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.

胎牛血清 (FBS) 含有大量外泌体，可能会干扰对培养细胞来源的外泌体的分析。我们研究了 FBS 衍生的外泌体 (FBS-Exos) 对人骨髓间充质基质细胞 (hBM-MSC) 成脂分化的影响和潜在的分子机制。hBM-MSCs 对 FBS-Exos 的摄取可以通过激光共聚焦显微镜检测到，外泌体的处理导致脂滴形成减少和与 hBM-MSCs 成脂分化相关的基因表达减少。通过公共测序数据鉴定和 RT-qPCR 验证，miR-1246 被鉴定为 FBS-Exos 中丰富的 microRNA。此外，hBM-MSCs 中 miR-1246 的过表达导致成脂分化水平降低，而 FBS-Exos 中的 miR-1246 敲低减弱了对成脂分化的抑制作用。我们的结果表明，FBS-Exos 以跨物种的方式抑制 hBM-MSC 的脂肪形成分化，而 FBS-Exos 转移的 miR-1246 部分促成了这种作用。