Ubiquitin-dependent degradation of SnoN and Ski is increased in renal fibrosis induced by obstructive injury
Ubiquitin-dependent degradation of SnoN and Ski is increased in renal fibrosis induced by obstructive injury
复制标题
DOI：
10.1038/sj.ki.5000261
复制
发表时间：
2006-05-01
影响因子：
19.6
通讯作者：
Hishida, A.
中科院分区：
文献类型：
--
作者：
Fukasawa, H.;Yamamoto, T.;Hishida, A.
转化生长因子-β（TGF-β）在肾纤维化的进展中发挥着关键作用。 TGF-β的活性受到多种机制的严格控制，其中通过共阻遏物拮抗Smad介导的基因转录是重要的组成部分之一。我们研究了肾纤维化过程中 Smad 转录辅阻遏物 SnoN（滑雪相关新基因 N）和 Ski（斯隆-凯特琳研究所原癌基因）的表达、降解和泛素化。我们还研究了 Smad 泛素化调节因子 2 (Smurf2) 在 SnoN 蛋白泛素化中的参与。使用单侧输尿管梗阻（UUO）小鼠和假手术小鼠的肾脏。通过免疫组织化学、蛋白质印迹和/或实时逆转录聚合酶链反应检查肾脏病变和 TGF-β1、I 型胶原、SnoN、Ski 和 Smurf2 的表达。还研究了 SnoN/Ski 蛋白的降解和泛素化。 UUO小鼠的梗阻肾脏表现出进行性肾小管间质纤维化，TGF-β1、I型胶原、SnoN和Ski mRNA的高表达水平，以及SnoN和Ski蛋白的低水平表达。梗阻肾脏中 SnoN/Ski 蛋白的降解和泛素化均显着增加，其中 Smurf2 表达增加。梗阻肾脏提取物中的 Smurf2 免疫耗竭导致 SnoN 泛素化减少。我们的结果表明，泛素依赖性降解增加导致 SnoN/Ski 蛋白的减少与肾小管间质纤维化的进展有关。
Transforming growth factor-beta ( TGF-beta) plays a critical role in the progression of renal fibrosis. The activity of TGF-beta is tightly controlled by various mechanisms, among which antagonizing Smad-mediated gene transcription by co-repressors represents one of the important components. We investigated the expression, degradation, and ubiquitination of Smad transcriptional co-repressors SnoN ( ski-related novel gene N) and Ski ( Sloan-Kettering Institute proto-oncogene) in renal fibrogenesis. We also studied the involvement of Smad-ubiquitination regulatory factor 2 ( Smurf2) in ubiquitination of SnoN protein. The kidneys of mice with unilateral ureteral obstruction ( UUO) and those of sham-operated mice were used. Renal lesions and the expression of TGF-beta 1, type I collagen, SnoN, Ski, and Smurf2 were examined by immunohistochemistry, Western blot, and/or real-time reverse transcriptase-polymerase chain reaction. Degradation and ubiquitination of SnoN/Ski proteins were also investigated. The obstructed kidneys of UUO mice showed progressive tubulointerstitial fibrosis, high expression levels of TGF-beta 1, type I collagen, SnoN and Ski mRNAs, and low levels of SnoN and Ski proteins. Both degradation and ubiquitination of SnoN/Ski proteins were markedly increased in the obstructed kidneys, in which Smurf2 expression was increased. Smurf2 immunodepletion in extracts of obstructed kidneys resulted in reduced ubiquitination of SnoN. Our results suggest that the reduction of SnoN/Ski proteins resulting from increased ubiquitin-dependent degradation is involved in the progression of tubulointerstitial fibrosis.