Hemodynamic forces regulate BMPs in coronary arteries

描述(由申请人提供)：最近的研究表明，冠状动脉疾病(CAD)的发展与骨形态发生蛋白(BMPs)和肿瘤坏死因子(TNF)的表达增强有关。肿瘤坏死因子(TNF)和骨形态发生蛋白2/4(BMP2/4)是促炎症细胞因子，可诱导内皮细胞活化，促进单核细胞黏附。尽管BMP2/4和肿瘤坏死因子具有重要的病理生理意义，但调控这些细胞因子在冠状动脉中表达的机制尚不清楚。我发现，在主动脉结扎的大鼠中，暴露在高压下的冠状动脉和前肢动脉表现出更高的氧化应激和促炎症细胞因子的上调，而相同动物的动脉(位于缩窄处下游)在正常压力下表现出正常的氧气产生和表型。在培养的内皮细胞中，氧化应激和振荡剪切力可促进BMPs的转录。基于这些观察和广泛的初步结果，我认为冠状动脉BMP和肿瘤坏死因子(TNF)的表达受易发生动脉粥样硬化的血流动力学力量的调节。该项目的总体目标是验证一种假设，即易发生动脉粥样硬化的血流动力增加ROS的生成，并激活冠状动脉内皮细胞和/或平滑肌细胞中氧化还原敏感的转录因子，从而上调BMPs和TNF，从而诱导内皮细胞激活，上调细胞黏附分子，并增强单核细胞与内皮的黏附。为了研究不同压力和剪应力条件的影响，并分析其潜在的分子机制，我们将使用体内模型(主动脉缩窄诱导的冠状动脉高血压)和一种新的血管培养系统。目的#1：确定易发生动脉粥样硬化的血流动力是否调节冠状动脉中BMPs和肿瘤坏死因子的表达。目的#2：阐明动脉粥样硬化易致血流动力、O2.-、H_2O_2和/或ONOO-水平升高与血管内皮细胞和血管内皮细胞表达促炎细胞因子之间的关系。目的#3：探讨动脉粥样硬化易致血流动力是否激活冠状动脉中的核因子-B、AP-1和/或PARs，以及这些转录因子是否调节BMPs和肿瘤坏死因子的表达。目的#4：阐明骨形态发生蛋白诱导内皮细胞活化促进单核细胞黏附在冠状动脉中的机制。识别这些新的细胞和分子机制参与冠状动脉早期促动脉粥样硬化的改变，最终可能导致特定的治疗干预措施，以防止CAD的发展。

DESCRIPTION (provided by applicant): Recent studies suggest that development of coronary artery disease (CAD) is associated with an enhanced expression of bone morphogenic proteins (BMPs) and TNF(. TNF( and BMP2/4 are pro-inflammatory cytokines that induce endothelial activation and promote monocyte adhesion. Despite the pathophysiological importance of BMP2/4 and TNF(, the mechanisms that regulate the expression of these cytokines in coronary arteries are completely unknown. I found that in aortic banded rats coronary arteries and forelimb arteries which are exposed to high pressure exhibit an increased oxidative stress and an up-regulation of pro-inflammatory cytokines, whereas arteries (located downstream from the coarctation) of the same animals which are exposed to normal pressure exhibit normal O2.- production and phenotype. In cultured endothelial cells oxidative stress and oscillatory shear stress were shown to enhance the transcription of BMPs. On the basis of these observations and extensive preliminary results I propose that coronary arterial BMP and TNF( expression is regulated by athero-prone hemodynamic forces. The overall goal of the proposed project is to test the hypothesis that athero-prone hemodynamic forces increase ROS generation and activate redox-sensitive transcription factors in endothelial and/or smooth muscle cells of coronary arteries with the consequent up-regulation of BMPs and TNF(, which induce endothelial activation, up-regulating cellular adhesion molecules and enhancing monocyte adhesion to the endothelium. To investigate the effects of different pressure and shear stress conditions and dissect the underlying molecular mechanisms both an in vivo model (aortic constriction-induced coronary arterial hypertension) and a novel vessel culture system will be used. Aim #1: To determine whether athero-prone hemodynamic forces regulate expression of BMPs and TNF( in coronary arteries. Aim #2: To elucidate the link between athero-prone hemodynamic forces, increased levels of O2.-, H2O2 and/or ONOO- and expression of pro-inflammatory cytokines in endothelial and smooth muscle cells. Aim #3: To determine whether athero-prone hemodynamic forces activate NF-(B, AP-1 and/or PARS in coronary arteries and whether these transcription factors regulate expression of BMPs and TNF(. Aim #4: To elucidate the mechanisms by which BMPs elicit endothelial activation promoting monocyte adhesion in coronary arteries. The identification of these novel cellular and molecular mechanisms involved in early pro-atherogenic alterations in coronary arteries may ultimately lead to specific therapeutic interventions preventing the development of CAD.