Illuminating cell hollowing; the mysterious process of seamless tube formation

照亮细胞空洞；

• 批准号: 7806157
• 负责人: Jodi Schottenfeld
• 金额: $ 4.76万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7806157
• 关键词: Address; Affect; Animals; Binding; Biological; Biological Models; Blood Vessels; Blood capillaries; Cancerous; Cell membrane; Cell model; Cell physiology; Cells; Chimeric Proteins; Cytoskeleton; Data; Defect; Drosophila genus; Endothelial Cells; Epithelial; Event; Exhibits; Generations; Genes; Genetic Screening; Growth; Growth Factor; Growth and Development function; Human; Hypoxia; Imaging Techniques; Immune; Immunohistochemistry; Jurkat Cells; Knowledge; Life; Mediating; Membrane; Membrane Protein Traffic; Microscopy; Microtubules; Modeling; Molecular; Molecular Genetics; Mutation; Nutrient; Orthologous Gene; Oxygen; Pathway interactions; Play; Process; Proteins; Public Health; Role; Route; Secretory Vesicles; Series; Shapes; Site; Synapses; System; Techniques; Time; Trachea; Transgenic Organisms; Tube; Tumor Angiogenesis; Vacuole; Vascular Endothelial Growth Factors; Vesicle; Waste Products; Work; Wound Healing; angiogenesis; apical membrane; body system; capillary; cellular imaging; fly; in vivo; insight; mutant; neoplastic cell; neovascularization; neuronal cell body; new growth; positional cloning; therapeutic target; trafficking; tumor; tumorigenesis; vesicle/vacuole

DESCRIPTION (provided by applicant): Cancerous cells release growth factors such as VEGF to induce growth of new blood vessels in their microenvironment. Neovascularization provides oxygen and nutrients to the growing tumor, while removing any waste products and providing an efficient route for the spread of tumor cells to other organ systems. In the absence of angiogenesis, tumors cannot develop more than 3-4 mm in size; hence, angiogenesis has become a therapeutic target. The vertebrate vasculature and Drosophila tracheal system share similar mechanisms of branch sprouting and tube formation, and therefore the tractable Drosophila model system will provide much needed insight into capillary lumenization during angiogenesis. Ultrastructural studies have shown that branch connection points are frequently comprised of "seamless" tubes. Seamless tubes are unicellular tubes that appear doughnut like in cross-section. Endothelial cells in culture form seamless tubes by the fusion of intracellular vacuoles before eventually connecting with other endothelial cells to generate larger tubes with intercellular seams. These observations have led to a "cell hollowing" model of seamless tube formation in which membrane vesicles or vacuoles are targeted to the center of the cell, where they coalesce and fuse to generate an internal apical membrane. This proposal seeks to define the genetic, molecular, and cell biological mechanisms that underlie formation of seamless tubes, taking a two-pronged approach to address this question in the Drosophila tracheal system. First, the process of seamless tube formation will be elucidated by studying mutants identified in a forward genetic screen that exhibit defects in seamless tubes. The second prong of the approach entails live cell imaging studies in which well-characterized and fluorescently-tagged membrane trafficking components are utilized to visualize seamless tube formation in vivo in real time. DIRECT RELEVANCE TO PUBLIC HEALTH: The induction of new blood vessels Is critical for many aspects of growth and development, but particularly important during wound healing and tumorigenesis. This proposal aims to describe the mechanism by which a cell can transform into a tube (such as a blood vessel) using the Drosophila trachea as a model system.

描述（由申请人提供）：癌细胞释放生长因子，如VEGF，以诱导其微环境中新血管的生长。新血管形成为生长中的肿瘤提供氧气和营养，同时清除任何废物并为肿瘤细胞扩散到其他器官系统提供有效途径。在没有血管生成的情况下，肿瘤的大小不能发展超过3-4 mm;因此，血管生成已成为治疗靶点。脊椎动物的脉管系统和果蝇的气管系统具有相似的分支发芽和管形成机制，因此易处理的果蝇模型系统将提供对血管生成期间毛细血管管腔化的急需的了解。超微结构研究表明，分支连接点经常由“无缝”管组成。无缝管是单细胞管，在横截面上看起来像甜甜圈。培养的内皮细胞通过细胞内空泡的融合形成无缝管，然后最终与其他内皮细胞连接以产生具有细胞间接缝的较大管。这些观察结果导致了无缝管形成的“细胞中空化”模型，其中膜囊泡或空泡被靶向细胞的中心，在那里它们合并并融合以产生内部顶端膜。该提案旨在确定无缝管形成的遗传，分子和细胞生物学机制，采取双管齐下的方法来解决果蝇气管系统中的这个问题。首先，无缝管形成的过程将通过研究在正向遗传筛选中鉴定的突变体来阐明，所述突变体在无缝管中表现出缺陷。该方法的第二个方面需要活细胞成像研究，其中利用良好表征和荧光标记的膜运输组分来可视化体内真实的无缝管形成。 与公共卫生的直接关系：新血管的诱导对于生长和发育的许多方面至关重要，但在伤口愈合和肿瘤发生期间尤为重要。该提案旨在以果蝇气管为模型系统，描述细胞转化为管道（如血管）的机制。