Imprinted Gene Regulation by in utero Lead Exposure in Mice

About This Grant

PROJECT SUMMARY The objective of this study is to determine epigenetic mechanisms that impact genomic imprinting upon in utero exposure of mice to human-relevant levels of lead (Pb). Pb is an infamous environmental exposure to human populations in the US and around the world, due in part to its neurotoxic effects. Pb exposure during early development has been linked to adverse health outcomes later in life. Preliminary data generated for this grant indicates that in utero and perinatal Pb exposure increases placenta/embryo size, and alters the DNA methylation of imprinted genes, respectively. However, the molecular mechanisms by which Pb exposure reprograms genomic imprinting during early gestation remain largely unknown. Imprinted genes are epigenetically regulated in a parent-of-origin specific manner with their mono-allelic expression driving critical periods of development. Known mechanisms of genomic imprinting include the 1) long non-coding RNA (lncRNA) and 2) insulator models, each of which program allele-specific regulation of imprinting control regions. Although dysfunctional genomic imprinting is implicated in several human diseases, the mechanisms leading to toxicant-induced imprinting dysregulation by the two models remain poorly understood. Using an established Pb exposure mouse model, this study seeks to determine in utero mechanisms that impact genomic imprinting and health effects from altered epigenetic reprogramming. Thus, female animals exposed to Pb two weeks prior to mating through 13-14 days post-conception will be used in the following Aims: 1) Determine fetal sex-specific imprinting dysregulation associated with in utero Pb exposure in mouse placenta, 2) Assess allele- and sex-specific mechanisms of in utero Pb exposure regulating genomic imprinting in the brain. Pb-exposed animals will be compared against controls to investigate genomic imprinting mechanisms in the lncRNA and insulator models by characterizing sex-, tissue-, and developmental stage-specific imprinted gene dysregulation via phenotypic, gene expression, DNA methylation, and immunohistochemical analyses. This study will reveal Pb-associated lncRNA mechanisms that inform the current epigenetic reprogramming by fetal sex. The University of Michigan provides an ideal environment to conduct the proposed research in collaboration with multiple core facilities outlined herein. The candidate will receive mentorship from a multidisciplinary team of experts to: 1) Gain proficiency in computational and statistical skills required for data analysis; 2) Acquire expertise in developmental toxicological research and mechanistic investigation; and 3) Build skills critical for leadership, teaching and mentoring, laboratory management, and grantsmanship. The proposed study will address fundamental knowledge gaps of genomic imprinting in the field to inform potential Pb-induced disease interventions. The training and research goals established in this K01 proposal constitute an exceptional foundation to ensure the candidate success in obtaining research independence.