Huashan Hospital, Fudan University, Shanghai, China.
Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Curr Pharm Des. 2018;24(44):5334-5341. doi: 10.2174/1381612825666190119130441.
Human mesenchymal stem cell-derived exosomes (hMSC-Exo) have been shown to reduce ischemia/reperfusion injury (I/R) in multiple models. I/R-induced apoptosis or autophagy play important roles in cell death. However, little or no reports demonstrate any roles of hMSC-Exo in this regards.
To test the hypothesis that the inhibition of I/R-induced apoptosis and autophagy play a pivotal role in the cardioprotection of hMSC-Exo.
Myoblast H9c2 cells and isolated rat hearts underwent hypoxia/re-oxygenate (H/R) or ischemia/ reperfusion (I/R) respectively. H9c2 were treated with 1.0 μg/ml Exo, in comparison with 3-MA or rapamycin (Rapa), a known anti- or pro-autophagic agent respectively. Hearts were treated with 0.5, 1.0 and 2.0 μg/ml Exo for 20 min in the beginning of reperfusion. Cell viability, WST assay, LDH release, Annexin-V staining apoptosis assay and GFP-LC3 labeled autophagosomes formation, cardiac function and Western blot were measured.
Exo significantly reduced H/R injury as indicated by increased cell viability and reduced LDH and apoptosis. 3-MA, while Rapa, showed increased or decreased protective effects. Rapa-induced injury was partially blocked by Exo. Exo decreased LC3-II/I ratio and increased p62, inhibited autophagosome formation, an indication of autophagy inhibition. In isolated heart, Exo increased cardiac functional recovery and reduced LDH release in I/R. Bcl-2 was significantly upregulated by Exo but not 3-MA. Exo downregulated Traf6 and upregulated mTORC1/p-4eBP1.
Exo reduce I/R-induced apoptosis and autophagy. Up-regulation of Bcl-2 is the cross-talk between these two processes. The down-regulation of Traf6 and activation of mTORC1 are additional mechanisms in the inhibition of apoptosis and autophagy.
人骨髓间充质干细胞衍生的外泌体（hMSC-Exo）已被证明可减少多种模型中的缺血/再灌注损伤（I/R）。I/R 诱导的细胞凋亡或自噬在细胞死亡中起重要作用。然而，几乎没有或没有报道表明 hMSC-Exo 在这方面有任何作用。
验证抑制 I/R 诱导的细胞凋亡和自噬在 hMSC-Exo 的心脏保护中起关键作用的假说。
肌母细胞 H9c2 细胞和分离的大鼠心脏分别经历缺氧/复氧（H/R）或缺血/再灌注（I/R）。H9c2 用 1.0μg/ml 的外泌体处理，与 3-MA 或雷帕霉素（Rapa）比较，后者分别是已知的抗或促进自噬的药物。心脏在再灌注开始时用 0.5、1.0 和 2.0μg/ml 的外泌体处理 20 分钟。用 WST 法、LDH 释放、Annexin-V 染色凋亡测定和 GFP-LC3 标记的自噬体形成、心脏功能和 Western blot 测定来测量细胞活力、细胞活力、LDH 释放、Annexin-V 染色凋亡测定和 GFP-LC3 标记的自噬体形成、心脏功能和 Western blot 测定来测量细胞活力。
外泌体显著减少 H/R 损伤，表现为细胞活力增加和 LDH 和凋亡减少。3-MA 虽然 Rapa 表现出增加或减少的保护作用。Rapa 诱导的损伤部分被外泌体阻断。外泌体降低 LC3-II/I 比值并增加 p62，抑制自噬体形成，表明自噬抑制。在分离的心脏中，外泌体增加了心脏功能的恢复并减少了 I/R 中的 LDH 释放。外泌体显著上调 Bcl-2，但不上调 3-MA。外泌体下调 Traf6 并上调 mTORC1/p-4eBP1。
外泌体减少 I/R 诱导的细胞凋亡和自噬。Bcl-2 的上调是这两个过程之间的交叉对话。Traf6 的下调和 mTORC1 的激活是抑制凋亡和自噬的其他机制。
