FTO Promotes Osteogenic Differentiation of Human BMSCs via Demethylation of TGFB2 m⁶A Modifications

To elucidate the role of m⁶A modification in the osteogenic differentiation of human BMSCs (hBMSCs) and the underlying mechanisms.

In this research, we analyzed the m⁶A modification and its impact on mRNA expression and osteogenic differentiation of hBMSCs. FTO was knocked down in hBMSCs using shRNAs, and the effect on osteogenic differentiation was evaluated. m⁶A-seq was performed to identify key m⁶A-methylation mRNAs during osteogenic differentiation. TGFB2 was knocked down to validate its role in FTO-regulated m⁶A-methylation-mediated osteogenesis.

We found downregulated global m⁶A modification in osteogenically differentiating hBMSCs. m⁶A eraser FTO expression was upregulated during the osteogenic differentiation of hBMSCs. FTO knockdown inhibited the osteogenic differentiation of hBMSCs. Downregulation of mRNA m⁶A modification was prominent in osteogenically differentiating hBMSCs. mRNA m⁶A modifications in osteogenically differentiating hBMSCs were mainly attributed to MAPK, focal adhesion, and TGFβ signaling. Finally, we revealed that FTO demethylates m⁶A abundance of TGFB2, promoting the TGFB2 expression in hBMSCs. Knockdown of TGFB2 inhibited the osteogenic differentiation of hBMSCs.

These results indicate that upregulated m⁶A eraser FTO downregulates m⁶A modifications promoting TGFB2 expression in hBMSCs that trigger osteogenic differentiation, suggesting activation of FTO or TGFB2 as a strategy to promote hBMSC-based bone defect repair.