Human Pesticide Exposure and Epigenetic Changes in Sperm DNA

 描述（由申请人提供）：人类暴露于多种农药。许多研究记录了农药暴露对精子质量的有害影响，这些研究都是在实验室和动物模型上推断的，而人类直接接触农药的研究结果有限。许多人类研究都集中在持久性杀虫剂的使用上，比如DDT（二氯二苯三氯乙烷），谢天谢地，在发达国家，DDT的使用正在减少。然而，越来越多的研究表明，当代非持久性农药对人类精液参数的有害影响，包括精子浓度和活力降低。拉丁美洲移民农场工人，其中大多数是男性，是一个健康不同的人口直接和频繁接触农药。这些人提供了一个机会，以检查接触当代，非持久性农药对人类精子质量的机制和影响。生殖研究的一个有前途的新领域是精子的表观遗传状态与精子质量的关系。在人类中，基于临床的研究表明，DNA甲基化水平在生育能力降低的男性精子中是异常的。我们对暴露于非持久性农药后表观遗传改变的基因的理解存在重大差距。需要记录接触当代非持久性农药与男性农场工人生殖健康之间关系的数据，以便为围绕农药使用的预防战略和公共卫生政策提供信息。本项目的目标是记录杀虫剂暴露与精子发生的表观遗传变化之间的关系。我们将比较50名男性移民拉丁裔农场工人，一组经历反复接触农药，50名移民拉丁裔生活在城市，非农业社区，没有职业接触农药。拟议项目将实现三个具体目标：1.甲基化结合蛋白沉淀将用于富集印迹DNA，下一代测序将用于高（农场工人）和低（非农场工人）农药暴露的拉丁美洲男性精子基因的全基因组注释。2.我们将非持久性农药暴露的生物标志物（有机磷农药[3，5，6-三氯吡啶醇，TCPy/毒死蜱]，拟除虫菊酯类杀虫剂[3-苯氧基苯甲酸，3 PBA]和除草剂[2，4-二氯苯氧基乙酸，2，4-D]的尿代谢物）与精子基因的甲基化状态相关联。3.将确定两组男性中临床相关精液参数（精子浓度、活力和形态）、尿农药代谢物浓度和精子基因内DNA甲基化模式之间的相关性。这项研究将结合联合收割机流行病学，男科学和表观基因组学。这项研究的独特纵向设计将使我们能够评估高暴露组和低暴露组之间的横截面差异，以及整个农业季节人群和个人的变化。

 DESCRIPTION (provided by applicant): Human populations are exposed to a variety of pesticides. Much of the research documenting the detrimental effects of pesticide exposure on sperm quality has been extrapolated on laboratory and animal models with limited results from studies of direct human pesticide exposure. Many of the human studies focus on the use of persistent pesticides, such as DDT (dichlorodiphenyltrichloroethane), whose use is thankfully decreasing in the developed world. However, increasing studies suggest deleterious effects of contemporary, non-persistent pesticides on human semen parameters, including decreased sperm concentration and motility. Latino immigrant farmworkers, most of whom are men, are a health disparate population with direct and frequent exposure to pesticides. These men provide an opportunity to examine the mechanisms and effects of exposure to contemporary, non-persistent pesticides on human sperm quality. A promising new area of reproductive research relates the epigenetic state of spermatozoa to sperm quality. In humans, clinic-based studies indicate that levels of DNA methylation are abnormal in spermatozoa of men with reduced fertility. A significant gap exists in our understanding of the genes that are epigenetically alterd following exposure to non-persistent pesticides. Data documenting the association of exposure to contemporary, non-persistent pesticides on the reproductive health of male farmworkers is needed to inform prevention strategies and public health policy surrounding the use of agricultural pesticides. The goal of this project is to document the association of pesticide exposure with epigenetic changes in spermatogenesis. We will compare 50 male immigrant Latino farmworkers, a group that experiences repeated pesticide exposure, with 50 immigrant Latinos living in urban, non-agricultural communities, without occupational exposure to pesticides. The proposed project will address three specific aims: 1. Methylation binding protein precipitation will be used to enrich imprinted DNA and Next Generation sequencing will be used for genome wide annotation of spermatozoa genes in high- (farmworkers) and low- (non-farmworker) pesticide exposed Latino men. 2. We will correlate biomarkers of non-persistent pesticide exposure (urinary metabolites of organophosphorus pesticides [3,5,6-trichloropyridinol, TCPy/chlorpyrifos], pyrethroid insecticides [3-phenoxybenzoic acid, 3PBA], and herbicides [2,4- dichlorophenoxyacetic acid, 2,4-D]) with the methylation status of spermatozoa genes. 3. Associations among clinically relevant semen parameters (sperm concentration, motility and morphology), urinary pesticide metabolite concentrations and DNA methylation patterns within spermatozoa genes in both groups of men will be determined. This research will combine epidemiology, andrology and epigenomics. The unique longitudinal design of this study will allow us to evaluate cross-sectional differences between high- and low-exposure groups, and changes within populations and individuals across an agricultural season.