Thrombin-Induced CCAAT/Enhancer-Binding Protein β Activation and IL-8/CXCL8 Expression via MEKK1, ERK, and p90 Ribosomal S6 Kinase 1 in Lung Epithelial Cells

被引：20

作者：

Lin, Chien-Huang ^{[1
]}

Nai, Po-Ling ^{[1
]}

Bien, Mauo-Ying ^{[2
,3
]}

Yu, Chung-Chi ^{[1
]}

Chen, Bing-Chang ^{[2
]}

机构：

[1] Taipei Med Univ, Coll Med, Grad Inst Med Sci, Taipei 110, Taiwan

[2] Taipei Med Univ, Sch Resp Therapy, Coll Med, Taipei 110, Taiwan

[3] Taipei Med Univ Hosp, Dept Internal Med, Taipei 110, Taiwan

来源：

JOURNAL OF IMMUNOLOGY | 2014年 / 192卷 / 01期

关键词：

NF-KAPPA-B; GENE-EXPRESSION; STATUS-ASTHMATICUS; INTERLEUKIN-8; IL-8; RECEPTORS; PHOSPHORYLATION; TRANSACTIVATION; MACROPHAGES; PATHWAYS;

D O I：

10.4049/jimmunol.1203323

中图分类号：

R392 [医学免疫学]; Q939.91 [免疫学];

学科分类号：

100102 ;

摘要：

Thrombin, a serine protease, is a well-known coagulation factor generated during vascular injury and plays an important role in lung inflammation. We previously showed that the c-Src- and Rac/PI3K/Akt-dependent NF-kappa B pathways are involved in thrombin-induced IL-8/CXCL8 expression in human lung epithelial cells (A549). In this study, we investigated the role of the MEK kinase (MEKK)1/ERK/p90 ribosomal S6 kinase (RSK)1-dependent C/EBP beta signaling pathway in thrombin-induced IL-8/CXCL8 expression. Thrombin-induced IL-8/CXCL8 release and IL-8/CXCL8-luciferase activity were attenuated by small interfering RNA (siRNA) of C/EBP beta and by cells transfected with the C/EBP beta site mutation of the IL-8/CXCL8 construct. Moreover, thrombin-induced kappa B-luciferase activity was also inhibited by C/EBP beta siRNA. The thrombin-induced increases in IL-8/CXCL8 release and IL-8/CXCL8-luciferase were also inhibited by MEKK1 siRNA, PD98059 (an MEK inhibitor), U0126 (an ERK inhibitor), and RSK1 siRNA. Treatment of cells with thrombin caused an increase in C/EBP beta phosphorylation at Thr(235), C/EBP beta-luciferase activity, recruitment of C/EBP beta to the IL-8/CXCL8 promoter, and C/EBP beta-specific DNA complex formation. Furthermore, thrombin-mediated C/EBP beta phosphorylation and C/EBP beta-luciferase activity were inhibited by MEKK1 siRNA, PD98059, and RSK1 siRNA. Stimulation of cells with thrombin resulted in an increase in RSK1 phosphorylation at Thr(359)/Ser(363), and this effect was inhibited by MEKK1 siRNA and PD98059. The thrombin-induced increase in ERK activation was inhibited by MEKK1 siRNA. These results imply that thrombin activates the MEKK1/ERK/RSK1 signaling pathway, which in turn initiates C/EBP beta activation, recruitment of C/EBP beta to the IL-8/CXCL8 promoter, and C/EBP beta-specific DNA complex formation, and ultimately induces IL-8/CXCL8 expression and release in lung epithelial cells.

引用

页码：338 / 348

页数：11