title: Indigo Naturalis ameliorates murine dextran sodium sulfate-induced colitis via aryl hydrocarbon receptor activation.
abstract: BACKGROUND
  Indigo Naturalis (IN) is used as a traditional herbal medicine for ulcerative colitis (UC). However, the mechanisms of action of IN have not been clarified. We aimed to evaluate the efficacy of IN for ameliorating colonic inflammation. We further investigated the mechanisms of action of IN.
  
  
  METHODS
  Colitis severity was assessed in dextran sodium sulfate-induced colitis and trinitrobenzene sulfonic acid-induced colitis models with or without the oral administration of IN or indigo, which is a known major component of IN. Colonic lamina propria (LP) mononuclear cells isolated from IN-treated mice were analyzed with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and flow cytometry. LP and splenic mononuclear cells cultured in vitro with IN or indigo were also analyzed. The role of the candidate receptor for indigo, the aryl hydrocarbon receptor (AhR), was analyzed using Ahr-deficient mice.
  
  
  RESULTS
  Colitis severity was significantly ameliorated in the IN and indigo treatment groups compared with the control group. The mRNA expression levels of interleukin (Il)-10 and Il-22 in the LP lymphocytes were increased by IN treatment. The treatment of splenocytes with IN or indigo increased the expression of anti-inflammatory cytokines and resulted in the expansion of IL-10-producing CD4+T cells and IL-22-producing CD3-RORγt+cells, but not CD4+Foxp3+regulatory T cells. The amelioration of colitis by IN or indigo was abrogated in Ahr-deficient mice, in association with diminished regulatory cytokine production.
  
  
  CONCLUSIONS
  IN and indigo ameliorated murine colitis through AhR signaling activation, suggesting that AhR could be a promising therapeutic target for UC.
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Kawai
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan. hiijima@gh.med.osaka-u.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Iijima
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Shinzaki
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.|Department of Inflammatory Bowel Disease, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hiyama
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Araki
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Shuko
authors.initials: S
authors.lastname: Iwatani
authors.affiliation: Department of Gastroenterology and Hepatology, Sumitomo Hospital, Osaka, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Shiraishi
authors.affiliation: Department of Gastroenterology and Hepatology, Sumitomo Hospital, Osaka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Mukai
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.|Department of Gastroenterology and Hepatology, Higashiosaka City General Hospital, Higashiosaka, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tsujii
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Motooka
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Iida
authors.affiliation: Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Takehara
mesh_terms: D000818:Animals; D017252:CD3 Complex / Q000378:metabolism; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D002478:Cells, Cultured; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D016264:Dextran Sulfate; D004365:Drugs, Chinese Herbal / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D007203:Indigo Carmine / Q000494:pharmacology* / Q000627:therapeutic use; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D007378:Interleukins / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D018345:Mice, Knockout; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000172:deficiency / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D012720:Severity of Illness Index; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism; D014302:Trinitrobenzenesulfonic Acid; D000097043:Interleukin-22
chemical_list: D017252:CD3 Complex; D016264:Dextran Sulfate; D004365:Drugs, Chinese Herbal; D051858:Forkhead Transcription Factors; D007203:Indigo Carmine; D016753:Interleukin-10; D053645:Interleukin-2 Receptor alpha Subunit; D007378:Interleukins; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014302:Trinitrobenzenesulfonic Acid; D000097043:Interleukin-22; C498833:Foxp3 protein, mouse; C508018:Il2ra protein, mouse; C530990:Qingdai compound
keywords: Aryl hydrocarbon receptor; Indigo; Indigo Naturalis; Inflammatory bowel disease; Ulcerative colitis