Prion protein fragment 106-126 induces a p38 MAP kinase-dependent apoptosis in SH-SY5Y neuroblastoma cells independently from the amyloid fibril formation
Prion protein fragment 106-126 induces a p38 MAP kinase-dependent apoptosis in SH-SY5Y neuroblastoma cells independently from the amyloid fibril formation
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DOI：
10.1196/annals.1299.114
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发表时间：
2003-01-01
期刊：
影响因子：
--
通讯作者：
Florio, T
中科院分区：
文献类型：
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作者：
Corsaro, A;Thellung, S;Florio, T
朊病毒疾病是人和动物中枢神经系统的神经退行性疾病，其特征在于中枢神经系统的海绵状变性、星形胶质细胞增生和淀粉样蛋白沉积到脑中。细胞糖蛋白（朊病毒蛋白，PrPC）转化为改变的同种型（PrPSc）已被认为是这些疾病的致病事件。PrP序列第106 - 126位残基所对应的肽段（PrP 106 -126）被广泛应用于朊病毒疾病神经毒性机制的研究。我们研究了SH-SY 5 Y人神经母细胞瘤细胞系中负责PrP 106 -126依赖性细胞死亡的细胞内信号传导。在这些细胞中，PrP 106 -126处理诱导凋亡性细胞死亡和caspase-3的激活。p38 MAP-激酶阻断剂（SB 203580和PD 169316）防止由PrP 106 -126诱发的凋亡性细胞死亡，并且Western印迹分析显示细胞暴露于肽诱导p38活化。然而，PrP 106 -126的神经元毒性是否由该肽的可溶性或纤维状形式引起仍然未知。在这项研究中，我们将这种肽的结构状态与其神经毒性相关联。我们发现，两个保守的甘氨酸在位置114和119防止肽采取结构化的构象，有利于其聚集在淀粉样纤维。用丙氨酸残基（PrP 106 - 126 AA）取代两个甘氨酸产生可溶性非淀粉样蛋白生成肽，当与神经母细胞瘤细胞孵育时，其保留其毒性特性。这些数据表明，淀粉样蛋白聚集不是诱导PrP 106 -126毒性作用所必需的。
Prion diseases are neurodegenerative disorders of the central nervous system of humans and animals, characterized by spongiform degeneration of the central nervous system, astrogliosis, and deposition of amyloid into the brain. The conversion of a cellular glycoprotein (prion protein, PrPC) into an altered isoform (PrPSc) has been proposed to represent the causative event responsible for these diseases. The peptide corresponding to the residues 106126 of PrP sequence (PrP106-126) is largely used to explore the neurotoxic mechanisms underlying the prion diseases. We investigated the intracellular signaling responsible for PrP106-126-dependent cell death in the SH-SY5Y human neuroblastoma cell line. In these cells, PrP106-126 treatment induced apoptotic cell death and the activation of caspase-3. The p38 MAP-kinase blockers (SB203580 and PD169316) prevented the apoptotic cell death evoked by PrP106-126 and Western blot analysis revealed that the exposure of the cells to the peptide induced p38 activation. However, whether the neuronal toxicity of PrP106-126 is caused by a soluble or fibrillar form of this peptide is still unknown. In this study, we correlated the structural state of this peptide with its neurotoxicity. We show that the two conserved glycines in position 114 and 119 prevent the peptide to assume a structured conformation, favoring its aggregation in amyloid fibrils. The substitution of both glycines with alanine residues (PrP106-126AA) generates a soluble nonamyloidogenic peptide, that retained its toxic properties when incubated with neuroblastoma cells. These data show that the amyloid aggregation is not necessary for the induction of the toxic effects of PrP106-126.