Exosome-Mediated miRNA Delivery Restores Early Differentiation and Survival Programs in DGCR8-Deficient Mouse...

Pluripotent stem cell (PSC) differentiation is orchestrated by intricate autocrine and paracrine signaling networks. Among these, exosomes, key components of the cellular secretome, are implicated as crucial mediators of intercellular communication via delivery of bioactive molecules, including microRNAs (miRNAs). This study investigated the role of exosomal miRNAs in stem cell differentiation using Dgcr8-deficient mouse embryonic stem cells (mESCs), which are incapable of producing mature miRNAs. Although the differentiation capacity was markedly impaired in these cells, partial restoration was observed following treatment with exosomes derived from differentiating wild-type mESCs. Exosomal miRNA uptake was confirmed, and gene ontology analysis revealed significant enrichment of pathways associated with cell fate determination, morphogenesis, and apoptosis regulation. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that exosomal miRNAs modulated multiple osteoinductive signaling cascades, notably the MAPK and TGF-β pathways, in Dgcr8-deficient cells. Apoptotic markers were also downregulated, suggesting a protective effect conferred by the exosomal cargo. Collectively, our results suggest that exosome-mediated delivery of miRNAs may represent a fundamental mechanism by which pluripotent stem cells coordinate stress responses and differentiation trajectories, providing novel insights into the regulation of embryogenesis.