Morphogenesis of mammalian gut endoderm

哺乳动物肠道内胚层的形态发生

• 批准号: 7699919
• 负责人: ANNA-KATERINA HADJANTONAKIS
• 金额: $ 42.72万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7699919
• 关键词: Adult; Bladder; Cell Differentiation process; Cells; Complex; Conceptus; Defect; Development; Disease Progression; Ectoderm; Embryo; Endoderm; Endoderm Cell; Epiblast; Event; Exhibits; Extraembryonic Structure; Fetal Tissues; Gastrointestinal tract structure; Gastrula; Genetic; Germ Layers; Green Fluorescent Proteins; Image; Image Analysis; Imaging Techniques; Intestines; Knowledge; Label; Life; Liver; Lung; Mammals; Maps; Mediating; Mesoderm; Modeling; Molecular; Morphogenesis; Mus; Organ; Pancreas; Placenta; Play; Population; Proteins; Reporter; Role; Signal Transduction; Staging; Stomach; Structure; Testing; Thymus Gland; Thyroid Gland; Tissues; Tube; Visceral; Yolk Sac; body system; cell behavior; cell motility; cell type; design; embryo tissue; gastrulation; mutant; novel; novel therapeutics; public health relevance; respiratory; segregation

DESCRIPTION (provided by applicant): The gut endoderm gives rise to the major cell types of many internal organs, including the thyroid, thymus, lung, stomach, liver, pancreas, intestine and bladder. A rigorous understanding of normal gut endoderm morphogenesis, including knowledge of the origin, commitment, specification and differentiation of cells generating gut endoderm and its derivative tissues, should underpin logical efforts to understand disease progression and design new therapeutic strategies for these vital organ systems. The prevailing view of germ layer formation in mammalian embryos is that ectoderm, mesoderm and gut endoderm derive solely from the epiblast during gastrulation and while extraembryonic tissues interact with the epiblast to establish the body axes, they contribute solely to extraembryonic structures, such as the yolk sac and placenta. The cell movements underlying the morphogenesis of the gut endoderm, the tissue that gives rise to the respiratory and digestive tracts and associated organs such as the lungs, liver and pancreas, are complex and not well understood. Using live imaging combined with genetic labeling, we have begun to investigate the role of the visceral endoderm, a presumed extraembryonic tissue, in gut endoderm formation in the mouse (Figure 1). Three key findings arise from our preliminary studies. (1) A new model for gut endoderm morphogenesis in the mouse, incorporating a novel morphogenetic mechanism resulting in extensive mixing of embryonic and extraembryonic cells. (2) The stereotypical congregation of extraembryonic (visceral) endoderm cells around signaling centers of the gastrula stage embryo. (3) The segregation of extraembryonic and embryonic tissues, a fundamental feature of mammalian development, may not be as strict as believed, and the visceral endoderm, a lineage defined as exclusively extraembryonic, may contribute cells to the embryo-proper. These questions will be explored in the following three Specific Aims. Figure 1: Combining live imaging and genetics in mice to investigate gut endoderm formation in mammals. Live imaging and genetic labeling of the visceral endoderm, and its derivatives in mouse embryos. At embryonic day (E) 6.5 the entire visceral endoderm is labeled with a green fluorescent protein (GFP) reporter. GFP protein reveals a dispersed population of visceral endoderm-derived cells present in the embryonic region of the conceptus at E7.5, which by E8.75 become incorporated into the gut tube of the embryo (A,B). Specific Aim 1: To elucidate the cell behaviors that mediate gut endoderm morphogenesis. We will use both existing and new reporter strains to visualize cell dynamics in wild type embryos and mutants that exhibit endoderm defects. Specific Aim 2: To determine the sequence of events leading to the organization of extraembryonic (visceral) endoderm cells around signaling centers of the mouse gastrula, and test the hypothesis that this arrangement is central to the function of these signaling centers. This will be achieved using live imaging and the analysis of mutants that fail to generate midline structures. Specific Aim 3: To determine if a lineage relationship exists between the visceral endoderm and the gut endoderm tissues of the fetus and adult mouse. We will establish if the visceral endoderm is a transient or stable component of embryonic and adult gut endoderm derived tissues. We will test the hypothesis that extraembryonic (visceral) endoderm is not an exclusively extraembryonic tissue using a genetic induced fate mapping approach. PUBLIC HEALTH RELEVANCE: The gut endoderm gives rise to the major cell types of many internal organs, including the thyroid, thymus, lung, stomach, liver, pancreas, intestine and bladder. A rigorous understanding of normal gut endoderm morphogenesis, including knowledge of the origin, commitment, specification and differentiation of cells generating gut endoderm and its derivative tissues, should underpin logical efforts to design new therapeutic strategies for this vital organ system. The prevailing view of germ layer formation in mammalian embryos is that ectoderm, mesoderm and gut endoderm derive solely from the pluripotent epiblast during gastrulation, and while extraembryonic tissues interact with the epiblast to establish the body axes, they contribute solely to extraembryonic structures, such as the yolk sac and placenta. Our preliminary studies challenge this view, and inform the hypotheses to be tested through the Specific Aims of this proposal. Three key findings arise from our preliminary studies in mice. (1) A new model for gut endoderm formation in the mouse, incorporating a novel morphogenetic mechanism resulting in extensive mixing of embryonic and extraembryonic cells. (2) The stereotypical congregation of extraembryonic (visceral) endoderm cells around signaling centers of the gastrula stage embryo. (3) The segregation of extraembryonic and embryonic tissues, a fundamental feature of mammalian development, may not be as strict as believed, and the visceral endoderm, a lineage defined as exclusively extraembryonic, may contribute cells to the embryo-proper. The broad aim of this project is to use a combination of molecular, embryological and live imaging techniques to investigate the role played by the visceral endoderm, a presumed extraembryonic lineage, in the morphogenesis of the mammalian gut endoderm, the tissue that will give rise to the respiratory and digestive tracts, and associated organs such as lungs, liver and pancreas. In Aim 1, we will define the cell behaviors that mediate gut endoderm morphogenesis in the embryo. We will use both existing and new reporter strains to visualize cell dynamics in wild type embryos and mutants that exhibit endoderm defects. In Aim 2, we will determine the sequence of events leading to the organization of extraembryonic (visceral) endoderm cells around signaling centers of the mouse gastrula, and test the hypothesis that this arrangement is central to the function of these signaling centers. This will be achieved using live imaging and the analysis of mutants that fail to generate midline structures. In Aim 3, we will determine if a lineage relationship exists between the visceral endoderm and the gut endoderm tissues of the fetus and adult mouse. We will establish if the visceral endoderm is a transient or stable component of embryonic and adult gut endoderm derived tissues, and will test the hypothesis that extraembryonic (visceral) endoderm is not an exclusively extraembryonic tissue using a genetic induced fate mapping approach.

描述（由申请人提供）：肠内胚层产生许多内部器官的主要细胞类型，包括甲状腺，胸腺，肺，肺，胃，肝脏，胰腺，胰腺，肠和膀胱。对正常肠道内胚层形态发生的严格理解，包括对产生肠道内胚层及其衍生物组织的细胞的承诺，规范和分化的了解，应支持逻辑上的逻辑努力，以了解这些重要器官系统的疾病进展并设计新的治疗策略。哺乳动物胚胎中生殖层形成的流行视图是，外胚层，中胚层和肠内胚层仅源自胃肠周期间的层状细胞，而胚胎外组织与层状组织相互作用以建立身体轴，它们仅贡献诸如experembryonic结构，例如Yolk sac和plapenta。肠道内胚层形态发生的基础运动，引起呼吸道和消化道以及相关器官（例如肺，肝脏和胰腺）的组织是复杂的且不充分的。使用实时成像与遗传标记结合使用，我们开始研究内脏内胚层（一种假定的外囊外组织）在小鼠肠内内胚层形成中的作用（图1）。我们的初步研究产生了三个关键发现。 （1）在小鼠中的肠道内胚层形态发生的新模型，结合了一种新型的形态发生机制，导致胚胎和胚外细胞的广泛混合。 （2）在胃阶段胚胎的信号传导中心周围的胚外（内脏）内胚层细胞的刻板印象。 （3）哺乳动物发育的基本特征的外胚和胚胎组织的分离可能不像所认为的那样严格，并且内胚层（一种被定义为唯一的外胚型的谱系）可能会给胚胎培训带来细胞。这些问题将在以下三个特定目标中探讨。图1：将活成像和遗传学组合在一起，研究哺乳动物中的肠内胚层形成。内胚层的实时成像和遗传标记及其在小鼠胚胎中的衍生物。在胚胎日（E）6.5整个内脏内胚层都标有绿色荧光蛋白（GFP）记者。 GFP蛋白揭示了E7.5概念的胚胎区域中存在的内脏内胚层衍生细胞的分散群体，通过E8.75，该细胞被掺入胚胎的肠管（a，b）中。特定目的1：阐明介导肠内胚层形态发生的细胞行为。我们将使用现有和新的报告菌株来可视化表现出内胚层缺陷的野生型胚胎和突变体中的细胞动力学。具体目的2：确定导致小鼠气囊信号传导中心内胚膜（内脏）内胚单细胞组织的事件序列，并检验了这种布置对于这些信号传导中心功能至关重要的假设。这将使用实时成像和未能产生中线结构的突变体的分析来实现。特定目的3：确定内胚层和胎儿和成年小鼠的肠内内胚层组织之间是否存在谱系关系。我们将确定内胚层是否是胚胎和成人肠内内胚层衍生组织的短暂或稳定成分。我们将检验以下假设：外胚膜（内脏）内胚层使用遗传诱导的命运映射方法并不是完全胚胎的组织。 公共卫生相关性：肠道内胚层产生许多内部器官的主要细胞类型，包括甲状腺，胸腺，肺，胃，肝脏，肝脏，胰腺，肠，肠和膀胱。对正常肠道内胚层形态发生的严格理解，包括对产生肠道内胚层及其衍生物组织的细胞的承诺，规范和分化的了解，应支持为该重要器官系统设计新的治疗策略的逻辑努力。 The prevailing view of germ layer formation in mammalian embryos is that ectoderm, mesoderm and gut endoderm derive solely from the pluripotent epiblast during gastrulation, and while extraembryonic tissues interact with the epiblast to establish the body axes, they contribute solely to extraembryonic structures, such as the yolk sac and placenta.我们的初步研究挑战了这一观点，并通过该提案的具体目的来告知要测试的假设。三个关键发现来自我们在小鼠中的初步研究。 （1）一种新的在小鼠中肠道内胚层形成的模型，结合了一种新型的形态发生机制，导致胚胎和胚外细胞的广泛混合。 （2）在胃阶段胚胎的信号传导中心周围的胚外（内脏）内胚层细胞的刻板印象。 （3）哺乳动物发育的基本特征的外胚和胚胎组织的分离可能不像所认为的那样严格，并且内胚层（一种被定义为唯一的外胚型的谱系）可能会给胚胎培训带来细胞。该项目的广泛目的是利用分子，胚胎学和实时成像技术的组合来研究内脏内胚层（假定的胚外谱系）在哺乳动物肠肠内内胚层的形态发生中起作用的作用，该组织将引起呼吸和呼吸和消化型和lunge and lungs and lungs and lungs and lungs and lungs。在AIM 1中，我们将定义介导胚胎中肠内胚层形态发生的细胞行为。我们将使用现有和新的报告菌株来可视化表现出内胚层缺陷的野生型胚胎和突变体中的细胞动力学。在AIM 2中，我们将确定导致小鼠胃中信号传导中心内胚膜（内脏）内胚层细胞组织的事件序列，并检验了这种排列对于这些信号传导中心功能至关重要的假设。这将使用实时成像和未能产生中线结构的突变体的分析来实现。在AIM 3中，我们将确定内胚层和胎儿和成年小鼠的肠内内胚层组织之间是否存在谱系关系。我们将确定内胚层是否是胚胎和成年肠内内胚层衍生组织的瞬时或稳定的成分，并将检验以下假设：外胚膜（内脏）内胚层不是使用遗传诱导的命运图映射方法的唯一的外胚型组织。