Regulation of placenta growth factor by hemodynamics and reactive oxygen species

描述（由申请人提供）： 侧支动脉扩大（动脉生成）是一个生理过程，可以“绕过”动脉粥样硬化供应动脉，以保持血流到远端组织。因此，动脉生成的药理学刺激在治疗缺血性血管疾病如冠状动脉疾病（CAD）和外周动脉疾病（PAD）中可能是非常有益的。这种治疗在糖尿病的情况下尤其有价值，糖尿病1）严重增加CAD和PAD的风险，2）抑制天然（未刺激的）动脉生成。胎盘生长因子（PlGF，PGF）是一种VEGF相关的生长因子，特别有利于通过动脉生成扩张动脉。因此，PlGF表达的治疗性刺激可潜在地用于增强CAD和PAD患者的动脉生成并改善临床结果。然而，由于缺乏对调节PlGF表达的基本机制的理解，这种治疗目前是不可能的。我们的初步数据表明，存在一种新的机制调节PlGF在血管壁中的表达。此外，我们的证据表明，这种机制在糖尿病中是功能失调的。因此，PlGF表达失调可能导致糖尿病患者动脉生成不良。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。该项目将实现三个具体目标。具体目的1：建立控制血管壁中PlGF表达的基本调节机制。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）;暴露于剪切应力的共培养血管内皮细胞（EC）和SMC;以及分离的灌注小鼠血管。具体目标2：确定糖尿病改变的基本PlGF调节机制的关键步骤。这些研究将证实目标1中发现的机制的生理相关性。这些实验将在高血糖症（链脲佐菌素治疗）、高脂血症（高脂饮食治疗）和高血糖症/高脂血症合并的小鼠模型中进行。这种设计将允许我们1）确定通常在糖尿病中发生的复杂代谢功能障碍的哪个方面抑制PlGF表达，和2）精确定位PlGF表达抑制发生的调节步骤。具体目的3：评估增强的内源性PlGF表达刺激动脉生成的能力。这些研究将通过确定Aim 2中揭示的信号传导缺陷的校正是否可以1）逆转糖尿病中PlGF表达的抑制，和2）导致功能改善，将Aim 2的结果提升到下一个水平，如通过响应于血管闭塞而经历动脉生成的能力所测量的。这些创新和新颖的研究将提供关于重要的动脉生成因子的调节的基本新信息，并将为以下想法提供“概念证明”：使PlGF表达正常化或增强PlGF表达可以改善糖尿病患者对血管闭塞（由于CAD或PAD）的动脉生成反应。 公共卫生相关性：缺血性心血管疾病（CVD）如冠状动脉疾病在糖尿病患者中非常普遍，并占该患者组的大部分死亡率。刺激侧支动脉生长（动脉生成）以创建生理“旁路”是一个有前途的治疗概念;然而，在这种治疗成为现实之前，需要对控制动脉生成的机制有更深入的了解。这项研究将探讨调节关键动脉生长因子PlGF的基本机制，作为开发缺血性CVD新的非侵入性治疗方法的基础。

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.