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OXPHOS-Dependent Cells Identify Environmental Disruptors of Mitochondrial Function
Citation:
ACKERMAN, D. A. AND S. SIMMONS. OXPHOS-Dependent Cells Identify Environmental Disruptors of Mitochondrial Function. Presented at Society of Toxicology (SOT) Annual Meeting, San Francisco, CA, March 11 - 15, 2012.
Impact/Purpose:
This presentation will detail the adaptation of an pharmaceutical assay to measure mitochodrial toxicity of environmental chemicals
Description:
Mitochondrial dysfunction is associated with numerous chronic diseases including metabolic syndrome. Environmental chemicals can impair mitochondrial function through numerous mechanisms such as membrane disruption, complex inhibition and electron transport chain uncoupling. Currently, high-throughput toxicity screening efforts by Tox21 utilize culture conditions that facilitate ATP production exclusively through glycolysis, not oxidative phosphorylation, and therefore these cells may be less susceptible to mitochondrial toxicants. To demonstrate this, we cultured HEK293T cells in media supplanted with galactose rather than glucose, thereby forcing ATP production via oxidative phosphorylation. To compare media conditions, both galactose and glucose-grown cells were exposed to fifty test compounds, including those with known mitochondrial toxicity (e.g., rotenone, antimycin and carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP)). After exposure, total cellular ATP levels were measured using the Cell Titer Glo™ viability assay. Exposure to many compounds comparably reduced viability in galactose-and glucose-grown cells. However, a subset of test compounds, including dibutyltin maleate, methyl mercury (II) chloride and thiram were much more toxic to galactose-grown cells, suggesting cytotoxicity through mitochondrial disruption. Additionally, cytotoxicity in galactose-grown cells was observed at lower concentrations than those eliciting other stress responses (Le., oxidative stress, heat shock response, etc.) in previous studies using glucose-grown cells. These results suggest that mitochondrial toxicity is a primary cause of cytotoxicity for certain environmental chemicals and cannot be properly assessed in anaerobically-conditioned cell models. (This is an abstract of a proposed presentation and does not necessarily reflect EPA policy).