Mechanisms of naturally-occurring astrocyte death during development

发育过程中自然发生的星形胶质细胞死亡的机制

基本信息

批准号：
9803366
负责人：
Jeremy N Kay
金额：
$ 39.54万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-30 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9803366
关键词：
Ablation Affect Anatomy Apoptosis Architecture Astrocytes Binding Binding Proteins Biology Blood Vessels Cell Count Cell Death Cell surface Cells Central Nervous System Diseases Cessation of life Childhood Complex Data Defect Development Disease Disease model Eating Excision Felis catus Genes Genetic Goals Human Hypoxia Impairment Ingestion Integrins Intervention Knowledge Learning Lipid Binding Lipids Mediating Mediator of activation protein Methods Microglia Modeling Molecular Mouse Strains Mus Neonatal Nervous system structure Neuraxis Neurons Opsonin Pathogenicity Pathologic Pathologic Neovascularization Pathology Pathway interactions Pattern Pattern Formation Phagocytes Phagocytosis Phosphatidylserines Population Public Health Research Retina Retinal Retinal Diseases Retinopathy of Prematurity Risk Factors Role Shapes Signal Transduction Stress Surface Synapses Testing Therapeutic Tissues Vascular Diseases Vision Work angiogenesis base cell type genetic manipulation hypoxia neonatorum in vivo in vivo evaluation innovation insight mouse model novel postnatal prevent receptor recruit response tegrin tool

项目摘要

ABSTRACT Naturally-occurring developmental cell death is a fundamental pattern formation mechanism in the nervous system. Whether and how cell death sculpts the astrocyte population is not known. The objective here is to gain insight into astrocyte patterning by learning the mechanisms underlying naturally-occurring astrocyte death in the mouse retina. The central hypothesis is that microglia kill and engulf retinal astrocytes in response to astrocyte-derived “eat-me” signals, thereby regulating astrocyte numbers and patterning. The rationale for this work is that retinal astrocytes dictate the pattern of developing vasculature. Knowledge of astrocyte death mechanisms will make it possible to study novel factors that shape the ultimate pattern of the astrocyte and vascular networks – in both normal and pathological developmental contexts. To this end, the following Specif- ic Aims are proposed: 1) Determine cellular mechanisms for developmental cell death of retinal astro- cytes. Preliminary studies show that retinal astrocytes are initially overproduced and then culled between postnatal days 5 and 14. These studies further suggest the working hypothesis that microglia are responsible for killing and eliminating astrocytes during this period. This will be tested in vivo using complementary anatom- ical and chemogenetic approaches. 2) Identify molecular mechanisms responsible for astrocyte elimina- tion during development. Preliminary data show that apoptosis cannot account for developmental loss of ret- inal astrocytes. Instead, a tripartite trans-cellular molecular complex – comprising phosphatidylserine on the astrocyte surface, the soluble lipid-binding protein MFGE8, and αvβ5 integrins on microglia – is implicated as a key mediator of astrocyte death. This working hypothesis will be tested using mouse genetic tools in vivo. 3) Determine contribution of developmental death to astrocyte patterning in a disease model. In both mice and humans, neonatal hypoxia exposure can perturb formation of retinal vasculature. Because astrocytes serve as a patterning template for developing vessels, astrocyte patterning defects might contribute to hypoxia- induced vascular pathology. A novel mouse model was developed to study this issue. Preliminary data from this model led to the working hypothesis that microglia-mediated astrocyte death is impaired by hypoxia, caus- ing astrocyte and vessel patterning defects. This will be tested by comparing two mouse strains: a hypoxia- sensitive strain, and a resilient strain that recovers from initial hypoxia-induced pathology. Completion of these aims is expected to: 1) provide the first mechanistic understanding of developmental astrocyte death; and 2) begin to reveal the function of death in patterning the retinal astrocyte population. This contribution will be sig- nificant because it is expected to illuminate how specific pattern formation mechanisms enable astrocyte func- tions, in the retina and throughout the nervous system. The project is innovative because it has strong potential to unveil an entirely new microglia-mediated mechanism for naturally-occurring cell death; this new mechanism may impact development of many cell types and tissues in addition to astrocytes.

抽象的自然出现的发育细胞死亡是神经的基本模式形成机制系统。尚不清楚细胞死亡是否以及如何雕刻星形胶质细胞种群。这里的目的是通过学习天然星形胶质细胞的基础机制来洞悉星形胶质细胞模式中心假设是小胶质细胞杀死和吞噬视网膜星形胶质细胞的反应为星形胶质细胞衍生的“饮食”信号，从而调节星形胶质细胞数量和图案。理由这项工作是视网膜星形胶质细胞决定了发展脉管系统的模式。星形胶质细胞死亡的知识机制将使研究塑造星形胶质细胞最终模式的新因素和血管网络 - 在正常和病理发育环境下。为此，以下指定提出了IC的目的：1）确定残留星体的发育细胞死亡的细胞机制细胞。初步研究表明，视网膜星形胶质细胞最初被过量生产，然后在产后第5天和第14天。这些研究进一步表明了小胶质细胞是负责的工作假设在此期间杀死和消除星形胶质细胞。这将使用完整的Anatom-在体内进行测试 ICAL和化学发育方法。 2）确定负责星形胶质细胞消除的分子机制在开发过程中。初步数据表明，凋亡无法解释RET的发展损失 inal星形胶质细胞。取而代之的是三方经细胞分子复合物 - 在星形胶质细胞表面，固体脂质结合蛋白MFGE8和小胶质细胞上的αVβ5整合素 - 牵涉到A作为A 星形胶质细胞死亡的关键调解人。该工作假设将在体内使用小鼠遗传工具进行测试。 3）确定发育死亡对疾病模型中星形胶质细胞模式的贡献。在两只小鼠中和人类，新生儿缺氧暴露会扰动残留脉管系统的形成。因为星形胶质细胞作为用于发展血管的图案模板，星形胶质细胞模式缺陷可能导致缺氧 - 诱导的血管病理学。开发了一种新型的鼠标模型来研究此问题。初步数据该模型导致了这样的假设，即小胶质细胞介导的星形胶质细胞死亡受到缺氧，因果关系的损害星形胶质细胞和容器模式缺陷。这将通过比较两种小鼠菌株来测试：缺氧 - 敏感性菌株和从初始缺氧诱导的病理中恢复的抗性菌株。这些完成预计目标是：1）对发育型星形胶质细胞死亡的第一个机械理解；和2）开始揭示死亡的功能，使视网膜星形胶质细胞种群模仿。这项贡献将是sig- 很重要在视网膜和整个神经系统中。该项目具有创新性，因为它具有强大的潜力揭示一种全新的小胶质细胞介导的机制，用于天然细胞死亡；这种新机制除星形胶质细胞外，还可能影响许多细胞类型和组织的发育。