Figure 4. Exosomal miRNAs are implicated in hUMSC-Exos-mediated attenuation of microglial pro-inflammatory activity. (A, B) After 24 hours’ siRNA-Drosha transfection, hUMSC Drosha knockdown efficiency was evaluated by qPCR quantitation of Drosha mRNA and western blot-based quantitation of Drosha protein. Western blots are representative of three independent experimental replicates. (C, D) Exosomal miR-146a-5p and miR-21-5p content was significantly decreased after Drosha knockdown. (E) Protein levels of the pro-inflammatory cytokines IL-6, TNF-α, and IL-1β in hUMSC-Exos were decreased after Drosha knockdown. (F) Detection of IL-6, TNF-α, and IL-1β mRNA levels via qRT-PCR. Data are expressed as mean ± SEM. (A-F) Each experiment is representative of n = 3 per group. Significant differences are indicated (*p < 0.05, **p < 0.01).