Activation of the Epidermal Growth Factor Receptor (EGFR) by a Novel Metalloprotease Pathway
Activation of the Epidermal Growth Factor Receptor (EGFR) by a Novel Metalloprotease Pathway
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DOI：
10.1074/jbc.m803732200
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发表时间：
2008-11-14
影响因子：
4.8
通讯作者：
McElvaney, Noel G.
中科院分区：
文献类型：
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作者：
Bergin, David A.;Greene, Catherine M.;McElvaney, Noel G.
中性粒细胞弹性蛋白酶 (NE) 是一种促炎性蛋白酶，在炎症性疾病期间，肺部的含量高于正常水平。 NE 调节气道上皮细胞产生 IL-8，并可激活 EGFR 和 TLR4。据报道，TACE/ADAM17 可反式激活 EGFR 以响应 NE。在这里，使用 16HBE14o-人支气管上皮细胞，我们展示了 NE 调节这两个事件的新机制。通过明胶和酪蛋白酶谱法仅在来自 NE 处理的细胞的上清液中检测到的高分子量可溶性金属蛋白酶活性通过蛋白质免疫印迹证实为 meprin α。体外研究证明 NE 能够激活 meprin α，进而释放可溶性 TGF α 并诱导 16HBE14o 细胞产生 IL-8。这些作用被放线菌素（一种特定的 meprin 抑制剂）消除了。 meprin α siRNA 也抑制 NE 诱导的 IL-8 表达。免疫沉淀研究在 NE 刺激的细胞中检测到 EGFR/TLR4 复合物，这些细胞过度表达这些受体。共聚焦研究证实了 EGFR 和 TLR4 在经 meprin α 刺激的 16HBE14o 细胞中共定位。 meprin α 还通过这些细胞中的 MyD88 激活 NF kappa B。在气管内感染铜绿假单胞菌的 NE 基因敲除小鼠的支气管肺泡灌洗液中，与对照小鼠相比，meprin α 显着降低，而在囊性纤维化患者而非健康对照个体的支气管肺泡灌洗液中，meprin α 显着增加，且与 NE 活性相关。这些数据描述了一种先前未鉴定的肺金属蛋白酶 meprin α，及其在 NE 诱导的 EGFR 和 TLR4 激活以及 IL-8 产生中的作用。
Neutrophil Elastase (NE) is a pro-inflammatory protease present at higher than normal levels in the lung during inflammatory disease. NE regulates IL-8 production from airway epithelial cells and can activate both EGFR and TLR4. TACE/ADAM17 has been reported to trans-activate EGFR in response to NE. Here, using 16HBE14o-human bronchial epithelial cells we demonstrate anew mechanism by which NE regulates both of these events. A high molecular weight soluble metalloprotease activity detectable only in supernatants from NE-treated cells by gelatin and casein zymography was confirmed to be meprin alpha by Western immunoblotting. In vitro studies demonstrated the ability of NE to activate meprin alpha, which in turn could release soluble TGF alpha and induce IL-8 production from 16HBE14o-cells. These effects were abrogated by actinonin, a specific meprin inhibitor. NE-induced IL-8 expression was also inhibited by meprin alpha siRNA. Immunoprecipitation studies detected EGFR/TLR4 complexes in NE-stimulated cells overexpressing these receptors. Confocal studies confirmed colocalization of EGFR and TLR4 in 16HBE14o-cells stimulated with meprin alpha. NF kappa B was also activated via MyD88 in these cells by meprin alpha. In bronchoalveolar lavage fluid from NE knock-out mice infected intra-tracheally with Pseudomonas aeruginosa meprin alpha was significantly decreased compared with control mice, and was significantly increased and correlated with NE activity, in bronchoalveolar lavage fluid from individuals with cystic fibrosis but not healthy controls. The data describe a previously unidentified lung metalloprotease meprin alpha, and its role in NE-induced EGFR and TLR4 activation and IL-8 production.