Chen Di, Ren Keke, Liu Haiying, Mao Honghui, Li Zongyan, Mo Huiming, Xie Shengjun, Shi Yiwu, Chen Qian, Wang Wenting
Institute of Neuroscience, Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China.
Front Cell Neurosci. 2020 Jun 5;14:145. doi: 10.3389/fncel.2020.00145. eCollection 2020.
Single neurons, as the basic unit of the brain, consist of a cell body and processes, including dendrites and axons. Even neurons of the same type show various subtle process characteristics to fit into the diverse neural circuits. Different cell types of neurons form complicated circuits in the brain. Therefore, detailed neuronal morphology is required to understand normal neuronal function and pathological mechanisms, such as those that occur in autism. Here, we developed a strategy to sparsely label the same type of neurons throughout the whole brain and tested its application in an autistic animal model- knockout (KO) mice. To achieve this, we designed an adeno-associated virus (AAV) that expresses Cre recombinase-dependent regular and membrane-targeted enhanced green fluorescent protein (EGFP) under a human synapsin 1 promoter and verified it in several Cre transgenic mice. We could sparsely label the projection neurons in multiple brain areas by retro-ocular injection of the virus into CaMKIIα-Cre mice. Then, we analyzed the morphology of the projection neurons in KO mice with this method. We found differential dendritic complexity and dendritic spine changes in projection neurons in KO mice crossed with CaMKIIα-Cre mice compared with littermate control mice in the striatum, cortex, and hippocampus. By combining this method with various Cre mouse lines crossed with mouse models of disease, we can screen the morphological traits of distinct types of neurons throughout the whole brain that will help us to understand the exact role of the specific cell types of neurons not only in autism spectrum disorder (ASD) mouse models but also in other psychiatric disorder mouse models.
单个神经元作为大脑的基本单位，由细胞体和突起组成，包括树突和轴突。即使是同一类型的神经元也表现出各种细微的突起特征，以适应不同的神经回路。不同类型的神经元细胞在大脑中形成复杂的回路。因此，需要详细的神经元形态来理解正常的神经元功能和病理机制，例如自闭症中出现的那些机制。在这里，我们开发了一种策略，在整个大脑中稀疏标记同一类型的神经元，并在自闭症动物模型——基因敲除（KO）小鼠中测试了其应用。为了实现这一点，我们设计了一种腺相关病毒（AAV），它在人突触素1启动子的控制下表达依赖于Cre重组酶的常规和膜靶向增强型绿色荧光蛋白（EGFP），并在几只Cre转基因小鼠中进行了验证。通过将病毒经眼后注射到CaMKIIα-Cre小鼠中，我们可以在多个脑区稀疏标记投射神经元。然后，我们用这种方法分析了KO小鼠中投射神经元的形态。我们发现，与纹状体、皮层和海马体中的同窝对照小鼠相比，与CaMKIIα-Cre小鼠杂交的KO小鼠的投射神经元在树突复杂性和树突棘变化方面存在差异。通过将这种方法与各种与疾病小鼠模型杂交的Cre小鼠品系相结合，我们可以筛选出整个大脑中不同类型神经元的形态特征，这将有助于我们不仅了解自闭症谱系障碍（ASD）小鼠模型中特定类型神经元的确切作用，还能了解其他精神疾病小鼠模型中特定类型神经元的确切作用。
