Glutathione levels and BAX activation during apoptosis due to oxidative stress in cells expressing wild-type and mutant cystic fibrosis transmembrane conductance regulator
Glutathione levels and BAX activation during apoptosis due to oxidative stress in cells expressing wild-type and mutant cystic fibrosis transmembrane conductance regulator
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DOI：
10.1074/jbc.m110288200
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发表时间：
2002-08-02
影响因子：
4.8
通讯作者：
Ojcius, DM
中科院分区：
文献类型：
--
作者：
Jungas, T;Motta, I;Ojcius, DM
囊性纤维化的特征在于慢性炎症和肺泡和肺氧化剂和抗氧化剂浓度的不平衡，这导致细胞损伤。肺谷胱甘肽浓度的改变被认为是炎症性肺病如囊性纤维化的显著特征，谷胱甘肽在保护免受氧化应激中起主要作用，并且在调节细胞凋亡中很重要。囊性纤维化跨膜传导调节因子（CFTR）对Cl-、较大的有机离子以及还原和氧化形式的谷胱甘肽具有渗透性，并且在囊性纤维化患者中发现的DeltaF508 CFTR突变与囊性纤维化气道上皮中受损的谷胱甘肽转运相关。由于细胞内谷胱甘肽保护氧化应激诱导的细胞凋亡，我们研究了上皮细胞（HeLa和IB3 - 1）表达正常和突变CFTR的H2O2引发的细胞凋亡的易感性。我们发现CFTR正常的细胞对氧化应激诱导的凋亡比表达缺陷CFTR的细胞更敏感。此外，对细胞凋亡的敏感性可能与谷胱甘肽水平相关，因为细胞内谷胱甘肽的耗尽导致更高水平的细胞凋亡，并且在与H2O2孵育期间，表达正常CFTR的细胞中谷胱甘肽水平下降得比CFTR缺陷的细胞更快。在这些条件下，促凋亡BCL-2家族成员BAY在表达正常CFTR的细胞中也比在具有突变CFTR的细胞中更快地被激活，并且人工谷胱甘肽耗尽增加了BAX激活的程度。这些结果表明，谷胱甘肽依赖的BAX激活与正常CFTR的细胞代表了氧化应激诱导这些细胞凋亡的早期步骤。
Cystic fibrosis is characterized by chronic inflammation and an imbalance in the concentrations of alveolar and lung oxidants and antioxidants, which result in cell damage. Modifications in lung glutathione concentrations are recognized as a salient feature of inflammatory lung diseases such as cystic fibrosis, and glutathione plays a major role in protection against oxidative stress and is important in modulation of apoptosis. The cystic fibrosis transmembrane conductance regulator (CFTR) is permeable to Cl-, larger organic ions, and reduced and oxidized forms of glutathione, and the DeltaF508 CFTR mutation found in cystic fibrosis patients has been correlated with impaired glutathione transport in cystic fibrosis airway epithelia. Because intracellular glutathione protects against oxidative stress-induced apoptosis, we studied the susceptibility of epithelial cells (HeLa and IB3-1) expressing normal and mutant CFTR to apoptosis triggered by H2O2. We find that cells with normal CFTR are more sensitive to oxidative stress-induced apoptosis than cells expressing defective CFTR. In addition, sensitivity to apoptosis could be correlated with glutathione levels, because depletion of intracellular glutathione results in higher levels of apoptosis, and glutathione levels decreased faster in cells expressing normal CFTR than in cells with defective CFTR during incubation with H2O2. The pro-apoptotic BCL-2 family member, BAY, is also activated faster in cells expressing normal CFTR than in those with mutant CFTR under these conditions, and artificial glutathione depletion increases the extent of BAX activation. These results suggest that glutathione-dependent BAX activation in cells with normal CFTR represents an early step in oxidative stress-induced apoptosis of these cells.