Synergistic reversal of mesenchymal stem cell senescence by engineered exosomal delivery of a dual miR-195/miR-188 sponge

BACKGROUND: Cellular senescence critically impairs the regenerative potential and therapeutic efficacy of adipose-derived mesenchymal stem cells (AD-MSCs). MicroRNAs miR-195 and miR-188 are key regulators of aging-associated pathways, making them attractive nucleic acid targets for senescence modulation. In this study, exosomes derived from Wharton's jelly mesenchymal stem cells (WJ-MSCs) were engineered to deliver a dual miR-195/miR-188 sponge. METHODS: Quantitative RT-PCR analysis confirmed that sponge-loaded exosomes significantly reduced intracellular levels of miR-195 and miR-188, demonstrating effective functional sequestration. Exosomes were characterized by dynamic light scattering, electron microscopy, and western blotting. Functional assays demonstrated efficient intracellular delivery and a robust reversal of senescence-associated phenotypes in replicative senescent AD-MSCs. RESULTS: Treatment significantly reduced senescence markers, including p16, p53, NF-κB, IL-6, and RB, while decreasing reactive oxygen species levels and β-galactosidase activity. Suppression of miR-195/miR-188 was associated with the restoration of the telomere length and reactivation of stemness-associated genes (SOX2, OCT4), suggesting modulation of telomere maintenance and cell-cycle regulatory pathways, including p53-RB signaling. Clonogenic capacity and cellular viability were markedly enhanced. CONCLUSION: In conclusion, exosome-mediated delivery of a dual miRNA sponge represents a mechanism-driven strategy to reprogram senescence-associated gene networks and restore MSC function. This approach provides a promising cell-free nucleic acid therapeutic platform for regenerative medicine applications.