[Effects of miR-31-5p on HIF-1α/BNIP3 signaling pathway and the expression of osteoblast-related factors of dental pulp stem cells].

Purpose: To investigate the effects of microRNA-31-5p (miR-31-5p) on the signal pathway of hypoxia inducible factor-1α (HIF-1α)/Bcl-2/adenovirus E1B 19-kDa-interacting protein 3(BNIP3) and the expression of osteoblast-related factors of dental pulp stem cells(DPSCs).
Methods: Human dental pulp stem cells (DPSCs) were cultured in vitro and divided into the control group (no transfection), mimic NC group (transfected with negative control-miR-31-5p), miR-31-5p mimic group (transfected with hsa-miR-31-5p mimic), siRNA NC group (transfected with nonsense siRNA) and miR-31-5p siRNA group (transfected with miR-31-5p siRNA).The expressions of miR-31-5p, HIF-1α, BNIP3, alkaline phosphatase(ALP) and Runt-related transcription factor-2(Runx2) mRNA in DPSCs were detected by real-time fluorescence quantitative PCR; the proliferation of DPSCs was detected by MTT; ALP activity of DPSCs was detected by ALP activity test kit; and the protein expressions of HIF-1α, BNIP3 and Runx2 in DPSCs were detected by Western blot. Statistical analysis was carried out with SPSS 24.0 software package.
Results: Compared with the control group and mimic NC group, the A value, ALP mRNA expression level and activity, Runx2 mRNA and protein expression levels of DPSCs in miR-31-5p mimic group were significantly lower (P＜0.05), ALP staining decreased significantly, and the expression levels of miR-31-5p mRNA, HIF-1α, BNIP3 mRNA and HIF-1α, BNIP3, Beclin1 protein were significantly higher (P＜0.05). Compared with the control group and siRNA NC group, the A value, ALP mRNA expression level and activity, Runx2 mRNA and protein expression levels of DPSCs in miR-31-5p siRNA group were significantly higher (P＜0.05), ALP staining enhanced significantly, and the expression levels of miR-31-5p mRNA, HIF-1α, BNIP3 mRNA and HIF-1α, BNIP3, Beclin1 protein were significantly lower(P＜0.05).
Conclusions: MiR-31-5p may inhibit the expression of osteoblast-related factors of DPSCs, and activating HIF-1α/BNIP3 signaling pathway.