Modulation of human monocyte-derived dendritic cells maturation by a soluble guanylate cyclase activator, YC-1, in a cyclic nucleotide independent manner

This study evaluated how YC-1, a guanylate cyclase activator, affects the maturation of human monocyte-derived dendritic cells. Maturation markers and intracellular signaling pathways were evaluated. YC-1 inhibited the lipopolysaccharide up-regulation of mature markers, including CD40, CD80 or CD86 in a concentration-dependent manner with IC50 values of 4.6 ± 0.4, 4.9 ± 0.6 or 4.5 ± 0.5 μM, respectively. YC-1, at a higher concentration, inhibited lipopolysaccharide-induced HLADR expression. These effects of YC-1 were not reversed by ODQ (10 μM), which is a soluble guanylate cyclase inhibitor, nor by KT5823 (1 μM), which is a PKG inhibitor. Additionally, YC-1 did not increase levels of cyclic nucleotides in dendritic cells, supporting the claim that YC-1 affects dendritic cells maturation in a cGMP-independent manner. YC-1, in a cGMP-independent manner, inhibited lipopolysaccharide-induced Akt activation, IκBα degradation and NF-κB translocation, all of which are associated with co-stimulatory molecules expression. YC-1 inhibited the capacity of dendritic cell to activate allogenic T cells with an IC50 value of 1.2 ± 0.3 μM. YC-1-treated dendritic cells have mature phenotypes that exhibit up-regulated CCR7, enhanced IL-10 release and low phagocytosis activity in the presence of lipopolysaccharide. In conclusion, YC-1 inhibited the lipopolysaccharide-induced co-stimulatory molecular expression of dendritic cells by inhibiting Akt activation, IκBα degradation and NF-κB translocation. These inhibitory effects on co-stimulatory molecules suppressed the capacity of dendritic cells to activate allogenic T cells. Additionally, YC-1 treated dendritic cells exhibit the up-regulation of CCR7, enhanced IL-10 release and the down-regulation of phagocytosis in the presence of lipopolysaccharide. Accordingly, YC-1 might be a useful tool for evaluation of dendritic cells on autoimmune or allergic disease.