Changes in protein structure and distribution observed at pre-clinical stages of scrapie pathogenesis
Changes in protein structure and distribution observed at pre-clinical stages of scrapie pathogenesis
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DOI：
10.1016/j.bbadis.2008.06.004
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发表时间：
2008-10-01
影响因子：
6.2
通讯作者：
Miller, Lisa M.
中科院分区：
文献类型：
--
作者：
Kretlow, Ariane;Wang, Qi;Miller, Lisa M.
痒病是一种神经退行性疾病，涉及朊病毒蛋白 (PrP) 的错误折叠、聚集和积累。正常细胞 PrP (PrPc) 富含 α 螺旋二级结构，而与疾病相关的致病形式的蛋白质 (PrPSc) 则具有异常高的 β 折叠含量。在这项研究中，使用同步加速器傅里叶变换红外显微光谱 (FTIRM) 在疾病过程中的四个时间点（临床前、感染后 100 和 130 天 (dpi)）对经口 263K 痒病感染和模拟感染仓鼠的背根神经节中的蛋白质结构变化进行了原位检查；首次临床症状（类似于 145 dpi）；和终端（类似于 170 dpi））。结果显示，随着疾病的进展，总蛋白含量、结构和分布发生了明显的变化。在临床前时间点，感染痒病的动物表现出蛋白质表达显着增加，但β-折叠蛋白含量显着低于对照组。基于这些发现，我们认为痒病的临床前阶段的特征是β-片层含量低的蛋白质过度表达。随着病情进展，1片含量显着增加。使用 PrP 特异性抗体 3F4 进行的免疫染色证实，这种增加部分但不仅仅是由于组织中 PrPSc 的形成，并表明通过过度表达或错误折叠产生了其他富含 β-折叠的蛋白质。在临床前时间点，在细胞膜附近观察到β-折叠升高，在感染后期，在受感染神经元的细胞质中也观察到β-折叠升高。在疾病的末期，蛋白质表达显着下降，可能是由于神经元变性和死亡。蛋白质含量和结构的这些巨大变化，尤其是在临床前时间点，强调了识别参与早期发病机制的其他蛋白质的可能性，这对于进一步了解该疾病非常重要。 (C) 2008 Elsevier B.V. 保留所有权利。
Scrapie is a neurodegenerative disorder that involves the misfolding, aggregation and accumulation of the prion protein (PrP). The normal cellular PrP (PrPc) is rich in alpha-helical secondary structure, whereas the disease-associated pathogenic form of the protein (PrPSc) has an anomalously high beta-sheet content. in this study, protein structural changes were examined in situ in the dorsal root ganglia from perorally 263K scrapie-infected and mock-infected hamsters using synchrotron Fourier Transform InfraRed Microspectroscopy (FTIRM) at four time points over the course of the disease (pre-clinical, 100 and 130 days post-infection (dpi); first clinical signs (similar to 145 dpi); and terminal (similar to 170 dpi)). Results showed clear changes in the total protein content, structure, and distribution as the disease progressed. At pre-clinical time points, the scrapie-infected animals exhibited a significant increase in protein expression, but the beta-sheet protein content was significantly lower than controls. Based on these findings, we suggest that the pre-clinical stages of scrapie are characterized by an overexpression of proteins low in beta-sheet content. As the disease progressed, the 1 sheet content increased significantly. Immunostaining with a PrP-specific antibody, 3F4, confirmed that this increase was partly - but not solely - due to the formation of PrPSc in the tissue and indicated that other proteins high in beta-sheet were produced, either by overexpression or misfolding. Elevated beta-sheet was observed near the cell membrane at pre-clinical time points and also in the cytoplasm of infected neurons at later stages of infection. At the terminal stage of the disease, the protein expression declined significantly, likely due to degeneration and death of neurons. These dramatic changes in protein content and structure, especially at pre-clinical time points, emphasize the possibility for identifying other proteins involved in early pathogenesis, which are important for a further understanding of the disease. (C) 2008 Elsevier B.V. All rights reserved.