Stacchiotti Alessandra, Morandini Fausta, Bettoni Francesca, Schena Ilaria, Lavazza Antonio, Grigolato Pier Giovanni, Apostoli Pietro, Rezzani Rita, Aleo Maria Francesca
Human Anatomy Unit, Department of Biomedical Sciences and Biotechnology, School of Medicine, University of Brescia, Italy.
Toxicology. 2009 Oct 29;264(3):215-24. doi: 10.1016/j.tox.2009.08.014. Epub 2009 Aug 29.
A close link between stress protein up-regulation and oxidative damage may provide a novel therapeutic tool to counteract nephrotoxicity induced by toxic metals in the human population, mainly in children, of industrialized countries. Here we analysed the time course of the expression of several heat shock proteins, glucose-regulated proteins and metallothioneins in a rat proximal tubular cell line (NRK-52E) exposed to subcytotoxic doses of inorganic mercury and lead. Concomitantly, we used morphological and biochemical methods to evaluate metal-induced cytotoxicity and oxidative damage. In particular, as biochemical indicators of oxidative stress we detected reactive oxygen species (ROS) and nitrogen species (RNS), total glutathione (GSH) and glutathione-S-transferase (GST) activity. Our results clearly demonstrated that mercury increases ROS and RNS levels and the expressions of Hsp25 and inducible Hsp72. These findings are corroborated by evident mitochondrial damage, apoptosis or necrosis. By contrast, lead is unable to up-regulate Hsp72 but enhances Grp78 and activates nuclear Hsp25 translocation. Furthermore, lead causes endoplasmic reticulum (ER) stress, vacuolation and nucleolar segregation. Lastly, both metals stimulate the over-expression of MTs, but with a different time course. In conclusion, in NRK-52E cell line the stress response is an early and metal-induced event that correlates well with the direct oxidative damage induced by mercury. Indeed, different chaperones are involved in the specific nephrotoxic mechanism of these environmental pollutants and work together for cell survival.
应激蛋白上调与氧化损伤之间的紧密联系可能为对抗工业化国家人群（主要是儿童）中有毒金属诱导的肾毒性提供一种新的治疗工具。在此，我们分析了暴露于亚细胞毒性剂量无机汞和铅的大鼠近端肾小管细胞系（NRK - 52E）中几种热休克蛋白、葡萄糖调节蛋白和金属硫蛋白的表达时间进程。同时，我们使用形态学和生化方法评估金属诱导的细胞毒性和氧化损伤。特别是，作为氧化应激的生化指标，我们检测了活性氧（ROS）和活性氮（RNS）、总谷胱甘肽（GSH）和谷胱甘肽 - S - 转移酶（GST）活性。我们的结果清楚地表明，汞会增加ROS和RNS水平以及Hsp25和诱导型Hsp72的表达。明显的线粒体损伤、凋亡或坏死证实了这些发现。相比之下，铅无法上调Hsp72，但会增强Grp78并激活核Hsp25易位。此外，铅会导致内质网（ER）应激、空泡化和核仁分离。最后，两种金属都会刺激MTs的过度表达，但时间进程不同。总之，在NRK - 52E细胞系中，应激反应是一个早期的、由金属诱导的事件，并与汞诱导的直接氧化损伤密切相关。实际上，不同的伴侣蛋白参与了这些环境污染物的特定肾毒性机制，并共同作用以维持细胞存活。
