Molecular mechanism of the aryl hydrocarbon receptor activation by the fungicide iprodione in rainbow trout (Oncorhynchus mykiss) hepatocytes
| Autor: | Silvia Frigerio, Enzo Chiesara, Adriano Flora, Diego Fornasari, Michela Ferraris, Laura Marabini, Helen Lucchetti, Sonia Radice |
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| Rok vydání: | 2005 |
| Předmět: |
Transcriptional Activation
Health Toxicology and Mutagenesis Cytochrome P4501s Aryl hydrocarbon receptor Rainbow trout hepatocytes Reporter gene assay Luciferase Iprodione 3-Metylcholanthrene Aquatic Science Genes Reporter Toxicity Tests Transcriptional regulation medicine Animals Humans Staurosporine Luciferases Promoter Regions Genetic Cells Cultured Analysis of Variance Reporter gene biology Hydantoins Transfection Aminoimidazole Carboxamide Blotting Northern biology.organism_classification Genistein Molecular biology Fungicides Industrial Trout Gene Expression Regulation Receptors Aryl Hydrocarbon Oncorhynchus mykiss Settore BIO/14 - Farmacologia Hepatocytes biology.protein Rainbow trout Aryl Hydrocarbon Hydroxylases medicine.drug |
| Zdroj: | Aquatic Toxicology. 72:209-220 |
| ISSN: | 0166-445X |
| Popis: | The dicarboximide fungicide iprodione (Ip) causes oxidative damage as a result of the production of free oxygen radicals, and induces cytochrome P4501A3 (CYP1A3) in cultured rainbow trout hepatocytes. The aim of this study was to characterise some of the molecular mechanisms by means of which Ip activates the aryl hydrocarbon receptor (AhR) and subsequently induces the CYP1A3 gene in rainbow trout (Oncorhynchus mykiss). The study was performed using primary hepatocytes and transfected HepG2 cells with a reporter construct, in which luciferase gene expression is under the transcriptional control of a multimerised xenobiotic response elements (4XREs), or a 2.3 Kb DNA fragment (corresponding to the trout CYP1A3 gene promoter). Ip exposure increased rainbow trout hepatocyte CYP1A3 mRNA over time and increased the expression of reporter gene in HepG2, thus suggesting that Ip induces the CYP1A3 gene by activating the AhR. Genistein, a tyrosine kinase inhibitor, efficiently inhibited the Ip-mediated induction of the CYP1A3 gene as demonstrated by mRNA level decrease and the impaired activation of the luciferase reporter gene constructs. Staurosporine, an inhibitor of protein kinase C, also suppressed the induction by Ip. When the AhR antagonist α-naphthoflavone was added to the cultures, Ip-mediated CYP1A3 induction was suppressed. These findings are consistent with a mechanism of Ip-mediated CYP1A3 gene induction that involves the activation of the AhR complex via phosphorylation–dephosphorylation reactions. |
| Databáze: | OpenAIRE |
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