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Moccia F, Brunetti V, Soda T, Berra-Romani R, Scarpellino G. Cracking the Endothelial Calcium (Ca 2+) Code: A Matter of Timing and Spacing. Int J Mol Sci 2023; 24:16765. [PMID: 38069089 PMCID: PMC10706333 DOI: 10.3390/ijms242316765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/16/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
A monolayer of endothelial cells lines the innermost surface of all blood vessels, thereby coming into close contact with every region of the body and perceiving signals deriving from both the bloodstream and parenchymal tissues. An increase in intracellular Ca2+ concentration ([Ca2+]i) is the main mechanism whereby vascular endothelial cells integrate the information conveyed by local and circulating cues. Herein, we describe the dynamics and spatial distribution of endothelial Ca2+ signals to understand how an array of spatially restricted (at both the subcellular and cellular levels) Ca2+ signals is exploited by the vascular intima to fulfill this complex task. We then illustrate how local endothelial Ca2+ signals affect the most appropriate vascular function and are integrated to transmit this information to more distant sites to maintain cardiovascular homeostasis. Vasorelaxation and sprouting angiogenesis were selected as an example of functions that are finely tuned by the variable spatio-temporal profile endothelial Ca2+ signals. We further highlighted how distinct Ca2+ signatures regulate the different phases of vasculogenesis, i.e., proliferation and migration, in circulating endothelial precursors.
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Affiliation(s)
- Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
| | - Valentina Brunetti
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
| | - Teresa Soda
- Department of Health Sciences, University of Magna Graecia, 88100 Catanzaro, Italy;
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico;
| | - Giorgia Scarpellino
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
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Behringer EJ. Impact of aging on vascular ion channels: perspectives and knowledge gaps across major organ systems. Am J Physiol Heart Circ Physiol 2023; 325:H1012-H1038. [PMID: 37624095 PMCID: PMC10908410 DOI: 10.1152/ajpheart.00288.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/21/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Individuals aged ≥65 yr will comprise ∼20% of the global population by 2030. Cardiovascular disease remains the leading cause of death in the world with age-related endothelial "dysfunction" as a key risk factor. As an organ in and of itself, vascular endothelium courses throughout the mammalian body to coordinate blood flow to all other organs and tissues (e.g., brain, heart, lung, skeletal muscle, gut, kidney, skin) in accord with metabolic demand. In turn, emerging evidence demonstrates that vascular aging and its comorbidities (e.g., neurodegeneration, diabetes, hypertension, kidney disease, heart failure, and cancer) are "channelopathies" in large part. With an emphasis on distinct functional traits and common arrangements across major organs systems, the present literature review encompasses regulation of vascular ion channels that underlie blood flow control throughout the body. The regulation of myoendothelial coupling and local versus conducted signaling are discussed with new perspectives for aging and the development of chronic diseases. Although equipped with an awareness of knowledge gaps in the vascular aging field, a section has been included to encompass general feasibility, role of biological sex, and additional conceptual and experimental considerations (e.g., cell regression and proliferation, gene profile analyses). The ultimate goal is for the reader to see and understand major points of deterioration in vascular function while gaining the ability to think of potential mechanistic and therapeutic strategies to sustain organ perfusion and whole body health with aging.
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Affiliation(s)
- Erik J Behringer
- Basic Sciences, Loma Linda University, Loma Linda, California, United States
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Razan MR, Amissi S, Islam RA, Graham JL, Stanhope KL, Havel PJ, Rahimian R. Moderate-Intensity Exercise Improves Mesenteric Arterial Function in Male UC Davis Type-2 Diabetes Mellitus (UCD-T2DM) Rats: A Shift in the Relative Importance of Endothelium-Derived Relaxing Factors (EDRF). Biomedicines 2023; 11:biomedicines11041129. [PMID: 37189747 DOI: 10.3390/biomedicines11041129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/01/2023] [Accepted: 04/05/2023] [Indexed: 05/17/2023] Open
Abstract
The beneficial cardiovascular effects of exercise are well documented, however the mechanisms by which exercise improves vascular function in diabetes are not fully understood. This study investigates whether there are (1) improvements in blood pressure and endothelium-dependent vasorelaxation (EDV) and (2) alterations in the relative contribution of endothelium-derived relaxing factors (EDRF) in modulating mesenteric arterial reactivity in male UC Davis type-2 diabetes mellitus (UCD-T2DM) rats, following an 8-week moderate-intensity exercise (MIE) intervention. EDV to acetylcholine (ACh) was measured before and after exposure to pharmacological inhibitors. Contractile responses to phenylephrine and myogenic tone were determined. The arterial expressions of endothelial nitric oxide (NO) synthase (eNOS), cyclooxygenase (COX), and calcium-activated potassium channel (KCa) channels were also measured. T2DM significantly impaired EDV, increased contractile responses and myogenic tone. The impairment of EDV was accompanied by elevated NO and COX importance, whereas the contribution of prostanoid- and NO-independent (endothelium-derived hyperpolarization, EDH) relaxation was not apparent compared to controls. MIE 1) enhanced EDV, while it reduced contractile responses, myogenic tone and systolic blood pressure (SBP), and 2) caused a shift away from a reliance on COX toward a greater reliance on EDH in diabetic arteries. We provide the first evidence of the beneficial effects of MIE via the altered importance of EDRF in mesenteric arterial relaxation in male UCD-T2DM rats.
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Affiliation(s)
- Md Rahatullah Razan
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA 95211, USA
| | - Said Amissi
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA 95211, USA
| | - Rifat Ara Islam
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA 95211, USA
| | - James L Graham
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
- Department of Nutrition, University of California, Davis, CA 95616, USA
| | - Kimber L Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
- Department of Nutrition, University of California, Davis, CA 95616, USA
| | - Peter J Havel
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
- Department of Nutrition, University of California, Davis, CA 95616, USA
| | - Roshanak Rahimian
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA 95211, USA
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King DR, Sedovy MW, Eaton X, Dunaway LS, Good ME, Isakson BE, Johnstone SR. Cell-To-Cell Communication in the Resistance Vasculature. Compr Physiol 2022; 12:3833-3867. [PMID: 35959755 DOI: 10.1002/cphy.c210040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.
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Affiliation(s)
- D Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Meghan W Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, Virginia, USA
| | - Xinyan Eaton
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA
| | - Luke S Dunaway
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Miranda E Good
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Centre, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Scott R Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Vascular and Heart Research, Virginia Tech, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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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.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, United States
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Akther F, Razan MR, Shaligram S, Graham JL, Stanhope KL, Allen KN, Vázquez-Medina JP, Havel PJ, Rahimian R. Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses. Front Physiol 2021; 12:616317. [PMID: 34366875 PMCID: PMC8339592 DOI: 10.3389/fphys.2021.616317] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats.
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Affiliation(s)
- Farjana Akther
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - Md Rahatullah Razan
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - Sonali Shaligram
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - James L. Graham
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Kimber L. Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Kaitlin N. Allen
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | | | - Peter J. Havel
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Nutrition, University of California, Davis, Davis, CA, United States
| | - Roshanak Rahimian
- Department of Physiology & Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
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Chen M, Li X. Role of TRPV4 channel in vasodilation and neovascularization. Microcirculation 2021; 28:e12703. [PMID: 33971061 DOI: 10.1111/micc.12703] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/02/2021] [Indexed: 12/12/2022]
Abstract
The transient receptor potential vanilloid type 4 (TRPV4) channel, a Ca2+ -permeable nonselective cation channel, is widely distributed in the circulatory system, particularly in vascular endothelial cells (ECs) and smooth muscle cells (SMCs). The TRPV4 channel is activated by various endogenous and exogenous stimuli, including shear stress, low intravascular pressure, and arachidonic acid. TRPV4 has a role in mediating vascular tone and arterial blood pressure. The activation of the TRPV4 channel induces Ca2+ influx, thereby resulting in endothelium-dependent hyperpolarization and SMC relaxation through SKCa and IKCa activation on ECs or through BKCa activation on SMCs. Ca2+ binds to calmodulin, which leads to the production of nitric oxide, causing vasodilation. Furthermore, the TRPV4 channel plays an important role in angiogenesis and arteriogenesis and is critical for tumor angiogenesis and growth, since it promotes or inhibits the development of various types of cancer. The TRPV4 channel is involved in the active growth of collateral arteries induced by flow shear stress, which makes it a promising therapeutic target in the occlusion or stenosis of the main arteries. In this review, we explore the role and the potential mechanism of action of the TRPV4 channel in the regulation of vascular tone and in the induction of neovascularization to provide a reference for future research.
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Affiliation(s)
- Miao Chen
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, China
| | - Xiucun Li
- Department of Hand and Foot Surgery, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Anatomy and Histoembryology, School of Basic Medical Science, Cheeloo College of Medicine, Shandong University, Jinan, China
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Mittal A, Park PD, Mitchell R, Fang H, Bagher P. Comparison of Adrenergic and Purinergic Receptor Contributions to Vasomotor Responses in Mesenteric Arteries of C57BL/6J Mice and Wistar Rats. J Vasc Res 2020; 58:1-15. [PMID: 33311016 DOI: 10.1159/000511462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/07/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The sympathetic nervous system can modulate arteriolar tone through release of adenosine triphosphate and norepinephrine, which bind to purinergic and adrenergic receptors (ARs), respectively. The expression pattern of these receptors, as well as the composition of neurotransmitters released from perivascular nerves (PVNs), can vary both in organ systems within and across species, such as mice and rats. OBJECTIVE This study explores the function of α1A subtypes in mouse and rat third-order mesenteric arteries and investigates PVN-mediated vasoconstriction to identify which neurotransmitters are released from sympathetic PVNs. METHODS Third-order mesenteric arteries from male C57BL/6J mice and Wistar rats were isolated and mounted on a wire myograph for functional assessment. Arteries were exposed to phenylephrine (PE) and then incubated with either α1A antagonist RS100329 (RS) or α1D antagonist BMY7378, before reexposure to PE. Electrical field stimulation was performed by passing current through platinum electrodes positioned adjacent to arteries in the absence and presence of a nonspecific alpha AR blocker phentolamine and/or P2X1-specific purinergic receptor blocker NF449. RESULTS Inhibition of α1 ARs by RS revealed that PE-induced vasoconstriction is primarily mediated through α1A and that the contribution of the α1A AR is greater in rats than in mice. In the mouse model, sympathetic nerve-mediated vasoconstriction is mediated by both ARs and purinergic receptors, whereas in rats, vasoconstriction appeared to only be mediated by ARs and a nonpurinergic neurotransmitter. Further, neither model demonstrated that α1D ARs play a significant role in PE-mediated vasoconstriction. CONCLUSIONS The mesenteric arteries of male C57BL/6J mice and Wistar rats have subtle differences in the signaling mechanisms used to mediate vasoconstriction. As signaling pathways in humans under physiological and pathophysiological conditions become better defined, the current study may inform animal model selection for preclinical studies.
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Affiliation(s)
- Astha Mittal
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Peter D Park
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Ray Mitchell
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Hanwei Fang
- Department of Microbiology and Molecular Medicine University of Geneva, Geneva, Switzerland
| | - Pooneh Bagher
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA,
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Aalkjær C, Nilsson H, De Mey JGR. Sympathetic and Sensory-Motor Nerves in Peripheral Small Arteries. Physiol Rev 2020; 101:495-544. [PMID: 33270533 DOI: 10.1152/physrev.00007.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Small arteries, which play important roles in controlling blood flow, blood pressure, and capillary pressure, are under nervous influence. Their innervation is predominantly sympathetic and sensory motor in nature, and while some arteries are densely innervated, others are only sparsely so. Innervation of small arteries is a key mechanism in regulating vascular resistance. In the second half of the previous century, the physiology and pharmacology of this innervation were very actively investigated. In the past 10-20 yr, the activity in this field was more limited. With this review we highlight what has been learned during recent years with respect to development of small arteries and their innervation, some aspects of excitation-release coupling, interaction between sympathetic and sensory-motor nerves, cross talk between endothelium and vascular nerves, and some aspects of their role in vascular inflammation and hypertension. We also highlight what remains to be investigated to further increase our understanding of this fundamental aspect of vascular physiology.
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Affiliation(s)
| | - Holger Nilsson
- Department Physiology, Gothenburg University, Gothenburg, Sweden
| | - Jo G R De Mey
- Deptartment Pharmacology and Personalized Medicine, Maastricht University, Maastricht, The Netherlands
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Zhuang XL, Zhu ZL, Zhu JL, Lai SM, Gui LX, Lin MJ. Synchronous detection of vascular tension and nitric oxide release in pulmonary artery: A combined application of confocal wire myograph with confocal laser scanning microscopy. Vascular 2020; 28:619-628. [PMID: 32295493 DOI: 10.1177/1708538120917555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To detect the vascular tension and nitric oxide (NO) release synchronously in mice pulmonary artery, we perform two experiments and present a novel application of confocal wire myograph coupled with the confocal laser scanning microscopy. METHODS In the first experiment, viable endothelium-intact mouse pulmonary artery (outer diameter 100-300 μM) rings underwent a one-hour preincubation with a NO-specific fluorescent dye, 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate Calbiochem (2.5 μM), and then precontracted with phenylephrine (Phen, 10-6 M), and subsequently dilated in acetylcholine (ACh, 10-6 M - 10-4 M). The endothelium-dependent vasorelaxation and NO generation in pulmonary artery rings were simultaneously recorded. In the second experiment, after 30-min incubation with the former NO fluorescent dye, the qualified pulmonary artery rings were co-incubated for another 30 min with a nitric oxide synthase inhibitor, 10-4 M Nω-nitro-L-arginine-methyl-ester (L-NAME), and then pretreated with Phen (10-6 M) followed by ACh (10-5 M). The Ach-induced vasodilation and NO release were recorded simultaneously. RESULTS ACh (10-6 M - 10-4 M) promoted pulmonary artery relaxation and intracellular NO release in a dose-dependent manner. Additionally, L-NAME (10-4 M) significantly attenuated the vasodilatation and the intracellular NO release. CONCLUSIONS This combined application visually confirms that the synchronous changes in Ach induced vasodilation and NO release, which provides a new method for cardiovascular research.
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Affiliation(s)
- Xiao-Ling Zhuang
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,Department of Pathology, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China
| | - Zhuang-Li Zhu
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jie-Ling Zhu
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Su-Mei Lai
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Long-Xin Gui
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Mo-Jun Lin
- Department of Physiology & Pathophysiology, The Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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11
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Lemmey HAL, Garland CJ, Dora KA. Intrinsic regulation of microvascular tone by myoendothelial feedback circuits. CURRENT TOPICS IN MEMBRANES 2020; 85:327-355. [PMID: 32402644 DOI: 10.1016/bs.ctm.2020.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The endothelium is an important regulator of arterial vascular tone, acting to release nitric oxide (NO) and open Ca2+-activated K+ (KCa) channels to relax vascular smooth muscle cells (VSMCs). While agonists acting at endothelial cell (EC) receptors are widely used to assess the ability of the endothelium to reduce vascular tone, the intrinsic EC-dependent mechanisms are less well characterized. In small resistance arteries and arterioles, the presence of heterocellular gap junctions termed myoendothelial gap junctions (MEGJs) allows the passage of not only current, but small molecules including Ca2+ and inositol trisphosphate (IP3). When stimulated to contract, the increase in VSM Ca2+ and IP3 can therefore potentially pass through MEGJs to activate adjacent ECs. This activation releases NO and opens KCa channels, which act to limit contraction. This myoendothelial feedback (MEF) is amplified by EC Ca2+ influx and release pathways, and is dynamically modulated by processes regulating gap junction conductance. There is a remarkable localization of key signaling and regulatory proteins within the EC projection toward VSM, and the intrinsic EC-dependent signaling pathways occurring with this highly specialized microdomain are reviewed.
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Affiliation(s)
- Hamish A L Lemmey
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | | | - Kim A Dora
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
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12
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Ion channels and the regulation of myogenic tone in peripheral arterioles. CURRENT TOPICS IN MEMBRANES 2020; 85:19-58. [DOI: 10.1016/bs.ctm.2020.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Mewes M, Lenders M, Stappers F, Scharnetzki D, Nedele J, Fels J, Wedlich-Söldner R, Brand SM, Schmitz B, Brand E. Soluble adenylyl cyclase (sAC) regulates calcium signaling in the vascular endothelium. FASEB J 2019; 33:13762-13774. [PMID: 31585052 DOI: 10.1096/fj.201900724r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The vascular endothelium acts as a selective barrier between the bloodstream and extravascular tissues. Intracellular [Ca2+]i signaling is essential for vasoactive agonist-induced stimulation of endothelial cells (ECs), typically including Ca2+ release from the endoplasmic reticulum (ER). Although it is known that interactions of Ca2+ and cAMP as ubiquitous messengers are involved in this process, the individual contribution of cAMP-generating adenylyl cyclases (ACs), including the only soluble AC (sAC; ADCY10), remains less clear. Using life-cell microscopy and plate reader-based [Ca2+]i measurements, we found that human immortalized ECs, primary aortic and cardiac microvascular ECs, and primary vascular smooth muscle cells treated with sAC-specific inhibitor KH7 or anti-sAC-small interfering RNA did not show endogenous or exogenous ATP-induced [Ca2+]i elevation. Of note, a transmembrane AC (tmAC) inhibitor did not prevent ATP-induced [Ca2+]i elevation in ECs. Moreover, l-phenylephrine-dependent constriction of ex vivo mouse aortic ring segments was also reduced by KH7. Analysis of the inositol-1,4,5-trisphosphate (IP3) pathway revealed reduced IP3 receptor phosphorylation after KH7 application, which also prevented [Ca2+]i elevation induced by IP3 receptor agonist adenophostin A. Our results suggest that sAC rather than tmAC controls the agonist-induced ER-dependent Ca2+ response in ECs and may represent a treatment target in arterial hypertension and heart failure.-Mewes, M., Lenders, M., Stappers, F., Scharnetzki, D., Nedele, J., Fels, J., Wedlich-Söldner, R., Brand, S.-M., Schmitz, B., Brand, E. Soluble adenylyl cyclase (sAC) regulates calcium signaling in the vascular endothelium.
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Affiliation(s)
- Mirja Mewes
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Malte Lenders
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Franciska Stappers
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - David Scharnetzki
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Johanna Nedele
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Johannes Fels
- Institute for Cell Dynamics and Imaging, Medical Faculty, University of Muenster, Muenster, Germany.,Department of Physiology, Pathophysiology, and Toxicology and Center for Biomedical Education and Research (ZBAF), University of Witten/Herdecke, Witten, Germany
| | - Roland Wedlich-Söldner
- Institute for Cell Dynamics and Imaging, Medical Faculty, University of Muenster, Muenster, Germany
| | - Stefan-Martin Brand
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Muenster, Germany
| | - Boris Schmitz
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Muenster, Germany
| | - Eva Brand
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
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14
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Wilson C, Zhang X, Buckley C, Heathcote HR, Lee MD, McCarron JG. Increased Vascular Contractility in Hypertension Results From Impaired Endothelial Calcium Signaling. Hypertension 2019; 74:1200-1214. [PMID: 31542964 PMCID: PMC6791503 DOI: 10.1161/hypertensionaha.119.13791] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Supplemental Digital Content is available in the text. Endothelial cells line all blood vessels and are critical regulators of vascular tone. In hypertension, disruption of endothelial function alters the release of endothelial-derived vasoactive factors and results in increased vascular tone. Although the release of endothelial-derived vasodilators occurs in a Ca2+-dependent manner, little is known on how Ca2+ signaling is altered in hypertension. A key element to endothelial control of vascular tone is Ca2+ signals at specialized regions (myoendothelial projections) that connect endothelial cells and smooth muscle cells. This work describes disruption in the operation of this key Ca2+ signaling pathway in hypertension. We show that vascular reactivity to phenylephrine is increased in hypertensive (spontaneously hypertensive rat) when compared with normotensive (Wistar Kyoto) rats. Basal endothelial Ca2+ activity limits vascular contraction, but that Ca2+-dependent control is impaired in hypertension. When changes in endothelial Ca2+ levels are buffered, vascular contraction to phenylephrine increased, resulting in similar responses in normotension and hypertension. Local endothelial IP3(inositol trisphosphate)-mediated Ca2+ signals are smaller in amplitude, shorter in duration, occur less frequently, and arise from fewer sites in hypertension. Spatial control of endothelial Ca2+ signaling is also disrupted in hypertension: local Ca2+ signals occur further from myoendothelial projections in hypertension. The results demonstrate that the organization of local Ca2+ signaling circuits occurring at myoendothelial projections is disrupted in hypertension, giving rise to increased contractile responses.
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Affiliation(s)
- Calum Wilson
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Xun Zhang
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Charlotte Buckley
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Helen R Heathcote
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Matthew D Lee
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - John G McCarron
- From the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
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15
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Mishra RC, Rahman MM, Davis MJ, Wulff H, Hill MA, Braun AP. Alpha 1 -adrenergic stimulation selectively enhances endothelium-mediated vasodilation in rat cremaster arteries. Physiol Rep 2019; 6:e13703. [PMID: 29756401 PMCID: PMC5949301 DOI: 10.14814/phy2.13703] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/19/2018] [Accepted: 04/16/2018] [Indexed: 11/24/2022] Open
Abstract
We have systematically investigated how vascular smooth muscle α1‐adrenoceptor activation impacts endothelium‐mediated vasodilation in isolated, myogenically active, rat cremaster muscle 1A arteries. Cannulated cremaster arteries were pressurized intraluminally to 70 mmHg to induce myogenic tone, and exposed to vasoactive agents via bath superfusion at 34°C. Smooth muscle membrane potential was measured via sharp microelectrode recordings in pressurized, myogenic arteries. The α1‐adrenergic agonist phenylephrine (25–100 nmol/L) produced further constriction of myogenic arteries, but did not alter the vasorelaxant responses to acetylcholine (0.3 μmol/L), SKA‐31 (an activator of endothelial Ca2+‐dependent K+ channels) (3 μmol/L) or sodium nitroprusside (10 μmol/L). Exposure to 0.25–1 μmol/L phenylephrine or 1 μmol/L norepinephrine generated more robust constrictions, and also enhanced the vasodilations evoked by acetylcholine and SKA‐31, but not by sodium nitroprusside. In contrast, the thromboxane receptor agonist U46619 (250 nmol/L) dampened responses to all three vasodilators. Phenylephrine exposure depolarized myogenic arteries, and mimicking this effect with 4‐aminopyridine (1 mmol/L) was sufficient to augment the SKA‐31‐evoked vasodilation. Inhibition of L‐type Ca2+ channels by 1 μmol/L nifedipine decreased myogenic tone, phenylephrine‐induced constriction and prevented α1‐adrenergic enhancement of endothelium‐evoked vasodilation; these latter deficits were overcome by exposure to 3 and 10 μmol/L phenylephrine. Mechanistically, augmentation of ACh‐evoked dilation by phenylephrine was dampened by eNOS inhibition and abolished by blockade of endothelial KCa channels. Collectively, these data suggest that increasing α1‐adrenoceptor activation beyond a threshold level augments endothelium‐evoked vasodilation, likely by triggering transcellular signaling between smooth muscle and the endothelium. Physiologically, this negative feedback process may serve as a “brake” to limit the extent of vasoconstriction in the skeletal microcirculation evoked by the elevated sympathetic tone.
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Affiliation(s)
- Ramesh C Mishra
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Mohammad M Rahman
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael J Davis
- Dalton Cardiovascular Research Institute and Dept. of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, Davis, California
| | - Michael A Hill
- Dalton Cardiovascular Research Institute and Dept. of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Andrew P Braun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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16
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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.
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17
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DeLalio LJ, Billaud M, Ruddiman CA, Johnstone SR, Butcher JT, Wolpe AG, Jin X, Keller TCS, Keller AS, Rivière T, Good ME, Best AK, Lohman AW, Swayne LA, Penuela S, Thompson RJ, Lampe PD, Yeager M, Isakson BE. Constitutive SRC-mediated phosphorylation of pannexin 1 at tyrosine 198 occurs at the plasma membrane. J Biol Chem 2019; 294:6940-6956. [PMID: 30814251 DOI: 10.1074/jbc.ra118.006982] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/15/2019] [Indexed: 11/06/2022] Open
Abstract
Pannexin 1 (PANX1)-mediated ATP release in vascular smooth muscle coordinates α1-adrenergic receptor (α1-AR) vasoconstriction and blood pressure homeostasis. We recently identified amino acids 198-200 (YLK) on the PANX1 intracellular loop that are critical for α1-AR-mediated vasoconstriction and PANX1 channel function. We report herein that the YLK motif is contained within an SRC homology 2 domain and is directly phosphorylated by SRC proto-oncogene, nonreceptor tyrosine kinase (SRC) at Tyr198 We demonstrate that PANX1-mediated ATP release occurs independently of intracellular calcium but is sensitive to SRC family kinase (SFK) inhibition, suggestive of channel regulation by tyrosine phosphorylation. Using a PANX1 Tyr198-specific antibody, SFK inhibitors, SRC knockdown, temperature-dependent SRC cells, and kinase assays, we found that PANX1-mediated ATP release and vasoconstriction involves constitutive phosphorylation of PANX1 Tyr198 by SRC. We specifically detected SRC-mediated Tyr198 phosphorylation at the plasma membrane and observed that it is not enhanced or induced by α1-AR activation. Last, we show that PANX1 immunostaining is enriched in the smooth muscle layer of arteries from hypertensive humans and that Tyr198 phosphorylation is detectable in these samples, indicative of a role for membrane-associated PANX1 in small arteries of hypertensive humans. Our discovery adds insight into the regulation of PANX1 by post-translational modifications and connects a significant purinergic vasoconstriction pathway with a previously identified, yet unexplored, tyrosine kinase-based α1-AR constriction mechanism. This work implicates SRC-mediated PANX1 function in normal vascular hemodynamics and suggests that Tyr198-phosphorylated PANX1 is involved in hypertensive vascular pathology.
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Affiliation(s)
- Leon J DeLalio
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | - Marie Billaud
- the Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Claire A Ruddiman
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | | | - Joshua T Butcher
- the Department of Physiology, Augusta University, Augusta, Georgia 30912
| | - Abigail G Wolpe
- From the Robert M. Berne Cardiovascular Research Center.,Department of Cell Biology, and
| | - Xueyao Jin
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - T C Stevenson Keller
- From the Robert M. Berne Cardiovascular Research Center.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Alexander S Keller
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | - Thibaud Rivière
- the Department of Life and Health Sciences, University of Bordeaux, 33000 Bordeaux, France
| | | | - Angela K Best
- From the Robert M. Berne Cardiovascular Research Center
| | - Alexander W Lohman
- the Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Leigh Anne Swayne
- the Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Silvia Penuela
- the Departments of Anatomy and Cell Biology and Oncology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 3K7, Canada, and
| | - Roger J Thompson
- the Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Paul D Lampe
- the Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Mark Yeager
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center, .,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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18
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Williams IM, McClatchey PM, Bracy DP, Valenzuela FA, Wasserman DH. Acute Nitric Oxide Synthase Inhibition Accelerates Transendothelial Insulin Efflux In Vivo. Diabetes 2018; 67:1962-1975. [PMID: 30002132 PMCID: PMC6152344 DOI: 10.2337/db18-0288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022]
Abstract
Before insulin can stimulate glucose uptake in muscle, it must be delivered to skeletal muscle (SkM) through the microvasculature. Insulin delivery is determined by SkM perfusion and the rate of movement of insulin across the capillary endothelium. The endothelium therefore plays a central role in regulating insulin access to SkM. Nitric oxide (NO) is a key regulator of endothelial function and stimulates arterial vasodilation, which increases SkM perfusion and the capillary surface area available for insulin exchange. The effects of NO on transendothelial insulin efflux (TIE), however, are unknown. We hypothesized that acute reduction of endothelial NO would reduce TIE. However, intravital imaging of TIE in mice revealed that reduction of NO by l-NG-nitro-l-arginine methyl ester (l-NAME) enhanced the rate of TIE by ∼30% and increased total extravascular insulin delivery. This accelerated TIE was associated with more rapid insulin-stimulated glucose lowering. Sodium nitroprusside, an NO donor, had no effect on TIE in mice. The effects of l-NAME on TIE were not due to changes in blood pressure alone, as a direct-acting vasoconstrictor (phenylephrine) did not affect TIE. These results demonstrate that acute NO synthase inhibition increases the permeability of capillaries to insulin, leading to an increase in delivery of insulin to SkM.
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Affiliation(s)
- Ian M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - P Mason McClatchey
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | | | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
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19
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DeLalio LJ, Keller AS, Chen J, Boyce AK, Artamonov M, Askew-Page HR, Keller TS, Johnstone SR, Weaver RB, Good ME, Murphy S, Best AK, Mintz EL, Penuela S, Greenwood I, Machado RF, Somlyo AV, Swayne LA, Minshall R, Isakson BE. Interaction Between Pannexin 1 and Caveolin-1 in Smooth Muscle Can Regulate Blood Pressure. Arterioscler Thromb Vasc Biol 2018; 38:2065-2078. [PMID: 30026274 PMCID: PMC6202122 DOI: 10.1161/atvbaha.118.311290] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 06/19/2018] [Indexed: 12/31/2022]
Abstract
Objective- Sympathetic nerve innervation of vascular smooth muscle cells (VSMCs) is a major regulator of arteriolar vasoconstriction, vascular resistance, and blood pressure. Importantly, α-adrenergic receptor stimulation, which uniquely couples with Panx1 (pannexin 1) channel-mediated ATP release in resistance arteries, also requires localization to membrane caveolae. Here, we test whether localization of Panx1 to Cav1 (caveolin-1) promotes channel function (stimulus-dependent ATP release and adrenergic vasoconstriction) and is important for blood pressure homeostasis. Approach and Results- We use in vitro VSMC culture models, ex vivo resistance arteries, and a novel inducible VSMC-specific Cav1 knockout mouse to probe interactions between Panx1 and Cav1. We report that Panx1 and Cav1 colocalized on the VSMC plasma membrane of resistance arteries near sympathetic nerves in an adrenergic stimulus-dependent manner. Genetic deletion of Cav1 significantly blunts adrenergic-stimulated ATP release and vasoconstriction, with no direct influence on endothelium-dependent vasodilation or cardiac function. A significant reduction in mean arterial pressure (total=4 mm Hg; night=7 mm Hg) occurred in mice deficient for VSMC Cav1. These animals were resistant to further blood pressure lowering using a Panx1 peptide inhibitor Px1IL2P, which targets an intracellular loop region necessary for channel function. Conclusions- Translocalization of Panx1 to Cav1-enriched caveolae in VSMCs augments the release of purinergic stimuli necessary for proper adrenergic-mediated vasoconstriction and blood pressure homeostasis.
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Affiliation(s)
- Leon J. DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Alexander S. Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Jiwang Chen
- Department of Medicine, The University of Illinois at Chicago, Chicago, IL
| | - Andrew K.J. Boyce
- Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, BC Canada
| | - Mykhaylo Artamonov
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Henry R. Askew-Page
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - T.C. Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Scott R. Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Rachel B. Weaver
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Miranda E. Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Sara Murphy
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Angela K. Best
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Ellen L. Mintz
- Department of Biomedical Engineering, University of Virginia School of Engineering, Charlottesville, VA
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, Schulich Scholl of Medicine and Dentistry, University of Western Ontario, London ON, Canada
| | - Iain Greenwood
- Molecular and Clinical Sciences Research Institute, St. George’s University London UK
| | - Roberto F. Machado
- Division of Pulmonary, Critical Care, Sleep, & Occupational Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Avril V. Somlyo
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Leigh Anne Swayne
- Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, BC Canada
| | - Richard Minshall
- Department of Pharmacology and Department of Anesthesiology, The University of Illinois at Chicago, Chicago, IL
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
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20
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Looft‐Wilson RC, Todd SE, Berberich KM, Wolfert MR. Flow does not alter eNOS phosphoryation at Ser1179 or Thr495 in preconstricted mouse mesenteric arteries. Physiol Rep 2018; 6:e13864. [PMID: 30247813 PMCID: PMC6129772 DOI: 10.14814/phy2.13864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 12/23/2022] Open
Abstract
In arteries, endothelium-dependent vasodilatory agonists and flow-induced shear stress cause vasodilation largely by activation of the endothelial enzyme eNOS, which generates nitric oxide that relaxes vascular smooth muscle. Agonists activate eNOS in part through increased phosphorylation at Ser1179 and decreased phosphorylation at Thr495. We previously found that preconstriction of intact, isolated mouse mesenteric arteries with phenylephrine also caused increased Ser1179 and decreased Thr495 eNOS phosphorylation, and sequential treatment with the vasodilatory agonist acetylcholine did not cause any further change in phosphorylation at these sites, despite producing vasodilation. The present study tests the hypothesis that luminal flow in these arteries preconstricted with phenylephrine also produces vasodilation without phosphorylation changes at these sites. First-order mesenteric arteries, isolated from male C57/BL6 mice (7-20 weeks of age) anesthetized with pentobarbital (50 mg/kg, i.p.), were cannulated, pressurized, and treated with stepped increases in luminal flow (15-120 μL/min). Flow resulted in dilation that plateaued at ~60 μL/min (31.3 ± 3.0% dilation) and was significantly (P < 0.001) NOS-dependent at all flow rates (determined by 10-4 mol/L L-NAME treatment). In separate arteries, preconstriction with phenylephrine (10-5 mol/L) resulted in increased eNOS phosphorylation at Ser1179 (P < 0.05) and decreased phosphorylation at Thr495, but subsequent flow at 60 μL/min for 5 or 15 min did not cause further changes in phosphorylation, despite causing dilation. Thus, flow-induced dilation does not require changes in these eNOS phosphorylation sites beyond those induced by alpha1-adrenergic stimulation with phenylephrine, indicating that eNOS is activated by other mechanisms during acute flow-induced dilation of preconstricted arteries.
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Affiliation(s)
- Robin C. Looft‐Wilson
- Department of Kinesiology and Health SciencesThe College of William & MaryWilliamsburgVirginia
| | - Sarah E. Todd
- Department of Kinesiology and Health SciencesThe College of William & MaryWilliamsburgVirginia
| | - Kristen M. Berberich
- Department of Kinesiology and Health SciencesThe College of William & MaryWilliamsburgVirginia
| | - Madeline R. Wolfert
- Department of Kinesiology and Health SciencesThe College of William & MaryWilliamsburgVirginia
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21
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Jackson WF, Boerman EM. Voltage-gated Ca 2+ channel activity modulates smooth muscle cell calcium waves in hamster cremaster arterioles. Am J Physiol Heart Circ Physiol 2018; 315:H871-H878. [PMID: 29957015 DOI: 10.1152/ajpheart.00292.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cremaster muscle arteriolar smooth muscle cells (SMCs) display inositol 1,4,5-trisphosphate receptor-dependent Ca2+ waves that contribute to global myoplasmic Ca2+ concentration and myogenic tone. However, the contribution made by voltage-gated Ca2+ channels (VGCCs) to arteriolar SMC Ca2+ waves is unknown. We tested the hypothesis that VGCC activity modulates SMC Ca2+ waves in pressurized (80 cmH2O/59 mmHg, 34°C) hamster cremaster muscle arterioles loaded with Fluo-4 and imaged by confocal microscopy. Removal of extracellular Ca2+ dilated arterioles (32 ± 3 to 45 ± 3 μm, n = 15, P < 0.05) and inhibited the occurrence, amplitude, and frequency of Ca2+ waves ( n = 15, P < 0.05), indicating dependence of Ca2+ waves on Ca2+ influx. Blockade of VGCCs with nifedipine (1 μM) or diltiazem (10 μM) or deactivation of VGCCs by hyperpolarization of smooth muscle with the K+ channel agonist cromakalim (10 μM) produced similar inhibition of Ca2+ waves ( P < 0.05). Conversely, depolarization of SMCs with the K+ channel blocker tetraethylammonium (1 mM) constricted arterioles from 26 ± 3 to 14 ± 2 μm ( n = 11, P < 0.05) and increased wave occurrence (9 ± 3 to 16 ± 3 waves/SMC), amplitude (1.6 ± 0.07 to 1.9 ± 0.1), and frequency (0.5 ± 0.1 to 0.9 ± 0.2 Hz, n = 10, P < 0.05), effects that were blocked by nifedipine (1 μM, P < 0.05). Similarly, the VGCC agonist Bay K8644 (5 nM) constricted arterioles from 14 ± 1 to 8 ± 1 μm and increased wave occurrence (3 ± 1 to 10 ± 1 waves/SMC) and frequency (0.2 ± 0.1 to 0.6 ± 0.1 Hz, n = 6, P < 0.05), effects that were unaltered by ryanodine (50 μM, n = 6, P > 0.05). These data support the hypothesis that Ca2+ waves in arteriolar SMCs depend, in part, on the activity of VGCCs. NEW & NOTEWORTHY Arterioles that control blood flow to and within skeletal muscle depend on Ca2+ influx through voltage-gated Ca2+ channels and release of Ca2+ from internal stores through inositol 1,4,5-trisphosphate receptors in the form of Ca2+ waves to maintain pressure-induced smooth muscle tone.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Erika M Boerman
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
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22
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Hong K, Cope EL, DeLalio LJ, Marziano C, Isakson BE, Sonkusare SK. TRPV4 (Transient Receptor Potential Vanilloid 4) Channel-Dependent Negative Feedback Mechanism Regulates G q Protein-Coupled Receptor-Induced Vasoconstriction. Arterioscler Thromb Vasc Biol 2018; 38:542-554. [PMID: 29301784 DOI: 10.1161/atvbaha.117.310038] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/18/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Several physiological stimuli activate smooth muscle cell (SMC) GqPCRs (Gq protein-coupled receptors) to cause vasoconstriction. As a protective mechanism against excessive vasoconstriction, SMC GqPCR stimulation invokes endothelial cell vasodilatory signaling. Whether Ca2+ influx in endothelial cells contributes to the regulation of GqPCR-induced vasoconstriction remains unknown. Ca2+ influx through TRPV4 (transient receptor potential vanilloid 4) channels is a key regulator of endothelium-dependent vasodilation. We hypothesized that SMC GqPCR stimulation engages endothelial TRPV4 channels to limit vasoconstriction. APPROACH AND RESULTS Using high-speed confocal microscopy to record unitary Ca2+ influx events through TRPV4 channels (TRPV4 sparklets), we report that activation of SMC α1ARs (alpha1-adrenergic receptors) with phenylephrine or thromboxane A2 receptors with U46619 stimulated TRPV4 sparklets in the native endothelium from mesenteric arteries. Activation of endothelial TRPV4 channels did not require an increase in Ca2+ as indicated by the lack of effect of L-type Ca2+ channel activator or chelator of intracellular Ca2+ EGTA-AM. However, gap junction communication between SMCs and endothelial cells was required for phenylephrine activation or U46619 activation of endothelial TRPV4 channels. Lowering inositol 1,4,5-trisphosphate levels with phospholipase C inhibitor or lithium chloride suppressed phenylephrine activation of endothelial TRPV4 sparklets. Moreover, uncaging inositol 1,4,5-trisphosphate profoundly increased TRPV4 sparklet activity. In pressurized arteries, phenylephrine-induced vasoconstriction was followed by a slow, TRPV4-dependent vasodilation, reflecting activation of negative regulatory mechanism. Consistent with these data, phenylephrine induced a significantly higher increase in blood pressure in TRPV4-/- mice. CONCLUSIONS These results demonstrate that SMC GqPCR stimulation triggers inositol 1,4,5-trisphosphate-dependent activation of endothelial TRPV4 channels to limit vasoconstriction.
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Affiliation(s)
- Kwangseok Hong
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Eric L Cope
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Leon J DeLalio
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Corina Marziano
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Swapnil K Sonkusare
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville.
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23
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Biwer LA, Good ME, Hong K, Patel RK, Agrawal N, Looft-Wilson R, Sonkusare SK, Isakson BE. Non-Endoplasmic Reticulum-Based Calr (Calreticulin) Can Coordinate Heterocellular Calcium Signaling and Vascular Function. Arterioscler Thromb Vasc Biol 2018; 38:120-130. [PMID: 29122814 PMCID: PMC5746467 DOI: 10.1161/atvbaha.117.309886] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/25/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In resistance arteries, endothelial cell (EC) extensions can make contact with smooth muscle cells, forming myoendothelial junction at holes in the internal elastic lamina (HIEL). At these HIEL, calcium signaling is tightly regulated. Because Calr (calreticulin) can buffer ≈50% of endoplasmic reticulum calcium and is expressed throughout IEL holes in small arteries, the only place where myoendothelial junctions form, we investigated the effect of EC-specific Calr deletion on calcium signaling and vascular function. APPROACH AND RESULTS We found Calr expressed in nearly every IEL hole in third-order mesenteric arteries, but not other ER markers. Because of this, we generated an EC-specific, tamoxifen inducible, Calr knockout mouse (EC Calr Δ/Δ). Using this mouse, we tested third-order mesenteric arteries for changes in calcium events at HIEL and vascular reactivity after application of CCh (carbachol) or PE (phenylephrine). We found that arteries from EC Calr Δ/Δ mice stimulated with CCh had unchanged activity of calcium signals and vasodilation; however, the same arteries were unable to increase calcium events at HIEL in response to PE. This resulted in significantly increased vasoconstriction to PE, presumably because of inhibited negative feedback. In line with these observations, the EC Calr Δ/Δ had increased blood pressure. Comparison of ER calcium in arteries and use of an ER-specific GCaMP indicator in vitro revealed no observable difference in ER calcium with Calr knockout. Using selective detergent permeabilization of the artery and inhibition of Calr translocation, we found that the observed Calr at HIEL may not be within the ER. CONCLUSIONS Our data suggest that Calr specifically at HIEL may act in a non-ER dependent manner to regulate arteriolar heterocellular communication and blood pressure.
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Affiliation(s)
- Lauren A Biwer
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Miranda E Good
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Kwangseok Hong
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Rahul K Patel
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Neha Agrawal
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Robin Looft-Wilson
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Swapnil K Sonkusare
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.)
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center (L.A.B., M.E.G., K.H., R.K.P., S.K.S., B.E.I.) and Department of Molecular Physiology and Biophysics (L.A.B., S.K.S., B.E.I.), University of Virginia School of Medicine, Charlottesville; and Department of Kinesiology, College of William and Mary, Williamsburg, VA (N.A., R.L.-W.).
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Garland CJ, Bagher P, Powell C, Ye X, Lemmey HAL, Borysova L, Dora KA. Voltage-dependent Ca 2+ entry into smooth muscle during contraction promotes endothelium-mediated feedback vasodilation in arterioles. Sci Signal 2017; 10:10/486/eaal3806. [PMID: 28676489 DOI: 10.1126/scisignal.aal3806] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vascular smooth muscle contraction is suppressed by feedback dilation mediated by the endothelium. In skeletal muscle arterioles, this feedback can be activated by Ca2+ signals passing from smooth muscle through gap junctions to endothelial cells, which protrude through holes in the internal elastic lamina to make contact with vascular smooth muscle cells. Although hypothetically either Ca2+ or inositol trisphosphate (IP3) may provide the intercellular signal, it is generally thought that IP3 diffusion is responsible. We provide evidence that Ca2+ entry through L-type voltage-dependent Ca2+ channels (VDCCs) in vascular smooth muscle can pass to the endothelium through positions aligned with holes in the internal elastic lamina in amounts sufficient to activate endothelial cell Ca2+ signaling. In endothelial cells in which IP3 receptors (IP3Rs) were blocked, VDCC-driven Ca2+ events were transient and localized to the endothelium that protrudes through the internal elastic lamina to contact vascular smooth muscle cells. In endothelial cells in which IP3Rs were not blocked, VDCC-driven Ca2+ events in endothelial cells were amplified to form propagating waves. These waves activated voltage-insensitive, intermediate-conductance, Ca2+-activated K+ (IKCa) channels, thereby providing feedback that effectively suppressed vasoconstriction and enabled cycles of constriction and dilation called vasomotion. Thus, agonists that stimulate vascular smooth muscle depolarization provide Ca2+ to endothelial cells to activate a feedback circuit that protects tissue blood flow.
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Affiliation(s)
- Christopher J Garland
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Pooneh Bagher
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Chloe Powell
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Hamish A L Lemmey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Lyudmyla Borysova
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Kim A Dora
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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25
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Jackson WF, Boerman EM. Regional heterogeneity in the mechanisms of myogenic tone in hamster arterioles. Am J Physiol Heart Circ Physiol 2017; 313:H667-H675. [PMID: 28667050 DOI: 10.1152/ajpheart.00183.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/07/2017] [Accepted: 06/26/2017] [Indexed: 01/30/2023]
Abstract
Myogenic tone is an important feature of arterioles and resistance arteries, but the mechanisms responsible for this hallmark characteristic remain unclear. We used pharmacological inhibitors to compare the roles played by phospholipase C (PLC; 10 μM U73122), inositol 1,4,5-trisphosphate receptors (IP3Rs; 100 μM 2-aminoethoxydiphenylborane), protein kinase C (10 μM bisindolylmaleimide I), angiotensin II type 1 receptors (1 μM losartan), Rho kinase (10 nM-30 μM Y27632 or 300 nM H1152), stretch-activated ion channels (10 nM-1 μM Gd3+ or 5 μM spider venom toxin GsMTx-4) and L-type voltage-gated Ca2+ channels (0.3-100 μM diltiazem) in myogenic tone of cannulated, pressurized (80 cmH2O), second-order hamster cremaster or cheek pouch arterioles. Effective inhibition of either PLC or IP3Rs dilated cremaster arterioles, inhibited Ca2+ waves, and reduced global Ca2+ levels. In contrast, cheek pouch arterioles did not display Ca2+ waves and inhibition of PLC or IP3Rs had no effect on myogenic tone or intracellular Ca2+ levels. Inhibition of Rho kinase dilated both cheek pouch and cremaster arterioles with equal efficacy and potency but also reduced intracellular Ca2+ signals in both arterioles. Similarly, inhibition of mechanosensitive ion channels with Gd2+ or GsMTx-4 produced comparable dilation in both arterioles. Inhibition of L-type Ca2+ channels with diltiazem was more effective in dilating cremaster (86 ± 5% dilation, n = 4) than cheek pouch arterioles (54 ± 4% dilation, n = 6, P < 0.05). Thus, there are substantial differences in the mechanisms underlying myogenic tone in hamster cremaster and cheek pouch arterioles. Regional heterogeneity in myogenic mechanisms could provide new targets for drug development to improve regional blood flow in a tissue-specific manner.NEW & NOTEWORTHY Regional heterogeneity in the mechanisms of pressure-induced myogenic tone implies that resistance vessels may be able to alter myogenic signaling pathways to adapt to their environment. A better understanding of the spectrum of myogenic mechanisms could provide new targets to treat diseases that affect resistance artery and arteriolar function.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Erika M Boerman
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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26
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Hayoz S, Pettis J, Bradley V, Segal SS, Jackson WF. Increased amplitude of inward rectifier K + currents with advanced age in smooth muscle cells of murine superior epigastric arteries. Am J Physiol Heart Circ Physiol 2017; 312:H1203-H1214. [PMID: 28432059 PMCID: PMC6146378 DOI: 10.1152/ajpheart.00679.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 04/18/2017] [Accepted: 04/18/2017] [Indexed: 01/15/2023]
Abstract
Inward rectifier K+ channels (KIR) may contribute to skeletal muscle blood flow regulation and adapt to advanced age. Using mouse abdominal wall superior epigastric arteries (SEAs) from either young (3-6 mo) or old (24-26 mo) male C57BL/6 mice, we investigated whether SEA smooth muscle cells (SMCs) express functional KIR channels and how aging may affect KIR function. Freshly dissected SEAs were either enzymatically dissociated to isolate SMCs for electrophysiological recording (perforated patch) and mRNA expression or used intact for pressure myography. With 5 mM extracellular K+ concentration ([K+]o), exposure of SMCs to the KIR blocker Ba2+ (100 μM) had no significant effect (P > 0.05) on whole cell currents elicited by membrane potentials spanning -120 to -30 mV. Raising [K+]o to 15 mM activated Ba2+-sensitive KIR currents between -120 and -30 mV, which were greater in SMCs from old mice than in SMCs from young mice (P < 0.05). Pressure myography of SEAs revealed that while aging decreased maximum vessel diameter by ~8% (P < 0.05), it had no significant effect on resting diameter, myogenic tone, dilation to 15 mM [K+]o, Ba2+-induced constriction in 5 mM [K+]o, or constriction induced by 15 mM [K+]o in the presence of Ba2+ (P > 0.05). Quantitative RT-PCR revealed SMC expression of KIR2.1 and KIR2.2 mRNA that was not affected by age. Barium-induced constriction of SEAs from young and old mice suggests an integral role for KIR in regulating resting membrane potential and vasomotor tone. Increased functional expression of KIR channels during advanced age may compensate for other age-related changes in SEA function.NEW & NOTEWORTHY Ion channels are integral to blood flow regulation. We found greater functional expression of inward rectifying K+ channels in smooth muscle cells of resistance arteries of mouse skeletal muscle with advanced age. This adaptation to aging may contribute to the maintenance of vasomotor tone and blood flow regulation during exercise.
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Affiliation(s)
- Sebastien Hayoz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Jessica Pettis
- College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Vanessa Bradley
- College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan;
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27
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Xu J, Chen L, Li L. Pannexin hemichannels: A novel promising therapy target for oxidative stress related diseases. J Cell Physiol 2017; 233:2075-2090. [PMID: 28295275 DOI: 10.1002/jcp.25906] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 03/09/2017] [Indexed: 12/16/2022]
Abstract
Pannexins, which contain three subtypes: pannexin-1, -2, and -3, are vertebrate glycoproteins that form non-junctional plasma membrane intracellular hemichannels via oligomerization. Oxidative stress refers to an imbalance of the generation and elimination of reactive oxygen species (ROS). Studies have shown that elevated ROS levels are pivotal in the development of a variety of diseases. Recent studies indicate that the occurrence of these oxidative stress related diseases is associated with pannexin hemichannels. It is also reported that pannexins regulate the production of ROS which in turn may increase the opening of pannexin hemichannels. In this paper, we review recent researches about the important role of pannexin hemichannels in oxidative stress related diseases. Thus, pannexin hemichannels, novel therapeutic targets, hold promise in managing oxidative stress related diseases such as the tumor, inflammatory bowel diseases (IBD), pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), cardiovascular disease, insulin resistance (IR), and neural degeneration diseases.
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Affiliation(s)
- Jin Xu
- Learning Key Laboratory for Pharmacoproteomics, Institute of Pharmacy and Pharmacology, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, P. R. China
| | - Linxi Chen
- Learning Key Laboratory for Pharmacoproteomics, Institute of Pharmacy and Pharmacology, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, P. R. China
| | - Lanfang Li
- Learning Key Laboratory for Pharmacoproteomics, Institute of Pharmacy and Pharmacology, University of South China, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, P. R. China
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28
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Abstract
Pannexin channels are newly discovered ATP release channels expressed throughout the body. Pannexin 1 (Panx1) channels have become of great interest as they appear to participate in a multitude of signalling cascades, including regulation of vascular function. Although numerous Panx1 pharmacological inhibitors have been discovered, these inhibitors are not specific for Panx1 and have additional effects on other proteins. Therefore, molecular tools, such as RNA interference and knockout animals, are needed to demonstrate the role of pannexins in various cellular functions. This review focuses on the known roles of Panx1 related to purinergic signalling in the vasculature focusing on post-translational modifications and channel gating mechanisms that may participate in the regulated release of ATP.
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Segal SS. Integration and Modulation of Intercellular Signaling Underlying Blood Flow Control. J Vasc Res 2015; 52:136-57. [PMID: 26368324 DOI: 10.1159/000439112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 07/30/2015] [Indexed: 01/25/2023] Open
Abstract
Vascular resistance networks control tissue blood flow in concert with regulating arterial perfusion pressure. In response to increased metabolic demand, vasodilation arising in arteriolar networks ascends to encompass proximal feed arteries. By reducing resistance upstream, ascending vasodilation (AVD) increases blood flow into the microcirculation. Once initiated, e.g. through local activation of K(+) channels in endothelial cells (ECs), hyperpolarization is conducted through gap junctions along the endothelium. Via EC projections through the internal elastic lamina, hyperpolarization spreads into the surrounding smooth-muscle cells (SMCs) through myoendothelial gap junctions (MEGJs) to promote their relaxation. Intercellular signaling through electrical signal transmission (i.e. cell-to-cell conduction) can thereby coordinate vasodilation along and among the branches of microvascular resistance networks. Perivascular sympathetic nerve fibers course through the adventitia and release norepinephrine to stimulate SMCs via α-adrenoreceptors to produce contraction. In turn, SMCs can signal ECs through MEGJs to activate K(+) channels and attenuate sympathetic vasoconstriction. Activation of K(+) channels along the endothelium will dissipate electrical signal transmission and inhibit AVD, thereby restricting blood flow into the microcirculation while maintaining peripheral resistance and perfusion pressure. This review explores the origins and nature of the intercellular signaling that governs blood flow control in skeletal muscle with respect to the interplay between AVD and sympathetic innervation. Whereas these interactions are integral to daily activity and athletic performance, determining the interplay between respective signaling events provides insight into how selective interventions can improve tissue perfusion and oxygen delivery during vascular disease.
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30
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Li L, He L, Wu D, Chen L, Jiang Z. Pannexin-1 channels and their emerging functions in cardiovascular diseases. Acta Biochim Biophys Sin (Shanghai) 2015; 47:391-6. [PMID: 25921414 DOI: 10.1093/abbs/gmv028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/04/2015] [Indexed: 11/15/2022] Open
Abstract
Pannexin-1, Pannexin-2, and Pannexin-3 are three members of the Pannexin family of channel-forming glycoprotein. Their primary function is defined by their ability to form single-membrane channels. Pannexin-1 ubiquitously exists in many cells and organs throughout the body and is specially distributed in the circulatory system, while the expressions of Pannexin-2 and Pannexin-3 are mostly restricted to organs and tissues. Pannexin-1 oligomers have been shown to be functional single membrane channels that connect intracellular and extracellular compartments and are not intercellular channels in appositional membranes. The physiological functions of Pannexin-1 are to link to the adenosine triphosphate efflux that acts as a paracrine signal, and regulate cellular inflammasomes in a variety of cell types under physiological and pathophysiological conditions. However, there are still many functions to be explored. This review summarizes recent reports and discusses the role of Pannexin-1 in cardiovascular diseases, including ischemia, arrhythmia, cardiac fibrosis, and hypertension. Pannexin-1 has been suggested as an exciting, clinically relevant target in cardiovascular diseases.
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Affiliation(s)
- Lanfang Li
- Post-doctoral Mobile Stations for Basic Medicine, Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang 421001, China Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Lu He
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Di Wu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Linxi Chen
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, University of South China, Hengyang 421001, China
| | - Zhisheng Jiang
- Post-doctoral Mobile Stations for Basic Medicine, Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang 421001, China
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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.
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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
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Straub AC, Zeigler AC, Isakson BE. The myoendothelial junction: connections that deliver the message. Physiology (Bethesda) 2015; 29:242-9. [PMID: 24985328 DOI: 10.1152/physiol.00042.2013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A vast amount of investigation has centered on how the endothelium and smooth muscle communicate. From this evidence, myoendothelial junctions have emerged as critical anatomical structures to regulate heterocellular cross talk. Indeed, there is now evidence that the myoendothelial junction serves as a signaling microdomain to organize proteins used to facilitate vascular heterocellular communication. This review highlights the evolving role of myoendothelial junctions in the context of vascular cell-cell communication.
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Affiliation(s)
- Adam C Straub
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Angela C Zeigler
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia; and
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia; and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
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Billaud M, Chiu YH, Lohman AW, Parpaite T, Butcher JT, Mutchler SM, DeLalio LJ, Artamonov MV, Sandilos JK, Best AK, Somlyo AV, Thompson RJ, Le TH, Ravichandran KS, Bayliss DA, Isakson BE. A molecular signature in the pannexin1 intracellular loop confers channel activation by the α1 adrenoreceptor in smooth muscle cells. Sci Signal 2015; 8:ra17. [PMID: 25690012 DOI: 10.1126/scisignal.2005824] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Both purinergic signaling through nucleotides such as ATP (adenosine 5'-triphosphate) and noradrenergic signaling through molecules such as norepinephrine regulate vascular tone and blood pressure. Pannexin1 (Panx1), which forms large-pore, ATP-releasing channels, is present in vascular smooth muscle cells in peripheral blood vessels and participates in noradrenergic responses. Using pharmacological approaches and mice conditionally lacking Panx1 in smooth muscle cells, we found that Panx1 contributed to vasoconstriction mediated by the α1 adrenoreceptor (α1AR), whereas vasoconstriction in response to serotonin or endothelin-1 was independent of Panx1. Analysis of the Panx1-deficient mice showed that Panx1 contributed to blood pressure regulation especially during the night cycle when sympathetic nervous activity is highest. Using mimetic peptides and site-directed mutagenesis, we identified a specific amino acid sequence in the Panx1 intracellular loop that is essential for activation by α1AR signaling. Collectively, these data describe a specific link between noradrenergic and purinergic signaling in blood pressure homeostasis.
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Affiliation(s)
- Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Thibaud Parpaite
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joshua T Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Stephanie M Mutchler
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mykhaylo V Artamonov
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joanna K Sandilos
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Angela K Best
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Avril V Somlyo
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Thu H Le
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA. Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA. Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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34
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Hayoz S, Bradley V, Boerman EM, Nourian Z, Segal SS, Jackson WF. Aging increases capacitance and spontaneous transient outward current amplitude of smooth muscle cells from murine superior epigastric arteries. Am J Physiol Heart Circ Physiol 2014; 306:H1512-24. [PMID: 24705555 DOI: 10.1152/ajpheart.00492.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Large conductance Ca(2+)-activated K(+) channels (BKCa) contribute to negative feedback regulation of smooth muscle cell (SMC) tone. However, the effects of aging on BKCa function are unclear. We tested the hypothesis that aging alters SMC BKCa function in superior epigastric arteries (SEAs) by using perforated patch recording of enzymatically isolated SMCs from 3- to 4-mo-old male C57BL/6 mice (Young) and 24- to 26-mo-old male C57BL/6 mice (Old). SMC capacitance from Young (15.7 ± 0.4 pF; n = 110) was less than Old (17.9 ± 0.5 pF; n = 104) (P < 0.05). SMCs displayed spontaneous transient outward currents (STOCs) at membrane potentials more positive than -30 mV; depolarization increased STOC amplitude and frequency (P < 0.05; n = 19-24). STOC frequency in Young (2.2 ± 0.6 Hz) was less than Old (4.2 ± 0.7 Hz) at -10 mV (P < 0.05, n = 27-30), with no difference in amplitude (1.0 ± 0.1 vs. 0.9 ± 0.1 pA/pF, respectively). At +30 mV, STOC amplitude in Young (3.2 ± 0.3 pA/pF) was less than Old (5.0 ± 0.5 pA/pF; P < 0.05, n = 61-67) with no difference in frequency (3.9 ± 0.4 vs. 3.2 ± 0.3 Hz, respectively). BKCa blockers (1 μM paxilline, 100 nM iberiotoxin, 1 mM tetraethylammonium) or a ryanodine receptor antagonist (100 μM tetracaine) inhibited STOCs (n ≥ 6; P < 0.05 each). Western blots revealed increased expression of BKCa α-subunit protein in Old. Pressure myography revealed no effect of age on SEA maximal diameter, myogenic tone, or paxilline-induced constriction (n = 10-12; P > 0.05). Enhanced functional expression of SMC BKCa-dependent STOCs in Old may represent an adaptation of resistance arteries to maintain functional integrity.
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Affiliation(s)
- Sebastien Hayoz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Vanessa Bradley
- College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
| | - Zahra Nourian
- Dalton Cardiovascular Research Center, Columbia, Missouri
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and Dalton Cardiovascular Research Center, Columbia, Missouri
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan;
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Westcott EB, Segal SS. Perivascular innervation: a multiplicity of roles in vasomotor control and myoendothelial signaling. Microcirculation 2013; 20:217-38. [PMID: 23289720 DOI: 10.1111/micc.12035] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/25/2012] [Indexed: 12/30/2022]
Abstract
The control of vascular resistance and tissue perfusion reflect coordinated changes in the diameter of feed arteries and the arteriolar networks they supply. Against a background of myogenic tone and metabolic demand, vasoactive signals originating from perivascular sympathetic and sensory nerves are integrated with endothelium-derived signals to produce vasodilation or vasoconstriction. PVNs release adrenergic, cholinergic, peptidergic, purinergic, and nitrergic neurotransmitters that lead to SMC contraction or relaxation via their actions on SMCs, ECs, or other PVNs. ECs release autacoids that can have opposing actions on SMCs. Respective cell layers are connected directly to each other through GJs at discrete sites via MEJs projecting through holes in the IEL. Whereas studies of intercellular communication in the vascular wall have centered on endothelium-derived signals that govern SMC relaxation, attention has increasingly focused on signaling from SMCs to ECs. Thus, via MEJs, neurotransmission from PVNs can evoke distinct responses from ECs subsequent to acting on SMCs. To integrate this emerging area of investigation in light of vasomotor control, the present review synthesizes current understanding of signaling events that originate within SMCs in response to perivascular neurotransmission in light of EC feedback. Although often ignored in studies of the resistance vasculature, PVNs are integral to blood flow control and can provide a physiological stimulus for myoendothelial communication. Greater understanding of these underlying signaling events and how they may be affected by aging and disease will provide new approaches for selective therapeutic interventions.
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Affiliation(s)
- Erika B Westcott
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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36
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Dora KA, Garland CJ. Linking hyperpolarization to endothelial cell calcium events in arterioles. Microcirculation 2013; 20:248-56. [PMID: 23311991 DOI: 10.1111/micc.12041] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/08/2013] [Indexed: 01/14/2023]
Abstract
Our understanding of the relationship between EC membrane potential and Ca(2+) entry has been shaped historically by data from cells in culture. Membrane hyperpolarization was associated with raised cytoplasmic [Ca(2+) ] ascribed to the increase in the inward electrochemical gradient for Ca(2+) , as ECs are generally thought to lack VGCC. Ca(2+) influx was assumed to reflect the presence of an undefined Ca(2+) "leak" channel, although the original research articles with isolated ECs did not elucidate which Ca(2+) influx channel was involved or indeed if a transporter might contribute. Overall, these early studies left many unanswered questions, not least whether a similar mechanism operates in native ECs that are coupled to each other and, in many smaller arteries and arterioles, to the adjacent vascular SMCs via gap junctions. This review discusses whether Ca(2+) leak through constitutively active EC Ca(2+) channels or a more defined, gated pathway might underlie the reported link between enhanced Ca(2+) entry and hyperpolarization. Electrophysiological evidence from ECs in isolation is compared with those in intact arteries and arterioles and the possible physiological relevance of EC Ca(2+) entry driven by hyperpolarization discussed.
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Affiliation(s)
- Kim A Dora
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.
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37
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Socha MJ, Domeier TL, Behringer EJ, Segal SS. Coordination of intercellular Ca(2+) signaling in endothelial cell tubes of mouse resistance arteries. Microcirculation 2013; 19:757-70. [PMID: 22860994 DOI: 10.1111/micc.12000] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 08/01/2012] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To test the hypothesis that Ca(2+) responses to GPCR activation are coordinated between neighboring ECs of resistance arteries. METHODS EC tubes were freshly isolated from superior epigastric arteries of C57BL/6 mice. Intercellular coupling was tested using microinjection of propidium iodide. Following loading with fluo-4 dye, intracellular Ca(2+) responses to ACh were imaged with confocal microscopy. RESULTS Cell-to-cell transfer of propidium iodide confirmed functional GJCs. A 1 μm ACh stimulus evoked Ca(2+) responses (9.8 ± 0.8/min, F/F(0) = 3.11 ± 0.2) which pseudo-line-scan analysis revealed as composed of Ca(2+) waves and spatially restricted Ca(2+) release events. A 100 nm ACh stimulus induced Ca(2+) responses of lower frequency (4.5 ± 0.7/min) and amplitude (F/F(0) = 1.95 ± 0.11) composed primarily of spatially restricted events. The time interval between Ca(2+) waves in adjacent cells (0.79 ± 0.12 s) was shorter (p < 0.05) than that between nonadjacent cells (1.56 ± 0.25 s). Spatially restricted Ca(2+) release events had similar frequencies and latencies between adjacent and nonadjacent cells. Inhibiting intracellular Ca(2+) release with 2-APB, Xestospongin C or thapsigargin eliminated Ca(2+) responses. CONCLUSIONS With moderate GPCR stimulation, localized Ca(2+) release events predominate among cells. Greater GPCR stimulation evokes coordinated intercellular Ca(2+) waves via the ER. Calcium signaling during GPCR activation is complex among cells, varying with stimulus intensity and proximity to actively signaling cells.
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Affiliation(s)
- Matthew J Socha
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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38
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Contribution of α-Adrenoceptor Stimulation by Phenylephrine to Basal Nitric Oxide Production in the Isolated Mouse Aorta. J Cardiovasc Pharmacol 2013; 61:318-23. [DOI: 10.1097/fjc.0b013e318281fa2d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nagaraja S, Kapela A, Tran CH, Welsh DG, Tsoukias NM. Role of microprojections in myoendothelial feedback--a theoretical study. J Physiol 2013; 591:2795-812. [PMID: 23529128 DOI: 10.1113/jphysiol.2012.248948] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated the role of myoendothelial projections (MPs) in endothelial cell (EC) feedback response to smooth muscle cell (SMC) stimulation using mathematical modelling. A previously developed compartmental EC-SMC model is modified to include MPs as subcellular compartments in the EC. The model is further extended into a 2D continuum model using a finite element method (FEM) approach and electron microscopy images to account for MP geometry. The EC and SMC are coupled via non-selective myoendothelial gap junctions (MEGJs) which are located on MPs and allow exchange of Ca(2+), K(+), Na(+) and Cl(-) ions and inositol 1,4,5-triphosphate (IP3). Models take into consideration recent evidence for co-localization of intermediate-conductance calcium-activated potassium channels (IKCa) and IP3 receptors (IP3Rs) in the MPs. SMC stimulation causes an IP3-mediated Ca(2+) transient in the MPs with limited global spread in the bulk EC. A hyperpolarizing feedback generated by the localized IKCa channels is transmitted to the SMC via MEGJs. MEGJ resistance (Rgj) and the density of IKCa and IP3R in the projection influence the extent of EC response to SMC stimulation. The predicted Ca(2+) transients depend also on the volume and geometry of the MP. We conclude that in the myoendothelial feedback response to SMC stimulation, MPs are required to amplify the SMC initiated signal. Simulations suggest that the signal is mediated by IP3 rather than Ca(2+) diffusion and that a localized rather than a global EC Ca(2+) mobilization is more likely following SMC stimulation.
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Affiliation(s)
- Sridevi Nagaraja
- Department of Biomedical Engineering, Florida International University, 10555 W. Flagler Street, EC 2674, Miami, FL 33174. USA
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Abstract
Beta-blockers are widely prescribed for the treatment of a variety of cardiovascular pathologies. Compared to traditional beta-adrenergic antagonists, beta-blockers of the new generation exhibit ancillary properties such as vasodilation through different mechanisms. This translates into a more favorable hemodynamic profile. The relative affinities of beta-adrenoreceptor antagonists towards the three beta-adrenoreceptor isotypes matter for predicting their functional impact on vasomotor control. This review will focus on the mechanisms underlying beta-blocker-evoked vasorelaxation with a specific emphasis on agonist properties of beta(3)-adrenergic receptors.
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Affiliation(s)
- Géraldine Rath
- Pole de Pharmacologie et Thérapeutique (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, B01.5309, Avenue Mounier 52, 1200, Brussels, Belgium.
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Looft-Wilson RC, Todd SE, Araj CA, Mutchler SM, Goodell CAR. Alpha(1)-adrenergic-mediated eNOS phosphorylation in intact arteries. Vascul Pharmacol 2012; 58:112-7. [PMID: 22982055 DOI: 10.1016/j.vph.2012.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 08/23/2012] [Accepted: 09/04/2012] [Indexed: 01/13/2023]
Abstract
Activation of arterial smooth muscle alpha(1)-adrenergic receptors results in vasoconstriction, as well as a secondary release of nitric oxide and slow vasodilation, presumably through gap junction communication from smooth muscle to endothelium. We hypothesized that this slow vasodilation is due to activation of eNOS through phosphorylation at Ser1179 and dephosphorylation at Thr495. Phosphorylation was measured by western blot using mouse mesenteric arteries that were cannulated and pressurized (75 mm Hg) and treated either by 1) 5 min of phenylephrine superfusion (10(-5)M) (PE5), 2) 15 min of phenylephrine (PE15), 3) 15 min phenylephrine followed by acetylcholine (10(-4)M) (PE+ACh), or 4) 20 min time control with no treatment (NT) [4-5 arteries pooled per treatment per blot; 5 blots performed]. These treatments allowed correlation between vasomotor changes, namely maximal constriction (PE5), slow vasodilation (PE15), and maximal dilation (PE+ACh), and relative phosphorylation changes. Phosphorylation of eNOS at Ser1179 was increased relative to NT by more than 2-fold at PE5 and remained similarly increased at PE15 and PE+ACh. Phosphorylation of eNOS at Thr495 was less in all treatments relative to NT, but not significantly. Treatment with L-NAME (10(-4)M) or endothelial denudation indicated that the slow dilation in response to phenylephrine was completely due to nitric oxide synthase and was endothelial dependent. These results indicate that eNOS phosphorylation at Ser1179 occurs before the slow dilation and is not actively involved in this vasodilation or dilation to acetylcholine, but may play a permissive role in eNOS activation by other mechanisms. It is not yet known what mechanism is responsible for Ser1179 phosphorylation with phenylephrine stimulation.
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Affiliation(s)
- Robin C Looft-Wilson
- Department of Kinesiology and Health Sciences, The College of William & Mary, Williamsburg, VA 23187, United States.
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Billaud M, Lohman AW, Straub AC, Parpaite T, Johnstone SR, Isakson BE. Characterization of the thoracodorsal artery: morphology and reactivity. Microcirculation 2012; 19:360-72. [PMID: 22335567 DOI: 10.1111/j.1549-8719.2012.00172.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES In this paper, we describe the histological and contractile properties of the thoracodorsal artery (TDA), which indirectly feeds the spinotrapezius muscle. METHODS We used immunolabelling techniques to histologically characterize the TDA while the contractile properties were assessed using pressure arteriography. RESULTS Our results demonstrate that the TDA is composed of approximately one to two layers of smooth muscle cells, is highly innervated with adrenergic nerves, and develops spontaneous tone at intraluminal pressures above 80 mmHg. The reactivity of the TDA in response to various contractile agonists such as phenylephrine, noradrenaline, angiotensin II, serotonin, endothelin 1, and ATP, as well as vasodilators, shows that the TDA exhibits a remarkably comparable reactivity to what has been observed in mesenteric arteries. We further studied the different components of the TDA response to acetylcholine, and found that the TDA was sensitive to TRAM 34, a blocker of the intermediate conductance potassium channel, which is highly suggestive of an endothelium-dependent hyperpolarization. CONCLUSIONS We conclude that the TDA exhibits comparable characteristics to other current vascular models, with the additional advantage of being easily manipulated for molecular and ex vivo vasoreactivity studies.
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Affiliation(s)
- Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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Abstract
Pannexins are a recently discovered protein family with the isoform Panx1 ubiquitously expressed and therefore extensively studied. Panx1 proteins form membrane channels known to release purines such as ATP. Because ATP and, more generally, purinergic signaling plays an important role in the vasculature, it became evident that Panx1 could have a key role in vascular functions. This article reviews recent findings on the pivotal role of Panx1 in smooth muscle cells in the contraction of arteries as well as recent insights into Panx1 channel regulation.
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Affiliation(s)
- Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
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Lohman AW, Billaud M, Isakson BE. Mechanisms of ATP release and signalling in the blood vessel wall. Cardiovasc Res 2012; 95:269-80. [PMID: 22678409 DOI: 10.1093/cvr/cvs187] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nucleotide adenosine 5'-triphosphate (ATP) has classically been considered the cell's primary energy currency. Importantly, a novel role for ATP as an extracellular autocrine and/or paracrine signalling molecule has evolved over the past century and extensive work has been conducted to characterize the ATP-sensitive purinergic receptors expressed on almost all cell types in the body. Extracellular ATP elicits potent effects on vascular cells to regulate blood vessel tone but can also be involved in vascular pathologies such as atherosclerosis. While the effects of purinergic signalling in the vasculature have been well documented, the mechanism(s) mediating the regulated release of ATP from cells in the blood vessel wall and circulation are now a key target of investigation. The aim of this review is to examine the current proposed mechanisms of ATP release from vascular cells, with a special emphasis on the transporters and channels involved in ATP release from vascular smooth muscle cells, endothelial cells, circulating red blood cells, and perivascular sympathetic nerves, including vesicular exocytosis, plasma membrane F(1)/F(0)-ATP synthase, ATP-binding cassette (ABC) transporters, connexin hemichannels, and pannexin channels.
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Affiliation(s)
- Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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45
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Westcott EB, Goodwin EL, Segal SS, Jackson WF. Function and expression of ryanodine receptors and inositol 1,4,5-trisphosphate receptors in smooth muscle cells of murine feed arteries and arterioles. J Physiol 2012; 590:1849-69. [PMID: 22331418 DOI: 10.1113/jphysiol.2011.222083] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We tested the hypothesis that vasomotor control is differentially regulated between feed arteries and downstream arterioles from the cremaster muscle of C57BL/6 mice. In isolated pressurized arteries, confocal Ca(2+) imaging of smooth muscle cells (SMCs) revealed Ca(2+) sparks and Ca(2+) waves. Ryanodine receptor (RyR) antagonists (ryanodine and tetracaine) inhibited both sparks and waves but increased global Ca(2+) and myogenic tone. In arterioles, SMCs exhibited only Ca(2+) waves that were insensitive to ryanodine or tetracaine. Pharmacological interventions indicated that RyRs are functionally coupled to large-conductance, Ca(2+)-activated K(+) channels (BK(Ca)) in SMCs of arteries, whereas BK(Ca) appear functionally coupled to voltage-gated Ca2+ channels in SMCs of arterioles. Inositol 1,4,5-trisphosphate receptor (IP3R) antagonists (xestospongin D or 2-aminoethoxydiphenyl borate) or a phospholipase C inhibitor (U73122) attenuated Ca(2+) waves, global Ca(2+) and myogenic tone in arteries and arterioles but had no effect on arterial sparks. Real-time PCR of isolated SMCs revealed RyR2 as the most abundant isoform transcript; arteries expressed twice the RyR2 but only 65% the RyR3 of arterioles and neither vessel expressed RyR1. Immunofluorescent localisation of RyR protein indicated bright, clustered staining of arterial SMCs in contrast to diffuse staining in arteriolar SMCs. Expression of IP(3)R transcripts and protein immunofluorescence were similar in SMCs of both vessels with IP(3)R1>>IP(3)R2>IP(3)R3. Despite similar expression of IP(3)Rs and dependence of Ca(2+) waves on IP(3)Rs, these data illustrate pronounced regional heterogeneity in function and expression of RyRs between SMCs of the same vascular resistance network. We conclude that vasomotor control is differentially regulated in feed arteries vs. downstream arterioles.
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Affiliation(s)
- Erika B Westcott
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA
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46
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Nausch LWM, Bonev AD, Heppner TJ, Tallini Y, Kotlikoff MI, Nelson MT. Sympathetic nerve stimulation induces local endothelial Ca2+ signals to oppose vasoconstriction of mouse mesenteric arteries. Am J Physiol Heart Circ Physiol 2012; 302:H594-602. [PMID: 22140050 PMCID: PMC3353782 DOI: 10.1152/ajpheart.00773.2011] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 11/28/2011] [Indexed: 12/18/2022]
Abstract
It is generally accepted that the endothelium regulates vascular tone independent of the activity of the sympathetic nervous system. Here, we tested the hypothesis that the activation of sympathetic nerves engages the endothelium to oppose vasoconstriction. Local inositol 1,4,5-trisphosphate (IP(3))-mediated Ca(2+) signals ("pulsars") in or near endothelial projections to vascular smooth muscle (VSM) were measured in an en face mouse mesenteric artery preparation. Electrical field stimulation of sympathetic nerves induced an increase in endothelial cell (EC) Ca(2+) pulsars, recruiting new pulsar sites without affecting activity at existing sites. This increase in Ca(2+) pulsars was blocked by bath application of the α-adrenergic receptor antagonist prazosin or by TTX but was unaffected by directly picospritzing the α-adrenergic receptor agonist phenylephrine onto the vascular endothelium, indicating that nerve-derived norepinephrine acted through α-adrenergic receptors on smooth muscle cells. Moreover, EC Ca(2+) signaling was not blocked by inhibitors of purinergic receptors, ryanodine receptors, or voltage-dependent Ca(2+) channels, suggesting a role for IP(3), rather than Ca(2+), in VSM-to-endothelium communication. Block of intermediate-conductance Ca(2+)-sensitive K(+) channels, which have been shown to colocalize with IP(3) receptors in endothelial projections to VSM, enhanced nerve-evoked constriction. Collectively, our results support the concept of a transcellular negative feedback module whereby sympathetic nerve stimulation elevates EC Ca(2+) signals to oppose vasoconstriction.
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MESH Headings
- Animals
- Calcium/metabolism
- Calcium Signaling/physiology
- Connexins/genetics
- Endothelium, Vascular/metabolism
- Feedback, Physiological/physiology
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Intermediate-Conductance Calcium-Activated Potassium Channels/metabolism
- Mesenteric Arteries/innervation
- Mesenteric Arteries/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle, Smooth, Vascular/metabolism
- Receptors, Adrenergic, alpha/metabolism
- Sympathetic Nervous System/physiology
- Vasoconstriction/physiology
- Gap Junction alpha-5 Protein
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Affiliation(s)
- Lydia W M Nausch
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, VT05405, USA.
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47
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Tran CHT, Taylor MS, Plane F, Nagaraja S, Tsoukias NM, Solodushko V, Vigmond EJ, Furstenhaupt T, Brigdan M, Welsh DG. Endothelial Ca2+ wavelets and the induction of myoendothelial feedback. Am J Physiol Cell Physiol 2012; 302:C1226-42. [PMID: 22277756 DOI: 10.1152/ajpcell.00418.2011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
When arteries constrict to agonists, the endothelium inversely responds, attenuating the initial vasomotor response. The basis of this feedback mechanism remains uncertain, although past studies suggest a key role for myoendothelial communication in the signaling process. The present study examined whether second messenger flux through myoendothelial gap junctions initiates a negative-feedback response in hamster retractor muscle feed arteries. We specifically hypothesized that when agonists elicit depolarization and a rise in second messenger concentration, inositol trisphosphate (IP(3)) flux activates a discrete pool of IP(3) receptors (IP(3)Rs), elicits localized endothelial Ca(2+) transients, and activates downstream effectors to moderate constriction. With use of integrated experimental techniques, this study provided three sets of supporting observations. Beginning at the functional level, we showed that blocking intermediate-conductance Ca(2+)-activated K(+) channels (IK) and Ca(2+) mobilization from the endoplasmic reticulum (ER) enhanced the contractile/electrical responsiveness of feed arteries to phenylephrine. Next, structural analysis confirmed that endothelial projections make contact with the overlying smooth muscle. These projections retained membranous ER networks, and IP(3)Rs and IK channels localized in or near this structure. Finally, Ca(2+) imaging revealed that phenylephrine induced discrete endothelial Ca(2+) events through IP(3)R activation. These events were termed recruitable Ca(2+) wavelets on the basis of their spatiotemporal characteristics. From these findings, we conclude that IP(3) flux across myoendothelial gap junctions is sufficient to induce focal Ca(2+) release from IP(3)Rs and activate a discrete pool of IK channels within or near endothelial projections. The resulting hyperpolarization feeds back on smooth muscle to moderate agonist-induced depolarization and constriction.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain and Libin Cardiovascular Research Institute, Department of Physiology and Pharmacology, University of Calgary, Canada
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48
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Al-Zobaidy MJ, Craig J, Brown K, Pettifor G, Martin W. Stimulus-specific blockade of nitric oxide-mediated dilatation by asymmetric dimethylarginine (ADMA) and monomethylarginine (L-NMMA) in rat aorta and carotid artery. Eur J Pharmacol 2011; 673:78-84. [PMID: 22056836 DOI: 10.1016/j.ejphar.2011.10.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 10/03/2011] [Accepted: 10/11/2011] [Indexed: 11/17/2022]
Abstract
Previous work on female rat aorta has shown that although monomethylarginine (L-NMMA) and asymmetric dimethylarginine (ADMA) each enhance submaximal phenylephrine-induced tone, consistent with blockade of basal nitric oxide activity, neither agent has any major effect on acetylcholine-induced relaxation. The aim of this study was to adopt a variety of different experimental approaches to test the hypothesis that these methylarginines block basal but not agonist-stimulated activity of nitric oxide. Basal activity of nitric oxide was assessed by observing the rise in submaximal phenylephrine-induced tone produced by nitric oxide synthase (NOS) inhibitors in male and female aorta and female carotid artery, and by monitoring the vasodilator actions of superoxide dismutase (SOD) or the PDE 5 inhibitor, T-0156. Agonist-stimulated activity of nitric oxide was assessed by observing the relaxant actions of acetylcholine or calcium ionophore A23187. L-NMMA, ADMA and L-NAME (100 μM) each enhanced submaximal phenylephrine-induced tone and inhibited SOD- or T-0156-induced relaxation, consistent with each NOS inhibitor blocking basal nitric oxide activity. In contrast, L-NMMA and ADMA had little effect on acetylcholine- or A23187-induced relaxation, while L-NAME produced powerful blockade. These observations provide support for the hypothesis that L-NMMA and ADMA selectively block basal over agonist-stimulated activity of nitric oxide in rat vessels.
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Affiliation(s)
- Mohammed J Al-Zobaidy
- College of Medical, Veterinary and Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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49
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Socha MJ, Hakim CH, Jackson WF, Segal SS. Temperature effects on morphological integrity and Ca²⁺ signaling in freshly isolated murine feed artery endothelial cell tubes. Am J Physiol Heart Circ Physiol 2011; 301:H773-83. [PMID: 21705671 DOI: 10.1152/ajpheart.00214.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To study Ca(2+) signaling in the endothelium of murine feed arteries, we determined the in vitro stability of endothelial cell (EC) tubes freshly isolated from abdominal muscle feed arteries of male and female C57BL/6 mice (5-9 mo, 25-35 g). We tested the hypothesis that intracellular Ca(2+) concentration ([Ca(2+)](i)) responses to muscarinic receptor activation would increase with temperature. Intact EC tubes (length: 1-2 mm, width: 65-80 μm) were isolated using gentle enzymatic digestion with trituration to remove smooth muscle cells. A freshly isolated EC tube was secured in a chamber and superfused at 24 (room temperature), 32, or 37°C. Using fura-2 dye, [Ca(2+)](i) was monitored (ratio of fluorescence at 340- to 380-nm wavelength) at rest and in response to bolus doses of ACh (20 nmol to 200 μmol). The morphological integrity of EC tubes was preserved at 24 and 32°C. Based on the Ca(2+) K(d) values we determined for fura-2 (174 nM at 24°C and 146 nM at 32°C), resting [Ca(2+)](i) remained stable for 180 min at both 24 and 32°C (27 ± 4 and 34 ± 2 nM, respectively), with peak responses to ACh (20 μmol) increasing from ∼220 nM at 24°C to ∼500 nM at 32°C (P < 0.05). There was no difference in responses to ACh between EC tubes from male versus female mice. When EC tubes were maintained at 37°C (typical in vivo temperature), resting [Ca(2+)](i) increased by ∼30% within 15 min, and gaps formed between individual ECs as they retracted and extruded dye, precluding further study. We conclude that EC tubes enable Ca(2+) signaling to be evaluated in the freshly isolated endothelium of murine feed arteries. While Ca(2+) responses are enhanced by approximately twofold at 32 versus 24°C, the instability of EC tubes at 37°C precludes their study at typical body temperature.
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Affiliation(s)
- Matthew J Socha
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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50
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Moore AW, Jackson WF, Segal SS. Regional heterogeneity of α-adrenoreceptor subtypes in arteriolar networks of mouse skeletal muscle. J Physiol 2011; 588:4261-74. [PMID: 20807785 DOI: 10.1113/jphysiol.2010.194993] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Activation of vascular adrenoreceptors (ARs) governs the magnitude and distribution of muscle blood flow in accord with the distribution of AR subtypes. Functional studies in the rat cremaster muscle indicate that α1ARs predominate in proximal arterioles (first-order, 1A) while α2ARs predominate in distal arterioles (third-order, 3A). However, little is known of AR subtype distribution in arteriolar networks of locomotor skeletal muscles, particularly in the mouse. We tested the hypotheses that functional AR subtypes exhibit heterogeneity among branches of arteriolar networks in a locomotor muscle and that the nature of this heterogeneity can vary between muscles having diverse functions. In anaesthetized male C57BL/6J mice (3 months old), concentration-response curves (10(-9) m to 10(-5) m, 0.5 log increments) were evaluated in the gluteus maximus muscle superfused with physiological saline solution (35°C, pH 7.4; n ≥ 5 per group). Noradrenaline (NA, non-selective αAR agonist) constricted 1A, 2A and 3A with similar potency and efficacy. Phenylephrine (PE; α1AR agonist) evoked greater (P < 0.05) constriction in 3A (inhibited by 10(-8) m prazosin; α1AR antagonist) while UK 14304 (UK; α2AR agonist) evoked greater (P < 0.05) constriction in 1A (inhibited by 10(-7) m rauwolscine; α2AR antagonist). Isoproterenol (isoprenaline; βAR agonist) dilated 1A, 2A and 3A near-maximally with similar potency and efficacy; these dilatations were inhibited by 10(-7) m propranolol (βAR antagonist) which otherwise had no effect on responses to NA, PE, or UK. Complementary experiments in the mouse cremaster muscle revealed a pattern of αAR subtype distribution that, while distinct from the gluteus maximus muscle, was consistent with that reported for the rat cremaster muscle. We conclude that functional αAR subtype distribution in arteriolar networks of skeletal muscle varies with muscle function as well as vessel branch order.
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Affiliation(s)
- Alex W Moore
- Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA
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