Nuciferine prevents bone loss by disrupting multinucleated osteoclast formation and promoting type H vessel formation

Recently, type H vessels were reported to couple angiogenesis and osteogenesis during osteoclastogenesis, and tartrate-resistant acid phosphatase (Trap)⁺ preosteoclasts were found to secrete increased PDGF-BB to promote type H vessel formation. Therefore, utilization of type H vessels may be a strategy to treat diseases involving bone loss. In the present study, we found that nuciferine, a natural bioactive compound, has various effects, including inhibiting osteoclastogenesis and promoting type H vessel formation. Nuciferine inhibited osteoclastogenesis and bone resorption but increased the relative number of Trap⁺ preosteoclasts. Nuciferine restrained the expression of osteoclast-specific genes and proteins, promoted PDGF-BB production and potentiated related angiogenic activities by inhibiting the MAPK and NF-κB signaling pathways in vitro. We confirmed the bone-protective effects of nuciferine in ovariectomized mice and found that nuciferine treatment increased the PDGF-BB concentration and the number of type H vessels in the femur. In conclusion, our results demonstrated that nuciferine can decrease multinucleated osteoclast formation and promote type H vessel formation through preservation of Trap⁺ preosteoclasts via inhibition of the MAPK and NF-κB signaling pathways and may be an excellent agent for the treatment of diseases involving bone loss.