m6A RNA modifications in neurosystem genes as early markers for osteoporosis with iron accumulation.

BACKGROUND: Postmenopausal osteoporosis is a prevalent bone disorder, and recent evidence suggests that iron accumulation, particularly within the nervous system, may exacerbate bone loss through epigenetic mechanisms. This study aims to investigate the role of m6A RNA methylation in the regulation of bone metabolism under conditions of iron overload in a postmenopausal osteoporotic model. METHODS: Fifteen female C57BL/6J mice were divided into three groups: sham-operated, ovariectomized (ovx), and ovariectomized with iron–dextran intervention (ovx+iron). Ovariectomy was performed at 8 weeks of age, followed by 8 weeks of iron–dextran administration to establish the model. Bone RNA samples were subjected to methylated RNA immunoprecipitation sequencing (MeRIP-seq) to profile m6A modifications. Bone morphology and iron status were evaluated using microCT scanning, immunohistochemistry, and Prussian blue staining. RESULTS: The ovx+iron group exhibited a higher number of m6A peaks (27,167) compared to the ovx group (21,441), with significant differences in methylation patterns. Upregulated differentially methylated genes (DMGs) were enriched in pathways related to nervous system development and skeletal morphogenesis, while downregulated DMGs were associated with epithelial morphogenesis and Wnt signaling. Integrative analysis identified 150 genes with concurrent alterations in mRNA expression and m6A modification, highlighting neural regulatory influences on bone mass under iron accumulation. Notably, Lep, a critical neural regulator, showed reduced expression and decreased m6A methylation in the ovx+iron group, which was further confirmed at the protein level by immunohistochemistry. CONCLUSION: Iron accumulation induces significant changes in m6A methylation, which may disrupt bone metabolism by modulating neural factors such as Leptin. These findings suggest that Leptin could serve as a potential early diagnostic biomarker for postmenopausal osteoporosis complicated by iron overload.