Protective role for nitric oxide during the endoplasmic reticulum stress response in pancreatic β-cells
Protective role for nitric oxide during the endoplasmic reticulum stress response in pancreatic β-cells
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DOI：
10.1152/ajpendo.00620.2006
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发表时间：
2007-06-01
影响因子：
5.1
通讯作者：
Gaskins, H. Rex
中科院分区：
文献类型：
--
作者：
Kitiphongspattana, Kajorn;Khan, Tarannum A.;Gaskins, H. Rex
专职分泌细胞对二硫键形成的更高要求可能影响细胞内氧化还原稳态，特别是在内质网（ER）应激反应期间。为了评估这一假设，我们研究了ER应激反应对主要氧化还原对（GSH/ GSSG）、内源性ROS产生、参与ER氧化蛋白折叠的基因表达、一般抗氧化防御和巯基代谢的影响，通过使用经充分验证的MIN 6 β细胞作为模型和小鼠胰岛。数据显示，通过在小鼠胰岛中用特异性蛋白酶体抑制剂lactacystin（10 μ M）抑制ER相关降解诱导的ER衍生的氧化应激，GSH/ GSSG比率的葡萄糖浓度依赖性降低进一步显著降低。值得注意的是，在12小时处理期间观察到最小的细胞死亡。这可能归因于编码谷胱甘肽合成限速酶（γ-谷氨酰半胱氨酸连接酶）的基因以及参与抗氧化防御（谷胱甘肽过氧化物酶，过氧化物酶1）和ER蛋白折叠（Grp 78/ BiP，PDI，Ero 1）的基因的上调。用NO合酶抑制剂（N-ω-硝基-L-精氨酸甲酯，1 - 10 mM）进行的基因表达和报道基因测定表明内源性NO产生对于几种ER应激反应基因的上调是必需的。具体地说，凝胶位移分析证明了在MIN 6细胞中转录因子NF-E2相关因子与抗氧化反应元件Gclc-ARE 4的NO非依赖性结合.然而，内源性NO的产生是激活Gclc-ARE 4驱动的报告基因表达所必需的。总之，这些数据揭示了NO在ER应激反应期间的独特保护作用，其有助于消散ROS并促进β细胞存活。
Higher requirements for disulfide bond formation in professional secretory cells may affect intracellular redox homeostasis, particularly during an endoplasmic reticulum ( ER) stress response. To assess this hypothesis, we investigated the effects of the ER stress response on the major redox couple ( GSH/ GSSG), endogenous ROS production, expression of genes involved in ER oxidative protein folding, general antioxidant defense, and thiol metabolism by use of the well-validated MIN6 beta-cell as a model and mouse islets. The data revealed that glucose concentration- dependent decreases in the GSH/ GSSG ratio were further decreased significantly by ER-derived oxidative stress induced by inhibiting ER- associated degradation with the specific proteasome inhibitor lactacystin ( 10 mu M) in mouse islets. Notably, minimal cell death was observed during 12- h treatments. This was likely attributed to the upregulation of genes encoding the rate limiting enzyme for glutathione synthesis (gamma-glutamylcysteine ligase), as well as genes involved in antioxidant defense ( glutathione peroxidase, peroxiredoxin1) and ER protein folding ( Grp78/ BiP, PDI, Ero1). Gene expression and reporter assays with a NO synthase inhibitor ( N-omega-nitro- L-arginine methyl ester, 1 - 10 mM) indicated that endogenous NO production was essential for the upregulation of several ER stress- responsive genes. Specifically, gel shift analyses demonstrate NO- independent binding of the transcription factor NF- E2- related factor to the antioxidant response element Gclc- ARE4 in MIN6 cells. However, endogenous NO production was necessary for activation of Gclc- ARE4- driven reporter gene expression. Together, these data reveal a distinct protective role for NO during the ER stress response, which helps to dissipate ROS and promote beta- cell survival.