Regional characterization of astrocytes in the human brain

前言：直到20世纪90年代，星形胶质细胞一直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性支持。现在清楚的是，星形胶质细胞是高度动态的细胞，扮演着对大脑网络的正常功能至关重要的各种角色。然而，我们目前对这些细胞的形态功能特性的了解主要来自于动物模型的研究，特别是啮齿动物。尽管啮齿动物和人脑的基本组织有许多相似之处，但在细胞水平上可能存在重大差异。我们和其他小组的工作最近表明，人类大脑皮层星形胶质细胞比啮齿动物要复杂得多，也更加多样化。尽管有这些最近的发现，但关于人脑中星形胶质细胞的细胞和亚细胞组织以及分子特性仍有许多有待发现的地方。特别是，关于星形胶质细胞在其他非皮质脑区的形态和分子特征几乎一无所知。*主要和具体目标：本研究计划的主要目标是描述在人脑不同区域发现的星形胶质细胞亚型的分布、形态和转录特征。更具体地说，我们将使用精细的神经解剖学和分子学方法，定性和定量地描述星形胶质细胞在不同皮质和皮质下脑区的分布和细胞/亚细胞特性，并以细胞群体特有的方式表征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特征良好的固定和冷冻死后脑标本。这些样本将来自健康的35-40岁的男性和女性捐赠者，他们没有精神、神经或慢性炎症病史。我的实验室中常规使用的最先进的方法将被用来量化区域星形细胞密度和形态特征。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，将通过激光捕获显微切割提取星形胶质细胞，并通过超低输入RNA测序确定它们的转录图谱。*意义：预计这项研究将导致新的星形胶质细胞亚型的识别，并将出现星形胶质细胞网络的独特的区域特征。这将使我们能够更好地了解人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.