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Tamang HK, Yang R, Song Z, Hsu S, Peng C, Tung Y, Tzeng B, Chen C. Ca v 3.2 T-type calcium channel regulates mouse platelet activation and arterial thrombosis. J Thromb Haemost 2022; 20:1887-1899. [PMID: 35490411 PMCID: PMC9541131 DOI: 10.1111/jth.15745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cav 3.2 is a T-type calcium channel that causes low-threshold exocytosis. T-type calcium channel blockers reduce platelet granule exocytosis and aggregation. However, studies of the T-type calcium channel in platelets are lacking. OBJECTIVE To examine the expression and role of Cav 3.2 in platelet function. METHODS Global Cav 3.2-/- and platelet-specific Cav 3.2-/- mice and littermate controls were used for this study. Western blot analysis was used to detect the presence of Cav 3.2 and activation of the calcium-responsive protein extracellular signal-regulated kinase (ERK). Fura-2 dye was used to assess platelet calcium. Flow cytometry and light transmission aggregometry were used to evaluate platelet activation markers and aggregation, respectively. FeCl3 -induced thrombosis and a microfluidic flow device were used to assess in vivo and ex vivo thrombosis, respectively. RESULTS Cav 3.2 was expressed in mouse platelets. As compared with wild-type controls, Cav 3.2-/- mouse platelets showed reduced calcium influx. Similarly, treatment with the T-type calcium channel inhibitor Ni2+ decreased the calcium influx in wild-type platelets. As compared with controls, both Cav 3.2-/- and Ni2+ -treated wild-type platelets showed reduced activation of ERK. ATP release, P-selectin exposure, and αIIb β3 activation were reduced in Cav 3.2-/- and Ni2+ -treated wild-type platelets, as was platelet aggregation. On in vivo and ex vivo thrombosis assay, Cav3.2 deletion caused delayed thrombus formation. However, tail bleeding assay showed intact hemostasis. CONCLUSION These results suggest that Cav 3.2 is required for the optimal activation of platelets.
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Affiliation(s)
- Hem Kumar Tamang
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Ruey‐Bing Yang
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Zong‐Han Song
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | - Shao‐Chun Hsu
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
| | | | - Yi‐Chung Tung
- Research Center for Applied SciencesAcademia SinicaTaipeiTaiwan
| | - Bing‐Hsiean Tzeng
- Division of CardiologyFar Eastern Memorial Hospital and Tri‐Service General HospitalNational Defense Medical CenterTaipeiTaiwan
| | - Chien‐Chang Chen
- Taiwan International Graduate Program in Molecular MedicineNational Yang Ming Chiao Tung University and Academia SinicaTaipeiTaiwan
- Institute of Biomedical SciencesAcademia SinicaTaipeiTaiwan
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Zheng Z, Wang X, Wang Y, King JAC, Xie P, Wu S. CaMK4 is a downstream effector of the α 1G T-type calcium channel to determine the angiogenic potential of pulmonary microvascular endothelial cells. Am J Physiol Cell Physiol 2021; 321:C964-C977. [PMID: 34586897 DOI: 10.1152/ajpcell.00216.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/27/2021] [Indexed: 01/25/2023]
Abstract
Pulmonary microvascular endothelial cells (PMVECs) uniquely express an α1G-subtype of voltage-gated T-type Ca2+ channel. We have previously revealed that the α1G channel functions as a background Ca2+ entry pathway that is critical for the cell proliferation, migration, and angiogenic potential of PMVECs, a novel function attributed to the coupling between α1G-mediated Ca2+ entry and constitutive Akt phosphorylation and activation. Despite this significance, mechanism(s) that link the α1G-mediated Ca2+ entry to Akt phosphorylation remain incompletely understood. In this study, we demonstrate that Ca2+/calmodulin-dependent protein kinase (CaMK) 4 serves as a downstream effector of the α1G-mediated Ca2+ entry to promote the angiogenic potential of PMVECs. Notably, CaMK2 and CaMK4 are both expressed in PMVECs. Pharmacological blockade or genetic knockdown of the α1G channel led to a significant reduction in the phosphorylation level of CaMK4 but not the phosphorylation level of CaMK2. Pharmacological inhibition as well as genetic knockdown of CaMK4 significantly decreased cell proliferation, migration, and network formation capacity in PMVECs. However, CaMK4 inhibition or knockdown did not alter Akt phosphorylation status in PMVECs, indicating that α1G/Ca2+/CaMK4 is independent of the α1G/Ca2+/Akt pathway in sustaining the cells' angiogenic potential. Altogether, these findings suggest a novel α1G-CaMK4 signaling complex that regulates the Ca2+-dominated angiogenic potential in PMVECs.
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Affiliation(s)
- Zhen Zheng
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Xuelin Wang
- Department of Respiratory and Critical Care Medicine, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yuxia Wang
- Department of Anesthesiology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Judy A C King
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana
| | - Peilin Xie
- Department of Anesthesiology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Wan L, Wu W, Jiang S, Wan S, Meng D, Wang Z, Zhang J, Wei L, Yu P. Mibefradil and Flunarizine, Two T-Type Calcium Channel Inhibitors, Protect Mice against Lipopolysaccharide-Induced Acute Lung Injury. Mediators Inflamm 2020; 2020:3691701. [PMID: 33223955 PMCID: PMC7671802 DOI: 10.1155/2020/3691701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/04/2020] [Accepted: 10/21/2020] [Indexed: 12/28/2022] Open
Abstract
Recent studies have illuminated that blocking Ca2+ influx into effector cells is an attractive therapeutic strategy for lung injury. We hypothesize that T-type calcium channel may be a potential therapeutic target for acute lung injury (ALI). In this study, the pharmacological activity of mibefradil (a classical T-type calcium channel inhibitor) was assessed in a mouse model of lipopolysaccharide- (LPS-) induced ALI. In LPS challenged mice, mibefradil (20 and 40 mg/kg) dramatically decreased the total cell number, as well as the productions of TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF). Mibefradil also suppressed total protein concentration in BALF, attenuated Evans blue extravasation, MPO activity, and NF-κB activation in lung tissue. Furthermore, flunarizine, a widely prescripted antimigraine agent with potent inhibition on T-type channel, was also found to protect mice against lung injury. These data demonstrated that T-type calcium channel inhibitors may be beneficial for treating acute lung injury. The important role of T-type calcium channel in the acute lung injury is encouraged to be further investigated.
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Affiliation(s)
- Limei Wan
- The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - Weibin Wu
- Department of Basic Medicine, Zhaoqing Medical College, Zhaoqing 526020, China
| | - Shunjun Jiang
- Department of Pharmacy, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Shanhe Wan
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, China
| | - Dongmei Meng
- Department of Pharmacy, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Zhipeng Wang
- Department of Pharmacy, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Jiajie Zhang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, China
| | - Li Wei
- Department of Pharmacy, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Pengjiu Yu
- Department of Pharmacy, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
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4
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Zheng Z, Chen H, Xie P, Dickerson CA, King JAC, Alexeyev MF, Wu S. α 1G T-type calcium channel determines the angiogenic potential of pulmonary microvascular endothelial cells. Am J Physiol Cell Physiol 2019; 316:C353-C364. [PMID: 30649917 DOI: 10.1152/ajpcell.00336.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pulmonary microvascular endothelial cells (PMVECs) display a rapid angioproliferative phenotype, essential for maintaining homeostasis in steady-state and promoting vascular repair after injury. Although it has long been established that endothelial cytosolic Ca2+ ([Ca2+]i) transients are required for proliferation and angiogenesis, mechanisms underlying such regulation and the transmembrane channels mediating the relevant [Ca2+]i transients remain incompletely understood. In the present study, the functional role of the microvascular endothelial site-specific α1G T-type Ca2+ channel in angiogenesis was examined. PMVECs intrinsically possess an in vitro angiogenic "network formation" capacity. Depleting extracellular Ca2+ abolishes network formation, whereas blockade of vascular endothelial growth factor receptor or nitric oxide synthase has little or no effect, suggesting that the network formation is a [Ca2+]i-dependent process. Blockade of the T-type Ca2+ channel or silencing of α1G, the only voltage-gated Ca2+ channel subtype expressed in PMVECs, disrupts network formation. In contrast, blockade of canonical transient receptor potential (TRP) isoform 4 or TRP vanilloid 4, two other Ca2+ permeable channels expressed in PMVECs, has no effect on network formation. T-type Ca2+ channel blockade also reduces proliferation, cell-matrix adhesion, and migration, three major components of angiogenesis in PMVECs. An in vivo study demonstrated that the mice lacking α1G exhibited a profoundly impaired postinjury cell proliferation in the lungs following lipopolysaccharide challenge. Mechanistically, T-type Ca2+ channel blockade reduces Akt phosphorylation in a dose-dependent manner. Blockade of Akt or its upstream activator, phosphatidylinositol-3-kinase (PI3K), also impairs network formation. Altogether, these findings suggest a novel functional role for the α1G T-type Ca2+ channel to promote the cell's angiogenic potential via a PI3K-Akt signaling pathway.
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Affiliation(s)
- Zhen Zheng
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Hairu Chen
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Peilin Xie
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Carol A Dickerson
- Department of Anesthesiology and Perioperative Medicine, Medical College of Georgia, Augusta University , Augusta, Georgia
| | - Judy A C King
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center , Shreveport, Louisiana
| | - Mikhail F Alexeyev
- Center for Lung Biology and Department of Physiology and Cell Biology, University of South Alabama , Mobile, Alabama
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham , Birmingham, Alabama
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5
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Lambert M, Capuano V, Olschewski A, Sabourin J, Nagaraj C, Girerd B, Weatherald J, Humbert M, Antigny F. Ion Channels in Pulmonary Hypertension: A Therapeutic Interest? Int J Mol Sci 2018; 19:ijms19103162. [PMID: 30322215 PMCID: PMC6214085 DOI: 10.3390/ijms19103162] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a multifactorial and severe disease without curative therapies. PAH pathobiology involves altered pulmonary arterial tone, endothelial dysfunction, distal pulmonary vessel remodeling, and inflammation, which could all depend on ion channel activities (K⁺, Ca2+, Na⁺ and Cl-). This review focuses on ion channels in the pulmonary vasculature and discusses their pathophysiological contribution to PAH as well as their therapeutic potential in PAH.
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Affiliation(s)
- Mélanie Lambert
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
| | - Véronique Capuano
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
| | - Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Stiftingtalstrasse 24, Graz 8010, Austria.
- Department of Physiology, Medical University Graz, Neue Stiftingtalstraße 6, Graz 8010, Austria.
| | - Jessica Sabourin
- Signalisation et Physiopathologie Cardiovasculaire, UMRS 1180, Univ. Paris-Sud, INSERM, Université Paris-Saclay, 92296 Châtenay-Malabry, France.
| | - Chandran Nagaraj
- Ludwig Boltzmann Institute for Lung Vascular Research, Stiftingtalstrasse 24, Graz 8010, Austria.
| | - Barbara Girerd
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
| | - Jason Weatherald
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
- Division of Respirology, Department of Medicine, University of Calgary, Calgary, AB T1Y 6J4, Canada.
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB T1Y 6J4, Canada.
| | - Marc Humbert
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
| | - Fabrice Antigny
- Univ. Paris-Sud, Faculté de Médecine, 94270 Kremlin-Bicêtre, France.
- AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, 94270 Le Kremlin-Bicêtre, France.
- UMRS 999, INSERM and Univ. Paris⁻Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, 92350 Le Plessis Robinson, France.
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Gilbert G, Courtois A, Dubois M, Cussac LA, Ducret T, Lory P, Marthan R, Savineau JP, Quignard JF. T-type voltage gated calcium channels are involved in endothelium-dependent relaxation of mice pulmonary artery. Biochem Pharmacol 2017; 138:61-72. [PMID: 28438566 DOI: 10.1016/j.bcp.2017.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
Abstract
In pulmonary arterial endothelial cells, Ca2+ channels and intracellular Ca2+ concentration ([Ca2+]i) control the release of vasorelaxant factors such as nitric oxide and are involved in the regulation of pulmonary arterial blood pressure. The present study was undertaken to investigate the implication of T-type voltage-gated Ca2+ channels (T-VGCCs, Cav3.1 channel) in the endothelium-dependent relaxation of intrapulmonary arteries. Relaxation was quantified by means of a myograph in wild type and Cav3.1-/- mice. Endothelial [Ca2+]i and NO production were measured, on whole vessels, with the fluo-4 and DAF-fm probes. Acetylcholine (ACh) induced a nitric oxide- and endothelium-dependent relaxation that was significantly reduced in pulmonary arteries from Cav3.1-/- compared to wild type mice as well as in the presence of T-VGCC inhibitors (NNC 55-0396 or mibefradil). ACh also increased endothelial [Ca2+]i and NO production that were both reduced in Cav3.1-/- compared to wild type mice or in the presence of T-VGCC inhibitors. Immunofluorescence labeling revealed the presence of Cav3.1 channels in endothelial cells that co-localized with endothelial nitric oxide synthase in arteries from wild type mice. TRPV4-, beta2 adrenergic- and nitric oxide donors (SNP)-mediated relaxation were not altered in Cav3.1-/- compared to wild type mice. Finally, in chronically hypoxic mice, a model of pulmonary hypertension, ACh relaxation was reduced but still depended on Cav3.1 channels activity. The present study thus demonstrates that T-VGCCs, mainly Cav3.1 channel, contribute to intrapulmonary vascular reactivity in mice by controlling endothelial [Ca2+]i and ACh-mediated relaxation.
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Affiliation(s)
- Guillaume Gilbert
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Arnaud Courtois
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Mathilde Dubois
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Laure-Anne Cussac
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Thomas Ducret
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Philippe Lory
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; Inserm U1191, Montpellier F-34094, France; Université de Montpellier, Montpellier F-34094, France; LabEx 'Ion Channel Science and Therapeutics', Montpellier F-34094, France
| | - Roger Marthan
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France; CHU de Bordeaux, Bordeaux F-33000, France
| | - Jean-Pierre Savineau
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France
| | - Jean-François Quignard
- Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux F-33000, France; Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux F-33000, France.
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7
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Hansen PBL. Functional importance of T-type voltage-gated calcium channels in the cardiovascular and renal system: news from the world of knockout mice. Am J Physiol Regul Integr Comp Physiol 2015; 308:R227-37. [DOI: 10.1152/ajpregu.00276.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Over the years, it has been discussed whether T-type calcium channels Cav3 play a role in the cardiovascular and renal system. T-type channels have been reported to play an important role in renal hemodynamics, contractility of resistance vessels, and pacemaker activity in the heart. However, the lack of highly specific blockers cast doubt on the conclusions. As new T-type channel antagonists are being designed, the roles of T-type channels in cardiovascular and renal pathology need to be elucidated before T-type blockers can be clinically useful. Two types of T-type channels, Cav3.1 and Cav3.2, are expressed in blood vessels, the kidney, and the heart. Studies with gene-deficient mice have provided a way to investigate the Cav3.1 and Cav3.2 channels and their role in the cardiovascular system. This review discusses the results from these knockout mice. Evaluation of the literature leads to the conclusion that Cav3.1 and Cav3.2 channels have important, but different, functions in mice. T-type Cav3.1 channels affect heart rate, whereas Cav3.2 channels are involved in cardiac hypertrophy. In the vascular system, Cav3.2 activation leads to dilation of blood vessels, whereas Cav3.1 channels are mainly suggested to affect constriction. The Cav3.1 channel is also involved in neointima formation following vascular damage. In the kidney, Cav3.1 regulates plasma flow and Cav3.2 plays a role setting glomerular filtration rate. In conclusion, Cav3.1 and Cav3.2 are new therapeutic targets in several cardiovascular pathologies, but the use of T-type blockers should be specifically directed to the disease and to the channel subtype.
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Affiliation(s)
- Pernille B. L. Hansen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
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8
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Sellak H, Zhou C, Liu B, Chen H, Lincoln TM, Wu S. Transcriptional regulation of α1H T-type calcium channel under hypoxia. Am J Physiol Cell Physiol 2014; 307:C648-56. [PMID: 25099734 DOI: 10.1152/ajpcell.00210.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The low-voltage-activated T-type Ca(2+) channels play an important role in mediating the cellular responses to altered oxygen tension. Among three T-type channel isoforms, α1G, α1H, and α1I, only α1H was found to be upregulated under hypoxia. However, mechanisms underlying such hypoxia-dependent isoform-specific gene regulation remain incompletely understood. We, therefore, studied the hypoxia-dependent transcriptional regulation of α1G and α1H gene promoters with the aim to identify the functional hypoxia-response elements (HREs). In rat pulmonary artery smooth muscle cells (PASMCs) and pheochromocytoma (PC12) cells after hypoxia (3% O2) exposure, we observed a prominent increase in α1H mRNA at 12 h along with a significant rise in α1H-mediated T-type current at 24 and 48 h. We then cloned two promoter fragments from the 5'-flanking regions of rat α1G and α1H gene, 2,000 and 3,076 bp, respectively, and inserted these fragments into a luciferase reporter vector. Transient transfection of PASMCs and PC12 cells with these recombinant constructs and subsequent luciferase assay revealed a significant increase in luciferase activity from the reporter containing the α1H, but not α1G, promoter fragment under hypoxia. Using serial deletion and point mutation analysis strategies, we identified a functional HRE at site -1,173cacgc-1,169 within the α1H promoter region. Furthermore, an electrophoretic mobility shift assay using this site as a DNA probe demonstrated an increased binding activity to nuclear protein extracts from the cells after hypoxia exposure. Taken together, these findings indicate that hypoxia-induced α1H upregulation involves binding of hypoxia-inducible factor to an HRE within the α1H promoter region.
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Affiliation(s)
- Hassan Sellak
- Department of Anesthesiology and Perioperative Medicine, Georgia Regents University, Augusta, Georgia
| | - Chun Zhou
- Center for Lung Biology, University of South Alabama, Mobile, Alabama; Department of Pharmacology, University of South Alabama, Mobile, Alabama; and
| | - Bainan Liu
- Center for Lung Biology, University of South Alabama, Mobile, Alabama; Department of Pharmacology, University of South Alabama, Mobile, Alabama; and
| | - Hairu Chen
- Department of Anesthesiology and Perioperative Medicine, Georgia Regents University, Augusta, Georgia
| | - Thomas M Lincoln
- Department of Physiology, University of South Alabama, Mobile, Alabama
| | - Songwei Wu
- Department of Anesthesiology and Perioperative Medicine, Georgia Regents University, Augusta, Georgia;
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Billaud M, Lohman AW, Johnstone SR, Biwer LA, Mutchler S, Isakson BE. Regulation of cellular communication by signaling microdomains in the blood vessel wall. Pharmacol Rev 2014; 66:513-69. [PMID: 24671377 DOI: 10.1124/pr.112.007351] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.
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Affiliation(s)
- Marie Billaud
- Dept. of Molecular Physiology and Biophysics, University of Virginia School of Medicine, PO Box 801394, Charlottesville, VA 22902.
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Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
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Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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Creighton J, Jian M, Sayner S, Alexeyev M, Insel PA. Adenosine monophosphate-activated kinase alpha1 promotes endothelial barrier repair. FASEB J 2011; 25:3356-65. [PMID: 21680893 DOI: 10.1096/fj.10-179218] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The vascular endothelium responds to damage through activation of multiple signaling events that restore cell-cell adhesion and vascular integrity. However, the molecular mechanisms that integrate these events are not clearly defined. Herein, we identify a previously unexpected role for adenosine monophosphate-activated protein kinase (AMPK) in pulmonary microvascular endothelial cell (PMVEC) repair. PMVECs selectively express the AMPKα1 catalytic subunit, pharmacological and short hairpin RNA-mediated inhibition of which attenuates Ca(2+) entry in these cells induced by the inflammatory Ca(2+)-signaling mimetic thapsigargin. We find that AMPKα1 activity is required for the formation of PMVEC cell-cell networks in a prorepair environment and for monolayer resealing after wounding. Decreasing AMPKα1 expression reduces barrier resistance in PMVEC monolayers, results consistent with a role for AMPKα1 in cell-cell adhesion. AMPKα1 colocalizes and coimmunoprecipitates with the adherens junction protein N-cadherin and cofractionates with proteins selectively expressed in caveolar membranes. Assessment of permeability, by measuring the filtration coefficient (K(f)) in isolated perfused lungs, confirmed that AMPK activation contributes to barrier repair in vivo. Our findings thus provide novel evidence for AMPKα1 in Ca(2+) influx-mediated signaling and wound repair in the endothelium.
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Affiliation(s)
- Judy Creighton
- Department of Anesthesiology, University of Alabama, Birmingham, Alabama, USA
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Paffett ML, Riddle MA, Kanagy NL, Resta TC, Walker BR. Altered protein kinase C regulation of pulmonary endothelial store- and receptor-operated Ca2+ entry after chronic hypoxia. J Pharmacol Exp Ther 2010; 334:753-60. [PMID: 20576798 DOI: 10.1124/jpet.110.165563] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic hypoxia (CH)-induced pulmonary hypertension is associated with decreased basal pulmonary artery endothelial cell (EC) Ca(2+), which correlates with reduced store-operated Ca(2+) (SOC) entry. Protein kinase C (PKC) attenuates SOC entry in ECs. Therefore, we hypothesized that PKC has a greater inhibitory effect on EC SOC and receptor-operated Ca(2+) entry after CH. To test this hypothesis, we assessed SOC in the presence or absence of the nonselective PKC inhibitor GF109203X [2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)maleimide] in freshly isolated, Fura-2-loaded ECs obtained from intrapulmonary arteries of control and CH rats (4 weeks at 0.5 atm). We found that SOC entry and 1-oleoyl-2-acetyl-sn-glycerol (OAG)- and ATP-induced Ca(2+) influx were attenuated in ECs from CH rats versus controls, and GF109203X restored SOC and OAG responses to the level of controls. In contrast, nonselective PKC inhibition with GF109203X or the selective PKC(epsilon) inhibitor myristoylated V1-2 attenuated ATP-induced Ca(2+) entry in ECs from control but not CH pulmonary arteries. ATP-induced Ca(2+) entry was also attenuated by the T-type voltage-gated Ca(2+) channel (VGCC) inhibitor mibefradil in control cells. Consistent with the presence of endothelial T-type VGCC, we observed depolarization-induced Ca(2+) influx in control cells that was inhibited by mibefradil. This response was largely absent in ECs from CH arteries. We conclude that CH enhances PKC-dependent inhibition of SOC- and OAG-induced Ca(2+) entry. Furthermore, these data suggest that CH may reduce the ATP-dependent Ca(2+) entry that is mediated, in part, by PKCepsilon and mibefradil-sensitive Ca(2+) channels in control cells.
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Affiliation(s)
- Michael L Paffett
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
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Ochoa CD, Wu S, Stevens T. New developments in lung endothelial heterogeneity: Von Willebrand factor, P-selectin, and the Weibel-Palade body. Semin Thromb Hemost 2010; 36:301-8. [PMID: 20490980 DOI: 10.1055/s-0030-1253452] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Quiescent pulmonary endothelium establishes an antithrombotic, anti-inflammatory surface that promotes blood flow. However, the endothelium rapidly responds to injury and inflammation by promoting thrombosis and enabling the directed transmigration of inflammatory cells, such as neutrophils, into the alveolar airspace. Although the endothelial cell signals responsible for establishing a prothrombotic surface are distinct from those responsible for recognizing circulating neutrophils, these processes are highly interrelated. Von Willebrand factor (VWF)-stimulated secretion plays an important role in thrombus formation, and P-selectin surface expression plays a key role in neutrophil binding necessary for transmigration. Both VWF and P-selectin are located within Weibel-Palade bodies in pulmonary arteries and arterioles, yet Weibel-Palade bodies are absent in capillaries. Despite the absence of the Weibel-Palade bodies, pulmonary capillaries express both VWF and P-selectin. The physiological and pathophysiological significance of these observations is unclear. In this review, we address some anatomical and physiological features that distinguish pulmonary artery, capillary, and vein endothelium. In addition, we review our current understanding regarding the stimulated secretion of VWF and P-selectin in pulmonary artery and capillary endothelium. This information is considered in the context of vasculitis and pneumonia, two pathophysiological processes to which the stimulated secretion of VWF and P-selectin contribute.
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Affiliation(s)
- Cristhiaan D Ochoa
- Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
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Zhou C, Chen H, King JA, Sellak H, Kuebler WM, Yin J, Townsley MI, Shin HS, Wu S. Alpha1G T-type calcium channel selectively regulates P-selectin surface expression in pulmonary capillary endothelium. Am J Physiol Lung Cell Mol Physiol 2010; 299:L86-97. [PMID: 20435690 DOI: 10.1152/ajplung.00331.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Regulated P-selectin surface expression provides a rapid measure for endothelial transition to a proinflammatory phenotype. In general, P-selectin surface expression results from Weibel-Palade body (WPb) exocytosis. Yet, it is unclear whether pulmonary capillary endothelium possesses WPbs or regulated P-selectin surface expression and, if so, how inflammatory stimuli initiate exocytosis. We used immunohistochemistry, immunofluorescence labeling, ultrastructural assessment, and an isolated perfused lung model to demonstrate that capillary endothelium lacks WPbs but possesses P-selectin. Thrombin stimulated P-selectin surface expression in both extra-alveolar vessel and alveolar capillary endothelium. Only in capillaries was the thrombin-stimulated P-selectin surface expression considerably mitigated by pharmacologic blockade of the T-type channel or genetic knockout of the T-type channel alpha(1G)-subunit. Depolarization of endothelial plasma membrane via high K(+) perfusion capable of eliciting cytosolic Ca(2+) transients also provoked P-selectin surface expression in alveolar capillaries that was abolished by T-type channel blockade or alpha(1G) knockout. Our findings reveal an intracellular WPb-independent P-selectin pool in pulmonary capillary endothelium, where the regulated P-selectin surface expression is triggered by Ca(2+) transients evoked through activation of the alpha(1G) T-type channel.
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Affiliation(s)
- Chun Zhou
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama 36688-0002, USA
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Store-operated calcium entry channels in pulmonary endothelium: the emerging story of TRPCS and Orai1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 661:137-54. [PMID: 20204728 DOI: 10.1007/978-1-60761-500-2_9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cells of diverse origin utilize shifts in cytosolic calcium concentrations as intracellular signals to elicit physiological responses. In endothelium, inflammatory first messengers increase cytosolic calcium as a signal to disrupt cell-cell borders and produce inter-cellular gaps. Calcium influx across the plasma membrane is required to initiate barrier disruption, although the calcium entry mechanism responsible for this effect remains poorly understood. This chapter highlights recent efforts to define the molecular anatomy of the ion channel responsible for triggering endothelial cell gap formation. Resolving the identity and function of this calcium channel will pave the way for new anti-inflammatory therapeutic targets.
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Wu S, Jian MY, Xu YC, Zhou C, Al-Mehdi AB, Liedtke W, Shin HS, Townsley MI. Ca2+ entry via alpha1G and TRPV4 channels differentially regulates surface expression of P-selectin and barrier integrity in pulmonary capillary endothelium. Am J Physiol Lung Cell Mol Physiol 2009; 297:L650-7. [PMID: 19617313 DOI: 10.1152/ajplung.00015.2009] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pulmonary vascular endothelial cells express a variety of ion channels that mediate Ca(2+) influx in response to diverse environmental stimuli. However, it is not clear whether Ca(2+) influx from discrete ion channels is functionally coupled to specific outcomes. Thus we conducted a systematic study in mouse lung to address whether the alpha(1G) T-type Ca(2+) channel and the transient receptor potential channel TRPV4 have discrete functional roles in pulmonary capillary endothelium. We used real-time fluorescence imaging for endothelial cytosolic Ca(2+), immunohistochemistry to probe for surface expression of P-selectin, and the filtration coefficient to specifically measure lung endothelial permeability. We demonstrate that membrane depolarization via exposure of pulmonary vascular endothelium to a high-K(+) perfusate induces Ca(2+) entry into alveolar septal endothelial cells and exclusively leads to the surface expression of P-selectin. In contrast, Ca(2+) entry in septal endothelium evoked by the selective TRPV4 activator 4alpha-phorbol-12,13-didecanoate (4alpha-PDD) specifically increases lung endothelial permeability without effect on P-selectin expression. Pharmacological blockade or knockout of alpha(1G) abolishes depolarization-induced Ca(2+) entry and surface expression of P-selectin but does not prevent 4alpha-PDD-activated Ca(2+) entry and the resultant increase in permeability. Conversely, blockade or knockout of TRPV4 specifically abolishes 4alpha-PDD-activated Ca(2+) entry and the increase in permeability, while not impacting depolarization-induced Ca(2+) entry and surface expression of P-selectin. We conclude that in alveolar septal capillaries Ca(2+) entry through alpha(1G) and TRPV4 channels differentially and specifically regulates the transition of endothelial procoagulant phenotype and barrier integrity, respectively.
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Affiliation(s)
- Songwei Wu
- Center for Lung Biology and Dept. of Pharmacology, Univ. of South Alabama College of Medicine, Mobile, AL 36688-0002, USA
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Colsoul B, Nilius B, Vennekens R. On the putative role of transient receptor potential cation channels in asthma. Clin Exp Allergy 2009; 39:1456-66. [PMID: 19624522 DOI: 10.1111/j.1365-2222.2009.03315.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The mammalian transient receptor potential (TRP) superfamily consists of 28 mammalian TRP cation channels, which can be subdivided into six main subfamilies: the TRPC ('Canonical'), TRPV ('Vanilloid'), TRPM ('Melastatin'), TRPP ('Polycystin'), TRPML ('Mucolipin') and the TRPA ('Ankyrin') groups. Increasing evidence has accumulated during the previous few years that links TRP channels to the cause of several diseases or to critically influence and/or determine their progress. This review focuses on the possible role of TRP channels in the aetiology of asthmatic lung disease.
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Affiliation(s)
- B Colsoul
- Laboratory Ion Channel Research, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
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Jensen LJ, Holstein-Rathlou NH. Is there a role for T-type Ca2+ channels in regulation of vasomotor tone in mesenteric arterioles? Can J Physiol Pharmacol 2009; 87:8-20. [PMID: 19142211 DOI: 10.1139/y08-101] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The largest peripheral blood pressure drop occurs in terminal arterioles (<40 microm lumen diameter). L-type voltage-dependent Ca2+ channels (VDCCs) are considered the primary pathway for Ca2+ influx during physiologic activation of vascular smooth muscle cells (VSMC). Recent evidence suggests that T-type VDCCs are expressed in renal afferent and efferent arterioles, mesenteric arterioles, and skeletal muscle arterioles. T-type channels are small-conductance, low voltage-activated, fast-inactivating channels. Thus, their role in supplying Ca2+ for contraction of VSMC has been disputed. However, T-type channels display non-inactivating window currents, which may play a role in sustained Ca2+ entry. Here, we review the possible role of T-type channels in vasomotor tone regulation in rat mesenteric terminal arterioles. The CaV3.1 channel was immunolocalized in VSMC, whereas the CaV3.2 channel was predominantly expressed in endothelial cells. Voltage-dependent Ca2+ entry was inhibited by the new specific T-type blockers R(-)-efonidipine and NNC 55-0396. The effect of NNC 55-0396 persisted in depolarized arterioles, suggesting an unusually high activation threshold of mesenteric T-type channels. T-type channels were not necessary for conduction of vasoconstriction, but appear to be important for local electromechanical coupling in VSMC. The first direct demonstration of endothelial T-type channels warrants new investigations of their role in vascular biology.
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Affiliation(s)
- Lars Jørn Jensen
- Division of Renal and Vascular Research, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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Moldobaeva A, Jenkins J, Wagner E. Effects of distension on airway inflammation and venular P-selectin expression. Am J Physiol Lung Cell Mol Physiol 2008; 295:L941-8. [PMID: 18805956 DOI: 10.1152/ajplung.90447.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We previously have shown in mice and rats, enhanced leukocyte recruitment to airway postcapillary venules after excessive distention imposed by the application of positive end-expiratory pressure. Because P-selectin was shown to be essential for this outcome, we sought to establish an in vitro endothelial cell model and determine the mechanisms whereby mechanical distension alters adhesion molecule expression. P-selectin surface expression on mouse jugular vein endothelial cells exposed to cyclic stretch (5 or 20% elongation for 5 min; Flexercell) were compared with static cells. The larger, pathophysiological regimen of cyclic stretch showed a 54% increase in P-selectin expression after stretch compared with static cells. This response was attenuated but confirmed in tracheal venular endothelium (29% increase). We questioned whether these changes were dependent on increases in intracellular Ca(2+) through voltage-gated Ca(2+) channels. The stretch-induced increase in P-selectin expression was substantially decreased by pretreatment with the T-type Ca(2+) channel inhibitor mibefradil (76% inhibition). Furthermore, when the Ca(v)3.1 T-type Ca(2+) channel expression was decreased in both endothelial cell subtypes with specific small-interfering RNA, the distension-induced expression of P-selectin decreased to levels less than that observed in static cells. We conclude that P-selectin expression on systemic venular endothelial cells contributes to a proinflammatory phenotype after mechanical stretch and can be selectively modulated by voltage-gated calcium channel inhibition.
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Affiliation(s)
- Aigul Moldobaeva
- Johns Hopkins Asthma and Allergy Center, Division of Pulmonary and Critical Care Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
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De Proost I, Brouns I, Pintelon I, Timmermans JP, Adriaensen D. Pulmonary expression of voltage-gated calcium channels: special reference to sensory airway receptors. Histochem Cell Biol 2007; 128:301-16. [PMID: 17690900 DOI: 10.1007/s00418-007-0318-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2007] [Indexed: 10/23/2022]
Abstract
Studying depolarisation induced calcium entry in our recently developed in situ lung slice model for molecular live cell imaging of selectively visualised pulmonary neuroepithelial bodies (NEBs), exemplified the need for information on the localisation of voltage-gated calcium channels (Ca(v)) in lungs in general, and related to sensory airway receptors more specifically. The present study therefore aimed at identifying the expression pattern of all major classes and subtypes of Ca(v) channels, using multiple immunostaining of rat lung cryosections. Ca(v) channel antibodies were combined with antibodies that selectively label NEBs, nerve fibre populations, smooth muscle, endothelium and Clara cells. Ca(v)2.1 (P/Q-type) was the only Ca(v) channel expressed in NEB cell membranes, and appeared to be restricted to the apical membrane of the slender NEB cell processes that reach the airway lumen. Subpopulations of the vagal but not the spinal sensory nerve fibres that contact NEBs showed immunoreactivity (IR) for Ca(v)1.2 (L-type) and Ca(v)2.1. Ca(v)2.3 (R-type) was selectively expressed by the so-called Clara-like cells that cover NEBs only, and appears to be a unique marker to discriminate this epithelial cell type from the much more extensive group of Clara cells in rat airways. The laminar nerve endings of smooth muscle-associated airway receptors (SMARs) revealed IR for both Ca(v)2.1 and Ca(v)2.2 (N-type). More generally, Ca(v)1.2 was seen to be expressed in vascular smooth muscle, Ca(v)2.3 and Ca(v)3.1 (T-type) in bronchial smooth muscle, Ca(v)3.1 and Ca(v)3.2 (T-type) in endothelial cells, and Ca(v)1.3 (L-type) in a limited number of epithelial cells. In conclusion, the present immunocytochemical study has demonstrated that the various subtypes of Ca(v) channels have distinct expression patterns in rat lungs. Special focus on morphologically/neurochemically characterised sensory airway receptors learned us that both NEBs and SMARs present Ca(v) channels. Knowledge of the identification and localisation of Ca(v) channels in airway receptors and surrounding tissues provides a solid basis for interpretation of the calcium mediated activation studied in our ex vivo lung slice model.
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Affiliation(s)
- Ian De Proost
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Groenenborgerlaan 171, BE-2020, Antwerp, Belgium.
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