Isoflavones enhance interleukin-17 gene expression via retinoic acid receptor-related orphan receptors α and γ. (2nd March 2015)

• Record Type: Journal Article
• Authors: Kojima, Hiroyuki; Takeda, Yukimasa; Muromoto, Ryuta; Takahashi, Miki; Hirao, Toru; Takeuchi, Shinji; Jetten, Anton M.; Matsuda, Tadashi
• Is Part Of: Toxicology. Volume 329(2015)
• Page Start: 32
• Page End: 39
• Publication Date: 2015-03-02
• Subjects: AF activation function -- ANOVA analysis of variance -- BA biochanin A -- CD-FBS charcoal-dextran treated FBS -- CHO Chinese hamster ovary -- CNS conserved noncoding sequence -- DMEM Dulbecco's modified Eagle's medium -- DMSO dimethyl sulfoxide -- DZ daidzein -- EAE experimental autoimmune encephalomyelitis -- EDTA ethylenediamine tetra-acetic acid -- FBS fetal bovine serum -- FGF fibroblast growth factor -- FN formononetin -- G6Pase glucose-6-phosphatase -- Gal galactocidase -- GE genistein -- HRP horse-radish peroxidase -- IL-17 interleukin 17 -- LBD ligand-binding domain -- LUC luciferase -- NCOA1 nuclear receptor co-activator-1 -- NCOR1 nuclear receptor co-repressor-1 -- NR nuclear receptor -- PCR polymerase chain reaction -- PMA phorbol 12-myristate 13-acetate -- RIP140 receptor interacting protein 140 -- ROR retinoic acid receptor-related orphan receptor -- RORE ROR response element -- PGC-1α peroxisome proliferator-activated receptor γ co-activator-1α -- RT-PCR reverse transcriptase-PCR -- shRNA short hairpin RNA -- SD standard deviation -- SDS sodium dodecyl sulfate -- SDS-PAGE SDS-polyacrylamide-gel electrophoresis -- SEM standard error of mean -- SRC-1 steroid receptor co-activator-1 -- Th17 T-helper 17 -- TRE tetracycline responsive element -- UAS upstream activating sequence; Interleukin 17 -- Isoflavone -- Luciferase assay -- Retinoic acid receptor-related orphan receptor -- Th17; Toxicology -- Periodicals; Chemicals -- Physiological effect -- Periodicals; 615.9005
• DOI: 10.1016/j.tox.2015.01.007
• Languages: English
• ISSNs: 0300-483X

Abstract

Highlights: Nuclear receptors, RORα and RORγ, are key regulators of Th17 cell differentiation. Isoflavones have RORα/γ agonistic activities. Isoflavones enhance the interaction of RORα/γ with co-activator. These compounds enhance the expression of Il17a mRNA in mouse EL4 cells. Dietary isoflavones can act as modulators of Il17a expression via RORα/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.