缺氧预处理脐血MSCs通过外泌体调控扩张型心肌病心肌重塑的作用机制

In recent years, stem cell-derived exosomes have been found to be anti-apoptotic, anti-fibrotic and pro-angiogenic. As such, stem cell-derived exosomes are considered to be a potential novel approach in the treatment of cardiovascular diseases. However, the role of stem cell-derived exosomes on dilated cardiomyopathy(DCM) is still unclear. In addition, proportion of miRNAs within exosomes is considered to be much higher than the parent cells, and ischemic preconditioning of MSCs enhanced levels of miRNA-21 in exosomes. The effects of MSCs exosomes miRNA-21 in myocardial remodeling need to be further investigation. This study proposes the research hypothesis：Hypoxic preconditioning MSCs improve myocardial remodeling of DCM through exosomes. First of all, we chose the umbilical cord blood MSCs as the research object, to discuss the influence of hypoxia on MSCs exosomes; based on this, in vivo we study the effect of hypoxic preconditioning MSCs exosomes on cardiac function, apoptosis, autophagy and angiogenesis of cTnTR141W DCM mouse; in vitro, to further research the effect and potential mechanism of hypoxic preconditioning MSCs exosomes on apoptosis, autophagy and angiogenesis from a cellular level, as well as to explore the role of miRNA-21 play in. Through this study, we hope to make clear the efficacy of MSCs exosomes therapy on DCM, and to provide a novel approach and theoretical basis for future study of stem cell therapy on DCM.

新近发现干细胞外泌体具有抗心肌细胞凋亡、抗心肌纤维化及促进血管新生等作用，为治疗心血管疾病提供了新的思路，但其在扩张型心肌病（DCM）中的作用尚不清楚。此外间充质干细胞（MSCs）外泌体中含有大量miRNA，且缺氧预处理MSCs外泌体中的miRNA-21水平明显增加，其在心肌重塑中的作用缺乏研究。本研究提出经缺氧预处理的MSCs通过外泌体改善DCM心肌重塑的研究假设。首先以脐血MSCs为研究对象，探讨缺氧对MSCs外泌体的影响；在此基础上拟用cTnTR141W转基因小鼠DCM模型，探讨缺氧预处理MSCs外泌体对心功能的影响，以及对心肌细胞凋亡、血管新生和自噬调节的作用；体外实验在细胞层面进一步探讨缺氧预处理MSCs外泌体对凋亡、自噬及血管新生的作用及机制，并探讨miRNA-21在其中的作用。通过本研究明确MSCs外泌体对DCM的治疗作用，对今后干细胞治疗DCM提供新的思路及理论依据。

干细胞外泌体具有抗心肌细胞凋亡、抗心肌纤维化及促进血管新生等作用，为治疗心血管疾病提供了新的思路，但其在扩张型心肌病（DCM）中的作用尚不清楚。本研究提出经缺氧预处理的MSCs通过外泌体改善DCM心肌重塑的研究假设。首先以脐血MSCs为研究对象，探讨缺氧对MSCs外泌体的影响；在此基础上，体外实验在细胞层面探讨缺氧预处理MSCs外泌体对凋亡、自噬及血管新生的作用及机制。体内实验cTnTR141W转基因小鼠DCM模型，探讨脐血MSCs CM对心功能的影响，以及对心肌细胞凋亡、自噬调节的作用。研究表明，脐血MSCs外泌体可以通过调节 PI3K/Akt/mTOR，抑制心肌细胞凋亡、调节心肌细胞自噬。并且尾静脉注射脐血MSCs CM也可通过激活PI3K/Akt/mTOR 通路，抑制扩心病小鼠心肌细胞凋亡、调节自噬，从而改善扩心病小鼠的心脏结构及功能。研究也发现，缺氧预处理后，脐血MSCs CM的上述作用进一步增强。