Abstract: Objective:To explore the effect of METTL7A on cell senescence and osteogenic/odontogenic differentiation of DPSCs through m6A methylation. Methods:The lentivirus was used to transfect the DPSCs to obtain the DPSCs of METTL7A knockdown. The retrovirus was used to transfect the DPSCs to obtain the DPSCs of METTL7A overexpression. The knockdown and overexpression efficiency was detected by qRT-PCR and western blot assay. On this basis, SA-b-gal staining and quantification of the SA-b-gal staining was used to detect whether METTL7A regulated the cell senescence of DPSCs. Dot hybridization experiments were conducted to determine whether METTL7A regulated m6A methylation levels of DPSCs. After adding the Cyc to the METTL7A overexpression group, the SA-b-gal staining, the quantification of the SA-b-gal staining and ALP activity confirmed that METTL7A regulated cell senescence and osteogenic/odontogenic differentiation of DPSCs through m6A methylation. Results:The lentivirus was used to transfect the DPSCs. Compared with the Consh group, the gene and protein expression of METTL7A in METTL7A knockdown group (METTL7Ash) was significantly decreased (P<0.01). The quantity of positive cells was increased, which was detected by SA-b-gal staining and quantification of the SA-b-gal staining in METTL7Ash group (P<0.05). The retrovirus was used to transfect the DPSCs. Compared with the control group (Vector), the expression of METTL7A in the METTL7A overexpression group (HA-METTL7A) was significantly increased (P<0.01). The quantity of positive cells detected by SA-b-gal staining and quantification of SA-b-gal staining in the HA-METTL7A group was significantly decreased (P<0.01). In addition, compared with the control group, the m6A methylation modification level of DPSCs in the METTL7Ash group was significantly decreased, while the m6A methylation modification level of DPSCs in the METTL7A overexpression group was significantly increased. After adding the Cyc to the METTL7A overexpression group, the quantity of positive cells detected by SA-b-gal staining and quantification significantly increased compared with the METTL7A overexpression group (P<0.01). After adding the Cyc to the METTL7A overexpression group, the ALP activity was significantly inhibited that promoted by METTL7A overexpression (P<0.05). Conclusions: METTL7A may inhibit the cell senescence and promote osteogenic/odontogenic differentiation of DPSCs by regulating m6A methylation levels.

Key words: METTL7A, m6A methylation, dental pulp stem cell, cell senescence, osteo/odontogenic differentiation