Targeting ADAM17 activity for correction of vascular insulin resistance in type 2 diabetes

项目总结/摘要 血管胰岛素抵抗是2型糖尿病（T2 D）的标志，并且抑制胰岛素诱导的胰岛素抵抗。 血管舒张是其主要后果。值得注意的是，在2型糖尿病患者中，胰岛素刺激的血管舒张和血液循环减少， 流向骨骼肌等组织的血流显著限制了葡萄糖摄取 控制详细了解的诱发因素和机制的缺陷， 胰岛素的血管扩张作用对于开发旨在改善胰岛素抵抗的治疗策略是至关重要的。 血糖控制和预防心血管疾病。根据我们之前的工作和最近的工作， 令人兴奋的初步数据，我们提出了新的假设，即ADAM 17介导的胰岛素脱落， 来自内皮细胞的受体α（IRα）损害T2 D中胰岛素刺激的血管舒张。我们进一步建议 内皮细胞ADAM 17活性的增加归因于蛋白激酶C（PKC）的激活， 随后磷脂酰丝氨酸（PS）外化到细胞膜的外小叶， 引导ADAM 17到达其靶向底物。外源PS是ADAM 17脱落酶的竞争性抑制剂 活性，我们还将确定口服PS恢复血管胰岛素敏感性的疗效 在T2 D患者中我们将通过获得和丧失功能的基因操作来测试我们的创新假设。 在人培养的内皮细胞中的实验，在从患者采集的分离的阻力动脉中的实验 接受腹部手术和T2 D患者。实验结果将确定PS的作用 外化-ADAM 17激活-IR α脱落作为损害胰岛素血管舒张作用的机制 在T2 D。具体来说，在目标1中，我们将确定PKC引起细胞外化的机制。 PS和PS外化是否需要PKC依赖性激活内皮细胞中的ADAM 17。 接下来，在目标2中，我们将确定ADAM 17活性在IRα脱落和随后的IR α损伤中的作用。 2型糖尿病胰岛素刺激血管舒张。最后，在目标3中，我们将进行随机双盲临床试验 为了确定口服施用ADAM 17脱落酶的竞争性抑制剂的治疗功效， 活动，PS，对胰岛素刺激的腿部血流量与T2 D患者。我们的队伍已经准备好 心血管和糖尿病研究向前推进一个项目，将发挥持续的，强大的影响， 在概念上、机械上、方法上新颖的一些层次的探究， 治疗上事实上，这个提议代表了我们目前机械理解的范式转变 血管性胰岛素抵抗靶向ADAM 17激活为纠正 血管胰岛素抵抗和最终预防/治疗T2 D相关的代谢和心血管疾病 疾病

PROJECT SUMMARY/ABSTRACT Vascular insulin resistance is a hallmark of type 2 diabetes (T2D) and dampening of insulin-induced vasodilation is its primary consequence. Notably, in T2D, reduced insulin-stimulated vasodilation and blood flow to tissues such as skeletal muscle significantly limits glucose uptake and contributes to impaired glucose control. A detailed understanding of the precipitating factors and mechanisms underlying the defects in vasodilator actions of insulin is critical for the development of therapeutic strategies aimed at improving glycemic control and protecting against cardiovascular disease. Based on our prior work and most recent and exciting preliminary data, we propose the novel hypothesis that ADAM17-mediated shedding of the insulin receptor alpha (IRα) from endothelial cells impairs insulin-stimulated vasodilation in T2D. We further propose that the increased activity of endothelial ADAM17 is attributed to protein kinase-C (PKC) activation and subsequent externalization of phosphatidylserine (PS) to the outer leaflet of the cell membrane, which serves to guide ADAM17 to its targeted substrates. As exogenous PS is a competitive inhibitor of ADAM17 sheddase activity, we will also determine the efficacy of oral administration of PS for restoring vascular insulin sensitivity in T2D patients. We will test our innovative hypotheses with gain- and loss-of-function genetic-manipulation experiments in human cultured endothelial cells, in isolated resistance arteries harvested from patients undergoing abdominal surgery, and in patients with T2D. Experimental results will determine the role of PS externalization-ADAM17 activation-IRα shedding as a mechanism impairing the vasodilatory actions of insulin in T2D. Specifically, in Aim 1, we will determine the mechanism by which PKC causes the externalization of PS and whether PS externalization is needed for PKC-dependent activation of ADAM17 in endothelial cells. Next, in Aim 2, we will determine the role of ADAM17 activity in IRα shedding and subsequent impairment of insulin-stimulated vasodilation in T2D. Finally, in Aim 3, we will perform a randomized double-blind clinical trial to determine the therapeutic efficacy of oral administration of the competitive inhibitor of ADAM17 sheddase activity, PS, on insulin-stimulated leg blood flow in patients with T2D. Our team is poised to move cardiovascular and diabetes research forward with a project that will exert a sustained, powerful impact across a number of levels of inquiry that are novel conceptually, mechanistically, methodologically, and therapeutically. Indeed, this proposal represents a paradigm shift from our current mechanistic understanding of vascular insulin resistance. Targeting ADAM17 activation holds extraordinary promise for correcting vascular insulin resistance and ultimately preventing/treating T2D-associated metabolic and cardiovascular diseases.