Astrocytes release glutamate via cystine/glutamate antiporter upregulated in response to increased oxidative stress related to sporadic amyotrophic lateral sclerosis.
Astrocytes release glutamate via cystine/glutamate antiporter upregulated in response to increased oxidative stress related to sporadic amyotrophic lateral sclerosis.
复制标题
星形胶质细胞通过胱氨酸/谷氨酸逆向转运蛋白释放谷氨酸，以响应与散发性肌萎缩侧索硬化症相关的氧化应激增加。
DOI：
10.1111/neup.12716
复制
发表时间：
2020
期刊：
影响因子：
2.3
通讯作者：
Shibata N.
中科院分区：
文献类型：
--
作者：
Kazama M;Kato Y;Kakita A;Noguchi N;Urano Y;Masui K;Niida-Kawaguchi M;Yamamoto T;Watabe K;Kitagawa K;Shibata N.
大量证据表明，在散发性肌萎缩性侧索硬化症（ALS）的病理机制中，氧化应激和细胞外谷氨酸积累的增加。胱氨酸/谷氨酸反转运蛋白（xCT）在氧化应激下进行细胞外胱氨酸摄取和细胞内谷氨酸释放（胱氨酸/谷氨酸交换）。本研究的目的是确定xCT在ALS中的作用。脊髓切片的免疫组化观察表明，xCT主要在星形胶质细胞中表达，与12名年龄匹配的对照个体相比，12名散发性ALS患者的xCT染色更强烈。脊髓样品的Western blot和密度分析显示，与对照组相比，ALS组的xCT/β - actin光密度比的相对值显著升高。接下来，我们使用人类星形细胞瘤来源的细胞系（1321N1）和小鼠运动神经元/神经母细胞瘤杂交细胞系（NSC34）进行细胞培养实验。在1321N1细胞中，h2o2处理显著提高了细胞裂解物中归一化xCT的表达水平。H2O2处理显著提高了1321 N1细胞培养条件培养基中的谷氨酸浓度，而xCT抑制剂erastin预处理完全抵消了H2O2驱动的升高。在运动神经元分化的NSC34细胞（NSC34d细胞）中，无论是否经过h2o2处理，细胞裂解物中标准化的xCT表达水平和细胞条件培养基中的谷氨酸浓度都是恒定的。目前的研究结果提供了体内和体外证据，表明星形胶质细胞上调xCT表达以释放谷氨酸，以响应与ALS相关的氧化应激增加，从而促进细胞外谷氨酸积累。
A vast body of evidence implicates increased oxidative stress and extracellular glutamate accumulation in the pathomechanism of sporadic amyotrophic lateral sclerosis (ALS). Cystine/glutamate antiporter (xCT) carries extracellular cystine uptake and intracellular glutamate release (cystine/glutamate exchange) in the presence of oxidative stress. The aim of the present study was to determine the involvement of xCT in ALS. Immunohistochemical observations in the spinal cord sections demonstrated that xCT was mainly expressed in astrocytes, with staining more intense in 12 sporadic ALS patients as compared to 12 age‐matched control individuals. Western blot and densitometric analyses of the spinal cord samples revealed that the relative value of xCT/β‐actin optical density ratio was significantly higher in the ALS group as compared to the control group. Next, we conducted cell culture experiments using a human astrocytoma‐derived cell line (1321N1) and a mouse motor neuron/neuroblastoma hybrid cell line (NSC34). In 1321N1 cells, the normalized xCT expression levels in cell lysates were significantly increased by H2O2treatment. Glutamate concentrations in 1321 N1 cell culture‐conditioned media were significantly elevated by H2O2treatment, and the H2O2‐driven elevations were completely canceled by the xCT inhibitor erastin pretreatment. In motor neuron‐differentiated NSC34 cells (NSC34d cells), both the normalized xCT expression levels in the cell lysates and glutamate concentrations in the cell‐conditioned media were constant with or without H2O2treatment. The present results providein vivoandin vitroevidence that astrocytes upregulate xCT expression to release glutamate in response to increased oxidative stress associated with ALS, contributing to extracellular glutamate accumulation.