title: Inhibition of NF-κB-dependent cytokine and inducible nitric oxide synthesis by the macrocyclic ellagitannin oenothein B in TLR-stimulated RAW 264.7 macrophages.
abstract: Immunomodulatory effects of oenothein B (1), a macrocyclic ellagitannin from various Onagraceae species, have been described previously. However, the mechanisms underlying the anti-inflammatory activity of 1 have not been fully clarified. The effects of 1 were investigated on inducible nitric oxide synthase, TLR-dependent and TLR-independent signal transduction cascades, and cytokine expression using murine macrophages (RAW 264.7). Compound 1 (10-60 μg/mL) reduced NO production, iNOS mRNA, and iNOS protein levels in a dose-dependent manner, without inhibition of iNOS enzymatic activity. It reduced the binding of the NF-κB p50 subunit to the biotinylated-consensus sequence and decreased nuclear p65 translocation. Gallic acid as a subunit of the macrocyclic ellagitannin 1 showed a far lower inhibitory activity. Nitric oxide production was reduced by 1 after stimulation using TLR2 (Pam2CSK4) and TLR4 (Kdo2) agonists, but this compound did not inhibit inducible nitric oxide synthesis after stimulation using interferon-gamma. IL-1beta, IL-6, and TNF-alpha mRNA synthesis was clearly reduced by the addition of 1. Oenothein B (1) inhibits iNOS after stimulation with LPS, TLR2, and TLR4 agonists via inhibition of TLR/NF-κB-dependent inducible nitric oxide and cytokine synthesis independent from IFN-gamma/JAK/STAT pathways. The full molecular structure of this macrocyclic ellagitannin seems to be required for its immunomodulatory actions.
authors.affiliation: Institute for Physiology, Center for Physiology and Pharmacology,  Medical University of Vienna , Austria.
authors.forename: Diethart
authors.initials: D
authors.lastname: Schmid
authors.forename: Miriam
authors.initials: M
authors.lastname: Gruber
authors.forename: Carolin
authors.initials: C
authors.lastname: Piskaty
authors.forename: Florian
authors.initials: F
authors.lastname: Woehs
authors.forename: Andreas
authors.initials: A
authors.lastname: Renner
authors.forename: Zsofia
authors.initials: Z
authors.lastname: Nagy
authors.forename: Alexander
authors.initials: A
authors.lastname: Kaltenboeck
authors.forename: Thomas
authors.initials: T
authors.lastname: Wasserscheid
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Bazylko
authors.forename: Anna K
authors.initials: AK
authors.lastname: Kiss
authors.forename: Thomas
authors.initials: T
authors.lastname: Moeslinger
mesh_terms: D000818:Animals; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000494:pharmacology*; D007155:Immunologic Factors / Q000737:chemistry / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects*; D051379:Mice; D015394:Molecular Structure; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D051193:Toll-Like Receptors / Q000378:metabolism*; D051996:Transcription Factor RelA
chemical_list: D047348:Hydrolyzable Tannins; D007155:Immunologic Factors; D008070:Lipopolysaccharides; D016328:NF-kappa B; D051193:Toll-Like Receptors; D051996:Transcription Factor RelA; C080077:oenothein B; D009569:Nitric Oxide