Research On Strontium Promoting Osteogenic Differentiation Of ADSCs Through CaSR Pathway

Objective:At present,plastic surgery and maxillofacial surgery are facing a huge challenge.Bone defects can be caused by trauma,tumors,and infections.And this defect is difficult to repair.Adipose-derived stem cells?ADSCs?are self-renewing and multi-differentiated stem cells.In recent years,their osteogenic potential has gradually gained the attention of clinical experts.Numerous studies have shown that strontium?Sr?as an important trace element in human body can promote bone formation and reduce bone resorption in vivo and in vitro by inhibiting osteoclasts and promoting osteoblast replication.Calcium sensitive receptors?CaSRs?,a widely accepted receptor protein on the cell membrane,induce cellular responses by controlling signaling pathways.In this study,the mechanism of Sr2+promoting osteoblastic differentiation of adipose-derived stem cells was explored,revealing the role and relevance of CaSR in this process.By comparing ADSCs treated with CaSR blocker?NPS-2143?and osteogenesis-associated protein in untreated ADSCs,RUNX2 protein expression changes,to explore Sr2+induced ADSCs osteogenic differentiation mechanism,and protein levels for the CaSR in this process to promote the role of experimental basis.Methods:1,Extraction,culture and identification of the ADSCs in vitro;2,ADSCs were treated with culture medium containing NPS-2143 to establish a CaSR-silenced cell line,and a control group was alsoestablished.The optimal concentration of Sr²⁺was used to intervene the cells.The cells in each group were divided into control group,Sr²⁺group,NPS+Sr²⁺group and NPS group.All cells werecultured in standard osteogenic medium;3,the third generation of ADSCs cells were selected after 14 days of culture to extract proteins;4,to detect different groups of ADSCs CaSR protein expression and changesby Western blot method;5,The expression of RUNX2 protein in osteoblasts downstream of cellswere detected in each group.Results:Compared with Control group,there was no significant difference in CaSR protein expression between Sr²⁺group?p>0.05?.However,the expression of CaSR in the cell group with NPS2143 was significantly decreased?p<0.05?.The expression of RUNX2 in osteoblast-related gene was higher in Sr²⁺group than in Control group?p<0.05?,but lower in NPS+Sr²⁺group than in Sr²⁺group?p<0.05?.Srcl₂ can enhance the expression of RUNX2 protein,and when CaSR specific inhibitor NPS2143 is added,it can inhibit the expression of CaSR protein on the cell surface.Antagonize the up-regulation of RUNX2 protein by Sr²⁺and weaken the osteogenic differentiation ability of ADSCs.Conclusion:In vitro cultured ADSCs,Sr²⁺has a clear role in promoting osteogenic differentiation of ADSCs,and CaSR plays a crucial role in this process.Sr²⁺can promote the osteogenic differentiation of ADSCs by acting on CaSR.