Trophoblast Stem-Cell-Derived Exosomes Improve Doxorubicin-Induced Dilated Cardiomyopathy by Modulating the let-7i/YAP Pathway.

Trophoblast stem cells (TSCs) have been confirmed to play a cardioprotective role in heart failure. However, whether TSC-derived exosomes (TSC-exos) can protect against cardiac injury remains unclear. In the present study, TSC-exos were isolated from the supernatant of TSCs using the ultracentrifugation method and characterized by transmission electron microscopy and western blotting. Utilizing the public Gene Expression Omnibus (GEO) database, we found that let-7i and Yes-associated protein 1 (YAP) could participate in the development of heart failure. In vitro, AC16 cardiomyocytes subjected to doxorubicin (DOX) were treated with TSC-exos or let-7i mimic. Flow cytometry showed that TSC-exos and let-7i both decreased cardiomyocyte apoptosis. In vivo, mice that were intraperitoneally injected into DOX received either PBS, TSC-exos, or AAV9-let7iup for let-7i overexpression. Mice receiving TSC-exos and AAV9-let7iup showed improved cardiac function and decreased inflammatory responses, accompanied by downregulated YAP signaling. Mechanistically, TSC-exos could transfer let-7i to cardiomyocytes and silence the YAP signaling pathway. In conclusion, TSC-exos could alleviate DOX-induced cardiac injury via the let-7i/YAP pathway, which sheds new light on the application of TSC-exos as a potential therapeutic tool for heart failure.