NF-κB inhibition by ω-3 fatty acids modulates LPS-stimulated macrophage TNF-α transcription

Abstract

ω-3 Fatty acid (FA) emulsions reduce LPS-stimulated murine macrophage TNF-α production, but the exact mechanism has yet to be defined. The purpose of this study was to determine the mechanism for ω-3 FA inhibition of macrophage TNF-α production following LPS stimulation. RAW 264.7 cells were pretreated with isocaloric emulsions of ω-3 FA (Omegaven), ω-6 FA (Lipovenos), or DMEM and subsequently exposed to LPS. IκB-α and phospho-IκB-α were determined by Western blotting. NF-κB binding was assessed using the electromobility shift assay, and activity was measured using a luciferase reporter vector. RT-PCR and ELISA quantified TNF-α mRNA and protein levels, respectively. Pretreatment with ω-3 FA inhibited IκB phosphorylation and significantly decreased NF-κB activity. Moreover, ω-3-treated cells demonstrated significant decreases in both TNF-α mRNA and protein expression by 47 and 46%, respectively. These experiments demonstrate that a mechanism for proinflammatory cytokine inhibition in murine macrophages by ω-3 FA is mediated, in part, through inactivation of the NF-κB signal transduction pathway secondary to inhibition of IκB phosphorylation.