Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Enhance the Osteoblastic Differentiation of Periodontal Ligament Stem Cells Under High Glucose Conditions Through the PI3K/AKT Signaling Pathway

Objective High glucose (HG) can influence the osteogenic differentiation ability of periodontal ligament stem cells (PDLSCs). Human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-exo) have broad application prospects in tissue healing. The current study aimed to explore whether hUCMSC-exo could promote the osteogenic differentiation of hPDLSCs under HG conditions and the underlying mechanism. Methods We used a 30 mmol/L glucose concentration to simulate HG conditions. CCK-8 assay was performed to evaluate the effect of hUCMSC-exo on the proliferation of hPDLSCs. Alkaline phosphatase (ALP) staining, ALP activity, and qRT-PCR were performed to evaluate the pro-osteogenic effect of hUCMSC-exo on hPDLSCs. Western blot analysis was conducted to evaluate the underlying mechanism. Results The results of the CCK-8 assay, ALP staining, ALP activity, and qRT-PCR assay showed that hUCMSC-exo significantly promoted cell proliferation and osteogenic differentiation in a dosedependent manner. The Western blot results revealed that hUCMSC-exo significantly increased the levels of p-PI3K and p-AKT in cells, and the effect was inhibited by LY294002 (PI3K inhibitor) or MK2206 (AKT inhibitor), respectively. Moreover, the increases in osteogenic indicators induced by hUCMSC-exo were significantly suppressed by LY294002 and MK2206. Conclusion hUCMSC-exo promote the osteogenic differentiation of hPDLSCs under HG conditions through the PI3K/AKT signaling pathway.