Modulation of glial glutamate transport through cell interactions with the extracellular matrix
Modulation of glial glutamate transport through cell interactions with the extracellular matrix
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DOI：
10.1016/s0736-5748(02)00048-5
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发表时间：
2002-06-01
影响因子：
1.8
通讯作者：
Sontheimer, H
中科院分区：
文献类型：
--
作者：
Ye, ZC;Sontheimer, H
胶质细胞谷氨酸转运在维持中枢神经系统谷氨酸稳态中发挥着关键作用。谷氨酸转运蛋白的表达在大脑发育过程中受到高度调节，许多病理状况与谷氨酸转运蛋白的表达和/或功能缺陷有关。虽然多种可溶性因子已被证明可以调节谷氨酸转运蛋白的表达，但细胞-细胞相互作用和细胞-环境相互作用在谷氨酸转运调节中的作用尚不清楚。细胞外基质 (ECM) 分子是细胞与细胞以及细胞与环境相互作用的重要组成部分，ECM 已被证明在正常发育和大脑发病机制中发挥着关键作用。因此，我们研究了 ECM 分子调节星形胶质细胞谷氨酸转运的可能性。因此，我们用不同的ECM培养大鼠皮质星形胶质细胞，并通过Western Blot测定两种星形胶质细胞谷氨酸转运蛋白GLT-1和GLAST的表达水平，并通过测量H-3-D-天冬氨酸摄取来确定转运蛋白活性。在聚鸟氨酸或多聚-D/L-赖氨酸上生长的星形胶质细胞显示出的 GLT-1 表达比在没有 ECM 的塑料培养皿上生长的姐妹细胞高大约两倍。天然存在的 ECM，包括层粘连蛋白和胶原蛋白，显示出 GLT-1 蛋白表达的剂量依赖性调节。这些效应是 GLT-1 特异的，因为 GLAST 表达不受不同 ECM 的影响。然而，令人惊讶的是，所检查的 ECM 均未改变表观谷氨酸摄取活性。在并排检测 Na+/K+-ATPase 表达的印迹中，我们发现 ECM 以相互方式影响 Na+/K+-ATPase 和 GLT-1 的表达。例如，聚鸟氨酸可以增强 GLT-1 表达，但降低 Na+/K+-ATP 酶的表达。因此，Na+转运可能是谷氨酸吸收的限制因素。 (C) 2002 ISDN。由爱思唯尔科学有限公司出版。保留所有权利。
Glial glutamate transport plays a pivotal role in maintaining glutamate homeostasis in the central nervous system. Expression of glutamate transporters is highly regulated during brain development, and a number of pathological conditions are associated with deficits in expression and/or function of glutamate transports. While several soluble factors have been shown to regulate the expression of glutamate transporter, the contribution of cell-cell interaction and cell-environmental interaction in the regulation of glutamate transport is unknown. Extracellular matrix (ECM) molecules are essential components in cell-cell and cell-environmental interactions, and the ECM has been shown to play critical role in normal development and during brain pathogenesis. We, therefore, investigated the possibility that ECM molecules may regulate astrocytic glutamate transport. Therefore, we cultured rat cortical astrocytes with different ECMs and determined expression levels of the two astrocytic glutamate transporters GLT-1 and GLAST by Western Blot and determined transporter activity through measurements of H-3-D-aspartate uptake. Astrocytes grown on poly-ornithine or poly-D/L-lysine showed approximately two-fold higher GLT-1 expression than sister cells grown on plastic dishes without ECM. Naturally occurring ECM's, including laminin and collagen, showed a dose-dependent regulation of GLT-1 protein expression. These effects were specific for GLT-1 as GLAST expression was unaffected by different ECMs. Surprisingly, however, none of the examined ECMs altered the apparent glutamate uptake activity. In probing blots side-by-side for expression of Na+/K+-ATPase, we found that ECMs affected expression of Na+/K+-ATPase and GLT-1 in a reciprocal fashion. Poly-ornithine, for example, enhanced GLT-1 expression, but reduced expression of Na+/K+-ATPase. Na+ transport may, thus, be a limiting factor for glutamate uptake. (C) 2002 ISDN. Published by Elsevier Science Ltd. All rights reserved.