骨质疏松（OP）是严重危害人类健康的骨退行性疾病。骨髓间充质干细胞（BMMSC）的成骨分化与OP发病密切相关。环状RNA在OP发病中的作用显著，但机制不清。前期研究发现，SFRP1可以抑制BMMSC的成骨分化，hsa_circ_0021245在OP患者BMMSC中高表达且与SFRP1相关，hsa-miR-144-3p靶向抑制SFRP1的表达，hsa_circ_0021245可能负调控hsa-miR-144-3p且两者均与BMMSC成骨分化相关。据此，我们假设：hsa_circ_0021245可能通过竞争性结合hsa-miR-144-3p上调SFRP1的表达抑制BMMSC的成骨分化。本项目拟通过RIP/双荧光素酶等分子互作实验阐明hsa_circ_0021245/hsa-miR-144-3p/SFRP1信号通路在骨髓间充质干细胞成骨分化中的调控作用和分子机制，以丰富骨质疏松发病机制的新理论。

Osteoporosis (OP) is a bone degenerative disease that seriously endangers human health. Osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs) is closely related to the pathogenesis of OP. The role of circRNA in the pathogenesis of OP is significant, but the mechanism is unclear. Previous studies have found that SFRP1 can inhibit osteogenic differentiation of BMMSCs. Hsa_circ_0021245 was highly expressed in BMMSC of OP patients and was associated with SFRP1. hsa-miR-144-3p targeted to inhibit the expression of SFRP1. Hsa_circ_0021245 may negatively regulate hsa-miR-144-3p and both were associated with osteogenic differentiation of BMMSCs. Accordingly, we hypothesized that hsa_circ_0021245 may inhibit osteogenic differentiation of BMMSCs by competitively binding hsa-miR-144-3p to up-regulate SFRP1 expression. This project intends to demonstrate the regulation and molecular mechanism of hsa_circ_0021245/hsa-miR-144-3p/SFRP1 signaling pathway in osteogenic differentiation of BMMSC through molecular interaction experiments such as RIP/dual luciferase to enrich the new theory of the pathogenesis of osteoporosis.