雷公藤红素对抗过氧化氢诱导肌萎缩性侧索硬化症细胞模型氧化损伤的保护作用

本研究旨在探讨在H_2O_2诱导氧化应激损伤条件下,雷公藤红素对肌萎缩性侧索硬化症细胞模型SOD1~(G93A)NSC34的保护作用及其相关分子机制。用不同剂量H_2O_2、雷公藤红素处理表达人突变SOD1~(G93A)基因的NSC34细胞24 h后,CCK-8试剂检测细胞存活率;丙二醛试剂盒检测细胞内丙二醛水平;real-time PCR检测细胞谷氨酸半胱氨酸连接酶催化亚基(glutamatecysteine ligase catalytic subunit,GCLC)和谷胱甘肽硫转移酶(glutathione S-transferases,GST)的表达水平;Western blot检测药物处理后细胞内MEK/ERK和PI3K/Akt细胞信号通路的激活。结果显示,50 nmol/L雷公藤红素预处理可提高H_2O_2(10μmol/L)损伤后SOD1~(G93A)NSC34细胞的生存率,并使细胞内MDA生成减少,逆转H_2O_2诱导的SOD1~(G93A)NSC34细胞内谷胱甘肽合成相关酶GCLC和GST mRNA表达下调。雷公藤红素处理0.5 h、1 h分别激活SOD1~(G93A)NSC34细胞内MEK/ERK和PI3K/Akt信号通路达峰值,且MEK抑制剂PD98059和Akt抑制剂MK2206可阻断雷公藤红素对相关信号通路的激活效应。PD98059、MK2206预处理30 min均抑制雷公藤红素引起的SOD1~(G93A)NSC34细胞内GCLC和GST上调。以上研究结果提示,雷公藤红素对肌萎缩性侧索硬化症细胞模型SOD1~(G93A)NSC34细胞有抗氧化应激的保护作用,该神经保护作用与雷公藤红素调节SOD1~(G93A)NSC34细胞内谷胱甘肽合成相关酶类生成有关,细胞内MEK/ERK和PI3K/Akt信号通路参与此调节过程。     

雷公藤红素对过氧化氢诱导肌萎缩性侧索硬化症细胞模型氧化损伤的保护作用

本研究旨在探讨在H2O2诱导氧化应激损伤条件下,雷公藤红素对肌萎缩性侧索硬化症细胞模型SOD1G93ANSC34的保护作用及其相关分子机制。用不同剂量H2O2、雷公藤红素处理表达人突变SOD1G93A基因的NSC34细胞24h后,CCK-8试剂检测细胞存活率;丙二醛试剂盒检测细胞内丙二醛水平;real-time PCR检测细胞谷氨酸半胱氨酸连接酶催化亚基(glutamate-cysteine ligase catalytic subunit, GCLC)和谷胱甘肽硫转移酶(glutathione S-transferases, GST)的表达水平;Western blot检测药物处理后细胞内MEK/ERK和PI3K/Akt细胞信号通路的激活。结果显示,50 nmol/L雷公藤红素预处理可提高H2O2 (10 μmol/L)损伤后SOD1G93ANSC34细胞的生存率,并使细胞内MDA生成减少,逆转H2O2诱导的SOD1G93ANSC34细胞内谷胱甘肽合成相关酶GCLC和GST mRNA表达下调。雷公藤红素处理0.5 h、1 h分别激活SOD1G93ANSC34细胞内MEK/ERK和PI3K/Akt信号通路达峰值,且MEK抑制剂PD98059和Akt抑制剂MK2206可阻断雷公藤红素对相关信号通路的激活效应。PD98059、MK2206预处理30 min均抑制雷公藤红素引起的SOD1G93ANSC34细胞内GCLC和GST上调。以上研究结果提示,雷公藤红素对肌萎缩性侧索硬化症细胞模型SOD1G93ANSC34细胞有抗氧化应激的保护作用,该神经保护作用与雷公藤红素调节SOD1G93ANSC34细胞内谷胱甘肽合成相关酶类生成有关,细胞内MEK/ERK和PI3K/Akt信号通路参与此调节过程。     

花旗松素通过激活Nrf2/HO-1/HIF1α/Autophagy信号通路对H_2O_2所致H9C2细胞氧化应激保护作用的研究

氧化应激(oxidative stress,OS)是缺血性心肌病(ischemic cardiomyopathy,ICM)的主要发病机制之一,抗氧化应激损伤是防治缺血性心肌病的关键。为了探讨花旗松素(taxifolin,tax)对过氧化氢(hydrogen peroxide,H_2O_2)诱导的大鼠心肌细胞H9C2氧化应激的影响及其可能的分子机制,将培养的H9C2心肌细胞随机分为对照组(Control)、氧化应激组(H_2O_2)、tax预处理组(tax+H_2O_2)、tax单独处理组(tax)。通过观察细胞形态的改变,检测细胞内活性氧(reactive oxygen species,ROS)和丙二醛(malondialdehyde,MDA)的生成、自噬体自噬泡的形成,以及自噬(autophagy)相关蛋白质LC3 I/II、p62的表达,验证tax对氧化应激及自噬的影响。同时,通过检测Nrf2、HO-1、HIF1α的表达,研究可能存在的分子机制。研究发现tax可缓解H_2O_2诱导的H9C2细胞氧化应激,表现为细胞肥大形态缓解、ROS生成降低、MDA产生减少,而且Nrf2/HO-1/HIF1α蛋白的表达升高,自噬水平升高。实验结果表明:tax可能通过激活Nrf2/HO-1/HIF1α/Autophagy信号通路促进自噬及抗氧化应激,从而发挥心肌保护作用。     

连翘酯苷A通过Akt/Nrf2信号通路发挥抗脑缺血氧化损伤作用研究

目的:研究连翘酯苷A(Forsythiaside A,FA)对缺血再灌注引起的脑细胞损伤的保护作用及机制。方法:采用PC12细胞缺氧再复氧模型(OGD/R),细胞分组为正常组,模型组,FA处理组(1.25, 2.5和5μmol/L),测定细胞存活率、凋亡率、ROS、MDA以及抗氧化酶水平。采用Western blotting测定对Akt和Nrf2蛋白的影响,采用Akt抑制LY294002验证FA的调节作用。结果:FA能够有效抑制OGD/R引起的存活率下降和凋亡率增加,同时可以抑制细胞内ROS和MDA水平,升高细胞内抗氧化酶(SOD、GSH、GSH-Px和CAT)水平。FA处理能够增加Akt磷酸化水平以及Nrf2和其下游蛋白HO-1蛋白表达。进一步采用LY294002验证发现FA通过Akt调控Nrf2发挥抗氧化作用从而抑制脑细胞损伤。结论:FA能够抑制缺血再灌注引起的脑细胞损伤,其作用机制可能是通过促进Akt磷酸化,调控Nrf2下游抗氧蛋白酶表达,抑制氧化应激,从而保护脑细胞。     

荭草花醇提物对H_2O_2诱导的H9c2细胞氧化损伤的保护作用机制研究

研究荭草花醇提物对H9c2心肌细胞氧化损伤的保护作用机制。采用200μmol/L H_2O_2作用H9c2细胞0.5 h,建立H9c2细胞氧化损伤模型。将细胞分为正常对照组、H9c2细胞氧化损伤模型组、不同浓度荭草花醇提物(20、40、80μg/m L)预处理组。采用MTS法检测细胞存活率;生化试剂盒检测细胞乳酸脱氢酶(LDH)释放量,细胞内丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活力;Western blot测定cleavedcaspase-3、Bcl-2、Bax、p-AKT和AKT的表达。与模型组比较,荭草花醇提物能明显增加心肌细胞存活率,降低LDH释放量和MDA含量,提高SOD及CAT活性,并呈剂量依赖性抑制H_2O_2诱导的氧化应激损伤。荭草花醇提物下调cleaved caspase-3和Bax的蛋白水平,上调Bcl-2的表达,减少心肌细胞凋亡;增加细胞中p-AKT的表达,且这种表达可被PI3Ks抑制剂LY294002抵消。表明荭草花醇提物可减轻H_2O_2诱导的H9c2心肌细胞氧化应激损伤,其机制可能与减少细胞凋亡,平衡氧化应激产物有关,且部分依赖于磷脂酰肌醇3-激酶(PI3K/Akt)通路。     

姜黄素对H_2O_2诱导的HT29细胞氧化损伤的保护作用及机制研究

研究姜黄素对H_2O_2诱导HT29细胞氧化应激的保护作用及其可能的分子机制。分别采用低、中、高浓度姜黄素处理H_2O_2诱导的HT29细胞氧化损伤模型,并设置H_2O_2模型组和正常对照组;MTT法确定H_2O_2最佳损伤浓度和时间及姜黄素(2.5、5、10μmol/L)对H_2O_2诱导的HT29细胞活性的影响;Annexin V/PI双标记流式细胞术检测细胞凋亡情况;PI染色流式细胞术检测细胞周期变化;DCFH-DA荧光探针检测细胞内活性氧(ROS);JC-1染色检测细胞线粒体膜电位;比色法测定乳酸脱氢酶(LDH)释放量,以及丙二醛(MDA)、超氧化物歧化酶(SOD)、caspase-3和caspase-9的水平。结果显示姜黄素组(2.5、5、10μmol/L)明显提高H_2O_2诱导的HT29细胞的存活率(P0.05,P0.01);与H_2O_2模型组相比,姜黄素组细胞凋亡率降低(P0.01),增殖指数增高(P0.05,P0.01),LDH释放量和细胞内ROS降低(P0.05,P0.01),线粒体膜电位上升(P0.01),SOD活力增加(P0.01),MDA降低(P0.01),caspase-3和caspase-9活性增强(P0.01),并呈剂量-效应关系。结果表明姜黄素在一定剂量范围内对H_2O_2诱导的HT29细胞氧化损伤具有较好的保护作用,该作用可能与清除ROS,减轻DNA氧化损伤,抑制线粒体通路介导的细胞凋亡有关。     

Fisetin对H_2O_2诱导细胞内ROS的清除作用及机制探讨

活性氧(reactive oxygen species, ROS)在非酒精性脂肪肝、心血管疾病、癌症、糖尿病等疾病发生发展的过程中具有重要作用。HepG2细胞是评价抗氧化剂对活细胞氧化损伤保护作用的常用细胞模型。为了探讨非瑟酮(fisetin)对H_2O_2诱导细胞内ROS的清除作用及其机制,将HepG2细胞随机分为空白对照组(control)、溶剂对照组(solvent control)、H_2O_2模型组(H_2O_2model group)、fisetin干预组(fisetin+H_2O_2)、fisetin单独处理组(fisetin),检测不同干预组细胞存活率大小及细胞内ROS水平,同时检测核因子E2相关因子2 (nuclear factor erythroid 2-related factor 2, Nrf2)、Kelch样ECH相关蛋白1 (Kelch-like ECH-associated protein 1, Keap1)及Ⅱ相酶血红素氧合酶-1 (heme oxygenase-1, HO-1)、谷氨酰半胱氨酸连接酶催化亚基(glutamate-cysteine ligase catalytic subunit,GCLC)、谷氨酰半胱氨酸连接酶修饰亚基(glutamate-cysteine ligase modifier subunit, GCLM)、醌氧化还原酶1(NAD(P)H quinone oxidoreductase 1, NQO1)的表达。此外,通过构建Nrf2敲低细胞系,进一步明确Nrf2在fisetin清除ROS过程中的作用。研究发现,与H_2O_2模型组相比, fisetin干预组细胞存活率显著上升; fisetin可抑制由H_2O_2引起的HepG2细胞内ROS的增加,上调Nrf2、HO-1蛋白表达,并下调Keap1蛋白表达; Nrf2稳定敲低后,细胞内ROS水平增加。实验结果表明, fisetin可能通过激活Keap1/Nrf2/抗氧化反应元件(antioxidant response element, ARE)通路诱导HO-1的表达,从而在抗氧化损伤过程中发挥细胞保护作用。     

山楂酸对H_2O_2诱导的BRL-3A细胞氧化损伤及p38和Nrf2/HO-1通路的影响

该文研究了山楂酸对H_2O_2诱导的BRL-3A肝细胞氧化损伤的保护作用及其机制。采用MTT法检测细胞活力,DCFH-DA荧光探针法测定细胞的ROS水平,微量酶标法测定细胞LDH、SOD、CAT的活力和GSH、MDA含量;反转录PCR测定细胞Nrf2、HO-1和p38的mRNA表达水平;Western blot检测Nrf2、HO-1和p-p38的蛋白表达水平。结果显示,山楂酸可改善H_2O_2导致的BRL-3A细胞活力下降,降低ROS水平和LDH渗漏,提高SOD、CAT的活性和GSH含量,降低MDA的水平。此外,山楂酸可促进Nrf2的核转位,提高HO-1的mRNA和蛋白表达水平,抑制p38的磷酸化水平。这些结果表明,山楂酸对H_2O_2诱导的BRL-3A细胞的氧化损伤有保护作用,其机制与促进Nrf2的核转位、上调HO-1的表达和抑制p38的磷酸化水平可能相关。     

Nrf2/ARE通路相关因子在脂肪变性HepG2细胞中的表达及其意义

目的:探讨建立一种新型的脂肪变性人肝癌细胞(Hep G2)模型,观察核因子E2相关因子2(Nrf2)/抗氧化反应元件(ARE)通路相关因子在脂肪变性Hep G2细胞中的表达及其意义。方法:Hep G2细胞给予含25%的胎牛血清、0.1%医用脂肪乳和0.1 mmol/L游离脂肪酸(FFA)的DMEM培养基分阶段诱导后,建立脂肪变性Hep G2细胞模型,并设置对照组。模型成功后,以油红O染色观察细胞内脂滴形成状况,并用全自动生化仪检测细胞内甘油三酯(TG)含量;采用流式细胞仪测定细胞内活性氧(ROS)的含量,采用生物试剂盒检测细胞内一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)含量及活性的变化;运用Western blot法检测各组细胞Nrf2、血红素氧化酶-1(HO-1)和醌氧化还原酶1(NQO1)蛋白的表达。结果:与对照组比较,模型组油红O染色可见细胞内橘红色脂滴大量形成,TG、ROS、NO、MDA含量水平明显增高(P0.05,P0.01),SOD、GSHPx活性明显下降(P0.01),Nrf2、HO-1和NQO1蛋白表达均显著增高(P0.05,P0.01)。结论:本模型可以成功诱导Hep G2细胞发生脂肪变性和氧化应激损伤状态;Nrf2/ARE通路下游相关因子发生激活可能与脂肪变性Hep G2细胞氧化应激的过度反应有关。     

银杏内酯B 对星形胶质细胞氧化损伤的保护作用

目的:探讨银杏内酯B对过氧化氢(H_2O_2)诱导的星形胶质细胞损伤的保护作用及可能机制。方法:星形胶质细胞传代培养,分为阴性对照组(以正常培养液培养),氧化损伤组(100μmol·L~(-1)的H_2O_2作用12 h),银杏内酯B低剂量组(1×10~(-6) mol·L~(-1)银杏内酯B孵育24 h后,加入H_2O_2作用12 h)和银杏内酯B高剂量组(1×10~(-4) mol·L~(-1)银杏内酯B孵育24 h后,加入H_2O_2作用12 h),MTT比色法检测细胞存活率,流式细胞仪检测细胞活性氧(ROS)水平,分光光度计检测上清液中超氧化物歧化酶(SOD)、如谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)的含量。结果:银杏内酯B能抑制氧化损伤引起的细胞活性的下降,降低星形胶质细胞内ROS的生成,促进SOD、GSH-Px水平的升高及MDA水平的下降。结论:银杏内酯B通过提高细胞内SOD、GSH-Px含量,降低细胞内MDA含量发挥其较强的抗氧化作用,从而为其用于治疗神经系统疾病提供可靠的实验依据。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various