Drosha regulates adipogenesis by modulating miR-204/miR-15b in OP9 cells

Mesenchymal stem cells (MSCs), being multipotent progenitors, have received the most widespread regulatory approval for commercialization as off-the-shelf cell therapies. Understanding the key molecular mechanisms regulating MSC differentiation is crucial for advancing their clinical utilization. Drosha is a critical enzyme in miRNA biogenesis. Despite its established role in diverse physiological processes, the involvement of Drosha in the adipogenic differentiation of MSCs has not been previously characterized. Here the role of Drosha/microRNA pathway in regulating the adipogenesis of OP9, a MSC derived from mouse bone marrow stroma, is characterized. Knocking down Drosha in OP9 significantly reduced its adipogenic capacity. Small RNA-seq analysis revealed that miR-204 and miR-15b were significantly downregulated in the adipogenic process of OP9 cells upon Drosha removal. Further exploration showed that the activity of ERK1/2, which has been shown to be able to suppress the transcriptional activity of PPARγ, was significantly increased in Drosha KO OP9 cells. Introducing miR-204 or miR-15b into OP9 cells significantly enhanced their adipogenic capacity and partially rescued the adipogenic defects caused by Drosha knockout. Mechanistically, miR-15b regulates ERK mediated adipogenic differentiation via repressing NRP2. Our data demonstrate that the Drosha/miR-15/NRP2 axis regulates adipogenesis of MSCs by modulating the ERK/PPARγ pathway. This discovery unveils a previously unappreciated molecular mechanism governing MSC adipogenic differentiation and suggests new avenues for exploring the therapeutic potential of MSCs.