Cellular and Genetic Correlates of Increased Head Size in Autism Spectrum Disorde

描述（由申请人提供）：我们的项目利用了最近的方法，允许从成纤维细胞中提取多能干细胞，这些成纤维细胞可以通过活体皮肤活检获得。这些诱导多能干细胞（iPSC）可以分化为身体的任何细胞类型，包括神经干细胞（NSCs）。我们将使用这些方法来研究自闭症谱系障碍（ASD）中的神经元分化。我们的假设表明，ASD中高度复制的生物表型——脑体积增加，可归因于NSCs固有的细胞增殖和/或分化动力学的改变，而这反过来又与基因表达的特定变化以及基因组序列和/或表观基因组印迹的潜在变化相关。为了验证这一假设，我们召集了一组具有必要的专业知识的研究人员，以多层次和多维度的方法来解决这个问题。在Specific Aim 1中，我们将从显示头部大小增加的ASD患者和正常发育的儿童中获得iPSC系。这些iPSC系将分化为NSCs。将来自ASD个体的NSC系与来自正常发育个体的NSC系在增殖、细胞死亡和分化为不同神经元亚型以及突触规范方面进行比较。在Specific Aim 2中，我们将使用先进的基因组学和表观基因组学技术来生成高分辨率和全面的数据集，这些数据集包括基因组序列、表观遗传标记以及神经元细胞分化的祖细胞和成熟阶段的转录物丰度。我们将整合多层次基因组学和基因表达数据集与细胞生物学和临床表型的发现。在特异性目标3中，我们将把来自对照组和患者的NSCs移植到小鼠胚胎的心室中，以确定它们的体内表型和它们向不同脑区域贡献神经元的能力。我们研究的潜在影响是开发直接来源于患者的细胞系，这些细胞系将在体外重现使胚胎干细胞分化为多种中枢神经系统细胞类型的生物学步骤。该项目将为开始关联基因组序列、基因表达的调节和强度、细胞（生物学）后果和患者行为奠定基础，从而了解疾病的生物学机制。在iPSC系中发现的候选基因和区域随后可以在有针对性的大规模筛选中进行具有统计学意义的验证。直接分析与个体患者及其临床表型相关的基因表达和调控的具体差异可能为疾病发病机制提供独特的见解。

DESCRIPTION (provided by applicant): Our project capitalizes on recent procedures that allow derivation of pluripotent stem cells from fibroblasts obtainable through a small skin biopsy from living individuals. These induced pluripotent stem cells (iPSC) can differentiate into any cell types of the body, including neural stem cells (NSCs). We will use these methods to investigate neuronal differentiation in autism spectrum disorders (ASD). Our hypothesis states that increased brain size, a highly replicated biological phenotype in ASD, is attributable to altered dynamics of cell proliferation and/or differentiation intrinsic to NSCs, which, in turn, will correlate with specific changes in gene expression and the underlying changes in genomic sequence and/or epigenomic imprinting. To test this hypothesis, we have assembled a group of investigators with the range of expertise necessary for a multi-level and multi-dimensional approach to this problem. In Specific Aim 1, we will derive iPSC lines from patients with ASD exhibiting an increase in head size and from typically developing children. These iPSC lines will be differentiated into NSCs. The NSC lines from ASD individuals will be compared to those derived from typically developing individuals with respect to their proliferation, cell death and differentiation into different neuronal subtypes, as well as synaptic specification. In Specific Aim 2, we will use advanced genomics and epigenomics technologies to generate high-resolution and comprehensive datasets of variation in the genomic sequence, epigenetic marks, and transcript abundance at progenitor and mature stages of neuronal cell differentiation. We will integrate multi-level genomics and gene expression datasets with findings from cell biology and clinical phenotypes. In Specific Aim 3, we will transplant NSCs from control and patients into the ventricles of mouse embryos in order to determine their in vivo phenotype and their ability to contribute neurons to various brain regions. The potential impact of our research is to develop cell lines derived directly from patients that will recapitulate in vitro the biological steps that enable an embryonic stem cell to differentiate into multiple CNS cell types. This project will lay the foundations for beginning to correlate genomic sequence, regulation and intensity of gene expression, cellular (biological) consequences, and patient behavior, and thus understand the biological mechanisms of disease. Candidate genes and regions found in iPSC lines can be subsequently validated with statistical significance in targeted large-scale screens. The direct analysis of specific differences in gene expression and regulation that pertain to individual patients and their clinical phenotype may offer unique insights into disease pathogenesis. PUBLIC HEALTH RELEVANCE: This project will develop lines of pluripotent cells (iPSC) from individuals with autism spectrum disorders and typically developing children using cells obtained through a skin biopsy. These iPSC will be differentiated into neuronal cells, allowing us to investigate for the first time differences in neural cells proliferation, differentiation and survival in patients and controls, and to correlate such differences with underlying changes in gene expression and in the genomic sequence. The analysis of gene expression and regulation in neural cells that pertain to individual patients and their clinical phenotype may offer unique insights into disease pathogenesis.