Fig. 4

Inhibitory effect of NAC on WNT3A-induced WNT signalling. a ARPE19 cells were pretreated for 1 h with NAC (1 mmol/l) prior to incubation with WNT3A-conditioned medium for 6 h. Glutathione (GSH) levels in the medium were measured using a commercial kit and expressed as per cent of those in control medium. Values are mean ± SD; n = 3; **p < 0.01. b ARPE19 cells were transfected for 8 h with the TOPFLASH or FOPFLASH plasmid, and then pretreated for 1 h with NAC (1 mmol/l) prior to incubation with WNT3A-conditioned medium for another 16 h. TOPFLASH activity (white bars) and FOPFLASH activity (grey bars) were measured by luminometer and normalised to Renilla luciferase activity. Values are mean ± SD; n = 3; **p < 0.01 for WNT3A compared with control; ^† p < 0.05 for WNT3A+NAC compared with WNT3A. c Phosphorylated (p)LRP6 and total LRP6 levels were determined with western blot analysis using 50 μg of total proteins from each sample. d pLRP6 was quantified by densitometry from three independent experiments, normalised to β-actin levels, and expressed as per cent of that in cells treated with control L medium. Values are mean ± SD; n = 3; **p < 0.01 for WNT3A compared with control; ^†† p < 0.01 for WNT3A+NAC compared with WNT3A