Function of alphaB-crystallin in brain development and neurodegeneration

αB-晶状体蛋白在大脑发育和神经退行性变中的功能

基本信息

批准号：
06454694
负责人：
IWAKI Toru
金额：
$ 3.58万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

It has been shown by immunohistochemical studies that alphaB-crystallin accumulated in the reactive and neoplastic glial cells in a variety of pathologic situations. We investigated the phenotypic effects of selectively altering the levels of alphaB-crystallin in cultured glial cells by genetic manipulation. Glioma cells were transfected with a rat alphaB-crystallin sense cDNA or an antisense cDNA to alter cellular levels of alphaB-crystallin. The anti-sense strategy resulted in decreased alphaB-crystallin levels, as revealed by Western blot and immunocytochemical analyzes. The reduced alphaBj-crystallin expression was accompanied by alterations in cellular phenotyp :(1)a reduction of cell size and/or a slender cell mophology ; (2)a disorganized microfilament network ; and (3)a reduction of cell adhesiveness. Like HSP27, the presence of additional alphaB-crystallin protein confer a thermoresistant phenotype to stable transfectants. Thus, alphaB-crystallin inglioma cells plays a role in their thermal resistance and maycontribute to the stability of cytoskeletal organization. Next we investigated the influence of elevated extracellular K^+ on th expression of alphaB-crystallin in glial cells. The treatment of the glioma cells with augmented K^+ in the cultrue media induced an accumulation of alphaB-crystallin mRNA in a dose-dependent manner and an accumulation of the alphaB-crystallin as well. Furthermore, an overexpression of alphaB-crystallin in the transformant transfected with a rat alphaB-crystallin cDNA conferred a resistant phenotype against the insult of elevated extracellular K^+ on the glioma cells. Thus, alphaB-crystallin may contribute to the survival of reactive glia in the presence of a high extracellular K^+ concentration.

免疫组织化学研究表明，在多种病理状况中，字母晶状体晶状体积聚在反应性和肿瘤神经胶质细胞中。我们通过遗传操纵研究了在培养的神经胶质细胞中选择性改变α-晶状体蛋白水平的表型效应。用大鼠字母 - 晶状体塞蛋白cDNA或反义cDNA转染神经胶质瘤细胞，以改变α-晶状体蛋白的细胞水平。如Western印迹和免疫细胞化学分析所揭示的那样，反义策略导致字母结晶蛋白水平降低。降低的Alphabj-晶状蛋白表达伴随着细胞表型的改变：（1）细胞大小和/或细细胞蒙面的降低；（2）混乱的微丝网络；（3）细胞粘附性的降低。像HSP27一样，其他字母晶状体结晶蛋白的存在将热固抗表型赋予稳定转染物。因此，α-晶状体结构性瘤细胞在其热耐药性中起作用，并可能对细胞骨架组织的稳定性作用。接下来，我们研究了升高的细胞外K^+对神经胶质细胞中α-晶状体的Th表达的影响。在限化培养基中，用增强的K^+对神经胶质瘤细胞的处理诱导了阿尔相 - 晶状体mRNA的积累，并以剂量依赖性的方式和α-晶状体晶体蛋白的积累。此外，用大鼠阿尔相晶蛋白cDNA转染的α-晶状体蛋白的过表达赋予对胶质瘤细胞上升高的细胞外K^+的耐药表型。因此，在高细胞外K^+浓度存在下，字母晶状体可能有助于反应性神经胶质的存活。