Human trophoblast-derived exosomes attenuate doxorubicin-induced cardiac injury by regulating miR-200b and downstream Zeb1.

Human trophoblast stem cells (TSCs) have been confirmed to play a cardioprotective role in heart failure. However, whether trophoblast stem cell-derived exosomes (TSC-Exos) can protect cardiomyocytes from doxorubicin (Dox)-induced injury remains unclear. In the present study, TSC-Exos were isolated from the supernatants of human trophoblasts using the ultracentrifugation method and characterized by transmission electron microscopy and western blotting. In vitro, primary cardiomyocytes were subjected to Dox and treated with TSC-Exos, miR-200b mimic or miR-200b inhibitor. Cellular apoptosis was observed by flow cytometry and immunoblotting. In vivo, mice were intraperitoneally injected into Dox to establish a heart failure model. Then, different groups of mice were administered either PBS, adeno-associated virus (AAV)-vector, AAV-miR-200b-inhibitor or TSC-Exos via tail vein injection. Then, the cardiac function, cardiac fibrosis and cardiomyocyte apoptosis in each group were evaluated, and the downstream molecular mechanism was explored. TSC-Exos and miR-200b inhibitor both decreased primary cardiomyocyte apoptosis. Similarly, mice receiving TSC-Exos and AAV-miR-200b inhibitor exhibited improved cardiac function, accompanied by reduced apoptosis and inflammation. The bioinformatic prediction and luciferase reporter results confirmed that Zeb1 was a downstream target of miR-200b and had an antiapoptotic effect. TSC-Exos attenuated doxorubicin-induced cardiac injury by playing antiapoptotic and anti-inflammatory roles. The underlying mechanism could be an increase in Zeb1 expression by the inhibition of miR-200b expression. In summary, this study sheds new light on the application of TSC-Exos as a potential therapeutic tool for heart failure.