High-throughput toxicogenomic screening of chemicals in the environment using metabolically competent hepatic cell

Jill A Franzosa1, Jessica A Bonzo2, John Jack1

  • 1Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. EPA, Research Triangle Park, NC, 27711, USA.

Insights

This study used HepaRG™ cells to analyze gene expression changes in response to 1060 chemicals. The findings link chemical exposures to toxicological adverse outcome pathways through key transcription factors.

Area of Science:

  • Toxicology
  • Molecular Biology
  • Genomics

Background:

  • ToxCast provides in vitro data on chemical bioactivity but often lacks physiological relevance.
  • Existing assays frequently use cancer cell lines without integrated signaling or metabolism.
  • Differentiated HepaRG™ cells offer a physiologically relevant human liver model.

Purpose of the Study:

  • To evaluate differentiated HepaRG™ cells as a model for chemical screening.
  • To investigate chemical-induced gene expression changes and their relation to toxicological pathways.
  • To explore the molecular signaling network within HepaRG™ cell cultures.

Main Methods:

  • Quantitative polymerase chain reaction (qPCR) measured 93 gene transcripts.
  • Fluidigm 96.96 dynamic arrays were used for high-throughput gene expression analysis.
  • A Bayesian framework modeled chemical effects on six key transcription factors.

Main Results:

  • Gene expression was analyzed for 1060 chemicals across eight concentration points.
  • The model inferred chemical activity related to aryl hydrocarbon receptor, constitutive androstane receptor, pregnane X receptor, farnesoid X receptor, androgen receptor, and peroxisome proliferator-activated receptor alpha.
  • Transcriptomic data were translated into Bayesian inferences about molecular targets activating toxicological adverse outcome pathways.

Conclusions:

  • Differentiated HepaRG™ cells effectively model hepatic signaling relevant to toxicology.
  • The study provides a network model linking chemical exposures to adverse outcome pathways via transcription factor activity.
  • New insights into the HepaRG™ cell molecular signaling network were generated.