Reduced levels of MMP9 and soluble KITL in a Crebbp^+/− microenvironment. (A) Heat map of genes that encode secreted and cell-surface molecules found to be significantly different between Crebbp^+/− (C 1-4) and wild-type (Wt 1-4) BM stroma, but not between Ep300 (P 1-4) and wild-type stroma. Pearson correlation was used for the hierarchical clustering. Each column represents an independent BM stroma sample, and each row represents the gene indicated by its symbol on the right. Expression values were row normalized, and the color represents the relative expression levels as indicated by the scale below the heat map. The black circles on the far right indicate the stroma cell type in which the expression of the gene had been reported previously. (B) Relative Mmp9 expression levels in Wt, Crebbp^+/−, and Ep300^+/− BM stroma measured by qRT-PCR (n = 6). The values from Wt were set at 1 (*P < .05). (C) Representative Western blot showing MMP9 protein levels in equal volumes of supernatant of Wt, Crebbp^+/−, and EP300^+/− BM stroma cultures of similar cell density. The lower panel represents the quantification of 3 independent Western blot experiments. The value of MMP9 in the wild-type BM stroma supernatant was set at 1 (*P = .003). (D) Average concentration ± SEM of soluble KITL measured by ELISA in serum samples obtained from Wt, Crebbp^+/−, and Ep300^+/− mice (n = 14-17; *P = .002).