TY - JOUR
T1 - Neutrophil elastase induces IL-8 synthesis by lung epithelial cells via the mitogen-activated protein kinase pathway
AU - Chen, Hao Cheng
AU - Lin, Horng Chyuan
AU - Liu, Chien Ying
AU - Wang, Chun Hua
AU - Hwang, Tritium
AU - Huang, Tzu Ting
AU - Lin, Chien-Huang
AU - Kuo, Han Pin
PY - 2004
Y1 - 2004
N2 - The sequestration of neutrophils in the lung and the release of proinflammatory mediators, including neutrophil elastase, are responsible for sepsis-induced microvascular permeability and alveolar epithelial cell damage. To assess the underlying mechanism, human neutrophil elastase (0.01-0.5 μg/ml) was added to cultured A549 epithelial cells in the presence or absence of inhibitors. IL-8 was analyzed by ELISA or by RT-PCR to measure the IL-8 synthesis capacity. Mitogen-activated protein kinase (MAPK) activity was detected by Western blot analysis. Neutrophil elastase dose-dependently increased IL-8 release from cultured A549 epithelial cells. Pretreatment with a specific elastase inhibitor, elastase inhibitor II (at 0.5, 5, and 50 μg/ml), dose-dependently inhibited neutrophil elastase-induced IL-8 release. The activities of MAPK, p38, and extracellular signal-regulated kinase (ERK) were upregulated by neutrophil elastase. Nuclear transcriptional factor-kappa B (NF-κB) and activator protein 1 (AP-1) were also activated. These responses were significantly inhibited by elastase inhibitor II. A specific inhibitor of p38 MAPK (SB203580) and an NF-κB inhibitor (pyrrolidine dithiocarbamate), but not an ERK inhibitor (PD 98059), significantly inhibited neutrophil elastase-induced IL-8 release and mRNA expression. The specific tyrosine kinase inhibitor, genistein, and the protein kinase C (PKC) inhibitor, Ro 31-8220, also inhibited IL-8 release and mRNA expression as well as p38 and NF-κB activation. There was no significant effect by the protein kinase A inhibitor, H-89, on neutrophil elastase-induced IL-8 synthesis or p38 MAPK activation. Our results indicate that neutrophil elastase activates p38 MAPK which upregulates NF-κB and AP-1 activities, thus inducing IL-8 mRNA expression and protein synthesis. Tyrosine kinase and PKC are implicated in neutrophil elastase activation of the MAPK pathway.
AB - The sequestration of neutrophils in the lung and the release of proinflammatory mediators, including neutrophil elastase, are responsible for sepsis-induced microvascular permeability and alveolar epithelial cell damage. To assess the underlying mechanism, human neutrophil elastase (0.01-0.5 μg/ml) was added to cultured A549 epithelial cells in the presence or absence of inhibitors. IL-8 was analyzed by ELISA or by RT-PCR to measure the IL-8 synthesis capacity. Mitogen-activated protein kinase (MAPK) activity was detected by Western blot analysis. Neutrophil elastase dose-dependently increased IL-8 release from cultured A549 epithelial cells. Pretreatment with a specific elastase inhibitor, elastase inhibitor II (at 0.5, 5, and 50 μg/ml), dose-dependently inhibited neutrophil elastase-induced IL-8 release. The activities of MAPK, p38, and extracellular signal-regulated kinase (ERK) were upregulated by neutrophil elastase. Nuclear transcriptional factor-kappa B (NF-κB) and activator protein 1 (AP-1) were also activated. These responses were significantly inhibited by elastase inhibitor II. A specific inhibitor of p38 MAPK (SB203580) and an NF-κB inhibitor (pyrrolidine dithiocarbamate), but not an ERK inhibitor (PD 98059), significantly inhibited neutrophil elastase-induced IL-8 release and mRNA expression. The specific tyrosine kinase inhibitor, genistein, and the protein kinase C (PKC) inhibitor, Ro 31-8220, also inhibited IL-8 release and mRNA expression as well as p38 and NF-κB activation. There was no significant effect by the protein kinase A inhibitor, H-89, on neutrophil elastase-induced IL-8 synthesis or p38 MAPK activation. Our results indicate that neutrophil elastase activates p38 MAPK which upregulates NF-κB and AP-1 activities, thus inducing IL-8 mRNA expression and protein synthesis. Tyrosine kinase and PKC are implicated in neutrophil elastase activation of the MAPK pathway.
KW - Alveolar epithelial cells
KW - Elastase
KW - IL-8
KW - Mitogen-activated protein kinase
UR - http://www.scopus.com/inward/record.url?scp=0942300674&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0942300674&partnerID=8YFLogxK
U2 - 10.1159/000075288
DO - 10.1159/000075288
M3 - Article
C2 - 14730209
AN - SCOPUS:0942300674
VL - 11
SP - 49
EP - 58
JO - Journal of Biomedical Science
JF - Journal of Biomedical Science
SN - 1021-7770
IS - 1
ER -