Skip to main content
. 2013 Sep 27;8(9):e74953. doi: 10.1371/journal.pone.0074953

Figure 9. HuR silencing destabilizes Cox-2 mRNA in CSE-exposed AhR−/− lung fibroblasts.

Figure 9

Fibroblasts were transiently transfected with two siRNA against HuR (siRNA-1 and siRNA-2) or control (Ctrl) siRNA, exposed to CSE and Cox-2 mRNA stability evaluated by ActD chase experiments. (A) Transfection of AhR−/− fibroblasts with HuR siRNA significantly reduced HuR protein levels between 50–70%. Results are expressed as the mean ± SEM, n = 3 independent experiments per siRNA construct. (B) Cox-2 mRNA levels in AhR−/− fibroblasts transfected with Ctrl siRNA remained stable and did not significantly decline after exposure to ActD (ns = not significant compared to time 0). There was a significant decline in Cox-2 mRNA when HuR was knocked-down in AhR−/− cells (**p<0.01 compared to Time 0 of HuR siRNA). This decrease in Cox-2 mRNA following HuR siRNA-1 and siRNA-2 was significantly lower than the percentage of Cox-2 remaining in the Time 0 siRNA AhR−/− fibroblasts (*p<0.05; **p<0.01; ***p<0.001). Results are expressed as the mean ± SEM, n = 2–5 independent experiments. (C) AhR+/+ cells were transfected with two siRNA against HuR (siRNA-1 and siRNA-2); there was a significant reduction in HuR protein levels following knockdown (0.38±0.09- siRNA-1; 0.39±0.012- siRNA-2). Results are expressed as mean ± SEM of three independent experiments. (D) There was a significant decline in Cox-2 mRNA after exposure to ActD. Knock-down of HuR did not significantly affect the decay of Cox-2 mRNA levels (***p<0.001 compared to respective Time 0). There was no significant difference in the percentage of Cox-2 mRNA remaining between Ctrl, siRNA-1 or siRNA-2 (ns). Results are expressed as mean ± SEM of 2–4 independent experiments.