You are here:
Examining Effects of an Estrogenic PFAS, 1H,1H,8H,8H-Perfluorooctane-1,8-diol (FC8-diol), Using the Fathead Minnow Ecotoxchip
Citation:
Santana Rodriguez, K., Dan Villeneuve, J. Cavallin, B. Blackwell, J. Hoang, R. Hofer, K. Jensen, M. Kahl, R. Kutsi, E. Stacy, M. Morshead, AND G. Ankley. Examining Effects of an Estrogenic PFAS, 1H,1H,8H,8H-Perfluorooctane-1,8-diol (FC8-diol), Using the Fathead Minnow Ecotoxchip. SETAC, Pittsburgh, PA, November 13 - 17, 2022. https://doi.org/10.23645/epacomptox.21429543
Impact/Purpose:
Per and polyfluorinated alkyl substances (PFAS) are a class of chemicals of high concern with respect to potential effects on human health and/or ecosystems. US EPA has conducted a variety of high throughput screening assays to identify the potency and putative mode(s) of toxic action for PFAS of varying chain length and functional groups in an effort to develop structure-based models for predicting PFAS toxicity. The current study provides second tier verification of in vivo bioactivity identified through in vitro screening and also expands the screening through the use of a gene expression profiling assay that allows for identification of additional perturbed pathways. The results both enhance confidence in the tiered testing strategy adopted for PFAS and provide an evaluation of the EcoToxChip as a technological platform for potential regulatory application in ecological risk assessment. Results of these studies support EPA’s goals under the PFAS action plan.
Description:
Per- and polyfluoroalkyl substances (PFAS) are of concern due to their persistence in the environment and potential health effects to both human and wildlife. However, for many PFAS there is very limited or no toxicity information related to the modes of action in aquatic species. In a previous in vivo study, adult male fathead minnows (Pimephales promelas) were exposed via the water for four days to an ER-active PFAS; 1H,1H,8H,8H-Perfluorooctane-1,8-diol (FC8-diol). Expression of four genes known to be affected by estrogen exposure were evaluated in liver tissue using quantitative real time polymerase chain reaction (QPCR). Results showed that 0.15-1.5 mg FC8-diol/L caused an upregulation of vtg and esr1 expression and a downregulation of igf1 and apoeb similar to that caused by 1.0 µg 17β-estradiol/L (positive control). The purpose of this follow-up study was to examine whether a broader evaluation of gene expression might reveal additional mode(s) of action for this compound. To do this samples were further evaluated using EcoToxChips, a PCR array-based approach that allows for simultaneous measurement of over 375 species-specific genes of toxicological interest. A total of 25 fathead minnow liver RNA samples (5 samples from each test concentration; 0, 0.015, 0.047, 0.15 and 0.47 mg FC8-diol/L) from the original in vivo study were evaluated using the fathead minnow EcoToxChip v. 1.0. Resulting data were analyzed with the online EcoToxXplorer tool (EcoToxXplorer.ca). Among the genes analyzed, 58 and 60 were significantly up- and down-regulated respectively by one or more FC8-diol treatments. Previous QPCR results were further confirmed, with the EcoToxChips showing an upregulation of vtg and esr1 and downregulation of igf1 (apoeb is not present on the chip). Additional genes related to estrogen receptor activation like esr2a and esrrb were also affected providing further confirmation of the estrogenic nature of FC8-diol. Furthermore, genes such as lpl, hmgcra, acsl5, acss2, acadvl, dgat2 and scd that are involved in additional biological pathways related to fatty acid degradation and lipid metabolism were significantly affected. These results both add confidence in the use of EcoToxChips as a general tool for inferring chemical mode(s) of action and provide some further insights as to possible biological effects of FC8-diol. The contents of this presentation neither constitute, nor necessarily reflect, US EPA policy.
URLs/Downloads:
DOI: Examining Effects of an Estrogenic PFAS, 1H,1H,8H,8H-Perfluorooctane-1,8-diol (FC8-diol), Using the Fathead Minnow Ecotoxchip
SETAC 2022 FC8 DIOL ECOTOXCHIP POSTER - KELVIN J SANTANA RODRIGUEZ - FINAL.PDF (PDF, NA pp, 1211.401 KB, about PDF)