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Application of the Attagene FACTORIAL™ assay to characterization of surface waters from a nationwide assessment of streams
Citation:
Blackwell, B., G. Ankley, P. Bradley, S. Li, K. Houck, AND Dan Villeneuve. Application of the Attagene FACTORIAL™ assay to characterization of surface waters from a nationwide assessment of streams. SETAC North America, Orlando, FL, November 06 - 10, 2016.
Impact/Purpose:
not applicable
Description:
Bioassays can be used to evaluate the integrated effects of complex mixtures from both known and unidentified contaminants present in environmental samples. However, such bio-monitoring approaches have typically focused only on one or a few pathways (e.g. estrogen receptor, androgen receptor) despite the fact that the chemicals in a mixture may exhibit a range of biological activities. High-throughput screening approaches that can rapidly assess samples for a broad diversity of biological activities offer a means to provide a more comprehensive characterization of complex mixtures. The Attagene FactorialTM platform is a high-throughput, cell based assay utilized by US EPA’s ToxCast Program, which provides high-content assessment of over 90 different gene regulatory pathways and all 48 human nuclear receptors (NRs). This assay has previously been used in a preliminary screening of surface water extracts from sites across the Great Lakes. In the current study, surface waters samples from 38 sites were collected, extracted, and screened through the Factorial assay as part of a USGS nationwide stream assessment. All samples were evaluated in a six point, 3-fold dilution series and analyzed using the ToxCast Data Pipeline (TCPL) to generate dose-response curves and corresponding half-maximal activity concentration (AC50) estimates. A total of 27 assay endpoints responded to extracts from one or more sites, with up to 14 assays active for a single extract. The four sites in four different states with the greatest number of active endpoints, ranging from 10 to 14, all were associated with anthropogenic wastewater inputs. Across assay endpoints, pregnane X response element (PXRE), aryl hydrocarbon (Ahr), and estrogen response element (ERE) were the most commonly activated endpoints, at 38, 33, and 25 sites, respectively. The results highlight the applicability of cell based, high-throughput assays, specifically the Attagene Factorial assay, to screening level prioritization of environmental sites or of biological pathways that may be adversely impacted.