Keap1-Nrf2-ARE信号通路及其激活剂的研究进展

Keap1-Nrf2-ARE信号通路是细胞防御氧化应激损伤的最重要机制之一。许多具有解毒、抗氧化防御功能的蛋白质,其转录调控都依赖于Nrf2信号通路的激活。研究表明,Nrf2信号通路已成为氧化应激相关疾病(神经退行性疾病、癌症、心血管系统疾病、代谢和炎症等疾病)预防和治疗的靶点。因此,Nrf2信号通路的激活剂在多种氧化应激诱发的疾病方面都表现出良好的预防及治疗作用,发现及研究Nrf2信号通路的激活剂已越来越受到研究者们的重视。该文概述了Keap1-Nrf2-ARE通路的作用机制,并阐述了Keap1-Nrf2-ARE信号通路小分子激活剂的研究进展。     

亚硒酸钠通过Keap1/Nrf2/ARE信号通路诱导人肺腺癌A549细胞凋亡

目的探究亚硒酸钠诱导人肺腺癌A549细胞凋亡的作用及可能的分子机制。方法 MTT法检测不同浓度亚硒酸钠对人肺腺癌A549细胞的抑制增殖率;倒置荧光显微镜观察细胞经亚硒酸钠处理后的形态学改变;流式细胞术检测细胞凋亡率;激光共聚焦观察活性氧荧光强度;多功能酶标仪测定氧化应激参数含量;Western blot检测Keap1/Nrf2/ARE信号通路蛋白的表达,以及Nrf2在细胞质和细胞核中的蛋白表达情况。结果亚硒酸钠剂量依赖性地抑制人肺腺癌A549细胞增殖,亚硒酸钠作用于人肺腺癌A549细胞24 h后,通过Hoechst 33342固定和流式细胞术分析,细胞凋亡率明显增加;亚硒酸钠可使活性氧和丙二醛水平明显升高,还原型谷胱甘肽和超氧化物歧化酶含量明显下降;同时亚硒酸钠能够下调Keap1、Nrf2和HO-1蛋白的表达,并且抑制Nrf2发生核位移。结论亚硒酸钠通过抑制人肺腺癌A549细胞增殖,诱导细胞凋亡,调节细胞内的氧化应激反应,调控Keap1/Nrf2/ARE抗氧化信号通路,从而促进肿瘤细胞凋亡。     

Nrf2/ARE信号通路及其相关药物研究进展

Nrf2/ARE信号通路是细胞氧化应激反应中的关键通路,其调控的下游抗氧化蛋白和Ⅱ相解毒酶在细胞防御保护中发挥重要作用。现有研究显示Nrf2/ARE通路在抗炎、抗肿瘤、神经保护、抗凋亡等多方面具有重要作用,以Nrf2为靶点的药物有望用于多发性硬化、糖尿病、神经退行性疾病、肿瘤等多种疾病的治疗,其中已有富马酸二甲酯、巴多克沙龙等多个新药进入临床研究阶段。就Nrf2/ARE通路与疾病的关系及以其为靶点的新药研发进展做一综述。     

Nrf2-ARE信号通路参与肝脏疾病病理机制研究进展

核因子NF-E2相关因子2(Nrf2)是细胞抵御氧化应激的一个重要转录因子,它能够在活性氧或亲电试剂的刺激下,转位进入细胞核,并与抗氧化反应元件(ARE)相互作用,从而诱导下游保护性Ⅱ相解毒酶和抗氧化酶的表达,达到细胞保护的作用。氧化应激是诸多肝脏疾病共同的发病机制,而Nrf2-ARE是体内一条极为重要的抗氧化应激信号通路,该通路在肝脏疾病的发生、发展及预防过程中起着非常重要的作用,Nrf2或将成为肝脏疾病治疗的新靶点。该文综述了Nrf2-ARE信号通路参与肝脏疾病病理机制的最新研究进展,以期为日后相关研究提供参考。     

茯苓酸调节Nrf2/Keap1/ARE信号通路改善脂多糖诱导肺泡上皮细胞氧化应激损伤研究

摘要：目的:研究茯苓酸（PA）对脂多糖（LPS）诱导的人肺泡上皮细胞氧化应激损伤的影响,以及核因子红细胞2相关因子2/Kelch样ECH关联蛋白1/抗氧化反应元件（Nrf2/Keap1/ARE）信号通路在此过程中的作用。方法:培养人肺泡上皮细胞HPAEpiC,使用CCK-8法筛选适合的PA处理浓度。将HPAEpiC细胞分为Control组、LPS组、LPS+PA组、LPS+PA+sh-NC组和LPS+PA+sh-Nrf2组。TUNEL染色法检测各组HPAEpiC细胞凋亡情况;检测各组HPAEpiC细胞中活性氧（ROS）的产生、丙二醛（MDA）水平以及总超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）活性;Western blot检测各组HPAEpiC细胞中p53、B淋巴细胞瘤-2基因相关X蛋白（Bax）、Nrf2、Keap1和血红素氧化酶1（HO-1）蛋白表达情况。结果:根据CCK-8结果选用4μmol·L-1的PA用于后续研究。LPS诱导后HPAEpiC细胞中TUNEL阳性细胞率与p53和Bax蛋白水平均升高;ROS的产生、MDA水平均增高,SOD和GSH-Px活性降低;Nrf2、HO-1蛋白质水平减少,Keap1蛋白质水平增加（P＜0.05）。使用PA处理可以减轻LPS诱导对以上指标的影响（P＜0.05）。敲低Nrf2可部分逆转PA处理对LPS诱导的HPAEpiC细胞的影响（P＜0.05）。结论:PA可抑制LPS诱导的肺泡上皮细胞氧化应激损伤和凋亡反应,其机制可能与激活Nrf2/Keap1/ARE信号通路有关。     

Nrf2在神经退行性疾病中的作用及激活剂的研究进展

氧化应激被认为是多种神经退行性疾病的发病机制之一,在疾病的发生发展过程中起重要作用。核转录因子E2相关因子2(nuclear factor erythroid 2 related factor 2,Nrf2)是内源性抗氧化防御系统的关键调节蛋白,在氧化应激条件下核转录因子Nrf2发生核转位,与抗氧反应元件(antioxidant response element,ARE)结合,启动下游大量的抗氧化酶基因的转录,发挥抗氧化的保护作用。Nrf2诱导剂在多种神经退行性疾病模型中能减缓氧化应激,表现出良好的神经保护作用。如何有效地激活Nrf2-ARE通路已经越来越受到研究者的重视。本文概述了Nrf2-ARE通路的作用机制并具体阐述了激活Nrf2在不同的神经退行性疾病中所发挥的保护作用,同时统计了目前研究中的Nrf2激活剂。     

番茄红素调节Keap1/Nrf2/ARE信号通路对精神分裂大鼠认知障碍和氧化应激反应的影响

目的 探究番茄红素调控Kelch样环氧氯丙烷相关蛋白1（Keap1）/核因子E2相关因子2（Nrf2）/抗氧化反应元件（ARE）通路,影响精神分裂症大鼠的氧化应激反应和认知功能。方法 构建精神分裂症大鼠模型,将大鼠随机分为对照组、氯丙嗪组、模型组以及番茄红素高、低剂量组和番茄红素+Nrf2抑制剂组,每组各10例。Morris水迷宫实验检测各组大鼠认知功能;Tunel染色观察并计算各组大鼠海马组织中神经元凋亡率;酶联免疫吸附测定法（ELISA）检测大鼠血清中过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）水平;Western blotting法检测各组大鼠海马组织中Keap1、Nrf2和ARE下游抗氧化蛋白HO-1的表达水平。结果 与模型组相比,番茄红素组大鼠水迷宫实验中逃避潜伏期明显缩短（2～5d）,海马组织细胞凋亡率显著降低,血清CAT、GSH-Px、SOD水平和海马组织Keap1、Nrf2、HO-1蛋白表达量显著升高（P<0.05）;与番茄红素高剂量组相比,番茄红素低剂量组、番茄红素+Nrf2抑制剂组大鼠水迷宫实验中逃避潜伏期明显延长（2～5d）,海马组织细胞凋亡率显著升高,血清CAT、GSH-Px、SOD水平和海马组织Keap1、Nrf2、HO-1蛋白表达量显著降低（P<0.05）。结论 番茄红素可通过调控Keap1/Nrf2/ARE通路,促进Keap1、Nrf2、HO-1的表达,缓解氧化应激,改善认知功能,从而缓解精神分裂,改善病情。     

表没食子儿茶素没食子酸酯作为Nrf2/ARE信号通路激活剂的研究进展

表没食子儿茶素没食子酸酯(EGCG)是绿茶含量最多、活性最强的有效成分,是绿茶生物学功效的主要研究对象。大量研究表明,EGCG具有抗氧化、清除自由基、抗癌等生物学活性,并参与多条信号通路的调控。核转录因子红细胞系-2p45相关因子2/抗氧化反应元件(Nrf2/ARE)信号通路调节Ⅱ相解毒酶、抗氧化酶和抗炎蛋白等物质转录,直接影响细胞氧化应激水平,是调控氧化还原水平的核心通路。研究表明,EGCG对Nrf2/ARE信号通路具有激活作用,在泌尿、呼吸、心脑血管和消化等众多系统中发挥作用。本文总结了EGCG作为Nrf2/ARE信号通路激活剂的研究进展,为EGCG开发利用提供参考。     

Nrf2/ARE信号通路与肝脏疾病的研究进展

对近几年关于Nrf2在各种肝脏疾病中作用的文献进行分析、归纳、总结,发现Nrf2/ARE信号通路的激活在防治病毒性肝炎、酒精性和非酒精性肝炎、胆汁淤积型肝损伤、肝纤维化、肝癌等肝脏疾病中起着重要作用。Nrf2/ARE通路在肝脏病理生理学过程中发挥重要作用,可能为防治肝脏疾病提供新的治疗靶点。     

Nrf2与p53/p21信号通路在肿瘤中作用的研究进展

氧化应激普遍存在于肿瘤发生和发展的病理过程中。转录因子红细胞系-2p45相关因子-2(NF-E2 p45-related factor 2,Nrf2)信号通路是人体内重要的抗氧化机制,其产物保护机体的细胞免受毒性和氧化性损伤,对癌症的治疗具有重要的价值。肿瘤抑制基因p53能显著促进细胞周期调控因子p21转录活性,p53/p21信号通路是控制细胞周期进程以及调节肿瘤细胞凋亡的核心调控途径。然而,目前有关Nrf2和p53/p21信号通路在肿瘤中的相互调控机制尚未完全阐明。本文将从Nrf2信号通路的组成,p53/p21信号通路的结构与功能,Nrf2信号通路与p53/p21信号通路相互调控对肿瘤的作用关系以及相关抗肿瘤药物的研究进展等方面进行阐述。     

Cerebral metabolism of [3H]-p-chloroamphetamine

The time-dependent metabolism of intraventricularly administered $\text{[}{}^3\text{H}\text{]-p-}\text{chloroamphetamine}$ was followed. The parent compound and its metabolites were recovered by high pressure liquid chromatography and characterized by high pressure liquid chromatography, thin-layer chromatography, and gas chromatography-mass spectrometry. By 4 hr after injection, two major toluene-soluble metabolites were present in brain. Their biological half-lives were different from the parent compound. On the basis of their analyses, one of the metabolites is p-chloronorephedrine, the other (P₃) is as yet unidentified. Pretreatment with Lilly 110140 prevented or markedly reduced the synthesis of both p-chloronorephedrine and P₃. Iprindole prevented the synthesis of p-chloronorephedrine. The P₃ appeared first in the brain then in the liver, suggesting that both of these organs can metabolize p-chloroamphetamine to this compound. The metabolites were recovered primarily from the nuclear and microsomal fractions following subcellular fractionation of the brain, with small quantities present in the synaptosomal fraction. The level of metabolites was higher in the brainstem than in the neocortex. Glutathione, administered simultaneously with p-chloroamphetamine either intraventricularly or intraperitoneally failed to alter the toxicity of p-chloroamphetamine.     

Clevudine University of Georgia/Abbott/Bukwang/Triangle/Yale University

The pyrimidine analog, clevudine (L-FMAU: 2'-fluoro-5-methyl-beta-L-arabinofuranosyluridine) is a potent antihepatitis B virus (HBV) and anti-Epstein-Barr virus (EBV) agent, discovered by researchers at the University of Georgia, in collaboration with Yale University and Bukwang. Bukwang transferred its technology to Triangle Pharmaceuticals in 1998 together with a license to develop clevudine worldwide except Korea [279649], [281942]. In June 1999, Triangle and Abbott Laboratories entered into a strategic alliance to copromote antiviral products including L-FMAU [326798]. In September 2000, Triangle Pharmaceuticals Inc initiated a 30-day phase I/II evaluation of clevudine in HBV-infected patients [381755]. Clevudine is a much less toxic derivative of the toxic agent P-D-FMAU. The mechanism of action of clevudine is not yet clear, but the agent induces a rapid decrease in HBV nucleic acid as doses increase from 0.3 to 10 mg/kg [319145]. It is believed that the target for clevudine lies in the viral replication mechanism. Clevudine is phosphorylated to the triphosphate form intracellularly. This is removed slowly from the cells, thus exerting a sustained inhibitory antiviral activity [178173], [320720], [320721].     

Spotlight from the American Society for Preventive Cardiology on Key Features of the 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guidelines on the Management of Blood Cholesterol

The 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol retains focus on recommendations for statin treatment in the original four statin-eligible groups [those with atherosclerotic cardiovascular disease (ASCVD), diabetes, low-density lipoprotein cholesterol (LDL-C) ≥ 190 mg/dL, and higher risk primary prevention] without the use of treatment initiation or target LDL-C levels from the earlier 2013 American College of Cardiology/American Heart Association (ACC/AHA) guideline, but has several new features. First, patients with primary prevention are divided into those who are at low (< 5%), borderline (5% to < 7.5%), intermediate (7.5% to < 20%), and high (≥ 20%) risk based on the ASCVD risk estimator. Moreover, the new guideline goes further to consider a wider range of factors [now called “risk enhancers”—premature family history of ASCVD, persistently high LDL-C, chronic kidney disease (CKD), metabolic syndrome, conditions specific to women, inflammatory diseases, and high-risk ethnicities] that can be used to better inform the treatment decision. Moreover, more detailed recommendations on how the results of coronary calcium scanning can be used to inform the treatment decision are provided, including how it may be used to “de-risk” certain patients for delaying or avoiding the use of statin therapy. There are also specific sections for cholesterol management in other patient subgroups including women, children, certain ethnic groups, those with CKD, chronic inflammatory disorders and HIV, as well as discussion on the management of hypertriglyceridemia. Importantly, for persons with known ASCVD, a distinction is made for those who are at “very high risk” based on having had two major ASCVD events or one major event and two or more other high risk conditions, such as diabetes or other major risk factors, or bypass surgery or percutaneous intervention. Finally, the concept of a threshold LDL-C for initiating a non-statin therapy (after considering highest tolerated statin dosage) is provided, with ezetimibe recommended as the key non-statin to be added if the LDL-C still remains ≥ 70 mg/dL for all ASCVD patients, and in those who are at “very high risk”, further consideration for using a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor. While the new guideline does have greater detail (and arguably, complexity), the refinements provide a strategy for guiding the clinician to target both statin and non-statin therapy to those most likely to derive benefit.     

Pitavastatin Nissan/Kowa Yakuhin/Novartis/Sankyo

Pitavastatin (nisvastatin) is an HMG CoA reductase inhibitor being developed jointly by Nissan, Kowa Kogyo, Novartis and Sankyo for the potential treatment of atherosclerosis and hyperlipidemia.     

Amlodipine/Valsartan/Hydrochlorothiazide

Amlodipine/valsartan/hydrochlorothiazide (HCTZ) is a fixed-dose combination of the well established antihypertensive agents amlodipine (a calcium channel antagonist), valsartan (an angiotensin II receptor antagonist), and HCTZ (a thiazide diuretic). In patients with moderate or severe hypertension, triple combination therapy with amlodipine + valsartan + HCTZ produced significantly greater reductions from baseline in mean sitting systolic and diastolic BP (msSBP and msDBP) than either valsartan + HCTZ, amlodipine + HCTZ, or amlodipine + valsartan in a large, 8-week, randomized, double-blind, multinational, phase III trial. Furthermore, the proportion of patients achieving overall BP control at endpoint was significantly greater with the triple combination regimen than with any of the dual regimens, with significantly more triple combination recipients achieving msSBP and msDBP control at each assessment throughout the trial. Subgroup analyses of this study suggested that amlodipine + valsartan + HCTZ was generally more effective in reducing BP and providing overall BP control than the dual combination therapies, irrespective of age, race, gender, ethnicity, or hypertension severity. Several smaller studies provide data that support the efficacy of amlodipine + valsartan + HCTZ in patients whose BP is inadequately controlled with amlodipine + valsartan, amlodipine + HCTZ, or valsartan + HCTZ dual combination therapy. Treatment with amlodipine + valsartan + HCTZ for up to 8 weeks was generally well tolerated in the large, phase III trial, with most adverse events being transient and of mild to moderate severity.     

N-Nitroso-N-Methyldodecylamine and N-Nitroso-N-Methyltetradecylamine in household dishwashing liquids

Eleven household dishwashing liquids and four household surface cleaners were analysed for N-nitroso-N-methyldodecylamine and N-nitroso-N-methyltetradecylamine by gas chromatography with detection using a Thermal Energy Analyzer. Both nitrosamines were found in three of the dishwashing detergents and one of the surface cleaners. [1-¹⁴C]-N-Nitroso-N-methyldodecylamine was used to determine recoveries, which were between 65 and 88%. Levels of N-nitroso-N-methyldodecylamine ranged from 112 to 661 ppb and those of N-nitroso-N-methyltetradecylamine from 46 to 151 ppb. A simple method was developed to screen the products for N,N-dimethyldodecylamine-N-oxide, a surfactant ingredient suspected of being the source of these nitrosamines. By application of this method it was established that all of the products formulated with this amine oxide contained these two nitrosamines, whereas in products that did not contain this ingredient, these nitrosamines were not detected.     

PROTON AND POTASSIUM TRANSPORT BY H+/K+-ATPases

1. H⁺/K⁺-ATPases are members of the P-type ATPase multigene family. The prototypical H⁺/K⁺-ATPase is the protein that acidifies gastric luminal contents. The physiological and pharmacological significance of this pump has led to a detailed investigation of its biochemistry and molecular and cell biology. 2. Recently, a number of closely related H⁺/K⁺-ATPase isoforms have been discovered. These isoforms are present in organs other than the stomach, including the colon and kidney, where they contribute to acid—base and potassium homeostasis. The structure, expression and physiological roles of the gastric H⁺/K⁺-ATPase and other isoforms are reviewed.     

INTERACTIONS OF Na+, H2O2 AND THE Na+-Ca2+ EXCHANGER STIMULATE Ca2+ RELEASE IN CK1.4 CELLS

1. The present study aimed to demonstrate that interactions of cations, hydrogen peroxide (H₂O₂) and the Na⁺-Ca²⁺exchanger stimulate Ca²⁺ release and oscillations of cytosolic Ca²⁺ [Ca²⁺]i in non-transfected Chinese Hamster Ovary (CHO) C1 cells and in transfected CHO (CK1.4) cells that contained an expression vector coding the Na⁺-Ca²⁺ exchanger sequence. 2. The [⁴⁵Ca²⁺] uptake assay, fura-2 fluorescence imaging and 2² and 2³ factorial orthogonal statistics provide comparative, direct, efficient, quantitative and transient methods to delineate the effects of such interactions on Ca²⁺ influx, Ca²⁺release and [Ca²⁺]i in C1 and CK1.4 cells. 3. In contrast to the control of either Na⁺-, Ca²⁺- or H₂O₂-free or CI cells, an elevated [⁴⁵Ca²⁺] uptake was induced by Ca²⁺, Na⁺ and H₂O₂ individually and in combination, intracellular Ca²⁺ release was activated by H₂O₂ and by combinations of either H₂O₂ and Na⁺, H₂O₂ and the Na⁺-Ca²⁺ exchanger, Na⁺ and the Na⁺-Ca²⁺ exchanger or by H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger and a rise in [Ca²⁺]i was triggered by H₂O₂, Na⁺ and a combination of Na⁺ and the Na⁺-Ca²⁺exchanger. 4. These results indicate that interactions between H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger stimulate intracellular Ca²⁺mobilization via Ca²⁺-induced Ca²⁺ release mechanisms, ATP-activated G-protein coupled P_2y-purinoceptor-sensitive pathways, Na⁺-Ca²⁺ exchanger-mediated Ca²⁺ influx and cation-π interaction (a strong non-covalent force between the cation and the π face of an aromatic structure in the transmembrane protein). 5. The present findings provide important clues for understanding Ca²⁺ signal transduction mechanisms from the plasma membrane to the endoplasmic reticulum.     

EFFECTS OF THE OPIOID PEPTIDES [MET5]ENKEPHALIN-ARG6-PHE7 AND [MET5]ENKEPHALIN-ARG6-GLY7-LEU8 ON CHOLINERGIC NEUROTRANSMISSION IN THE RABBIT ISOLATED ATRIA

1. The effect of the opioid peptides [Met5]enkephalin-Arg6-Phe7 (MEAP) and [Met5]enkephalin-Arg6-Gly7-Leu8 (MEAGL) were compared with those of [Leu5]enkephalin and [D-Ala2,Met5]enkephalinamide (DAME) on cholinergic neurotransmission in the rabbit isolated atria. 2. Rabbit isolated atria had a resting rate of 190 beats/min. In the presence of the beta-adrenoceptor antagonist propranolol (0.3 mumol/l), atria responded to electrical field stimulation with a cholinergically mediated negative chronotropic response. The opioid peptides had no effect on the resting rate, but inhibited the negative chronotropic response to field stimulation. The IC50 values for inhibiting the cholinergic responses were 1.4 mumol/l for [Leu5]enkephalin (LE), 1.4 mumol/l for MEAP, 1.3 mumol/l for MEAGL and 0.2 mumol/l for DAME. Responses of a similar magnitude to exogenous acetylcholine were unaffected. 3. Thus, MEAP, MEAGL and LE had similar potencies but DAME was about seven times more potent in inhibiting cholinergic neurotransmission in the rabbit isolated atria. The site of inhibition appears to be prejunctional.