Figure 2.

The inhibitory potential of nicotine (Nic), phosphocholine (PC) and C-reactive protein (CRP) on the BzATP-induced release of IL-1β by human monocytic and macrophage-like THP-1 cells is reversed by nitric oxide synthase (NOS) inhibitors. Monocytic (A) and differentiated macrophage-like (B) THP-1 cells were used. Cells were primed with lipopolysaccharide (LPS; 1 µg/ml, 5 h). Thereafter, the P2X7 receptor agonist BzATP ((2’/3’-O-(4-benzoylbenzoyl)adenosine-5’-triphosphate, tri(triethylammonium) salt) was added for another 40 min to trigger IL-1β release, which was measured by ELISA. The inhibitory potential of Nic (100 µM), PC (200 µM) and CRP (10 µg/ml) on the BzATP-induced release of IL-1β was investigated in absence and presence of the NOS inhibitors L-NIO (50 µM; N5-(1-iminoethyl)-L-ornithine dihydrochloride) or L-NAME (10 µM; N-omega-nitro-L-arginine methyl ester hydrochloride). (B) In experiments on macrophage-like THP-1 cells, the concentration of IL-1β released in response to BzATP was calculated by subtracting the IL-1β concentrations measured in supernatants of cells treated with LPS alone. In each experiment, the IL-1β concentration obtained after stimulation with BzATP was set to 100% and all other values were calculated accordingly. Data are presented as individual data points, bars represent median, whiskers encompass the 25th to 75th percentile. *p ≤ 0.05, different from LPS-primed cells stimulated with BzATP alone; #p ≤ 0.05 significantly different from samples, in which BzATP plus agonist was given. Friedman test followed by the Wilcoxon signed-rank test.