Elucidating the molecular mechanisms behind human neurodevelopmental disorders using brain organoids

项目总结 神经发育和神经精神障碍是一个全球性的健康问题；但令人惊讶的是，人们对此知之甚少。 关于它们在人类中的神经学基础。因此，治疗选择仍然有限。……的到来 指导人类胚胎和诱导多能干细胞形成神经元的方法 (统称为hPSC)提供了前所未有的机会来研究人类的功能 神经回路被神经系统疾病颠覆，并筛选新的治疗方法。朝着这些目标迈出的重要一步 目标已经通过有机培养技术的发展而实现，通过这种技术hPSC可以 旨在形成空间上有组织的、类似大脑的结构。到目前为止，脑有机化合物已经成功地 用来模拟基因突变和环境病原体造成的明显缺陷的影响 大脑发育。然而，在大多数神经性疾病中，整体大脑结构都被保存下来，缺陷是 主要由神经活动的改变来定义。因此，在开发方法方面仍然存在重大挑战 定义有机化合物中神经网络的组织和功能，并使用这种方法来探索 潜在的疾病机制和治疗机会。在我们最近的工作中，我们发现 非常复杂的神经网络活动可以通过皮质-神经节隆起的产生而出现 融合有机体，它允许兴奋性和抑制性神经元的混合和功能耦合。 结合钙传感器成像和电生理方法，我们鉴定了这种融合 有机化合物表现出持续的多频神经振荡，这让人想起在 完整的大脑样本和切片培养。我们进一步发展了一种融合有机体模型 神经发育障碍Rett综合征并发现MECP2中含有突变的有机化合物 基因表现出明显的异常神经网络活动，包括超同步爆发的发作， 中低频率振荡节律丧失，癫痫样高频异常出现 震荡。总而言之，这些研究说明了融合有机化合物平台的非凡潜力 报告神经网络功能正常和功能障碍，并总结显著的病理特征 可见于RETT患者，如癫痫发作。在这里，我们试图解决三个核心问题，以澄清 与Rett综合征等相关的神经网络功能障碍的机制 神经发育障碍。首先，雷特综合征患者是否存在神经网络功能障碍？ 由携带不同突变的患者产生的基因与突变的性质相关吗？第二，什么 MECP2功能中的细胞嵌合体对神经网络活动有影响吗？第三，做器官模型 对于具有癫痫成分的不同神经系统疾病，表现为共享或不同的网络功能障碍 个人资料？通过我们的研究，我们将探索如何最好地利用大脑有机化合物来确定根 导致一系列人类神经病变的原因，并朝着发现新疗法的目标努力。

PROJECT SUMMARY Neurodevelopmental and neuropsychiatric disorders are a global health problem; yet remarkably little is known about their neurological basis in humans. Consequently, treatment options remain limited. The advent of methods to direct the formation of neurons from human embryonic and induced pluripotent stem cells (collectively hPSCs) provides unprecedented opportunities to both investigate how the function of human neural circuits is subverted by neurological disease and screen for new therapies. A major step towards these goals has been realized by the development of organoid culture techniques through which hPSC can be directed to form spatially organized, brain-like structures. Thus far, brain organoids have been successfully employed to model the impact of genetic mutations and environmental pathogens that result in overt defects in brain growth. However, overall brain structure is preserved in most neurological disorders, and defects are primarily defined by alterations in neural activities. Major challenges thus remain in developing means for defining the organization and function of neural networks within organoids and using this approach to explore underlying disease mechanisms and therapeutic opportunities. In our recent work, we discovered that remarkably complex neural network activities can emerge through the creation of cortex-ganglionic eminence fusion organoids, which permits the intermixing and functional coupling of excitatory and inhibitory neurons. Using a combination of calcium sensor imaging and electrophysiological approaches, we identified that fusion organoids exhibit sustained multifrequency neural oscillations reminiscent of higher network functions seen in intact brain samples and slice cultures. We further developed a fusion organoid model for the neurodevelopmental disorder Rett syndrome and found that organoids harboring mutations in the MECP2 gene exhibit markedly abnormal neural network activities including episodes of hypersynchronous bursting, loss of low-to-mid frequency oscillatory rhythms, and abnormal appearance of epileptiform high frequency oscillations. Together, these studies illustrate the extraordinary potential for the fusion organoid platform to report both normal and dysfunctional neural network functions and recapitulate salient pathological features seen in Rett patients such as seizures. Here, we seek to address three central questions for elucidating the mechanisms underlying neural network dysfunction associated with Rett syndrome and other neurodevelopmental disorders. First, does neural network dysfunction seen in Rett syndrome organoids generated from patients harboring different mutations correlate with the nature of the mutation? Second, what is the impact of cellular mosaicism in MECP2 function on neural network activities? Third, do organoid models for different neurological diseases with a seizure component exhibit shared or distinct network dysfunction profiles? Through our studies, we will explore how brain organoids can be best utilized to determine the root causes of a range of human neuropathologies and work towards the goal of discovering new treatments.