Regional characterization of astrocytes in the human brain

简介：直到20世纪90年代，星形胶质细胞在很大程度上被认为是中枢神经系统的被动组成部分，主要为神经元提供结构支持。现在很清楚，星形胶质细胞是高度动态的细胞，发挥着各种作用，这些作用对大脑网络的正常功能至关重要。然而，我们目前对这些细胞的形态功能特性的了解基本上来自对动物模型，特别是啮齿动物进行的研究。尽管啮齿动物和人类大脑的基本组织有许多相似之处，但在细胞水平上可能存在显着差异。我们和其他研究小组的工作最近表明，人类皮质星形胶质细胞比啮齿类动物的同类细胞更复杂和多样。尽管这些最近的发现，仍有许多有待发现的细胞和亚细胞的组织和分子特性的星形胶质细胞在人脑中。特别是，几乎没有什么是已知的形态和分子特征的星形胶质细胞在其他非皮层，大脑区域。 主要和具体目标：这项研究计划的主要目标是表征在人脑不同区域发现的星形胶质细胞亚型的分布，形态和转录谱。更具体地说，我们将使用精细的神经解剖学和分子的方法来描述，定性和定量，星形胶质细胞的分布和细胞/亚细胞特性在不同的皮质和皮质下的大脑区域，并表征在细胞群体特异性的方式区域星形胶质细胞基因表达谱。 方法：将从道格拉斯-贝尔加拿大脑库获得表征良好的固定和冷冻死后脑样本。这些样本将来自健康的35-40岁男性和女性供体，无精神病、神经系统或慢性炎症病史。国家的最先进的方法，经常使用在我的实验室将被用来量化区域星形胶质细胞的密度和形态特征。这些包括免疫染色细胞的体视学定量和3D细胞重建。在每个区域中，将通过激光捕获显微切割提取星形胶质细胞，并在超低输入RNA测序后确定其转录组学谱。 重要性：预计这项研究将导致新的星形胶质细胞亚型的鉴定，星形胶质细胞网络的独特区域特性将出现。这将使我们更好地了解人类大脑的精细结构和功能组织。

Introduction: Until the 1990s, astrocytes were largely considered to be passive components of the central nervous system, providing mainly structural support for neurons. It is now clear that astrocytes are highly dynamic cells that play a variety of roles that are essential for the proper function of cerebral networks. However, our current knowledge on the morpho-functional properties of these cells comes essentially from studies conducted with animal models, rodents in particular. Despite the many similarities in the basic organization of rodent and human brains, significant differences can exist at the cellular level. Our work as well as that of other groups has recently shown that human cortical astrocytes are much more complex and diverse than their rodent counterparts. Despite these recent findings, much remains to be discovered regarding the cellular and subcellular organization and molecular properties of astrocytes in the human brain. In particular, virtually nothing is known about the morphometric and molecular features of astrocytes in other, non-cortical, brain regions. Main and specific objectives: The main objective of this research program is to characterize the distributional, morphometric and transcriptomic profiles of astrocytic subtypes found in different regions of the human brain. More specifically, we will use fine neuroanatomical and molecular approaches to describe, qualitatively and quantitatively, the distribution and cellular/subcellular properties of astrocytes in various cortical and subcortical brain regions, and characterize in a cell population-specific manner the regional astrocytic gene expression profiles. Methods: Well-characterized fixed and frozen postmortem brain samples will be obtained from the Douglas-Bell Canada Brain Bank. These samples will come from healthy 35-40 year-old male and female donors with no history of psychiatric, neurological, or chronic inflammatory conditions. State-of-the-art approaches routinely used in my laboratory will be employed to quantify regional astrocytic densities and morphological features. These include stereological quantifications of immunostained cells and 3D cell reconstructions. In each region, astrocytes will be extracted by laser-capture microdissection, and their transcriptomic profiles determined following ultra-low input RNA sequencing. Significance: It is expected that this research will lead to the identification of new astrocytic subtypes, and that distinct regional properties of astrocytic networks will emerge. This will allow us to better understand the fine structural and functional organization of the human brain.