Lipopolysaccharide-stimulated bone marrow mesenchymal stem cells-derived exosomes inhibit H2O2-induced cardiomyocyte inflammation and oxidative stress via regulating miR-181a-5p/ATF2 axis

OBJECTIVE: Myocardial infarction (MI) is a cardiovascular disease that seriously endangers human health. Exosomes secreted by stem cells have big potential for the treatment of many diseases. The purpose of this study was to study the therapeutic effects of exosomes derived from lipopolysaccharide (LPS)-stimulated bone marrow mesenchymal stem cells (BMSCs) on MI. PATIENTS AND METHODS: The surface markers of BMSCs were detected by Western blot. After BMSCs were stimulated with LPS for 2 days, the exosomes secreted by BMSCs were extracted and observed by transmission electron microscopy (TEM), and their specific surface markers were detected by Western blot. H9c2 cells were co-cultured with exosomes for 24 hours, and then, treated with H202 for 4 hours. Next, H9c2 cells were transfected with miRNA-181a-5p mimic (MIM) or negative control (NC). Inflammation and oxidative stress of H9c2 cells were detected by Western blot, cell staining, reactive oxygen species (ROS) quantification. and SOD activity assay. At last, miR-181a-5p expression in BMSCs, exosomes, and H9c2 cells was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). RESULTS: The results revealed that the expression of miR-181a-5p was increased in LPS-stimulated BMSCs (L-BMSC) and in their secreted exosomes. Besides, the expressions of TNF-alpha and IL-1 beta were decreased, while those of SOD1 and SOD2 were increased in H9c2 cells co-cultured with exosomes secreted by LPS-stimulated BMSCs (L-EXO) and transfected with MIM. Moreover, the fluorescence intensity of IL-1 beta immunofluorescence was decreased in H9c2 cells co-cultured with L-EXO or transfected with MIM. The level of ROS was also decreased in H9c2 cells co-cultured with L-EXO or transfected with MIM. Furthermore, miR-181a-5p was found to target ATF2 through target gene prediction databases and Western blot and Dual-Luciferase reporter assays. CONCLUSIONS: LPS stimulation can increase the expression of miR-181a-5p in BMSCs, and miR-181a-5p inhibits myocardial inflammation and oxidative stress by targeting ATF2.