Prasad Judith E, Kumar Bipin, Andreatta Cynthia, Nahreini Piruz, Hanson Amy J, Yan Xiang Dong, Prasad Kedar N
Center for Vitamins and Cancer Research, Department of Radiology, School of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
J Neurosci Res. 2004 May 1;76(3):415-22. doi: 10.1002/jnr.20058.
Increased accumulation of alpha-synuclein is associated with certain neurodegenerative diseases including Parkinson's disease (PD) and Alzheimer's disease (AD). One mechanism of alpha-synuclein-induced toxicity involves increased oxidative stress. It was unknown whether neurons overexpressing alpha-synuclein would exhibit increased sensitivity to hydrogen peroxide (H(2)O(2)) or 3-morpholinosydnonimine (SIN-1; a nitrous oxide donor). To study this, we developed a murine neuroblastoma (NB) cell line that overexpresses wild-type human alpha-synuclein (NBP2-PN54) under the control of the cytomegalovirus (CMV) promoter using a retroviral vector. Human alpha-synuclein mRNA and protein were readily detectable in NBP2-PN54 cells. Results showed that differentiated NBP2-PN54 cells exhibited decreased viability in comparison to differentiated vector (NBP2-PN1) and parent (NBP2) control cells. These cells also exhibited increased sensitivity to PGE(2), H(2)O(2) and SIN-1. Because of involvement of proteasome inhibition in neurodegeneration, we also investigated whether treatment of differentiated NBP2-PN54 cells with PGE(2), H(2)O(2) or SIN-1 inhibits proteasome activity. Results showed that H(2)O(2) and SIN-1 inhibited proteasome activity, but PGE(2) did not. These results suggest that overexpression of alpha-synuclein not only participates directly in degeneration of neurons, but it also increases the vulnerability of neurons to other potential neurotoxins.
α-突触核蛋白的积累增加与某些神经退行性疾病有关，包括帕金森病（PD）和阿尔茨海默病（AD）。α-突触核蛋白诱导毒性的一种机制涉及氧化应激增加。尚不清楚过表达α-突触核蛋白的神经元是否对过氧化氢（H₂O₂）或3-吗啉代-sydnonimine（SIN-1；一种一氧化氮供体）表现出更高的敏感性。为了研究这一点，我们使用逆转录病毒载体，开发了一种在巨细胞病毒（CMV）启动子控制下过表达野生型人α-突触核蛋白的小鼠神经母细胞瘤（NB）细胞系（NBP2-PN54）。在NBP2-PN54细胞中很容易检测到人α-突触核蛋白的mRNA和蛋白质。结果表明，与分化的载体（NBP2-PN1）和亲本（NBP2）对照细胞相比，分化的NBP2-PN54细胞活力降低。这些细胞对前列腺素E₂（PGE₂）、H₂O₂和SIN-1也表现出更高的敏感性。由于蛋白酶体抑制参与神经退行性变，我们还研究了用PGE₂、H₂O₂或SIN-1处理分化的NBP2-PN54细胞是否会抑制蛋白酶体活性。结果表明，H₂O₂和SIN-1抑制蛋白酶体活性，但PGE₂没有。这些结果表明，α-突触核蛋白的过表达不仅直接参与神经元的变性，还增加了神经元对其他潜在神经毒素的易感性。
