1
|
Naser N, Lonj CK, Rikard-Bell M, Sandow SL, Murphy TV. Advanced glycated end-products inhibit dilation through constitutive endothelial RAGE and Nox1/4 in rat isolated skeletal muscle arteries. Microcirculation 2024; 31:e12837. [PMID: 37985248 DOI: 10.1111/micc.12837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/17/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023]
Abstract
OBJECTIVE This study investigated the actions of advanced glycated end-products (AGE), their receptors (RAGE), and NAD(P)H oxidase (Nox) subtypes 1, 2, and 4 on mechanisms of endothelium-dependent dilation of the rat cremaster muscle artery (CMA). METHODS Immunofluorescence studies were used to examine expression of RAGE in rat arteries. ROS accumulation was measured using luminescence and fluorescence assays. Functional studies were performed using pressure myography. RESULTS High levels of RAGE expression were shown in the endothelial cells of the CMA, compared with low endothelial expression in middle cerebral and mesenteric arteries and the aorta. Exogenous AGE (in vitro glycated bovine serum albumin) stimulated H2O2 accumulation in CMA, which was prevented by the RAGE antagonist FPS-ZM1, the NAD(P)H oxidase (Nox) inhibitor apocynin and inhibited by the Nox1/4 inhibitor setanaxib, but not the Nox2 inhibitor GSK2795039. In functional studies, AGE inhibited vasodilation of CMA stimulated by acetylcholine, sodium nitroprusside, and the BKCa activator NS1619, but not adenosine-induced dilation. FPS-ZM1, apocynin, and setanaxib prevented the inhibitory effects of AGE on responses to acetylcholine and NS-1619. CONCLUSION These observations suggest RAGE are constitutively expressed in the endothelium of the rat CMA and may be activated by AGE to stimulate Nox1/4 and ROS formation with resulting inhibition of NO and BKCa-mediated endothelium-dependent dilation.
Collapse
Affiliation(s)
- Nadim Naser
- Physiology, School of Biomedical Sciences, UNSW Sydney, Sydney, Australia
| | - Chenchel K Lonj
- Physiology, School of Biomedical Sciences, UNSW Sydney, Sydney, Australia
| | - Matthew Rikard-Bell
- Physiology, School of Biomedical Sciences, UNSW Sydney, Sydney, Australia
- Townsville University Hospital, Townsville, Queensland, Australia
| | - Shaun L Sandow
- Biomedical Science, University of the Sunshine Coast, Maroochydore, Australia
- Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Timothy V Murphy
- Physiology, School of Biomedical Sciences, UNSW Sydney, Sydney, Australia
| |
Collapse
|
2
|
Carlton‐Carew SRE, Greenberg HZE, Connor EJ, Zadeh P, Greenwood IA, Albert AP. Stimulation of the calcium-sensing receptor induces relaxations of rat mesenteric arteries by endothelium-dependent and -independent pathways via BK Ca and K ATP channels. Physiol Rep 2024; 12:e15926. [PMID: 38281732 PMCID: PMC10822715 DOI: 10.14814/phy2.15926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 01/30/2024] Open
Abstract
Stimulation of the calcium-sensing receptor (CaSR) induces both vasoconstrictions and vasorelaxations but underlying cellular processes remain unclear. This study investigates expression and effect of stimulating the CaSR by increasing external Ca2+ concentration ([Ca2+ ]o ) on contractility of rat mesenteric arteries. Immunofluorescence studies showed expression of the CaSR in perivascular nerves, vascular smooth muscle cells (VSMCs), and vascular endothelium cells. Using wire myography, increasing [Ca2+ ]o from 1 to 10 mM induced vasorelaxations which were inhibited by the calcilytic Calhex-231 and partially dependent on a functional endothelium. [Ca2+ ]o -induced vasorelaxations were reduced by endothelial NO synthase (eNOS, L-NAME) and large conductance Ca2+ -activated K+ channels (BKCa , iberiotoxin), with their inhibitory action requiring a functional endothelium. [Ca2+ ]o -induced vasorelaxations were also markedly inhibited by an ATP-dependent K+ channel (KATP ) blocker (PNU37883), which did not require a functional endothelium to produce its inhibitory action. Inhibitor studies also suggested contributory roles for inward rectifying K+ channels (Kir ), Kv7 channels, and small conductance Ca2+ -activated K+ channels (SKCa ) on [Ca2+ ]o -induced vasorelaxations. These findings indicate that stimulation of the CaSR mediates vasorelaxations involving multiple pathways, including an endothelium-dependent pathway involving NO production and activation of BKCa channels and an endothelium-independent pathway involving stimulation of KATP channels.
Collapse
Affiliation(s)
- Simonette R. E. Carlton‐Carew
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| | - Harry Z. E. Greenberg
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| | - Eleanor J. Connor
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| | - Pooneh Zadeh
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| | - Iain A. Greenwood
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| | - Anthony P. Albert
- Vascular Biology Research Section, Molecular & Clinical Sciences Research InstituteSt. George's University of LondonLondonUK
| |
Collapse
|
3
|
Baldwin SN, Jepps TA, Greenwood IA. Cycling matters: Sex hormone regulation of vascular potassium channels. Channels (Austin) 2023; 17:2217637. [PMID: 37243715 PMCID: PMC10228406 DOI: 10.1080/19336950.2023.2217637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/07/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023] Open
Abstract
Sex hormones and the reproductive cycle (estrus in rodents and menstrual in humans) have a known impact on arterial function. In spite of this, sex hormones and the estrus/menstrual cycle are often neglected experimental factors in vascular basic preclinical scientific research. Recent research by our own laboratory indicates that cyclical changes in serum concentrations of sex -hormones across the rat estrus cycle, primary estradiol, have significant consequences for the subcellular trafficking and function of KV. Vascular potassium channels, including KV, are essential components of vascular reactivity. Our study represents a small part of a growing field of literature aimed at determining the role of sex hormones in regulating arterial ion channel function. This review covers key findings describing the current understanding of sex hormone regulation of vascular potassium channels, with a focus on KV channels. Further, we highlight areas of research where the estrus cycle should be considered in future studies to determine the consequences of physiological oscillations in concentrations of sex hormones on vascular potassium channel function.
Collapse
Affiliation(s)
- Samuel N Baldwin
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George’s University of London, London, UK
| |
Collapse
|
4
|
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: 40] [Impact Index Per Article: 40.0] [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.
Collapse
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
| |
Collapse
|
5
|
Ca 2+-Activated K + Channels and the Regulation of the Uteroplacental Circulation. Int J Mol Sci 2023; 24:ijms24021349. [PMID: 36674858 PMCID: PMC9867535 DOI: 10.3390/ijms24021349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/13/2023] Open
Abstract
Adequate uteroplacental blood supply is essential for the development and growth of the placenta and fetus during pregnancy. Aberrant uteroplacental perfusion is associated with pregnancy complications such as preeclampsia, fetal growth restriction (FGR), and gestational diabetes. The regulation of uteroplacental blood flow is thus vital to the well-being of the mother and fetus. Ca2+-activated K+ (KCa) channels of small, intermediate, and large conductance participate in setting and regulating the resting membrane potential of vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) and play a critical role in controlling vascular tone and blood pressure. KCa channels are important mediators of estrogen/pregnancy-induced adaptive changes in the uteroplacental circulation. Activation of the channels hyperpolarizes uteroplacental VSMCs/ECs, leading to attenuated vascular tone, blunted vasopressor responses, and increased uteroplacental blood flow. However, the regulation of uteroplacental vascular function by KCa channels is compromised in pregnancy complications. This review intends to provide a comprehensive overview of roles of KCa channels in the regulation of the uteroplacental circulation under physiological and pathophysiological conditions.
Collapse
|
6
|
Albrakati A. Caveolar disruption with methyl-β-cyclodextrin causes endothelium-dependent contractions in Wistar rat carotid arteries. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:63071-63080. [PMID: 35445923 DOI: 10.1007/s11356-022-20226-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
Caveolae are organizing centers for cellular signal transduction in endothelial cells (ED) and smooth muscle cells (SMCs) in the blood vessels. Myography was used to investigate the effects of a caveolar disruption using methyl-β-cyclodextrin (MBCD) on maxi-K channels in rat carotid arteries. Incubation of carotid segments with MBCD augmented contractions in response to BaK (chemical channel agonist) but not those induced by depolarizing high potassium physiological saline (KPSS). In contrast, incubation with cholesterol-saturated MBCD (Ch-MBCD) abolished the effects of MBCD. Mechanical removal of endothelial cells by MBCD triggered a small contraction in response to BaK. Incubation with nitroarginine methyl ester (L-NAME) inhibited nitric oxide (NO) release, causing increased contractions in response to BaK, and this effect was reversed by pretreatment with MBCD. These results suggest that MBCD inhibits endothelial NO release. Contrastingly, inhibition of maxi-K channels with iberiotoxin enhanced contractions in response to BaK. Likewise, L-NAME decreased the contractile effect of iberiotoxin, as in the ED-denuded arteries. Transmission electron microscopy (TEM) showed the presence and absence of caveolae in intact blood vessels before and after MBCD treatment, respectively, whereas histology confirmed ED removal after the treatment. Caveolar disruption using MBCD impairs ED-dependent relaxation by inhibiting the release of NO from the ED and altered the contractility of SMCs independent of the ED due to reduced contribution of maxi-K channels to the SMC membrane potential, causing depolarization and increasing carotid artery contraction. These findings might help to understand the physiological role of the maxi-K channels in rat carotid arteries.
Collapse
Affiliation(s)
- Ashraf Albrakati
- Department of Human Anatomy, College of Medicine, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
| |
Collapse
|
7
|
Jackson WF. Calcium-Dependent Ion Channels and the Regulation of Arteriolar Myogenic Tone. Front Physiol 2021; 12:770450. [PMID: 34819877 PMCID: PMC8607693 DOI: 10.3389/fphys.2021.770450] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/11/2021] [Indexed: 11/25/2022] Open
Abstract
Arterioles in the peripheral microcirculation regulate blood flow to and within tissues and organs, control capillary blood pressure and microvascular fluid exchange, govern peripheral vascular resistance, and contribute to the regulation of blood pressure. These important microvessels display pressure-dependent myogenic tone, the steady state level of contractile activity of vascular smooth muscle cells (VSMCs) that sets resting arteriolar internal diameter such that arterioles can both dilate and constrict to meet the blood flow and pressure needs of the tissues and organs that they perfuse. This perspective will focus on the Ca2+-dependent ion channels in the plasma and endoplasmic reticulum membranes of arteriolar VSMCs and endothelial cells (ECs) that regulate arteriolar tone. In VSMCs, Ca2+-dependent negative feedback regulation of myogenic tone is mediated by Ca2+-activated K+ (BKCa) channels and also Ca2+-dependent inactivation of voltage-gated Ca2+ channels (VGCC). Transient receptor potential subfamily M, member 4 channels (TRPM4); Ca2+-activated Cl− channels (CaCCs; TMEM16A/ANO1), Ca2+-dependent inhibition of voltage-gated K+ (KV) and ATP-sensitive K+ (KATP) channels; and Ca2+-induced-Ca2+ release through inositol 1,4,5-trisphosphate receptors (IP3Rs) participate in Ca2+-dependent positive-feedback regulation of myogenic tone. Calcium release from VSMC ryanodine receptors (RyRs) provide negative-feedback through Ca2+-spark-mediated control of BKCa channel activity, or positive-feedback regulation in cooperation with IP3Rs or CaCCs. In some arterioles, VSMC RyRs are silent. In ECs, transient receptor potential vanilloid subfamily, member 4 (TRPV4) channels produce Ca2+ sparklets that activate IP3Rs and intermediate and small conductance Ca2+ activated K+ (IKCa and sKCa) channels causing membrane hyperpolarization that is conducted to overlying VSMCs producing endothelium-dependent hyperpolarization and vasodilation. Endothelial IP3Rs produce Ca2+ pulsars, Ca2+ wavelets, Ca2+ waves and increased global Ca2+ levels activating EC sKCa and IKCa channels and causing Ca2+-dependent production of endothelial vasodilator autacoids such as NO, prostaglandin I2 and epoxides of arachidonic acid that mediate negative-feedback regulation of myogenic tone. Thus, Ca2+-dependent ion channels importantly contribute to many aspects of the regulation of myogenic tone in arterioles in the microcirculation.
Collapse
Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
8
|
Pinilla E, Sánchez A, Martínez MP, Muñoz M, García‐Sacristán A, Köhler R, Prieto D, Rivera L. Endothelial K Ca 1.1 and K Ca 3.1 channels mediate rat intrarenal artery endothelium-derived hyperpolarization response. Acta Physiol (Oxf) 2021; 231:e13598. [PMID: 33314681 DOI: 10.1111/apha.13598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/30/2022]
Abstract
AIM Endothelium-derived hyperpolarization (EDH)-mediated response plays an essential role in the control of kidney preglomerular circulation, but the identity of the K+ channels involved in this response is still controversial. We hypothesized that large- (KCa 1.1), intermediate- (KCa 3.1) and small (KCa 2.3) -conductance Ca2+ -activated K+ (KCa ) channels are expressed in the endothelium of the preglomerular circulation and participate in the EDH-mediated response. METHODS We study the functional expression of different K+ channels in non-cultured, freshly isolated native endothelial cells (ECs) of rat intrarenal arteries using immunofluorescence and the patch-clamp technique. We correlate this with vasorelaxant responses ex vivo using wire myography. RESULTS Immunofluorescence revealed the expression of KCa 1.1, KCa 3.1 and KCa 2.3 channels in ECs. Under voltage-clamp conditions, acetylcholine induced a marked increase in the outward currents in these cells, sensitive to the blockade of KCa 1.1, KCa 3.1 and KCa 2.3 channels respectively. Isometric myography experiments, under conditions of endothelial nitric oxide synthase and cyclooxygenase inhibition, showed that blockade either of KCa 1.1 or KCa 3.1 channels was able to reduce the endothelium-derived vasorelaxation of isolated interlobar arteries, while their combined blockade completely abolished it. In contrast, blockade of KCa 2.3 channels did not reduce this vasorelaxant response, despite being functionally expressed in the endothelial cells. CONCLUSION This study shows that KCa 1.1 and KCa 3.1 channels are functionally expressed at the renal vascular endothelium and play a central role in the EDH-mediated relaxation of kidney preglomerular arteries, which is important in the control of renal blood flow and glomerular filtration rate.
Collapse
Affiliation(s)
- Estéfano Pinilla
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology Aarhus University Aarhus Denmark
| | - Ana Sánchez
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
| | - María P. Martínez
- Department of Compared Anatomy and Pathological Anatomy, Faculty of Veterinary Complutense University of Madrid Madrid Spain
| | - Mercedes Muñoz
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
| | - Albino García‐Sacristán
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
| | - Ralf Köhler
- Aragonese Agency for Investigation and Development & IACS/IIS Translational ResearchMiguel Servet Hospital Zaragoza Spain
| | - Dolores Prieto
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
| | - Luis Rivera
- Departament of Physiology, Faculty of Pharmacy Complutense University of Madrid Madrid Spain
| |
Collapse
|
9
|
Ca 2+ homeostasis in brain microvascular endothelial cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:55-110. [PMID: 34253298 DOI: 10.1016/bs.ircmb.2021.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Blood brain barrier (BBB) is formed by the brain microvascular endothelial cells (BMVECs) lining the wall of brain capillaries. Its integrity is regulated by multiple mechanisms, including up/downregulation of tight junction proteins or adhesion molecules, altered Ca2+ homeostasis, remodeling of cytoskeleton, that are confined at the level of BMVECs. Beside the contribution of BMVECs to BBB permeability changes, other cells, such as pericytes, astrocytes, microglia, leukocytes or neurons, etc. are also exerting direct or indirect modulatory effects on BBB. Alterations in BBB integrity play a key role in multiple brain pathologies, including neurological (e.g. epilepsy) and neurodegenerative disorders (e.g. Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis etc.). In this review, the principal Ca2+ signaling pathways in brain microvascular endothelial cells are discussed and their contribution to BBB integrity is emphasized. Improving the knowledge of Ca2+ homeostasis alterations in BMVECa is fundamental to identify new possible drug targets that diminish/prevent BBB permeabilization in neurological and neurodegenerative disorders.
Collapse
|
10
|
Rojas S, Basualto E, Valdivia L, Vallejos N, Ceballos K, Peña E, Rivas C, Nualart F, Guzmán-Gutiérrez E, Escudero C, Toledo F, Sobrevia L, Cid M, González M. The activity of IKCa and BKCa channels contributes to insulin-mediated NO synthesis and vascular tone regulation in human umbilical vein. Nitric Oxide 2020; 99:7-16. [PMID: 32165314 DOI: 10.1016/j.niox.2020.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/23/2020] [Accepted: 03/03/2020] [Indexed: 01/16/2023]
Abstract
Insulin regulates the l-arginine/nitric oxide (NO) pathway in human umbilical vein endothelial cells (HUVECs), increasing the plasma membrane expression of the l-arginine transporter hCAT-1 and inducing vasodilation in umbilical and placental veins. Placental vascular relaxation induced by insulin is dependent of large conductance calcium-activated potassium channels (BKCa), but the role of KCa channels on l-arginine transport and NO synthesis is still unknown. The aim of this study was to determine the contribution of KCa channels in both insulin-induced l-arginine transport and NO synthesis, and its relationship with placental vascular relaxation. HUVECs, human placental vein endothelial cells (HPVECs) and placental veins were freshly isolated from umbilical cords and placenta from normal pregnancies. Cells or tissue were incubated in absence or presence of insulin and/or tetraethylammonium, 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole, iberiotoxin or NG-nitro-l-arginine methyl ester. l-Arginine uptake, plasma membrane polarity, NO levels, hCAT-1 expression and placenta vascular reactivity were analyzed. The inhibition of intermediate-conductance KCa (IKCa) and BKCa increases l-arginine uptake, which was related with protein abundance of hCAT-1 in HUVECs. IKCa and BKCa activities contribute to NO-synthesis induced by insulin but are not directly involved in insulin-stimulated l-arginine uptake. Long term incubation (8 h) with insulin increases the plasma membrane hyperpolarization and hCAT-1 expression in HUVECs and HPVECs. Insulin-induced relaxation in placental vasculature was reversed by KCa inhibition. The results show that the activity of IKCa and BKCa channels are relevant for both physiological regulations of NO synthesis and vascular tone regulation in the human placenta, acting as a part of negative feedback mechanism for autoregulation of l-arginine transport in HUVECs.
Collapse
Affiliation(s)
- Susana Rojas
- Laboratorio de Fisiología Vascular, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad deConcepción, Concepción, Chile
| | - Emerita Basualto
- Laboratorio de Fisiología Vascular, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad deConcepción, Concepción, Chile
| | - Luz Valdivia
- Laboratorio de Fisiología Vascular, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad deConcepción, Concepción, Chile
| | - Natalia Vallejos
- Laboratorio de Fisiología Vascular, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad deConcepción, Concepción, Chile; Laboratorio de Investigación Materno-Fetal (LIMaF), Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de Concepción, Concepción, Chile
| | - Karen Ceballos
- Laboratorio de Investigación Materno-Fetal (LIMaF), Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de Concepción, Concepción, Chile
| | - Eduardo Peña
- Departmento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Coralia Rivas
- Departmento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Francisco Nualart
- Departamento de Biología Celular, Laboratorio de Neurobiología y Células Madres Neuro-CellTT, Centro de Microscopía Avanzada CMA BIOBIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Enrique Guzmán-Gutiérrez
- Departamento de Bioquímica Clínica e Inmunología, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS), Chillán, Chile
| | - Carlos Escudero
- Group of Research and Innovation in Vascular Health (GRIVAS), Chillán, Chile; Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Department of Basic Sciences, Universidad del Bío-Bío, Chillán, Chile
| | - Fernando Toledo
- Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán, Chile; Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston QLD, Queensland, Australia
| | - Marcela Cid
- Departmento de Obstetricia y Puericultura, Facultad de Medicina, Universidad de Concepción, Concepción, Chile
| | - Marcelo González
- Laboratorio de Fisiología Vascular, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad deConcepción, Concepción, Chile; Laboratorio de Investigación Materno-Fetal (LIMaF), Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de Concepción, Concepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS), Chillán, Chile.
| |
Collapse
|
11
|
Sun WT, Hou HT, Chen HX, Xue HM, Wang J, He GW, Yang Q. Calcium-activated potassium channel family in coronary artery bypass grafts. J Thorac Cardiovasc Surg 2019; 161:e399-e409. [PMID: 31928817 DOI: 10.1016/j.jtcvs.2019.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 11/06/2019] [Accepted: 11/08/2019] [Indexed: 01/18/2023]
Abstract
OBJECTIVES We examined the expression, distribution, and contribution to vasodilatation of the calcium-activated potassium (KCa) channel family in the commonly used coronary artery bypass graft internal thoracic artery (ITA) and saphenous vein (SV) to understand the role of large conductance KCa (BKCa), intermediate-conductance KCa (IKCa), and small-conductance KCa (SKCa) channel subtypes in graft dilating properties determined by endothelium-smooth muscle interaction that is essential to the postoperative performance of the graft. METHODS Real-time polymerase chain reaction and western blot were employed to detect the messenger RNA and protein level of KCa channel subtypes. Distribution of KCa channel subtypes was examined by immunohistochemistry. KCa subtype-mediated vasorelaxation was studied using wire myography. RESULTS Both ITA and SV express all KCa channel subtypes with each subtype distributed in both endothelium and smooth muscle. ITA and SV do not differ in the overall expression level of each KCa channel subtype, corresponding to comparable relaxant responses to respective subtype activators. In ITA, BKCa is more abundantly expressed in smooth muscle than in endothelium, whereas SKCa exhibits more abundance in the endothelium. In comparison, SV shows even distribution of KCa channel subtypes in the 2 layers. The BKCa subtype in the KCa family plays a significant role in vasodilatation of ITA, whereas its contribution in SV is quite limited. CONCLUSIONS KCa family is abundantly expressed in ITA and SV. There are differences between these 2 grafts in the abundance of KCa channel subtypes in the endothelium and the smooth muscle. The significance of the BKCa subtype in vasodilatation of ITA may suggest the potential of development of BKCa modulators for the prevention and treatment of ITA spasm during/after coronary artery bypass graft surgery.
Collapse
Affiliation(s)
- Wen-Tao Sun
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Hai-Tao Hou
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Huan-Xin Chen
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Hong-Mei Xue
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Jun Wang
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Guo-Wei He
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; School of Pharmacy, Wannan Medical College, Wuhu, Anhui, China; Department of Surgery, Oregon Health and Science University, Portland, Ore
| | - Qin Yang
- Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China.
| |
Collapse
|
12
|
Staehr C, Hangaard L, Bouzinova EV, Kim S, Rajanathan R, Boegh Jessen P, Luque N, Xie Z, Lykke-Hartmann K, Sandow SL, Aalkjaer C, Matchkov VV. Smooth muscle Ca 2+ sensitization causes hypercontractility of middle cerebral arteries in mice bearing the familial hemiplegic migraine type 2 associated mutation. J Cereb Blood Flow Metab 2019; 39. [PMID: 29513112 PMCID: PMC6681533 DOI: 10.1177/0271678x18761712] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Familial hemiplegic migraine type 2 (FHM2) is associated with inherited point-mutations in the Na,K-ATPase α2 isoform, including G301R mutation. We hypothesized that this mutation affects specific aspects of vascular function, and thus compared cerebral and systemic arteries from heterozygote mice bearing the G301R mutation (Atp1a2+/-G301R) with wild type (WT). Middle cerebral (MCA) and mesenteric small artery (MSA) function was compared in an isometric myograph. Cerebral blood flow was assessed with Laser speckle analysis. Intracellular Ca2+ and membrane potential were measured simultaneously. Protein expression was semi-quantified by immunohistochemistry. Protein phosphorylation was analysed by Western blot. MSA from Atp1a2+/-G301R and WT showed similar contractile responses. The Atp1a2+/-G301R MCA constricted stronger to U46619, endothelin and potassium compared to WT. This was associated with an increased depolarization, although the Ca2+ change was smaller than in WT. The enhanced constriction of Atp1a2+/-G301R MCA was associated with increased cSrc activation, stronger sensitization to [Ca2+]i and increased MYPT1 phosphorylation. These differences were abolished by cSrc inhibition. Atp1a2+/-G301R mice had reduced resting blood flow through MCA in comparison with WT mice. FHM2-associated mutation leads to elevated contractility of MCA due to sensitization of the contractile machinery to Ca2+, which is mediated via Na,K-ATPase/Src-kinase/MYPT1 signalling.
Collapse
Affiliation(s)
| | - Lise Hangaard
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Sukhan Kim
- 1 Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Nathan Luque
- 2 Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia
| | - Zijian Xie
- 3 Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, WV, USA
| | | | - Shaun L Sandow
- 2 Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia
| | | | | |
Collapse
|
13
|
Agonist-evoked endothelial Ca 2+ signalling microdomains. Curr Opin Pharmacol 2019; 45:8-15. [PMID: 30986569 DOI: 10.1016/j.coph.2019.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/03/2019] [Accepted: 03/15/2019] [Indexed: 01/14/2023]
Abstract
Localized, oscillating Ca2+ signals have been identified in discrete microdomains of vascular endothelial cells. At myoendothelial contacts (between endothelial and smooth muscle cells), both endothelial Ca2+ pulsars (IP3-mediated release of intracellular Ca2+) and Ca2+ sparklets (extracellular Ca2+ entry via TRP channels) contribute to endothelium-dependent hyperpolarization of smooth muscle, vasodilation, and feedback control of vasoconstriction. Ca2+ sparklets occurring at close-contact domains between endothelial cells are possibly involved in conducted hyperpolarization and spreading vasodilation in arterial networks. This review summarizes these Ca2+ signalling phenomena, examines the proposed mechanisms leading to their generation by G-protein-coupled receptor agonists, and explores the proposed physiological roles of these localized and specialized Ca2+ signals.
Collapse
|
14
|
Hakim MA, Behringer EJ. Simultaneous Measurements of Intracellular Calcium and Membrane Potential in Freshly Isolated and Intact Mouse Cerebral Endothelium. J Vis Exp 2019. [PMID: 30735188 DOI: 10.3791/58832] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cerebral arteries and their respective microcirculation deliver oxygen and nutrients to the brain via blood flow regulation. Endothelial cells line the lumen of blood vessels and command changes in vascular diameter as needed to meet the metabolic demand of neurons. Primary endothelial-dependent signaling pathways of hyperpolarization of membrane potential (Vm) and nitric oxide typically operate in parallel to mediate vasodilation and thereby increase blood flow. Although integral to coordinating vasodilation over several millimeters of vascular length, components of endothelium-derived hyperpolarization (EDH) have been historically difficult to measure. These components of EDH entail intracellular Ca2+ [Ca2+]i increases and subsequent activation of small- and intermediate conductance Ca2+-activated K+ (SKCa/IKCa) channels. Here, we present a simplified illustration of the isolation of fresh endothelium from mouse cerebral arteries; simultaneous measurements of endothelial [Ca2+]i and Vm using Fura-2 photometry and intracellular sharp electrodes, respectively; and a continuous superfusion of salt solutions and pharmacological agents under physiological conditions (pH 7.4, 37 °C). Posterior cerebral arteries from the Circle of Willis are removed free of the posterior communicating and the basilar arteries. Enzymatic digestion of cleaned posterior cerebral arterial segments and subsequent trituration facilitates removal of adventitia, perivascular nerves, and smooth muscle cells. Resulting posterior cerebral arterial endothelial "tubes" are then secured under a microscope and examined using a camera, photomultiplier tube, and one to two electrometers while under continuous superfusion. Collectively, this method can simultaneously measure changes in endothelial [Ca2+]i and Vm in discrete cellular locations, in addition to the spreading of EDH through gap junctions up to millimeter distances along the intact endothelium. This method is expected to yield a high-throughput analysis of the cerebral endothelial functions underlying mechanisms of blood flow regulation in the normal and diseased brain.
Collapse
Affiliation(s)
- Md A Hakim
- Department of Basic Sciences, Loma Linda University
| | | |
Collapse
|
15
|
Kapela A, Behringer EJ, Segal SS, Tsoukias NM. Biophysical properties of microvascular endothelium: Requirements for initiating and conducting electrical signals. Microcirculation 2018; 25. [PMID: 29117630 DOI: 10.1111/micc.12429] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 11/02/2017] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Electrical signaling along the endothelium underlies spreading vasodilation and blood flow control. We use mathematical modeling to determine the electrical properties of the endothelium and gain insight into the biophysical determinants of electrical conduction. METHODS Electrical conduction data along endothelial tubes (40 μm wide, 2.5 mm long) isolated from mouse skeletal muscle resistance arteries were analyzed using cable equations and a multicellular computational model. RESULTS Responses to intracellular current injection attenuate with an axial length constant (λ) of 1.2-1.4 mm. Data were fitted to estimate the axial (ra ; 10.7 MΩ/mm) and membrane (rm ; 14.5 MΩ∙mm) resistivities, EC membrane resistance (Rm ; 12 GΩ), and EC-EC coupling resistance (Rgj ; 4.5 MΩ) and predict that stimulation of ≥30 neighboring ECs is required to elicit 1 mV of hyperpolarization at distance = 2.5 mm. Opening Ca2+ -activated K+ channels (KCa ) along the endothelium reduced λ by up to 55%. CONCLUSIONS High Rm makes the endothelium sensitive to electrical stimuli and able to conduct these signals effectively. Whereas the activation of a group of ECs is required to initiate physiologically relevant hyperpolarization, this requirement is increased by myoendothelial coupling and KCa activation along the endothelium inhibits conduction by dissipating electrical signals.
Collapse
Affiliation(s)
- Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Erik J Behringer
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.,Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA.,School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| |
Collapse
|
16
|
Norton CE, Segal SS. Calcitonin gene-related peptide hyperpolarizes mouse pulmonary artery endothelial tubes through K ATP channel activation. Am J Physiol Lung Cell Mol Physiol 2018. [PMID: 29543503 DOI: 10.1152/ajplung.00044.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The sensory neurotransmitter calcitonin gene-related peptide (CGRP) is associated with vasodilation of systemic arteries through activation of ATP-sensitive K+ (KATP) channels in smooth muscle cells (SMCs); however, its effects on endothelial cell (EC) membrane potential ( Vm) are unresolved. In pulmonary arteries (PAs) of C57BL/6J mice, we questioned whether CGRP would hyperpolarize ECs as well as SMCs. Intact PAs were isolated and immunostained for CGRP to confirm sensory innervation; vessel segments (1-2 mm long, ∼150 µm diameter) with intact or denuded endothelium were cannulated and pressurized to 16 cmH2O at 37°C. Increasing concentrations (10-10-10-6 M) of CGRP progressively dilated PAs preconstricted with UTP (10-5 M); SMCs hyperpolarized similarly (Δ Vm ∼20 mV) before and after endothelial denudation. To study native intact PA ECs, SMCs were dissociated to isolate endothelial tubes, and their integrity was confirmed by vital dye uptake, nuclear staining, and reproducible electrical and intracellular Ca2+ responses to acetylcholine (10-5 M) over 2 h. Increasing [CGRP] hyperpolarized ECs in a manner similar to SMCs, with each cell layer demonstrating robust immunostaining for CGRP receptor proteins. Increasing concentrations (10-10-10-6 M) of pinacidil, a KATP channel agonist, resulted in progressive hyperpolarization of SMCs of intact PAs (Δ Vm ∼30 mV), which was blocked by glibenclamide (10-6 M), as was hyperpolarization of ECs and SMCs to CGRP. Inhibition of protein kinase A with protein kinase inhibitor (10-5 M) also inhibited hyperpolarization to CGRP. We demonstrate [CGRP]-dependent hyperpolarization of ECs for the first time while validating freshly isolated PA endothelial tubes as an experimental model. Redundant electrical signaling to CGRP in ECs and SMCs implies an integral role for KATP channels in PA dilation.
Collapse
Affiliation(s)
- Charles E Norton
- Department of Medical Pharmacology and Physiology, University of Missouri , Columbia, Missouri
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center , Columbia, Missouri
| |
Collapse
|
17
|
Jackson WF. Boosting the signal: Endothelial inward rectifier K + channels. Microcirculation 2018; 24. [PMID: 27652592 DOI: 10.1111/micc.12319] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/12/2016] [Indexed: 12/19/2022]
Abstract
Endothelial cells express a diverse array of ion channels including members of the strong inward rectifier family composed of KIR 2 subunits. These two-membrane spanning domain channels are modulated by their lipid environment, and exist in macromolecular signaling complexes with receptors, protein kinases and other ion channels. Inward rectifier K+ channel (KIR ) currents display a region of negative slope conductance at membrane potentials positive to the K+ equilibrium potential that allows outward current through the channels to be activated by membrane hyperpolarization, permitting KIR to amplify hyperpolarization induced by other K+ channels and ion transporters. Increases in extracellular K+ concentration activate KIR allowing them to sense extracellular K+ concentration and transduce this change into membrane hyperpolarization. These properties position KIR to participate in the mechanism of action of hyperpolarizing vasodilators and contribute to cell-cell conduction of hyperpolarization along the wall of microvessels. The expression of KIR in capillaries in electrically active tissues may allow KIR to sense extracellular K+ , contributing to functional hyperemia. Understanding the regulation of expression and function of microvascular endothelial KIR will improve our understanding of the control of blood flow in the microcirculation in health and disease and may provide new targets for the development of therapeutics in the future.
Collapse
Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
18
|
Behringer EJ. Calcium and electrical signaling in arterial endothelial tubes: New insights into cellular physiology and cardiovascular function. Microcirculation 2018; 24. [PMID: 27801542 DOI: 10.1111/micc.12328] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/25/2016] [Indexed: 12/23/2022]
Abstract
The integral role of the endothelium during the coordination of blood flow throughout vascular resistance networks has been recognized for several decades now. Early examination of the distinct anatomy and physiology of the endothelium as a signaling conduit along the vascular wall has prompted development and application of an intact endothelial "tube" study model isolated from rodent skeletal muscle resistance arteries. Vasodilatory signals such as increased endothelial cell (EC) Ca2+ ([Ca2+ ]i ) and hyperpolarization take place in single ECs while shared between electrically coupled ECs through gap junctions up to distances of millimeters (≥2 mm). The small- and intermediate-conductance Ca2+ activated K+ (SKCa /IKCa or KCa 2.3/KCa 3.1) channels function at the interface of Ca2+ signaling and hyperpolarization; a bidirectional relationship whereby increases in [Ca2+ ]i activate SKCa /IKCa channels to produce hyperpolarization and vice versa. Further, the spatial domain of hyperpolarization among electrically coupled ECs can be finely tuned via incremental modulation of SKCa /IKCa channels to balance the strength of local and conducted electrical signals underlying vasomotor activity. Multifunctional properties of the voltage-insensitive SKCa /IKCa channels of resistance artery endothelium may be employed for therapy during the aging process and development of vascular disease.
Collapse
Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA
| |
Collapse
|
19
|
Bondarenko AI, Panasiuk O, Drachuk K, Montecucco F, Brandt KJ, Mach F. The quest for endothelial atypical cannabinoid receptor: BK Ca channels act as cellular sensors for cannabinoids in in vitro and in situ endothelial cells. Vascul Pharmacol 2018; 102:44-55. [PMID: 29355732 PMCID: PMC6481560 DOI: 10.1016/j.vph.2018.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022]
Abstract
Endothelium-dependent component of cannabinoid-induced vasodilation has been postulated to require G-protein-coupled non-CB1/CB2 endothelial cannabinoid (eCB) receptor. GPR18 was proposed as a candidate for eCBR. To address the hypothesis that the effects attributed to eCBR are mediated by G-protein-coupled receptor (GPCR)-independent targets, we studied the electrical responses in endothelial cells, focusing on BKCa channels. In patches excised from endothelial-derived EA.hy926 cells, N-arachidonoyl glycine (NAGly) and abnormal cannabidiol (abn-cbd), prototypical agonists for eCB receptor, stimulate single BKCa activity in a concentration- and Ca2+-dependent manner. The postulated eCB receptor inhibitors rimonabant and AM251 were found to inhibit basal and stimulated by NAGly- and abn-cbd BKCa activity in cell-free patches. In isolated mice aortas, abn-cbd and NAGly produced endothelial cell hyperpolarization that was sensitive to paxilline, a selective BKCa inhibitor, but not to GPR18 antibody, and mimicked by NS1619, a direct BKCa opener. In excised patches from mice aortic endothelium, single channel activity with characteristics similar to BKCa was established by the addition of abn-cbd and NAGly. We conclude that the two cannabinoids abn-cbd and NAGly initiate a GPR18-independent activation of BKCa channels in mice aortic endothelial cells that might contribute to vasodilation to cannabinoids.
Collapse
Affiliation(s)
- Alexander I Bondarenko
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine; Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz, 8010, Austria.
| | - Olga Panasiuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine
| | - Konstantin Drachuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology NAS of Ukraine, Bogomoletz Str 4, Kiev 01024, Ukraine
| | - Fabrizio Montecucco
- First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, largo Benzi 10, 16132 Genoa, Italy; Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 9 viale Benedetto XV, 16132 Genoa, Italy
| | - Karim J Brandt
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH 1211, Geneva 4, Switzerland
| | - François Mach
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH 1211, Geneva 4, Switzerland
| |
Collapse
|
20
|
Bondarenko AI, Panasiuk O, Okhai I, Montecucco F, Brandt KJ, Mach F. Ca 2+-dependent potassium channels and cannabinoid signaling in the endothelium of apolipoprotein E knockout mice before plaque formation. J Mol Cell Cardiol 2018; 115:54-63. [PMID: 29305938 DOI: 10.1016/j.yjmcc.2018.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 12/30/2017] [Accepted: 01/02/2018] [Indexed: 01/06/2023]
Abstract
Endothelial Ca2+-dependent K+ channels (KCa) regulate endothelial function. We also know that stimulation of type 2 cannabinoid (CB2) receptors ameliorates atherosclerosis. However, whether atherosclerosis is accompanied by altered endothelial KCa- and CB2 receptor-dependent signaling is unknown. By utilizing an in situ patch-clamp approach, we directly evaluated the KCa channel function and the CB2 receptor-dependent electrical responses in the endothelium of aortic strips from young ApoE-/- and C57Bl/6 mice. In the ApoE-/- group, the resting membrane potential (-30.1±1.1mV) was less negative (p<0.05) compared to WT (-38.9±1.4mV) and voltage ramps generated an overall KCa current of reduced amplitude. The peak hyperpolarization to 2μM Ach was not different between the groups. However, the sustained component was significantly reduced in ApoE-/- strips. In contrast, the peak hyperpolarization to 0.2μM Ach was increased in the ApoE-/- group, and SKA-31, a direct IKCa/SKCa channel opener, produced a hyperpolarization and whole-cell current of greater amplitude. The BKCa opener NS1619 produced hyperpolarization that was enhanced in ApoE-/- group. N-arachidonoyl glycine, a BKCa opener, produced a hyperpolarization of enhanced amplitude in ApoE-/- arteries. Selective CB2 receptor agonist AM1241 (5μM) had no effect on endothelial membrane potential in WT group; however, in ApoE-/- group, it elicited hyperpolarization that was inhibited by a selective CB2 receptor antagonist AM630. Conclusively, our data point to functional down-regulation of basal IKCa activity in unstimulated endothelium of ApoE-/- mice. Direct and indirect IKCa stimulation resulted in increased recruitment of the channels. In addition, our data point to up-regulation of endothelial BKCa channels and CB2 receptors in ApoE-/- arteries.
Collapse
Affiliation(s)
- Alexander I Bondarenko
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine.
| | - Olga Panasiuk
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine
| | - Iryna Okhai
- Circulatory Physiology Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz Str.4, 01024 Kiev, Ukraine
| | - Fabrizio Montecucco
- First Clinic of Internal Medicine, Department of Internal Medicine, University of Genoa, 6 viale Benedetto XV, 16132 Genoa, Italy; Ospedale Policlinico San Martino, largo Benzi 10, 16132 Genoa, Italy; Centre of Excellence for Biomedical Research (CEBR), University of Genoa, 9 viale Benedetto XV, 16132 Genoa, Italy
| | - Karim J Brandt
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH -1211 Geneva, 4, Switzerland
| | - François Mach
- Division of Cardiology, Foundation for Medical Researches, Department of Internal Medicine, University of Geneva, Av. de la Roseraie 64, CH -1211 Geneva, 4, Switzerland
| |
Collapse
|
21
|
Naik JS, Walker BR. Endothelial-dependent dilation following chronic hypoxia involves TRPV4-mediated activation of endothelial BK channels. Pflugers Arch 2018; 470:633-648. [PMID: 29380056 PMCID: PMC5854740 DOI: 10.1007/s00424-018-2112-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 12/23/2022]
Abstract
Following chronic hypoxia (CH), the systemic vasculature exhibits blunted vasoconstriction due to endothelial-dependent hyperpolarization (EDH). Previous data demonstrate that subsequent to CH, EDH-mediated vasodilation switches from a reliance on SKca and IKca channels to activation of the endothelial BKca channels (eBK). The mechanism by which endothelial cell stimulation activates eBK channels following CH is not known. We hypothesized that following CH, EDH-dependent vasodilation involves a TRPV4-dependent activation of eBK channels. ACh induced concentration-dependent dilation in pressurized gracilis arteries from both normoxic and CH rats. Inhibition of TRPV4 (RN-1734) attenuated the ACh response in arteries from CH rats but had no effect in normoxic animals. In the presence of L-NNA and indomethacin, TRPV4 blockade attenuated ACh-induced vasodilation in arteries from CH rats. ACh elicited endothelial TRPV4-mediated Ca2+ events in arteries from both groups. GSK1016790A (GSK101, TRPV4 agonist) elicited vasodilation in arteries from normoxic and CH rats. In arteries from normoxic animals, TRAM-34/apamin abolished the dilation to TRPV4 activation, whereas luminal iberiotoxin had no effect. In CH rats, only administration of all three Kca channel inhibitors abolished the dilation to TRPV4 activation. Using Duolink®, we observed co-localization between Cav-1, TRPV4, and BK channels in gracilis arteries and in RAECs. Disruption of endothelial caveolae with methyl-β-cyclodextrin significantly decreased ACh-induced vasodilation in arteries from both groups. In gracilis arteries, endothelial membrane cholesterol was significantly decreased following 48 h of CH. In conclusion, CH results in a functional coupling between muscarinic receptors, TRPV4 and Kca channels in gracilis arteries.
Collapse
Affiliation(s)
- Jay S Naik
- Department of Cell Biology and Physiology, University of New Mexico, MSC08 4750, Albuquerque, NM, 87131, USA.
| | - Benjimen R Walker
- Department of Cell Biology and Physiology, University of New Mexico, MSC08 4750, Albuquerque, NM, 87131, USA
| |
Collapse
|
22
|
Goto K, Ohtsubo T, Kitazono T. Endothelium-Dependent Hyperpolarization (EDH) in Hypertension: The Role of Endothelial Ion Channels. Int J Mol Sci 2018; 19:E315. [PMID: 29361737 PMCID: PMC5796258 DOI: 10.3390/ijms19010315] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 12/28/2022] Open
Abstract
Upon stimulation with agonists and shear stress, the vascular endothelium of different vessels selectively releases several vasodilator factors such as nitric oxide and prostacyclin. In addition, vascular endothelial cells of many vessels regulate the contractility of the vascular smooth muscle cells through the generation of endothelium-dependent hyperpolarization (EDH). There is a general consensus that the opening of small- and intermediate-conductance Ca2+-activated K⁺ channels (SKCa and IKCa) is the initial mechanistic step for the generation of EDH. In animal models and humans, EDH and EDH-mediated relaxations are impaired during hypertension, and anti-hypertensive treatments restore such impairments. However, the underlying mechanisms of reduced EDH and its improvement by lowering blood pressure are poorly understood. Emerging evidence suggests that alterations of endothelial ion channels such as SKCa channels, inward rectifier K⁺ channels, Ca2+-activated Cl- channels, and transient receptor potential vanilloid type 4 channels contribute to the impaired EDH during hypertension. In this review, we attempt to summarize the accumulating evidence regarding the pathophysiological role of endothelial ion channels, focusing on their relationship with EDH during hypertension.
Collapse
Affiliation(s)
- Kenichi Goto
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Toshio Ohtsubo
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
| |
Collapse
|
23
|
Behringer EJ, Segal SS. Impact of Aging on Calcium Signaling and Membrane Potential in Endothelium of Resistance Arteries: A Role for Mitochondria. J Gerontol A Biol Sci Med Sci 2017; 72:1627-1637. [PMID: 28510636 DOI: 10.1093/gerona/glx079] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/21/2017] [Indexed: 12/20/2022] Open
Abstract
Impaired blood flow to peripheral tissues during advanced age is associated with endothelial dysfunction and diminished bioavailability of nitric oxide (NO). However, it is unknown whether aging impacts coupling between intracellular calcium ([Ca2+]i) signaling and small- and intermediate K+ channel (SKCa/IKCa) activity during endothelium-derived hyperpolarization (EDH), a signaling pathway integral to dilation of the resistance vasculature. To address the potential impact of aging on EDH, Fura-2 photometry and intracellular recording were applied to evaluate [Ca2+]i and membrane potential of intact endothelial tubes (width, 60 µm; length, 1-3 mm) freshly isolated from superior epigastric arteries of young (4-6 mo) and old (24-26 mo) male C57BL/6 mice. In response to acetylcholine, intracellular release of Ca2+ from the endoplasmic reticulum (ER) was enhanced with aging. Further, treatment with the mitochondrial uncoupler FCCP evoked a significant increase of [Ca2+]i with membrane hyperpolarization in an SKCa/IKCa-dependent manner in the endothelium of old but not young mice. We conclude that the ability of resistance artery endothelium to release Ca2+ from intracellular stores (ie, ER and mitochondria) and hyperpolarize Vm via SKCa/IKCa activation is augmented as compensation for reduced NO bioavailability during advanced age.
Collapse
Affiliation(s)
- Erik J Behringer
- Department of Basic Sciences, Loma Linda University, California.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia.,Dalton Cardiovascular Research Center, Columbia, Missouri
| |
Collapse
|
24
|
Khaddaj Mallat R, Mathew John C, Kendrick DJ, Braun AP. The vascular endothelium: A regulator of arterial tone and interface for the immune system. Crit Rev Clin Lab Sci 2017; 54:458-470. [PMID: 29084470 DOI: 10.1080/10408363.2017.1394267] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As the primary interface between the blood and various tissues of the body, the vascular endothelium exhibits a diverse range of roles and activities, all of which contribute to the overall health and function of the cardiovascular system. In this focused review, we discuss several key aspects of endothelial function, how this may be compromised and subsequent consequences. Specifically, we examine the dynamic regulation of arterial contractility and distribution of blood flow through the generation of chemical and electrical signaling events that impinge upon vascular smooth muscle. The endothelium can generate a diverse range of vasoactive compounds and signals, most of which act locally to adjust blood flow in a dynamic fashion to match tissue metabolism. Disruption of these vascular signaling processes (e.g. reduced nitric oxide bioavailability) is typically referred to as endothelial dysfunction, which is a recognized risk factor for cardiovascular disease in patients and occurs early in the development and progression of hypertension, atherosclerosis and tissue ischemia. Endothelial dysfunction is also associated with type-2 Diabetes and aging and increased mechanistic knowledge of the cellular changes contributing to these effects may provide important clues for interventional strategies. The endothelium also serves as the initial site of interaction for immune cells entering tissues in response to damage and acts to facilitate the actions of both the innate and acquired immune systems to interact with the vascular wall. In addition to representing the main cell type responsible for the formation of new blood vessels (i.e. angiogenesis) within the vasculature, the endothelium is also emerging as a source of extracellular vesicle or microparticles for the transport of signaling molecules and other cellular materials to nearby, or remote, sites in the body. The characteristics of released microparticles appear to change with the functional status of the endothelium; thus, these microparticles may represent novel biomarkers of endothelial health and more serious cardiovascular disease.
Collapse
Affiliation(s)
- Rayan Khaddaj Mallat
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Cini Mathew John
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Dylan J Kendrick
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| | - Andrew P Braun
- a Department of Physiology and Pharmacology, Cumming School of Medicine , University of Calgary, and Libin Cardiovascular Institute of Alberta , Calgary , Canada
| |
Collapse
|
25
|
Dai H, Wang M, Patel PN, Kalogeris T, Liu Y, Durante W, Korthuis RJ. Preconditioning with the BK Ca channel activator NS-1619 prevents ischemia-reperfusion-induced inflammation and mucosal barrier dysfunction: roles for ROS and heme oxygenase-1. Am J Physiol Heart Circ Physiol 2017; 313:H988-H999. [PMID: 28822969 DOI: 10.1152/ajpheart.00620.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 07/25/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022]
Abstract
Activation of large-conductance Ca2+-activated K+ (BKCa) channels evokes cell survival programs that mitigate intestinal ischemia and reperfusion (I/R) inflammation and injury 24 h later. The goal of the present study was to determine the roles of reactive oxygen species (ROS) and heme oxygenase (HO)-1 in delayed acquisition of tolerance to I/R induced by pretreatment with the BKCa channel opener NS-1619. Superior mesentery arteries were occluded for 45 min followed by reperfusion for 70 min in wild-type (WT) or HO-1-null (HO-1-/-) mice that were pretreated with NS-1619 or saline vehicle 24 h earlier. Intravital microscopy was used to quantify the numbers of rolling and adherent leukocytes. Mucosal permeability, tumor necrosis factor-α (TNF-α) levels, and HO-1 activity and expression in jejunum were also determined. I/R induced leukocyte rolling and adhesion, increased intestinal TNF-α levels, and enhanced mucosal permeability in WT mice, effects that were largely abolished by pretreatment with NS-1619. The anti-inflammatory and mucosal permeability-sparing effects of NS-1619 were prevented by coincident treatment with the HO-1 inhibitor tin protoporphyrin-IX or a cell-permeant SOD mimetic, Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), in WT mice. NS-1619 also increased jejunal HO-1 activity in WT animals, an effect that was attenuated by treatment with the BKCa channel antagonist paxilline or MnTBAP. I/R also increased postischemic leukocyte rolling and adhesion and intestinal TNF-α levels in HO-1-/- mice to levels comparable to those noted in WT animals. However, NS-1619 was ineffective in preventing these effects in HO-1-deficient mice. In summary, our data indicate that NS-1619 induces the development of an anti-inflammatory phenotype and mitigates postischemic mucosal barrier disruption in the small intestine by a mechanism that may involve ROS-dependent HO-1 activity.NEW & NOTEWORTHY Antecedent treatment with the large-conductance Ca2+-activated K+ channel opener NS-1619 24 h before ischemia-reperfusion limits postischemic tissue injury by an oxidant-dependent mechanism. The present study shows that NS-1619-induced oxidant production prevents ischemia-reperfusion-induced inflammation and mucosal barrier disruption in the small intestine by provoking increases in heme oxygenase-1 activity.
Collapse
Affiliation(s)
- Hongyan Dai
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Meifang Wang
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Parag N Patel
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Theodore Kalogeris
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Yajun Liu
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - William Durante
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| | - Ronald J Korthuis
- Department of Medical Pharmacology and Physiology and Dalton Cardiovascular Research Center, University of Missouri School of Medicine, Columbia, Missouri
| |
Collapse
|
26
|
Transient receptor potential canonical type 3 channels: Interactions, role and relevance - A vascular focus. Pharmacol Ther 2017; 174:79-96. [DOI: 10.1016/j.pharmthera.2017.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
27
|
Ruamyod K, Watanapa WB, Shayakul C. Testosterone rapidly increases Ca 2+-activated K + currents causing hyperpolarization in human coronary artery endothelial cells. J Steroid Biochem Mol Biol 2017; 168:118-126. [PMID: 28223151 DOI: 10.1016/j.jsbmb.2017.02.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 12/20/2022]
Abstract
Testosterone has endothelium-dependent vasodilatory effects on the coronary artery, with some reports suggesting endothelial ion channel involvement. This study employed the whole-cell patch clamp technique to investigate the effect of testosterone on ion channels in human coronary artery endothelial cells (HCAECs) and the mechanisms involved. We found that 0.03-3μM testosterone significantly induced a rapid, concentration-dependent increase in total HCAEC current (EC50, 71.96±1.66nM; maximum increase, 59.13±8.37%; mean±SEM). The testosterone-enhanced currents consisted of small- and large-conductance Ca2+-activated K+ currents (SKCa and BKCa currents), but not Cl- and nonselective cation currents. Either a non-permeant testosterone conjugate or the non-aromatizable androgen dihydrotestosterone (DHT) could increase HCAEC currents as well. The androgen receptor antagonist flutamide prevented this testosterone, testosterone conjugate, and DHT effect, while the estrogen receptor antagonist fulvestrant did not. Incubating HCAECs with pertussis toxin or protein kinase A inhibitor H-89 largely inhibited the testosterone effect, while pre-incubation with phospholipase C inhibitor U-73122, prostacyclin inhibitor indomethacin, nitric oxide synthase inhibitor L-NAME or cytochrome P450 inhibitor MS-PPOH, did not. Finally, testosterone application induced HCAEC hyperpolarization within minutes; this effect was prevented by SKCa and BKCa current inhibitors apamin and iberiotoxin. This is the first electrophysiological demonstration of androgen-induced KCa current increase, leading to hyperpolarization, in any endothelial cell, and the first report of SKCa as a testosterone target. Our data show that testosterone rapidly increased whole-cell HCAEC SKCa and BKCa currents via a surface androgen receptor, Gi/o protein, and protein kinase A. This mechanism may explain rapid testosterone-induced coronary vasodilation seen in vivo.
Collapse
Affiliation(s)
- Katesirin Ruamyod
- Department of Physiology Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
| | - Wattana B Watanapa
- Department of Physiology Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
| | - Chairat Shayakul
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
| |
Collapse
|
28
|
Al Suleimani YM, Al Mahruqi AS. The endogenous lipid N-arachidonoyl glycine is hypotensive and nitric oxide-cGMP-dependent vasorelaxant. Eur J Pharmacol 2016; 794:209-215. [PMID: 27890711 DOI: 10.1016/j.ejphar.2016.11.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/13/2016] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
Abstract
N-arachidonoyl glycine (NAGLY), is the endogenous lipid that activates the G protein-couple receptor 18 (GPR18) with vasodilatory activity in resistance arteries. This study investigates its hemodynamic effects and mechanisms of vasorelaxation. Hemodynamic effects of NAGLY in rats were assessed using a Biopac system and its vascular responses were assessed using a wire myograph. NAGLY (1mg/kg) decreased blood pressure by 69.4±5.5% and reduced renal blood flow by 88±12% and the effects were not sensitive to inhibition by O-1918 (3mg/kg). In resistant vessels, NAGLY (1-30µM) induced concentration- and endothelium-dependent vasorelaxation and the effect was inhibited by the nitric oxide synthase inhibitor, L-NAME (300µM), a cGMP synthase inhibitor, ODQ (10µM), the antagonists of "endothelial anandamide" receptor, rimonabant (3µM) and O-1918 (10µM) and the inhibitor of Na+/Ca2+ exchanger (NCX), KB-R7943 (10µM). On the other hand, NAGLY-induced vasorelaxation was not affected by CID 16020046 (GPR55 antagonist), AM 251 (cannabinoid CB1 receptor antagonist), AM 630 (cannabinoid CB2 receptor antagonist), capsazepine (TRPV1 antagonist), indomethacin (cyclooxygenase inhibitor), TRAM34 (IKCa channel blocker), iberiotoxin (BKCa channel blocker) and GW9662 (PPARɤ antagonist). At low concentrations of carbachol, NAGLY potentiated carbachol-induced vasorelaxation. NAGLY is an endothelium-dependent vasodilator and hypotensive lipid. The vasorelaxation is predominantly via activation of nitric oxide-cGMP pathway and NCX and probably mediated by the "endothelial anandamide" receptor, while the hypotensive effect of NAGLY appears not to involve the anandamide receptor. NAGLY also potentiates carbachol-induced vasorelaxation, the mechanism of which might involve stimulation of NO release.
Collapse
Affiliation(s)
- Yousuf M Al Suleimani
- Department of Pharmacology and Clinical Pharmacy, College of Medicine and Health Sciences, Sultan Qaboos University, 35, Alkoudh 123, Sultanate of Oman.
| | - Ahmed S Al Mahruqi
- Department of Pharmacology and Clinical Pharmacy, College of Medicine and Health Sciences, Sultan Qaboos University, 35, Alkoudh 123, Sultanate of Oman
| |
Collapse
|
29
|
Cabrera L, Saavedra A, Rojas S, Cid M, Valenzuela C, Gallegos D, Careaga P, Basualto E, Haensgen A, Peña E, Rivas C, Vera JC, Gallardo V, Zúñiga L, Escudero C, Sobrevia L, Wareing M, González M. Insulin Induces Relaxation and Decreases Hydrogen Peroxide-Induced Vasoconstriction in Human Placental Vascular Bed in a Mechanism Mediated by Calcium-Activated Potassium Channels and L-Arginine/Nitric Oxide Pathways. Front Physiol 2016; 7:529. [PMID: 27920724 PMCID: PMC5118463 DOI: 10.3389/fphys.2016.00529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 10/25/2016] [Indexed: 01/04/2023] Open
Abstract
HIGHLIGHTSShort-term incubation with insulin increases the L-arginine transport in HUVECs. Short-term incubation with insulin increases the NO synthesis in HUVECs. Insulin induces relaxation in human placental vascular bed. Insulin attenuates the constriction induced by hydrogen peroxide in human placenta. The relaxation induced by insulin is dependent on BKCa channels activity in human placenta.
Insulin induces relaxation in umbilical veins, increasing the expression of human amino acid transporter 1 (hCAT-1) and nitric oxide synthesis (NO) in human umbilical vein endothelial cells (HUVECs). Short-term effects of insulin on vasculature have been reported in healthy subjects and cell cultures; however, its mechanisms remain unknown. The aim of this study was to characterize the effect of acute incubation with insulin on the regulation of vascular tone of placental vasculature. HUVECs and chorionic vein rings were isolated from normal pregnancies. The effect of insulin on NO synthesis, L-arginine transport, and hCAT-1 abundance was measured in HUVECs. Isometric tension induced by U46619 (thromboxane A2 analog) or hydrogen peroxide (H2O2) were measured in vessels previously incubated 30 min with insulin and/or the following pharmacological inhibitors: tetraethylammonium (KCa channels), iberiotoxin (BKCa channels), genistein (tyrosine kinases), and wortmannin (phosphatidylinositol 3-kinase). Insulin increases L-arginine transport and NO synthesis in HUVECs. In the placenta, this hormone caused relaxation of the chorionic vein, and reduced perfusion pressure in placental cotyledons. In vessels pre-incubated with insulin, the constriction evoked by H2O2 and U46619 was attenuated and the effect on H2O2-induced constriction was blocked with tetraethylammonium and iberiotoxin, but not with genistein, or wortmannin. Insulin rapidly dilates the placental vasculature through a mechanism involving activity of BKCa channels and L-arginine/NO pathway in endothelial cells. This phenomenon is related to quick increases of hCAT-1 abundance and higher capacity of endothelial cells to take up L-arginine and generate NO.
Collapse
Affiliation(s)
- Lissette Cabrera
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Department of Morphophysiology, Faculty of Medicine, Universidad Diego PortalesSantiago, Chile
| | - Andrea Saavedra
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Susana Rojas
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Marcela Cid
- Department of Obstetrics and Childcare, Faculty of Medicine, Universidad de Concepción Concepción, Chile
| | - Cristina Valenzuela
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - David Gallegos
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Pamela Careaga
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Emerita Basualto
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Astrid Haensgen
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Eduardo Peña
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Coralia Rivas
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Juan Carlos Vera
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de Concepción Concepción, Chile
| | - Victoria Gallardo
- Department of Pathophysiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas (CIM), School of Medicine, Universidad de Talca Talca, Chile
| | - Carlos Escudero
- Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile; Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Department of Basic Sciences, Universidad del BiobíoChillán, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de ChileSantiago, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de SevillaSeville, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of QueenslandHerston, QLD, Australia
| | - Mark Wareing
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of ManchesterManchester, UK; Maternal and Fetal Health Research Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science CentreManchester, UK
| | - Marcelo González
- Vascular Physiology Laboratory, Department of Physiology, Faculty of Biological Sciences, Universidad de ConcepciónConcepción, Chile; Group of Research and Innovation in Vascular Health (GRIVAS Health)Chillán, Chile
| |
Collapse
|
30
|
Vascular structural and functional changes: their association with causality in hypertension: models, remodeling and relevance. Hypertens Res 2016; 40:311-323. [PMID: 27784889 DOI: 10.1038/hr.2016.145] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022]
Abstract
Essential hypertension is a complex multifactorial disease process that involves the interaction of multiple genes at various loci throughout the genome, and the influence of environmental factors such as diet and lifestyle, to ultimately determine long-term arterial pressure. These factors converge with physiological signaling pathways to regulate the set-point of long-term blood pressure. In hypertension, structural changes in arteries occur and show differences within and between vascular beds, between species, models and sexes. Such changes can also reflect the development of hypertension, and the levels of circulating humoral and vasoactive compounds. The role of perivascular adipose tissue in the modulation of vascular structure under various disease states such as hypertension, obesity and metabolic syndrome is an emerging area of research, and is likely to contribute to the heterogeneity described in this review. Diversity in structure and related function is the norm, with morphological changes being causative in some beds and states, and in others, a consequence of hypertension. Specific animal models of hypertension have advantages and limitations, each with factors influencing the relevance of the model to the human hypertensive state/s. However, understanding the fundamental properties of artery function and how these relate to signalling mechanisms in real (intact) tissues is key for translating isolated cell and model data to have an impact and relevance in human disease etiology. Indeed, the ultimate aim of developing new treatments to correct vascular dysfunction requires understanding and recognition of the limitations of the methodologies used.
Collapse
|
31
|
Ellinsworth DC, Sandow SL, Shukla N, Liu Y, Jeremy JY, Gutterman DD. Endothelium-Derived Hyperpolarization and Coronary Vasodilation: Diverse and Integrated Roles of Epoxyeicosatrienoic Acids, Hydrogen Peroxide, and Gap Junctions. Microcirculation 2016; 23:15-32. [PMID: 26541094 DOI: 10.1111/micc.12255] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/01/2015] [Indexed: 12/22/2022]
Abstract
Myocardial perfusion and coronary vascular resistance are regulated by signaling metabolites released from the local myocardium that act either directly on the VSMC or indirectly via stimulation of the endothelium. A prominent mechanism of vasodilation is EDH of the arteriolar smooth muscle, with EETs and H(2)O(2) playing important roles in EDH in the coronary microcirculation. In some cases, EETs and H(2)O(2) are released as transferable hyperpolarizing factors (EDHFs) that act directly on the VSMCs. By contrast, EETs and H(2)O(2) can also promote endothelial KCa activity secondary to the amplification of extracellular Ca(2+) influx and Ca(2+) mobilization from intracellular stores, respectively. The resulting endothelial hyperpolarization may subsequently conduct to the media via myoendothelial gap junctions or potentially lead to the release of a chemically distinct factor(s). Furthermore, in human isolated coronary arterioles dilator signaling involving EETs and H(2)O(2) may be integrated, being either complimentary or inhibitory depending on the stimulus. With an emphasis on the human coronary microcirculation, this review addresses the diverse and integrated mechanisms by which EETs and H(2)O(2) regulate vessel tone and also examines the hypothesis that myoendothelial microdomain signaling facilitates EDH activity in the human heart.
Collapse
Affiliation(s)
| | - Shaun L Sandow
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Nilima Shukla
- Bristol Heart Institute, University of Bristol, Bristol, UK
| | - Yanping Liu
- Division of Research Infrastructure, National Center for Research Resources, National Institutes of Health, Bethesda, Maryland, USA
| | - Jamie Y Jeremy
- Bristol Heart Institute, University of Bristol, Bristol, UK
| | - David D Gutterman
- Division of Cardiovascular Medicine, Departments of Medicine, Physiology and Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| |
Collapse
|
32
|
Naik JS, Osmond JM, Walker BR, Kanagy NL. Hydrogen sulfide-induced vasodilation mediated by endothelial TRPV4 channels. Am J Physiol Heart Circ Physiol 2016; 311:H1437-H1444. [PMID: 27765747 DOI: 10.1152/ajpheart.00465.2016] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/30/2016] [Indexed: 01/03/2023]
Abstract
Hydrogen sulfide (H2S) is a recently described gaseous vasodilator produced within the vasculature by the enzymes cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase. Previous data demonstrate that endothelial cells (EC) are the source of endogenous H2S production and are required for H2S-induced dilation. However, the signal transduction pathway activated by H2S within EC has not been elucidated. TRPV4 and large-conductance Ca2+-activated K channels (BK channels) are expressed in EC. H2S-induced dilation is inhibited by luminal administration of iberiotoxin and disruption of the endothelium. Calcium influx through TRPV4 may activate these endothelial BK channels (eBK). We hypothesized that H2S-mediated vasodilation involves activation of TRPV4 within the endothelium. In pressurized, phenylephrine-constricted mesenteric arteries, H2S elicited a dose-dependent vasodilation blocked by inhibition of TRPV4 channels (GSK2193874A, 300 nM). H2S (1 μM) increased TRPV4-dependent (1.8-fold) localized calcium events in EC of pressurized arteries loaded with fluo-4 and Oregon Green. In pressurized EC tubes, H2S (1 μM) and the TRPV4 activator, GSK101679A (30 nM), increased calcium events 1.8- and 1.5-fold, respectively. H2S-induced an iberiotoxin-sensitive outward current measured using whole cell patch-clamp techniques in freshly dispersed EC. H2S increased K+ currents from 10 to 30 pA/pF at +150 mV. Treatment with Na2S increased the level of sulfhydration of TRPV4 channels in aortic ECs. These results demonstrate that H2S-mediated vasodilation involves activation of TRPV4-dependent Ca2+ influx and BK channel activation within EC. Activation of TRPV4 channels appears to cause calcium events that result in the opening of eBK channels, endothelial hyperpolarization, and subsequent vasodilation.
Collapse
Affiliation(s)
- Jay S Naik
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico
| | - Jessica M Osmond
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico
| | - Benjimen R Walker
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico
| | - Nancy L Kanagy
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico
| |
Collapse
|
33
|
Choi S, Kim JA, Li H, Shin K, Oh GT, Lee Y, Oh S, Pewzner‐Jung Y, Futerman AH, Suh SH. KCa 3.1 upregulation preserves endothelium-dependent vasorelaxation during aging and oxidative stress. Aging Cell 2016; 15:801-10. [PMID: 27363720 PMCID: PMC5013018 DOI: 10.1111/acel.12502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 01/24/2023] Open
Abstract
Endothelial oxidative stress develops with aging and reactive oxygen species impair endothelium-dependent relaxation (EDR) by decreasing nitric oxide (NO) availability. Endothelial KCa 3.1, which contributes to EDR, is upregulated by H2 O2 . We investigated whether KCa 3.1 upregulation compensates for diminished EDR to NO during aging-related oxidative stress. Previous studies identified that the levels of ceramide synthase 5 (CerS5), sphingosine, and sphingosine 1-phosphate were increased in aged wild-type and CerS2 mice. In primary mouse aortic endothelial cells (MAECs) from aged wild-type and CerS2 null mice, superoxide dismutase (SOD) was upregulated, and catalase and glutathione peroxidase 1 (GPX1) were downregulated, when compared to MAECs from young and age-matched wild-type mice. Increased H2 O2 levels induced Fyn and extracellular signal-regulated kinases (ERKs) phosphorylation and KCa 3.1 upregulation. Catalase/GPX1 double knockout (catalase(-/-) /GPX1(-/-) ) upregulated KCa 3.1 in MAECs. NO production was decreased in aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) MAECs. However, KCa 3.1 activation-induced, N(G) -nitro-l-arginine-, and indomethacin-resistant EDR was increased without a change in acetylcholine-induced EDR in aortic rings from aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) mice. CerS5 transfection or exogenous application of sphingosine or sphingosine 1-phosphate induced similar changes in levels of the antioxidant enzymes and upregulated KCa 3.1. Our findings suggest that, during aging-related oxidative stress, SOD upregulation and downregulation of catalase and GPX1, which occur upon altering the sphingolipid composition or acyl chain length, generate H2 O2 and thereby upregulate KCa 3.1 expression and function via a H2 O2 /Fyn-mediated pathway. Altogether, enhanced KCa 3.1 activity may compensate for decreased NO signaling during vascular aging.
Collapse
Affiliation(s)
- Shinkyu Choi
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Ji Aee Kim
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Hai‐yan Li
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Kyong‐Oh Shin
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Goo Taeg Oh
- Department of Life Sciences Ewha Womans University Seoul South Korea
| | - Yong‐Moon Lee
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Seikwan Oh
- Department of Molecular Medicine Medical School Ewha Womans University Seoul South Korea
| | - Yael Pewzner‐Jung
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Anthony H. Futerman
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Suk Hyo Suh
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| |
Collapse
|
34
|
Hei H, Gao J, Dong J, Tao J, Tian L, Pan W, Wang H, Zhang X. BK Knockout by TALEN-Mediated Gene Targeting in Osteoblasts: KCNMA1 Determines the Proliferation and Differentiation of Osteoblasts. Mol Cells 2016; 39:530-5. [PMID: 27329042 PMCID: PMC4959017 DOI: 10.14348/molcells.2016.0033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 11/27/2022] Open
Abstract
Large conductance calcium-activated potassium (BK) channels participate in many important physiological functions in excitable tissues such as neurons, cardiac and smooth muscles, whereas the knowledge of BK channels in bone tissues and osteoblasts remains elusive. To investigate the role of BK channels in osteoblasts, we used transcription activator-like effector nuclease (TALEN) to establish a BK knockout cell line on rat ROS17/2.8 osteoblast, and detected the proliferation and mineralization of the BK-knockout cells. Our study found that the BK-knockout cells significantly decreased the ability of proliferation and mineralization as osteoblasts, compared to the wild type cells. The overall expression of osteoblast differentiation marker genes in the BK-knockout cells was significantly lower than that in wild type osteoblast cells. The BK-knockout osteoblast cell line in our study displays a phenotype decrease in osteoblast function which can mimic the pathological state of osteoblast and thus provide a working cell line as a tool for study of osteoblast function and bone related diseases.
Collapse
Affiliation(s)
- Hongya Hei
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Jianjun Gao
- Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai, 200032,
China
| | - Jibin Dong
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Jie Tao
- Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062,
China
| | - Lulu Tian
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Wanma Pan
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| | - Hongyu Wang
- Department of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016,
China
| | - Xuemei Zhang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203,
China
| |
Collapse
|
35
|
Calcium-Activated Potassium Channels: Potential Target for Cardiovascular Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:233-261. [PMID: 27038376 DOI: 10.1016/bs.apcsb.2015.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ca(2+)-activated K(+) channels (KCa) are classified into three subtypes: big conductance (BKCa), intermediate conductance (IKCa), and small conductance (SKCa) KCa channels. The three types of KCa channels have distinct physiological or pathological functions in cardiovascular system. BKCa channels are mainly expressed in vascular smooth muscle cells (VSMCs) and inner mitochondrial membrane of cardiomyocytes, activation of BKCa channels in these locations results in vasodilation and cardioprotection against cardiac ischemia. IKCa channels are expressed in VSMCs, endothelial cells, and cardiac fibroblasts and involved in vascular smooth muscle proliferation, migration, vessel dilation, and cardiac fibrosis. SKCa channels are widely expressed in nervous and cardiovascular system, and activation of SKCa channels mainly contributes membrane hyperpolarization. In this chapter, we summarize the physiological and pathological roles of the three types of KCa channels in cardiovascular system and put forward the possibility of KCa channels as potential target for cardiovascular diseases.
Collapse
|
36
|
Behringer EJ, Segal SS. Membrane potential governs calcium influx into microvascular endothelium: integral role for muscarinic receptor activation. J Physiol 2015; 593:4531-48. [PMID: 26260126 DOI: 10.1113/jp271102] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/03/2015] [Indexed: 01/12/2023] Open
Abstract
In resistance arteries, coupling a rise of intracellular calcium concentration ([Ca(2+)]i) to endothelial cell hyperpolarization underlies smooth muscle cell relaxation and vasodilatation, thereby increasing tissue blood flow and oxygen delivery. A controversy persists as to whether changes in membrane potential (V(m)) alter endothelial cell [Ca(2+)]i. We tested the hypothesis that V(m) governs [Ca(2+)]i in endothelium of resistance arteries by performing Fura-2 photometry while recording and controlling V(m) of intact endothelial tubes freshly isolated from superior epigastric arteries of C57BL/6 mice. Under resting conditions, [Ca(2+)]i did not change when V(m) shifted from baseline (∼-40 mV) via exposure to 10 μM NS309 (hyperpolarization to ∼-80 mV), via equilibration with 145 mm [K(+)]o (depolarization to ∼-5 mV), or during intracellular current injection (±0.5 to 5 nA, 20 s pulses) while V(m) changed linearly between ∼-80 mV and +10 mV. In contrast, during the plateau (i.e. Ca(2+) influx) phase of the [Ca(2+)]i response to approximately half-maximal stimulation with 100 nm ACh (∼EC50), [Ca(2+)]i increased as V(m) hyperpolarized below -40 mV and decreased as V(m) depolarized above -40 mV. The magnitude of [Ca(2+)]i reduction during depolarizing current injections correlated with the amplitude of the plateau [Ca(2+)]i response to ACh. The effect of hyperpolarization on [Ca(2+)]i was abolished following removal of extracellular Ca(2+), was enhanced subtly by raising extracellular [Ca(2+)] from 2 mm to 10 mm and was reduced by half in endothelium of TRPV4(-/-) mice. Thus, during submaximal activation of muscarinic receptors, V(m) can modulate Ca(2+) entry through the plasma membrane in accord with the electrochemical driving force.
Collapse
Affiliation(s)
- Erik J Behringer
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA.,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA
| |
Collapse
|
37
|
Gokina NI, Bonev AD, Phillips J, Gokin AP, Veilleux K, Oppenheimer K, Goloman G. Impairment of IKCa channels contributes to uteroplacental endothelial dysfunction in rat diabetic pregnancy. Am J Physiol Heart Circ Physiol 2015; 309:H592-604. [PMID: 26092991 DOI: 10.1152/ajpheart.00901.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 06/19/2015] [Indexed: 12/18/2022]
Abstract
Diabetes in rat pregnancy is associated with impaired vasodilation of the maternal uteroplacental vasculature. In the present study, we explored the role of endothelial cell (EC) Ca(2+)-activated K(+) channels of small conductance (SKCa channels) and intermediate conductance (IKCa channels) in diabetes-induced uterine vascular dysfunction. Diabetes was induced by injection of streptozotocin to second-day pregnant rats and confirmed by the development of maternal hyperglycemia. Control rats were injected with citrate buffer. Changes in smooth muscle cell intracellular Ca(2+) concentration, membrane potential, and vasodilation induced by SKCa/IKCa channel activators were studied in uteroplacental arteries of control and diabetic rats. The impact of diabetes on SKCa- and IKCa-mediated currents was explored in freshly dissociated ECs. NS309 evoked a potent vasodilation that was effectively inhibited by TRAM-34 but not by apamin. NS309-induced smooth muscle cell intracellular Ca(2+) concentration, membrane potential, and dilator responses were significantly diminished by diabetes; N-cyclohexyl-N-2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-4-pyrimidinamine (CyPPA)-evoked responses were not affected. Ca(2+)-activated ion currents in ECs were insensitive to paxilline, markedly inhibited by charybdotoxin (ChTX), and diminished by apamin. NS309-induced EC currents were generated mostly due to activation of ChTX-sensitive channels. Maternal diabetes resulted in a significant reduction in ChTX-sensitive currents with no effect on apamin-sensitive or CyPPA-induced currents. We concluded that IKCa channels play a prevalent role over SKCa channels in the generation of endothelial K(+) currents and vasodilation of uteroplacental arteries. Impaired function of IKCa channels importantly contributes to diabetes-induced uterine endothelial dysfunction. Therapeutic restoration of IKCa channel function may be a novel strategy for improvement of maternal uteroplacental blood flow in pregnancies complicated by diabetes.
Collapse
Affiliation(s)
- Natalia I Gokina
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Adrian D Bonev
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, Vermont
| | - Julie Phillips
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Alexander P Gokin
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Kelsey Veilleux
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Karen Oppenheimer
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| | - Gabriela Goloman
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Vermont, Burlington, Vermont; and
| |
Collapse
|
38
|
Al-Brakati AY, Kamishima T, Dart C, Quayle JM. Caveolar disruption causes contraction of rat femoral arteries via reduced basal NO release and subsequent closure of BKCa channels. PeerJ 2015; 3:e966. [PMID: 26038721 PMCID: PMC4451037 DOI: 10.7717/peerj.966] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/29/2015] [Indexed: 12/22/2022] Open
Abstract
Background and Purpose. Caveolae act as signalling hubs in endothelial and smooth muscle cells. Caveolar disruption by the membrane cholesterol depleting agent methyl-β-cyclodextrin (M-β-CD) has various functional effects on arteries including (i) impairment of endothelium-dependent relaxation, and (ii) alteration of smooth muscle cell (SMC) contraction independently of the endothelium. The aim of this study was to explore the effects of M-β-CD on rat femoral arteries. Methods. Isometric force was measured in rat femoral arteries stimulated to contract with a solution containing 20 mM K(+) and 200 nM Bay K 8644 (20 K/Bay K) or with one containing 80 mM K(+)(80 K). Results. Incubation of arteries with M-β-CD (5 mM, 60 min) increased force in response to 20 K/Bay K but not that induced by 80 K. Application of cholesterol saturated M-β-CD (Ch-MCD, 5 mM, 50 min) reversed the effects of M-β-CD. After mechanical removal of endothelial cells M-β-CD caused only a small enhancement of contractions to 20 K/Bay K. This result suggests M-β-CD acts via altering release of an endothelial-derived vasodilator or vasoconstrictor. When nitric oxide synthase was blocked by pre-incubation of arteries with L-NAME (250 µM) the contraction of arteries to 20 K/Bay K was enhanced, and this effect was abolished by pre-treatment with M-β-CD. This suggests M-β-CD is inhibiting endothelial NO release. Inhibition of large conductance voltage- and Ca(2+)-activated (BKCa) channels with 2 mM TEA(+) or 100 nM Iberiotoxin (IbTX) enhanced 20 K/Bay K contractions. L-NAME attenuated the contractile effect of IbTX, as did endothelial removal. Conclusions. Our results suggest caveolar disruption results in decreased release of endothelial-derived nitric oxide in rat femoral artery, resulting in a reduced contribution of BKCa channels to the smooth muscle cell membrane potential, causing depolarisation and contraction.
Collapse
Affiliation(s)
- AY Al-Brakati
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - T Kamishima
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - C Dart
- Department of Biochemistry and Cell Biology, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - JM Quayle
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| |
Collapse
|
39
|
Bondarenko AI. Endothelial atypical cannabinoid receptor: do we have enough evidence? Br J Pharmacol 2014; 171:5573-88. [PMID: 25073723 PMCID: PMC4290703 DOI: 10.1111/bph.12866] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 07/14/2014] [Accepted: 07/24/2014] [Indexed: 12/16/2022] Open
Abstract
Cannabinoids and their synthetic analogues affect a broad range of physiological functions, including cardiovascular variables. Although direct evidence is still missing, the relaxation of a vast range of vascular beds induced by cannabinoids is believed to involve a still unidentified non-CB1 , non-CB2 Gi/o protein-coupled receptor located on endothelial cells, the so called endothelial cannabinoid receptor (eCB receptor). Evidence for the presence of an eCB receptor comes mainly from vascular relaxation studies, which commonly employ pertussis toxin as an indicator for GPCR-mediated signalling. In addition, a pharmacological approach is widely used to attribute the relaxation to eCB receptors. Recent findings have indicated a number of GPCR-independent targets for both agonists and antagonists of the presumed eCB receptor, warranting further investigations and cautious interpretation of the vascular relaxation studies. This review will provide a brief historical overview on the proposed novel eCB receptor, drawing attention to the discrepancies between the studies on the pharmacological profile of the eCB receptor and highlighting the Gi/o protein-independent actions of the eCB receptor inhibitors widely used as selective compounds. As the eCB receptor represents an attractive pharmacological target for a number of cardiovascular abnormalities, defining its molecular identity and the extent of its regulation of vascular function will have important implications for drug discovery. This review highlights the need to re-evaluate this subject in a thoughtful and rigorous fashion. More studies are needed to differentiate Gi/o protein-dependent endothelial cannabinoid signalling from that involving the classical CB1 and CB2 receptors as well as its relevance for pathophysiological conditions.
Collapse
Affiliation(s)
- Alexander I Bondarenko
- Circulatory Physiology Department, O.O.Bogomoletz Institute of PhysiologyKiev, Ukraine
- Institute of Molecular Biology and Biochemistry, Medical University of GrazGraz, Austria
| |
Collapse
|
40
|
Bondarenko AI, Drachuk K, Panasiuk O, Sagach V, Deak AT, Malli R, Graier WF. N-Arachidonoyl glycine suppresses Na⁺/Ca²⁺ exchanger-mediated Ca²⁺ entry into endothelial cells and activates BK(Ca) channels independently of GPCRs. Br J Pharmacol 2014; 169:933-48. [PMID: 23517055 PMCID: PMC3687672 DOI: 10.1111/bph.12180] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/14/2013] [Accepted: 02/20/2013] [Indexed: 02/03/2023] Open
Abstract
Background and Purpose N-arachidonoyl glycine (NAGly) is a lipoamino acid with vasorelaxant properties. We aimed to explore the mechanisms of NAGly's action on unstimulated and agonist-stimulated endothelial cells. Experimental Approach The effects of NAGly on endothelial electrical signalling were studied in combination with vascular reactivity. Key Results In EA.hy926 cells, the sustained hyperpolarization to histamine was inhibited by the non-selective Na+/Ca2+ exchanger (NCX) inhibitor bepridil and by an inhibitor of reversed mode NCX, KB-R7943. In cells dialysed with Cs+-based Na+-containing solution, the outwardly rectifying current with typical characteristics of NCX was augmented following histamine exposure, further increased upon external Na+ withdrawal and inhibited by bepridil. NAGly (0.3–30 μM) suppressed NCX currents in a URB597- and guanosine 5′-O-(2-thiodiphosphate) (GDPβS)-insensitive manner, [Ca2+]i elevation evoked by Na+ removal and the hyperpolarization to histamine. In rat aorta, NAGly opposed the endothelial hyperpolarization and relaxation response to ACh. In unstimulated EA.hy926 cells, NAGly potentiated the whole-cell current attributable to large-conductance Ca2+-activated K+ (BKCa) channels in a GDPβS-insensitive, paxilline-sensitive manner and produced a sustained hyperpolarization. In cell-free inside-out patches, NAGly stimulated single BKCa channel activity. Conclusion and Implications Our data showed that NCX is a Ca2+ entry pathway in endothelial cells and that NAGly is a potent G-protein-independent modulator of endothelial electrical signalling and has a dual effect on endothelial electrical responses. In agonist pre-stimulated cells, NAGly opposes hyperpolarization and relaxation via inhibition of NCX-mediated Ca2+ entry, while in unstimulated cells, it promotes hyperpolarization via receptor-independent activation of BKCa channels.
Collapse
Affiliation(s)
- Alexander I Bondarenko
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria.
| | | | | | | | | | | | | |
Collapse
|
41
|
Ginsenoside Re enhances small-conductance Ca(2+)-activated K(+) current in human coronary artery endothelial cells. Life Sci 2014; 115:15-21. [PMID: 25242515 DOI: 10.1016/j.lfs.2014.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 08/23/2014] [Accepted: 09/09/2014] [Indexed: 01/26/2023]
Abstract
AIMS Ginsenosides, active components in ginseng, have been shown to increase nitric oxide (NO) production in aortic endothelial cells. This effect was reversed by tetraethylammonium (TEA) inhibition of endothelial Ca(2+)-activated K(+) (KCa) channels. The objectives of this study, therefore, were to test 1) whether vasorelaxing ginsenoside Re could affect KCa current, an important regulator of NO production, in human coronary artery endothelial cells (HCAECs); and 2) whether small-conductance KCa (SKCa) channel was the channel subtype involved. MAIN METHODS Ionic currents of cultured HCAECs were studied using whole-cell patch clamp technique. KEY FINDINGS Ginsenoside Re dose-dependently increased endothelial outward currents, with an EC50 of 408.90±1.59nM, and a maximum increase of 36.20±5.62% (mean±SEM; p<0.05). Apamin, an SKCa channel inhibitor, could block this effect, while La(3+), a nonselective cation channel (NSC) blocker, could not. When NSC channel, inward-rectifier K(+) channel, intermediate-, and large-conductance KCa channels were simultaneously blocked, ginsenoside Re could still increase outward currents significantly (35.49±4.22%; p<0.05); this effect was again abolished by apamin. Repeating the experiments when Cl(-) channel was additionally blocked gave similar results. Finally, we demonstrated that ginsenoside Re could hyperpolarize HCAECs; this effect was reversed by apamin. These data clearly indicate that ginsenoside Re increased HCAEC outward current via SKCa channel activation, and NSC channel was not involved. SIGNIFICANCE This is the first report to demonstrate that ginsenoside Re could increase SKCa channel activity in HCAECs. This can be a mechanism mediating ginseng's beneficial actions on coronary vessels.
Collapse
|
42
|
P2Y(12) receptor on the verge of a neuroinflammatory breakdown. Mediators Inflamm 2014; 2014:975849. [PMID: 25180027 PMCID: PMC4142314 DOI: 10.1155/2014/975849] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/25/2014] [Accepted: 06/26/2014] [Indexed: 12/22/2022] Open
Abstract
In the CNS, neuroinflammation occurring during pathologies as amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) is the consequence of an intricate interplay orchestrated by various cell phenotypes. Among the molecular cues having a role in this process, extracellular nucleotides are responsible for intercellular communication and propagation of inflammatory stimuli. This occurs by binding to several receptor subtypes, defined P2X/P2Y, which are widespread in different tissues and simultaneously localized on multiple cells. For instance, the metabotropic P2Y12 subtype is found in the CNS on microglia, affecting activation and chemotaxis, on oligodendrocytes, possessing a hypothesized role in myelination, and on astrocytes. By comparative analysis, we have established here that P2Y12 receptor immunolabelled by antibodies against C-terminus or second intracellular loop, is, respectively, distributed and modulated under neuroinflammatory conditions on ramified microglia or myelinated fibers, in primary organotypic cerebellar cultures, tissue slices from rat striatum and cerebellum, spinal cord sections from symptomatic/end stage SOD1-G93A ALS mice, and finally autoptic cortical tissue from progressive MS donors. We suggest that modulation of P2Y12 expression might play a dual role as analytic marker of branched/surveillant microglia and demyelinating lesions, thus potentially acquiring a predictive value under neuroinflammatory conditions as those found in ALS and MS.
Collapse
|
43
|
Petkov GV. Central role of the BK channel in urinary bladder smooth muscle physiology and pathophysiology. Am J Physiol Regul Integr Comp Physiol 2014; 307:R571-84. [PMID: 24990859 DOI: 10.1152/ajpregu.00142.2014] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The physiological functions of the urinary bladder are to store and periodically expel urine. These tasks are facilitated by the contraction and relaxation of the urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, which comprises the bladder wall. The large-conductance voltage- and Ca(2+)-activated K(+) (BK, BKCa, MaxiK, Slo1, or KCa1.1) channel is highly expressed in UBSM and is arguably the most important physiologically relevant K(+) channel that regulates UBSM function. Its significance arises from the fact that the BK channel is the only K(+) channel that is activated by increases in both voltage and intracellular Ca(2+). The BK channels control UBSM excitability and contractility by maintaining the resting membrane potential and shaping the repolarization phase of the spontaneous action potentials that determine UBSM spontaneous rhythmic contractility. In UBSM, these channels have complex regulatory mechanisms involving integrated intracellular Ca(2+) signals, protein kinases, phosphodiesterases, and close functional interactions with muscarinic and β-adrenergic receptors. BK channel dysfunction is implicated in some forms of bladder pathologies, such as detrusor overactivity, and related overactive bladder. This review article summarizes the current state of knowledge of the functional role of UBSM BK channels under normal and pathophysiological conditions and provides new insight toward the BK channels as targets for pharmacological or genetic control of UBSM function. Modulation of UBSM BK channels can occur by directly or indirectly targeting their regulatory mechanisms, which has the potential to provide novel therapeutic approaches for bladder dysfunction, such as overactive bladder and detrusor underactivity.
Collapse
Affiliation(s)
- Georgi V Petkov
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
| |
Collapse
|
44
|
Large conductance Ca2+-activated K+ channel (BKCa) α-subunit splice variants in resistance arteries from rat cerebral and skeletal muscle vasculature. PLoS One 2014; 9:e98863. [PMID: 24921651 PMCID: PMC4055454 DOI: 10.1371/journal.pone.0098863] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/07/2014] [Indexed: 11/19/2022] Open
Abstract
Previous studies report functional differences in large conductance Ca2+ activated-K+ channels (BKCa) of smooth muscle cells (VSMC) from rat cerebral and cremaster muscle resistance arteries. The present studies aimed to determine if this complexity in BKCa activity may, in part, be due to splice variants in the pore-forming α-subunit. BKCa variants in the intracellular C terminus of the α-subunit, and their relative expression to total α-subunit, were examined by qPCR. Sequencing of RT-PCR products showed two α-subunit variants, ZERO and STREX, to be identical in cremaster and cerebral arteries. Levels of STREX mRNA expression were, however, significantly higher in cremaster VSMCs (28.9±4.2% of total α-BKCa) compared with cerebral vessels (16.5±0.9%). Further, a low level of BKCa SS4 α-subunit variant was seen in cerebral arteries, while undetectable in cremaster arteries. Protein biotinylation assays, in expression systems and arterial preparations, were used to determine whether differences in splice variant mRNA expression affect surface membrane/cytosolic location of the channel. In AD-293 and CHO-K1 cells, rat STREX was more likely to be located at the plasma membrane compared to ZERO, although the great majority of channel protein was in the membrane in both cases. Co-expression of β1-BKCa subunit with STREX or ZERO did not influence the dominant membrane expression of α-BKCa subunits, whereas in the absence of α-BKCa, a significant proportion of β1-subunit remained cytosolic. Biotinylation assays of cremaster and cerebral arteries showed that differences in STREX/ZERO expression do not alter membrane/cytosolic distribution of the channel under basal conditions. These data, however, revealed that the amount of α-BKCa in cerebral arteries is approximately 20X higher than in cremaster vessels. Thus, the data support the major functional differences in BKCa activity in cremaster, as compared to cerebral VSMCs, being related to total α-BKCa expression, regardless of differences in splice variant expression.
Collapse
|
45
|
The proteome of mouse cerebral arteries. J Cereb Blood Flow Metab 2014; 34:1033-46. [PMID: 24667914 PMCID: PMC4050249 DOI: 10.1038/jcbfm.2014.52] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 12/29/2022]
Abstract
The cerebral vasculature ensures proper cerebral function by transporting oxygen, nutrients, and other substances to the brain. Distribution of oxygenated blood throughout the neuroaxis takes place at the level of the circle of Willis (CW). While morphologic and functional alterations in CW arteries and its main branches have been reported in cerebrovascular and neurodegenerative diseases, accompanying changes in protein expression profiles remain largely uncharacterized. In this study, we performed proteomics to compile a novel list of proteins present in mouse CW arteries and its ramifications. Circle of Willis arteries were surgically removed from 6-month-old wild-type mice, proteins extracted and analyzed by two proteomics approaches, gel-free nanoLC-mass spectrometry (MS)/MS and gel-based GelLC-MS/MS, using nanoAcquity UPLC coupled with ESI-LTQ Orbitrap XL. The two approaches helped maximize arterial proteome coverage. Six biologic and two technical replicates were performed. In all, 2,188 proteins with at least 2 unique high-scoring peptides were identified (6,630 proteins total). Proteins were classified according to vasoactivity, blood-brain barrier specificity, tight junction and adhesion molecules, membrane transporters/channels, and extracellular matrix/basal lamina proteins. Furthermore, we compared the identified CW arterial proteome with the published brain microvascular proteome. Our database provides a vital resource for the study of CW cerebral arterial protein expression profiles in health and disease.
Collapse
|
46
|
Revermann M, Neofitidou S, Kirschning T, Schloss M, Brandes RP, Hofstetter C. Inhalation of the BK(Ca)-opener NS1619 attenuates right ventricular pressure and improves oxygenation in the rat monocrotaline model of pulmonary hypertension. PLoS One 2014; 9:e86636. [PMID: 24497961 PMCID: PMC3909005 DOI: 10.1371/journal.pone.0086636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 12/11/2013] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Right heart failure is a fatal consequence of chronic pulmonary hypertension (PH). The development of PH is characterized by increased proliferation of vascular cells, in particular pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells. In the course of PH, an escalated right ventricular (RV) afterload occurs, which leads to increased perioperative morbidity and mortality. BK(Ca) channels are ubiquitously expressed in vascular smooth muscle cells and their opening induces cell membrane hyperpolarization followed by vasodilation. Moreover, BK activation induces anti-proliferative effects in a multitude of cell types. On this basis, we hypothesized that treatment with the nebulized BK channel opener NS1619 might be a therapy option for pulmonary hypertension and tested this in rats. METHODS (1) Rats received monocrotaline injection for PH induction. Twenty-four days later, rats were anesthetized and NS1619 or the solvent was administered by inhalation. Systemic hemodynamic parameters, RV hemodynamic parameters, and blood gas analyses were measured before as well as 30 and 120 minutes after inhalation. (2) Rat PASMCs were stimulated with PDGF-BB in the presence and absence of NS1619. AKT, ERK1 and ERK2 activation were investigated by western blot analyses, and relative cell number was determined 48 hours after stimulation. RESULTS Inhalation of a 12 µM and 100 µM NS1619 solution significantly reduced RV pressure without affecting systemic arterial pressure. Blood gas analyses demonstrated significantly reduced carbon dioxide and improved oxygenation in NS1619-treated animals pointing towards a considerable pulmonary shunt-reducing effect. In PASMC's, NS1619 (100 µM) significantly attenuated PASMC proliferation by a pathway independent of AKT and ERK1/2 activation. CONCLUSION NS1619 inhalation reduces RV pressure and improves oxygen supply and its application inhibits PASMC proliferation in vitro. Hence, BK opening might be a novel option for the treatment of pulmonary hypertension.
Collapse
MESH Headings
- Administration, Inhalation
- Animals
- Becaplermin
- Benzimidazoles/administration & dosage
- Benzimidazoles/pharmacology
- Blotting, Western
- Cell Proliferation/drug effects
- Cells, Cultured
- Hemodynamics/drug effects
- Hypertension, Pulmonary/chemically induced
- Hypertension, Pulmonary/physiopathology
- Hypertension, Pulmonary/prevention & control
- Large-Conductance Calcium-Activated Potassium Channels/metabolism
- Male
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Monocrotaline
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Oxygen/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Proto-Oncogene Proteins c-sis/pharmacology
- Pulmonary Artery/cytology
- Rats
- Rats, Sprague-Dawley
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Dysfunction, Right/prevention & control
- Ventricular Pressure/drug effects
Collapse
Affiliation(s)
- Marc Revermann
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Skevi Neofitidou
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Thomas Kirschning
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Manuel Schloss
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Ralf P. Brandes
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Christian Hofstetter
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
47
|
Ruisanchez É, Dancs P, Kerék M, Németh T, Faragó B, Balogh A, Patil R, Jennings BL, Liliom K, Malik KU, Smrcka AV, Tigyi G, Benyó Z. Lysophosphatidic acid induces vasodilation mediated by LPA1 receptors, phospholipase C, and endothelial nitric oxide synthase. FASEB J 2013; 28:880-90. [PMID: 24249637 DOI: 10.1096/fj.13-234997] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Lysophosphatidic acid (LPA) has been implicated as a mediator of several cardiovascular functions, but its potential involvement in the control of vascular tone is obscure. Here, we show that both LPA (18:1) and VPC31143 (a synthetic agonist of LPA1-3 receptors) relax intact mouse thoracic aorta with similar Emax values (53.9 and 51.9% of phenylephrine-induced precontraction), although the EC50 of LPA- and VPC31143-induced vasorelaxations were different (400 vs. 15 nM, respectively). Mechanical removal of the endothelium or genetic deletion of endothelial nitric oxide synthase (eNOS) not only diminished vasorelaxation by LPA or VPC31143 but converted it to vasoconstriction. Freshly isolated mouse aortic endothelial cells expressed LPA1, LPA2, LPA4 and LPA5 transcripts. The LPA1,3 antagonist Ki16425, the LPA1 antagonist AM095, and the genetic deletion of LPA1, but not that of LPA2, abolished LPA-induced vasorelaxation. Inhibition of the phosphoinositide 3 kinase-protein kinase B/Akt pathway by wortmannin or MK-2206 failed to influence the effect of LPA. However, pharmacological inhibition of phospholipase C (PLC) by U73122 or edelfosine, but not genetic deletion of PLCε, abolished LPA-induced vasorelaxation and indicated that a PLC enzyme, other than PLCε, mediates the response. In summary, the present study identifies LPA as an endothelium-dependent vasodilator substance acting via LPA1, PLC, and eNOS.
Collapse
Affiliation(s)
- Éva Ruisanchez
- 1Z.B., Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, POB 448, H-1446 Budapest, Hungary.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Shao Z, Friedlander M, Hurst CG, Cui Z, Pei DT, Evans LP, Juan AM, Tahir H, Duhamel F, Chen J, Sapieha P, Chemtob S, Joyal JS, Smith LEH. Choroid sprouting assay: an ex vivo model of microvascular angiogenesis. PLoS One 2013; 8:e69552. [PMID: 23922736 PMCID: PMC3724908 DOI: 10.1371/journal.pone.0069552] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/11/2013] [Indexed: 12/14/2022] Open
Abstract
Angiogenesis of the microvasculature is central to the etiology of many diseases including proliferative retinopathy, age-related macular degeneration and cancer. A mouse model of microvascular angiogenesis would be very valuable and enable access to a wide range of genetically manipulated tissues that closely approximate small blood vessel growth in vivo. Vascular endothelial cells cultured in vitro are widely used, however, isolating pure vascular murine endothelial cells is technically challenging. A microvascular mouse explant model that is robust, quantitative and can be reproduced without difficulty would overcome these limitations. Here we characterized and optimized for reproducibility an organotypic microvascular angiogenesis mouse and rat model from the choroid, a microvascular bed in the posterior of eye. The choroidal tissues from C57BL/6J and 129S6/SvEvTac mice and Sprague Dawley rats were isolated and incubated in Matrigel. Vascular sprouting was comparable between choroid samples obtained from different animals of the same genetic background. The sprouting area, normalized to controls, was highly reproducible between independent experiments. We developed a semi-automated macro in ImageJ software to allow for more efficient quantification of sprouting area. Isolated choroid explants responded to manipulation of the external environment while maintaining the local interactions of endothelial cells with neighboring cells, including pericytes and macrophages as evidenced by immunohistochemistry and fluorescence-activated cell sorting (FACS) analysis. This reproducible ex vivo angiogenesis assay can be used to evaluate angiogenic potential of pharmacologic compounds on microvessels and can take advantage of genetically manipulated mouse tissue for microvascular disease research.
Collapse
Affiliation(s)
- Zhuo Shao
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mollie Friedlander
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Christian G. Hurst
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Zhenghao Cui
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Dorothy T. Pei
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lucy P. Evans
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Aimee M. Juan
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Houda Tahir
- Departments of Pediatrics Ophthalmology and Pharmacology, Research Centers of CHU Sainte-Justine, Montreal, Quebec, Canada
| | - François Duhamel
- Department of Ophthalmology, Research Centers of Hôpital Maisonneuve-Rosemont, University of Montreal, Montreal, Quebec, Canada
- Departments of Pediatrics Ophthalmology and Pharmacology, Research Centers of CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Jing Chen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Przemyslaw Sapieha
- Department of Ophthalmology, Research Centers of Hôpital Maisonneuve-Rosemont, University of Montreal, Montreal, Quebec, Canada
| | - Sylvain Chemtob
- Department of Ophthalmology, Research Centers of Hôpital Maisonneuve-Rosemont, University of Montreal, Montreal, Quebec, Canada
- Departments of Pediatrics Ophthalmology and Pharmacology, Research Centers of CHU Sainte-Justine, Montreal, Quebec, Canada
| | - Jean-Sébastien Joyal
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lois E. H. Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
49
|
Endothelial control of vasodilation: integration of myoendothelial microdomain signalling and modulation by epoxyeicosatrienoic acids. Pflugers Arch 2013; 466:389-405. [PMID: 23748495 DOI: 10.1007/s00424-013-1303-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 05/24/2013] [Accepted: 05/26/2013] [Indexed: 12/17/2022]
Abstract
Endothelium-derived epoxyeicosatrienoic acids (EETs) are fatty acid epoxides that play an important role in the control of vascular tone in selected coronary, renal, carotid, cerebral and skeletal muscle arteries. Vasodilation due to endothelium-dependent smooth muscle hyperpolarization (EDH) has been suggested to involve EETs as a transferable endothelium-derived hyperpolarizing factor. However, this activity may also be due to EETs interacting with the components of other primary EDH-mediated vasodilator mechanisms. Indeed, the transfer of hyperpolarization initiated in the endothelium to the adjacent smooth muscle via gap junction connexins occurs separately or synergistically with the release of K(+) ions at discrete myoendothelial microdomain signalling sites. The net effects of such activity are smooth muscle hyperpolarization, closure of voltage-dependent Ca(2+) channels, phospholipase C deactivation and vasodilation. The spatially localized and key components of the microdomain signalling complex are the inositol 1,4,5-trisphosphate receptor-mediated endoplasmic reticulum Ca(2+) store, Ca(2+)-activated K(+) (KCa), transient receptor potential (TRP) and inward-rectifying K(+) channels, gap junctions and the smooth muscle Na(+)/K(+)-ATPase. Of these, TRP channels and connexins are key endothelial effector targets modulated by EETs. In an integrated manner, endogenous EETs enhance extracellular Ca(2+) influx (thereby amplifying and prolonging KCa-mediated endothelial hyperpolarization) and also facilitate the conduction of this hyperpolarization to spatially remote vessel regions. The contribution of EETs and the receptor and channel subtypes involved in EDH-related microdomain signalling, as a candidate for a universal EDH-mediated vasodilator mechanism, vary with vascular bed, species, development and disease and thus represent potentially selective targets for modulating specific artery function.
Collapse
|
50
|
Vasodilator compounds derived from plants and their mechanisms of action. Molecules 2013; 18:5814-57. [PMID: 23685938 PMCID: PMC6270466 DOI: 10.3390/molecules18055814] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 04/24/2013] [Accepted: 05/07/2013] [Indexed: 12/31/2022] Open
Abstract
The present paper reviews vasodilator compounds isolated from plants that were reported in the past 22 years (1990 to 2012) and the different mechanisms of action involved in their vasodilator effects. The search for reports was conducted in a comprehensive manner, intending to encompass those metabolites with a vasodilator effect whose mechanism of action involved both vascular endothelium and arterial smooth muscle. The results obtained from our bibliographic search showed that over half of the isolated compounds have a mechanism of action involving the endothelium. Most of these bioactive metabolites cause vasodilation either by activating the nitric oxide/cGMP pathway or by blocking voltage-dependent calcium channels. Moreover, it was found that many compounds induced vasodilation by more than one mechanism. This review confirms that secondary metabolites, which include a significant group of compounds with extensive chemical diversity, are a valuable source of new pharmaceuticals useful for the treatment and prevention of cardiovascular diseases.
Collapse
|