Dynamic Mechanisms of Fate Control during Epithelial Organ Renewal

上皮器官更新过程中命运控制的动态机制

• 批准号: 9247213
• 负责人: Lucy Erin O'brien
• 金额: $ 31.6万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2021-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9247213
• 关键词: Adhesions; Adhesives; Adult; Anatomy; Animals; Apical; Arbitration; Architecture; Basement membrane; Behavior; Cell Differentiation process; Cell division; Cell surface; Cells; Cereals; Collection; Cues; Data; Daughter; Disease; Drosophila genus; Dysplasia; Employee Strikes; Ensure; Epithelial; Epithelium; Equilibrium; Event; Genetic; Goals; Human; Image; Individual; Invertebrates; Knowledge; Label; Lateral; Lead; Light; Link; Maintenance; Mediating; Methodology; Midgut; Modeling; Molecular; Mothers; Nature; Organ; Outcome; Pathology; Pathway interactions; Physiological; Process; Property; Regulation; Resolution; Role; Signal Transduction; Stem cells; Structure; Testing; Therapeutic; Time; Tissues; Vertebrates; Work; adhesion receptor; adult stem cell; base; cell behavior; cell motility; cell type; combat; daughter cell; experimental study; extracellular; genetic manipulation; imaging capabilities; imaging potential; in vivo; innovation; movie; notch protein; novel therapeutics; organ regeneration; promoter; public health relevance; receptor; stem; stem cell biology; stem cell division; stem cell therapy; tissue degeneration; tool; virtual

 DESCRIPTION (provided by applicant): Effective and safe stem cell therapies must build upon knowledge of how stem cells generate precise numbers of differentiated cells to meet the body's needs. In adult organ renewal, each stem cell division triggers a pivotal decision between asymmetric, symmetric-stem, and symmetric-terminal fates. To sustain constant numbers of stem and differentiated cells, these three fate outcomes must be collectively balanced. Conversely, dysplasia or degeneration arises if fate balance is lost. Yet in contrast to the well-studied pathways that execute fate outcomes, the upstream events that decide between fate outcomes are virtually unknown. Our long-term goal is to understand the mechanisms that arbitrate the organ-wide balance of division fates. Toward this goal, here we probe the cellular basis of symmetric and asymmetric fate decisions-in vivo and in real time-by combining live imaging with the versatile genetic tools of Drosophila. Using the adult Drosophila midgut, we have made a path breaking innovation by developing long-term imaging of epithelial renewal at high cellular resolution in live animals. Our methodology enables individual stem cell divisions to be captured in their native context and fate decisions to be visualized in real time. We will investigate three fundamental questions about the cellular and molecular nature of fate decisions. In Aim 1, we ask whether fate decisions are made by the dividing mother stem cell, by equipotent daughter cells, or a combination. Using live imaging, we will directly test the mother-control mechanisms of oriented cell division and fate determinant partitioning, and the daughter-control mechanism of Notch-mediated lateral inhibition. We will evaluate whether different mechanisms bias toward different fates, and examine whether initial fate decisions can be overturned by later-acting mechanisms. Aim 2 builds upon exciting preliminary data those stem cells are motile, which provokes the question of whether motility influences fates by altering proximity to spatially localized signals. We will determine how motility impacts fate decisions, probe the interplay between motility and fate outcomes, and identify the cytoskeletal regulators that instigate motility. In Aim 3, we turn to the adhesion junctions that define epithelal architecture and ask how this multicellular adhesive network integrates into fate decisions. We will separately perturb basal, lateral, and apical adhesion receptors on stem, daughter, and differentiated neighbor cells and parse how distinct receptors on different cell surfaces influence fate decision mechanisms and outcomes. Because epithelial stem cell biology and architecture are broadly conserved, the fate decision mechanisms uncovered here will potentially extend to epithelial organs in vertebrates, including humans. Ultimately, understanding the basic mechanisms that decide between division fates will open new therapeutic avenues to combat stem cell pathologies and promote organ regeneration.

 描述（由适用提供）：有效且安全的干细胞疗法必须基于对干细胞如何产生精确数量分化细胞以满足人体需求的知识。在成人器官更新中，每个干细胞分裂触发不对称，对称词干和对称末端命运之间的关键决策。为了维持恒定数量的茎和分化细胞，这三个脂肪结果必须集体平衡。相反，如果失去脂肪平衡，则会出现异常增生或变性。然而，与执行脂肪结果的经过深入研究的途径相反，决定脂肪结果之间的上游事件几乎是未知的。我们的长期目标是了解仲裁器官范围命运平衡的机制。为了实现这一目标，我们在这里探讨了体内对称和不对称命运决定的细胞基础，并通过将实时成像与果蝇的多功能遗传工具相结合。使用成年果蝇中肠，我们通过在活动物中高细胞分辨率的上皮更新的长期成像进行长期成像，从而打破了创新。我们的方法使各个干细胞分裂 在其本地环境中被捕获，并实时可视化命运决定。我们将研究有关命运决定的细胞和分子性质的三个基本问题。在AIM 1中，我们询问命运决定是由分裂的母细胞，同等子细胞或组合做出的。使用实时成像，我们将直接测试定向细胞分裂和命运确定缩剂分配的母体机制，以及Notch介导的侧向抑制的子控制机制。我们将评估不同的机制是否偏向不同的命运，并检查是否可以通过以后的作用机制来推翻初始命运。 AIM 2建立在令人兴奋的初步数据的基础上，这些干细胞是流动的，这引起了一个问题，即运动是否通过改变与经常局部信号的近端来影响命运。我们将确定运动能力如何影响命运决策，探测运动和命运结果之间的相互作用，并确定启发运动性的细胞骨架调节剂。在AIM 3中，我们转向定义上皮结构的粘合剂连接，并询问该多细胞粘合网络如何整合到脂肪决策中。我们将在茎，女儿和分化的邻居细胞上分别扰动基础，侧面和顶端粘合剂受体，并解析不同细胞表面上的不同受体如何影响 命运决策机制和结果。由于上皮干细胞生物学和结构是广泛保守的，因此这里发现的命运决策机制可能会扩展到包括人类在内的脊椎动物中的上皮器官。最终，了解分裂命运之间决定的基本机制将开放新的治疗途径，以抗击干细胞病理并促进器官再生。