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

• 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
• 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

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.

项目摘要 每10个孩子中，近1个在美国过早出生，尽管进步 围产期护理导致早产儿的存活率增加，其中许多孩子继续进行展览 神经发育定义导致严重的认知和运动功能障碍。最常见的 早产后的神经损伤是弥漫性白质损伤（DWMI），被认为是由 由于肺发育和脑的未成熟状态引起的发育中的大脑缺氧损伤 脉管系统，无法治愈。中枢神经系统内的沟通需要白质 主要由髓磷脂组成，髓鞘是一种脂肪鞘，周围神经元轴突可以有效作用 潜在的传播。髓磷脂是由成熟的少突胶质细胞产生的，这是通过分化而产生的 少突胶质细胞祖细胞（OPC）。在DWMI的背景下，缺氧导致细胞的细胞凋亡 少突胶质细胞谱系，然后是增生和随后的少突胶质细胞再生 剩余的OPC。在缺氧之后从OPC产生少突胶质细胞的这种赤字可以通过 淘汰缺氧引起的因子（HIF），这些因子是DNA结合转录因子，在 缺氧并在OPC中迅速降解在常氧中。但是，HIF如何阻止的机制 少突胶质细胞仍然难以捉摸。利用我们的实验室产生大型人口的能力 在OPC中，我对活性染色质标记的HIF1A和H3K27AC进行了chip-seq，以确定 推定的HIF靶向OPC基因组。基于HIF1A结合以及 H3K27AC的富集提出了一种转录因子，已证明对干细胞很重要 在中枢神经系统以外的组织中维护作为OPC中HIF的靶标。我证明了这一点 该转录因子的过表达足以抑制OPC分化为少突胶质细胞和 在DWMI小鼠模型中缺氧损伤后，被上调。该建议旨在进一步调查 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）确定下调是否下调 该转录因子将促进体外缺氧损伤后的少突胶质细胞的恢复 3）表征该转录因子在体内上调的时空动力学 DWMI的鼠标模型。该提案中概述的实验将增加我们对机制的理解 这阻碍了低氧条件下OPC从OPC产生的少突胶质细胞，并将发现新的途径 对于这种高度普遍且令人衰弱的神经发育状况的热干预。