Additional file 1: Figure S1. of Apremilast, a novel phosphodiesterase 4 (PDE4) inhibitor, regulates inflammation through multiple cAMP downstream effectors

Adenosine A2A receptor (A2AR) activation and apremilast do not additively increase responsive element binding protein (cAMP). Raw 264.7 cells were incubated with cumulative concentrations of apremilast (6 nM to 1 μM), apremilast + CGS21680 1μM 15 minutes before apremilast, or cumulative concentrations of CGS21680 alone (6 nM to 1 μM), followed by treatment with lipopolysaccharide (LPS) 1 μM for 20 minutes. Then, intracellular cAMP levels were measured as described under “Materials and methods”. Data represent means ± standard error of the mean of at least three independent experiments. (TIFF 170 kb)