scholarly journals Gremlin Activates the Smad Pathway Linked to Epithelial Mesenchymal Transdifferentiation in Cultured Tubular Epithelial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Raquel Rodrigues-Diez ◽  
Raúl R. Rodrigues-Diez ◽  
Carolina Lavoz ◽  
Gisselle Carvajal ◽  
Alejandra Droguett ◽  
...  

Gremlin is a developmental gene upregulated in human chronic kidney disease and in renal cells in response to transforming growth factor-β(TGF-β). Epithelial mesenchymal transition (EMT) is one process involved in renal fibrosis. In tubular epithelial cells we have recently described that Gremlin induces EMT and acts as a downstream TGF-βmediator. Our aim was to investigate whether Gremlin participates in EMT by the regulation of the Smad pathway. Stimulation of human tubular epithelial cells (HK2) with Gremlin caused an early activation of the Smad signaling pathway (Smad 2/3 phosphorylation, nuclear translocation, and Smad-dependent gene transcription). The blockade of TGF-β, by a neutralizing antibody against active TGF-β, did not modify Gremlin-induced early Smad activation. These data show that Gremlin directly, by a TGF-βindependent process, activates the Smad pathway. In tubular epithelial cells long-term incubation with Gremlin increased TGF-βproduction and caused a sustained Smad activation and a phenotype conversion into myofibroblasts-like cells. Smad 7 overexpression, which blocks Smad 2/3 activation, diminished EMT changes observed in Gremlin-transfected tubuloepithelial cells. TGF-βneutralization also diminished Gremlin-induced EMT changes. In conclusion, we propose that Gremlin could participate in renal fibrosis by inducing EMT in tubular epithelial cells through activation of Smad pathway and induction of TGF-β.

2020 ◽  
Vol 134 (21) ◽  
pp. 2873-2891
Author(s):  
Sarah W.Y. Lok ◽  
Wai Han Yiu ◽  
Hongyu Li ◽  
Rui Xue ◽  
Yixin Zou ◽  
...  

Abstract Protease-activated receptor (PAR)-1 has emerged as a key profibrotic player in various organs including kidney. PAR-1 activation leads to deposition of extracellular matrix (ECM) proteins in the tubulointerstitium and induction of epithelial–mesenchymal transition (EMT) during renal fibrosis. We tested the anti-fibrotic potential of vorapaxar, a clinically approved PAR-1 antagonist for cardiovascular protection, in an experimental kidney fibrosis model of unilateral ureteral obstruction (UUO) and an AKI-to-chronic kidney disease (CKD) transition model of unilateral ischemia–reperfusion injury (UIRI), and dissected the underlying renoprotective mechanisms using rat tubular epithelial cells. PAR-1 is activated mostly in the renal tubules in both the UUO and UIRI models of renal fibrosis. Vorapaxar significantly reduced kidney injury and ameliorated morphologic changes in both models. Amelioration of kidney fibrosis was evident from down-regulation of fibronectin (Fn), collagen and α-smooth muscle actin (αSMA) in the injured kidney. Mechanistically, inhibition of PAR-1 inhibited MAPK ERK1/2 and transforming growth factor-β (TGF-β)-mediated Smad signaling, and suppressed oxidative stress, overexpression of pro-inflammatory cytokines and macrophage infiltration into the kidney. These beneficial effects were recapitulated in cultured tubular epithelial cells in which vorapaxar ameliorated thrombin- and hypoxia-induced TGF-β expression and ECM accumulation. In addition, vorapaxar mitigated capillary loss and the expression of adhesion molecules on the vascular endothelium during AKI-to-CKD transition. The PAR-1 antagonist vorapaxar protects against kidney fibrosis during UUO and UIRI. Its efficacy in human CKD in addition to CV protection warrants further investigation.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jinyun Pu ◽  
Yu Zhang ◽  
Jianhua Zhou

Epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells is a vital mechanism of renal fibrosis. Mounting evidence suggests that miR-200a expression decreases in tubular epithelial cells in unilateral ureteral obstruction (UUO) rats. Moreover, it has been demonstrated that Huai Qi Huang (HQH) can ameliorate tubulointerstitial damage in adriamycin nephrosis and delay kidney dysfunction in primary glomerular disease. However, the effect of HQH on EMT of tubular epithelial cells in UUO rats and its molecular mechanism is unclear. In order to explore the effect of HQH on EMT and its molecular mechanism in renal fibrosis,in vitroandin vivoexperiments were performed in our study. Our results showed that HQH increased miR-200a expression in UUO rats and in TGF-β1 stimulated NRK-52E cells. Meanwhile, HQH decreased ZEB1 and ZEB2 (the transcriptional repressors of E-cadherin),α-SMA expression in renal tubular epithelial cellsin vitroandin vivo. Furthermore, we found that HQH protected kidney from fibrosis in UUO rats. The results demonstrated that HQH regulated miR-200a/ZEBs pathway and inhibited EMT process, which may be a mechanism of protecting effect on tubular cells in renal fibrosis.


2009 ◽  
Vol 297 (3) ◽  
pp. F729-F739 ◽  
Author(s):  
Hyunjin Noh ◽  
Eun Young Oh ◽  
Ji Yeon Seo ◽  
Mi Ra Yu ◽  
Young Ok Kim ◽  
...  

Excessive accumulation of extracellular matrix (ECM) in the kidneys and epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells contributes to the renal fibrosis that is associated with diabetic nephropathy. Histone deacetylase (HDAC) determines the acetylation status of histones and thereby controls the regulation of gene expression. This study examined the effect of HDAC inhibition on renal fibrosis induced by diabetes or transforming growth factor (TGF)-β1 and determined the role of reactive oxygen species (ROS) as mediators of HDAC activation. In streptozotocin (STZ)-induced diabetic kidneys and TGF-β1-treated normal rat kidney tubular epithelial cells (NRK52-E), we found that trichostatin A, a nonselective HDAC inhibitor, decreased mRNA and protein expressions of ECM components and prevented EMT. Valproic acid and class I-selective HDAC inhibitor SK-7041 also showed similar effects in NRK52-E cells. Among the six HDACs tested (HDAC-1 through -5 and HDAC-8), HDAC-2 activity significantly increased in the kidneys of STZ-induced diabetic rats and db/db mice and TGF-β1-treated NRK52-E cells. Levels of mRNA expression of fibronectin and α-smooth muscle actin were decreased, whereas E-cadherin mRNA was increased when HDAC-2 was knocked down using RNA interference in NRK52-E cells. Interestingly, hydrogen peroxide increased HDAC-2 activity, and the treatment with an antioxidant, N-acetylcystein, almost completely reduced TGF-β1-induced activation of HDAC-2. These findings suggest that HDAC-2 plays an important role in the development of ECM accumulation and EMT in diabetic kidney and that ROS mediate TGF-β1-induced activation of HDAC-2.


2020 ◽  
Author(s):  
Jin-Yun Pu ◽  
Li-Xia Wang ◽  
Jie Wang ◽  
Yu Zhang ◽  
Jian-Hua Zhou

AbstractObjectiveWe aimed to explore the role of ubiquitin-specific peptidase-4 (USP4) in TGF-β1 induced epithelial-mesenchymal transition (EMT) during renal fibrosis, and investigated that if Akt inactivation exerted a critical effect on EMT via USP4/TβRI pathway.MethodsUSP4, pAkt and TβRI proteins in the obstructed kidneys from unilateral ureteral obstruction (UUO) rats were detected by immunohistochemistry assay or western blot method. E-cadherin, α-SMA, USP4 and pAkt protein expression in NRK-52E cells at different concentration of TGF-β1 were detected at different time. Further, NRK-52E cells were transfected with USP4-specific siRNA (si-USP4), and then stimulated with 10 ng/ml TGF-β1 for 24h to detect E-cadherin, α-SMA, E-cadherin and TβRI by immunofluorescent double staining assay. Pretreated with PI3K inhibitor LY294002, protein expression levels of pAkt, E-cadherin, α-SMA were detected. Meanwhile, the location of USP4 was visualized by immunofluorescent assay in NRK-52E cells.ResultsThe expression of USP4 and TβRI was significantly upregulated in the tubular epithelial cells of UUO rats. We also found that TGF-β1 upregulated USP4 and activated Akt in NRK-52E cells during EMT. In vitro, downregulation of USP4 inhibited TβRI expression and partially reversed EMT stimulated by TGF-β1. In the meantime, blunted phosphorylation of Akt with LY294002 promoted the E-cadherin expression, and inhibited α-SMA expression in response to TGF-β1. However, inactivation of Akt could reverse EMT process, but failed to induce USP4 to shuttle between the nucleus and the cytoplasm in NRK-52E cells stimulated by TGF-β1.ConclusionsThese data implied that USP4 was a harmful molecule induced by TGF-β1, regulated by Akt activation and promoted TGF-β1-induced EMT via TβRI in tubular epithelial cells during renal fibrosis.


Reproduction ◽  
2017 ◽  
Vol 154 (1) ◽  
pp. 79-92 ◽  
Author(s):  
Min An ◽  
Dong Li ◽  
Ming Yuan ◽  
Qiuju Li ◽  
Lu Zhang ◽  
...  

Endometrial cells and microenvironment are two important factors in the pathogenesis of adenomyosis. Our previous study demonstrated that macrophages can induce eutopic epithelial cells of adenomyosis to suffer from epithelial–mesenchymal transition (EMT). The aim of this study is to detect whether macrophages interacting with epithelial cells equally induce the EMT process in normal and eutopic endometria of healthy and adenomyotic patients; and whether macrophages parallelly polarize to M2. We investigated the expression levels of epithelial cadherin (E-cadherin), neural cadherin (N-cadherin), cytokeratin7 (CK7), vimentin, transforming growth factor-β1 (TGFB1), SMAD3 and pSMAD3 using immunohistochemistry and western blot, and then estimated the genetic levels of CD163, IL10 and MMP12 using real-time quantitative polymerase chain reaction (RT-PCR) in macrophages. Eutopic and normal endometrial tissues were obtained from 20 patients with adenomyosis and 11 control patients without adenomyosis, respectively. The immunohistochemical analysis shows distinct EMT in eutopic endometria in secretory phase; the expression levels of TGFB1, SMAD3 and pSMAD3 that indicate signal pathway of EMT were also higher in secretory phase. Macrophages can induce EMT process in primary endometrial epithelial cells derived from normal and eutopic endometria. After co-culturing, THP-1-derived macrophages polarized to M2. Compared with the eutopic endometrium group, further polarization to M2 was observed in the normal endometrium group. These results indicate that adenomyosis may be promoted by the pathologic EMT of epithelial cells, which is induced by macrophages that incapably polarize to M2.


Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 476 ◽  
Author(s):  
Chia-Jung Li ◽  
Pei-Yi Chu ◽  
Giou-Teng Yiang ◽  
Meng-Yu Wu

The transforming growth factor-β (TGF-β) signaling pathway plays multiple regulatory roles in the tumorigenesis and development of cancer. TGF-β can inhibit the growth and proliferation of epithelial cells and induce apoptosis, thereby playing a role in inhibiting breast cancer. Therefore, the loss of response in epithelial cells that leads to the inhibition of cell proliferation due to TGF-β is a landmark event in tumorigenesis. As tumors progress, TGF-β can promote tumor cell invasion, metastasis, and drug resistance. At present, the above-mentioned role of TGF-β is related to the interaction of multiple signaling pathways in the cell, which can attenuate or abolish the inhibition of proliferation and apoptosis-promoting effects of TGF-β and enhance its promotion of tumor progression. This article focuses on the molecular mechanisms through which TGF-β interacts with multiple intracellular signaling pathways in tumor progression and the effects of these interactions on tumorigenesis.


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