Figure 5
PDE2 expression and activity in BMDCs. (A) qPCR analysis of PDE2 expression in WT and NO-GC1 KO BMDCs and western blot of PDE2 in WT BMDCs and Cortex as a positive control (full-length blot is shown in the supplement: Supplementary Fig. 5). The relative quantification level (RQ) is based on comparison with WT “medium” (set as RQ = 1). (B,C) Activity of total PDEs and after inhibition of PDE2 in DC homogenates of WT (B) and NO-GC1 KO (C) as measured in cyclic nucleotide (NMP) turnover (=hydrolization) after supplementation of cAMP and/or cGMP. (D) Schematic hypothetical model of the NO-signaling regulating migration and T-cell polarization. The crosstalk of NO-GC1-derived cGMP and cAMP via PDE2 in (BM)DCs and the consequences on and T-cell fate. The second messenger cGMP is generated by the NO-activated NO-GC1. The cyclic nucleotide degrading PDE2 is activated upon cGMP-binding and hydrolyses cAMP which is generated by the Adenylat Cyclase (AC). The cAMP level within the (BM)DC biases the Th phenotype and is balanced by cGMP, with low/missing cGMP resulting in higher cAMP levels promoting Th1 differentiation and a high cGMP lowering the cAMP levels, thereby favoring Th2 differentiation. Lack of NO signaling enhances CCL19 production, which accounts for the impaired migration. Data are mean ± SEM of n = 3 (A) and n = 4 (B,C) independent experiments. One-way ANOVA with subsequent Dunn’s post test (A) or two-way ANOVA with subsequent Bonferroni’s post test (B,C) were performed. *P < 0.05, **P < 0.01, ***P < 0.001.
