Modulation of the transactivation function of nuclear factor-kappaB by lipopolysaccharide in RAW264.7 macrophages.
In macrophages, nuclear factor kappa B (NF-kappaB) activation has important roles for the regulation of an inducible nitric oxide synthase (iNOS), several pro-inflammatory cytokines, and anti-apoptotic proteins. In order to analyze the transactivation process of NF-kappaB by lipopolysaccharide (LPS), we used the GAL4-NF-kappaB-p65 fusion protein. This chimeric NF-kappaB is activated transcriptionally only if NF-kappaB transactivation domain is active. With this system, we found that LPS can enhance the transactivation of GAL-NF-kappaB-p65 subunit independent of DNA binding ability and inhibitor of kappaB (IkappaB) regulation. Interestingly, this transactivation by LPS was eliminated with the treatment of U0126, specific inhibitor of mitogen-activated protein kinase (MAPK) kinases (MEKs) 1/2 which has little effect on NF-kappaB activation. We also investigated the effect of inhibitors of apoptosis (IAPs), which might be involved in LPS responses and c-Jun amino terminal kinase (JNKs) activation, on the transactivation of GAL-NF-kappaB-p65. The cIAP1, cIAP2 and XIAP could enhance the NF-kappaB transcription and the chimeric NF-kappaB-p65 transactivation. However, survivin decreased the NF-kappaB transcription and did not influence significantly the chimeric NF-kappaB-p65 transactivation. Taken together, LPS-dependent NF-kappaB transactivation may be involved in extracellular signal-regulated kinase (ERK) pathway and IAPs.
Jung
Sang Won
SW
Institute of Biotechnology, Chungnam National University, Daejeon 305-764, Korea.
Lee
Mi Hee
MH
Kim
Yong Chan
YC
Paik
Sang-Gi
SG
Choi
Yung Hyun
YH
Kim
Young Sang
YS
Kang
Kwang Il
KI
D000818:Animals; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D002460:Cell Line; D051034:Inhibitor of Apoptosis Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology; D016328:NF-kappa B / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis; D010455:Peptides / Q000494:pharmacology; D011506:Proteins / Q000502:physiology; D013467:Sulindac / Q000494:pharmacology; D051996:Transcription Factor RelA; D015533:Transcriptional Activation / Q000187:drug effects*; D044767:Ubiquitin-Protein Ligases
D051034:Inhibitor of Apoptosis Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010455:Peptides; D011506:Proteins; C118258:SN50 peptide; D051996:Transcription Factor RelA; D013467:Sulindac; D009569:Nitric Oxide; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; C494834:Birc2 protein, mouse; C494835:Birc3 protein, mouse; D044767:Ubiquitin-Protein Ligases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3