Fetal bovine serum-derived exosomes regulate the adipogenic differentiation of human bone marrow mesenchymal stromal cells in a cross-species manner.

Fetal bovine serum (FBS) contains a large number of exosomes which may disturb the analysis of exosomes derived from cultured cells. We investigated the effect of FBS-derived exosomes (FBS-Exos) on the adipogenic differentiation of human bone marrow mesenchymal stromal cells (hBM-MSCs) and the underlying molecular mechanism. The uptake of FBS-Exos by hBM-MSCs could be detected by the laser confocal microscopy, and the treatment of exosomes resulted in the decreased lipid droplet formation and reduced expression of genes associated with adipogenic differentiation of hBM-MSCs. miR-1246 was identified as an abundant microRNA in FBS-Exos by public sequencing data identification and RT-qPCR validation. Moreover, miR-1246 overexpression in hBM-MSCs led to decreased adipogenic differentiation level, while miR-1246 knockdown in FBS-Exos attenuated the inhibitory effect on the adipogenic differentiation. Our results indicate that FBS-Exos inhibit the adipogenic differentiation of hBM-MSCs in a cross-species manner and miR-1246 transferred by FBS-Exos partly contributes to this effect.