Dose-response analysis of epigenetic, metabolic, and apical endpoints after short-term exposure to experimental hepatotoxicants.

Abstract

Identification of sensitive and novel biomarkers or endpoints associated with toxicity and carcinogenesis is of a high priority. There is increasing interest in the incorporation of epigenetic and metabolic biomarkers to complement apical data; however, a number of questions, including the tissue specificity, dose-response patterns, early detection of those endpoints, and the added value need to be addressed. In this study, we investigated the dose-response relationship between apical, epigenetic, and metabolomics endpoints following short-term exposure to experimental hepatotoxicants, clofibrate (CF) and phenobarbital (PB). Male F344 rats were exposed to PB (0, 5, 25, and 100 mg/kg/day) or CF (0, 10, 50, and 250 mg/kg/day) for seven days. Exposure to PB or CF resulted in dose-dependent increases in relative liver weights, hepatocellular hypertrophy and proliferation, and increases in Cyp2b1 and Cyp4a1 transcripts. These changes were associated with altered histone modifications within the regulatory units of cytochrome genes, LINE-1 DNA hypomethylation, and altered microRNA profiles. Metabolomics data indicated alterations in the metabolism of bile acids. This study provides the first comprehensive analysis of the apical, epigenetic and metabolic alterations, and suggests that the latter two occur within or near the dose response curve of apical endpoint alterations following exposure to experimental hepatotoxicants.

• Authors: Isabelle R Miousse, Lynea A Murphy, Haixia Lin, Melissa R Schisler, Jinchun Sun, Marie-Cecile G Chalbot, Radhakrishna Sura, Kamin Johnson, Matthew J LeBaron, Ilias G Kavouras, Laura K Schnackenberg, Richard D Beger, Reza J Rasoulpour, Igor Koturbash
• Journal: Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association (Food Chem Toxicol) Vol. 109 Issue Pt 1 Pg. 690-702 (Nov 2017) ISSN: 1873-6351 [Electronic] England
• PMID: 28495587 (Publication Type: Journal Article)
• Copyright: Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical References

• Cytochrome P-450 Enzyme System
• Clofibrate
• Phenobarbital

Topics

• Animals
• Clofibrate (analysis, toxicity)
• Cytochrome P-450 Enzyme System (genetics, metabolism)
• DNA Methylation (drug effects)
• Dose-Response Relationship, Drug
• Epigenomics
• Gene Expression (drug effects)
• Liver (drug effects, enzymology)
• Male
• Phenobarbital (analysis, toxicity)
• Rats
• Rats, Inbred F344