How does signaling induce human primordial germ cells?

信号传导如何诱导人类原始生殖细胞？

• 批准号: MR/N020979/1
• 负责人: Andrew Johnson
• 金额: $ 90.24万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FN020979%2F1
• 关键词: How; does; signaling; induce; human

Primordial germ cells (PGCs) are the cells in an embryo that later become egg and sperm in adults, and they form in the early stages of an embryo's development. Understanding the molecular/genetic mechanism that controls PGC development is important for assisted reproduction, technologies, understanding the origins germ line cancers, and for regenerative medicine. However, to date little is known about how PGCs development in humans is controlled. Indeed, understanding how cells in an embryo decide to become PGCs, in vertebrates, generally, has posed a unique challenge to biologists for reasons that are only now becoming clear. At its heart is the process of evolution, and how evolutionary forces have affected the mechanisms for PGC development. Because, while many mechanisms that control development have been worked out in embryos of simpler animals, like those of frogs or fish, it has not been possible to use these species as "models" for human PGC development. This is because each of the model organisms typically studied in laboratories has evolved a unique mechanism for producing PGCs. Humans, in contrast, employ what is apparently the original mechanism that evolved in vertebrates to produce PGCs, the so-called conserved mechanism. We recognized this problem several years ago, and to explain it we developed a novel theory of evolution concerning the relationship between PGCs and the other cells in an embryo, known as somatic cells. We hypothesized that human embryos retain the mechanism for PGC development that originally evolved in vertebrates, the so-called conserved mechanism. A major component of this theory is, also, that PGCs are derived from the same cells as somatic cells, not from specialized cells. To test this theory, the MRC funded development of an experimental system using embryos from axolotls, a salamander. Axolotls were chosen because they resemble the first vertebrates to move onto land, in other words, the amphibian ancestor to mammals. We predicted that axolotls and humans would share the same mechanism for PGC development, and axolotl embryos could therefore be used as an experimental model to unpick the mechanisms driving this process. We determined the signals that govern PGC development in axolotls, and then considered a an established genetic pathway known to act downstream of these signals in other cell types. From this we identified a principle role for the transcription factor Elk-1, and its functional partner Med23, in PGC development. Elk-1 was discovered over 25 years ago, but its role in embryos has never been clearly determined because commonly studied animal models, including mice, evolved genetic circuits that circumvent its ancient role in embryos. We showed that the pathway discovered in axolotls also controls development of PGCs in pigs, whose embryos accurately model those of humans, strongly suggesting that the role for Elk-1/Med23 that we discovered also directs development of human PGCs. Our proposal is designed to use axolotl embryos to define the biochemical and genetic mechanisms controlling the conserved pathway for vertebrate PGC development. We propose to reduce the activity of Elk-1 or Med23, and replace these proteins with mutant molecules lacking specific biochemical functions. We will also identify all of the genes either up or down-regulated by Elk-1/Med23 that control the distinction of PGCs from somatic cells. We will also test the function of Elk-1/Med23 using newly developed methods to induce PGC-like cells from human embryonic stem cells (hESC), and we will use this hESC system to identify the genetic elements responsible for switching-on genes that regulate human of PGC development. This will be a step towards defining the conserved network of gene required for vertebrate PGC development, enhancing our ability to understand and manipulate germ cells to address issues concerning human health.

原始生殖细胞（PGCs）是胚胎中的细胞，后来在成人中成为卵子和精子，它们形成于胚胎发育的早期阶段。了解控制PGC发育的分子/遗传机制对辅助生殖、技术、了解生殖系癌症的起源和再生医学都很重要。然而，到目前为止，人们对人类PGCs的发育是如何控制的知之甚少。事实上，了解脊椎动物胚胎中的细胞如何决定变成PGCs，对生物学家来说是一个独特的挑战，原因直到现在才变得清楚。它的核心是进化过程，以及进化力量如何影响PGC发展的机制。因为，虽然许多控制发育的机制已经在更简单的动物的胚胎中被研究出来，比如青蛙或鱼的胚胎，但还不可能用这些物种作为人类PGC发育的“模型”。这是因为在实验室中研究的每一种典型的模式生物都进化出了一种产生PGCs的独特机制。相比之下，人类显然采用了脊椎动物进化出来的原始机制来产生PGCs，即所谓的保守机制。我们几年前就认识到了这个问题，为了解释这个问题，我们提出了一种新的进化理论，涉及胚胎中PGCs和其他细胞之间的关系，也就是体细胞。我们假设人类胚胎保留了最初在脊椎动物中进化的PGC发育机制，即所谓的保守机制。这一理论的一个主要组成部分是，PGCs与体细胞一样来自相同的细胞，而不是来自特殊的细胞。为了验证这一理论，MRC资助了一项实验系统的开发，该系统使用了蝾螈的胚胎。之所以选择蝾螈，是因为它们与最早登陆陆地的脊椎动物相似，换句话说，它们是哺乳动物的两栖动物祖先。我们预测，美西螈和人类具有相同的PGC发育机制，因此美西螈胚胎可以作为实验模型来揭示驱动这一过程的机制。我们确定了控制蝾螈PGC发育的信号，然后考虑了在其他细胞类型中已知的作用于这些信号下游的既定遗传途径。由此，我们确定了转录因子Elk-1及其功能伙伴Med23在PGC发展中的主要作用。Elk-1早在25年前就被发现了，但它在胚胎中的作用从未被明确确定，因为包括小鼠在内的常用动物模型都进化出了遗传回路，绕过了它在胚胎中的古老作用。我们发现，在蝾螈中发现的通路也控制着猪的PGCs的发育，猪的胚胎准确地模仿了人类的胚胎，这强烈表明我们发现的Elk-1/Med23的作用也指导了人类PGCs的发育。我们的提议旨在利用美西螈胚胎来确定控制脊椎动物PGC发育保守途径的生化和遗传机制。我们建议降低Elk-1或Med23的活性，并用缺乏特定生化功能的突变分子取代这些蛋白。我们还将鉴定所有由Elk-1/Med23上调或下调的基因，这些基因控制着PGCs与体细胞的区分。我们还将使用新开发的方法从人类胚胎干细胞（hESC）中诱导PGC样细胞来测试Elk-1/Med23的功能，并将使用该hESC系统确定负责调节人类PGC发育的基因开关的遗传元件。这将是确定脊椎动物PGC发育所需的保守基因网络的一步，增强我们理解和操纵生殖细胞的能力，以解决与人类健康有关的问题。

项目成果

Detection of Modified Forms of Cytosine Using Sensitive Immunohistochemistry.

• DOI: 10.3791/54416
• 发表时间: 2016-08-16
• 期刊: Journal of visualized experiments : JoVE
• 作者: Abakir A;Wheldon L;Johnson AD;Laurent P;Ruzov A
• 通讯作者: Ruzov A

foxc1a and foxc1b differentially regulate angiogenesis from arteries and veins by modulating Vascular Endothelial Growth Factor signalling

• DOI: 10.1101/417931
• 发表时间: 2018-09
• 期刊: bioRxiv
• 作者: Z. Jiang;Teri Evans;A. M. Savage;M. Loose;T. Chico;F. V. van Eeden;R. Wilkinson

Cancer reversion with oocyte extracts is mediated by cell cycle arrest and induction of tumour dormancy.

• DOI: 10.18632/oncotarget.24664
• 发表时间: 2018-03-23
• 期刊: Oncotarget
• 作者: Saad N;Alberio R;Johnson AD;Emes RD;Giles TC;Clarke P;Grabowska AM;Allegrucci C
• 通讯作者: Allegrucci C

NANOG is required to establish the competence for germ-layer differentiation in the basal tetrapod axolotl.

• DOI: 10.1371/journal.pbio.3002121
• 发表时间: 2023-06
• 期刊: PLoS biology
• 影响因子: 9.8