Regulation of Vascular Tone and Ca Channels by Integrins

整合素对血管张力和 Ca 通道的调节

• 批准号: 7651967
• 负责人: Michael John Davis
• 金额: $ 37.38万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-04 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7651967
• 关键词: Actinin; Adhesions; Affect; Agonist; Atherosclerosis; Blood Pressure; Blood Vessels; Blood flow; Calcium; Calcium-Activated Potassium Channel; Caliber; Cell membrane; Cells; Chemosensitization; Chronic; Collagen; Contracts; Diabetes Mellitus; Digestion; Dilatation - action; Disease; Extracellular Matrix; Extracellular Matrix Degradation; Extracellular Matrix Proteins; Fibronectins; Focal Adhesions; Infiltration; Inflammation; Inflammatory; Injury; Integrins; Ion Channel; Ion Channel Protein; Mechanics; Mediating; Metabolic; Methods; Mus; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Physiological; Play; Potassium; Process; Property; Protein Tyrosine Phosphatase; Proteins; Rattus; Regulation; Reperfusion Injury; Resistance; Role; Site; Skeletal Muscle; Smooth Muscle; Smooth Muscle Myocytes; Stretching; Talin; Testing; Tissues; Transgenic Animals; Transgenic Mice; Vascular Smooth Muscle; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents; Work; arteriole; constriction; diabetic; human BCAR1 protein; integrin-linked kinase; interest; large-conductance calcium-activated potassium channels; mouse model; osteopontin; patch clamp; paxillin; pressure; protein expression; public health relevance; receptor; relating to nervous system; response; transmission process; voltage

DESCRIPTION (provided by applicant): Interactions between vascular integrins and extracellular matrix (ECM) components of the blood vessel wall are important determinants of arteriolar tone and blood flow control. Importantly, arteriolar responsiveness to pressure and to agonists is compromised in diabetes, atherosclerosis, and other inflammatory / injury conditions in which the composition of the vascular wall is altered. In this application, we focus on two aspects of vascular function in which ECM-integrin interactions acutely regulate vascular tone: 1) mechanotransduction of intravascular pressure through the voltage-gated, L-type Ca2+ channel (CaL), which is the primary Ca2+ entry pathway in VSM, and 2) the effects of biologically active matricryptins (i.e., proteolytic fragments of ECM proteins with vasoactive properties). Our interest centers on how these regulatory mechanisms converge on vascular smooth muscle (VSM) ion channels to regulate intracellular Ca2+ and control constriction/dilation. Our previous studies show that the regulation of CaL current is a key mechanism whereby at least two VSM integrins, 1521 and 1v23, control myogenic vascular tone. The central hypothesis of this proposal is that 1521 integrin plays a critical role in mediating the transduction of physiological stretch to VSM CaL channels to enhance myogenic tone, while 1v23 integrin functions as a matricryptin receptor to inhibit myogenic tone and initiate vasodilation in response to vessel wall injury. The hypothesis will be tested using patch-clamp methods to record CaL and BK (large-conductance calcium-activated K+ channel) currents in single rat or mouse VSM cells and diameter responses of isolated arterioles in conjunction with adenoviral methods and transgenic animals to manipulate the expression of selected proteins in arteriolar smooth muscle. There are two aims. Aim A will determine how longitudinal cell stretch is transduced through integrins to potentiate VSM CaL channels and myogenic tone. We predict that: 1) 1521 integrin but not 1v23 integrin transduces mechanical force to regulate VSM CaL channels, 2) the intrinsic stretch-sensitivity of CaL is unimportant compared to integrin-mediated force transduction to CaL, and 3) talin-1, paxillin, 1-actinin and p130Cas are critical focal adhesion proteins required for force transmission through integrins to CaL channels in VSM. Aim B will determine how 1v23 integrin functions as a matricryptin receptor to inhibit myogenic tone through VSM CaL and BK channels. We predict that: 1) fibronectin, osteopontin and collagen contain matricryptic sites that induce arteriolar dilatation; 2) matricryptins act by inhibition of CaL channels and/or activation of BK channels; 3) matricryptins inhibit CaL through PKG phosphorylation of an inhibitory site on CaL or activation of a tyrosine phosphatase to inhibit Src-induced CaL phosphorylation; and 4) matricryptins will not evoke dilatation in arterioles from 23 integrin-/- mice or modulate BK CaL channels in 23 integrin-/- VSM cells. These studies are important for understanding the mechanisms by which normal blood vessel function is regulated by ECM-integrin interactions and how these processes become impaired in diseases such as atherosclerosis and diabetes, where substantial changes in vessel wall composition and reactivity occur. PUBLIC HEALTH RELEVANCE: Blood vessels normally respond to physical forces, like blood pressure, to control and distribute blood flow to every tissue. One focus of this proposal is to determine how changes in pressure are detected by ion channels in the walls of blood vessels. Ion channels are proteins that control the flux of potassium and calcium across the cell membranes and their activity strongly influences the control of vessel diameter and blood flow. A second focus of the proposal relates to the fact that the protein composition of the vascular wall changes as the wall is remodeled in chronic inflammatory diseases such as diabetes and atherosclerosis. Part of the disease process involves breakdown of the existing proteins that hold the vessel wall together as well as infiltration of new proteins not normally found in the wall. We will determine how these proteins are modified by the same processes as found in the diseases states and then test the effects they have on vascular ion channels and blood vessel function.

描述(申请人提供)：血管整合素和血管壁的细胞外基质(ECM)成分之间的相互作用是微动脉张力和血流控制的重要决定因素。重要的是，在糖尿病、动脉粥样硬化和其他炎症/损伤情况下，小动脉对压力和激动剂的反应性会受到损害，在这些情况下，血管壁的组成会发生变化。在这一应用中，我们重点研究了细胞外基质与整合素相互作用对血管紧张性的两个方面的影响：1)通过电压门控型L型钙通道(CAL)进行的血管内压机械转导，这是血管平滑肌中主要的钙离子进入途径；2)生物活性的Matriritins(即具有血管活性的细胞外基质蛋白的蛋白分解片段)的作用。我们的兴趣集中在这些调节机制如何汇聚到血管平滑肌(VSM)离子通道上，以调节细胞内钙离子和控制收缩/扩张。我们以前的研究表明，钙电流的调节是至少两个VSM整合素1521和1v23控制肌源性血管张力的关键机制。这一假设的核心假设是，1521整合素在介导生理性伸展到VSM Cal通道以增强肌源性张力的转导中起关键作用，而1v23整合素作为基质受体抑制肌源性张力，并在响应血管壁损伤时启动血管扩张。这一假设将通过膜片钳方法记录单个大鼠或小鼠VSM细胞的Cal和BK(大电导钙激活K+通道)电流以及分离的小动脉的直径反应，并结合腺病毒方法和转基因动物来操纵小动脉平滑肌中选定蛋白的表达。有两个目标。目的A将确定纵向细胞拉伸是如何通过整合素转导来增强VSM钙通道和肌源性张力的。我们预测：1)1521整合素而不是1v23整合素转导机械力来调节VSM Cal通道；2)与整合素介导的力传递相比，Cal固有的拉伸敏感性并不重要；3)talin-1、paxlin、1-Actinin和p130Cas是VSM中通过整合素向Cal通道传递力所必需的关键焦点黏附蛋白。目的B研究1v23整合素是如何通过VSM、Cal和BK通道作为一种基质破碎素受体抑制肌源性张力的。我们预测：1)纤维粘连蛋白、骨桥蛋白和胶原蛋白含有诱导小动脉扩张的基质位点；2)matriritins通过抑制Cal通道和/或激活BK通道发挥作用；3)matriritins通过激活Cal上的抑制位点PKG磷酸化或激活酪氨酸磷酸酶来抑制Src诱导的Cal磷酸化；以及4)matcretins不会引起23个整合素/-VSM细胞的小动脉扩张，也不会调节23个整合素/VSM细胞的BK钙通道。这些研究对于了解ECM-整合素相互作用调节正常血管功能的机制以及这些过程在动脉粥样硬化和糖尿病等疾病中如何受损非常重要，这些疾病的血管壁成分和反应性会发生实质性变化。与公共健康相关：血管通常会对血压等物理力量做出反应，以控制并将血液流动分配到每个组织。这项提议的一个重点是确定血管壁上的离子通道如何检测到压力的变化。离子通道是一种控制钾和钙跨细胞膜流动的蛋白质，它们的活动强烈影响血管直径和血流的控制。该提案的第二个重点涉及这样一个事实，即在糖尿病和动脉粥样硬化等慢性炎症性疾病中，随着血管壁的重塑，血管壁的蛋白质成分也会发生变化。疾病过程的一部分涉及将管壁结合在一起的现有蛋白质的分解，以及正常情况下在管壁中找不到的新蛋白质的渗透。我们将确定这些蛋白质是如何通过与疾病状态相同的过程进行修饰的，然后测试它们对血管离子通道和血管功能的影响。