TY - JOUR
T1 - LPS-induced G-CSF expression in macrophages is mediated by ERK2, but not ERK1
AU - Chang, Shwu Fen
AU - Lin, Shih Shan
AU - Yang, Hui Ching
AU - Chou, Yuan Yi
AU - Gao, Jhen I.
AU - Lu, Shao Chun
N1 - Publisher Copyright:
© 2015 Chang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2015/6/26
Y1 - 2015/6/26
N2 - Granulocyte colony-stimulating factor (G-CSF) selectively stimulates proliferation and differentiation of neutrophil progenitors which play important roles in host defense against infectious agents. However, persistent G-CSF production often leads to neutrophilia and excessive inflammatory reactions. There is therefore a need to understand the mechanism regulating G-CSF expression. In this study, we showed that U0126, a MEK1/2 inhibitor, decreases lipopolysaccharide (LPS)-stimulated G-CSF promoter activity, mRNA expression and protein secretion. Using short hairpin RNA knockdown, we demonstrated that ERK2, and not ERK1, involves in LPS-induced G-CSF expression, but not LPS-regulated expression of TNF-α. Reporter assays showed that ERK2 and C/EBPβ synergistically activate G-CSF promoter activity. Further chromatin immunoprecipitation (ChIP) assays revealed that U0126 inhibits LPS-induced binding of NF-κB (p50/p65) and C/EBPβ to the G-CSF promoter, but not their nuclear protein levels. Knockdown of ERK2 inhibits LPS-induced accessibility of the G-CSF promoter region to DNase I, suggesting that chromatin remodeling may occur. These findings clarify that ERK2, rather than ERK1, mediates LPS-induced G-CSF expression in macrophages by remodeling chromatin, and stimulates C/ EBPβ-dependent activation of the G-CSF promoter. This study provides a potential target for regulating G-CSF expression.
AB - Granulocyte colony-stimulating factor (G-CSF) selectively stimulates proliferation and differentiation of neutrophil progenitors which play important roles in host defense against infectious agents. However, persistent G-CSF production often leads to neutrophilia and excessive inflammatory reactions. There is therefore a need to understand the mechanism regulating G-CSF expression. In this study, we showed that U0126, a MEK1/2 inhibitor, decreases lipopolysaccharide (LPS)-stimulated G-CSF promoter activity, mRNA expression and protein secretion. Using short hairpin RNA knockdown, we demonstrated that ERK2, and not ERK1, involves in LPS-induced G-CSF expression, but not LPS-regulated expression of TNF-α. Reporter assays showed that ERK2 and C/EBPβ synergistically activate G-CSF promoter activity. Further chromatin immunoprecipitation (ChIP) assays revealed that U0126 inhibits LPS-induced binding of NF-κB (p50/p65) and C/EBPβ to the G-CSF promoter, but not their nuclear protein levels. Knockdown of ERK2 inhibits LPS-induced accessibility of the G-CSF promoter region to DNase I, suggesting that chromatin remodeling may occur. These findings clarify that ERK2, rather than ERK1, mediates LPS-induced G-CSF expression in macrophages by remodeling chromatin, and stimulates C/ EBPβ-dependent activation of the G-CSF promoter. This study provides a potential target for regulating G-CSF expression.
UR - http://www.scopus.com/inward/record.url?scp=84938499450&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84938499450&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0129685
DO - 10.1371/journal.pone.0129685
M3 - Article
C2 - 26114754
AN - SCOPUS:84938499450
SN - 1932-6203
VL - 10
JO - PLoS ONE
JF - PLoS ONE
IS - 6
M1 - e0129685
ER -