A Novel Small Compound That Promotes Nuclear Translocation of YB-1 Ameliorates Experimental Hepatic Fibrosis in Mice
A Novel Small Compound That Promotes Nuclear Translocation of YB-1 Ameliorates Experimental Hepatic Fibrosis in Mice
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DOI：
10.1074/jbc.m110.151936
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发表时间：
2011-02-01
影响因子：
4.8
通讯作者：
Kaneko, Hideo
中科院分区：
文献类型：
--
作者：
Higashi, Kiyoshi;Tomigahara, Yoshitaka;Kaneko, Hideo
转化生长因子-β（TGF-β）被认为是导致肝纤维化的主要因素。我们之前已经证明，YB-1 的核转位在调节胶原蛋白基因表达中拮抗 TGF-β/Smad3 信号传导。最近，我们证明新型小化合物HSc025可促进YB-1的核转位，从而改善皮肤和肺纤维化。在这里，我们提供了关于 HSc025 刺激 YB-1 核转位的机制以及 HSc025 对小鼠肝纤维化模型的药理作用的证据。使用 HSc025 固定树脂的蛋白质组学方法和结合测定表明，HSc025 与 YB-1 C 尾区域内的氨基酸序列结合。此外，免疫沉淀实验和谷胱甘肽 S-转移酶 Pulldown 测定确定多聚腺苷酸结合蛋白 (PABP) 是 YB-1 的细胞质锚定蛋白之一。 HSc025 直接与 YB-1 结合并中断其与 PABP 的相互作用，导致 YB-1 的核易位加速。用 PABP siRNA 转染细胞促进 YB-1 的核转位，随后抑制基础和 TGF-β 刺激的胶原蛋白基因表达。此外，HSc025 显着抑制培养的活化肝星状细胞中胶原蛋白基因的表达。对四氯化碳诱导的肝纤维化小鼠口服HSc025可改善肝损伤以及肝纤维化的程度。总而言之，这些结果为使用 YB-1 调节剂治疗器官纤维化提供了新的见解。
Transforming growth factor-beta (TGF-beta) is considered to be a major factor contributing to liver fibrosis. We have previously shown that nuclear translocation of YB-1 antagonizes the TGF-beta/Smad3 signaling in regulating collagen gene expression. More recently, we have demonstrated that the novel small compound HSc025 promotes nuclear translocation of YB-1, resulting in the improvement of skin and pulmonary fibrosis. Here, we presented evidence as to the mechanism by which HSc025 stimulates nuclear translocation of YB-1 and the pharmacological effects of HSc025 on a murine model of hepatic fibrosis. A proteomics approach and binding assays using HSc025-immobilized resin showed that HSc025 binds to the amino acid sequence within the C-tail region of YB-1. In addition, immunoprecipitation experiments and glutathione S-transferase pulldown assays identified poly(A)-binding protein (PABP) as one of the cytoplasmic anchor proteins of YB-1. HSc025 directly binds to YB-1 and interrupts its interaction with PABP, resulting in accelerated nuclear translocation of YB-1. Transfection of cells with PABP siRNA promoted nuclear translocation of YB-1 and subsequently inhibited basal and TGF-beta-stimulated collagen gene expression. Moreover, HSc025 significantly suppressed collagen gene expression in cultured activated hepatic stellate cells. Oral administration of HSc025 to mice with carbon tetrachloride-induced hepatic fibrosis improved liver injury as well as the degree of hepatic fibrosis. Altogether, the results provide a novel insight into therapy for organ fibrosis using YB-1 modulators.