Biomarkers of Exposure in Human Proximal Tubular Cells Incubated with Nephrotoxic Environmental Chemicals and Drugs: Altered Metabolic Pathways

Abstract ID 90586 Poster Board 211 Metabolic pathways that differed in primary cultures of human proximal tubular (hPT) cells exposed to low concentrations of nephrotoxic environmental chemicals and drugs were identified by analysis of extracellular medium using high resolution mass spectrometry coupled with ultrahigh performance liquid chromatography. hPT cells were incubated for three time points with one of three concentrations of an environmental contaminant [S-(1,2-dichlorovinyl)-L-cysteine (DCVC) or HgCl₂] or a clinically used drug whose efficacy is dose-limited by nephrotoxicity [cisplatin (CDDP), polymyxin B (PmxB), or tenofovir disoproxil fumarate (TDF)]. Cytotoxicity was also assessed by abundance of Kidney Injury Molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in the culture media from exposed hPT cells. For most of the exposure times and concentrations, little or only modest effects were observed in enzyme release, suggesting minimal cytotoxicity. With exposures to DCVC and HgCl₂, several common pathways were identified as being altered by analysis of metabolites, including fatty acid metabolism, pyrimidine metabolism, and several pathways of amino acid metabolism. For the three nephrotoxic drugs, fatty acid metabolism and several amino acid metabolism pathways were altered. Additionally, prostaglandin formation from arachidonate was a prominent and common pathway altered. These findings support the overall hypothesis that altered secretion of metabolites representing specific metabolic pathways can be identified in the absence of significant cytotoxicity and that they may serve as candidate biomarkers of early exposure to diverse nephrotoxicants. Funded by NIEHS Grant 1R01ES031584.