线粒体:急性肾损伤治疗的新靶标

线粒体是细胞的"能量工厂",是合成三磷酸腺苷的主要场所,为细胞的生命活动提供能量来源。正常肾单位依赖线粒体生成的ATP以维持对肾小球滤过液体的重吸收。线粒体对各种损伤性刺激敏感,线粒体功能障碍是急性肾损伤(AKI)的早期事件,在AKI的发生与进展中发挥重要作用,维持线粒体结构和功能的完整,有助于防治AKI的发生发展。在缺血再灌注大鼠肾脏组织中MPTP开放增加、ROS产生增加、ATP下降,而缺血后处理的肾组织MPTP开放减少、损伤较轻。应用线粒体靶向的多肽SS-31可抑制ROS产生、MPTP开放,对肾损伤起保护作用。免疫抑制剂环孢素A是一种m PTP的抑制剂,亦可抑制MPTP开放,从而发挥肾保护作用。线粒体形态学的改变也是缺血再灌注肾损伤的重要机制之一。将线粒体分裂主要的调控因子Drp1抑制可以显著抑制缺血再灌注诱导的线粒体分裂,并抑制小管细胞凋亡,减轻肾损伤。在体外培养的猪肾小管上皮细胞中,顺铂处理后出现激活线粒体信号通路包括开放MPTP、释放细胞色素c、活化胱天蛋白酶等,诱导细胞损伤。应用线粒体主要的抗氧化蛋白MnSOD的类似物MnTBAP可阻断顺铂诱导的线粒体活性氧产生以及细胞损伤。通过调控MnSOD信号可减少顺铂诱导的肾组织氧化应激以及凋亡。顺铂刺激亦可诱导肾小管上皮细胞自噬及线粒体自噬,促进线粒体自噬能够保护线粒体功能进而减轻顺铂诱导的肾小管上皮细胞损伤,抑制线粒体自噬损伤线粒体功能进一步加重顺铂诱导的肾小管上皮细胞损伤。随着对线粒体功能障碍在AKI发病机制的研究不断深入,多种靶向线粒体的药物被证实可通过调节线粒体的功能对抗肾脏损伤,这些药物包括线粒体分裂的抑制剂、MPTP孔抑制剂、线粒体抗氧化蛋白的类似物、线粒体靶向的醌类化合物以及多肽等,部分药物已经在临床试验中应用并验证,然而将其应用于临床急性肾损伤的防治仍需要更多以及更深入的工作。     

线粒体与心肌缺血/再灌注损伤

心肌缺血/再灌注损伤会破坏线粒体稳态平衡引起功能紊乱,如线粒体ATP合成减少、ROS生成增加、Ca2+超载、膜通透性增加、线粒体片段化等,这些事件相互作用从多条途径参与I/R过程,是心肌I/R损伤的重要原因。对I/R中线粒体病理变化及I/R损伤线粒体保护途径的最新研究进展进行综述,为基于线粒体途径的心血管疾病药物防治研究提供参考。     

线粒体功能损伤与胰岛素抵抗

胰岛素抵抗在肥胖、代谢综合症、心血管类疾病和2型糖尿病及其并发症等疾病的病理病程中起了重要的作用。近年来,研究发现线粒体功能损伤与胰岛素抵抗有着密切的联系。一些遗传因素、老化现象、ROS生成的增多、线粒体生物合成降低或一些线粒体相关蛋白变化,都可能损伤线粒体功能,而这些因素也都是诱发胰岛素抵抗的主要诱因。了解线粒体损伤与胰岛素抵抗的关系将为胰岛素抵抗的研究和治疗提供新的思路。该文将从遗传因素、老化、ROS、生物合成、UCP、Sirt3等可影响线粒体功能的几个方面阐述线粒体功能损伤与胰岛素抵抗的关系,并介绍胰岛素抵抗治疗中与线粒体相关的药物作用机制。     

线粒体DNA损伤与视网膜色素上皮细胞关系的研究进展

线粒体 DNA （mtDNA） 是线粒体内具有遗传效应的双股闭环 DNA 分子, 对细胞及其功能具有重要作用。视网膜色素上皮 （RPE） 细胞活动亦由大量线粒体参与。因 RPE 细胞代谢活跃, 当发生氧化应激时可引起线粒体及 mtDNA 损伤; 当线粒体及 mtDNA 损伤无法及时修复而使损伤积累, 可引起 RPE 及线粒体功能障碍, 并诱发启动细胞凋亡, 进而引发某些眼病, 如年龄相关性黄斑变性等。现就 mtDNA 与 RPE 细胞的功能关系、 mtDNA 损伤修复及检测方法作一综述。     

海洛因对人 T淋巴细胞线粒体产能代谢的影响

目的：研究不同海洛因吸食年限者T淋巴细胞线粒体功能,探讨海洛因对人 T淋巴细胞线粒体产能代谢的影响。方法采集不同海洛因吸食年限人员外周血,提取T淋巴细胞;MTT法检测T淋巴细胞增殖活性;流式细胞仪检测T淋巴细胞凋亡情况;荧光分光光度法检测细胞内ROS、三磷酸腺苷（ATP）含量。结果随着海洛因吸食年限的增加,T淋巴细胞增殖活性逐渐下降,细胞凋亡逐渐增加,与此同时,细胞内ROS含量增高、细胞线粒体产能逐渐减少。结论长时间吸食海洛因可能导致机体损伤,其机制可能与海洛因对人 T 淋巴细胞线粒体功能的影响有关。     

扇贝多肽对UVA损伤HaCaT细胞UCP2表达及线粒体功能的影响

目的探究紫外线A(ultraviolet A,UVA)损伤对HaCaT角质形成细胞线粒体解偶联蛋白2(uncoupling protein2,UCP2)表达的影响以及扇贝多肽(polypeptide from Chlamysfarreri,PCF)的调节作用,并研究PCF对UVA损伤HaCaT细胞线粒体功能的保护作用。方法复制8 J.cm-2 UVA辐射损伤HaCaT角质形成细胞模型,免疫印迹法检测UVA损伤后HaCaT细胞UCP2蛋白表达的变化及PCF的影响、PCF对UVA损伤HaCaT细胞凋亡蛋白酶激活因子(apoptot-ic protease-activating factor 1,Apaf-1)、细胞色素C(Cyto-chrome C,Cyt C)蛋白表达的影响;电子自旋共振(electronspin resonance,ESR)技术检测ROS的释放量;流式细胞术检测线粒体膜电位;紫外分光光度法测定PCF对UVA损伤HaCaT细胞线粒体呼吸链复合酶Ⅰ(NADH-辅酶Q还原酶)活性的影响。结果正常HaCaT细胞UCP2几乎不表达,UVA照射后表达升高,3 h达高峰,6 h开始逐渐下降;1.42～5.69 mmol.L-1剂量范围内的PCF对UCP2的表达有抑制作用;PCF可明显抑制UVA诱导的ROS产生、线粒体膜电位下降、Cyt C的释放及Apaf-1的表达,可有效抑制UVA损伤后HaCaT细胞呼吸链复合酶I活性的下降。结论 PCF对UVA引起的HaCaT细胞线粒体损伤具有保护作用。     

脓毒症大鼠肾脏功能与其线粒体生物修复机制的实验研究

脓毒症是各种微生物及免疫原性物质引起的全身炎症反应和宿主自身免疫性损伤,其本质是大量炎症因子和炎症介质失控性释放导致的宿主自身免疫性损伤（autoimmunity injury）。脓毒症是当今医学所面临的主要挑战之一,也是儿科疾病的死亡原因之一,进一步发展可引起严重脓毒症（severe sepsis）、脓毒症休克(septic shock)和多器官功能障碍综合征(Multiple Organ Dysfunction Syndrome MODS)甚至死亡。脓毒症的发病机制尚不十分明确,可能的发病机制包括：炎症因子风暴、凝血系统紊乱和微循环、线粒体功能障碍等。线粒体功能障碍在脓毒症,尤其是脓毒症休克患者的病情发展中起了很重要的作用。但在脓毒症恢复过程中,线粒体机制尚不明确。线粒体生物修复（Mitochondrial biogenesis）是维持及恢复线粒体结构与功能的一种细胞程序,在脓毒症恢复中起着重要的作用。在某些因素(尚未明确)的启动下,脓毒症器官线粒体再生修复的相关基因表达增加,可增加线粒体 DNA 的复制与转录,使线粒体相关的功能与结构蛋白表达增加,恢复线粒体的功能。肾脏是机体重要器官,是脓毒症时易损器官。本课题对脓毒症大鼠肾脏的功能状态,肾脏线粒体功能状态、超微形态结构及线粒体生物修复基因表达进行研究,探讨脓毒症肾脏功能损伤与线粒体损伤及修复间的关系,进一步了解脓毒症的病理生理机制。     

线粒体功能障碍与2型糖尿病

2型糖尿病已成为当前威胁人类健康最重要的慢性非传染性疾病之一。大量研究表明,胰岛素抵抗(IR)与β细胞功能下降是其重要发病基础,而这两者均与线粒体功能障碍密切相关。遗传因素、老化现象、活性氧簇(ROS)生成增加、线粒体生物合成下降以及Sirt3基因上调均可能损伤线粒体功能,进而诱发IR;另一方面,解偶联蛋白(UCP)的活性若未处于下述平衡,即既能中和ROS介导的毒性,又不至于将ATP产量降低至影响胰岛素释放的程度,则可破坏β细胞导致其功能下降。因此,以线粒体为靶点的药物或基因治疗将有望成为治疗2型糖尿病的新策略。     

异烟肼致线粒体损伤引起药物性肝损伤研究进展

近年国内外研究表明,线粒体功能异常是各种肝损伤(肝功能衰竭、肝硬化、脂肪肝等)发生的重要机制之一,而在药物性肝损伤发展过程中线粒体也起着重要作用。异烟肼是临床应用广泛、效果显著的抗结核药,但在治疗过程中常引起药物性肝损伤。在某种程度上妨碍了结核病的治疗。研究发现线粒体损伤是异烟肼肝损伤发生发展中关键一环,异烟肼及其毒性产物肼可通过激动氧化应激反应;抑制线粒体呼吸链中酶的活性;干扰细胞能量代谢及对线粒体膜产生攻击等方式使其功能异常,最终导致线粒体损伤,进而启动细胞凋亡程序。本文将对线粒体在异烟肼致药物性肝损伤中的作用进行综述,旨在从亚细胞水平解释异烟肼致肝毒性的机制,为阐明异烟肼的肝毒性提供更为有力的证据。     

线粒体毒性评价及其在创新药物安全性评价中的意义

线粒体是细胞内能量和活性氧自由基(ROS)的主要来源,在病理条件下对细胞的存活与死亡具有十分重要的调控作用。线粒体是药物毒性作用的重要靶标。一些抗病毒药物、抗肿瘤药物和抗生素等可显著诱导肝脏和心脏等靶器官线粒体损伤。药物诱导的线粒体损伤可能涉及多条途径和多种机制。近年来研究表明,线粒体毒性可能是多种已上市药物被迫撤市或受到美国FDA"黑框"警告以及候选药物研发失败的重要原因。因此,在创新药物研发过程中,开展线粒体毒性评价具有十分重要的意义。     

经由线粒体损伤诱发的药源性肝损伤研究进展

线粒体是物质氧化和能量转换的场所,在能量代谢及自由基的产生、衰老、凋亡中起着重要作用。线粒体的呼吸链缺陷、代谢酶失活、结构改变、基因突变等因素都会影响整个细胞的正常功能,从而导致病变的发生。线粒体是药物毒性作用的重要靶标,肝脏作为药物代谢的重要脏器,也是药物引发损伤的主要靶器官。一些抗病毒药物、抗肿瘤药物和抗生素等可显著诱导肝脏线粒体损伤。药物主要通过改变线粒体结构、酶的活性或减少mtDNA的合成,进一步破坏β-脂质氧化和肝细胞的氧化能力,最终诱发肝损伤。综述药源性肝损伤领域有关线粒体损伤的研究进展,为预防和诊断药源性肝损提供思路。     

Mitochondria-targeted peptide antioxidants: Novel neuroprotective agents

Increasing evidence suggests that mitochondrial dysfunction and oxidative stress play a crucial role in the majority of neurodegenerative diseases. Mitochondria are a major source of intracellular reactive oxygen species (ROS) and are particularly vulnerable to oxidative stress. Oxidative damage to mitochondria has been shown to impair mitochondrial function and lead to cell death via apoptosis and necrosis. Because dysfunctional mitochondria will produce more ROS, a feed-forward loop is set up whereby ROS-mediated oxidative damage to mitochondria favors more ROS generation, resulting in a vicious cycle. It is now appreciated that reduction of mitochondrial oxidative stress may prevent or slow down the progression of these neurodegenerative disorders. However, if mitochondria are the major source of intracellular ROS and mitochondria are most vulnerable to oxidative damage, then it would be ideal to deliver the antioxidant therapy to mitochondria. This review will summarize the development of a novel class of mitochondria-targeted antioxidants that can protect mitochondria against oxidative stress and prevent neuronal cell death in animal models of stroke, Parkinson's disease, and amyotrophic lateral sclerosis.     

红景天苷减轻叠氮钠诱导线粒体损伤的作用

目的观察红景天苷对呼吸链复合体IV抑制剂叠氮钠(NaN₃)诱导的线粒体损伤的保护作用，探讨其在防治神经退行性疾病中可能的作用机制。方法将叠氮钠与人神经母细胞瘤细胞株SH-SY5Y共同孵育，MTT法测定细胞存活力，JC-1法检测线粒体膜电位变化。刃天青法检测大鼠脑线粒体功能。结果64 mmol·L^-1叠氮钠与SH-SY5Y共同孵育4 h后，细胞存活率明显下降，线粒体膜电位下降。预先加入红景天苷能明显提高细胞存活率，维持线粒体膜电位。650 μmol·L^-1叠氮钠能使大鼠脑线粒体功能下降，预先加入红景天苷能明显改善线粒体功能。结论红景天苷能够减轻叠氮钠(NaN₃)诱导的线粒体损伤，能够改善线粒体功能，这可能是其抗老年痴呆的机制之一。     

血管内皮细胞线粒体氧化应激与动脉粥样硬化

血管内皮细胞损伤是动脉粥样硬化病理过程的起始环节。线粒体氧化应激与血管内皮细胞功能密切相关,线粒体氧化应激通过诱导线粒体自噬、一氧化氮生成减少、炎症反应、细胞代谢失衡和凋亡,导致血管内皮细胞的功能障碍。同时,血管内皮细胞也通过调控线粒体氧化应激维持自身稳态。本文旨在综述动脉粥样硬化病理过程中线粒体氧化应激诱发血管内皮细胞损伤的主要分子信号通路,为后续研究两者间的分子机制提供参考。     

N-Acetylcysteine Inhibits Patulin-Induced Apoptosis by Affecting ROS-Mediated Oxidative Damage Pathway

Patulin (PAT) belongs to the family of food-borne mycotoxins. Our previous studies revealed that PAT caused cytotoxicity in human embryonic kidney cells (HEK293). In the present research, we systematically explored the detailed mechanism of ROS production and ROS clearance in PAT-induced HEK293 cell apoptosis. Results showed that PAT treatment (2.5, 5, 7.5, 10 μM) for 10 h could regulate the expression of genes and proteins involved in the mitochondrial respiratory chain complex, resulting in dysfunction of mitochondrial oxidative phosphorylation and induction of ROS overproduction. We further investigated the role of N-acetylcysteine (NAC), an ROS scavenger, in promoting the survival of PAT-treated HEK293 cells. NAC improves PAT-induced apoptosis of HEK293 cells by clearing excess ROS, modulating the expression of mitochondrial respiratory chain complex genes and proteins, and maintaining normal mitochondrial function. In addition, NAC protects the activity of antioxidant enzymes, maintains normal GSH content, and relieves oxidative damage. Additionally, 4 mM NAC alleviated 7.5 μM PAT-mediated apoptosis through the caspase pathway in HEK293 cells. In summary, our study demonstrated that ROS is significant in PAT-mediated cytotoxicity, which provides valuable insight into the management of PAT-associated health issues.     

虾青素可能通过H~+传递功能保护NaN_3损伤的人胎肝L-02细胞

观察虾青素(astaxanthin)对呼吸链复合体Ⅳ抑制剂叠氮钠(NaN3)损伤的人胎肝L-02细胞保护作用,并初步探讨其作用机制。100 mmol·L-1 NaN3用于构建肝损伤细胞模型,通过测定不同浓度虾青素(0.01、0.10、1.00及10.00 nmol·L-1)对损伤细胞存活率(MTT检测)、细胞内活性氧(reactive oxygen species,ROS)水平(DCFH-DA检测)、细胞凋亡率(Annexin V-FITC/PI双染法)以及线粒体膜电位(mitochondrial membrane potential,MMP)水平(JC-1法)的影响,发现虾青素能抑制损伤细胞晚期凋亡;对细胞存活率和MMP的保护作用呈现先增加后降低的非剂量依赖性关系,其中0.10 nmol·L-1虾青素表现为较强的保护作用;实验浓度范围内的虾青素并不能显著降低细胞内ROS水平(P>0.05)。为进一步探讨虾青素对损伤细胞的保护作用,人工制备平面双层磷脂膜(planar bilayer lipid membrane,BLM)模拟线粒体膜,测定不同浓度虾青素(0.1%、2.0%、10.0%)对H+的传递能力。结果...     

Mechanisms of hepatotoxicity.

This review addresses recent advances in specific mechanisms of hepatotoxicity. Because of its unique metabolism and relationship to the gastrointestinal tract, the liver is an important target of the toxicity of drugs, xenobiotics, and oxidative stress. In cholestatic disease, endogenously generated bile acids produce hepatocellular apoptosis by stimulating Fas translocation from the cytoplasm to the plasma membrane where self-aggregation occurs to trigger apoptosis. Kupffer cell activation and neutrophil infiltration extend toxic injury. Kupffer cells release reactive oxygen species (ROS), cytokines, and chemokines, which induce neutrophil extravasation and activation. The liver expresses many cytochrome P450 isoforms, including ethanol-induced CYP2E1. CYP2E1 generates ROS, activates many toxicologically important substrates, and may be the central pathway by which ethanol causes oxidative stress. In acetaminophen toxicity, nitric oxide (NO) scavenges superoxide to produce peroxynitrite, which then causes protein nitration and tissue injury. In inducible nitric oxide synthase (iNOS) knockout mice, nitration is prevented, but unscavenged superoxide production then causes toxic lipid peroxidation to occur instead. Microvesicular steatosis, nonalcoholic steatohepatitis (NASH), and cytolytic hepatitis involve mitochondrial dysfunction, including impairment of mitochondrial fatty acid beta-oxidation, inhibition of mitochondrial respiration, and damage to mitochondrial DNA. Induction of the mitochondrial permeability transition (MPT) is another mechanism causing mitochondrial failure, which can lead to necrosis from ATP depletion or caspase-dependent apoptosis if ATP depletion does not occur fully. Because of such diverse mechanisms, hepatotoxicity remains a major reason for drug withdrawal from pharmaceutical development and clinical use.     

T-2 toxin cytotoxicity mediated by directly perturbing mitochondria in human gastric epithelium GES-1 cells

T-2 toxin is one of the most toxic trichothecenes and harmful to human health and animal husbandry. The mechanism underlying its growth suppression remains unclear, especially for mitochondrial damage in human gastric epithelial cells. In the present study, we investigated cell death caused by T-2 toxin in a human gastric epithelial cell line (GES-1) and the possible mechanism of T-2-induced cytotoxicity. T-2 strongly reduced the viability of GES-1 cells in a time- and dose-dependent manner within a small range of concentrations. However, when the concentrations of T-2 were >40 nM, there was no concentration dependence, only time dependence. Moreover, T-2 induced apoptosis, with the activation of caspase-3 in GES-1 and mitochondrial membrane potential (MMP) decrease and cytochrome c release. T-2 also resulted in the accumulation of reactive oxygen species (ROS) and DNA damage with a positive signal of p-H2A.X in GES-1 cells. While T-2 caused a MMP decrease, DNA damage and cell death were not blocked by pretreatment with 3 mM glutathione (GSH), a typical scavenger of ROS. The induction of mitochondrial permeability transition pore (mPTP) regulators voltage-dependent anion channel (VDAC1) and cyclophilin D (CypD) were also observed in T-2-treated cells. Interestingly, cyclosporine A (CsA), a CypD inhibitor, significantly reversed the drop in MMP and the DNA damage, as well as ROS accumulation caused by T-2. Additionally, GES-1 cell death could also be protected to some extent by 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS), an inhibitor of VDAC1, especially the combination of CsA and DIDS, and 3 mM GSH could further enhance the effect of CsA + DIDS on cell viability. In conclusion, our present findings indicate that the T-2 induced MMP decrease, DNA damage and cell death, as well as ROS accumulation in GES-1 cells, starts with T-2 directly perturbing the mitochondria triggering ROS generation by acting on CypD and VDAC1. This study presents a new viewpoint for evaluating the toxicity of T-2 toxin.