Plasmin(ogen) promotes renal interstitial fibrosis by promoting epithelial-to-mesenchymal transition:: Role of plasmin-activated signals
Plasmin(ogen) promotes renal interstitial fibrosis by promoting epithelial-to-mesenchymal transition:: Role of plasmin-activated signals
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DOI：
10.1681/asn.2006080886
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发表时间：
2007-03-01
影响因子：
13.6
通讯作者：
Eddy, Allison A.
中科院分区：
文献类型：
--
作者：
Zhang, Guoqiang;Kernan, Kelly A.;Eddy, Allison A.
纤溶酶原（Plg）激活剂抑制剂-1（PAI-1）是一种重要的纤维化促进分子。这种效应是否可归因于 PAI-1 作为纤溶酶生成抑制剂的活性尚有争议。本研究旨在利用体内和体外方法研究 Plg 在肾纤维化中的作用。 Plg 缺陷型 (Plg-/-) 和野生型 (Plg+/+) C57BL/6 小鼠接受单侧输尿管梗阻或假手术（n = 8/组；假手术，第 3、7、14 和 21 天）。 Plg 缺陷通过 Plg mRNA、蛋白质和纤溶酶活性的缺失来证实。单侧输尿管梗阻 21 天后，Plg-/- 小鼠的肾总胶原蛋白显着减少 35%。 Plg-/-小鼠的上皮间质转化 (EMT) 也显着减少，以 E-钙粘蛋白的肾小管丢失和 a-平滑肌肌动蛋白的获得为代表，分别减少 76% 和 50%。 Plg-/- 小鼠 EMT 和纤维化严重程度的减弱与磷酸化细胞外信号调节激酶 (ERK) 和活性 TGF-β 水平的显着降低有关。在体外，向小鼠肾小管上皮细胞培养物中添加纤溶酶（20 μg/ml）会在几分钟内引发 ERK 磷酸化，然后表型转变为成纤维细胞特异性蛋白 1+、α-平滑肌肌动蛋白+、产生纤连蛋白的成纤维细胞样细胞。纤溶酶诱导的 ERK 激活和 EMT 在体外均被蛋白酶激活受体 1 (PAR-1) 沉默 RNA 显着阻断；通过 pepducin，一种特异性抗 PAR-1 信号肽；以及 ERK 激酶抑制剂 U0126。纤溶酶诱导的 ERK 磷酸化在 PAR-1 过表达的肾小管细胞中增强。这些发现支持纤溶酶的重要促纤维化作用，包括 PAR-1 依赖性 ERK 信号传导和 EMT 诱导。
Plasminogen (Plg) activator inhibitor-1 (PAI-1) is an important fibrosis-promoting molecule. Whether this effect can be attributed to PAI-1's activity as an inhibitor of plasmin generation is debated. This study was designed to investigate the role of Plg in renal fibrosis using in vivo and in vitro approaches. Plg-deficient (Plg-/-) and wild-type (Plg+/+) C57BL/6 mice were subjected to unilateral ureteral obstruction or sham surgery (n = 8/group; sham, days 3, 7, 14, and 21). Plg deficiency was confirmed by the absence of Plg mRNA, protein, and plasmin activity. After 21 d of unilateral ureteral obstruction, total kidney collagen was significantly reduced by 35% in the Plg-/- mice. Epithelial-to-mesenchymal transition (EMT), as typified by tubular loss of E-cadherin and acquisition of a-smooth muscle actin, was also significantly reduced in Plg-/-mice, 76% and 50%, respectively. Attenuation of EMT and fibrosis severity in the Plg-/- mice was associated with significantly lower levels of phosphorylated extracellular signal-regulated kinase (ERK) and active TGF-beta. In vitro, addition of plasmin (20 mu g/ml) to cultures of murine tubular epithelial cells initiated ERK phosphorylation within minutes, followed by phenotypic transition to fibroblast-specific protein-1+, alpha-smooth muscle actin+, fibronectin-producing fibroblast-like cells. Both plasmin-induced ERK activation and EMT were significantly blocked in vitro by the protease-activated receptor-1 (PAR-1) silencing RNA; by pepducin, a specific anti-PAR-1 signaling peptide; and by the ERK kinase inhibitor U0126. Plasmin-induced ERK phosphorylation was enhanced in PAR-1-overexpressing tubular cells. These findings support important profibrotic roles for plasmin that include PAR-1-dependent ERK signaling and EMT induction.