Gremlin Is a Downstream Profibrotic Mediator of Transforming Growth Factor-Beta in Cultured Renal Cells
Gremlin Is a Downstream Profibrotic Mediator of Transforming Growth Factor-Beta in Cultured Renal Cells
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DOI：
10.1159/000346575
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发表时间：
2012-01-01
影响因子：
--
通讯作者：
Ruiz-Ortega, Marta
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文献类型：
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作者：
Rodrigues-Diez, Raquel;Lavoz, Carolina;Ruiz-Ortega, Marta
背景/目的：慢性肾脏疾病的特点是细胞外基质在肾小管间质区积聚。成纤维细胞是主要的基质生成细胞。活化成纤维细胞的一个来源是上皮间充质转化（EMT）。在培养的小管上皮细胞中，转化生长因子- β (tgf - β(1))诱导与EMT表型变化相关的Gremlin产生，因此Gremlin被认为是下游tgf - β(1)介质。Gremlin是一种在与基质积累相关的慢性肾脏疾病中上调的发育性基因，但其在肾纤维化调节中的直接作用及其与tgf - β的关系尚未被研究。方法：对小鼠肾成纤维细胞和人肾小管上皮细胞进行研究。采用Western blot/共聚焦显微镜或实时荧光定量PCR检测关键促纤维化因子、细胞外基质蛋白（ECM）和EMT标志物。小干扰RNA靶向内源性Gremlin。结果：在小鼠成纤维细胞中，重组Gremlin刺激上调了原纤维化基因，如tgf - β(1)，并增加了包括I型胶原在内的ECM蛋白的产生。用小干扰RNA阻断内源性Gremlin可抑制tgf - β(1)诱导的ECM上调。在小管上皮细胞中，Gremlin也增加了促纤维化基因并引起了EMT的变化：表型调节到肌成纤维细胞样形态，上皮标记物的丢失和间充质标记物的诱导。此外，Gremlin基因沉默抑制tgf - β(1)诱导的EMT变化。结论：Gremlin直接激活培养的肾成纤维细胞和肾小管上皮细胞的促纤维化事件。此外，内源性Gremlin阻断可抑制tgf - β介导的基质生成和EMT，表明Gremlin可能是肾纤维化的新治疗靶点。巴塞尔S. Karger股份有限公司版权所有
Background/Aims: Chronic kidney disease is characterized by accumulation of extracellular matrix in the tubulointerstitial area. Fibroblasts are the main matrix-producing cells. One source of activated fibroblasts is the epithelial mesenchymal transition (EMT). In cultured tubular epithelial cells, transforming growth factor-beta (TGF-beta(1)) induced Gremlin production associated with EMT phenotypic changes, and therefore Gremlin has been proposed as a downstream TGF-beta(1) mediator. Gremlin is a developmental gene upregulated in chronic kidney diseases associated with matrix accumulation, but its direct role in the modulation of renal fibrosis and its relation with TGF-beta has not been investigated. Methods: Murine renal fibroblasts and human tubular epithelial cells were studied. Renal fibrosis was determined by evaluation of key profibrotic factors, extracellular matrix proteins (ECM) and EMT markers by Western blot/confocal microscopy or real-time PCR. Endogenous Gremlin was targeted with small interfering RNA. Results: In murine fibroblasts, stimulation with recombinant Gremlin upregulated profibrotic genes, such as TGF-beta(1), and augmented the production of ECM proteins, including type I collagen. The blockade of endogenous Gremlin with small interfering RNA inhibited TGF-beta(1)-induced ECM upregulation. In tubular epithelial cells Gremlin also increased profibrotic genes and caused EMT changes: phenotypic modulation to myofibroblast-like morphology, loss of epithelial markers and induction of mesenchymal markers. Moreover, Gremlin gene silencing inhibited TGF-beta(1)-induced EMT changes. Conclusions: Gremlin directly activates profibrotic events in cultured renal fibroblasts and tubular epithelial cells. Moreover, endogenous Gremlin blockade inhibited TGF-beta-mediated matrix production and EMT, suggesting that Gremlin could be a novel therapeutic target for renal fibrosis. Copyright (C) 2013 S. Karger AG, Basel