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Dietary Tryptophan Alleviates Dextran Sodium Sulfate-Induced Colitis Through Aryl Hydrocarbon Receptor in Mice

Jahidul Islam, Shoko Sato, Kouichi Watanabe, Takaya Watanabe, Ardiansyah, Keisuke Hirahara, Yukihide Aoyama, Shuhei Tomita, Hisashi Aso, Michio Komai, Hitoshi Shirakawa

J Nutr Biochem. 2017 Apr;42:43-50.

PMID: 28113104

Abstract:

Ulcerative colitis is the typical progression of chronic inflammatory bowel disease. Amino acids, particularly tryptophan, have been reported to exert a protective effect against colitis induced by dextran sodium sulfate (DSS), but the precise underlying mechanisms remain incompletely clarified. Tryptophan metabolites are recognized to function as endogenous ligands for aryl hydrocarbon receptor (Ahr), which is a critical regulator of inflammation and immunity. Thus, we conducted this study to investigate whether dietary tryptophan supplementation protects against DSS-induced colitis by acting through Ahr. Female wild-type (WT) and Ahr-deficient (knockout; KO) mice (10-12 weeks old) were divided into four groups and fed either a control or 0.5% tryptophan diet. The tryptophan diet ameliorated DSS-induced colitis symptoms and severity in WT mice but not in KO mice, and the diet reduced the mRNA expression of Il-6, Tnfα, Il-1β and the chemokines Ccl2, Cxcl1 and Cxcl2 in the WT groups. Furthermore, Il-22 and Stat3 mRNA expression in the colon was elevated in WT mice fed with the tryptophan diet, which mainly protected epithelial layer integrity, and Ahr also modulated immune homeostasis by regulating Foxp3 and Il-17 mRNA expression. These data suggest that tryptophan-containing diet might ameliorate DSS-induced acute colitis and regulate epithelial homeostasis through Ahr. Thus, tryptophan could serve as a promising preventive agent in the treatment of ulcerative colitis.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP7757826-B Sodium sulfate Sodium sulfate 7757-82-6 Price
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