Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China,; College of Life Sciences, Anhui Medical University, Anhui 230032, PR China.
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China,; Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou 215009, PR China.
Cell Signal. 2022 Jun;94:110330. doi: 10.1016/j.cellsig.2022.110330. Epub 2022 Apr 4.
Oxidative stress is closely related to the pathogenesis of Parkinson's disease (PD), a typical neurodegenerative disease. NADPH oxidase 2 (NOX2) is involved in hydrogen peroxide (HO) generation. Recently, we have reported that treatment with HO and PD toxins, including 6-hydroxydopamine (6-OHDA), 1-Methyl-4-phenylpyridin-1-ium (MPP) and rotenone, induces neuronal apoptosis by inhibiting the mTOR pathway. Here, we show that treatment with 6-OHDA, MPP or rotenone induced HO generation by upregulating the levels of NOX2 and its regulatory proteins (p22, p40, p47, p67, and Rac1), leading to apoptotic cell death in PC12 cells and primary neurons. Inhibition of NOX2 with apocynin or diphenyleneiodonium, or knockdown of NOX2 powerfully attenuated PD toxins-evoked NOX2 and HO, thereby hindering activation of AMPK, inhibition of Akt/mTOR, and induction of apoptosis in neuronal cells. Pretreatment with catalase, a HO-scavenging enzyme, blocked the effects of PD toxins on NOX2-dependent HO production, AMPK/Akt/mTOR signaling and apoptosis in the cells. Similar effects were also seen in the cells pretreated with Mito-TEMPO, a mitochondria-selective superoxide scavenger, implying a mitochondrial HO-dependent mechanism involved. Further research revealed that ectopic expression of constitutively active Akt or dominant negative AMPKα, or inhibition of AMPK with compound C suppressed PD toxins-induced expression of NOX2 and its regulatory proteins, as well as consequential HO production and apoptosis in the cells. Taken together, these results indicate that certain PD toxins can impede the AMPK/Akt-mTOR signaling pathway leading to neuronal apoptosis by eliciting NOX2-derived HO production. Our findings suggest that neuronal loss in PD may be prevented by regulating the NOX2, AMPK/Akt-mTOR signaling and/or applying antioxidants to ameliorate oxidative stress.
氧化应激与帕金森病 (PD) 的发病机制密切相关，PD 是一种典型的神经退行性疾病。NADPH 氧化酶 2 (NOX2) 参与过氧化氢 (HO) 的生成。最近，我们报道了 HO 和 PD 毒素（包括 6-羟多巴胺 (6-OHDA)、1-甲基-4-苯基吡啶-1- 离子 (MPP) 和鱼藤酮）的处理通过抑制 mTOR 通路诱导神经元凋亡。在这里，我们表明，用 6-OHDA、MPP 或鱼藤酮处理会通过上调 NOX2 及其调节蛋白（p22、p40、p47、p67 和 Rac1）的水平诱导 HO 的产生，导致 PC12 细胞和原代神经元的凋亡细胞死亡。用 apocynin 或二苯并碘化物抑制 NOX2，或敲低 NOX2，可强力减弱 PD 毒素诱导的 NOX2 和 HO，从而抑制 AMPK 的激活、Akt/mTOR 的抑制以及神经元细胞的凋亡诱导。过氧化氢清除酶 catalase 的预处理阻断了 PD 毒素对 NOX2 依赖性 HO 产生、AMPK/Akt/mTOR 信号和细胞凋亡的影响。在用线粒体选择性超氧化物清除剂 Mito-TEMPO 预处理的细胞中也观察到类似的效果，表明涉及线粒体 HO 依赖性机制。进一步的研究表明，组成型激活的 Akt 或显性负性 AMPKα 的异位表达，或用化合物 C 抑制 AMPK 可抑制 PD 毒素诱导的 NOX2 及其调节蛋白的表达，以及随后在细胞中产生 HO 和凋亡。总之，这些结果表明，某些 PD 毒素通过引发 NOX2 衍生的 HO 产生来抑制 AMPK/Akt-mTOR 信号通路，从而导致神经元凋亡。我们的研究结果表明，通过调节 NOX2、AMPK/Akt-mTOR 信号和/或应用抗氧化剂来改善氧化应激，可能可以防止 PD 中的神经元丢失。
