Impact of Anti-Inflammatory Agents on the Gene Expression Profile of Stimulated Human Neutrophils: Unraveling Endogenous Resolution Pathways

Abstract

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. Purified blood neutrophils from healthy donors were stimulated with a cocktail of inflammatory agonists in the presence of at least one of the following anti-inflammatory agents: adenosine A2A receptor agonist CGS 21680, prostaglandin E2, cyclic-AMP-elevating compounds forskolin and RO 20-1724. Total RNA was analyzed using gene chips and real-time PCR. Genes encoding transcription factors, enzymes and regulatory proteins, as well as secreted cytokines/chemokines showed differential expression. We identified 15 genes for which the anti-inflammatory agents altered mRNA levels. The agents affected the expression profile in remarkably similar fashion, suggesting a central mechanism limiting cell activation. 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.

To the heart of the APS puzzle

“…9 Therefore, the findings reported by Ortona et al in this issue 5 have identified vimentin/cardiolipin as a new APS-related antigen. This antigen has limited specificitybecause it is also antigenic in patients with systemic lupus erythematosus and rheumatoid arthritis.…”

“…In this issue, Ortona and colleagues have shown that affinity-purified antivimentin/cardiolipin antibodies isolated from seronegative patient samples can also induce IRAK1 phosphorylation (primarily coupled to secretion of the cytokine tumor necrosis factor ␣), a phenomenon which was not observed in incubations with purified antivimentin antibodies. 5 Therefore, these experiments (1) illustrate the dependence on phospholipids for the reaction, and (2) couple vimentin via IRAK to endothelial cell activation pathways, similar to those activated via TLRs by antiphospholipid anti-␤ 2 GPI antibodies. 7 Phosphorylation of IRAK1 triggered NF-B activation leads to transcriptional activation, similar to NF-B activation upon LPS stimulation.…”

“…Vimentin displayed phospholipidbinding properties and strongly interacted with cardiolipin; it was also found to be present on the endothelial cell surface. 5 More importantly, the authors found that more than 90% of APS patients and approximately half of the seronegative APS patients had antivimentin/cardiolipin immunoglobulin G antibodies. These antibodies were present in sera from patients with arterial and venous thrombosis, as well as with pregnancy morbidity.…”

“…5 By autoantibody screening via a proteomic approach and by using as an antigen source the cell-surface membrane proteins of endothelial cells, they identified endothelial cell vimentin as a protein, recognized by patient autoantibodies. Vimentin displayed phospholipidbinding properties and strongly interacted with cardiolipin; it was also found to be present on the endothelial cell surface.…”

“…1,5 One study noted that CMVspecific T cells are driven toward replicative exhaustion suggesting that defects in these cells may develop as a result of continuous viral reactivation. 6 Perhaps the expanded cells themselves have the negative impact.…”