Dynamic regulatory mechanisms of robust pattern formation in the neural tube

神经管中稳健模式形成的动态调节机制

基本信息

批准号：
9199417
负责人：
SEAN G MEGASON
金额：
$ 31.57万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-04-13 至 2019-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9199417
关键词：
Address Adopted Alpha Cell Biomedical Engineering Biophysical Process Buffers Cadherins Cell Adhesion Molecules Cell Proliferation Cell Separation Cells Color Complex Congenital Abnormality Data Decision Making Development Developmental Biology Diagnosis Diffusion Disease Dorsal Dysmorphology Embryo Ensure Evolution Face Feedback Gene Expression Gene Targeting Genetic Goals Image Image Analysis Knowledge Location Measures Mechanics Methodology Microfluidics Microscopy Modeling Molecular Monitor Morphogenesis Morphology Mosaicism Motor Neurons Network-based Neural Tube Defects Neural tube Noise Organ Organism Pattern Pattern Formation Phenotype Physiologic pulse Positioning Attribute Process Publishing Refractory Regulator Genes Research Resolution SHH gene Shapes Sigmoid colon Signal Transduction Signaling Molecule Sorting - Cell Movement Source Specific qualifier value Spinal Cord System Testing Time Tissue Engineering Tissues Variant Work Zebrafish base biophysical properties cell fate specification cell type design engineering design experimental study in vivo insight intercalation interfacial knock-down mathematical model morphogens nerve stem cell neural patterning neural plate novel strategies overexpression prevent progenitor public health relevance quantitative imaging response smoothened signaling pathway transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of our research is to understand the principles that permit developmental systems to robustly construct embryos of the correct pattern, shape, and size. Developmental systems face a gamut of variations from different sources including environmental, genetic, and stochastic, which manifest at multiple levels from molecules to cells to organs. In the face of these challenges, organisms have been designed through evolution to buffer the phenotype against these variations in order to robustly achieve a developmental norm, a process Waddington termed canalization. As our knowledge of the molecular and cellular details of patterning systems has expanded, there is now the opportunity to understand the systems level mechanisms that give rise to robust pattern formation. Here we focus on dorsal-ventral patterning of the neural tube where it is thought that a smooth and steady gradient of the signaling molecule Sonic Hedgehog acts as a morphogen to precisely specify different domains of neural progenitors at defined positions as a function of concentration. Using a novel approach developed in my lab called in Toto imaging in zebrafish, we have discovered that in reality both the morphogen source and response are noisy and dynamically changing as cells make fate decisions. We have found that this noisy and dynamic morphogen results in specification of fate-restricted progenitors in a mixed and overlapping pattern. Directional sorting of specified cells then corrects these positional errors resulting in sharply defined domains. Remarkably, forced specification of motor neuron progenitors at ectopic locations causes these cells to move to the motor neuron progenitor (pMN) domain and replace the would be pMN cells resulting in a normally patterned and viable embryo formed from a very different developmental trajectory. Here we seek to elucidate the mechanisms underlying this robustness. Using a combination of quantitative time-lapse imaging, precise genetic perturbations, biophysical measurements, and modeling, we will: 1) Decode how a large diversity of temporally increasing Shh signals are processed to give rise to a small set of discrete cell fates; 2) Determine the mechanism of cell sorting in zebrafish neural tube patterning. Together our work should help explain how molecular and cellular mechanisms interact at multiple steps to ensure precise pattern formation. Such an integrated understanding is important for diagnosing and treating birth defects such as neural tube defects and in the rational design of engineered tissues.

描述（由适用提供）：我们研究的长期目标是了解允许开发系统可靠地构建正确模式，形状和大小的胚胎的原理。发展系统面临着来自不同来源在内的各种差异，包括环境，遗传和随机性，它们在从分子到细胞再到器官的多个水平都表现出来。面对这些挑战，已经通过进化设计了生物体，以缓冲表型，以防止这些变化，以便于实现发展规范，这是Waddington的过程称为流动的过程。随着我们对模式系统的分子和细胞细节的了解，现在有机会了解产生强大模式形成的系统级机制。在这里，我们专注于神经管的背腹模式，其中认为，信号分子声音刺猬的平稳而稳定的梯度充当形态学，可以精确指定在定义位置的不同域的不同结构域作为浓度的函数。使用我的实验室中开发的一种新方法，称为斑马鱼中的Toto成像，我们发现实际上，形态源和反应都是噪音，并且随着细胞做出命运决定而动态变化。我们发现，这种噪声和动态形态学导致在混合和重叠模式下对命运限制的祖细胞的规定。然后，指定单元格的定向分选会纠正这些位置误差，从而导致明确定义的域。值得注意的是，在回声位置的运动神经元祖细胞的强迫指定导致这些细胞移动到运动神经元祖细胞（PMN）结构域并取代将是PMN细胞，从而导致正常形成且可行的胚胎是由非常不同的发育轨迹形成的。在这里，我们试图阐明这种鲁棒性的基础机制。使用定量的延时成像，精确的遗传扰动，生物物理测量和建模的组合，我们将：1）解释如何处理大量暂时增加SHH信号以产生一小部分离散细胞命运； 2）确定斑马鱼神经管模式中细胞分选的机理。我们的工作应有助于解释分子和细胞机制如何在多个步骤中相互作用，以确保精确的模式形成。这种综合理解对于诊断和治疗先天缺陷，例如神经管缺陷以及工程组织的合理设计很重要。