GATA4-overexpressing BMSCs-derived exosome regulation of myocardial infarction in mice by key miRNA and apoptosis gene CLU.

BACKGROUND: Myocardial infarction (MI) is the most common cardiovascular disease that has a serious impact on human health and is one of the most common causes of death in the world. Apoptosis and myocardial fibrosis after MI are the key pathological features of poor myocardial remodelling, which further lead to heart failure, and are also the main reason for the high mortality from MI. METHODS: Exosomes (Exos) from GATA4-overexpressing bone marrow mesenchymal stem cells (BMSCs) were extracted and identified using transmission electron microscopy (TEM), nanoscale tracking analysis (NTA), and marker detection. Tandem mass tags (TMT) quantitative proteomics, Agilent miRNA microarray, and GO/KEGG function analysis were used to obtain differentially expressed proteins/miRNAs. The expression levels using the Wald test and RT-qPCR to identify and validate. Their related mRNA-miRNA-circRNA regulatory networks were constructed. Hypoxic mouse cardiomyocytes were cultured, and MI mice were used for subsequent experiments. Cell differentiation, apoptosis, and marker gene expression were detected using RT-qPCR, IF, flow cytometry, and Western blot. RESULTS: Four key apoptosis proteins, CXCL12, CLU, CD44, and IGF1, and 20 key differentially expressed miRNAs. Among them, CLU and IGF1 were upregulated, but CXCL12 and CD44 were downregulated in Exos from the GATA4-overexpressing BMSCs group. The expression of mmu-miR-467 g and mmu-miR-5127 was downregulated in Exos from the GATA4-overexpressing BMSCs group, whereas the other 18 key miRNAs were upregulated. Exos from GATA4-overexpressing BMSCs inhibit apoptosis, activate the LXR/RXR pathway, and improve MI. Knockout of CLU reversed this effect. Our research further discovered that GATA4-overexpressing BMSCs-derived Exos improved MI through downregulation of CLU. CONCLUSIONS: GATA4-overexpressing BMSCs-derived Exos may regulate MI via the aforementioned four key proteins and may be related to the LXR/RXR signalling pathway.