Inappropriate, excessive or uncontrolled inflammation contributes to a range of human diseases. Inflammation involves a multitude of cell types, chemical mediators and interactions. The present article will describe nutritional and metabolic aspects of omega-6 (n-6) and omega-3 (n-3) fatty acids and explain the roles of bioactive members of those fatty acid families in inflammatory processes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are n-3 fatty acids found in oily fish and fish oil supplements. These fatty acids are capable of partly inhibiting many aspects of inflammation including leucocyte chemotaxis, adhesion molecule expression and leucocyte–endothelial adhesive interactions, production of eicosanoids like prostaglandins and leukotrienes from the n-6 fatty acid arachidonic acid and production of pro-inflammatory cytokines. In addition, EPA gives rise to eicosanoids that often have lower biological potency than those produced from arachidonic acid, and EPA and DHA give rise to anti-inflammatory and inflammation resolving mediators called resolvins, protectins and maresins. Mechanisms underlying the anti-inflammatory actions of EPA and DHA include altered cell membrane phospholipid fatty acid composition, disruption of lipid rafts, inhibition of activation of the pro-inflammatory transcription factor nuclear factor κB so reducing expression of inflammatory genes and activation of the anti-inflammatory transcription factor peroxisome proliferator-activated receptor γ. Animal experiments demonstrate benefit from EPA and DHA in a range of models of inflammatory conditions. Human trials demonstrate benefit of oral n-3 fatty acids in rheumatoid arthritis and in stabilizing advanced atherosclerotic plaques. Intravenous n-3 fatty acids may have benefits in critically ill patients through reduced inflammation. The anti-inflammatory and inflammation resolving actions of EPA, DHA and their derivatives are of clinical relevance.
The Holliday junction. The structure of the Holliday junction is highly variable, being adaptable to its biological function in recombination and to applications in biomolecular engineering. This image shows the how the junction extends from simple schematics to crystal structures as DNA only and in protein complexes. In addition, the junction has been exploited as an element in the design of 2-D and 3-D lattices in crystal engineering and more complex images and shapes through DNA origami. In this issue of Biochemical Society Transactions, P. Shing Ho reviews some interesting recent research on the Holliday junction; for details see pages 1149–1158.
Omega-3 fatty acids and inflammatory processes: from molecules to man
Philip C. Calder; Omega-3 fatty acids and inflammatory processes: from molecules to man. Biochem Soc Trans 15 October 2017; 45 (5): 1105–1115. doi: https://doi.org/10.1042/BST20160474
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