Burke CG, Myers JR, Post CM, Boulé LA, Lawrence BP. DNA Methylation Patterns in
CD4+ T Cells of Naïve and Influenza A Virus-Infected Mice Developmentally Exposed to an Aryl Hydrocarbon Receptor Ligand.
ENVIRONMENTAL HEALTH PERSPECTIVES 2021;
129:17007. [PMID:
33449811 PMCID:
PMC7810290 DOI:
10.1289/ehp7699]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/08/2020] [Accepted: 12/22/2020] [Indexed: 05/20/2023]
Abstract
BACKGROUND
Early life environmental exposures can have lasting effects on the function of the immune system and contribute to disease later in life. Epidemiological studies have linked early life exposure to xenobiotics that bind the aryl hydrocarbon receptor (AhR) with dysregulated immune responses later in life. Among the immune cells influenced by developmental activation of the AhR are CD 4 + T cells. Yet, the underlying affected cellular pathways via which activating the AhR early in life causes the responses of CD 4 + T cells to remain affected into adulthood remain unclear.
OBJECTIVE
Our goal was to identify cellular mechanisms that drive impaired CD 4 + T-cell responses later in life following maternal exposure to an exogenous AhR ligand.
METHODS
C57BL/6 mice were vertically exposed to the prototype AhR ligand, 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD), throughout gestation and early postnatal life. The transcriptome and DNA methylation patterns were evaluated in CD 4 + T cells isolated from naïve and influenza A virus (IAV)-infected adult mice that were developmentally exposed to TCDD or vehicle control. We then assessed the influence of DNA methylation-altering drug therapies on the response of CD 4 + T cells from developmentally exposed mice to infection.
RESULTS
Gene and protein expression showed that developmental AhR activation reduced CD 4 + T-cell expansion and effector functions during IAV infection later in life. Furthermore, whole-genome bisulfite sequencing analyses revealed that developmental AhR activation durably programed DNA methylation patterns across the CD 4 + T-cell genome. Treatment of developmentally exposed offspring with DNA methylation-altering drugs alleviated some, but not all, of the impaired CD 4 + T-cell responses.
DISCUSSION
Taken together, these results indicate that skewed DNA methylation is one of the mechanisms by which early life exposures can durably change the function of T cells in mice. Furthermore, treatment with DNA methylation-altering drugs after the exposure restored some aspects of CD 4 + T-cell functional responsiveness. https://doi.org/10.1289/EHP7699.
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