Mechanism Underlying the Transduction of Epimutations from the Soma to the Male Germline

项目摘要 大多数关于表观遗传的研究集中在识别携带精子的因子 表观遗传记忆以及它们如何作用于胚胎的表观基因组/基因组，从而使特定的 表观遗传记忆可以在后代身上被回忆并表现为一种特定的表型。然而，有一个 根本问题仍然没有得到回答：鉴于暴露的影响，无论是环境还是 饮食，最初可能表现为直接暴露的体细胞的表观遗传变化(例如 胰岛细胞、脂肪细胞、肝细胞等)，表型特异的表型突变是如何 体细胞被转化为精子？使用高度可重复性的小鼠模型 高脂饮食(HFD)诱导的代谢紊乱的代际表观遗传，我们在这里 提出一系列实验来解决这个关键问题。我们的中心假设是HFD- 体细胞中诱导的表观突变可以导致产生特定的SncRNAs 被包裹在细胞外小泡(EV)中，或以移动RNA的形式存在，它们充当 表观遗传记忆曾通过1)睾丸内机制被精子内化 (即，传递给所有发育中的雄性生殖细胞的支持细胞HDF特异性表观遗传信息或 在睾丸中的精子发生期间直接到达精子)，或2)睾丸后途径(即， HFD特异性表观遗传信息从男性生殖道上皮细胞传递到 精子)，或3)两者的组合。为了检验我们的假设，我们建议确定何时和 当雄性生殖细胞获得传播HDF诱导的代谢紊乱表型(Aim1)的能力时， 为了研究睾丸内途径对HFD特异性精子表观基因组(AIM2)的贡献， 研究睾丸后途径如何影响HFD特异性精子表观基因组(Aim3)。待处理的数据 这将有助于填补我们在理解潜在的分子机制方面的知识空白 父系习得性状的代际表观遗传。

Project Summary Most of the studies on epigenetic inheritance focus on the identification of sperm-borne factors that carry the epigenetic memory and how they act on the epigenome/genome of the embryos so that the specific epigenetic memory can be recalled and manifested as a specific phenotype in offspring. However, one fundamental question remains unanswered: given that the effects of exposures, either environmental or dietary, are presumably initially manifested as epigenetic changes in directly exposed somatic cells (e.g. pancreatic islet cells, adipocytes, hepatocytes, etc.), how do the phenotype-specific epimutations in somatic cells get transduced into spermatozoa? Using a highly reproducible mouse model for intergenerational epigenetic inheritance of a high fat diet (HFD)-induced metabolic disorders, we here propose a series of experiments to tackle this critical question. Our central hypothesis is that HFD- induced epimutations in somatic cells can lead to production of specific sncRNAs that are either encapsulated in extracellular vesicles (EVs), or present as mobile RNAs, which act as the carrier of epigenetic memory once internalized by spermatozoa through either 1) the intra-testicular mechanism (i.e., Sertoli cell HDF-specific epigenetic information transmitted to all developing male germ cells or directly to spermatozoa during spermatogenesis in the testis), or 2) the post-testicular pathway (i.e., HFD-specific epigenetic information transmitted from male reproductive tract epithelial cells to spermatozoa), or 3) a combination of both. To test our hypothesis, we propose to identify when and where male germ cells gain the ability to transmit the HDF-induced metabolic disorder phenotype (Aim1), to study how the intra-testicular pathway contributes to the HFD-specific sperm epigenome (Aim2), to study how the post-testicular pathway influences HFD-specific sperm epigenome (Aim3). Data to be obtained will help fill the knowledge gap in our understanding of the molecular mechanisms underlying the intergenerational epigenetic inheritance of paternally acquired traits in general.