Department of Nephrology, Affiliated Beijing Friendship Hospital, Faculty of Kidney Diseases, Capital Medical University, Beijing 100050, China.
Acta Biochim Biophys Sin (Shanghai). 2012 Nov;44(11):918-23. doi: 10.1093/abbs/gms077. Epub 2012 Sep 30.
Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is considered to be an independent risk factor in the progression of chronic kidney diseases (CKD). It can induce kidney fibrosis by increasing transforming growth factor (TGF)-β1 expression, but its molecular mechanism is unclear. The aim of the present study was to investigate the role of actin cytoskeleton in ADMA-induced TGF-β1 high expression in human renal glomerular endothelial cells (HRGECs). The structure of stress fibers was visualized by immunofluorescence, nuclear factor-κB (NF-κB) DNA-binding activity was assessed by an electrophoretic mobility shift assay and TGF-β1 expression was assessed by western blot analysis. Results showed that ADMA induced the assembly of stress fibers, DNA binding of NF-κB, and increasing expression of TGF-β1. When the dynamics of actin cytoskeleton was perturbed by the actin-depolymerizing agent cytochalasin D and the actin-stabilizing agent jasplakinolide, or ablation of stress fiber bundles by the nicotineamide adenine dinucleotide phosphate oxidase inhibitor apocynin and p38 mitogen-activated protein kinase inhibitor SB203580, ADMA-induced DNA binding of NF-κB and TGF-β1 expression were inhibited. These results revealed an actin cytoskeleton-dependent mechanism in ADMA-induced NF-κB activation and TGF-β1 high expression in HRGECs. The specific targeting of the actin cytoskeleton may be a useful strategy to prevent ADMA-activated kidney fibrosis in CKD.
不对称二甲基精氨酸（ADMA），一种内源性一氧化氮合酶抑制剂，被认为是慢性肾脏病（CKD）进展的独立危险因素。它可以通过增加转化生长因子（TGF）-β1 的表达来诱导肾脏纤维化，但它的分子机制尚不清楚。本研究旨在探讨细胞骨架肌动蛋白在 ADMA 诱导的人肾小球内皮细胞（HRGECs）中 TGF-β1 高表达中的作用。通过免疫荧光法观察应力纤维的结构，通过电泳迁移率变动分析评估核因子-κB（NF-κB）DNA 结合活性，通过 Western blot 分析评估 TGF-β1 的表达。结果表明，ADMA 诱导应力纤维的组装、NF-κB 的 DNA 结合和 TGF-β1 的表达增加。当肌动蛋白细胞骨架的动力学被肌动蛋白解聚剂细胞松弛素 D 和肌动蛋白稳定剂 jasplakinolide 扰乱，或通过烟酰胺腺嘌呤二核苷酸磷酸氧化酶抑制剂 apocynin 和 p38 丝裂原活化蛋白激酶抑制剂 SB203580 消融应力纤维束时，ADMA 诱导的 NF-κB 的 DNA 结合和 TGF-β1 的表达受到抑制。这些结果揭示了细胞骨架肌动蛋白在 ADMA 诱导的 NF-κB 激活和 HRGECs 中 TGF-β1 高表达中的作用机制。细胞骨架肌动蛋白的特异性靶向可能是预防 CKD 中 ADMA 激活的肾脏纤维化的一种有用策略。
