LBP1C-2 from Lycium barbarum alleviated age-related bone loss by targeting BMPRIA/BMPRII/Noggin.

Age-related bone loss is unavoidable and effective safe drugs are in great need. The fruit of Lycium barbarum was recorded to strengthen bones in the "Ben Cao Gang Mu (Compendium of Materia Medica)". However, there lacks scientific explanation. Herein, we investigated L. barbarum water extract (LBE), L. barbarum polysaccharides (LBP) and the homogeneous polysaccharide LBP1C-2 on the bone loss in adult mouse, aging mouse and ovariectomized mouse models. LBE, LBP and LBP1C-2 all markedly increased bone mass and bone strength in these models and promoted osteoblast proliferation, differentiation and ossification. Mechanistic studies showed that LBP1C-2 binds directly to the BMP receptors (BMPRIA and BMPRII) and noggin, activates the phosphorylation of Smad and disrupts the interaction between noggin and BMPs. Our results clearly elucidate the mechanism, the critical component and the direct targets of L. barbarum and provide potentially safe natural products and new drug candidate against age-related bone loss.