tPA protects renal interstitial fibroblasts and myofibroblasts from apoptosis
tPA protects renal interstitial fibroblasts and myofibroblasts from apoptosis
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tPA 保护肾间质成纤维细胞和肌成纤维细胞免于凋亡
DOI：
10.1681/asn.2007030300
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发表时间：
2008-03-01
影响因子：
13.6
通讯作者：
Liu, Youhua
中科院分区：
文献类型：
--
作者：
Hu, Kebin;Lin, Ling;Liu, Youhua
间质成纤维细胞和肌成纤维细胞的活化和扩增在肾纤维化的演变中起重要作用。在阻塞性损伤后，缺乏组织型纤溶酶原激活物（tPA）的小鼠比野生型对照组具有更少的肌成纤维细胞和更少的间质纤维化。这表明tPA控制体内成纤维细胞/肌成纤维细胞群体的大小，本研究试图确定潜在的机制。在体外，tPA抑制staurosporine或H2 O2诱导的caspase-3激活，防止细胞DNA片段化，并抑制细胞色素C从线粒体释放到细胞质中的大鼠间质成纤维细胞系（NRK-49 F）。tPA还保护TGF-β 1激活的肌成纤维细胞免于凋亡。tPA的这种抗凋亡作用不依赖于其蛋白酶活性，但需要其膜受体LDL受体相关蛋白1（LRP-1）。删除或敲低LRP-1废除tPA介导的细胞存活，而在小鼠LRP-1缺陷成纤维细胞系（PEA-13）中重新引入LRP-1小基因恢复了tPA的细胞保护能力。tPA触发了涉及细胞外信号调节激酶1/2（Erk 1/2）、p90 RSK和Bad磷酸化的生存信号级联。阻断Erk 1/2的激活可消除tPA的抗凋亡作用，而组成型活性MEK 1的表达可促进细胞存活，这与tPA相似。在体内，与野生型对照组相比，梗阻性损伤后tPA（-/-）小鼠间质肌成纤维细胞凋亡增加，梗阻缓解后4周肌成纤维细胞完全耗尽。总之，这些发现表明tPA是一种存活因子，通过LRP-1-、Erk 1/2-、p90 RSK-和Bad依赖性机制阻止肾间质成纤维细胞和肌成纤维细胞凋亡。
Activation and expansion of interstitial fibroblasts and myofibroblasts play an essential role in the evolution of renal fibrosis. After obstructive injury, mice lacking tissue-type plasminogen activator (tPA) have fewer myofibroblasts and less interstitial fibrosis than wild-type controls. This suggests that tPA controls the size of the fibroblast/myofibroblast population in vivo, and this study sought to determine the underlying mechanism. In vitro, tPA inhibited staurosporine or H2O2-induced caspase-3 activation, prevented cellular DNA fragmentation, and suppressed the release of cytochrome C from mitochondria into the cytosol in a rat interstitial fibroblast cell line (NRK-49F). tPA also protected TGF-beta 1-activated myofibroblasts from apoptosis. This antiapoptotic effect of tPA was independent of its protease activity but required its membrane receptor, the LDL receptor-related protein 1 (LRP-1). Deletion or knockdown of LRP-1 abolished tPA-mediated cell survival, whereas re-introduction of an LRP-1 minigene in a mouse LRP-1-deficient fibroblast cell line (PEA-13) restored the cytoprotective ability of tPA. tPA triggered a cascade of survival signaling involving extracellular signal-regulated kinase 1/2 (Erk1/2), p90RSK, and phosphorylation of Bad. Blockade of Erk1/2 activation abrogated the antiapoptotic effect of tPA, whereas expression of constitutively active MEK1 promoted cell survival similar to tPA. In vivo, compared with wild-type controls, apoptosis of interstitial myofibroblasts was increased in tPA(-/-) mice after obstructive injury, and myofibroblasts were completely depleted 4 wk after relief of the obstruction. Together, these findings illustrate that tPA is a survival factor that prevents apoptosis of renal interstitial fibroblasts and myofibroblasts through an LRP-1-, Erk1/2-, p90RSK-, and Bad-dependent mechanism.