Recent studies demonstrated that circular RNAs play important roles in exosome-mediated cardio-protective effects after acute myocardial infarction (AMI). A previous study reported that circ_0001747 level is down-regulated in mouse hypoxia/reoxygenation (H/R) injury model. However, its biological role and working mechanism in AMI remain largely unknown.Exosomes were isolated from the culture supernatant of adipose-derived stem cells (ADSCs) using an ExoQuick precipitation kit. We treated mouse myocardial cells HL-1 with H/R to explore the role of exosomal circ_0001747 in AMI pathology. Cell viability, proliferation, apoptosis, and inflammation were analyzed by Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, and enzyme-linked immunosorbent assay. Dual-luciferase reporter assay and RNA immunoprecipitation assay were conducted to confirm the interaction between microRNA-199b-3p (miR-199b-3p) and circ_0001747 or MCL1 apoptosis regulator, BCL2 family member (MCL1).H/R-induced HL-1 dysfunction was attenuated by the incubation of exosomes derived from ADSCs, especially the exosomes with high amounts of circ_0001747. Circ_0001747 directly targeted miR-199b-3p in HL-1 cells. miR-199b-3p overexpression partly overturned exosomal circ_0001747-mediated protective effects in H/R-induced HL-1 cells. MCL1 was a direct target of miR-199b-3p in HL-1 cells. miR-199b-3p silencing alleviated H/R-induced damage in HL-1 cells partly by up-regulating MCL1. Circ_0001747 can elevate the messenger RNA and protein levels of MCL1 by sequestering miR-199b-3p.Overall, these results indicated that ADSCs-derived exosomes with high amounts of circ_0001747 attenuated H/R-induced HL-1 dysfunction partly by targeting miR-199b-3p/MCL1 signaling.
Keywords: Acute myocardial infarction; Apoptosis; Inflammation; Proliferation; Viability.