Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

Helicobacter pylori(H.pylori)infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue(MALT).Increasing evidence shows that eradication of H.pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission.The eradication of H.pylori is the standard care for patients with gastric MALT lymphoma.Cytotoxin-associated gene A(CagA)protein,one of the most extensively studied H.pylori virulence factors,is strongly associated with the gastric MALT lymphoma.CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races.After being translocated into B lymphocytes via typeⅣsecretion system,CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and-independent manners and/or some other pathways,and thereby promotes lymphomagenesis.A variety of proteins including p53and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA.Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma.

Cryptotanshinone inhibits cytotoxin-associated gene A-associated development of gastric cancer and mucosal erosions

BACKGROUND Approximately 90%of new cases of noncardiac gastric cancer(GC)are related to Helicobacter pylori(H.pylori),and cytotoxin-associated gene A(CagA)is one of the main pathogenic factors.Recent studies have shown that the pharmacological effects of cryptotanshinone(CTS)can be used to treat a variety of tumors.However,the effects of CTS on H.pylori,especially CagA+strain-induced gastric mucosal lesions,on the development of GC is unknown.AIM To assess the role of CTS in CagA-induced proliferation and metastasis of GC cells,and determine if CagA+H.pylori strains causes pathological changes in the gastric mucosa of mice.METHODS The effects of CTS on the proliferation of GC cells were assessed using the Cell Counting Kit-8(CCK-8)assay,and the abnormal growth,migration and invasion caused by CagA were detected by CCK-8 and transwell assays.After transfection with pSR-HA-CagA and treatment with CTS,proliferation and metastasis were evaluated by CCK-8 and transwell assays,respectively,and the expression of Src homology 2(SH2)domain–containing phosphatase 2(SHP2)and phosphorylated SHP2(p-SHP2)was detected using western blotting in AGS cells.The enzymelinked immunosorbent assay was used to determine the immunoglobulin G(IgG)level against CagA in patient serum.Mice were divided into four groups and administered H.pylori strains(CagA+or CagA-)and CTS(or PBS)intragastrically,and establishment of the chronic infection model was verified using polymerase chain reaction and sequencing of isolated strains.Hematoxylin and eosin staining was used to assess mucosal erosion in the stomach and toxicity to the liver and kidney.RESULTS CTS inhibited the growth of GC cells in dose-and time-dependent manners.Overexpression of CagA promoted the growth,migration,and invasion of GC cells.Importantly,we demonstrated that CTS significantly inhibited the CagAinduced abnormal proliferation,migration,and invasion of GC cells.Moreover,the expression of p-SHP2 protein in tumor tissue was related to the expression of IgG against CagA in the serum of GC patients.Additionally,CTS suppressed the protein expression levels of both SHP2 and p-SHP2 in GC cells.CTS suppressed CagA+H.pylori strain-induced mucosal erosion in the stomach of mice but had no obvious effects on the CagA-H.pylori strain group.CONCLUSION CTS inhibited CagA-induced proliferation and the epithelial-mesenchymal transition of GC cells in vitro,and CagA+H.pylori strains caused mucosal erosions of the stomach in vivo by decreasing the protein expression of SHP2.

幽门螺杆菌空泡细胞毒素(Vacuolating cytotoxin,VacA)研究进展

1988年Leunk等发现幽门螺杆菌(Helicobacter pylori,H.pylori)肉汤培养基的上清液含有一种使多种体外培养的真核细胞系发生空泡样变性的毒素,1992年这种毒素得以纯化并被命名为空泡细胞毒素(Vacuo-1ating cytotoxin,VacA).1994年完成了编码VacA的基因vacA的克隆和序列分析,由此VacA作为H.pylori致病的主要毒力因子引起了研究者的广泛兴趣和关注,本文将综述近十年有关VacA的研究进展.

Meta-analysis of the relationship between cytotoxin-associated gene-A and ischemic stroke subtypes

OBJECTIVE： To assess the role of cytotoxin-associated gene-A （CagA） positive strains of Helicobacter pylori （Hp） in ischemic stroke （IS） subtypes. DATA SOURCES： A computer-based online search of PubMed, EMBASE, the Cochrane Collaboration database, the CNKI database and the VIP database, from January 1997 to July 2010, was performed to find relevant studies. DATA SELECTION： Case-control studies relevant to CagA with IS and IS subtypes were selected. Data regarding related factors in the case group and control group were acquired using the same approach. All patients had been diagnosed as exhibiting IS using skull CT or MRI, and were etiologically typed according to the 1993 TOAST diagnosis criteria. Two investigators independently performed the same search and study selection. Meta-analyses were then performed for the selected studies using RevMan 5.0 software （Cochrane Collaboration） after strict screening. Heterogeneity tests, sensitivity analyses and publication bias assessments were then conducted. MAIN OUTCOME MEASURES： Relationship of CagA with IS and IS subtypes. RESULTS： Eight studies were selected, involving data from 879 patients with IS, and 849 healthy controls. Five out of eight of the selected studies were related to large artery atherosclerosis （461 patients with IS and 497 health controls）. The results of our meta-analysis revealed a significant association between prior infection with CagA-positive strains and increased risk of IS （odds ratio （OR） = 2.31,95% confidence interval （C/）： 1.89-2.82, P 〈 0.01）, In addition, we found an association between infection with CagA-negative strains and IS （OR = 0.57, 95%C1：0.47 0.70, P 〈 0.01）. CagA positive and negative strains were found to correlate with large artery atherosclerosis （CagA-positive strains： OR = 2.87, 95%C/： 2.19-3.77, P 〈 0.01; CagA-negative strains： OR = 0.51, 95%CL 0.39 0.67, P 〈 0.01）. Because of the diversity of etiological factors in the case-control study, we conducted further analyses after correcting for confounding factors, and the overall effects were recalculated. The results revealed significant relationships between CagA-positive strains and IS （OR = 2.36, 95%C1： 1.84-3.02, P 〈 0.01）, and between CagA-positive strains and large artery atherosclerosis （OR = 3.10, 95%C1： 2.29-4.19, P 〈 0.01 ）. A heterogeneity test of CagA-positive strains in IS and its subtypes revealed good homogeneity （f = 0%; f = 0%） and we adopted a fixed-effects model to calculate OR. Sensitivity analysis confirmed that the results of the meta-analysis were reliable. However, the funnel plot suggested that the experimental results may be affected by bias, possibly resulting from a lack of published studies reporting negative outcomes in the meta-analysis. CONCLUSION： Infection with CagA-positive strains is a risk factor for IS, especially the large artery atherosclerosis subtype. However, the evidence from case-control studies is weak, and more prospective studies are required to conclusively determine whether infection by CagA-positive strains should be considered a novel risk factor for IS and its subtypes.

Relationship between the cytotoxin-associated gene-A status of H pylori strains and cerebral infarction in European Caucasians and Chinese Han: A meta-analysis

AIM:To study the relationship between the cytotoxin-associated gene-A (CagA) status of H pylori strains and cerebral infarction among European Caucasians and Chinese Han by conducting a meta-analysis. METHODS:Ten case-control studies, with data on a total of 907 cases and 966 controls, were retrieved and considered;disqualified studies were excluded. The included studies were then tested for heterogeneity, and a meta-analysis was performed. RESULTS:The combined data revealed CagA-bearing strains of H pylori which cause chronic infection are associated with an increased risk of cerebral infarction (OR = 2.66, 95% CI:2.17-3.26), but no such relationship was found with CagA-negative strains (OR = 0.74, 95% CI:0.49-1.10) in the overall population. We performed subgroup analyses, dividing the overall population into European Caucasians and Chinese Han subgroups, and analyzed the studies according to their subgroup classification. Through the subgroup analysis, an association between cerebral infarction and CagA-bearing strains was found in both subgroups (OR = 2.60, 95% CI:1.93-3.49 in Chinese Han;OR = 2.71, 95% CI:2.05-3.59 in European Caucasians), but no significant association was found between cerebral infarction and CagA-negative strains (OR = 0.81, 95% CI:0.45-1.48 in Chinese Han;OR = 0.64, 95% CI:0.37-1.09 in European Caucasians).CONCLUSION:These results suggest CagA-bearing strains of H pylori are significantly associated with susceptibility to cerebral infarction in Chinese Han and European Caucasians, but that CagA-negative strains are not a definite predisposing factor in either subgroup. The magnitude of this association with cerebral infarction needs to be confirmed by prospective studies and combined studies of H pylori eradication.

Effect of NaCI and Helicobacter pylori vacuolating cytotoxin on cytokine expression and viability

瞄准：决定是否 Helicobacter pylori (H pylori ) vacuolating 细胞毒素(VacA ) 调整支持 inflammatory cytokines (IL-1beta， IL-8， TNF-alpha，和 IL-6 ) 的版本或改变胃的上皮的房间生存能力并且决定 NaCl 是否影响这些导致 VacA 的变化。方法：Vacuolating 活动被测量中性红的举起进对待 VacA 的人的液泡决定胃上皮(AGS ) 房间。AGS 房间生存能力被直接房间数估计。特定的连接酶的免疫吸着剂试金(ELISA ) 和反向的 transcriptase 聚合酶链反应(RT-PCR ) 被执行在 AGS 房间在房间支持 inflammatory cytokine 生产上检验 H pylori VacA 和 NaCl 的效果。从蒙古的沙鼠胃的织物染色的 Immunohistochemical 被用来在这导致 VacA 的回答上证实导致 VacA 的支持 inflammatory cytokine 生产和 NaCl 的效果。结果：VacA 的增加独自减少了 AGS 房间生存能力(P 【 0.05 ) ，并且这减小被 NaCl 的高剂量提高(P 【 0.05 ) 。VacA 独自导致了 TNF-alpha， IL-8 和 IL-1beta 的表示，当 NaCl 独自导致了 TNF-alpha 和 IL-1beta 的表示时。在 mRNA 层次的变化面对 VacA 和 NaCl 是更复杂的。为 TNF-alpha 的盒子，表示是 NaCl 上的剂量依赖者。IL-6 mRNA 没被检测。然而， IL-6 的底层被 ELISA 检测。IL-1， IL-6，和 TNF-alpha 的组织化学的染色在 H 感染 pylori 的沙鼠的胃的织物被发现的积极免疫用一本正常食谱或高盐喂了饮食。然而，染色这三 cytokines 在用 5 g/kg NaCl 食谱喂的 H 感染 pylori 的动物是更强壮的。结论：VacA 减少 AGS 房间的生存能力，和这效果能被 NaCl 提高。NaCl 也影响 VacA 导致的支持 inflammatory cytokines 的生产，建议 NaCl 起在 H 导致 pylori 的胃的上皮的房间细胞毒性的一个重要作用。

Mutation of cytotoxin-associated gene A affects expressions of antioxidant proteins of Helicobacter pylori

AIM: To determine if disruption of the cagA gene of Helicobacter pylori (H pylori) has an effect on the expression of other proteins at proteome level. METHODS: Construction of a cagA knock out mutant Hp27 _△cagA (cagA -) via homologous recombination with the wild-type strain Hp27 (cagA+) as a recipient was performed. The method of sonication-urea-CHAPS-DTT was employed to extract bacterial proteins from both strains. Soluble proteins were analyzed by two-dimensional electrophoresis (2-DE). Images of 2-DE gels were digitalized and analyzed. Only spots that had a statistical signif icance in differential expression were selected and analyzed by matrix-assisted laser desorption/ionizationtime of flight mass spectrometry (MALDI-TOF-MS). Biological information was used to search protein database and identify the biological function of proteins. RESULTS: The proteome expressions between wild-type strain and isogenic mutant with the cagA gene knocked-out were compared. Five protein spots with high abundance in bacteria proteins of wild-type strains, down-regulated or absently expressed in bacteria proteins of mutants, were identified and analyzed. From a quantitative point of view, the identified proteins are related to the cagA gene and important antioxidant proteins of H pylori , including alkyl hydroperoxide reductase (Ahp), superoxide dismutase (SOD) and modulator of drug activity (Mda66), respectively, suggesting that cagA is important to maintain the normal activity of antioxidative stress and ensure H pylori persistent colonization in the host. CONCLUSION: cagA gene is relevant to the expressions of antioxidant proteins of H pylori, which may be a novel mechanism involved in H pylori cagA pathogenesis.

幽门螺杆菌诱导上皮-间质转化在胃癌中的作用机制

幽门螺杆菌(Helicobacter pylori,Hp)是一种单极、微需氧、多鞭毛、螺旋形的革兰氏阴性菌,可在人胃黏膜上存活并定植。Hp作为与胃癌相关的Ⅰ类致癌物,其对胃黏膜的长期刺激可导致萎缩性胃炎、消化性溃疡、胃癌和胃黏膜相关淋巴组织淋巴瘤等多种疾病。研究表明,Hp感染可诱导胃上皮细胞发生上皮-间质转化(epithelial-mesenchymal transition,EMT),而EMT的异常调控则会导致胃癌发生。本文就Hp诱导胃上皮细胞发生EMT致胃癌的相关机制研究展开综述,为胃癌的早期诊断和靶向治疗提供新思路。

幽门螺杆菌东亚型菌株GZ7/cagA^(+)和GZ7/ΔcagA源外膜囊泡的蛋白组学比较

目的通过分离、鉴定和比较细胞毒素相关基因A蛋白(cagA)、阳性幽门螺杆菌(H.pylori)、东亚型菌株GZ7/cagA^(+)及其cagA敲除菌株GZ7/ΔcagA来源的外膜囊泡(OMVs)中的差异表达蛋白(DEPs),分析cagA基因对OMVs中蛋白表达的影响。方法采用超速离心法分别提取GZ7/ΔcagA和GZ7/cagA^(+)的OMVs,通过透射电镜和纳米颗粒追踪技术鉴定其形态和粒径,使用Western blot技术验证两组OMVs中cagA蛋白的表达,分析OMVs的蛋白质组学;对蛋白组学数据进行质控分析和主成分分析鉴定后,以上调蛋白倍数变化(FC)>2.0、下调蛋白FC<0.5,FDR≤0.05为筛选条件筛选DEPs,利用OmicsBean在线工具、Gene Ontology和KOBAS对DEPs进行生物信息学分析;采用免疫荧光鉴定OMVs细胞在细胞中的定位,实时无标记细胞分析仪检测细胞活性。结果通过电镜和粒径证实成功分离纯化了OMVs;蛋白质组分析发现,GZ7/cagA^(+)-OMVs组与GZ7/ΔcagA-OMVs组比较有79个DEPs,其中38个蛋白下调、41个蛋白上调;生物信息学分析显示,DEPs主要与丙酮酸代谢、丙酸代谢、糖酵解/糖异生及柠檬酸循环等代谢途径有关;免疫荧光和实时无标记细胞分析证实H.pylori来源的OMVs能进入细胞并定位在线粒体并抑制细胞增殖。结论cagA能影响H.pylori分泌的OMVs中蛋白质的成分,DEPs可能促进cagA^(+)H.pylori在胃黏膜上的定植及致病性。

幽门螺杆菌毒力因子CagA的基因表达调控机制研究进展

全球约有一半人口感染了幽门螺杆菌(Helicobacter pylori,H.pylori),特别是发展中国家的感染率极高。目前,幽门螺杆菌感染已被列为胃癌发生的高危因素。幽门螺杆菌感染的致病机制被认为与环境因素、宿主易感性和细菌毒力等因素之间复杂的相互作用有关。文章主要对幽门螺杆菌毒力因子细胞毒素相关基因(cytotoxin-associated gene A,cagA)表达调控的分子机制进行综述,以便更好地理解cagA的致病性,为今后预防和治疗由幽门螺杆菌所引起的疾病提供理论参考。

海南省39株幽门螺杆菌的耐药性及毒力基因特征

目的了解海南省幽门螺杆菌(Hp)耐药性及其毒力基因vacA、cagA和iceA基因型特征。方法对146例上消化道症状疾病患者进行胃镜检查,取胃黏膜组织进行Hp的分离和培养,对Hp进行药敏检测;通过聚合酶链式反应(PCR)对毒力基因cagA、vacA和iceA进行检测和分型,cagA测序进行聚类分析、并构建系统进化树;使用Fisher确切概率法分析各型毒力基因和患者疾病发生的相关性。结果共培养出39株Hp,对阿莫西林和克拉霉素的耐药率分别为2.6%和48.7%;39株均为vacA^(+)菌株,iceA 1型26株、2型13株;33株为cagA^(+)菌株,其中5株为西方型(EPIYA-ABC型),28株为东亚型(EPIYA-ABD型);cagA^(+)和vacA^(+)菌株与胃和十二指肠疾病有显著的相关性(P<0.05),iceA则无显著性差异(P>0.05)。结论海南省胃和十二指肠Hp患者中Hp毒力基因多样化,vacA s1am2/cagA^(+)基因型在消化性溃疡患者中占优势,不同毒力基因型对胃和十二指肠疾病的发生具有明显的差别,阿莫西林可作为该地区根除Hp首选抗生素。

Cytotoxin-associated gene-A-seropositive virulent strains of Helicobacter pylori and atherosclerotic diseases： a systematic review

Objective A systematic meta-analysis was performed to explore the role of cytotoxin-associated gene-A （CagA） seropositive strains of Helicobacter pylori （H. pylon） in the pathogenesis of atherosclerotic diseases. Data sources Data from Medline, EMBASE, CBMdisc, CNKI and the Cochrane Collaboration database were searched. Similar search strategies were applied to each of these databases. Study selection The review was restricted to the case-control studies on infective, chronic virulent CagA strains of H. pylori, involving the risk of ischemic stroke and coronary heart disease, ineligible studies were excluded. Two reviewers independently extracted the data and assessed study quality. Results Totally 26 case-control studies （11 studies on ischemic stroke and 15 studies on coronary heart disease） were retrieved and considered. The combined data revealed that the chronic seropositive virulent strains of H. pylori infection had a trend of increasing the risk of ischemic strokes and coronary heart diseases, yielding pooled ORs of 2.68 （95% CI： 2.20, 3.27） and 2.11 （95% CI： 1.70, 2.62）, respectively. We also performed subgroup analyses, dividing the total population into Caucasian and Chinese subgroups. Through the subgroup analysis, no significant difference was found between the subgroups. Conclusions Our results support the hypothesis that CagA-seropositive strains infection is significantly associated with susceptibility to ischemic strokes and coronary heart diseases. The magnitude of the association with atherosclerotic diseases needs to be confirmed by prospective studies and the studies on CagA-seropositive strains eradication are more important.

CagA阳性幽门螺杆菌感染与中年无症状人群CIMT相关性研究

目的探讨细胞毒素相关蛋白A(cytotoxin-associated protein A,CagA)阳性Hp感染与中年无症状人群颈动脉粥样硬化(carotid atherosclerosis,CAS)的相关性。方法选取在我院就诊的CAS患者578例作为CAS组,选取无CAS患者578例作为对照组,比较2组CagA阳性Hp感染比例,并作Logistic回归分析。比较CagA阳性Hp感染患者与CagA阴性患者颈动脉内-中膜厚度(carotid intima-media thick-ness,CIMT)。结果CAS组CagA阳性Hp感染患者比例高于对照组(P<0.05)。CagA阳性Hp感染是CAS的独立危险因素(OR=1.813,95%CI:1.379~2.384,P<0.05)。CagA阳性Hp感染患者CIMT大于CagA阴性患者(t=28.046,P<0.05)。结论在中年无症状人群中,CagA阳性Hp感染是CAS的独立危险因素,CagA阳性Hp感染患者CIMT大于CagA阴性Hp感染患者。因此,CagA阳性Hp感染与CAS的发生、发展有关。

眼镜蛇毒细胞毒素-1的分离纯化及其对HSC-LX2细胞PI3K/AKT 信号通路的影响

肝纤维化是多种刺激诱导的肝脏反复损伤的一种病理再生反应[1],其主要表征是肝脏中沉积着过量的细胞外基质(extracellular matrix,ECM)。ECM产生主要原因之一是由于肝星状细胞(hepatic stellate cell,HSC)被大量激活分化,磷脂酰肌醇-3-激酶/蛋白激酶B(PI3K/AKT)信号通路是一条重要的细胞内信号通路,能通过影响HSC的增殖和凋亡来调节肝纤维化[2-4]。

眼镜蛇细胞毒素致昆明小鼠局部皮肤坏死模型的构建

目的通过皮内注射中华眼镜蛇细胞毒素(CTX)建立中华眼镜蛇咬伤皮肤坏死小鼠模型。方法通过凝胶层析+离子层析从中华眼镜蛇粗毒中分离出眼镜蛇细胞毒素(CTX-X)。取30只小鼠随机分为10组:生理盐水组、10μg粗毒组、20μg粗毒组、25μg粗毒组、10μg CTX-X组、20μg CTX-X组、30μg CTX-X组、40μg CTX-X组、50μg CTX-X组、60μg CTX-X组,每组3只。注毒72 h后观察小鼠注射部位皮肤坏死直径及病理变化。结果(1)中华眼镜蛇粗毒通过Sephadex G-50凝胶层析分离获得2个蛋白峰(F1、F2),将CTX-X所在的F2峰经过CM Sepharose TM CL-6B阳离子交换柱色谱分离获得F1、F2、F3、F44个峰,通过小鼠体内实验及SDS-PAGE确定F4峰分离的CTX-X具有活性且达到电泳纯。(2)CTX-X组小鼠的皮内坏死直径随着CTX-X剂量增加而增大,51.21μg CTX-X组的小鼠皮内坏死直径均值达到5 mm。粗毒组小鼠随着皮内注射粗毒剂量的增加,小鼠72 h内的死亡率增高,当皮内注射粗毒剂量<25μg时,注毒72 h后处死并解剖小鼠,注射部位未观察到皮肤坏死情况;当皮内注射粗毒剂量≥25μg时,所有小鼠在注毒后3 h内死亡,且皮内注射部位未见明显坏死。结论应用Sephadex G-50凝胶过滤+CM Sepharose TM CL-6B阳离子交换分离所得的CTX-X,于小鼠背部皮内注射可成功构建中华眼镜蛇CTX-X致局部皮肤坏死的动物模型,该模型稳定性高且具备良好的可复制性。

Purification and partial amino acid sequences of a new presynaplic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus

The technique of the reverse-phase performance liquid chromatography (RP-HPLC) was employed to separate and purify the toxic proteins from the venom of Agkistrodon blomhoffii brevicaudus collected in China 3 toxic proteins marked as AgTx-1, AgTx-2 and AgTx-3 consisting of about 122 amino acid residues were screened The toxicities (LD50,) of the AgTx-1, AgTx-2 and AgTx-3 were 0.075, 0.51 and 6.6 mg per kg weight of mice respectively. Toxicological experiment in the chick biventer cervicis nerve-muscle preparation showed that the acetylcholine (Ach) sensitivity of the preparation was unchanged after the total failure of the indirect contraction caused by AgTx-1 and AgTx-2. suggesting that they were presynaptic blockers, namely β-type of snake toxins. However, the amplitude of indirect contraction of the preparation was gradually reduced due to its incomplete relaxation caused by AgTx-3, indicating that it should belong to the category of cytotoxins. The partial amino acid sequences of 3 toxins have

Impact of Helicobacter pylori virulence markers on clinical outcomes in adult populations

BACKGROUND In recent years,associations between specific virulence markers of Helicobacter pylori(H.pylori)and gastrointestinal disorders have been suggested.AIM To investigate the presence of virulence factors including vacuolating cytotoxin A genotypes(s1m1,s1m2,s2m1,and s2m2),cytotoxin-associated gene A(CagA),and urease activity in H.pylori strains isolated from Arab and Jewish populations in northern Israel and to assess associations between these factors and patients’demographics and clinical outcomes.METHODS Patients(n=108)who underwent gastroscopy at the Baruch Padeh Medical Center,Poriya due to symptomatic gastroduodenal pathologies as part of H.pylori diagnosis were enrolled in the study.Gastric biopsy specimens were collected from the antrum of the stomach.Clinical condition was assessed by clinical pathology tests.Bacteria were isolated on modified BD Helicobacter Agar(BD Diagnostics,Sparks,MD,United States).Bacterial DNA was extracted,and PCR was performed to detect CagA and vacuolating cytotoxin A genes.Urease activity was assessed using a rapid urease test.RESULTS A significant correlation was found between disease severity and patient ethnicity(P=0.002).A significant correlation was found between CagA presence and the s1m1 genotype(P=0.02),which is considered the most virulent genotype.Further,a higher level of urease activity was associated with isolates originating from the Jewish population.Moreover,higher urease activity levels were measured among CagA-/s1m1 and CagA-/s2m2 isolates.CONCLUSION Our study highlights the importance of incorporating molecular methods for detection of virulence markers of H.pylori in order to tailor optimal treatments for each patient.Further investigation should be performed regarding associations between H.pylori virulence factors and ethnicity.

Restoration of Mitochondrial Structure and Function within Helicobacter pylori VacA Intoxicated Cells

The Helicobacter pylori vacuolating cytotoxin (VacA) is an intracellular, mitochondrial-targeting exotoxin that rapidly causes mitochondrial dysfunction and fragmentation. Although VacA targeting of mitochondria has been reported to alter overall cellular metabolism, there is little known about the consequences of extended exposure to the toxin. Here, we describe studies to address this gap in knowledge, which have revealed that mitochondrial dysfunction and fragmentation are followed by a time-dependent recovery of mitochondrial structure, mitochondrial transmembrane potential, and cellular ATP levels. Cells exposed to VacA also initially demonstrated a reduction in oxidative phosphorylation, as well as increase in compensatory aerobic glycolysis. These metabolic alterations were reversed in cells with limited toxin exposure, congruent with the recovery of mitochondrial transmembrane potential and the absence of cytochrome c release from the mitochondria. Taken together, these results are consistent with a model that mitochondrial structure and function are restored in VacA-intoxicated cells.

中华眼镜蛇细胞毒素致小鼠局部皮肤溃疡模型的构建研究

目的:探讨不同部位皮下注射中华眼镜蛇细胞毒素(CTX)致小鼠局部皮肤溃疡模型构建。方法:将57只小鼠随机分为5组:CTX组(n=18)、粗毒组(n=18)、CTX前肢组(n=7)、CTX后肢组(n=7)和CTX背部组(n=7),饲养21天观察皮肤溃疡坏死面积及病理变化。结果:CTX组造模成功率100%,粗毒组造模成功率仅5.5%。选择四肢皮肤注射CTX造模较背部成功率更高,不同注射部位溃疡伤口均可见典型炎症坏死表现。结论:CTX皮下注射小鼠后肢可构建成功率高,稳定,典型的中华眼镜蛇毒素中毒局部皮肤溃疡模型。

幽门螺杆菌及其毒力因子空泡细胞毒素A对人胃腺癌细胞DNA同源重组修复和细胞周期的影响

目的研究幽门螺杆菌(Hp)标准株Hp P12和其毒力因子空泡细胞毒素A(VacA)对人胃腺癌细胞DNA损伤、同源重组修复和细胞周期的影响。方法取对数生长期的人胃腺癌AGS细胞,应用Hp标准株(Hp P12)和其VacA基因敲除株(Hp P12ΔVacA)以感染复数(multiplicity of infection,MOI)100分别感染AGS细胞,使用Western Blot方法检测DNA损伤标记蛋白γH2AX、HR修复关键蛋白(Rad51、CtIP、pCtIP)、细胞周期检测点激酶2(pCHK2)的表达水平,进一步用流式细胞术检测细胞周期,验证Hp P12及其毒力因子VacA对HR修复和细胞周期的影响。结果DNA损伤标记蛋白γH2AX的表达,在Hp P12感染组较未感染组上调(6 h:t=4.870,P=0.001;12 h:t=4.118,P=0.003),在Hp P12ΔVacA感染组较Hp P12感染组下调(6 h:t=4.669,P=0.002;12 h:t=3.117,P=0.013)。Rad51、CtIP、pCtIP和pCHK2的表达在Hp P12感染12 h组较未感染组下调(Rad51:t=22.740,P<0.001;CtIP:t=31.970,P<0.001;pCtIP:t=3.777,P=0.020;pCHK2:t=10.740,P<0.001),而Rad51、pCHK2的表达在Hp P12ΔVacA感染12 h组均较Hp P12感染12 h组上调(Rad51:t=5.637,P=0.005;pCHK2:t=3.726,P=0.006)CtIP的表达在Hp P12ΔVacA感染6 h组较Hp P12感染6 h组上调(t=4.580,P=0.002)。进一步采用流式细胞术检测细胞周期发现Hp P12感染组G 1期细胞数较未感染组下调(t=11.530,P<0.001),S期细胞数上调(t=8.583,P=0.001)。而Hp P12ΔVacA感染组G 1期细胞数较Hp P12感染组上调(t=5.781,P=0.004),S期细胞数下调(t=5.481,P=0.005)。结论Hp P12标准株感染人胃腺癌细胞后引起DNA损伤,抑制了细胞HR修复,并引起细胞周期阻滞,其中VacA毒力因子起到了重要作用。