PR171(Carfilzomib) Alleviates Osteoporosis By Inhibiting The Activation Of Wnt Signal By PSME1/2.

Objective: We want to investigate the relationship between PR171 and osteoporosis and its effects on bone formation and osteodifferentiation,investigate the specific molecular biological mechanisms,and explore whether PR171 can regulate the Wnt/β-catenin signaling pathway by regulating PSME1 and PSME2,as well as providing new insights into the treatment of osteoporosis.Methods:(1)After adding PSME1,PSME2 and PSME1 + PSME2 into C3H10 cell culture medium,the proliferation and differentiation of C3H10 cells were observed by ARS staining.The mRNA expression of ALP,BMP2,COL1A1,OCN,osterix and Runx2 in C3H10 cells was determined by RT-PCR.The expression levels of β-catenin and OCN in RAW264.7 cells were observed by immunofluorescence double staining.(2)We establish OVX mouse model.The expression of PSME1 in osteoblasts and osteoclasts was detected by immunofluorescence double staining with OCN + PSME1 and CTSK + PSME1 respectively.The expressions of β-catenin,PSME1 and PSME2 were detected by immunofluorescence in ovariectomized osteoporosis tissues.Micro-CT was used to evaluate the bone condition,HE and TRAP staining were used to evaluate the differentiation,and immunofluorescence was used to detect the expression of OCN and β-catenin,PSME1 and PSME2.Results:(1)PSME1 and PSME2 inhibited the expression of β-catenin and OCN in C3H10 cells.PSME1 and PSME2 enhanced the expression of CTSK and MMP9 in RAW264.7 cells,but PR171 reversed the effect.(2)The expression levels of PSME1 and PSME2 in osteoblasts and osteoclasts of OVX mice were significantly higher than those in sham group.In ovariectomized osteoporosis,PSME1 and PSME2 were highly expressed andβ-catenin was low expressed.Micro-CT showed that BMD,BV / TV,trabecular number,trabecular separation,trabecular thickness of OVX + PR171 group were significantly higher than those of OVX group.HE and TRAP staining further confirmed that PR171 injection can alleviate osteoporosis.After PR171 treatment,the expression of OCN was increased,the expression of β-catenin was increased,and the expression of PSME1 and PSME2 was inhibited.Conclusion:(1)PSME1 and PSME2 activate proteasomal signaling to promote β-catenin degradation,and PR171 by inhibiting the proteasome,can increase β-catenin content,promote osteoblastogenesis,and inhibit osteoclast differentiation,thereby exerting anti osteoporotic effects.(2)PSME1 and PSME2 are closely related to osteoporosis,and the expression of PSME1 and PSME2 is increased in osteoporotic mice.Decreasing PSME1 and PSME2 can effectively inhibit the progression of osteoporosis and promote bone formation in mice.Therefore,PR171 may become a new idea and direction for the treatment of osteoporosis.