Dietary ω-3 fatty acids and their influence on inflammation via Toll-like receptor pathways

Dietary intake of long-chain, highly unsaturated omega-3 fatty acids (FAs) is considered indispensable for humans. The omega-3 FAs have been known to be anti-inflammatory and immunomodulatory dietary factors; however, the modes of action on pathogen recognition receptors (PRRs) and downstream signaling pathways have not been fully elucidated. Dietary sources contain various amounts of omega-3 long-chain fatty acids (LCFAs) of different lengths and the association between intake of these polyunsaturated fatty acids (PUFAs) with underlying mechanisms of various immune-related disorders can be of great interest. The potential anti-inflammatory role for omega-3 LCFAs can be explained by modification of lipid rafts, modulation of inflammatory mediators such as cytokines and PRRs. Toll-like receptors (TLRs) are a group of PRRs that play an important role in the recognition of bacterial infections and omega-3 FAs have been implicated in the modulation of downstream signaling of TLR-4, an important receptor for recognition of gram-negative bacteria. The omega-3 FAs docosahexaenoic acid and eicosapentaenoic acid have been investigated in vivo and in vitro for their effects on the nuclear factor-KB activation pathway. Identification of the effects of omega-3 FAs on other key molecular factors like prostaglandins and leukotrienes and their signals may help the recognition and development of medicines to suppress the main mediators and turn on the expression of anti-inflammatory cytokines and nuclear receptors. (C) 2020 Elsevier Inc. All rights reserved.