Mechanisms of pyruvate inhibition of oxidant-induced apoptosis in human endothelial cells
Mechanisms of pyruvate inhibition of oxidant-induced apoptosis in human endothelial cells
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DOI：
10.1016/s0026-2862(03)00052-9
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发表时间：
2003-09-01
影响因子：
3.1
通讯作者：
Kang, YH
中科院分区：
文献类型：
--
作者：
Lee, YJ;Kang, IJ;Kang, YH
我们最近证明，氧化还原反应物丙酮酸可防止过氧化氢（H2O2）诱导的内皮细胞凋亡，其抗凋亡特性部分是通过线粒体室介导的。然而，对介导丙酮酸抗凋亡特性的分子信号通路知之甚少。在人脐静脉内皮细胞（HUVECs）中尝试用生化方法来阐明这种信号通路。比较了抗氧化丙酮酸与胞浆还原剂l -乳酸、氧化还原中性乙酸、苹果酸-天冬氨酸穿梭阻断剂氨基乙酸的抗氧化作用。内皮细胞凋亡的各项指标与细胞活力相关。亚毫摩尔H2O2对细胞的氧化损伤可导致50%的细胞死亡。丙酮酸可抑制H2O2诱导的大量细胞死亡，而l -乳酸和氨基乙酸则不能，这表明胞质内NADH还原当量可能通过刺激氧化剂生成而起作用。H2O2对p53的诱导和核易位被丙酮酸阻断，而与氧化剂产生相关的l -乳酸或氨基乙酸似乎在一定程度上增强。p53的核易位伴随着bax的反激活和bcl-2的下调。丙酮酸相关的氧化还原处理抑制h2o2诱导的p53激活，恢复下调的bcl-2和上调的bax，从而提高bcl-2/bax的表达比。相比之下，l -乳酸、醋酸盐或氨基乙酸盐没有这种影响。这些结果表明丙酮酸可以调节细胞质和线粒体基质中的关键调控信号通路，从而使内皮细胞死亡通路失活。此外，通过代谢抗氧化剂稳定bcl-2和bax基因的表达可能是内皮细胞抵抗氧化应激的有效策略。(C) 2003 Elsevier Inc.版权所有。
We have recently demonstrated that the redox reactant pyruvate prevents hydrogen peroxide (H2O2)-induced endothelial apoptosis and that its anti-apoptotic feature is mediated partially through the mitochondrial compartment. However, little is known about molecular signal pathways that mediate the anti-apoptotic feature of pyruvate. A biochemical approach to elucidate such signal pathways was attempted in human umbilical vein endothelial cells (HUVECs). Effects of antioxidant pyruvate were compared with those of cytosolic reductant L-lactate, redox-neutral acetate, and malate-aspartate shuttle blocker aminooxyacetate. Various indices of endothelial apoptosis were correlated with cell viability. Submillimolar H2O2 caused > 50% cell killing, as manifested by its oxidant insult. The massive cell death induced by H2O2 was inhibited by pyruvate but not by L-lactate or aminooxyacetate, suggesting a role of cytosolic NADH reducing equivalents, possibly via stimulated oxidant generation. The induction and nuclear translocation of p53 by H2O2, was blocked by pyruvate and appeared to be somewhat enhanced by L-lactate or aminooxyacetate in association with oxidant generation. Nuclear translocation of p53 accompanied the transactivation of bax and downregulation of bcl-2. The pyruvate-related redox manipulation inhibited the H2O2-induced p53 activation, restored the downregulated bcl-2 and the upregulated bax, and hence enhanced the bcl-2/bax expression ratio. In contrast, L-lactate, acetate, or aminooxyacetate had no such effect. These results indicate that pyruvate could modulate key regulatory signal pathways in cytosol and mitochondrial matrix, thereby inactivating endothelial death pathways. Furthermore, it is suggested that stabilizing the expression of bcl-2 and bax genes by metabolic antioxidants may be an effective strategy for endothelial protection against oxidative stress. (C) 2003 Elsevier Inc. All rights reserved.