TY - JOUR
T1 - Regulation of TNF-α expression in normal macrophages
T2 - The role of C/EBPβ
AU - Pope, Richard
AU - Mungre, Shubangee
AU - Liu, Hongtao
AU - Thimmapaya, Bayar
N1 - Funding Information:
This work was supported in part by an NIH grant (ROI AR43642), and by an NIH Multipurpose Arthritis and Musculoskeletal Diseases Center grant (P60 AR30692). We thank Harris Perlman and Constantinos Georganas for careful review of the manuscript.
PY - 2000/8
Y1 - 2000/8
N2 - C/EBPβ is present in monocytes and macrophages, binds to the proximal region of the TNF-α promoter, and contributes to its regulation. This study was performed to characterize the ability of C/EBPβ to regulate the TNF-α gene in myelomonocytic cells and primary macrophages. In transient transfection assays, overexpression of wild type C/EBPβ resulted in a 3-4-fold activation of a 120 base pair TNF-α promoter-reporter construct, while overexpression of a dominant negative (DN) C/EBPβ inhibited LPS-induced activation. In vitro monocyte-differentiated macrophages, infected with an adenoviral vector expressing the DN C/EBPβ (AdDNC/EBPβ) or the control Adβgal, expressed their transgenes weakly, however expression was greatly enhanced in the presence of PMA. Infection with AdDNC/EBPβ resulted in 60% suppression of LPS induced TNFα secretion compared to Adβgal infection (P < 0.001) in PMA-treated macrophages. Northern blot analysis demonstrated approximately a 40% reduction of the TNF-α mRNA in the presence of the DN C/EBPβ, suggesting that the effect of the DN C/EBPβ was at the transcriptional level. In contrast, AdDNC/EBPβ infection did not result in inhibition of LPS-induced TNF-α secretion in the absence of PMA. Further, DN versions of both C/EBPβ and c-Jun, but not NF-κB p65, suppressed PMA-induced TNF-α secretion in macrophages. These observations demonstrate that, C/EBPβ and c-Jun contribute to the regulation of the TNF-α gene in normal macrophages following treatment with PMA. (C) 2000 Academic Press.
AB - C/EBPβ is present in monocytes and macrophages, binds to the proximal region of the TNF-α promoter, and contributes to its regulation. This study was performed to characterize the ability of C/EBPβ to regulate the TNF-α gene in myelomonocytic cells and primary macrophages. In transient transfection assays, overexpression of wild type C/EBPβ resulted in a 3-4-fold activation of a 120 base pair TNF-α promoter-reporter construct, while overexpression of a dominant negative (DN) C/EBPβ inhibited LPS-induced activation. In vitro monocyte-differentiated macrophages, infected with an adenoviral vector expressing the DN C/EBPβ (AdDNC/EBPβ) or the control Adβgal, expressed their transgenes weakly, however expression was greatly enhanced in the presence of PMA. Infection with AdDNC/EBPβ resulted in 60% suppression of LPS induced TNFα secretion compared to Adβgal infection (P < 0.001) in PMA-treated macrophages. Northern blot analysis demonstrated approximately a 40% reduction of the TNF-α mRNA in the presence of the DN C/EBPβ, suggesting that the effect of the DN C/EBPβ was at the transcriptional level. In contrast, AdDNC/EBPβ infection did not result in inhibition of LPS-induced TNF-α secretion in the absence of PMA. Further, DN versions of both C/EBPβ and c-Jun, but not NF-κB p65, suppressed PMA-induced TNF-α secretion in macrophages. These observations demonstrate that, C/EBPβ and c-Jun contribute to the regulation of the TNF-α gene in normal macrophages following treatment with PMA. (C) 2000 Academic Press.
KW - C/EBPβ
KW - LPS
KW - Macrophages
KW - PMA
KW - TNF-α
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U2 - 10.1006/cyto.2000.0691
DO - 10.1006/cyto.2000.0691
M3 - Article
C2 - 10930293
AN - SCOPUS:0033858317
VL - 12
SP - 1171
EP - 1181
JO - Cytokine
JF - Cytokine
SN - 1043-4666
IS - 8
ER -