Department of Pharmacology, Toxicology, and Neuroscience, LSU Health Sciences Center in Shreveport, Shreveport, Louisiana 71130, USA.
Toxicol Sci. 2013 Aug;134(2):323-34. doi: 10.1093/toxsci/kft105. Epub 2013 May 2.
Cardiovascular complications have been documented in HIV-1 infected populations, and antiretroviral therapy may play a role. Nucleoside reverse transcriptase inhibitors (NRTIs) are antiretrovirals known to induce mitochondrial damage in endothelial cells, culminating in endothelial dysfunction, an initiating event in atherogenesis. Though the mechanism for NRTI-induced endothelial toxicity is not yet clear, our prior work suggested that a mitochondrial oxidative stress may be involved. To further delineate the mechanism of toxicity, endothelial cells were treated with NRTIs of varying subclasses, and the level of reactive oxygen species (ROS) and mitochondrial function were assessed. To test whether rescue of mitochondrial electron transport attenuated NRTI-induced endothelial cytotoxicity, in some cases, cells were cotreated with the electron transport cofactor coenzyme Q10 (Q10). At 4-6h, NRTIs increased levels of ROS but decreased the activities of electron transport chain complexes I-IV, levels of ATP and the NAD/NADH ratio. Moreover, nitric oxide levels were decreased, whereas endothelin-1 release was increased. Q10 abolished NRTI-induced mitochondria injury and effects on endothelial agonist production. Interestingly, in cells treated with NRTIs only, markers for mitochondrial toxicity returned to baseline levels by 18-24h, suggesting a compensatory mechanism for clearing damaged mitochondria. Using confocal microscopy, with confirmation utilizing the autophagy and mitophagy markers LC-3 and Nix, respectively, we observed autophagy of mitochondria at 8-10h after treatment. Q10 prevented NRTI-mediated increase in LC-3. These findings suggest that NRTI-induced mitophagy may be involved in NRTI-induced endothelial dysfunction and that this damage likely results from oxidant injury. Further, Q10 supplementation could potentially prevent NRTI-induced endothelial dysfunction.
心血管并发症已在 HIV-1 感染人群中得到证实，而抗逆转录病毒疗法可能在此过程中发挥作用。核苷类逆转录酶抑制剂（NRTIs）是已知可导致内皮细胞线粒体损伤的抗逆转录病毒药物，最终导致内皮功能障碍，这是动脉粥样硬化形成的起始事件。尽管 NRTI 诱导内皮毒性的机制尚不清楚，但我们之前的工作表明，线粒体氧化应激可能与此有关。为了进一步阐明毒性机制，我们用不同亚类的 NRTI 处理内皮细胞，评估活性氧（ROS）水平和线粒体功能。为了测试电子传递辅助因子辅酶 Q10（Q10）是否可以挽救线粒体电子传递来减轻 NRTI 诱导的内皮细胞毒性，在某些情况下，细胞被共同用 Q10 处理。在 4-6 小时时，NRTI 增加了 ROS 水平，但降低了电子传递链复合物 I-IV、ATP 水平和 NAD/NADH 比值的活性。此外，一氧化氮水平下降，而内皮素-1 的释放增加。Q10 消除了 NRTI 诱导的线粒体损伤和对内皮激动剂产生的影响。有趣的是，在仅用 NRTI 处理的细胞中，线粒体毒性标志物在 18-24 小时后恢复到基线水平，这表明存在一种清除受损线粒体的补偿机制。通过共聚焦显微镜观察，分别用自噬和线粒体自噬标志物 LC-3 和 Nix 进行确认，我们观察到在处理后 8-10 小时线粒体自噬。Q10 可预防 NRTI 介导的 LC-3 增加。这些发现表明，NRTI 诱导的线粒体自噬可能与 NRTI 诱导的内皮功能障碍有关，而这种损伤可能是由氧化应激引起的。此外，Q10 补充剂可能潜在地预防 NRTI 诱导的内皮功能障碍。
