Tmem251 knockdown induces chondrocyte dedifferentiation
Two different siRNAs decreased TMEM251 expression by 2.6 fold (p<0.001) and 1.6 fold (p<0.01) respectively, 48hrs after transfection of rat primary chondrocytes, compared to chondrocytes transfected with scrambled siRNA (Figure 4E). To determine whetherTmem251 knockdown affects chondrocyte differentiation, we investigated the expression levels of chondrocyte differentiation markers, such as Alkaline phosphatase (Alpl ) and Collagen type 2 (Col2a1 ). Expression of chondrogenic markers was not altered in cells treated with scrambled siRNA. In contrast, Tmem251knockdown did not affect Alpl expression (Figure 4F) but significantly reduced Col2a1 expression by 1.4 fold (p<0.05) and 2.2 fold (p<0.001) respectively for the two siRNAs tested (Figure 4G). Reduction of Col2a1expression, but not Alpl, expression in Tmem251knockdown cells, suggests that TMEM251 is important for chondrocytic, but not hypertrophic differentiation, and is perhaps particularly required for maintenance of the chondrocytic phenotype.(Ma et al., 2013)