Project 5: Project Summary/Abstract PAHs and NDMA are common environmental pollutants that are known to be carcinogenic and are found in high quantities at superfund sites, including the Mystic River Watershed and the former Loring Air Force Base in Maine. Potential adverse health effects of these compounds are concerning to the people in these communities, as NDMA has been detected in well water in Wilmington MA, and the Maine Department of Human Services established a fish advisory stating that weekly consumption of fish from water contaminated by the Loring Air Force Base will lead to an increased risk of cancer. Unfortunately, beyond genotoxicity, the mechanisms underlying potential adverse health effects associated with either acute exposure or chronic, low-dose exposures to these compounds are poorly characterized; yet it is known that PAHs, for instance, have widespread effects on a variety of different cell types and tissues. To determine the systemic, molecular network and cellular effects of exposure to these compounds in this Project we will utilize a systems toxicology approach comprising cutting-edge mass spectrometry for protein phosphorylation profiling, next-gen sequencing for transcript expression profiling, and computational modeling to integrate molecular network data with cell phenotypic data. In collaboration with Projects 3 and 4, we will assess the effects of acute and chronic exposure on the lungs and liver of infant and juvenile mice, connecting molecular network effects with DNA mutation signatures and downstream biological effects while assessing genetic susceptibility. As Projects 1 and 2 define the concentrations and compositions of N-Nitrosodimethylamine (NDMA) and PAHs at these Superfund sites, we will perform in vitro and in vivo studies to assess the combined effects arising from these real-world mixtures, assessing the additivity and synergy of these mixtures compared to the individual compounds. This innovative, integrative strategy will provide new information regarding the health risks and mechanisms underlying exposure to the chemical contaminants present at these sites. Moreover, integrating this information into a predictive quantitative computational model that couples exposure to network response and resulting phenotype will (a) define biomarker signatures of exposure that can be used as an initial starting point for an eventual blood test for exposure signatures, (b) define network nodes governing sensitivity to exposure and therefore potential therapeutic intervention points to abrogate adverse health responses to exposure. Together, the results of this project will not only help to define the health risks for communities at risk, but may also provide potential therapeutic strategies to minimize adverse outcomes from exposures at these sites. These deliverables will have direct relevance to SRP stakeholders, including the EPA and the Massachusetts Department of Public Health.