Chandellier interneurons and the excitation/inhibition balance in the human prefrontal cortex in autism

自闭症患者前额叶皮质Chandellier中间神经元与兴奋/抑制平衡 人们对自闭症大脑皮层的病理知之甚少。我们之前资助的R01的目标是 格兰特将揭开自闭症患者大脑皮层的病理。具体地说，我们建议 发现哪种细胞类型(S)，如果有的话，在人类自闭症病例的大脑皮层中发生改变。我们量化了 人体各层锥体神经元、特定亚型中间神经元和神经胶质细胞的数量 自闭症患者的颞叶和前额叶皮质。我们测定了锥体神经元和神经胶质细胞的数量 在自闭症患者的颞叶大脑皮层中，与典型的发育中的对照组患者没有不同， 并在几篇研究文章中发表了我们的结果(Camacho等人，2014年；Kim等人，2015年)。然而，我们 发现在前额叶皮质中有一种特定的神经元间亚型的数量减少 在自闭症病例中，副蛋白(PV)Chandellier细胞(Hashemi等人，2016)。吊灯(CH)细胞是 皮质中的主要中间神经元，其轴突直接与锥体的起始段相连 轴突，形成一种突出的结构，称为“卡特里奇”。因此，CH细胞是主要的神经元间质 调节兴奋性投射神经元最终输出的亚型。因此，损失了一小部分 CH细胞可能严重损害锥体细胞和大脑皮层的整体功能。的确，变化 在CH细胞中，盒/管和/或功能以前在神经系统疾病中被报道，例如 精神分裂症和癫痫。基于我们的发现，我们建议通过以下方式定义CH细胞在自闭症中的作用 解开它们的形态和连接属性。 我们假设，我们在自闭症皮质中发现的PV CH细胞数量的减少可以转化为 CH细胞盒数量的减少和每个盒的突触按钮数量的减少， 随之而来的是锥体神经元轴突起始节段CH对称性突触的丢失，以及 最终损害了皮质投射神经元的功能。我们还假设有一个减少的 锥体轴突内GABA及GABA相关蛋白和GABRAα2受体的含量 初始段。这种抑制性突触结构的减少将导致皮质突触的过度兴奋 自闭症的回路。此外，我们假设在自闭症患者中， 患者症状的严重程度和CH细胞的数量。 我们将确定CH单元盒的数量和长度是否有变化(Aim1)，如果有 CH弹中GABA能系统的改变(目标2)，以及如果轴突数目发生改变- 自闭症尸检大脑前额叶皮质(BA9、BA45、BA46)的轴突突触(AIM 3)。我们会 用免疫组织化学标记试剂盒和GABA相关蛋白，用高尔基染色标记CH细胞，并进行分析 3D电子显微镜观察突触结构。我们将使用立体调查员NeuroLucida分析数据， 图像J、FIB/SEM EM和高通量三维重建。我们将对自闭症患者的数据进行关联 具有特定症状和其他患者特征的组(目标1-3)。 提供自闭症大脑皮层中GABA系统元素的全面量化 有必要将自闭症研究领域推向一个新的方向。这个项目将提供一个彻底的 了解自闭症患者大脑皮层中的GABA能系统，并将对其产生重大影响 关于旨在为自闭症患者提供新治疗方法的转化性研究。 好了！

Chandellier interneurons and the excitation/inhibition balance in the human prefrontal cortex in autism Little is known about the pathology of the cerebral cortex in autism. The goal of our previously funded R01 grant was to unravel the pathology of the cerebral cortex in patients with autism. Specifically, we proposed to discover which cell type(s), if any, are altered in the cerebral cortex of human autistic cases. We quantified the number of pyramidal neurons, specific subtypes of interneurons, and glial cells, within each layer of the human temporal and prefrontal cortex in autism. We determined that the number of pyramidal neurons and glial cells in the temporal cerebral cortex of autistic cases did not differ from that in typically developing control cases, and published our results in several research articles (Camacho et al., 2014; Kim et al., 2015). However, we discovered that there is a decrease in the number of one specific interneuronal subtype in the prefrontal cortex of autistic cases, the parvalbumin (PV)+ Chandellier cell (Hashemi et al., 2016). Chandellier (Ch) cells are the main interneuron in the cortex possessing axons that synapse directly on the initial segment of the pyramidal axon, creating a prominent structure called “cartridge”. Consequently, the Ch cell is the main interneuronal subtype that regulates the final output of excitatory projection neurons. Therefore, the loss of a small number of Ch cells may critically impair function of pyramidal cells and of the cerebral cortex as a whole. Indeed, changes in Ch cells cartridges/boutons and/or function have previously been reported in neurological diseases, such as schizophrenia and epilepsy. Based on our discovery, we propose to define the role of Ch cells in autism by unraveling their morphological and connectional properties. We hypothesize that the decreased number of PV+ Ch cells we discovered in the autistic cortex translates into a decrease in the number of Ch cell cartridges and a decrease in the number of synaptic buttons per cartridge, with the consequent loss of Ch symmetric synapses on the pyramidal neuron axonal initial segment, and ultimately impaired function of cortical projection neurons. We also hypothesize that there is a decreased amount of GABA and GABA related proteins per cartridge, and of GABRAα2 receptors in the pyramidal axonal initial segment. This reduction of inhibitory synapse structure would cause hyperexcitation of cortical synaptic circuits in autism. Additionally, we hypothesize that in autism there is a negative correlation between the severity of the patient' symptoms and the number of Ch cells. We will determine if there is an alteration in the number and length of Ch cell cartridges (Aim1), if there is an alteration in the GABAergic system in Ch cartridges (Aim 2), and if there is an alteration in the number of axo- axonic synapses (Aim 3) in the prefrontal cortex (BA9, BA45, BA46) of the autism postmortem brain. We will label cartridges and GABA related proteins with immunochemistry, Ch cells with Golgi staining, and analyze synapse structure with 3D electronic microscopy. We will analyze data using Stereoinvestigator, Neurolucida, Image J, FIB/SEM EM, and high-throughput 3D reconstruction. We will correlate data obtained for the autistic group (Aim 1-3) with specific symptoms and other patient characteristics. Providing a comprehensive quantification of the elements of the GABA system in the autism cerebral cortex is necessary to move the field of autism research in a new direction. This project will provide a thorough understanding of the GABAergic system in the human cerebral cortex in autism, and will have a great impact on translational research directed towards providing novel treatment for individuals with autism. !