Serum manganese superoxide dismutase and thioredoxin are potential prognostic markers for hepatitis C virus-related hepatocellular carcinoma

AIM:To evaluate the clinical significance of oxidative stress markers in patients with hepatitis C virus(HCV)related hepatocellular carcinoma(HCC).METHODS:Sixty-four consecutive patients who were admitted to Kagoshima University Medical and Dental Hospital were enrolled in this retrospective study.All patients had chronic liver disease(CLD) due to infection with HCV.Thirty patients with HCV-related HCC,34 with HCV-related CLD without HCC(non-HCC),and 20 healthy volunteers(HVs) were enrolled.Possible associations between serum manganese superoxide dismutase(MnSOD) and thioredoxin(TRX) levels and clinical parameters or patient prognosis were analyzed over a mean follow-up period of 31.7 mo.RESULTS:The serum MnSOD levels were significantly higher in patients with HCV-related HCC than in patients without HCC(P = 0.03) or HVs(P < 0.001).Similarly,serum TRX levels were also significantly higher in patients with HCV-related HCC than in patients without HCC(P = 0.04) or HVs(P < 0.01).However,serum levels of MnSOD and TRX were not correlated in patients with HCC.Among patients with HCC,the overall survival rate(OSR) was lower in patients with MnSOD levels ≥ 110 ng/mL than in patients with levels < 110 ng/mL(P = 0.01),and the OSR tended to be lower in patients with TRX levels < 80 ng/mL(P = 0.05).In addition,patient prognosis with HCC was poorest with serum MnSOD levels ≥ 110 ng/mL and serum TRX levels < 80 ng/mL.Furthermore,a multivariate analysis using a Cox proportional hazard model and serum levels of five factors(MnSOD,prothrombin time,serum albumin,serum α-fetoprotein(AFP),and serum des-γ-carboxy prothrombin) revealed that MnSOD levels ≥ 110 ng/mL(risk ratio:4.12,95% confidential interval:1.22-13.88,P = 0.02) and AFP levels ≥ 40 ng/mL(risk ratio:6.75;95% confidential interval:1.70-26.85,P < 0.01) were independent risk factors associated with a poor patient prognosis.CONCLUSION:Serum MnSOD and TRX levels are potential clinical biomarkers that predict patient prognosis in HCV-related HCC.

Characterization of a thermostable manganese-containing superoxide dismutase from inshore hot spring thermophile Thermus sp.JM1

A thermostable superoxide dismutase （SOD） from the inshore thermophile Thermus sp. JM1 was purified to homogeneity by steps of fractional ammonium sulfate precipitation, DEAE-Sepharose chromatography and Phenyl-Sepharose chromatography. The specific activity of the purified native enzyme was 1 656 U/mg. A sod gene from this strain was cloned and overexpressed in Escherichia coli （E. coli）. The prepared apo-enzyme of the purified recombinant SOD （rSOD） was reconstituted with either Fe or Mn by means of incubation with appropriate metal salts. As a result, only Mn 2＋ - reconstituted rSOD （Mn-rSOD） exhibited the specific activity of 1 598 U/mg. SOD from Thermus sp. JM1 was Mn-SOD, judging by the specific activities analysis of Fe or Mn reconstituted rSODs and the insensitivity of the native SOD to both cyanide and H 2 O 2 . Both the native SOD and Mn- rSOD were determined to be homotetramers with monomeric molecular mass of 26 kDa and 27.5 kDa, respectively. They had high thermostability at 50 ° C and 60 ° C, and showed striking stability across a wide pH span from 4.0 to 11.0.

INFLUENCE OF ZINC，MANGANESE AND SELENIUM ONSUPEROXIDE DISMUTASE ACTIVITY IN LUNGCANCER TISSUE AND CELL IN CULTURE

In this experiment,the cancer tissues and cells,Which were derived from Lewis lung cancer and A549 lung Cancer cell line,were respectively divided into four groups and zinc, manganese and selenium were respectively added to the medium for 24 hours. The superoxide dismutase activity in the tissues and the cells was estimated. It was found that the SOD activity was enhanced by zinc and manganese and the effect of zinc on SOD activity was superior to that of manganese. We supposed that the enhance of the SOD activity was relative to the activation of the SOD apoenzymes. This experimental result indicated that the inhibitory effect of zinc and manganese on carcinogenesis was achieved by SOD and the elements might be considered a SOD activator.

Transcript profiles of mitochondrial and cytoplasmic manganese superoxide dismutases in Exopalaemon carinicauda under ammonia stress

Superoxide dismutase(SOD) is one of the most important antioxidant defense enzymes,and is considered as the first line against oxidative stress. In this study,we cloned a mitochondrial manganese(Mn) SOD( m Mn SOD) c DNA from the ridgetail white prawn E xopalaemon carinicauda by using rapid amplification of c DNA ends(RACE) methods. The full-length c DNA for m Mn SOD was 1 014-bp long,containing a 5′-untranslated region(UTR) of 37-bp,a 3′-UTR of 321-bp with a poly(A) tail,and included a 657-bp open reading frame encoding a protein of 218 amino acids with a 16-amino-acid signal peptide. The protein had a calculated molecular weight of 23.87 k Da and a theoretical isoelectric point of 6.75. The m Mn SOD sequence included two putative N-glycosylation sites(NHT and NLS),the Mn SOD signature sequence 1 80 DVWEHAYY 187,and four putative Mn binding sites(H48,H96,D180,and H184). Sequence comparison showed that the m Mn SOD deduced amino acid sequence of E. carinicauda shared 97%,95%,89%,84%,82%,72%,and 69% identity with that of M acrobrachium rosenbergii,M acrobrachium nipponense,Fenneropeneaus chinensis,Callinectes sapidus,P erisesarma b idens,D anio r erio,and Homo sapiens,resectively. Quantitative real-time RT-PCR analysis showed that m Mn SOD transcripts were present in all E. carinicauda tissues examined,with the highest levels in the hepatopancreas. During an ammonia stress treatment,the transcript levels of m Mn SOD and c Mn SOD were up-regulated at 12 h in hemocytes and at 24 h in the hepatopancreas. As the duration of the ammonia stress treatment extended to 72 h,the transcript levels of m Mn SOD and c Mn SOD significantly decreased both in hemocytes and hepatopancreas. These findings indicate that the SOD system is induced to respond to acute ammonia stress,and may be involved in environmental stress responses in E. carinicauda.

Differential Regulation of Proteins and a Possible Role for Manganese Superoxide Dismutase in Bioluminescence of Panellus stipticus Revealed by Suppression Subtractive Hybridization

Suppression subtractive hybridization (SSH) was employed to investigate bioluminescence in Panellus stipticus (Bull.) P. Karst. by detecting proteins differentially expressed in bioluminescent and luminescent strains. Comparisons of luminescent and non-luminescent monokaryon cultures of North American strains revealed differences in transcript levels of proteins responsible for post-translational modification (PTM) of enzymes. A similar comparison of a luminescent strain of P. stipticus from North America with a non-luminescent European strain revealed the presence of extracellular manganese superoxide dismutase (MnSOD) in the luminescent form, in addition to proteins involved in PTM. The application of MnSOD-specific inhibitors to luminescent mycelium resulted in the rapid loss of luminescence. The relevance to luminescence of proteins involved in PTM is discussed, together with a possible role for MnSOD that considers the potential for SODs to form stable complexes with catechols revealed in previously published research. In light of the recent discovery that hispidine may be the precursor of fungal luciferin, we consider a hypothetical mechanism for fungal luminescence in which the ο-hydroquinone moiety of a hispidine derivative ligates with the extracellular form of MnSOD producing a semiquinone-radical complex, with the resultant semiquinonato complex potentially reacting with molecular oxygen or other reactive oxygen species to produce sufficiently excited intermediates to emit light on relaxation.

阿尔茨海默病患者血清Aβ42、胆红素及MnSOD与认知损害的相关性

目的探讨阿尔茨海默病(alzheimer’s disease,AD)患者β淀粉样蛋白42(amyloidβ-protein,Aβ)、胆红素、锰超氧化物歧化酶(Mn-superoxide dismutase,MnSOD)水平变化及与患者认知损害的相关性。方法选取2020年8月至2022年8月于河南大学第一附属医院接受治疗的106例AD患者作为观察组,另入选与观察组年龄、性别相匹配的110名老年健康体检者作为对照组。分析所有研究对象的一般资料,采用蒙特利尔认知评估量表(montreal cognitive assessment,MoCA)对观察组患者认知功能进行评估,通过酶联免疫吸附法(enzyme-linked immunoSorbent assay,ELISA)测定血清Aβ42、胆红素及MnSOD水平,同时对比不同脑电(electroencephalogram,EEG)监测结果下血清Aβ42、胆红素及MnSOD的差异,分析AD患者血清指标与EEG异常、MoCA评分之间的关系。结果与对照组相比,观察组血清Aβ42、胆红素、Mn-SOD均显著低,差异具有统计学意义(P<0.05);经单因素分析结果显示,MoCA评分在Aβ42≤2.33 mg/L、胆红素≤20μmol/L、MnSOD≤104.20 NU/mL、EEG重度异常上差异具有统计学意义(P<0.05),多元线性回归分析结果显示Aβ42≤2.33 mg/L、胆红素≤20μmol/L、Mn-SOD≤104.20 NU/mL、EEG重度异常是影响AD患者发生认知损害的危险因素(P<0.05);不同EEG严重程度,其血清Aβ42、胆红素及Mn-SOD相比具有统计学意义(P<0.05);相关性分析结果显示,血清Aβ42、胆红素及MnSOD与MoCA评分、EEG异常程度均具有密切关系(P<0.05)。结论AD患者血清Aβ42、胆红素及MnSOD水平均显著低于正常老年群体,与患者认知损害具有明显相关性,且与患者EEG异常程度密切相关,临床可将血清Aβ42、胆红素及MnSOD水平作为早期预测认知功能障碍的重要指标,以便尽早给予AD患者采取针对性处治措施。

MnSOD、NfL、Lp-PLA2与卒中后认知障碍相关性及联合检测意义

目的探讨锰超氧化物歧化酶(MnSOD)、神经丝轻链蛋白(NfL)、脂蛋白相关磷脂酶A2(Lp-PLA2)与卒中后认知障碍(PSCI)相关性及联合检测意义,以期为临床早期预测评估、制定干预方案提供参考。方法选取2020年6月―2023年1月郑州市中心医院收治的100例脑卒中患者,根据是否发生PSCI分为PSCI组、无PSCI组,比较两组基线资料、入院时、2周后、4周后MnSOD、NfL、Lp-PLA2,Pearson分析MnSOD、NfL、Lp-PLA2与MoCA评分相关性,多元线性回归分析PSCI的相关影响因素,采用受试者工作特征曲线(ROC)评估入院时、2周后MnSOD、NfL、Lp-PLA2预测PSCI的价值。结果PSCI组入院时NIHSS评分、脑白质疏松和脑萎缩患者占比高于无PSCI组,MoCA评分低于无PSCI组(P<0.05);两组2周后、4周后MnSOD均高于入院时,NfL、Lp-PLA2均低于入院时,PSCI组2周后、4周后MnSOD低于无PSCI组,NfL、Lp-PLA2高于无PSCI组(P<0.05);入院时、2周后、4周后MnSOD与MoCA评分呈正相关,NfL、Lp-PLA2与MoCA评分呈负相关(P<0.05);入院时NIHSS评分、脑白质疏松、脑萎缩、MnSOD、NfL、Lp-PLA2均与MoCA评分显著相关(P<0.05);入院时、2周后两两联合的AUC大于单独指标,三者联合的AUC>两两联合的AUC,且2周后三者联合的AUC 0.944>入院时三者联合的AUC 0.932,预测敏感度为84.62%,特异度为93.44%。结论MnSOD、NfL、Lp-PLA2为脑卒中后PSCI的重要因素,能为临床早期评估预测PSCI提供参考依据,以针对性展开后续治疗,改善预后。

基于SIRT3/MnSOD信号通路探讨健脾调脂方对心力衰竭大鼠心肌纤维化的影响

目的 基于沉默调节蛋白3/锰超氧化物歧化酶(SIRT3/MnSOD)信号通路探讨健脾调脂方改善心力衰竭心肌纤维化的机制。方法 从70只雄性SD大鼠中随机选择10只作为正常组,其余60只采用阿霉素尾静脉注射方法建立心力衰竭心肌纤维化模型。造模成功后,将存活大鼠随机分为模型组、卡托普利组、健脾调脂方低剂量组、健脾调脂方中剂量组、健脾调脂方高剂量组,每组10只。卡托普利组给予卡托普利2.6 mg/kg灌胃,健脾调脂方低、中、高剂量组分别给予健脾调脂方4.38 g/kg、8.75 g/kg、17.75 g/kg灌胃,正常组和模型组给予等体积生理盐水灌胃,均1次/d,连续6周。末次灌胃40 min后,采用心脏彩超评估心功能;取左心室心肌组织,HE及Masson染色观察病理形态及心肌纤维化情况,计算心肌胶原容积分数;Western blot法检测心肌组织中Ⅰ型胶原蛋白(CollagenⅠ)、Ⅲ型胶原蛋白(CollagenⅢ)、SIRT3及MnSOD蛋白表达情况,RT-qPCR法检测心肌组织中CollagenⅠ、CollagenⅢ、SIRT3及MnSOD mRNA表达情况。结果 模型组大鼠左心室舒张末期内径(LVIDd)、左心室收缩末期内径(LVIDs)及心肌胶原容积分数均高于正常组(P均<0.05),左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)均明显低于正常组(P均<0.05),心肌纤维断裂、出血;卡托普利组和健脾调脂方各组LVIDd、LVIDs及心肌胶原容积分数均明显低于模型组(P均<0.05),LVEF、LVFS均明显高于模型组(P均<0.05),心肌纤维化减轻,其中卡托普利组和健脾调脂方中、高剂量组减轻更明显,但仍见少量出血。模型组大鼠心肌组织中CollagenⅠ、CollagenⅢ蛋白及mRNA相对表达量均明显高于正常组(P均<0.05),SIRT3、MnSOD蛋白及mRNA相对表达量均明显低于正常组(P均<0.05);卡托普利组和健脾调脂方中、高剂量组大鼠心肌组织中CollagenⅠ、CollagenⅢ蛋白及mRNA相对表达量均明显低于模型组(P均<0.05),卡托普利组和健脾调脂方高剂量组SIRT3、MnSOD蛋白及mRNA相对表达量均明显高于模型组(P均<0.05)。结论 健脾调脂方可能通过激活SIRT3/MnSOD信号通路减轻氧化应激,改善心力衰竭大鼠心肌纤维化。

Mitochondrial DNA4977-bp deletion correlated with reactive oxygen species production and manganese superoxide dismutase expression in gastric tumor cells

Background Mitochondrial DNA 4977-bp deletion （△mtDNA^4977） was reported in many human neoplasia. However, its biological significance remains to be evaluated and the molecular mechanism needs to be investigated. In this study, we analyzed the frequency of △mtDNA^4977 in gastric cancer （GC） cell lines and tissues, as well as reactive oxygen species （ROS） contents and manganese superoxide dismutase （MnSOD） expression levels in GC cell lines to explore its biological significance and molecular mechanism. Methods Semi-quantitative PCR and real-time PCR were used to detect the incidence of △mtDNA^4977 in 13 GC cell lines and 272 human gastric tissues （108 GC specimens and the respective adjacent normal tissues, and 56 normal gastric mucosa from non-cancer patients）. We further identified intracellular ROS production by flow cytometry and MnSOD expression by semi-quantitative reverse transcription-PCR （RT-PCR） and Western blotting. Statistical analyses were carried out using the Logistic regression analysis and Kaplan-Meier method. Results Based on our earlier study, we optimized the PCR amplification condition by reducing the cycle number. In this study, we systematically documented the high incidence of △mtDNA^4977 in GC cell lines （10/13, 76.9%）, GC tissues （86/108, 79.6%）, matched normal tissues （73/108, 67.6%）, and normal gastric mucosa of non-cancer patients （29/56, 51.8%）. A significantly higher incidence of mutated △mtDNA^4977 was observed in GC tissues with respect to the adjacent normal tissues （79.6% vs 67.6%, P=-0.045）, and they were both higher than that in normal controls （P 〈0.05）. Most importantly, we linked the △mtDNA^4977 mutations with the expression level of MnSOD and ROS contents. The cell lines containing lower expression level of MnSOD was found to have generally higher frequent △mtDNA^4977 and more ROS. Conclusion The decreased anti-oxidative ability, which leads to increased ROS contents, is correlated with the mtDNA damage during gastric carcinogenesis.

The Expression of Manganese Superoxide Dismutase Gene from Nelumbo nucifera Responds Strongly to Chilling and Oxidative Stresses

A manganese superoxide dismutase （Mn-SOD） gene, NnMSD1, was identified from embryonic axes of the sacred lotus （Nelumbo nucifera Gaertn.）. The NnMSD1 protein contains all conserved residues of the Mn-SOD protein family, including four consensus metal binding domains and a signal peptide for mitochondrial targeting. Southern blot analysis suggests the existence of two Mn.SOD genes in sacred lotus. NnMSD1 was highly expressed in developing embryonic axes during seed development, but appeared in cotyledons only at the early stage of development and became undetectable in the cotyledons during late embryogenesis. The expression of the NnMSD1 gene in germinating embryonic axes, in response to various stresses such as heat shock, chilling, and exposure to stress-related chemicals, was also studied. Heat shock strongly inhibited the expression of the NnMSD1 gene, whereas the NnMSD1 transcript level increased strongly in chilling stress treatment. An increase in expression was also highly induced by H2O2 in germinating embryonic axes. The results suggest that the expression pattern of the NnMSD1 gene differed between developing axes and cotyledons, and that the NnMSD1 gene expression responds strongly to chilling and oxidative stress.

Effect of alcohol exposure on hepatic superoxide generation and hepcidin expression

AIM: To understand the role of mitochondrial-produced superoxide(O 2 ?) in the regulation of iron-regulatory hormone, hepcidin by alcohol in the liver. METHODS: For alcohol experiments, manganese superoxide dismutase knockout mice heterozygous for Sod2 gene expression(Sod2 +/) and age-matched littermate control mice(LMC), expressing Sod2 gene on both alleles, were exposed to either 10%(w/v) ethanol in the drinking water or plain water(control) for 7 d. Total cellular O 2 ? levels in hepatocytes isolated from the livers of mice were measured by electron paramagnetic resonance spectroscopy. The mitochondrial-targeted, O 2 ?-sensitive fluorogenic probe, MitoSOX Red and flow cytometry were utilized to measure O 2 ? in mitochondria. Gene and protein expression were determined by Taqman Real-time quantitative PCR and Western blotting, respectively. RESULTS: Sod2 +/- mice expressed 40% less MnSOD protein(SOD2) in hepatocytes compared to LMC mice. The deletion of Sod2 allele did not alter the basal expression level of hepcidin in the liver. 10% ethanol exposure for 1 wk inhibited hepatic hepcidin mRNA expression three-fold both in Sod2 +/ and LMC mice. O 2 ? levels in hepatocytes of untreated Sod2 +/ mice were three-fold higher than in untreated LMC mice, as observed by electron paramagnetic resonance spectroscopy. O 2 ? levels in mitochondria of Sod2 +/ mice were four-fold higher than in mitochondria of untreated LMC mice, as measured by MitoSOX Red fluorescence and flow cytometry. Alcohol induced a two-fold higher increase in O 2 ? levels in hepatocytes of LMC mice than in Sod2 +/ mice compared to respective untreated counterparts. In contrast, 1 wk alcohol exposure did not alter mitochondrial O 2 ? levels in both Sod2 +/- and control mice. CONCLUSION: Mitochondrial O2 ? is not involved in the inhibition of liver hepcidin transcription and thereby regulation of iron metabolism by alcohol. These findings also suggest that short-term alcohol consumption significantly elevates O 2 ? levels in hepatocytes, which appears not to originate from mitochondria.

Up-regulated manganese superoxide dismutase expression increases apoptosis resistance in human esophageal squamous cell carcinomas

Background Esophageal cancer is one of the most common malignancies in the world. In order to identify the proteins associated with esophageal squamous cell carcinomas （ESCC）, we analyzed the protein profiles of ESCC cases with tumor and matched adjacent normal tissues. Methods Two-dimensional electrophoresis （2-DE） was carried out to analyze the protein profiles. Dysregulated protein spots were identified by Matrix-Assisted Laser Desorption Ionization Time-of-Flight （MALDI-TOF） and verified by liquid chromatography/electrospray ionization ion trap-mass spectrometry/mass spectrometry （LC-ESI-IT MS）. RT-PCR and immunohistochemistry on tissue microarray were performed to confirm the gene dysregulation in esophageal cancerous tissues. RNA interference （RNAi） was used to knock down the gene expression in ESCC cell lines. Apoptosis assay with annexin V-FITC/PI staining was conducted and cells were analyzed by flow cytometry. Results 2-DE showed that two protein spots with approximate molecular weights and different pl were elevated in 12 out of 18 ESCCs as compared to the corresponding normal tissues. Both the two spots were identified as MnSOD by MALDI-TOF and were verified by LC-ESI-IT MS. MnSOD overexpression was detected in 14 tumors out of 24 cases by RT-PCR and 52 tumors out of 116 cases by immunohistochemistry comparing to normal epithelia, siRNA-mediated silencing of MnSOD in KYSE450 and KYSE150 cell lines revealed that MnSOD protected ESCC cells from apoptosis induced by ultraviolet （UV） and doxorubicin （DOX）. Conclusions These findings suggest that there existed two isoforms of MnSOD protein in normal and tumor esophageal tissues. MnSOD was overexpressed in ESCC and its up-regulation in esophageal cancer cells was associated with apoptosis resistance.

AECOPD患者血清MnSOD、CuZnSOD变化及其与疾病转归的关系

目的分析慢性阻塞性肺疾病急性加重期(AECOPD)患者血清锰超氧化物歧化酶(MnSOD)、铜锌超氧化物歧化酶(CuZnSOD)变化及其与疾病转归的关系。方法将2018年11月至2021年12月该院收治的120例AECOPD患者作为AECOPD组,同期75例慢性阻塞性肺疾病稳定期患者作为稳定期组,另选取在该院体检的健康者60例作为对照组。所有AECOPD患者出院后随访1年,AECOPD组根据疾病转归情况分为好转组(n=84),恶化组(n=36)。所有纳入对象入院后均检测血清MnSOD、CuZnSOD水平,比较各组血清MnSOD、CuZnSOD水平变化。采用受试者工作特性曲线(ROC)评估血清MnSOD、CuZnSOD对AECOPD患者疾病转归的预测价值。结果AECOPD组血清MnSOD水平明显低于稳定期组、对照组,血清CuZnSOD水平明显高于稳定期组、对照组,差异有统计学意义(P<0.05)。恶化组血清MnSOD水平明显低于好转组,血清CuZnSOD水平明显高于好转组,差异有统计学意义(P<0.05)。ROC曲线分析显示,血清MnSOD预测AECOPD患者疾病转归的曲线下面积(AUC)为0.874,截断值5.58 U/mL,灵敏度、特异度分别为80.56%、78.57%,血清CuZnSOD预测AECOPD患者疾病转归的AUC为0.845,截断值66.62 U/mL,灵敏度、特异度分别为83.33%、70.32%。结论AECOPD患者血清MnSOD水平降低,CuZnSOD水平升高,二者与患者疾病转归密切相关,在诊断AECOPD患者疾病转归中具有良好的效能。

锰超氧化物歧化酶的催化原理与酶活性调节机制

锰超氧化物歧化酶(MnSOD)催化两分子超氧自由基歧化为分子氧和过氧化氢。超氧自由基被Mn~(3+)SOD氧化成分子氧的反应以扩散的方式进行。超氧自由基被Mn~(2+)SOD还原为过氧化氢的反应以快循环和慢循环两条途径平行进行。在慢循环途径中,Mn~(2+)SOD与超氧自由基形成产物抑制复合物,然后该复合物被质子化而缓慢释放出过氧化氢。在快循环途径中,超氧自由基直接被Mn~(2+)SOD转化为产物过氧化氢,快速循环有利于酶的复活与周转。本文提出温度是调节锰超氧化物歧化酶进入慢速或者快速循环催化途径的关键因素。随着在生理温度范围内的温度升高,慢速循环成为整个催化反应的主流,因而生理范围内的温度升高反而抑制该酶的活性。锰超氧化物歧化酶的双相酶促动力学特性可以用该酶保守活性中心的温度依赖性配位模型进行合理化解释。当温度降低时,1个水分子(或者OH~-)接近Mn、甚至与Mn形成配位键,从而干扰超氧自由基与Mn形成配位键而避免形成产物抑制。因此在低温下该酶促反应主要在快循环通路中进行。最后阐述了几种化学修饰模式对该酶的调节,说明锰超氧化物歧化酶受到多种形式的快速调节(变构调节与化学修饰)。这些快速调节直接改变酶的活化状态,进而调节细胞中超氧自由基和过氧化氢的平衡与流量,为揭示锰超氧化物歧化酶和超氧自由基的生理作用提供新理论。

MnSOD 9Ala/Val基因多态性与冠心病的关系

目的探讨锰超氧化物歧化酶9 Ala/Val(MnSOD9 Ala/Val)基因多态性与冠心病、总超氧化物歧化酶(T-SOD)和锰超氧化物歧化酶(MnSOD)活性以及丙二醛(MDA)浓度的关系。方法采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测262例冠心病患者和100例对照组的MnSOD9 Ala/Val基因多态性的基因型,采用比色法测定血浆T-SOD、MnSOD活性以及MDA浓度。结果与对照组比较,冠心病患者的血浆T-SOD和MnSOD活性[(23.61±16.51)U/ml与(44.01±22.68)U/ml,P<0.001和(21.56±13.11)U/ml与(28.79±8.65)U/ml,P<0.001]明显降低,MDA浓度显著增高[(2.47±0.73),(2.15±0.55)nmol/ml,P<0.01];冠心病患者的MnSOD 9 AA基因型和A等位基因频率较对照组明显增多(64.2%与43.0%,P=0.001和80.0%与67.0%,P=0.014);MnSODAA基因型的MnSOD活牲较VV基因型明显降低[(22.87±13.47)与(32.04±9.19)U/ml,P<0.01)];MnSOD与MDA负相关(r=-0.15,P<0.01)。结论冠心病患者的血浆T-SOD和MnSOD活性明显降低,MDA浓度显著增高;MnSOD 9 Ala/Val基因多态性AA基因型的血浆MnSOD活性降低。

非小细胞肺癌组织中MnSOD、SIRT3的表达及意义

目的探讨非小细胞肺癌(non-small cell lung cancer,NSCLC)组织中锰超氧化物歧化酶(manganese superoxide dismutase,Mn SOD)、去乙酰化酶3(sirtuin 3,SIRT3)的表达,以及两者与NSCLC生物学特征的关系。方法采用免疫组化及Western blot法检测89例NSCLC及对应癌旁(直径≥10 cm)肺组织中Mn SOD、SIRT3蛋白的表达,探讨与NSCLC组织类型、TNM分期、分化程度、淋巴结转移的相关性。结果免疫组化及Western blot结果显示:与癌旁肺组织相比,Mn SOD、SIRT3蛋白在NSCLC中的表达明显降低;免疫组化图像分析结果显示癌旁组织中Mn SOD、SIRT3蛋白含量平均光密度值(OD值)为(0.428±0.031)、(0.403±0.035),而NSCLC组织中Mn SOD、SIRT3蛋白OD值显著降低,且两者表达与NSCLC分化程度、肿瘤T分期呈正相关(P<0.05,P<0.01);而与病理类型及有无淋巴结转移无相关性(P>0.05)。结论 NSCLC组织中MnSOD、SIRT3蛋白表达降低,两者联合检查可能对预测肿瘤的恶性程度有一定的意义。

MnSOD表达特性与食管癌细胞放射敏感性的关系

目的:研究锰超氧化物歧化酶(manganese superoxide dismutase,MnSOD)在一氧化氮(mtric oxide,NO)作用下对食管癌TE-1细胞放射敏感性的影响。方法:采用慢病毒转染法将MnSOD重组质粒转染食管癌TE-1细胞,分别建立中、高水平过量表达MnSOD的稳定转染细胞(TE-1Mm、TE-1Mh)及空载体细胞(TE-1Mn)。进一步采用RT-PCR、Western blot检测转染后TE-1细胞、空载体TE-1Mn细胞、稳定转染细胞TE-1Mm及TE-1Mh中MnSOD mRNA和蛋白的表达;四甲基偶氮唑蓝(MTT)比色实验评价NO供体硝普钠(sodium nitroprusside,SNP)、放射线及二者联合对以上4组细胞的抑制;流式细胞术(FCM)及Western blot检测各组细胞凋亡、活性氧(reactive oxygen species,ROS)荧光强度及蛋白表达的变化。结果:成功建立了稳定中、高水平过量表达MnSOD的TE-1细胞株TE-1Mm和TE-1Mh;RT-PCR及Western blot证实上述2种细胞中含有不同表达水平的MnSOD。MTT法及FCM显示,TE-1Mm细胞的存活率下降,细胞凋亡率上调,而TE-1Mh细胞的存活率上调,细胞凋亡率下降,相应组间相比差异具有统计学意义(P<0.05)。0.5～2mmol/L SNP及2、4、6Gy放射线处理48 h,TE-1Mm细胞生长抑制率明显增加,细胞生长明显减慢,放射增敏比增加,细胞凋亡率上调;TE-1Mh细胞抑制率反而降低,细胞生长加速,放射增敏比降低,细胞凋亡率下降,相应组间相比差异均具有统计学意义(P<0.05)。Western blot结果及FCM显示:0.5～2 mmol/L SNP及2、4、6 Gy放射线处理48 h,与TE-1Mm细胞相比,TE-1Mh细胞MnSOD蛋白表达量及细胞内ROS相对降低,相应组间相比差异均具有统计学意义(P<0.05)。结论:中等水平过量表达MnSOD增加食管癌细胞放射敏感性,抑制增殖,诱导凋亡,而高水平过量表达MnSOD则与之相反,为今后通过MnSOD提高放射敏感性来抑制食管癌或通过其抗拒放射来保护正常细胞提供了可能性。

EGCG对H_2O_2诱导的螺旋神经节细胞MnSOD基因表达的影响

目的 :探讨表没食子儿茶素没食子酸盐 (EGCG)在双氧水 (H2 O2 )诱导耳蜗螺旋神经节细胞 (SGCs)氧化损伤中对线粒体抗氧化酶基因 MnSOD基因表达的影响。方法 :培养离体SGCs,采用半定量RT PCR方法检测加入不同浓度H2 O2 和 /或EGCG后螺旋神经元MnSOD基因的表达情况。以经典抗氧化剂维生素C作对照。结果 :随着H2 O2 浓度提高 ,MnSOD基因的表达亦随之升高 ;在H2 O2 浓度大于 10 0 μmol/L时MnSOD基因表达明显上调 (P <0 .0 5 ) ,10 0 μg/mlEGCG能明显抑制H2 O2 诱导的MnSOD基因表达 (P <0 .0 5 )。结论 :EGCG可能通过清除氧自由基 ,提高MnSOD酶活性 ,抑制H2 O2

西伯利亚蓼PsMnSOD基因的耐盐碱性鉴定及其在盐碱胁迫下的表达模式

植物的超氧化物歧化酶的活性与其在盐胁迫下的防御能力密切相关。本文分析了西伯利亚蓼PsMn-SOD基因在酵母中的表达对酵母耐盐碱性的影响以及西伯利亚蓼中PsMnSOD基因在盐碱胁迫下的表达模式。研究结果表明,PsMnSOD基因在酵母中的表达提高了酵母在盐碱胁迫下的SOD酶活性,并提高了酵母对盐碱胁迫的抗性。RT-PCR结果显示,3%NaHCO3胁迫条件下PsMnSOD基因在西伯利亚蓼的叶、茎和地下茎中均有表达,西伯利亚蓼PsMnSOD基因在茎和地下茎中的表达水平高于在叶中的表达水平,叶中PsMnSOD基因的表达水平随着NaHCO3浓度的增加而上升。本试验表明西伯利亚蓼PsMnSOD基因在抵御盐碱胁迫中起到非常重要的作用。

MnSOD、SIRT3在肺腺癌组织及癌旁组织中的表达及其与临床病理、预后的关系分析

目的分析锰超氧化物歧化酶(MnSOD)、去乙酰化酶3(SIRT3)在肺腺癌组织及癌旁组织中的表达及其与临床病理、预后的关系。方法选取该院心胸血管外科2016年1月至2018年12月收治的60例肺腺癌患者,均留存有肺腺癌及癌旁组织标本。采用免疫组织化学(SP法)检测肺腺癌组织及癌旁组织MnSOD、SIRT3表达,比较其在不同病理特征患者肺腺癌组织MnSOD、SIRT3表达差异,对所有患者予以持续随访,采用Cox回归模型分析影响患者预后的独立危险因素,并绘制Kaplan-Meier生存曲线,分析MnSOD、SIRT3对肺腺癌患者生存时间的影响。结果肺腺癌组织中MnSOD阳性表达率、SIRT3阳性表达率明显低于癌旁组织,差异有统计学意义(P<0.05);不同性别、年龄、肺腺癌亚型及有无吸烟史的患者组织MnSOD、SIRT3表达差异无统计学意义(P>0.05),但随着组织学分级增加,肺腺癌组织MnSOD、SIRT3阳性表达率明显下降,TNM分期为Ⅲ期患者肺腺癌组织MnSOD、SIRT3阳性表达率明显低于Ⅰ+Ⅱ期患者,差异有统计学意义(P<0.05);Cox回归分析显示,MnSOD阴性、SIRT3阴性、组织学分级Ⅲ级、淋巴结转移、TNM分期Ⅲ期均是影响肺腺癌患者生存的独立危险因素;MnSOD、SIRT3阴性患者累积生存率明显低于MnSOD、SIRT3阳性患者,差异有统计学意义(P<0.05)。结论肺腺癌患者肺腺癌组织存在MnSOD、SIRT3低表达现象,并与组织学分级、淋巴结转移、TNM分期及生存密切相关。