AP-1-independent NFAT signaling maintains follicular T cell function in infection and autoimmunity.

Coordinated gene expression programs enable development and function of T cell subsets. Follicular helper T (Tfh) cells coordinate humoral immune responses by providing selective and instructive cues to germinal center B cells. Here, we show that AP-1-independent NFAT gene expression, a program associated with hyporesponsive T cell states like anergy or exhaustion, is also a distinguishing feature of Tfh cells.

12/15-Lipoxygenase Regulates IL-33-Induced Eosinophilic Airway Inflammation in Mice.

Dysregulated fatty acid metabolism is clinically associated with eosinophilic allergic diseases, including severe asthma and chronic rhinosinusitis. This study aimed to demonstrate the role of 12/15-lipoxygenase (12/15-LOX) in interleukin (IL)-33-induced eosinophilic airway inflammation; to this end, we used 12/15-LOX-deficient mice, which displayed augmented IL-33-induced lung inflammation, characterized by an increased number of infiltrated eosinophils and group 2 innate lymphoid cells (ILC2s) in the airway. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipidomics revealed that the levels of a series of 12/15-LOX-derived metabolites were significantly decreased, and application of 14(S)-hydroxy docosahexaenoic acid (HDoHE), a major 12/15-LOX-derived product, suppressed IL-33-mediated eosinophilic inflammation in 12/15-LOX-deficient mice.

Identification of 14,20-dihydroxy-docosahexaenoic acid as a novel anti-inflammatory metabolite.

Docosahexaenoic acid (DHA) exhibits anti-inflammatory activity related to some of its oxygenated metabolites, such as D-series resolvins, protectin and maresin. Here, we analysed the lipids in inflammatory exudates using liquid chromatography-tandem mass spectrometry and identified a novel DHA metabolite, 14,20-dihydroxy-DHA (14,20-diHDHA) and showed that it is biosynthesized by eosinophils through the 12/15-lipoxygenase pathway. The chemical structure of the dominant 14,20-diHDHA isomer, which is endogenously biosynthesized by eosinophils, was identified as 14S,20R-diHDHA using chemically synthesized stereoisomers.

Total synthesis and bioactivity of resolvin E2.

Resolvin E2 is a potent anti-inflammatory compound, derived from eicosapentaenoic acid. The efficient total synthesis of resolvin E2 by taking advantage of its intrinsic pseudoenantiomeric substructures is reported. The synthetic resolvin E2 proved to be biologically active in blocking neutrophil infiltration and reducing proinflammatory cytokines in the acute peritonitis model.