Helicobacter pylori γ-Glutamyl Transpeptidase Is a Pathogenic Factor in the Development of Peptic Ulcer Disease
Helicobacter pylori γ-Glutamyl Transpeptidase Is a Pathogenic Factor in the Development of Peptic Ulcer Disease
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DOI：
10.1053/j.gastro.2010.03.050
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发表时间：
2010-08-01
期刊：
影响因子：
29.4
通讯作者：
Ho, Bow
中科院分区：
文献类型：
--
作者：
Gong, Min;Ling, Samantha Shi Min;Ho, Bow
背景与目的：γ -谷氨酰转肽酶（GGT）已被报道为幽门螺杆菌的毒力因子，与细菌定植和细胞凋亡有关。但其发病机制尚不明确。本研究旨在探讨其在幽门螺杆菌介导感染中的作用。方法：采用聚合酶链反应（PCR）方法构建多种幽门螺杆菌等基因突变体。采用离子交换和凝胶过滤层析纯化幽门螺杆菌天然GGT蛋白（HP-nGGT）。荧光法测定H(2)O(2)的生成，荧光素酶法和Western blot法测定核因子κ B （nf - κ B）的活化。采用酶联免疫吸收法和实时荧光定量PCR检测细胞因子的产生。采用彗星法和流式细胞术评估DNA损伤。用酶法分析了98株幽门螺杆菌的GGT活性。结果：纯化后的HP-nGGT在原代胃上皮细胞和AGS胃癌细胞中产生H(2)O(2)，激活NF-kappa B，上调白细胞介素-8 （IL-8）的产生。此外，HP-nGGT引起8-OH-dG水平升高，表明DNA氧化损伤。与野生型相比，δ ggt细胞中H(2)O(2)生成、IL-8生成和DNA损伤水平显著降低（P < 0.05）。从消化性溃疡患者（n = 54）中分离出的幽门螺杆菌活性显著高于非溃疡性消化不良患者（n = 44），这表明GGT的临床重要性。结论：我们的研究结果证明GGT是幽门螺杆菌性消化性溃疡的致病因素。
BACKGROUND & AIMS: gamma-Glutamyl transpeptidase (GGT) has been reported to be a virulence factor of Helicobacter pylori associated with bacterial colonization and cell apoptosis. But its mechanism of pathogenesis is not firmly established. This study aims to examine its role in H pylori-mediated infection. METHODS: Various H pylori isogenic mutants were constructed by a polymerase chain reaction (PCR) approach. H pylori native GGT protein (HP-nGGT) was purified with ion-exchange and gel-filtration chromatography. Generation of H(2)O(2) was measured with fluorimetric analysis, whereas nuclear factor-kappa B (NF-kappa B) activation was determined by luciferase assay and Western blot. Cytokine production was examined by enzyme-linked immunoabsorbent assay and real-time PCR. DNA damage was assessed with comet assay and flow cytometry. The GGT activity of 98 H pylori isolates was analyzed by an enzymatic assay. RESULTS: Purified HP-nGGT generated H(2)O(2) in primary gastric epithelial cells and AGS gastric cancer cells, resulting in the activation of NF-kappa B and up-regulation of interleukin-8 (IL-8) production. In addition, HP-nGGT caused an increase in the level of 8-OH-dG, indicative of oxidative DNA damage. In contrast, Delta ggt showed significantly reduced levels of H(2)O(2) generation, IL-8 production, and DNA damage in cells compared with the wild type (P < .05). The clinical importance of GGT was indicated by significantly higher (P < .001) activity in H pylori isolates obtained from patients with peptic ulcer disease (n = 54) than isolates from patients with nonulcer dyspepsia (n = 44). CONCLUSION: Our findings provide evidence that GGT is a pathogenic factor associated with H pylori-induced peptic ulcer disease,