Ginsenoside compound K exerts osteoprotective effects by suppressing osteoclastogenesis and promoting preosteoclast PDGF-BB-induced angiogenesis via targeting CSF1R.

We previously found that oral administration of Panax notoginseng saponins (PNS) alleviated bone loss in ovariectomy(OVX)-induced osteoporotic mice. However, the specific active component responsible for this effect and its underlying mechanism remained unclear. Ginsenoside compound K (CK), one of the main active components of PNS, may serve as a promising therapeutic agent for osteoporosis. This study demonstrated that CK inhibited osteoclastogenesis and promoted type H vessel formation to alleviate bone loss in OVX mice. In vitro, CK concentration-dependently inhibited RANKL-induced osteoclastogenesis. In addition, high concentration CK inhibited the migration and tubule formation of HUVECs. However, treating HUVECs with CK + RANKL-stimulated RAW264.7 conditional medium showed enhancement of migration and tubule formation ability, which was blocked by adding PDGF-BB neutralising-antibody. Proteomics and network pharmacological analysis revealed CK may directly target CSF1R and inhibit osteoclast differentiation via PI3K/AKT/NFκB pathway, which subsequently conformed by drug affinity responsive target stability, cellular thermal shift, surface plasmon resonance and western blot assays. Furthermore, adding macrophage colony-stimulating factor (M-CSF) mitigated the inhibitory effect of CK on osteoclast differentiation and PI3K/AKT/NFκB pathway activation. Taken together, we demonstrated that CK exerts osteoprotective effects by targeting CSF1R to inhibit PI3K/AKT/NFκB pathway, thereby suppressing osteoclastogenesis and promoting preosteoclast PDGF-BB-induced angiogenesis.