尿源性iPSCs-MSCs外泌体结合活性复合水凝胶促进心肌再生修复的作用与机制

Stem cells transplantation therapy is beneficial to acute myocardial infarction（AMI）both in animals and clinical studies, but is restrained by the low survival rate of transplanted MSCs, genetic variation, aggravation of stenosis and safety issue. Exosomes derived from stem cells can avoid these deficiencies and exhibit the similar therapeutic effects on impaired cardiomyocytes to that of iPSCs, which possess better prospective for in clinic. In the early-stage work, we have successfully acquired iPSCs from renal epithelial cells in human urine by reprogramming technology. We also developed a new kind of alginate hydrogel aimed to solve the problems of current delivery system with low homing rate and easily to be affected by micro-environment of myocardial infarction. The novel hydrogel was beneficial to the promotion of stem cell differentiation, wound healing and angiogenesis. In this research, we will firstly induce the iPSCs to differentiate into mesenchymal stem cells and generate exosomes from MSCs and then investigate the effect and mechanism of MSCs derived exosomes combined with the novel alginate hydrogel in acute myocardial infarction injury. By using molecular biology and bioinformatics analysis methods, we aimed to explore the key targets and possible signal pathways which may provide a non-cell-based approach for AMI therapy.

干细胞在动物及临床上均对心肌梗死（AMI）具有非常明显的疗效，但存在移植存活率低、遗传变异、加重狭窄及致瘤致畸等不足使得其临床应用受到限制。干细胞旁分泌的活性成分外泌体（exosomes）能修复损伤心肌，同时又能避免上述不足，更具有临床应用前景。课题组前期已成功将尿源性肾上皮细胞重编程得到iPSCs，并针对现有的exosomes输注策略存在的归巢率低，受微环境影响大等不足，研制出一种能募集干细胞并促进分化、组织修复以及血管新生的活性海藻酸复合水凝胶。本项目拟进一步将尿源性iPSCs定向分化为间充质干细胞（MSCs）、并获得能满足临床前试验质量标准的MSCs-exosomes；在大鼠AMI模型中探讨MSCs-exosomes结合活性海藻酸复合水凝胶对AMI受损心肌的修复作用，寻找其发挥作用的关键靶点及分子通路，为AMI 的治疗提供一个可供选择的基于iPSCs-MSCs 的非细胞疗法和新思路。

本项目按计划完成了具有良好的生物相容性、一定程度的表面粗糙性及MMP-2酶切降解特性的AuNP-HA水凝胶，利用水凝胶高度仿生性和一定的表面粗糙度提高hiPS-CM体内滞留率和电活动整合力，进而优化其治疗心肌梗死的效能。体外研究发现，AuNP-HA水凝胶通过激活Integrin/ILK1/p-AKT通路促进hiPS-CM细胞缝隙连接的形成并增加其钙瞬变活性；体内研究发现，AuNP-HA水凝胶提升了hiPS-CM细胞的体内存活力及缝隙连接形成率，从而改善了心梗小鼠心室肌传导阻滞并增加了新生血管数量，最终使hiPS-CM对小鼠心肌梗死的治疗效果进一步得到提升。