Construction of reporter yeasts for mouse aryl hydrocarbon receptor ligand activity

Kawanishi, Michihiro; Sakamoto, Michiyo; Ito, Akihide; Kishi, K.; Yagi, Takashi

doi:10.1016/s1383-5718(03)00174-8

Cited by 64 publications

(60 citation statements)

References 22 publications

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“…Yet compared with the mAHR b , the hAHR demonstrated a higher relative ligand binding affinity for quercetin and indirubin specifically. Indirubin has been shown previously to be 35-to 140-fold more potent at inducing hAHR than mAHR activity in a yeast reporter system (Kawanishi et al, 2003). In these competitive ligand binding studies, gene expression analysis and EMSA analysis all suggest that indirubin is a highpotency, high-affinity hAHR-specific ligand.…”

Section: Discussionmentioning

confidence: 76%

Ligand Selectivity and Gene Regulation by the Human Aryl Hydrocarbon Receptor in Transgenic Mice

Flaveny¹,

Murray²,

Chiaro³

et al. 2009

Mol Pharmacol

119

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The aryl hydrocarbon receptor (AHR) is a ligand-inducible transcription factor that displays interspecies differences with the human and mouse AHR C-terminal region sequences sharing only 58% amino acid sequence identity. Compared with the mouse AHR (mAHR), the human AHR (hAHR) displays ϳ10-fold lower relative affinity for prototypical AHR ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, which has been attributed to the amino acid residue valine 381 (alanine 375 in the mAHR) in the ligand binding domain of the hAHR. We investigated whether the 10-fold difference in ligand-binding affinity between the mAHR and hAHR would be observed with a diverse range of AHR ligands. To test this hypothesis, ligand binding assays were performed using the photo-affinity ligand 2-azido-3-[125 I]iodo-7,8-dibromodibenzo-p-dioxin and liver cytosol isolated from hepatocyte-specific transgenic hAHR mice and C57BL/6J mice. It is noteworthy that competitive ligand-binding assays revealed that, compared with the mAHR, the hAHR has a higher relative affinity for certain compounds, including indirubin [(2Z)-2,3-biindole-2,3 (1ЈH,1ЈH)-dione and quercetin (2-(3,4dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one]. Electrophoretic mobility shift assays revealed that indirubin was more efficient at transforming the hAHR compared with the mAHR. Indirubin was also a more potent inducer of Cyp1a1 expression in transgenic hAHR mouse hepatocytes compared with C57BL/6J mouse hepatocytes. These observations suggest that indirubin is a potent hAHR ligand that is able to selectively bind to and activate the hAHR. These discoveries imply that there may be a significant degree of structural divergence between mAHR and hAHR ligands and highlights the importance of the hAHR transgenic mouse as a model to study the hAHR in vivo.

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Section: Discussionmentioning

confidence: 76%

Ligand Selectivity and Gene Regulation by the Human Aryl Hydrocarbon Receptor in Transgenic Mice

Flaveny¹,

Murray²,

Chiaro³

et al. 2009

Mol Pharmacol

119

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“…Interestingly, indirubin is the active ingredient of a traditional Chinese medicine recipe, Danggui Longhui Wan, used to treat various diseases including chronic myelocytic leukemia (review in Xiao et al, 2002). Besides CDKs, indirubins were found to target glycogen synthase kinase-3 (GSK-3) (Leclerc et al, 2001), glycogen phosphorylase b (Kosmopoulou et al, 2004) and the aryl hydrocarbon receptor (AhR), also known as the dioxin receptor (Adachi et al, 2001;Kawanishi et al, 2003). Aryl hydrocarbon receptor mediates the effects of many xenobiotics such as dioxin and indole-containing compounds (review in Denison and Nagy, 2003).…”

Section: Introductionmentioning

confidence: 99%

7-Bromoindirubin-3′-oxime induces caspase-independent cell death

Ribas

Bettayeb²,

Ferandin³

et al. 2006

Oncogene

102

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“…OPUH (Osaka Prefecture University human AhR-assay yeast) and OPUM (Osaka Prefecture University mouse AhR-assay yeast) are the reporter assay yeast strains that express human and mouse AhR/Arnt, respectively, controlled by XRE, which were established in our previous study (Kawanishi et al, 2003). The assay in the present study was performed according to the procedures described in the previous report.…”

Section: Methodsmentioning

confidence: 99%

Microbial Metabolites of Omeprazole Activate Murine Aryl Hydrocarbon Receptor In Vitro and In Vivo

2014

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Omeprazole (OME), a proton pump inhibitor used to treat gastritis, is also an aryl hydrocarbon receptor (AhR) activator. OME activates AhR in human hepatocytes and hepatoma cells, but not in mice in vivo or in vitro. We recently discovered that this species-specific difference results from a difference in a few amino acids in the ligand-binding domain of AhR. However, OME activates both mouse and human AhRs in the yeast reporter assay system. Nevertheless, the cause of this discrepancy in OME responses remains unknown. Here, we report that CYP1A1 mRNA expression in mouse cecum was elevated after OME administration, although the mouse is regarded as an OME-unresponsive animal. Using the yeast reporter assay system with human and murine AhRs, we found AhR agonist-like activity in the cecal extracts of OME-treated mice.We speculated that OME metabolites produced by cecal bacteria might activate murine AhRs in vivo. In high-performance liquid chromatography (HPLC) analysis, AhR agonist-like activity of cecal bacterial culture and cecal extracts were detected at the same retention time. AhR agonist-like activity was also detected in the HPLC fractions of yeast culture media containing OME. This unknown substance could induce reporter gene expression via mouse and human AhRs. The agonist-like activity of the OME metabolite was reduced by concomitant a-naphthoflavone exposure. These results indicate that a yeast-generated OME metabolite elicited the response of mouse AhR to OME in the yeast system, and that bacterial OME metabolites may act as AhR ligands in human and mouse intestines.

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Construction of reporter yeasts for mouse aryl hydrocarbon receptor ligand activity

Cited by 64 publications

References 22 publications

Ligand Selectivity and Gene Regulation by the Human Aryl Hydrocarbon Receptor in Transgenic Mice

Ligand Selectivity and Gene Regulation by the Human Aryl Hydrocarbon Receptor in Transgenic Mice

7-Bromoindirubin-3′-oxime induces caspase-independent cell death

Microbial Metabolites of Omeprazole Activate Murine Aryl Hydrocarbon Receptor In Vitro and In Vivo

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