Induction of glutathione synthesis in macrophages by oxidized low-density lipoproteins is mediated by consensus antioxidant response elements
Induction of glutathione synthesis in macrophages by oxidized low-density lipoproteins is mediated by consensus antioxidant response elements
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DOI：
10.1161/01.res.0000059561.65545.16
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发表时间：
2003-03-07
影响因子：
20.1
通讯作者：
Rosenfeld, ME
中科院分区：
文献类型：
--
作者：
Bea, F;Hudson, FN;Rosenfeld, ME
氧化低密度脂蛋白（oxLDL）的巨噬细胞的摄取，导致转化为泡沫细胞是动脉粥样硬化的一个种子事件。oxLDL的过度积累可引起泡沫细胞中的氧化应激，导致细胞死亡和动脉粥样硬化病变的进展和不稳定。氧化应激诱导内源性抗氧化剂谷胱甘肽（GSH）合成的保护性补偿性增加。谷氨酸-半胱氨酸连接酶（GCL）是谷胱甘肽合成的限速酶，由催化亚基（GCLC）和修饰亚基（GCLM）组成，它们是不同基因的产物。用oxLDL（30 μ g/mL）处理RAW 264.7小鼠巨噬细胞和小鼠腹膜巨噬细胞在体外诱导Gclc和Gclm表达增加。mRNA的增加部分地通过增加的转录发生，如荧光素酶报告基因构建体所证明的。GCLC和GCLM的启动子都含有共有的抗氧化反应元件（战神）。电泳迁移率变动分析显示，诱导核因子结合这些战神后处理的RAW 264.7细胞和小鼠腹腔巨噬细胞与oxLDL。核因子与战神的结合通过核心序列中的单个碱基对取代而减少。Gclc和Gclm启动子内战神的定点突变导致oxLDL诱导的荧光素酶活性降低。超移位分析表明，oxLDL刺激结合的转录因子Nrf 1，Nrf 2，和c-jun的ARE。这些数据表明战神在介导oxLDL诱导GSH合成和保护巨噬细胞免受氧化脂质诱导的氧化应激中发挥直接作用。
The uptake of oxidized low-density lipoproteins (oxLDL) by macrophages leading to conversion into foam cells is a seminal event in atherogenesis. Excessive accumulation of oxLDL can cause oxidative stress in foam cells leading to cell death and the progression and destabilization of atherosclerotic lesions. Oxidative stress induces a protective compensatory increase in the synthesis of the endogenous antioxidant glutathione (GSH). Glutamate-cysteine ligase (GCL) is the rate-limiting enzyme in GSH synthesis and is composed of a catalytic subunit (GCLC) and a modifier subunit (GCLM), which are products of separate genes. Treatment of RAW 264.7 mouse macrophages and mouse peritoneal macrophages with oxLDL (30 mug/mL) induces increased expression of both Gclc and Gclm in vitro. The increase in mRNA occurs in part via increased transcription as demonstrated with luciferase reporter constructs. The promoters for both GCLC and GCLM contain consensus antioxidant response elements (AREs). Electrophoretic mobility shift assays revealed induction of nuclear factor binding to these AREs after treatment of RAW 264.7 cells and mouse peritoneal macrophages with oxLDL. Nuclear factor binding to the AREs is diminished by a single base pair substitution in the core sequence. Site-directed mutagenesis of the AREs within the Gclc and Gclm promoters resulted in a decrease of oxLDL-induced luciferase activity. Supershift analyses revealed that oxLDL stimulates binding of the transcription factors Nrf1, Nrf2, and c-jun to the AREs. These data suggest that AREs play a direct role in mediating the induction of GSH synthesis by oxLDL and in protecting macrophages against oxidized lipid-induced oxidative stress.