Clusterin (SGP-2) induction in rat astroglial cells exposed to prion protein fragment 106-126
Clusterin (SGP-2) induction in rat astroglial cells exposed to prion protein fragment 106-126
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DOI：
10.1111/j.1460-9568.1996.tb01244.x
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发表时间：
1996-03-01
影响因子：
3.4
通讯作者：
Forloni, G
中科院分区：
文献类型：
--
作者：
Chiesa, R;Angeretti, N;Forloni, G
Prion相关脑病的特征是异常的Prion蛋白亚型(PrPSc)积聚，与神经元变性和星形胶质细胞增生有关。与PrP 106-126片段同源的合成肽(PrP 106-126)在体外诱导神经细胞凋亡和胶质细胞增殖。我们使用Northern印迹分析和RNA聚合酶链式反应来评估与细胞程序性死亡和增殖相关的几个基因的表达。提取神经细胞和星形胶质细胞总RNA，经PrP106-126作用1h~7d后，与识别c-fos、c-jun、c-myc、p53、HSP-70和bcl2mRNA的探针杂交。除神经细胞bcl2mRNA略有下降外，其他转录本均无明显变化。由于Prion相关脑病中Clusterin(载脂蛋白J)的mRNA水平升高，并且Clusterin免疫反应与PrPSc在Gerstmann-Straussler-Scheinker脑中被定位，因此我们确定了长期暴露于PrP 106-126的神经细胞和星形胶质细胞中Clusterin的表达。虽然在其他实验条件下，Clusterin的诱导也参与了细胞凋亡的机制，但在PrP 106-126处理的神经元中，其表达没有变化，而在暴露于PrP 106-126的星形胶质细胞中，观察到Clusterin mRNA的诱导是原来的三倍。为了研究聚集素的上调是与PrP 106-126的星形胶质细胞增殖刺激有关，还是被该肽特异性地诱导，我们检测了在无血清培养的星形胶质细胞和暴露于PrP 106-126或胎牛血清修复的星形胶质细胞中的Clusterin的表达。在此条件下，PrP多肽和胎牛血清一样能促进神经胶质细胞的增殖率，但只有PrP 106-126使Clusterin mRNA增加了一倍。这种效应的选择性表明PrPSc直接参与了蛋白相关脑病中的聚集素上调，并与星形胶质细胞有关。
Prion-related encephalopathies are characterized by the accumulation of an abnormal prion protein isoform (PrPSc) associated with neuronal degeneration and astrogliosis. The synthetic peptide homologous to PrP fragment 106-126 (PrP 106-126) induced in vitro neuronal apoptosis and glial proliferation. We used Northern blot analysis and the RNA polymerase chain reaction to assess the expression of several genes associated with programmed cell death and proliferation. Blots of total RNA extracted from neuronal and astroglial cells exposed to PrP 106-126 for between 1 h and 7 days were hybridized with probes recognizing c-fos, c-jun, c-myc, p53, hsp-70 and bcl-2 mRNA. Except for a slight decrease in bcl-2 mRNA in neuronal cells, no change in other transcripts was evident. Since clusterin (apolipoprotein J) mRNA levels are increased in prion-related encephalopathies and clusterin immunoreactivity has been located in association with PrPSc in Gerstmann-Straussler-Scheinker brain, the expression of clusterin was determined in neuronal and astroglial cells chronically exposed to PrP 106-126. Although the induction of clusterin has been involved in the apoptotic mechanism in other experimental conditions, its expression was unchanged in PrP 106-126-treated neurons, while a three-fold induction of clusterin mRNA was observed in astrocytes exposed to PrP 106-126. To investigate whether the clusterin up-regulation was simply associated with the astroglial proliferative stimulus of PrP 106-126 or was specifically induced by the peptide, we measured clusterin expression in astrocytes cultured in fetal calf serum-free medium and exposed to PrP 106-126 or fetal calf serum restoration. In this condition the PrP peptide, like fetal calf serum, increased the glial proliferation rate, but only PrP 106-126 doubled clusterin mRNA. The selectivity of this effect indicates that PrPSc is directly involved in the clusterin upregulation seen in prion-related encephalopathies and is associated with astroglial cells.