Department of Chest Medicine, Taipei Veterans General Hospital, Taiwan.
Life Sci. 2011 Aug 1;89(5-6):204-12. doi: 10.1016/j.lfs.2011.06.008. Epub 2011 Jun 22.
Matrix metalloprotease (MMP)-9 is present in abundance in various chronic airway disorders and is involved in lung remodeling. MMP may cleave membrane-bound precursor proteins and release epidermal growth factor-like ligands that subsequently bind to epidermal growth factor receptor (EGFR). We hypothesized that MMP-9 may stimulate the airway epithelium to produce fibrogenic mediators through activation of membrane-bound receptors.
Human airway epithelial cells were grown on air-liquid interface culture inserts. MMP-9 was employed to stimulate the cells. Conditioned medium following MMP-9 stimulation was co-incubated with human lung fibroblasts.
MMP-9 stimulated human airway epithelial cells to produce transforming growth factor (TGF)-β(1) at both the mRNA and protein level. Using a microarray, increased phosphorylation of EGFR tyrosine kinase (TK) was identified and further confirmed by immunoprecipitation and Western blot analysis. A significant increase in EGF and TGF-α release was observed after MMP-9 had been added for 30min. Protease inhibitor, EGFR monoclonal antibody and EGFR-TK inhibitor blocked this action and subsequent TGF-β(1) production. Neutralizing antibodies against EGF and TGF-α substantially inhibited TGF-β(1) production following MMP-9 stimulation. MMP-9-induced TGF-β(1) production occurred through MAP kinase p44/42 phosphorylation. Selective p44/42 kinase inhibitor UO126 successfully inhibited TGF-β(1) production. Conditioned medium from epithelial cells treated with MMP-9 significantly induced Smad3 phosphorylation and subsequent fibroblast proliferation after 24h culture.
These data indicate that MMP-9 induces TGF-β(1) production in the airway epithelium through the cleavage of EGF and EGF-like ligands and activating EGFR, suggesting potential targets of therapeutic intervention in airway fibrotic disorders.
基质金属蛋白酶（MMP）-9 大量存在于各种慢性气道疾病中，并参与肺重塑。MMP 可能切割膜结合的前体蛋白，并释放表皮生长因子样配体，随后与表皮生长因子受体（EGFR）结合。我们假设 MMP-9 可能通过激活膜结合受体刺激气道上皮细胞产生纤维生成介质。
将人气道上皮细胞在气液界面培养插入物上生长。用 MMP-9 刺激细胞。用 MMP-9 刺激后的条件培养基与肺成纤维细胞共孵育。
MMP-9 刺激人气道上皮细胞在 mRNA 和蛋白水平上产生转化生长因子（TGF）-β（1）。通过微阵列，鉴定到 EGFR 酪氨酸激酶（TK）的磷酸化增加，并通过免疫沉淀和 Western blot 分析进一步证实。在添加 MMP-9 30min 后观察到 EGF 和 TGF-α 的释放显著增加。蛋白酶抑制剂、EGFR 单克隆抗体和 EGFR-TK 抑制剂阻断了这一作用和随后的 TGF-β（1）产生。MMP-9 刺激后，针对 EGF 和 TGF-α 的中和抗体大大抑制了 TGF-β（1）的产生。MMP-9 诱导的 TGF-β（1）产生是通过 MAP 激酶 p44/42 磷酸化发生的。选择性 p44/42 激酶抑制剂 UO126 成功抑制了 TGF-β（1）的产生。用 MMP-9 处理的上皮细胞的条件培养基在 24h 培养后显著诱导 Smad3 磷酸化和随后的成纤维细胞增殖。
这些数据表明，MMP-9 通过切割 EGF 和 EGF 样配体并激活 EGFR 诱导气道上皮细胞产生 TGF-β（1），提示在气道纤维化疾病中治疗干预的潜在靶点。
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