缺氧应激对肝癌细胞代谢信号通路的调节作用

通过实验阐明在缺氧条件下糖酵解相关基因表达的变化规律及对肿瘤细胞和正常细胞增殖的影响,并探索活性氧(ROS)介导肝癌细胞代谢途径及对相关基因表达和酶活性的调节作用.以SMMC-7721人肝癌细胞和L02正常肝细胞作为研究对象,分别在单纯缺氧及加葡萄糖缺氧条件下,观察细胞生长,并检测糖代谢关键酶:丙酮酸激酶(pyruvate-kinase,PK)、己糖激酶(hexokinase,HK)、琥珀酸脱氢酶(succinic dehydrogenase,SDH)、异柠檬酸脱氢酶(isocitric dehydrogenase,IDH)mRNA表达水平和乳酸脱氢酶(lactate dehydrogenase,LDH)活性.还检测了pkb基因及缺氧诱导因子hif-1的表达.实验结果说明:a.肿瘤细胞较正常细胞具有更强的缺氧耐受性;b.缺氧条件下,糖酵解途径的增强是保证肿瘤细胞能快速增殖的机制之一;c.ROS通过HIF-1介导了糖代谢通路相关酶的基因表达,参与肝癌细胞缺氧信号通路调节,用抗氧化剂干预可以降低肿瘤细胞的缺氧耐受能力.     

α-硫辛酸对6-羟多巴胺诱导的PC12细胞凋亡的影响

实验运用PC12细胞系研究6-羟多巴胺的细胞毒性作用以及α-硫辛酸抗6-羟多巴胺毒性的作用及其机制.用MTT法测定显示6-OHDA使细胞存活率降低至56.8%,细胞突起变短、胞质浓缩、核质深染,细胞贴壁能力下降,胞膜损伤.原位末端dUTP标记法(TUNEL)显示阳性标记细胞,表明6-OHDA引起PC12细胞产生坏死和凋亡.流式细胞仪分析表明6-OHDA作用后凋亡细胞比例达20.09%.运用α-硫辛酸预处理后,能明显预防6-OHDA的毒性作用,可使细胞存活率上升,凋亡细胞比例降低至3.09%,α-硫辛酸的作用与提高细胞内超氧化物歧化酶(SOD)活力和还原型谷胱甘肽(GSH)含量有关.     

丁咯地尔和α- 硫辛酸对糖尿病大鼠肾功能的保护作用研究

目的:研究丁咯地尔和α-硫辛酸(ALA)对糖尿病(DM)大鼠肾功能的保护作用。方法:雄性SD大鼠用链脲佐菌素(60 mg/kg)腹腔注射诱导DM。大鼠随机分为健康组(NC)、DM组(DMC)、DM+ALA组(ALA组)、DM+丁咯地尔组(丁咯地尔组)。ALA组和丁咯地尔组每天给予ALA 100 mg/kg灌胃和丁咯地尔(0.1 g/kg)腹腔注射,NC组和DMC组大鼠给予等量生理盐水每日灌胃。干预4周后,测观察治疗后大鼠血糖、尿素氮、血肌苷,内生肌苷清除率、24小时尿蛋白排泄率,比色法检测血清抗氧化酶和丙二醛(MDA)含量。结果:①丁咯地尔和α-硫辛酸降低糖尿病大鼠的尿素氮、血肌苷、24h尿白蛋白排泄率、丙二醛,增加超氧化物歧化酶②两种药物联合用药具有协同作用。结论:丁咯地尔和ALA可能通过抑制机体氧化应激水平,减低早期DM大鼠肾脏损害。     

丁咯地尔和α-硫辛酸对糖尿病大鼠肾功能的保护作用研究

目的：研究丁咯地尔和α-硫辛酸（ALA）对糖尿病（DM）大鼠肾功能的保护作用。方法：雄性SD大鼠用链脲佐菌素（60mg/kg）腹腔注射诱导DM。大鼠随机分为健康组（NC）、DM组（DMC）、DM＋ALA组（ALA组）、DM＋丁咯地尔组（丁咯地尔组）。ALA组和丁咯地尔组每天给予ALA100mg／kg灌胃和丁咯地尔（0．1g／kg）腹腔注射,NC组和DMC组大鼠给予等量生理盐水每日灌胃。干预4周后,测观察治疗后大鼠血糖、尿素氮、血肌苷,内生肌苷清除率、24小时尿蛋白排泄率,比色法检测血清抗氧化酶和丙二醛（MDA）含量。结果：①丁咯地尔和α-硫辛酸降低糖尿病大鼠的尿素氮、血肌苷、24h尿白蛋白排泄率、丙二醛,增加超氧化物歧化酶②两种药物联合用药具有协同作用。结论：丁咯地尔和ALA可能通过抑制机体氧化应激水平,减低早期DM大鼠肾脏损害。     

高氧对雄激素敏感的前列腺癌细胞移植瘤生长及其缺氧诱导因子-1α表达的影响

目的:探讨高氧对雄激素敏感的前列腺癌细胞移植瘤生长及其缺氧诱导因子-1α表达的影响。方法:将前列腺癌前列腺淋巴结癌(LNCa P)细胞接种于36只Foxn1小鼠的双侧腹,并将其随机放置于含氧量不同的气室中并分组如下:缺氧组11例,常氧组16例,高氧组9例。处理28天后进行称重,麻醉处死,从左心室取血样;分离出移植瘤并进行称重。采用Western blotting、免疫荧光分析、血红蛋白测定的方法对各组移植瘤生长、血管生成及血管化、缺氧诱导因子-1(HIF-1α)表达以及细胞信号转导因子表达进行检测。结果:缺氧组的移植瘤生长较常氧组快(P0.05);高氧组移植瘤生长与常氧组相比差异不具有统计学意义(P0.05)。高氧组移植瘤的HIF-1α、血管内皮生长因子(VEGF)和血管内皮生长因子受体2(VEGF-R2)表达均较常氧组高,而缺氧组移植瘤的HIF-1α表达与常氧组基本相似。缺氧组移植瘤的血[HB]增长率(175%)高于常氧组(45%)。高氧组的Nrf2的表达水平较常氧组明显增加(P0.05)。结论:体内高氧诱导HIF-1α在LNCa P肿瘤高表达的同时,不会加快肿瘤的生长。     

多组学分析揭示Grb2介导α-硫辛酸抑制肝癌细胞增殖研究

目的:为更深入了解α-硫辛酸如何影响复杂信号通路间的相互作用抑制细胞增殖。方法:我们凭借RNA-Seq与同位素相对标记与绝对定量技术,对α-LA处理24 h HepG2细胞在转录和蛋白表达水平的变化差异进行分析,并借助实时定量PCR免疫印迹技术对组学数据进行了鉴定。结果:转录组学提示共有4,446个基因(2,097个基因表达下调,2,349个基因表达上调)的表达在α-LA处理24 h后呈现显著性改变。GO分析提示,编码肿瘤相关细胞膜蛋白的基因是受α-LA影响最为显著的一类mRNA;蛋白质组学进一步提示Grb2可能是受α-LA调控的膜受体信号通路中关键的靶分子。结论:α-LA抑制HCC细胞增殖是通过下调Grb2介导的相关通路而实现。     

α-硫辛酸对糖尿病肾病患者氧化应激, Hcy, CysC的影响

目的:探讨α-硫辛酸对糖尿病肾病患者的疗效及对氧化应激、同型半胱氨酸(homocysteine,Hcy)、血清胱抑素C(cystatin C,CysC)的影响。方法:将82例于我院进行治疗的2型糖尿病肾病患者随机分为观察组和对照组,对照组患者接受常规治疗,观察组患者在对照组的基础上加用α-硫辛酸。治疗时间均为2周。观察两组治疗效果并比较两组患者治疗前、后氧化应激指标超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)及Hcy、CysC水平变化。结果:治疗后,观察组氧化应激指标SOD水平均较治疗前显著升高(P0.05),MDA水平均较治疗前显著降低(P0.05),对照组氧化应激指标SOD及MDA水平与治疗前无明显差异(P0.05),两组治疗后SOD及MDA水平差异显著(P0.05);治疗后,观察组Hcy、CysC水平较治疗前显著降低(P0.05),对照组Hcy、CysC水平与治疗前无明显差异(P0.05),两组治疗后Hcy、CysC水平差异显著(P0.05)。结论:α-硫辛酸可缓解糖尿病肾病患者氧化应激状态,降低Hcy、CysC水平,改善患者肾功能。     

α-硫辛酸对2型糖尿病早期肾病的保护作用研究

目的：探讨注射用α-硫辛酸对2型糖尿病早期肾病（DN）的保护作用。方法：将56例2型糖尿病早期肾病患者随机分为治疗组28例,采用注射α-硫辛酸加常规治疗;对照组28例,仅给予常规治疗。治疗前后测定尿微量白蛋白排泄率（UAER）、超氧化物歧化酶（SOD）、／丙二醛（MDA）、一氧化氮（NO）水平。结果：与治疗前比较,治疗组UAER及MDA均显著降低（P〈0．05）,SCr、SOD及NO显著升高（P〈0．05）。对照组SCr、UAER、SOD、MDA及NO与治疗前比较差异无统计学意义（P〉0．05）。结论：注射用α-硫辛酸能减少2型糖尿病肾病患者尿微量白蛋白的排泄,对早期肾病具有保护作用。     

活性氧和线粒体ATP敏感钾通道介导肿瘤坏死因子α对缺氧/复氧心肌的保护作用

在培养的乳鼠心肌细胞上,研究肿瘤坏死因子α(TNF-α)对缺氧/复氧损伤心肌的保护作用的机制。结果发现：(1)用TNF-α(10—500U／ml)预处理,缺氧/复氧后心肌细胞内锰超氧化物歧化酶(Mn-SOD)活性增高、乳酸脱氢酶(LDH)释放量减少(P＜0．05);(2)用抗氧化剂N-乙酰半既氨酸(NAC,1mmol/L)、抗霉素A(antimycin A,50μmol/L)、2-巯基丙酰氨基乙酸(2-MPG,400μmol/L)和铜／锌超氧化物歧化酸(Cu/Zn,SOD)抑制剂二乙基二硫代氨基甲酸盐(DDC,100nmol/L)预处理,可取消TNF-α的抑制缺氧/复氧心肌细胞LDH释放和诱导Mn-SOD活性增高的作用;(3)mitoKATP通道抑制剂5-羟基癸酸(5-HD)预处理可阻断TNF-α对缺氧/复氧心肌细胞的保护作用;选择性mitoKATP通道开放剂diazoxide(50μmol/L)预处理可减少复氧后心肌细胞LDH的释放(P＜0．01),其作用可被5-HD(100μmol/L)和NAC所抑制。上述结果表明,活性氧和线粒体ATP敏感钾通道参与介导TNF-α对缺氧/复氧损伤的心肌保护作用。     

华蟾素对MDA - MB -231细胞线粒体膜电位及活性氧的影响

目的:研究华蟾素诱导乳腺癌MDA - MB - 231细胞凋亡过程中,细胞内活性氧(ROS)及线粒体膜电位(△Ψm)的变化,探讨华蟾素对乳腺癌细胞的作用机制.方法:用不同浓度的华蟾素作用于MDA - MB - 231细胞24h后,分别用荧光探针罗丹明123和荧光探针DCFH-DA进行荧光染色,用流式细胞仪检测细胞内线粒体膜电位和活性氧的变化.结果:不同浓度的华蟾素作用于MDA - MB - 231细胞后,随着药物浓度的增加(0、12.5、25、37.5、50μg/ml),细胞内的ROS水平显著升高,荧光强度从3 609±24上升为6 263±35;同时,线粒体膜电位(△Ψm)显著下降,荧光强度从242±6降低到173±4.结论:华蟾素作用细胞后,使得细胞内活性氧水平显著升高,同时,线粒体膜电位显著下降,推测华蟾素对MDA - MB - 231细胞通过线粒体途径诱发细胞凋亡.     

Inhibitory Effect of Ascorbic Acid on the Proliferation and Invasion of Hepatoma Cells in Culture

Effect of ascorbic acid (AsA) on the proliferation and invasion of rat ascites hepatoma AH109A cells was investigated by measuring [³H]thymidine incorporation into acid-insoluble fraction of the cells and by co-culturing the hepatoma cells with rat mesentery-derived mesothelial cells, respectively. AsA suppressed the invasion of AH109A cells in a dose-dependent manner at concentrations of 62.5–500 μM, while it inhibited the proliferation of the cells at higher concentrations of 250 and 500 μM. Hepatoma cells previously cultured with hypoxanthine (HX) and xanthine oxidase (XO) or with hydrogen peroxide showed increased invasive activities. AsA suppressed the reactive oxygen species-potentiated invasive capacity by simultaneously treating AH109A cells with AsA, HX and XO or with AsA and hydrogen peroxide. Furthermore, AsA reduced the intracellular peroxide levels in AH109A cells. These results suggest that the antioxidative property of AsA may be involved in its anti-invasive action on hepatoma cells.     

低溶氧量对怀头鲇呼吸代谢耗氧率的影响

在 ( 2 2± 1 )℃下 ,测定了怀头鲇在不同低溶氧量 (DO)时的摄氧量 (VO2 )和呼吸参数。结果表明 ,随着吸入水氧分压 (PiO2 )的降低 ,呼吸频率 (Fr)和VO2 略增 ;鳃通量 (Vg)和呼吸量 (Vb)显著增加 ;而氧利用率 (EO2 )则显著降低。在通常氧含量 ( 7 4 1mg L)时 ,怀头鲇呼吸代谢耗氧率 (Cr)仅为 2 6 3% ,但在严重缺氧 ( 2 5 8mg L)时 ,Cr 则增至 2 4 6 0 %。可见 ,低氧环境将严重抑制怀头鲇的生长。     

The Contribution of Mitochondrial Respiratory Complexes to the Production of Reactive Oxygen Species

This work was focused on distinguishing the contribution of mitochondrial redox complexesto the production of reactive oxygen species (ROS) during cellular respiration. We were ableto accurately measure, for the first time, the basal production of ROS under uncoupled conditionsby using a very sensitive method, based on the fluorescent probe dichlorodihydrofluoresceindiacetate. The method also enabled the detection of the ROS generated by the oxidation ofthe endogenous substrates in the mitochondrial preparations and could be applied to bothmitochondria and live cells. Contrary to the commonly accepted view that complex III(ubiquinol:cytochrome c reductase) is the major contributor to mitochondrial ROS production, wefound that complex I (NADH-ubiquinone reductase) and complex II (succinate-ubiquinonereductase) are the predominant generators of ROS during prolonged respiration under uncoupledconditions. Complex II, in particular, appears to contribute to the basal production of ROSin cells.     

Involvement of Reactive Oxygen Species in Plant Mitochondrial Response to Low-Temperature Stress

The review presents data for the generation of the reactive oxygen species (ROS) in mitochondria during low-temperature stress. The relation of lipid peroxidation processes in membranes to the induction of low-temperature stress is demonstrated. The data for the involvement of the mitochondrial uncoupling proteins and the processes of uncoupling oxidation and phosphorylation in the regulation of mitochondrial ROS formation during low-temperature stress are considered.     

Mitochondrial reticulum network dynamics in relation to oxidative stress, redox regulation, and hypoxia

A single mitochondrial network in the cell undergoes constant fission and fusion primarily depending on the local GTP gradients and the mitochondrial energetics. Here we overview the main properties and regulation of pro-fusion and pro-fission mitodynamins, i.e. dynamins-related GTPases responsible for mitochondrial shape-forming, such as pro-fusion mitofusins MFN1, MFN2, and the inner membrane-residing long OPA1 isoforms, and pro-fission mitodynamins FIS1, MFF, and DRP1 multimers required for scission. Notably, the OPA1 cleavage into non-functional short isoforms at a diminished ATP level (collapsed membrane potential) and the DRP1 recruitment upon phosphorylation by various kinases are overviewed. Possible responses of mitodynamins to the oxidative stress, hypoxia, and concomitant mtDNA mutations are also discussed. We hypothesize that the increased GTP formation within the Krebs cycle followed by the GTP export via the ADP/ATP carrier shift the balance between fission and fusion towards fusion by activating the GTPase domain of OPA1 located in the peripheral intermembrane space (PIMS). Since the protein milieu of PIMS is kept at the prevailing oxidized redox potential by the TOM, MIA40 and ALR/Erv1 import-redox trapping system, redox regulations shift the protein environment of PIMS to a more reduced state due to the higher substrate load and increased respiration. A higher cytochrome c turnover rate may prevent electron transfer from ALR/Erv1 to cytochrome c. Nevertheless, the putative links between the mitodynamin responses, mitochondrial morphology and the changes in the mitochondrial bioenergetics, superoxide production, and hypoxia are yet to be elucidated, including the precise basis for signaling by the mitochondrion-derived vesicles.     

Chlorogenic Acid Metabolism: The Evolution and Roles in Plant Response to Abiotic Stress

During the evolution, plants acquired the ability to synthesize different phenylpropanoid compounds like chlorogenic acid (CGA), which plays vital roles in resistance mechanisms to abiotic stresses. These environmental factors, including heavy metal, cold, heat, ultraviolet (UV) light, drought, and salinity affect the plant physiological processes, resulting in massive losses of agriculture production. As plants evolve from green algae to bryophytes, ferns, gymnosperms and angiosperms, phenylpropanoids are produced and accumulated in different tissues, giving the plant the capacity to counteract the harmful effects of the adverse environments. Studies have been performed on the metabolic evolution of rosmarinic acid, flavonoids and lignin, showing that the biosynthesis of phenylpropanoids begins in green algae until the emersion of genes found in angiosperms; however, the evolution of the CGA pathway has not yet been reviewed. We hypothesize that CGA could also be synthesized from algae to angiosperms. In the present review, the evolutionary analysis of CGA pathway and the function of this compound in plant tolerance to abiotic stresses are summarized. Bioinformatics analyzes were carried out on CGA-related genes across 37 plant species and revealed that the metabolic pathway starts in algae and gradually increases until it becomes complete in angiosperms. The key genes exhibited different expression patterns in stress and plant tissues. Interestingly, some genes accumulated rapidly during evolution and were more sensitive to environmental stresses, while others appeared only later in angiosperms. Further studies are needed to better understand the evolution of the CGA metabolic pathway in plants under environmentally stressed conditions.     

植酸对月季切花瓶插寿命的影响

用0.13％和0.013％植酸对月季切花进行处理,探讨了植酸对月季切花瓶插寿命及衰老过程中一些生理生化指标的影响.结果表明,013％和0.013％植酸处理的切花,瓶插寿命分别延长了2.3 d和1.4d.植酸处理抑制了O-2含量的增加和POD活性的提高,从而减轻了O-2对植物细胞的伤害即抑制丙二醛含量增加,同时抑制了可溶...     

Effect of Hypoxia and Dopamine on Arachidonic Acid Metabolism in Superior Cervical Ganglion

Superior cervical ganglion (SCG) may play a modulatory role on ventilatory control through its efferent sympathetic fibres, which innervate cells in the carotid bodies. In this study the in vivo effect of acute hypoxia versus normoxia on arachidonic acid (AA) metabolism was investigated in cat SCG. Using SCG homogenate AA was incorporated into glycerolipids of normoxic SCG in the following order: neutral glycerolipids > phosphatidylcholine (PtdCh) > phosphatidylinositol (PtdIns) > phosphatidylethanolamine (PtdE) > phosphatidylserine (PtdS) > and phosphatidic acid (PA). In vivo hypoxic treatment caused a significant decrease in incorporation of [1-¹⁴C]AA into PtdIns. Hypoxia had no significant effect on the level of AA radioactivity in diacylglycerol (DAG) as compared to control but significantly enhanced the level of arachidonoyl-CoA (AA-CoA) radioactivity. It was observed that dopamine (DA) one of the most important neurotransmitter in SCG decreases AA uptake into phospholipids of normoxic SCG. In normoxic SCG, DA significantly decreased, AA incorporation into PtdCh, PtdIns and DAG. Moreover, DA decreased the level of AA-CoA radioactivity. Hypoxia and dopamine has no effect on AA metabolism in medulla oblongata isolated from the same animals. These results indicate that arachidonic acid metabolism in SCG is sensitive to hypoxia and dopamine action. Moreover, these results indicate that hypoxia inhibits selectively AA incorporation on the level of acylCoA-lysophosphatidylinositol-acyltransferase.     

Mitochondrial Enzymes and Endoplasmic Reticulum Calcium Stores as Targets of Oxidative Stress in Neurodegenerative Diseases

Considerable evidence indicates that oxidative stress accompanies age-related neurodegenerative diseases. Specific mechanisms by which oxidative stress leads to neurodegeneration are unknown. Two targets of oxidative stress that are known to change in neurodegenerative diseases are the mitochondrial enzyme alpha-ketoglutarate dehydrogenase complex (KGDHC) and endoplasmic reticulum calcium stores. KGDHC activities are diminished in all common neurodegenerative diseases and the changes are particularly well documented in Alzheimer's disease (AD). A second change that occurs in cells from AD patients is an exaggerated endoplasmic reticulum calcium store [i.e., bombesin-releasable calcium stores (BRCS)]. H(2)O(2), a general oxidant, changes both variables in the same direction as occurs in disease. Other oxidants selectively alter these variables. Various antioxidants were used to help define the critical oxidant species that modifies these responses. All of the antioxidants diminish the oxidant-induced carboxy-dichlorofluorescein (cDCF) detectable reactive oxygen species (ROS), but have diverse actions on these cellular processes. For example, alpha-keto-beta-methyl-n-valeric acid (KMV) diminishes the H(2)O(2) effects on BRCS, while trolox and DMSO exaggerate the response. Acute trolox treatment does not alter H(2)O(2)-induced changes in KGDHC, whereas chronic treatment with trolox increases KGDHC almost threefold. The results suggest that KGDHC and BRCS provide targets by which oxidative stress may induce neurodegeneration and a useful tool for selecting antioxidants for reversing age-related neurodegeneration.     

低氧胁迫对黄瓜幼苗根系无氧呼吸酶和抗氧化酶活性的影响

对两个抗低氧胁迫能力不同的黄瓜品种进行营养液水培,研究了低氧胁迫下植株根系中无氧呼吸酶和抗氧化酶活性的变化。结果表明,低氧胁迫下,黄瓜植株生长受到抑制,鲜重和干重显著降低,根系中蛋白质含量降低,而根系中乳酸脱氢酶（LDH）、丙酮酸脱羧酶（PDC）、乙醇脱氢酶（ADH）、超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性在低氧胁迫下显著提高,且提高的幅度与品种抗低氧胁迫能力的强弱有关,与“中农8号”相比,抗低氧性胁迫能力较强的“绿霸春四号”根系内LDH活性增幅较小,而ADH、PDC、SOD、POD和CAT活性增幅较大。说明较高的ADH、PDC、SOD、POD、CAT活性和较低的LDH活性有利于增强幼苗植株抗低氧胁迫的能力。