Mechanisms underlying asymmetric rotation and vascular development of the midgut

中肠不对称旋转和血管发育的机制

• 批准号: 8434804
• 负责人: Natasza A Kurpios
• 金额: $ 32.14万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8434804
• 关键词: Actins; Address; Affect; Angioblast; Architecture; Automobile Driving; Behavior; Biological Assay; Biological Models; Birds; Blood; Blood Vessels; Cataloging; Catalogs; Cell Polarity; Cell Shape; Cells; Chickens; Childhood; Congenital Abnormality; Coupled; Cues; Cytoskeleton; Data; Development; Diagnosis; Dorsal; ES Cell Line; Embryo; Embryology; Enzymes; Exhibits; Failure; GTP-Binding Proteins; Gastrointestinal tract structure; Gel; Gene Expression; Gene Expression Regulation; Genes; Genetic; Goals; Heparan Sulfate Proteoglycan; Heparitin Sulfate; Human; Intestinal Volvulus; Intestines; Knockout Mice; Lasers; Lead; Learning; Left; Ligands; Link; Live Birth; Mediator of activation protein; Mesenchymal; Mesenteric Arteries; Mesentery; Microarray Analysis; Midgut; Modification; Molecular; Morphogenesis; Morphology; Mus; Mutant Strains Mice; Neoplasm Metastasis; Organ; Pathway interactions; Patients; Pattern; Physical condensation; Play; Positioning Attribute; Process; Property; Proteins; Publishing; Quail; Randomized; Research; Role; Rotation; Side; Signal Transduction; System; Technology; Testing; Time; Transplantation; Tube; Tubular formation; Vascular blood supply; Vascularization; angiogenesis; base; cell behavior; cellular targeting; chemokine receptor; chromatin immunoprecipitation; egg; extracellular; gene function; genetic manipulation; glypican 3; improved; in vivo; laser capture microdissection; member; molecular asymmetry; mouse model; neonate; novel; research study; rho; tissue repair; tool; transcription factor; tumor progression; vasculogenesis

DESCRIPTION (provided by applicant): Early in development, the midgut must rotate so that its ventral margin shifts to the left; failure to do so results in a malrotation and can lead to catastrophic midgut volvulus. It has long been assumed that gut rotation is intrinsic to the tube itself; however, my research has demonstrated that rotation is instead determined by asymmetric cellular changes within the dorsal mesentery that suspends the gut. This mesentery has four juxtaposed yet distinct cellular compartments distributed along its left-right axis, and changes in each are required for correct gut rotation. Combined with the unique accessibility of the chicken egg, this cellular architecture has established the dorsal mesentery as a powerful model system to define, in vivo, the fundamental genetic and cellular mechanisms through which organs acquire their spatial organization, which is a prerequisite for normal functioning. The genesis of gut rotation traces its origins to the early left-right symmetry-breaking transcription factor Pitx2. In mice and birds, Pitx2 is necessary and sufficient to produce the leftward tilt, and this rotation is randomized in embryos deficient for Pitx2 activity. However, th mechanisms by which this transcription factor directs downstream cellular changes necessary to cause gut rotation remain unknown. To identify cellular targets of Pitx2 in each of the four compartments, we employed laser capture microdissection to isolate then catalog the genes expressed in each cellular compartment at the time of the leftward tilt. Using these data, the firs aim pursues cascades involving subsets of genes that are critical for signaling, for recognizing extracellular cues, and for remodeling cytoskeletal architecture. The roles of key players will be assessed by introducing gain- or reduction- of function gene constructs into each compartment. In our second aim, we address previously unknown asymmetries in the formation of intra-mesenteric arteries that bring blood to the gut, using experimental approaches similar to the first aim but assaying for positive and negative regulators of vasculogenesis. In our third aim, we expand our studies using mouse models of asymmetric organ development and use chromatin immunoprecipitations in vivo to identify bona fide Pitx2 transcriptional targets. Lessons learned from these experiments will impact the study of other regions of the gut, and of tubular organs in general, some of which share strikingly similar features of morphogenesis and genetic patterning with the vertebrate midgut.

描述（由申请人提供）：在发育早期，中肠必须旋转，使其腹侧边缘向左移动;如果不这样做，会导致旋转不良，并可能导致灾难性的中肠扭转。长期以来，人们一直认为肠道旋转是管本身固有的;然而，我的研究表明，旋转是由背肠系膜内的不对称细胞变化决定的。肠系膜有四个并列但不同的细胞隔室，它们沿着其左右轴分布，每个隔室的变化都是正确的肠道旋转所必需的。结合鸡蛋的独特可及性，这种细胞结构已经建立了背肠系膜作为一个强大的模型系统，以定义，在体内，基本的遗传和细胞机制，通过该机制器官获得其空间组织，这是正常运作的先决条件。肠道旋转的起源可以追溯到早期的左-右破坏性转录因子Pitx 2。在小鼠和鸟类中，Pitx 2是产生旋转倾斜所必需的，并且这种旋转在缺乏Pitx 2活性的胚胎中是随机的。然而，这种转录因子引导下游细胞变化引起肠道旋转的机制仍然未知。为了鉴定Pitx 2在四个隔室中的每一个中的细胞靶点，我们采用激光捕获显微切割来分离然后编目在微倾斜时在每个细胞隔室中表达的基因。利用这些数据，第一个目标是追求级联反应，涉及对信号传导、识别细胞外信号和重塑细胞骨架结构至关重要的基因子集。将通过在每个隔室中引入功能基因结构的获得或减少来评估关键参与者的作用。在我们的第二个目标中，我们使用与第一个目标类似的实验方法，解决了以前未知的肠系膜内动脉形成的不对称性，这些动脉将血液输送到肠道 目的是检测血管发生的正性和负性调节因子。在我们的第三个目标，我们扩大我们的研究，使用小鼠模型的不对称器官发育和使用染色质免疫沉淀在体内，以确定真正的Pitx 2转录靶点。从这些实验中吸取的教训将影响肠道其他区域的研究，以及一般的管状器官，其中一些与脊椎动物中肠的形态发生和遗传模式具有惊人的相似特征。