Jonathan H. Freedman, Ph.D.
Principal Investigator and Head, WormTox Group
The NTP WormTox Facility, headed by Jonathan Freedman, Ph.D., develops toxicological assays using the nematode Caenorhabditis elegans and evaluates their utility as medium- and high-throughput screening tools.
C. elegans has been used as a biological model for decades leading to numerous discoveries in genetics, development, and neurobiology. Because C. elegans has a rapid life cycle and produces hundreds of progeny through self-fertilization, toxicological assays can be performed in a few hours to days using genetically-identical populations of animals.
Many mammalian pathways known to govern responses to chemical insults have been shown to be highly conserved in C. elegans. This suggests that chemicals that elicit a toxicological response in C. elegans are likely to affect humans.
A number of phenotypes have been observed in C. elegans after chemical exposures including changes in behavior, morphology, and gene expression; many of these phenotypes are correlated with lethality in traditional rodent models, further supporting the utility of C. elegans in predicting mammalian toxicity.
Major Areas of Research
- Development of in vivo toxicological assays to characterize the effects of toxicants on multiple phenotypes (feeding, growth, reproduction, and locomotion).
- Development of assays to monitor in vivo gene expression changes in transgenic C. elegans after exposure to various classes of environmental toxicants.
- Development of statistical methods for the analysis of C. elegans and cell-based high content screening data.
- Perform toxicity assays in support of National Toxicology Program, NIEHS Division of Intramural Research and extramural researchers.
- Screening the U.S. Environmental Protection Agency (EPA) ToxCastTM libraries
- Characterizing the potential neurotoxicity of several fluoride-containing compounds
- Characterizing the potential toxicity of flame retardants
- Characterizing the potential toxicity of ionic liquids
Jonathan H. Freedman, Ph.D., leads the WormTox Group in the Biomolecular Screening Branch of the National Toxicology Program (NTP) Division. He also leads the Comparitive Genomics Group in the Laboratory of Toxicology and Pharmacology.
Freedman received his Ph.D. in molecular pharmacology from the Albert Einstein College of Medicine in 1986. He has published 60 peer-reviewed articles in leading biomedical journals, as well as several book chapters. He served as Associate Professor of Molecular Toxicology at Duke University before joining NIEHS in 2005.