indexed: 12/14/2022]
Abstract
The endothelium, a monolayer of endothelial cells lining vessel walls, maintains tissue-fluid homeostasis by restricting the passage of the plasma proteins and blood cells into the interstitium. The ion Ca2+, a ubiquitous secondary messenger, initiates signal transduction events in endothelial cells that is critical to control of vascular tone and endothelial permeability. The ion Ca2+ is stored inside the intracellular organelles and released into the cytosol in response to environmental cues. The inositol 1,4,5-trisphosphate (IP3) messenger facilitates Ca2+ release through IP3 receptors which are Ca2+-selective intracellular channels located within the membrane of the endoplasmic reticulum. Binding of IP3 to the IP3Rs initiates assembly of IP3R clusters, a key event responsible for amplification of Ca2+ signals in endothelial cells. This review discusses emerging concepts related to architecture and dynamics of IP3R clusters, and their specific role in propagation of Ca2+ signals in endothelial cells.
Collapse
|
24
|
Garland CJ, Bagher P, Powell C, Ye X, Lemmey HAL, Borysova L, Dora KA. Voltage-dependent Ca 2+ entry into smooth muscle during contraction promotes endothelium-mediated feedback vasodilation in arterioles. Sci Signal 2017; 10:10/486/eaal3806. [PMID: 28676489 DOI: 10.1126/scisignal.aal3806] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vascular smooth muscle contraction is suppressed by feedback dilation mediated by the endothelium. In skeletal muscle arterioles, this feedback can be activated by Ca2+ signals passing from smooth muscle through gap junctions to endothelial cells, which protrude through holes in the internal elastic lamina to make contact with vascular smooth muscle cells. Although hypothetically either Ca2+ or inositol trisphosphate (IP3) may provide the intercellular signal, it is generally thought that IP3 diffusion is responsible. We provide evidence that Ca2+ entry through L-type voltage-dependent Ca2+ channels (VDCCs) in vascular smooth muscle can pass to the endothelium through positions aligned with holes in the internal elastic lamina in amounts sufficient to activate endothelial cell Ca2+ signaling. In endothelial cells in which IP3 receptors (IP3Rs) were blocked, VDCC-driven Ca2+ events were transient and localized to the endothelium that protrudes through the internal elastic lamina to contact vascular smooth muscle cells. In endothelial cells in which IP3Rs were not blocked, VDCC-driven Ca2+ events in endothelial cells were amplified to form propagating waves. These waves activated voltage-insensitive, intermediate-conductance, Ca2+-activated K+ (IKCa) channels, thereby providing feedback that effectively suppressed vasoconstriction and enabled cycles of constriction and dilation called vasomotion. Thus, agonists that stimulate vascular smooth muscle depolarization provide Ca2+ to endothelial cells to activate a feedback circuit that protects tissue blood flow.
Collapse
Affiliation(s)
- Christopher J Garland
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Pooneh Bagher
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Chloe Powell
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Hamish A L Lemmey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Lyudmyla Borysova
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Kim A Dora
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| |
Collapse
|
25
|
Xu J, Yang G, Li T, Liu L. Myoendothelial gap junctions mediate regulation of angiopoietin-2-induced vascular hyporeactivity after hypoxia through connexin 43-gated cAMP transfer. Am J Physiol Cell Physiol 2017. [PMID: 28637680 DOI: 10.1152/ajpcell.00369.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Angiopoietin-2 (Ang-2) contributes to vascular hyporeactivity after hemorrhagic shock and hypoxia through upregulation of inducible nitric oxide synthase (iNOS) in a vascular endothelial cell (VEC)-specific and Ang-2/Tie2 receptor-dependent manner. While iNOS is primarily expressed in vascular smooth muscle cells (VSMCs), the mechanisms of signal transfer from VECs to VSMCs are unknown. A double-sided coculture model with VECs and VSMCs from Sprague-Dawley rats was used to investigate the role of myoendothelial gap junctions (MEGJs), the connexin (Cx) isoforms involved, and other relevant mechanisms. After hypoxia, VSMCs treated with exogenous Ang-2 showed increased iNOS expression and hyporeactivity, as well as MEGJ formation and communication. These Ang-2 effects were suppressed by the MEGJ inhibitor 18α-glycyrrhetic acid (18-GA), Tie2 siRNA, or Cx43 siRNA. Reagents antagonizing cAMP or protein kinase A (PKA) in VECs inhibited Cx43 expression in MEGJs, decreasing MEGJ formation and associated communication, after hypoxia following Ang-2 treatment. The increased cAMP levels in VSMCs and transfer of Alexa Fluor 488-labeled cAMP from VECs to VSMCs, after hypoxia following Ang-2 treatment, was antagonized by Cx43 siRNA. A cAMP antagonist added to VECs or VSMCs inhibited both increased iNOS expression and hyporeactivity in VSMCs subjected to hypoxia following Ang-2 treatment. Based on these findings, we propose that Cx43 was the Cx isoform involved in MEGJ-mediated VEC-dependent regulation of Ang-2, which induces iNOS protein expression and vascular hyporeactivity after hypoxia. Cx43 was upregulated by cAMP and PKA, permitting cAMP transfer between cells.
Collapse
Affiliation(s)
- Jing Xu
- State Key Laboratory of Trauma, Burns and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Guangming Yang
- State Key Laboratory of Trauma, Burns and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Tao Li
- State Key Laboratory of Trauma, Burns and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Liangming Liu
- State Key Laboratory of Trauma, Burns and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| |
Collapse
|
26
|
Abstract
SIGNIFICANCE The family of gasotransmitter molecules, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S), has emerged as an important mediator of numerous cellular signal transduction and pathophysiological responses. As such, these molecules have been reported to influence a diverse array of biochemical, molecular, and cell biology events often impacting one another. Recent Advances: Discrete regulation of gasotransmitter molecule formation, movement, and reaction is critical to their biological function. Due to the chemical nature of these molecules, they can move rapidly throughout cells and tissues acting on targets through reactions with metal groups, reactive chemical species, and protein amino acids. CRITICAL ISSUES Given the breadth and complexity of gasotransmitter reactions, this field of research is expanding into exciting, yet sometimes confusing, areas of study with significant promise for understanding health and disease. The precise amounts of tissue and cellular gasotransmitter levels and where they are formed, as well as how they react with molecular targets or themselves, all remain poorly understood. FUTURE DIRECTIONS Elucidation of specific molecular targets, characteristics of gasotransmitter molecule heterotypic interactions, and spatiotemporal formation and metabolism are all important to better understand their true pathophysiological importance in various organ systems. Antioxid. Redox Signal. 26, 936-960.
Collapse
Affiliation(s)
- Gopi K Kolluru
- 1 Department of Pathology, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana
| | - Xinggui Shen
- 1 Department of Pathology, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana
| | - Shuai Yuan
- 2 Department of Cellular Biology and Anatomy, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana
| | - Christopher G Kevil
- 1 Department of Pathology, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana.,2 Department of Cellular Biology and Anatomy, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana.,3 Department of Molecular and Cellular Physiology, LSU Health Sciences Center-Shreveport , Shreveport, Louisiana
| |
Collapse
|
27
|
Parikh J, Kapela A, Tsoukias NM. Can endothelial hemoglobin-α regulate nitric oxide vasodilatory signaling? Am J Physiol Heart Circ Physiol 2017; 312:H854-H866. [PMID: 28130333 DOI: 10.1152/ajpheart.00315.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 11/22/2022]
Abstract
We used mathematical modeling to investigate nitric oxide (NO)-dependent vasodilatory signaling in the arteriolar wall. Detailed continuum cellular models of calcium (Ca2+) dynamics and membrane electrophysiology in smooth muscle and endothelial cells (EC) were coupled with models of NO signaling and biotransport in an arteriole. We used this theoretical approach to examine the role of endothelial hemoglobin-α (Hbα) as a modulator of NO-mediated myoendothelial feedback, as previously suggested in Straub et al. (Nature 491: 473-477, 2012). The model considers enriched expression of inositol 1,4,5-triphosphate receptors (IP3Rs), endothelial nitric oxide synthase (eNOS) enzyme, Ca2+-activated potassium (KCa) channels and Hbα in myoendothelial projections (MPs) between the two cell layers. The model suggests that NO-mediated myoendothelial feedback is plausible if a significant percentage of eNOS is localized within or near the myoendothelial projection. Model results show that the ability of Hbα to regulate the myoendothelial feedback is conditional to its colocalization with eNOS near MPs at concentrations in the high nanomolar range (>0.2 μM or 24,000 molecules). Simulations also show that the effect of Hbα observed in in vitro experimental studies may overestimate its contribution in vivo, in the presence of blood perfusion. Thus, additional experimentation is required to quantify the presence and spatial distribution of Hbα in the EC, as well as to test that the strong effect of Hbα on NO signaling seen in vitro, translates also into a physiologically relevant response in vivo.NEW & NOTEWORTHY Mathematical modeling shows that although regulation of nitric oxide signaling by hemoglobin-α (Hbα) is plausible, it is conditional to its presence in significant concentrations colocalized with endothelial nitric oxide synthase in myoendothelial projections. Additional experimentation is required to test that the strong effect of Hbα seen in vitro translates into a physiologically relevant response in vivo.
Collapse
Affiliation(s)
- Jaimit Parikh
- Department of Biomedical Engineering, Florida International University, Miami, Florida; and
| | - Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, Florida; and
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, Florida; and .,School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| |
Collapse
|
28
|
Biwer LA, Isakson BE. Endoplasmic reticulum-mediated signalling in cellular microdomains. Acta Physiol (Oxf) 2017; 219:162-175. [PMID: 26973141 DOI: 10.1111/apha.12675] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/01/2015] [Accepted: 03/01/2016] [Indexed: 12/17/2022]
Abstract
The endoplasmic reticulum (ER) is a prime mediator of cellular signalling due to its functions as an internal cellular store for calcium, as well as a site for synthesis of proteins and lipids. Its peripheral network of sheets and tubules facilitates calcium and lipid signalling, especially in areas of the cell that are more distant to the main cytoplasmic network. Specific membrane proteins shape the peripheral ER architecture and influence the network stability to project into restricted spaces. The signalling microdomains are anatomically separate from the cytoplasm as a whole and exhibit localized protein, ion channel and cytoskeletal element expression. Signalling can also occur between the ER and other organelles, such as the Golgi or mitochondria. Lipids made in the ER membrane can be sent to the Golgi via specialized transfer proteins and specific phospholipid synthases are enriched at ER-mitochondria junctions to more efficiently expedite phospholipid transfer. As a hub for protein and lipid synthesis, a store for intracellular calcium [Ca2+ ]i and a mediator of cellular stress, the ER is an important cellular organelle. Its ability to organize into tubules and project into restricted spaces allows for discrete and temporal signalling, which is important for cellular physiology and organism homoeostasis.
Collapse
Affiliation(s)
- L. A. Biwer
- Department of Molecular Physiology and Biophysics; University of Virginia; Charlottesville VA USA
- Robert M. Berne Cardiovascular Research Center; University of Virginia School of Medicine; Charlottesville VA USA
| | - B. E. Isakson
- Department of Molecular Physiology and Biophysics; University of Virginia; Charlottesville VA USA
- Robert M. Berne Cardiovascular Research Center; University of Virginia School of Medicine; Charlottesville VA USA
| |
Collapse
|
29
|
Hearon CM, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Endothelium-dependent vasodilatory signalling modulates α 1 -adrenergic vasoconstriction in contracting skeletal muscle of humans. J Physiol 2016; 594:7435-7453. [PMID: 27561916 DOI: 10.1113/jp272829] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS 'Functional sympatholysis' describes the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction, and is critical to ensure proper blood flow and oxygen delivery to metabolically active skeletal muscle. The signalling mechanism responsible for sympatholysis in healthy humans is unknown. Evidence from animal models has identified endothelium-derived hyperpolarization (EDH) as a potential mechanism capable of attenuating sympathetic vasoconstriction. In this study, increasing endothelium-dependent signalling during exercise significantly enhanced the ability of contracting skeletal muscle to attenuate sympathetic vasoconstriction in humans. This is the first study in humans to identify endothelium-dependent regulation of sympathetic vasoconstriction in contracting skeletal muscle, and specifically supports a role for EDH-like vasodilatory signalling. Impaired functional sympatholysis is a common feature of cardiovascular ageing, hypertension and heart failure, and thus identifying fundamental mechanisms responsible for sympatholysis is clinically relevant. ABSTRACT Stimulation of α-adrenoceptors elicits vasoconstriction in resting skeletal muscle that is blunted during exercise in an intensity-dependent manner. In humans, the underlying mechanisms remain unclear. We tested the hypothesis that stimulating endothelium-dependent vasodilatory signalling will enhance the ability of contracting skeletal muscle to blunt α1 -adrenergic vasoconstriction. Changes in forearm vascular conductance (FVC; Doppler ultrasound, brachial intra-arterial pressure via catheter) to local intra-arterial infusion of phenylephrine (PE; α1 -adrenoceptor agonist) were calculated during (1) infusion of the endothelium-dependent vasodilators acetylcholine (ACh) and adenosine triphosphate (ATP), the endothelium-independent vasodilator (sodium nitroprusside, SNP), or potassium chloride (KCl) at rest; (2) mild or moderate intensity handgrip exercise; and (3) combined mild exercise + ACh, ATP, SNP, or KCl infusions in healthy adults. Robust vasoconstriction to PE was observed during vasodilator infusion alone and mild exercise, and this was blunted during moderate intensity exercise (ΔFVC: -34 ± 4 and -34 ± 3 vs. -13 ± 2%, respectively, P < 0.05). Infusion of ACh or ATP during mild exercise significantly attenuated PE vasoconstriction similar to levels observed during moderate exercise (ACh: -3 ± 4; ATP: -18 ± 4%). In contrast, infusion of SNP or KCl during mild exercise did not attenuate PE-mediated vasoconstriction (-32 ± 5 and -46 ± 3%). To further study the role of endothelium-dependent hyperpolarization (EDH), ACh trials were repeated with combined nitric oxide synthase and cyclooxygenase inhibition. Here, PE-mediated vasoconstriction was blunted at rest (blockade: -20 ± 5 vs. CONTROL -31 ± 3% vs.; P < 0.05) and remained blunted during exercise (blockade: -15 ± 5 vs. CONTROL -14 ± 5%). We conclude that stimulation of EDH-like vasodilatation can blunt α1 -adrenergic vasoconstriction in contracting skeletal muscle of humans.
Collapse
Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Brett S Kirby
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health System, Loveland, CO, 80538, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
| |
Collapse
|
30
|
Biwer LA, Taddeo EP, Kenwood BM, Hoehn KL, Straub AC, Isakson BE. Two functionally distinct pools of eNOS in endothelium are facilitated by myoendothelial junction lipid composition. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1861:671-9. [PMID: 27106139 PMCID: PMC4869716 DOI: 10.1016/j.bbalip.2016.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 03/10/2016] [Accepted: 04/16/2016] [Indexed: 12/21/2022]
Abstract
In resistance arteries, endothelial cells (EC) make contact with smooth muscle cells (SMC), forming myoendothelial junctions (MEJ). Endothelial nitric oxide synthase (eNOS) is present in the luminal side of the EC (apical EC) and the basal side of the EC (MEJ). To test if these eNOS pools acted in sync or separately, we co-cultured ECs and SMCs, then stimulated SMCs with phenylephrine (PE). Adrenergic activation causes inositol [1,4,5] triphosphate (IP3) to move from SMC to EC through gap junctions at the MEJ. PE increases MEJ eNOS phosphorylation (eNOS-P) at S1177, but not in EC. Conversely, we used bradykinin (BK) to increase EC calcium; this increased EC eNOS-P but did not affect MEJ eNOS-P. Inhibiting gap junctions abrogated the MEJ eNOS-P after PE, but had no effect on BK eNOS-P. Differential lipid composition between apical EC and MEJ may account for the compartmentalized eNOS-P response. Indeed, DAG and phosphatidylserine are both enriched in MEJ. These lipids are cofactors for PKC activity, which was significantly increased at the MEJ after PE. Because PKC activity also relies on endoplasmic reticulum (ER) calcium release, we used thapsigargin and xestospongin C, BAPTA, and PKC inhibitors, which caused significant decreases in MEJ eNOS-P after PE. Functionally, BK inhibited leukocyte adhesion and PE caused an increase in SMC cGMP. We hypothesize that local lipid composition of the MEJ primes PKC and eNOS-P for stimulation by PE, allowing for compartmentalized function of eNOS in the blood vessel wall.
Collapse
Affiliation(s)
- Lauren A Biwer
- Department of Molecular Physiology and Biophysics, University of Virginia, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, USA
| | - Evan P Taddeo
- Department of Pharmacology, University of Virginia, USA
| | | | - Kyle L Hoehn
- Department of Pharmacology, University of Virginia, USA; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Australia
| | - Adam C Straub
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, USA; Heart, Lung, Blood and Vascular Medicine Institute; University of Pittsburgh, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, USA.
| |
Collapse
|
31
|
Stochastic model of endothelial TRPV4 calcium sparklets: effect of bursting and cooperativity on EDH. Biophys J 2016; 108:1566-1576. [PMID: 25809269 DOI: 10.1016/j.bpj.2015.01.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/15/2015] [Accepted: 01/27/2015] [Indexed: 01/28/2023] Open
Abstract
We examined the endothelial transient receptor vanilloid 4 (TRPV4) channel's vasodilatory signaling using mathematical modeling. The model analyzes experimental data by Sonkusare and coworkers on TRPV4-induced endothelial Ca(2+) events (sparklets). A previously developed continuum model of an endothelial and a smooth muscle cell coupled through microprojections was extended to account for the activity of a TRPV4 channel cluster. Different stochastic descriptions for the TRPV4 channel flux were examined using finite-state Markov chains. The model also took into consideration recent evidence for the colocalization of intermediate-conductance calcium-activated potassium channels (IKCa) and TRPV4 channels near the microprojections. A single TRPV4 channel opening resulted in a stochastic localized Ca(2+) increase in a small region (i.e., few μm(2) area) close to the channel. We predict micromolar Ca(2+) increases lasting for the open duration of the channel sufficient for the activation of low-affinity endothelial KCa channels. Simulations of a cluster of four TRPV4 channels incorporating burst and cooperative gating kinetics provided quantal Ca(2+) increases (i.e., steps of fixed amplitude), similar to the experimentally observed Ca(2+) sparklets. These localized Ca(2+) events result in endothelium-derived hyperpolarization (and SMC relaxation), with magnitude that depends on event frequency. The gating characteristics (bursting, cooperativity) of the TRPV4 cluster enhance Ca(2+) spread and the distance of KCa channel activation. This may amplify the EDH response by the additional recruitment of distant KCa channels.
Collapse
|
32
|
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.
Collapse
|
33
|
Toussaint F, Charbel C, Blanchette A, Ledoux J. CaMKII regulates intracellular Ca²⁺ dynamics in native endothelial cells. Cell Calcium 2015; 58:275-85. [PMID: 26100947 DOI: 10.1016/j.ceca.2015.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 05/15/2015] [Accepted: 06/06/2015] [Indexed: 01/11/2023]
Abstract
Localized endothelial Ca(2+) signalling, such as Ca(2+) pulsars, can modulate the contractile state of the underlying vascular smooth muscle cell through specific endothelial targets. In addition to K(Ca)3.1 as a target, Ca(2+) pulsars, an IP3R-dependent pulsatile Ca(2+) release from the endoplasmic reticulum (ER) could activate a frequency-sensitive Ca(2+)-dependent kinase such as CaMKII. In the absence of extracellular Ca(2+), acetylcholine increased endothelial CaMKII phosphorylation and activation, thereby suggesting CaMKII activation independently of Ca(2+) influx. Herein, a reciprocal relation where CaMKII controls endothelial Ca(2+) dynamics has been investigated in mesenteric arteries. Both CaMKIIα and β isoforms have been identified in endothelial cells and close proximity (<40 nm) suggests their association in heteromultimers. Intracellular Ca(2+) monitoring with high speed confocal microscopy then showed that inhibition of CaMKII with KN-93 significantly increased the population of Ca(2+) pulsars active sites (+89%), suggesting CaMKII as a major regulator of Ca(2+) pulsars in native endothelium. Mechanistic insights were then sought through the elucidation of the impact of CaMKII on ER Ca(2+) store. ER Ca(2+) emptying was accelerated by CaMKII inhibition and ER Ca(2+) content was assessed using ionomycin. Exposure to KN-93 strongly diminished ER Ca(2+) content (-61%) by relieving CaMKII-dependent inhibition of IP3 receptors (IP3R). Moreover, in situ proximity ligation assay suggested CaMKII-IP3R promiscuity, essential condition for a protein-protein interaction. Interestingly, segregation of IP3R within myoendothelial projection (MEP) appears to be isoform-specific. Hence, only IP3R type 1 and type 2 are detected within fenestrations of the internal elastic lamina, sites of MEP, whilst type 3 is absent from these structures. In summary, CaMKII seems to act as a Ca(2+)-sensitive switch of a negative feedback loop regulating endothelial Ca(2+) homeostasis, including Ca(2+) pulsars.
Collapse
Affiliation(s)
- Fanny Toussaint
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Physiology, Université de Montréal, Québec, Canada
| | - Chimène Charbel
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Pharmacology, Université de Montréal, Québec, Canada
| | | | - Jonathan Ledoux
- Research Center, Montreal Heart Institute, Montréal, Québec, Canada; Department of Physiology, Université de Montréal, Québec, Canada; Department of Pharmacology, Université de Montréal, Québec, Canada; Department of Medicine, Université de Montréal, Québec, Canada.
| |
Collapse
|
34
|
Mutchler SM, Straub AC. Compartmentalized nitric oxide signaling in the resistance vasculature. Nitric Oxide 2015; 49:8-15. [PMID: 26028569 DOI: 10.1016/j.niox.2015.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/15/2015] [Accepted: 05/20/2015] [Indexed: 01/23/2023]
Abstract
Nitric oxide (NO) was first described as a bioactive molecule through its ability to stimulate soluble guanylate cyclase, but the revelation that NO was the endothelium derived relaxation factor drove the field to its modern state. The wealth of research conducted over the past 30 years has provided us with a picture of how diverse NO signaling can be within the vascular wall, going beyond simple vasodilation to include such roles as signaling through protein S-nitrosation. This expanded view of NO's actions requires highly regulated and compartmentalized production. Importantly, resistance arteries house multiple proteins involved in the production and transduction of NO allowing for efficient movement of the molecule to regulate vascular tone and reactivity. In this review, we focus on the many mechanisms regulating NO production and signaling action in the vascular wall, with a focus on the control of endothelial nitric oxide synthase (eNOS), the enzyme responsible for synthesizing most of the NO within these confines. We also explore how cross talk between the endothelium and smooth muscle in the microcirculation can modulate NO signaling, illustrating that this one small molecule has the capability to produce a plethora of responses.
Collapse
Affiliation(s)
- Stephanie M Mutchler
- Heart, Lung, Blood and Vascular Medicine Institute, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15216, USA
| | - Adam C Straub
- Heart, Lung, Blood and Vascular Medicine Institute, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15216, USA.
| |
Collapse
|
35
|
Straub AC, Zeigler AC, Isakson BE. The myoendothelial junction: connections that deliver the message. Physiology (Bethesda) 2015; 29:242-9. [PMID: 24985328 DOI: 10.1152/physiol.00042.2013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A vast amount of investigation has centered on how the endothelium and smooth muscle communicate. From this evidence, myoendothelial junctions have emerged as critical anatomical structures to regulate heterocellular cross talk. Indeed, there is now evidence that the myoendothelial junction serves as a signaling microdomain to organize proteins used to facilitate vascular heterocellular communication. This review highlights the evolving role of myoendothelial junctions in the context of vascular cell-cell communication.
Collapse
Affiliation(s)
- Adam C Straub
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Angela C Zeigler
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia; and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
| |
Collapse
|
36
|
Kang M, Lin N, Li C, Meng Q, Zheng Y, Yan X, Deng J, Ou Y, Zhang C, He J, Luo D. Cx43 phosphorylation on S279/282 and intercellular communication are regulated by IP3/IP3 receptor signaling. Cell Commun Signal 2014; 12:58. [PMID: 25262337 PMCID: PMC4195880 DOI: 10.1186/s12964-014-0058-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 09/11/2014] [Indexed: 11/17/2022] Open
Abstract
Background Inositol 1,4,5-trisphosphate receptor (IP3R) plays a pivotal role in the Ca2+ release process in a variety of cell types. Additionally, IP3R is distributed in ventricular intercalated discs, but its function(s) in this particular site remains unknown. Connexin (Cx43), the predominant gap junction (GJ) protein in ventricular myocardium, is linked to several signaling pathways that regulate Cx43 properties by (de)phosphorylation on multiple residues. Here, we investigated the regulatory role of IP3R in cell-cell communication and the mechanism(s) underlying this effect. Results In neonatal rat and adult mouse ventricular myocytes IP3R co-localized and co-immunoprecipitated with Cx43 in GJ plaques detected by immunostaining and western blot assays. Blocking IP3R with antagonists or silencing pan-IP3R expression with shRNA hindered the 6-carboxyfluorescein (6-CFDA) diffusion through GJs and desynchronized Ca2+ transients among confluent neonatal myocytes in culture, whereas stimulation of IP3R with IP3 ester or ATP exerted the opposite effect. Likewise, 6-CFDA propagation through GJs was modulated by IP3R activation or inhibition in cell pairs of isolated adult cardiomyocytes. Furthermore, IP3R activation or IP3R suppression promoted or suppressed, respectively, Cx43 phosphorylation on S279/282. Site-directed mutagenesis indicated that expression of a mutant Cx43-S282A (alanine) inhibited S279/282 phosphorylation and GJ permeability, while the S279A mutant showed the opposite effect in ventricular myocytes. Expression of these mutants in HEK293 cells revealed that cells with a dual S279/282 mutation failed to express exogenous Cx43, whereas cells with a single S279 or S282 mutation displayed Cx43 overexpression with increased phosphorylation of S279/282 and promotion of intercellular communication. Conclusions These results demonstrated, for the first time, that IP3R physically interacts with Cx43 and participates in the regulation of Cx43 phosphorylation on S279/282, thereby affecting GJ intercellular communication in ventricular myocytes. Electronic supplementary material The online version of this article (doi:10.1186/s12964-014-0058-6) contains supplementary material, which is available to authorized users.
Collapse
|
37
|
Maimon N, Titus PA, Sarelius IH. Pre-exposure to adenosine, acting via A(2A) receptors on endothelial cells, alters the protein kinase A dependence of adenosine-induced dilation in skeletal muscle resistance arterioles. J Physiol 2014; 592:2575-90. [PMID: 24687580 DOI: 10.1113/jphysiol.2013.265835] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Adenosine (ADO) is an endogenous vasodilatory purine widely recognized to be a significant contributor to functional hyperaemia. Despite this, many aspects of the mechanisms by which ADO induces dilation in small resistance arterioles are not established, or appear contradictory. These include: identification of the primary receptor subtype; its location on endothelial (EC) or vascular smooth muscle cells; whether ADO acts on KATP channels in these resistance vessels; and the contribution of cAMP/protein kinase A (PKA) signalling to the response. In intravital microscopy studies of intact or EC-denuded skeletal muscle arterioles, we show that ADO acts via A2A receptors located on ECs to produce vasodilation via activation of KATP channels located on vascular smooth muscle cells. Importantly, we found that the signalling pathway involves cAMP as expected, but that a requirement for PKA activation is demonstrable only if the vessel is not pre-exposed to ADO. That is, PKA-dependent signalling varies with pre-exposure to ADO. Further, we show that PKA activation alone is not sufficient to dilate these arterioles; an additional EC calcium-dependent signalling mechanism is required for vasodilation to ADO. The ability of arterioles in situ to respond to occupancy of a specific receptor by utilizing different cell signalling pathways under different conditions to produce the same response allows the arteriole to respond to key homeostatic requirements using more than a single signalling mechanism. Clearly, this is likely to be physiologically advantageous, but the role for this signalling flexibility in the integrated arteriolar response that underlies functional hyperaemia will require further exploration.
Collapse
Affiliation(s)
- Nir Maimon
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Patricia A Titus
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| | - Ingrid H Sarelius
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
| |
Collapse
|
38
|
Billaud M, Lohman AW, Johnstone SR, Biwer LA, Mutchler S, Isakson BE. Regulation of cellular communication by signaling microdomains in the blood vessel wall. Pharmacol Rev 2014; 66:513-69. [PMID: 24671377 DOI: 10.1124/pr.112.007351] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.
Collapse
Affiliation(s)
- Marie Billaud
- Dept. of Molecular Physiology and Biophysics, University of Virginia School of Medicine, PO Box 801394, Charlottesville, VA 22902.
| | | | | | | | | | | |
Collapse
|
39
|
Zeng Z, Zhang H, Lin N, Kang M, Zheng Y, Li C, Xu P, Wu Y, Luo D. Role of Inositol-1,4,5-Trisphosphate Receptor in the Regulation of Calcium Transients in Neonatal Rat Ventricular Myocytes. J Pharmacol Sci 2014. [DOI: 10.1254/jphs.14029fp] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
40
|
Westcott EB, Segal SS. Perivascular innervation: a multiplicity of roles in vasomotor control and myoendothelial signaling. Microcirculation 2013; 20:217-38. [PMID: 23289720 DOI: 10.1111/micc.12035] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/25/2012] [Indexed: 12/30/2022]
Abstract
The control of vascular resistance and tissue perfusion reflect coordinated changes in the diameter of feed arteries and the arteriolar networks they supply. Against a background of myogenic tone and metabolic demand, vasoactive signals originating from perivascular sympathetic and sensory nerves are integrated with endothelium-derived signals to produce vasodilation or vasoconstriction. PVNs release adrenergic, cholinergic, peptidergic, purinergic, and nitrergic neurotransmitters that lead to SMC contraction or relaxation via their actions on SMCs, ECs, or other PVNs. ECs release autacoids that can have opposing actions on SMCs. Respective cell layers are connected directly to each other through GJs at discrete sites via MEJs projecting through holes in the IEL. Whereas studies of intercellular communication in the vascular wall have centered on endothelium-derived signals that govern SMC relaxation, attention has increasingly focused on signaling from SMCs to ECs. Thus, via MEJs, neurotransmission from PVNs can evoke distinct responses from ECs subsequent to acting on SMCs. To integrate this emerging area of investigation in light of vasomotor control, the present review synthesizes current understanding of signaling events that originate within SMCs in response to perivascular neurotransmission in light of EC feedback. Although often ignored in studies of the resistance vasculature, PVNs are integral to blood flow control and can provide a physiological stimulus for myoendothelial communication. Greater understanding of these underlying signaling events and how they may be affected by aging and disease will provide new approaches for selective therapeutic interventions.
Collapse
Affiliation(s)
- Erika B Westcott
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
| | | |
Collapse
|
41
|
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.
Collapse
Affiliation(s)
- Sridevi Nagaraja
- Department of Biomedical Engineering, Florida International University, 10555 W. Flagler Street, EC 2674, Miami, FL 33174. USA
| | | | | | | | | |
Collapse
|
42
|
Wang JQ, Chen Q, Wang X, Wang QC, Wang Y, Cheng HP, Guo C, Sun Q, Chen Q, Tang TS. Dysregulation of mitochondrial calcium signaling and superoxide flashes cause mitochondrial genomic DNA damage in Huntington disease. J Biol Chem 2012; 288:3070-84. [PMID: 23250749 DOI: 10.1074/jbc.m112.407726] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Huntington disease (HD) is an inherited, fatal neurodegenerative disorder characterized by the progressive loss of striatal medium spiny neurons. Indications of oxidative stress are apparent in brain tissues from both HD patients and HD mouse models; however, the origin of this oxidant stress remains a mystery. Here, we used a yeast artificial chromosome transgenic mouse model of HD (YAC128) to investigate the potential connections between dysregulation of cytosolic Ca(2+) signaling and mitochondrial oxidative damage in HD cells. We found that YAC128 mouse embryonic fibroblasts exhibit a strikingly higher level of mitochondrial matrix Ca(2+) loading and elevated superoxide generation compared with WT cells, indicating that both mitochondrial Ca(2+) signaling and superoxide generation are dysregulated in HD cells. The excessive mitochondrial oxidant stress is critically dependent on mitochondrial Ca(2+) loading in HD cells, because blocking mitochondrial Ca(2+) uptake abolished elevated superoxide generation. Similar results were obtained using neurons from HD model mice and fibroblast cells from HD patients. More importantly, mitochondrial Ca(2+) loading in HD cells caused a 2-fold higher level of mitochondrial genomic DNA (mtDNA) damage due to the excessive oxidant generation. This study provides strong evidence to support a new causal link between dysregulated mitochondrial Ca(2+) signaling, elevated mitochondrial oxidant stress, and mtDNA damage in HD. Our results also indicate that reducing mitochondrial Ca(2+) uptake could be a therapeutic strategy for HD.
Collapse
Affiliation(s)
- Jiu-Qiang Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Nagaraja S, Kapela A, Tsoukias NM. Intercellular communication in the vascular wall: a modeling perspective. Microcirculation 2012; 19:391-402. [PMID: 22340204 DOI: 10.1111/j.1549-8719.2012.00171.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Movement of ions (Ca(2+) , K(+) , Na(+) , and Cl(-) ) and second messenger molecules like inositol 1, 4, 5-trisphosphate inside and in between different cells is the basis of many signaling mechanisms in the microcirculation. In spite of the vast experimental efforts directed toward evaluation of these fluxes, it has been a challenge to establish their roles in many essential microcirculatory phenomena. Recently, detailed theoretical models of calcium dynamics and plasma membrane electrophysiology have emerged to assist in the quantification of these intra and intercellular fluxes and enhance understanding of their physiological importance. This perspective reviews selected models relevant to estimation of such intra and intercellular ionic and second messenger fluxes and prediction of their relative significance to a variety of vascular phenomena, such as myoendothelial feedback, conducted responses, and vasomotion.
Collapse
Affiliation(s)
- Sridevi Nagaraja
- Department of Biomedical Engineering, Florida International University, Miami, Florida 33174, USA
| | | | | |
Collapse
|
44
|
Sandow SL, Senadheera S, Bertrand PP, Murphy TV, Tare M. Myoendothelial contacts, gap junctions, and microdomains: anatomical links to function? Microcirculation 2012; 19:403-15. [PMID: 22074364 DOI: 10.1111/j.1549-8719.2011.00146.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In several species and in many vascular beds, ultrastructural studies describe close contact sites between the endothelium and smooth muscle of <∼20nm. Such sites are thought to facilitate the local action of signaling molecules and/or the passage of current, as metabolic and electrical coupling conduits between the arterial endothelium and smooth muscle. These sites have the potential for bidirectional communication between the endothelium and smooth muscle, as a key pathway for coordinating vascular function. The aim of this brief review is to summarize the literature on the ultrastructural anatomy and distribution of key components of MECC sites in arteries. In addition to their traditional role of facilitating electrical coupling between the two cell layers, data on the role of MECC sites in arteries, as signaling microdomains involving a spatial localization of channels, receptors and calcium stores are highlighted. Diversity in the density and specific characteristics of MECC sites as signaling microdomains suggests considerable potential for functional diversity within and between arteries in health and disease.
Collapse
Affiliation(s)
- Shaun L Sandow
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
| | | | | | | | | |
Collapse
|
45
|
Billaud M, Lohman AW, Straub AC, Parpaite T, Johnstone SR, Isakson BE. Characterization of the thoracodorsal artery: morphology and reactivity. Microcirculation 2012; 19:360-72. [PMID: 22335567 DOI: 10.1111/j.1549-8719.2012.00172.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES In this paper, we describe the histological and contractile properties of the thoracodorsal artery (TDA), which indirectly feeds the spinotrapezius muscle. METHODS We used immunolabelling techniques to histologically characterize the TDA while the contractile properties were assessed using pressure arteriography. RESULTS Our results demonstrate that the TDA is composed of approximately one to two layers of smooth muscle cells, is highly innervated with adrenergic nerves, and develops spontaneous tone at intraluminal pressures above 80 mmHg. The reactivity of the TDA in response to various contractile agonists such as phenylephrine, noradrenaline, angiotensin II, serotonin, endothelin 1, and ATP, as well as vasodilators, shows that the TDA exhibits a remarkably comparable reactivity to what has been observed in mesenteric arteries. We further studied the different components of the TDA response to acetylcholine, and found that the TDA was sensitive to TRAM 34, a blocker of the intermediate conductance potassium channel, which is highly suggestive of an endothelium-dependent hyperpolarization. CONCLUSIONS We conclude that the TDA exhibits comparable characteristics to other current vascular models, with the additional advantage of being easily manipulated for molecular and ex vivo vasoreactivity studies.
Collapse
Affiliation(s)
- Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | | | | | | | | | | |
Collapse
|
46
|
Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
Collapse
Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
| | | | | |
Collapse
|
47
|
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]
|
48
|
Lohman AW, Billaud M, Isakson BE. Mechanisms of ATP release and signalling in the blood vessel wall. Cardiovasc Res 2012; 95:269-80. [PMID: 22678409 DOI: 10.1093/cvr/cvs187] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nucleotide adenosine 5'-triphosphate (ATP) has classically been considered the cell's primary energy currency. Importantly, a novel role for ATP as an extracellular autocrine and/or paracrine signalling molecule has evolved over the past century and extensive work has been conducted to characterize the ATP-sensitive purinergic receptors expressed on almost all cell types in the body. Extracellular ATP elicits potent effects on vascular cells to regulate blood vessel tone but can also be involved in vascular pathologies such as atherosclerosis. While the effects of purinergic signalling in the vasculature have been well documented, the mechanism(s) mediating the regulated release of ATP from cells in the blood vessel wall and circulation are now a key target of investigation. The aim of this review is to examine the current proposed mechanisms of ATP release from vascular cells, with a special emphasis on the transporters and channels involved in ATP release from vascular smooth muscle cells, endothelial cells, circulating red blood cells, and perivascular sympathetic nerves, including vesicular exocytosis, plasma membrane F(1)/F(0)-ATP synthase, ATP-binding cassette (ABC) transporters, connexin hemichannels, and pannexin channels.
Collapse
Affiliation(s)
- Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | | | | |
Collapse
|
49
|
The nanostructure of myoendothelial junctions contributes to signal rectification between endothelial and vascular smooth muscle cells. PLoS One 2012; 7:e33632. [PMID: 22523541 PMCID: PMC3327700 DOI: 10.1371/journal.pone.0033632] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 02/17/2012] [Indexed: 12/15/2022] Open
Abstract
Micro-anatomical structures in tissues have potential physiological effects. In arteries and arterioles smooth muscle cells and endothelial cells are separated by the internal elastic lamina, but the two cell layers often make contact through micro protrusions called myoendothelial junctions. Cross talk between the two cell layers is important in regulating blood pressure and flow. We have used a spatiotemporal mathematical model to investigate how the myoendothelial junctions affect the information flow between the two cell layers. The geometry of the model mimics the structure of the two cell types and the myoendothelial junction. The model is implemented as a 2D axi-symmetrical model and solved using the finite element method. We have simulated diffusion of Ca2+ and IP3 between the two cell types and we show that the micro-anatomical structure of the myoendothelial junction in itself may rectify a signal between the two cell layers. The rectification is caused by the asymmetrical structure of the myoendothelial junction. Because the head of the myoendothelial junction is separated from the cell it is attached to by a narrow neck region, a signal generated in the neighboring cell can easily drive a concentration change in the head of the myoendothelial protrusion. Subsequently the signal can be amplified in the head, and activate the entire cell. In contrast, a signal in the cell from which the myoendothelial junction originates will be attenuated and delayed in the neck region as it travels into the head of the myoendothelial junction and the neighboring cell.
Collapse
|
50
|
Kapela A, Nagaraja S, Parikh J, Tsoukias NM. Modeling Ca2+ signaling in the microcirculation: intercellular communication and vasoreactivity. Crit Rev Biomed Eng 2012; 39:435-60. [PMID: 22196162 DOI: 10.1615/critrevbiomedeng.v39.i5.50] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A network of intracellular signaling pathways and complex intercellular interactions regulate calcium mobilization in vascular cells, arteriolar tone, and blood flow. Different endothelium-derived vasoreactive factors have been identified and the importance of myoendothelial communication in vasoreactivity is now well appreciated. The ability of many vascular networks to conduct signals upstream also is established. This phenomenon is critical for both short-term changes in blood perfusion as well as long-term adaptations of a vascular network. In addition, in a phenomenon termed vasomotion, arterioles often exhibit spontaneous oscillations in diameter. This is thought to improve tissue oxygenation and enhance blood flow. Experimentation has begun to reveal important aspects of the regulatory machinery and the significance of these phenomena for the regulation of local perfusion and oxygenation. Mathematical modeling can assist in elucidating the complex signaling mechanisms that participate in these phenomena. This review highlights some of the important experimental studies and relevant mathematical models that provide the current understanding of these mechanisms in vasoreactivity.
Collapse
Affiliation(s)
- Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | | | | | | |
Collapse
|