METTL14 promotes TBK1 mRNA stability through IGF2BP3-recognized m6A modification and enhances mitophagy in BMSCs

Abstract

Osteoporosis, particularly postmenopausal osteoporosis, represents a growing global health challenge characterized by impaired bone remodeling and increased fracture risk. The impairment of bone regeneration manifests in the field of oral and maxillofacial medicine as delayed alveolar bone healing after tooth extraction and poor osseointegration of dental implants, significantly compromising oral functional rehabilitation. This study investigates the role of METTL14 in osteogenic differentiation and its potential regulatory mechanisms in bone metabolism. We identified differential expression patterns of METTL14 in bone marrow-derived mesenchymal stem cells (BMSCs) between osteoporotic patients and healthy controls. Through loss-of-function experiments, we further demonstrated the critical role of METTL14 in promoting osteogenic differentiation, providing direct evidence for its functional importance in bone metabolism regulation. Transcriptome sequencing analysis revealed a significant association between METTL14 and mitophagy. JC-1 assay, Mitosox assay, mt-Keima assay, western blotting and immunofluorescence demonstrated METTL14's positive regulatory role in mitophagy, with TBK1 identified as the most significantly altered downstream target through qRT-PCR and rescue experiments. We further elucidated that IGF2BP3, an m6A reader, promotes osteogenesis and regulates TBK1 mRNA stability, as evidenced by Actinomycin D treatment and mitochondrial-lysosomal colocalization assays. In vivo experiments showed that METTL14 overexpression enhanced alveolar bone healing in ovariectomized osteoporotic mice. These findings provide novel evidence supporting METTL14 as a potential therapeutic target for osteoporosis.