Human umbilical cord mesenchymal stem cell-derived exosomes promote osteogenesis in glucocorticoid-induced osteoporosis through PI3K/AKT signaling pathway-mediated ferroptosis inhibition

Abstract Glucocorticoid-induced osteoporosis (GIOP), the most common cause of secondary osteoporosis, is characterized by significant bone loss, decreased bone quality, and increased fracture risk. The current treatments for GIOP have several drawbacks. Exosomes are vital for cellular processes. However, very few studies have focused on using human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-EXOs) for GIOP treatment. In vitro and in vivo dexamethasone was used to evaluate the therapeutic effects of hUCMSC-EXOs on GIOP. CCK-8 and EdU assays were used to evaluate cell viability and proliferation, respectively. We conducted an alkaline phosphatase activity assay, alizarin red staining, Western blotting, and real-time PCR to detect the effect on osteogenesis. TMT-labeled quantitative proteomic and bioinformatic analyses were performed. Furthermore, we performed Western blotting, immunofluorescence, reactive oxygen species assays, and lipid peroxidation assays to investigate the regulatory mechanism by which hUCMSC-EXOs affect cell proliferation and osteogenic differentiation. The in vivo effects of hUCMSC-EXOs were evaluated using micro-CT, hematoxylin, and eosin staining, and immunohistochemical staining. We found that hUCMSC-EXOs reversed the inhibitory effects of glucocorticoids on human bone marrow stromal cell (hBMSC) proliferation and osteogenic differentiation and demonstrated that hUCMSC-EXOs reversed GIOP via the PI3K/AKT signaling pathway, inhibiting lipid peroxidation in vitro and in vivo. HUCMSC-EXOs promote hBMSC osteogenesis through the PI3K/AKT signaling pathway, inhibit ferroptosis, and have therapeutic potential for GIOP in mice.