Figure 5: T. serrulatus venom (TsV)-induced macrophages IL-1β production is amplified by PGE2 via the cAMP pathway.

(a) The relative mRNA expression levels for Ptger1, Ptger2, Ptger3 and Ptger4 are related to the expression level of Ptger3 in resting macrophages of C57BL/6 mice. The fold increase in mRNA expression after TsV stimulation for 2 and 6 h was determined in comparison with that in non-stimulated cells. (b) Macrophages pre-treated with PGE2 (0.01–10 μM, 10 min), were stimulated with TsV and 24 h later supernatants were collected for IL-1β quantification. (c) J774.1 macrophages were pre-treated or not with EP2 (AH6809 1 μM), or EP4 (AH23848 1 μM) antagonists, or indomethacin (Indo 10 μM), for 30 min, followed or not by PGE2 (10 μM, 10 min), before TsV addition. Supernatants were collected 24 h later for IL-1β quantification. (d) cAMP in J774.1 macrophage pre-treatment or not with EP2 antagonist (AH6809 1 μM), or indomethacin (Indo 10 μM) for 30 min; followed or not by PGE2 (10 μM, 3 min), before TsV addition for 5 min. (e) IL-1β production by J774.1 macrophages pre-treated or not with PKA inhibitor (H89 25 μM, 2 h); or forskolin (FSK 25 μM, 10 min), before TsV addition for 24 h. (f) J774.1 macrophages were pre-treated or not with PGE2 (10 μM), or forskolin (FSK 25 μM) for 10 min; or with PKA-inhibitor (H89 25 μM, 2 h), and then stimulated or not with TsV. Cell lysates were obtained 2 h later for phospho-NFκB p65 (Ser536) and total NFκB p65 quantification. (g) J774.1 were pre-treated or not with NFκB inhibitor (20 nM, 30 min), before TsV and the supernatant was collected 24 h later for IL-1β quantification. The data are representative of two independent experiments performed in triplicate. Macrophages were stimulated with 50 μg ml−1 of TsV. (h) A schematic representation of the cell signalling pathway for IL-1β production induced by TsV is shown. (a–g) Significant differences P<0.05 are marked with symbols and the error bars denote s.d. *Medium only versus stimulus or treatments, and #TsV versus treatments, according to one-way ANOVA with Bonferroni’s post-test.