α7nAChR调节糖尿病伤口愈合的生物学机制研究

Impaired wound healing in diabetes featured inflammation dyregulation and delayed repair. Diabetic wound can appear acumulation of advanced glycation end-products (AGEs) , which increased generation of TNF-α in monocytes and macrophages. As a result, wound healing is delayed because excessive fibroblast apoptosis was induced by TNF-α. Our previous study demonstrated that activation of α7nAChR can promote wound healing by suppressing TNF-α expression and up-regulating the number of fibroblast in diabetic wound. Based on findings mentioned above, we speculate that α7nAChR can regulate persistent inflammation and excessive fibroblast apoptosis during wound healing in diabetes. In the present project, we expected to elucidate the roles of α7nAChR in diabetic wound healing. The content of present project will include as follows: 1) Establishing a model of skin incised wound in diabetic mice; 2) To detect that α7nAChR activation or inactivation exert effect on inflammation, fibroblast apoptosis and angiogenesis during wound healing in diabetes; 3) To culture the primary monocytes and fibroblasts; 4) To elucidate the role of α7nAChR in regulaing AGEs-induced proinflammatory reaction and TNF-α-induced fibroblast apoptosis; 5) To explore potential signaling cascade involved in α7nAChR regulation. In conclusion, the findings of our present project will provide new strategies for preventing and treating impaired wound healing in diabetic patients.

紊乱炎症反应伴修复迟滞是糖尿病伤口不愈的重要特征。糖尿病可出现糖基化终末产物（AGEs）蓄积于创面，致单核巨噬细胞持续释放TNF-α，诱导成纤维细胞过度凋亡阻碍伤口修复进程。前期工作示激活alpha7烟碱型乙酰胆碱受体（α7nAChR）可抑制糖尿病伤口中TNF-α的表达，上调成纤维细胞数量，促进伤口愈合。由此推测α7nAChR可调控糖尿病伤口愈合期间紊乱的炎症反应及其诱发的成纤维细胞凋亡。故本项目拟建立糖尿病小鼠切创模型，观察激活或抑制α7nAChR后对糖尿病伤口愈合期间炎症反应、成纤维细胞凋亡以及血管发生的影响；同时通过原代单核细胞和成纤维细胞培养，阐明α7nAChR对AGEs诱导的促炎反应、TNF-α诱导的成纤维细胞凋亡的调控作用，并深入探讨其细胞信号转导通路。本项目旨在明确α7nAChR对糖尿病伤口愈合的调控效应和作用环节，为拓展防治糖尿病伤口不愈提供一种新思路和药物作用新靶点。

糖尿病伤口可出现糖基化终末产物（AGEs）的蓄积、紊乱炎症反应及成纤维细胞过度凋亡，阻碍伤口修复。本研究在复制糖尿病伤口愈合模型的基础上，观察激活或抑制α7nAChR后对糖尿病伤口愈合期间炎症反应及成纤维细胞凋亡等事件的影响；并通过细胞培养技术探讨α7nAChR对AGEs诱导的促炎反应、TNF-α诱导的成纤维细胞凋亡的调控作用及机制。本研究显示糖尿病伤口愈合后期出现AGEs的过度蓄积及AGEs受体（RAGE）的表达上调，AGEs诱导了巨噬细胞的NF-κB激活、促炎介质产生及RAGE表达，而促炎介质TNF-α可诱导成纤维细胞凋亡。激活α7nAChR可以促进糖尿病伤口愈合，抑制AGEs诱导的NF-κB激活和促炎介质产生，并抑制TNF-α诱导的成纤维细胞凋亡，激活成纤维细胞中的Jak2-PI3K-AKT通路。研究结果表明α7nAChR可调控糖尿病伤口不愈的多个发病环节，有望成为防治糖尿病伤口不愈的新靶点。