Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
Neurochem Int. 2018 Jan;112:288-296. doi: 10.1016/j.neuint.2017.08.011. Epub 2017 Aug 16.
Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic neurons in the substantia nigra. Oxidative stress has been reported to be closely related to the pathogenesis and worsening of symptoms of PD. One therapeutic strategy is to alleviate neuronal injuries caused by oxidative stress. In this study, we investigated protective effects of royal jelly (RJ) fatty acids and their derivatives on oxidative stress-induced cell death using human neuroblastoma SH-SY5Y cells. 4-Hydroperoxy-2-decenoic acid ethyl ester (HPO-DAEE), a synthesized RJ fatty acid derivative, markedly induced antioxidant enzymes such as heme oxygenase-1 (HO-1). Pretreatment with HPO-DAEE protected against 6-hydroxydopamine (6-OHDA)-induced cell death. NF-E2-related factor 2 (Nrf2), a master regulator of antioxidative responses, plays a key role in the acquisition of resistance to oxidative stress. HPO-DAEE elicited nuclear accumulation of Nrf2 and activated antioxidant response element (ARE), a cis-activating regulatory element, indicating that HPO-DAEE induced expression of antioxidant genes through Nrf2-ARE signaling. Recently, the activating transcription factor-4 (ATF4) has been shown to cooperate with Nrf2 and modulate antioxidant gene expression. We also found that HPO-DAEE promoted phosphorylation of eukaryotic initiation factor 2α (eIF2α), which is an upstream effector of ATF4, and subsequent nuclear accumulation of ATF4. The eIF2α phosphatase inhibitor, salubrinal, augmented HPO-DAEE-induced HO-1 expression and protection against 6-OHDA-induced cell death. These results indicate that HPO-DAEE activates both the Nrf2-ARE and eIF2α-ATF4 pathways. Moreover, ROS generation occurred upon treatment of SH-SY5Y cells with HPO-DAEE, and the antioxidants N-acetylcysteine and glutathione suppressed HPO-DAEE-induced activation of the Nrf2-ARE and eIF2α-ATF4 pathways. Therefore, sublethal oxidative stress caused by HPO-DAEE is likely to activate both these pathways. Taken together, we conclude that HPO-DAEE elicits adaptive responses to oxidative stress through cooperative activation of the Nrf2-ARE and eIF2α-ATF4 pathways.
帕金森病（PD）是一种神经退行性疾病，其特征是黑质中多巴胺能神经元进行性退化。氧化应激已被报道与 PD 的发病机制和症状恶化密切相关。一种治疗策略是减轻氧化应激引起的神经元损伤。在这项研究中，我们使用人神经母细胞瘤 SH-SY5Y 细胞研究了蜂王浆（RJ）脂肪酸及其衍生物对氧化应激诱导的细胞死亡的保护作用。4-羟基-2-癸烯酸乙酯（HPO-DAEE），一种合成的 RJ 脂肪酸衍生物，显著诱导血红素加氧酶-1（HO-1）等抗氧化酶。HPO-DAEE 预处理可防止 6-羟多巴胺（6-OHDA）诱导的细胞死亡。核因子 E2 相关因子 2（Nrf2）是抗氧化反应的主要调节剂，在获得对氧化应激的抗性中起关键作用。HPO-DAEE 引起 Nrf2 的核积累并激活抗氧化反应元件（ARE），一种顺式激活调节元件，表明 HPO-DAEE 通过 Nrf2-ARE 信号诱导抗氧化基因的表达。最近，激活转录因子-4（ATF4）已被证明与 Nrf2 合作并调节抗氧化基因表达。我们还发现，HPO-DAEE 促进真核起始因子 2α（eIF2α）的磷酸化，这是 ATF4 的上游效应物，随后 ATF4 核积累。eIF2α 磷酸酶抑制剂 salubrinal 增强了 HPO-DAEE 诱导的 HO-1 表达和对 6-OHDA 诱导的细胞死亡的保护作用。这些结果表明 HPO-DAEE 激活了 Nrf2-ARE 和 eIF2α-ATF4 途径。此外，用 HPO-DAEE 处理 SH-SY5Y 细胞会导致 ROS 的产生，抗氧化剂 N-乙酰半胱氨酸和谷胱甘肽抑制 HPO-DAEE 诱导的 Nrf2-ARE 和 eIF2α-ATF4 途径的激活。因此，HPO-DAEE 引起的亚致死氧化应激可能会通过协同激活 Nrf2-ARE 和 eIF2α-ATF4 途径来激活这两条途径。综上所述，我们得出结论，HPO-DAEE 通过协同激活 Nrf2-ARE 和 eIF2α-ATF4 途径来引发对氧化应激的适应性反应。
