Epigenetics Landscape in the Testes of Fertile and Infertile Men

摘要：试点项目 在人类中，10-20%的不育男性是无精子症，这意味着他们缺乏精子。在这两种类型中， 在许多情况下，非阻塞性（无堵塞）无精子症是特发性的。成熟精子的产生包括 复杂的发育过程，最终产生用于受孕的专门细胞。在这些 过程包括表观遗传编程。而产前生殖器基因组规模的DNA 虽然甲基化编程已经得到了很好的研究，但出生后睾丸细胞的表观遗传景观还没有。 目前的证据表明，异常的表观遗传修饰可能是导致 特发性非梗阻性无精子症然而，这可能与细胞组成有关，而不是病因。 生精障碍为了区分这些可能性，需要进行研究，以确定是否 在非梗阻性无精子症中，特定精原细胞和Sertoli细胞的表观遗传景观发生改变。 在目的1中，我们假设出生后精原细胞的异常表观遗传景观在以下方面发挥作用： 无精子症是由于病因而不是整个睾丸细胞组成。为了验证这个假设，我们将使用两个 无精子症遗传小鼠模型来描述DNA甲基化和染色质可及性是否 暴露了第一个模型将使用条件性的方法消除所有从头甲基转移酶活性。 Dnmt 3a/Dnmt 3b双突变体靶向生殖细胞区室，而第二个模型将采用 雄激素受体敲除（SCARKOtm2.1）靶向Sertoli室。在目标2中，我们假设， 非梗阻性无精子症的男性， 生殖细胞或支持细胞。为了验证这些假设，我们将产生DNA甲基化， 来自正常未分化和分化的染色质可及性和表达参考序列 精原细胞以及支持细胞，然后我们将比较这些细胞的概况， 突变小鼠或具有成熟停滞或仅支持细胞综合征的男性。为了这两个目的，细胞将被分离， 使用相同的富集策略，DNA甲基化，染色质可及性和表达景观 对于未分化的精原细胞，将使用 NMT-seq（核小体，甲基化和转录测序），允许比较分析 老鼠和人类。总体而言，我们将产生有关生殖细胞表观遗传景观的基础数据 和睾丸的体细胞，并确定这一景观是否在不育小鼠和男性中改变。

Abstract: Pilot Project In humans, 10-20% of infertile men are azoospermic, meaning that they lack spermatozoa. Of the two types, non-obstructive (no blockage) azoospermia, in many cases, is idiopathic. Production of mature sperm involves complex developmental processes, ultimately generating specialized cells for conception. Amongst these processes includes epigenetic programming. While prenatal prospermatogonial genome-scale DNA methylation programming has been well studied, the epigenetic landscape of postnatal testicular cells has not. Current evidence suggests that aberrant epigenetic modifications may be one mechanism that leads to idiopathic, non-obstructive azoospermia. However, this may relate to cell composition rather than etiologies of spermatogenic failure. To distinguish between these possibilities, studies are required to determine whether the epigenetic landscape of specific spermatogonial and Sertoli cells is altered in non-obstructive azoospermia. In Aim 1, we hypothesize that aberrant epigenetic landscapes in postnatal spermatogonia play a role in azoospermia due to etiology rather than whole testes cell composition. To test this hypothesis, we will use two genetic mouse models with azoospermia to delineate whether DNA methylation and chromatin accessibility are compromised. The first model will eliminate all de novo methyltransferase activity using conditional Dnmt3a/Dnmt3b double mutants targeting the germ cell compartment, while the second model will employ the androgen receptor knockout (SCARKOtm2.1) targeting the Sertoli compartment. In Aim 2, we hypothesis that men with non-obstructive azoospermia will harbor aberrant DNA methylation and chromatin accessibility within either the germ cell or Sertoli compartments. To test these hypothesis, we will produce DNA methylation, chromatin accessibility and expression reference sequences from normal undifferentiated and differentiating spermatogonia as well as Sertoli cells, following which we will compare the profile of these cells to those from mutant mice, or men with maturation arrest or Sertoli cell only syndrome. For both aims, cells will be isolated using the same enrichment strategy, and DNA methylation, chromatin accessibility and expression landscapes for undifferentiated spermatogonia, differentiating spermatogonia and Sertoli cells will be generated using NMT-seq (nucleosome, methylation and transcription sequencing), allowing comparative analysis between mouse and human. Overall, we will produce foundational data about the epigenetic landscape in germ cells and somatic cells of the testes and determine whether this landscape is altered in infertile mice and men.