METTL3 promotes immature dental pulp stem cells-induced angiogenesis by regulating ETS1 mRNA stability in an m6A-HuR-dependent manner.

Angiogenesis serves as the determinate element of pulp regeneration. Dental pulp stem cell (DPSC) implantation can promote the regeneration of dental pulp tissue. Herein, the role of m6A methyltransferase methyltransferase-like 3 (METTL3) in regulating DPSCs-induced angiogenesis during pulp regeneration therapy was investigated. Cell DPSC viability, HUVEC migration, and angiogenesis ability were analyzed by CCK-8 assay, wound healing, Transwell assay, and tube formation assay. The global and EST1 mRNA m6A levels were detected by m6A dot blot and Me-RIP. The interactions between E26 transformation-specific proto-oncogene 1(ETS1), human antigen R(HuR), and METTL3 were analyzed by RIP assay. The relationship between METTL3 and the m6A site of ETS1 was performed by dual-luciferase reporter assay. ETS1 mRNA stability was examined with actinomycin D. Herein, our results revealed that human immature DPSCs (hIDPSCs) showed stronger ability to induce angiogenesis than human mature DPSCs (hMDPSCs), which might be related to ETS1 upregulation. ETS1 knockdown inhibited DPSCs-induced angiogenesis. Our mechanistic experiments demonstrated that METTL3 increased ETS1 mRNA stability and expression level on DPSCs in an m6A-HuR-dependent manner. ETS1 upregulation abolished sh-METTL3's inhibition on DPSCs-induced angiogenesis. METTL3 upregulation promoted DPSCs-induced angiogenesis by enhancing ETS1 mRNA stability in an m6A-HuR-dependent manner. This study reveals a new mechanism by which m6A methylation regulates angiogenesis in DPSCs, providing new insights for stem cell-based tissue engineering.

[Clinical effect of MB-PDT assisted initial therapy on alveolar angle absorption of lower anterior teeth].

PURPOSE: To evaluate the effect of MB-PDT assisted essential therapy on angle resorption of lower anterior alveolar bone in patients with periodontitis. METHODS: Forty patients who were diagnosed with periodontitis stage III-IV or C, lower anterior teeth alveolar bone angle resorption, and periodontal pocket depth greater than 4 mm were selected from April 2018 to October 2020 in the Department of Periodontology and Oral Mucosal Diseases, Changsha Stomatological Hospital. The patients were randomly divided into control group and experimental group with 20 cases in each group. Compared with the control group which was only managed with essential treatment, the experimental group was treated with MB-PDT on the basis of the control group. The plaque index (PLI) and gingival bleeding index (GBI) scores of the two groups were recorded before surgery and 1 and 2 weeks after surgery. Probing depth (PD) and clinical attachment level (CAL) were detected before and 6 months after surgery. Statistical analysis of the data was performed using Graphpad Prism 5 software package. RESULTS: The PLI and GBI of the experimental group were significantly lower than those of the control group at 1 and 2 weeks after operation(P＜0.05). Six months after surgery, PD and CAL levels in the experimental group were significantly lower than those in the control group (P＜0.05). CONCLUSIONS: MB-PDT adjuvant therapy has the advantages of simple operation, efficient sterilization, promotion of healing, and high safety performance. It may be a new non-surgical adjuvant treatment strategy for effective treatment of lower anterior alveolar angular resorption.