Modulation of Osteogenic Differentiation by <scp>CYBB</scp> in Osteoporotic Models

Osteoporosis (OP) is a prevalent systemic skeletal disease characterized by increased bone fragility and fracture risk. Identifying factors that influence osteogenic differentiation in OP is crucial. We screened genes associated with OP from the Gene Expression Omnibus (GEO) database and constructed a weighted correlation network analysis (WGCNA) to identify hub genes, validating our findings in external and clinical cohorts. Various experiments assessed the proliferation, apoptosis, and osteogenic differentiation abilities of bone marrow mesenchymal stem cells (BMSCs) following CYBB knockdown. We established a postmenopausal OP model in rats through bilateral ovariectomy (OVX) and evaluated OP severity using three-dimensional computed tomography (3D-CT) and H&E staining. Differential gene expression analysis revealed that CYBB was significantly upregulated in OP, with the highest area under the curve (AUC) among differentially expressed genes (DEGs). Notably, CYBB expression in BMSCs decreased over time. Knockdown of CYBB promoted BMSC proliferation and reduced apoptosis, as demonstrated by Alizarin red and ALP staining, which indicated enhanced osteogenic differentiation. Markers such as RUNX1, RUNX2, ALP, secreted phosphoprotein 1 (SPP1), and bone sialoprotein (BSP) were upregulated post-knockdown. In vivo, CYBB knockdown improved bone mineral density (BMD), relative bone volume fraction (BV/TV), and trabecular number (Tb.N). In conclusion, CYBB influences OP progression by modulating bone formation.