Fig. 2

Cytokines induce catabolic response in the mature NP subclones. a Heatmap representation of gene expression changes in distinct NP subclones. NP cell clones NP-nR 105 and NP-R 124 were stimulated for two days with anabolic factors TGFβ3 (10 ng/ml), GDF6 (100 ng/ml), CTGF (100 ng/ml) or catabolic factors IL-1β (10 ng/ml) or TNFα (50 ng/ml). mRNA levels for the following genes was determined: KRT19, T, COL2A1, SOX9, VCAN, COL1A1, MMP3 and ADAMTS4. Gene expression was normalized to the average of EIF2B1 and MRPL19 expressions. Fold induction was calculated by comparison to untreated cells at day 2 and is represented in a heatmap; n.d.: not determined. Asterisks indicate significantly different expression level; p < 0.05. b Protein expression of EGR1 in response to maintenance medium (med), differentiation medium (diff), IL-1β (10 and 100 ng/ml) or Valproic acid (0.3 and 1 mM). NP-nR 105 and NP-R 115 samples were run on the same gel to allow direct comparison. The indication (t+) points to relatively long apposition times. Β Actin was used as loading control. c Three NP-nR and three NP-R clones were either left undisturbed (con), exposed to a change of maintenance medium (med) or medium supplemented with IL-1β (10 ng/ml) for two hours. Non-stimulated cells at time point t = 0 were used as control (con). Βeta Actin (βACT) was used as loading control