IBIS-iPSC: Organoid modeling of cortical surface area hyperexpansion in autism spectrum disorder

项目总结/摘要 许多患有单基因和特发性自闭症谱系障碍（ASD）的个体表现出脑 在生命的早期扩大。然而，导致早期脑损伤的潜在细胞和分子机制， ASD中的过度生长是未知的。为了确定导致大脑过度生长的机制，我们将使用 适当的模型系统，iPSC衍生的类器官，来自一个动力良好的，深度表型化的队列， 多个对照组，婴儿脑成像研究（IBIS）。IBIS是最大的纵向神经影像学研究 的婴儿（>250名参与者），由于有一个患有ASD的哥哥姐姐/先证者而具有自闭症的高家族风险。 重要的是，IBIS参与者之前在多个时间点进行了纵向神经成像， 婴儿期（6-24个月）和学龄期，在这些时间点进行广泛的行为评估， 以及罕见和常见的变异基因分型。在这个队列中产生的广泛的表型数据使其成为 一个理想的群体，从其中产生iPSC衍生的类器官模型，并在体外表型相关， 活体大脑生长和行为轨迹。我们的研究也代表了一个独特的机会，以评估如何 良好的类器官表型模拟了它们所来自的个体的体内脑生长轨迹 推导在这项提案中，我们将从血液中提取并验证iPSC，用于来自高危家庭的参与者， 患有ASD（HR+）的高风险参与者，未患ASD（HR-）的高风险参与者，以及未患ASD（HR-）的低风险个体。 ASD（LR-）共99例受试者。我们将iPSC细胞系与皮质类器官区分开来，以建立间质模型。 大脑发育的个体差异。我们将使用单细胞（sc）RNA-seq来鉴定细胞类型，细胞周期， 状态，以及在两个时间点上每个参与者衍生的类器官中的分化轨迹， 皮层神经发生期，共2.38M测序细胞。我们将验证细胞类型计数和状态 使用组织清除，然后对皮质类器官进行光片显微镜检查。我们将鉴定细胞类型，命运 决定，以及与横截面和纵向皮质表面积相关的细胞周期状态 随着时间的推移，生长和ASD症状以及认知能力。利用这一独特的，深刻的特点，临床 队列中，我们将确定皮质类器官的体内相关性以及细胞和分子的相关性。 ASD中大脑过度生长的潜在机制

Project Summary/Abstract Many individuals with monogenic and idiopathic forms of autism spectrum disorder (ASD) exhibit brain enlargement early in life. However, the underlying cellular and molecular mechanisms leading to early brain overgrowth in ASD are unknown. To identify the mechanisms leading to brain overgrowth, we will use an appropriate model system, iPSC-derived organoids, from a well-powered, deeply phenotyped cohort with multiple control groups, the Infant Brain Imaging Study (IBIS). IBIS is the largest longitudinal neuroimaging study of infants (>250 participants) at high familial risk for autism by virtue of having an older sibling/proband with ASD. Importantly, IBIS participants have previously undergone longitudinal neuroimaging at multiple time points in infancy (between 6-24 months of age) and school age, extensive behavioral assessments at these time points, as well as rare and common variant genotyping. The extensive phenotypic data generated in this cohort make it an ideal population from which to generate iPSC-derived organoid models and relate in vitro phenotypes to in vivo brain growth and behavioral trajectories. Our study also represents a unique opportunity to evaluate how well organoid phenotypes model the in vivo brain growth trajectories of the individual from whom they were derived. In this proposal, we will derive and validate iPSCs from blood for participants from high risk families who developed ASD (HR+), high risk participants who did not develop ASD (HR-), and low risk individuals without ASD (LR-) totaling 99 participants. We will differentiate the iPSC lines to cortical organoids to model inter- individual differences in brain development. We will use single cell (sc)RNA-seq to identify cell types, cell cycle states, and differentiation trajectories in each participant-derived organoid across two time points modeling the period of cortical neurogenesis, totaling 2.38M sequenced cells. We will validate cell type counts and states using tissue clearing followed by lightsheet microscopy of the cortical organoids. We will identify cell types, fate decisions, and cell cycle states that correlate with both cross-sectional and longitudinal cortical surface area growth and ASD symptoms and cognitive ability over time. Leveraging this unique, deeply characterized clinical cohort, we will determine both the in vivo relevance of cortical organoids and the cellular and molecular mechanisms underlying brain overgrowth in ASD.