miR-21-5p 靶向 TET2 调控 DNA去甲基化在复方积雪草生肌凝胶剂促进糖尿病皮肤创伤愈合中的作用及分子机制

糖尿病足溃疡（DFU）创面难愈机制尚不完全清楚。前期课题组将积雪草与NO组方出积雪草生肌凝胶剂（CACMG），发现CACMG可促进DFU创面愈合、血管新生、上调miR-21-5p，但其分子机制尚不清楚。继而我们通过生信分析发现miR-21-5p下游靶向调控TET2等DNA去甲基化基因，同时发现，TET2在病人成纤维及角质细胞中表达，提示TET2可能在表皮及毛囊干细胞动员与维持中发挥了作用；因此我们推测miR-21-5p可能通过靶向TET2介导的DNA去甲基化途径而促进DFU创伤愈合。本课题将采用miRNA-21-/-全身敲除小鼠，在体内外过表达/敲减方法验证其是否通过靶向TET2调控DNA去甲基化路径而参与创伤修复过程；从非编码RNA及DNA甲基化的角度揭示miR-21-5p在CACMG促进DFU创伤修复过程中发挥作用的分子机制，为临床DFU皮肤创伤的诊治提供新的候选靶点和理论依据。

Diabetic foot ulcers (DFU) are a major health-care burden worldwide. However, the mechanism causing this dysfunction is not fully understood. miRNAs are highly conserved endogenous small noncoding RNA molecules involved in numerous biological processes including diabetic wound healing. However, their function in diabetic wound healing is unclear..Supported by the NSFC, we innovatively combined Centella asiatica with NO, which can not only promote wound healing, but also inhibit scar formation, and has good biocompatibility and degradability. Centella asiatica compound myogenic gel (CACMG) was created, which not only guaranteed the superposition effect, but also made NO release slowly. It was found that CACMG could promote the repair and healing of DFU wounds, promote angiogenesis, up-regulate miR-21-5p and so on. However, the role, function and regulation mechanism of miR-21-5p in the treatment of DFU trauma by CACMG need to be elucidated. .There is evidence that DNA demethylation plays an active role in DFU wound healing. We have previously found that miR-21-5p downstream targeted TET1,TET2 and other DNA demethylation genes through bioinformatics analysis. At the same time, it was found that TET2 was expressed in epidermal fibroblasts and keratinocytes of diabetic patients, suggesting that TET2 may play a role in the mobilization and maintenance of epidermal stem cells and hair follicle stem cells. Therefore, we speculate that miR-21-5p may promote DFU wound healing by targeting TET2-mediated DNA demethylation pathway. .In this study, miRNA-21-/- gene knockout mice and overexpression or knockdown methods in vitro were used to verify whether DNA demethylation was involved in the completion of wound repair by targeting combined with TET2. From the epigenetic point of view of non-coding RNA and DNA methylation, this study will reveal the key molecular mechanism of the role of miR-21-5p in the promotion of DFU skin wound repair by CACMG. It provides therapeutic targets and strategies to ameliorate complications from diabetic wounds of DFU.