High-Throughput Cellular Assays for Modeling Toxicity in the Fish Reproductive SystemEPA Grant Number: R835167
Title: High-Throughput Cellular Assays for Modeling Toxicity in the Fish Reproductive System
Investigators: Schultz, Irvin R.
Institution: University of Washington
EPA Project Officer: Carleton, James N
Project Period: August 1, 2012 through September 30, 2015 (Extended to September 30, 2017)
Project Amount: $1,199,908
RFA: Developing High-Throughput Assays for Predictive Modeling of Reproductive and Developmental Toxicity Modulated Through the Endocrine System or Pertinent Pathways in Humans and Species Relevant to Ecological Risk Assessment (2011) RFA Text | Recipients Lists
Research Category: Computational Toxicology , Health , Ecosystems , Safer Chemicals
Our hypotheses are that in vitro assays can provide valid estimates of specific model parameters used in computational models of fish reproduction. These models combined with toxicokinetic modeling can be used to convert in vitro estimates of contaminant effects on endocrine function to predictions on reproductive success in fish for a given environmental exposure.
We will evaluate cellular in vitro assay systems of the rainbow trout pituitary, liver and ovary for high-throughput screening (HTS) of environmental contaminants. Each assay will measure essential reproductive endocrine functions of the corresponding organ, for example FSH synthesis and secretion by pituitary cells, and permit derivation of the LOEC or AC50 for a test contaminant. Results from the in vitro assays will be used to parameterize a computational model of the trout brain-pituitary-ovary-liver (BPOL) axis to assess the impact of a contaminant on oocyte maturation and spawning. Associated with the computational modeling, is determination of the hypothetical water concentration necessary to achieve a target organ concentration comparable to the in vitro dose metrics.
The most important benefit of this project is the experimental evaluation of all essential steps in the development and testing of adverse outcome pathways (AOP) for a diverse set of reproductive and non-reproductive toxicants. In contrast to human testing and the toxicity pathway concept, testing of the ecological counterpart is much further behind. However, in vitro testing using rainbow trout cells has a long history and coupled with the superior mechanistic understanding of physiological processes controlling dosimetry, provides an excellent model system for studying implementation of the AOP process. Thus, our results will be of benefit to future studies with other ecologically important models by providing guidance on important questions such as: When considering the pituitary- gonadliver (PGL) axis, to what extent can immortalized cell lines be used and must you control for gender and maturational stage specificity? Are multi- tissue differences in toxicant sensitivity significant enough to warrant HTS of each PGL tissue or could equivalent predictions (environmental exposure scenarios) be obtained with one or two tissues used for in vitro testing?