Calpeptin promotes osteogenesis through the Dlx3-RUNX2 pathway: in vitro and in vivo evidence for a dual-action osteoporosis therapy.

Osteoporosis is a common systemic skeletal disease characterised by altered bone metabolism, decreased bone mass, deteriorated microstructure, and an increased risk of fractures. Current treatments primarily focus on inhibiting bone resorption to reduce bone loss. However, anti-resorptive agents alone cannot restore the lost bone microstructure. Therefore, developing dual-action drugs that both inhibit bone resorption and promote bone formation is a major research focus. In this study, we integrated network pharmacology and transcriptomics to screen for drugs that can be used to treat osteoporosis, and further identified compounds with potential synergistic effects in both inhibiting bone resorption and promoting osteogenesis. We found that calpeptin exhibited dual-intervention properties. Given its established anti-resorptive effect, we focused on exploring its osteogenesis-promoting mechanism. In vitro experiments demonstrated that calpeptin significantly enhanced osteogenic differentiation of BMSCs by activating the Dlx3-RUNX2 pathway. In an ovariectomy-induced osteoporotic mouse model, calpeptin treatment for 4 weeks alleviated bone loss and significantly promoted osteogenesis. This study reveals the unique mechanism by which calpeptin activates bone formation via the Dlx3-RUNX2 pathway, providing a new multi-target intervention paradigm for the development of breakthrough osteoporosis therapies.