Linoleic acid promotes osteogenic differentiation of bone marrow mesenchymal stem cells and ameliorates ovariectomy (OVX)-induced osteoporosis in mice through the PI3K/AKT pathway.

Bone mineral density (BMD) reduction is heavily involved in osteoporosis. Bone marrow mesenchymal stem cells (BMSCs) are promising candidates in the implantation treatment of bone loss-related diseases. Traditional Chinese herbs and their active components are effective in osteoporosis therapy. The effects of linoleic acid on osteogenesis and osteoporosis have been investigated in this study, revealing multifaceted findings through several analyses and experiments. A total of 41 overlapping disease-drug target genes were obtained between differentially expressed genes in osteoporosis and linoleic acid potential targets. Linoleic acid was shown to enhance BMSC osteogenic differentiation and mineralization in in vitro assays. Additionally, linoleic acid significantly countered bone loss and improved bone microstructure in a mouse model of osteoporosis induced by ovarian varixectomy (OVX) operation. Molecular docking was used to predict the interaction between linoleic acid and the top ten Hub genes. The predicted binding energy of Retinoid X Receptor Alpha (RXRA) is the lowest. Moreover, linoleic acid stimulation increased the expression of RXRA in BMSCs. Functional enrichment and pathway analysis of the overlapping potential targets highlighted their involvement in crucial biological processes and signaling pathways, including the PI3K-AKT signaling. Linoleic acid promoted the phosphorylation of PI3K and AKT. Lastly, the siRNA for RXRA knockdown and PI3K/AKT inhibitor LY294002 exerted opposite effects on BMSCs to linoleic acid, and significantly attenuated the effects of linoleic acid on BMSC osteogenic differentiation and the PI3K/AKT signaling activation, suggesting that the functions of linoleic acid might be mediated by the PI3K/AKT signaling. Moreover, linoleic acid also inhibited osteoclastogenetic differentiation. Conclusively, linoleic acid, the main active compound of Rehmanniae Radix Praeparata (RR), could promote BMSC osteogenic differentiation by enhancing the PI3K/AKT signaling activation.