Interrogation and Modulation of the Epigenome after Prenatal Hypoxic Brain Injury

项目摘要 新生儿缺氧缺血性脑病（HIE）是一种常见的缺氧性脑损伤， 营养素，导致长期的神经功能缺损，即使在没有显着的 围产期细胞死亡在围产期损伤领域的一个主要差距是有限的机械理解如何 短暂的缺氧导致持续的细胞缺陷。一个令人信服的机制将产前缺氧与 持续性缺陷是产前缺氧永久性地改变表观基因组，因为表观基因组整合 发展与环境相适应。 为了研究缺氧缺血性脑病的病理机制，我开发了一种新的小鼠模型， 妊娠晚期产前缺氧损伤表现为轻度HIE。产前缺氧导致持续的行为 和结构缺陷，尽管胎儿脑中的细胞死亡没有显著增加。我的初步 出生后28天（P28），24周（P28），皮质丘脑神经元树突棘密度降低， 缺氧后。产前缺氧与表观基因组相关基因的上调有关， 胎儿单核RNA和用于转座酶可及染色质测序（snRNA/ATAC-seq）的测定 一小时后的大脑皮层上调最多的基因之一，组蛋白变体H3 f3 b，是一种 保护大脑免受更严重的脑损伤的候选人。然而， 皮质丘脑神经元似乎甚至在缺氧暴露后立即移位。因此，我的中央 假设H3 f3 b上调对于保护神经元免受严重损伤是必要且充分的 出生前缺氧后，不同的表观遗传调节因子有助于持久的神经元损伤。 为了验证我的假设，我提出了三个目标。在目标1中，我将使用条件性敲除小鼠来测试H3 f3 b是否 耗尽增加细胞缺氧后立即死亡，并使脊髓棘密度的持续缺陷消失， P28小鼠和成年小鼠的行为。在目标2中，我将使用子宫内电穿孔来测试是否过度表达 H3 f3 b改善了P28小鼠脊柱密度和成年小鼠行为的缺氧缺陷。最后，在目标3中， 我建议在P28小鼠的皮质中使用snRNA/ATAC-seq，以确定产前缺氧是否具有永久性的遗传毒性。 对皮质丘脑神经元表观基因组的影响。 我的长期目标是成为一名儿童神经学家，利用我在分子生物学方面的研究专长， 以及围产期脑损伤方面的临床技能， 损伤我的导师，埃里克·马什博士和迈克尔·埃洛维茨博士，都是优秀的内科科学家，致力于使用 转化研究，以改善儿童神经系统疾病的结果。在他们的指导下， 这个K 08的建议，我将获得额外的技能，在生物信息学，在转化动物研究更深入的专业知识， 和实验室管理技能，成为神经系统疾病的表观遗传学专家， 准备作为一个独立的R 01资助的医生科学家的职业生涯。

PROJECT SUMMARY Neonatal hypoxic ischemic encephalopathy (HIE), a common brain injury from loss of oxygen and nutrients immediately prior to birth, results in long-term neurologic deficits even in the absence of significant perinatal cell death. A major gap in the perinatal injury field is the limited mechanistic understanding of how transient hypoxia results in persistent cellular deficits. A compelling mechanism linking prenatal hypoxia to persistent deficits is that prenatal hypoxia permanently alters the epigenome because the epigenome integrates development with response to the environment. To study the mechanisms underlying the pathology of HIE, I developed a novel mouse model of transient late gestation prenatal hypoxic injury that phenocopies mild HIE. Prenatal hypoxia leads to persistent behavioral and structural deficits in adult mice despite no significant increase in cell death in the fetal brain. My preliminary data showed decrease in dendritic spine density in corticothalamic neurons at postnatal day 28 (P28), weeks after hypoxia. Prenatal hypoxia was associated with upregulation of genes associated with the epigenome in single nucleus RNA and assay for transposase-accessible chromatin sequencing (snRNA/ATAC-seq) in the fetal neocortex within one hour of exposure. One of the most upregulated genes, the histone variant H3f3b, is a candidate for protecting the brain from more severe brain injury. However, the epigenetic trajectories of corticothalamic neurons seemed to be shifted even immediately after hypoxic exposure. Therefore, my central hypothesis is that H3f3b upregulation is necessary and sufficient to protect neurons from severe injury after prenatal hypoxia and distinct epigenetic regulators contribute to lasting neuronal injury. To test my hypothesis, I propose three aims. In Aim 1, I will use conditional knockout mice to test if H3f3b depletion increases cell death immediately after hypoxia and worsens the persistent deficits in spine density in P28 mice and behaviors in adult mice. In Aim 2, I will use in utero electroporation to test if overexpression of H3f3b improves deficits from hypoxia in spine density in P28 mice and behaviors in adult mice. Lastly, in Aim 3, I propose to use snRNA/ATAC-seq in the cortex of P28 mice to determine if prenatal hypoxia has a permanent effect on the epigenome of corticothalamic neurons. My long-term goal is to be a child neurologist who leverages my research expertise in molecular biology and clinical skills in perinatal brain injury both to develop targeted therapies towards this frequently devastating injury. My mentors, Drs. Eric Marsh and Michal Elovitz, are excellent physician scientists devoted to using translational research to improving outcomes in children with neurological disorders. Under their guidance for this K08 proposal, I will gain additional skills in bioinformatics, a deeper expertise in translational animal studies, and lab management skills necessary to become an expert in the epigenetics of neurological disorders and be prepared for a career as an independent R01-funded physician scientist.