Mesenchymal stem cell-derived exosomes protect beta cells against hypoxia-induced apoptosis via miR-21 by alleviating ER stress and inhibiting p38 MAPK phosphorylation

作者：Jin Chen, Junqiu Chen, Yuanhang Cheng, Junqiu Chen, Yuanhang Cheng, Yunfeng Fu, Hu Zhao, Minying Tang, Hu Zhao, Na Lin, Xiaohua Shi, Yan Lei, Shuiliang Wang, Lianghu Huang, Weizhen Wu, Ming Jen Tan · 发表于：Stem Cell Research & Therapy · 年份：2020 · DOI：10.1186/s13287-020-01610-0 · 被引用次数：223 · 研究领域：Extracellular vesicles in disease、Mesenchymal stem cell research、Pancreatic function and diabetes

BACKGROUND: Hypoxia is a major cause of beta cell death and dysfunction after transplantation. The aim of this study was to investigate the effect of exosomes derived from mesenchymal stem cells (MSCs) on beta cells under hypoxic conditions and the potential underlying mechanisms. METHODS: Exosomes were isolated from the conditioned medium of human umbilical cord MSCs and identified by WB, NTA, and transmission electron microscopy. Beta cells (βTC-6) were cultured in serum-free medium in the presence or absence of exosomes under 2% oxygen conditions. Cell viability and apoptosis were analysed with a CCK-8 assay and a flow cytometry-based annexin V-FITC/PI apoptosis detection kit, respectively. Endoplasmic reticulum stress (ER stress) proteins and apoptosis-related proteins were detected by the WB method. MiRNAs contained in MSC exosomes were determined by Illumina HiSeq, and treatment with specific miRNA mimics or inhibitors of the most abundant miRNAs was used to reveal the underlying mechanism of exosomes. RESULTS: Exosomes derived from MSC-conditioned culture medium were 40-100 nm in diameter and expressed the exosome markers CD9, CD63, CD81, HSP70, and Flotillin 1, as well as the MSC markers CD73, CD90, and CD105. Hypoxia significantly induced beta cell apoptosis, while MSC exosomes remarkably improved beta cell survival. The WB results showed that ER stress-related proteins, including GRP78, GRP94, p-eIF2α and CHOP, and the apoptosis-related proteins cleaved caspase 3 an...