Fig. 3. Htra1 regulates the expression of osteogenesis-related genes during differentiation of primary mesenchymal progenitor cells. Osteogenesis gene expression array was carried out at d7 in primary mesenchymal progenitor cells transfected with empty vector or Htra1 overexpression vector during osteogenic differentiation. Differentially expressed genes between the empty vector and Htra1-overexpressing osteoblasts are plotted in the bar graph (A; n=3 biological replicates). Data were normalized to Gapdh Ct values of the respective samples; mean ± S.E.M; Two-tailed unpaired T-test was carried out for each gene separately and represented relative to respective empty vector transfected cells. Relative mRNA expression of osteoblast markers Sp7 (Osx) (B) and Alpl (C) at d7 and d15 in primary mesenchymal progenitor cells after overexpression of Htra1. Compared to empty vector-transfected cells and Htra1 (mut)-transfected cells, overexpression of Htra1 significantly upregulated the gene expression of Sp7 and Alpl at d7 and at d15 (B and C). Data were normalized to 18s rRNA (n=4 biological replicates; mean ± S.E.M; one-way ANOVA with Bonferroni posthoc test, *, p<0.05; **, p<0.01; ***, p<0.001) and represented relative to cells transfected with empty vector.