Chromatin-based regulation of neural stem cells

基于染色质的神经干细胞调控

• 批准号: 9898212
• 负责人: DANIEL A LIM
• 金额: --
• 依托单位: VETERANS AFFAIRS MED CTR SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9898212
• 关键词: Adult; Award; Bioinformatics; Biology; Brain; Cell Transplantation; Cell division; Cells; Cellular biology; Chemicals; Chromatin; Chromatin Structure; Collaborations; DNA; Data; Development; Dorsal; Embryo; Epigenetic Process; Gene Expression; Genes; Genetic Enhancer Element; Genetic Transcription; Genomics; Goals; Homeobox; Human; In Vitro; Intellectual functioning disability; Knowledge; MLL gene; Maintenance; Memory; Methods; Mixed-Lineage Leukemia; Molecular; Mutation; Neuroglia; Neurons; Parkinson Disease; Pattern; Play; Population; Production; Proteins; Publishing; Regulatory Element; Role; SHH gene; Source; Syndrome; System; Testing; Therapeutic; Translational Research; Transplantation; Traumatic Brain Injury; Ventricular; Veterans; Work; autism spectrum disorder; base; cell type; conditional knockout; daughter cell; developmental disease; drug development; drug discovery; human stem cells; in vivo; inhibitor/antagonist; innovation; insight; interest; morphogens; nerve stem cell; nervous system disorder; neurodevelopment; neurogenesis; neuroregulation; novel therapeutics; postnatal; programs; relating to nervous system; smoothened signaling pathway; stem cell biology; stem cell differentiation; stem cell population; subventricular zone; transcription factor; transcriptome

Neural stem cells (NSCs) hold promise for the treatment of a wide range of neurological disorders common to Veterans such as traumatic brain injury (TBI) and Parkinson's disease. In addition to providing cells for transplantation-based therapies, NSCs are also an important source of human neurons and glia for drug discovery and development. To realize the full potential of NSCs for human therapy, it is important to understand the molecular mechanisms that regulate the production of specific neural cell types. Our long-term goal is to understand the cellular and molecular mechanisms by which NSCs produce specific types of neurons and glia. The postnatal and adult mammalian brain harbors NSCs in the ventricular-subventricular zone (V- SVZ). Importantly, V-SVZ NSCs retain distinct regional identities that underlie the production of different neuronal subtypes. For instance, NSCs in the ventral V-SVZ produce neuron subtypes different from those born from NSCs in the dorsal V-SVZ. Furthermore, such NSC regional identity is largely cell-intrinsic, and we have shown that NSCs “remember” their regional identity through serial cell divisions. The expression of Nkx2.1 defines a population of NSCs in the ventral V-SVZ. While sonic hedgehog (SHH) is required to induce Nkx2.1 expression in ventral NSCs of the early embryonic brain, our Preliminary Studies indicate that SHH- signaling is not required for the maintenance of Nkx2.1 expression in ventral V-SVZ NSCs, suggesting that these cells epigenetically “remember” their regional identity. Mixed lineage leukemia-1 (Mll1) encodes a chromatin regulator that is part of an evolutionarily conserved transcriptional memory system, and MLL1 is required for normal V-SVZ neurogenesis. We found MLL1 protein enriched at Nkx2.1 regulatory elements, and disruption of MLL1 activity with either conditional Mll1 deletion or an MLL1-specific chemical inhibitor resulted in the loss of Nkx2.1 expression in ventral V-SVZ NSCs. After reversal of MLL1 inhibition, Nkx2.1 expression remained low, but neuronal production was restored. Based on these findings, our central hypothesis is that MLL1 is required to maintain NSC regional identity via specific chromatin state changes. In this renewal application, we propose to investigate the role of MLL1 in NSC regional identity and determine the molecular mechanisms by which MLL1 maintains region-specific gene expression. Given that NSC regional identity is a critical aspect of their neurogenic potential, results obtained will have important implications for our ability to produce specific types of neurons for human translational research and transplantation therapies. Furthermore, these studies advance new basic, neurodevelopmental concepts regarding NSC regional identity, which may be important to understanding how mutations in human MLL1 cause Weidemann-Steiner Syndrome, a developmental disorder that includes intellectual disability and autism. Finally, discovering MLL1-dependent mechanisms at genomic regulatory elements will likely be of interest to the broader fields of neurodevelopment, epigenetics and stem cell biology. Our Preliminary Studies, expertise in V-SVZ and chromatin biology, and our productive collaborations with Dr. Aaron Diaz (for bioinformatics innovation and support), support the feasibility of this project.

神经干细胞（NSC）有望治疗多种神经系统疾病 诸如脑外伤（TBI）和帕金森氏病等退伍军人共同。除了提供 基于移植的疗法的细胞，NSC也是人类神经元和神经胶质的重要来源 药物发现与发育。要实现NSC对人类治疗的全部潜力，重要的是 了解调节特定神经细胞类型的产生的分子机制。我们的长期 目标是了解NSC产生特定类型神经元的细胞和分子机制 和神经胶质。产后和成年哺乳动物脑在心室 - 腔内区域内拥有NSC（V- SVZ）。重要的是，V-SVZ NSC保留了不同的区域身份，这些身份是不同的。 神经元亚型。例如，腹V-SVZ中的NSC产生的神经元亚型不同于 来自NSC的背面V-SVZ。此外，这种NSC区域身份在很大程度上是细胞中的，我们 已经表明，NSC通过串行细胞分裂“记住”其区域身份。表达 NKX2.1定义了腹侧V-SVZ中的NSC人群。而Sonic刺猬（SHH）需要诱导 NKX2.1早期胚胎大脑腹侧NSC中的表达，我们的初步研究表明SHH- 在腹侧V-SVZ NSC中维持NKX2.1表达不需要信号传导，这表明 这些细胞表观遗传“记住”其区域身份。混合谱系白血病1（MLL1）编码A 染色质调节剂是进化配置的转录存储系统的一部分，MLL1为 正常V-SVZ神经发生所需。我们发现在NKX2.1调节元件上富含MLL1蛋白，并且 导致有条件MLL1缺失或MLL1特异性化学抑制剂的MLL1活性的破坏。 在腹侧V-SVZ NSC中NKX2.1表达的丧失中。 MLL1抑制反转后，NKX2.1表达 仍然很低，但神经元产生恢复。基于这些发现，我们的中心假设是 需要MLL1通过特定的染色质状态变化维持NSC区域身份。在此续约中 应用，我们建议研究MLL1在NSC区域身份中的作用并确定分子 MLL1维持区域特异性基因表达的机制。鉴于NSC区域身份是 其神经源潜力的关键方面，获得的结果将对我们的能力具有重要意义 产生特定类型的神经元用于人类翻译研究和移植疗法。此外， 这些研究推进了有关NSC区域身份的新的基本神经发育概念，这可能 了解人Mll1中的突变如何引起魏德曼·斯坦纳综合症，一个 发育障碍，包括智力残疾和自闭症。最后，发现了MLL1依赖性 基因组调节元件的机制可能会引起更广泛的领域 神经发育，表观遗传学和干细胞生物学。我们的初步研究，V-SVZ和 染色质生物学以及我们与Aaron Diaz博士的产品合作（用于生物信息学创新和 支持），支持该项目的可行性。