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Li K, Li Y, Chen Y, Chen T, Yang Y, Li P. Ion Channels Remodeling in the Regulation of Vascular Hyporesponsiveness During Shock. Microcirculation 2024; 31:e12874. [PMID: 39011763 DOI: 10.1111/micc.12874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 04/07/2024] [Accepted: 06/16/2024] [Indexed: 07/17/2024]
Abstract
Shock is characterized with vascular hyporesponsiveness to vasoconstrictors, thereby to cause refractory hypotension, insufficient tissue perfusion, and multiple organ dysfunction. The vascular hyporeactivity persisted even though norepinephrine and fluid resuscitation were administrated, it is of critical importance to find new potential target. Ion channels are crucial in the regulation of cell membrane potential and affect vasoconstriction and vasodilation. It has been demonstrated that many types of ion channels including K+ channels, Ca2+ permeable channels, and Na+ channels exist in vascular smooth muscle cells and endothelial cells, contributing to the regulation of vascular homeostasis and vasomotor function. An increasing number of studies suggested that the structural and functional alterations of ion channels located in arteries contribute to vascular hyporesponsiveness during shock, but the underlying mechanisms remained to be fully clarified. Therefore, the expression and functional changes in ion channels in arteries associated with shock are reviewed, to pave the way for further exploring the potential of ion channel-targeted compounds in treating refractory hypotension in shock.
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Affiliation(s)
- Keqing Li
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yuan Li
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yinghong Chen
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Tangting Chen
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yan Yang
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Pengyun Li
- The Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
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Liu J, Tan J, Tang B, Guo J. Unveiling the role of iPLA 2β in neurodegeneration: From molecular mechanisms to advanced therapies. Pharmacol Res 2024; 202:107114. [PMID: 38395207 DOI: 10.1016/j.phrs.2024.107114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/08/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Calcium-independent phospholipase A2β (iPLA2β), a member of the phospholipase A2 (PLA2s) superfamily, is encoded by the PLA2G6 gene. Mutations in the PLA2G6 gene have been identified as the primary cause of infantile neuroaxonal dystrophy (INAD) and, less commonly, as a contributor to Parkinson's disease (PD). Recent studies have revealed that iPLA2β deficiency leads to neuroinflammation, iron accumulation, mitochondrial dysfunction, lipid dysregulation, and other pathological changes, forming a complex pathogenic network. These discoveries shed light on potential mechanisms underlying PLA2G6-associated neurodegeneration (PLAN) and offer valuable insights for therapeutic development. This review provides a comprehensive analysis of the fundamental characteristics of iPLA2β, its association with neurodegeneration, the pathogenic mechanisms involved in PLAN, and potential targets for therapeutic intervention. It offers an overview of the latest advancements in this field, aiming to contribute to ongoing research endeavors and facilitate the development of effective therapies for PLAN.
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Affiliation(s)
- Jiabin Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jieqiong Tan
- Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China; Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China.
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Garcia SM, Herbert LM, Walker BR, Resta TC, Jernigan NL. Coupling of store-operated calcium entry to vasoconstriction is acid-sensing ion channel 1a dependent in pulmonary but not mesenteric arteries. PLoS One 2020; 15:e0236288. [PMID: 32702049 PMCID: PMC7377459 DOI: 10.1371/journal.pone.0236288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/01/2020] [Indexed: 12/31/2022] Open
Abstract
Although voltage-gated Ca2+ channels (VGCC) are a major Ca2+ entry pathway in vascular smooth muscle cells (VSMCs), several other Ca2+-influx mechanisms exist and play important roles in vasoreactivity. One of these is store-operated Ca2+ entry (SOCE), mediated by an interaction between STIM1 and Orai1. Although SOCE is an important mechanism of Ca2+ influx in non-excitable cells (cells that lack VGCC); there is debate regarding the contribution of SOCE to regulate VSMC contractility and the molecular components involved. Our previous data suggest acid-sensing ion channel 1a (ASIC1a) is a necessary component of SOCE and vasoconstriction in small pulmonary arteries. However, it is unclear if ASIC1a similarly contributes to SOCE and vascular reactivity in systemic arteries. Considering the established role of Orai1 in mediating SOCE in the systemic circulation, we hypothesize the involvement of ASIC1a in SOCE and resultant vasoconstriction is unique to the pulmonary circulation. To test this hypothesis, we examined the roles of Orai1 and ASIC1a in SOCE- and endothelin-1 (ET-1)-induced vasoconstriction in small pulmonary and mesenteric arteries. We found SOCE is coupled to vasoconstriction in pulmonary arteries but not mesenteric arteries. In pulmonary arteries, inhibition of ASIC1a but not Orai1 attenuated SOCE- and ET-1-induced vasoconstriction. However, neither inhibition of ASIC1a nor Orai1 altered ET-1-induced vasoconstriction in mesenteric arteries. We conclude that SOCE plays an important role in pulmonary, but not mesenteric, vascular reactivity. Furthermore, in contrast to the established role of Orai1 in SOCE in non-excitable cells, the SOCE response in pulmonary VSMCs is largely mediated by ASIC1a.
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Affiliation(s)
- Selina M. Garcia
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Lindsay M. Herbert
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Benjimen R. Walker
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Thomas C. Resta
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Nikki L. Jernigan
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
- * E-mail:
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Schach C, Wester M, Leibl F, Redel A, Gruber M, Maier LS, Endemann D, Wagner S. Reduced store-operated Ca 2+ entry impairs mesenteric artery function in response to high external glucose in type 2 diabetic ZDF rats. Clin Exp Pharmacol Physiol 2020; 47:1145-1157. [PMID: 32147830 DOI: 10.1111/1440-1681.13300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 02/15/2020] [Accepted: 03/05/2020] [Indexed: 11/28/2022]
Abstract
Diabetes is a major risk factor for cardiovascular disease, affecting both endothelial and smooth muscle cells. Store-operated Ca2+ channels (SOCCs) have been implicated in many diabetic complications. Vascular dysfunction is common in patients with diabetes, but the role of SOCCs in diabetic vasculopathy is still unclear. Our research aimed to investigate the effects of high glucose (HG) on store-operated Ca2+ entry (SOCE) in small arteries. Small mesenteric arteries from type 2 diabetic Zucker fatty rats (ZDF) versus their non-diabetic controls (Zucker lean, ZL) were examined in a pressurized myograph. Vascular smooth muscle cells (VSMC) were isolated and intracellular Ca2+ was measured (Fura 2-AM). A specific protocol to deplete intracellular Ca2+ stores and thereby open SOCCs, as well as pharmacological SOCE inhibitors (SKF-96365, BTP-2), were used to artificially activate and inhibit SOCE, respectively. High glucose (40 mmol/L) relaxed arteries in a SKF-sensitive manner. Diabetic arteries exhibited reduced HG-induced relaxation, as well as reduced contraction after Ca2+ replenishment. Further, the rise in intracellular Ca2+ on account of SOCE is diminished in diabetic versus non-diabetic VSMCs and was insensitive to HG in diabetic VSMCs. The expression of SOCC proteins was measured, detecting a downregulation of Orai1 in diabetes. In conclusion, diabetes leads to a reduction of SOCE and SOCE-induced contraction, which is unresponsive to HG-mediated inhibition. The reduced expression of Orai1 in diabetic arteries could account for the observed reduction in SOCE.
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Affiliation(s)
- Christian Schach
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Michael Wester
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Florian Leibl
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Andreas Redel
- Klinik für Anästhesiologie, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Michael Gruber
- Klinik für Anästhesiologie, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Lars S Maier
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Dierk Endemann
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Stefan Wagner
- Abteilung für Kardiologie, Klinik und Poliklinik für Innere Medizin II, Universitäres Herzzentrum Regensburg, Universitätsklinikum Regensburg, Regensburg, Germany
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Manoury B, Idres S, Leblais V, Fischmeister R. Ion channels as effectors of cyclic nucleotide pathways: Functional relevance for arterial tone regulation. Pharmacol Ther 2020; 209:107499. [PMID: 32068004 DOI: 10.1016/j.pharmthera.2020.107499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Numerous mediators and drugs regulate blood flow or arterial pressure by acting on vascular tone, involving cyclic nucleotide intracellular pathways. These signals lead to regulation of several cellular effectors, including ion channels that tune cell membrane potential, Ca2+ influx and vascular tone. The characterization of these vasocontrictive or vasodilating mechanisms has grown in complexity due to i) the variety of ion channels that are expressed in both vascular endothelial and smooth muscle cells, ii) the heterogeneity of responses among the various vascular beds, and iii) the number of molecular mechanisms involved in cyclic nucleotide signalling in health and disease. This review synthesizes key data from literature that highlight ion channels as physiologically relevant effectors of cyclic nucleotide pathways in the vasculature, including the characterization of the molecular mechanisms involved. In smooth muscle cells, cation influx or chloride efflux through ion channels are associated with vasoconstriction, whereas K+ efflux repolarizes the cell membrane potential and mediates vasodilatation. Both categories of ion currents are under the influence of cAMP and cGMP pathways. Evidence that some ion channels are influenced by CN signalling in endothelial cells will also be presented. Emphasis will also be put on recent data touching a variety of determinants such as phosphodiesterases, EPAC and kinase anchoring, that complicate or even challenge former paradigms.
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Affiliation(s)
- Boris Manoury
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France.
| | - Sarah Idres
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Véronique Leblais
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
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Amplification of the COX/TXS/TP receptor pathway enhances uridine diphosphate-induced contraction by advanced glycation end products in rat carotid arteries. Pflugers Arch 2019; 471:1505-1517. [PMID: 31736003 DOI: 10.1007/s00424-019-02330-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 12/18/2022]
Abstract
Advanced glycation end products (AGEs) play a pivotal role in vascular functions under various pathophysiological conditions. Although uridine diphosphate (UDP) is an important extracellular nucleotide, the relationship between AGEs and UDP regarding their effect on vascular functions remains unclear. Therefore, we investigated the effects of AGE-bovine serum albumin (AGE-BSA) on UDP-mediated responses in rat thoracic aorta and carotid arteries. In rat thoracic aorta, UDP-induced relaxation was observed and this relaxation was similar between control (1.0 v/v% PBS) and AGE-BSA-treated (0.1 mg/mL for 60 min) groups. In contrast, contraction but not relaxation was obtained following UDP application to carotid arteries with and without endothelia; contraction was greater in the AGE-BSA-treated group than in the control group. The difference in UDP-induced contraction between the two groups was not abolished by the use of a nitric oxide synthase (NOS) inhibitor, whereas it was abolished by the use of cyclooxygenase (COX), thromboxane synthase (TXS), and thromboxane-prostanoid (TP) receptor antagonist. Further, the difference in UDP-induced contraction was not abolished by the use of a cPLA2 inhibitor, whereas it was abolished by the use of an iPLA2 inhibitor. UDP increased TXA2 release in both groups, and its level was similar in both groups. Moreover, the release of PGE2, PGF2α, and PGI2 was similar among the groups. Under NOS inhibition, TP receptor agonist-induced contraction increased in the AGE-BSA-treated group (vs. control group). In conclusion, the increase in UDP-induced carotid arterial contraction by AGE-BSA can be attributed to an increase in the COX/TXS/TP receptor pathway, particularly, TP receptor signaling.
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7
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Avila-Medina J, Mayoral-Gonzalez I, Dominguez-Rodriguez A, Gallardo-Castillo I, Ribas J, Ordoñez A, Rosado JA, Smani T. The Complex Role of Store Operated Calcium Entry Pathways and Related Proteins in the Function of Cardiac, Skeletal and Vascular Smooth Muscle Cells. Front Physiol 2018; 9:257. [PMID: 29618985 PMCID: PMC5872157 DOI: 10.3389/fphys.2018.00257] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/06/2018] [Indexed: 12/11/2022] Open
Abstract
Cardiac, skeletal, and smooth muscle cells shared the common feature of contraction in response to different stimuli. Agonist-induced muscle's contraction is triggered by a cytosolic free Ca2+ concentration increase due to a rapid Ca2+ release from intracellular stores and a transmembrane Ca2+ influx, mainly through L-type Ca2+ channels. Compelling evidences have demonstrated that Ca2+ might also enter through other cationic channels such as Store-Operated Ca2+ Channels (SOCCs), involved in several physiological functions and pathological conditions. The opening of SOCCs is regulated by the filling state of the intracellular Ca2+ store, the sarcoplasmic reticulum, which communicates to the plasma membrane channels through the Stromal Interaction Molecule 1/2 (STIM1/2) protein. In muscle cells, SOCCs can be mainly non-selective cation channels formed by Orai1 and other members of the Transient Receptor Potential-Canonical (TRPC) channels family, as well as highly selective Ca2+ Release-Activated Ca2+ (CRAC) channels, formed exclusively by subunits of Orai proteins likely organized in macromolecular complexes. This review summarizes the current knowledge of the complex role of Store Operated Calcium Entry (SOCE) pathways and related proteins in the function of cardiac, skeletal, and vascular smooth muscle cells.
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Affiliation(s)
- Javier Avila-Medina
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain.,Institute of Biomedicine of Seville, University Hospital of Virgen del Rocío, CSIC, University of Seville, Sevilla, Spain.,CIBERCV, Madrid, Spain
| | | | - Alejandro Dominguez-Rodriguez
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain.,Institute of Biomedicine of Seville, University Hospital of Virgen del Rocío, CSIC, University of Seville, Sevilla, Spain.,CIBERCV, Madrid, Spain
| | | | - Juan Ribas
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain
| | - Antonio Ordoñez
- CIBERCV, Madrid, Spain.,Department of Surgery, University of Seville, Sevilla, Spain
| | - Juan A Rosado
- Cell Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain.,Institute of Biomedicine of Seville, University Hospital of Virgen del Rocío, CSIC, University of Seville, Sevilla, Spain.,CIBERCV, Madrid, Spain
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8
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Zhu M, Ren Z, Possomato-Vieira JS, Khalil RA. Restoring placental growth factor-soluble fms-like tyrosine kinase-1 balance reverses vascular hyper-reactivity and hypertension in pregnancy. Am J Physiol Regul Integr Comp Physiol 2016; 311:R505-21. [PMID: 27280428 PMCID: PMC5142222 DOI: 10.1152/ajpregu.00137.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/03/2016] [Indexed: 11/22/2022]
Abstract
Preeclampsia (PE) is a pregnancy-related hypertensive disorder (HTN-Preg) with unclear mechanism. An imbalance between antiangiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) and angiogenic placental growth factor (PlGF) has been observed in PE, but the vascular targets and signaling pathways involved are unclear. We assessed the extent of sFlt-1/PlGF imbalance and vascular dysfunction in a rat model of HTN-Preg produced by reduction of uteroplacental perfusion pressure (RUPP), and tested whether inducing a comparable sFlt-1/PlGF imbalance by infusing sFlt-1 (10 μg·kg(-1)·day(-1)) in day 14 pregnant (Preg) rats cause similar increases in blood pressure (BP) and vascular reactivity. Using these guiding measurements, we then tested whether restoring sFlt-1/PlGF balance by infusing PIGF (20 μg·kg(-1)·day(-1)) in RUPP rats would improve BP and vascular function. On gestational day 19, BP was in Preg+sFlt-1 and RUPP > Preg, and in RUPP+PlGF < RUPP rats. Plasma sFlt-1/PlGF ratio was increased in Preg+sFlt-1, and RUPP and was reduced in RUPP+PlGF rats. In isolated endothelium-intact aorta, carotid, mesenteric, and renal artery, phenylephrine (Phe)- and high KCl-induced contraction was in Preg+sFlt-1 and RUPP > Preg, and in RUPP+PlGF < RUPP. The differences in vascular reactivity to Phe and KCl between groups were less apparent in vessels treated with the nitric oxide synthase (NOS) inhibitor l-NAME or guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) or endothelium-denuded, suggesting changes in endothelial NO-cGMP pathway. In Phe precontracted vessels, ACh-induced relaxation was in Preg+sFlt-1 and RUPP < Preg, and in RUPP+PlGF > RUPP, and was blocked by N(ω)-nitro-l-arginine methyl ester (l-NAME) or ODQ treatment or endothelium removal. Western blots revealed that aortic total endothelial NOS (eNOS) and activated phosphorylated-eNOS were in Preg+sFlt-1 and RUPP < Preg and in RUPP+PlGF > RUPP. ACh-induced vascular nitrate/nitrite production was in Preg+sFlt-1 and RUPP < Preg, and in RUPP+PlGF > RUPP. Vascular relaxation to the exogenous NO donor sodium nitroprusside was not different among groups. Thus, a tilt in the angiogenic balance toward anti-angiogenic sFlt-1 is associated with decreased vascular relaxation and increased vasoconstriction and BP. Restoring the angiogenic/antiangiogenic balance using PlGF enhances endothelial NO-cGMP vascular relaxation and decreases vasoconstriction and BP in HTN-Preg rats and could offer a new approach in the management of PE.
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Affiliation(s)
- Minglin Zhu
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Zongli Ren
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - José S Possomato-Vieira
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Raouf A Khalil
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
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Ávila-Medina J, Calderón-Sánchez E, González-Rodríguez P, Monje-Quiroga F, Rosado JA, Castellano A, Ordóñez A, Smani T. Orai1 and TRPC1 Proteins Co-localize with CaV1.2 Channels to Form a Signal Complex in Vascular Smooth Muscle Cells. J Biol Chem 2016; 291:21148-21159. [PMID: 27535226 DOI: 10.1074/jbc.m116.742171] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Indexed: 11/06/2022] Open
Abstract
Voltage-dependent CaV1.2 L-type Ca2+ channels (LTCC) are the main route for calcium entry in vascular smooth muscle cells (VSMC). Several studies have also determined the relevant role of store-operated Ca2+ channels (SOCC) in vascular tone regulation. Nevertheless, the role of Orai1- and TRPC1-dependent SOCC in vascular tone regulation and their possible interaction with CaV1.2 are still unknown. The current study sought to characterize the co-activation of SOCC and LTCC upon stimulation by agonists, and to determine the possible crosstalk between Orai1, TRPC1, and CaV1.2. Aorta rings and isolated VSMC obtained from wild type or smooth muscle-selective conditional CaV1.2 knock-out (CaV1.2KO) mice were used to study vascular contractility, intracellular Ca2+ mobilization, and distribution of ion channels. We found that serotonin (5-HT) or store depletion with thapsigargin (TG) enhanced intracellular free Ca2+ concentration ([Ca2+]i) and stimulated aorta contraction. These responses were sensitive to LTCC and SOCC inhibitors. Also, 5-HT- and TG-induced responses were significantly attenuated in CaV1.2KO mice. Furthermore, hyperpolarization induced with cromakalim or valinomycin significantly reduced both 5-HT and TG responses, whereas these responses were enhanced with LTCC agonist Bay-K-8644. Interestingly, in situ proximity ligation assay revealed that CaV1.2 interacts with Orai1 and TRPC1 in untreated VSMC. These interactions enhanced significantly after stimulation of cells with 5-HT and TG. Therefore, these data indicate for the first time a functional interaction between Orai1, TRPC1, and CaV1.2 channels in VSMC, confirming that upon agonist stimulation, vessel contraction involves Ca2+ entry due to co-activation of Orai1- and TRPC1-dependent SOCC and LTCC.
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Affiliation(s)
- Javier Ávila-Medina
- From the Departamento de Fisiología Médica y Biofísica and Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Eva Calderón-Sánchez
- Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | | | - Francisco Monje-Quiroga
- the Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Wien, Austria, and
| | - Juan Antonio Rosado
- the Departamento de Fisiología, Universidad de Extremadura, 10071 Cáceres, Spain
| | | | - Antonio Ordóñez
- Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Tarik Smani
- From the Departamento de Fisiología Médica y Biofísica and Groupo de Fisiopatología Cardiovascular, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain,
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10
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Contrasting Patterns of Agonist-induced Store-operated Ca2+ Entry and Vasoconstriction in Mesenteric Arteries and Aorta With Aging. J Cardiovasc Pharmacol 2016; 65:571-8. [PMID: 25636074 PMCID: PMC4461395 DOI: 10.1097/fjc.0000000000000225] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Ca is a crucial factor in the regulation of smooth muscle contraction. Store-operated Ca entry (SOCE) is one pathway that mediates Ca influx and smooth muscle contraction. Vessel contraction function usually alters with aging to cause severe vascular-related diseases. However, the underlying mechanism is still not fully understood. Here, we assessed intracellular Ca and vessel tension and found that SOCE and SOCE-mediated contraction of vascular smooth muscle cells (VSMCs) was reduced in aorta but increased in mesenteric arteries from aged rats. The results of Western blot and immunofluorescence staining show that the expression levels of Orai1, a store-operated Ca channel, were increased in VSMCs of mesenteric arteries but were reduced in VSMCs of aorta with aging. In conclusion, we demonstrated that the changing pattern of SOCE and SOCE-mediated contraction of VSMCs is completely reversed in mesenteric arteries and aorta with aging, providing a potential therapeutic target for clinical treatment in age-related vascular diseases.
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11
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Smani T, Domínguez-Rodriguez A, Callejo-García P, Rosado JA, Avila-Medina J. Phospholipase A2 as a Molecular Determinant of Store-Operated Calcium Entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:111-31. [PMID: 27161227 DOI: 10.1007/978-3-319-26974-0_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Activation of phospholipases A2 (PLA2) leads to the generation of biologically active lipid products that can affect numerous cellular events. Ca(2+)-independent PLA2 (iPLA2), also called group VI phospholipase A2, is one of the main types forming the superfamily of PLA2. Beside of its role in phospholipid remodeling, iPLA2 has been involved in intracellular Ca(2+) homeostasis regulation. Several studies proposed iPLA2 as an essential molecular player of store operated Ca(2+) entry (SOCE) in a large number of excitable and non-excitable cells. iPLA2 activation releases lysophosphatidyl products, which were suggested as agonists of store operated calcium channels (SOCC) and other TRP channels. Herein, we will review the important role of iPLA2 on the intracellular Ca(2+) handling focusing on its role in SOCE regulation and its implication in physiological and/or pathological processes.
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Affiliation(s)
- Tarik Smani
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain.
| | - Alejandro Domínguez-Rodriguez
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain
| | - Paula Callejo-García
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain
| | - Juan A Rosado
- Departamento de Fisiología, University of Extremadura, Cáceres, Spain
| | - Javier Avila-Medina
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain
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Garza AE, Pojoga LH, Moize B, Hafiz WM, Opsasnick LA, Siddiqui WT, Horenstein M, Adler GK, Williams GH, Khalil RA. Critical Role of Striatin in Blood Pressure and Vascular Responses to Dietary Sodium Intake. Hypertension 2015; 66:674-80. [PMID: 26169051 DOI: 10.1161/hypertensionaha.115.05600] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/17/2015] [Indexed: 12/12/2022]
Abstract
Striatin is a protein regulator of vesicular trafficking in neurons that also binds caveolin-1 and Ca(2+)-calmodulin and could activate endothelial nitric oxide synthase. We have shown that striatin colocalizes with the mineralocorticoid receptor and that mineralocorticoid receptor activation increases striatin levels in vascular cells. To test whether striatin is a regulator of vascular function, wild-type and heterozygous striatin-deficient mice (Strn(+/-)) were randomized in crossover intervention to restricted (0.03%) and liberal sodium (1.6%) diets for 7 days on each diet, and blood pressure and aortic vascular function were measured. Compared with wild-type, sodium restriction significantly reduced blood pressure in Strn(+/-). On liberal salt intake, phenylephrine and high KCl caused a greater vascular contraction in Strn(+/-) than wild-type, and endothelium removal, nitric oxide synthase inhibitor L-NAME, and guanylate cyclase inhibitor ODQ enhanced phenylephrine contraction to a smaller extent in Strn(+/-) than wild-type. On liberal salt, acetylcholine relaxation was less in Strn(+/-) than in wild-type, and endothelium removal, L-NAME, and ODQ blocked acetylcholine relaxation, suggesting changes in endothelial NO-cGMP. On liberal salt, endothelial nitric oxide synthase mRNA expression and the ratio of endothelial nitric oxide synthase activator pAkt/total Akt were decreased in Strn(+/-) versus wild-type. Vascular relaxation to NO donor sodium nitroprusside was not different among groups. Thus, striatin deficiency is associated with salt sensitivity of blood pressure, enhanced vasoconstriction, and decreased vascular relaxation, suggesting a critical role for striatin, through modulation of endothelial NO-cGMP, in regulation of vascular function and BP during changes in sodium intake.
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Affiliation(s)
- Amanda E Garza
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Luminita H Pojoga
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Burhanuddin Moize
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Wan M Hafiz
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Lauren A Opsasnick
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Waleed T Siddiqui
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Michael Horenstein
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Gail K Adler
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Gordon H Williams
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Raouf A Khalil
- From the Cardiovascular Endocrine Section, Division of Endocrinology, Diabetes and Hypertension (A.E.G., L.H.P., B.M., W.M.H., G.K.A., G.H.W.), and Division of Vascular Surgery (L.A.O., W.T.S., M.H., R.A.K.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
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Goulopoulou S, Webb RC. Symphony of vascular contraction: how smooth muscle cells lose harmony to signal increased vascular resistance in hypertension. Hypertension 2014; 63:e33-9. [PMID: 24470463 DOI: 10.1161/hypertensionaha.113.02444] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Styliani Goulopoulou
- Department of Physiology, Georgia Regents University, 1120 Fifteenth St, Augusta, GA 30912.
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Pojoga LH, Yao TM, Opsasnick LA, Garza AE, Reslan OM, Adler GK, Williams GH, Khalil RA. Dissociation of hyperglycemia from altered vascular contraction and relaxation mechanisms in caveolin-1 null mice. J Pharmacol Exp Ther 2013; 348:260-70. [PMID: 24281385 DOI: 10.1124/jpet.113.209189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hyperglycemia and endothelial dysfunction are associated with hypertension, but the specific causality and genetic underpinning are unclear. Caveolin-1 (cav-1) is a plasmalemmal anchoring protein and modulator of vascular function and glucose homeostasis. Cav-1 gene variants are associated with reduced insulin sensitivity in hypertensive individuals, and cav-1(-/-) mice show endothelial dysfunction, hyperglycemia, and increased blood pressure (BP). On the other hand, insulin-sensitizing therapy with metformin may inadequately control hyperglycemia while affecting the vascular outcome in certain patients with diabetes. To test whether the pressor and vascular changes in cav-1 deficiency states are related to hyperglycemia and to assess the vascular mechanisms of metformin under these conditions, wild-type (WT) and cav-1(-/-) mice were treated with either placebo or metformin (400 mg/kg daily for 21 days). BP and fasting blood glucose were in cav-1(-/-) > WT and did not change with metformin. Phenylephrine (Phe)- and KCl-induced aortic contraction was in cav-1(-/-) < WT; endothelium removal, the nitric-oxide synthase (NOS) blocker L-NAME (N(ω)-nitro-L-arginine methyl ester), or soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) enhanced Phe contraction, and metformin blunted this effect. Acetylcholine-induced relaxation was in cav-1(-/-) > WT, abolished by endothelium removal, L-NAME or ODQ, and reduced with metformin. Nitric oxide donor sodium nitroprusside was more potent in inducing relaxation in cav-1(-/-) than in WT, and metformin reversed this effect. Aortic eNOS, AMPK, and sGC were in cav-1(-/-) > WT, and metformin decreased total and phosphorylated eNOS and AMPK in cav-1(-/-). Thus, metformin inhibits both vascular contraction and NO-cGMP-dependent relaxation but does not affect BP or blood glucose in cav-1(-/-) mice, suggesting dissociation of hyperglycemia from altered vascular function in cav-1-deficiency states.
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Affiliation(s)
- Luminita H Pojoga
- Cardiovascular Endocrine Section, Endocrinology, Diabetes and Hypertension Division (L.H.P., T.M.Y., A.E.G., G.K.A., G.H.W.), and Division of Vascular and Endovascular Surgery (L.A.O., O.M.R., R.A.K.), Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts
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Li G, Zhang Z, Wang R, Ma W, Yang Y, Wei J, Wei Y. Suppression of STIM1 inhibits human glioblastoma cell proliferation and induces G0/G1 phase arrest. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2013; 32:20. [PMID: 23578185 PMCID: PMC3639102 DOI: 10.1186/1756-9966-32-20] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/02/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND Depletion of calcium (Ca2+) from the endoplasmic reticulum (ER) activates the ubiquitous store-operated Ca2+ entry (SOCE) pathway which sustains long-term Ca2+ signals and is critical for cellular functions. Stromal interacting molecule 1 (STIM1) serves a dual role as an ER Ca2+ sensor and activator of SOCE. Aberrant expression of STIM1 could be observed in several human cancer cells. However, the role of STIM1 in regulating tumorigenesis of human glioblastoma still remains unclear. METHODS Expression of STIM1 protein in a panel of human glioblastoma cell lines (U251, U87 and U373) in different transformation level were evaluated by Western blot method. STIM1 loss of function was performed on U251 cells, derived from grade IV astrocytomas-glioblastoma multiforme with a lentvirus-mediated short harpin RNA (shRNA) method. The biological impacts after knock down of STIM1 on glioblastoma cells were investigated in vitro and in vivo. RESULTS We discovered that STIM1 protein was expressed in U251, U87 and U373 cells, and especially higher in U251 cells. RNA interference efficiently downregulated the expression of STIM1 in U251 cells at both mRNA and protein levels. Specific downregulation of STIM1 inhibited U251 cell proliferation by inducing cell cycle arrest in G0/G1 phase through regulation of cell cycle-related genes, such as p21Waf1/Cip1, cyclin D1 and cyclin-dependent kinase 4 (CDK4), and the antiproliferative effect of STIM1 silencing was also observed in U251 glioma xenograft tumor model. CONCLUSION Our findings confirm STIM1 as a rational therapeutic target in human glioblastoma, and also indicate that lentivirus-mediated STIM1 silencing is a promising therapeutic strategy for human glioblastoma.
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Affiliation(s)
- Guilin Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No.1 Shuaifuyuan, Wangfujing, Dongcheng District, Beijing 100730, PR China
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16
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Saab-Aoudé S, Bron AM, Creuzot-Garcher CP, Bretillon L, Acar N. A mouse model of in vivo chemical inhibition of retinal calcium-independent phospholipase A2 (iPLA2). Biochimie 2013; 95:903-11. [DOI: 10.1016/j.biochi.2012.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/11/2012] [Indexed: 10/27/2022]
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18
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Calderon LE, Liu S, Su W, Xie Z, Guo Z, Eberhard W, Gong MC. iPLA2β overexpression in smooth muscle exacerbates angiotensin II-induced hypertension and vascular remodeling. PLoS One 2012; 7:e31850. [PMID: 22363752 PMCID: PMC3282780 DOI: 10.1371/journal.pone.0031850] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/13/2012] [Indexed: 12/12/2022] Open
Abstract
Objectives Calcium independent group VIA phospholipase A2 (iPLA2β) is up-regulated in vascular smooth muscle cells in some diseases, but whether the up-regulated iPLA2β affects vascular morphology and blood pressure is unknown. The current study addresses this question by evaluating the basal- and angiotensin II infusion-induced vascular remodeling and hypertension in smooth muscle specific iPLA2β transgenic (iPLA2β -Tg) mice. Method and Results Blood pressure was monitored by radiotelemetry and vascular remodeling was assessed by morphologic analysis. We found that the angiotensin II-induced increase in diastolic pressure was significantly higher in iPLA2β-Tg than iPLA2β-Wt mice, whereas, the basal blood pressure was not significantly different. The media thickness and media∶lumen ratio of the mesenteric arteries were significantly increased in angiotensin II-infused iPLA2β-Tg mice. Analysis revealed no difference in vascular smooth muscle cell proliferation. In contrast, adenovirus-mediated iPLA2β overexpression in cultured vascular smooth muscle cells promoted angiotensin II-induced [3H]-leucine incorporation, indicating enhanced hypertrophy. Moreover, angiotensin II infusion-induced c-Jun phosphorylation in vascular smooth muscle cells overexpressing iPLA2β to higher levels, which was abolished by inhibition of 12/15 lipoxygenase. In addition, we found that angiotensin II up-regulated the endogenous iPLA2β protein in-vitro and in-vivo. Conclusion The present study reports that iPLA2β up-regulation exacerbates angiotensin II-induced vascular smooth muscle cell hypertrophy, vascular remodeling and hypertension via the 12/15 lipoxygenase and c-Jun pathways.
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MESH Headings
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiopathology
- Arachidonate 15-Lipoxygenase
- Arachidonic Acid/metabolism
- Blood Pressure/drug effects
- Cell Proliferation/drug effects
- Diastole/drug effects
- Group VI Phospholipases A2/metabolism
- Hypertension/enzymology
- Hypertension/pathology
- Hypertension/physiopathology
- Hypertrophy
- Leucine/metabolism
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/pathology
- Organ Specificity/drug effects
- Proto-Oncogene Proteins c-jun/metabolism
- Rats
- Signal Transduction/drug effects
- p38 Mitogen-Activated Protein Kinases/metabolism
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Affiliation(s)
- Lindsay E. Calderon
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Shu Liu
- Department of Internal Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wen Su
- Department of Internal Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Zhongwen Xie
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Zhenheng Guo
- Department of Internal Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wanda Eberhard
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Ming C. Gong
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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Domínguez-Rodríguez A, Díaz I, Rodríguez-Moyano M, Calderón-Sánchez E, Rosado JA, Ordóñez A, Smani T. Urotensin-II signaling mechanism in rat coronary artery: role of STIM1 and Orai1-dependent store operated calcium influx in vasoconstriction. Arterioscler Thromb Vasc Biol 2012; 32:1325-32. [PMID: 22223729 DOI: 10.1161/atvbaha.111.243014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Human urotensin-II (UII) is considered the most potentendogenous vasoconstrictor discovered to date, although the precise mechanism activated downstream of its receptor UTS2R in blood vessels remains elusive. The aim of this study was to determine the role of the store operated Ca(2+) entry (SOCE) signaling pathway in UII-induced coronary artery vasoconstriction. METHODS AND RESULTS We used a combination of isometric tension measurement, Ca(2+) imaging, pharmacology, and molecular approaches to study UII-mediated rat coronary artery vasoconstriction and intracellular Ca(2+) mobilization in coronary smooth muscle cells. We found that UII promoted dose-dependent vasoconstriction and elicited Ca(2+) and Mn(2+) influx, which were sensitive to classical SOCE inhibitors. In addition, knockdown of either STIM1 or Orai1 essentially inhibited UII-mediated SOCE and prevented UII but not high-KCL evoked contraction in transfected coronary artery. Moreover, we found that Ca(2+)-independent phospholipase A(2)β was involved in UII effects and that is colocalized with STIM1 in different submembrane compartments. Importantly, STIM1 but not Orai1 downregulation inhibits significantly independent phospholipase A(2) activation. Furthermore, lysophosphatidylcholine, an independent phospholipase A(2) product, activated Orai1 but not STIM1-dependent contraction and SOCE. CONCLUSIONS Here, we demonstrated that different critical players of SOCE signaling pathway are required for UII-induced vasoconstriction of rat coronary artery.
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Suzuki K, Saito SY, Ishikawa T. Involvement of phosphatidylcholine-specific phospholipase C in thromboxane A₂ receptor-mediated extracellular Ca²⁺ influx in rat aorta. Eur J Pharmacol 2011; 677:123-30. [PMID: 22200631 DOI: 10.1016/j.ejphar.2011.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 11/29/2011] [Accepted: 12/07/2011] [Indexed: 11/26/2022]
Abstract
An involvement of signal transduction other than phosphatidylinositol turnover in thromboxane A(2) receptor (TP receptor)-mediated vascular contraction was investigated in rat aorta. The contraction induced by U46619, a TP receptor agonist, at low concentrations (≤ 30 nM) was partially inhibited by verapamil, an inhibitor of voltage-dependent Ca(2+) channels (VDCC), and was further diminished in Ca(2+)-free solution. Twenty nanomolar of U46619 induced contraction and elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)), which were consisted of two phases; slowly developing first phase followed by quickly rising second phase. The second phase was inhibited by verapamil, and all the [Ca(2+)](i) response was abolished in Ca(2+)-free solution. The contraction and [Ca(2+)](i) elevation induced by 20 nM U46619 were not inhibited by U73122, an inhibitor of phosphatidylinositol-specific phospholipase C, or GF109203X, a protein kinase C inhibitor, but were abolished by D609, an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC). However, D609 had no effect on those induced by 1 μM phenylephrine. The U46619-induced responses were also partially inhibited by cation channel blockers, 2-APB and LOE908. The inhibition by LOE908 was abolished in the presence of verapamil, suggesting that LOE908-sensitive cation channels lead to the activation of VDCC by depolarizing plasma membrane. In contrast, 2-APB further diminished the U46619-induced [Ca(2+)](i) elevation in the presence of verapamil. In conclusion, TP receptor stimulation is suggested to be coupled with PC-PLC. Diacylglycerol produced by PC-PLC seems to activate two types of cation channels independently of PKC, which in turn leads to VDCC-dependent and independent Ca(2+) influx, thereby eliciting contraction.
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Affiliation(s)
- Kimiaki Suzuki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422-8526, Japan
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Guo RW, Yang LX, Li MQ, Pan XH, Liu B, Deng YL. Stim1- and Orai1-mediated store-operated calcium entry is critical for angiotensin II-induced vascular smooth muscle cell proliferation. Cardiovasc Res 2011; 93:360-70. [PMID: 22108917 DOI: 10.1093/cvr/cvr307] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
AIM Despite the fact that angiotensin (Ang) II is a critical regulator of the proliferation and migration of vascular smooth muscle cells (VSMCs), the effect of Ang II on VSMC proliferation has remained unclear. In this study, we determined whether Stim1- and Orai1-mediated store-operated calcium (Ca(2+)) entry (SOCE) plays a critical role in Ang II-induced VSMC proliferation and Ang II-accelerated neointimal growth after balloon injury of rat carotid arteries. METHODS AND RESULTS Knockdown of Stim1 and Orai1, putative calcium sensors/modulators, suppressed Ang II-mediated Ca(2+) entry and cell proliferation in synthetic VSMCs. Stim1 and Orai1 short interfering RNAs (siRNAs) decreased neointimal growth induced by Ang II in balloon-injured rat carotid arteries. Ang II significantly increased the expression of Stim1 and Orai1 in neointima. In addition, our results showed that receptor subtype-1 (AT1) significantly contributed to Ang II-induced Ca(2+) entry and proliferation of synthetic VSMCs. However, we found that transient receptor potential canonical 1 (Trpc1) had no effect on Ang II-induced SOCE or cell proliferation of synthetic VSMCs. CONCLUSIONS We show for the first time that Stim1- and Orai1-mediated SOCE may be critical for Ang II-induced VSMC proliferation. This provides important information with respect to targeting cardiovascular diseases under the enhanced renin-Ang system.
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Affiliation(s)
- Rui-wei Guo
- Department of Cardiology, Kunming General Hospital of Chengdu Military Area, Yunnan 650032, China
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22
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Yang B, Gwozdz T, Dutko-Gwozdz J, Bolotina VM. Orai1 and Ca2+-independent phospholipase A2 are required for store-operated Icat-SOC current, Ca2+ entry, and proliferation of primary vascular smooth muscle cells. Am J Physiol Cell Physiol 2011; 302:C748-56. [PMID: 22094335 DOI: 10.1152/ajpcell.00312.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) is important for multiple functions of vascular smooth muscle cells (SMC), which, depending of their phenotype, can resemble excitable and nonexcitable cells. Similar to nonexcitable cells, Orai1 was found to mediate Ca(2+)-selective (CRAC-like) current and SOCE in dedifferentiated cultured SMC and smooth muscle-derived cell lines. However, the role of Orai1 in cation-selective store-operated channels (cat-SOC), which are responsible for SOCE in primary SMC, remains unclear. Here we focus on primary SMC, and assess the role of Orai1 and Ca(2+)-independent phospholipase A(2) (iPLA(2)β, or PLA2G6) in activation of cat-SOC current (I(cat-SOC)), SOCE, and SMC proliferation. Using molecular, electrophysiological, imaging, and functional approaches, we demonstrate that molecular knockdown of either Orai1 or iPLA(2)β leads to similar inhibition of the whole cell cat-SOC current and SOCE in primary aortic SMC and results in significant reduction in DNA synthesis and impairment of SMC proliferation. This is the first demonstration that Orai1 and iPLA(2)β are equally important for cat-SOC, SOCE, and proliferation of primary aortic SMC.
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Affiliation(s)
- Bo Yang
- Ion Channel and Calcium Signaling Unit, Boston Univ. School of Medicine, Boston, MA 02118-2393, USA
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Chakraborty S, Berwick ZC, Bartlett PJ, Kumar S, Thomas AP, Sturek M, Tune JD, Obukhov AG. Bromoenol lactone inhibits voltage-gated Ca2+ and transient receptor potential canonical channels. J Pharmacol Exp Ther 2011; 339:329-40. [PMID: 21795434 DOI: 10.1124/jpet.111.183673] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca(2+) influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca(2+)-independent phospholipase A(2) (iPLA(2))-dependent store-operated Ca(2+) influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA(2), inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca(2+) (Ca(V)1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ∼34% of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that Ca(V)1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed Ca(V)1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited Ca(V)1.2, TRPC5, TRPC6, and heteromeric TRPC1-TRPC5 channels in an iPLA(2)-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K(+) channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA(2)-dependent store-operated Ca(2+) influx channels and iPLA(2)-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate Ca(V)1.2 channels and to regulate vascular tone.
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Affiliation(s)
- Saikat Chakraborty
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indiana University-Purdue University Indianapolis, 635 Barnhill Dr., MS360A, Indianapolis, IN 46202, USA
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Hopson KP, Truelove J, Chun J, Wang Y, Waeber C. S1P activates store-operated calcium entry via receptor- and non-receptor-mediated pathways in vascular smooth muscle cells. Am J Physiol Cell Physiol 2011; 300:C919-26. [PMID: 21270296 PMCID: PMC3074633 DOI: 10.1152/ajpcell.00350.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
Abstract
Sphingosine-1-phosphate (S1P) has been shown to modulate intracellular Ca(2+) through both G protein-coupled receptors and intracellular second messenger pathways. The precise mechanism by which S1P activates store-operated calcium entry (SOCE) in vascular smooth muscle cells (VSMCs) has not been fully characterized. Because sphingolipids and Ca(2+) modulate proliferation and constriction in VSMCs, characterizing the connection between S1P and SOCE may provide novel therapeutic targets for vascular diseases. We found that S1P triggered STIM1 puncta formation and SOCE in VSMCs. S1P-activated SOCE was inhibited by 2-aminoethoxydiphenyl borate (2-APB), diethylstilbestrol (DES), and gadolinium (Gd(3+)). SOCE was observed in VSMCs lacking either S1P(2) or S1P(3) receptors, suggesting that S1P acts via multiple signaling pathways. Indeed, both extracellular and intracellular S1P application increased the total internal reflection fluorescence signal in VSMCs cells transfected with STIM1-yellow fluorescent protein in a 2-APB-sensitive manner. These data, and the fact that 2-APB, DES, and Gd(3+) all inhibited S1P-induced cerebral artery constriction, suggest that SOCE modulates S1P-induced vasoconstriction in vivo. Finally, S1P-induced SOCE was larger in proliferative than in contractile VSMCs, correlating with increases in STIM1, Orai1, S1P(1), and S1P(3) receptor mRNA. These data demonstrate that S1P can act through both receptors and a novel intracellular pathway to activate SOCE. Because S1P-induced SOCE contributes to vessel constriction and is increased in proliferative VSMCs, it is likely that S1P/SOCE signaling in proliferative VSMCs may play a role in vascular dysfunction such as atherosclerosis and diabetes.
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Affiliation(s)
- Kristen Park Hopson
- Stroke and Neurovascular Regulation Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, USA
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Emter CA, Bowles DK. Store-operated Ca(2+) entry is not essential for PDGF-BB induced phenotype modulation in rat aortic smooth muscle. Cell Calcium 2010; 48:10-8. [PMID: 20619453 DOI: 10.1016/j.ceca.2010.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/12/2010] [Accepted: 06/08/2010] [Indexed: 12/15/2022]
Abstract
Suppression of smooth muscle cell (SMC) differentiation marker genes is central to SMC phenotype modulation during vasculo-proliferative diseases such as atherosclerosis and restenosis. Upregulation of the intermediate-conductance Ca(2+)-activated K(+) channel (K(Ca)3.1) is integral for mitogen-induced suppression of SMC marker genes and post-angioplasty restenosis. Modulation of SMC marker gene expression has been observed following Ca(2+) influx from multiple sources, however, it is unknown whether upregulation of K(Ca)3.1 and/or suppression of SMC differentiation genes is dependent on a Ca(2+) mediated mechanism. The purpose of this study was to determine the dependence of mitogen-induced SMC phenotype modulation on store-operated Ca(2+) entry (SOCE). In growth-arrested, differentiated rat aortic SMCs, platelet-derived growth factor-BB (PDGF-BB) augmented SOCE. However, PDGF-BB induced upregulation of K(Ca)3.1 and downregulation of the SMC marker gene smooth muscle myosin heavy chain (SMMHC) and myocardin was not dependent on SOCE. Co-treatment with the iPLA2 inhibitor bromoenol lactone (BEL) inhibited the effects of PDGF-BB on SMC phenotype modulation and SOCE. Our results indicate SOCE is not required for PDGF-BB induced phenotype modulation in rat aortic SMCs. Rather, we implicate a novel BEL-sensitive mechanism which regulates both SOCE and phenotype modulation, independently.
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Affiliation(s)
- Craig A Emter
- Department of Biomedical Science, University of Missouri-Columbia, 1600 E. Rollins, W160 Veterinary Medicine, Columbia, MO 65211, United States.
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Zhang Y, Wang QL, Zhan YZ, Duan HJ, Cao YJ, He LC. Role of store-operated calcium entry in imperatorin-induced vasodilatation of rat small mesenteric artery. Eur J Pharmacol 2010; 647:126-31. [PMID: 20813104 DOI: 10.1016/j.ejphar.2010.08.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 06/26/2010] [Accepted: 08/12/2010] [Indexed: 12/28/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) has recently been proposed to contribute to Ca(2+) influx in vascular smooth muscle cells (VSMCs). Imperatorin is known for its potent vasodilatory effects as a dietary furanocoumarin. The study was designed to examine the hypothesis that SOCE have a functional role in imperatorin-induced vasodilation. Small mesenteric resistance arteries and mesenteric VSMCs were obtained from rats. Isometric tensions of isolated artery rings were measured by a sensitive myograph system. Laser scanning confocal microscopy was used to determine the intracellular Ca(2+) concentration of fluo-3-loaded VSMCs. Imperatorin (1-100 μM) relaxed artery rings precontracted by phenylephrine in a concentration-dependent manner. In cultured mesenteric VSMCs, passive store depletion by thapsigargin and active store depletion by phenylephrine both induced Ca(2+) influx due to SOCE. Imperatorin didn't inhibit SOCE-mediated increases in cytosolic Ca(2+) levels evoked by the emptying of the stores. In isolated artery rings, imperatorin didn't inhibit SOCE-induced contractions due to store depletion. Our results exclude SOCE mechanism of vasodilatation by imperatorin. But imperatorin is partly similar with nifedipine in vasorelaxation effect.
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Affiliation(s)
- Yan Zhang
- School of Medicine, Xi'an Jiaotong University, Xi'an, PR China
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Basselin M, Rosa AO, Ramadan E, Cheon Y, Chang L, Chen M, Greenstein D, Wohltmann M, Turk J, Rapoport SI. Imaging decreased brain docosahexaenoic acid metabolism and signaling in iPLA(2)β (VIA)-deficient mice. J Lipid Res 2010; 51:3166-73. [PMID: 20686114 DOI: 10.1194/jlr.m008334] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ca(2+)-independent phospholipase A(2)β (iPLA(2)β) selectively hydrolyzes docosahexaenoic acid (DHA, 22:6n-3) in vitro from phospholipid. Mutations in the PLA2G6 gene encoding this enzyme occur in patients with idiopathic neurodegeneration plus brain iron accumulation and dystonia-parkinsonism without iron accumulation, whereas mice lacking PLA2G6 show neurological dysfunction and neuropathology after 13 months. We hypothesized that brain DHA metabolism and signaling would be reduced in 4-month-old iPLA(2)β-deficient mice without overt neuropathology. Saline or the cholinergic muscarinic M(1,3,5) receptor agonist arecoline (30 mg/kg) was administered to unanesthetized iPLA(2)β(-/-), iPLA(2)β(+/-), and iPLA(2)β(+/+) mice, and [1-(14)C]DHA was infused intravenously. DHA incorporation coefficients k* and rates J(in), representing DHA metabolism, were determined using quantitative autoradiography in 81 brain regions. iPLA(2)β(-/-) or iPLA(2)β(+/-) compared with iPLA(2)β(+/+) mice showed widespread and significant baseline reductions in k* and J(in) for DHA. Arecoline increased both parameters in brain regions of iPLA(2)β(+/+) mice but quantitatively less so in iPLA(2)β(-/-) and iPLA(2)β(+/-) mice. Consistent with iPLA(2)β's reported ability to selectively hydrolyze DHA from phospholipid in vitro, iPLA(2)β deficiency reduces brain DHA metabolism and signaling in vivo at baseline and following M(1,3,5) receptor activation. Positron emission tomography might be used to image disturbed brain DHA metabolism in patients with PLA2G6 mutations.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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Ramadan E, Rosa AO, Chang L, Chen M, Rapoport SI, Basselin M. Extracellular-derived calcium does not initiate in vivo neurotransmission involving docosahexaenoic acid. J Lipid Res 2010; 51:2334-40. [PMID: 20388940 PMCID: PMC2903827 DOI: 10.1194/jlr.m006262] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/13/2010] [Indexed: 11/20/2022] Open
Abstract
In vitro studies show that docosahexaenoic acid (DHA) can be released from membrane phospholipid by Ca(2+)-independent phospholipase A(2) (iPLA(2)), Ca(2+)-independent plasmalogen PLA(2) or secretory PLA(2 (sPLA2)), but not by Ca(2+)-dependent cytosolic PLA(2) (cPLA2), which selectively releases arachidonic acid (AA). Since glutamatergic NMDA (N-methyl-D-aspartate) receptor activation allows extracellular Ca(2+) into cells, we hypothesized that brain DHA signaling would not be altered in rats given NMDA, to the extent that in vivo signaling was mediated by Ca(2+)-independent mechanisms. Isotonic saline, a subconvulsive dose of NMDA (25 mg/kg), MK-801, or MK-801 followed by NMDA was administered i.p. to unanesthetized rats. Radiolabeled DHA or AA was infused intravenously and their brain incorporation coefficients k*, measures of signaling, were imaged with quantitative autoradiography. NMDA or MK-801 compared with saline did not alter k* for DHA in any of 81 brain regions examined, whereas NMDA produced widespread and significant increments in k* for AA. In conclusion, in vivo brain DHA but not AA signaling via NMDA receptors is independent of extracellular Ca(2+) and of cPLA(2). DHA signaling may be mediated by iPLA(2), plasmalogen PLA(2), or other enzymes insensitive to low concentrations of Ca(2+). Greater AA than DHA release during glutamate-induced excitotoxicity could cause brain cell damage.
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Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
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Courtois A, Andujar P, Ladeiro Y, Ducret T, Rogerieux F, Lacroix G, Baudrimont I, Guibert C, Roux E, Canal-Raffin M, Brochard P, Marano F, Marthan R, Muller B. Effect of engineered nanoparticles on vasomotor responses in rat intrapulmonary artery. Toxicol Appl Pharmacol 2010; 245:203-10. [DOI: 10.1016/j.taap.2010.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 02/26/2010] [Accepted: 03/01/2010] [Indexed: 10/19/2022]
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Dietrich HH, Abendschein DR, Moon SH, Nayeb-Hashemi N, Mancuso DJ, Jenkins CM, Kaltenbronn KM, Blumer KJ, Turk J, Gross RW. Genetic ablation of calcium-independent phospholipase A(2)beta causes hypercontractility and markedly attenuates endothelium-dependent relaxation to acetylcholine. Am J Physiol Heart Circ Physiol 2010; 298:H2208-20. [PMID: 20382858 DOI: 10.1152/ajpheart.00839.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of phospholipases leads to the release of arachidonic acid and lysophospholipids that play prominent roles in regulating vasomotor tone. To identify the role of calcium-independent phospholipase A(2)beta (iPLA(2)beta) in vasomotor function, we measured vascular responses to phenylephrine (PE) and ACh in mesenteric arterioles from wild-type (WT; iPLA(2)beta(+/+)) mice and those lacking the beta-isoform (iPLA(2)beta(-/-)) both ex vivo and in vivo. Vessels isolated from iPLA(2)beta(-/-) mice demonstrated increased constriction to PE, despite lower basal smooth muscle calcium levels, and decreased vasodilation to ACh compared with iPLA(2)beta(+/+) mice. PE constriction resulted in initial intracellular calcium release with subsequent steady-state constriction that depended on extracellular calcium influx. Endothelial denudation had no effect on vessel tone or PE-induced constriction although the dilation to ACh was significantly reduced in iPLA(2)beta(+/+) vessels. In contrast, vessels from iPLA(2)beta(-/-) constricted by 54% after denudation, indicating smooth muscle hypercontractility. In vivo, blood pressure, resting vessel diameter, and constriction of mesenteric vessels to PE were not different in iPLA(2)beta(-/-) vessels compared with WT mouse vessels. However, relaxation after ACh administration in situ was attenuated, indicating an endothelial inability to induce dilation in response to ACh. In cultured endothelial cells, inhibition of iPLA(2)beta with (S)-(E)-6-(bromomethylene)tetrahydro-3-(1-naphthalenyl)-2H-pyran-2-one (BEL) decreased endothelial nitric oxide synthase phosphorylation and reduced endothelial agonist-induced intracellular calcium release as well as extracellular calcium influx. We conclude that iPLA(2)beta is an important mediator of vascular relaxation and intracellular calcium homeostasis in both smooth muscle and endothelial cells and that ablation of iPLA(2)beta causes agonist-induced smooth muscle hypercontractility and reduced agonist-induced endothelial dilation.
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Affiliation(s)
- Hans H Dietrich
- Washington Univ. School of Medicine, Dept. of Neurosurgery, 660 South Euclid Ave., Campus Box 8057, St. Louis, MO 63110, USA.
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Abstract
TRP (transient receptor potential) channels play important roles in the regulation of normal and pathological cellular function. In the vasculature, TRP channels are present both in ECs (endothelial cells) and vascular SMCs (smooth muscle cells) and contribute to vasomotor control mechanisms in most vascular beds. Vascular TRP channels are activated by various stimuli, such as mechanical perturbation, receptor activation and dietary molecules. Some of the specific roles of these channels in normal and impaired vascular function have emerged in recent years and include participation in vascular signalling processes, such as neurotransmission, hormonal signalling, NO production, myogenic tone and autoregulation of blood flow, thermoregulation, responses to oxidative stress and cellular proliferative activity. Current research is aimed at understanding the interactions of TRP channels with other vascular proteins and signalling mechanisms. These studies should reveal new targets for pharmacological therapy of vascular diseases, such as hypertension, ischaemia and vasospasm, and vascular proliferative states.
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Wong MSK, Man RYK, Vanhoutte PM. Calcium-independent phospholipase A(2) plays a key role in the endothelium-dependent contractions to acetylcholine in the aorta of the spontaneously hypertensive rat. Am J Physiol Heart Circ Physiol 2010; 298:H1260-6. [PMID: 20118407 DOI: 10.1152/ajpheart.01068.2009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phospholipase A(2) (PLA(2)), a regulatory enzyme found in most mammalian cells, catalyzes the breakdown of membrane phospholipids to arachidonic acid. There are two major cytosolic types of the enzyme, calcium-dependent (cPLA(2)) and calcium-independent (iPLA(2)) PLA(2). The present study investigated whether or not iPLA(2) plays a role in the endothelium-dependent contractions of the aorta of the spontaneously hypertensive rat and its normotensive counterpart, the Wistar-Kyoto rat. The presence of iPLA(2) in the endothelial cells was identified by using immunochemistry and immunoblotting. Aortic rings with and without the endothelium were suspended in organ chambers for isometric tension recording. The production of prostanoids was measured by using enzyme immunoassay kits. iPLA(2) was densely distributed in endothelial cells of the aorta of both strains. At 3 x 10(-6) M, the selective iPLA(2) inhibitor, bromoenol lactone (BEL), abrogated endothelium-dependent contractions induced by acetylcholine but not those evoked by the calcium ionophore A-23187. The effects of BEL were similar in the aortae of Wistar-Kyoto and spontaneously hypertensive rats. The nonselective PLA(2) inhibitor quinacrine abolished the contractions triggered by both acetylcholine and A-23187, whereas the store-operated calcium channel inhibitor SKF-96365 prevented only the acetylcholine-induced contraction. The acetylcholine- but not the A-23187-induced release of 6-keto prostaglandin F(1alpha) was inhibited by BEL. The release of thromboxane B(2) by either acetylcholine or A-23187 was not affected by BEL. In conclusion, iPLA(2) plays a substantial role in the generation of endothelium-derived contracting factor evoked by acetylcholine.
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Affiliation(s)
- Michael S K Wong
- Dept. of Pharmacology and Pharmacy, Univ. of Hong Kong, Hong Kong
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Xie Z, Gong MC, Su W, Xie D, Turk J, Guo Z. Role of calcium-independent phospholipase A2beta in high glucose-induced activation of RhoA, Rho kinase, and CPI-17 in cultured vascular smooth muscle cells and vascular smooth muscle hypercontractility in diabetic animals. J Biol Chem 2010; 285:8628-38. [PMID: 20086008 DOI: 10.1074/jbc.m109.057711] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Previous studies suggest that high glucose-induced RhoA/Rho kinase/CPI-17 activation is involved in diabetes-associated vascular smooth muscle hypercontractility. However, the upstream signaling that links high glucose and RhoA/Rho kinase/CPI-17 activation is unknown. Here we report that calcium-independent phospholipase A(2)beta (iPLA(2)beta) is required for high glucose-induced RhoA/Rho kinase/CPI-17 activation and thereby contributes to diabetes-associated vascular smooth muscle hypercontractility. We demonstrate that high glucose increases iPLA(2)beta mRNA, protein, and iPLA(2) activity in a time-dependent manner. Protein kinase C is involved in high glucose-induced iPLA(2)beta protein up-regulation. Inhibiting iPLA(2)beta activity with bromoenol lactone or preventing its expression by genetic deletion abolishes high glucose-induced RhoA/Rho kinase/CPI-17 activation, and restoring expression of iPLA(2)beta in iPLA(2)beta-deficient cells also restores high glucose-induced CPI-17 phosphorylation. Pharmacological and genetic inhibition of 12/15-lipoxygenases has effects on high glucose-induced CPI-17 phosphorylation similar to iPLA(2)beta inhibition. Moreover, increases in iPLA(2) activity and iPLA(2)beta protein expression are also observed in both type 1 and type 2 diabetic vasculature. Pharmacological and genetic inhibition of iPLA(2)beta, but not iPLA(2)gamma, diminishes diabetes-associated vascular smooth muscle hypercontractility. In summary, our results reveal a novel mechanism by which high glucose-induced, protein kinase C-mediated iPLA(2)beta up-regulation activates the RhoA/Rho kinase/CPI-17 via 12/15-lipoxygenases and thereby contributes to diabetes-associated vascular smooth muscle hypercontractility.
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Affiliation(s)
- Zhongwen Xie
- Department of Physiology, University of Kentucky School of Medicine, Lexington, Kentucky 40536, USA
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Lei X, Barbour SE, Ramanadham S. Group VIA Ca2+-independent phospholipase A2 (iPLA2beta) and its role in beta-cell programmed cell death. Biochimie 2010; 92:627-37. [PMID: 20083151 DOI: 10.1016/j.biochi.2010.01.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 01/11/2010] [Indexed: 01/09/2023]
Abstract
Activation of phospholipases A(2) (PLA(2)s) leads to the generation of biologically active lipid mediators that can affect numerous cellular events. The Group VIA Ca(2+)-independent PLA(2), designated iPLA(2)beta, is active in the absence of Ca(2+), activated by ATP, and inhibited by the bromoenol lactone suicide inhibitor (BEL). Over the past 10-15 years, studies using BEL have demonstrated that iPLA(2)beta participates in various biological processes and the recent availability of mice in which iPLA(2)beta expression levels have been genetically-modified are extending these findings. Work in our laboratory suggests that iPLA(2)beta activates a unique signaling cascade that promotes beta-cell apoptosis. This pathway involves iPLA(2)beta dependent induction of neutral sphingomyelinase, production of ceramide, and activation of the intrinsic pathway of apoptosis. There is a growing body of literature supporting beta-cell apoptosis as a major contributor to the loss of beta-cell mass associated with the onset and progression of Type 1 and Type 2 diabetes mellitus. This underscores a need to gain a better understanding of the molecular mechanisms underlying beta-cell apoptosis so that improved treatments can be developed to prevent or delay the onset and progression of diabetes mellitus. Herein, we offer a general review of Group VIA Ca(2+)-independent PLA(2) (iPLA(2)beta) followed by a more focused discussion of its participation in beta-cell apoptosis. We suggest that iPLA(2)beta-derived products trigger pathways which can lead to beta-cell apoptosis during the development of diabetes.
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Affiliation(s)
- Xiaoyong Lei
- Department of Medicine, Mass Spectrometry Resource and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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Coupled calcium and zinc dyshomeostasis and oxidative stress in cardiac myocytes and mitochondria of rats with chronic aldosteronism. J Cardiovasc Pharmacol 2009; 53:414-23. [PMID: 19333130 DOI: 10.1097/fjc.0b013e3181a15e77] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A dyshomeostasis of extra- and intracellular Ca(2+) and Zn(2+) occurs in rats receiving chronic aldosterone/salt treatment (ALDOST). Herein, we hypothesized that the dyshomeostasis of intracellular Ca(2+) and Zn(2+) is intrinsically coupled that alters the redox state of cardiac myocytes and mitochondria, with Ca(2+) serving as a pro-oxidant and Zn(2+) as an antioxidant. Toward this end, we harvested hearts from rats receiving 4 weeks of ALDOST alone or cotreatment with either spironolactone (Spiro), an aldosterone receptor antagonist, or amlodipine (Amlod), an L-type Ca(2+) channel blocker, and from age/sex-matched untreated controls. In each group, we monitored cardiomyocyte [Ca(2+)]i and [Zn(2+)]i and mitochondrial [Ca(2+)]m and [Zn(2+)]m; biomarkers of oxidative stress and antioxidant defenses; expression of Zn transporters, Zip1 and ZnT-1; metallothionein-1, a Zn(2+)-binding protein; and metal response element transcription factor-1, a [Zn(2+)]i sensor and regulator of antioxidant defenses. Compared with controls, at 4-week ALDOST, we found the following: (a) increased [Ca(2+)]i and [Zn(2+)]i, together with increased [Ca(2+)]m and [Zn(2+)]m, each of which could be prevented by Spiro and attenuated with Amlod; (b) increased levels of 3-nitrotyrosine and 4-hydroxy-2-nonenal in cardiomyocytes, together with increased H(2)O(2) production, malondialdehyde, and oxidized glutathione in mitochondria that were coincident with increased activities of Cu/Zn superoxide dismutase and glutathione peroxidase; and (c) increased expression of metallothionein-1, Zip1 and ZnT-1, and metal response element transcription factor-1, attenuated by Spiro. Thus, an intrinsically coupled dyshomeostasis of intracellular Ca(2+) and Zn(2+) occurs in cardiac myocytes and mitochondria in rats receiving ALDOST, where it serves to alter their redox state through a respective induction of oxidative stress and generation of antioxidant defenses. The importance of therapeutic strategies that can uncouple these two divalent cations and modulate their ratio in favor of sustained antioxidant defenses is therefore suggested.
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Wang S, Zhang Y, Wier WG, Yu X, Zhao M, Hu H, Sun L, He X, Wang Y, Wang B, Zang W. Role of store-operated Ca(2+) entry in adenosine-induced vasodilatation of rat small mesenteric artery. Am J Physiol Heart Circ Physiol 2009; 297:H347-54. [PMID: 19429831 DOI: 10.1152/ajpheart.00060.2009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) has recently been proposed to contribute to Ca(2+) influx in vascular smooth muscle cells (VSMCs). Adenosine is known for its protective role against hypoxia and ischemia by increasing nutrient and oxygen supply through vasodilation. This study was designed to examine the hypothesis that SOCE have a functional role in adenosine-induced vasodilation. Small mesenteric resistance arteries and mesenteric VSMCs were obtained from rats. Isometric tensions of isolated artery rings were measured by a sensitive myograph system. Laser-scanning confocal microscopy was used to determine the intracellular Ca(2+) concentration of fluo 3-loaded VSMCs. Adenosine (0.1-100 microM) relaxed artery rings that were precontracted by phenylephrine in a concentration-dependent manner. In cultured mesenteric VSMCs, passive store depletion by thapsigargin and active store depletion by phenylephrine both induced Ca(2+) influx due to SOCE. Adenosine inhibited SOCE-mediated increases in cytosolic Ca(2+) levels evoked by the emptying of the stores. In isolated artery rings, adenosine inhibited SOCE-induced contractions due to store depletion. A(2A) receptor antagonism with SCH-58261 and adenylate cyclase inhibition with SQ-22536 largely attenuated adenosine responses. The cAMP analog 8-bromo-cAMP mimicked the effects of adenosine on SOCE. Our results indicate a novel mechanism of vasodilatation by adenosine that involves regulation of SOCE through the cAMP signaling pathway due to activation of adenosine A(2A) receptors.
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Affiliation(s)
- Shengpeng Wang
- Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an, PR China
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Johnson CD, Melanaphy D, Purse A, Stokesberry SA, Dickson P, Zholos AV. Transient receptor potential melastatin 8 channel involvement in the regulation of vascular tone. Am J Physiol Heart Circ Physiol 2009; 296:H1868-77. [PMID: 19363131 DOI: 10.1152/ajpheart.01112.2008] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transient receptor potential melastatin 8 (TRPM8) channel has been characterized as a cold and menthol receptor expressed in a subpopulation of sensory neurons but was recently identified in other tissues, including the respiratory tract, urinary system, and vasculature. Thus TRPM8 may play multiple functional roles, likely to be in a tissue- and activation state-dependent manner. We examined the TRPM8 channel presence in large arteries from rats and the functional consequences of their activation. We also aimed to examine whether these channels contribute to control of conscious human skin blood flow. TRPM8 mRNA and protein were detected in rat tail, femoral and mesenteric arteries, and thoracic aorta. This was confirmed in single isolated vascular myocytes by immunocytochemistry. Isometric contraction studies on endothelium-denuded relaxed rat vessels found small contractions on application of the TRPM8-specific agonist menthol (300 microM). However, both menthol and another agonist icilin (50 microM) caused relaxation of vessels precontracted with KCl (60 mM) or the alpha-adrenoceptor agonist phenylephrine (2 microM) and a reduction in sympathetic nerve-mediated contraction. These effects were antagonized by bromoenol lactone treatment, suggesting the involvement of Ca(2+)-independent phospholipase A(2) activation in TRPM8-mediated vasodilatation. In thoracic aorta with intact endothelium, menthol-induced inhibition of KCl-induced contraction was enhanced. This was unaltered by preincubation with either N(omega)-nitro-l-arginine methyl ester (l-NAME; 100 nM), a nitric oxide synthase inhibitor, or the ACh receptor antagonist atropine (1 microM). Application of menthol (3% solution, topical application) to skin caused increased blood flow in conscious humans, as measured by laser Doppler fluximetry. Vasodilatation was markedly reduced or abolished by prior application of l-NAME (passive application, 10 mM) or atropine (iontophoretic application, 100 nM, 30 s at 70 microA). We conclude that TRPM8 channels are present in rat artery vascular smooth muscle and on activation cause vasoconstriction or vasodilatation, dependent on previous vasomotor tone. TRPM8 channels may also contribute to human cutaneous vasculature control, likely with the involvement of additional neuronal mechanisms.
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Affiliation(s)
- Christopher D Johnson
- Cardiovascular Biomedical Research Centre, School of Medicine, Dentistry and Biomedical Sciences, Medical Biology Centre, Queen's University of Belfast, Belfast, UK, BT9 7BL.
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Guo RW, Wang H, Gao P, Li MQ, Zeng CY, Yu Y, Chen JF, Song MB, Shi YK, Huang L. An essential role for stromal interaction molecule 1 in neointima formation following arterial injury. Cardiovasc Res 2008; 81:660-8. [PMID: 19052075 DOI: 10.1093/cvr/cvn338] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
AIMS There is evidence to suggest that stromal interaction molecule 1 (STIM1) functions as a Ca2+ sensor on the endoplasmic reticulum, leading to transduction of signals to the plasma membrane and opening of store-operated Ca2+ channels (SOC). SOC have been detected in vascular smooth muscle cells (VSMCs) and are thought to have an essential role in the regulation of contraction and cell proliferation. We hypothesized that knockdown of STIM1 inhibits VSMC proliferation and suppresses neointimal hyperplasia. METHODS AND RESULTS We examined the effect of the knockdown of STIM1 using a rat balloon injury model and cultured rat aortic VSMCs. Interestingly, knockdown of rat STIM1 by adenovirus delivery of small interfering RNA (siRNA) significantly suppressed neointimal hyperplasia in a rat carotid artery balloon injury model at 14 days after injury. The re-expression of human STIM1 to smooth muscle reversed the effect of STIM1 knockdown on neointimal formation. Rat aortic VSMCs were used for the in vitro assays. Knockdown of endogenous STIM1 significantly inhibited proliferation and migration of VSMCs. Moreover, STIM1 knockdown induced cell-cycle arrest in G0/G1 and resulted in a marked decrease in SOC. Replenishment with recombinant human STIM1 reversed the effect of siRNA knockdown. These results suggest STIM1 has a critical role in neointimal formation in a rat model of vascular injury. CONCLUSION STIM1 may represent a novel therapeutic target in the prevention of restenosis after vascular interventions.
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Affiliation(s)
- Rui-Wei Guo
- Department of Cardiology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
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Boittin FX, Gribi F, Serir K, Bény JL. Ca2+-independent PLA2 controls endothelial store-operated Ca2+ entry and vascular tone in intact aorta. Am J Physiol Heart Circ Physiol 2008; 295:H2466-74. [PMID: 18952717 DOI: 10.1152/ajpheart.00639.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During an agonist stimulation of endothelial cells, the sustained Ca2+ entry occurring through store-operated channels has been shown to significantly contribute to smooth muscle relaxation through the release of relaxing factors such as nitric oxide (NO). However, the mechanisms linking Ca2+ stores depletion to the opening of such channels are still elusive. We have used Ca2+ and tension measurements in intact aortic strips to investigate the role of the Ca2+-independent isoform of phospholipase A2 (iPLA2) in endothelial store-operated Ca2+ entry and endothelium-dependent relaxation of smooth muscle. We provide evidence that iPLA2 is involved in the activation of endothelial store-operated Ca2+ entry when Ca2+ stores are artificially depleted. We also show that the sustained store-operated Ca2+ entry occurring during physiological stimulation of endothelial cells with the circulating hormone ATP is due to iPLA2 activation and significantly contributes to the amplitude and duration of ATP-induced endothelium-dependent relaxation. Consistently, both iPLA2 metabolites arachidonic acid and lysophosphatidylcholine were found to stimulate Ca2+ entry in native endothelial cells. However, only the latter triggered endothelium-dependent relaxation through NO release, suggesting that lysophosphatidylcholine produced by iPLA2 upon Ca2+ stores depletion may act as an intracellular messenger that stimulates store-operated Ca2+ entry and subsequent NO production in endothelial cells. Finally, we found that ACh-induced endothelium relaxation also depends on iPLA2 activation, suggesting that the iPLA2-dependent control of endothelial store-operated Ca2+ entry is a key physiological mechanism regulating arterial tone.
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Affiliation(s)
- François-Xavier Boittin
- Department of Zoology and Animal Biology, Laboratory of Vascular Cell Physiology, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
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Saleh SN, Albert AP, Peppiatt-Wildman CM, Large WA. Diverse properties of store-operated TRPC channels activated by protein kinase C in vascular myocytes. J Physiol 2008; 586:2463-76. [PMID: 18356201 DOI: 10.1113/jphysiol.2008.152157] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In vascular smooth muscle, store-operated channels (SOCs) contribute to many physiological functions including vasoconstriction and cell growth and proliferation. In the present work we compared the properties of SOCs in freshly dispersed myocytes from rabbit coronary and mesenteric arteries and portal vein. Cyclopiazonic acid (CPA)-induced whole-cell SOC currents were sixfold greater at negative membrane potentials and displayed markedly different rectification properties and reversal potentials in coronary compared to mesenteric artery myocytes. Single channel studies showed that endothelin-1, CPA and the cell-permeant Ca(2+) chelator BAPTA-AM activated the same 2.6 pS SOC in coronary artery. In 1.5 mM [Ca(2+)](o) the unitary conductance of SOCs was significantly greater in coronary than in mesenteric artery. Moreover in 0 mM [Ca(2+)](o) the conductance of SOCs in coronary artery was unaltered whereas the conductance of SOCs in mesenteric artery was increased fourfold. In coronary artery SOCs were inhibited by the protein kinase C (PKC) inhibitor chelerythrine and activated by the phorbol ester phorbol 12,13-dibutyrate (PDBu), the diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) and a catalytic subunit of PKC. These data infer an important role for PKC in activation of SOCs in coronary artery similar to mesenteric artery and portal vein. Anti-TRPC1 and -TRPC5 antibodies inhibited SOCs in coronary and mesenteric arteries and portal vein but anti-TRPC6 blocked SOCs only in coronary artery and anti-TRPC7 blocked SOCs only in portal vein. Immunoprecipitation showed associations between TRPC1 and TRPC5 in all preparations but between TRPC5 and TRPC6 only in coronary artery and between TRPC5 and TRPC7 only in portal vein. Finally, flufenamic acid increased SOC activity in coronary artery but inhibited SOCs in mesenteric artery and portal vein myocytes. These data provide strong evidence that vascular myocytes express diverse SOC isoforms, which are likely to be composed of different TRPC proteins and have different physiological functions.
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Affiliation(s)
- Sohag N Saleh
- Ion Channels and Cell Signalling Research Centre, Division of Basic Medical Sciences, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK
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