Elucidating the cytoskeletal mechanics in stem cell niche morphogenesis

阐明干细胞生态位形态发生中的细胞骨架力学

• 批准号: 10386101
• 负责人: Bailey Nicole Warder
• 金额: $ 4.68万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10386101
• 关键词: Actomyosin; Address; Adherens Junction; Adopted; Affect; Anterior; Area; Automobile Driving; Behavior; Biological Assay; Biology; Cell Polarity; Cell Shape; Cells; Centrosome; Cues; Cytoskeletal Proteins; Data; Daughter; Defect; Dominant-Negative Mutation; Drosophila genus; Dynein ATPase; Educational process of instructing; Embryonic Development; Ensure; Equilibrium; Exposure to; F-Actin; Feedback; Genetic; Goals; Gonadal structure; Health; Human; Image; Imaging Techniques; Journals; Kinesin; Lasers; Lead; Link; Maintenance; Measures; Mechanics; Mentors; Mentorship; Microtubules; Mitotic spindle; Modeling; Morphogenesis; Morphology; Motor; Myosin ATPase; Myosin Light Chain Kinase; Myosin Type II; Pathway interactions; Play; Process; Proteins; RNA Interference; Reproducibility; Rho-associated kinase; Role; Shapes; Signal Transduction; Source; Structure; Suggestion; System; Techniques; Testing; Time; Tissues; Training; Transgenic Organisms; Work; cell behavior; cell cortex; experimental study; germline stem cells; kinase inhibitor; male; mechanical force; meetings; non-muscle myosin; response; self-renewal; stem cell division; stem cell function; stem cell niche; stem cells; symposium; tissue degeneration; tumor; tumorigenesis

Project Abstract: Defects in stem cell function severely impact human health by inducing tumor formation or tissue degeneration. To maintain a proper balance of self-renewal and differentiation, stem cells rely on signaling cues from their niche, which is the microenvironment in which they reside. It is imperative to understand the intricacies that underlie niche biology to reveal mechanisms that promote normal stem cell function and minimize defects in human health. In many tissues, the niche has a precise and reproducible morphology. However, not much is known about how niche morphology is controlled or how it impacts niche function. This project will use the Drosophila gonad to study the mechanics of niche formation, combining genetic tractability with powerful live- imaging techniques pioneered in the DiNardo lab. In this system, the niche has a distinct morphology defined by a smoothened boundary between the niche and the adjacent stem cells. This boundary is further referred to as the niche periphery. Functionally, the niche plays key roles in regulating stem cell behavior: 1) it is the source for self-renewal cues, 2) it restricts access of these cues to only adjacent cells, and 3) it regulates stem cell division orientation. Preliminary evidence suggests that the smooth niche periphery is crucial to ensure proper division angles for germline stem cells (GSCs), suggesting a link between niche structure and function. Furthermore, F-actin and Myosin II (MyoII) are enriched at the niche periphery, accompanied by tensile forces, suggestive of actomyosin contractility. A key goal for this project is to unveil the role of actomyosin contractility in niche morphogenesis and function (Aim 1). Since niche morphogenesis is highly reproducible, this project will also address upstream mechanisms that robustly polarize F-actin and MyoII to the niche periphery (Aim 2). An intriguing possibility is that mechanical forces exerted on the niche by adherent GSCs induce cytoskeletal polarization along the niche periphery. Preliminary evidence suggests GSC divisions are required for proper niche morphology, and it is known that multiple forces act in concert to drive spindle elongation in a dividing cell. This project will address the Hypothesis that F-actin and MyoII enrichment along the niche periphery is induced by GSC spindle elongation, and is necessary for niche formation and function. A combination of transgenic techniques will be used to manipulate actomyosin contractility, as well as inhibit microtubule motors involved in spindle elongation. This project will potentially unveil a feedback mechanism where stem cells shape the niche that guides their behavior, and will be among the first to describe the mechanisms of shaping a functional niche. The training plan for this project consists of lab work, conference attendance, journal clubs, lab meetings, graduate group seminars, and exposure to teaching and mentoring roles. This work will be completed under the mentorship of Dr. Stephen DiNardo, an expert in Drosophila biology and morphogenesis, with co-mentorship by Dr. Erfei Bi, an expert on Myosin, actomyosin ring formation, and cell polarity.

项目摘要： 干细胞功能缺陷会诱发肿瘤形成或组织退化，严重影响人类健康。 为了维持自我更新和分化的适当平衡，干细胞依赖于来自其自身的信号线索 利基（niche），即它们所居住的微环境。必须了解其中的复杂性 作为利基生物学的基础，揭示促进正常干细胞功能并最大限度地减少缺陷的机制 人类健康。在许多组织中，生态位具有精确且可重复的形态。然而，并没有太多 了解生态位形态如何被控制或它如何影响生态位功能。该项目将使用 果蝇性腺研究生态位形成的机制，将遗传易处理性与强大的活性相结合 DiNardo 实验室首创的成像技术。在这个系统中，生态位具有定义的独特形态 通过利基和相邻干细胞之间的平滑边界。该边界进一步被称为 作为利基外围。从功能上讲，生态位在调节干细胞行为中发挥着关键作用：1）它是 自我更新线索的来源，2）它限制这些线索仅进入相邻细胞，3）它调节干细胞 细胞分裂方向。初步证据表明，光滑的生态位外围对于确保 生殖系干细胞（GSC）的正确分裂角度表明生态位结构和功能之间存在联系。 此外，F-肌动蛋白和肌球蛋白 II (MyoII) 在生态位外围富集，伴随着张力， 提示肌动球蛋白收缩性。该项目的一个关键目标是揭示肌动球蛋白收缩性的作用 生态位形态发生和功能（目标 1）。由于生态位形态发生具有高度可重复性，该项目 还将解决将 F-肌动蛋白和 MyoII 强烈极化到利基外围的上游机制（目标 2）。 一个有趣的可能性是，贴壁的 GSC 对微环境施加的机械力会诱导细胞骨架 沿着利基边缘的极化。初步证据表明，GSC 需要进行适当的划分 生态位形态，众所周知，多种力协同作用以驱动分裂中的纺锤体伸长 细胞。该项目将解决以下假设：F-肌动蛋白和 MyoII 沿生态位外围富集是 由 GSC 纺锤体伸长诱导，对于生态位形成和功能是必需的。的组合 转基因技术将用于操纵肌动球蛋白收缩性，以及抑制微管马达 参与纺锤体伸长。该项目可能会揭示干细胞的反馈机制 塑造指导他们行为的利基，并将是最先描述塑造机制的人之一 一个功能性的利基市场。该项目的培训计划包括实验室工作、会议出席、期刊俱乐部、 实验室会议、研究生小组研讨会以及接触教学和指导角色。这项工作将是 在果蝇生物学和形态发生专家 Stephen DiNardo 博士的指导下完成， 与肌球蛋白、肌动球蛋白环形成和细胞极性方面的专家毕二飞博士共同指导。