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Conjugated Linoleic Acids Can Change Phagocytosis of Human Monocytes/Macrophages by Reduction in Cox-2 Expression

Stachowska, Ewa, Baśkiewicz-Masiuk, Magdalena, Dziedziejko, Violetta, Adler, Grażyna, Bober, Joanna, Machaliński, Bogusław, Chlubek, Dariusz
Lipids 2007 v.42 no.8 pp. 707-716
dietary fat, conjugated linoleic acid, immune response, phagocytosis, monocytes, macrophages, cultured cells, prostaglandin synthase, gene expression regulation, messenger RNA, protein content, prostaglandins, human health
Prostaglandin E₂ produced endogenously (by cyclooxygenases) can regulate macrophage phagocytosis. Cyclooxygenase activity reduction (mainly through inhibition of inducible Cox-2) can induce PGE₂ synthesis depression and can activate the phagocytosis process. There are no reports in the literature explaining whether conjugated linoleic acid dienes (trans-10, cis-12 CLA and cis-9, trans-11 CLA) modify the phagocytic activity of human macrophages. For the purpose of this study, monocytes were isolated from venous blood, incubated for 7 days with 30 μM CLAs, and then (in some experiments) LPS (1 μg/mL) was added to the medium. Subsequently, monocyte/macrophage phagocytosis, NF-κB transcription factor activity, Cox-2 and PPARγ mRNA expression (and the amounts of Cox-2 and PPARγ proteins) and PGE₂ synthesis were determined. Both CLA isomers increased macrophage phagocytosis through inhibition of Cox-2 expression (might by inactivation the NF-κB pathway). The inhibition of mRNA Cox-2 expression contributed (particularly with respect to trans-10, cis-12 CLA) to a decrease in protein Cox-2 synthesis and to reduction of prostaglandin E₂ content in the cell. The inhibition of PGE₂ synthesis (by CLA treatment) enhanced the phagocytosis process in macrophages.