CagA对幽门螺杆菌诱导胃黏膜上皮细胞分泌IL-8水平的影响

目的：利用小分子干扰RNA（siRNA）探讨CagA在幽门螺杆菌诱导胃黏膜上皮细胞分泌IL-8中的作用。方法：设计5条siRNA,采用电穿孔法转入CagA+幽门螺杆菌NCTC11637,与胃黏膜上皮细胞共培养后测定IL-8水平,并以RT-PCR、Westernblotting法检测穿孔前、后不同时点细菌的CagA表达。采用CagA-株NCTC11639作对照。结果：CagA+NCTC11637诱导胃黏膜上皮细胞分泌IL-8水平明显高于CagA-NCTC11639［（1200.00±32.51)ng/Lvs(100.00±8.58）ng/L］（P<0.01）。siRNAⅢ转化的幽门螺杆菌诱导胃黏膜上皮细胞分泌IL-8水平显著低于转化前［(400.00±17.35)ng/Lvs（1200.00±32.51)ng/L］(P<0.05);siRNAⅢ转化的幽门螺杆菌CagAmRNA水平显著低于转化前,穿孔后6hmRNA水平最低为31.3%(0.270/0.861),抑制率为68.7%。Westernblotting显示siRNAⅢ组CagA蛋白水平低于穿孔前（P<0.01）;其余4条siRNA未见显著变化。结论：CagA在幽门螺杆菌诱导胃黏膜上皮细胞分泌IL-8中起重要作用,小分子干扰RNA可能通过抑制CagA基因表达而减少幽门螺杆菌诱导胃黏膜上皮细胞IL-8的分泌。     

幽门螺杆菌cagA菌株感染对IL-8蛋白在胃癌组织中表达的影响

目的 探讨胃癌组织中HpcagA菌株感染对IL-8蛋白表达的影响。方法 采用流式细胞技术，对27例胃癌及相应的癌旁正常组织中IL-8蛋白的表达进行定量检测，用PCR法，对27例胃癌组织中HpcagA基因进行扩增。结果 27例胃癌组织中中，有25例（92%）可明显表达IL-8蛋白；而相应的癌旁正常组织中，基本没有IL-8蛋白的表达或仅有弱相应的癌旁正常组织中，基本没有IL-8蛋白的表达或仅有弱表达，HpcagA感染的胃癌组织中，IL-8的表达水平为64.27%，高于未感染HpcagA的胃癌组织（39.86%)。结论 IL-8在胃癌组织中的高表达与HpcagA感染有关。即HpcagA菌株感染可上调IL-8在胃癌组织中的表达水平。     

Hp感染相关的胃上皮细胞IL—8的产生及致病机制

幽门螺旋杆菌（ Ｈｐ） 是胃炎、胃十二指肠溃疡、胃癌、胃淋巴瘤的重要致病因素。 Ｈｐ 诱导产生的 Ｉ Ｌ８ 作为第二信使招致粒细胞在局部聚集,是引起炎症反应以及进一步病理损害的重要调节因子。在 Ｈｐ 感染性胃疾病中,胃粘膜中的 Ｉ Ｌ８ 蛋白表达明显增加。     

幽门螺杆菌与十二指肠疾病及胃上皮化生的关系

研究幽门螺杆菌与十二指肠疾病及其胃上皮化生的关系。方法：应用特殊染色方法对１６６例胃窦及十二指肠活检标本进行了形态学观察及ＨＰ检测。     

幽门螺杆菌感染患者IL-8和TNF-α水平的检测

幽门螺杆菌 (Ｈｅｌｉｃｏｂａｃｔｅｒｐｙｌｏｒｉ,ＨＰ )感染可导致胃粘膜大量炎症细胞浸润及免疫反应 ,细胞因子增多[1] 。白细胞介素 8(ＩＬ 8)、肿瘤坏死因子α (ＴＮＦ α )均是具有介导炎症反应 ,参与免疫及内分泌调节等广泛生物学作用的细胞因子。本文对ＨＰ感染患者ＩＬ 8和ＴＮＦ α水平进行了检测 ,探讨其致病机制。1　材料和方法1 1　研究对象　经胃镜和组织学检查诊断为ＨＰ感染慢性胃炎 2 8例 ,男 18例 ,女 10例 ,平均年龄 4 2岁。正常对照组 12例 ,胃镜和组织学检查正常 ,ＨＰ阴性。1 2　方法　每例患者胃镜检查时在距幽门…     

幽门螺杆菌相关性消化道疾病血清IL-8,TNF-α和Gas测定及其临床意义

目的 :探讨HP感染慢性胃炎及十二指肠溃疡患者血清IL - 8、TNF -α及Gas水平变化与其发病的关系。方法 :选择1 4C -尿素呼气试验阳性及胃镜和病理组织学确诊的 35例慢性胃炎及 30例十二指肠溃疡患者 ,皆采用放射免疫分析测定其血清IL - 8、TNF -α及Gas水平。结果 :慢性胃炎组血清IL - 8、TNF -α及Gas均显著高于正常对照组 ,其血清IL - 8及Gas水平与对照组比较差异极显著 (p <0 0 1)。TNF -α与对照组比较也具统计学意义 (p <0 0 5 )。十二指肠溃疡组则三项指标均极显著高于正常对照组 (p <0 0 1)。两组间比较三项指标亦均呈极显著差异 (p <0 0 1)。结论 :HP感染的慢性胃炎及十二指肠溃疡患者三项指标均呈显著变化 ,证实两种消化系疾病的发生、发展与HP感染密切相关。     

幽门螺杆菌诱导人胃上皮细胞(GES-1)自噬的研究

 摘要:目的 观察幽门螺杆菌感染人胃上皮细胞后自噬的发生及变化情况,为进一步研究幽门螺杆菌感染后诱发自噬反应的相关研究奠定基础。方法 采用中性红摄入法确定H. pylori感染细胞的最佳浓度,以此浓度分别感染细胞,通过Western Blot检测感染不同时间LC3与p62的表达情况,免疫荧光染色检测自噬体。使用自噬抑制剂3MA、E64d、 pepstatin A干预后,观察感染后自噬变化情况。结果 H. pylori (22695) 感染GES-1细胞最佳浓度为m.o.i=400。感染后2小时即可观察到自噬的发生,且呈时间依赖性,于8小时到达高峰,24小时开始恢复基础水平。使用3MA阻断自噬,自噬体明显减少,且细胞形态欠佳。使用E64d和pepstatin A处理后自噬也受到一定程度的抑制。结论 H. pylori（22695）能够诱导人胃上皮（GES-1）发生自噬,且可被自噬抑制剂所抑制。     

小檗碱减轻幽门螺杆菌诱导的人胃黏膜上皮细胞损伤

目的:探讨小檗碱(Ber)对幽门螺杆菌(Hp)诱导的人胃黏膜上皮细胞GES-1损伤的保护作用及机制。方法:采用Hp感染GES-1细胞,加入小檗碱(5,10和20μmol/L)和细胞外调节蛋白激酶(ERK1/2)抑制剂PD98059(20μmol/L)共培养。MTT法检测细胞活力,流式细胞术检测细胞凋亡,ELISA法检测细胞白细胞介素(IL)-1β及IL-8的水平,比色法检测细胞乳酸脱氢酶(LDH)活性并以Western blot法检测细胞Bax、Bcl-2、p-ERK1/2的蛋白水平。结果:与对照组比较,Hp可抑制GES-1细胞活力、促进GES-1细胞凋亡、诱导GES-1细胞分泌IL-1β和IL-8、增加LDH活性、增加GES-1细胞内p-ERK1/2及Bax蛋白水平并降低Bcl-2蛋白水平,差异均有统计学显著性(P0.05);与Hp感染组比较,中、高剂量小檗碱均可逆转Hp对GES-1细胞活力、细胞凋亡、细胞IL-1β及IL-8分泌、LDH活性和GES-1细胞内p-ERK1/2、Bax及Bcl-2蛋白水平的影响,差异均有统计学显著性(P0.05);与高剂量小檗碱组比较,PD98059联合小檗碱可进一步逆转Hp对GES-1细胞上述指标的影响,差异均有统计学显著性(P0.05)。结论:小檗碱可通过抗炎、增加细胞活力和抗凋亡来减轻Hp诱导的GES-1细胞损伤,其机制可能与抑制ERK1/2通路有关。     

Induction of secretion of interleukin-8 from human gastric epithelial cells by heat-shock protein 60 homologue of Helicobacter pylori.

Escherichia coli cells expressing fusion proteins consisting of beta-galactosidase and bacterial heat-shock protein (HSP) 60 of E. coli, Yersinia enterocolitica or Helicobacter pylori were constructed, and designated as HY1, HY2 or HY3, respectively. Fusion proteins prepared from HY2 and HY3 induced secretion of interleukin-8 (IL-8) from human gastric epithelial KATOIII cell cultures. On the other hand, the parent strain (E. coli pop2136), PEX (pop2136 transformed by vector) and fusion protein prepared from HY1 did not induce IL-8 secretion from KATOIII cells. Other human gastric (MKN45) and non-gastric cell lines (Int 407 and A549) did not secrete IL-8 following treatment with these proteins. These results indicate that H. pylori HSP60 induces IL-8 secretion from human gastric cells and the levels of IL-8 differ among the various gastric cell lines, suggesting that HSP60 might be an important virulence factor associated with chronic gastric inflammation following H. pylori infection in man.     

Increased expression of interleukin-6 gene in gastritis and gastric cancer

Helicobacter pylori (H. pylori) induces an intense inflammatory response, mediated by proinflammatory cytokines, including interleukin (IL)-6 and its membrane receptor (IL-6R), which activates important signaling pathways in the development of gastric disease and cancer. We investigated the gene and protein expression of IL-6 and IL-6R and the influence of polymorphisms rs1800795, rs1800796, and rs1800797 on its gene expression together with H. pylori infection. Furthermore, an in-silico analysis was performed to support our results. Gastric biopsies were obtained from patients with gastric symptoms and patients with gastric cancer (GC) and were divided into groups (Control, Gastritis, and Cancer). H. pylori was detected by PCR. Real-time-qPCR was employed to determine gene expression, and western blot assay was used to analyze protein expression levels. PCR-RFLP was used to characterize IL-6 polymorphisms. Bioinformatics analyses were performed using the Gene Expression Omnibus (GEO) database and GEO2R to screen out differentially expressed genes (DEGs). H. pylori was detected in 43.3% of the samples. Statistically significant differences were found for IL-6 (P=0.0001) and IL-6R (P=0.0005) genes among the three groups, regardless of the presence of H. pylori. Among patients with H. pylori infection, the IL-6 and IL-6R gene and protein expressions were significantly increased, highlighting IL-6 gene overexpression in patients with GC. No statistically significant differences were found for the rs1800795, rs1800796, and rs1800797 polymorphisms compared to IL-6 gene expression. The results indicated that the IL-6 polymorphisms do not influence its expression, but IL-6 and IL-6R expression seems to be altered by the presence of H. pylori.     

Helicobacter pylori -induced apoptosis in gastric epithelial cells is blocked by protein kinase C activation

Apoptosis plays a major role in gastrointestinal epithelial cell turnover. We have examined induction of apoptosis by Helicobacter pylori in gastric AGS cells and the role of protein kinase C (PKC) which has been shown to modulate programmed cell death. Incubation of AGS cells with H. pylori resulted in an activation of caspases 3 and 9 and induced programmed cell death. The PKC activator 12- O -tetradecanoylphorbol-13-acetate (TPA) caused translocation of PKC gamma, delta and var epsilon, prevented H. pylori -induced caspase activation and programmed cell death. Cocultivation of AGS cells with H. pylori resulted in a translocation of the atypical PKC isoform PKC lambda. We suggest that inhibition of H. pylori induced apoptosis by PKC activation can play a role in the process of neoplastic transformation.     

固有免疫分子DC-SIGN在幽门螺杆菌感染胃黏膜上皮细胞表达意义

探讨固有免疫分子DC-SIGN在幽门螺杆菌(H.pylori)感染的胃上皮细胞表达,及其与胃黏膜损伤的关系.选取经胃镜及组织病理检查确诊的72例慢性胃炎患儿胃黏膜活检标本,采用免疫组化检测胃黏膜上皮细胞DC-SIGN表达.体外建立幽门螺杆菌感染胃上皮细胞模型,采用流式细胞术检测幽门螺杆菌刺激的胃上皮细胞DC-SIGN以...     

cagA基因阳性幽门螺杆菌培养滤液对人胃粘膜上皮细胞系GES-1生长的影响

目的：研究cagA^ 幽门螺杆菌（Hp）培养滤液对人胃粘膜上皮细胞（GES－1）的作用及机制。方法：制备Hp培养滤液，PCR鉴定cagA基因。采用倒置显微镜、电镜、细胞生长曲线、克隆形成实验、单细胞微凝胶电泳及流式细胞仪等，观察Hp (cagA^ ）培养滤液对GES－1细胞的作用。结果：经Hp(cagA^ )培养滤液处理GES－1细胞，细胞核增大、畸形、核染色质变粗、核仁肥大、核分裂。生长曲线可见细胞增生活跃，增殖率195％。克隆形成试验显示细胞克隆形成能力增强，增殖率达到337．5％。流式细胞仪S期细胞比率显著高于对照组。Hp(cagA^ ）培养滤液可使GES－1细胞形成彗星现象。结论：Hp(cagA^ )培养滤液可以导致GES－1细胞的生长特性改变，呈现肿瘤细胞的形态学及生长特征。DNA损伤可能是cagA诱导GES－1细胞生长特性改变的机制之一。     

Modes of Helicobacter colonization and gastric epithelial damage

A total of 144 gastric biopsies colonized by Helicobacter-like organisms were studied under light and differential interference contrast microscopy for the modes of bacterial colonization. Biopsies were also graded for the degree of epithelial damage (epithelial-damage-grade: 0 to 6, in ascending order of severity) and density of Helicobacter-like organism (Helicobacter-grade: 0 to 6, in ascending order of bacterial density). Three modes of colonization were identified: free-in-mucus, surface-adhesion and intercellular colonization. Because light microscopy cannot definitely prove the presence of intracellular colonization, bacteria located between cells and below the apical cell border were counted together as intercellular colonization. Bacteria free-in-mucus were seen in all biopsies. Surface adhesion was seen in 50-87.9% of biopsies, without obvious correlation with the epithelial-damage- and Helicobacter-grades. The incidences of intercellular and intracellular colonization were directly proportional to the epithelial-damage- and Helicobacter-grades. Free-in-mucus as the predominant mode of colonization was mainly seen in biopsies with lower (1-3) epithelial-damage- and Helicobacter-grades. Conversely, biopsies with intercellular colonization as the predominant mode of colonization were mainly cases with higher (4-6) epithelial-damage- and Helicobacter-grades. In cases showing predominantly bacteria between cells, 69.2% had a gastric ulcer whereas only 38.8% of cases showing predominantly bacteria free-in-mucus showed ulceration (P < 0.01). These results indicate that Helicobacter-like organisms can invade and penetrate between epithelial cells. When free-in-mucus, Helicobacter-like organisms are less likely to induce epithelial damage. However, the more invasive modes of colonization (intercellular) were associated with severe epithelial damage and high Helicobacter density.(ABSTRACT TRUNCATED AT 250 WORDS)     

CagA protein secreted by the intact type IV secretion system leads to gastric epithelial inflammation in the Mongolian gerbil model

Helicobacter pylori causes various gastro-duodenal diseases, including gastric cancer. The CagA protein, an H. pylori virulence factor, induces morphological changes in host cells and may be associated with the development of peptic ulcer and gastric carcinoma. The present study has analysed the role of CagA protein in the pathogenesis of H. pylori infection in the Mongolian gerbil model. Mongolian gerbils were challenged with wild-type H. pylori strain TN2, which has a functional cag pathogenicity island or isogenic mutants with disrupted cagA (DeltacagA) or cagE (DeltacagE) genes. They were sacrificed at 7, 13, and 25 weeks after inoculation. Pathological changes of the gastric mucosa were determined and apoptosis was assessed by the TUNEL assay. Immunohistochemistry for PCNA, phospho-IkappaBalpha, and phospho-Erk was also performed. All of the bacterial strains colonized the gerbil stomach at similar densities; however, the DeltacagA mutant induced milder gastritis than did the wild type. The extent of apoptosis and lymphoid follicle formation in the epithelium appeared to depend on intact cagA. The DeltacagA mutant induced less phosphorylation of IkappaBalpha and Erk, and less expression of interferon-gamma and interleukin-1beta mRNA in the epithelium than did the wild type. It is concluded that CagA protein may be essential for the induction of severe gastritis in the Mongolian gerbil model.     

幽门螺杆菌对体外培养的胃上皮细胞增殖与凋亡的影响

目的　研究H .pylori对体外培养的胃上皮细胞增殖与凋亡的影响。方法　以SGC 790 1细胞作为H .pylori感染的体外细胞模型 ,用Ki 6 7抗原的免疫组化分析检测了H .pylori标准菌株NCTC 116 37活菌对胃上皮细胞增殖的影响 ,同时用流式细胞术、荧光染色技术检测了细胞凋亡率。结果　H .pylori在较低浓度 (≤ 1.6× 10 5CFU/ml)时对细胞增殖有促进作用 ,而在较高浓度 (≥ 8× 10 5CFU/ml)时抑制细胞增殖。H .pylori以浓度依赖方式诱导胃上皮细胞凋亡 ,Hoechst 332 5 8荧光染色和流式细胞术两种方法所得结果一致。结论　细胞凋亡与增殖间的不平衡亦可部分解释人体感染H .pylori后所表现的多样化结局