UC San Diego

Eicosanoids and other bioactive lipid mediators are indispensable regulators of biological processes, as demonstrated by the numerous inflammatory diseases resulting from their dysregulation, including cancer, hyperalgesia, atherosclerosis, and arthritis. Despite their importance, a robust strategy comparable with gene or protein array technology for comprehensively analyzing the eicosanoid metabolome has not been forthcoming. We have developed liquid chromatography-tandem mass spectrometry methodology that quantitatively and comprehensively analyzes the eicosanoid metabolome and utilized this approach to characterize eicosanoid production during experimental Lyme arthritis in mice infected with the bacterium Borrelia burgdorferi. Eicosanoids were extracted throughout infection from the joints of Lyme arthritis-resistant and -susceptible mice and subjected to lipidomic profiling. We identified temporal and quantitative differences between these mouse strains in the production of eicosanoids, which correlated with differences in arthritis development. The eicosanoid biosynthetic enzyme cyclooxygenase (COX)-2 has been implicated in the regulation of Lyme arthritis pathology, and subsequent lipidomic profiling of B. burgdorferi-infected COX-2(-/-) mice identified reductions not only in COX-2 products but, surprisingly, also significant off-target reductions in 5-lipoxygenase metabolites. Our results demonstrate the utility of a comprehensive lipidomic approach for identifying potential contributors to disease pathology and may facilitate the development of more precisely targeted treatment strategies.