常温机械灌注器官保存系统加入MSCs外泌体通过抑制NLRP3介导的细胞焦亡而保护供体心脏的作用和机制研究

使用心死亡（DCD）心脏可扩大心脏移植中供体心脏的来源，但DCD心脏遭受严重的缺血再灌注损伤（IRI），降低心脏移植的成功率。最新研究表明，常温机械灌注器官保存（NMP）技术可减轻供体器官IRI，并提供修复供体器官的生物平台；间充质干细胞的外泌体（MSCs-exos）亦可减轻器官IRI。然而，在NMP系统加入MSCs-exos减轻DCD心脏IRI的作用和机制均不清楚。申请人自主研制了大鼠NMP系统，预实验发现：NLRP3介导的细胞焦亡参与心脏移植中DCD心脏IRI；MSCs-exos通过miRNA-486-3p下调TLR4/NLRP3焦亡信号通路。因此我们假设：NMP联合MSCs-exos可通过miRNA-486-3p抑制TLR4/NLRP3介导的细胞焦亡，从而减轻DCD心脏IRI。本课题采用体内外实验证实该假设，为该新型器官保存技术在DCD心脏保存的基础研究和临床转化提供创新理论。

In heart transplantation, the adoption of donor hearts from donation after circulatory death (DCD) is considered to be a promising approach to expanding the donor pool. However, DCD hearts inevitably suffer from severe myocardial ischemia/reperfusion injury (IRI), thereby reducing the successful rate of heart transplantation. Recent studies have shown that as a novel preservation strategy, normothermic machine perfusion (NMP) alleviates the IRI of donor organs and offers a unique platform to repair donor organs. Moreover, mesenchymal stem cells-derived exosomes (MSCs-exos) can ameliorate the IRI of organs. However, no relevant studies have investigated the cardioprotective effect and molecular mechanism of MSCs-exos added in the NMP in alleviating myocardial IRI for DCD hearts. Therefore, we firstly developed a novel rat NMP system. Our preliminary experiments demonstrated that NLRP3 inflammasome-mediated pyroptosis was involved in myocardial IRI of DCD hearts in heart transplantation. Besides, miRNA-486-3p in the MSCs-exos could inhibit TLR4/NLRP3-mediated pyroptosis. Consequently, we hypothesize that NMP combined with MSCs-exos can inhibit TLR4/NLRP3-mediated pyrolysis via miRNA-486-3p, thereby alleviating myocardial IRI for DCD hearts. In the current project, we will verify this hypothesis by performing pressure-volume catheters, immunofluorescence, and other techniques in the in vitro and in vivo models. This project will reveal the novel mechanism of NMP combined with MSCs-exos in reducing myocardial IRI for DCD hearts, and provide an innovative theory for the basic research and clinical transformation of this novel DCD hearts preservation technology.