Loss of GTF2I promotes neuronal apoptosis and synaptic reduction in human cellular models of neurodevelopment. Loss of GTF2I promotes neuronal apoptosis and synaptic reduction in human cellular models of neurodevelopment

Individuals with Williams syndrome (WS), a multisystemic neurodevelopmental disorder, characteristically portray a hypersocial phenotype. WS is caused by the hemizygous loss of 26-28 genes at chromosomal locus 7q11.23, one of which is GTF2I. Copy number variations and mutations in GTF2I are associated with altered sociality and have been proposed to underlie the hypersocial expression of WS. However, the contribution of GTF2I to human neurodevelopment remains poorly understood. Here, human cellular models of neurodevelopment, including neural progenitors, neurons, and three-dimensional cortical organoids, were differentiated from CRISPR-Ca9-edited GTF2I-knockout (GTF2I-KO) pluripotent stem cells (hiPSCs) to investigate the role of GTF2I in human neurodevelopment. Compared to controls, GTF2I-KO progenitors exhibited an increased proliferation rate and an altered cell cycle profile. Cortical organoids and neurons demonstrated increased cell death and synaptic dysregulation, including synaptic structural dysfunction and decreased electrophysiological activity on a multi-electrode array. Overall, our findings suggest that changes in synaptic circuit integrity may be a prominent mediator of the link between alterations in GTF2I and variation in the phenotypic expression of human sociality. Overall design: Samples are two biological replicates each of two-month control and GTF2I-KO cortical organoids generated using the CVB hiPS cell line. Gene expression was compared between control and GTF2I-KO conditions.

威廉姆斯综合征（Williams syndrome, WS）是一种多系统神经发育障碍，患者特征性地呈现过度社交表型。该疾病由7q11.23染色体位点上26至28个基因的半合子缺失引发，其中一个基因为GTF2I。GTF2I的拷贝数变异与突变与社交行为改变相关，被认为是威廉姆斯综合征过度社交表型的潜在分子基础。然而，目前学界对GTF2I在人类神经发育中的贡献仍知之甚少。
本研究利用经CRISPR-Cas9编辑的GTF2I敲除（GTF2I-KO）人类多能干细胞（hiPSCs），分化得到神经前体细胞、神经元及三维皮质类器官等人类神经发育细胞模型，以探究GTF2I在人类神经发育中的作用。与对照组相比，GTF2I-KO神经前体细胞的增殖速率升高，细胞周期特征发生改变。皮质类器官与神经元则表现出细胞死亡增加、突触调控异常，包括突触结构功能障碍以及多电极阵列检测到的电生理活性降低。
综上，本研究结果提示，突触环路完整性的改变可能是GTF2I异常与人类社交表型变异之间关联的关键介导因素。
整体实验设计：本研究采用CVB hiPS细胞系构建样本，每组包含两份生物学重复，分别为培养两个月的对照组皮质类器官与GTF2I-KO皮质类器官，并对两组样本的基因表达水平进行了对比分析。