Systems Biology Analyses for Hemodynamic Regulation of Vascular Homeostasis

描述(由申请人提供)：动脉粥样硬化病变的局灶性表明，血液动力学力量对于调节健康和疾病中的血管内稳态至关重要。血管内皮细胞(ECs)对血流动力的反应在这种调节中起着重要作用。体内研究表明，分支点的内皮细胞表达促动脉粥样硬化的表型。相比之下，动脉树笔直部分的内皮细胞 暴露于高切变流和大的净向前方向，这些区域通常不会发生动脉粥样硬化。等人和我们的体外研究表明，模拟动脉树直段流动状态的恒定和脉动切应力(PS)模拟动脉树直段的流动状态，诱导参与抗增殖、抗氧化、抗炎和维持血管张力的基因，具有降低细胞周转、防止白细胞募集、促进伤口愈合和适应性重塑等动脉粥样硬化保护作用。相反，没有显著正向的振荡切应力(OS)通过激活促增殖、促氧化和促炎症基因而导致动脉粥样硬化。我们假设，虽然PS和OS可能在初始阶段激活类似的信号事件，但结果将随着时间的推移而不同。信号网络的时间依赖映射将导致基因表达谱的时间分辨率，从而导致PS与OS的不同功能后果。在这个拟议的项目中，我们将研究PS和OS下ECs的信号、转录调控和功能表型随时间的变化。绘制这些流动条件下的不同途径需要使用系统生物学方法，提供对压力的不同反应的综合机制和网络视角。为了系统地绘制EC功能的流程调控图，我们提出了以下具体目标：(1)建立PS VS、OS下EC信号事件的时间图。(2)探讨PS VS、OS对EC基因表达的转录调控。(3)检测PS VS、OS条件下内皮细胞表型反应的时间分辨率。(4)通过重构信号模型，整合分子事件和EC功能。(5)验证已确定的EC信号事件和基因在小鼠动脉树中的表达。在这些特定的目标下，我们将进行系统的实验，以获得系统生物学分析所需的数据，以构建EC分子事件和功能后果的生理和病理调节的分子和途径模型。这种整合和协作的系统生物学方法将对机械转导的复杂过程产生新的见解，通过不同的流动模式调节动脉壁的动态平衡。这些发现将极大地提高我们对动脉粥样硬化的分子和力学基础的理解，动脉粥样硬化是心血管疾病中的一种主要病理生理事件。

DESCRIPTION (provided by applicant): The focal nature of the atherosclerotic lesions indicates that hemodynamic forces are critical for the regulation of vascular homeostasis in health and disease. Responses of vascular endothelial cells (ECs) to hemodynamic forces play significant roles in such regulations. In vivo studies implicate that the ECs in branch points express pro-atherogenic phenotypes. In contrast, ECs in the straight parts of the arterial tree are exposed to high shear flow with a large net forward direction, and these regions are generally spared from atherosclerosis. The in vitro studies by others and us suggest that steady and pulsatile shear stresses (PS) with a net forward direction, which simulates the flow condition at the straight part of the arterial tree, induce genes involved in anti-proliferation, anti-oxidation anti-inflammation, and maintenance of vascular tone, with athero-protective effects such as reduction of cell turnover, prevention of white cell recruitment, promotion of wound healing, and adaptive remodeling. In contrast, oscillatory shear stress (OS) without a significant forward direction is atherogenic by activating pro-proliferative, pro-oxidative, and pro-inflammatory genes. We hypothesize that, while PS and OS may activate similar signaling events at the initial stage, the results will diverge with time. Time-dependent mapping of the signal networks will lead to temporal resolution of the gene expression profiles, hence the differential functional consequences of PS vs. OS. In this proposed project, we will examine the signaling, transcriptional regulations, and functional phenotypes of ECs under PS and OS over time. Mapping the differential pathways under these flow conditions requires the use of systems biology approaches that provides a comprehensive mechanistic and network perspective on the diferential responses to stresses. In order to systematically map the flow-regulation of EC functions, we propose the following specific aims: (1) To establish the temporal map of EC signaling events under PS vs, OS. (2) To investigate the transcriptional regulations of EC gene expression under PS vs, OS. (3) To examine the temporal resolution of phenotypic responses of ECs under PS vs, OS. (4) To integrate molecular events and EC functions by reconstruction of signaling models. (5) To validate the defined EC signaling events and gene expressions in mouse arterial tree. Under these Specific Aims, we will conduct experiments systematically to obtain the data necessary for the systems biology analyses to construct the molecular and pathway models for the physiological and pathological regulations of EC molecular events and functional consequences. This integrative and collaborative systems biology approach will generate new insights into the intricate process of mechanotransduction by which different flow patterns modulate homeostasis in the arterial wall. These findings will greatly enhance our understanding of the molecular and mechanical bases of atherosclerosis, a major pathophysiological event in cardiovascular diseases.