Regulation of placenta growth factor by hemodynamics and reactive oxygen species

描述(由申请人提供)： 侧支动脉扩张(动脉生成)是一种生理过程，它可以绕过动脉粥样硬化的供应动脉，以保持远端组织的血液流动。因此，对动脉生成的药理刺激在治疗缺血性血管疾病方面可能是非常有益的，如冠状动脉疾病(CAD)和外周动脉疾病(PAD)。这样的治疗在糖尿病中尤其有价值，因为糖尿病1)严重增加了CAD和PAD的风险，2)抑制了天然(非刺激)动脉的形成。胎盘生长因子(PlGF，PGF)是一种与血管内皮生长因子相关的生长因子，通过动脉生成特异性地促进动脉扩张。因此，治疗性刺激PlGF的表达可能被用于促进动脉生成和改善冠心病和PAD患者的临床预后。然而，由于缺乏对调节血小板生长因子表达的基本机制(S)的了解，目前此类治疗是不可能的。我们的初步数据表明，在血管壁中存在一种新的调节PlGF表达的机制。此外，我们的证据表明，这种机制在糖尿病患者中是功能失调的。因此，PlGF表达失调可能是糖尿病患者动脉形成障碍的原因之一。本研究的长期目标是阐明在生理和病理生理条件下调节PlGF表达的关键机制。该项目将追求三个具体目标。具体目的1：建立控制PlGF在血管壁表达的基本调控机制。这些研究将在三个互补的模型系统中进行：静态培养的原代血管平滑肌细胞(SMC)；共同培养的承受剪应力的血管内皮细胞(EC)和SMC；以及分离的灌流小鼠血管。具体目标2：确定基本的PlGF调节机制中的关键步骤，这些步骤可由糖尿病改变。这些研究将证实目标1中发现的机制(S)的生理学相关性。这些实验将在高血糖(链脲佐菌素治疗)、高脂血症(高脂饮食治疗)和高血糖/高脂血症复合模型小鼠身上进行。这一设计将使我们能够1)确定通常发生在糖尿病中的复杂代谢功能障碍的哪个方面抑制PlGF的表达，以及2)精确地确定抑制PlGF表达的调控步骤。具体目标3：评估内源性PlGF表达增强刺激动脉生成的能力。这些研究将通过确定纠正AIM 2中揭示的信号缺陷是否可以1)逆转糖尿病患者PlGF表达的抑制，以及2)通过血管闭塞后发生动脉生成的能力来衡量功能改善，从而将AIM 2的结果提升到更高的水平。这些创新和新颖的研究将为调节一种重要的动脉形成因子提供重要的新信息，并将为正常化或增强PlGF表达可以改善糖尿病患者对血管闭塞(由于CAD或PAD)的动脉形成反应的想法提供“概念证明”。 公共卫生相关性：项目简介：缺血性心血管疾病(CVD)，如冠状动脉疾病，在糖尿病患者中高度流行，并占这一患者组死亡的大部分。刺激侧支动脉生长(动脉生成)以创造一个生理性的“搭桥”是一个很有前途的治疗概念；然而，在这种治疗成为现实之前，需要更多地了解控制动脉生成的机制。这项研究将探讨调节关键动脉生成生长因子PlGF的基本机制，为开发新的非侵入性治疗缺血性CVD奠定基础。

DESCRIPTION (provided by applicant): Collateral artery enlargement (arteriogenesis) is a physiological process that can 'bypass' atherosclerotic supply arteries to preserve blood flow to distal tissue. Thus, pharmacological stimulation of arteriogenesis could be highly beneficial in the treatment of ischemic vascular diseases, such as coronary artery disease (CAD) and peripheral artery disease (PAD). Such treatments would be especially valuable in the setting of diabetes, which both 1) severely increases the risk of CAD and PAD and 2) inhibits native (unstimulated) arteriogenesis. Placenta growth factor (PlGF, PGF) is a VEGF-related growth factor that specifically favors the expansion of arteries via arteriogenesis. Thus, therapeutic stimulation of PlGF expression could potentially be used to enhance arteriogenesis and improve clinical outcomes in patients with CAD and PAD. However, such treatments are not currently possible, due to a lack of understanding of the basic mechanism(s) regulating PlGF expression. Our preliminary data suggests the existence of a novel mechanism regulating PlGF expression in the vascular wall. Moreover, our evidence suggests that this mechanism is dysfunctional in diabetes. Thus, dysregulation of PlGF expression may contribute to faulty arteriogenesis in diabetics. The LONG TERM GOAL of this research is to elucidate key mechanisms regulating PlGF expression under physio- and patho-physiological conditions. This project will pursue three Specific Aims. Specific Aim 1: Establish the basic regulatory mechanism controlling PlGF expression in the vascular wall. These studies will be performed in three complementary model systems: primary vascular smooth muscle cells (SMC) in static culture; co- cultured vascular endothelial cells (EC) and SMC which are exposed to shear stress; and isolated perfused mouse vessels. Specific Aim 2: Identify key steps in the basic PlGF regulatory mechanism that are altered by diabetes. These studies will confirm the physiological relevance of the mechanism(s) uncovered in Aim 1. These experiments will be conducted in mouse models of hyperglycemia (streptozotocin treatment), hyperlipidemia (high-fat diet treatment) and combined hyperglycemia/hyperlipidemia. This design will allow us 1) to determine what facet of the complex metabolic dysfunction that typically occurs in diabetes inhibits PlGF expression, and 2) to pinpoint the regulatory step at which inhibition of PlGF expression occurs. Specific Aim 3: Assess the ability of enhanced endogenous PlGF expression to stimulate arteriogenesis. These studies will take the results of Aim 2 to the next level by determining whether correction of the signaling defect revealed in Aim 2 can 1) reverse the inhibition of PlGF expression in diabetes, and 2) result in functional improvement as measured by capacity to undergo arteriogenesis in response to vascular occlusion. These innovative and novel studies will provide essential new information about the regulation of an important arteriogenic factor and will provide "proof of concept" for the idea that normalizing or enhancing PlGF expression can improve the arteriogenic response to vascular occlusion (due to CAD or PAD) in patients with diabetes. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE Ischemic cardiovascular diseases (CVD) such as coronary artery disease are highly prevalent in diabetics and account for most of the mortality in this patient group. Stimulation of collateral artery growth (arteriogenesis) to create a physiological "bypass" is a promising treatment concept; however, greater understanding of the mechanisms controlling arteriogenesis is needed before such treatments are a reality. This research will investigate fundamental mechanisms regulating the key arteriogenic growth factor PlGF as a basis for developing new, noninvasive treatments for ischemic CVD.