Mitochondrial Stress-Initiated Aberrant Activation of the NLRP3 Inflammasome Regulates the Functional Deterioration of Hematopoietic Stem Cell Aging

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Hepatic Mitochondrial Defects in a Nonalcoholic Fatty Liver Disease Mouse Model Are Associated with Increased Degradation of Oxidative Phosphorylation Subunits

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Highlights

• •Stability of oxidative phosphorylation subunits are reduced in a diet-induced mouse model of NAFLD.
• •These changes are associated with impaired activities of electron transport chain complexes and ATP synthesis.
• •Increased mitophagy contributed to enhanced degradation of mitochondrial proteins.

     

EF4影响线粒体氧化磷酸化并调控膀胱癌细胞增殖及迁移

延伸因子4 (EF4)是一种非传统的线粒体延伸因子,参与调控线粒体蛋白质合成过程.在本研究中,我们进一步探索了其在膀胱癌中的作用机制.通过检测EF4在膀胱癌及邻近正常组织中的表达,发现EF4在膀胱癌患者肿瘤组织中异常升高,并在T分期较高的肿瘤中高表达.随后,通过在HTB-9和T-24膀胱癌细胞中敲低EF4的表达,进一步...     

HIGD2A is Required for Assembly of the COX3 Module of Human Mitochondrial Complex IV

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Highlights

• •Quantitative proteomics reveals HIGD2A is required for assembly of the COX3 module.
• •Pulse-SILAC demonstrates that HIGD2A is involved in COX3 biogenesis.
• •Supercomplexes in HIGD2A knockout cells are depleted of COX3.
• •HIGD2A is the first assembly factor identified for the COX3 module of Complex IV.

     

JAK3蛋白在鼻咽癌细胞中参与STAT活化并受EB病毒潜伏膜蛋白1调控

为了探讨在鼻咽癌细胞（NPC）中是否存在EB病毒潜伏膜蛋白1（LMP1）/JAK3/STAT信号传导途径,首先采用RT-PCR方法对NPC JAK家族4种成员检测,发现在两株鼻咽癌细胞株CNE1和HNE2中该家族4种成员均有表达.选择最有可能与LMP1相互作用的JAK家族成员JAK3作为我们的研究对象.利用已建立的一株受四环素衍生物强力霉素(doxycycline,Dox)调控的LMP1表达的鼻咽癌细胞系(Tet-on-LMP1 HNE2),诱导Tet-on-LMP1 HNE2细胞LMP1动态表达,蛋白质印迹发现JAK3的表达方式呈剂量和时间依赖性.采用瞬间转染方法将STAT报告基因质粒（GRR-Luc）转染入pTet-on-LMP1 HNE2细胞中,不同剂量的Dox促使LMP1的表达可以激活STAT报告基因活性,在0.06mg/L Dox诱导36 h时,STAT活性最高.在该条件下,加入3 μmol/L JAK3特异性抑制剂WHI-P131时,可抑制STAT的活性.结果表明：JAK3的表达在NPC细胞中受LMP1的调控,LMP1可以通过调控JAK3的表达参与STAT的活化.在鼻咽癌细胞中存在LMP1/JAK3/STAT信号途径并可能在其发生发展过程中起重要作用.     

TNP-470 Inhibits Oxidative Stress,Nitric Oxide Production and Nuclear Factor Kappa B Activation in a Rat Model of Hepatocellular Carcinoma

The objective of this study is to determine if treatment with the angiogenesis inhibitor TNP-470 results in impairment of oxidative stress, inhibition of nuclear factor kappa B (NF-κB) activation and decrease of nitric oxide production in an experimental model of rat hepatocarcinogenesis. Tumour was induced by diethylnitrosamine and promoted by two-thirds hepatectomy plus acetaminofluorene administration. Experiments were carried out at 28 weeks after initiating the treatment. TNP-470 was administered at 30 mg/kg, three times per week from 20 to 28 weeks. Carcinomatous tissue growing outside dysplastic nodules and a marked expression of placental glutathione S-transferase were detected in rats with induced carcinogenesis. Liver concentrations of thiobarbituric acid reactive substances, reduced glutathione (GSH) and glutathione disulfide (GSSG) were significantly higher than those of controls and there was a significant increase in the GSSG/GSH ratio. Tumour growth was accompanied by augmented expression of inducible nitric oxide synthase, activation of (NF-κB) and proteolysis of IkappaB. All these effects were absent in animals receiving TNP-470. Our results indicate that TNP-470 inhibits oxidative stress, nitric oxide production and NF-κB activation induced by experimental hepatocarcinogenesis. These changes would contribute to the beneficial effects of TNP-470 in cancer treatment.     

SEMA3B基因在鼻咽癌组织中的表达、杂合性丢失和甲基化分析

SEMA3B基因定位于鼻咽癌高频缺失区域3p21.3上,最近被证明具有抑瘤基因的功能.分析了鼻咽癌组织中SEMA3B基因的表达、杂合性丢失(LOH)和甲基化情况.首先应用逆转录-聚合酶链式反应(RT-PCR)方法检测了33例鼻咽癌组织和15例慢性鼻咽炎组织中SEMA3B基因的表达,结果显示75.8%(25/33)鼻咽癌组织中SEMA3B基因表达缺失或下调,显著低于慢性鼻咽炎组织中的表达(P=0.001).进一步选取3个微卫星位点D3S1568、D3S1621和D3S4597分析了20例鼻咽癌组织中SEMA3B基因LOH的情况,结果表明3个位点的丢失率分别为10%、20%和15%,总的丢失率为45%,统计分析发现LOH与基因表达之间存在明显相关(P=0.023).最后,采用甲基化特异性PCR方法分析了SEMA3B基因启动子区甲基化,结果发现在100%的鼻咽癌组织和73.3%的慢性鼻咽炎组织中检测到SEMA3B基因启动子区高甲基化.由此得出结论,SEMA3B基因在鼻咽癌组织中表达缺失或下调,LOH是引起其表达异常的原因之一.     

Malondialdehyde,an Oxidative Stress Marker in Oral Squamous Cell Carcinoma—A Systematic Review and Meta-Analysis

Objective: To qualitative and quantitatively review published literature assessing the oxidative stress marker malondialdehyde (MDA) in oral squamous cell carcinoma (OSCC). Methodology: Pubmed (MeSH), Science Direct, Scopus, Web of Science, Willey Online Library, Cochrane, and Cross Reference were searched for studies assessing MDA levels in OSCC samples. Results: From the 1008 articles identified, 849 were excluded based on title and abstract screening due to duplication and irrelevance to the topic of interest. Full-text assessment of the remaining 159 articles led to the inclusion of only 46 articles that satisfied the selection criteria. Of these, only 26 studies had data compatible for quantitative analysis. The MDA levels in OSCC groups are significantly increased (p < 0.00001) in plasma, serum, and saliva samples in the majority of the studies evaluated. In contrast, MDA levels in OSCC tissue samples are significantly attenuated (p < 0.00001) compared to healthy controls, supported by fewer studies. Conclusions: The augmented MDA levels in plasma, serum, and saliva samples of the OSCC reflect the heightened oxidative stress level accurately. Further studies are required to understand the attenuated MDA levels in the tissue samples of OSCC. Correlation analysis between MDA levels with established clinicopathological prognostic markers could aid in formulating oxidative stress-based prognostication and treatment planning.     

Cyclic Stretch Induces Inflammatory Cytokines via the Oxidative Stress and NF-ΚB Pathways Activation in Human Keratoconic Fibroblasts

The cornea is a load-bearing tissue. Lower biomechanical properties in the local tissue of keratoconic cornea evoke mechanical stress increase. Inflammatory cytokines have been shown to be over-expressed in patients with keratoconus. However, how mechanical stimuli are involved in the production of inflammatory cytokines in keratoconus remains unclear. The objective of the study is to determine the role of mechanical stretch in the regulation of inflammatory cytokines and the underlying mechanisms in keratoconus. Human keratoconic fibroblasts (hKCFs) were subjected to 12% cyclic mechanical stretch at 0.1 Hz or in static conditions as controls. N-acetyl cysteine (NAC) and pyrrolidine dithiocarbamate and pyrrolidine dithiocarbamate (PDTC) were used to inhibit reactive oxygen species (ROS) production and NF-κB pathway respectively. ROS production was measured using 2’,7’-dichlorodihydrofluorescindiacetate probe. Conditioned media and cell lysates were collected for protein assessment. Cyclic stretch-induced a higher production of intercellular cell adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-8 in hKCFs than static controls. ROS was also elevated in response to cyclic stretch. Inhibition of ROS or NF-κB attenuated stretch-induced ICAM-1, TNF-α, IL-6, and IL-8. Inhibition of stretch-induced ROS production by NAC also attenuated NF-κB activation. Our findings suggest that mechanical stretch may induce the release of inflammatory cytokines by activating oxidative stress and NF-kB pathway, and ROS may positively control NF-κB signaling. Over-expression of inflammatory cytokines induced by mechanical stretch may play a role in progression of keratoconus.     

PON3 is upregulated in cancer tissues and protects against mitochondrial superoxide-mediated cell death

To achieve malignancy, cancer cells convert numerous signaling pathways, with evasion from cell death being a characteristic hallmark. The cell death machinery represents an anti-cancer target demanding constant identification of tumor-specific signaling molecules. Control of mitochondrial radical formation, particularly superoxide interconnects cell death signals with appropriate mechanistic execution. Superoxide is potentially damaging, but also triggers mitochondrial cytochrome c release. While paraoxonase (PON) enzymes are known to protect against cardiovascular diseases, recent data revealed that PON2 attenuated mitochondrial radical formation and execution of cell death. Another family member, PON3, is poorly investigated. Using various cell culture systems and knockout mice, here we addressed its potential role in cancer. PON3 is found overexpressed in various human tumors and diminishes mitochondrial superoxide formation. It directly interacts with coenzyme Q10 and presumably acts by sequestering ubisemiquinone, leading to enhanced cell death resistance. Localized to the endoplasmic reticulum (ER) and mitochondria, PON3 abrogates apoptosis in response to DNA damage or intrinsic but not extrinsic stimulation. Moreover, PON3 impaired ER stress-induced apoptotic MAPK signaling and CHOP induction. Therefore, our study reveals the mechanism underlying PON3's anti-oxidative effect and demonstrates a previously unanticipated function in tumor cell development. We suggest PONs represent a novel class of enzymes crucially controlling mitochondrial radical generation and cell death.     

SII、COP-NLR评分与局部晚期鼻咽癌患者临床病理特征和预后的关系研究

摘要 目的：探讨系统性免疫炎症指数（SII）、血小板计数和中性粒细胞与淋巴细胞比值（COP-NLR）评分与局部晚期鼻咽癌患者临床病理特征和预后的关系。方法：选择2015年1月到2017年12月徐州医科大学附属医院收治的94例局部晚期鼻咽癌患者，计算SII和COP-NLR评分，受试者工作特征（ROC）曲线确定治疗前SII的最佳临界值，比较不同SII、COP-NLR评分局部晚期鼻咽癌患者临床病理特征的差异。绘制Kaplan-Meier生存曲线分析不同SII、COP-NLR评分的局部晚期鼻咽癌患者总生存期（OS）的差异，单因素和多因素Cox回归分析影响患者预后的危险因素。结果：根据SII最佳临界值、COP-NLR评分标准将局部晚期鼻咽癌患者分为低SII组（46例）和高SII组（48例），低COP-NLR组（0-1分，45例）和高COP-NLR组（2分，49例）。高SII组、高COP-NLR组TNM分期Ⅳa期、淋巴结转移、颅底侵犯比例高于低SII组、低COP-NLR组（P＜0.05）。高SII组、高COP-NLR组的5年OS明显降低（P＜0.05）。TNM分期Ⅳa期、SII升高、COP-NLR评分升高是局部晚期鼻咽癌患者预后不良的危险因素（P＜0.05）。结论：局部晚期鼻咽癌患者高SII、高COP-NLR评分与恶性病理特征和低生存率有关，SII、COP-NLR评分可作为局部晚期鼻咽癌预后预测的潜在生物学标志物。     

GLP-1 Receptor Signaling in Astrocytes Regulates Fatty Acid Oxidation,Mitochondrial Integrity,and Function

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Dietary Restriction at Old Age Lowers Mitochondrial Oxygen Radical Production and Leak at Complex I and Oxidative DNA Damage in Rat Brain

Previous studies in mammalian models indicate that the rate of mitochondrial reactive oxygen species ROS production and the ensuing modification of mitochondrial DNA (mtDNA) link oxidative stress to aging rate. However, there is scarce information concerning this in relation to caloric restriction (CR) in the brain, an organ of maximum relevance for ageing. Furthermore, it has never been studied if CR started late in life can improve those oxidative stress-related parameters. In this investigation, rats were subjected during 1 year to 40% CR starting at 24 months of age. This protocol of CR significantly decreased the rate of mitochondrial H₂O₂ production (by 24%) and oxidative damage to mtDNA (by 23%) in the brain below the level of both old and young ad libitum-fed animals. In agreement with the progressive character of aging, the rate of H₂O₂ production of brain mitochondria stayed constant with age. Oxidative damage to nuclear DNA increased with age and this increase was fully reversed by CR to the level of the young controls. The decrease in ROS production induced by CR was localized at Complex I and occurred without changes in oxygen consumption. Instead, the efficiency of brain mitochondria to avoid electron leak to oxygen at Complex I was increased by CR. The mechanism involved in that increase in efficiency was related to the degree of electronic reduction of the Complex I generator. The results agree with the idea that CR decreases aging rate in part by lowering the rate of free radical generation of mitochondria in the brain.     

利拉鲁肽对二甲双胍控制不佳的肥胖/超重2型糖尿病患者氧化应激、NLRP3炎症小体及脂肪因子水平的影响

摘要 目的：探讨利拉鲁肽对二甲双胍控制不佳的肥胖/超重2型糖尿病（T2DM）患者氧化应激、NLRP3炎症小体及脂肪因子水平的影响。方法：选择2018年2月-2020年1月期间河北北方学院附属第一医院收治的二甲双胍控制不佳的肥胖/超重T2DM患者160例。按照随机数字表法将患者分为对照组（80例,阿卡波糖治疗）和研究组（80例,阿卡波糖联合利拉鲁肽治疗）。观察两组的收缩压（SBP）、腰臀比（WHR）、体质量指数（BMI）、胰岛素抵抗指标、糖脂代谢指标、氧化应激指标、核苷酸结合寡聚化结构域样受体蛋白3（NLRP3）炎症小体及脂肪因子水平变化情况。结果：两组治疗后BMI、WHR、SBP均下降,且研究组的下降幅度更大（P<0.05）。两组治疗后胰岛?茁细胞分泌功能指数（HOMA-?茁）升高,胰岛素抵抗指数（HOMA-IR）下降,且研究组的改变幅度更大（P<0.05）。两组治疗后甘油三酯（TG）、总胆固醇（TC）、糖化血红蛋白（HbA1c）、低密度脂蛋白胆固醇（LDL-C）、空腹血糖（FPG）下降,高密度脂蛋白胆固醇（HDL-C）升高,且研究组的改变幅度更大（P<0.05）。两组治疗后丙二醛（MDA）下降,谷胱甘肽过氧化物酶（GSH-PX）、超氧化物歧化酶（SOD）升高,且研究组的改变幅度更大（P<0.05）。两组治疗后NLRP3炎症小体均下降,且研究组的改变幅度更大（P<0.05）。两组治疗后脂联素升高,瘦素下降,且研究组的改变幅度更大（P<0.05）。结论：利拉鲁肽应用于治疗二甲双胍控制不佳的肥胖/超重T2DM患者,可减轻氧化应激,有效改善糖脂代谢,调节NLRP3炎症小体及脂肪因子水平。     

LMP1羧基端活化区3对鼻咽癌干细胞SP18迁移与侵袭的影响

为了观察潜伏性膜蛋白1(LMP1)羧基端活性区3(CTAR3)对鼻咽癌干细胞SP18迁移与侵袭的影响,本研究通过建立稳定表达LMP1及CTAR3突变型LMP1(LMP1△252-351)的SP18细胞系(即SP18-LMP1和SP18-LMP1△252-351),观察LMP1-CTAR3缺失突变后对SP18细胞增殖、迁移与侵袭的影响.采用基因芯片分析SP18-LMP1和SP18-LMP1△252-351间的差异表达基因,并验证基因的表达,用生物信息学分析差异表达基因间的相互关系.结果显示:a.SP-LMP1△252-351细胞生长速度较SP-LMP1细胞明显变缓,克隆形成和迁移与侵袭能力降低(n=3,P0.05);b.鉴定出LMP1羧基端CTAR3影响SP18细胞迁移与侵袭的18个基因(其中表达上调基因13个,下调基因5个),经荧光定量PCR验证与基因芯片检测结果基本一致.c.13个差异基因间相互联系,网络节点联系最多的基因是FN1、MMP14、THBS1、ITGA2、IL1B和IL6基因.结果提示,LMP1羧基端CTAR3可能通过调节FN1、MMP14、THBS1、ITGA2、IL1B和IL6基因的表达,发挥其促鼻咽癌干细胞SP18细胞迁移与侵袭的功能.     

The Mitochondrial Acyl-carrier Protein Interaction Network Highlights Important Roles for LYRM Family Members in Complex I and Mitoribosome Assembly

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Highlights

• •The interaction network of NDUFAB1 reveal associations with 9 known LYRM proteins as well as more than 20 other proteins involved in mitochondrial respiratory chain complex and mitochondrial ribosome assembly.
• •The LYRM protein AltMiD51 is required for the stability of assembly factor MALSU1 and optimal assembly of the mitoribosome.
• •LYRM2 is important for integration of the N-module into respiratory chain complex I.

     

Mimosine Mitigates Oxidative Stress in Selenium Deficient Seedlings of Vigna radiata. Part II: Mitochondrial Uptake of 75Selenium and Mimosine

During the growth of selenium (Se)-deficient seedlings of Vigna radiata, exposure to mimosine [2-amino-3-(3-hydroxy-4-oxo-1H-pyridin-1-yl)-propanoic acid], a nonprotein plant amino acid, effectively mitigated stress at 0.1 mM, as reflected in enhancement of growth and efficiency of mitochondrial functions. Since the changes in the seedlings elicited by exposure to mimosine were similar to those effected by Se at an optimal exposure level of 0.75 ppm (Sreekala et al., Biol Trace Elem Res 70:193–207, 1999), the uptake of Se and that of mimosine itself was individually studied in the respiring mitochondria of Se-deficient seedlings (−Se-stressed group) in comparison with those exposed to mimosine during growth at 0.1 mM (Mim 0.1 group). In both groups, the mitochondrial uptake of ⁷⁵Se at 10 μM added increased linearly up to 2 min, attaining steady-state levels thereafter. Uptake levels were 2.3-fold higher in the Mim 0.1 group than in the −Se-stressed group. Double-reciprocal plots of mitochondrial ⁷⁵Se uptake against 2–20 μM in the medium were nonlinear and negative cooperative effects during the uptake were confirmed by Scatchard plots, whereas Hill coefficients were 0.8 and 0.85 for the two groups. Mitochondrial uptake of mimosine, at added levels of 25 or 50 μM, increased linearly up to 1 min and decelerated thereafter. Initial uptake levels of mimosine at 1 min were higher by 6.5-fold at 25 μM and 4-fold at 50 μM in the Mim 0.1 group than those in the −Se-stressed group. Initial uptake levels with added mimosine up to 50 or 100 μM yielded nonlinear double-reciprocal plots; and kinetic analyses at 5 to 50 μM revealed the prevalence of positive cooperativity in the −Se-stressed group and negative cooperativity in the Mim 0.1 group. Involvement of active thiol groups in the uptake of both Se and mimosine were indicated by inhibition studies. Evidence presented for mimosine mediated increase in mitochondrial Se uptake and cooperative interactions thereof underscores the metabolic significance of mimosine.