Fig. 4

Functional assays in human mesenchymal stem cell-induced osteoblasts following siRNA knockdown of four genes each at three loci implicated by GWAS and variant-to-gene mapping. a, e, i Representative alkaline phosphatase (blue) and Alizarin Red S (red) stains for osteoblastic activity and calcium deposition, respectively, for the three tested loci. Experiments were performed twice in three unique donor lines. b, f, j Quantification of alkaline phosphatase staining using quantitative image analysis was repeated twice with three different independent hMSC donor cell lines. c, g, k ALPL gene expression. d, h, l Quantification of Alizarin Red S staining. *p < 0.05 comparing no treatment to BMP treatment for each siRNA, ^#p < 0.05 comparing control siRNA to siRNA for gene of interest, n.s = not significant. Error bars represent standard deviation. hMSC donor line, siRNA, and qPCR details are given in Additional file 1: Tables S19-S21