n-3 polyunsaturated fatty acids (PUFAs) inhibit mast cell activation by disrupting FcεRI association with lipid rafts (HYP3P.401)

Abstract INTRODUCTION: n-3 PUFAs can suppress allergic inflammation. We hypothesized that n-3 PUFAs inhibit mast cell (MC) activation through modification of FcεRI association with lipid rafts on plasma membrane. METHODS: Bone marrow-derived MCs (BMMC) were cultivated from C57BL/6 wild-type (WT) and fat-1 transgenic mice which express fatty acid n-3 desaturase and produce endogenous n-3 PUFAs. Exogenous n-3 PUFAs were supplemented to WT BMMC. Degranulation, cysteinyl leukotriene (cys-LT), and tumor necrosis factor (TNF) and chemokine (C-C motif) ligand 2 (CCL2) release were evaluated following FcεRI activation. Lipid rafts were isolated by sucrose gradient centrifugation. FcεRI expression was determined by flow cytometry and western blot analysis. RESULTS: Gas chromatography-mass spectrometry analysis showed increased n-3 PUFA levels in whole cell lysates and lipid raft fractions of fat-1 BMMC compared to WT BMMC and in whole cell lysates of PUFA-supplemented BMMC. n-3 PUFAs inhibited degranulation and cys-LT, TNF and CCL2 production compared to untreated BMMC. n-3 PUFAs did not alter expression of surface or total cell FcεRI. However, n-3 PUFAs suppressed FcεRI localization in lipid rafts of unstimulated cells, and disrupted FcεRI shuttling to rafts in stimulated BMMC. CONCLUSIONS: Our results suggest that n-3 PUFAs inhibit MC activation by disruption of FcεRI localization and shuttling into lipid rafts.