3,4-Dihydroxyphenylacetaldehyde-Induced Protein Modifications and Their Mitigation by N-Acetylcysteine
3,4-Dihydroxyphenylacetaldehyde-Induced Protein Modifications and Their Mitigation by N-Acetylcysteine
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DOI：
10.1124/jpet.118.248492
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发表时间：
2018-07-01
影响因子：
3.5
通讯作者：
Goldstein, David S.
中科院分区：
文献类型：
--
作者：
Jinsmaa, Yunden;Sharabi, Yehonatan;Goldstein, David S.
儿茶酚醛假说认为，3,4-二羟基苯乙醛（DOPAL）是多巴胺的一种专性中间代谢产物，是一种自毒素，会挑战儿茶酚胺能神经元的神经元稳态。 DOPAL 毒性可能涉及蛋白质修饰，例如 α-突触核蛋白 (AS) 的寡聚化。然而，DOPAL 和其他与儿茶酚胺能神经变性相关的蛋白质之间的潜在相互作用尚未得到系统探索。本研究在培养的 MO3.13 人少突胶质细胞和 PC12 大鼠嗜铬细胞瘤细胞以及试管实验中检查了 DOPAL 诱导的蛋白质-醌加合物形成（“醌化”）以及蛋白质寡聚化、泛素化和聚集。使用近红外荧光光谱，我们检测到 DOPAL 自发氧化为 DOPAL-醌，DOPAL 诱导两种细胞系中细胞内蛋白质的醌化，以及 DOPAL 诱导的与儿茶酚胺能神经变性相关的几种蛋白质的醌化，包括 AS、2 型囊泡单胺转运蛋白、葡萄糖脑苷脂酶、泛素和 L-芳香氨基酸脱羧酶（拉阿德）。 DOPAL 还寡聚了 AS、泛素和 LAAAD；灭活的 LAAAD (IC50 54 mu M)；引起大量细胞内蛋白质泛素化；和聚集的细胞内AS。值得注意的是，N-乙酰半胱氨酸可减少 DOPAL-醌的形成，从而减弱或阻止所有这些蛋白质修饰和功能变化。该结果符合以下观点：基于减少 DOPAL 形成和氧化的治疗可能会减缓或预防儿茶酚胺能神经变性。
The catecholaldehyde hypothesis posits that 3,4-dihydroxyphe-nylacetaldehyde (DOPAL), an obligate intermediary metabolite of dopamine, is an autotoxin that challenges neuronal homeo-stasis in catecholaminergic neurons. DOPAL toxicity may involve protein modifications, such as oligomerization of a-synuclein (AS). Potential interactions between DOPAL and other proteins related to catecholaminergic neurodegeneration, however, have not been systemically explored. This study examined DOPAL-induced protein-quinone adduct formation ("quinonization") and protein oligomerization, ubiquitination, and aggregation in cultured MO3.13 human oligodendrocytes and PC12 rat pheochromocytoma cells and in test tube experiments. Using near-infrared fluorescence spectroscopy, we detected spontaneous DOPAL oxidation to DOPAL-quinone, DOPAL-induced quinonization of intracellular proteins in both cell lines, and DOPAL-induced quinonization of several proteins related to catecholaminergic neurodegeneration, including AS, the type 2 vesicular monoamine transporter, glucocerebrosidase, ubiquitin, and L-aromatic-amino-acid decarboxylase (LAAAD). DOPAL also oligomerized AS, ubiquitin, and LAAAD; inactivated LAAAD (IC50 54 mu M); evoked substantial intracellular protein ubiquitination; and aggregated intracellular AS. Remarkably, N-acetylcysteine, which decreases DOPAL-quinone formation, attenuated or prevented all of these protein modifications and functional changes. The results fit with the proposal that treatments based on decreasing the formation and oxidation of DOPAL may slow or prevent catecholaminergic neurodegeneration.