Bone formation is critically needed in orthopedic clinical practice. We found that, bone morphogenetic protein-7 (BMP-7) gene expression was significantly increased in fractured mice, which activates canonical Wnt signaling exclusively in osteocytes. Wnt and BMP signaling appear to exhibit synergistic or antagonistic effects in different kinds of cells. However, the communication between Wnt/β-catenin signaling and BMP signaling in osteocytes is almost unknown. Our study verified in vitro that BMP-7 expression was significantly increased when Wnt signaling was activated in osteocytes. Next, BMP-7 in osteocytes was overexpressed using an adenovirus, the osteogenesis of bone marrow stem cells (BMSCs) was enhanced, when cocultured with osteocytes. On the contrary, BMP-7 in osteocytes was silenced using an adenovirus, the osteogenesis of bone marrow stem cells (BMSCs) was weakened. In addition, the osteogenesis of BMSCs was no longer promoted by Wnt-activated osteocytes when BMP-7 was silenced. Therefore, the results showed that BMP-7 mediated the anabolic actions of Wnt/β-catenin signaling in osteocytes. Our study provides new evidence for the clinical application of BMP-7-overexpressed osteocytes.

Osteoporosis is a systemic bone disorder characterized by decreased bone mass and deteriorated microarchitecture, leading to an increased risk of fractures. Recent studies have revealed that its pathogenesis involves complex biological processes beyond bone remodeling, including oxidative stress, chronic inflammation, cellular senescence, osteoimmunology, gut microbiota alterations, and epigenetic modifications. Oxidative stress disrupts bone homeostasis by promoting excessive free radical production and osteoclast activity. Chronic inflammation and the accumulation of senescent cells impair skeletal repair mechanisms. Advances in osteoimmunology have highlighted the critical role of immune–bone crosstalk in regulating bone resorption and formation. Moreover, the gut–bone axis, mediated by microbial metabolites, influences bone metabolism through immune and endocrine pathways. Epigenetic changes, such as DNA methylation and histone modification, contribute to gene–environment interactions, affecting disease progression. Multi-omics approaches (genomics, proteomics, and metabolomics) systematically identify molecular networks and comorbid links with diabetes/cardiovascular diseases, revealing pathological feedback loops that exacerbate bone loss. In conclusion, osteoporosis pathogenesis extends beyond bone remodeling to encompass systemic inflammation, immunometabolic dysregulation, and gut microbiota–host interactions. Future research should focus on integrating multi-omics biomarkers with targeted therapies to advance precision medicine strategies for osteoporosis prevention and treatment.