Redox regulation of endothelial function and wound healing

描述(由申请人提供)：糖尿病患者的伤口愈合障碍是一个特别具有挑战性的临床问题，目前还没有有效的治疗方案。内皮细胞功能障碍是创面愈合受损的重要原因。糖尿病血管内皮细胞功能障碍的一个主要特征是高血糖通过线粒体电子传递链介导的超氧阴离子过量产生，从而导致氧化应激。我们的初步数据表明，糖尿病患者体内超氧化物歧化似乎削弱了三种内皮因子在伤口愈合中的作用--四氢生物蝶呤(BH4)和内皮型一氧化氮合酶(ENOS)、内皮细胞形态发生原声学刺激物(SHH)和内皮祖细胞(EPC)。然而，值得注意的是，人们对超氧化物诱导的氧化应激如何调节这些伤口修复的核心因素知之甚少。这些知识对于成功调节内皮功能以改善糖尿病患者的伤口愈合至关重要。例如，发现糖尿病EPC的缺陷并纠正它们的方法可能会导致糖尿病伤口的自体细胞疗法。该项目将重点研究氧化应激诱导的内皮功能障碍在糖尿病伤口修复中的作用，从而填补这方面知识的重大空白。我们假设糖尿病创面的氧化应激是eNOS、Sonic Hedgehog和内皮前体细胞三种修复介质功能障碍的共同原因，导致愈合受阻。为了验证这一假设，我们将使用链脲佐菌素诱导的1型糖尿病小鼠来实现三个特定的目标。在目标1中，我们将确定氧化应激如何损害皮肤eNOS的功能，重点是其基本辅因子BH4的作用。在目标2中，我们将确定声波刺猬在氧化应激下调节糖尿病创面愈合的机制。在目标3中，我们将确定内皮祖细胞如何在1型糖尿病中变得功能失调。这项研究的主要意义在于，它将首次确定超氧化物如何以一种综合的方式调节内皮功能和伤口修复，这可能为影响1型糖尿病伤口愈合的相互关联的机制提供新的知识，从而解决创伤愈合的系统生物学和病理生理学中的一个基本问题。

DESCRIPTION (provided by applicant): Wound healing impairment in diabetic patients represents a particular challenging clinical problem to which no efficacious treatment regimens exist. Endothelial cell dysfunction is a significant contributor to impaired wound healing. A cardinal feature of endothelial dysfunction in diabetes is hyperglycemia- mediated superoxide anion overproduction by the mitochondrial electron transport chain with resultant oxidative stress. Our preliminary data suggest that increased superoxide in diabetes appears to impair the functions of three endothelial factors on wound healing - tetrahydrobiopterin (BH4) and endothelial nitric oxide synthase (eNOS), endothelial morphogen sonic hedgehog (SHH), and endothelial progenitor cells (EPCs). Yet remarkably little is known about how superoxide-induced oxidative stress regulates these factors central to wound repair. Such knowledge is critical for successfully modulating endothelial function to improve wound healing in diabetes. For example, discovery of the defects in diabetic EPC and the means to correct them could lead to autologous cell therapies for diabetic wounds. This project will focus on oxidative stress-induced endothelial dysfunction in diabetic wound repair, thus filling a significant gap in such knowledge. We hypothesize that oxidative stress in diabetic wounds is a common cause for the dysfunction of the three repair mediators - eNOS, sonic hedgehog and endothelial progenitor cells, resulting in impaired healing. To test this hypothesis, we will pursue three specific aims using streptozotocin-induced type 1 diabetic mice. In aim 1, we will determine how oxidative stress impairs cutaneous eNOS function, focusing on the role of its essential cofactor BH4. In Aim 2, we will determine the mechanism through which sonic hedgehog regulates diabetic wound healing under oxidative stress. In Aim 3, we will determine how endothelial progenitor cells become dysfunctional in type 1 diabetes. The major significance of the proposed studies is that it will for the first time determine how superoxide regulates endothelial function and wound repair in an integrated fashion, which may provide new knowledge regarding an interconnected mechanism that affects wound healing in type 1 diabetes, thus addressing a fundamental issue in system biology and pathophysiology of wound healing.