Regulation of placenta growth factor by hemodynamics and reactive oxygen species

项目摘要 II型糖尿病患者患心血管疾病的风险非常高，50岁以上的糖尿病患者中约有30%患有心血管疾病。 外周动脉疾病（PAD）PAD影响约1000万美国人，并具有破坏性的临床影响; 目前的治疗往往不能提供长期的好处，截肢是患者的最终选择， 严重肢体缺血在美国，超过90%的非创伤性截肢是由于PAD。 动脉生成，血管系统通过扩大预先存在的侧支绕过闭塞的能力 动脉，可以改善PAD患者的血流量;不幸的是，II型糖尿病抑制动脉生成。以来 刺激动脉生成对PAD糖尿病患者具有巨大价值，我们必须 理解1）动脉生成的关键机制和2）这些如何被II型糖尿病阻断。胎盘 生长因子（PLGF）特异性诱导动脉生成，并且是该过程中的关键起始因子。然而，在这方面， 关于PLGF水平是如何控制的知之甚少。我们在先前的奖项下取得了几项关键发现 这揭示了一种新的机制，将PLGF的上调与流体剪切应力的动脉信号联系起来， （FSS）。此外，我们还证实了西方饮食抑制了闭塞诱导的骨骼肌中PLGF的表达。 肌肉，并获得了有关机制的见解。本申请的总体目标是：1） 进一步追求我们对PLGF调节机制的认识，以及2）揭示一种 西方饮食损害PLGF调节。我们的中心假设是：1）FSS通过一种新的 铁依赖性途径;和2）西方饮食通过诱导持续的PLGF表达来抑制PLGF表达 高血糖症这些假设得到了我们发表的结果和初步数据的有力支持。我们 实现三个具体目标。具体目标1将扩大我们对分子的理解， 体外流体剪切应力上调PLGF的机制。这些研究利用内皮细胞 细胞/平滑肌细胞共培养模型;脉动FSS用锥板装置施加。该模型 是在我们实验室里建立的具体目标2将扩展我们的分子知识 从体外到离体和体内系统，FSS上调PLGF的机制。模型对于这些 研究是分离的小鼠外周小动脉和小鼠中逐渐的股动脉闭塞;两者都是 建立在我们的实验室。具体目标3将发现西方饮食引起的分子机制 功能失调的PLGF调节。这些研究是在培养的细胞和分离的外周小动脉中进行的 和缺血后肢的小鼠表现出一系列的代谢功能障碍诱导的长期西方饮食 消费这些研究将揭示新的机制，调节这种关键的动脉生长的表达 因素，并将确定潜在的治疗干预的新靶点，以增强糖尿病患者的动脉生成。 垫.

PROJECT SUMMARY Type II diabetics are at very high risk for cardiovascular diseases, and ~30% of diabetics over age 50 suffer from peripheral artery disease (PAD). PAD affects ~10 million Americans and has a devastating clinical impact; current treatments often fail to provide long-term benefits, and amputation is the final option for patients with critical limb ischemia. More than 90% of non-trauma related limb amputations in the US are due to PAD. Arteriogenesis, the ability of the vasculature to bypass occlusion via enlargement of pre-existing collateral arteries, could improve blood flow in PAD patients; unfortunately, type II diabetes inhibits arteriogenesis. Since stimulation of arteriogenesis would be of enormous value in diabetics with PAD, it is essential that we comprehend 1) key mechanisms of arteriogenesis and 2) how these are blocked by type II diabetes. Placental growth factor (PLGF) specifically induces arteriogenesis and is a key initiating factor in the process. However, little is known about how PLGF levels are controlled. We made several key discoveries under the prior award that revealed a novel mechanism linking upregulation of PLGF to the arteriogenic signal of fluid shear stress (FSS). Furthermore, we established that a Western diet inhibits occlusion-induced PLGF expression in skeletal muscle, and gained insights into the mechanism involved. The overall objectives of this application are 1) to further pursue our knowledge of mechanisms regulating PLGF, and 2) to reveal the mechanism by which a Western diet impairs PLGF regulation. Our central hypotheses are: 1) FSS upregulates PLGF via a novel iron-dependent pathway; and 2) a Western diet inhibits PLGF expression by inducing sustained hyperglycemia. These hypotheses are strongly supported by our published results and preliminary data. We will accomplish three Specific Aims. Specific Aim 1 will expand our understanding of the molecular mechanism for upregulation of PLGF by fluid shear stress in vitro. These studies utilize an endothelial cell/smooth muscle cell co-culture model; pulsatile FSS is applied with a cone and plate device. This model was established in our lab under the prior award. Specific Aim 2 will extend our knowledge of the molecular mechanism for upregulation of PLGF by FSS from in vitro to ex vivo and in vivo systems. Models for these studies are isolated mouse peripheral arterioles and gradual femoral artery occlusion in mice; both are established in our lab. Specific Aim 3 will discover molecular mechanism(s) by which a Western diet causes dysfunctional PLGF regulation. These studies are done in cultured cells, and in isolated peripheral arterioles and ischemic hindlimbs of mice exhibiting a range of metabolic dysfunction induced by long-term Western diet consumption. These studies will reveal novel mechanisms regulating expression of this key arteriogenic growth factor and will identify new targets for potential therapeutic interventions to enhance arteriogenesis in diabetic PAD.