Transpositional scaling and niche transitions restore organ size and shape during zebrafish fin regeneration

斑马鱼鳍再生过程中，转位缩放和生态位转变可恢复器官大小和形状

基本信息

批准号：
10115761
负责人：
KRYN STANKUNAS
金额：
$ 41.45万
依托单位：
UNIVERSITY OF OREGON
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-08 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10115761
关键词：
Adult Alleles Anatomy Animals Bone Diseases Bone Regeneration CRISPR/Cas technology Cell Lineage Cells Code Complex Congenital Abnormality Distal Dorsal Ectopic Expression Epigenetic Process Epithelial Family Gene Expression Profile Gene Expression Profiling Genetic Genetic Transcription Geometry Growth Health Homeostasis Human Individual Injury Instruction Ion Channel Lead Long QT Syndrome Malignant Neoplasms Mesenchymal Mesenchyme Modeling Molecular Mosaicism Mutate Mutation Natural regeneration Nature Organ Organ Size Phenotype Population Positioning Attribute Potassium Channel Process Production Property Proteins Regenerative Medicine Research Resolution Scientist Shapes Signal Transduction Site Skeleton Specific qualifier value System Testing Tissues Translating WNT Signaling Pathway Width Work Zebrafish bone bone geometry cell type exhaust experimental study fundamental research human disease insight novel organ regeneration predictive modeling progenitor programs repaired research study self-renewal single-cell RNA sequencing skeletal regeneration small molecule stem cells technological innovation therapeutic target tissue repair transcription factor tumor

项目摘要

PROJECT SUMMARY: Organs and other complex tissues “know” when and how to stop growing to arrive at the correct size and shape. Disruption of organ size control mechanisms can lead to congenital abnormalities, poor organ homeostasis and tissue repair, and tumors. Adult zebrafish caudal fins, including their complex skeleton and other tissues, perfectly regenerate to their original size and shape regardless of the nature or position of the injury. Therefore, zebrafish fin regeneration provides a compelling and genetically tractable vertebrate model to interrogate organ size control mechanisms. Prevailing models for robust fin size regeneration speculate that fin cells maintain a multitude of “positional identities” that somehow instruct different degrees of outgrowth. We propose a distinct and straightforward model that neatly explains how fin size and shape is restored without invoking molecularly encoded positional information. A key cell population at the distal end of the regenerating fin that we term the “niche” produces Wnt signals that promote fin outgrowth by sustaining progenitor cells. We identify Dachsund transcription factors as novel niche markers and show that the niche uniquely forms from intra-‐‑ray mesenchyme that populates the inside of the cylindrical, differentially sized, and progressively tapered fin rays. We show that the niche, and therefore Wnt, steadily dissipates as regeneration unfolds; once exhausted, growth stops. As such, regenerated fin size is dictated by the amount of niche formed upon damage – which is simply dependent on the availability of intra-‐‑ray mesenchyme and hence bone width at the damage site. This “transpositional scaling” model suggests that macro-‐‑scale fin size and shape is determined by mesenchyme-‐‑niche state transitions and self-‐‑restoring bone geometry rather than unique positional identities of individual cells. We will explore this paradigm and uncover underlying cell and molecular mechanisms for size control during fin regeneration by three Specific Aims: 1. Define intra-‐‑ray mesenchyme / distal niche lineage cell states, transitions, and fates, 2. Determine signaling and transcriptional mechanisms maintaining niche state and function, and 3. Determine niche “countdown timer” mechanisms using longfint2 zebrafish – which we show have a broken timer due to misexpression of the kcnh2a ion channel. This insight suggests ion channels and Ca2+ signaling govern niche cell self-‐‑renewal. Our program will support a potentially broadly applicable “transpositional scaling” concept with exemplary mechanisms for how organ size and shape are determined by dynamic populations of tissue-‐‑resident niche cells. Our study will have additional human health impacts since 1) understanding bone regeneration in zebrafish may inform regenerative medicine approaches for human bone disease, and 2) kcnh2a is the zebrafish orthologue of kcnh2, which is commonly mutated in long QT syndrome and encodes a protein that is a notorious therapeutic “off-‐‑ target”. Our paradigmatic and diverse technological innovations will open up new directions and inspire other scientists, broadening our project’s impact on both fundamental research and regenerative medicine.

项目概要：器官和其他复杂组织“知道”何时以及如何停止生长以达到正确的大小和器官大小控制机制的破坏可能导致先天性畸形、器官不良。稳态和组织修复，以及成年斑马鱼尾鳍，包括其复杂的骨骼和肿瘤。其他组织，无论其性质或位置如何，都能完美地再生为其原始大小和形状因此，斑马鱼鳍再生提供了一个引人注目的、遗传上易于处理的脊椎动物模型。为了探究器官尺寸控制机制，目前流行的鳍尺寸再生模型推测：鳍细胞维持着多种“位置特征”，以某种方式指示不同程度的生长。我们提出了一个独特而直接的模型，它巧妙地解释了如何在不发生任何情况下恢复鳍的尺寸和形状。调用分子编码的位置信息。我们称之为“生态位”的鳍再生产生 Wnt 信号，通过维持我们将腊肠犬转录因子鉴定为新的生态位标记，并表明该生态位独特地由射线内间充质形成，填充在圆柱形内部，大小不同，我们表明，生态位以及 Wnt 逐渐消散。再生开始；一旦耗尽，生长就会停止，因此，再生的鳍大小取决于再生的数量。损伤后形成——这只是一个生态位，取决于射线间质的可用性和因此，这种“换位缩放”模型表明，宏观尺度的鳍尺寸。形状是由间质——生态位状态转变和自恢复骨几何形状决定的，而不是由我们将探索这个范式并揭示潜在的细胞和个体细胞的独特位置身份。通过三个具体目标来确定鳍再生过程中尺寸控制的分子机制： 1. 定义内射线间质/远端生态位谱系细胞状态、转变和命运，2. 确定信号传导和转录维持利基状态和功能的机制，以及 3. 确定利基“倒计时器”机制使用 longfint2 斑马鱼——我们发现由于 kcnh2a 离子通道的错误表达，它的计时器出现故障。这一见解表明离子通道和 Ca2+ 信号传导控制微环境细胞的自我更新。我们的计划将支持这一点。一个潜在广泛适用的“换位缩放”概念，具有器官如何发挥作用的示范机制大小和形状由组织驻留细胞的动态群体决定。我们的研究将有其他人类健康影响，因为 1) 了解斑马鱼的骨再生可能会提供信息人类骨骼疾病的再生医学方法，2) kcnh2a 是 kcnh2 的斑马鱼直系同源物，它通常在长 QT 综合征中发生突变，并编码一种臭名昭著的治疗“off--- 我们的范式和多样化的技术创新将开辟新的方向并激励其他人。科学家，扩大我们的项目对基础研究和再生医学的影响。