LncRNA CTD-2555A7.2 promotes bone formation with LncRNA-specific cascade amplification strategy

Osteoporosis poses a significant threat to human health. Long non-coding RNAs (LncRNAs) have been deemed as crucial regulators in the pathogenesis of osteoporosis. However, the accuracy and efficiency of LncRNA-mediated regulation of bone formation require further improvement. Our previous study identified a repeat sequence in the human-derived LncRNA CTD-2555A7.2, suggesting its potential role in osteoporosis regulation. To investigate this hypothesis, we conducted systematic functional analyses of CTD-2555A7.2 in osteogenesis and explored its mechanisms and potential therapeutic applications. Through over-expression, siRNA silencing and repeat sequence over-expression in vitro and in vivo, our research demonstrate that CTD-2555A7.2 enhances bone formation by sequestering multiple miR-381-3p molecules through its repeat sequence. Through Western blot, siRNA silencing and luciferase reporter assay, we illuminated miR-381-3p suppresses osteogenic differentiation by concurrently targeting four essential genes of the Wnt signaling pathway: Apc, Lef1, wnt5a, and Lrp6. Notably, the mRNA of CTD-2555A7.2 repeat sequence exhibited pronounced therapeutic efficacy in ovariectomy osteoporosis models. Taken together, we identified a dual-amplification osteogenic axis (CTD-2555A7.2-miR-381-Wnt) that demonstrates significant regulatory effects on osteoporosis. This study has established an important theoretical framework for understanding osteogenic LncRNA mechanisms and provides novel insights for developing targeted therapeutics against osteoporosis.