miR-21 overexpression enhances TGF-β1-induced epithelial-to-mesenchymal transition by target smad7 and aggravates renal damage in diabetic nephropathy
miR-21 overexpression enhances TGF-β1-induced epithelial-to-mesenchymal transition by target smad7 and aggravates renal damage in diabetic nephropathy
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DOI：
10.1016/j.mce.2014.05.018
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发表时间：
2014-07-05
影响因子：
4.1
通讯作者：
Yang, Jin-Kui
中科院分区：
文献类型：
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作者：
Wang, Jin-Yang;Gao, Yan-Bin;Yang, Jin-Kui
上皮细胞向间质细胞转化（EMT）在糖尿病肾病（ON）肾间质纤维化（RIF）中发挥重要作用。Smad 7是TGF-β 1的下游信号分子，抑制EMT的发生。miR-21的生理功能与EMT和RIF密切相关。然而，目前尚不清楚miR-21过表达是否通过调节smad 7影响TGF-β 1诱导的DN EMT。本研究分别采用实时荧光定量RT-PCR、细胞转染、荧光素酶报告基因检测、蛋白质印迹和共聚焦显微镜等技术。在此，我们发现TGF-β 1以时间和浓度依赖性方式上调miR-21表达。此外，miR-21过表达可通过直接下调smad 7/p-smad 7和间接上调smad 3/p-smad 3，增强TGF-β 1诱导的EMT（上调a-SMA和下调E-cadherin），并伴有Ccr降低，col-IV、FN、胶原纤维含量、RTBM、RTIAW和ACR增加。同时，siRNA实验表明smad 7可以直接调控a-SMA和E-cadherin的表达。更重要的是，miR-21抑制剂不仅可以抑制EMT和纤维化，还可以改善肾脏结构和功能。总之，我们的研究结果表明，miR-21过表达可以通过抑制靶点smad 7而促进TGF-β 1诱导的EMT，并且靶向miR-21可能是直接抑制TGF-β 1介导的DN纤维化的更好的替代方案。(C)2014爱思唯尔爱尔兰有限公司版权所有。
Epithelial-to-mesenchymal transition (EMT) plays an important role in renal interstitial fibrosis (RIF) with diabetic nephropathy (ON). Smad7 (a inhibitory smad), a downstream signaling molecules of TGF-beta 1, represses the EMT. The physiological function of miR-21 is closely linked to EMT and RIF. However, it remained unclear whether miR-21 over-expression affected TGF-beta 1 -induced EMT by regulating smad7 in DN. In this study, real-time RT-PCR, cell transfection, luciferase reporter gene assays, western blot and confocal microscope were used, respectively. Here, we found that miR-21 expression was upregulated by TGF-beta 1 in time- and concentration -dependent manner. Moreover, miR-21 over-expression enhanced TGF-beta 1-induced EMT(upregulation of a-SMA and downregulation of E-cadherin) by directly down-regulating smad7/p-smad7 and indirectly up-regulating smad3/p-smad3, accompanied by the decrease of Ccr and the increase of col-IV, FN, the content of collagen fibers, RTBM, RTIAW and ACR. Meantime, the siRNA experiment showed that smad7 can directly regulate a-SMA and E-cadherin expression. More importantly, miR-21 inhibitor can not only inhibit EMT and fibrosis but also ameliorate renal structure and function. In conclusion, our results demonstrated that miR-21 overexpression can contribute to TGF-beta 1 -induced EMT by inhibiting target smad7, and that targeting miR-21 may be a better alternative to directly suppress TGF-beta 1-mediated fibrosis in DN. (C) 2014 Elsevier Ireland Ltd. All rights reserved.