Adenosine, prostaglandin E2, or increased intracellular cyclic AMP concentration each elicit potent anti-inflammatory events in human neutrophils by inhibiting functions such as phagocytosis, superoxide production, adhesion and cytokine release. However, the endogenous molecular pathways mediating these actions are poorly understood. In the present study, we examined their impact on the gene expression profile of stimulated neutrophils. We have identified a set of genes that may be part of important resolution pathways that interfere with cell activation. Identification of these pathways will improve understanding of the capacity of tissues to terminate inflammatory responses and contribute to the development of therapeutic strategies based on endogenous resolution

Neutrophils were resuspended at a concentration of 25 x 106 cells/ml in Hank's balanced salt solution (HBSS; 37°C) containing 1% fetal bovine serum, 10 mM HEPES pH 7.4, 1,6 mM Ca2+ and no Mg2+. Adenosine deaminase (ADA; 0.1U/mL) was added to cell suspensions 20 min prior to stimulation. Where mentioned, PGE2, CGS 21680, RO 20-1724 and forskolin, dissolved in DMSO, were added to cell suspensions 10 min before stimulation. The final organic solvent concentration was identical in all samples and did not exceed 0.1% (v/v). Neutrophils were stimulated with a mixture of LPS (100 ng/mL), GM-CSF (1.4 nM), TNF-? (100 ng/mL), fMLP (100 nM) and IL-1? (30 nM) for 30 min at 37oC. These experiments were performed 5 times in identical conditions, each time with a different donor.