Proteasome inhibition and aggregation in Parkinson's disease: a comparative study in untransfected and transfected cells
Proteasome inhibition and aggregation in Parkinson's disease: a comparative study in untransfected and transfected cells
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DOI：
10.1046/j.1471-4159.2003.02152.x
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发表时间：
2004-02-01
影响因子：
4.7
通讯作者：
Forloni, G
中科院分区：
文献类型：
--
作者：
Biasini, E;Fioriti, L;Forloni, G
泛素-蛋白酶体系统（UPS）的功能障碍与帕金森病（PD）和其他神经退行性疾病有关。我们研究了UPS抑制α -突触核蛋白（SYN）和帕金蛋白代谢的影响，这两种蛋白在遗传和组织病理学上都与PD相关。蛋白酶体的药理抑制诱导转染PC12细胞中parkin和SYN的积累。我们发现这种效应是由蛋白质合成增加而不是蛋白质降解受损引起的，这表明抑制UPS可能导致巨细胞病毒（CMV）驱动的转录的非特异性上调。为了研究内源性parkin和SYN是否可以作为UPS的底物，我们将未转染的PC12细胞和原代中脑神经元暴露于蛋白酶体抑制剂中，并在蛋白和mRNA水平上评估parkin和SYN的表达。在这些条件下，我们发现蛋白酶体抑制剂不影响内源性parkin和SYN的水平，但我们证实了多巴胺能神经元对蛋白酶体抑制剂的毒性具有选择性易感性。我们的研究结果表明，涉及使用蛋白酶体抑制剂的研究，特别是那些从异源启动子表达蛋白质的研究，在解释UPS在PD发病机制中的作用时，需要考虑潜在的伪象。
Dysfunction of the ubiquitin-proteasome system (UPS) has been implicated in Parkinson's disease (PD) and other neurodegenerative disorders. We have investigated the effect of UPS inhibition on the metabolism of alpha-synuclein (SYN) and parkin, two proteins genetically and histopathologically associated to PD. Pharmacological inhibition of proteasome induced accumulation of both parkin and SYN in transfected PC12 cells. We found that this effect was caused by increased protein synthesis rather than impairment of protein degradation, suggesting that inhibition of the UPS might lead to non-specific up-regulation of cytomegalovirus (CMV)-driven transcription. To investigate whether endogenous parkin and SYN can be substrate of the UPS, untransfected PC12 cells and primary mesencephalic neurones were exposed to proteasome inhibitors, and parkin and SYN expression was evaluated at both protein and mRNA level. Under these conditions, we found that proteasome inhibitors did not affect the level of endogenous parkin and SYN. However, we confirmed that dopaminergic neurones were selectively vulnerable to the toxicity of proteasome inhibitors. Our results indicate that studies involving the use of proteasome inhibitors, particularly those in which proteins are expressed from a heterologous promoter, are subjected to potential artefacts that need to be considered for the interpretation of the role of UPS in PD pathogenesis.