Cortical organoid models to study autism-associated 16p.11.2.CNV

摘要 包含29个基因的16p11.2拷贝数变异体(CNV)代表着最强的风险因素之一 神经发育障碍。它是所有与自闭症谱系有关的罕见CNV中最常见的 精神障碍(ASD)。该基因座的缺失(Del)和重复(DUP)都与ASD密切相关， 而Del也与智力残疾有关，DUP也与精神分裂症有关。 16p11.2 CNV剂量对人类携带者脑体积和体重指数(BMI)具有镜像效应 被诊断为自闭症。在DEL携带者中观察到大头畸形和高BMI，而小头畸形和低体重指数 在复制载体中观察到BMI。令人惊讶的是，16p11.2 Del和DUP小鼠模型有大脑和 体型表型与人类携带者相反。尽管这种CNV很重要，但详细的分子 在大脑早期发育过程中被破坏的机制仍不清楚。我们最近生成了诱导式 16p11.2 DEL和DUP患者成纤维细胞的多能干细胞和脑有机体 极端头部大小的表型。脑器官重现了患者的脑大小表型。过剩神经元 在DEL中观察到神经前体细胞的数量和枯竭，在DUP中观察到“镜像”表型。此外, 神经元迁移和突触缺陷被发现，这与Rho/Wnt信号有关。中心假说 这一建议的核心是16p11.2 CNV剂量(DEL或DUP)通过改变 不同神经元(亚)类型的比率以及对其电生理特性的干扰。为了测试 在这一假设下，我们将：(1)研究16p11.2 CNV如何影响细胞类型和染色质 (2)研究16p11.2 CNV如何影响突触传递和 用全细胞膜片钳和多电极阵列(MEA)记录有机物中的振荡网络活动 通过挽救分子和细胞表型来研究Rho/Wnt和其他信号通路的参与 Del和DUP有机化合物。我们的研究有可能揭示16p11.2CNV背后的新机制 自闭症。

SUMMARY The 16p11.2 Copy Number Variant (CNV) containing 29 genes represents one of the strongest risk factors for neurodevelopmental disorders. It is the most common among all rare CNVs implicated in Autism Spectrum Disorder (ASD). Both, deletions (DEL) and duplications (DUP) of this locus are strongly associated with ASD, whereas DEL are also associated with intellectual disability, and DUP are also associated with schizophrenia. The 16p11.2 CNV dosage has “mirror” effect on the brain volume and body mass index (BMI) in human carriers diagnosed with ASD. Macrocephaly and high BMI are observed in the DEL carriers, and microcephaly and low BMI are observed in the duplication carriers. Surprisingly, 16p11.2 DEL and DUP mouse models have brain and body size phenotypes opposite to human carriers. Despite the importance of this CNV, the detailed molecular mechanisms that are disrupted during early brain development remain unknown. We recently generated induced pluripotent stem cells (iPSCs) and cerebral organoids from fibroblasts of 16p11.2 DEL and DUP patients with extreme head size phenotypes. Cerebral organoids recapitulated patients’ brain size phenotypes. Excess neuron number and depletion of neuroprogenitors was observed in DEL, with a “mirror” phenotypes in DUP. In addition, neuron migration and synaptic defects were identified, implicating Rho/Wnt signaling. The central hypothesis of this proposal is that that 16p11.2 CNV dosage (DEL or DUP) impacts brain development by altering the ratio of different neuronal (sub)types and by perturbing their electrophysiological properties. To test this hypothesis, we will: (1) Investigate how 16p11.2 CNV impacts cell type populations and chromatin accessibility at the single cell resolution; (2) Investigate how 16p11.2 CNV affects synaptic transmission and oscillatory network activity in organoids using whole-cell patch-clamp and multielectrode array (MEA) recordings; Investigate involvement of Rho/Wnt and other signaling pathways by rescuing molecular and cellular phenotypes of DEL and DUP organoids. Our study has a potential to uncover new mechanisms behind 16p11.2 CNV in autism.