Loss of glial fibrillary acidic protein results in decreased glutamate transport and inhibition of PKA-induced EAAT2 cell surface trafficking
Loss of glial fibrillary acidic protein results in decreased glutamate transport and inhibition of PKA-induced EAAT2 cell surface trafficking
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DOI：
10.1016/j.molbrainres.2004.02.021
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发表时间：
2004-05-19
期刊：
影响因子：
--
通讯作者：
Sutherland, ML
中科院分区：
文献类型：
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作者：
Hughes, EG;Maguire, JL;Sutherland, ML
星形胶质细胞特有的中间丝蛋白-胶质纤维酸性蛋白(GFAP)的缺失导致对缺血性损伤的易感性增加，海马LTP增强，小脑长期抑郁(LTD)减少。由于谷氨酸受体激活在细胞死亡和细胞可塑性反应中起关键作用，我们想要确定胶质细胞谷氨酸运输的变化是否会导致GFAP缺失表型。为了解决谷氨酸转运的功能变化，我们测量了年龄匹配的成年野生型和GFAP缺失型小鼠大脑皮质、小脑和海马突触体的谷氨酸摄取，结果显示GFAP缺失型动物大脑皮质和海马区D-天冬氨酸摄取的V-max降低了25%-30%。对野生型和GFAP缺失动物皮质突触体组分的Western印迹分析表明，GFAP的缺失导致星形胶质细胞(EAAT 1)和神经元(EAAT3)谷氨酸转运体亚型的减少。免疫组织化学分析显示神经元谷氨酸转运体的区域特异性修饰，EAAT3在GFAP缺失表型中运输。对GFAP缺失和野生型小鼠的原代皮质星形胶质细胞培养的分析表明，GFAP的缺失导致在二丁酰cAMP刺激蛋白激酶A(PKA)后，胶质谷氨酸转运体EAAT2无法运输到细胞表面。综上所述，这些结果提示，中间丝蛋白GFAP在调节星形胶质细胞和神经元谷氨酸转运体的运输和功能中起着关键作用。(C)2004爱思唯尔B.V.保留所有权利。
Loss of the astrocyte-specific intermediate filament protein, glial fibrillary acidic protein (GFAP) results in an increased susceptibility to ischemic insult, enhanced hippocampal LTP, and decreased cerebellar long-term depression (LTD). Because glutamate receptor activation plays a key role in cell death and cellular plasticity responses, we wanted to determine if alterations in glial glutamate transport could contribute to the GFAP null phenotype. To address functional changes in glutamate transport, we measured glutamate uptake in cortical, cerebellar, and hippocampal synaptosomal preparations from age-matched adult wild type and GFAP null mice and demonstrated a 25 -30% reduction in the V-max for D-aspartate uptake in the cortex and hippocampus of GFAP null animals. Western blot analysis of cortical synaptosomal fractions from wild type and GFAP null animals demonstrated that loss of GFAP results in decreases in both astrocytic (EAAT 1) and neuronal (EAAT3) glutamate transporter subtypes. Immunohistochemical analysis demonstrated a region-specific modification of neuronal glutamate transporter, EAAT3 trafficking in the GFAP null phenotype. Analysis of primary cortical astrocyte cultures prepared from GFAP null and wild type mice demonstrated that loss of GFAP results in an inability to traffic the glial glutamate transporter, EAAT2, to the surface of the cell following protein kinase A (PKA) stimulation by dibutyryl cAMP. Taken together, these results suggest that the intermediate filament protein, GFAP plays a key role in modulating astrocytic and neuronal glutamate transporter trafficking and function. (C) 2004 Elsevier B.V. All rights reserved.