title: Anti-inflammatory effect of pyroglutamyl-leucine on lipopolysaccharide-stimulated RAW 264.7 macrophages.
abstract: OBJECTIVE
  Food-derived peptides have been reported to yield a variety of health promoting activities. Pyroglutamyl peptides are contained in the wheat gluten hydrolysate. In the present study, we investigated the effect of pyroglutamyl dipeptides on the lipopolysaccharide (LPS)-induced inflammation in macrophages.
  
  
  METHODS
  RAW 264.7 macrophages were treated with LPS and various concentrations of pyroglutamyl-leucine (pyroGlu-Leu), -valine (pyroGlu-Val), -methionine (pyroGlu-Met), and -phenylalanine (pyroGlu-Phe). Cell viability/proliferation and various inflammatory parameters were measured by the established methods including ELISA and western blotting. The binding of fluorescein isothiocyanate-labeled LPS to RAW 264.7 cells was also measured fluorescently.
  
  
  RESULTS
  All the tested dipeptides significantly inhibited the secretion of nitric oxide, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 from LPS-stimulated RAW 264.7 macrophages. Above all, pyroGlu-Leu inhibited the secretion of all these inflammatory mediators even at the lowest dose (200μg/ml). PyroGlu-Leu dose-dependently suppressed IκBα degradation and MAPK (JNK, ERK, and p38) phosphorylation in LPS-stimulated RAW 264.7 cells. On the other hand, it did not affect the binding of LPS to the cell surface.
  
  
  CONCLUSIONS
  Our results indicated that pyroGlu-Leu inhibits LPS-induced inflammatory response via the blocking of NF-κB and MAPK pathways in RAW 264.7 macrophages.
authors.affiliation: Laboratory of Food and Nutrition, Division of Applied Biochemistry, Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Hirai
authors.affiliation: Laboratory of Food and Nutrition, Division of Applied Biochemistry, Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Horii
authors.affiliation: Laboratory of Food and Nutrition, Division of Applied Biochemistry, Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Matsuzaki
authors.affiliation: Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Ono
authors.affiliation: Health Care Research Center, R&D Division, Nisshin Pharma Inc., 5-3-1 Tsurugaoka, Fujimino-City, Saitama 356-8511, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shimmura
authors.affiliation: Division of Applied Life Sciences, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sato
authors.affiliation: Laboratory of Food and Nutrition, Division of Applied Biochemistry, Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan. Electronic address: egashira@faculty.chiba-u.jp.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Egashira
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D004151:Dipeptides / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D007249:Inflammation / Q000188:drug therapy* / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects* / Q000473:pathology; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011761:Pyrrolidonecarboxylic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D004151:Dipeptides; D018836:Inflammation Mediators; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; C041765:pyroglutamylleucine; D009569:Nitric Oxide; D011761:Pyrrolidonecarboxylic Acid
keywords: Inflammation; Macrophage; Pyroglutamyl peptide; Pyroglutamyl-leucine; Wheat gluten hydrolysate