TRP Channel-Dependent Regulation of Arterial Tone

TRP 通道依赖性动脉张力调节

• 批准号: 7754061
• 负责人: Scott Earley
• 金额: $ 36.5万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7754061
• 关键词: 1,2-diacylglycerol; Acute; Address; Agonist; Arteries; Blood Pressure; Blood Vessels; Blood flow; Calcium Signaling; Caliber; Cardiovascular system; Cell Line; Cell membrane; Cells; Cleaved cell; Coronary Arteriosclerosis; Development; Diglycerides; Disease; Down-Regulation; Electrophysiology (science); Event; Generations; Goals; Health; Human; Hypertension; Image; Inositol; Investigation; Ion Channel Protein; Length; Life; Mediating; Mediator of activation protein; Membrane; Membrane Potentials; Microcirculation; Microelectrodes; Muscle; Muscle Cells; Muscle Proteins; Outcome; Pathology; Pharmacologic Substance; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipase C; Physiological; Property; Protein Isoforms; Protein Kinase C; Proteins; Regulation; Role; Sarcoplasmic Reticulum; Second Messenger Systems; Series; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Smooth Muscle; Smooth Muscle Myocytes; Stimulus; Stroke; Techniques; Technology; Testing; Travel; Vascular Smooth Muscle; Vascular resistance; Vasoconstrictor Agents; Video Microscopy; arteriole; cerebral artery; citrate carrier; constriction; drug discovery; improved; in vivo; novel; patch clamp; phosphatidylinositol phosphate, PtdIns(4,5)P2; pressure; prevent; public health relevance; receptor; research study; response; second messenger; trafficking; vasoconstriction; voltage

DESCRIPTION (provided by applicant): The luminal diameter of muscular arteries and arterioles of the microcirculation is the principal site of control of vascular resistance. These small blood vessels are significant regulators of blood pressure and local blood flow distribution, and impaired control of their luminal diameter is a major contributor to cardiovascular-related diseases. Vascular smooth muscle cell membrane potential depolarization is central to the actions of vasoconstrictors, including intravascular pressure. Despite considerable investigation, the mechanisms underlying membrane potential depolarization remain obscure. In this proposal, we will examine the novel concept that activation of the melastatin transient receptor potential (TRP) channel TRPM4 in arterial myocytes integrates signals activated by vasoconstrictor stimuli to cause membrane potential depolarization. Evidence is provided that activation of TRPM4 channels causes membrane depolarization, Ca2+ influx via voltage-dependent Ca2+ channels, and vasoconstriction. Thus, TRPM4 appears to be an important mediator of smooth muscle cell depolarization. As such, an increase in TRPM4 activity or channel number could contribute to vascular pathologies such as hypertension, which are characterized by smooth muscle membrane potential depolarization and vasoconstriction. TRPM4 therefore presents an attractive target for drug-discovery efforts, but currently, little is known about how activity of the channel is controlled under physiological conditions. Phospholipase C (PLC), protein kinase C (PKC), and intracellular Ca2+ dynamics contribute to the control of arterial tone in vivo, and are thought to be important regulators of TRPM4. This proposal will address the central hypothesis that these factors elicit vasoconstriction, in part, by modulating the activity of TRPM4. Experiments are proposed that will use patch-clamp electrophysiology and live-cell confocal imaging experiments to elucidate how TRPM4 activity is regulated by PLC and PKC activity in vascular smooth muscle cells (Specific Aim 1), and by dynamic Ca2+ events involving IP3-mediated Ca2+ release from intracellular stores (Specific Aim 2). Specific Aim 3 will extend these studies to the level of the intact vasculature and investigate the role of PLC, PKC, and Ca2+-dependent regulation of TRPM4 in pressure and agonist-induced vasoconstriction. These experiments will utilize intact cerebral arteries for intracellular microelectrode recordings of smooth muscle membrane potential confocal Ca2+ imaging, and simultaneous contractile and Ca2+ imaging studies. Additional experiments will employ siRNA technology to suppress TRPM4 expression in intact blood vessels. The outcome of these experiments will significantly enhance our understanding of the role of TRPM4 in blood pressure and blood flow regulation, findings that will contribute to the development of novel therapies for the treatment of cardiovascular-related diseases. PUBLIC HEALTH RELEVANCE: Experiments described in this proposal will examine how TRPM4, an ion channel protein present in smooth muscle cells that line the walls of blood vessels, controls the diameter of small arteries and arterioles. This is important because these small blood vessels regulate blood flow and pressure, and impaired control of their diameter contributes to cardiovascular-related disease, such as hypertension, stroke, and coronary artery disease. The ultimate goal of this project is to improve human health by stimulating the development of new pharmaceuticals that act through TRPM4 to control and prevent cardiovascular-related diseases.

描述（由申请人提供）：微循环的肌肉动脉和小动脉的腔直径是控制血管抗性的主要部位。这些小血管是血压和局部血流分布的重要调节剂，对其管腔直径的控制受损是导致心血管相关疾病的主要因素。血管平滑肌细胞膜电位去极化对于血管收缩剂的作用（包括血管内压力）至关重要。尽管进行了大量研究，但膜电势去极化的机制仍然晦涩。在该提案中，我们将研究一种新的概念，即在动脉心肌细胞中激活绿色脂肪素瞬态受体电位（TRP）通道TRPM4会整合由血管收敛刺激激活的信号，从而导致膜潜在的去极化。有证据表明，TRPM4通道的激活会导致膜去极化，Ca2+通过电压依赖性Ca2+通道和血管收缩。因此，TRPM4似乎是平滑肌细胞去极化的重要介质。因此，TRPM4活性或通道数的增加可能导致血管病理（例如高血压），其特征是平滑肌膜潜在的去极化和血管收缩。因此，TRPM4为药物发现努力提供了一个有吸引力的目标，但目前，人们对在生理条件下如何控制通道的活动知之甚少。磷脂酶C（PLC），蛋白激酶C（PKC）和细胞内Ca2+动力学有助于控制体内动脉张力，被认为是TRPM4的重要调节剂。该提案将解决以下中心假设：这些因素部分通过调节TRPM4的活性引起血管收缩。提出了实验，该实验将使用Patch-Clamp电生理学和活细胞共聚焦成像实验来阐明在血管平滑肌细胞中如何通过PLC和PKC活性调节TRPM4活性（特定的AIM AIM 1），以及涉及IP3介导的CA2+ CA2+释放的动态CA2+事件（动态CA2+事件）。具体的目标3将将这些研究扩展到完整的脉管系统水平，并研究PLC，PKC和Ca2+依赖性TRPM4在压力和激动剂引起的血管收缩中的作用。这些实验将利用完整的脑动脉来进行平滑肌肉膜电势共焦CA2+成像以及同时收缩和CA2+成像研究的细胞内微电极记录。其他实验将采用siRNA技术来抑制完整血管中的TRPM4表达。这些实验的结果将显着增强我们对TRPM4在血压和血流调节中的作用的理解，这些发现将有助于开发新的疗法，以治疗心血管相关疾病。公共卫生相关性：本提案中描述的实验将检查TRPM4是如何在血管壁上排列的平滑肌细胞中存在的离子通道蛋白，控制小动脉和动脉的直径。这很重要，因为这些小血管调节血流和压力，并且对其直径的控制受损会导致与心血管相关疾病，例如高血压，中风和冠状动脉疾病。该项目的最终目的是通过刺激通过TRPM4起作用的新药物的开发来改善人类健康，以控制和防止心血管相关疾病。