2,3,7,8-Tetrachlorodibenzo- p-dioxin and β-naphthoflavone induce cellular hypertrophy in H9c2 cells by an aryl hydrocarbon receptor-dependant mechanism

• Published in: Toxicology in vitro 2010-04, Vol.24 (3), p.863-871
• Main Authors: Zordoky, Beshay N.M., El-Kadi, Ayman O.S.
• Format: Article
• Language: English
• Subjects: Actins - drug effects; Actins - metabolism; AhR; Antioxidants - pharmacology; beta-Naphthoflavone - toxicity; Cell Line; Cell Size - drug effects; Cytochrome P-450 Enzyme System - genetics; Cytochrome P450s; DNA Primers; DNA, Complementary - biosynthesis; DNA, Complementary - genetics; Environmental Pollutants - toxicity; Glyceraldehyde-3-Phosphate Dehydrogenases - drug effects; Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism; H9c2 cells; Heart; Humans; Hypertrophy; Isoenzymes - chemistry; Isoenzymes - metabolism; Polychlorinated Dibenzodioxins - toxicity; Protein Folding - drug effects; Reactive Oxygen Species - metabolism; Receptors, Aryl Hydrocarbon - drug effects; Reverse Transcriptase Polymerase Chain Reaction; RNA - biosynthesis; RNA - genetics; Stilbenes - pharmacology; TCDD
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2009.12.002

Cigarette smoke is a major risk factor for cardiovascular diseases. It contains thousands of compounds that activate the aryl hydrocarbon receptor (AhR). In addition, 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD), the most potent AhR ligand, has been shown to cause cardiotoxic effects in several in vivo models. Although induction of CYP1 family is the most important effect of AhR activation, the role of CYP1 induction in mediating the cardiotoxic effect of TCDD is usually overlooked. Therefore, we investigated whether AhR activation causes a hypertrophic effect in H9c2 cells and we related this effect to changes in CYP gene expression. In the current study, the cardiac derived H9c2 cells were treated with two AhR ligands, TCDD and β-naphthoflavone (BNF), for 24 and 48 h. The expression of the hypertrophic markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), and several CYP genes were measured by real-time PCR. Treatment of H9c2 cells with TCDD or BNF for 24 h caused a significant induction of CYP1A1, CYP1B1, and CYP4A1; however, there was no change in the expression of other genes. On the other hand, treatment of the cells with TCDD or BNF for 48 h caused a significant induction of the hypertrophic markers, ANP and BNP, and several CYP genes such as CYP1A1, CYP1B1, CYP2E1, CYP2J3, and CYP4F4 parallel to a significant increase in the cell surface area. Neither TCDD nor BNF increased the oxidative stress in H9c2 cells at all concentrations tested. Interestingly, resveratrol, an AhR antagonist, protected the cells from TCDD-induced hypertrophy. In conclusion, AhR ligands caused a hypertrophic effect in H9c2 cells which was associated with induction of several CYP genes which can be prevented by resveratrol.