Chondrocyte specific regulation by BMP inhibitors in a medsodermal stem cell C1 and skeletal cells

点击翻译按钮获取中文摘要

Osteoblast and chondroblast are derived from common mesenchymal progenitors. BMP induces mesenchymal cell differentiation into both osteogenic and chondrogenic pathways in vitro. Its (inhibitor, noggin, is expressed during the chondrogenic differentiation of mesodermal C1 cells cultured in the presence of dexamethasone, but it is not expressed during the osteogenic differentiation of C1 cells cultured in the presence of ascorbate and beta-GP We hypothesize that noggin may function in lineage-specific manner to block BMP action. To lest this hypothesis, we constructed an recombinant adenovinis to express noggin ( Ad/noggin) C1 cells are derived from an embryonal carcinoma cell 1003 and have characteristics of mesodermal cells. When C1 cells are cultured in aggregate form in differentiation medium, they differentiate into chondrogenic, osteogenic and adipogenic cells. When we infected Ad/noggin into C1 cells before induction of differentiation, endogenous alkaline phosphatase level in these cells was not altered compared with Ad/IacZ infected C1 cells. When Ad/noggin-infected C1 cells were induced to differentiate into chondrogenic lineage, expression of Sox9 and type X collagen mRNAs was reduced, showing noggin inhibition of chondrogenesis. In contrast, upon induction of C1 cells into osteogenic lineage, expression levels of osteoblast phenotypic markers, osteocalcin and alkaline phosphatase mRNAs, did not differ between Ad/noggin and lacZ- infected cells. We further examined if noggin may affect skeletal tissue development by using organ cultures of embryonic long bones. When we infected Ad/noggin into 15-5dpc hind limb bones, chondrogenic growth was inhibited compared with Ad/lac Z infected limb bones. These results suggest that noggin is a regulator of chondrogenic differentiation, rather than osteogenic differentiation, of mesodennal stem cell line Cl and skeletal cells.