Discovery of aspirin-triggered eicosanoid-like mediators in a Drosophila metainflammation-blood tumor model

Abstract

Epidemiologic studies have linked aspirin's use to a decline in chronic inflammation that underlies many human diseases including some cancers. Aspirin reduces cyclooxygenase-mediated pro-inflammatory prostaglandins, promotes the production of pro-resolution molecules, and triggers the production of anti-inflammatory electrophilic mono-oxygenated (EFOX) lipid mediators. We investigated aspirin's effects in fruit fly models of chronic inflammation. Ectopic Toll/NF-κB and JAK/STAT signaling in mutant D. melanogaster results in overproliferation of hematopoietic blood progenitors resulting in the formation of granuloma-like tumors. Ectopic JAK-STAT signaling also leads to metabolic inflammation. We report that aspirin-treated mutant flies experience reduction in metabolic inflammation, mitosis, ectopic immune signaling, and macrophage infiltration. Moreover, these flies synthesize 13-HODE, and aspirin triggers 13-oxoODE (13-EFOX-L2) production. Providing 13-HODE's precursor linoleic acid, or performing targeted knockdown of transcription factor STAT in inflammatory blood cells, boosts 13-EFOX-L2 levels while decreasing metabolic inflammation. Thus, hematopoietic cells regulate metabolic inflammation in flies, and their effects can be reversed by pharmaceutical or dietary intervention, suggesting deep phylogenetic conservation in animals’ ability to resolve inflammation and repair tissue damage. These findings can help identify novel treatment targets in humans.