Properties of Clca Channels in Vascular Myocytes

血管肌细胞 Clca 通道的特性

基本信息

批准号：
7245897
负责人：
Normand Leblanc
金额：
$ 30.93万
依托单位：
UNIVERSITY OF NEVADA RENO
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-07-01 至 2010-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7245897
关键词：
Anions Appendix Architecture Arteries Behavior Biochemical Biochemistry Blood Vessels Calcineurin Calmodulin Candidate Disease Gene Cell Line Cell Membrane Permeability Cell Volumes Cell membrane Chloride Ion Class Computer Simulation Condition Coronary Cytoplasm Data Dependence Development Disease Equilibrium Etiology Follow-Up Studies Future Gene Family Goals Grant Health Human Image Imaging technology Journals Kinetics Knowledge Lung Maintenance Mammalian Cell Measures Mechanics Membrane Membrane Potentials Messenger RNA Modeling Molecular Molecular Biology Techniques Muscle Cells Nature Oryctolagus cuniculus Permeability Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiological Play Property Protein Dephosphorylation Protein Isoforms Protein Phosphatase 2A Regulatory Subunit PR53 Protein Serine/Threonine Phosphatase Pulmonary Circulation Pulmonary Hypertension Pulmonary artery structure Pump Recommendation Regulation Relative (related person)Reporting Research Research Personnel Resistance Rest Role Side Smooth Muscle Smooth Muscle Myocytes Specificity Swelling System Testing Thinking Transcript Vascular Smooth Muscle Vasoconstrictor Agents Veins calcineurin phosphatase calmodulin-dependent protein kinase II cell type member novel patch clamp programs research study size symporter vascular bed voltage

项目摘要

DESCRIPTION (provided by applicant): The long term objective of the applicant's research program is to unravel the ionic mechanisms that are involved in the control of electrical and mechanical activities of the smooth muscle cells of large conduit and resistance-sized vessels in health and disease. In smooth muscle cells, chloride ions (Cl-) are not passively distributed across the cell membrane. It is thought that this anion is actively accumulated in the cytoplasm by various anion transporters. Such a high internal level of Cl- (~ 40 mM) results in a predicted equilibrium for Cl- (ECl) that is more positive (-25 mV) than the resting membrane potential (RMP) of vascular smooth muscle cells (~ -40 to -60 mV). Because of this deviation between ECl and RMP, any increase in permeability to Cl- would result in passive Cl" efflux, membrane depolarization and increased vascular tone. In spite of our knowledge about high resting membrane permeability to Cl- in smooth muscle cells, the nature of this basal anion conductance still remains undefined. This proposal is focused on elucidating the mechanisms involved in the regulation by phosphorylation mechanisms involving calmodulin-dependent kinase II (CaMKII) and serine/threonine phosphatases (Calcineurin and PP2A) of a Cl- channel activated by intracellular Ca2+ (ClCa ) in pulmonary arterial smooth muscle cells, and how this might impact on the electrical and vasoactive properties of the pulmonary circulation. 4 Specific Aims are proposed in this grant: (1) determine the effect of general phosphorylation status on the biophysical properties of Clca channels in rabbit pulmonary artery smooth muscle cells; (2) determine the relative role of CaMKII and serine/threonine phosphatases in the regulation of ClCa channels in rabbit pulmonary artery smooth muscle cells; (3) determine the physiological impact of phosphatase regulation of ClCa channels on membrane potential, Ca2+ transients and tone in pulmonary arterial smooth muscle cells and intact pulmonary arteries; and (4) clone and express 3 candidate genes encoding Ca2+-activated Cl- channels in rabbit pulmonary artery and evaluate their physiological relevance to the native channels. A strong team of collaborating investigators will use a wide array of electrophysiological, biochemical and molecular biology techniques, as well as confocal imaging technology and computer simulations to accomplish the above goals. The etiology of pulmonary hypertension (PH) in humans is still poorly understood although it is becoming increasingly clear that defective ionic mechanisms may play a role in this disease. Because of their potential importance as an excitatory mechanism in pulmonary arteries, impaired regulation and/or expression of Clca channels could potentially participate in PH. The proposed studies will not only advance our knowledge about their basic properties, but should also pave the way for the development of future therapies to treat PH.

描述（由申请人提供）：申请人研究计划的长期目标是揭示参与控制健康和疾病中大型导管和阻力大小血管的平滑肌细胞的电和机械活动的离子机制。在平滑肌细胞中，氯离子 (Cl-) 并不是被动分布在细胞膜上。据认为，这种阴离子通过各种阴离子转运蛋白在细胞质中积极积累。如此高的内部 Cl- 水平 (~ 40 mM) 导致 Cl- (ECl) 的预测平衡比血管平滑肌细胞的静息膜电位 (RMP) (~ -40 mV) 更正 (-25 mV)至-60毫伏）。由于 ECl 和 RMP 之间的这种偏差，任何对 Cl- 通透性的增加都会导致 Cl- 被动外流、膜去极化和血管张力增加。尽管我们知道平滑肌细胞对 Cl- 的静息膜通透性较高，但这种基础阴离子电导的性质仍未明确，该提案的重点是阐明涉及钙调蛋白依赖性激酶 II (CaMKII) 和丝氨酸/苏氨酸磷酸酶的磷酸化机制的调节机制。肺动脉平滑肌细胞中细胞内 Ca2+ (ClCa) 激活的 Cl- 通道（钙调神经磷酸酶和 PP2A），以及这可能如何影响肺循环的电和血管活性特性，本次资助提出了 4 个具体目标：（ 1)确定一般磷酸化状态对兔肺动脉平滑肌细胞Clca通道生物物理特性的影响(2)确定CaMKII和丝氨酸/苏氨酸的相对作用；磷酸酶对兔肺动脉平滑肌细胞 ClCa 通道的调节作用(3)确定磷酸酶调节ClCa通道对肺动脉平滑肌细胞和完整肺动脉膜电位、Ca2+瞬变和张力的生理影响； (4)在兔肺动脉中克隆并表达编码Ca2+激活的Cl-通道的3个候选基因，并评估它们与天然通道的生理相关性。强大的合作研究团队将使用广泛的电生理学、生化和分子生物学技术，以及共焦成像技术和计算机模拟来实现上述目标。尽管越来越清楚的是，有缺陷的离子机制可能在这种疾病中发挥作用，但对人类肺动脉高压 (PH) 的病因仍知之甚少。由于其作为肺动脉兴奋机制的潜在重要性，Clca 通道的调节和/或表达受损可能参与 PH。拟议的研究不仅将增进我们对其基本特性的了解，而且还应该为未来治疗 PH 的疗法的开发铺平道路。