[Role of m 6 A Reader YTHDC2 in Differentiation of Human Bone Marrow Mesenchymal Stem Cells].

Objective: To study the regulatory effect of YTH domain-containing protein 2 (YTHDC2), a member of N 6 -methyladenosine (m 6 A) readers, on the osteogenic or adipogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs).

Methods: YTHDC 2 expression was knocked down by small interfering RNA (siRNA) in vitro . Osteogenic differentiation and adipogenic differentiation of hBMSCs were induced after YTHDC 2 knockdown in order to study the changes in the differentiation phenotype of hBMSCs. Alkaline phosphatase staining (ALP staining) and alizarin red S staining were performed to examine osteogenic activity and calcium-nodular formation. Nile red staining was performed to examine lipid-droplet formation. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to assess the expression of osteogenesis and adipogenesis-related genes. RNA-sequencing was performed to identify the transcriptome changes after YTHDC 2 knockdown and to explore the potential regulatory mechanism by which YTHDC2 regulated the diferentiation of hBMSCs.

Results: In this study, we found that siRNA-induced YTHDC 2 knockdown resulted in increased ALP activity and calcium-nodular formation of hBMSCs during osteogenic differentiation, and significantly upregulated the expression of osteogenesis-related genes. In addition, the lipid-droplet formation capacity of hBMSCs was decreased during adipogenic differentiation. The expression of adipogenesis-related genes was significantly down-regulated. Gene-set enrichmen analysis of RNA-seq data showed that YTHDC2 was significantly correlated with ribosome function and mRNA-translation-related signaling pathways.

Conclusion: The findings indicate that YTHDC2 knockdown can promote the osteogenic differentiation of hBMSCs and inhibit the adipogenic differentiation. YTHDC2 knockdown may cause changes in ribosome function.