The Role And Mechanism Of Exosome Derived From Dental Pulp Stem Cells In Bone Tissue Engineering

Objective: To observe the effects of co-culture system of adipose stem cells and dental pulp stem cells on osteogenic differentiation ability,and to further explore the role and mechanism of exosomes derived from dental pulp stem cells.Method: After co-culture of adipose stem cells and dental pulp stem cells,the in vitro osteogenic ability was compared by alkaline phosphatase staining,semi-quantitative alkaline phosphatase and expression of osteogenic related genes.The exosome inhibitor GW4869 was used to detect whether exosomes derived from dental pulp stem cells promote osteogenic differentiation of adipose tissue–derived stem cells.The exosomes derived from dental pulp stem cells were extracted by ultracentrifugation and further identified.The osteogenic effects of exosomes on adipose-derived stem cells were verified by in vitro experiments.The role of molecular signaling pathways such as ERK,p38 and JNK was explored by western blotting and inhibition assays.Finally,the exosomes derived from dental pulp stem cells were applied to the rat bone defect model to evaluate the bone repair ability of the exosome.Result: In vitro experiments showed that the osteogenic ability of adipose tissue–derived stem cells and dental pulp stem cells was enhanced after co-culture.After the addition of the exosome inhibitor GW4869,the promoting effect of dental pulp stem cells on osteogenic differentiation of adipose-derived stem cells was weakened.It was further verified in vitro that exosomes can promote osteogenic differentiation of adipose stem cells.Osteoblast-induced adipose-derived osteogenic differentiation was also inhibited after ERK and JNK pathways were blocked,and ERK and JNK phosphorylation were enhanced by exosomes acting on adipose-derived stem cells.In the rat model of mandibular defects,it was found that exosome derived from dental pulp stem cells was significantly enhanced in new bone formation compared with the control group.Conclusion: Adipose-derived stem cells and dental pulp stem cells have stronger osteogenic differentiation ability,while exosomes secreted by dental pulp stem cells can promote osteogenic differentiation of adipose-derived stem cells.Exosomes may promote osteogenic differentiation of adipose-derived stem cells through ERK and JNK pathways..Exosomes derived from dental pulp stem cells can promote local bone repair.