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

项目摘要/摘要 血管胰岛素抵抗是2型糖尿病(T2D)和抑制胰岛素诱导的标志 血管扩张是其主要后果。值得注意的是，在T2D中，胰岛素刺激的血管扩张和血液减少 流向骨骼肌等组织会显著限制葡萄糖的摄取，并导致血糖受损 控制力。详细了解导致缺陷的原因和机制 胰岛素的血管扩张作用对于发展旨在改善的治疗策略至关重要 血糖控制和预防心血管疾病。基于我们以前的工作和最新的 令人兴奋的初步数据，我们提出了新的假设，ADAM17介导的胰岛素释放 内皮细胞分泌的受体α(IRα)可抑制胰岛素刺激的T2D血管扩张。我们进一步建议 内皮细胞ADAM17活性的增加归因于蛋白激酶C(PKC)的激活和 随后磷脂酰丝氨酸(PS)外化到细胞膜的外层小叶，其作用是 将ADAM17引导至其目标底物。AS外源PS是ADAM17脱落酶的竞争性抑制物 活性，我们还将确定口服PS恢复血管胰岛素敏感性的有效性 在T2D患者中。我们将用获得和失去功能的基因操作来检验我们的创新假说 在病人分离的阻力动脉中培养的人内皮细胞的实验 正在接受腹部手术，以及患有T2D的患者。实验结果将决定PS的作用 外化-ADAM17激活-IRα脱落作为一种损害胰岛素血管扩张作用的机制 在T2D中。具体地说，在目标1中，我们将确定PKC导致外部化的机制 PS是否需要PS外化以依赖PKC激活内皮细胞中的ADAM17。 接下来，在目标2中，我们将确定ADAM17活性在IRα脱落和随后的损伤中的作用。 T2D中胰岛素刺激的血管扩张。最后，在目标3中，我们将进行随机双盲临床试验。 口服ADAM17脱氢酶竞争性抑制剂的疗效观察 T2D患者胰岛素刺激腿血流量的PS活性。我们队准备前进一步 心血管和糖尿病研究向前推进，该项目将对整个世界产生持续、强大的影响 在概念上、机制上、方法上和 从治疗上讲。事实上，这一提议代表了我们目前机械论理解的范式转变 血管胰岛素抵抗。针对ADAM17激活具有纠正的非凡前景 血管胰岛素抵抗与T2D相关代谢和心血管疾病的最终防治 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.