Kamphuis Willem, Kooijman Lieneke, Orre Marie, Stassen Oscar, Pekny Milos, Hol Elly M
Astrocyte Biology & Neurodegeneration, Netherlands Institute for Neuroscience (NIN), An Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands; Synaptic Plasticity & Behavior, Netherlands Institute for Neuroscience (NIN), Amsterdam, The Netherlands.
Glia. 2015 Jun;63(6):1036-56. doi: 10.1002/glia.22800. Epub 2015 Mar 2.
Reactive astrocytes with an increased expression of intermediate filament (IF) proteins Glial Fibrillary Acidic Protein (GFAP) and Vimentin (VIM) surround amyloid plaques in Alzheimer's disease (AD). The functional consequences of this upregulation are unclear. To identify molecular pathways coupled to IF regulation in reactive astrocytes, and to study the interaction with microglia, we examined WT and APPswe/PS1dE9 (AD) mice lacking either GFAP, or both VIM and GFAP, and determined the transcriptome of cortical astrocytes and microglia from 15- to 18-month-old mice. Genes involved in lysosomal degradation (including several cathepsins) and in inflammatory response (including Cxcl5, Tlr6, Tnf, Il1b) exhibited a higher AD-induced increase when GFAP, or VIM and GFAP, were absent. The expression of Aqp4 and Gja1 displayed the same pattern. The downregulation of neuronal support genes in astrocytes from AD mice was absent in GFAP/VIM null mice. In contrast, the absence of IFs did not affect the transcriptional alterations induced by AD in microglia, nor was the cortical plaque load altered. Visualizing astrocyte morphology in GFAP-eGFP mice showed no clear structural differences in GFAP/VIM null mice, but did show diminished interaction of astrocyte processes with plaques. Microglial proliferation increased similarly in all AD groups. In conclusion, absence of GFAP, or both GFAP and VIM, alters AD-induced changes in gene expression profile of astrocytes, showing a compensation of the decrease of neuronal support genes and a trend for a slightly higher inflammatory expression profile. However, this has no consequences for the development of plaque load, microglial proliferation, or microglial activation.
在阿尔茨海默病(AD)中,中间丝(IF)蛋白胶质纤维酸性蛋白(GFAP)和波形蛋白(VIM)表达增加的反应性星形胶质细胞围绕着淀粉样斑块。这种上调的功能后果尚不清楚。为了确定与反应性星形胶质细胞中IF调节相关的分子途径,并研究与小胶质细胞的相互作用,我们检查了缺乏GFAP或同时缺乏VIM和GFAP的野生型(WT)和APPswe/PS1dE9(AD)小鼠,并测定了15至18月龄小鼠皮质星形胶质细胞和小胶质细胞的转录组。当缺乏GFAP或VIM和GFAP时,参与溶酶体降解(包括几种组织蛋白酶)和炎症反应(包括Cxcl5、Tlr6、Tnf、Il1b)的基因在AD诱导下表现出更高的增加。水通道蛋白4(Aqp4)和缝隙连接蛋白α1(Gja1)的表达呈现相同模式。在GFAP/VIM基因敲除小鼠中,AD小鼠星形胶质细胞中神经元支持基因的下调不存在。相反,IF的缺失并不影响AD诱导的小胶质细胞转录改变,皮质斑块负荷也未改变。在GFAP-eGFP小鼠中观察星形胶质细胞形态,发现GFAP/VIM基因敲除小鼠没有明显的结构差异,但确实显示星形胶质细胞突起与斑块的相互作用减少。所有AD组中小胶质细胞增殖均有类似增加。总之,缺乏GFAP或同时缺乏GFAP和VIM会改变AD诱导的星形胶质细胞基因表达谱变化,显示出对神经元支持基因减少的补偿以及炎症表达谱略高的趋势。然而,这对斑块负荷的发展、小胶质细胞增殖或小胶质细胞激活没有影响。