移植间充质干细胞通过外泌体转移 miR-125b 减少梗死心脏中的自噬通量。

Transplanted Mesenchymal Stem Cells Reduce Autophagic Flux in Infarcted Hearts via the Exosomal Transfer of miR-125b.

机构信息

From the Department of Cardiology, Second Affiliated Hospital, College of Medicine (C.X., K.W., Y.X., H.H., N.Z., Y.W., Z.Z., J.Z., Q.L., D.Z., C.K., S.Z., X.W., H.Y., W.Z., J.C., J.W., X.H.).

Zhejiang University, Hangzhou, China; Cardiovascular Key Laboratory of Zhejiang Province, Hangzhou, China (C.X., K.W., Y.X., H.H., N.Z., Y.W., Z.Z., J.Z., Q.L., D.Z., C.K., S.Z., X.W., H.Y., W.Z., J.C., J.W., X.H.).

出版信息

Circ Res. 2018 Aug 17;123(5):564-578. doi: 10.1161/CIRCRESAHA.118.312758.

DOI:10.1161/CIRCRESAHA.118.312758

PMID:29921652

Abstract

RATIONALE

Autophagy can preserve cell viability under conditions of mild ischemic stress by degrading damaged organelles for ATP production, but under conditions of severe ischemia, it can promote cell death and worsen cardiac performance. Mesenchymal stem cells (MSCs) are cardioprotective when tested in animal models of myocardial infarction, but whether these benefits occur through the regulation of autophagy is unknown.

OBJECTIVE

To determine whether transplanted MSCs reduce the rate of autophagic degradation (autophagic flux) in infarcted hearts and if so, to characterize the mechanisms involved.

METHODS AND RESULTS

Treatment with transplanted MSCs improved cardiac function and infarct size while reducing apoptosis and measures of autophagic flux (bafilomycin A1-induced LC3-II [microtubule-associated protein 1 light chain 3] accumulation and autophagosome/autolysosome prevalence) in infarcted mouse hearts. In hypoxia and serum deprivation-cultured neonatal mouse cardiomyocytes, autophagic flux and cell death, as well as p53-Bnip3 (B-cell lymphoma 2-interacting protein 3) signaling, declined when the cells were cultured with MSCs or MSC-secreted exosomes (MSC-exo), but the changes associated with MSC-exo were largely abolished by pretreatment with the exosomal inhibitor GW4869. Furthermore, a mimic of the exosomal oligonucleotide miR-125b reduced, whereas an anti-miR-125b oligonucleotide increased, autophagic flux and cell death, via modulating p53-Bnip3 signaling in hypoxia and serum deprivation-cultured neonatal mouse cardiomyocytes. In the in vivo mouse myocardial infarction model, MSC-exo, but not the exosomes obtained from MSCs pretreated with the anti-miR-125b oligonucleotide (MSC-exo), recapitulated the same results as the in vitro experiments. Moreover, measurements of infarct size and cardiac function were significantly better in groups that were treated with MSC-exo than the MSC-exo group.

CONCLUSIONS

The beneficial effects offered by MSC transplantation after myocardial infarction are at least partially because of improved autophagic flux through excreted exosome containing mainly miR-125b-5p.

摘要

背景

自噬可以通过降解受损细胞器产生 ATP 来维持轻度缺血应激条件下的细胞活力，但在严重缺血条件下，自噬会促进细胞死亡并恶化心脏功能。间充质干细胞（MSCs）在心肌梗死动物模型中具有心脏保护作用，但这些益处是否通过自噬调节尚不清楚。

目的

确定移植的 MSCs 是否会降低梗死心脏中的自噬降解率（自噬流），如果是，那么确定其涉及的机制。

方法和结果

用移植的 MSCs 治疗可改善心脏功能和梗死面积，同时减少细胞凋亡和自噬流的测量值（巴弗洛霉素 A1 诱导的 LC3-II[微管相关蛋白 1 轻链 3]积累和自噬体/自溶体出现）在梗死的小鼠心脏中。在缺氧和血清剥夺培养的新生小鼠心肌细胞中，当细胞与 MSC 或 MSC 分泌的外泌体（MSC-exo）共培养时，自噬流和细胞死亡以及 p53-Bnip3（B 细胞淋巴瘤 2 相互作用蛋白 3）信号均下降，但与 MSC-exo 相关的变化在预处理用外泌体抑制剂 GW4869 后大部分被消除。此外，外泌体寡核苷酸 miR-125b 的模拟物通过调节缺氧和血清剥夺培养的新生小鼠心肌细胞中的 p53-Bnip3 信号，降低了自噬流和细胞死亡，而抗 miR-125b 寡核苷酸则增加了自噬流和细胞死亡。在体内小鼠心肌梗死模型中，MSC-exo 但不是用抗 miR-125b 寡核苷酸预处理的 MSC 获得的外泌体（MSC-exo），再现了与体外实验相同的结果。此外，与 MSC-exo 组相比，用 MSC-exo 治疗的组的梗死面积和心脏功能的测量值明显更好。