Study Of The Effect And Mechanism Of Chondrocytes-derived Exosomes On Bone Marrow Mesenchymal Stem Cells

Background:In the research of cartilage tissue engineering,it is found that chondrocytes could promote chondrogenic differentiation of bone marrow mesenchymal stem cells(BMSCs).However,the mechanism is not clear.Exosomes is a popular research field in recent years for its crucial role in communication between different cells.Whether exosomes play a role in the communication between chondrocytes and BMSCs needs further study.Objective:The present study is aimed to confirm whether exosomes play a role in the communication between chondrocytes and BMSCs and then do the further study on the mechanismMethods:The exosomes of chondrocytes were extracted by ultracentrifugation from the culture medium and verified from three aspects:markers,sizes and shapes.Then the exosomes were co-cultured with BMSCs.The indicators of chondrogenic differentiation were tested by RT-PCR,western blot and alcin blue staining Furthermore,exsomal miRNA was analyzed.Luciferase reporter assay,miRNA mimics,miRNA inhibitors,shRNA and other methods were used to explore the further mechanism.Results:The exosomes of chondrocytes were successful extracted and the chondrogenic effect on BMSCs were confirmed.After further study on the mechanism,it was found that miR-8485 in exosomes could not only targeted GSK3B to repress GSK-3? expression,but also targeted DACT1 to suppress GSK-3? activity As a result,cumulated ?-catenin activated Wnt/b-catenin pathways and resulted in the chondrogenic differentiation of BMSCs.Conclusion:In the present study,we found that chondrocyte-derived exosomes could promote the chondrogenic differentiation of BMSCs.And the exosomal miR-8485 could regulate GSK-3? and activate Wnt/b-catenin pathways to promote the chondrogenic differentiation of BMSCs.