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SenthilKumar G, Hammond ST, Zirgibel Z, Cohen KE, Beyer AM, Freed JK. Is the peripheral microcirculation a window into the human coronary microvasculature? J Mol Cell Cardiol 2024; 193:67-77. [PMID: 38848808 DOI: 10.1016/j.yjmcc.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/13/2024] [Accepted: 06/04/2024] [Indexed: 06/09/2024]
Abstract
An increasing body of evidence suggests a pivotal role for the microvasculature in the development of cardiovascular disease. A dysfunctional coronary microvascular network, specifically within endothelial cells-the inner most cell layer of vessels-is considered a strong, independent risk factor for future major adverse cardiac events. However, challenges exist with evaluating this critical vascular bed, as many of the currently available techniques are highly invasive and cost prohibitive. The more easily accessible peripheral microcirculation has surfaced as a potential surrogate in which to study mechanisms of coronary microvascular dysfunction and likewise may be used to predict poor cardiovascular outcomes. In this review, we critically evaluate a variety of prognostic, physiological, and mechanistic studies in humans to answer whether the peripheral microcirculation can add insight into coronary microvascular health. A conceptual framework is proposed that the health of the endothelium specifically may link the coronary and peripheral microvascular beds. This is supported by evidence showing a correlation between human coronary and peripheral endothelial function in vivo. Although not a replacement for investigating and understanding coronary microvascular function, the microvascular endothelium from the periphery responds similarly to (patho)physiological stress and may be leveraged to explore potential therapeutic pathways to mitigate stress-induced damage.
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Affiliation(s)
- Gopika SenthilKumar
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Stephen T Hammond
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States; Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Zachary Zirgibel
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Katie E Cohen
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States; Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Andreas M Beyer
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States; Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Julie K Freed
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States; Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.
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2
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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3
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Nemeth Z, Granger JP, Ryan MJ, Drummond HA. Is there a role of proinflammatory cytokines on degenerin-mediated cerebrovascular function in preeclampsia? Physiol Rep 2022; 10:e15376. [PMID: 35831968 PMCID: PMC9279847 DOI: 10.14814/phy2.15376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/25/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023] Open
Abstract
Preeclampsia (PE) is associated with adverse cerebrovascular effects during and following parturition including stroke, small vessel disease, and vascular dementia. A potential contributing factor to the cerebrovascular dysfunction is the loss of cerebral blood flow (CBF) autoregulation. Autoregulation is the maintenance of CBF to meet local demands with changes in perfusion pressure. When perfusion pressure rises, vasoconstriction of cerebral arteries and arterioles maintains flow and prevents the transfer of higher systemic pressure to downstream microvasculature. In the face of concurrent hypertension, loss of autoregulatory control exposes small delicate microvessels to injury from elevated systemic blood pressure. While placental ischemia is considered the initiating event in the preeclamptic cascade, the factor(s) mediating cerebrovascular dysfunction are poorly understood. Elevated plasma proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin-17 (IL-17), are potential mediators of autoregulatory loss. Impaired CBF responses to increases in systemic pressure are attributed to the impaired pressure-induced (myogenic) constriction of small cerebral arteries and arterioles in PE. Myogenic vasoconstriction is initiated by pressure-induced vascular smooth muscle cell (VSMC) stretch. Recent studies from our laboratory group indicate that proinflammatory cytokines impair the myogenic mechanism of CBF autoregulation via inhibition of vascular degenerin proteins, putative mediators of myogenic constriction in VSMCs. This brief review links studies showing the effect of proinflammatory cytokines on degenerin expression and CBF autoregulation to the pathological cerebral consequences of preeclampsia.
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Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMississippiUSA
- Institute of Translational MedicineFaculty of Medicine, Semmelweis UniversityBudapestHungary
- Department of Morphology and PhysiologyFaculty of Health Sciences, Semmelweis UniversityBudapestHungary
| | - Joey P. Granger
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Michael J. Ryan
- Department of Pharmacology, Physiology and NeuroscienceUniversity of South Carolina School of MedicineColumbiaSouth CarolinaUSA
| | - Heather A. Drummond
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMississippiUSA
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4
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Yang Q, Hori M. Characterization of Contractile Machinery of Vascular Smooth Muscles in Hypertension. Life (Basel) 2021; 11:life11070702. [PMID: 34357074 PMCID: PMC8304034 DOI: 10.3390/life11070702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022] Open
Abstract
Hypertension is a key risk factor for cardiovascular disease and it is a growing public health problem worldwide. The pathophysiological mechanisms of vascular smooth muscle (VSM) contraction contribute to the development of hypertension. Calcium (Ca2+)-dependent and -independent signaling mechanisms regulate the balance of the myosin light chain kinase and myosin light chain phosphatase to induce myosin phosphorylation, which activates VSM contraction to control blood pressure (BP). Here, we discuss the mechanism of the contractile machinery in VSM, especially RhoA/Rho kinase and PKC/CPI-17 of Ca2+ sensitization pathway in hypertension. The two signaling pathways affect BP in physiological and pathophysiological conditions and are highlighted in pulmonary, pregnancy, and salt-sensitive hypertension.
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Affiliation(s)
- Qunhui Yang
- Correspondence: ; Tel.: +81-3-5841-7940; Fax: +81-3-5841-8183
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Chennupati R, Wirth A, Favre J, Li R, Bonnavion R, Jin YJ, Wietelmann A, Schweda F, Wettschureck N, Henrion D, Offermanns S. Myogenic vasoconstriction requires G 12/G 13 and LARG to maintain local and systemic vascular resistance. eLife 2019; 8:49374. [PMID: 31549965 PMCID: PMC6777979 DOI: 10.7554/elife.49374] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022] Open
Abstract
Myogenic vasoconstriction is an autoregulatory function of small arteries. Recently, G-protein-coupled receptors have been involved in myogenic vasoconstriction, but the downstream signalling mechanisms and the in-vivo-function of this myogenic autoregulation are poorly understood. Here, we show that small arteries from mice with smooth muscle-specific loss of G12/G13 or the Rho guanine nucleotide exchange factor ARHGEF12 have lost myogenic vasoconstriction. This defect was accompanied by loss of RhoA activation, while vessels showed normal increases in intracellular [Ca2+]. In the absence of myogenic vasoconstriction, perfusion of peripheral organs was increased, systemic vascular resistance was reduced and cardiac output and left ventricular mass were increased. In addition, animals with defective myogenic vasoconstriction showed aggravated hypotension in response to endotoxin. We conclude that G12/G13- and Rho-mediated signaling plays a key role in myogenic vasoconstriction and that myogenic tone is required to maintain local and systemic vascular resistance under physiological and pathological condition.
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Affiliation(s)
- Ramesh Chennupati
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Angela Wirth
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - Julie Favre
- Laboratoire MITOVASC, UMR CNRS 6015 - INSERM 1083, Université d'Angers, Angers, France
| | - Rui Li
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Rémy Bonnavion
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Young-June Jin
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Astrid Wietelmann
- Scientific Service Group Nuclear Magnetic Resonance Imaging, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Centre for Molecular Medicine, Medical Faculty, JW Goethe University Frankfurt, Frankfurt, Germany.,German Center for Cardiovascular Research (DZHK), Berlin, Germany
| | - Daniel Henrion
- Laboratoire MITOVASC, UMR CNRS 6015 - INSERM 1083, Université d'Angers, Angers, France
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Centre for Molecular Medicine, Medical Faculty, JW Goethe University Frankfurt, Frankfurt, Germany.,German Center for Cardiovascular Research (DZHK), Berlin, Germany
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6
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El-Yazbi AF, Abd-Elrahman KS. ROK and Arteriolar Myogenic Tone Generation: Molecular Evidence in Health and Disease. Front Pharmacol 2017; 8:87. [PMID: 28280468 PMCID: PMC5322222 DOI: 10.3389/fphar.2017.00087] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/10/2017] [Indexed: 12/13/2022] Open
Abstract
The myogenic response is an inherent property of resistance arteries that warrants a relatively constant blood flow in response to changes in perfusion pressure and protect delicate organs from vascular insufficiencies and excessive blood flow. This fundamental phenomenon has been extensively studied aiming to elucidate the underlying mechanisms triggering smooth muscle contraction in response to intraluminal pressure elevation, particularly, Rho-associated kinase (ROK)-mediated Ca2+-independent mechanisms. The size of the resistance arteries limits the capacity to examine changes in protein phosphorylation/expression levels associated with ROK signaling. A highly sensitive biochemical detection approach was beneficial in examining the role of ROK in different force generation mechanisms along the course of myogenic constriction. In this mini review, we summarize recent results showing direct evidence for the contribution of ROK in development of myogenic response at the level of mechanotransduction, myosin light chain phosphatase inhibition and dynamic actin cytoskeleton reorganization. We will also present evidence that alterations in ROK signaling could underlie the progressive loss in myogenic response in a rat model of type 2 diabetes.
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Affiliation(s)
- Ahmed F El-Yazbi
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of BeirutBeirut, Lebanon; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria UniversityAlexandria, Egypt
| | - Khaled S Abd-Elrahman
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria UniversityAlexandria, Egypt; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of OttawaOttawa, ON, Canada
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7
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Szasz T, Webb RC. Rho-Mancing to Sensitize Calcium Signaling for Contraction in the Vasculature: Role of Rho Kinase. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:303-322. [PMID: 28212799 DOI: 10.1016/bs.apha.2016.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vascular smooth muscle contraction is an important physiological process contributing to cardiovascular homeostasis. The principal determinant of smooth muscle contraction is the intracellular free Ca2+ concentration, and phosphorylation of myosin light chain (MLC) by activated myosin light chain kinase (MLCK) in response to increased Ca2+ is the main pathway by which vasoconstrictor stimuli induce crossbridge cycling of myosin and actin filaments. A secondary pathway for vascular smooth muscle contraction that is not directly dependent on Ca2+ concentration, but rather mediating Ca2+ sensitization, is the RhoA/Rho kinase pathway. In response to contractile stimuli, the small GTPase RhoA activates its downstream effector Rho kinase which, in turn, promotes contraction via myosin light chain phosphatase (MLCP) inhibition. RhoA/Rho kinase-mediated MLCP inhibition occurs mainly by phosphorylation and inhibition of MYPT1, the regulatory subunit of MLCP, or by CPI-17-mediated inhibition of the catalytic subunit of MLCP. In this review, we describe the molecular mechanisms underlying the pivotal role exerted by Rho kinase on vascular smooth muscle contraction and discuss the main regulatory pathways for its activity.
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Affiliation(s)
- T Szasz
- Augusta University, Augusta, GA, United States.
| | - R C Webb
- Augusta University, Augusta, GA, United States
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Guan Z, Fellner RC, Van Beusecum J, Inscho EW. P2 receptors in renal autoregulation. Curr Vasc Pharmacol 2015; 12:818-28. [PMID: 24066935 DOI: 10.2174/15701611113116660152] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 03/06/2013] [Accepted: 05/01/2014] [Indexed: 11/22/2022]
Abstract
Autoregulation of renal blood flow and glomerular filtration rate is an essential function of the renal microcirculation. While the existence of this phenomenon has been known for many years, the exact mechanisms that underlie this regulatory system remain poorly understood. The work of many investigators has provided insights into many aspects of the autoregulatory mechanism, but many critical components remain elusive. This review is intended to update the reader on the role of P2 purinoceptors as a postulated mechanism responsible for renal autoregulatory resistance adjustments. It will summarize recent advances in normal function and it will touch on more recent ideas regarding autoregulatory insufficiency in hypertension and inflammation. Current thoughts on the nature of the mechanosensor responsible for myogenic behavior will be also be discussed as well as current thoughts on the mechanisms involved in ATP release to the extracellular fluid space.
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Affiliation(s)
| | | | | | - Edward W Inscho
- Department of Physiology, Medical College of Georgia, Georgia Regents University, 1120 15th Street, Augusta, Georgia 30912-3000.
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9
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Castorena-Gonzalez JA, Staiculescu MC, Foote C, Martinez-Lemus LA. Mechanisms of the inward remodeling process in resistance vessels: is the actin cytoskeleton involved? Microcirculation 2015; 21:219-29. [PMID: 24635509 DOI: 10.1111/micc.12105] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/04/2013] [Indexed: 12/22/2022]
Abstract
The resistance arteries and arterioles are the vascular components of the circulatory system where the greatest drop in blood pressure takes place. Consequently, these vessels play a preponderant role in the regulation of blood flow and the modulation of blood pressure. For this reason, the inward remodeling process of the resistance vasculature, as it occurs in hypertension, has profound consequences on the incidence of life-threatening cardiovascular events. In this manuscript, we review some of the most prominent characteristics of inwardly remodeled resistance arteries including their changes in vascular passive diameter, wall thickness, and elastic properties. Then, we explore the known contribution of the different components of the vascular wall to the characteristics of inwardly remodeled vessels, and pay particular attention to the role the vascular smooth muscle actin cytoskeleton may play on the initial stages of the remodeling process. We end by proposing potential ways by which many of the factors and mechanisms known to participate in the inward remodeling process may be associated with cytoskeletal modifications and participate in reducing the passive diameter of resistance vessels.
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Affiliation(s)
- Jorge A Castorena-Gonzalez
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA; Department of Biological Engineering, University of Missouri, Columbia, Missouri, USA
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10
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Souza-Smith FM, Molina PE, Breslin JW. Reduced RhoA activity mediates acute alcohol intoxication-induced inhibition of lymphatic myogenic constriction despite increased cytosolic [Ca(2+) ]. Microcirculation 2014; 20:377-84. [PMID: 23237297 DOI: 10.1111/micc.12032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 12/10/2012] [Indexed: 12/01/2022]
Abstract
OBJECTIVES We previously showed that AAI reduces lymphatic myogenic constriction in response to step increases in luminal pressure. Because of the known role of Ca(2+) in smooth muscle contractile responses, we investigated how alcohol impacts cyclic Ca(2+) and whether changes in RhoA/ROCK-mediated Ca(2+) sensitivity underlie the alcohol-induced reduction of myogenic responsiveness. METHODS AAI was produced by intragastric administration of 30% alcohol in rats. Mesenteric lymphatics were cannulated and loaded with Fura-2 AM to [Ca(2+) ]i for 30 minutes after AAI. Active GTP-bound RhoA levels were determined by ELISA. To determine ROCK's ability to restore myogenic responsiveness following AAI, isolated lymphatics were transfected with constitutively active ca-ROCK protein. RESULTS Lymphatics from alcohol-treated rats displayed significantly larger Ca(2+) transients. Also, step increases in luminal pressure caused a gradual rise in the basal [Ca(2+) ]i between transients that was greater in lymphatics submitted to AAI, compared to vehicle control. RhoA-GTP was significantly reduced in lymphatics from the AAI group, compared to vehicle control. Transfection with ca-ROCK protein restored the myogenic response of lymphatic vessels isolated from AAI animals. CONCLUSIONS The data strongly suggest that the alcohol-induced inhibition of mesenteric lymphatic myogenic constriction is mediated by reduced RhoA/ROCK-mediated Ca(2+) sensitivity.
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Affiliation(s)
- Flavia M Souza-Smith
- Department of Physiology, Alcohol and Drug Abuse Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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Wang J, Liu X, Zhong Y. Rho/Rho-associated kinase pathway in glaucoma (Review). Int J Oncol 2013; 43:1357-67. [PMID: 24042317 DOI: 10.3892/ijo.2013.2100] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 08/21/2013] [Indexed: 11/06/2022] Open
Abstract
The Rho/ROCK pathway plays important roles in the modulation of the cytoskeletal integrity of cells, the synthesis of extracellular matrix components in the aqueous humor outflow tissue and the permeability of Schlemm's canal endothelial cells. The activation of the Rho/ROCK pathway results in trabecular meshwork (TM) contraction, and the inhibition of this pathway would provoke relaxation of TM with subsequent increase in outflow facility and, thereby, decrease intraocular pressure (IOP). ROCK inhibitors also serve as potent anti‑scarring agents via inhibition of transdifferentiation of tenon fibroblasts into myofibroblasts. Furthermore, the RhoA/ROCK pathway is involved in optic nerve neuroprotection. Inactivation of Rho/ROCK signaling increase ocular blood flow, improve retinal ganglion cell (RGC) survival and promote RGC axon regeneration. Considering the IOP modulation, potent bleb anti-scarring effect and neuroprotective properties of ROCK inhibitors, the Rho/ROCK pathway is an attractive target for anti-glaucoma therapy, and it may be used for human therapy in the near future.
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Affiliation(s)
- Jing Wang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai 200025, P.R. China
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12
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Role of RhoA in Regulating the Pump Function of Isolated Lymphatics From Hemorrhagic Shock Rats. Shock 2013; 40:49-58. [DOI: 10.1097/shk.0b013e31829635cf] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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13
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Retailleau K, Toutain B, Galmiche G, Fassot C, Sharif-Naeini R, Kauffenstein G, Mericskay M, Duprat F, Grimaud L, Merot J, Lardeux A, Pizard A, Baudrie V, Jeunemaitre X, Feil R, Göthert JR, Lacolley P, Henrion D, Li Z, Loufrani L. Selective Involvement of Serum Response Factor in Pressure-Induced Myogenic Tone in Resistance Arteries. Arterioscler Thromb Vasc Biol 2013; 33:339-46. [DOI: 10.1161/atvbaha.112.300708] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
In resistance arteries, diameter adjustment in response to pressure changes depends on the vascular cytoskeleton integrity. Serum response factor (SRF) is a dispensable transcription factor for cellular growth, but its role remains unknown in resistance arteries. We hypothesized that SRF is required for appropriate microvascular contraction.
Methods and Results—
We used mice in which SRF was specifically deleted in smooth muscle or endothelial cells, and their control. Myogenic tone and pharmacological contraction was determined in resistance arteries. mRNA and protein expression were assessed by quantitative real-time PCR (qRT-PCR) and Western blot. Actin polymerization was determined by confocal microscopy. Stress-activated channel activity was measured by patch clamp. Myogenic tone developing in response to pressure was dramatically decreased by SRF deletion (5.9±2.3%) compared with control (16.3±3.2%). This defect was accompanied by decreases in actin polymerization, filamin A, myosin light chain kinase and myosin light chain expression level, and stress-activated channel activity and sensitivity in response to pressure. Contractions induced by phenylephrine or U46619 were not modified, despite a higher sensitivity to p38 blockade; this highlights a compensatory pathway, allowing normal receptor-dependent contraction.
Conclusion—
This study shows for the first time that SRF has a major part to play in the control of local blood flow via its central role in pressure-induced myogenic tone in resistance arteries.
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Affiliation(s)
- Kevin Retailleau
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Bertrand Toutain
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Guillaume Galmiche
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Céline Fassot
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Reza Sharif-Naeini
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Gilles Kauffenstein
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Mathias Mericskay
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Fabrice Duprat
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Linda Grimaud
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Jean Merot
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Aurelie Lardeux
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Anne Pizard
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Véronique Baudrie
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Xavier Jeunemaitre
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Robert Feil
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Joachim R. Göthert
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Patrick Lacolley
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Daniel Henrion
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Zhenlin Li
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
| | - Laurent Loufrani
- From the CNRS UMR-6214, INSERM U1083, Université d’Angers, PRES LUNAM, Angers, France (K.R., B.T., C.F., G.K., L.G., D.H., L.L.); CHU Angers, France (D.H., L.L.); Université Pierre & Marie Curie, Paris, France (G.G., M.M., Z.L.); IPMC-CNRS, Valbonne, France (R.S.-N., F.D.); INSERM 915, Nantes, France (J.M., A.L.); INSERM 961, Vandoeuvre les Nancy, France (A.P., P.L.); INSERM 970, Paris–Centre de Recherche Cardiovasculaire (PARCC), Faculty of Medicine, Université Paris Descartes, PRES Sorbonne
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Moreno-Domínguez A, Colinas O, El-Yazbi A, Walsh EJ, Hill MA, Walsh MP, Cole WC. Ca2+ sensitization due to myosin light chain phosphatase inhibition and cytoskeletal reorganization in the myogenic response of skeletal muscle resistance arteries. J Physiol 2012; 591:1235-50. [PMID: 23230233 DOI: 10.1113/jphysiol.2012.243576] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract The myogenic response of resistance arteries to intravascular pressure elevation is a fundamental physiological mechanism of crucial importance for blood pressure regulation and organ-specific control of blood flow. The importance of Ca(2+) entry via voltage-gated Ca(2+) channels leading to phosphorylation of the 20 kDa myosin regulatory light chains (LC20) in the myogenic response is well established. Recent studies, however, have suggested a role for Ca(2+) sensitization via activation of the RhoA/Rho-associated kinase (ROK) pathway in the myogenic response. The possibility that enhanced actin polymerization is also involved in myogenic vasoconstriction has been suggested. Here, we have used pressurized resistance arteries from rat gracilis and cremaster skeletal muscles to assess the contribution to myogenic constriction of Ca(2+) sensitization due to: (1) phosphorylation of the myosin targeting subunit of myosin light chain phosphatase (MYPT1) by ROK; (2) phosphorylation of the 17 kDa protein kinase C (PKC)-potentiated protein phosphatase 1 inhibitor protein (CPI-17) by PKC; and (3) dynamic reorganization of the actin cytoskeleton evoked by ROK and PKC. Arterial diameter, MYPT1, CPI-17 and LC20 phosphorylation, and G-actin content were determined at varied intraluminal pressures ± H1152, GF109203X or latrunculin B to suppress ROK, PKC and actin polymerization, respectively. The myogenic response was associated with an increase in MYPT1 and LC20 phosphorylation that was blocked by H1152. No change in phospho-CPI-17 content was detected although the PKC inhibitor, GF109203X, suppressed myogenic constriction. Basal LC20 phosphorylation at 10 mmHg was high at ∼40%, increased to a maximal level of ∼55% at 80 mmHg, and exhibited no additional change on further pressurization to 120 and 140 mmHg. Myogenic constriction at 80 mmHg was associated with a decline in G-actin content by ∼65% that was blocked by inhibition of ROK or PKC. Taken together, our findings indicate that two mechanisms of Ca(2+) sensitization (ROK-mediated phosphorylation of MYPT1-T855 with augmentation of LC20 phosphorylation, and a ROK- and PKC-evoked increase in actin polymerization) contribute to force generation in the myogenic response of skeletal muscle arterioles.
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Affiliation(s)
- Alejandro Moreno-Domínguez
- The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Libin Cardiovascular Institute and Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., Calgary, Alberta, Canada T2N 4N1
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15
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Lidington D, Schubert R, Bolz SS. Capitalizing on diversity: an integrative approach towards the multiplicity of cellular mechanisms underlying myogenic responsiveness. Cardiovasc Res 2012. [PMID: 23180720 DOI: 10.1093/cvr/cvs345] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The intrinsic ability of resistance arteries to respond to transmural pressure is the single most important determinant of their function. Despite an ever-growing catalogue of signalling pathways that underlie the myogenic response, it remains an enigmatic mechanism. The myogenic response's mechanistic diversity has largely been attributed to 'hard-wired' differences across species and vascular beds; however, emerging evidence suggests that the mechanistic basis for the myogenic mechanism is, in fact, 'plastic'. This means that the myogenic response can change quantitatively (i.e. change in magnitude) and qualitatively (i.e. change in mechanistic basis) in response to environmental challenges (e.g. disease conditions). Consequently, understanding the dynamics of how the myogenic response capitalizes on its mechanistic diversity is key to unlocking clinically viable interventions. Using myogenic sphingosine-1-phosphate (S1P) signalling as an example, this review illustrates the remarkable plasticity of the myogenic response. We propose that currently unidentified 'organizational programmes' dictate the contribution of individual signalling pathways to the myogenic response and introduce the concept that certain signalling elements act as 'divergence points' (i.e. as the potential higher level regulatory sites). In the context of pressure-induced S1P signalling, the S1P-generating enzyme sphingosine kinase 1 serves as a divergence point, by orchestrating the calcium-dependent and -independent signalling pathways underlying microvascular myogenic responsiveness. By acting on divergence points, the proposed 'organizational programmes' could form the basis for the flexible recruitment and fine-tuning of separate signalling streams that underlie adaptive changes to the myogenic response and its distinctiveness across species and vascular beds.
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Affiliation(s)
- Darcy Lidington
- Department of Physiology, University of Toronto, Medical Science Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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16
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Martinsen A, Yerna X, Rath G, Gomez EL, Dessy C, Morel N. Different effect of Rho kinase inhibition on calcium signaling in rat isolated large and small arteries. J Vasc Res 2012; 49:522-33. [PMID: 22948674 DOI: 10.1159/000341230] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 06/10/2012] [Indexed: 11/19/2022] Open
Abstract
In addition to its role in the regulation of artery contraction, Rho kinase (ROCK) was reported to be involved in the cytosolic calcium response to vasoconstrictor agonists in rat aorta and superior mesenteric artery (SMA). However, it remains to be determined whether ROCK also contributes to calcium signaling in resistance arteries, which play a major role in blood pressure regulation. The investigation of the effect of ROCK inhibition on the calcium and contractile responses of rat resistance mesenteric artery (RMA), in comparison with aorta and SMA, indicated that the calcium response to noradrenaline was inhibited by the ROCK inhibitor Y-27632 in aorta and SMA but not in RMA. The effect of Y-27632 on the calcium signal was unaffected by cytochalasin-D. ROCK activation in noradrenaline-stimulated arteries was confirmed by the inhibition of myosin light chain phosphorylation by Y-27632. Moreover, noradrenaline-induced calcium signaling was similarly inhibited by nimodipine in aorta, SMA and RMA, but nimodipine sensitivity of the contraction increased from the aorta to the RMA, suggesting that the contraction was controlled by different sources of calcium. In pressurized RMA, Y-27632 and H-1152 depressed pressure-induced calcium responses and abolished myogenic contraction. These results stress the important differences in calcium signaling between conductance and resistance arteries.
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Affiliation(s)
- Anneloes Martinsen
- Department of Cellular Physiology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
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17
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Kauffenstein G, Laher I, Matrougui K, Guérineau NC, Henrion D. Emerging role of G protein-coupled receptors in microvascular myogenic tone. Cardiovasc Res 2012; 95:223-32. [PMID: 22637750 DOI: 10.1093/cvr/cvs152] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Blood flow autoregulation results from the ability of resistance arteries to reduce or increase their diameters in response to changes in intravascular pressure. The mechanism by which arteries maintain a constant blood flow to organs over a range of pressures relies on this myogenic response, which defines the intrinsic property of the smooth muscle to contract in response to stretch. The resistance to flow created by myogenic tone (MT) prevents tissue damage and allows the maintenance of a constant perfusion, despite fluctuations in arterial pressure. Interventions targeting MT may provide a more rational therapeutic approach in vascular disorders, such as hypertension, vasospasm, chronic heart failure, or diabetes. Despite its early description by Bayliss in 1902, the cellular and molecular mechanisms underlying MT remain poorly understood. We now appreciate that MT requires a complex mechanotransduction converting a physical stimulus (pressure) into a biological response (change in vessel diameter). Although smooth muscle cell depolarization and a rise in intracellular calcium concentration are recognized as cornerstones of the myogenic response, the role of wall strain-induced formation of vasoactive mediators is less well established. The vascular system expresses a large variety of Class 1 G protein-coupled receptors (GPCR) activated by an eclectic range of chemical entities, including peptides, lipids, nucleotides, and amines. These messengers can function in blood vessels as vasoconstrictors. This review focuses on locally generated GPCR agonists and their proposed contributions to MT. Their interplay with pivotal G(q-11) and G(12-13) protein signalling is also discussed.
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Affiliation(s)
- Gilles Kauffenstein
- Biologie Neurovasculaire et Mitochondriale Intégrée, UMR CNRS 6214 INSERM 1083, Université d'Angers, France
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18
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Kita S, Iwamoto T. [Functional interaction between Na(+)/Ca(2+) exchanger and sodium-transporting proteins in plasma membrane microdomains]. Nihon Yakurigaku Zasshi 2012; 139:61-5. [PMID: 22322929 DOI: 10.1254/fpj.139.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Effects of Rho-associated protein kinase inhibitors Y-27632 and Y-39983 on isolated rabbit ciliary arteries. Jpn J Ophthalmol 2011; 55:411-417. [PMID: 21667088 DOI: 10.1007/s10384-011-0048-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 02/22/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE In normotensive eyes, reduced ocular blood flow can lead to glaucoma pathogenesis. Drugs that reduce intraocular pressure (IOP) often cause vasodilation of the ciliary arteries and improve blood flow to the eye. A novel class of drugs called Rho-associated coiled coil-forming protein kinase (ROCK) inhibitors can lower IOP. Therefore, we tested the ability of two ROCK inhibitors, Y-27632 and Y39983, to relax rabbit ciliary arteries. METHODS We measured in vitro ciliary artery smooth muscle contractions by isometric tension recordings and changes of intracellular free calcium concentration ([Ca(2+)](i)) by fluorescence photometry. RESULTS Both Y-27632 and Y-39983 induced a concentration-dependent relaxation in rabbit ciliary arteries precontracted with a high-potassium (high-K) solution. The amplitude of relaxation induced by Y-27632 and Y-39983 was not affected by either 100 μM N (G)-nitro-L: -arginine methyl ester (L: -NAME) or 10 μM indomethacin. In Ca(2+)-free solution, Y-27632 and Y-39983 significantly inhibited the transient contraction of ciliary arteries induced by 10 μM histamine. However, neither Y-27632 nor Y-39983 affected the elevation of [Ca(2+)](i) induced by high-K solution and histamine. CONCLUSIONS We concluded that Y-27632 and Y-39983 relaxed isolated rabbit ciliary artery segments in vitro. The mechanism of relaxation was not dependent on endothelial-derived factors such as nitric oxide (NO) or prostacyclin, nor was it dependent on changes in intracellular Ca(2+) concentration.
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20
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Role of myosin light chain kinase and myosin light chain phosphatase in the resistance arterial myogenic response to intravascular pressure. Arch Biochem Biophys 2011; 510:160-73. [DOI: 10.1016/j.abb.2011.02.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 12/19/2022]
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21
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Enouri S, Monteith G, Johnson R. Characteristics of myogenic reactivity in isolated rat mesenteric veins. Am J Physiol Regul Integr Comp Physiol 2011; 300:R470-8. [DOI: 10.1152/ajpregu.00491.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanisms of mechanically induced venous tone and its interaction with the endothelium and key vasoactive neurohormones are not well established. We investigated the contribution of the endothelium, l-type voltage-operated calcium channels (l-VOCCs), and PKC and Rho kinase to myogenic reactivity in mesenteric vessels exposed to increasing transmural pressure. The interaction of myogenic reactivity with norepinephrine (NE) and endothelin-1 (ET-1) was also investigated. Pressure myography was used to study isolated, cannulated, third-order rat mesenteric small veins and arteries. NE and ET-1 concentration response curves were constructed at low, intermediate, and high transmural pressures. Myogenic reactivity was not altered by nitric oxide synthase inhibition with Nω-nitro-l-arginine (l-NNA; 100 μM) or endothelium removal in both vessels. l-VOCCs blockade (nifedipine, 1 μM) completely abolished arterial tone, while only partially reducing venous tone. PKC (chelerythrine, 2.5 μM) and Rho kinase (Y27632, 3 μM) inhibitors largely abolished venous and arterial myogenic reactivity. There was no significant difference in the sensitivity of NE or ET-1-induced contractions within vessels. However, veins were more sensitive to NE and ET-1 when compared with corresponding arteries at low, intermediate, and high transmural pressures, respectively. These results suggest that 1) myogenic factors are important contributors to net venous tone in mesenteric veins; 2) PKC and Rho activation are important in myogenic reactivity in both vessels, while l-VOCCs play a limited role in the veins vs. the arteries, and the endothelium does not appear to modulate myogenic reactivity in either vessel type; and 3) mesenteric veins maintain an enhanced sensitivity to NE and ET-1 compared with the arteries when studied under conditions of changing transmural distending pressure.
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Affiliation(s)
| | - Gabrielle Monteith
- Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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22
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23
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Kita S, Iwamoto T. [Mechanisms for linking high salt intake to vascular tone: role of Na(+) pump and Na(+)/Ca²(+) exchanger coupling]. YAKUGAKU ZASSHI 2010; 130:1399-405. [PMID: 21048395 DOI: 10.1248/yakushi.130.1399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Excessive salt intake is a major risk factor for hypertension. However, the underlying molecular relationship between salt and hypertension is not fully understood. Recently discovered cardiotonic steroids, such as endogenous ouabain and other steroids, have been proposed as candidate intermediaries. Plasma cardiotonic steroids are significantly elevated in patients with essential hypertension and in salt-dependent hypertensive animals. Generally, it is believed that cardiotonic steroids inhibit Na(+) pump activity and lead to an increase in the cytosolic Na(+) concentration. Cellular Na(+) accumulation raises the cytosolic Ca²(+) concentration through the involvement of Na(+)/Ca²(+) exchanger type 1 (NCX1). In isolated arteries from α2 Na(+) pump knockout mice (α2(+/-)), myogenic tone is increased, and NCX inhibitor normalizes the elevated myogenic tone in α2(+/-) arteries. The NCX inhibitor lowers arterial blood pressure in salt-dependent hypertensive rats but not in other types of hypertensive rats or in normotensive rats. Furthermore, smooth muscle-specific NCX1 transgenic mice are hypersensitive to salt, whereas mice with smooth muscle-specific knockout of NCX1 (NCX1(SM-/-)) have low salt sensitivity. These results suggest that functional coupling between the vascular α2 Na(+) pump and NCX1 is a critical molecular mechanism for salt-induced blood pressure elevation.
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Affiliation(s)
- Satomi Kita
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Japan.
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Charles SM, Zhang L, Cipolla MJ, Buchholz JN, Pearce WJ. Roles of cytosolic Ca2+ concentration and myofilament Ca2+ sensitization in age-dependent cerebrovascular myogenic tone. Am J Physiol Heart Circ Physiol 2010; 299:H1034-44. [PMID: 20639216 DOI: 10.1152/ajpheart.00214.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In light of evidence that immature arteries contain a higher proportion of noncontractile smooth muscle cells than found in fully differentiated mature arteries, the present study explored the hypothesis that age-related differences in the smooth muscle phenotype contribute to age-related differences in contractility. Because Ca(2+) handling differs markedly between contractile and noncontractile smooth muscle, the present study specifically tested the hypothesis that the relative contributions of Ca(2+) influx and myofilament sensitization to myogenic tone are upregulated, whereas Ca(2+) release is downregulated, in immature [14 days postnatal (P14)] compared with mature (6 mo old) rat middle cerebral arteries (MCAs). Myofilament Ca(2+) sensitivity measured in β-escin-permeabilized arteries increased with pressure in P14 but not adult MCAs. Cyclopiazonic acid (an inhibitor of Ca(2+) release from the sarcoplasmic reticulum) increased diameter and reduced Ca(2+) in adult MCAs but increased diameter with no apparent change in Ca(2+) in P14 MCAs. La(3+) (Ca(2+) influx inhibitor) increased diameter and decreased Ca(2+) in adult MCAs, but in P14 MCAs, La(3+) increased diameter with no apparent change in Ca(2+). After treatment with both La(3+) and CPA, diameters were passive in both adult and P14 MCAs, but Ca(2+) was decreased only in adult MCAs. To quantify the fraction of smooth muscle cells in the fully differentiated contractile phenotype, extents of colocalization between smooth muscle α-actin and SM2 myosin heavy chain were determined and found to be at least twofold greater in adult than pup MCAs. These data suggest that compared with adult MCAs, pup MCAs contain a greater proportion of noncontractile smooth muscle and, as a consequence, rely more on myofilament Ca(2+) sensitization and Ca(2+) influx to maintain myogenic reactivity. The inability of La(3+) to reduce cytosolic Ca(2+) in the pup MCA appears due to La(3+)-insensitive noncontractile smooth muscle cells, which contribute to the spatially averaged measurements of Ca(2+) but not contraction.
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Affiliation(s)
- Shelton M Charles
- Center for Perinatal Biology, Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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Inscho EW. ATP, P2 receptors and the renal microcirculation. Purinergic Signal 2009; 5:447-60. [PMID: 19294530 PMCID: PMC2776135 DOI: 10.1007/s11302-009-9147-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 05/16/2008] [Indexed: 01/22/2023] Open
Abstract
Purinoceptors are rapidly becoming recognised as important regulators of tissue and organ function. Renal expression of P2 receptors is broad and diverse, as reflected by the fact that P2 receptors have been identified in virtually every major tubular/vascular element. While P2 receptor expression by these renal structures is recognised, the physiological functions that they serve remains to be clarified. Renal vascular P2 receptor expression is complex and poorly understood. Evidence suggests that different complements of P2 receptors are expressed by individual renal vascular segments. This unique distribution has given rise to the postulate that P2 receptors are important for renal vascular function, including regulation of preglomerular resistance and autoregulatory behaviour. More recent studies have also uncovered evidence that hypertension reduces renal vascular reactivity to P2 receptor stimulation in concert with compromised autoregulatory capability. This review will consolidate findings related to the role of P2 receptors in regulating renal microvascular function and will present areas of controversy related to the respective roles of ATP and adenosine in autoregulatory resistance adjustments.
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Affiliation(s)
- Edward W Inscho
- Department of Physiology, Medical College of Georgia, Augusta, Georgia,
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Büssemaker E, Herbrig K, Pistrosch F, Palm C, Passauer J. Role of rho-kinase in the regulation of vascular tone in hypertensive renal transplant recipients. Atherosclerosis 2009; 207:567-72. [PMID: 19717154 DOI: 10.1016/j.atherosclerosis.2009.05.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 05/18/2009] [Accepted: 05/19/2009] [Indexed: 11/18/2022]
Abstract
Activation of rho-kinase (ROK) is involved in the development of hypertension as it is a potent regulator of vascular smooth muscle cell (VSMC) contractility. Here we evaluated whether activation of ROK is present in hypertensive kidney transplant recipients (NTX). We tested the effect of the ROK-inhibitor fasudil on the regulation of forearm blood flow (FBF) in NTX and in healthy control subjects (CTL). In addition potential modulating effects of ROK-inhibition on local vascular nitric oxide (NO) release were studied. The effect of intra-arterial infusion of fasudil on FBF was studied by venous-occlusion plethysmography in NTX and CTL. To unmask the role of NO fasudil was infused with/without clamping of vascular NO in NTX and CTL. To unravel the basal NO-mediated tone the NO-synthase inhibitor l-NMMA was infused. Fasudil markedly but comparably increased FBF in NTX and CTL. The vascular response to fasudil was blunted during NO-clamp in CTL (104+/-18% vs. 244+/-48% for NO-clamp+fasudil vs. fasudil alone; baseline=0%, P<0.05) but not in NTX. The l-NMMA-induced vasoconstriction was impaired in NTX compared to CTL. In NTX and CTL basal vascular tone equally depends on ROK. Fasudil-induced vasodilatation is partly mediated by vascular NO in CTL but not in NTX. The greater NO-insensitive fasudil-induced increase in FBF in NTX suggests an increased ROK-mediated VSMC constrictor tone in these patients. Basal NO-mediated tone is attenuated in hypertensive NTX.
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Affiliation(s)
- E Büssemaker
- Medizinische Klinik und Poliklinik D, Universitätsklinikum Münster, Münster, Germany.
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Johnson RP, El-Yazbi AF, Takeya K, Walsh EJ, Walsh MP, Cole WC. Ca2+ sensitization via phosphorylation of myosin phosphatase targeting subunit at threonine-855 by Rho kinase contributes to the arterial myogenic response. J Physiol 2009; 587:2537-53. [PMID: 19359365 DOI: 10.1113/jphysiol.2008.168252] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ca(2+) sensitization has been postulated to contribute to the myogenic contraction of resistance arteries evoked by elevation of transmural pressure. However, the biochemical evidence of pressure-induced increases in phosphorylated myosin light chain phosphatase (MLCP) targeting subunit 1 (MYPT1) and/or 17 kDa protein kinase C (PKC)-potentiated protein phosphatase 1 inhibitor protein (CPI-17) required to sustain this view is not currently available. Here, we determined whether Ca(2+) sensitization pathways involving Rho kinase (ROK)- and PKC-dependent phosphorylation of MYPT1 and CPI-17, respectively, contribute to the myogenic response of rat middle cerebral arteries. ROK inhibitors (Y27632, 0.03-10 micromol l(-1); H1152, 0.001-0.3 micromol l(-1)) and PKC inhibitors (GF109203X, 3 micromol l(-1); Gö6976; 10 micromol l(-1)) suppressed myogenic vasoconstriction between 40 and 120 mmHg. An improved, highly sensitive 3-step Western blot method was developed for detection and quantification of MYPT1 and CPI-17 phosphorylation. Increasing pressure from 10 to 60 or 100 mmHg significantly increased phosphorylation of MYPT1 at threonine-855 (T855) and myosin light chain (LC(20)). Phosphorylation of MYPT1 at threonine-697 (T697) and CPI-17 were not affected by pressure. Pressure-evoked elevations in MYPT1-T855 and LC(20) phosphorylation were reduced by H1152, but MYPT1-T697 phosphorylation was unaffected. Inhibition of PKC with GF109203X did not affect MYPT1 or LC(20) phosphorylation at 100 mmHg. Our findings provide the first direct, biochemical evidence that a Ca(2+) sensitization pathway involving ROK-dependent phosphorylation of MYPT1 at T855 (but not T697) and subsequent augmentation of LC(20) phosphorylation contributes to myogenic control of arterial diameter in the cerebral vasculature. In contrast, suppression of the myogenic response by PKC inhibitors cannot be attributed to block of Ca(2+) sensitization mediated by CPI-17 or MYPT1 phosphorylation.
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Affiliation(s)
- Rosalyn P Johnson
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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Inscho EW, Cook AK, Webb RC, Jin LM. Rho-kinase inhibition reduces pressure-mediated autoregulatory adjustments in afferent arteriolar diameter. Am J Physiol Renal Physiol 2009; 296:F590-7. [PMID: 19129253 DOI: 10.1152/ajprenal.90703.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Preglomerular resistance is regulated by calcium influx- and mobilization-dependent mechanisms; however, the role of Rho-kinase in calcium sensitization in the intact kidney has not been carefully examined. Experiments were performed to test the hypothesis that Rho-kinase inhibition blunts pressure-mediated afferent arteriolar autoregulatory behavior and vasoconstrictor responses evoked by angiotensin II and P2X1 receptor activation. Rat kidneys were studied in vitro using the blood-perfused juxtamedullary nephron technique. Autoregulatory behavior was assessed before and during Rho-kinase inhibition with Y-27632 (1.0 microM; n = 5). Control diameter averaged 14.3 +/- 0.8 microm and increased to 18.1 +/- 0.9 microm (P < 0.05) during Y-27632 treatment. In the continued presence of Y-27632, reducing perfusion pressure to 65 mmHg slightly increased diameter to 18.7 +/- 1.0 microm. Subsequent pressure increases to 130 and 160 mmHg yielded afferent arteriolar diameters of 17.5 +/- 0.8 and 16.6 +/- 0.6 microm (P < 0.05). This 11% decline in diameter is significantly smaller than the 40% decrease obtained in untreated kidneys. The inhibitory effects of Y-27632 on autoregulatory behavior were concentration dependent. Angiotensin II responses were blunted by Y-27632. Angiotensin II (1.0 nM) reduced afferent diameter by 17 +/- 1% in untreated arterioles and by 6 +/- 2% during exposure to Y-27632. The P2X1 receptor agonist, alpha, beta-methylene ATP, reduced afferent arteriolar diameter by 8 +/- 1% but this response was eliminated during exposure to Y-27632. Western blot analysis confirms expression of the Rho-kinase signaling pathway. Thus, Rho-kinase may be important in pressure-mediated autoregulatory adjustments in preglomerular resistance and responsiveness to angiotensin II and autoregulatory P2X1 receptor agonists.
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Affiliation(s)
- Edward W Inscho
- Department of Physiology, Medical College of Georgia, 1120 15th St., Augusta, Georgia 30912-3000, USA.
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Affiliation(s)
- Edward W Inscho
- Department of Physiology, Medical College of Georgia, 1120 15th St, Augusta, GA 30912-3000, USA.
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Belin de Chantemèle EJ, Retailleau K, Pinaud F, Vessières E, Bocquet A, Guihot AL, Lemaire B, Domenga V, Baufreton C, Loufrani L, Joutel A, Henrion D. Notch3 is a major regulator of vascular tone in cerebral and tail resistance arteries. Arterioscler Thromb Vasc Biol 2008; 28:2216-24. [PMID: 18818417 DOI: 10.1161/atvbaha.108.171751] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Notch3, a member of the evolutionary conserved Notch receptor family, is primarily expressed in vascular smooth muscle cells. Genetic studies in human and mice revealed a critical role for Notch3 in the structural integrity of distal resistance arteries by regulating arterial differentiation and postnatal maturation. METHODS AND RESULTS We investigated the role of Notch3 in vascular tone in small resistance vessels (tail and cerebral arteries) and large (carotid) arteries isolated from Notch3-deficient mice using arteriography. Passive diameter and compliance were unaltered in mutant arteries. Similarly, contractions to phenylephrine, KCl, angiotensin II, and thromboxane A2 as well as dilation to acetylcholine or sodium nitroprusside were unaffected. However, Notch3 deficiency induced a dramatic reduction in pressure-induced myogenic tone associated with a higher flow (shear stress)-mediated dilation in tail and cerebral resistance arteries only. Furthermore, RhoA activity and myosin light chain phosphorylation, measured in pressurized tail arteries, were significantly reduced in Notch3KO mice. Additionally, myogenic tone inhibition by the Rho kinase inhibitor Y27632 was attenuated in mutant tail arteries. CONCLUSIONS Notch3 plays an important role in the control of vascular mechano-transduction, by modulating the RhoA/Rho kinase pathway, with opposite effects on myogenic tone and flow-mediated dilation in the resistance circulation.
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Kashihara T, Nakayama K, Ishikawa T. Distinct Roles of Protein Kinase C Isoforms in Myogenic Constriction of Rat Posterior Cerebral Arteries. J Pharmacol Sci 2008; 108:446-54. [DOI: 10.1254/jphs.08184fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Abstract
Rho kinases (ROCKs) are the first and the best-characterized effectors of the small G-protein RhoA. In addition to their effect on actin organization, or through this effect, ROCKs have been found to regulate a wide range of fundamental cell functions such as contraction, motility, proliferation, and apoptosis. Abnormal activation of the RhoA/ROCK pathway has been observed in major cardiovascular disorders such as atherosclerosis, restenosis, hypertension, pulmonary hypertension, and cardiac hypertrophy. This review, based on recent molecular, cellular, and animal studies, focuses on the current understanding of ROCK signaling and its roles in cardiovascular physiology and pathophysiology.
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Affiliation(s)
- Gervaise Loirand
- INSERM U-533-Institut du Thorax, Faculté des Sciences, Nantes, France
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Büssemaker E, Pistrosch F, Förster S, Herbrig K, Gross P, Passauer J, Brandes RP. Rho kinase contributes to basal vascular tone in humans: role of endothelium-derived nitric oxide. Am J Physiol Heart Circ Physiol 2007; 293:H541-7. [PMID: 17384125 DOI: 10.1152/ajpheart.00770.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our objective was to determine the role of the Rho-associated kinase (ROK) for the regulation of FBF (FBF) and to unmask a potential role of ROK for the regulation of endothelium-derived nitric oxide (NO). Moreover, the effect of fasudil on the constrictor response to endothelin-1 was recorded. Regarding background, phosphorylation of the myosin light chain (MLC) determines the calcium sensitivity of the contractile apparatus. MLC phosphorylation depends on the activity of the MLC kinase and the MLC phosphatase. The latter enzyme is inhibited through phosphorylation by ROK. ROK has been suggested to inhibit NO generation, possibly via the inhibition of the Akt pathway. In this study, the effect of intra-arterial infusion of the ROK inhibitor fasudil on FBF in 12 healthy volunteers was examined by venous occlusion plethysmography. To unmask the role of NO, fasudil was infused during NO clamp. As a result, fasudil markedly increased FBF in a dose-dependent manner from 2.34 ± 0.21 to 6.96 ± 0.93 ml/100 ml forearm volume at 80 μg/min ( P < 0.001). At 1,600 μg/min, fasudil reduced systolic, diastolic, and mean arterial pressure while increasing heart rate. Fasudil abolished the vasoconstrictor effect of endothelin-1. The vascular response to fasudil (80 μmol/min) was blunted during NO clamp (104 ± 18% vs. 244 ± 48% for NO clamp + fasudil vs. fasudil alone; data as ratio between infused and noninfused arm with baseline = 0%, P < 0.05). In conclusion, 1) basal peripheral and systemic vascular tone depends on ROK; 2) a significant portion of fasudil-induced vasodilation is mediated by NO, suggesting that vascular bioavailable NO is negatively regulated by ROK; and 3) the constrictor response to endothelin involves the activation of ROK.
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Affiliation(s)
- E Büssemaker
- Medizinische Klinik III, Nephrologie, University of Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
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Potocnik SJ, Jenkins N, Murphy TV, Hill MA. Membrane cholesterol depletion with beta-cyclodextrin impairs pressure-induced contraction and calcium signalling in isolated skeletal muscle arterioles. J Vasc Res 2007; 44:292-302. [PMID: 17406121 DOI: 10.1159/000101451] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2006] [Accepted: 12/15/2006] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Given evidence for clustering of signalling molecules and ion channels in cholesterol-rich membrane domains, the involvement of such structures in arteriolar smooth muscle mechanotransduction was examined. METHOD To determine the contribution of smooth muscle cholesterol-rich membrane domains to the myogenic response, isolated arterioles were exposed to the cholesterol-depleting agent beta-cyclodextrin (1-10 mM) in the absence and presence of excess exogenous cholesterol. RESULTS beta-Cyclodextrin significantly impaired pressure-induced vasoconstriction, while excess cholesterol attenuated this effect. Impaired myogenic constriction was evident in de-endothelialized vessels, indicating an action at the level of smooth muscle. beta-Cyclodextrin treatment uncoupled increases in intracellular Ca(2+) from myogenic constriction and depleted intracellular Ca(2+) stores consistent with a loss of connectivity between plasma membrane and sarcoplasmic reticulum signalling. However, beta-cyclodextrin-treated arterioles showed unaltered constrictor responses to KCl and phenylephrine. Electron microscopy verified that beta-cyclodextrin caused a decrease in caveolae, while confirmation of smooth muscle containing caveolae was obtained by immunostaining for caveolin-1. Viability of beta-cyclodextrin-treated arterioles was confirmed by agonist sensitivity and propidium iodide nuclear staining. CONCLUSION The data suggest that smooth muscle cholesterol-rich membrane domains contribute to the myogenic response. Further studies are required to determine whether this relates to specific mechanosensory events or generalized alterations in membrane function.
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Affiliation(s)
- Simon J Potocnik
- Microvascular Biology Group, School of Medical Sciences, RMIT University, Bundoora, Australia.
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Hill MA, Davis MJ. Coupling a change in intraluminal pressure to vascular smooth muscle depolarization: still stretching for an explanation. Am J Physiol Heart Circ Physiol 2007; 292:H2570-2. [PMID: 17384129 DOI: 10.1152/ajpheart.00331.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Michael A Hill
- Dalton Cardiovascular Research Center, Department of Medical Pharmacology and Physiology, University of Missouri, 134 Research Park Dr., Columbia, MO 65211, USA.
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Ito I, Jarajapu YPR, Grant MB, Knot HJ. Characteristics of myogenic tone in the rat ophthalmic artery. Am J Physiol Heart Circ Physiol 2007; 292:H360-8. [PMID: 16920804 DOI: 10.1152/ajpheart.00630.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pressure-induced constriction in the rat ophthalmic artery was characterized. Ophthalmic arteries were isolated, cannulated in an arteriograph, and pressurized. Arteries developed 25% constriction at 70 mmHg of intraluminal pressure. Arteries maintained almost similar diameter over the range of pressures 50–210 mmHg, and forced dilatation was observed at pressures >210 mmHg. Denudation of endothelium increased the sensitivity of arteries to pressure-induced constriction, and significantly higher myogenic tone was observed in the pressure range of 10–100 mmHg. Indomethacin and cyclooxygenase-2 inhibition by SC-236 decreased myogenic tone, whereas cyclooxygenase-1 inhibition by SC-560 potentiated myogenic tone in a lower concentration range and decreased at a higher concentration. Pressure-induced constriction was completely blocked by 1 μM nifedipine. Phospholipase C inhibition by 6 μM U-73122 decreased myogenic tone by 39%, whereas PKC inhibitor GF-109203X (3 μM) had no effect. Constriction to phenylephrine was significantly decreased by U-73122 (1 μM) and GF-109203X (3 μM) at an intraluminal pressure of 10 mmHg. Rho-kinase inhibition by Y-27632 (30 μM) and HA-1077 (30 μM) decreased myogenic tone by 75% and 73%, respectively, and 1 μM Y-27632 significantly decreased myogenic tone developed in response to graded increases in pressure. These results suggest that rat ophthalmic artery has an efficient pressure-dependent autoregulatory function that is modulated by endothelium. Contribution of phospholipase C-activation to myogenic tone is minimal, whereas Rho-kinase activation plays a predominant role in the myogenic reactivity in this artery.
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Affiliation(s)
- Isamu Ito
- Wake Forest Institute of Regenerative Medicine, Wake Forest Univ. Baptist Medical Hospital, Medical Center Blvd., Winston-Salem, NC 27157, USA
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Ito S, Kume H, Oguma T, Ito Y, Kondo M, Shimokata K, Suki B, Naruse K. Roles of stretch-activated cation channel and Rho-kinase in the spontaneous contraction of airway smooth muscle. Eur J Pharmacol 2006; 552:135-42. [PMID: 17026989 DOI: 10.1016/j.ejphar.2006.08.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 08/03/2006] [Accepted: 08/23/2006] [Indexed: 12/30/2022]
Abstract
In guinea pigs, it is well-known that mechanical stretch of airway smooth muscle exhibits spontaneous tone which is mediated by cyclooxygenase (COX) activation. We tested the hypothesis that this spontaneous contraction of airway smooth muscle is mediated by stretch-activated non-selective cation channels and the Rho/Rho-kinase pathway, as well as COX-2 using a pharmacological approach. Isometric force and intracellular Ca(2+) concentrations ([Ca(2+)](i)) were assessed in isolated guinea pig tracheal smooth muscle tissues. The samples were stretched to a given level and the muscle behavior was monitored under isometric conditions. We observed an increase in [Ca(2+)](i) and subsequent force generation over a 15-min period. The augmented [Ca(2+)](i) and spontaneous contraction due to the stretch were markedly attenuated by application of Gd(3+), an inhibitor of stretch-activated channels, and removal of extracellular Ca(2+). In contrast, nifedipine only had a mild inhibitory effect on the contraction. (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexane-carboxamide (Y-27632; a Rho-kinase inhibitor) abolished the spontaneous contraction with no changes in [Ca(2+)](i). Simvastatin, which down-regulates Rho activity, also significantly inhibited the contraction. Moreover, indomethacin, an inhibitor of COX-1 and -2, and N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398; a COX-2 inhibitor) abolished the stretch-induced contraction without affecting [Ca(2+)](i), whereas the inhibitory effect of 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole (SC560; a COX-1 inhibitor) on the contraction was much less. These findings demonstrated that Ca(2+) entry via stretch-activated channels, the Rho/Rho-kinase pathway, and COX-2 are involved in the mechanotransduction in guinea pig tracheal smooth muscle. Additionally, while the Rho/Rho-kinase pathway and COX-2 regulate the spontaneous contraction independently of [Ca(2+)](i), COX-1 is not involved in the stretch-induced force generation.
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Affiliation(s)
- Satoru Ito
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Parker TA, Roe G, Grover TR, Abman SH. Rho kinase activation maintains high pulmonary vascular resistance in the ovine fetal lung. Am J Physiol Lung Cell Mol Physiol 2006; 291:L976-82. [PMID: 16815887 DOI: 10.1152/ajplung.00512.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanisms that maintain high pulmonary vascular resistance (PVR) in the fetal lung are poorly understood. Activation of the Rho kinase signal transduction pathway, which promotes actin-myosin interaction in vascular smooth muscle cells, is increased in the pulmonary circulation of adult animals with experimental pulmonary hypertension. However, the role of Rho kinase has not been studied in the fetal lung. We hypothesized that activation of Rho kinase contributes to elevated PVR in the fetus. To address this hypothesis, we studied the pulmonary hemodynamic effects of brief (10 min) intrapulmonary infusions of two specific Rho kinase inhibitors, Y-27632 (15-500 microg) and HA-1077 (500 microg), in chronically prepared late-gestation fetal lambs (n = 9). Y-27632 caused potent, dose-dependent pulmonary vasodilation, lowering PVR from 0.67 +/- 0.18 to 0.16 +/- 0.02 mmHg x ml(-1) x min(-1) (P < 0.01) at the highest dose tested without lowering systemic arterial pressure. Despite brief infusions, Y-27632-induced pulmonary vasodilation was sustained for 50 min. HA-1077 caused a similar fall in PVR, from 0.39 +/- 0.03 to 0.19 +/- 0.03 (P < 0.05). To study nitric oxide (NO)-Rho kinase interactions in the fetal lung, we tested the effect of Rho kinase inhibition on pulmonary vasoconstriction caused by inhibition of endogenous NO production with nitro-L-arginine (L-NA; 15-30 mg), a selective NO synthase antagonist. L-NA increased PVR by 127 +/- 73% above baseline under control conditions, but this vasoconstrictor response was completely prevented by treatment with Y-27632 (P < 0.05). We conclude that the Rho kinase signal transduction pathway maintains high PVR in the normal fetal lung and that activation of the Rho kinase pathway mediates pulmonary vasoconstriction after NO synthase inhibition. We speculate that Rho kinase plays an essential role in the normal fetal pulmonary circulation and that Rho kinase inhibitors may provide novel therapy for neonatal pulmonary hypertension.
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Affiliation(s)
- Thomas A Parker
- Pediatric Heart Lung Center and Section of Neonatology, University of Colorado School of Medicine, Denver, USA.
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Keller M, Lidington D, Vogel L, Peter BF, Sohn HY, Pagano PJ, Pitson S, Spiegel S, Pohl U, Bolz SS. Sphingosine kinase functionally links elevated transmural pressure and increased reactive oxygen species formation in resistance arteries. FASEB J 2006; 20:702-4. [PMID: 16476702 DOI: 10.1096/fj.05-4075fje] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Myogenic vasoconstriction, an intrinsic response to elevated transmural pressure (TMP), requires the activation of sphingosine kinase (Sk1) and the generation of reactive oxygen species (ROS). We hypothesized that pressure-induced Sk1 signaling and ROS generation are functionally linked. Using a model of cannulated resistance arteries isolated from the hamster gracilis muscle, we monitored vessel diameter and smooth muscle cell (SMC) Ca2+i (Fura-2) or ROS production (dichlorodihydrofluorescein). Elevation of TMP stimulated the translocation of a GFP-tagged Sk1 fusion protein from the cytosol to the plasma membrane, indicative of enzymatic activation. Concurrently, elevation of TMP initiated a rapid and transient production of ROS, which was enhanced by expression of wild-type Sk1 (hSk(wt)) and inhibited by its dominant-negative mutant (hSk(G82D)). Exogenous sphingosine-1-phosphate (S1P) also stimulated ROS generation is isolated vessels. Chemical (1 micromol/L DPI), peptide (gp91ds-tat/gp91ds), and genetic (N17Rac) inhibition strategies indicated that NADPH oxidase was the source of the pressure-induced ROS. NADPH oxidase inhibition attenuated myogenic vasoconstriction and reduced the apparent Ca2+ sensitivity of the SMC contractile apparatus, without affecting Ca2+-independent, RhoA-mediated vasoconstriction in response to exogenous S1P. Our results indicate a mandatory role for Sk1/S1P in mediating pressure-induced, NADPH oxidase-derived ROS formation. In turn, ROS generation appears to increase Ca2+ sensitivity, necessary for full myogenic vasoconstriction.
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Affiliation(s)
- Matthias Keller
- Institute of Physiology, Ludwig-Maximilians-University, Munich, Germany
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Gokina NI, Park KM, McElroy-Yaggy K, Osol G. Effects of Rho kinase inhibition on cerebral artery myogenic tone and reactivity. J Appl Physiol (1985) 2005; 98:1940-8. [PMID: 15626753 DOI: 10.1152/japplphysiol.01104.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several recent studies have implicated the RhoA-Rho kinase pathway in arterial myogenic behavior. The goal of this study was to determine the effects of Rho kinase inhibition (Y-27632) on cerebral artery calcium and diameter responses as a function of transmural pressure. Excised segments of rat posterior cerebral arteries (100–200 μm) were cannulated and pressurized in an arteriograph at 37°C. Increasing pressure from 10 to 60 mmHg triggered an elevation of cytosolic calcium concentration ([Ca2+]i) from 113 ± 9 to 199 ± 12 nM and development of myogenic tone. Further elevation of pressure to 120 mmHg induced only a minor additional increase in [Ca2+]iand constriction. Y-27632 (0.3–10 μM) inhibited myogenic tone in a concentration-dependent manner at 60 and 120 mmHg with comparable efficacy; conversely, sensitivity was decreased at 120 vs. 60 mmHg (50% inhibitory concentration: 2.5 ± 0.3 vs. 1.4 ± 0.1 μM; P < 0.05). Dilation was accompanied by further increases in [Ca2+]iand an enhancement of Ca2+oscillatory activity. Y-27632 also effectively dilated the vessels permeabilized with α-toxin in a concentration-dependent manner. However, dilator effects of Y-27632 at low concentrations were larger at 60 vs. 100 mmHg. In summary, the results support a significant role for RhoA-Rho kinase pathway in cerebral artery mechanotransduction of pressure into sustained vasoconstriction (myogenic tone and reactivity) via mechanisms that augment smooth muscle calcium sensitivity. Potential downstream events may involve inhibition of myosin phosphatase and/or stimulation of actin polymerization, both of which are associated with increased smooth muscle force production.
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Affiliation(s)
- Natalia I Gokina
- Department of Obstetrics and Gynecology, The University of Vermont, College of Medicine, Burlington, VT 05405, USA.
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Dubroca C, You D, Lévy BI, Loufrani L, Henrion D. Involvement of RhoA/Rho kinase pathway in myogenic tone in the rabbit facial vein. Hypertension 2005; 45:974-9. [PMID: 15837833 PMCID: PMC2231527 DOI: 10.1161/01.hyp.0000164582.63421.2d] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Myogenic tone (MT), a fundamental stretch-sensitive vasoconstrictor property of resistance arteries and veins, is a key determinant of local blood flow regulation. We evaluated the pathways involved in MT development. The role of the RhoA/Rho kinase, p38 MAP kinase, and HSP27 in MT was investigated in the rabbit facial vein (RFV), previously shown to possess MT at a pressure level equivalent to 20 mm Hg. Venous MT is poorly understood, although venous diseases affect a large proportion of the population. Stretched RFV are characterized by a temperature-sensitive MT, which is normal at 39 degrees C but fails to develop at 33 degrees C. This allows for the discrimination of the pathways involved in MT from the multiple pathways activated by stretch. Isolated RFV segments were mounted in organ baths and stretched. Temperature was then set at 33 degrees C or 39 degrees C. MT was associated to the translocation of RhoA to the plasma membrane and the Rho kinase inhibitor Y27632 decreased stretch-induced MT by 93.1+/-4.9%. MT was also associated to an increase in p38 (131.0+/-12.5% at 39 degrees C versus 100% at 33 degrees C) and HSP27 phosphorylation (196.1+/-13.3% versus 100%), and the p38 MAP kinase inhibitor SB203580 decreased MT by 36.5+/-8.1%. (39 degrees C, compared with RFV stretched at 33 degrees C). Finally, phosphorylation of p38 was blocked by Y27632 and HSP27 phosphorylation was inhibited by SB203580 and Y27632. Thus, MT and the associated p38 and HSP27 phosphorylation seem to depend on RhoA/Rho kinase activation in stretch RFV.
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Affiliation(s)
- Caroline Dubroca
- Biologie et physiologie moléculaire du vaisseau
INSERM : U541Hôpital Lariboisière
41, boulevard de la chapelle
75475 Paris Cedex 10,FR
| | - Dong You
- Biologie et physiologie moléculaire du vaisseau
INSERM : U541Hôpital Lariboisière
41, boulevard de la chapelle
75475 Paris Cedex 10,FR
| | - Bernard I. Lévy
- Biologie et physiologie moléculaire du vaisseau
INSERM : U541Hôpital Lariboisière
41, boulevard de la chapelle
75475 Paris Cedex 10,FR
| | - Laurent Loufrani
- CRMC, Circulations régionales et micro circulation
CNRS : UMR6188Université d'AngersUER de Médecine
rue Haute de Reculée
49045 ANGERS CEDEX 01,FR
| | - Daniel Henrion
- CRMC, Circulations régionales et micro circulation
CNRS : UMR6188Université d'AngersUER de Médecine
rue Haute de Reculée
49045 ANGERS CEDEX 01,FR
- * Correspondence should be adressed to: Daniel Henrion
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Abstract
Resistance arteries are able to adapt to physiological and pathophysiological stimuli to maintain adequate perfusion according to the metabolic demand of the tissue. Although vasomotor control allows rapid adaptation of lumen diameter, vascular remodeling constitutes an active process that occurs in response to long-term alterations of hemodynamic parameters. Unfortunately, this initially adaptive process contributes to the pathology of vascular diseases. Recent studies have demonstrated the participation of Rho protein signaling pathways in several cardiovascular pathologies including hypertension, coronary artery spasm, effort angina, atherosclerosis, and restenosis. Functional analyses have further revealed that RhoA-dependent pathways are involved in excessive contraction, migration, and proliferation associated with arterial diseases. The present review focuses on the role of Rho proteins, in particular RhoA, in vascular smooth muscle cells and the involvement of Rho-dependent signaling pathways in resistance artery remodeling, more particularly in relation to hypertension.
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Martinez-Lemus LA, Crow T, Davis MJ, Meininger GA. alphavbeta3- and alpha5beta1-integrin blockade inhibits myogenic constriction of skeletal muscle resistance arterioles. Am J Physiol Heart Circ Physiol 2005; 289:H322-9. [PMID: 15722407 DOI: 10.1152/ajpheart.00923.2003] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In isolated resistance arterioles with spontaneous tone, ligation of alpha4beta1- and alpha5beta1-integrins induces vasoconstriction whereas ligation of alphavbeta3-integrin induces vasodilation. However, whether integrins directly participate in myogenic constriction to pressure elevation is not known. To answer this question, isolated rat skeletal muscle arterioles were exposed to step increments in pressure in the absence or presence of peptides and function-blocking antibodies known to bind alpha4beta1-, alpha5beta1-, or alphavbeta3-integrins while vessel diameter was continually monitored. Myogenic constriction, as assessed by the ability of isolated arterioles to reduce their diameter in response to two consecutive increments in intraluminal pressure (90-110 and 110-130 cmH2O), was not affected by treatment with any of the control peptides (RAD, LEV), a control antibody (anti-rat major histocompatibility complex), an alpha4beta1-integrin-binding peptide (LDV), or an anti-alpha4-integrin antibody. In contrast, alpha5beta1-integrin blockade with either anti-alpha5- or anti-beta1-integrin antibody caused a significant inhibition of myogenic constriction. Also, both RGD peptide and anti-beta3-integrin antibody inhibited myogenic constriction. These results indicate that alpha5beta1- and alphavbeta3-integrins are necessary for myogenic constriction and further suggest that integrins are part of the mechanosensory apparatus responsible for the ability of vascular smooth muscle cells to detect and/or respond to changes in intraluminal pressure.
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Affiliation(s)
- Luis A Martinez-Lemus
- Cardiovascular Research Inst., Dept. of Medical Physiology, Texas A&M Univ. Health Science Center, 336 Reynolds Medical Bldg., College Station, TX 77843-1114, USA
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Korzick DH, Laughlin MH, Bowles DK. Alterations in PKC signaling underlie enhanced myogenic tone in exercise-trained porcine coronary resistance arteries. J Appl Physiol (1985) 2004; 96:1425-32. [PMID: 14672961 DOI: 10.1152/japplphysiol.01077.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The intracellular mechanisms underlying enhanced myogenic contraction (MC) in coronary resistance arteries (CRAs) from exercise-trained (EX) pigs have not been established. The purpose of this study was to test the hypothesis that exercise-induced alterations in protein kinase C (PKC) signaling underlie enhanced MC. Furthermore, we sought to determine whether modulation of intracellular Ca2+signaling by PKC underlies enhanced MC in EX animals. Male Yucatan miniature swine were treadmill trained ( n = 7) at ∼75% of maximal O2uptake for 16 wk (6 miles/h, 60 min) or remained sedentary (SED, n = 6). Diameter measurements in response to intraluminal pressure (60, 75, and 90 cmH2O) or 60 mM KCl were determined in single, cannulated CRAs (∼100 μm ID) with and without the PKC inhibitor chelerythrine (CE, 1 μM). Confocal imaging of Ca2+signaling [myogenic Ca2+(Cam)] was also performed in CRAs of similar internal diameter after abluminal loading of the Ca2+indicator dye fluo 4 (1 μM, 37°C, 30 min). We observed significantly greater MC in CRAs isolated from EX than from SED animals at 90 cmH2O, as well as greater reductions in MC after CE at all pressures studied. At intraluminal pressures of 75 and 90 cmH2O, CE produced greater decreases in Camin CRAs from EX than from SED animals (64% vs. 25%, P < 0.05). Inhibition of KCl constriction and Camby CE was also greater in EX animals ( P < 0.05). Western blotting revealed significant increases in Ca2+-dependent PKC-α (∼50%) but not Ca2+-independent PKC-ϵ levels in CRAs isolated from EX animals ( P < 0.05). We also observed significant group differences in phosphorylated PKC-α levels. Finally, voltage-gated Ca2+current (VGCC) was effectively blocked by CE, bisindolylmaleimide, and staurosporine in isolated smooth muscle cells from CRAs, providing evidence for a mechanistic link between VGCCs and PKC in our experimental paradigm. These results suggest that enhanced MC in CRAs from EX animals involves PKC-dependent modulation of intracellular Ca2+, including regulation of VGCCs.
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Affiliation(s)
- D H Korzick
- Department of Biomedical Sciences,University of Missouri, Columbia, MO 65211, USA
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Heaps CL, Parker JL, Sturek M, Bowles DK. Altered calcium sensitivity contributes to enhanced contractility of collateral-dependent coronary arteries. J Appl Physiol (1985) 2004; 97:310-6. [PMID: 14978011 PMCID: PMC3529197 DOI: 10.1152/japplphysiol.01400.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Coronary arteries distal to chronic occlusion exhibit enhanced vasoconstriction and impaired relaxation compared with nonoccluded arteries. In this study, we tested the hypotheses that an increase in peak Ca(2+) channel current density and/or increased Ca(2+) sensitivity contributes to altered contractility in collateral-dependent coronary arteries. Ameroid occluders were surgically placed around the proximal left circumflex coronary artery (LCX) of female miniature swine. Segments of epicardial arteries ( approximately 1 mm luminal diameter) were isolated from the LCX and nonoccluded left anterior descending (LAD) arteries 24 wk after Ameroid placement. Contractile responses to depolarization (10-100 mM KCl) were significantly enhanced in LCX compared with size-matched LAD arterial rings [concentration of KCl causing 50% of the maximal contractile response (EC(50)); LAD = 41.7 +/- 2.3, LCX = 34.3 +/- 2.7 mM]. However, peak Ca(2+) channel current was not altered in isolated smooth muscle cells from LCX compared with LAD (-5.29 +/- 0.42 vs. -5.68 +/- 0.55 pA/pF, respectively). Furthermore, whereas half-maximal activation of Ca(2+) channel current occurred at nearly the same membrane potential in LAD and LCX, half-maximal inactivation was shifted to a more positive membrane potential in LCX cells. Simultaneous measures of contractile tension and intracellular free Ca(2+) (fura 2) levels in arterial rings revealed that significantly more tension was produced per unit change in fura 2 ratio in LCX compared with LAD in response to KCl but not during receptor-agonist stimulation with endothelin-1. Taken together, our data indicate that coronary arteries distal to chronic occlusion display increased Ca(2+) sensitivity in response to high KCl-induced depolarization, independent of changes in whole cell peak Ca(2+) channel current. Unaltered Ca(2+) sensitivity in endothelin-stimulated arteries suggests more than one mechanism regulating Ca(2+) sensitization in coronary smooth muscle.
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Affiliation(s)
- Cristine L Heaps
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA.
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Büyükafşar K, Arikan O, Ark M, Seçilmiş A, Un I, Singirik E. Rho-kinase expression and its contribution to the control of perfusion pressure in the isolated rat mesenteric vascular bed. Eur J Pharmacol 2004; 485:263-8. [PMID: 14757149 DOI: 10.1016/j.ejphar.2003.11.076] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Rho-kinase expression was investigated in the rat mesenteric artery and the effects of its inhibitors, (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride monohydrate (Y-27632) and fasudil (HA-1077), were examined on the increase in perfusion pressure induced by two different receptor agonists, namely the alpha-adrenoceptor agonist, phenylephrine and, the endothelin ET(A) and ET(B) receptor agonist, endothelin-1. Y-27632 and fasudil produced a concentration-dependent decrease in perfusion pressure. There was no difference between the concentration-response lines of these two inhibitors. The maximum decrease in the perfusion pressure induced by 10(-5) M Y-27632 was 85.8+/-3.7% when the tone was increased by phenylephrine. However, it was 48.1+/-5.4% (P<0.001) when the perfusion pressure was elevated by endothelin-1. Saponin perfusion (100 mg l(-1), for 10 min), which abolished acetylcholine-induced relaxation, did not significantly modify the Y-27632-elicited relaxation. Western blot analysis revealed that rat mesenteric artery expresses Rho-kinase protein with a molecular weight of approximately 160 kDa. These results show that Rho-kinase enzyme is expressed in rat mesenteric artery and that it contributes to the control of vascular resistance. Moreover, endothelium removal had no marked effect on the vasodilatation induced by Y-27632. In addition, the endothelin-1-induced vasoconstriction was more resistant to the Rho-kinase inhibitors than was that induced by phenylephrine, probably because excitatory endothelin receptors are associated with this signal transduction pathway at a different level from that of alpha-adrenoceptors.
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Affiliation(s)
- Kansu Büyükafşar
- Department of Pharmacology, Medical Faculty Mersin University, Campus Yenişehir 33169, Mersin, Turkey.
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Hosaka K, Mizuno R, Ohhashi T. Rho-Rho kinase pathway is involved in the regulation of myogenic tone and pump activity in isolated lymph vessels. Am J Physiol Heart Circ Physiol 2003; 284:H2015-25. [PMID: 12742825 DOI: 10.1152/ajpheart.00763.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To evaluate whether or not Rho-Rho kinase pathway is involved in the regulation of mechanical activity of lymph vessels, effects of Y-27632 and okadaic acid on lymph pump activity and myogenic, pressure- and agonist-induced tone were examined in isolated rat lymph vessels. Y-27632 caused a significant dilation with a cessation of the lymph pump activity. Y-27632 also produced a dose-related dilation of the lymph vessels precontracted by norepinephrine (NE)-, U-46619- or 80 mM KCl. Okadaic acid significantly constricted the lymph vessels and reduced the frequency of the lymph pump activity. Okadaic acid also produced a dose-related constriction of the lymph vessels precontracted by NE or U-46619. The Y-27632-induced decrease of the frequency of lymph pump activity was significantly reversed by the pretreatment with okadaic acid. In the presence of Y-27632, the pressure-mediated tone of the lymph vessel was significantly decreased. On the other hand, okadaic acid significantly increased the pressure-mediated tone. These findings suggest that Rho kinase and myosin phosphatase activity in lymphatic smooth muscles may contribute to the regulation of lymph pump activity and may be also involved in the control of myogenic pressure- and agonist-induced tone.
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Affiliation(s)
- Kayoko Hosaka
- The First Department of Physiology, Shinshu University School of Medicine, Shinshu University Graduate School of Medicine, Matsumoto 390-8621, Japan
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Affiliation(s)
| | - Joseph Brayden
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont 05405-0001
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