Fig. 5

Wnt–β-catenin signaling suppress CCN2 expression through the mitogen-activated protein kinase (MAPK) pathway in rat nucleus pulposus (NP) cells. a-b NP cells transfected with the CCN2 reporter plasmid together with the pGL4.74 plasmid were treated with 6-bromoindirubin-3′-oxime (BIO) (1.0 μM) and the extracellular signal-related protein kinase (ERK) inhibitor (PD98059, 25 or 50 μM) (a) or the p38–MAPK inhibitor (SB202190, 1 or 10 μM) (b). c-e Rat NP cells transfected with the CCN2 reporter plasmid were cotransfected with different concentrations of the wild-type (WT)-ERK1 (c), (d) WT-ERK2, or (e) WT-p38 expression vector together with BIO (1.0 μM). Results are presented as mean and 95% CI (n = ≥ 6 for each group). One-way analysis of variance with the Tukey-Kramer post-hoc test was used for all experiments