6-hydroxydopamine increases ubiquitin-conjugates and protein degradation: Implications for the pathogenesis of Parkinson's disease
6-hydroxydopamine increases ubiquitin-conjugates and protein degradation: Implications for the pathogenesis of Parkinson's disease
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DOI：
10.1023/a:1015160323009
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发表时间：
2001-12-01
影响因子：
4
通讯作者：
Offen, D
中科院分区：
文献类型：
--
作者：
Elkon, H;Melamed, E;Offen, D
帕金森病 (PD) 的标志之一是病理结构，称为路易体，在黑质的多巴胺能神经元中含有泛素化蛋白的内含物。尽管已经证明α-突触核蛋白或泛素相关酶UCH-L1的突变可能会诱导这种蛋白质聚集，但导致这些聚集体形成的机制尚不清楚。因此，我们研究了 6-羟基多巴胺 (6-OHDA)（一种用于 PD 实验模型的多巴胺能神经毒素）在引起蛋白质降解中的可能作用及其与泛素系统的关联。使用抗泛素抗体，我们发现 SH-SY5Y 神经母细胞瘤和 PC-12 细胞系暴露于 6-OHDA 会以剂量依赖性方式增加游离泛素和泛素缀合蛋白的水平。此外，35S-蛋氨酸的代谢标记表明，6-OHDA 显着增加了蛋白质降解，正如蛋白质代谢物分泌到培养基中所表明的那样。特异性抑制剂 MG132 抑制蛋白酶体活性，减弱 6-OHDA 诱导的蛋白质降解并增强其毒性。将抗氧化剂 N-乙酰半胱氨酸给予 6-OHDA 处理的细胞，可以增加细胞存活率并减少蛋白质降解。总之，我们的发现；表明 6-OHDA 毒性与蛋白质降解和泛素-蛋白酶体系统激活有关。
One of the hallmarks of Parkinson's disease (PD) is pathological structure, termed Lewy body, containing inclusions of ubiquitinated proteins in the dopaminergic neurons in the substantia nigra. The mechanism leading to the formation of these aggregates is unclear, although it has been shown that mutations in alpha-synuclein or in the ubiquitin-related enzyme UCH-L1 might induce such protein aggregation. We, therefore, examined the possible role of 6-hydroxydopamine (6-OHDA), a dopaminergic neurotoxin used in PD experimental models, in causing protein degradation and its association with the ubiquitin system. Using antiubiquitin antibodies we found that exposure of SH-SY5Y neuroblastoma and PC-12 cell lines to 6-OHDA increased the levels of free ubiquitin and ubiquitin-conjugated proteins, in a dose-dependent manner. Furthermore, metabolic labeling with 35S-methionine, demonstrated that 6-OHDA markedly increased protein degradation, as indicated by the secretion of protein metabolites to the medium. Inhibition of the proteasome activity by the specific inhibitor MG132, attenuated the protein degradation induced by 6-OHDA and potentiated its toxicity. Administration of the antioxidant N-acetyleysteine to the 6-OHDA-treated cells, increased cell survival and reduced protein degradation. In conclusion, our finding,; suggest that 6-OHDA toxicity is associated with protein degradation and ubiquitin-proteasome system activation.