Control of TGF-beta signals by Rab23 and Megf8 in mammalian left-right patterning

Rab23 和 Megf8 在哺乳动物左右模式中控制 TGF-β 信号

• 批准号: 9753312
• 负责人: JONATHAN T EGGENSCHWILER
• 金额: $ 7.5万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9753312
• 关键词: Address; Affect; Biochemical; Biological Assay; Biophysics; Body Patterning; Carpenter' s Syndrome; Categories; Cells; Cilia; Congenital Abnormality; Congenital Heart Defects; Data; Defect; EGF gene; Embryo; Embryonic Development; Environment; Exhibits; Failure; Family member; Feedback; Gene Expression; Genes; Handedness; Health; Heart; Human; Laboratories; Lateral; Left; Liquid substance; Lung; Mammals; Mesoderm; Mesoderm Cell; Microscopy; Modeling; Molecular; Morphogenesis; Morphology; Mus; Mutation; Nodal; Organ; Pathologic; Pathway interactions; Patients; Pattern; Positioning Attribute; Process; Production; Proteins; Rare Diseases; Research Subjects; Role; Rotation; Side; Signal Transduction; Structure; Testing; Transforming Growth Factor beta; Translating; Vesicle; Visceral; Work; Zebrafish; base; cilium motility; clinically relevant; congenital heart disorder; experimental study; extracellular; fluid flow; growth differentiation factor 1; in vivo; inhibitor/antagonist; lipofection; phenotypic data; programs; protein transport; trafficking

Project Summary Failure to properly pattern the left-right axis of the human embryonic body plan results in a variety of birth defects, including the most common category of human birth defects, congenital heart defects. Despite the importance of left-right patterning of the body plan for human health, the mechanisms that generate it are only partially understood. Left-right patterning in mammals begins in the node where symmetry breaking occurs by the rotation of motile cilia, which causes a leftward fluid flow. Cells on the left side of the node sense this asymmetry and respond, through a process that remains largely unclear, by signaling to the lateral plate mesoderm (LPM) cells on the left side of the body. The signals used are the TGF-β family members Nodal and GDF-1. In the LPM, Nodal induces its own expression, which propagates through the left LPM, as well as the expression of its inhibitors, Lefty1 and Lefty2. Activation of the Nodal pathway in the left LPM drives morphological asymmetry with respect to the placement of visceral organs as well as structural asymmetries with an organ (e.g., the heart and lungs). Our data indicate the vesicle trafficking protein Rab23 is critical for the production of functional TGF-β signals that relay information to the left LPM in both mouse and zebrafish. Our data indicate that Rab23 functions in both the node and the LPM and that cells of the left node may respond to asymmetric fluid flow by regulating the level of Rab23 activity. Under this model, active Rab23 traffics Nodal and GDF-1 proteins through the secretory pathway so they may be processed and efficiently released to signal cells in the left LPM. This second part of the model is the subject of the research proposed here. Based on human and mouse phenotypic data, we hypothesize that this process also involves the multiple EGF-repeat protein Megf8. Under the current proposal, a set of three aims will address fundamental aspects of this model. Under the first aim, the mechanism by which Rab23 regulates Nodal/GDF-1 trafficking and secretion will be investigated using microscopy and biochemical approaches. Under the second aim, we will determin the localization of Rab23 and Nodal in the embryo proper. Under the final aim, we will investigate the hypothesis that Megf8 functions together with Rab23 to control trafficking and secretion of the TGF-beta signals Nodal and GDF-1. Collectively, these experiments will provide the basis for addressing the long-standing question in the left-right patterning field regarding how biophysical information in the form of cilium-driven fluid flow is translated into asymmetric gene expression and, subsequently, asymmetric morphogenesis of the internal organs.

项目摘要 未能正确地图案化人类胚胎身体计划的左右轴导致各种 出生缺陷，包括人类出生缺陷中最常见的一类，先天性心脏缺陷。 尽管身体的左右模式对人类健康很重要，但 产生它只是部分理解。哺乳动物的左右模式始于节点， 通过运动纤毛的旋转而发生对称性破坏，这导致了非对称性流体流动。细胞对 左侧的节点感觉到这种不对称性，并作出反应，通过一个过程，在很大程度上仍然不清楚， 通过向身体左侧的侧板中胚层（LPM）细胞发出信号。使用的信号是 TGF-β家族成员Nodal和GDF-1。在LPM中，Nodal诱导其自身的表达， 通过左侧LPM传播，以及其抑制剂Lefty 1和Lefty 2的表达。激活 左侧LPM中的Nodal通路的位置驱动相对于 内脏器官以及与器官的结构不对称（例如，心脏和肺）。 我们的数据表明，囊泡运输蛋白Rab 23对功能性细胞因子的产生至关重要。 在小鼠和斑马鱼中，TGF-β信号将信息传递到左侧LPM。我们的数据表明 Rab 23在节点和LPM中都起作用，并且左节点的细胞可以响应于不对称的LPM。 通过调节Rab 23活性水平来调节液体流动。在这种模式下，主动Rab 23业务节点和 GDF-1蛋白通过分泌途径，因此它们可以被加工并有效地释放， 左侧LPM中的信号细胞。模型的第二部分是这里提出的研究主题。 基于人类和小鼠的表型数据，我们假设这一过程也涉及到 多EGF重复蛋白Megf 8。 根据目前的建议，一套三个目标将涉及这一模式的基本方面。 在第一个目标下，Rab 23调节Nodal/GDF-1运输和分泌的机制将 使用显微镜和生物化学方法进行研究。在第二个目标下，我们将确定 Rab 23和Nodal在胚胎中的定位。根据最终目标，我们将调查 Megf 8与Rab 23一起控制TGF-β的运输和分泌的假说 信号节点和GDF-1。 总的来说，这些实验将为解决长期存在的问题提供基础 关于纤毛驱动的流体流动形式的生物物理信息如何 翻译成不对称的基因表达，随后，不对称的形态发生的 内脏