WTAP Contributes to Periodontitis Pathogenesis by Promoting PDLSC Senescence and Impairing Osteogenic Differentiation via m6A-Dependent Regulation of TP53BP1.

BACKGROUND: Periodontitis, a chronic inflammatory disease, represents the primary cause of tooth loss in Chinese adults. Wilms tumor 1-associating protein (WTAP) is a key component of the N6-methyladenosine (m6A) methyltransferase complex, and has an unclear role in periodontitis pathogenesis, particularly concerning its regulatory functions in periodontal ligament stem cells (PDLSCs). METHODS: The target gene was identified through the GES260558 dataset and Genecards database. Gene expression was measured using reverse transcription-quantitative PCR (RT-qPCR) and western blot. Periodontitis-derived PDLSCs (P-PDLSCs) were isolated and identified by alkaline phosphatase (ALP) staining, oil red O staining, and flow cytometry. Malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) levels, γ-H2AX and SA-β-gal positive cells, and the expression of p53 and p16 were applied to reflect oxidative stress and cell senescence. Osteogenic differentiation was assessed by ALP activity, alizarin red S (ARS) staining, and related gene expression. The m6A-dependent regulation of tumor protein p53 binding protein 1 (TP53BP1) mRNA by WTAP was confirmed using methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation (RIP), and Actinomycin D (Act D) assays. RESULTS: WTAP was identified as a candidate gene that was upregulated in periodontitis gingival tissues. Isolated P-PDLSCs retained normal multilineage differentiation potential. WTAP knockdown significantly reduced senescence and oxidative stress in P-PDLSCs while enhancing osteogenic differentiation. Mechanistically, WTAP mediated the m6A modification of TP53BP1 mRNA, and the effects of WTAP on P-PDLSC senescence, oxidative stress, and osteogenic differentiation were dependent on TP53BP1. CONCLUSION: The WTAP/TP53BP1 axis impairs periodontal tissue regeneration by promoting P-PDLSC senescence and suppressing osteogenic differentiation in an m6A-dependent manner, revealing a new cellular-level target for treating periodontitis.