父代生殖细胞重编程关键期砷暴露跨代影响子代发育的表观遗传机制

前期实验发现父代砷暴露引起子代胚胎丢失和宫内生长受限，但机制未明。我们假设：父代生殖细胞重编程关键期砷暴露改变精子印记基因甲基化/羟甲基化模式并跨代影响子代发育。本课题以安徽优生优育队列3000对新婚夫妇为对象，评估父代砷暴露与子代宫内生长受限间关联；构建父代生殖细胞发生期和精子成熟期砷暴露动物模型，揭示父代生殖细胞重编程关键期砷暴露对子代胎盘和胎儿发育的损害作用、远期影响和跨代效应；分析父代生殖细胞重编程关键期砷暴露对精子印记基因甲基化/羟甲基化模式、子代胎盘印记基因甲基化/羟甲基化模式和胎盘特定印记基因表达的调控作用，阐明叶酸耗竭和过量活性氧在砷暴露改变精子印记基因甲基化/羟甲基化模式中的作用；采用巢式病例-对照设计，验证胎盘印记基因甲基化/羟甲基化模式和印记基因表达改变在父代砷暴露所致子代宫内生长受限中的作用。本课题为最终阐明父代砷暴露跨代影响子代发育的机制并制定预防对策提供新线索。

Preliminary experiment showed that paternal arsenic exposure induced embryo loss and fetal growth restriction, but its mechanism remained obscure. We hypothesize that paternal arsenic exposure during reprogramming critical period induces transgenerational effects on offspring development through altering methylation patterns of specific imprinted genes. The present study will measure urinary arsenic concentrations as biomarkers of paternal arsenic exposure and analyze the association between paternal arsenic exposure and fetal intra-uterine growth restriction. We will establish two mouse models of paternal arsenic exposure at stages of germ cell development and sperm maturation. We will observe arsenic-induced fetal growth restriction, long-term influence and transgenerational effects. We will analyze the effects of paternal arsenic exposure during reprogramming critical period on methylation patterns of sperm imprinted genes, methylation patterns of placental imprinted genes and expression of placental imprinted genes. We will explore the role of folic acid depletion and excess reactive oxygen species on arsenic-induced alteration of methylation patterns in sperm imprinted genes. Finally, urinary arsenic concentrations, methylation patterns of imprinted genes in human placentas and expression of specific imprinted genes in human placentas will be compared between subjects with SGA and AGA infants to verify whether alteration of methylation patterns in imprinted genes on arsenic-induced transgenerational effects on offspring development. The present study will provide the data for elucidating paternal arsenic exposure induced transgenerational effects on offspring development.