To establish whether Nell-1 blockade will inhibit Runx2-mediated osteogenic differentiation, wild-type NMCCs were pretransfected with Nell-1 siRNA (siRNANell-1) or unrelated negative control siRNA 24 hours prior to AdRunx2 infection and compared with AdRunx2 transduction alone and no treatment controls (Fig. 5A, B). This evidence concerns the gene RUNX2 and infection.