New embryological perspectives on imprinting disease

关于印记疾病的新胚胎学观点

• 批准号: MR/W024845/1
• 负责人: Anthony Perry
• 金额: $ 97.61万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FW024845%2F1
• 关键词: New; embryological; perspectives; imprinting; disease

Mammalian cells typically have two sets of chromosomes, one each inherited from the mother and the father. In most cases, both parental genes (alleles) have similar activities, but in an important minority (~0.5% of the total), the allele inherited from one parent is active relative to the corresponding allele from the other. These genes are said to be imprinted, and the balance of their expression is critical for embryonic viability and the avoidance of disease.The chromatin marks that engender imprinted gene expression can take the comparatively stable form of genomic DNA methylation and have been known for some thirty years. Recently, it has been found that histones, which package genomic DNA, also carry imprints that seem only to last during preimplantation development; after this, expression from each parental allele becomes equivalent.We recently documented both imprint types in the mouse by combining parent-discriminatory single embryo genome methylation and gene expression analyses. This work confirmed well-characterised imprints, but suggested that there exist multiple new imprinted regions that had not previously been reported, including 71 new imprinted genes called nBiX (for novel blastocyst-imprinted expressed). Mouse nBiX genes were marked by the modified histone (trimethylation of lysine 27 in histone 3, H3K27me3) and uniparentally expressed at the blastocyst stage before implantation, but equivalently expressed shortly thereafter: they are transiently imprinted.nBiX genes are highly expressed in the developing brain and almost all have human counterparts that are associated with disease: many are involved in metabolic and membrane regulation, so their dysregulation manifests in diverse pathologies. Disruption of known imprinted genes is oncogenic, linking imprinted gene regulation and cancer, and there is increasing evidence that epigenetic dysregulation in early embryos results in adult disease: examples include nuclear transfer cloning (which produces obesity and other pathologies) and inter-generational epigenetic inheritance, in which parentally-acquired disease traits become heritable.The present proposal seeks to test the unscrutinised hypothesis that transient disruption of imprinted (particularly nBiX) gene expression during the preimplantation window of uniparental expression causes disease. We will determine at high resolution which traits are dysregulated when nBiX expression levels are briefly disrupted during preimplantation development. This will be accomplished using embryological tools developed by us to increase or reduce nBiX transcript activity at specified stages in mouse preimplantation development.From preliminary analysis, such transient disruption of nBiX expression impedes embryogenesis. We will extend this to a fuller analysis of the pathological consequences of nBiX disruption using molecular, cellular and physiological approaches, as it manifests at all stages pre- and post-implantation, peri-natal development and into adulthood. The mouse studies will be informed by in-depth analysis of parent-specific genome activity in human blastocysts, allowing us to map mouse nBiX dysregulation in disease onto human imprints.There is currently no alternative experimental strategy to the one proposed reversibly to abrogate transient imprinted gene expression and reveal links to disease. The imprinting phenomenon is transient and subtle: H3K27me3 may be displaced long before disease is manifest, requiring new perspectives to study it. The work promises to reveal epigenetically-regulated mechanisms predisposing to cancer, and to establish a new and tractable embryonic model. More broadly it will show how the earliest events in embryonic development can effect epigenetic inheritance of disease traits, informing ART so that it may be adapted to minimise epigenetic contributions that predispose to disease.

哺乳动物细胞通常有两套染色体，一套遗传自母亲，一套遗传自父亲。在大多数情况下，两个亲本基因（等位基因）具有相似的活性，但在一个重要的少数（约占总数的0.5%）中，从一个亲本遗传的等位基因相对于来自另一个亲本的相应等位基因是活跃的。这些基因被认为是印记的，它们的表达平衡对于胚胎存活和避免疾病至关重要。产生印记基因表达的染色质标记可以采取相对稳定的基因组DNA甲基化形式，并且已经知道了大约30年。最近，已经发现，组蛋白，包装基因组DNA，也携带印记，似乎只在植入前发育期间持续;在此之后，来自每个父母等位基因的表达变得equivalent.We最近记录了两种印记类型的小鼠结合父母歧视单胚胎基因组甲基化和基因表达分析。这项工作证实了特征良好的印记，但表明存在多个以前未报道的新印记区域，包括71个称为nBiX的新印记基因（用于新的胚泡印记表达）。小鼠nBiX基因由修饰的组蛋白标记，（组蛋白3中赖氨酸27的三甲基化，H3 K27 me 3），并且在植入前的胚泡阶段单层表达，但在植入后不久同样表达：它们是瞬时印记的。nBiX基因在发育中的大脑中高度表达，并且几乎所有都具有与疾病相关的人类对应物：许多参与代谢和膜调节，因此它们的失调表现为多种病理。已知印迹基因的破坏是致癌的，将印迹基因调控和癌症联系起来，越来越多的证据表明早期胚胎的表观遗传失调会导致成人疾病：例子包括核移植克隆（导致肥胖和其他疾病）和代际表观遗传，在这种情况下，父母获得的疾病特征变得可遗传。目前的建议旨在测试未经审查的假设，即短暂的破坏印记在单亲表达的植入前窗口期间，NBiX（特别是nBiX）基因表达引起疾病。我们将以高分辨率确定当nBiX表达水平在植入前发育期间短暂中断时哪些性状失调。这将使用我们开发的胚胎学工具来实现，以增加或减少小鼠植入前发育中特定阶段的nBiX转录活性。我们将使用分子，细胞和生理方法对nBiX破坏的病理后果进行更全面的分析，因为它在植入前和植入后，围产期发育和成年期的所有阶段都表现出来。小鼠研究将通过对人类胚泡中父母特异性基因组活性的深入分析获得信息，使我们能够将疾病中的小鼠nBiX失调映射到人类imprints.There目前还没有替代实验策略来可逆地废除瞬时印记基因表达并揭示与疾病的联系。印记现象是短暂而微妙的：H3 K27 me 3可能在疾病表现出来之前很久就被取代了，需要新的视角来研究它。这项工作有望揭示癌症易感的表观遗传调控机制，并建立一个新的易处理的胚胎模型。更广泛地说，它将显示胚胎发育中最早的事件如何影响疾病性状的表观遗传，为ART提供信息，以便它可以适应最小化易患疾病的表观遗传贡献。

项目成果

A program of successive gene expression in mouse one-cell embryos

• DOI: 10.1016/j.celrep.2023.112023
• 发表时间: 2023-01-31
• 期刊: CELL REPORTS
• 影响因子: 8.8
• 作者: Asami, Maki;Lam, Brian Y. H.;Perry, Anthony C. F.
• 通讯作者: Perry, Anthony C. F.