Transcriptional regulation of liver specification in Xenopus tropicalis

热带爪蟾肝脏规格的转录调控

基本信息

批准号：
8119663
负责人：
Andrea Elizabeth Wills
金额：
$ 5.13万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-07-01 至 2013-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8119663
关键词：
Address Anterior Antibodies Basic Science Binding Biochemical Biological Models Cardiac Cells Collaborations Commit Communities Competence Cues Databases Development Diagnosis Dose Embryo Endoderm Expressed Sequence Tags FGFR4 gene Fibroblast Growth Factor Fostering Gene Expression Gene Targeting Genes Genetic Goals Hepatic Hepatocyte In Situ Hybridization Injection of therapeutic agent Investigation Length Link Liver Liver diseases Mediating Mesoderm Methodology Mus Neurula Nodal Oligonucleotides Organ Organogenesis Orthologous Gene Pattern Primitive foregut structure Process Program Development Proteins Protocols documentation Rana Regulation Research Screening procedure Signal Transduction Signaling Molecule Specific qualifier value Staging Structure of septum transversum Testing Therapeutic Time Training Transcriptional Regulation Transplant Recipients Western Blotting Xenopus cell motility cell type chromatin immunoprecipitation embryonic stem cell extracellular human embryonic stem cell in vivo inhibitor/antagonist insight liver transplantation loss of function novel overexpression precursor cell public health relevance transcription factor

项目摘要

DESCRIPTION (provided by applicant): The establishment of a committed cell fate from a pluripotent precursor cell requires the coordinated integration of cell autonomous and non-autonomous cues through time. In the case of the liver, hepatic cell fate is thought to be acquired through a sequential process of commitment: cells are first directed to an endoderm fate by extracellular Nodal signaling, then acquire liver competence through the expression of specific transcription factors such as Gata4 and FoxA1, then are restricted from developing into other anterior endoderm organs by the action of extracellular signals including BMP signals from the septum transversum and FGF signals from the cardiac mesoderm. The goal of this research is to answer three unresolved questions in liver fate specification: which of the direct targets of Nodal signaling act in establishing liver competence; what are the direct targets of FoxA1; and what is the in vivo mechanism by which BMP and FGF regulate hepatic induction? These questions address gaps in our understanding of the transcriptional hierarchy through which known factors in liver development act, and of how each stage of liver development is mechanistically linked to the next. Answering these questions directly requires large numbers of embryos at early developmental stages, a limitation of amniote model systems where many previous studies on liver development have been conducted. Therefore, the proposed research will be carried out in the frog Xenopus tropicalis, which has large numbers of readily manipulated embryos ideal for rapid screening and biochemical investigations. The proposed project will generate a database of in situ hybridization expression patterns representing Nodal signaling targets, which will be made available to the community. The proposed project will also entail training and the development of expertise in recently-developed biochemical and high-throughput sequencing methodologies, specifically including the adaptation of existing protocols for chromatin immunoprecipitation and high throughput sequencing (ChIP-Seq) for use in X. tropicalis embryos with FoxA1 antibodies. Finally, this project will foster collaborations between basic research carried out in X. tropicalis and applications of the findings to directed differentiation of human embryonic stem cells to liver fates. The answers to these questions will elaborate our understanding of liver organogenesis, and will have applications to the development of new protocols for deriving hepatocytes from embryonic stem cells, a major goal for the eventual treatment of liver disease. PUBLIC HEALTH RELEVANCE: Understanding the steps that occur as a cell changes from a pluripotent fate to a liver fate during normal embryological development has and will continue to directly inform efforts to control the differentiation of human embryonic stem cells to liver cells. Liver cells derived from embryonic stem cells or other non-liver cell types are a potential therapeutic alternative to liver transplant for patients suffering from liver diseases. Further, a mechanistic understanding of the stages of liver development will provide insight into the genetic or developmental origins of some liver diseases arising from improper execution of the liver development program, and how they could be diagnosed or treated.

描述（由申请人提供）：从多能前体细胞中建立授权的细胞命运，需要随着时间的推移协调单元自主和非自主提示的协调整合。 In the case of the liver, hepatic cell fate is thought to be acquired through a sequential process of commitment: cells are first directed to an endoderm fate by extracellular Nodal signaling, then acquire liver competence through the expression of specific transcription factors such as Gata4 and FoxA1, then are restricted from developing into other anterior endoderm organs by the action of extracellular signals including BMP signals from the septum transversum和心脏中胚层的FGF信号。这项研究的目的是回答肝脏命运规范中的三个未解决的问题：建立肝脏能力时，淋巴结信号传导的哪个直接目标； FOXA1的直接目标是什么？ BMP和FGF调节肝诱导的体内机制是什么？这些问题解决了我们对转录层次结构的理解中的差距，通过这些层次结构，肝脏发育中已知的因素以及肝脏发育的每个阶段与下一个阶段的关系如何。回答这些问题需要在早期发育阶段进行大量胚胎，这是羊膜模型系统的局限性，在这些系统上已经进行了许多先前关于肝脏发育的研究。因此，拟议的研究将在Frog Xenopus Tropicalis中进行，该研究具有大量容易受到操纵的胚胎，非常适合快速筛查和生化研究。所提出的项目将生成代表节点信号目标的原位杂交表达模式的数据库，该模式将提供给社区。拟议的项目还将需要培训并发展最近开发的生化和高通量测序方法，特别是包括适应现有方案的染色质免疫沉淀和高吞吐量测序（CHIP-SEQ），可用于X. Tropicalis胚胎与FoxA1抗体一起使用。最后，该项目将促进X. topicalis中进行的基础研究与调查结果在指示人类胚胎干细胞分化为肝脏命运的基础研究之间的合作。这些问题的答案将详细说明我们对肝脏器官发生的理解，并将应用于开发新方案，以从胚胎干细胞中衍生肝细胞，这是最终治疗肝病的主要目标。公共卫生相关性：理解随着细胞从多能命运变为正常胚胎学发育期间的肝脏命运而发生的步骤，并将继续直接告知控制人类胚胎干细胞与肝细胞的分化的努力。源自胚胎干细胞或其他非肝细胞类型的肝细胞是患有肝病患者的肝移植的潜在治疗替代品。此外，对肝脏发育阶段的机械理解将为某些肝脏疾病的遗传或发育起源提供洞察力，这是由于肝脏发育计划的执行不当以及如何被诊断或治疗而引起的。