Epigenetic regulation of adult neurogenesis

描述(申请人提供)：癫痫发作活动导致干细胞增殖和神经发生的深刻变化，但在癫痫诱导神经发生的机制和与癫痫的关系方面存在着根本的差距。长期目标是更好地了解在生理和病理背景下对神经细胞命运至关重要的表观遗传/转录回路。这项拨款提案的目的是阐明成年海马神经干细胞中神经发生的主要调节因子NRSF的作用。中心假设是癫痫活动触发了NRSF的失调，并选择了NRSF靶基因，介导了异常的神经发生和癫痫的发生。这项研究的基本原理是，了解癫痫等病理刺激后神经发生的机制，有可能了解脑损伤后潜在的修复反应和神经可塑性变化，并评估干细胞是否适合神经再生医学。因此，这项拟议的研究与NIH任务中与获得基础知识相关的部分相关，这些基础知识可能有助于治疗神经疾病，如癫痫。在强大的初步数据指导下，将通过追求三个特定目标来检验这一假说：1)确定负责NRSF调控神经细胞命运的表观遗传/转录机制；2)使用单细胞遗传学方法确定NRSF如何介导癫痫发作后的异常神经发生；以及3)利用NRSF条件基因敲除小鼠，确定NRSF参与癫痫诱导的神经发生和癫痫发生。AIMS 1和2将集中于NRSF在神经发生中的作用，使用功能获得和功能丧失的逆转录病毒构建体在体外和在癫痫诱导的体内神经发生过程中操纵NRSF，这与谢家华实验室的技能和经验直接相关。具体目标3将与Christopher Sinton博士合作进行，重点是使用NRSF条件基因敲除小鼠，以确定NRSF在癫痫诱导的神经发生中的作用，并检查异常神经发生对癫痫发生的贡献。这种方法是创新的，因为它有可能探索成人神经干细胞的生物学，并挖掘它们在脑损伤后细胞替代策略的潜力。这项拟议的工作意义重大，因为它有望促进和扩大我们对控制多种病理刺激后神经细胞命运的表观遗传/转录调控机制的基本理解，而不仅仅是癫痫发作。公共卫生相关性神经系统疾病、变性或创伤性损伤是美国最大的公共卫生问题之一，通常被认为是无法修复的，往往会对个人的功能能力造成灾难性的损害。然而，现在，定位于大脑特定生发中心和细胞培养中的神经干细胞的特征增加了希望，如果我们学会利用成人神经发生来临床获益，神经组织的功能性再生可能是可行的。这项研究提案将提高对神经干细胞生物学的理解，可能会导致神经系统修复和再生新药的开发。

DESCRIPTION (provided by applicant): Seizure activity induces profound changes in stem cell proliferation and neurogenesis, yet there is a fundamental gap in understanding the mechanism of seizure-induced neurogenesis and the relationship to epilepsy. The long-term goal is to better understand the epigenetic/transcriptional circuitry important for neuronal cell fate, in both physiological and pathological contexts. The objective of this grant proposal is to elucidate the role of the master regulator of neurogenesis NRSF, in adult hippocampal neural stem cells. The central hypothesis is that seizure activity triggers the dysregulation of NRSF and selects NRSF target genes that mediate aberrant neurogenesis and epileptogenesis. The rationale for the proposed research is that understanding the mechanisms of neurogenesis after pathologic stimuli, such as seizures, has the potential to understand the underlying repair response and neuroplasticity changes after brain injury, and evaluate the suitability of stem cells for neuro-regenerative medicine. Thus, the proposed study is relevant to that part of NIH's mission that relates to gaining fundamental knowledge that will potentially help treat neurological disorders, such as epilepsy. Guided by strong preliminary data, this hypothesis will be tested by pursuing three specific aims: 1) Identify the epigenetic/transcriptional mechanism that is responsible for NRSF regulation of neuronal cell fate; 2) Determine how NRSF mediates aberrant neurogenesis after seizures using a single-cell genetic approach, and 3) Establish that NRSF contributes to seizure-induced neurogenesis and epileptogenesis using NRSF conditional knockout mice. Aims 1 and 2 will focus on the role of NRSF in neurogenesis, using gain-of-function and loss-of-function retroviral constructs to manipulate NRSF in vitro and during seizure-induced neurogenesis in vivo, which directly relate to the skills and experience in the Hsieh lab. Specific Aim 3 will be performed in collaboration with Dr. Christopher Sinton, and focus on the use of the NRSF conditional knockout mouse, to determine the role of NRSF in seizure-induced neurogenesis, and examine the contribution of aberrant neurogenesis to epileptogenesis. The approach is innovative, because it has the potential to explore the biology of adult neural stem cells and tap into their potential for cell replacement strategies after brain injury. The proposed work is significant, because it is expected to advance and expand our basic understanding of epigenetic/transcriptional regulatory mechanisms controlling neuronal cell fate after a wide range of pathologic stimuli, not just seizures. PUBLIC HEALTH RELEVANCE Disease, degeneration or traumatic injury of the nervous system are among the greatest public health concerns in the United States and are generally considered irreparable, often causing catastrophic damage to the functional capacity of the individual. Now, however, characterization of neural stem cells residing within specific germinal centers of the brain and in cell culture raises hope that functional regeneration of nervous tissue may be feasible, if we learn to exploit adult neurogenesis for clinical benefit. The research proposal will lead to improved understanding of neural stem cell biology, possibly leading to the development of new drugs for repair and regeneration of the nervous system.