MicroRNA Regulation of Endothelial Progenitor Cell Function and Wound Healing

描述（由申请人提供）： 难治性伤口是糖尿病患者的主要临床问题，常常导致截肢。近年来的研究表明，内皮祖细胞（endothelial progenitor cells，EPCs）作为成熟内皮细胞的前体细胞，在创伤修复中对局部血管生成有重要作用，为基于EPCs的细胞治疗糖尿病创伤提供了理论依据。然而，1型和2型糖尿病患者的EPC血管生成功能严重受损，直接限制了其临床自体细胞治疗的潜力。MicroRNA是一类新的内源性小分子非编码RNA，可能作为关键的转录后调节因子发挥其治疗潜力。在所有的miRNAs中，迄今为止，只有不到10种miRNAs被报道在成熟的内皮细胞中发挥促血管生成或抗血管生成作用。值得注意的是， 存在于EPC介导的血管生成的miRNA调节中，特别是在疾病条件下。这项竞争性的更新建议集中在促血管生成的microRNA mir-27 b上，因为我们的初步研究表明，它在糖尿病EPC中是缺乏的，它的恢复拯救了EPC 功能和加速糖尿病伤口愈合。这一迷人现象背后的机制尚不清楚。我们假设mir-27 b直接抑制新型促氧化剂ShcA蛋白p66 shc和/或有效的抗血管生成蛋白血小板反应蛋白-2（TSP-2），增加锰超氧化物歧化酶（MnSOD）和减少线粒体氧化应激，从而改善EPC血管生成功能并加速2型糖尿病的伤口愈合。这一假设是在仔细分析了 在上一个资助期内，我们的实验室在实地和生成一些关键的初步数据。我们计划通过追求三个具体目标来检验我们的中心假设并实现我们的目标。在目标1中，我们将确定mir-27 b如何改善糖尿病患者的EPC血管生成功能。在目的2中，我们将确定mir-27 b在糖尿病EPCs中的直接靶点。在目标3中，我们将检查mir-27 b靶向EPC细胞疗法对糖尿病伤口愈合的功能后果。本研究的主要意义在于首次揭示了miRNAs如何调控糖尿病患者EPC血管生成和伤口修复。确定促血管生成mir-27 b如何调节糖尿病EPC功能，可能会导致越来越多患有这种毁灭性并发症的糖尿病患者的难治性伤口的miRNA修饰改善自体EPC细胞治疗。

DESCRIPTION (provided by applicant): Refractory wound is a major clinical problem in diabetic patients that often leads to amputations. Recent studies including ours suggest that endothelial progenitor cells (EPCs), precursor of mature endothelial cells, critically contribute to local angiogenesis in wound repair, providing th proof of concept of EPC-based cell therapy for diabetic wounds. However, EPC angiogenic functions are severely impaired in both type 1 and type 2 diabetic patients, directly limiting thei potential for autologous cell therapies clinically. MicroRNAs are a new class of small endogenous non-coding RNAs that may exert their therapeutic potential as key post-transcriptional regulators. Among all miRNAs, less than 10 of them have been reported to exert pro- or anti-angiogenic effects in mature endothelial cells to date. Remarkably, little information exist on miRNA regulation of EPC-mediated angiogenesis, especially under disease conditions. This competitive renewal proposal focuses on pro-angiogenic microRNA mir-27b because our preliminary studies indicate that it is deficient in diabetic EPCs, and its restoration rescues EPC functions and accelerates diabetic wound healing. The mechanisms underlying this fascinating phenomenon remain unclear. We hypothesize that mir-27b directly suppresses a novel pro-oxidant ShcA protein p66shc and/or potent anti-angiogenic protein thrombospondin-2 (TSP-2), with increased manganese superoxide dismutase (MnSOD) and reduced mitochondrial oxidative stress that result in improved EPC angiogenic function and accelerated wound healing in type 2 diabetes. This hypothesis is formulated after a careful analysis of published work in the field and the generation of some key preliminary data in our laboratory during the last funding period. We plan to test our central hypothesis and accomplish our objective by pursuing three specific aims. In Aim 1, we will determine how mir-27b improves EPC angiogenic function in diabetes. In Aim 2, we will determine the direct target of mir-27b in diabetic EPCs. In Aim 3, we will examine the functional consequences of mir-27b targeted EPC cell therapy on wound healing in diabetes. The major significance of this study is that it will delineate for the first tme how miRNAs regulate EPC angiogenesis and wound repair in diabetes. Determine how diabetic EPC functions are regulated by pro-angiogenic mir-27b could lead to improved autologous EPC cell therapy with miRNA modification for refractory wounds in increasing number of diabetic patients who suffer from this devastating complication.