Studies on the dose-dependent functions of TGFbeta-Smad2/3 signalling

TGFbeta-Smad2/3信号的剂量依赖性功能研究

• 批准号: MR/M011194/1
• 负责人: Vasso Episkopou
• 金额: $ 73.06万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FM011194%2F1
• 关键词: Studies; dose; dependent; functions; TGFbeta

The body of an embryo forms an elongated structure with the head at the anterior end followed by the trunk and then the tail at the posterior end. This constitutes the basic body Anterior-Posterior (A-P) axis. Mutation of the gene named Nodal and its associated gene network causes a reduction in, or loss of, the anterior/head of the embryo. Such malformations are rarely viable and these embryos are aborted. Interestingly it has become apparent that reduction of Nodal gene activity causes head truncation, while an embryo without any Nodal does not form any A-P axis structures at all and dies very early after implantation. Therefore, high Nodal levels/activity are required for the formation of the head/anterior and lower for the trunk and even less for the tail/posterior. The focus of our study is to understand the dose-dependent effects of Nodal by analysing factors that are responsible for regulating the levels of Nodal activity within the cells. Nodal is produced by certain cells and secreted into the extracellular space where it diffuses and affects the fate and behaviour of cells that are exposed to it. The diffusion of Nodal creates a gradient with high close to the source and low further away. The cells exposed to Nodal receive it with specific proteins located at their cell surface (receptors). Then this signal travels through the cytoplasm as a relay of protein interactions leading to the modification of specific proteins that enter the nucleus of the cell and bind to a set of target genes on the chromosomes to modulate their expression. This gene activation (and sometimes repression) changes cell fate and behaviour. However, this "signal transduction" pathway is itself regulated in order to control more precisely the extent to which the target genes are affected, e.g. the proportion that are activated, and consequently the fate of the cell receiving the Nodal signal. This regulation is dependent on the balance between a few negative regulatory proteins and a factor that we identified and named Arkadia, which destroys these negative regulatory factors to enhance Nodal signalling. Arkadia therefore makes cells respond as if it they have been exposed to high levels of extracellular Nodal. But we do not yet know whether these factors are actually responsible for head/anterior-tail/posterior axis formation in the whole embryo and if they do indeed change the interpretation of the absolute concentration of Nodal to which cells are exposed.Here we propose to test how the combination of mutations in Nodal regulatory factors including Arkadia affects the development of the head/anterior versus tail/posterior in mouse embryos. Furthermore, we will also create these mutations in mouse embryonic stem cells (ESC) in culture and examine whether these affect their differentiation towards tissues that are associated with the head/anterior and depend on high Nodal signalling. One such tissue is the foregut (anterior gut) which gives rise to the oesophagus, larynx, lung, liver and pancreas. Therefore, the ability to manipulate Nodal activity levels in ESC will facilitate and improve the generation of the above tissues and organs that can be use in regenerative medicine.

胚胎的身体形成一个细长的结构，头在前端，然后是躯干，然后是尾巴在后端。这构成了基本的身体前后（A-P）轴。名为Nodal的基因及其相关基因网络的突变导致胚胎前部/头部的减少或丢失。这种畸形很少能存活，这些胚胎被流产。有趣的是，Nodal基因活性的降低显然会导致头部截断，而没有Nodal的胚胎根本不会形成任何A-P轴结构，并且在植入后很早就死亡。因此，形成头部/前部需要高水平的节/活动，而躯干的节/活动更低，尾巴/后部的节/活动更少。我们的研究重点是通过分析负责调节细胞内Nodal活性水平的因素来了解Nodal的剂量依赖性效应。Nodal由某些细胞产生并分泌到细胞外空间，在那里扩散并影响接触它的细胞的命运和行为。Nodal的扩散产生了一个近源高、远源低的梯度。暴露于Nodal的细胞与位于其细胞表面的特定蛋白质（受体）一起接受它。然后，这个信号作为蛋白质相互作用的继电器穿过细胞质，导致特定蛋白质的修饰，这些蛋白质进入细胞核，并与染色体上的一组靶基因结合，以调节它们的表达。这种基因的激活（有时是抑制）改变了细胞的命运和行为。然而，这种“信号转导”途径本身是受调控的，目的是为了更精确地控制靶基因受影响的程度，例如被激活的比例，从而控制接收Nodal信号的细胞的命运。这种调节依赖于一些负调节蛋白和我们发现并命名为Arkadia的因子之间的平衡，该因子破坏这些负调节因子以增强Nodal信号。因此，Arkadia使细胞产生反应，就好像它们暴露在高水平的细胞外Nodal中一样。但我们还不知道这些因素是否真的对整个胚胎中头/前-尾/后轴的形成负责，也不知道它们是否确实改变了对细胞所暴露的Nodal绝对浓度的解释。在这里，我们提议测试包括Arkadia在内的节点调节因子的突变组合如何影响小鼠胚胎头/前与尾/后的发育。此外，我们还将在培养的小鼠胚胎干细胞（ESC）中产生这些突变，并检查这些突变是否会影响它们向与头部/前部相关并依赖于高节点信号的组织的分化。其中一个组织是前肠（前肠），它产生食道、喉、肺、肝和胰腺。因此，在ESC中操纵节点活性水平的能力将促进和改善上述可用于再生医学的组织和器官的产生。

项目成果

Unveiling the Essential Role of Arkadia's Non-RING Elements in the Ubiquitination Process.

• DOI: 10.3390/ijms231810585
• 发表时间: 2022-09-13
• 期刊: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
• 影响因子: 5.6
• 作者: Birkou, Maria;Delegkou, Georgia N.;Marousis, Konstantinos D.;Fragkaki, Nefeli;Toro, Tamara;Episkopou, Vasso;Spyroulias, Georgios A.
• 通讯作者: Spyroulias, Georgios A.

E2 Partner Tunes the Ubiquitylation Specificity of Arkadia E3 Ubiquitin Ligase.

• DOI: 10.3390/cancers15041040
• 发表时间: 2023-02-07
• 期刊: Cancers
• 影响因子: 5.2

Impact of a Single Nucleotide Polymorphism on the 3D Protein Structure and Ubiquitination Activity of E3 Ubiquitin Ligase Arkadia.

• DOI: 10.3389/fmolb.2022.844129
• 发表时间: 2022
• 期刊: Frontiers in molecular biosciences
• 影响因子: 5
• 作者: Birkou M;Raptis V;Marousis KD;Tsevis A;Bourikas K;Bentrop D;Episkopou V;Spyroulias GA
• 通讯作者: Spyroulias GA

Arkadia-SKI/SnoN signaling differentially regulates TGF-β-induced iTreg and Th17 cell differentiation.

• DOI: 10.1084/jem.20210777
• 发表时间: 2021-11-01
• 期刊: The Journal of experimental medicine
• 作者: Xu H;Wu L;Nguyen HH;Mesa KR;Raghavan V;Episkopou V;Littman DR
• 通讯作者: Littman DR