Development of an in vitro renal epithelial disease state model for xenobiotic toxicity testing. Issue 1 (25th December 2015)

• Record Type: Journal Article
• Authors: Crean, Daniel; Bellwon, Patricia; Aschauer, Lydia; Limonciel, Alice; Moenks, Konrad; Hewitt, Philip; Schmidt, Tobias; Herrgen, Karin; Dekant, Wolfgang; Lukas, Arno; Bois, Frederic; Wilmes, Anja; Jennings, Paul; Leonard, Martin O.
• Is Part Of: Toxicology in vitro. Volume 30:Issue 1 Part A (2015)
• Page Start: 128
• Page End: 137
• Publication Date: 2015-12-25
• Subjects: Nephrotoxicity -- Chronic kidney disease -- Proximal tubule -- Hypoxia; Toxicity testing -- In vitro -- Periodicals; Toxicology -- Periodicals; 615.9
• DOI: 10.1016/j.tiv.2014.11.015
• Languages: English
• ISSNs: 0887-2333

Abstract

Highlights: Adefovir toxicity in proximal tubular cells is enhanced under hypoxic stress. Adefovir accumulation in hypoxia is paralleled by reduction in efflux regulators including MRP4 and NHERF3. HIF activator DMOG also causes a reduction in efflux regulators. Gene expression profiling reveals novel insight into the mechanisms of ntRTI toxicity. Abstract: There is a growing impetus to develop more accurate, predictive and relevant in vitro models of renal xenobiotic exposure. As part of the EU-FP7, Predict-IV project, a major aim was to develop models that recapitulate not only normal tissue physiology but also aspects of disease conditions that exist as predisposing risk factors for xenobiotic toxicity. Hypoxia, as a common micro-environmental alteration associated with pathophysiology in renal disease, was investigated for its effect on the toxicity profile of a panel of 14 nephrotoxins, using the human proximal tubular epithelial RPTECT/TERT1 cell line. Changes in ATP, glutathione and resazurin reduction, after 14 days of daily repeat exposure, revealed a number of compounds, including adefovir dipivoxil with enhanced toxicity in hypoxia. We observed intracellular accumulation of adefovir in hypoxia and suggest decreases in the efflux transport proteins MRP4, MRP5, NHERF1 and NHERF3 as a possible explanation. MRP5 and NHERF3 were also down-regulated upon treatment with the HIF-1 activator, dimethyloxalylglycine. Interestingly, adefovir dependent gene expression shifted from alterations in cell cycle gene expression to an inflammatory response in hypoxia. The ability to investigate aspects of disease states and their influence on renal toxin handling is a key advantage of in vitro systems developed here. They also allow for detailed investigations into mechanisms of compound toxicity of potential importance for compromised tissue exposure.