Investigation of active histone marks as barriers to cell-fate changes during reprogramming

研究活性组蛋白标记作为重编程过程中细胞命运变化的障碍

• 批准号: 494710866
• 负责人: Dr. Eva Hörmanseder
• 金额: --
• 依托单位: Institut für Epigenetik und Stammzellen (IES)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/494710866?language=en
• 关键词: Investigation; active; histone; marks; barriers

Vertebrate eggs have the remarkable ability to induce the reprogramming of somatic cell nuclei to enable the production of all cell types of an organism upon nuclear transfer (NT) 1. This capacity to generate all cell types is referred to as totipotency. During NT, the memory of cells must be fully erased in order to enable efficient reprogramming and the consequent generatation of totipotent cells. This has a fundamental impact on regenerative medicine, as progress in understanding the molecular mechanisms of reprogramming to totipotency could allow the generation of any cell type needed for cell replacement therapies. Despite its enormous potential, the molecular mechanisms that allow or impede the conversion of a differentiated ‘donor’ cell to totipotency are not fully understood. Previously, my research revealed that the low efficiency of cell fate conversion via NT is linked to the retention of donor cell type specific memory of an active transcriptional state stabilized by specific histone modifications, namely H3K4 methylation 2. However, the extent to which ‘active’ transcriptional memory impedes or facilitates NT reprogramming is unknown. The overall goal of this proposal is to address the role of active histone modifications in stabilising differentiated cell fates and therefore preventing efficient reprogramming using Xenopus NT-embryos as a model system. Specifically, in the project presented here we propose to 1) develop ”digital reprogramming”, a novel approach based on machine learning to predict candidate active histone modification signatures as epigenetic barriers to reprogramming. 2) functionally characterise such candidate active histone modifications by addressing whether cell fate conversion upon NT is improved after loss-of-function approaches. Importantly, investigating whether active histone modifications can act as epigenetic barriers during reprogramming will enable us to manipulate and lower these barriers. This knowledge will be key to improve reprogramming efficiencies and allow a robust and complete switch in cell fate. The developed tools and the analysis of epigenetic mechanisms that prevent cell-fate reprogramming will give crucial insights into the mechanisms of cellular memory, which prevent unwanted changes in cell fate during development and that are impaired in disease.

脊椎动物卵具有显著的诱导体细胞核重编程的能力，从而能够在核转移（NT）后产生生物体的所有细胞类型1。这种产生所有细胞类型的能力被称为全能性。在NT期间，细胞的记忆必须被完全擦除，以便能够进行有效的重编程和随后的全能细胞的生成。这对再生医学产生了根本性的影响，因为在理解重新编程为全能性的分子机制方面的进展可以允许产生细胞替代疗法所需的任何细胞类型。尽管其潜力巨大，但允许或阻止分化的“供体”细胞转化为全能性的分子机制尚未完全了解。以前，我的研究表明，通过NT的细胞命运转换的低效率与供体细胞类型特异性记忆的保留有关，该记忆由特定的组蛋白修饰（即H3 K4甲基化2）稳定的活性转录状态。然而，在何种程度上“主动”转录记忆阻碍或促进NT重编程是未知的。该提案的总体目标是解决活性组蛋白修饰在稳定分化细胞命运中的作用，从而防止使用非洲爪蟾NT-胚胎作为模型系统的有效重编程。具体来说，在这里提出的项目中，我们建议1） 开发“数字重编程”，这是一种基于机器学习的新方法，可预测候选的活性组蛋白修饰特征，作为重编程的表观遗传障碍。（二） 通过解决在功能丧失方法后NT上的细胞命运转换是否得到改善，在功能上验证了这种候选的活性组蛋白修饰。重要的是，研究活性组蛋白修饰是否可以在重编程过程中作为表观遗传障碍，将使我们能够操纵和降低这些障碍。这些知识将是提高重编程效率并允许细胞命运稳健和完全转换的关键。所开发的工具和对防止细胞命运重编程的表观遗传机制的分析将为细胞记忆机制提供重要的见解，细胞记忆机制可以防止细胞命运在发育过程中发生不必要的变化，并在疾病中受损。