Activity-Based Protein Profiling of Enzyme Ontogeny: Metabolism in Sensitive Life Stages
EMSL Project ID
47638
Abstract
Metabolism is a key step in the activation of many procarcinogens, including the polyaromatic hydrocarbon (PAH) dibenzo[def,p]chrysene (DBC). DBC is a highly potent carcinogenic PAH, capable of crossing the placental barrier and causing lymphoma in offspring of maternal mice exposed during gestation. We have developed a physiologically based pharmacokinetic (PBPK) model capable of predicting target tissue dosimetry of DBC and its carcinogenic metabolites in mice at vulnerable life stages, including pregnancy, the developing fetus, and the neonatal mouse. A key feature of this model is the description of DBC metabolism, which contributes to both the activation of the ultimately carcinogenic epoxide metabolites, as well as detoxification through metabolic clearance. While it is well known that the activity and expression of metabolizing enzymes vary through stages of development, there is a dearth of quantitative information on the ontogeny of specific enzymes. Activity-based protein profiling (ABPP) is a functional proteomics approach that facilitates the measurement of post-translational enzyme activity of over 75 enzymes relevant to PAH metabolism. In the proposed research, ABPP will be used to investigate the ontogeny of a broad spectrum of metabolizing enzymes, including cytochrome P450s, epoxide hydrolases, UDP-glucuronysl transferases, and glutathione-s-transferases, in key developmental stages in the mouse, resulting in more accurate description of target-tissue dosimetry in PBPK models of pregnancy and development. Specifically, the hepatic enzyme activity of control and DBC exposed pregnant mice, fetuses, neonates, and weanlings will be compared using ABPP, which relies on EMSL orbitrap mass spectrometric analysis. The resulting activities will be incorporated into PBPK models to investigate the differences in activity and their effects on the disposition of DBC and its metabolites. We anticipate that this foundational research will result in both peer-reviewed publication of the enzyme based PBPK model as well as future funding opportunities in the form of investigator-initiated R01s.
Project Details
Start Date
2012-09-07
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Crowell SR, A Sharma, S Amin, JJ Soelberg, NC Sadler, AT Wright, WM Baird, DE Williams, and RA Corley. 2013. "Impact of Pregnancy on the Pharmacokinetics of Dibenzo[def,p]chrysene in Mice." Toxicological Sciences 135(1):48-62. doi:10.1093/toxsci/kft124
Ismail HM, PM O'Neill, D Hong, R Finn, C Henderson, AT Wright, B Cravatt, J Hemingway, and MJ Paine. 2014. "Pyrethroid Activity-Based Probes for Profiling Cytochrome P450 Activities Associated with Insecticide Interactions." Proceedings of the National Academy of Sciences of the United States of America 110(49):19766-19771. doi:10.1073/pnas.1320185110