Function and Structure Adaptations in Forebrain Development

前脑发育中的功能和结构适应

• 批准号: 8437219
• 负责人: PAT LEVITT
• 金额: $ 6.98万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2013-07-11
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8437219
• 关键词: Address; Affect; Alleles; Anxiety; Apical; Architecture; Area; Autopsy; Basic Science; Binding; Binding Sites; Biochemical; Biological Assay; Biological Models; Blood Cells; Brain; Cell Line; Cells; Cellular Morphology; Centers for Disease Control and Prevention (U.S.); Cerebral cortex; Characteristics; Child; Clinical; Clinical Research; Complex; CpG Islands; Data; Dendrites; Development; Disease; Dorsal; Electrophoretic Mobility Shift Assay; Engineering; Epigenetic Process; Excitatory Synapse; Forebrain Development; Fragile X Syndrome; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genetic Transcription; Goals; Growth; Health; Hepatocyte Growth Factor; Hippocampus (Brain); Human; Human Genetics; Immunoprecipitation; In Situ Hybridization; In Vitro; Individual; Injection of therapeutic agent; Interneurons; Knock-in Mouse; Knockout Mice; Lead; Ligands; MET gene; Methylation; Molecular; Mus; Mutate; Neocortex; Neuraxis; Neurons; Nuclear Extract; Nucleic Acid Regulatory Sequences; Patients; Peripheral; Phosphorylation; Process; Prosencephalon; Pyramidal Cells; Receptor Protein-Tyrosine Kinases; Regulation; Reporting; Research; Research Proposals; Risk; Role; SP1 gene; Seizures; Signal Transduction; Signaling Protein; Single Nucleotide Polymorphism; Small Interfering RNA; Social Behavior; Structure; Synapses; System; Temporal Lobe; Time; Tissues; Transcript; Transcription Initiation Site; Transcriptional Regulation; Translating; United States; Urokinase Plasminogen Activator Receptor; Variant; Western Blotting; autism spectrum disorder; brain tissue; calmodulin-dependent protein kinase II; developmental neurobiology; disorder control; functional disability; gene environment interaction; genetic manipulation; hippocampal pyramidal neuron; in vivo; in vivo Model; insight; lucifer yellow; meetings; mouse model; neocortical; nervous system development; neuron development; overexpression; postnatal; prenatal; pro-hepatocyte growth factor; promoter; protein expression; receptor; social; synaptic function; transcription factor; translational study

DESCRIPTION (provided by applicant): There are two related long-term goals of the proposed research. First, to determine the mechanisms through which the receptor tyrosine kinase Met signaling system influences forebrain development. Second, to define the relationship between MET gene regulation and altered forebrain development that may lead to functional impairments characteristic of autism spectrum disorder (ASD). MET and its ligand, hepatocyte growth factor (HGF), have been implicated in the development and maturation of neuronal circuits in vitro. In vivo, indirect genetic manipulation of HGF-Met signaling results in alterations in cortical interneuron development, intermittent seizures, increased anxiety and reduced social behavior in mice. Our preliminary data from the conditional deletion of Met in the neocortex provides direct evidence that Met signaling is involved in the structural and biochemical maturation of synapses. Moreover, we discovered that a single nucleotide polymorphism (SNP rs1858830) in the 52 transcriptional regulatory region of the human MET gene is strongly associated with ASD (P=5X10-6). This variant is functional, as it reduces gene transcription by interfering with transcription factor binding. This has clinical validity, as we have shown recently that MET protein expression is reduced to 50% of control levels in the temporal cortex of subjects with ASD compared to controls. The convergence of the human genetic and biochemical studies in ASD and basic developmental neurobiology suggests that MET signaling is important for the proper assembly of forebrain circuits, with dysregulation leading to functional disruptions in both model systems and in humans. In this renewal application, we propose to take advantage of the convergence of basic and clinical research data, organized around three specific aims to address the role of MET in neocortical development, the factors that contribute to MET gene regulation, and the influence of the ASD-associated human genetic regulatory variant on MET-related forebrain ontogeny. Aim 1 will determine the impact of direct elimination of Met signaling in the cerebral cortex using mice in which Emx1Cre conditionally deletes Met from the dorsal pallium. The goal of these studies is to define changes in dendritic and synaptic architecture, and in synaptic signaling systems. Aim 2 will define and experimentally manipulate, in cell lines, the transcription factors and assembled complex that regulate human MET gene transcription. The regulation of MET by epigenetic mechanisms in ASD cases of postmortem brains and peripheral cells from patients will be examined in methylation studies of the extensive CpG island in the 52 regulatory region of the gene. In Aim 3, new `humanized' mouse lines will be engineered that contain the human 52 regulatory sequence that has either the `G' or `C' rs1858830 allele and the CpG island. The goals of this aim are to determine how the ASD-associated `C' allele influences MET gene transcription and brain development in an in vivo model system, and to define the influence of epigenetic regulation of gene expression over time.

描述（由申请人提供）：拟议的研究有两个相关的长期目标。首先，确定受体酪氨酸激酶Met信号系统影响前脑发育的机制。第二，明确MET基因调控与可能导致自闭症谱系障碍（ASD）特征的前脑发育改变之间的关系。MET及其配体肝细胞生长因子（HGF）与体外神经元回路的发育和成熟有关。在体内，HGF-Met信号的间接遗传操作导致小鼠皮质中间神经元发育、间歇性癫痫发作、焦虑增加和社交行为减少的改变。我们从新皮层条件删除Met的初步数据提供了直接证据，表明Met信号参与突触的结构和生化成熟。此外，我们发现人类MET基因52转录调控区域的单核苷酸多态性（SNP rs1858830）与ASD密切相关（P=5X10-6）。这种变异是功能性的，因为它通过干扰转录因子结合来减少基因转录。这具有临床有效性，因为我们最近表明，与对照组相比，ASD受试者的颞叶皮层MET蛋白表达减少到控制水平的50%。ASD的人类遗传和生化研究与基础发育神经生物学的结合表明，MET信号对于前脑回路的正常组装很重要，而紊乱会导致模型系统和人类的功能中断。在这一更新申请中，我们建议利用基础和临床研究数据的融合，围绕三个具体目标来解决MET在新皮层发育中的作用，MET基因调控的因素，以及asd相关的人类基因调控变异对MET相关前脑个体发育的影响。目的1将确定直接消除大脑皮层Met信号的影响，使用Emx1Cre有条件地从背侧苍白质中删除Met的小鼠。这些研究的目的是确定树突和突触结构以及突触信号系统的变化。目标2将在细胞系中定义和实验操作调节人类MET基因转录的转录因子和组装复合体。在ASD患者死后大脑和外周细胞中，表观遗传机制对MET的调控将通过对该基因52个调控区域的CpG岛的甲基化研究来检验。在Aim 3中，新的“人源化”小鼠系将被设计成包含人类52调控序列，该序列具有“G”或“C”rs1858830等位基因和CpG岛。本研究的目的是在体内模型系统中确定asd相关的“C”等位基因如何影响MET基因转录和大脑发育，并确定随时间推移表观遗传调控基因表达的影响。