NO-induced vascular smooth muscle cell motility

NO诱导血管平滑肌细胞运动

• 批准号: 7033525
• 负责人: AVIV HASSID
• 金额: $ 36.5万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7033525
• 关键词: angiotensin II; angiotensin receptor; aorta; cardiovascular injury; cell motility; cell proliferation; enzyme activity; hyperinsulinism; insulin; laboratory rat; metabolic syndrome; nitric oxide; nitric oxide synthase; phosphatidylinositol 3 kinase; phosphoproteins; platelet derived growth factor; protein tyrosine phosphatase; tissue /cell culture; vascular smooth muscle; vasomotion

DESCRIPTION (provided by applicant): Nitric oxide (NO) is generally considered to play a protective role in blood vessels. However, others and we have obtained evidence that this may not always be the case but the mechanisms underlying diverse responses to NO are not known. The purpose of this proposal is to test an exciting new hypothesis on the capacity of chronically elevated insulin levels to switch the role of nitric oxide from protective to deleterious substance in blood vessels. We have found that the inhibitory effects of NO on both motility and proliferation are abrogated in vascular smooth muscle cells chronically treated with insulin. These findings support a new hypothesis on the role of insulin as a switcher of vascular smooth muscle cell phenotypic responses to NO. Our preliminary results indicate that the motility-stimulatory effect of NO, uncovered by chronic insulin treatment of cultured rat aortic smooth muscle cells, is associated with increased PI 3 kinase activity and requires the functional availability of angiotensin II, of the adapter protein Gab1 and the protein tyrosine phosphatase SHP2. Studies by others have found that Gab1 can be recruited to the plasma membrane via increased PIPS levels. However, the mechanistic linkage of chronic insulin treatment to Gab1 and SHP2 function has not been defined. Moreover, experiments to determine whether similar mechanisms may be applicable to abrogation of the antiproliferative effect of NO by chronic insulin treatment have not been performed. Finally, the pathophysiological significance of our results is unknown. We propose to implement the following specific aims: Aim 1: To determine whether increased angiotensin II function is necessary and/or sufficient to account for the effect of insulin on PI3K activity and NO-induced cell motility. Aim 2: To determine whether chronic insulin treatment recruits Gab1 to the cell membrane and whether insulin- independent recruitment of Gab1 or SHP2 to the cell membrane can mimic the motility-stimulatory effect of NO uncovered by chronic insulin treatment. Aim 3: To uncover mechanisms that describe how hyperinsulinemia attenuates the effect of NO as inhibitor of PDGF-induced DNA synthesis, in cultured rat aortic smooth muscle cells. Aim 4: To determine whether expression of inducible nitric oxide synthase in vascular injury enhances neointima formation in hyperinsulinemic mice, but has the opposite effect in normoinsulinemic mice or in hyperinsulinemic mice treated with an AT1 receptor antagonist.

描述（由申请人提供）：一氧化氮（NO）通常被认为在血管中起保护作用。然而，其他人和我们已经获得的证据表明，情况可能并非总是如此，但对NO的不同反应背后的机制尚不清楚。这项提议的目的是测试一个令人兴奋的新假设，即长期升高的胰岛素水平能够将一氧化氮的作用从血管中的保护性物质转变为有害物质。我们发现，一氧化氮对血管平滑肌细胞运动和增殖的抑制作用在长期胰岛素治疗的血管平滑肌细胞被取消。这些发现支持了胰岛素作为血管平滑肌细胞对NO表型反应开关的新假设。我们的初步结果表明，通过对培养的大鼠主动脉平滑肌细胞进行慢性胰岛素治疗，发现NO的运动刺激作用与PI 3激酶活性增加有关，并且需要血管紧张素II、转换蛋白Gab1和酪氨酸磷酸酶SHP2的功能可用性。其他人的研究发现，Gab1可以通过增加的PIPS水平被募集到质膜上。然而，慢性胰岛素治疗与Gab1和SHP2功能的机制联系尚未明确。此外，还没有实验来确定是否类似的机制可能适用于通过慢性胰岛素治疗来消除NO的抗增殖作用。最后，我们的结果的病理生理意义是未知的。我们建议实现以下具体目标：目的1：确定血管紧张素II功能的增加是否必要和/或充分解释胰岛素对PI3K活性和no诱导的细胞运动的影响。目的2：确定慢性胰岛素治疗是否将Gab1招募到细胞膜上，以及Gab1或SHP2的胰岛素非依赖性招募到细胞膜上是否可以模拟慢性胰岛素治疗所揭示的NO的运动刺激作用。目的3：揭示在培养的大鼠主动脉平滑肌细胞中，高胰岛素水平如何减弱NO作为pdgf诱导的DNA合成抑制剂的作用的机制。目的4：确定血管损伤中诱导型一氧化氮合酶的表达是否促进了高胰岛素血症小鼠的新内膜形成，但在正常胰岛素血症小鼠或接受AT1受体拮抗剂治疗的高胰岛素血症小鼠中具有相反的作用。