Gaedeke Jens, Noble Nancy A, Border Wayne A
Fibrosis Research Laboratory, Division of Nephrology, University of Utah, Salt Lake City, Utah, USA.
Kidney Int. 2004 Jul;66(1):112-20. doi: 10.1111/j.1523-1755.2004.00713.x.
Over-expression of transforming growth factor-beta (TGF-beta) contributes greatly to fibrotic kidney disease. The activator protein-1 (AP-1) inhibitor curcumin, a polyphenolic compound derived from Curcuma longa, has been shown to reduce collagen accumulation in experimental pulmonary fibrosis. Here, we investigate curcumin's ability to modulate TGF-beta's profibrotic actions in vitro.
NRK49F rat renal fibroblasts were stimulated with TGF-beta (5 ng/mL), and the effects of curcumin on TGF-beta-regulated genes, TGF-beta receptors, and phosphorylated SMAD isoforms were analyzed by Northern blotting, enzyme-linked immunosorbent assay (ELISA), and Western blotting. The effects of c-jun depletion on TGF-beta-regulated gene and protein expression were analyzed with RNAi.
When applied 30 minutes before TGF-beta, curcumin dose dependently and dramatically reduced TGF-beta-induced increases in plasminogen activator inhibitor-1 (PAI-1), TGF-beta1, fibronectin (FN) and collagen I (Col I) mRNA, and in PAI-1 and fibronectin protein. Prolonged curcumin treatment (>6 h) significantly reduced TGF-beta receptor type II levels and SMAD2/3 phosphorylation in response to added TGF-beta. Depletion of cellular c-jun levels with a RNAi method mimicked the effects of curcumin on expression of TGF-beta1, FN, and Col I, but not PAI-1.
Curcumin blocks TGF-beta's profibrotic actions on renal fibroblasts through down-regulation of TbetaRII, and through partial inhibition of c-jun activity. These in vitro data suggest that curcumin might be an effective antifibrotic drug in the treatment of chronic kidney disease.
转化生长因子-β（TGF-β）的过度表达在纤维化肾病中起很大作用。激活蛋白-1（AP-1）抑制剂姜黄素是一种从姜黄中提取的多酚类化合物，已被证明可减少实验性肺纤维化中的胶原蛋白积累。在此，我们研究姜黄素在体外调节TGF-β促纤维化作用的能力。
用TGF-β（5 ng/mL）刺激NRK49F大鼠肾成纤维细胞，通过Northern印迹、酶联免疫吸附测定（ELISA）和Western印迹分析姜黄素对TGF-β调节基因、TGF-β受体和磷酸化SMAD亚型的影响。用RNA干扰分析c-jun缺失对TGF-β调节基因和蛋白表达的影响。
在TGF-β作用前30分钟应用姜黄素，可剂量依赖性且显著降低TGF-β诱导纤溶酶原激活物抑制剂-1（PAI-1）、TGF-β1、纤连蛋白（FN）和I型胶原（Col I）mRNA以及PAI-1和纤连蛋白蛋白的增加。长时间姜黄素处理（>6小时）可显著降低添加TGF-β后II型TGF-β受体水平和SMAD2/3磷酸化。用RNA干扰方法降低细胞c-jun水平可模拟姜黄素对TGF-β1、FN和Col I表达的影响，但对PAI-1无影响。
姜黄素通过下调TβRII以及部分抑制c-jun活性来阻断TGF-β对肾成纤维细胞的促纤维化作用。这些体外数据表明姜黄素可能是治疗慢性肾病的一种有效抗纤维化药物。
