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Theerathananon W, Watanapa WB, Wataganara T, Pratumvinit B, Rahman S. Preeclamptic serum and soluble fms-like tyrosine kinase-1 suppress endothelial inward rectifier potassium currents. Placenta 2024; 146:101-109. [PMID: 38241839 DOI: 10.1016/j.placenta.2024.01.002] [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: 08/09/2023] [Revised: 11/01/2023] [Accepted: 01/03/2024] [Indexed: 01/21/2024]
Abstract
INTRODUCTION Inward rectifier K+ (Kir) channel, a major factor determining endothelial membrane potential, regulates Ca2+ influx and vasodilator release, which is impaired in preeclamptic blood vessels. Previously, human umbilical vein endothelial cell (HUVEC) Kir currents were shown to decrease after incubating in preeclamptic plasma. We aimed to demonstrate whether sFlt-1, which is high in preeclamptic blood, could inhibit Kir channel function and expression. METHODS HUVECs were cultured in regular medium, regular medium with added sFlt-1, or serum from preeclampsia patients or normal pregnant women (Control, sFlt-1, PE, or NP, respectively). Using whole-cell patch clamp technique, we identified Kir currents with the Kir blocker 2 mM BaCl2 and compared the currents among groups. The expression of Kir 2.1 and 2.2 channels were determined using immunofluorescent staining. RESULTS sFlt-1 and PE groups exhibited similar Kir currents, while NP group possessed significantly larger currents, similar to Control group currents. Moreover, sFlt-1 and sFlt-1/PlGF ratio showed strong negative correlation with Kir currents (r = -0.71 and -0.70, respectively; P < 0.05). There were no significant differences in mean fluorescence intensity representing Kir 2.1 and 2.2 channels expression in all four groups. DISCUSSION This is the first report to demonstrate sFlt-1 inhibition against Kir currents, which could lead to maternal endothelial dysfunction and hypertension seen in preeclampsia. However, channel expression was unaffected by sFlt-1 incubation, suggesting dysfunctions of channel or other processes (e.g., membrane translocation). The present data could pave the way for novel therapies targeting sFlt-1 or Kir to alleviate hypertension in preeclampsia.
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Affiliation(s)
- Wuttinan Theerathananon
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok, 10700, Thailand.
| | - Wattana B Watanapa
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok, 10700, Thailand.
| | - Tuangsit Wataganara
- Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok, 10700, Thailand.
| | - Busadee Pratumvinit
- Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok, 10700, Thailand.
| | - Suraiya Rahman
- Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkok, 10700, Thailand.
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications. Handb Exp Pharmacol 2021; 267:277-356. [PMID: 34345939 DOI: 10.1007/164_2021_501] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K+ channels. In the present review we focus on placing the physiology and pharmacology of this K+ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.
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Terwoord JD, Racine ML, Hearon CM, Luckasen GJ, Dinenno FA. ATP and acetylcholine interact to modulate vascular tone and α 1-adrenergic vasoconstriction in humans. J Appl Physiol (1985) 2021; 131:566-574. [PMID: 34166116 DOI: 10.1152/japplphysiol.00205.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vascular endothelium senses and integrates numerous inputs to regulate vascular tone. Recent evidence reveals complex signal processing within the endothelium, yet little is known about how endothelium-dependent stimuli interact to regulate blood flow. We tested the hypothesis that combined stimulation of the endothelium with adenosine triphosphate (ATP) and acetylcholine (ACh) elicits greater vasodilation and attenuates α1-adrenergic vasoconstriction compared with combination of ATP or ACh with the endothelium-independent dilator sodium nitroprusside (SNP). We assessed forearm vascular conductance (FVC) in young adults (6 women, 7 men) during local intra-arterial infusion of ATP, ACh, or SNP alone and in the following combinations: ATP + ACh, SNP + ACh, and ATP + SNP, wherein the second dilator was coinfused after attaining steady state with the first dilator. By design, each dilator evoked a similar response when infused separately (ΔFVC, ATP: 48 ± 4; ACh: 57 ± 6; SNP: 53 ± 6 mL·min-1·100 mmHg-1; P ≥ 0.62). Combined infusion of the endothelium-dependent dilators evoked greater vasodilation than combination of either dilator with SNP (ΔFVC from first dilator, ATP + ACh: 45 ± 9 vs. SNP + ACh: 18 ± 7 and ATP + SNP: 26 ± 4 mL·min-1·100 mmHg-1, P < 0.05). Phenylephrine was subsequently infused to evaluate α1-adrenergic vasoconstriction. Phenylephrine elicited less vasoconstriction during infusion of ATP or ACh versus SNP (ΔFVC, -25 ± 3 and -29 ± 4 vs. -48 ± 3%; P < 0.05). The vasoconstrictor response to phenylephrine was further diminished during combined infusion of ATP + ACh (-13 ± 3%; P < 0.05 vs. ATP or ACh alone) and was less than that observed when either dilator was combined with SNP (SNP + ACh: -26 ± 3%; ATP + SNP: -31 ± 4%; both P < 0.05 vs. ATP + ACh). We conclude that endothelium-dependent agonists interact to elicit vasodilation and limit α1-adrenergic vasoconstriction in humans.NEW & NOTEWORTHY The results of this study highlight the vascular endothelium as a critical site for integration of vasomotor signals in humans. To our knowledge, this is the first study to demonstrate that combined stimulation of the endothelium with ATP and ACh results in enhanced vasodilation compared with combination of either ATP or ACh with an endothelium-independent dilator. Furthermore, we show that ATP and ACh interact to modulate α1-adrenergic vasoconstriction in human skeletal muscle in vivo.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, Colorado
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado
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Zhuang F, Bao H, Shi Q, Li J, Jiang Z, Wang Y, Qi Y. Endothelial microparticles induced by cyclic stretch activate Src and modulate cell apoptosis. FASEB J 2020; 34:13586-13596. [DOI: 10.1096/fj.202000581r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/03/2020] [Accepted: 07/27/2020] [Indexed: 02/01/2023]
Affiliation(s)
- Fei Zhuang
- Institute of Mechanobiology & Medical Engineering School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
| | - Han Bao
- Institute of Mechanobiology & Medical Engineering School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
| | - Qian Shi
- Institute of Mechanobiology & Medical Engineering School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
| | - Jing Li
- Department of Bioinformatics and Biostatistics School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
| | - Zong‐Lai Jiang
- Institute of Mechanobiology & Medical Engineering School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
| | - Yingxiao Wang
- Department of Bioengineering University of California San Diego CA USA
| | - Ying‐Xin Qi
- Institute of Mechanobiology & Medical Engineering School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai China
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical Engineering Beihang University Beijing China
- Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing China
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Zhuang F, Shi Q, Wang WB, Bao H, Yan J, Gao S, Liu Z, Jiang ZL, Qi YX. Endothelial microvesicles induced by physiological cyclic stretch inhibit ICAM1-Dependent leukocyte adhesion. Exp Cell Res 2020; 386:111710. [PMID: 31693873 DOI: 10.1016/j.yexcr.2019.111710] [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: 07/07/2019] [Revised: 10/22/2019] [Accepted: 10/31/2019] [Indexed: 01/21/2023]
Abstract
Physiological cyclic stretch (CS), caused by artery deformation following blood pressure, plays important roles in the homeostasis of endothelial cells (ECs). Here, we detected the effect of physiological CS on endothelial microvesicles (EMVs) and their roles in leukocyte recruitment to ECs, which is a crucial event in EC inflammation. The results showed compared with the static treatment, pretreatment of 5%-CS-derived EMVs with ECs significantly decreased the adherence level of leukocytes. Comparative proteomic analysis revealed 373 proteins differentially expressed between static-derived and 5%-CS-derived EMVs, in which 314 proteins were uniquely identified in static-derived EMVs, 34 proteins uniquely in 5%-CS-derived EMVs, and 25 proteins showed obvious differences. Based on the proteomic data, Ingenuity Pathways Analysis predicted intercellular adhesion molecule 1 (ICAM1) in EMVs might be the potential molecule involved in EC-leukocyte adhesion. Western blot and flow cytometry analyses confirmed the significant decrease of ICAM1 in 5%-CS-derived EMVs, which subsequently inhibited the phosphorylation of VE-cadherin at Tyr731 in target ECs. Moreover, leukocyte adhesion was obviously decreased after pretreatment with ICAM1 neutralizing antibody. Our present research suggested that physiological stretch changes the components of EMVs, which in turn inhibits leukocyte adhesion. ICAM1 expressed on CS-induced EMVs may play an important role in maintaining EC homeostasis.
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Affiliation(s)
- Fei Zhuang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qian Shi
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wen-Bin Wang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Han Bao
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Yan
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Shuang Gao
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ze Liu
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zong-Lai Jiang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ying-Xin Qi
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences &Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China; Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100083, China.
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Li G, Yang Q, Yang Y, Yang G, Wan J, Ma Z, Du L, Sun Y, Ζhang G. Laminar shear stress alters endothelial KCa2.3 expression in H9c2 cells partially via regulating the PI3K/Akt/p300 axis. Int J Mol Med 2019; 43:1289-1298. [PMID: 30664154 PMCID: PMC6365081 DOI: 10.3892/ijmm.2019.4063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022] Open
Abstract
In cardiac tissues, myoblast atrial myocytes continue to be exposed to mechanical forces including shear stress. However, little is known about the effects of shear stress on atrial myocytes, particularly on ion channel function, in association with disease. The present study demonstrated that the Ca2+-activated K+ channel (KCa)2.3 serves a vital role in regulating arterial tone. As increased intracellular Ca2+ levels and activation of histone acetyltransferase p300 (p300) are early responses to laminar shear stress (LSS) that result in the transcriptional activation of genes, the role of p300 and the phosphoinositide3-kinase (PI3K)/protein kinase B (Akt) pathway, an intracellular pathway that promotes the growth and proliferation rather than the differentiation of adult cells, in the LSS-dependent regulation of KCa2.3 in cardiac myoblasts was examined. In cultured H9c2 cells, exposure to LSS (15 dyn/cm2) for 12 h markedly increased KCa2.3 mRNA expression. Inhibiting PI3K attenuated the LSS-induced increases in the expression and channel activity of KCa2.3, and decreased the phosphorylation levels of p300. The upregulation of these channels was abolished by the inhibition of Akt through decreasing p300 phosphorylation. ChIP assays indicated that p300 was recruited to the promoter region of the KCa2.3 gene. Therefore, the PI3K/Akt/p300 axis serves a crucial role in the LSS-dependent induction of KCa2.3 expression, by regulating cardiac myoblast function and adaptation to hemodynamic changes. The key novel insights gained from the present study are: i) KCa2.3 was upregulated in patients with atrial fibrillation (AF) and in patients with AF combined with mitral value disease; ii) LSS induced a profound upregulation of KCa2.3 mRNA and protein expression in H9c2 cells; iii) PI3K activation was associated with LSS-induced upregulation of the KCa2.3 channel; iv) PI3K activation was mediated by PI3K/Akt-dependent Akt activation; and v) LSS induction of KCa2.3 involved the binding of p300 to transcription factors in the promoter region of the KCa2.3 gene.
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Affiliation(s)
- Guojian Li
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Qionghui Yang
- Department of Pharmacy, The Third People's Hospital of Yunnan Province, Kunming, Yunnan 650200, P.R. China
| | - Yong Yang
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Guokai Yang
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Jia Wan
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Zhenhuan Ma
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Lingjuan Du
- Department of Vascular Surgery, The Second People's Hospital of Yunnan Province, Kunming Medical University, Kunming, Yunnan 650200, P.R. China
| | - Yi Sun
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650021, P.R. China
| | - Guimin Ζhang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650021, P.R. China
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Hearon CM, Richards JC, Racine ML, Luckasen GJ, Larson DG, Dinenno FA. Amplification of endothelium-dependent vasodilatation in contracting human skeletal muscle: role of K IR channels. J Physiol 2018; 597:1321-1335. [PMID: 30506579 DOI: 10.1113/jp276998] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/29/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS In humans, the vasodilatory response to skeletal muscle contraction is mediated in part by activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels serve as electrical amplifiers of endothelium-dependent hyperpolarization (EDH). We found that skeletal muscle contraction amplifies vasodilatation to the endothelium-dependent agonist ACh, whereas there was no change in the vasodilatory response to sodium nitroprusside, an endothelium-independent nitric oxide donor. Blockade of KIR channels reduced the exercise-induced amplification of ACh-mediated vasodilatation. Conversely, pharmacological activation of KIR channels in quiescent muscle via intra-arterial infusion of KCl independently amplified the vasodilatory response to ACh. This study is the first in humans to demonstrate that specific endothelium-dependent vasodilatory signalling is amplified in the vasculature of contracting skeletal muscle and that KIR channels may serve as amplifiers of EDH-like vasodilatory signalling in humans. ABSTRACT The local vasodilatory response to muscle contraction is due in part to the activation of inwardly rectifying potassium (KIR ) channels. Evidence from animal models suggest that KIR channels function as 'amplifiers' of endothelium-dependent vasodilators. We tested the hypothesis that contracting muscle selectively amplifies endothelium-dependent vasodilatation via activation of KIR channels. We measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (FVC) to local intra-arterial infusion of ACh (endothelium-dependent dilator) during resting conditions, handgrip exercise (5% maximum voluntary contraction) or sodium nitroprusside (SNP; endothelium-independent dilator) which served as a high-flow control condition (n = 7, young healthy men and women). Trials were performed before and after blockade of KIR channels via infusion of barium chloride. Exercise augmented peak ACh-mediated vasodilatation (ΔFVC saline: 117 ± 14; exercise: 236 ± 21 ml min-1 (100 mmHg)-1 ; P < 0.05), whereas SNP did not impact ACh-mediated vasodilatation. Blockade of KIR channels attenuated the exercise-induced augmentation of ACh. In eight additional subjects, SNP was administered as the experimental dilator. In contrast to ACh, exercise did not alter SNP-mediated vasodilatation (ΔFVC saline: 158 ± 35; exercise: 121 ± 22 ml min-1 (100 mmHg)-1 ; n.s.). Finally, in a subset of six subjects, direct pharmacological activation of KIR channels in quiescent muscle via infusion of KCl amplified peak ACh-mediated vasodilatation (ΔFVC saline: 97 ± 15, KCl: 142 ± 16 ml min-1 (100 mmHg)-1 ; respectively; P < 0.05). These findings indicate that skeletal muscle contractions selectively amplify endothelium-dependent vasodilatory signalling via activation of KIR channels, and this may be an important mechanism contributing to the normal vasodilatory response to exercise in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Mathew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Dennis G Larson
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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Alevriadou BR, Shanmughapriya S, Patel A, Stathopulos PB, Madesh M. Mitochondrial Ca 2+ transport in the endothelium: regulation by ions, redox signalling and mechanical forces. J R Soc Interface 2017; 14:rsif.2017.0672. [PMID: 29237825 DOI: 10.1098/rsif.2017.0672] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/16/2017] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca2+) transport by mitochondria is an important component of the cell Ca2+ homeostasis machinery in metazoans. Ca2+ uptake by mitochondria is a major determinant of bioenergetics and cell fate. Mitochondrial Ca2+ uptake occurs via the mitochondrial Ca2+ uniporter (MCU) complex, an inner mitochondrial membrane protein assembly consisting of the MCU Ca2+ channel, as its core component, and the MCU complex regulatory/auxiliary proteins. In this review, we summarize the current knowledge on the molecular nature of the MCU complex and its regulation by intra- and extramitochondrial levels of divalent ions and reactive oxygen species (ROS). Intracellular Ca2+ concentration ([Ca2+]i), mitochondrial Ca2+ concentration ([Ca2+]m) and mitochondrial ROS (mROS) are intricately coupled in regulating MCU activity. Here, we highlight the contribution of MCU activity to vascular endothelial cell (EC) function. Besides the ionic and oxidant regulation, ECs are continuously exposed to haemodynamic forces (either pulsatile or oscillatory fluid mechanical shear stresses, depending on the precise EC location within the arteries). Thus, we also propose an EC mechanotransduction-mediated regulation of MCU activity in the context of vascular physiology and atherosclerotic vascular disease.
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Affiliation(s)
- B Rita Alevriadou
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA .,Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA.,Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry, Temple University, Philadelphia, PA 19140, USA.,Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Akshar Patel
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.,Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA.,Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada N6A 5C1
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry, Temple University, Philadelphia, PA 19140, USA .,Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
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Wang Y, Jin L. miRNA-145 is associated with spontaneous hypertension by targeting SLC7A1. Exp Ther Med 2017; 15:548-552. [PMID: 29434681 DOI: 10.3892/etm.2017.5371] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/16/2017] [Indexed: 12/15/2022] Open
Abstract
Previous studies have indicated that microRNAs (miRNAs/miRs) may participate in the pathogenesis of hypertension. miR-145 has been demonstrated to serve important roles in the development of numerous cardiovascular diseases. However, the specific role of miR-145 in hypertension remains unclear. The present study aimed to investigate the role of miR-145 in spontaneously hypertensive rats (SHR) and rat vascular endothelial cells (RVECs). The results of the present study demonstrated that in the SHR group miR-145 expression was significantly upregulated in the thoracic aorta compared with the control group. Furthermore, a significant decrease in nitric oxide (NO) content was observed in the SHR group compared with the control rats. In RVECs, silencing miR-145 induced a significant increase in the expression of solute carrier family 7 member 1 (SLC7A1) and phosphorylated endothelial nitric oxide synthase, and a dual-luciferase reporter assay confirmed that SLC7A1 is a direct target of miR-145. The results of the present study indicate that miR-145 functions as a key mediator in the pathogenesis of hypertension via targeting SLC7A1, which suggests that miR-145 is a potential target for the treatment of hypertension.
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Affiliation(s)
- Yong Wang
- Department of General Practice, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, P.R. China
| | - Liyan Jin
- Department of Cardiology, The Second Affiliated Hospital of Henan College of Traditional Chinese Medicine, Zhengzhou, Henan 450002, P.R. China
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Dual contribution of TRPV4 antagonism in the regulatory effect of vasoinhibins on blood-retinal barrier permeability: diabetic milieu makes a difference. Sci Rep 2017; 7:13094. [PMID: 29026201 PMCID: PMC5638810 DOI: 10.1038/s41598-017-13621-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/29/2017] [Indexed: 01/05/2023] Open
Abstract
Breakdown of the blood-retinal barrier (BRB), as occurs in diabetic retinopathy and other chronic retinal diseases, results in vasogenic edema and neural tissue damage, causing vision loss. Vasoinhibins are N-terminal fragments of prolactin that prevent BRB breakdown during diabetes. They modulate the expression of some transient receptor potential (TRP) family members, yet their role in regulating the TRP vanilloid subtype 4 (TRPV4) remains unknown. TRPV4 is a calcium-permeable channel involved in barrier permeability, which blockade has been shown to prevent and resolve pulmonary edema. We found TRPV4 expression in the endothelium and retinal pigment epithelium (RPE) components of the BRB, and that TRPV4-selective antagonists (RN-1734 and GSK2193874) resolve BRB breakdown in diabetic rats. Using human RPE (ARPE-19) cell monolayers and endothelial cell systems, we further observed that (i) GSK2193874 does not seem to contribute to the regulation of BRB and RPE permeability by vasoinhibins under diabetic or hyperglycemic-mimicking conditions, but that (ii) vasoinhibins can block TRPV4 to maintain BRB and endothelial permeability. Our results provide important insights into the pathogenesis of diabetic retinopathy that will further guide us toward rationally-guided new therapies: synergistic combination of selective TRPV4 blockers and vasoinhibins can be proposed to mitigate diabetes-evoked BRB breakdown.
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Secreted miR-27a Induced by Cyclic Stretch Modulates the Proliferation of Endothelial Cells in Hypertension via GRK6. Sci Rep 2017; 7:41058. [PMID: 28106155 PMCID: PMC5247685 DOI: 10.1038/srep41058] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 12/15/2016] [Indexed: 11/08/2022] Open
Abstract
Abnormal proliferation of endothelial cells (ECs) is important in vascular remodeling during hypertension, but the mechanisms are still unclear. In hypertensive rats caused by abdominal aortic coarctation, the expression of G-protein-coupled receptor kinase 6 (GRK6) in ECs at common carotid artery was repressed in vivo, and EC proliferation was increased. 15% cyclic stretch in vitro, which mimics the pathologically increased stretch in hypertension, repressed EC GRK6 expression via paracrine control by vascular smooth muscle cells (VSMCs). Furthermore, VSMC-derived microparticles (VSMC-MPs) were detected in the conditioned medium from VSMCs and in artery. VSMC-MPs from cells exposed to 15% cyclic stretch decreased GRK6 expression and increased EC proliferation. miR-27a was detected in VSMC-MPs and was upregulated by 15% cyclic stretch. miR-27a was transferred from VSMCs to ECs via VSMC-MPs and directly targeted on GRK6. Finally, a multi-point injection of antagomiR-27a around carotid artery decreased miR-27a expression in vivo, induced GRK6 expression, and reversed the abnormal EC proliferation. Pathologically elevated cyclic stretch increased the secretion of miR-27a, which was transferred from VSMCs to ECs via the VSMC-MPs, subsequently targeted GRK6, and induced EC proliferation. Locally decreasing miR-27a could be a novel therapeutic approach to attenuate the abnormal EC proliferation in hypertension.
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Fluid flow facilitates inward rectifier K + current by convectively restoring [K +] at the cell membrane surface. Sci Rep 2016; 6:39585. [PMID: 28004830 PMCID: PMC5177964 DOI: 10.1038/srep39585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 11/24/2016] [Indexed: 01/25/2023] Open
Abstract
The inward rectifier Kir2.1 current (IKir2.1) was reported to be facilitated by fluid flow. However, the mechanism underlying this facilitation remains uncertain. We hypothesized that during K+ influx or efflux, [K+] adjacent to the outer mouth of the Kir2.1 channel might decrease or increase, respectively, compared with the average [K+] of the bulk extracellular solution, and that fluid flow could restore the original [K+] and result in the apparent facilitation of IKir2.1. We recorded the IKir2.1 in RBL-2H3 cells and HEK293T cells that were ectopically over-expressed with Kir2.1 channels by using the whole-cell patch-clamp technique. Fluid-flow application immediately increased the IKir2.1, which was not prevented by either the pretreatment with inhibitors of various protein kinases or the modulation of the cytoskeleton and caveolae. The magnitudes of the increases of IKir2.1 by fluid flow were driving force-dependent. Simulations performed using the Nernst-Planck mass equation indicated that [K+] near the membrane surface fell markedly below the average [K+] of the bulk extracellular solution during K+ influx, and, notably, that fluid flow restored the decreased [K+] at the cell surface in a flow rate-dependent manner. These results support the “convection-regulation hypothesis” and define a novel interpretation of fluid flow-induced modulation of ion channels.
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Abstract
Fluid shear stress is an important environmental cue that governs vascular physiology and pathology, but the molecular mechanisms that mediate endothelial responses to flow are only partially understood. Gating of ion channels by flow is one mechanism that may underlie many of the known responses. Here, we review the literature on endothelial ion channels whose activity is modulated by flow with an eye toward identifying important questions for future research.
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Affiliation(s)
- Kristin A Gerhold
- Department of Internal Medicine (Cardiology), Yale Cardiovascular Research Center, Yale University, New Haven, Connecticut; and
| | - Martin A Schwartz
- Department of Internal Medicine (Cardiology), Yale Cardiovascular Research Center, Yale University, New Haven, Connecticut; and Departments of Cell Biology and Biomedical Engineering, Yale University, New Haven, Connecticut
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15
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Scheitlin CG, Julian JA, Shanmughapriya S, Madesh M, Tsoukias NM, Alevriadou BR. Endothelial mitochondria regulate the intracellular Ca2+ response to fluid shear stress. Am J Physiol Cell Physiol 2016; 310:C479-90. [PMID: 26739489 DOI: 10.1152/ajpcell.00171.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/04/2016] [Indexed: 02/04/2023]
Abstract
Shear stress is known to stimulate an intracellular free calcium concentration ([Ca(2+)]i) response in vascular endothelial cells (ECs). [Ca(2+)]i is a key second messenger for signaling that leads to vasodilation and EC survival. Although it is accepted that the shear-induced [Ca(2+)]i response is, in part, due to Ca(2+) release from the endoplasmic reticulum (ER), the role of mitochondria (second largest Ca(2+) store) is unknown. We hypothesized that the mitochondria play a role in regulating [Ca(2+)]i in sheared ECs. Cultured ECs, loaded with a Ca(2+)-sensitive fluorophore, were exposed to physiological levels of shear stress. Shear stress elicited [Ca(2+)]i transients in a percentage of cells with a fraction of them displaying oscillations. Peak magnitudes, percentage of oscillating ECs, and oscillation frequencies depended on the shear level. [Ca(2+)]i transients/oscillations were present when experiments were conducted in Ca(2+)-free solution (plus lanthanum) but absent when ECs were treated with a phospholipase C inhibitor, suggesting that the ER inositol 1,4,5-trisphosphate receptor is responsible for the [Ca(2+)]i response. Either a mitochondrial uncoupler or an electron transport chain inhibitor, but not a mitochondrial ATP synthase inhibitor, prevented the occurrence of transients and especially inhibited the oscillations. Knockdown of the mitochondrial Ca(2+) uniporter also inhibited the shear-induced [Ca(2+)]i transients/oscillations compared with controls. Hence, EC mitochondria, through Ca(2+) uptake/release, regulate the temporal profile of shear-induced ER Ca(2+) release. [Ca(2+)]i oscillation frequencies detected were within the range for activation of mechanoresponsive kinases and transcription factors, suggesting that dysfunctional EC mitochondria may contribute to cardiovascular disease by deregulating the shear-induced [Ca(2+)]i response.
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Affiliation(s)
- Christopher G Scheitlin
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Justin A Julian
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry and Center for Translational Medicine, Temple University, Philadelphia, Pennsylvania; and
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - B Rita Alevriadou
- Departments of Biomedical Engineering and Internal Medicine, Division of Cardiovascular Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio;
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16
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Hill-Eubanks DC, Gonzales AL, Sonkusare SK, Nelson MT. Vascular TRP channels: performing under pressure and going with the flow. Physiology (Bethesda) 2015; 29:343-60. [PMID: 25180264 DOI: 10.1152/physiol.00009.2014] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelial cells and smooth muscle cells of resistance arteries mediate opposing responses to mechanical forces acting on the vasculature, promoting dilation in response to flow and constriction in response to pressure, respectively. In this review, we explore the role of TRP channels, particularly endothelial TRPV4 and smooth muscle TRPC6 and TRPM4 channels, in vascular mechanosensing circuits, placing their putative mechanosensitivity in context with other proposed upstream and downstream signaling pathways.
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Affiliation(s)
| | - Albert L Gonzales
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | | | - Mark T Nelson
- Department of Pharmacology, University of Vermont, Burlington, Vermont
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17
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Han Y, Wang L, Yao QP, Zhang P, Liu B, Wang GL, Shen BR, Cheng B, Wang Y, Jiang ZL, Qi YX. Nuclear envelope proteins Nesprin2 and LaminA regulate proliferation and apoptosis of vascular endothelial cells in response to shear stress. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1165-73. [PMID: 25721888 DOI: 10.1016/j.bbamcr.2015.02.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/19/2015] [Accepted: 02/15/2015] [Indexed: 11/27/2022]
Abstract
The dysfunction of vascular endothelial cells (ECs) influenced by flow shear stress is crucial for vascular remodeling. However, the roles of nuclear envelope (NE) proteins in shear stress-induced EC dysfunction are still unknown. Our results indicated that, compared with normal shear stress (NSS), low shear stress (LowSS) suppressed the expression of two types of NE proteins, Nesprin2 and LaminA, and increased the proliferation and apoptosis of ECs. Targeted small interfering RNA (siRNA) and gene overexpression plasmid transfection revealed that Nesprin2 and LaminA participate in the regulation of EC proliferation and apoptosis. A protein/DNA array was further used to detect the activation of transcription factors in ECs following transfection with target siRNAs and overexpression plasmids. The regulation of AP-2 and TFIID mediated by Nesprin2 and the activation of Stat-1, Stat-3, Stat-5 and Stat-6 by LaminA were verified under shear stress. Furthermore, using Ingenuity Pathway Analysis software and real-time RT-PCR, the effects of Nesprin2 or LaminA on the downstream target genes of AP-2, TFIID, and Stat-1, Stat-3, Stat-5 and Stat-6, respectively, were investigated under LowSS. Our study has revealed that NE proteins are novel mechano-sensitive molecules in ECs. LowSS suppresses the expression of Nesprin2 and LaminA, which may subsequently modulate the activation of important transcription factors and eventually lead to EC dysfunction.
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Affiliation(s)
- Yue Han
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lu Wang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qing-Ping Yao
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ping Zhang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Bo Liu
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Liang Wang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Bao-Rong Shen
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Binbin Cheng
- Department of Bioengineering, University of CA, San Diego, USA
| | - Yingxiao Wang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Department of Bioengineering, University of CA, San Diego, USA
| | - Zong-Lai Jiang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ying-Xin Qi
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
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18
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Du J, Ma X, Shen B, Huang Y, Birnbaumer L, Yao X. TRPV4, TRPC1, and TRPP2 assemble to form a flow-sensitive heteromeric channel. FASEB J 2014; 28:4677-85. [PMID: 25114176 DOI: 10.1096/fj.14-251652] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Transient receptor potential (TRP) channels, a superfamily of ion channels, can be divided into 7 subfamilies, including TRPV, TRPC, TRPP, and 4 others. Functional TRP channels are tetrameric complexes consisting of 4 pore-forming subunits. The purpose of this study was to explore the heteromerization of TRP subunits crossing different TRP subfamilies. Two-step coimmunoprecipitation (co-IP) and fluorescence resonance energy transfer (FRET) were used to determine the interaction of the different TRP subunits. Patch-clamp and cytosolic Ca(2+) measurements were used to determine the functional role of the ion channels in flow conditions. The analysis demonstrated the formation of a heteromeric TRPV4-C1-P2 complex in primary cultured rat mesenteric artery endothelial cells (MAECs) and HEK293 cells that were cotransfected with TRPV4, TRPC1, and TRPP2. In functional experiments, pore-dead mutants for each of these 3 TRP isoforms nearly abolished the flow-induced cation currents and Ca(2+) increase, suggesting that all 3 TRPs contribute to the ion permeation pore of the channels. We identified the first heteromeric TRP channels composed of subunits from 3 different TRP subfamilies. Functionally, this heteromeric TRPV4-C1-P2 channel mediates the flow-induced Ca(2+) increase in native vascular endothelial cells.
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Affiliation(s)
- Juan Du
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China; Department of Physiology, Anhui Medical University, He Fei, China; and
| | - Xin Ma
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Bing Shen
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China; Department of Physiology, Anhui Medical University, He Fei, China; and
| | - Yu Huang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Lutz Birnbaumer
- National Institute of Environmental Health Sciences, U.S. National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Xiaoqiang Yao
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China;
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19
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González C, Baez-Nieto D, Valencia I, Oyarzún I, Rojas P, Naranjo D, Latorre R. K(+) channels: function-structural overview. Compr Physiol 2013; 2:2087-149. [PMID: 23723034 DOI: 10.1002/cphy.c110047] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Potassium channels are particularly important in determining the shape and duration of the action potential, controlling the membrane potential, modulating hormone secretion, epithelial function and, in the case of those K(+) channels activated by Ca(2+), damping excitatory signals. The multiplicity of roles played by K(+) channels is only possible to their mammoth diversity that includes at present 70 K(+) channels encoding genes in mammals. Today, thanks to the use of cloning, mutagenesis, and the more recent structural studies using x-ray crystallography, we are in a unique position to understand the origins of the enormous diversity of this superfamily of ion channels, the roles they play in different cell types, and the relations that exist between structure and function. With the exception of two-pore K(+) channels that are dimers, voltage-dependent K(+) channels are tetrameric assemblies and share an extremely well conserved pore region, in which the ion-selectivity filter resides. In the present overview, we discuss in the function, localization, and the relations between function and structure of the five different subfamilies of K(+) channels: (a) inward rectifiers, Kir; (b) four transmembrane segments-2 pores, K2P; (c) voltage-gated, Kv; (d) the Slo family; and (e) Ca(2+)-activated SK family, SKCa.
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Affiliation(s)
- Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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20
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Endothelial Insulin-Like Growth Factor-1 Modulates Proliferation and Phenotype of Smooth Muscle Cells Induced by Low Shear Stress. Ann Biomed Eng 2013; 42:776-86. [DOI: 10.1007/s10439-013-0957-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 11/29/2013] [Indexed: 11/30/2022]
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21
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Takai J, Santu A, Zheng H, Koh SD, Ohta M, Filimban LM, Lemaître V, Teraoka R, Jo H, Miura H. Laminar shear stress upregulates endothelial Ca²⁺-activated K⁺ channels KCa2.3 and KCa3.1 via a Ca²⁺/calmodulin-dependent protein kinase kinase/Akt/p300 cascade. Am J Physiol Heart Circ Physiol 2013; 305:H484-93. [PMID: 23792675 DOI: 10.1152/ajpheart.00642.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In endothelial cells (ECs), Ca²⁺-activated K⁺ channels KCa2.3 and KCa3.1 play a crucial role in the regulation of arterial tone via producing NO and endothelium-derived hyperpolarizing factors. Since a rise in intracellular Ca²⁺ levels and activation of p300 histone acetyltransferase are early EC responses to laminar shear stress (LS) for the transcriptional activation of genes, we examined the role of Ca²⁺/calmodulin-dependent kinase kinase (CaMKK), the most upstream element of a Ca²⁺/calmodulin-kinase cascade, and p300 in LS-dependent regulation of KCa2.3 and KCa3.1 in ECs. Exposure to LS (15 dyn/cm²) for 24 h markedly increased KCa2.3 and KCa3.1 mRNA expression in cultured human coronary artery ECs (3.2 ± 0.4 and 45 ± 10 fold increase, respectively; P < 0.05 vs. static condition; n = 8-30), whereas oscillatory shear (OS; ± 5 dyn/cm² × 1 Hz) moderately increased KCa3.1 but did not affect KCa2.3. Expression of KCa2.1 and KCa2.2 was suppressed under both LS and OS conditions, whereas KCa1.1 was slightly elevated in LS and unchanged in OS. Inhibition of CaMKK attenuated LS-induced increases in the expression and channel activity of KCa2.3 and KCa3.1, and in phosphorylation of Akt (Ser473) and p300 (Ser1834). Inhibition of Akt abolished the upregulation of these channels by diminishing p300 phosphorylation. Consistently, disruption of the interaction of p300 with transcription factors eliminated the induction of these channels. Thus a CaMKK/Akt/p300 cascade plays an important role in LS-dependent induction of KCa2.3 and KCa3.1 expression, thereby regulating EC function and adaptation to hemodynamic changes.
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Affiliation(s)
- Jun Takai
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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22
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Vickers DAL, Chory EJ, Harless MC, Murthy SK. p38 signaling and receptor recycling events in a microfluidic endothelial cell adhesion assay. PLoS One 2013; 8:e65828. [PMID: 23762436 PMCID: PMC3676332 DOI: 10.1371/journal.pone.0065828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/01/2013] [Indexed: 01/13/2023] Open
Abstract
Adhesion-based microfluidic cell separation has proven to be very useful in applications ranging from cancer diagnostics to tissue engineering. This process involves functionalizing microchannel surfaces with a capture molecule. High specificity and purity capture can be achieved using this method. Despite these advances, little is known about the mechanisms that govern cell capture within these devices and their relationships to basic process parameters such as fluid shear stress and the presence of soluble factors. This work examines how the adhesion of human endothelial cells (ECs) is influenced by a soluble tetrapeptide, Arg-Glu-Asp-Val (REDV) and fluidic shear stress. The ability of these ECs to bind within microchannels coated with REDV is shown to be governed by shear- and soluble-factor mediated changes in p38 mitogen-activated protein kinase expression together with recycling of adhesion receptors from the endosome.
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Affiliation(s)
- Dwayne A. L. Vickers
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, United States of America
| | - Emma J. Chory
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, United States of America
| | - Megan C. Harless
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, United States of America
| | - Shashi K. Murthy
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts, United States of America
- Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts, United States of America
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23
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Ruder WC, Pratt ED, Brandy NZD, LaVan DA, LeDuc PR, Antaki JF. Calcium signaling is gated by a mechanical threshold in three-dimensional environments. Sci Rep 2012; 2:554. [PMID: 22870383 PMCID: PMC3412325 DOI: 10.1038/srep00554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/05/2012] [Indexed: 01/16/2023] Open
Abstract
Cells interpret their mechanical environment using diverse signaling pathways that affect complex phenotypes. These pathways often interact with ubiquitous 2nd-messengers such as calcium. Understanding mechanically-induced calcium signaling is especially important in fibroblasts, cells that exist in three-dimensional fibrous matrices, sense their mechanical environment, and remodel tissue morphology. Here, we examined calcium signaling in fibroblasts using a minimal-profile, three-dimensional (MP3D) mechanical assay system, and compared responses to those elicited by conventional, two-dimensional magnetic tensile cytometry and substratum stretching. Using the MP3D system, we observed robust mechanically-induced calcium responses that could not be recreated using either two-dimensional technique. Furthermore, we used the MP3D system to identify a critical displacement threshold governing an all-or-nothing mechanically-induced calcium response. We believe these findings significantly increase our understanding of the critical role of calcium signaling in cells in three-dimensional environments with broad implications in development and disease.
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Affiliation(s)
- Warren C Ruder
- Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
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24
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Du J, Wong WY, Sun L, Huang Y, Yao X. Protein kinase G inhibits flow-induced Ca2+ entry into collecting duct cells. J Am Soc Nephrol 2012; 23:1172-80. [PMID: 22518003 DOI: 10.1681/asn.2011100972] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The renal cortical collecting duct (CCD) contributes to the maintenance of K(+) homeostasis by modulating renal K(+) secretion. Cytosolic Ca(2+) ([Ca(2+)](i)) mediates flow-induced K(+) secretion in the CCD, but the mechanisms regulating flow-induced Ca(2+) entry into renal epithelial cells are not well understood. Here, we found that atrial natriuretic peptide, nitric oxide, and cyclic guanosine monophosphate (cGMP) act through protein kinase G (PKG) to inhibit flow-induced increases in [Ca(2+)](i) in M1-CCD cells. Coimmunoprecipitation, double immunostaining, and functional studies identified heteromeric TRPV4-P2 channels as the mediators of flow-induced Ca(2+) entry into M1-CCD cells and HEK293 cells that were coexpressed with both TRPV4 and TRPP2. In these HEK293 cells, introducing point mutations at two putative PKG phosphorylation sites on TRPP2 abolished the ability of cGMP to inhibit flow-induced Ca(2+) entry. In addition, treating M1-CCD cells with fusion peptides that compete with the endogenous PKG phosphorylation sites on TRPP2 also abolished the cGMP-mediated inhibition of the flow-induced Ca(2+) entry. Taken together, these data suggest that heteromeric TRPV4-P2 channels mediate the flow-induced entry of Ca(2+) into collecting duct cells. Furthermore, substances such as atrial natriuretic peptide and nitric oxide, which increase cGMP, abrogate flow-induced Ca(2+) entry through PKG-mediated inhibition of these channels.
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Affiliation(s)
- Juan Du
- School of Biomedical Sciences, Chinese University of Hong Kong, China
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25
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Abstract
Several apparent paradoxes are evident when one compares mathematical predictions from models of nitric oxide (NO) diffusion and convection in vasculature structures with experimental measurements of NO (or related metabolites) in animal and human studies. Values for NO predicted from mathematical models are generally much lower than in vivo NO values reported in the literature for experiments, specifically with NO microelectrodes positioned at perivascular locations next to different sizes of blood vessels in the microcirculation and NO electrodes inserted into a wide range of tissues supplied by the microcirculation of each specific organ system under investigation. There continues to be uncertainty about the roles of NO scavenging by hemoglobin versus a storage function that may conserve NO, and other signaling targets for NO need to be considered. This review describes model predictions and relevant experimental data with respect to several signaling pathways in the microcirculation that involve NO.
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26
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Sandow SL, Senadheera S, Grayson TH, Welsh DG, Murphy TV. Calcium and endothelium-mediated vasodilator signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:811-31. [PMID: 22453971 DOI: 10.1007/978-94-007-2888-2_36] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Vascular tone refers to the balance between arterial constrictor and dilator activity. The mechanisms that underlie tone are critical for the control of haemodynamics and matching circulatory needs with metabolism, and thus alterations in tone are a primary factor for vascular disease etiology. The dynamic spatiotemporal control of intracellular Ca(2+) levels in arterial endothelial and smooth muscle cells facilitates the modulation of multiple vascular signaling pathways. Thus, control of Ca(2+) levels in these cells is integral for the maintenance of tone and blood flow, and intimately associated with both physiological and pathophysiological states. Hence, understanding the mechanisms that underlie the modulation of vascular Ca(2+) activity is critical for both fundamental knowledge of artery function, and for the development of targeted therapies. This brief review highlights the role of Ca(2+) signaling in vascular endothelial function, with a focus on contact-mediated vasodilator mechanisms associated with endothelium-derived hyperpolarization and the longitudinal conduction of responses over distance.
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Affiliation(s)
- Shaun L Sandow
- Department of Physiology, School of Medical Sciences, University of New South Wales, 2052 Sydney, NSW, Australia.
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27
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Liu B, Lu S, Zheng S, Jiang Z, Wang Y. Two distinct phases of calcium signalling under flow. Cardiovasc Res 2011; 91:124-33. [PMID: 21285296 DOI: 10.1093/cvr/cvr033] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIMS High shear stress (HSS) can have significant impact on angiogenesis and atherosclerosis in collateral arteries near the bifurcation and curvature regions. Here, we investigate the spatiotemporal pattern of HSS-induced intracellular calcium alteration. METHODS AND RESULTS Genetically encoded biosensors based on fluorescence resonance energy transfer were targeted in the cytoplasm and the endoplasmic reticulum (ER) to visualize the subcellular calcium dynamics in bovine aortic endothelial cells under HSS (65 dyn/cm(2)). Upon HSS application, the intracellular Ca(2+) concentration ([Ca(2+)](i)) increased immediately and maintained a sustained high level, while the ER-stored calcium had a significant decrease only after 300 s. The perturbation of calcium influx across the plasma membrane (PM) by the removal of extracellular calcium or the blockage of membrane channels inhibited the early phase of [Ca(2+)](i) increase upon HSS application, which was further shown to be sensitive to the magnitudes of shear stress and the integrity of cytoskeletal support. In contrast, Src, phospholipase C(PLC), and the inositol 1,4,5-trisphosphate receptor (IP(3)R) can regulate the late phase of HSS-induced [Ca(2+)](i) increase via the promotion of the ER calcium efflux. CONCLUSION The HSS-induced [Ca(2+)](i) increase consists of two well-co-ordinated phases with different sources and mechanisms: (i) an early phase due to the calcium influx across the PM which is dependent on the mechanical impact and cytoskeletal support and (ii) a late phase originated from the ER-calcium efflux which is regulated by the Src, PLC, and IP(3)R signalling pathway. Therefore, our work presented new molecular-level insights into systematic understanding of mechanotransduction in cardiovascular systems.
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Affiliation(s)
- Bo Liu
- Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
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PDGF-BB and TGF-{beta}1 on cross-talk between endothelial and smooth muscle cells in vascular remodeling induced by low shear stress. Proc Natl Acad Sci U S A 2011; 108:1908-13. [PMID: 21245329 DOI: 10.1073/pnas.1019219108] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Shear stress, especially low shear stress (LowSS), plays an important role in vascular remodeling during atherosclerosis. Endothelial cells (ECs), which are directly exposed to shear stress, convert mechanical stimuli into intracellular signals and interact with the underlying vascular smooth muscle cells (VSMCs). The interactions between ECs and VSMCs modulate the LowSS-induced vascular remodeling. With the use of proteomic analysis, the protein profiles of rat aorta cultured under LowSS (5 dyn/cm(2)) and normal shear stress (15 dyn/cm(2)) were compared. By using Ingenuity Pathway Analysis to identify protein-protein association, a network was disclosed that involves two secretary molecules, PDGF-BB and TGF-β1, and three other linked proteins, lamin A, lysyl oxidase, and ERK 1/2. The roles of this network in cellular communication, migration, and proliferation were further studied in vitro by a cocultured parallel-plate flow chamber system. LowSS up-regulated migration and proliferation of ECs and VSMCs, increased productions of PDGF-BB and TGF-β1, enhanced expressions of lysyl oxidase and phospho-ERK1/2, and decreased Lamin A in ECs and VSMCs. These changes induced by LowSS were confirmed by using PDGF-BB recombinant protein, siRNA, and neutralizing antibody. TGF-β1 had similar influences on ECs as PDGF-BB, but not on VSMCs. Our results suggest that ECs convert the LowSS stimuli into up-regulations of PDGF-BB and TGF-β1, but these two factors play different roles in LowSS-induced vascular remodeling. PDGF-BB is involved in the paracrine control of VSMCs by ECs, whereas TGF-β1 participates in the feedback control from VSMCs to ECs.
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Ma KT, Guan BC, Yang YQ, Nuttall AL, Jiang ZG. 2-Aminoethoxydiphenyl borate blocks electrical coupling and inhibits voltage-gated K+ channels in guinea pig arteriole cells. Am J Physiol Heart Circ Physiol 2010; 300:H335-46. [PMID: 21037232 DOI: 10.1152/ajpheart.00737.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
2-Aminoethoxydiphenyl borate (2-APB) analogs are potentially better vascular gap junction blockers than others widely used, but they remain to be characterized. Using whole cell and intracellular recording techniques, we studied the actions of 2-APB and its potent analog diphenylborinic anhydride (DPBA) on vascular smooth muscle cells (VSMCs) and endothelial cells in situ of or dissociated from arteriolar segments of the cochlear spiral modiolar artery, brain artery, and mesenteric artery. We found that both 2-APB and DPBA reversibly suppressed the input conductance (G(input)) of in situ VSMCs (IC(50) ≈ 4-8 μM). Complete electrical isolation of the recorded VSMC was achieved at 100 μM. A similar gap junction blockade was observed in endothelial cell tubules of the spiral modiolar artery. Similar to the action of 18β-glycyrrhetinic acid (18β-GA), 2-APB and DPBA depolarized VSMCs. In dissociated VSMCs, 2-APB and DPBA inhibited the delayed rectifier K(+) current (I(K)) with an IC(50) of ∼120 μM in the three vessels but with no significant effect on G(input) or the current-voltage relation between -140 and -40 mV. 2-APB inhibition of I(K) was more pronounced at potentials of ≤20 mV than at +40 mV and more marked on the fast component than on the slow component, which was mimicked by 4-aminopyridine but not by tetraethylammonium, nitrendipine, or charybdotoxin. In contrast, 18β-GA caused a linear inhibition of I(K) between 0 to +40 mV, which was similar to the action of tetraethylammonium or charybdotoxin. Finally, the 2-APB-induced inhibition of electrical coupling and I(K) was not affected by the inositol 1,4,5-trisphosphate receptor antagonist xestospongin C. We conclude that 2-APB analogs are a class of potent and reversible vascular gap junction blockers with a weak side effect of voltage-gated K(+) channel inhibition. They could be gap junction blockers superior to 18β-GA only when Ca(2+)-actived K(+) channel inhibition by the latter is a concern but inositol 1,4,5-trisphosphate receptor and voltage-gated K(+) channel inhibitions are not.
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Affiliation(s)
- Ke-Tao Ma
- Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon 97239, USA
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Ma X, Cao J, Luo J, Nilius B, Huang Y, Ambudkar IS, Yao X. Depletion of intracellular Ca2+ stores stimulates the translocation of vanilloid transient receptor potential 4-c1 heteromeric channels to the plasma membrane. Arterioscler Thromb Vasc Biol 2010; 30:2249-55. [PMID: 20705915 DOI: 10.1161/atvbaha.110.212084] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To examine the effect of Ca(2+) store depletion on the translocation of vanilloid transient receptor potential (TRPV) 4-C1 heteromeric channels to the plasma membrane. METHODS AND RESULTS Vesicular trafficking is a key mechanism for controlling the surface expression of TRP channels in the plasma membrane, where they perform their function. TRP channels in vivo are often composed of heteromeric subunits. Experiments using total internal fluorescence reflection microscopy and biotin surface labeling show that Ca(2+) store depletion enhanced TRPV4-C1 translocation into the plasma membrane in human embryonic kidney 293 cells that were coexpressed with TRPV4 and canonical transient receptor potential 1 (TRPC1). Fluorescent Ca(2+) measurement and patch clamp studies demonstrated that Ca(2+) store depletion enhanced 4α-PDD-stimulated Ca(2+) influx and cation current. The translocation required stromal interacting molecule 1 (STIM1). TRPV4-C1 heteromeric channels were more favorably translocated to the plasma membrane than TRPC1 or TRPV4 homomeric channels. Similar results were obtained in native vascular endothelial cells. CONCLUSIONS Ca(2+) store depletion stimulates the insertion of TRPV4-C1 heteromeric channels into the plasma membrane, resulting in an augmented Ca(2+) influx in response to flow in the human embryonic kidney cell overexpression system and native endothelial cells.
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Affiliation(s)
- Xin Ma
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
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31
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Ma X, Qiu S, Luo J, Ma Y, Ngai CY, Shen B, Wong CO, Huang Y, Yao X. Functional Role of Vanilloid Transient Receptor Potential 4-Canonical Transient Receptor Potential 1 Complex in Flow-Induced Ca
2+
Influx. Arterioscler Thromb Vasc Biol 2010; 30:851-8. [DOI: 10.1161/atvbaha.109.196584] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Objective—
The present study is aimed at investigating the interaction of TRPV4 with TRPC1 and the functional role of such an interaction in flow-induced Ca
2+
influx. Hemodynamic blood flow is an important physiological factor that modulates vascular tone. One critical early event in this process is a cytosolic Ca
2+
([Ca
2+
]
i
) rise in endothelial cells in response to flow.
Methods and Results—
With the use of fluorescence resonance energy transfer, coimmunoprecipitation, and subcellular colocalization methods, it was found that TRPC1 interacts physically with TRPV4 to form a complex. In functional studies, flow elicited a transient [Ca
2+
]
i
increase in TRPV4-expressing human embryonic kidney (HEK) 293 cells. Coexpression of TRPC1 with TRPV4 markedly prolonged this [Ca
2+
]
i
transient; it also enabled this [Ca
2+
]
i
transient to be negatively modulated by protein kinase G. Furthermore, this flow-induced [Ca
2+
]
i
increase was markedly inhibited by anti–TRPC1-blocking antibody T1E3 and a dominant-negative construct TRPC1Δ567-793 in TRPV4-C1–coexpressing HEK cells and human umbilical vein endothelial cells. T1E3 also inhibited flow-induced vascular dilation in isolated rat small mesenteric artery segments.
Conclusion—
This study shows that TRPC1 interacts physically with TRPV4 to form a complex, and this TRPV4-C1 complex may mediate flow-induced Ca
2+
influx in vascular endothelial cells. The association of TRPC1 with TRPV4 prolongs the flow-induced [Ca
2+
]
i
transient, and it also enables this [Ca
2+
]
i
transient to be negatively modulated by protein kinase G. This TRPV4-C1 complex plays a key role in flow-induced endothelial Ca
2+
influx.
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Affiliation(s)
- Xin Ma
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Shuang Qiu
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhong Luo
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Ma
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Ching-Yuen Ngai
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Bing Shen
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Ching-on Wong
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Huang
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoqiang Yao
- From the Li Ka Shing Institute of Health Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; the School of Biomedical Sciences (X.M., Y.M., C.-Y.N., B.S., C.-o.W., Y.H., and X.Y.), Chinese University of Hong Kong, Hong Kong; and the Department of Neurobiology (S.Q. and J.L.), Zhejiang University School of Medicine, Hangzhou, China
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Hibino H, Inanobe A, Furutani K, Murakami S, Findlay I, Kurachi Y. Inwardly rectifying potassium channels: their structure, function, and physiological roles. Physiol Rev 2010; 90:291-366. [PMID: 20086079 DOI: 10.1152/physrev.00021.2009] [Citation(s) in RCA: 1070] [Impact Index Per Article: 76.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K(+) channels (Kir6.x) are tightly linked to cellular metabolism, and K(+) transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). Inward rectification results from pore block by intracellular substances such as Mg(2+) and polyamines. Kir channel activity can be modulated by ions, phospholipids, and binding proteins. The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH(2) and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.
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Affiliation(s)
- Hiroshi Hibino
- Department of Pharmacology, Graduate School of Medicine and The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka 565-0871, Japan
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Fernandez-Rodriguez S, Edwards DH, Newton B, Griffith TM. Attenuated store-operated Ca2+ entry underpins the dual inhibition of nitric oxide and EDHF-type relaxations by iodinated contrast media. Cardiovasc Res 2009; 84:470-8. [DOI: 10.1093/cvr/cvp239] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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34
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Singh RB, Elimban V, Dhalla NS. Differences in ischemia-reperfusion-induced endothelial changes in hearts perfused at constant flow and constant pressure. J Appl Physiol (1985) 2008; 105:1779-87. [DOI: 10.1152/japplphysiol.00076.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Isolated hearts subjected to ischemia-reperfusion (I/R) exhibit depressed cardiac performance and alterations in subcellular function. Since hearts perfused at constant flow (CF) and constant pressure (CP) show differences in their contractile response to I/R, this study was undertaken to examine mechanisms responsible for these I/R-induced alterations in CF-perfused and CP-perfused hearts. Rat hearts, perfused at CF (10 ml/min) or CP (80 mmHg), were subjected to I/R (30 min global ischemia followed by 60 min reperfusion), and changes in cardiac function as well as sarcolemmal (SL) Na+-K+-ATPase activity, sarcoplasmic reticulum (SR) Ca2+uptake, and endothelial function were monitored. The I/R-induced depressions in cardiac function, SL Na+-K+-ATPase, and SR Ca2+-uptake activities were greater in hearts perfused at CF than in hearts perfused at CP. In hearts perfused at CF, I/R-induced increase in calpain activity and decrease in nitric oxide (NO) synthase (endothelial NO synthase) protein content in the heart as well as decrease in NO concentration of the perfusate were greater than in hearts perfused at CP. These changes in contractile activity and biochemical parameters due to I/R in hearts perfused at CF were attenuated by treatment with l-arginine, a substrate for NO synthase, while those in hearts perfused at CP were augmented by treatment with NG-nitro-l-arginine methyl ester, an inhibitor of NO synthase. The results indicate that the I/R-induced differences in contractile responses and alterations in subcellular organelles between hearts perfused at CF and CP may partly be attributed to greater endothelial dysfunction in CF-perfused hearts than that in CP-perfused hearts.
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35
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Comerford A, Plank MJ, David T. Endothelial nitric oxide synthase and calcium production in arterial geometries: an integrated fluid mechanics/cell model. J Biomech Eng 2008; 130:011010. [PMID: 18298186 DOI: 10.1115/1.2838026] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is well known that atherosclerosis occurs at very specific locations throughout the human vasculature, such as arterial bifurcations and bends, all of which are subjected to low wall shear stress. A key player in the pathology of atherosclerosis is the endothelium, controlling the passage of material to and from the artery wall. Endothelial dysfunction refers to the condition where the normal regulation of processes by the endothelium is diminished. In this paper, the blood flow and transport of the low diffusion coefficient species adenosine triphosphate (ATP) are investigated in a variety of arterial geometries: a bifurcation with varying inner angle, and an artery bend. A mathematical model of endothelial calcium and endothelial nitric oxide synthase cellular dynamics is used to investigate spatial variations in the physiology of the endothelium. This model allows assessment of regions of the artery wall deficient in nitric oxide (NO). The models here aim to determine whether 3D flow fields are important in determining ATP concentration and endothelial function. For ATP transport, the effects of a coronary and carotid wave form on mass transport is investigated for low Womersley number. For the carotid, the Womersley number is then increased to determine whether this is an important factor. The results show that regions of low wall shear stress correspond with regions of impaired endothetial nitric oxide synthase signaling, therefore reduced availability of NO. However, experimental work is required to determine if this level is significant. The results also suggest that bifurcation angle is an important factor and acute angle bifurcations are more susceptible to disease than large angle bifurcations. It has been evidenced that complex 3D flow fields play an important role in determining signaling within endothelial cells. Furthermore, the distribution of ATP in blood is highly dependent on secondary flow features. The models here use ATP concentration simulated under steady conditions. This has been evidenced to reproduce essential features of time-averaged ATP concentration over a cardiac cycle for small Womersley numbers. However, when the Womersley number is increased, some differences are observed. Transient variations are overall insignificant, suggesting that spatial variation is more important than temporal. It has been determined that acute angle bifurcations are potentially more susceptible to atherogenesis and steady-state ATP transport reproduces essential features of time-averaged pulsatile transport for small Womersley number. Larger Womersley numbers appear to be an important factor in time-dependent mass transfer.
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Affiliation(s)
- A Comerford
- Centre for Bioengineering, University of Canterbury, Christchurch, New Zealand
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36
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Berra-Romani R, Raqeeb A, Avelino-Cruz JE, Moccia F, Oldani A, Speroni F, Taglietti V, Tanzi F. Ca2+ signaling in injured in situ endothelium of rat aorta. Cell Calcium 2008; 44:298-309. [PMID: 18276005 DOI: 10.1016/j.ceca.2007.12.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2007] [Revised: 11/20/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
Abstract
The inner wall of excised rat aorta was scraped by a microelectrode and Ca2+ signals were investigated by fluorescence microscopy in endothelial cells (ECs) directly coupled with injured cells. The injury caused an immediate increase in the intracellular Ca2+ concentration ([Ca2+]i), followed by a long-lasting decay phase due to Ca2+ influx from extracellular space. The immediate response was mainly due to activation of purinergic receptors, as shown by the effect of P2X and P2Y receptors agonists and antagonists, such as suramin, alpha,beta-MeATP, MRS-2179 and 2-MeSAMP. Inhibition of store-operated Ca2+ influx did not affect either the peak response or the decay phase. Furthermore, the latter was: (i) insensitive to phospholipase C inhibition, (ii) sensitive to the gap junction blockers, palmitoleic acid, heptanol, octanol and oleamide, and (iii) sensitive to La3+ and Ni2+, but not to Gd3+. Finally, ethidium bromide or Lucifer Yellow did not enter ECs facing the scraped area. These results suggest that endothelium scraping: (i) causes a short-lasting stimulation of healthy ECs by extracellular nucleotides released from damaged cells and (ii) uncouples the hemichannels of the ECs facing the injury site; these hemichannels do not fully close and allow a long-lasting Ca2+ entry.
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Affiliation(s)
- Roberto Berra-Romani
- Department of Physiological and Pharmacological Sciences, University of Pavia, V. Forlanini 6, 27100 Pavia, Italy
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37
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Sbrana S, Della Pina F, Rizza A, Buffa M, De Filippis R, Gianetti J, Clerico A. Relationships between optical aggregometry (type born) and flow cytometry in evaluating ADP-induced platelet activation. CYTOMETRY PART B-CLINICAL CYTOMETRY 2008; 74:30-9. [PMID: 17630652 DOI: 10.1002/cyto.b.20360] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Platelet response to activating agents is used to monitor the efficacy of anti-aggregation therapies. The aim of our study has been to demonstrate the existence of relationships between early events of ADP-induced platelet activation, measured by flow cytometry and platelet-rich plasma aggregation, quantified by optical aggregometry. METHODS We evaluated peripheral blood of 12 donors. The following parameters were quantified by cytometry after stimulation with adenosine diphosphate (ADP) (0.5, 1, 2, 5, 10, 20 muM): CD62P (P-selectin) and PAC-1 expression, and cytosolic Ca(2+) mobilization. Aggregation was measured by optical aggregometry. We also studied 13 patients, undergoing coronary stenting, treated with aspirin (before procedure) or with aspirin plus clopidogrel (after procedure). We evaluated CD62P and PAC-1 expression, aggregation, and vasodilator-stimulated phopshoprotein phosphorylation (platelet reactivity index, PRI). RESULTS Flow procedures were more sensitive than aggregometry, with a lowest interindividual variability. Linear relationships existed in donors between CD62P expression and Ca(2+) mobilization (P < 0.0001), and between aggregation and Ca(2+) mobilization (P < 0.0001). Linear relationships existed between aggregation and CD62P expression, as percentage (P < 0.0001), or relative fluorescence intensity (RFI) (P < 0.0001). Exponential equations related aggregation and PAC-1 expression, as percentage (P < 0.0001), or RFI (P < 0.0001). Linear relationships between aggregation and CD62P expression (as percentage) existed in the patients before (P = 0.0022) and after procedure (P = 0.0020). Exponential relationships between aggregation and PAC-1 expression (as percentage) existed before (P = 0.0012) and after procedure (P = 0.0024). Linear correlations related aggregation response predicted on CD62P expression, and measured aggregation inhibition after clopidogrel (P = 0.0013) as well as predicted aggregation and PRI inhibition (P = 0.0031). CONCLUSIONS Tight relationships between aggregation and cytometric quantification of platelet markers in whole blood, in particular CD62P, allow to predict aggregation response to ADP from flow data in patients treated with aspirin alone or with aspirin plus clopidogrel.
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Affiliation(s)
- Silverio Sbrana
- Laboratory of Hematology and Flow Cytometry, CNR Institute of Clinical Physiology, Massa, Italy.
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38
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Jie H, Donghua H, Xingkui X, Liang G, Wenjun W, Xiaoyan H, Zhen C. Homoharringtonine-induced apoptosis of MDS cell line MUTZ-1 cells is mediated by the endoplasmic reticulum stress pathway. Leuk Lymphoma 2007; 48:964-77. [PMID: 17487741 DOI: 10.1080/10428190701216360] [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] [Indexed: 01/10/2023]
Abstract
Homoharringtonine has been shown to lead to apoptosis of leukemic cells in several studies. Here we showed that the endoplasmic reticulum (ER) may be the initial site of apoptotic signal induced by homoharringtonine in MUTZ-1 cells. After incubation with homoharringtonine, the percentage of apoptotic MUTZ-1 cells increased in a time-dependent manner, Ca(2+) translocated from ER pool to cytosol, the mitochondrial membrane potential decreased, and Bid protein translocated from ER to mitochondria. The activation of ER stress-associated proapoptotic factor CHOP and ER chaperones BiP and XBP1 genes followed by cleavage of caspase-3 but not caspase-4 protein were also observed.
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Affiliation(s)
- Hu Jie
- Department of Hematology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
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39
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Miyazaki T, Honda K, Ohata H. Modulation of Ca2+ transients in cultured endothelial cells in response to fluid flow through alphav integrin. Life Sci 2007; 81:1421-30. [PMID: 17931663 DOI: 10.1016/j.lfs.2007.08.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 08/28/2007] [Accepted: 08/31/2007] [Indexed: 11/30/2022]
Abstract
In order to determine whether integrin dynamics is associated with intracellular Ca(2+) concentration ([Ca(2+)](i)) mobilization in ECs in response to hemodynamic forces, changes in [Ca(2+)](i) in fluo-4-loaded cultured bovine aortic endothelial cells (BAECs) under fluid flow conditions were visualized employing laser scanning confocal microscopy. Following the onset of flow stimulus, transient increases in [Ca(2+)](i) occurred several times in individual BAECs during the 30-min observation period. The frequency of these [Ca(2+)](i) transients was clearly reduced by the application of an integrin antagonist (GRGDSP peptide). Furthermore, treatment of cells with an integrin activator (Mn(2+)) resulted in reduction of peak [Ca(2+)](i) levels and elevated frequency, which was markedly rescued upon GRGDSP administration. In contrast, an actin de-polymerizing agent (cytochalasin D) exerted no inhibitory effects; rather, cytochalasin D more likely facilitated [Ca(2+)](i) transients. Moreover, [Ca(2+)](i) transients, which were suppressed by short interference RNA-induced silencing of alphav integrin, exhibited greater frequently in cells cultured on vitronectin substratum in comparison with those cultured on fibronectin or collagen substratum. Either removal of extracellular Ca(2+), application of an inhibitor of endoplasmic reticulum Ca(2+)-ATPase (thapsigargin) or non-selective cation channel blocker (La(3+)) inhibited the [Ca(2+)](i) transients. Additionally, [Ca(2+)](i) transients were attenuated by extracellular signal-regulated kinase (ERK) kinase inhibitor (U0126); in contrast, [Ca(2+)](i) transients were unaffected by tyrosine kinase inhibitor (genistein) or phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002). Therefore, our findings revealed that alphav integrin dynamics modulates the frequency of flow-induced [Ca(2+)](i) transients in BAECs in an ERK-dependent fashion.
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Affiliation(s)
- Takuro Miyazaki
- Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
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40
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Abstract
This chapter reviews recent evidence indicating that canonical or classical transient receptor potential (TRPC) channels are directly or indirectly mechanosensitive (MS) and can therefore be designated as mechano-operated channels (MOCs). The MS functions of TRPCs may be mechanistically related to their better known functions as store-operated and receptor-operated channels (SOCs and ROCs). Mechanical forces may be conveyed to TRPC channels through the "conformational coupling" mechanism that transmits information regarding the status of internal Ca(2+) stores. All TRPCs are regulated by receptors coupled to phospholipases that are themselves MS and can regulate channels via lipidic second messengers. Accordingly, there may be several nonexclusive mechanisms by which mechanical forces may regulate TRPC channels, including direct sensitivity to bilayer mechanics, physical coupling to internal membranes and/or cytoskeletal proteins, and sensitivity to lipidic second messengers generated by MS enzymes. Various strategies that can be used for separating out different MS-gating mechanisms and their possible role in specific TRPCs are discussed.
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Affiliation(s)
- Owen P Hamill
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Rosario Maroto
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
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41
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Abstract
Elevations in cytosolic Ca2+ concentration are the usual initial response of endothelial cells to hormonal and chemical transmitters and to changes in physical parameters, and many endothelial functions are dependent upon changes in Ca2+ signals produced. Endothelial cell Ca2+ signalling shares similar features with other electrically non-excitable cell types, but has features unique to endothelial cells. This chapter discusses the major components of endothelial cell Ca2+ signalling.
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Affiliation(s)
- Q K Tran
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA
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42
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Liu C, Ngai CY, Huang Y, Ko WH, Wu M, He GW, Garland CJ, Dora KA, Yao X. Depletion of intracellular Ca2+ stores enhances flow-induced vascular dilatation in rat small mesenteric artery. Br J Pharmacol 2006; 147:506-15. [PMID: 16415911 PMCID: PMC1616973 DOI: 10.1038/sj.bjp.0706639] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effect of depleting intracellular Ca2+ stores on flow-induced vascular dilatation and the mechanism responsible for the vasodilatation were examined in rat isolated small mesenteric arteries. The arteries were pressurized to 50 mmHg and preconstricted with phenylephrine. Intraluminal flow reversed the effect of phenylephrine, resulting in vasodilatation. Flow dilatation consisted of an initial transient peak followed by a sustained plateau phase. The magnitude of dilatation was markedly reduced by removing Ca2+ from the intraluminal flow medium. Depletion of intracellular Ca2+ stores with either cyclopiazonic acid (CPA, 2 microM) or 1,4-dihydroxy-2,5-di-tert-butylbenzene (BHQ, 10 microM) significantly augmented the magnitude of flow dilatation. Flow-induced endothelial cell Ca2+ influx was also markedly enhanced in arteries pretreated with CPA or BHQ.Flow-induced dilatation was insensitive to Nw-nitro-L-arginine methyl ester (100 microM) plus indomethacin (3 microM) or to oxyhemoglobin (3 microM), but was markedly reduced by 30 mM extracellular K+ or 2 mM tetrabutylammonium (TBA), suggesting an involvement of EDHF. Catalase at 1200 U ml-1 abolished the flow-induced dilatation, while the application of exogenous H2O2 (90-220 microM) induced relaxation in phenylephrine-preconstricted arteries. Relaxation to exogenous H2O2 was blocked in the presence of 30 mM extracellular K+, and H2O2 (90 microM) hyperpolarized the smooth muscle cells, indicating that H2O2 can act as an EDHF. In conclusion, flow-induced dilatation in rat mesenteric arteries can be markedly enhanced by prior depletion of intracellular Ca2+ stores. Furthermore, these data are consistent with a role for H2O2 as the vasodilator involved.
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Affiliation(s)
- Cuiling Liu
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Department of Pathology, Peking University Health Science Center, Beijing, China
| | - Ching-Yuen Ngai
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing-Hung Ko
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Min Wu
- Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Guo-Wei He
- Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Kim A Dora
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY
| | - Xiaoqiang Yao
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Author for correspondence:
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43
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Hong D, Jaron D, Buerk DG, Barbee KA. Heterogeneous response of microvascular endothelial cells to shear stress. Am J Physiol Heart Circ Physiol 2006; 290:H2498-508. [PMID: 16415079 DOI: 10.1152/ajpheart.00828.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We investigated changes in calcium concentration in cultured bovine aortic endothelial cells (BAECs) and rat adrenomedulary endothelial cells (RAMECs, microvascular) in response to different levels of shear stress. In BAECs, the onset of shear stress elicited a transient increase in intracellular calcium concentration that was spatially uniform, synchronous, and dose dependent. In contrast, the response of RAMECs was heterogeneous in time and space. Shear stress induced calcium waves that originated from one or several cells and propagated to neighboring cells. The number and size of the responding groups of cells did not depend on the magnitude of shear stress or the magnitude of the calcium change in the responding cells. The initiation and the propagation of calcium waves in RAMECs were significantly suppressed under conditions in which either purinergic receptors were blocked by suramin or extracellular ATP was degraded by apyrase. Exogenously applied ATP produced similarly heterogeneous responses. The number of responding cells was dependent on ATP concentration, but the magnitude of the calcium change was not. Our data suggest that shear stress stimulates RAMECs to release ATP, causing the increase in intracellular calcium concentration via purinergic receptors in cells that are heterogeneously sensitive to ATP. The propagation of the calcium signal is also mediated by ATP, and the spatial pattern suggests a locally elevated ATP concentration in the vicinity of the initially responding cells.
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Affiliation(s)
- D Hong
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104, USA
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44
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Abstract
Among the 28 identified and unique mammalian TRP (transient receptor potential) channel isoforms, at least 19 are expressed in vascular endothelial cells. These channels appear to participate in a diverse range of vascular functions, including control of vascular tone, regulation of vascular permeability, mechanosensing, secretion, angiogenesis, endothelial cell proliferation, and endothelial cell apoptosis and death. Malfunction of these channels may result in disorders of the human cardiovascular system. All TRP channels, except for TRPM4 and TRPM5, are cation channels that allow Ca2+ influx. However, there is a daunting diversity in the mode of activation and regulation in each case. Specific TRP channels may be activated by different stimuli such as vasoactive agents, oxidative stress, mechanical stimuli, and heat. TRP channels may then transform these stimuli into changes in the cytosolic Ca2+, which are eventually coupled to various vascular responses. Evidence has been provided to suggest the involvement of at least the following TRP channels in vascular function: TRPC1, TRPC4, TRPC6, and TRPV1 in the control of vascular permeability; TRPC4, TRPV1, and TRPV4 in the regulation of vascular tone; TRPC4 in hypoxia-induced vascular remodeling; and TRPC3, TRPC4, and TRPM2 in oxidative stress-induced responses. However, in spite of the large body of data available, the functional role of many endothelial TRP channels is still poorly understood. Elucidating the mechanisms regulating the different endothelial TRP channels, and the associated development of drugs selectively to target the different isoforms, as a means to treat cardiovascular disease should, therefore, be a high priority.
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Affiliation(s)
- Xiaoqiang Yao
- Department of Physiology, Chinese University of Hong Kong, China.
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45
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Fang Y, Schram G, Romanenko VG, Shi C, Conti L, Vandenberg CA, Davies PF, Nattel S, Levitan I. Functional expression of Kir2.x in human aortic endothelial cells: the dominant role of Kir2.2. Am J Physiol Cell Physiol 2005; 289:C1134-44. [PMID: 15958527 DOI: 10.1152/ajpcell.00077.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inward rectifier K+channels (Kir) are a significant determinant of endothelial cell (EC) membrane potential, which plays an important role in endothelium-dependent vasodilatation. In the present study, several complementary strategies were applied to determine the Kir2 subunit composition of human aortic endothelial cells (HAECs). Expression levels of Kir2.1, Kir2.2, and Kir2.4 mRNA were similar, whereas Kir2.3 mRNA expression was significantly weaker. Western blot analysis showed clear Kir2.1 and Kir2.2 protein expression, but Kir2.3 protein was undetectable. Functional analysis of endothelial inward rectifier K+current ( IK) demonstrated that 1) IKcurrent sensitivity to Ba2+and pH were consistent with currents determined using Kir2.1 and Kir2.2 but not Kir2.3 and Kir2.4, and 2) unitary conductance distributions showed two prominent peaks corresponding to known unitary conductances of Kir2.1 and Kir2.2 channels with a ratio of ∼4:6. When HAECs were transfected with dominant-negative (dn)Kir2.x mutants, endogenous current was reduced ∼50% by dnKir2.1 and ∼85% by dnKir2.2, whereas no significant effect was observed with dnKir2.3 or dnKir2.4. These studies suggest that Kir2.2 and Kir2.1 are primary determinants of endogenous K+conductance in HAECs under resting conditions and that Kir2.2 provides the dominant conductance in these cells.
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Affiliation(s)
- Yun Fang
- Institute for Medicine and Engineering, University of Pennsylvania, 1160 Vagelos Research Labs, 3340 Smith Walk, Philadelphia, PA 19104, USA
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46
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Plank MJ, Wall DJN, David T. Atherosclerosis and calcium signalling in endothelial cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 91:287-313. [PMID: 16171849 DOI: 10.1016/j.pbiomolbio.2005.07.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The link between atherosclerosis and regions of disturbed flow and low wall shear stress is now firmly established, but the causal mechanisms underlying the link are not yet understood. It is now recognised that the endothelium is not simply a passive barrier between the blood and the vessel wall, but plays an active role in maintaining vascular homeostasis and participates in the onset of atherosclerosis. Calcium signalling is one of the principal intracellular signalling mechanisms by which endothelial cells (EC) respond to external stimuli, such as fluid shear stress and ligand binding. Previous studies have separately modelled mass transport of chemical species in the bloodstream and calcium dynamics in EC via the inositol trisphosphate (IP(3)) signalling pathway. We review existing models of these two phenomena, before going on to integrate the two components to provide an inclusive new model for the calcium response of the endothelium in an arbitrary vessel geometry. This enables the combined effects of fluid flow and biochemical stimulation on EC to be investigated and is the first time spatially varying, physiological fluid flow-related environmental factors have been combined with intracellular signalling in a mathematical model. Model results show that low endothelial calcium levels in the area of disturbed flow at an arterial widening may be one contributing factor to the onset of vascular disease.
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Affiliation(s)
- M J Plank
- University of Canterbury, Christchurch, New Zealand.
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47
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O'Neil RG, Heller S. The mechanosensitive nature of TRPV channels. Pflugers Arch 2005; 451:193-203. [PMID: 15909178 DOI: 10.1007/s00424-005-1424-4] [Citation(s) in RCA: 237] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2005] [Accepted: 03/28/2005] [Indexed: 01/26/2023]
Abstract
Transient receptor potential vanilloid (TRPV) channels are widely expressed in both sensory and nonsensory cells. Whereas the channels display a broad diversity to activation by chemical and physical stimuli, activation by mechanical stimuli is common to many members of this group in both lower and higher organisms. Genetic screening in Caenorhabditis elegans has demonstrated an essential role for two TRPV channels in sensory neurons. OSM-9 and OCR-2, for example, are essential for both osmosensory and mechanosensory (nose-touch) behaviors. Likewise, two Drosophila TRPV channels, NAN and IAV, have been shown to be critical for hearing by the mechanosensitive chordotonal organs located in the fly's antennae. The mechanosensitive nature of the channels appears to be conserved in higher organisms for some TRPV channels. Two vertebrate channels, TRPV2 and TRPV4, are sensitive to hypotonic cell swelling, shear stress/fluid flow (TRPV4), and membrane stretch (TRPV2). In the osmosensing neurons of the hypothalamus (circumventricular organs), TRPV4 appears to function as an osmoreceptor, or part of an osmoreceptor complex, in control of vasopressin release, whereas in inner ear hair cells and vascular baroreceptors a mechanosensory role is suggestive, but not demonstrated. Finally, in many nonsensory cells expressing TRPV4, such as vascular endothelial cells and renal tubular epithelial cells, the channel exhibits well-developed local mechanosensory transduction processes where both cell swelling and shear stress/fluid flow lead to channel activation. Hence, many TRPV channels, or combinations of TRPV channels, display a mechanosensitive nature that underlies multiple mechanosensitive processes from worms to mammals.
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Affiliation(s)
- Roger G O'Neil
- Department of Integrative Biology and Pharmacology, Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
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48
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Kalea AZ, Harris PD, Klimis-Zacas DJ. Dietary manganese suppresses α1 adrenergic receptor-mediated vascular contraction. J Nutr Biochem 2005; 16:44-9. [PMID: 15629240 DOI: 10.1016/j.jnutbio.2004.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 09/01/2004] [Accepted: 09/08/2004] [Indexed: 11/25/2022]
Abstract
We examined the effect of dietary manganese (Mn) on the vascular contractile machinery in rat thoracic aortas. Weanling male Sprague-Dawley rats were fed either an Mn-deficient (MnD), Mn-adequate (MnA) or Mn-supplemented (MnS) diet (<1, 10-15 and 45-50 ppm Mn, respectively). After 15 weeks on the diets the rats were sacrificed and 3-mm aortic rings were contracted in six cumulative doses of the alpha(1) adrenergic receptor agonist L-phenylephrine (l-Phe, 10(-8) to 3 x 10(-6) M) under 1.5-g preload and relaxed with one dose of acetylcholine (3 x 10(-6) M) to assess intact endothelium. The maximal force (F(max)) of contraction and relaxation, as well as the vessel sensitivity (pD(2)) were determined. Manganese deficiency, assessed by hepatic Mn content, significantly lowered the rate of animal growth. A two-way analysis of variance revealed that MnS animals developed lower F(max) when contracted with L-Phe compared with the MnD and MnA animals (P</=.001). Thus, dietary Mn at levels of 45-50 ppm affects the contractile machinery by reducing maximal vessel contraction to an alpha(1) adrenergic agonist. The observed pD(2) was significantly greater in the MnD group compared with the MnA and MnS animals (P</=.001). Thus, restriction of dietary Mn affects vascular sensitivity to the alpha(1) adrenergic receptor. Our results demonstrate for the first time that dietary Mn influences the receptor signaling pathways and contractile machinery of vascular smooth muscle cells in response to an alpha(1) adrenergic receptor.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Body Weight/drug effects
- Diet
- Liver/drug effects
- Male
- Manganese/administration & dosage
- Manganese/deficiency
- Manganese/pharmacology
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Organ Size/drug effects
- Phenylephrine/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/physiology
- Vasoconstriction/drug effects
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Affiliation(s)
- Anastasia Z Kalea
- Department of Food Science and Human Nutrition, College of Natural Sciences, Forestry and Agriculture, University of Maine, Orono, ME 04469, USA
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49
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Kwan HY, Huang Y, Yao X. Regulation of canonical transient receptor potential isoform 3 (TRPC3) channel by protein kinase G. Proc Natl Acad Sci U S A 2004; 101:2625-30. [PMID: 14983059 PMCID: PMC357000 DOI: 10.1073/pnas.0304471101] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Canonical transient receptor potential (TRPC) channels are Ca2+-permeable nonselective cation channels that are widely expressed in numerous cell types. Seven different members of TRPC channels have been isolated. The activity of these channels is regulated by the filling state of intracellular Ca2+ stores and/or diacylglycerol and/or Ca2+/calmodulin. However, no evidence is available as to whether TRPC channels are regulated by direct phosphorylation on the channels. In the present study, TRPC isoform 3 (TRPC3) gene was overexpressed in HEK293 cells that were stably transfected with protein kinase G (PKG). We found that the overexpressed TRPC3 mediated store-operated Ca2+ influx and that this type of Ca2+ influx was inhibited by cGMP. The inhibitory effect of cGMP was abolished by KT5823 or H8. Point mutations at two consensus PKG phosphorylation sites (T11A and S263Q) of TRPC3 channel markedly reduced the inhibitory effect of cGMP. In addition, TRPC3 proteins were purified from HEK293 cells that were transfected with either wild-type or mutant TRPC3 constructs, and in vitro PKG phosphorylation assay was carried out. It was found that wild-type TRPC3 could be directly phosphorylated by PKG in vitro and that the phosphorylation was abolished in the presence of KT5823. The phosphorylation signal was greatly reduced in mutant protein T11A or S263Q. Taken together, TRPC3 channels could be directly phosphorylated by PKG at position T11 and S263, and this phosphorylation abolished the store-operated Ca2+ influx mediated by TRPC3 channels in HEK293 cells.
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Affiliation(s)
- Hiu-Yee Kwan
- Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China
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50
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Ahmmed GU, Mehta D, Vogel S, Holinstat M, Paria BC, Tiruppathi C, Malik AB. Protein kinase Calpha phosphorylates the TRPC1 channel and regulates store-operated Ca2+ entry in endothelial cells. J Biol Chem 2004; 279:20941-9. [PMID: 15016832 DOI: 10.1074/jbc.m313975200] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The TRPC1 (transient receptor potential canonical-1) channel is a constituent of the nonselective cation channel that mediates Ca2+ entry through store-operated channels (SOCs) in human endothelial cells. We investigated the role of protein kinase Calpha (PKCalpha) phosphorylation of TRPC1 in regulating the opening of SOCs. Thrombin or thapsigargin added to the external medium activated Ca2+ entry after Ca2+ store depletion, which we monitored by changes in cellular Fura 2 fluorescence. Internal application of the metabolism-resistant analog of inositol 1,4,5-trisphosphate (IP3) activated an inward cationic current within 1 min, which we recorded using the whole cell patch clamp technique. La3+ or Gd3+ abolished the current, consistent with the known properties of SOCs. Pharmacological (Gö6976) or genetic (kinase-defective mutant) inhibition of PKCalpha markedly inhibited IP3-induced activation of the current. Thrombin or thapsigargin also activated La3+-sensitive Ca2+ entry in a PKCalpha-dependent manner. We determined the effects of a specific antibody directed against an extracellular epitope of TRPC1 to address the functional importance of TRPC1. External application of the antibody blocked thrombin- or IP3-induced Ca2+ entry. In addition, we showed that addithrombin or thapsigargin induced phosphorylation of TRPC1 within 1 min. Thrombin failed to induce TRPC1 phosphorylation in the absence of PKCalpha activation. Phosphorylation of TRPC1 and the resulting Ca2+ entry were essential for the increase in permeability induced by thrombin in confluent endothelial monolayers. These results demonstrate that PKCalpha phosphorylation of TRPC1 is an important determinant of Ca2+ entry in human endothelial cells.
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Affiliation(s)
- Gias U Ahmmed
- Department of Pharmacology, College of Medicine, University of Illinois, 835 S. Wolcott Avenue, Chicago, IL 60612, USA
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