Modeling epithelial stem cell competition in a dynamic Drosophila ovarian niche

动态果蝇卵巢生态位中上皮干细胞竞争的建模

• 批准号: 8638978
• 负责人: Todd Nystul
• 金额: $ 29.05万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8638978
• 关键词: Adherens Junction; Adult; Anterior; Apical; Architecture; Cell Adhesion; Cell Adhesion Molecules; Cell Cycle; Cell Differentiation process; Cell Lineage; Cell Maintenance; Cell Polarity; Cell-Cell Adhesion; Cells; Complex; Cyst; Data; Daughter; Development; Diagnostic Neoplasm Staging; Disease; Disease Progression; Drosophila genus; Environment; Epithelial; Epithelium; Female; Fostering; Foundations; Genes; Genetic; Genetic Epistasis; Germ Cells; Goals; Health; Homeostasis; Image; Immunofluorescence Immunologic; Label; Larva; Lateral; Lethal Genes; Life; Malignant Neoplasms; Mammals; Measures; Mediating; Mission; Modeling; Oogenesis; Ovarian; Ovary; Population; Positioning Attribute; Process; Proteins; Public Health; Publishing; Regenerative Medicine; Regulation; Research; Resolution; Role; Stem cells; Stromal Cells; Study models; Surface; Techniques; Testing; Tissues; United States National Institutes of Health; adult stem cell; base; cancer therapy; cell fate specification; cell type; daughter cell; follow-up; improved; in vivo; innovation; male; member; mutant; novel; progenitor; stem cell biology; stem cell division; stem cell fate; stem cell niche; theories

DESCRIPTION (provided by applicant): This proposal outlines a strategy for defining key components of a novel type of dynamic stem cell niche in the Drosophila ovary and for elucidating the mechanism of competition for niche occupancy. Accomplishing the aims in this proposal will be an important milestone toward the long-term goal of building a detailed model of epithelial stem cell regulation in order to develop regenerative medicine-based therapies and understand how the regulatory process fails in disease states such as cancer. The follicle stem cells (FSCs) that produce follicular epithelia have many features in common with mammalian epithelial progenitors and will likely be an excellent model for epithelial stem cell biology. Like several other types of epithelial stem cells in Drosophila and mammals, FSCs are stably maintained in the tissue but do not appear to be supported by a fixed, non- dividing niche cell population. Instead, putative niche cells divide during adulthood, and the position of the niche changes as surrounding germ cell cysts move through oogenesis. In addition, FSC daughters regularly migrate between niches and compete for niche occupancy in a process that may have broad relevance both to normal epithelial homeostasis and the early stages of cancer. However, the identity of the putative niche cells and the mechanisms that mediate stem cell maintenance and niche competition are unknown. Based on published studies and significant preliminary data, the central hypothesis of the proposal is that differences in cell adhesion and cell polarity cause FSC and daughter cell fates to diverge. Specific aims include: (1) Identifying the dynamic FSC niche cells, determining their lineage, and measuring their rate of turn over; (2) Elucidating the role of cell adhesion in FSC maintenance and FSC niche competition; and (3) Elucidating the role of cell polarity in the specification of FSC versus daughter cell fate. To achieve the first aim, cell-type-specific markers, lineage analysis, and cell cycle markers will be used to identify putative niche cells and measure their rate of turnover, and results will be confirmed with live imaging. To achieve the second and third aims, immunofluorescence will be used to identify cell adhesion and cell polarity proteins that are expressed in the FSC niche, and mosaic analysis will be used to determine their function in FSC maintenance and competition. This project is significant because it will establish a new model for the study of epithelial stem cell niches. It is an innovative departure from previous studies that focuses on building a comprehensive model of the FSC niche and on understanding the novel concepts of the dynamic niche, niche competition and stem cell-specific polarity. Ultimately, it will provide a foundation for understanding conserved mechanisms of in vivo epithelial stem cell regulation.

描述（由申请人提供）：该提案概述了一种用于定义果蝇卵巢中新型动态干细胞生态位的关键组分和阐明生态位占据竞争机制的策略。实现该提案中的目标将是实现建立上皮干细胞调控详细模型的长期目标的重要里程碑，以便开发基于再生医学的疗法，并了解调控过程如何在癌症等疾病状态中失败。产生滤泡上皮的滤泡干细胞（FSC）具有许多与哺乳动物上皮祖细胞相同的特征，可能是上皮干细胞生物学的极好模型。与果蝇和哺乳动物中的几种其他类型的上皮干细胞一样，FSC稳定地维持在组织中，但似乎不受固定的非分裂小生境细胞群的支持。相反，假定的生态位细胞在成年期分裂，随着周围生殖细胞包囊在卵子发生过程中的移动，生态位的位置发生变化。此外，FSC子体定期在小生境之间迁移，并在可能与正常上皮稳态和癌症早期阶段都具有广泛相关性的过程中竞争小生境占用。然而，假定的小生境细胞的身份和介导干细胞维持和小生境竞争的机制是未知的。基于已发表的研究和重要的初步数据，该提案的中心假设是细胞粘附和细胞极性的差异导致FSC和子细胞命运分歧。具体目标包括：（1）鉴定动态FSC生态位细胞，确定其谱系，并测量其周转率;（2）阐明细胞粘附在FSC维持和FSC生态位竞争中的作用;和（3）阐明细胞极性在FSC相对于子细胞命运的特化中的作用。为了实现第一个目标，将使用细胞类型特异性标志物、谱系分析和细胞周期标志物来识别推定的小生境细胞并测量其周转率，并将使用实时成像来确认结果。为了实现第二个和第三个目标，免疫荧光将被用来识别细胞粘附和细胞极性的蛋白表达在FSC的小生境，和马赛克分析将被用来确定它们的功能，在FSC的维护和竞争。本研究为上皮干细胞微环境的研究建立了新的模型，具有重要意义。这是一个创新的出发点，从以往的研究，重点是建立一个全面的模型FSC生态位和理解的动态生态位，生态位竞争和干细胞特异性极性的新概念。最终，它将为了解体内上皮干细胞调控的保守机制提供基础。