GROWTH/DIFFERENTIATION FACTORS IN ORGANOGENESIS

器官发生中的生长/分化因素

• 批准号: 6289073
• 负责人: ALAN PERANTONI
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6289073
• 关键词: carcinogenesis; cell differentiation; developmental genetics; fibroblast growth factor; growth factor receptors; hepatocyte growth factor; histogenesis; kidney neoplasms; mitogens; oncoproteins; renal glomerulus; renal tubule; tissue /cell culture

Morphogenesis and stem cell fate determination are directed by a complex of soluble factors and extracellular matrix interactions in organogenesis. While many of these factors have been defined, there is no comprehensive understanding of the specific molecules that mediate differentiation in any given tissue, the responses that each factor elicits, or the sequence of events required for proper patterning. Accordingly, we have developed in vitro systems for producing and purifying the inductive factors that direct kidney development and for analyzing molecular responses in renal tissues to this induction. Previously, we established a cell line from the ureteric bud epithelium, the renal inductive tissue and precursor for the collecting duct in the adult. These cells grow in a defined medium and secrete a tubule-inducing/inductive activity for metanephric mesenchyme. The inductive factor(s) produced by these cells can be collected from conditioned medium, and one of these has recently been purified. This protein has been shown to mediate both the early events of nephrogenesis, i.e., condensation of mesenchyme and upregulation of wt1, as well as late events, i.e., tubulogenesis and upregulation of lim-1. A second factor, which accelerates tubulogenesis in combination with the first, is also suggested from the purification. As an extension of this work, we have also initiated efforts to characterize events downstream of inductive signaling and specifically those associated with the epithelial conversion of metanephric mesenchyme. For this, we previously showed that Fgf2 can mediate condensation but not tubule formation in explant culture, while Fgf2 in combination with our bud cell line-derived activity can induce complete nephrogenesis. The differences have provided the basis for a direct evaluation of the genes responsible for morphogenesis using differential display methodologies. Tubulogenesis is completed over a 3-day period, so molecular events were evaluated by processing explants after 6, 24, and 72 hrs. Using this approach, we have identified 72 cDNA species, which are specifically regulated in this process, 36 of which are novel. These studies have identified certain signaling pathways that mediate the inductive response and include growth factors, cell-cycle regulatory proteins, protein kinases involved in signal transduction pathways, calcium-binding proteins, transcription factors, and proteins associated with cell adhesion. A picture is gradually emerging from these studies of the specific molecular events that mediate tubule formation downstream from the initiating inductive process. Since the epithelial conversion of metanephric mesenchyme is believed to be targeted in nephroblastic tumorigenesis, causing the accumulation of blastemal stem cells, these studies should provide clues as to the molecular lesions which allow that to occur. - Cell signaling, Kidney, Differentiation, Growth factors, Induction, Organogenesis, Wilms' tumors, Childhood tumors,

形态发生和干细胞命运测定是由可溶性因子的复合物和器官发生的细胞外基质相互作用引导的。尽管已经定义了许多因素，但对介导任何给定组织中分化的特定分子，每个因素引起的响应或适当图案所需的事件序列尚无全面了解。因此，我们开发了用于产生和净化导致肾脏发育并分析肾脏组织中分子反应的电感因子的体外系统。以前，我们从输尿管芽上皮，肾脏电感组织和成人收集导管的前体建立了一条细胞系。这些细胞在定义的培养基中生长，并分泌肾小球间充质的小管诱导/电感活性。这些细胞产生的电感因子可以从条件培养基中收集，并且其中一种已被纯化。该蛋白已被证明可以介导肾病的早期事件，即间质和WT1的上调以及后期事件的缩合，即lim-1的管状发生和上调。从纯化中也提出了第二个因素，该因素与第一个相结合加速了小管。作为这项工作的扩展，我们还开始了努力，以表征归纳信号传导下游的事件，尤其是与质子间质的上皮转化相关的事件。为此，我们先前表明，FGF2可以介导外植体培养物中的凝结，而不能介导小管的形成，而FGF2与我们的芽细胞系衍生活性结合使用可以诱导完全的肾脏形成。差异为直接评估使用差分显示方法对形态发生的基因提供了基础。微管发生在3天的时间内完成，因此在6、24和72小时后通过处理外植体评估了分子事件。使用这种方法，我们已经确定了72种cDNA物种，这些cDNA物种在此过程中受到特定调节，其中36种是新颖的。这些研究已经确定了介导电感反应的某些信号通路，包括生长因子，细胞周期调节蛋白，参与信号转导途径的蛋白激酶，钙结合蛋白，转录因子和与细胞粘附相关的蛋白质。从这些特定分子事件的研究中逐渐出现了一幅图片，这些研究从启动归纳过程中介导下游小管形成。由于据信元素间充质的上皮转化是针对肾细胞肿瘤发生的，从而导致爆炸性干细胞的积累，因此这些研究应提供有关允许这种情况的分子病变的线索。 - 细胞信号传导，肾脏，分化，生长因子，诱导，器官发生，Wilms的肿瘤，儿童肿瘤，