Área de Farmacología y Toxicología, Departamento de Farmacia, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina.
Cell Stress Chaperones. 2011 Jan;16(1):57-68. doi: 10.1007/s12192-010-0221-y. Epub 2010 Aug 24.
Perturbation of renal tubular antioxidants and overproduction of reactive oxygen species may amplify the proinflammatory state of renal obstruction, culminating in oxidative stress and tubular loss. Here, we analyzed the heat shock protein 70 (Hsp70) response and the function and signal transduction of NF-E2-related protein 2 (Nrf2) transcription factor on oxidative stress modulation in obstruction. Rats were subjected to unilateral ureteral obstruction or sham operation and kidneys harvested at 5, 7, 10, and 14 days after obstruction. Hsp70 expression and Nrf2 activity and its downstream target gene products were assessed. After 10 and 14 days of obstruction, enhanced lipid peroxidation through higher thiobarbituric acid reactive substances levels and increased oxidative stress resulted in reduced total antioxidant activity and enhanced nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase activity were demonstrated. This was accompanied by decreased inducible Hsp70 expression and a progressive reduction of nuclear Nrf2 and its target gene products glutathione S-transferase A2 (GSTA2) and NADPH/quinone oxidoreductase 1 (NQO1), whereas the Nrf2 repressor Kelch-like ECH-associated protein-1 (Keap1) was upregulated. By contrast, on early obstruction for 7 days, lack of increased oxidative markers associated with higher inducible Hsp70 protein levels and a rapid nuclear accumulation of Nrf2, Keap1 downregulation, and mRNA induction of the identified Nrf2-dependent genes, NQO1 and GSTA2, were shown. For these results, we suggest that the magnitude of cytoprotection in early obstruction depends on the combined contribution of induced activation of Nrf2 upregulating its downstream gene products and Hsp70 response. Impaired ability to mount the biological response to the prevailing oxidative stress leading to renal injury was shown in prolonged obstruction.
肾近端小管抗氧化剂的破坏和活性氧的过度产生可能会放大肾梗阻的促炎状态，最终导致氧化应激和小管丢失。在这里，我们分析了热休克蛋白 70（Hsp70）反应以及核因子 E2 相关蛋白 2（Nrf2）转录因子在梗阻氧化应激调节中的功能和信号转导。大鼠接受单侧输尿管梗阻或假手术，并在梗阻后 5、7、10 和 14 天采集肾脏。评估 Hsp70 表达和 Nrf2 活性及其下游靶基因产物。在梗阻 10 和 14 天后，通过更高的硫代巴比妥酸反应物质水平增强脂质过氧化作用，导致总抗氧化活性降低，烟酰胺腺嘌呤二核苷酸磷酸还原酶（NADPH）氧化酶活性增强。这伴随着诱导型 Hsp70 表达减少，核 Nrf2 及其靶基因产物谷胱甘肽 S-转移酶 A2（GSTA2）和 NADPH/醌氧化还原酶 1（NQO1）逐渐减少，而 Nrf2 抑制剂 Kelch 样 ECH 相关蛋白-1（Keap1）上调。相比之下，在早期梗阻的 7 天内，缺乏与较高的诱导型 Hsp70 蛋白水平相关的增加的氧化标志物，以及 Nrf2 的快速核积累、Keap1 下调和鉴定的 Nrf2 依赖性基因（NQO1 和 GSTA2）的 mRNA 诱导表明。对于这些结果，我们认为早期梗阻中细胞保护的程度取决于 Nrf2 诱导激活及其下游基因产物上调的综合贡献和 Hsp70 反应。在延长的梗阻中，显示出对占主导地位的氧化应激产生生物反应的能力受损，导致肾损伤。
