Myricitrin promotes osteogenesis and prevents ovariectomy bone loss through PI3K/AKT signaling pathway

Abstract

Background: Osteoporosis is characterized by reduced bone mass and destruction of trabecular bone microstructure, increasing fracture risk. Newly marketed drugs have certain advantages in osteoporosis, but high health care expenditures and side effects limit their application. Therefore, it is urgent to explore new approaches to break the therapeutic deadlock in the current clinical condition. Myricitrin has many biological activities. However, the effect on antiosteoporosis has not fully been elucidated yet.Methods: The effect of myricitrin on the proliferation of immortalized bone marrow mesenchymal stem cells was evaluated using Cell Counting Kit-8 assays. Alizarin Red staining, Alkaline phosphatase staining, and activity were performed to elucidate osteogenesis. qRT-PCR and Western blot were performed to evaluate the expression of osteo-specific genes and proteins. To screen for candidate targets, sequencing of mRNA transcriptome genes was used through bioinformatics analysis. Western blot and Molecular docking analysis were used to examine target signaling markers. Rescue experiments were used to confirm myricitrin can enhance osteogenic differentiation of imBMSCs reversely. Moreover, ovariectomy mice were used to assess the effect of myricitrin on bone loss in vivo by Western blot, Micro-CT, Hematoxylin and Eosin staining, and immunochemistry.Results: Myricitrin can significantly enhance osteo-specific genes and proteins expression, alkaline phosphatase activity, and calcium deposition in imBMSCs in vitro. These phenomena were accompanied by an upregulation of the PI3K/AKT signaling pathway via bioinformatics analysis and Western blot. In addition, the improvement of osteogenesis due to myricitrin intervention was partially reversed by copanlisib, which is a PI3K inhibitor. Osteopontin (OPN), osteoprotegerin (OPG), p-PI3K, and p-AKT were significantly increased in the low dose and high dose myricitrin groups compared with the OVX group. Micro-CT, H&E staining, and immunochemistry showed that bone mass was significantly increased in low dose and high dose groups compared with the OVX group. Furthermore, myricitrin can attenuate bone loss in ovariectomy mice.Conclusion: These data suggest that myricitrin enhances the osteogenic differentiation of imBMSCs, partly via activation of the PI3K/AKT signaling pathway. Myricitrin may be a potential drug development for the treatment of postmenopausal osteoporosis.