DNA Methylation and Endocrine Disrupting Chemical Exposure in Children

DESCRIPTION (provided by applicant): There are abundant in vitro or animal data indicating how environmental contributions, mainly exposure to chemicals, may mediate the increasing burden of cancer, respiratory, developmental and neurological diseases through the DNA methylation mechanism. In this study, the intent is to investigate whether exposure to endocrine disrupting chemicals (EDCs) would modify DNA methylation;whether exposure-induced DNA methylation changes are reversible once the exposure is mitigated;and the interaction of multiple EDC exposures with DNA methylation in young children. This proposed study is built upon a NIEHS funded community-based intervention study in which children's exposure to pesticides will be quantitatively assessed before and after the implementation of an Integrated Pest Management program. This NIEHS study would provide a unique and time-sensitive opportunity that would allow one to collect repeated buccal cell samples from children. Using those samples, one can establish the baseline levels of DNA methylation for certain genes of diseases that are known to be associated with exposures to EDCs, such as bisphenol-A (BPA) and synthetic pyrethroids. In this study, the intent is to collect buccal cell samples using the Oragene(R) OG-500 DNA Self-Collection Kit (DNA Genotek, Ottawa) from each child in the middle of the 3-consecutive-day (the second day) urine collection in each month for 6 consecutive months. This will yield 6 buccal cell samples from each child for a total of 120 buccal cell samples. A modified bisulfite conversion analysis will be exploited followed by pyrosequencing of Alu and LINE1-repetitive elements and of promoters of the candidate genes. For all the markers pyrosequencing assays will be executed for DNA methylation analysis. Urine samples will then be analyzed for the presence of BPA. The outcomes from this R21 study will greatly enhance ones understanding of the molecular mechanism of DNA methylation changes and its interactions with EDC exposures that are so ubiquitous in children's daily environment. PUBLIC HEALTH RELEVANCE: There are abundant in vitro or animal data indicating how environmental contributions, mainly exposure to chemicals, may mediate the increasing burden of cancer, respiratory, developmental and neurological diseases through the DNA methylation mechanism. In this study, the premise is to investigate whether exposure to EDCs modifies DNA methylation in young children.