Glutathione peroxidase 7 protects against oxidative DNA damage in oesophageal cells.
Glutathione peroxidase 7 protects against oxidative DNA damage in oesophageal cells.
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DOI：
10.1136/gutjnl-2011-301078
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发表时间：
2012-09
期刊：
影响因子：
24.5
通讯作者：
El-Rifai W
中科院分区：
文献类型：
--
作者：
Peng D;Belkhiri A;Hu T;Chaturvedi R;Asim M;Wilson KT;Zaika A;El-Rifai W
食管粘膜暴露于胃酸和胆汁酸导致活性氧（ROS）蓄积，这是Barrett食管（BO）和进展为食管腺癌（OAC）的已知风险因素。在这项研究中，我们研究了谷胱甘肽过氧化物酶7（GPX 7），经常沉默OAC的功能，其调节活性氧和相关的氧化DNA损伤的能力。使用体外细胞模型，我们进行了包括GPX活性、Amplex UltraRed、CM-H2 DCFDA、膜联蛋白-V、8-氧代鸟嘌呤、磷酸-H2 A.X、定量实时PCR和蛋白质印迹测定的实验。酶促分析表明重组GPX 7蛋白具有有限的GPX活性。然而，GPX 7表现出很强的能力，中和H2 O2的谷胱甘肽独立。GPX 7在永生化BO细胞、BAR-T和CP-A中表达的重建导致对H2 O2诱导的氧化应激的抗性。在暴露于酸性胆汁酸混合物（pH 4）后，这些表达GPX 7的细胞表现出较低水平的H2 O2、细胞内ROS、氧化性DNA损伤和双链断裂（DSB），与对照相比（P<0.01）。此外，这些细胞表现出较低水平的ROS信号传导，通过减少磷酸化JNK（Thr 183/Tyr 185）和磷酸化p38（Thr 180/Tyr 182），并表现出较低水平的细胞凋亡后暴露于酸性胆汁酸或H2 O2诱导的氧化应激。内源性GPX 7基因敲减后，永生化食管鳞状上皮细胞（HET 1A）中H2 O2、细胞内ROS、DNA氧化损伤、DSB、细胞凋亡和ROS依赖性信号水平均显著升高（P<0.01），证实GPX 7对pH 4胆汁酸的保护作用。食管细胞中GPX 7的功能障碍增加了ROS和氧化DNA损伤的水平，这是BO和OAC的常见风险因素。
Exposure of the oesophageal mucosa to gastric acid and bile acids leads to accumulation of reactive oxygen species (ROS), a known risk factor for Barrett’s oesophagus (BO) and progression to oesophageal adenocarcinoma (OAC). In this study we investigated the functions of glutathione peroxidase 7 (GPX7), frequently silenced in OAC, and its capacity in regulating ROS and its associated oxidative DNA damage. Using in vitro cell models, we performed experiments that included GPX activity, Amplex UltraRed, CM-H2DCFDA, Annexin-V, 8-oxoguanine, phospho-H2A.X, quantitative real-time PCR and Western blot assays. Enzymatic assays demonstrated a limited GPX activity of the recombinant GPX7 protein. However, GPX7 exhibited a strong capacity to neutralize H2O2 independent of glutathione. Reconstitution of GPX7 expression in immortalized BO cells, BAR-T and CP-A, led to resistance to H2O2-induced oxidative stress. Following exposure to acidic bile acids cocktail (pH 4), these GPX7-expressing cells demonstrated lower levels of H2O2, intracellular ROS, oxidative DNA damage and double strand breaks (DSB), as compared to control (P<0.01). In addition, these cells demonstrated lower levels of ROS signaling, indicated by reduced phospho-JNK (Thr183/Tyr185) and phospho-p38 (Thr180/Tyr182), and demonstrated lower levels of apoptosis following the exposure to acidic bile acids or H2O2-induced oxidative stress. The knockdown of endogenous GPX7 in immortalized oesophageal squamous epithelial cells (HET1A) confirmed the protective functions of GPX7 against pH4 bile acids by showing an increase in the levels of H2O2, intracellular ROS, oxidative DNA damage, DSB, apoptosis and ROS-dependent signaling (P<0.01). The dysfunction of GPX7 in oesophageal cells increases the levels of ROS and oxidative DNA damage which are common risk factors for BO and OAC.
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影响因子：
4.8
作者：
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通讯作者：
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DOI：
10.1016/j.mrfmmm.2003.07.005
发表时间：
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