目的:探讨人类免疫缺陷病毒1型(human immunodeficiency virus type 1,HIV-1)gp120 V3环致CHME-5小胶质细胞炎症反应与铁死亡的关系,并观察p53和铁死亡对该炎症反应的影响及可能机制.方法:体外培养人源CHME-5小胶质细胞,设立空白组、随机肽段组、HIV-1 gp120 V3环组、HIV-1 gp120 V3环+ferrostatin-1(Fer-1;铁死亡抑制剂)组和HIV-1 gp120 V3环+pifithrin-α(p53抑制剂)组.分别采用HIV-1 gp120 V3环(终浓度2 mg/L)和随机肽段(终浓度2 mg/L)处理CHME-5细胞24 h;Fer-1(终浓度20 μmol/L)和pifithrin-α(终浓度10 μmol/L)预处理CHME-5细胞2 h,HIV-1 gp120 V3环(终浓度2 mg/L)再处理24 h.ELISA法检测各组细胞上清液中炎症因子水平;Western blot法检测铁死亡相关蛋白[转铁蛋白受体1(transferrin receptor-1,TFR-1)、溶质载体家族7成员11(solute carrier family 7 member 11,SLC7A11)和谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)]及p53的蛋白表达;酶标仪法检测细胞内亚铁离子(Fe2+)和谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活性.结果:(1)ELISA结果显示,与对照组相比,gp120 V3环组炎症因子白细胞介素1β(interleukin-1β,IL-1β)、IL-6和肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)水平显著升高(P＜0.01);与gp120 V3环组相比,gp120 V3环+Fer-1组和gp120 V3环+pifithrin-α组炎症因子IL-1β、IL-6和TNF-α水平显著下降(P＜0.01);(2)Western blot结果显示,与对照组相比,gp120 V3环组蛋白p53显著上调(P＜0.01),铁死亡相关蛋白TFR-1显著上调(P＜0.01),SLC7A11和GPX4显著下调(P＜0.01);与gp120 V3环组相比,gp120 V3环+pifithrin-α组铁死亡相关蛋白TFR-1显著下降(P＜0.05),SLC7A11和GPX4蛋白显著升高(P＜0.05);(3)与对照组相比,gp120 V3环组Fe2+含量显著增加(P＜0.01),GSH-Px活性显著降低(P＜0.01);与gp120 V3环组相比,gp120 V3环+Fer-1组和gp120 V3环+pifithrin-α组Fe2+含量显著下降(P＜0.05),GSH-Px活性显著升高(P＜0.01).结论:HIV-1 gp120 V3环致CHME-5小胶质细胞炎症中存在铁死亡,且抑制铁死亡能减轻炎症.HIV-1 gp120 V3环致CHME-5小胶质细胞炎症与p53蛋白调控铁死亡有关,抑制p53可减轻铁死亡和炎症反应.

目的:探讨自噬关键蛋白p62在HIV-1 gp120 V3环所致小鼠神经炎症中的作用及相关信号分子机制.方法:野生型C57BL6小鼠随机分成4组:空白组、假手术组(人工脑脊液组)、模型组(gp120 V3环组)及gp120 V3环+NF-κB活化阻滞剂BAY 11-7082组,每组12只.用Morris水迷宫检测小鼠学习记忆能力;免疫荧光染色检测海马和皮层Iba-1表达水平;ELISA法检测海马和皮层炎症因子的表达水平;Western blot检测海马和皮层相关蛋白表达水平.结果:(1)Morris水迷宫结果显示,与空白组相比,模型组小鼠逃避潜伏期显著延长(P<0.01),平台区域停留时间及穿越平台次数显著减少(P<0.05);与模型组相比,gp120 V3环+BAY 11-7082组小鼠逃避潜伏期显著缩短(P<0.01),平台区域停留时间及穿越平台次数显著增加(P<0.05).(2)免疫荧光染色结果显示,与空白组相比,模型组海马和皮层Iba-1荧光强度显著增强(P<0.05);与模型组相比,gp120 V3环+BAY 11-7082组海马和皮层Iba-1荧光强度显著降低(P<0.05).(3)ELISA结果显示,与空白组相比,模型组IL-1β、TNF-α和IL-6水平均显著上调(P<0.05);与模型组相比,gp120 V3环+BAY 11-7082组IL-1β、TNF-α和IL-6水平显著下调(P<0.05).(4)Western blot结果显示,与空白组相比,模型组p62蛋白表达水平显著上调(P<0.01),p-p65/p65及p-IκB/IκB比值均显著升高(P<0.01);与模型组相比,gp120 V3环+BAY 11-7082组p62蛋白显著下调(P<0.05),p-p65/p65及p-IκB/IκB比值均显著下降(分别P<0.01和P<0.05).结论:HIV-1 gp120 V3环所致小鼠学习记忆功能障碍的机制可能与通过激活p62/NF-κB信号通路引起神经炎症有关,p62-NF-κB正反馈环的抑制可能会减轻神经炎症.

HIV-associated neurocognitive disorders (HAND) are a collective name for neurological disorders associated with HIV-1 infection. The incidence and severity of HAND are increased by concomitant opioid use disorder, such as heroin and morphine abuse. Our previous study showed that the HIV-1 envelope protein gp120 and morphine synergistically induce apoptosis in rat hippocampal neurons. However, the underlying mechanism remains unclear. We hypothesized that morphine and gp120 activated the neuronal apoptosis signaling pathway via their typical membrane receptors. If they shared key signaling molecules, their induction of neuronal apoptosis could be inhibited by blocking these targets. We found that morphine and gp120V3 loop synergistically induced hippocampal neuron apoptosis, mediated by activating the extracellular signal-regulated kinase (ERK) pathway, increasing the intracellular Ca2 + concentration and expression of caspase-, and reducing the mitochondrial membrane potential. The ERK inhibitor PD98509 and the phosphatidylinositol 3-kinase activator IGF-1 blocked this effect. These results indicate that ERK plays a crucial role in the apoptosis of hippocampal neurons in HAND.

Combined antiretroviral therapy (cART) has significantly increased the life expectancy of AIDS patients; however, the prevalence of the neurocognitive impairment associated with HIV-1 continues to rise. HIV-1 gp120, an important subunit of the envelope spikes that decorate the surface of virions, is found to activate microglia in central nervous system (CNS) which leads to the cognitive and behavioral dysfunction known as HIV-1 associated neurocognitive disorder(HAND), and the V3 loop is the most important toxic domain of gp120. A study has shown that autophagy plays key role in the activation of microglia, p62 is an important autophagy substrate protein that is elevated in neuroinflammation. In this study, we sought to explore the role of p62 in gp120 V3 loop-mediated microglial activation. Our results demonstrated that exposure of CHME-5 cells to the gp120 V3 loop resulted in elevated inflammatory cytokines, accompanied by autophagy dysfunction and p62 upregulation. Subsequently, we found that the p62-dependent Nrf2 noncanonical signaling pathway was activated and that HO-1, the target protein of Nrf2, was also upregulated. Interestingly, the elevation of inflammatory factors caused by the gp120 V3 loop was significantly alleviated after knocking down p62, Nrf2 and HO-1. Further investigation revealed that in the microglial inflammation induced by the gp120 V3 loop, up-regulated HO-1 promoted the expression of iNOS by interacting with iNOS, while enhanced autophagy by RAPA promoted the degradation of iNOS and alleviated inflammation. These findings provide a new perspective on the relationship between noncanonical Nrf2 activation and autophagy in microglial inflammation and an experimental basis for HAND prevention and treatment.

Autophagy is a lysosome-mediated cell content- dependent degradation pathway that leads to enhanced inflammation in an uncontrolled state. This study examined the role of autophagy in lipopolysaccharide (LPS)-induced brain inflammation and the effects of the traditional Chinese medicine ligustrazine on LPS-induced neurocognitive impairment in rats. Furthermore, the molecular mechanisms by which ligustrazine influences neurocognitive impairments were explored. The production of the inflammatory mediators interleukin (IL)-1β and tumor necrosis factor (TNF)-α was analyzed using ELISAs, and the expression levels of the autophagy marker microtubule-associated protein light chain 3 (LC3) II/I were analyzed using western blotting. LPS exposure upregulated the expression of IL-1β and TNF-α and downregulated the expression of LC3 II/I. Ligustrazine activated autophagy by preventing the expression of phosphoinositide 3-kinase (PI3K), phosphorylated protein kinase B (p-AKT), and phosphorylated mammalian target of rapamycin (p-mTOR). The present results suggest that ligustrazine improved LPS-induced neurocognitive impairments by activating autophagy and ameliorated neuronal injury by regulating the PI3K/AKT/mTOR signaling pathway. These findings provide an important reference for the prevention and treatment of neuroinflammation.

目的:探讨中药单体川芎嗪对脂多糖(lipopolysaccharide,LPS)诱导的神经认知障碍的影响及其功能影像学机制.方法:将36只SD大鼠随机分成空白对照组、假手术组、模型组(LPS组)、低剂量川芎嗪组、中剂量川芎嗪组和高剂量川芎嗪组,每组6只.模型组及低剂量、中剂量和高剂量川芎嗪组均行侧脑室注射LPS,每只150μg;假手术组侧脑室注射等量的脑脊液;空白对照组不做处理;低、中和高剂量川芎嗪组分别腹腔注射50 mg/kg、100 mg/kg和200 mg/kg的盐酸川芎嗪注射液.用Morris水迷宫实验观察LPS对神经认知障碍的影响;酶联免疫吸附测定(ELISA)法检测脑组织匀浆中白细胞介素1β(IL-1β)和肿瘤坏死因子 α(TNF-α)的含量;同时用影像学扫描IVIM D和IVIM D*功能序列,测定LPS致神经认知障碍的影像学纯水分子的扩散运动成分和血流灌注相关的扩散运动.结果:Morris水迷宫大鼠空间学习和记忆结果显示:与对照组比,模型组的逃避潜伏期延长,平台周边穿梭次数减少,目标象限停留时间缩短(P<0.05);与模型组相比,低剂量川芎嗪组逃避潜伏期缩短,平台周边穿梭次数增加,目标象限停留时间延长(P<0.05),中、高剂量川芎嗪组无显著差异.ELISA结果显示:与对照组比,模型组皮层和海马区的IL-1β和TNF-α均增加(P<0.05);与模型组比,低剂量组皮层和海马区IL-1β和TNF-α均降低(P<0.05),中、高剂量组无显著差异.影像结果显示:与对照组比,模型组皮层和海马的IVIM D、IVIM D*和f值均降低(P<0.05);与模型组比,低剂量组皮层和海马的IVIM D、IVIM D*和f值均升高(P<0.05),中、高剂量组IVIM D、IVIM D*和f值无显著差异.结论:川芎嗪具有减轻LPS所致大鼠神经认知障碍的作用,其机制可能与川芎嗪通过促进脑中水分子扩散运动和脑血流灌注而抑制炎症反应有关.

Neuroinflammation is a predisposing factor for several neurodegenerative diseases. The purpose of this study was to evaluate the protective effect of madecassoside (MA) in lipopolysaccharide (LPS)-induced cognitive impairment and neuroinflammation in rats. MA has many protective effects such as antioxidant and anti-inflammatory properties. We investigated whether MA could improve neurocognitive dysfunction caused by intracerebroventricular injection of LPS. We examined the effects and mechanisms of action of MA on LPS-induced neuroinflammation in the cortex and hippocampus. Our study revealed that MA (120 mg/kg, i.g) treatment for 14 days reduced LPS-induced neurotoxicity by reducing cognitive impairments and suppressing the production of inflammatory cytokines such as interleukin 1 beta (IL-1 beta), tumor necrosis factor alpha(TNF-alpha), and interleukin 6(IL-6) via activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. Furthermore, MA treatment enhanced protein levels of heme oxygenase (HO)-1 by upregulating Nrf2 in LPS-stimulated neurotoxicity. Collectively, these results suggest that MA is effective in preventing neurodegenerative diseases by improving memory functions due to its anti-inflammatory activities and activation of Keapl-Nrf2/HO-1 signaling. As such, MA may be a potential therapy for addressing memory impairment caused by neuroinflammation.