TY - JOUR
T1 - Genetic determination of the role of PU.1 in macrophage gene expression
AU - Joo, Myungsoo
AU - Kwon, Minjae
AU - Azim, Anser C.
AU - Sadikot, Ruxana T.
AU - Blackwell, Timothy S.
AU - Christman, John W.
N1 - Funding Information:
This work was supported by The Department of Veterans Affairs and NIH Grants HL061419, HL075557, and HL066196.
PY - 2008/7/18
Y1 - 2008/7/18
N2 - PU.1, an Ets family transcription factor, mediates macrophage effector function in inflammation by regulating gene expression. But, the extent and nature of PU.1 function in gene expression has not been genetically determined because ablation of PU.1 gene abolishes macrophage development. Here, we epigenetically suppressed PU.1 by stably expressing PU.1 specific siRNA in macrophages, and determined the effect of PU.1 deficiency on expressions of key inflammatory genes: Toll-like receptor 4 (TLR4), cyclooxygenease-2 (COX-2), and macrophage inflammatory protein-1α (MIP-1α). PU.1-silenced cell lines expressed lower TLR4 mRNA and COX-2 protein, but higher MIP-1α protein, than controls. Over-expression of PU.1 suppressed lipopolysaccharide-induced MIP-1α production. PU.1 occupied proximal and distal cognate sites in the endogenous MIP-1α promoter, but dissociated only from the distal sites in response to lipopolysaccharide, suggesting a novel negative regulatory mechanism by PU.1. Together, our results defined PU.1 function in differentially regulating expressions of TLR4, COX-2, and MIP-1α.
AB - PU.1, an Ets family transcription factor, mediates macrophage effector function in inflammation by regulating gene expression. But, the extent and nature of PU.1 function in gene expression has not been genetically determined because ablation of PU.1 gene abolishes macrophage development. Here, we epigenetically suppressed PU.1 by stably expressing PU.1 specific siRNA in macrophages, and determined the effect of PU.1 deficiency on expressions of key inflammatory genes: Toll-like receptor 4 (TLR4), cyclooxygenease-2 (COX-2), and macrophage inflammatory protein-1α (MIP-1α). PU.1-silenced cell lines expressed lower TLR4 mRNA and COX-2 protein, but higher MIP-1α protein, than controls. Over-expression of PU.1 suppressed lipopolysaccharide-induced MIP-1α production. PU.1 occupied proximal and distal cognate sites in the endogenous MIP-1α promoter, but dissociated only from the distal sites in response to lipopolysaccharide, suggesting a novel negative regulatory mechanism by PU.1. Together, our results defined PU.1 function in differentially regulating expressions of TLR4, COX-2, and MIP-1α.
KW - COX-2
KW - Epigenetic suppression
KW - Gene regulation
KW - Inflammation
KW - MIP-1α
KW - Macrophages
KW - PU.1
KW - TLR4
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U2 - 10.1016/j.bbrc.2008.04.189
DO - 10.1016/j.bbrc.2008.04.189
M3 - Article
C2 - 18485892
AN - SCOPUS:46349103014
SN - 0006-291X
VL - 372
SP - 97
EP - 102
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -