EHESP, Inserm, Irset (Institut de recherche en sante, environnement et travail)-UMR_S 1085, Univ. Rennes, 35000, Rennes, France.
Department of Physiological Sciences, University of Florida, 1333 Center Drive, Box 100144, Gainesville, FL, 32610, USA.
Epigenetics Chromatin. 2024 May 7;17(1):14. doi: 10.1186/s13072-024-00539-5.
Prenatal nicotine exposure (PNE) has been documented to cause numerous deleterious effects on fetal development. However, the epigenetic changes promoted by nicotine exposure on germ cells are still not well understood.
In this study, we focused on elucidating the impact of prenatal nicotine exposure on regulatory epigenetic mechanisms important for germ cell development.
Sprague-Dawley rats were exposed to nicotine during pregnancy and male progeny was analyzed at 11 weeks of age. Testis morphology was analyzed using frozen testis sections and expression of germ cell markers was examined by RT-qPCR; histone modifications were assessed by Western Blot (WB). DNA methylation analysis was performed by methylation-specific PCR of bisulfite converted DNA. Genome-wide DNA methylation was analyzed using Methylated DNA immunoprecipitation (MeDIP)-seq. We also carried out transcriptomics analysis of pituitary glands by RNA-seq.
We show that gestational exposure to nicotine reduces germ cell numbers, perturbs meiosis, affects the expression of germ line reprogramming responsive genes, and impacts the DNA methylation of nervous system genes in the testis. PNE also causes perturbation of gene expression in the pituitary gland of the brain.
Our data demonstrate that PNE leads to perturbation of male spermatogenesis, and the observed effects are associated with changes of peripheral nervous system signaling pathways. Alterations in the expression of genes associated with diverse biological activities such as cell migration, cell adhesion and GABA signaling in the pituitary gland underscore the complexity of the effects of nicotine exposure during pregnancy.
已有研究证明，产前尼古丁暴露（PNE）会对胎儿发育造成诸多有害影响。然而，尼古丁暴露对生殖细胞的表观遗传变化仍知之甚少。
本研究旨在阐明产前尼古丁暴露对生殖细胞发育中重要的调控表观遗传机制的影响。
将怀孕的斯普拉格-道利大鼠暴露于尼古丁中，并在 11 周龄时分析雄性后代。通过冷冻睾丸切片分析睾丸形态，通过 RT-qPCR 检测生殖细胞标记物的表达；通过 Western Blot（WB）评估组蛋白修饰。通过亚硫酸氢盐转化 DNA 的甲基化特异性 PCR 进行 DNA 甲基化分析。通过甲基化 DNA 免疫沉淀（MeDIP）-seq 分析全基因组 DNA 甲基化。我们还通过 RNA-seq 对垂体进行了转录组学分析。
我们发现，妊娠期暴露于尼古丁会减少生殖细胞数量，扰乱减数分裂，影响生殖细胞重编程反应基因的表达，并影响睾丸中神经系统基因的 DNA 甲基化。PNE 还会导致脑垂体中基因表达的紊乱。
我们的数据表明，PNE 导致男性精子发生障碍，并且观察到的影响与外周神经系统信号通路的改变有关。垂体中与多种生物活性相关的基因（如细胞迁移、细胞黏附和 GABA 信号）表达的改变突出了怀孕期间尼古丁暴露的复杂性。
