WDR4-mediated m7G modification of ZBP1 mRNA drives peri-implantitis by promoting M1 macrophage polarization

Abstract Objective Macrophage polarization exerts a vital role in the progression of peri-implantitis. RNA methylation serves as an important regulator of macrophage polarization. However, reports on the role of N7-methylguanosine (m7G) regulators in peri-implantitis are scarce. Methods The function of m7G regulators in peri-implantitis and macrophage polarization was investigated via in vivo and in vitro experiments. RNA sequencing (RNA-seq) and m7G methylated RNA immunoprecipitation sequencing (m7G MeRIP-seq), and molecular biology assays were performed to identify and validate downstream m7G-modified target genes. Results WDR4 was identified as the sole significantly upregulated m7G-related gene in peri-implantitis tissues. Overexpression of WDR4 promoted macrophage M1 polarization, which further inhibited osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). RNA-seq revealed 3001 differentially expressed genes (DEGs) in WDR4-overexpressing macrophages, including 1503 upregulated genes and 1498 downregulated genes. m7G MeRIP-seq identified 554 m7G differential peaks between the control and WDR4 overexpression group. Integrative analysis of RNA-seq and m7G-MeRIP-seq identified 33 genes with both increased expression and enhanced m7G methylation, among which ZBP1 was selected as a key downstream target. WDR4 interacted with ZBP1 mRNA, increased its m7G modification, and enhanced its mRNA stability. Silencing ZBP1 significantly attenuated WDR4-induced M1 macrophage polarization and restored the impaired osteogenic differentiation of BMSCs. Conclusions WDR4 promotes M1 polarization of macrophages by enhancing the m7G modification of ZBP1, thereby inhibiting BMSC osteogenic differentiation and promoting peri-implantitis progression. Targeting the WDR4/m7G/ZBP1 axis may represent a potential therapeutic strategy for peri-implantitis.