title: Polyunsaturated fatty acids block dendritic cell activation and function independently of NF-kappaB activation.
abstract: Polyunsaturated fatty acids (PUFAs) modulate immune responses leading to clinically significant beneficial effects in a variety of inflammatory disorders. PUFA effects on T cells have been extensively studied, but their influence on human dendritic cells (DCs), which are the most potent antigen-presenting cells and play a key role in initiating immune responses, has not been elucidated so far. Here we show that PUFAs of the n-3 and n-6 series (arachidonic and eicosapentaenoic acid) affect human monocyte-derived DC differentiation and inhibit their activation by LPS, resulting in altered DC surface molecule expression and diminished cytokine secretion. Furthermore, the potency to stimulate T cells was markedly inhibited in PUFA-treated DCs. The PUFA-mediated block in LPS-induced DC activation is reflected by diminished TNF-alpha, IL-12p40, CD40, and COX-2 mRNA levels. Strikingly, typical LPS-induced signaling events such as degradation of IkappaB and activation of NF-kappaB were not affected by PUFAs, even though DC membrane lipid composition was markedly altered. Arachidonic and eicosapentaenoic acid both altered DC prostaglandin production, but inhibitors of cyclooxygenases and lipoxygenases did not abolish PUFA effects, indicating that the observed PUFA actions on DCs were independent of autoregulation via eicosanoids. These data demonstrate a unique interference with DC activation and function that could significantly contribute to the well known anti-inflammatory effects of PUFAs.
authors.affiliation: Clinical Divisions of Endocrinology and Metabolism, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Zeyda
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Säemann
authors.forename: Karl M
authors.initials: KM
authors.lastname: Stuhlmeier
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Mascher
authors.forename: Peter N
authors.initials: PN
authors.lastname: Nowotny
authors.forename: Gerhard J
authors.initials: GJ
authors.lastname: Zlabinger
authors.forename: Werner
authors.initials: W
authors.lastname: Waldhäusl
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Stulnig
mesh_terms: D015415:Biomarkers; D002454:Cell Differentiation / Q000502:physiology*; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008084:Lipoxygenase / Q000378:metabolism; D008213:Lymphocyte Activation; D009000:Monocytes / Q000166:cytology; D016328:NF-kappa B / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016207:Cytokines; D005231:Fatty Acids, Unsaturated; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D008084:Lipoxygenase; D011451:Prostaglandin-Endoperoxide Synthases