Regulation of placenta growth factor by hemodynamics and reactive oxygen species

项目总结 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 由外周动脉疾病(PAD)引起。PAD影响了大约1000万美国人，并对临床产生了毁灭性的影响； 目前的治疗方法往往不能提供长期的好处，截肢是患者的最终选择 严重的肢体缺血。在美国，超过90%的非创伤相关肢体截肢是由PAD引起的。 动脉生成，血管系统通过扩大先前存在的侧支而绕过闭塞的能力 动脉，可以改善PAD患者的血流；不幸的是，II型糖尿病抑制了动脉的形成。自.以来 对于糖尿病患者使用PAD，刺激动脉生成具有巨大的价值，我们必须 理解1)动脉形成的关键机制，以及2)这些机制如何被II型糖尿病阻断。胎盘 生长因子(PLGF)特异性地诱导动脉生成，是这一过程中的关键启动因子。然而， 关于PLGF水平是如何控制的，人们知之甚少。在之前的奖项中，我们有了几项重要发现 这揭示了一种新的机制，将PLGF上调与流体切应力的动脉信号联系起来 (FSS)。此外，我们还证实，西方饮食抑制了闭塞诱导的骨骼中PLGF的表达 肌肉，并对其中涉及的机制有了深入的了解。本应用程序的总体目标是1)到 进一步加深我们对PLGF调节机制的了解，以及2)揭示一种 西式饮食会损害PLGF的调节。我们的中心假设是：1)FSS通过一种新的方式上调PLGF 铁依赖途径；2)西方饮食通过诱导持续的 高血糖症。这些假设得到了我们已发表的结果和初步数据的有力支持。我们 将实现三个具体目标。特殊目标1将扩大我们对分子的理解 体外流体剪应力上调PLGF的机制。这些研究利用了一种内皮细胞 细胞/平滑肌细胞共培养模型；脉冲式FSS采用锥板装置。这款车 是根据之前的奖励在我们的实验室建立的。《特殊目标2》将扩展我们对分子的认识 FSS体外、体内外系统上调PLGF的机制。这些产品的型号 研究是分离的小鼠外周小动脉和小鼠股动脉的渐进性闭塞；两者都是 在我们的实验室建立。特定目标3将发现西方饮食引起的分子机制(S) PLGF调节功能失调。这些研究是在培养的细胞和分离的外周小动脉中进行的。 和表现出长期西方饮食引起的一系列代谢功能障碍的小鼠的缺血后肢 消费。这些研究将揭示调节这种关键的动脉生长的新机制。 并将确定潜在治疗干预措施的新靶点，以促进糖尿病患者的动脉生成 垫子。

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.