Molecular Nutrition & Food Research 2016-02-01

Docosahexaenoic acid inhibits inflammation via free fatty acid receptor FFA4, disruption of TAB2 interaction with TAK1/TAB1 and downregulation of ERK-dependent Egr-1 expression in EA.hy926 cells.

Kai-Li Liu, Ya-Chen Yang, Hsien-Tsung Yao, Ting-Wen Chia, Chia-Yang Lu, Chien-Chun Li, Henry J Tsai, Chong-Kuei Lii, Haw-Wen Chen

Index: Mol. Nutr. Food. Res. 60 , 430-43, (2016)

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Abstract

Inflammation is intimately associated with many cardiovascular events and docosahexaenoic acid (DHA) has been shown to protect against CVD. Egr-1 has emerged as a key regulator in the development of atherosclerosis. Free fatty acid receptor 4 (FFA4) is an n-3 FA membrane receptor. Tumor necrosis factor alpha (TNF-α) is an inflammatory mediator and transforming growth factor-β-activated kinase 1 (TAK1) is essential in the TNF-α-mediated activation of NF-κB. We examined the mechanisms underlying DHA inhibition of inflammation in human EA.hy926 cells.TNF-α markedly induced the interaction between TAK1 binding protein (TAB) 2 and TAK1/TAB1, the phosphorylation of ERK, p38 MAPK and Akt, the expression of Egr-1 and ICAM-1, and HL-60 (monocyte-like) cell adhesion. Pretreatment with DHA attenuated TNF-α-induced phosphorylation of ERK, expression of Egr-1 and ICAM-1 and HL-60 cell adhesion. Transfection with siFFA4 reversed the DHA-mediated inhibition of TNF-α-induced Egr-1 and ICAM-1 expression, HL-60 cell adhesion and NF-κB and DNA-binding activity.Our results suggest that the anti-inflammatory effect of DHA on the endothelium is at least partially linked to FFA4, disruption of TAB2 interaction with TAK1/TAB1 and downregulation of ERK-dependent Egr-1 and ICAM-1 expression, which leads to less HL-60 cell adhesion to TNF-α-stimulated EA.hy926 cells.© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.