Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan.
Department of Neurology, Faculty of Medicine, Nara Medical University, Kashihara, Nara, 634-8521, Japan.
Mol Brain. 2021 Nov 8;14(1):163. doi: 10.1186/s13041-021-00874-8.
We have reported that the transcription factor Olig2 labels a subpopulation of astrocytes (Olig2-astrocytes), which show distribution patterns different from those of GFAP-expressing astrocytes (GFAP-astrocytes) in the adult brain. Here, to uncover the specific functions of Olig2-astrocytes, we first analyzed public single-cell RNA-seq databases of adult mouse brains. Unbiased classification of gene expression profiles and subsequent gene ontology analyses revealed that the majority of Olig2-astrocytes belonged to an astrocytic cluster that is enriched for transporter-related genes. SLC7A10 (also known as ASC-1) was one of the representative neutral amino acid transporter genes in the cluster. To complement the in silico data analyses, we differentially isolated Olig2- and GFAP-astrocytes from the same frozen section of the lateral globus pallidus using laser microdissection and compared their gene expression by quantitative reverse transcription PCR. We confirmed that Olig2 and GFAP mRNAs were preferentially expressed in the Olig2- and GFAP-astrocytes, respectively, indicating that the laser microdissection method yielded minimal cross-contamination between two types of cells. The Olig2-astrocytes expressed significantly higher levels of SLC7A10 mRNA than the GFAP-astrocytes, corroborating the in silico data. We next localized SLC7A10 protein by immunohistochemistry in the lateral globus pallidus, which was also genetically labeled for Olig2. SLC7A10 co-localized with Olig2-genetic labeling, especially on the fine processes of Olig2-astrocytes. These results are consistent with the recent discovery that SLC7A10 is expressed not only in neurons but also in a subset of astrocytes. Taken together, our findings suggest that SLC7A10 exerts specific functions in Olig2-astrocytes of the adult brain.
我们曾报道过转录因子 Olig2 标记了星形胶质细胞的一个亚群（Olig2-星形胶质细胞），其在成年大脑中的分布模式与 GFAP 表达的星形胶质细胞（GFAP-星形胶质细胞）不同。在这里，为了揭示 Olig2-星形胶质细胞的特定功能，我们首先分析了成年小鼠大脑的公共单细胞 RNA-seq 数据库。对基因表达谱进行无偏分类和随后的基因本体分析表明，大多数 Olig2-星形胶质细胞属于富含转运体相关基因的星形胶质细胞簇。SLC7A10（也称为 ASC-1）是该簇中代表性的中性氨基酸转运体基因之一。为了补充计算机数据分析，我们使用激光微切割从外侧苍白球的同一冷冻切片中差异分离出 Olig2-和 GFAP-星形胶质细胞，并通过定量逆转录 PCR 比较它们的基因表达。我们证实 Olig2 和 GFAP mRNA 分别优先在 Olig2-和 GFAP-星形胶质细胞中表达，表明激光微切割方法在两种类型的细胞之间产生的交叉污染最小。Olig2-星形胶质细胞中 SLC7A10 mRNA 的表达水平明显高于 GFAP-星形胶质细胞，与计算机数据相符。接下来，我们通过免疫组织化学在外侧苍白球中定位 SLC7A10 蛋白，该区域也遗传标记为 Olig2。SLC7A10 与 Olig2 遗传标记共定位，尤其是在 Olig2-星形胶质细胞的细突起上。这些结果与最近的发现一致，即 SLC7A10 不仅在神经元中表达，而且在星形胶质细胞的一个亚群中表达。总之，我们的研究结果表明，SLC7A10 在成年大脑中的 Olig2-星形胶质细胞中发挥特定功能。
