Hemodynamics: Heterogeneous Endothelial Gene Expression

内皮细胞被认为是影响血管生理学和病理学的机械转导界面。人们很早就认识到动脉粥样硬化在与体内复杂的血流紊乱相关的区域的普遍存在，但对这些部位的易感因素和加重优先动脉粥样硬化的因素知之甚少。我们认为血流动力通过调节动脉粥样硬化部位的内皮细胞的局部表型来决定动脉粥样硬化的易感性。利用基因芯片对正常成年猪主动脉进行的初步研究表明，不同区域的内皮基因表达存在差异 容易发生动脉粥样硬化病变(血流受扰)和那些通常不受影响的区域。项目5将解决这一假设，即在病变易感部位，内皮细胞表型处于平衡状态，通过表达促炎基因而准备发展为动脉粥样硬化，但受到抗氧化机制和其他防止动脉粥样硬化开始/早期发展的基因上调的保护。暴露于一个或多个危险因素(血流动力学之外)被认为是导致血管病理发展的失衡所必需的。在与马里兰州FDA Laurel的设备和放射健康动物中心的合作下，我们将进行第一个多基因 明确血流动力学部位的在体血管内皮细胞表达研究。将确定正常成年猪动脉的局部内皮表型，并将确定重要危险因素高胆固醇血症、性别和激素操作对动脉粥样硬化启动区域的影响。血流动力学在局部易感性中的关键作用将通过在颈总动脉产生血流扰动来测试，颈总动脉通常暴露在未受扰动的层流中，并且对动脉粥样硬化具有抵抗力；我们认为这种干预将导致易感表型。 将在体外测量血流动力对抗氧化、凝血、炎症和其他基因分类的影响，并将分析猪内皮细胞在振荡和单向流动中的转录图谱。使用小干扰RNA，将产生特定的基因‘敲击’(基因沉默)，以确定对体外血流动力学反应的影响，包括通过后续蛋白质和蛋白质组学研究的微阵列分析评估的表型扰动。

The endothelium is well recognized as a mechanotranduction interface influencing vessel physiology and pathology. The prevalence of atherogenesis in regions associated with complex disturbed flows in vivo has long been recognized yet the factors that predispose such sites and potentiate preferential atherosclerosis there are poorly understood. We propose that hemodynamic forces determine the susceptibility to atherosclerosis by regulation of the regional phenotype of endothelium at such sites. Preliminary profiling studies in the normal adult porcine aorta using microarray have shown differences in endothelial gene expression between areas prone to develop atherosclerotic lesions (disturbed flow) and those areas that are typically spared. Project 5 will address the hypothesis that at lesion-susceptible locations, the endothelial phenotype is in an equilibrium state that is primed to develop atherosclerosis by expression of pro-inflammatory genes but is protected by the up-regulation of anti-oxidant mechanisms and other genes that prevent the initiation/early development of atherosclerosis. Exposure to one or more risk factors (additional to hemodynamics) is proposed to be necessary for imbalances that lead to the development of vascular pathology. In a collaboration with the Center for Devices and Radiological Health animal facility at the FDA Laurel, MD, we will conduct the first multi-gene expresssion studies of endothelium in vivo in defined hemodynamic locations. Regional endothelial phenotypes will be defined in normal adult porcine arteries, and the effects of the important risk factors hypercholesterolemia, gender, and hormonal manipulations upon atherosclerosis-primed regions will be determined. The critical role of hemodynamics in regional susceptibility will be tested by creating flow disturbances in the common carotid artery, a location that is normally exposed to undisturbed laminar flow and which is resistant to atherogenesis; we propose that a susceptible phenotype will result from such intervention. The effects of hemodynamic forces upon anti-oxidant, coagulation, inflammatory and other gene classifications will be measured in vitro where transcription profiles of porcine endothelial cells exposed to oscillating and unidirectional flow will be analyzed. Using small interfering RNA, specific gene 'knock-downs' will be created (gene silencing) to determine the effect upon hemodynamic responses in vitro including perturbations of the phenotype as evaluated by microarray profiling with follow-up protein and proteomic studies.