Branching Morphogenesis of Urinary Epithelia: from Genes to Cellular Behaviors

泌尿上皮细胞的分支形态发生：从基因到细胞行为

• 批准号: 7627933
• 负责人: FRANKLIN D COSTANTINI
• 金额: $ 46.56万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 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 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7627933
• 关键词: Address; Adhesions; Affect; Apoptosis; Artificial Organs; Behavior; Biological Assay; CXCL12 gene; CXCR4 gene; Candidate Disease Gene; Cell Count; Cell Separation; Cells; Chemotactic Factors; Clinical; Complex; Congenital Abnormality; Defect; Development; Duct (organ) structure; Ductal Epithelium; Epithelial; Epithelial Cells; Epithelium; Etiology; Event; GDNF gene; Genes; Genetic; Genitourinary system; Growth; Hypertension; Image; Imaging technology; Individual; Instruction; Kidney; Kidney Diseases; Knock-out; Knockout Mice; Label; Lead; Liver; Location; Mediating; Metanephric Diverticulum; Methods; Mitosis; Modeling; Morphogenesis; Movement; Mutation; Nephrons; Obstruction; Organ; Organ Culture Techniques; Organism; Organogenesis; Pattern; Positioning Attribute; Primordium; Process; Pseudostratified Epithelium; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Relative (related person); Research; Role; Shapes; Signal Transduction; Signaling Pathway Gene; Site; Stem cells; Structure of mesonephric duct; System; Testing; Time; Translating; Ureter; Urinary system; Work; base; behavior influence; blood filter; cell behavior; cell motility; cell type; chemokine; chemokine receptor; genetic manipulation; in vivo; malformation; migration; mouse model; nephrogenesis; prevent; progenitor; public health relevance; repaired; research study; response; three dimensional structure; time use; transcription factor; urinary; urologic

DESCRIPTION (provided by applicant): The formation of a single ureteric bud (UB) at the proper location on the Wolffian duct (WD) is important to make a functional ureter, while complex patterns of UB branching morphogenesis are required for normal renal organogenesis. While many genes involved in these events have been identified, the genetic instructions must be translated into specific cellular responses (for example, mitosis, apoptosis, migration, adhesion) in order to shape and organize a complex 3-D structure like the urinary epithelium. While very little is known about the specific cellular behaviors that underlie epithelial morphogenesis in higher organisms, or how they are controlled, advances in genetic manipulation and imaging technologies now make it feasible to address such questions using mouse models. This project will focus on the cellular events that are regulated by the secreted factor GDNF, which signals through the Ret receptor tyrosine kinase. Ret signaling is needed to make a normal ureter and kidney, but how it influences the behavior of WD and UB epithelial cells in vivo remains to be defined. Ret-expressing cells at the tips of the branching UB are the main progenitors of the collecting duct system epithelium during kidney development, and they arise from a specific region of the Wolffian duct, the "primary tip domain". Recent findings reveal that the primary tip domain is itself generated via Ret-dependent cell movements within the Wolffian duct. This raises several important questions: How are these cell movements controlled, and what is the role of GDNF/Ret signaling in Wolffian duct cell motility and guidance? What other genes and signaling pathways downstream of Ret are involved? Do similar cell movements underlie the growth and branching of the ureteric bud tip epithelium during kidney development? How else may Ret signaling affect the behavior of the epithelial progenitor cells at the UB tips? To address these questions, several methods will be used to genetically modify small numbers of WD or UB cells, and then to examine the effects of these alterations on cell behaviors in organ cultures, using time-lapse imaging, or in vivo. The proposed research should advance the field not only by extending to the cellular level our understanding of the role of GDNF/Ret signaling, but also by providing a paradigm for studying how other signaling systems affect the behavior of urinary epithelial cells during organogenesis. The information gained should also advance our understanding of the etiology of congenital urological and renal malformations, and may suggest new strategies to prevent or treat them. PUBLIC HEALTH RELEVANCE: Understanding how the urinary system achieves its normal size and shape has important clinical implications, as defects can lead to obstruction, impaired function or even absence of the ureters and kidneys. The development of the urinary system affects the number of nephrons (blood-filtering units) that form in the kidney, which may influence the progression of renal diseases and hypertension. An understanding of the genes and cellular events that underlie ureter and kidney development may eventually permit treatments for congenital malformations, repair of damaged organs, or growth of artificial organs.

描述(由申请人提供)：在Wolffian管(WD)的适当位置形成单个输尿管芽(UB)对于形成功能性输尿管非常重要，而UB分支形态发生的复杂模式对于正常的肾脏器官发生是必需的。虽然许多参与这些事件的基因已经被识别，但遗传指令必须被翻译成特定的细胞反应(例如，有丝分裂、凋亡、迁移、黏附)，才能形成和组织像尿路上皮一样的复杂的三维结构。虽然人们对高等生物上皮形态发生背后的特定细胞行为或它们是如何控制的知之甚少，但遗传操作和成像技术的进步现在使利用小鼠模型解决这些问题成为可能。这个项目将专注于由分泌因子GDNF调节的细胞事件，GDNF通过Ret受体酪氨酸激酶发出信号。RET信号是形成正常输尿管和肾脏所必需的，但它如何影响WD和UB上皮细胞在体内的行为仍有待确定。在肾脏发育过程中，位于分支UB顶端的RET表达细胞是集合管系统上皮细胞的主要祖细胞，它们起源于Wolffian管的一个特定区域，即“初级顶端区域”。最近的发现表明，初级TIP结构域本身是通过依赖Ret的细胞在Wolffian导管内的运动而产生的。这提出了几个重要的问题：这些细胞运动是如何控制的，GDNF/Ret信号在Wolffian导管细胞运动和引导中扮演什么角色？Ret下游还涉及哪些基因和信号通路？在肾脏发育过程中，类似的细胞运动是否支持输尿管芽尖上皮的生长和分支？Ret信号还可能如何影响UB尖端上皮祖细胞的行为？为了解决这些问题，将使用几种方法对少量的WD或UB细胞进行基因改造，然后使用延时成像技术或在体内检查这些变化对器官培养中细胞行为的影响。这项拟议的研究不仅应该通过将我们对GDNF/Ret信号作用的理解扩展到细胞水平来推动该领域的发展，还应该通过提供一个范例来研究其他信号系统如何影响器官发生过程中尿路上皮细胞的行为。所获得的信息也应该促进我们对先天性泌尿系和肾脏畸形的病因的理解，并可能为预防或治疗它们提供新的策略。公共卫生相关性：了解泌尿系统如何达到正常的大小和形状具有重要的临床意义，因为缺陷可能导致梗阻、功能受损，甚至缺乏输尿管和肾脏。泌尿系统的发育会影响肾脏中形成的肾单位(血液过滤单位)的数量，这可能会影响肾脏疾病和高血压的进展。对支撑输尿管和肾脏发育的基因和细胞事件的了解，最终可能有助于治疗先天性畸形、修复受损器官或人工器官的生长。