FLUID SHEAR STRESS SIGNAL TRANSDUCTION IN ENDOTHELIUM

描述：本项目的主要目标是表征 血流激活内皮细胞内信号转导机制 细胞（EC），提供保护免受动脉粥样硬化。的概念 炎症在炎症的发病机制和进展中起着关键作用， 动脉粥样硬化最近得到了很多支持。的主要假设 该建议是稳定的层流剪切应力通过以下方式限制动脉粥样硬化： 抑制促动脉粥样硬化的基因表达程序， 炎性细胞因子因为转录因子的活性 负责基因表达的蛋白质磷酸化控制， 实验室专注于蛋白激酶。我们已经阐明了机制， 有丝分裂原活化蛋白激酶（MAPK）的哪些成员被 血流和肿瘤坏死因子（TNF）。MAPK磷酸化激活 诱导促炎和抗炎基因表达的转录因子 分子。特别地，c-Jun N-末端激酶（JNK）被许多细胞因子激活。 炎性细胞因子（例如，TNF和IL-1）。我们建议， 流动调节细胞因子激活LINK的机制将提供 深入了解由流动引起的动脉粥样硬化保护机制。具体 要研究的假设是，流量调节几种途径 （细胞凋亡信号调节激酶（ASK 1），含Src同源性-2结构域 磷酸酶（SHP 2）、细胞外信号调节激酶（ERK 1/2和ERK 5或ERK 6）、 BMK 1）和JNK磷酸酶）抑制JNK活性。令人兴奋的初步数据 表明EC预暴露于稳定层流可防止TNF介导 JNK激活，与ASK！和 SHP2.这种抑制作用主要不是由于一氧化氮（NO）的作用， 这一机制尚未得到很好的探索。为了证明我们的假设三 提出了具体目标。1)识别信号转导机制 负责JNK活性的流动依赖性抑制，集中于BMK 1， ERK1/2，ASK！，SHP 2和LINK磷酸酶。2)确定影响的 心血管危险因素（振荡流和氧化应激） 流动介导的JNK活性抑制。3)描述...的效果 改变JNK活化（通过腺病毒和反义寡核苷酸 转染）对离体灌注的兔主动脉对TNF的反应的影响。 这些研究应该提供对流动机制的深入了解， 产生动脉粥样硬化保护信号，促进新的 限制动脉粥样硬化的治疗方法。

DESCRIPTION: The primary goal of this project is to characterize the intracellular signal transduction mechanisms activated by flow in endothelial cells (EC) that confer protection from atherosclerosis. The concept that inflammation plays a key role in the pathogenesis and progression of atherosclerosis has recently received much support. The major hypothesis of this proposal is that steady laminar shear stress limits atherosclerosis by inhibiting the pro-atherogenic program of gene expression induced by inflammatory cytokines. Because the activity of transcription factors responsible for gene expression is controlled by protein phosphorylation our laboratory has focused on protein kinases. We have elucidated mechanisms by which members of the mitogen activated protein kinases (MAPK) are activated by flow and tumor necrosis factor (TNF). MAPK phosphorylate and activate transcription factors that induce expression of both pro- and anti-inflammatory molecules. In particular, c-Jun N-terminal kinase (JNK) is activated by many inflammatory cytokines (e.g., TNF and IL-1). We propose that understanding the mechanisms by which flow regulates LINK activation by cytokines will provide insight into the atheroprotective mechanisms induced by flow. The specific hypothesis to be investigated is that flow regulates several pathways (apoptosis signal regulated kinase (ASK1), Src homology-2 domain containing phosphatase (SHP2), extracellular signal regulated kinases (ERK1/2 and ERK5 or BMK1), and JNK phosphatases) to inhibit JNK activity. Exciting preliminary data indicate that pre-exposure of EC to steady laminar flow prevents TNF-mediated JNK activation, in association with decreases in TNF activation of ASK! and SHP2. This inhibition is not due primarily to effects of nitric oxide (NO), a mechanism that has not been well explored. To prove our hypotheses three specific aims are proposed. 1) Identify signal transduction mechanisms responsible for flow-dependent suppression of JNK activity, focusing on BMK1, ERK1/2, ASK!, SHP2 and LINK phosphatases. 2) Determine the effect of cardiovascular risk factors (oscillatory flow and oxidative stress) on flow-mediated suppression of JNK activity. 3) Characterize the effect of altering JNK activation (by adenoviral and antisense oligonucleotide transfection) on the response of the ex vivo perfused rabbit aorta to TNF. These studies should provide insight into the mechanisms by which flow generates an atheroprotective signal and facilitate development of new therapeutic approaches to limit atherosclerosis.