The Role Of COX-2on BMP9Induced Osteogenic Differentiation In Mesenchymal Stem Cell

Aim：To investigate the effect of COX-2on BMP9induced osteogenicdifferentiation in mesenchymal stem cell, and dissect the possiblemechanism for COX-2in this process.Methods： We introduced the exogenous expression and smallinterference RNA, chemiluminecence and histochemical stain, Alizarin RedS stain, Western blot, and PCR techniques to carry out the effect of COX-2on the osteogenesis induced by BMP9in C3H10T1/2cells.The detail methods as following:1. COX-2selective inhibitor was employed to test the importance ofCOX-2in BMP9induced osteogenic differentiation in C3H10T1/2cells.2. Exogenous over-express or knockdown of COX-2mediated byrecombinant adenovirus were intrudoced to demonstrate the effect ofCOX-2on BMP9induced osteogenic differentiation in C3H10T1/2cells.3. Ecotopic osteogenesis assay was used to evaluate the effect ofCOX-2on BMP9induced osteogenesis in C3H10T1/2cells. 4. With reporter assay, Western blot, and PCR techniques to unveil thepossible mechanism of how COX-2affects the osteogenic differentiationinduced by BMP9in C3H10T1/2cells.Results：1. COX-2selective inhibitor or COX-2knockdown can inhibitosteogenic differentiation induced by BMP9in MSCs, but exogenousover-expression of COX-2can enhance the osteogenic differentiationinduced by BMP9in C3H10T1/2cells.2. COX-2selective inhibitor or COX-2knockdown reduces theexpression of Runx2, Dlx-5, and Osterix in MSCs induced by BMP9,however exogenous over-expression of COX-2increases the expression ofthese critical osteogenic regulatory factors in C3H10T1/2cells induced byBMP9.3. Exogenous over-expression COX-2increases ectopic osteogenesis,and COX-2knockdown decreases the ecotopic osteogenesis induced byBMP9, inclcuding the quantity and the quality of the bone masses.4. COX-2can facilitate the BMPs/Smads signal transduction initiatedby BMP9in C3H10T1/2cells.Conclusion： COX-2plays an important role in BMP9inducedosteogenesis in MSCs, this maybe mediated by through enhancing theBMPs/Smads signal transduction initiated by BMP9at least partly.