Senescent cardiac fibroblasts-derived extracellular vesicles induced autophagy in cardiac fibroblasts via suppression of ras homolog enriched in brain like 1

Abstract

Cardiac fibroblasts (CFs) play roles in the maintenance of myocardial tissue structure. Cellular senescence is a state of stable cell cycle arrest. We previously reported that extracellular vesicles (EV) secreted by doxorubicin (DOX, 1000 nM)-induced senescent CFs (D10³-EV) caused autophagy in CFs. EV mediate cell-to-cell communication through the transfer of microRNA (miRNA). In this study, we focused on miRNA contained in EV and aimed to elucidate mechanisms underlying the autophagy induction by D10³-EV in CFs. Neonatal rat CFs (NRCFs) were treated with DOX for the induction of cellular senescence. EV were isolated from culture media of NRCFs. miRNA was extracted from the EV and miRNA profiles were analyzed using miRNA-seq. Seven miRNAs were significantly decreased, whereas 14 miRNAs were significantly increased in D10³-EV compared with the vehicle-treated NRCFs-derived EV. Among the target genes of 14 miRNAs, Rhebl1 was identified. D10³-EV significantly increased microtubule-associated protein 1 light chain 3 (LC3)-II/LC3-I and decreased protein expression of Ras homolog enriched in brain like 1 (RHEBL1) in NRCFs. Small interfering RNA against Rhebl1 tended to increase LC3-II/LC3-I. In conclusion, we for the first time revealed that the senescent NRCFs-derived EV induced autophagy in NRCFs via the suppression of RHEBL1 protein.