Department of Pathology and Key Laboratory of Molecular Medicine, School of Basic Medical Sciences, Fudan University, Shanghai, People's Republic of China.
Cell Signal. 2013 Jul;25(7):1574-85. doi: 10.1016/j.cellsig.2013.03.018. Epub 2013 Apr 6.
In kidney, the ubiquitin carboxy-terminal hydrolase 1 (UCH-L1) is involved in podocyte injury and proteinuria but details of the mechanism underlying its regulation are not known. Activation of NF-κB is thought to be the predominant risk factor for kidney disease; therefore, it is postulated that UCH-L1 may be one of the NF-κB target genes. In this study, we investigated the involvement of NF-κB activation in the regulation of UCH-L1 expression and the function of murine podocytes. Stimulation of podocytes with the cytokines TNF-α and IL-1β up-regulated UCH-L1 expression rapidly at the mRNA and protein levels and the NF-κB-specific inhibitor pyrrolidine dithiocarbamate resulted in down-regulation. NF-κB up-regulates UCH-L1 via binding the --300 bp and --109 bp sites of its promoter, which was confirmed by the electrophoretic mobility shift assay of DNA-nuclear protein binding. In the renal biopsy from lupus nephritis patients, the expressions of NF-κB and UCH-L1 increased in immunohistochestry staining and were positively correlated. Activation of NF-κB up-regulates UCH-L1 expression following changing of other podocytes molecules, such as nephrin and snail. These results suggest that activation of the NF-κB signaling pathway could be the major pathogenesis to up-regulate UCH-L1 in podocyte injury, followed by the turnover of other molecules, which might result in morphological changes and dysfunction of podocytes. This work help us to understand the effect of NF-κB on specific target molecules of podocytes, and suggest that targeting the NF-κB-UCH-L1 interaction could be a novel therapeutic strategy for the treatment of podocyte lesions and proteinuria.
在肾脏中，泛素羧基末端水解酶 1（UCH-L1）参与足细胞损伤和蛋白尿，但调节其机制的细节尚不清楚。NF-κB 的激活被认为是肾脏疾病的主要危险因素；因此，假设 UCH-L1 可能是 NF-κB 靶基因之一。在这项研究中，我们研究了 NF-κB 激活在 UCH-L1 表达调节和鼠足细胞功能中的作用。细胞因子 TNF-α 和 IL-1β 刺激足细胞可迅速上调 UCH-L1 的 mRNA 和蛋白水平，NF-κB 特异性抑制剂吡咯烷二硫代氨基甲酸盐可下调 UCH-L1 的表达。NF-κB 通过结合其启动子的 --300 bp 和 --109 bp 位点上调 UCH-L1 的表达，这通过 DNA-核蛋白结合的电泳迁移率变动分析得到证实。在狼疮肾炎患者的肾活检中，NF-κB 和 UCH-L1 的表达在免疫组织化学染色中增加，并且呈正相关。NF-κB 的激活上调 UCH-L1 的表达，同时改变其他足细胞分子，如nephrin 和 snail。这些结果表明，NF-κB 信号通路的激活可能是足细胞损伤上调 UCH-L1 的主要发病机制，随后是其他分子的更替，这可能导致足细胞形态变化和功能障碍。这项工作有助于我们了解 NF-κB 对足细胞特定靶分子的影响，并表明针对 NF-κB-UCH-L1 相互作用可能是治疗足细胞损伤和蛋白尿的新的治疗策略。
