Crosstalk between transforming growth factor-β1 and endoplasmic reticulum stress regulates alpha-smooth muscle cell actin expression in podocytes
Crosstalk between transforming growth factor-β1 and endoplasmic reticulum stress regulates alpha-smooth muscle cell actin expression in podocytes
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DOI：
10.1016/j.lfs.2018.07.050
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发表时间：
2018-09-15
期刊：
影响因子：
6.1
通讯作者：
Yang, Yu-Lin
中科院分区：
文献类型：
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作者：
Chen, Chien-An;Chang, Jer-Ming;Yang, Yu-Lin
目的：转化生长因子- β 1 （tgf - β 1）在上皮-间质转化（EMT）中起重要作用。此外，内质网应激也可诱发EMT。然而，足细胞中tgf - β 1、内质网应激和EMT之间的关系尚不清楚。因此，本研究探讨了tgf - β 1和内质网应激对EMT调控的串扰效应。主要方法：采用实时荧光定量PCR法检测EMT标志物（α -平滑肌肌动蛋白：α - sma） mRNA表达。此外，Western blot检测α - sma蛋白和3个内质网应激生物标志物（葡萄糖调节蛋白78:GRP78；真核翻译起始因子2 α: eIF2 α； CCAAT/增强子结合蛋白同源蛋白：CHOP）的表达。关键发现：tgf - β 1增加内质网应激反应生物标志物（GRP78、p-eIF2 α /eIF2 α和CHOP）和足细胞α - sma mRNA和蛋白水平。此外，内质网应激诱导剂（thapsigargin）增加了α - sma蛋白的表达。内质网应激抑制剂（4-苯基丁酸酯）在tgf - β 1处理下减弱内质网应激反应和α - sma蛋白表达。在本研究考虑的多种tgf - β 1下游通路抑制剂（SIS3: Smad2/3抑制剂；U0126: MEK/ERK抑制剂；SB203580: p38抑制剂）中，SIS3在tgf - β 1治疗下显著减弱内质网应激反应生物标志物（GRP78）。在tgf - β 1处理下，SIS3、U0126和SB203580均部分减弱α - sma mRNA的表达。然而，只有SIS3能减弱α - sma蛋白的表达。意义：本研究结果证实内质网应激诱导足细胞α - sma蛋白表达。此外，tgf - β 1主要通过Smad2/3通路调节内质网应激和α - sma蛋白表达。因此，内质网应激和tgf - β 1可能协同诱导足细胞进行EMT。
Aims: Transforming growth factor-beta 1 (TGF-beta 1) plays a significant role in epithelial-mesenchymal transition (EMT). Furthermore, endoplasmic reticulum (ER) stress also can induce EMT. However, the relationship among TGF-beta 1, ER stress and EMT in podocytes is still unclear. Consequently, this study examines the crosstalk effect between TGF-beta 1 and ER stress on the regulation of EMT.Main methods: The mRNA of EMT marker (alpha-smooth muscle actin: alpha-SMA) was evaluated by quantitative real-time PCR. In addition, the protein expressions of alpha-SMA and three ER stress biomarkers (glucose-regulated protein 78: GRP78; eukaryotic translation initiation factor 2 alpha: eIF2 alpha; CCAAT/enhancer-binding proteinhomologous protein: CHOP) were evaluated by Western blot.Key findings: TGF-beta 1 increased the ER stress response biomarkers (GRP78, p-eIF2 alpha/eIF2 alpha and CHOP) and mRNA and protein levels of alpha-SMA in podocytes. Furthermore, ER stress inducer (thapsigargin) increased alpha-SMA protein expression. ER stress inhibitor (4-phenylbutyrate) attenuated the ER stress response and alpha-SMA protein expression under treatment with TGF-beta 1. Among the various TGF-beta 1 down-stream pathway inhibitors considered in the present study (SIS3: inhibitor of Smad2/3; U0126: inhibitor of MEK/ERK; SB203580: inhibitor of p38), SIS3 greatly attenuated the ER stress response biomarker (GRP78) under treatment with TGF-beta 1. SIS3, U0126 and SB203580 all partly attenuated alpha-SMA mRNA expression under TGF-beta 1 treatment. However, only SIS3 attenuated alpha-SMA protein expression.Significance: The present results confirm that ER stress induces alpha-SMA protein expression in podocytes. Furthermore, TGF-beta 1 mainly regulates ER stress and alpha-SMA protein expression through the Smad2/3 pathway. Therefore, ER stress and TGF-beta 1 may synergistically induce podocytes to undergo EMT.