title: Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ.
abstract: The retinoic acid receptor-related orphan receptors α and γ (RORα and RORγ), are key regulators of helper T (Th)17 cell differentiation, which is involved in the innate immune system and autoimmune disorders. In this study, we investigated the effects of isoflavones on RORα/γ activity and the gene expression of interleukin (IL)-17, which mediates the function of Th17 cells. In doxycycline-inducible CHO stable cell lines, we found that four isoflavones, biochanin A (BA), genistein, formononetin, and daidzein, enhanced RORα- or RORγ-mediated transcriptional activity in a dose-dependent manner. In an activation assay of the Il17a promoter using Jurkat cells, these compounds enhanced the RORα- or RORγ-mediated activation of the Il17a promoter at concentrations of 1 × 10(-6)M to 1 × 10(-5)M. In mammalian two-hybrid assays, the four isoflavones enhanced the interaction between the RORα- or RORγ-ligand binding domain and the co-activator LXXLL peptide in a dose-dependent manner. In addition, these isoflavones potently enhanced Il17a mRNA expression in mouse T lymphoma EL4 cells treated with phorbol myristate acetate and ionomycin, but showed slight enhancement of Il17a gene expression in RORα/γ-knockdown EL4 cells. Immunoprecipitation and immunoblotting assays also revealed that BA enhanced the interaction between RORγt and SRC-1, which is a co-activator for nuclear receptors. Taken together, these results suggest that the isoflavones have the ability to enhance IL-17 gene expression by stabilizing the interactions between RORα/γ and co-activators. This also provides the first evidence that dietary chemicals can enhance IL-17 gene expression in immune cells.
authors.affiliation: Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819, Japan. Electronic address: kojima@iph.pref.hokkaido.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kojima
authors.affiliation: National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
authors.forename: Yukimasa
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Muromoto
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hirao
authors.affiliation: Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeuchi
authors.affiliation: National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
authors.forename: Anton M
authors.initials: AM
authors.lastname: Jetten
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D016466:CHO Cells; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D005786:Gene Expression Regulation; D019833:Genistein / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D020381:Interleukin-17 / Q000235:genetics / Q000378:metabolism*; D007529:Isoflavones / Q000494:pharmacology*; D019169:Jurkat Cells; D051379:Mice; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1 / Q000235:genetics / Q000378:metabolism*; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D058504:Th17 Cells / Q000187:drug effects / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D007529:Isoflavones; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C007768:formononetin; C004742:daidzein; D019833:Genistein; C004541:biochanin A
keywords: Interleukin 17; Isoflavone; Luciferase assay; Retinoic acid receptor-related orphan receptor; Th17