TLR Signalling Pathways Diverge in Their Ability to Induce PGE₂

Figure 4

Lack of AA mobilization blocks the release of PGE₂ upon TLR1/2 and TLR2/6 stimulation. (a) DCs were stimulated with TLR agonists for 24 h. The expression of COX2 and β-actin was determined by Western blot. Fluorogram from one out of 3 representative donors and its densitometric analysis are shown. (b) DCs were stimulated with TLR agonists for 30 min and the phosphorylation of cPLA₂ was determined by immunoblot. One out of 3 representative donors and its densitometric analysis are shown. (c) DCs were labelled with 0.125 μCi/mL [¹⁴C] AA overnight and then stimulated with the indicated TLR ligands for 3 h. The results are expressed as the means ± SEM () of the percentage of [¹⁴C] AA release on the total radioactivity recovered from each stimulation; by one-way ANOVA with Dunnett’s post hoc test. (d) DCs were incubated with TLR ligands in the presence (black bars) or absence (white bars) of 10 μM AA. After 24 h, supernatants were collected and the production of PGE₂ was evaluated by EIA. Results are expressed as mean ± SEM (); by one-way ANOVA with Dunnett’s post hoc test.