We have obtained evidence that developmental exposure to the AhR-specific ligand TCDD (dioxin) affects epigenetically-regulated events leading to long-lasting defects in the offspring's response to influenza A virus infection. Defects include reduced expansion and differentiation of virus-specific CD8+ T cells, impaired production of the antiviral cytokine IFN?. Objectives/Hypothesis: The purpose of this project is to understand how environmental signals delivered via AhR during fetal and neonatal development cause long-lasting impairment of CD8+ T cell responses to infection. Although epigenetic mechanisms are known to regulate gene expression in immune cells, the idea that inappropriate AhR activation during development causes permanent functional changes via an epigenetic mechanism is a novel paradigm. The overall hypothesis for the proposed studies is that inappropriate AhR activation during development interferes with the programming of the immune system via epigenetic mechanisms, resulting in permanent defects in gene expression that lead to long-lasting reductions in CD8+ T cell function.
Specific Aims :1) To identify the developmental and lineage-specific targets of AhR that cause long-lasting reductions in the capacity of CD8+ T cells to respond to infection, we will determine the contribution of reprogramming in specific hematopoietic lineages using a combination of progenitor cell transplantation, lineage-specific gene ablation, and adoptive transfer. 2) To identify gene targets whose expression is differentially silenced or activated by developmental exposure to dioxin, we will define AhR-mediated changes in CpG methylation and covalent histone modifications of the ifng locus, and use novel genome-wide approaches to identify additional epigenetically-regulated genes that are affected. 3) To identify epigenetic regulatory pathways modulated by AhR we will use pharmacological and genetic approaches to determine which DNA methyltransferases are affected and whether these changes contribute to impaired CD8? T cell functions, such as impaired IFN? production following infection. Significance: The proposed studies address an area that is relevant to global human health but has received inadequate attention. Influenza and other viral infections continue to pose significant global health threats. Evidence points to prenatal and early life exposure to pollutants as overlooked contributors to poorer clinical outcomes following infection. Moreover, the idea that AhR impacts epigenetic programming is innovative and has broad biological significance, as AhR plays a role in normal hematopoiesis, and developmental exposure to AhR ligands deregulates many aspects of immune function. Moreover, TCDD and other AhR ligands disrupt development of other tissues, thus findings from these studies will help us better understand how AhR ligands impact cells throughout the body, and will provide new information regarding the normal physiological role of AhR.
Recent studies reveal that prenatal and early life exposure to pollutants is an overlooked but important contributor to poorer outcomes following viral infection;however, how developmental exposures cause long- lasting defects in immune function is not clear. Using a model developmental immunotoxicant and influenza A virus as a prototypical human pathogen, the proposed research will determine how developmental exposure reprograms the offspring's immune system. This research addresses growing concern about how environmental factors contribute disease, and will improve our understanding of epigenetic regulation within the context of the developing immune system.
|Yee, Min; Domm, William; Gelein, Robert et al. (2017) Alternative Progenitor Lineages Regenerate the Adult Lung Depleted of Alveolar Epithelial Type 2 Cells. Am J Respir Cell Mol Biol 56:453-464|
|Jusko, Todd A; De Roos, Anneclaire J; Lee, Sue Y et al. (2016) A Birth Cohort Study of Maternal and Infant Serum PCB-153 and DDE Concentrations and Responses to Infant Tuberculosis Vaccination. Environ Health Perspect 124:813-21|
|Yee, Min; Gelein, Robert; Mariani, Thomas J et al. (2016) The Oxygen Environment at Birth Specifies the Population of Alveolar Epithelial Stem Cells in the Adult Lung. Stem Cells 34:1396-406|
|Boule, Lisbeth A; Burke, Catherine G; Fenton, Bruce M et al. (2015) Developmental Activation of the AHR Increases Effector CD4+ T Cells and Exacerbates Symptoms in Autoimmune Disease-Prone Gnaq+/- Mice. Toxicol Sci 148:555-66|
|Winans, Bethany; Nagari, Anusha; Chae, Minho et al. (2015) Linking the aryl hydrocarbon receptor with altered DNA methylation patterns and developmentally induced aberrant antiviral CD8+ T cell responses. J Immunol 194:4446-57|
|Grandjean, Philippe; Barouki, Robert; Bellinger, David C et al. (2015) Life-Long Implications of Developmental Exposure to Environmental Stressors: New Perspectives. Endocrinology 156:3408-15|
|Boule, Lisbeth A; Winans, Bethany; Lambert, Kris et al. (2015) Activation of the aryl hydrocarbon receptor during development enhances the pulmonary CD4+ T-cell response to viral infection. Am J Physiol Lung Cell Mol Physiol 309:L305-13|
|Reilly, Emma C; Martin, Kyle C; Jin, Guang-bi et al. (2015) Neonatal hyperoxia leads to persistent alterations in NK responses to influenza A virus infection. Am J Physiol Lung Cell Mol Physiol 308:L76-85|
|Boule, Lisbeth A; Winans, Bethany; Lawrence, B Paige (2014) Effects of developmental activation of the AhR on CD4+ T-cell responses to influenza virus infection in adult mice. Environ Health Perspect 122:1201-8|
|Yee, Min; Buczynski, Bradley W; O'Reilly, Michael A (2014) Neonatal hyperoxia stimulates the expansion of alveolar epithelial type II cells. Am J Respir Cell Mol Biol 50:757-66|
Showing the most recent 10 out of 29 publications