间充质干细胞源性外泌体HSP70促进皮肤表皮伤口愈合的机制研究

The degree of apoptosis of keratinocytes plays an important role in skin wound healing. Previous experiments have found that centrifugal purified umbilical cord mesenchymal stem cell exosomes (hUCMSCs-Ex) can significantly promote the healing of skin wounds on the back of diabetic mice, but the molecular and mechanism of key proteins in Ex that play a role in promoting epidermal wound healing remains unclear. In the previous experiment, mass spectrometry analysis showed that Ex was rich in HSP70, one of the heat shock proteins. HSP70 can regulate caspase-dependent Apaf1 and AIF in the apoptosis pathway of PARP/1-AIF and inhibit apoptosis. Accordingly, the applicant proposed the hypothesis that "HSP70 in Ex regulates PARP-1/AIF signaling pathway, inhibits keratinocytes apoptosis, and thereby promotes epidermal wound healing". The purpose of this study was to obtain hUCMSCs-Ex by ultra-high speed gradient centrifugation combined with the purification kit. In vitro keratinocytes apoptosis and in vivo skin injury models, cell and molecular intervention techniques were applied to verify the key molecules and mechanism of hUCMSCs-Ex in promoting skin epidermal regeneration and healing in the treatment of skin trauma，It provides a certain theoretical basis for the treatment of prolonged non-healing wounds.

角质形成细胞的凋亡程度在皮肤伤口愈合过程中具有重要的影响。前期实验发现：离心纯化的脐带间充质干细胞外泌体（hUCMSCs-Ex）可以显著促进糖尿病小鼠背部皮肤伤口愈合，但Ex中起到表皮伤口促愈作用的关键蛋白分子及机制尚不清楚。在前期实验中通过质谱分析发现Ex中含有丰富的热休克蛋白之一HSP70。HSP70可以调控caspase依赖及PARP/1-AIF凋亡通路中的Apaf1及AIF，抑制细胞凋亡。据此，申请人提出“是否是Ex中的HSP70调控PARP-1/AIF信号通路，抑制角质形成细胞凋亡，进而促进表皮伤口愈合”的假说。本研究旨在利用超高速梯度离心结合试剂盒纯化，获得hUCMSCs-Ex；在体外角质形成细胞凋亡和体内皮肤损伤模型中应用细胞与分子干预技术予以验证，确定hUCMSCs-Ex在治疗皮肤创伤中促进皮肤表皮再生愈合的关键分子及其作用机制，为经久不愈性伤口的治疗提供一定的理论基础。