Xiao Zhicheng, Zhang Jing, Peng Xiaogang, Dong Yanjun, Jia Lixin, Li Huihua, Du Jie
Beijing AnZhen Hospital, Capital Medical University, The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Ministry of Education, Beijing, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing, China.
Department of Physiology and Pathophysiology, Capital Medical University, Beijing, China.
Int J Biochem Cell Biol. 2014 Oct;55:65-71. doi: 10.1016/j.biocel.2014.08.009. Epub 2014 Aug 20.
Kidney fibrosis is a common feature of chronic kidney disease (CKD). A recent study suggests that abnormal Notch signaling activation contributes to the development of renal fibrosis. However, the molecular mechanism that regulates this process remains unexplored. Unilateral ureteral obstruction (UUO) or sham-operated C57BL6 mice (aged 10 weeks) were randomly assigned to receive dibenzazepine (DBZ, 250 μg/100g/d) or vehicle for 7 days. Histologic examinations were performed on the kidneys using Masson's trichrome staining and immunohistochemistry. Real-time PCR and western blot analysis were used for detection of mRNA expression and protein phosphorylation. The expression of Notch 1, 3, and 4, Notch intracellular domain (NICD), and its target genes Hes1 and HeyL were upregulated in UUO mice, while the increase in NICD protein was significantly attenuated by DBZ. After 7 days, the severity of renal fibrosis and expression of fibrotic markers, including collagen 1α1/3α1, fibronectin, and α-smooth muscle actin, were markedly increased in UUO compared with sham mice. In contrast, administration of DBZ markedly attenuated these effects. Furthermore, DBZ significantly inhibited UUO-induced expression of transforming growth factor (TGF)-β, phosphorylated Smad 2, and Smad 3. Mechanistically, Notch signaling activation in tubular epithelial cells enhanced fibroblast proliferation and activation in a coculture experiment. Our study provides evidence that Notch signaling is implicated in renal fibrogenesis. The Notch inhibitor DBZ can ameliorate this process via inhibition of the TGF-β/Smad2/3 signaling pathway, and might be a novel drug for preventing chronic kidney disease.
肾纤维化是慢性肾脏病（CKD）的常见特征。最近一项研究表明，Notch信号通路异常激活促进肾纤维化的发展。然而，调节这一过程的分子机制仍未被探索。将单侧输尿管梗阻（UUO）或假手术的C57BL6小鼠（10周龄）随机分为两组，分别接受二苯氮䓬（DBZ，250μg/100g/天）或溶剂处理7天。使用Masson三色染色和免疫组织化学对肾脏进行组织学检查。采用实时PCR和蛋白质印迹分析检测mRNA表达和蛋白质磷酸化。UUO小鼠中Notch 1、3和4、Notch细胞内结构域（NICD）及其靶基因Hes1和HeyL的表达上调，而DBZ可显著减弱NICD蛋白的增加。7天后，与假手术小鼠相比，UUO小鼠肾纤维化的严重程度以及包括胶原蛋白1α1/3α1、纤连蛋白和α平滑肌肌动蛋白在内的纤维化标志物的表达明显增加。相比之下，给予DBZ可显著减弱这些作用。此外，DBZ显著抑制UUO诱导的转化生长因子（TGF）-β、磷酸化Smad 2和Smad 3的表达。从机制上讲，在共培养实验中，肾小管上皮细胞中的Notch信号通路激活增强了成纤维细胞的增殖和活化。我们的研究提供了证据表明Notch信号通路与肾纤维化形成有关。Notch抑制剂DBZ可通过抑制TGF-β/Smad2/3信号通路改善这一过程，可能是一种预防慢性肾脏病的新型药物。
