1
|
Bonilauri B, Dallagiovanna B. Microproteins in skeletal muscle: hidden keys in muscle physiology. J Cachexia Sarcopenia Muscle 2022; 13:100-113. [PMID: 34850602 PMCID: PMC8818594 DOI: 10.1002/jcsm.12866] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/01/2021] [Accepted: 10/12/2021] [Indexed: 11/10/2022] Open
Abstract
Recent advances in the transcriptomics, translatomics, and proteomics have led us to the exciting new world of functional endogenous microproteins. These microproteins have a small size and are derived from small open reading frames (smORFs) of RNAs previously annotated as non-coding (e.g. lncRNAs and circRNAs) as well as from untranslated regions and canonical mRNAs. The presence of these microproteins reveals a much larger translatable portion of the genome, shifting previously defined dogmas and paradigms. These findings affect our view of organisms as a whole, including skeletal muscle tissue. Emerging evidence demonstrates that several smORF-derived microproteins play crucial roles during muscle development (myogenesis), maintenance, and regeneration, as well as lipid and glucose metabolism and skeletal muscle bioenergetics. These microproteins are also involved in processes including physical activity capacity, cellular stress, and muscular-related diseases (i.e. myopathy, cachexia, atrophy, and muscle wasting). Given the role of these small proteins as important key regulators of several skeletal muscle processes, there are rich prospects for the discovery of new microproteins and possible therapies using synthetic microproteins.
Collapse
Affiliation(s)
- Bernardo Bonilauri
- Laboratory of Basic Biology of Stem Cells (LABCET)Carlos Chagas Institute ‐ Fiocruz‐PRCuritibaParanáBrazil
| | - Bruno Dallagiovanna
- Laboratory of Basic Biology of Stem Cells (LABCET)Carlos Chagas Institute ‐ Fiocruz‐PRCuritibaParanáBrazil
| |
Collapse
|
2
|
Ottolini M, Sonkusare SK. The Calcium Signaling Mechanisms in Arterial Smooth Muscle and Endothelial Cells. Compr Physiol 2021; 11:1831-1869. [PMID: 33792900 PMCID: PMC10388069 DOI: 10.1002/cphy.c200030] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The contractile state of resistance arteries and arterioles is a crucial determinant of blood pressure and blood flow. Physiological regulation of arterial contractility requires constant communication between endothelial and smooth muscle cells. Various Ca2+ signals and Ca2+ -sensitive targets ensure dynamic control of intercellular communications in the vascular wall. The functional effect of a Ca2+ signal on arterial contractility depends on the type of Ca2+ -sensitive target engaged by that signal. Recent studies using advanced imaging methods have identified the spatiotemporal signatures of individual Ca2+ signals that control arterial and arteriolar contractility. Broadly speaking, intracellular Ca2+ is increased by ion channels and transporters on the plasma membrane and endoplasmic reticular membrane. Physiological roles for many vascular Ca2+ signals have already been confirmed, while further investigation is needed for other Ca2+ signals. This article focuses on endothelial and smooth muscle Ca2+ signaling mechanisms in resistance arteries and arterioles. We discuss the Ca2+ entry pathways at the plasma membrane, Ca2+ release signals from the intracellular stores, the functional and physiological relevance of Ca2+ signals, and their regulatory mechanisms. Finally, we describe the contribution of abnormal endothelial and smooth muscle Ca2+ signals to the pathogenesis of vascular disorders. © 2021 American Physiological Society. Compr Physiol 11:1831-1869, 2021.
Collapse
Affiliation(s)
- Matteo Ottolini
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Swapnil K Sonkusare
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA.,Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
| |
Collapse
|
3
|
Fransen P, Chen J, Vangheluwe P, Guns PJ. Contractile Behavior of Mouse Aorta Depends on SERCA2 Isoform Distribution: Effects of Replacing SERCA2a by SERCA2b. Front Physiol 2020; 11:282. [PMID: 32296344 PMCID: PMC7136392 DOI: 10.3389/fphys.2020.00282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/12/2020] [Indexed: 01/16/2023] Open
Abstract
The Sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) actively pumps Ca2+ into the sarco/endoplasmic reticulum, thereby regulating intracellular Ca2+ concentrations and associated physiological processes. Different SERCA isoforms have been described (SERCA1, 2, and 3) with SERCA2 playing a pivotal role in Ca2+ homeostasis in cardiovascular tissues. In the heart, SERCA2a is the dominant isoform and has been proposed as therapeutic target in patients with heart failure. In the vasculature, both SERCA2a and SERCA2b are expressed with SERCA2b being the predominant isoform. The physiological role of SERCA2a in the vasculature, however, remains incompletely understood. In the present study, we used gene-modified mice in which the alternative splicing of the SERCA2-encoding gene (Atp2a2), underlying the expression of SERCA2a, is prevented and SERCA2a is replaced by SERCA2b. The resulting SERCA2b/b mice provide a unique opportunity to investigate the specific contribution of SERCA2a versus SERCA2b to vascular physiology. Aortic segments of SERCA2b/b (SERCA2a-deficient) and SERCA2a/b (control) mice were mounted in organ baths to evaluate vascular reactivity. SERCA2b/b aortic rings displayed higher contractions induced by phenylephrine (1 μM). Surprisingly, the initial inositol-3-phosphate mediated phasic contraction showed a faster decay of force in SERCA2b/b mice, while the subsequent tonic contraction was larger in SERCA2b/b segments. Moreover, in the presence of the calcium channel blocker diltiazem (35 μM) SERCA2b/b aortic rings showed higher contractions compared to SERCA2a/b, suggesting that SERCA2a (deficiency) modulates the activity of non-selective cation channels. Additionally, in endothelial cell (EC)-denuded aortic segments, the SERCA-inhibitor cyclopiazonic acid (CPA) caused markedly larger contractions in SERCA2b/b mice, while the increases of cytosolic Ca2+ were similar in both strains. Hence, aortas of SERCA2b/b mice appear to have a stronger coupling of intracellular Ca2+ to contraction, which may be in agreement with the reported difference in intracellular localization of SERCA2a versus SERCA2b. Finally, EC-mediated relaxation by acetylcholine and ATP was assessed. Concentration-response-curves for ATP showed a higher sensitivity of aortic segments of SERCA2b/b mice, while no difference in potency between strains were observed for acetylcholine. In summary, despite the relative low expression of SERCA2a in the murine aorta, our results point toward a distinct role in vascular physiology.
Collapse
Affiliation(s)
- Paul Fransen
- Laboratory of Physiopharmacology, Faculty of Pharmaceutical Sciences and Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jialin Chen
- Laboratory of Cellular Transport Systems, KU Leuven, Leuven, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, KU Leuven, Leuven, Belgium
| | - Pieter-Jan Guns
- Laboratory of Physiopharmacology, Faculty of Pharmaceutical Sciences and Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| |
Collapse
|
4
|
Keeley TP, Siow RCM, Jacob R, Mann GE. Reduced SERCA activity underlies dysregulation of Ca 2+ homeostasis under atmospheric O 2 levels. FASEB J 2017; 32:2531-2538. [PMID: 29273673 PMCID: PMC5901376 DOI: 10.1096/fj.201700685rrr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Unregulated increases in cellular Ca2+ homeostasis are a hallmark of pathophysiological conditions and a key trigger of cell death. Endothelial cells cultured under physiologic O2 conditions (5% O2) exhibit a reduced cytosolic Ca2+ response to stimulation. The mechanism for reduced plateau [Ca2+]i upon stimulation was due to increased sarco/endoplasmic reticulum Ca2+ ATPase (SERCA)-mediated reuptake rather than changes in Ca2+ influx capacity. Agonist-stimulated phosphorylation of the SERCA regulatory protein phospholamban was increased in cells cultured under 5% O2. Elevation of cytosolic and mitochondrial [Ca2+] and cell death after prolonged ionomycin treatment, as a model of Ca2+ overload, were lower when cells were cultured long-term under 5% compared with 18% O2. This protection was abolished by cotreatment with the SERCA inhibitor cyclopiazonic acid. Taken together, these results demonstrate that culturing cells under hyperoxic conditions reduces their ability to efficiently regulate [Ca2+]i, resulting in greater sensitivity to cytotoxic stimuli.-Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. Reduced SERCA activity underlies dysregulation of Ca2+ homeostasis under atmospheric O2 levels.
Collapse
Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Richard C M Siow
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Ron Jacob
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| |
Collapse
|
5
|
Anderson DM, Makarewich CA, Anderson KM, Shelton JM, Bezprozvannaya S, Bassel-Duby R, Olson EN. Widespread control of calcium signaling by a family of SERCA-inhibiting micropeptides. Sci Signal 2016; 9:ra119. [PMID: 27923914 DOI: 10.1126/scisignal.aaj1460] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Micropeptides function as master regulators of calcium-dependent signaling in muscle. Sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), the membrane pump that promotes muscle relaxation by taking up Ca2+ into the sarcoplasmic reticulum, is directly inhibited by three muscle-specific micropeptides: myoregulin (MLN), phospholamban (PLN), and sarcolipin (SLN). The widespread and essential function of SERCA across diverse cell types has raised questions as to how SERCA is regulated in cells that lack MLN, PLN, and SLN. We identified two transmembrane micropeptides, endoregulin (ELN) and another-regulin (ALN), that share key amino acids with their muscle-specific counterparts and function as direct inhibitors of SERCA pump activity. The distribution of transcripts encoding ELN and ALN mirrored that of SERCA isoform-encoding transcripts in nonmuscle cell types. Our findings identify additional members of the SERCA-inhibitory micropeptide family, revealing a conserved mechanism for the control of intracellular Ca2+ dynamics in both muscle and nonmuscle cell types.
Collapse
Affiliation(s)
- Douglas M Anderson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA. .,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Catherine A Makarewich
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Kelly M Anderson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - John M Shelton
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Svetlana Bezprozvannaya
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA. .,Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| |
Collapse
|
6
|
Grover AK. Sodium-Calcium Exchanger in Pig Coronary Artery. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:145-170. [PMID: 28212796 DOI: 10.1016/bs.apha.2016.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review focuses on the sodium-calcium exchangers (NCX) in the left anterior descending coronary artery smooth muscle. Bathing tissues in Na+-substituted solutions caused them to contract. In cultured smooth muscle cells, it increased the cytosolic Ca2+ concentration and extracellular entry of 45Ca2+. All three activities were attributed to NCX since they were inhibited by NCX inhibitors. The tissues also expressed the sarco/endoplasmic reticulum (SER) Ca2+ pump SERCA2b whose activity was much greater than that of NCX. Inhibiting SERCA2b with thapsigargin decreased the NCX-mediated 45Ca2+ accumulation by the cells. The decrease was not observed in cells loaded with the Ca2+-chelator BAPTA. The results are consistent with a limited diffusional space model with a proximity between NCX and SERCA2b. NCX molecules appear to be colocalized with the subsarcolemmal SERCA2b based on studies on membrane flotation experiments and microscopic fluorescence imaging of antibody-labeled cells. Thapsigargin inhibition of SERCA2b moved NCX even closer to SER. This provides a model for the NCX-mediated Ca2+ refilling of SER in the arterial smooth muscle. The model for the NCX-mediated refilling of the depleted SER proposed for smooth muscle did not apply to endothelium in which NCX levels were greater and SERCA levels were lower than in smooth muscle. The effect of thapsigargin on the NCX-mediated Ca2+ accumulation which was observed in smooth muscle was absent in the endothelium. We propose that the coupling between NCX and smooth muscle may be tissue dependent.
Collapse
Affiliation(s)
- A K Grover
- McMaster University, Hamilton, ON, Canada.
| |
Collapse
|
7
|
Bálint Z, Zabini D, Konya V, Nagaraj C, Végh AG, Váró G, Wilhelm I, Fazakas C, Krizbai IA, Heinemann A, Olschewski H, Olschewski A. Double-stranded RNA attenuates the barrier function of human pulmonary artery endothelial cells. PLoS One 2013; 8:e63776. [PMID: 23755110 PMCID: PMC3670875 DOI: 10.1371/journal.pone.0063776] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/05/2013] [Indexed: 11/18/2022] Open
Abstract
Circulating RNA may result from excessive cell damage or acute viral infection and can interact with vascular endothelial cells. Despite the obvious clinical implications associated with the presence of circulating RNA, its pathological effects on endothelial cells and the governing molecular mechanisms are still not fully elucidated. We analyzed the effects of double stranded RNA on primary human pulmonary artery endothelial cells (hPAECs). The effect of natural and synthetic double-stranded RNA (dsRNA) on hPAECs was investigated using trans-endothelial electric resistance, molecule trafficking, calcium (Ca2+) homeostasis, gene expression and proliferation studies. Furthermore, the morphology and mechanical changes of the cells caused by synthetic dsRNA was followed by in-situ atomic force microscopy, by vascular-endothelial cadherin and F-actin staining. Our results indicated that exposure of hPAECs to synthetic dsRNA led to functional deficits. This was reflected by morphological and mechanical changes and an increase in the permeability of the endothelial monolayer. hPAECs treated with synthetic dsRNA accumulated in the G1 phase of the cell cycle. Additionally, the proliferation rate of the cells in the presence of synthetic dsRNA was significantly decreased. Furthermore, we found that natural and synthetic dsRNA modulated Ca2+ signaling in hPAECs by inhibiting the sarco-endoplasmic Ca2+-ATPase (SERCA) which is involved in the regulation of the intracellular Ca2+ homeostasis and thus cell growth. Even upon synthetic dsRNA stimulation silencing of SERCA3 preserved the endothelial monolayer integrity. Our data identify novel mechanisms by which dsRNA can disrupt endothelial barrier function and these may be relevant in inflammatory processes.
Collapse
Affiliation(s)
- Zoltán Bálint
- Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Diana Zabini
- Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Viktoria Konya
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Chandran Nagaraj
- Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Attila G. Végh
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - György Váró
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Imola Wilhelm
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Csilla Fazakas
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - István A. Krizbai
- Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Akos Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Horst Olschewski
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Andrea Olschewski
- Experimental Anesthesiology, Department of Anesthesia and Intensive Care Medicine, Medical University of Graz, Graz, Austria
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
- * E-mail:
| |
Collapse
|
8
|
Evangelista AM, Thompson MD, Weisbrod RM, Pimental DR, Tong X, Bolotina VM, Cohen RA. Redox regulation of SERCA2 is required for vascular endothelial growth factor-induced signaling and endothelial cell migration. Antioxid Redox Signal 2012; 17:1099-108. [PMID: 22472004 PMCID: PMC3423867 DOI: 10.1089/ars.2011.4022] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AIMS Vascular endothelial growth factor (VEGF) increases angiogenesis by stimulating endothelial cell (EC) migration. VEGF-induced nitric oxide ((•)NO) release from (•)NO synthase plays a critical role, but the proteins and signaling pathways that may be redox-regulated are poorly understood. The aim of this work was to define the role of (•)NO-mediated redox regulation of the sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) in VEGF-induced signaling and EC migration. RESULTS VEGF-induced EC migration was prevented by the (•)NO synthase inhibitor, N (G)-nitro-L-arginine methyl ester (LNAME). Either VEGF or (•)NO stimulated endoplasmic reticulum (ER) (45)Ca(2+) uptake, a measure of SERCA activity, and knockdown of SERCA2 prevented VEGF-induced EC migration and (45)Ca(2+) uptake. S-glutathione adducts on SERCA2b, identified immunochemically, were increased by VEGF, and were prevented by LNAME or overexpression of glutaredoxin-1 (Glrx-1). Furthermore, VEGF failed to stimulate migration of ECs overexpressing Glrx-1. VEGF or (•)NO increased SERCA S-glutathiolation and stimulated migration of ECs in which wild-type (WT) SERCA2b was overexpressed with an adenovirus, but did neither in those overexpressing a C674S SERCA2b mutant, in which the reactive cysteine-674 was mutated to a serine. Increased EC Ca(2+) influx caused by VEGF or (•)NO was abrogated by overexpression of Glrx-1 or the C674S SERCA2b mutant. ER store-emptying through the ryanodine receptor (RyR) and Ca(2+) entry through Orai1 were also required for VEGF- and (•)NO-induced EC Ca(2+) influx. INNOVATION AND CONCLUSIONS These results demonstrate that (•)NO-mediated activation of SERCA2b via S-glutathiolation of cysteine-674 is required for VEGF-induced EC Ca(2+) influx and migration, and establish redox regulation of SERCA2b as a key component in angiogenic signaling.
Collapse
Affiliation(s)
- Alicia M Evangelista
- Vascular Biology Section, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | | | | | | | | | | |
Collapse
|
9
|
Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
Collapse
Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
| | | | | |
Collapse
|
10
|
Bobe R, Bredoux R, Corvazier E, Lacabaratz-Porret C, Martin V, Kovács T, Enouf J. How many Ca2+ATPase isoforms are expressed in a cell type? A growing family of membrane proteins illustrated by studies in platelets. Platelets 2009; 16:133-50. [PMID: 16011958 DOI: 10.1080/09537100400016847] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ca(2+) signaling plays a key role in normal and abnormal platelet functions. Understanding platelet Ca(2+) signaling requires the knowledge of proteins involved in this process. Among these proteins are Ca(2+)ATPases or Ca(2+) pumps that deplete the cytosol of Ca(2+) ions. Here, we will particularly focus on two Ca(2+) pump families: the plasma membrane Ca(2+)ATPases (PMCAs) that extrude cytosolic Ca(2+) towards the extracellular medium and the sarco/endoplasmic reticulum Ca(2+)ATPases (SERCAs) that pump Ca(2+) into the endoplasmic reticulum (ER). In the present review, we will summarize data on platelet Ca(2+)ATPases including their identification and biogenesis. First of all, we will present the Ca(2+)ATPase genes and their isoforms expressed in platelets. We will especially focus on a member of the SERCA family, SERCA3, recently found to give rise to a number of species-specific isoforms. Next, we will describe the differences in Ca(2+)ATPase patterns observed in human and rat platelets. Last, we will analyze how the expression of Ca(2+)ATPase isoforms changes during megakaryocytic maturation and show that megakaryocytopoiesis is associated with a profound reorganization of the expression and/or activity of Ca(2+)ATPases. Taken together, these data provide new aspects of investigations to better understand normal and abnormal platelet Ca(2+) signaling.
Collapse
Affiliation(s)
- R Bobe
- INSERM U.689 E6, IFR139 Lariboisière, Hôpital Lariboisière, 8 Rue Guy Patin, 75475 Paris Cedex 10, France
| | | | | | | | | | | | | |
Collapse
|
11
|
Davis KA, Samson SE, Hammel KE, Kiss L, Fulop F, Grover AK. Functional linkage of Na+-Ca2+-exchanger to sarco/endoplasmic reticulum Ca2+ pump in coronary artery: comparison of smooth muscle and endothelial cells. J Cell Mol Med 2008; 13:1775-1783. [PMID: 18752635 DOI: 10.1111/j.1582-4934.2008.00480.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
An increase in cytosolic Ca(2+) concentration in coronary artery smooth muscle causes a contraction but in endothelium it causes relaxation. Na(+)-Ca(2+)-exchanger (NCX) may play a role in Ca(2+) dynamics in both the cell types. Here, the NCX-mediated (45)Ca(2+) uptake was compared in Na(+)-loaded pig coronary artery smooth muscle and endothelial cells. In both the cell types, this uptake was inhibited by KB-R7943, SEA 0400 and by monensin, but not by cariporide. Prior loading of the cells with the Ca(2+) chelator BAPTA increased the NCX-mediated (45)Ca(2+) uptake in smooth muscle but not in endothelial cells. In the presence or absence of BAPTA loading, the Na(+)-mediated (45)Ca(2+) uptake was greater in endothelial than in smooth muscle cells. In smooth muscle cells without BAPTA loading, thapsigargin diminished the NCX-mediated (45)Ca(2+) entry. This effect was not observed in endothelial cells or in either cell type after BAPTA loading. The results in the smooth muscle cells are consistent with a limited diffusional space model in which the NCX-mediated (45)Ca(2+) uptake was enhanced by chelation of cytosolic Ca(2+) or by its sequestration by the sarco/endoplasmic reticulum Ca(2+) pump (SERCA). They suggest a functional linkage between NCX and SERCA in the smooth muscle but not in the endothelial cells. The concept of a linkage between NCX and SERCA in smooth muscle was also confirmed by similar distribution of NCX and SERCA2 proteins when detergent-treated microsomes were fractionated by flotation on sucrose density gradients. Thus, the coronary artery smooth muscle and endothelial cells differ not only in the relative activities of NCX but also in its functional linkage to SERCA.
Collapse
Affiliation(s)
- Kim A Davis
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Sue E Samson
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Kaitlin E Hammel
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Lorand Kiss
- Institute of Pharmaceutical Chemistry, University of Szeged, Szeged, Eotvo, Hungary
| | - Ferenc Fulop
- Institute of Pharmaceutical Chemistry, University of Szeged, Szeged, Eotvo, Hungary
| | - Ashok K Grover
- Department of Biology, McMaster University, Hamilton, Ontario, Canada.,Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
12
|
Szewczyk MM, Davis KA, Samson SE, Simpson F, Rangachari PK, Grover AK. Ca2+-pumps and Na2+-Ca2+-exchangers in coronary artery endothelium versus smooth muscle. J Cell Mol Med 2007; 11:129-38. [PMID: 17367507 PMCID: PMC4401226 DOI: 10.1111/j.1582-4934.2007.00010.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Vascular endothelial cells (EC) and smooth muscle cells (SMC) require a decrease in cytoplasmic Ca2+ concentration after activation. This can be achieved by Ca2+ sequestration by the sarco-/endoplasmic reticulum Ca2+ pumps (SERCA) and Ca2+ extrusion by plasma membrane Ca2+ pumps (PMCA) and Na+–Ca2+-exchangers (NCX). Since the two cell types differ in their structure and function, we compared the activities of PMCA, NCX and SERCA in pig coronary artery EC and SMC, the types of isoforms expressed using RT-PCR, and their protein abundance using Western blots. The activity of NCX is higher in EC than in SMC but those of PMCA and SERCA is lower. Consistently, the protein abundance for NCX protein is higher in EC than in SMC and those of PMCA and SERCA is lower. Based on RT-PCR experiments, the types of RNA present are as follows: EC for PMCA1 while SMC for PMCA4 and PMCA1; EC for SERCA2 and SERCA3 and SMC for SERCA2. Both EC and SMC express NCX1 (mainly NCX1.3). PMCA, SERCA and NCX differ in their affinities for Ca2+ and regulation. Based on these observations and the literature, we conclude that the tightly regulated Ca2+ removal systems in SMC are consistent with the cyclical control of contractility of the filaments and those in EC are consistent with Ca2+ regulation of the endothelial nitric oxide synthase near the cell surface. The differences between EC and SMC should be considered in therapeutic interventions of cardiovascular diseases.
Collapse
Affiliation(s)
- Magdalena M Szewczyk
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- *Correspondence to Dr A.K. GROVER Department of Medicine, HSC 4N41, McMaster University, 1200 Main Street West Hamilton, Ontario L8N 3Z5 Canada. Tel.: 905-525-9140 x22238 Fax: 905-522-3114 E-mail:
| | - Kim A Davis
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Sue E Samson
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Fiona Simpson
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | - Ashok K Grover
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- *Correspondence to Dr A.K. GROVER Department of Medicine, HSC 4N41, McMaster University, 1200 Main Street West Hamilton, Ontario L8N 3Z5 Canada. Tel.: 905-525-9140 x22238 Fax: 905-522-3114 E-mail:
| |
Collapse
|
13
|
Misquitta CM, Chen T, Grover AK. Control of protein expression through mRNA stability in calcium signalling. Cell Calcium 2006; 40:329-46. [PMID: 16765440 DOI: 10.1016/j.ceca.2006.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 03/22/2006] [Accepted: 04/12/2006] [Indexed: 01/14/2023]
Abstract
Specific sequences (cis-acting elements) in the 3'-untranslated region (UTR) of RNA, together with stabilizing and destabilizing proteins (trans-acting factors), determine the mRNA stability, and consequently, the level of expression of several proteins. Such interactions were discovered initially for short-lived mRNAs encoding cytokines and early genes like c-jun and c-myc. However, they may also determine the fate of more stable mRNAs in a tissue and disease-dependent manner. The interactions between the cis-acting elements and the trans-acting factors may also be modulated by Ca(2+) either directly or via a control of the phosphorylation status of the trans-acting factors. We focus initially on the basic concepts in mRNA stability with the trans-acting factors AUF1 (destabilizing) and HuR (stabilizing). Sarco/endoplasmic reticulum Ca(2+) pumps, SERCA2a (cardiac and slow twitch muscles) and SERCA2b (most cells including smooth muscle cells), are pivotal in Ca(2+) mobilization during signal transduction. SERCA2a and SERCA2b proteins are encoded by relatively stable mRNAs that contain cis-acting stability determinants in their 3'-regions. We present several pathways where 3'-UTR mediated mRNA decay is key to Ca(2+) signalling: SERCA2a and beta-adrenergic receptors in heart failure, renin-angiotensin system, and parathyroid hormones. Other examples discussed include cytokines vascular endothelial growth factor, endothelin and endothelial nitric oxide synthase. Roles of Ca(2+) and Ca(2+)-binding proteins in mRNA stability are also discussed. We anticipate that these novel modes of control of protein expression will form an emerging area of research that may explore the central role of Ca(2+) in cell function during development and in disease.
Collapse
Affiliation(s)
- Christine M Misquitta
- Banting and Best Department of Medical Research, 10th floor Donnelly CCBR, University of Toronto, 160 College Street, Toronto, Ont., Canada M5S 3E1
| | | | | |
Collapse
|
14
|
Thorneloe KS, Nelson MT. Ion channels in smooth muscle: regulators of intracellular calcium and contractility. Can J Physiol Pharmacol 2005; 83:215-42. [PMID: 15870837 DOI: 10.1139/y05-016] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Smooth muscle (SM) is essential to all aspects of human physiology and, therefore, key to the maintenance of life. Ion channels expressed within SM cells regulate the membrane potential, intracellular Ca2+ concentration, and contractility of SM. Excitatory ion channels function to depolarize the membrane potential. These include nonselective cation channels that allow Na+ and Ca2+ to permeate into SM cells. The nonselective cation channel family includes tonically active channels (Icat), as well as channels activated by agonists, pressure-stretch, and intracellular Ca2+ store depletion. Cl--selective channels, activated by intracellular Ca2+ or stretch, also mediate SM depolarization. Plasma membrane depolarization in SM activates voltage-dependent Ca2+ channels that demonstrate a high Ca2+ selectivity and provide influx of contractile Ca2+. Ca2+ is also released from SM intracellular Ca2+ stores of the sarcoplasmic reticulum (SR) through ryanodine and inositol trisphosphate receptor Ca2+ channels. This is part of a negative feedback mechanism limiting contraction that occurs by the Ca2+-dependent activation of large-conductance K+ channels, which hyper polarize the plasma membrane. Unlike the well-defined contractile role of SR-released Ca2+ in skeletal and cardiac muscle, the literature suggests that in SM Ca2+ released from the SR functions to limit contractility. Depolarization-activated K+ chan nels, ATP-sensitive K+ channels, and inward rectifier K+ channels also hyperpolarize SM, favouring relaxation. The expression pattern, density, and biophysical properties of ion channels vary among SM types and are key determinants of electrical activity, contractility, and SM function.
Collapse
Affiliation(s)
- Kevin S Thorneloe
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington 05405, USA.
| | | |
Collapse
|
15
|
Best KA, Holmes ME, Samson SE, Mwanjewe J, Wilson JX, Dixon SJ, Grover AK. Ascorbate uptake in pig coronary artery endothelial cells. Mol Cell Biochem 2005; 271:43-9. [PMID: 15881654 DOI: 10.1007/s11010-005-3442-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Although smooth muscle and endothelial cells in pig coronary artery are morphologically and functionally distinct, ascorbate uptake has been characterized only in smooth muscle cells. Ascorbate transporters in kidney and intestinal epithelial cells differ from those in smooth muscle. We examined ascorbate transport and mRNA expression of sodium-dependent vitamin C transporters (SVCT) by RT-PCR in the pig coronary artery endothelial cell cultures. When 14C-ascorbate uptake in endothelial cells was examined as 14C or by HPLC, the two values did not differ from each other. 14C-ascorbate uptake was Na(+)-dependent, stereoselective for L-ascorbate and inhibited by sulfinpyrazone. The kinetic characteristics of the uptake were: Km = 27 +/- 3 microM (Hill coefficient = 1) for ascorbate and Km = 73 +/- 14 mM (Hill coefficient = 2) for Na+. Surprisingly, endothelial cells had similar kinetic parameters as smooth muscle cells, except for a slightly lower uptake velocity in endothelial cells. Comparison with the smooth muscle showed that both tissue types expressed mRNA for SVCT2. Endothelial cells differ from epithelial cells which express mainly SVCT1 but resemble smooth muscle cells in this respect.
Collapse
Affiliation(s)
- Kelly A Best
- Department of Biology, McMaster University, Hamilton Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
16
|
Schmidt T, Zaib F, Samson SE, Kwan CY, Grover AK. Peroxynitrite resistance of sarco/endoplasmic reticulum Ca2+ pump in pig coronary artery endothelium and smooth muscle. Cell Calcium 2004; 36:77-82. [PMID: 15126058 DOI: 10.1016/j.ceca.2003.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 12/02/2003] [Accepted: 12/15/2003] [Indexed: 11/20/2022]
Abstract
We examined the effects of peroxynitrite pre-treatment on sarco/endoplasmic reticulum Ca(2+) (SERCA) pump in pig coronary artery smooth muscle and endothelium. In saponin-permeabilized cells, smooth muscle showed much greater rates of the SERCA Ca(2+) pump-dependent (45)Ca(2+) uptake/mg protein than did the endothelial cells. Peroxynitrite treatment of cells inhibited the SERCA pump more severely in smooth muscle cells than in endothelial cells. To determine implications of this observation, we next examined the effect of the SERCA pump inhibitor cyclopiazonic acid (CPA) on intracellular Ca(2+) concentration of intact cultured cells. CPA produced cytosolic Ca(2+) transients in cultured endothelial and smooth muscle cells. Pre-treatment with peroxynitrite (200 microM) inhibited the Ca(2+) transients in the smooth muscle but not in the endothelial cells. CPA contracts de-endothelialized artery rings and relaxes precontracted arteries with intact endothelium. Peroxynitrite (250 microM) pre-treatment inhibited contraction in the de-endothelialized artery rings, but not the endothelium-dependent relaxation. Thus, endothelial cells appear to be more resistant than smooth muscle to the effects of peroxynitrite at the levels of SERCA pump activity, CPA-induced Ca(2+) transients in cultured cells, and the effects of CPA on contractility. The greater resistance of endothelium to peroxynitrite may play a protective role in pathological conditions such as ischemia-reperfusion when excess free radicals are produced.
Collapse
Affiliation(s)
- Tracey Schmidt
- Department of Medicine, McMaster University, Hamilton, Ont., Canada L8N3Z5
| | | | | | | | | |
Collapse
|
17
|
Grover AK, Kwan CY, Samson SE. Effects of peroxynitrite on sarco/endoplasmic reticulum Ca2+ pump isoforms SERCA2b and SERCA3a. Am J Physiol Cell Physiol 2004; 285:C1537-43. [PMID: 14600079 DOI: 10.1152/ajpcell.00299.2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sarco(endo)plasmic reticulum Ca2+ (SERCA) pumps are important for cell signaling. Three different genes, SERCA1, 2, and 3, encode these pumps. Most tissues, including vascular smooth muscle, express a splice variant of SERCA2 (SERCA2b), whereas SERCA3a is widely distributed in tissues such as vascular endothelium, tracheal epithelium, mast cells, and lymphoid cells. SERCA2b protein is readily inactivated by peroxynitrite that may be formed during cardiac ischemia reperfusion or during immune response after infection. Here, we compared the peroxynitrite sensitivity of SERCA2b and SERCA3a by using microsomes prepared from HEK-293T cells overexpressing the pumps. We incubated the microsomes with different concentrations of peroxynitrite and determined Ca2+ uptake, Ca2+-Mg2+-ATPase, Ca2+-dependent formation of acylphosphate intermediate, and protein mobility in Western blots. Ca2+ uptake, Ca2+-Mg2+-ATPase, and Ca2+-dependent formation of acylphosphate intermediate were inactivated for both SERCA2b and SERCA3a, but the latter was more resistant to the inactivation. Western blots showed that SERCA2b and SERCA3a proteins oligomerized after treatment with peroxynitrite, but each with a slightly different pattern. Compared with monomers, the oligomers may be less efficient in forming the acylphosphate intermediate and in conducting the remainder of the steps in the reaction cycle. We conclude that the resistance of SERCA3a to peroxynitrite may aid the cells expressing them in functioning during exposure to oxidative stress.
Collapse
Affiliation(s)
- Ashok K Grover
- Dept. of Medicine, HSC 4N41, McMaster Univ., 1200 Main St. West, Hamilton, Ontario L8N 3Z5 Canada.
| | | | | |
Collapse
|
18
|
Halford C, Samson SE, Kwan CY, Grover AK. Endothelium and smooth muscle of pig coronary artery: differences in metabolism. Mol Cell Biochem 2003; 250:197-201. [PMID: 12962158 DOI: 10.1023/a:1024942526849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Here, we report that the smooth muscle and endothelium of the pig coronary artery differ in the profiles of energy metabolism nucleotides. ATP levels in the freshly isolated smooth muscle (1490 +/- 93, all the values are in pmol/mg protein) were significantly greater than in the endothelium (418 +/- 68). In contrast, endothelium contained higher levels of NADH (328 +/- 21), NAD+ (1210 -/+ 28), NADPH (87 +/- 2), and NADP+ (77 +/- 4) than smooth muscle (17 +/- 2, 96 +/- 14, 7 +/- 1, and 8 +/- 1, respectively). However, smooth muscle and endothelium do not differ from each other in the ratios of NADH/NAD+ or NADPH/NADP+. Cells cultured from smooth muscle and endothelium contained less ATP (93 +/- 2, 141 +/- 6) and had lower ratios of NADH/ NAD+ than the freshly isolated tissues but the NADPH/NADP+ ratios remained similar. We conclude that (a) freshly isolated smooth muscle and endothelium differ in their profiles of the energy metabolism nucleotides, and (b) culturing the cells alters the profile.
Collapse
Affiliation(s)
- Colin Halford
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | | | | |
Collapse
|
19
|
Grover AK, Samson SE, Robinson S, Kwan CY. Effects of peroxynitrite on sarcoplasmic reticulum Ca2+ pump in pig coronary artery smooth muscle. Am J Physiol Cell Physiol 2003; 284:C294-301. [PMID: 12529249 DOI: 10.1152/ajpcell.00297.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxynitrite generated in arteries from superoxide and NO may damage Ca(2+) pumps. Here, we report the effects of peroxynitrite on ATP-dependent azide-insensitive uptake of Ca(2+) into pig coronary artery vesicular membrane fractions F2 [enriched in plasma membrane (PM)] and F3 [enriched in sarcoplasmic reticulum (SR)]. Membranes were pretreated with peroxynitrite and then with DTT to quench this agent. This pretreatment inhibited Ca(2+) uptake in a peroxynitrite concentration-dependent manner, but the effect was more severe in F3 than in F2. The inhibition was thus not overcome by excess DTT used to quench peroxynitrite and was not affected if catalase, SOD, or mannitol was added along with peroxynitrite. Such damage to the pump protein would be difficult to repair if produced during ischemia-reperfusion. The acylphosphates formed with ATP in F3 corresponded mainly to the SR Ca(2+) pump (110 kDa), but in F2 both PM (140 kDa) and 110-kDa bands were observed. Peroxynitrite treatment of F2 inhibited only the 110-kDa band. Inhibition of Ca(2+) uptake and acylphosphate formation from ATP correlated well in peroxynitrite-treated F3 samples. However, inhibition of acylphosphates from orthophosphate (reverse reaction of the pump) was slightly poorer. Peroxynitrite treatment also covalently cross-linked the pump protein, yielding no dimers but only larger oligomers. In contrast, cross-linking of the SR Ca(2+) pump in skeletal and cardiac muscles gives dimers as the first oligomers. Therefore, we speculate that SERCA2 has a different quaternary structure in the coronary artery smooth muscle.
Collapse
Affiliation(s)
- Ashok K Grover
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada L8N 3Z5
| | | | | | | |
Collapse
|
20
|
Okon EB, Golbabaie A, van Breemen C. In the presence of L-NAME SERCA blockade induces endothelium-dependent contraction of mouse aorta through activation of smooth muscle prostaglandin H2/thromboxane A2 receptors. Br J Pharmacol 2002; 137:545-53. [PMID: 12359637 PMCID: PMC1573510 DOI: 10.1038/sj.bjp.0704884] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The mechanism of transient contractions induced by the sarcoplasmic-endoplasmic reticulum calcium ATPase (SERCA) blocker cyclopiazonic acid (CPA) in the presence of L-NAME was investigated in mouse aorta. 2. The contractions elicited by 10 micro M CPA required an intact endothelium, were dependent upon external Ca(2+) and were prevented by 10 micro M indomethacin, the inhibitor of prostaglandin synthesis, or 1 micro M SQ29548, the specific prostaglandin H2/thromboxane A2 (PGH2/TXA2) receptor blocker. 3. A blocker of receptor/store operated Ca(2+) channels and voltage gated calcium channels (VGCC), SK&F 96365 (10 micro M), completely abolished the contractions, while a specific blocker of VGCC nifedipine (1 micro M) inhibited them by one third. 4. Dichlorobenzamyl hydrochloride, a blocker of Na(+)/Ca(2+) exchange effectively prevented return of tension to baseline value. 5. At higher concentrations (30-100 micro M) CPA induced indomethacin-resistant tonic contractions of mouse aorta. The CPA dose response curve for tonic contractions is shifted to the right compared to the transient contractions suggesting that smooth muscle is less sensitive to CPA than endothelium. 6. PGH2/TXA2 receptors in mouse aorta are highly sensitive to the thromboxane analogue U46619 (EC(50) : 1.93 nM). This compound stimulates contractions even in the absence of external Ca(2+), which are abolished by the Rho-kinase inhibitor HA-1077. 7. The results suggest that 10 micro M CPA induced capacitive Ca(2+) entry in endothelial cells stimulating the release of PGH2/TXA2, which subsequently caused smooth muscle contraction dependent on Ca(2+) influx and myofilament sensitization by Rho-kinase. Higher concentrations of CPA (30-100 micro M) directly induced contraction of mouse aortic smooth muscle.
Collapse
MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Animals
- Aorta/drug effects
- Aorta/physiology
- Calcium Channel Blockers/pharmacology
- Calcium-Transporting ATPases/antagonists & inhibitors
- Calcium-Transporting ATPases/physiology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- In Vitro Techniques
- Male
- Mice
- Mice, Inbred C57BL
- Muscle, Smooth/drug effects
- Muscle, Smooth/physiology
- NG-Nitroarginine Methyl Ester/pharmacology
- Receptors, Prostaglandin/agonists
- Receptors, Prostaglandin/physiology
- Receptors, Thromboxane/agonists
- Receptors, Thromboxane/physiology
- Receptors, Thromboxane A2, Prostaglandin H2
- Sarcoplasmic Reticulum Calcium-Transporting ATPases
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
Collapse
Affiliation(s)
- Elena B Okon
- iCAPTUR E Center, University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.
| | | | | |
Collapse
|
21
|
Abstract
Papaverine is a vasodilator commonly used in the treatment of vasospasmic diseases such as cerebral spasm associated with subarachnoid hemorrhage, and in the prevention of spasm of coronary artery bypass graft by intraluminal and/or extraluminal administration. In this study, we examined whether papaverine in the range of concentrations used clinically causes apoptosis of vascular endothelial and smooth muscle cells. Apoptotic cells were identified by morphological changes and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. In porcine coronary endothelial cells (EC) and rat aortic smooth muscle cells (SMC), papaverine at the concentration of 10(-3) M induced membrane blebbing within 1 hour of incubation. Nuclear condensation and fragmentation were found after 24 hours of treatment. The number of apoptotic cells stained with the TUNEL method was significantly higher in the EC and the SMC after 24 hours of incubation with papaverine at the concentrations of 10(-4) and 10(-3) M than their respective controls. Acidified saline solution (pH 4.8, as control for 10(-3) M papaverine hydrochloride) did not cause apoptosis in these cells. These results showed that papaverine could damage endothelial and smooth muscle cells by inducing changes which are associated with events leading to apoptosis. Since integrity of endothelial cells is critical for normal vascular function, vascular administration of papaverine for clinical use, especially at high concentrations (> or = 10(-4) M), should be re-considered.
Collapse
Affiliation(s)
- Y J Gao
- Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
| | | | | |
Collapse
|
22
|
Abstract
The control and maintenance of vascular tone is due to a balance between vasoconstrictor and vasodilator pathways. Vasomotor responses to neural, metabolic and physical factors vary between vessels in different vascular beds, as well as along the same bed, particularly as vessels become smaller. These differences result from variation in the composition of neurotransmitters released by perivascular nerves, variation in the array and activation of receptor subtypes expressed in different vascular beds and variation in the signal transduction pathways activated in either the vascular smooth muscle or endothelial cells. As the study of vasomotor responses often requires pre-existing tone, some of the reported heterogeneity in the relative contributions of different vasodilator mechanisms may be compounded by different experimental conditions. Biochemical variations, such as the expression of ion channels, connexin subtypes and other important components of second messenger cascades, have been documented in the smooth muscle and endothelial cells in different parts of the body. Anatomical variations, in the presence and prevalence of gap junctions between smooth muscle cells, between endothelial cells and at myoendothelial gap junctions, between the two cell layers, have also been described. These factors will contribute further to the heterogeneity in local and conducted responses.
Collapse
Affiliation(s)
- C E Hill
- Autonomic Synapse Group, Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra 0200 ACT, Australia.
| | | | | |
Collapse
|