Mechanism underlying oxidative stress-mediated lipotoxicity: Exposure of J774.2 macrophages to triacylglycerols facilitates mitochondrial reactive oxygen species production and cellular necrosis
Mechanism underlying oxidative stress-mediated lipotoxicity: Exposure of J774.2 macrophages to triacylglycerols facilitates mitochondrial reactive oxygen species production and cellular necrosis
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DOI：
10.1016/j.freeradbiomed.2005.01.015
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发表时间：
2005-05-01
影响因子：
7.4
通讯作者：
Tirosh, O
中科院分区：
文献类型：
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作者：
Aronis, A;Madar, Z;Tirosh, O
本研究的目的是阐明暴露于三酰甘油（TG），可能与动脉粥样硬化的发展有关的机制，导致macropliages死亡途径。将市售TG乳剂（脂质乳剂，LE; 0.1-1.5 mg脂质/ml）加入培养的J774.2细胞中。在TG处理后的第一个24小时内，细胞活性氧（ROS）水平显著升高，基础caspase-3活性减弱。相反，在48小时后，ROS的产生被阻止。TG介导的ROS产生被证明是通过电子传递链的线粒体复合物I，因为复合物1的抑制剂roterione显著减弱TG处理的细胞中的细胞ROS水平。TG效应在细胞死亡中达到顶峰，没有半胱天冬酶-3活化。因此，我们评估了TG对表现出高半胱天冬酶活性的凋亡细胞的影响。TG诱导升高的ROS水平和抑制caspase-3的凋亡细胞预处理24小时放线菌酮。碘化丙啶和Annexin V双染色后流式细胞仪分析显示TG促进细胞死亡，具有明显的坏死特征。为了阐明坏死细胞死亡过程是否确实是氧化依赖性的，研究了抗氧化保护。用N-乙酰半胱氨酸（NAC）（0.5 mM）、抗坏血酸（0.5 mM）和白藜芦醇（0.2 mM）处理可防止TG脂毒性作用，而令人惊讶的是，亲脂性抗氧化剂不能。NAC，抗坏血酸和白藜芦醇的组合，每种都在低得多的浓度下，具有协同保护作用。总之，我们在这里首次表明，暴露于TG可以通过诱导线粒体介导的长期氧化应激直接调节巨噬细胞的脂毒性;这反过来又可以抑制凋亡半胱天冬酶系统，导致坏死性细胞死亡，这可以通过特定的抗氧化剂来预防。(c)2005年爱思唯尔公司All rights reserved.
The aim of this study was to elucidate death pathways in macropliages resulting from exposure to triacylglycerols (TG), mechanisms which may be relevant to the development of atherosclerosis. A commercial TG emulsion (lipid emulsion, LE; 0.1-1.5 mg lipids/ml) was added to J774.2 cells in culture. Within the first 24 h after TG treatment, cellular reactive oxygen species (ROS) levels were strongly elevated and basal caspase-3 activity was attenuated. In contrast, after 48 h, ROS production was arrested. TG-mediated ROS production was demonstrated to be via mitochondrial complex I of the electron-transfer chain since the inhibitor of complex 1 roterione significantly attenuated the cellular ROS levels in TG-treated cells. The TG effect culminated in cell death, with no caspase-3 activation. We therefore evaluated the effect of TG on apoptotic cells showing high caspase activity. TG induced elevated ROS levels and suppressed caspase-3 in apoptotic cells pretreated for 24 h with cycloheximide. Dual staining with propidium iodide and Annexin V followed by flow cytometric analysis showed that TG facilitated cell death with clear necrotic characteristics. To elucidate whether the necrotic cell death process is indeed oxidant dependent, antioxidant protection was Studied. Treatment with N-acetylcysteine (NAC) (0.5 mM), ascorbic acid (0.5 mM), and resveratrol (0.2 mM) protected against the TG lipotoxic effect, while, surprisingly, lipophilic antioxidants did not. The combination of NAC, ascorbic acid, and resveratrol, each at much lower concentrations, had a synergistic protective effect. In conclusion, we show here for the first time that exposure to TG can directly regulate lipotoxicity in macrophages by inducing rnitochondria-mediated prolonged oxidative stress; this, in turn, can inactivate the apoptotic caspase system, resulting in necrotic cell death which can be prevented by specific antioxidants. (c) 2005 Elsevier Inc. All rights reserved.