Figure 6.

Comparison of exogenous versus endogenous CCN3 on COL1 promoter activity. Control, empty vector, transiently transfected MCs were exposed to rmCCN3 at the indicated concentrations. hCCN3-transfected MCs received no added CCN3. COL1 activation was measured by luciferase production. *P < 0.05 compared with no added CCN3 (control-transfected). In the absence of TGF-β stimulation there was little activation of the COL1 promoter and no effect of CCN3 except a slight reduction in cells transfected with CCN3 (white bars). With TGF-β treatment (2 ng/ml, black bars) the COL1 promoter was strongly activated and was markedly reduced by either increased endogenous or exogenous CCN3.