Mechanical regulation of vascular metabolism

该提案概述了大卫吴博士的研究计划，在Gokhan Mutlu博士和Yun Fang博士的实验室进行为期两年的博士后培训。该研究项目的最终目标是在血管生物学方面做出可能有助于促进人类健康的发现;另一个目标是熟练掌握细胞和分子生物学的基本技术，并最终启动一项研究计划，以最终申请血管生物学K级奖。在为期2年的指导期间，吴博士将从芝加哥大学的导师和咨询委员会获得额外的学术和科学指导。总体研究目标是确定切应力对内皮细胞（EC）代谢的作用，这在内皮激活中起着重要作用。内皮细胞活化是EC具有降低的屏障功能和增加的炎症的过程。糖酵解的显著上调导致内皮细胞活化是最近发现的现象。由“动脉粥样硬化酮”血流产生的低剪切应力（与正常“动脉粥样硬化保护”血流期间的高剪切应力相反）在确定内皮激活中是重要的，这也被充分描述。然而，剪切力的变化如何引起内皮细胞代谢的变化尚不清楚。吴博士现在有证实性的数据表明，人主动脉内皮细胞（HAEC）暴露于动脉粥样硬化酮流上调糖酵解，血管生成和炎症的关键酶。Wu博士也有初步的数据表明HAEC不能使用它们的线粒体在动脉粥样硬化流动下产生能量。令人兴奋的是，他最近发现，动脉粥样硬化酮流动导致转录因子缺氧诱导因子-1 α（HIF-1α）的常氧稳定，已知HIF-1α在许多其他情况下上调糖酵解。这是违反直觉的，因为HIF-1α活性被认为在高氧分压环境中受到抑制，例如在动脉血流中。此外，Wu博士发现溶血磷脂酸（LPA）信号，增加动脉粥样硬化蛋白流（并通过RhoA和Rac 1，调节细胞骨架组织的小GTP酶起作用），也被认为是动脉粥样硬化的关键介质，也诱导HIF-1α。总的来说，这些结果导致了他的中心假设：通过RhoA或Rac 1的Atheroprone流量介导的LPA信号转导调节以HIF-1α依赖性方式导致代谢变化。目的1将检验以下假设：HIF-1α稳定化对于糖酵解、线粒体功能不全和动脉粥样硬化流下EC活化的上调是必需的。目的2将检验以下假设：atheroprone流量通过RhoA和Rac 1通过LPA信号传导稳定HIF-1α。我们的目标是实现一个机械的理解剪切应力相关的变化代谢。内皮活化在动脉粥样硬化蛋白流动状态（靠近瓣膜和动脉分支点）中自然发生-这导致慢性炎症并最终导致动脉粥样硬化，这是美国发病率和死亡率的主要原因。因此，有一个显着的需要，以更好地了解剪切应力如何诱导代谢变化，因此EC激活。

The proposal outlines a research plan for David Wu, MD PhD, to perform postdoctoral training in the laboratories of Gokhan Mutlu, MD, and Yun Fang, PhD, for two years. The ultimate goal of this research project is to make discoveries in vascular biology that could be useful in promoting human health; another goal is to be- come fluent in the basic techniques in cellular and molecular biology, and ultimately to jump start a research program for the eventual application of a K-level award in vascular biology. During the 2 year mentored period, Dr. Wu will receive additional academic and scientific guidance from the mentors and an advisory committee at the University of Chicago. The overall research goal is to determine the role that shear stress plays on endothelial cell (EC) metabolism, which plays a fundamental role in endothelial activation. Endothelial activation is the process by which ECs have reduced barrier function and increased inflammation. That endothelial activation occurs with a significant upregulation of glycolysis is a recently discovered phenomenon. That low shear stress generated by “atheroprone” blood flow (as opposed to high shear stress during normal, “atheroprotective” blood flow) is important in determining endothelial activation is also well-described. However, how changes in shear stress produce changes in the metabolism of ECs is unknown. Dr. Wu now has confirmatory data that human aortic endothelial cells (HAECs) exposed to atheroprone flow upregulate key enzymes in glycolysis, angiogenesis, and inflammation. Dr. Wu also has preliminary data that suggests HAECs are unable to use their mitochondria to generate energy under atheroprone flow. Excitingly, he recently found that atheroprone flow led to normoxic stabilization of transcription factor hypoxia inducible factor-1α (HIF-1α), which is known to upregulate glycolysis in many other contexts. This is counterintuitive, as HIF-1α activity is thought to be suppressed in high oxygen tension settings, such as in arterial blood flow. Furthermore, Dr. Wu found that lysophosphatidic acid (LPA) signaling, increased in atheroprone flow (and working through RhoA and Rac1, small GTPases which modulate cytoskeletal organization), and also known to be a key mediator of atherosclerosis, also induces HIF-1α. Collectively, these results led to his central hypothesis: atheroprone flow-mediated modulation of LPA signaling through RhoA or Rac1 leads to metabolic changes in a HIF-1α dependent manner. Aim 1 will test the hypothesis that HIF-1α stabilization is required for upregulation of glycolysis, mitochondrial insufficiency, and EC activation under atheroprone flow. Aim 2 will test the hypothesis that atheroprone flow stabilizes HIF-1α through LPA signaling via RhoA and Rac1. The goal is to achieve a mechanistic understanding of shear-stress related changes in metabolism. Endothelial activation occurs naturally in atheroprone flow states (near valves and arterial branch points) – this results in chronic inflammation and ultimately atherosclerosis, a leading cause of morbidity and mortality in the United States. Thus, there is a significant need to better understand how shear stress induces metabolic changes and hence EC activation.