Morphogenesis and function of somatosensory axon ensheathment by epidermal cells

表皮细胞体感轴突鞘的形态发生和功能

基本信息

批准号：
10220849
负责人：
Alvaro Sagasti
金额：
$ 35.61万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-05-15 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10220849
关键词：
Adherens Junction Adult Affect Afferent Neurons Animals Axon Basal Cell Behavioral Assay CRISPR screen CRISPR/Cas technology Caenorhabditis elegans Cell membrane Cell physiology Cells Chemicals Cholesterol Complement Dendrites Desmosomes Development Disease Drosophila genus Epidermis Epithelial Epithelial Cells Event F-Actin Fishes Functional disorder Grant Human Image Individual Integral Membrane Protein Larva Lipids Mammals Mechanics Mediating Membrane Methods Microscopy Modeling Molecular Morphogenesis Mutagenesis Neck Nervous System Physiology Neurites Neuroglia Neurons Neurophysiology - biologic function Nociception Pain Periderm Peripheral Play Process Property Proteins Reporter Resolution Role Schwann Cells Sensory Signal Transduction Site Skin Stimulus Structure Study models Subcellular structure Supporting Cell System Testing Touch sensation Transgenic Organisms Vertebrates Work Zebrafish cell type epidermis cell experimental study fly innovation keratinocyte knock-down neural circuit neuron development optogenetics pain sensation plakoglobin protein distribution receptor recruit repaired response seal sensor somatosensory temporal measurement tool transcriptome virtual

项目摘要

PROJECT SUMMARY Selective interactions between neurons and non-neuronal cells are crucial for the development and function of neural circuits. Pain-sensing somatosensory neurons project peripheral axons to the skin, where they branch extensively amongst epithelial epidermal cells. Although these sensory terminals are called “free endings”, recent studies have revealed that they are often wrapped by epidermal cells, which enclose them into ensheathment channels reminiscent of those formed by non-myelinating Remak Schwann cells. Although underappreciated, epidermal ensheathment channels have been observed in worms, flies, fish, and mammals, indicating that ensheathment is a conserved feature of epidermal sensory endings, and thus likely plays critical roles in the development and function of nociceptive axons. Little is known about the morphogenetic process of axon ensheathment by epidermal cells, and nothing is known about how these structures contribute to sensory function or disease in vertebrate animals. This proposal investigates the morphogenetic mechanisms that create epidermal ensheathment channels and how they contribute to sensory function in zebrafish larvae. Their external development and the availability of unique transgenic tools make zebrafish an ideal model for studying this dynamic morphogenetic process. Preliminary work using live fluorescent reporters for subcellular structures in zebrafish skin cells identified a sequence of events leading up to ensheathment and suggested a step-wise morphogenetic process. First, axons growing into this epidermis induce the formation of specialized lipid microdomains at skin cell-axon contact sites. Second, F-actin is recruited to these microdomains, likely promoting membrane invagination to initiate the ensheathment process. Finally, adherens junctions and desmosomes form at “necks” of ensheathment channels to tightly seal the channels. The first two aims of this proposal use innovative microscopy approaches for high spatial and temporal resolution live imaging, cell-specific molecular manipulations, and CRISPR/Cas9-mediated mutagenesis to determine how axons and skin cells establish selective interactions and execute the ensheathment process. These studies will illuminate morphogenetic mechanisms relevant not just to axon ensheathment by epidermal and glial cells, but also to basic cellular processes, like the formation of membrane signaling domains and junction assembly. The third aim combines imaging and behavioral assays to reveal how axon ensheathment impacts neuronal structure and function. These studies have the potential to uncover a critical feature of the touch-sensing apparatus and suggest how ensheathment contributes to disease conditions affecting pain and touch sensation.

项目摘要神经元与非神经元细胞之间的选择性相互作用对于发展和功能至关重要神经回路。疼痛感应的体感神经元向皮肤分支的外周轴突在上皮表皮细胞中广泛。尽管这些感觉终端称为“自由结局”，但最近的研究表明，它们通常被表皮细胞包裹，将它们包围成包容通道让人联想到非层状remak schwann细胞形成的通道。虽然在蠕虫，苍蝇，鱼类和哺乳动物中都观察到了未充分认识的表皮宿内通道表明包容是表皮感觉结局的保守特征，因此可能发挥着关键的作用在伤害感受轴突的发展和功能中的作用。关于形态发生过程知之甚少表皮细胞的轴突包裹，这些结构如何有助于感觉脊椎动物的功能或疾病。该提案调查了形态发生机制，这些机制产生了表皮宿内通道和它们如何促进斑马鱼幼虫中的感觉功能。他们的外部发展和可用性独特的转基因工具使斑马鱼成为研究这种动态形态学过程的理想模型。使用实时荧光记者进行斑马鱼皮细胞中亚细胞结构的初步工作确定导致出发事件的事件序列，并提出了逐步形态发生过程。第一的，轴突生长到该表皮中会诱导皮肤细胞轴的专用脂质微域的形成联系站点。其次，将F-肌动蛋白募集到这些微域中，可能会促进膜的起伏启动召唤过程。最后，在“颈部”形成的粘附连接体和脱骨体形成设备通道以紧密密封通道。该提案的前两个目标使用创新高空间和临时分辨率的显微镜方法实时成像，细胞特异性分子操纵以及CRISPR/CAS9介导的诱变，以确定轴突和皮肤细胞的建立方式选择性互动并执行设备过程。这些研究将阐明形态学不仅与表皮和神经胶质细胞的轴突套装相关的机制，还与基本的细胞相关过程，例如形成膜信号域和连接组件。第三个目标结合了成像和行为测定，以揭示轴突宿内如何影响神经元结构和功能。这些研究有可能发现接触式设备的关键特征，并提出如何宿舍有助于影响疼痛和触摸感的疾病状况。