音猬因子修复糖尿病血管损伤的机制研究

About 92 million people in China are suffering from diabetes, a condition that frequently leads to impaired angiogenesis and delayed wound healing resulting in lower extremity ulcers and amputations. Impaired angiogenesis contributes to poor wound blood flow in diabetic patients, which impedes the optimal endogenous regenerative and repair responses. Sonic hedgehog (SHH), a regulatory protein belongs to a family of proteins called "morphogens", has been found central to vascular development and hair growth, both of which are vital in the scheme of wound healing. Reports from our laboratory and others demonstrated that deficient cutaneous SHH signaling results delayed wound healing in diabetes. Remarkably, the mechanisms underlying how SHH is regulated to affect angiogenesis and tissue regeneration during wound healing are poorly understood. Our preliminary data demonstrated that thrombospondin-1(TSP-1) depletion activate cutaneous SHH signaling in diabetes. Caveolin-1, the major coat protein of caveolae, was found critically involved in eNOS activity, but how its role in the regulation of SHH in wound healing remains to be addressed. Lack of such knowledge, it is highly unlikely to acquire the ability to therapeutically modulate impaired angiogenesis in diabetic wounds. The objective of this proposal is to determine the mechanisms underlying the regulation of SHH during wound repair in diabetes. Our central hypothesis is that deficient sonic hedgehog signaling contributes to refractory wound healing in diabetes, which is rescued by depletion of thrombospondin-1 (TSP-1). We first hypothesize that caveolin-1 binds with SHH to inhibit SHH signaling activation, leading to eNOS dysfunction. We further hypothesize that through its receptor CD36 or CD47,TSP-1 leads to deficient SHH signaling in diabetic wounds, resulting in either reduction of SHH ligand or facilitation of the inhibitory effects of caveolin-1 on eNOS. We will test our hypothesis by performing two Objectives encompassing in vitro and in vivo studies utilizing SHH, caveolin-1 and TSP-1 deficient mice. In Objective 1, we will determine how caveolin-1 modulates SHH signaling during wound healing in diabetes. In Objective 2, we will determine how TSP-1 depletion increases skin SHH pathway in diabetes. Our ultimate goal is to rescue wound tissue regeneration in patients with diabetes. Understanding the key molecular interactions during wound repair will help us launch new therapeutic targets for wound care.

我国有 9240 万成年人患糖尿病，伤口不愈导致截肢是其重要并发症。音猬因子是一种形态发生原，对血管生长有重要调节作用。获知音猬因子的调节通路是促进组织修复再生并向临床转化的不可缺少的一步。我们前期工作表明糖尿病音猬因子信号通路受损是糖尿病伤口愈合延迟的重要原因，并受凝血酶敏感蛋白-1和小凹蛋白-1调节，但具体机制尚不清楚。本课题假设糖尿病时音猬因子通路受凝血酶敏感蛋白-1和小凹蛋白-1抑制,使血管内皮细胞新生功能受损导致伤口难以愈合，结合体内和体外试验，利用实验室已有的多种基因缺陷动物（音猬因子,小凹蛋白-1,凝血酶敏感蛋白-1,CD36,CD47等），通过两个主要部分来验证我们的假设:1）研究小凹蛋白-1如何调节音猬因子对内皮一氧化氮合酶和糖尿病伤口愈合的影响; 2）研究凝血酶敏感蛋白-1通过 何种受体调节音猬因子和糖尿病伤口愈合。本项目将深入探讨音猬因子在血管新生和伤口愈合的调控机制

我国有 9240 万成年人患糖尿病，伤口不愈导致截肢是其重要并发症。音猬因子是一种形态发生原，对血管生长有重要调节作用。获知音猬因子的调节通路是促进组织修复再生并向临床转化的不可缺少的一步。我们前期工作表明糖尿病音猬因子信号通路受损是糖尿病伤口愈合延迟的重要原因，并受凝血酶敏感蛋白-1和小凹蛋白-1调节，但具体机制尚不清楚。本课题假设糖尿病时音猬因子通路受凝血酶敏感蛋白-1和小凹蛋白-1抑制,使血管内皮细胞新生功能受损导致伤口难以愈合，结合体内和体外试验，利用实验室已有的多种基因缺陷动物（音猬因子,小凹蛋白-1,凝血酶敏感蛋白-1,CD36,CD47等），通过两个主要部分来验证我们的假设:1）研究小凹蛋白-1如何调节音猬因子对内皮一氧化氮合酶和糖尿病伤口愈合的影响; 2）研究凝血酶敏感蛋白-1通过何种受体调节音猬因子和糖尿病伤口愈合。本项目将深入探讨音猬因子在血管新生和伤口愈合的调控机制。 本课题发现音猬因子是调节糖尿病伤口愈合中血管新生的重要因子，它通过促进血管内皮祖细胞中一氧化碳合酶的表达和活性来改善血管内皮祖细胞的功能，并促进血管新生的发生。我们进一步发现，音猥因子受到凝血酶敏感蛋白-1的负向调节，在糖尿病的情况下，凝血酶敏感蛋白-1水平升高，抑制了音猥因子信号通路传导，造成血管新生障碍，而凝血酶敏感蛋白-1的这一作用主要是通过其受体CD36来实现的。本课题部分结果发表在American Journal of Physiology - Endocrinology & Metabolism 以及 Journal of Visualized Experiments 上。 我们相信，了解伤口修复过程中的关键分子相互作用将有助于我们推出新的治疗靶点的伤口护理。