Helicobacter pylori infection induces oxidative stress and programmed cell death in human gastric epithelial cells
Helicobacter pylori infection induces oxidative stress and programmed cell death in human gastric epithelial cells
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DOI：
10.1128/iai.00172-07
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发表时间：
2007-08-01
影响因子：
3.1
通讯作者：
Crowe, Sheila E.
中科院分区：
文献类型：
--
作者：
Ding, Song-Ze;Minohara, Yutaka;Crowe, Sheila E.
幽门螺杆菌感染与胃上皮细胞周转改变有关。为了评估氧化应激在细胞死亡中的作用，在没有或存在抗氧化剂的情况下，胃上皮细胞暴露于不同菌株的幽门螺杆菌、炎性细胞因子和过氧化氢中。通过氧化还原敏感的荧光染料、细胞色素C还原试验和谷胱甘肽的测定，检测到细胞内活性氧(ROS)的增加。通过检测DNA片段化和半胱氨酸天冬氨酸氨基转移酶(Caspase)活性评价细胞凋亡。感染幽门螺杆菌或将上皮细胞暴露在过氧化氢中会导致细胞凋亡和ROS生成的剂量依赖性增加，这种增加可以通过炎性细胞因子的预处理来增强。从幽门螺杆菌感染者的胃粘膜活检标本中分离的上皮细胞的ROS基础水平高于来自未感染个体的细胞。携带CAG致病岛(PAI)的幽门螺杆菌菌株比同基因CAG致病岛(PAI)突变株诱导更高水平的细胞内氧代谢产物。幽门螺杆菌感染和过氧化氢暴露导致caspase3和caspase8激活模式相似。抗氧化剂可抑制幽门螺杆菌产生ROS和DNA断裂。这些结果表明，在幽门螺杆菌感染过程中，细菌因素和宿主炎症反应对胃上皮细胞产生氧化应激，可能导致细胞凋亡。
Helicobacter pylori infection is associated with altered gastric epithelial cell turnover. To evaluate the role of oxidative stress in cell death, gastric epithelial cells were exposed to various strains of H. pylori, inflammatory cytokines, and hydrogen peroxide in the absence or presence of antioxidant agents. Increased intracellular reactive oxygen species (ROS) were detected using a redox-sensitive fluorescent dye, a cytochrome c reduction assay, and measurements of glutathione. Apoptosis was evaluated by detecting DNA fragmentation and caspase activation. Infection with H. pylori or exposure of epithelial cells to hydrogen peroxide resulted in apoptosis and a dose-dependent increase in ROS generation that was enhanced by pretreatment with inflammatory cytokines. Basal levels of ROS were greater in epithelial cells isolated from gastric mucosal biopsy specimens from H. pylori-infected subjects than in cells from uninfected individuals. H. pylori strains bearing the cag pathogenicity island (PAI) induced higher levels of intracellular oxygen metabolites than isogenic cag PAI-deticient mutants. H. pylori infection and hydrogen peroxide exposure resulted in similar patterns of caspase 3 and 8 activation. Antioxidants inhibited both ROS generation and DNA fragmentation by H. pylori. These results indicate that bacterial factors and the host inflammatory response confer oxidative stress to the gastric epithelium during H. pylori infection that may lead to apoptosis.