The following proposals were approved for funding in 2006:
Project 1: Effects of Diesel Exhaust Particles on Influenza-induced Nasal Inflammation in Allergic Rhinitics
PI:Terry L. Noah, MD; Associate Professor and Division Chief, UNC Pediatric Pulmonology
Project 2: Metals and Biomarkers of Joint Metabolism in a Community-based Cohort: The Johnston County Osteoarthritis Project
PI: Joanne M. Jordan, MD MPH; Associate Professor, Medicine and Orthopaedics, and Adjunct Associate Professor, Epidemiology
Project: Effects of Diesel Exhaust Particles on Influenza-induced Nasal Inflammation in Allergic Rhinitics
Principal Investigator: Terry L. Noah, MD; Associate Professor and Division Chief, UNC Pediatric Pulmonology
Asthma is exacerbated commonly by viruses and pollutants, but little is currently known about the effects of interaction of these factors on allergic or asthmatic inflammation. Our preliminary data suggest that exposure of human respiratory epithelium to DEP causes increased infectivity for influenza virus and increased expression of inflammatory factors in vitro and in mice in vivo. We propose a clinical/translational study testing the hypothesis that allergic rhinitics (AR) have enhanced inflammatory responses to live attenuated influenza virus (LAIV) following diesel DEP exposures, through a randomized, prospective comparison study between cohorts of AR subjects receiving DEP/placebo, followed by LAIV. Primary outcomes will be production of IL-13 and ECP, two markers of allergic inflammation, at the mucosal surface. A large number of secondary outcomes will be assessed including inflammatory cells, other cytokines and mediators, expression profiles for Phase II network genes in biopsied nasal epithelium, and the effect of genotype for the antioxidant gene GTSM1. The relevance of this work to public health is the possibility of identifying novel antioxidant strategies for reducing the impact of inhaled oxidant pollutants on virus-induced asthma exacerbations. This project would generate preliminary data for an NIH application extending our initial findings and testing potential therapeutic interventions.
Project: Metals and Biomarkers of Joint Metabolism in a Community-based Cohort: The Johnston County Osteoarthritis Project
Principal Investigator: Joanne M. Jordan, MD MPH; Associate Professor, Medicine and Orthopaedics, and Adjunct Associate Professor, Epidemiology
Accumulating toxicological data suggest that exposure to metals results in skeletal and joint toxicity. Yet, little attention has been directed to metals in relationship to osteoarthritis (OA), the most common cause of arthritis, characterized by profound bone and cartilage disruption. The primary objective is to understand how toxic metals (lead [Pb] and mercury [Hg]) affect OA. This proposal leverages bio-specimens and data from The Johnston County Osteoarthritis Project, a population-based prospective cohort of OA in African-American and White adults, in which associations between Pb, Hg, and selenium (Se) and OA were seen. Using linear regression and analysis of covariance, we will investigate associations between whole blood Pb and toenail Hg and 5 biomarkers of joint tissue metabolism related to OA pathophysiology in 376 men. Together with extant data on 375 women, we will examine factors likely to interfere with mechanisms of metal-associated OA (age, sex, and race) and identify factors (e.g., Se) that may counteract adverse responses to metal exposures. Further, this proposal will provide preliminary data for planned NIH proposals to examine additional metals in OA.
Project 1: Susceptibility to Prenatal Dieldrin Exposure in a Model for Anxiety/Aggression Disorders
PI: Jean M. Lauder, PhD, professor, Department of Cell and Developmental Biology
Project 2: Environmental Agents and Early Onset of Aging and Age-Related Diseases
PI: Paul Chastain II, PhD, postdoctoral research associate, Department of Pathology and Laboratory Medicine
Project 3: Purines in Exhaled Breath Condensate as Biomarkers of Inflammation
PI: Charles R. Esther Jr., MD, PhD, assistant professor, Division of Pediatric Pulmonology, Department of Pediatrics
Project 4: Dietary a-tocopherol Supplementation as a Way to Decrease Neuroinflammation Following Exposure to Environmental Agents
PI: Patricia A. Sheridan, PhD, postdoctoral fellow, Department of Nutrition
Project 5: Effects of Cadmium on DNA Synthesis, Cell Cycle Control and Microsatellite Mutation Rate in Human Cells in Culture
PI: Jayne C. Boyer, PhD, assistant professor, Department of Pathology and Laboratory Medicine
Project 6: Comparison of Two Measures of Oxidative DNA Damage, the Comet Assay and 7-hydroxy-8-oxo-2-deoxyguanosine, in Healthy African American and White Adults
PI: Jessie Satia, PhD, MPH, Assistant Professor of Epidemiology and Nutrition
Project: Susceptibility to Prenatal Dieldrin Exposure in a Model for Anxiety/Aggression Disorder
Principal Investigator: Jean M. Lauder, PhD; Professor of Cell & Developmental Biology
Previous studies have shown that prenatal dieldrin exposure alters development of both the GABAergic and serotonergic (5-HT) systems [reviewed by (Lauder and Liu, 1998)]. Consequently, such prenatal exposure may enhance a diathesis for psychopathology characterized by deficient GABAergic and serotonergic neurotransmission (e.g., affective disorders like anxiety and aggression). This hypothesis will be tested using a mouse model for anxiety/aggression to determine the effects of prenatal dieldrin exposure on behavior and brain neurochemistry. Relative to ICR mice selectively bred for low aggression (NC100), high aggression mice (NC900) reproduce traits associated with human anxiety disorders. Importantly, the higher levels of anxiety and aggression observed in the NC900 mice are negatively correlated with markers of GABAergic and serotonergic function (Nehrenberg, 2004; Nehrenberg et al., 2005). Behaviorally, unselected ICR animals show intermediate (i.e., “normal”) levels of anxiety and aggression relative to NC900 and NC100 mice. This animal model represents a unique tool for determining whether individuals at risk for developing affective disorders may be more susceptible to the persistent effects of dieldrin exposure during prenatal development.
Project: Environmental Agents and Early Onset of Aging and Age-Related Diseases
Principal Investigator: Paul Chastain II, PhD, postdoctoral research associate, Department of Pathology and Laboratory Medicine
Cells are continuously exposed to environmental agents that directly or indirectly create reactive oxygen species (ROS). When the cell’s capacity to eliminate ROS is overwhelmed, oxidative stress occurs and results in widespread oxidation of proteins and DNA. This macromolecular oxidation process has been implicated in the developments of cancer, degenerative diseases, and aging. However, the mechanism by which ROS promote the onset of disease and aging has not been identified. Recently, we found that a large proportion of oxidative damage in the form of abasic (AP) sites occurs non-randomly in cellular DNA. In this pilot project we propose to determine the location of non-random AP sites in low-passage and high-passage/near senescence cells using microarray technology and bioinformatics; establish whether environmentally-induced oxidative stress increases the number of non-random sites; and search for common and/or unique sequence features among genomic regions that contain non-random sites. These findings may allow us to correlate exposure of young cells to environmental agent promoting oxidative damage to premature aging and disease, and exposure of old cells to the same agents to accelerated induction of disease.
Project: Purines in Exhaled Breath Condensate as Biomarkers of Inflammation
Principal Investigator: Charles R. Esther Jr., MD, PhD, assistant professor, Division of Pediatric Pulmonology, Department of Pediatric
Inhaled environmental insults trigger an inflammatory response in the airway and are involved in the pathogenesis of lung disease such as asthma. Extracellular purines, which act as regulatory molecules in the airway, can serve as biomarkers of this inflammation. The goal of this proposal is to develop a non-invasive method to measure airway purines as a biomarker of inflammation. Exhaled breath condensate (EBC) collection provides the non-invasive means to obtain airway samples, but EBC contains very small amounts of airway fluid. We will therefore develop sensitive methods to identify and quantify purines in EBC using the mass spectrometers in the Biomarkers Facility Core. Methods will be validated by comparing the results from EBC to the more established (though more invasive) technique of bronchoalveolar lavage, and by measuring EBC purines from subjects with the inflammatory lung disease cystic fibrosis. Once methods have been optimized and validated, we will analyze samples collected from asthmatics exposed to ozone to demonstrate that measurement of purines in EBC can be used to investigate the physiological response to environmental insults.
Project: Dietary a-tocopherol Supplementation as a Way to Decrease Neuroinflammation Following Exposure to Environmental Agents
Principal Investigator: Patricia A. Sheridan, PhD, postdoctoral fellow, Department of Nutrition
Herpes simplex virus encephalitis (HSE) is the most common fatal sporadic encephalitis in humans. Treatment with anti-viral medication such as acyclovir, decreases HSE associated mortality from 70% to 20%, however, only 38% of HSE patients recover to normal function. HSE, primarily caused by herpes simplex virus (HSV)-1 infection of the brain, results in increased levels of oxidative stress including production of reactive oxygen species, free radicals and nitric oxide and significant neuroinflammation. The most biologically active and most abundant form of vitamin E (VE) is a-tocopherol. In cellular membranes, VE prevents lipid peroxidation by scavenging free radicals and functions as an anti-oxidant. Supplementation with VE has been shown to decrease immunosenescence, improve immune function and may be neuroprotective. In this proposal we will test the hypothesis that dietary VE supplementation: 1) will decrease symptoms of HSE, viral load and spread, and decrease the production of pro-inflammatory cytokines in the brain of experimentally infected mice and 2) decrease HSE symptoms and inflammation by decreasing oxidative stress, lipid peroxidation and cyclooxygenase (COX)-2 levels and subsequent prostaglandin (PG) E2 production.
Project: Effects of Cadmium on DNA Synthesis, Cell Cycle Control and Microsatellite Mutation Rate in Human Cells in Culture
Principal Investigator: Jayne C. Boyer, PhD, assistant professor, Department of Pathology and Laboratory Medicine
Cadmium is an environmental human carcinogen that increases oxidative DNA damage and inhibits DNA repair. This study will determine the effects of cadmium on DNA replication and mismatch repair (MMR) in diploid human fibroblasts. DNA fiber immunofluorescence microscopy will be used to determine whether cadmium-induced DNA damage triggers the intra-S checkpoint to inhibit the initiation of new replicons and/or slows the rate of DNA chain elongation in active replicons. Analysis of Chk1 phosphorylation will test whether cadmium inhibits ATR signaling in response to replicative stress. For statistical significance, oxidative DNA damage will be measured and correlated with effects on DNA replication in five different lines of cadmium-treated human fibroblasts. Cadmium has been shown to increase microsatellite mutation rates in yeast and inhibit MMR in human cell extracts. Using a plasmid-based reporter system microsatellite mutation rates will be quantified in five lines of human fibroblasts after chronic exposure to cadmium. These studies will test the hypothesis that cadmium contributes to human carcinogenesis by inhibiting MMR and thereby increasing mutation rates in microsatellites as well as in non-repetitive sequences.
Project: Comparison of Two Measures of Oxidative DNA Damage, the Comet Assay and 7-hydroxy-8-oxo-2-deoxyguanosine, in Healthy African American and White Adults
Principal Investigator: Jessie Satia, PhD, MPH, Assistant Professor of Epidemiology and Nutrition
Development and optimization of intermediate biomarkers of cancer is crucial for identifying individuals at elevated risk. Oxidative DNA damage, a significant contributor to the development of many cancers, is commonly measured by direct measurements of DNA fragmentation (e.g., alkaline Comet assay) and indirect measurements based on biomarkers of DNA damage (e.g., 7-hydroxy-8-oxo-2′-deoxyguanosine (8-oxo-dG)). However, there is limited data comparing the concordance of these methods. Using data from a population-based study of associations between antioxidant nutrients and oxidative DNA damage in 165 African American and White adults in North Carolina, we are requesting funds to perform 8-oxo-dG assays as a second measure of oxidative DNA damage (along with the Comet assay) and compare the degree of agreement between these methods, as current funding only permits the Comet assays. Given the absence of solid data comparing these methods and their frequent use in research investigations, the larger sample and diverse population in this study would be useful in potentially identifying or confirming the absence of an association. Therefore, this project would represent a major methodological advance in this area of research.