FLUID SHEAR STRESS SIGNAL TRANSDUCTION IN ENDOTHELIUM

描述：这个项目的主要目标是描述 内皮细胞内流激活的细胞内信号转导机制 保护动脉粥样硬化的细胞(EC)。这个概念就是 炎症在肿瘤的发生和发展中起着关键作用。 动脉粥样硬化最近得到了很多支持。的主要假说 这一建议是稳定的层流剪应力通过限制动脉粥样硬化 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 负责基因表达的是由蛋白质磷酸化OUR控制的 实验室一直专注于蛋白激酶的研究。我们已经通过以下方式阐明了机制 丝裂原活化蛋白激酶(MAPK)的哪些成员被激活 Flow和肿瘤坏死因子(TNF)。MAPK磷酸化和激活 诱导促炎和抗炎基因表达的转录因子 分子。特别是，c-jun氨基末端激酶(JNK)被许多人激活 炎性细胞因子(如肿瘤坏死因子和白介素1)。我们建议理解 Flow通过细胞因子调节链接激活的机制将提供 洞察血流诱导的动脉粥样硬化保护机制。具体的 需要研究的假设是，流调节几条路径。 (凋亡信号调节激酶(ASK1)，Src同源2结构域，包含 磷酸酶(SHP2)、细胞外信号调节蛋白(ERK1/2和ERK5或 BMK1)和JNK磷酸酶)来抑制JNK活性。令人振奋的初步数据 表明EC预先暴露在稳定的层流中可阻止肿瘤坏死因子的介导 JNK活化与ASK！的肿瘤坏死因子活性降低有关。和 Shp2.这种抑制主要不是由于一氧化氮(NO)的影响， 这一机制尚未得到很好的探索。为了证明我们的假设三 提出了具体的目标。1)识别信号转导机制 负责JNK活性的流动依赖抑制，重点是BMK1， ERK1/2、ASK！、SHP2和连接磷酸酶。2)确定 心血管危险因素(振荡血流和氧化应激) 流式细胞介导的JNK活性抑制。3)描述 改变JNK活性(用腺病毒和反义寡核苷酸 体外灌流的兔主动脉对肿瘤坏死因子的反应。 这些研究应该提供对流动机制的洞察 产生动脉粥样硬化保护信号，并促进新的 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.