Mechanism of hypoxia mediated failure of oligodendrocyte generation

缺氧介导少突胶质细胞生成失败的机制

基本信息

批准号：
10453705
负责人：
Kevin Cameron Allan
金额：
$ 1.29万
依托单位：
CASE WESTERN RESERVE 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：
2019-07-01 至 2022-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10453705
关键词：
ASCL2 gene Action Potentials Adult Affect Animal Model Apoptosis Axon BHLH Protein Binding Biological Assay Brain Cell Differentiation process Cell Maintenance Cells Cerebrovascular system ChIP-seq Child Chromatin Chronic Clustered Regularly Interspaced Short Palindromic Repeats Cognitive deficits Communication DNA Binding Data Defect Development Diffuse Disease Down-Regulation E-Box Elements Enhancers Exhibits Failure Family Future Gene Targeting Generations Genes Genetic Techniques Genome Hypoxia Hypoxia Inducible Factor Immunohistochemistry Impaired cognition In Vitro Infant Injury Knock-out Lesion Luciferases Maintenance Mediating Modeling Molecular Genetics Mus Myelin Natural regeneration Neuraxis Neurodevelopmental Deficit Neurodevelopmental Disorder Neurologic Neurons Oligodendroglia Perinatal Care Pluripotent Stem Cells Population Premature Birth Premature Infant Recovery Residual state Role Small Interfering RNA Testing Therapeutic Intervention Tissues United States Up-Regulation Western Blotting base blocking factor brain tissue cell type experimental study genetic technology in vitro Model in vivo insight knock-down lung development motor deficit motor disorder mouse model new technology normoxia novel oligodendrocyte lineage oligodendrocyte progenitor overexpression premature prevent promoter pup restoration spatiotemporal stem cells transcription factor white matter white matter injury

项目摘要

PROJECT SUMMARY Nearly 1 out of every 10 children are born prematurely in the United States and although advancements in perinatal care have resulted in the increased survival of preterm infants, many of these children go on to exhibit neurodevelopmental deficits leading to significant cognitive and motor dysfunction. One of the most common neurologic insults following preterm birth is diffuse white matter injury (DWMI), which is thought to arise from hypoxic injury to the developing brain caused by the immature state of lung development and cerebral vasculature and has no cure. White matter is required for communication within the central nervous system and is primarily composed of myelin, which is a fatty sheath that surrounds neuronal axons to allow efficient action potential propagation. Myelin is generated by mature oligodendrocytes, which arise via differentiation of oligodendrocyte progenitor cells (OPCs). In the context of DWMI, hypoxia leads to apoptosis of cells of the oligodendrocyte lineage followed by proliferation and failure of subsequent oligodendrocyte regeneration from residual OPCs. This deficit in oligodendrocyte generation from OPCs following hypoxia can be abrogated by knocking out hypoxia inducible factors (HIFs), which are DNA-binding transcription factors that accumulate under hypoxia and are rapidly degraded in normoxia, in OPCs. However, the mechanism of how HIFs block oligodendrocyte generation remains elusive. Leveraging our lab’s ability to generate large and pure populations of OPCs, I performed ChIP-seq for HIF1a and H3K27Ac, a marker of active chromatin, in order to determine putative HIF targets across the OPC genome. The top candidate target based on HIF1a binding as well as enrichment of H3K27Ac suggested a transcription factor that has been shown to be important for stem cell maintenance in tissues outside the central nervous system as a target of HIF in OPCs. I demonstrate that overexpression of this transcription factor is sufficient to inhibit differentiation of OPCs to oligodendrocytes and is upregulated following hypoxic injury in a mouse model of DWMI. This proposal seeks to further investigate these findings by 1) utilizing a combination of cellular, molecular and genetic techniques to determine the mechanism by which this transcription factor inhibits OPC differentiation 2) determining whether downregulation of this transcription factor will facilitate recovery of oligodendrocyte formation following hypoxic injury in vitro and 3) characterizing the spatiotemporal dynamics of the upregulation of this transcription factor in vivo using a mouse model of DWMI. The experiments outlined in this proposal will increase our understanding of mechanisms that impede oligodendrocyte generation from OPCs under hypoxic conditions, and will uncover novel avenues for therapeutic intervention for this highly prevalent and debilitating neurodevelopmental condition.

项目概要在美国，近十分之一的儿童早产，尽管在这方面取得了进步围产期护理提高了早产儿的存活率，其中许多儿童继续表现出神经发育缺陷导致严重的认知和运动功能障碍。早产后的神经损伤是弥漫性白质损伤（DWMI），被认为是由肺和脑发育不成熟导致发育中的大脑缺氧损伤脉管系统并且无法治愈。白质是中枢神经系统内沟通所必需的。主要由髓磷脂组成，髓磷脂是围绕神经元轴突的脂肪鞘，可实现有效的作用髓鞘质由成熟的少突胶质细胞产生，通过分化产生。在 DWMI 的情况下，缺氧会导致少突胶质细胞祖细胞 (OPC) 细胞凋亡。少突胶质细胞谱系随后增殖并随后少突胶质细胞再生失败缺氧后 OPC 生成少突胶质细胞的这种缺陷可以通过以下方法消除：敲除缺氧诱导因子 (HIF)，这是在缺氧条件下积累的 DNA 结合转录因子 OPCs 在缺氧条件下会迅速降解，但 HIF 的阻断机制尚不清楚。少突胶质细胞的产生仍然难以捉摸，利用我们实验室产生大量纯群体的能力。 OPCs，我对 HIF1a 和 H3K27Ac（活性染色质标记）进行了 ChIP-seq，以确定跨 OPC 基因组的假定 HIF 靶点基于 HIF1a 结合以及的最佳候选靶点。 H3K27Ac 的富集表明转录因子已被证明对干细胞很重要我证明，作为 OPC 中 HIF 的靶标，可以维持中枢神经系统以外的组织。该转录因子的过度表达足以抑制 OPC 向少突胶质细胞的分化在 DWMI 小鼠模型中缺氧损伤后表达上调该提案旨在进一步研究。这些发现通过 1) 利用细胞、分子和遗传技术的组合来确定该转录因子抑制 OPC 分化的机制 2) 确定是否下调该转录因子的作用将促进体外缺氧损伤后少突胶质细胞形成的恢复 3）使用体内转录因子上调的时空动态特征本提案中概述的实验将增加我们对 DWMI 机制的理解。阻碍低氧条件下 OPC 产生少突胶质细胞，并将揭示新的途径对这种高度普遍且使人衰弱的神经发育状况进行治疗干预。