Role of NF-kappaB and p38 MAP kinase signaling pathways in the lipopolysaccharide-dependent activation of heme oxygenase-1 gene expression.
Heme oxygenase (HO)-1 is the inducible isoform of the rate-limiting enzyme of heme degradation, which is up-regulated by a host of stress stimuli. The bacterial cell membrane component lipopolysaccharide (LPS) is a prototypical activator of monocytic cells. Here, it is shown that LPS induced the endogenous HO-1 gene expression in RAW264.7 monocytic cells. To investigate the molecular mechanisms of HO-1 gene induction by LPS, we performed transfection experiments with reporter gene constructs containing sequences of the proximal rat HO-1 gene promoter. Deletion and mutation analysis indicated that a cyclic AMP response element/activator protein-1 site (-664/-657), but not an E-box motif (-47/-42), played a major role for LPS-dependent HO-1 gene induction. Up-regulation of HO-1 promoter activity by LPS was decreased by pharmacological nuclear factor-kappaB (NF-kappaB) inhibitors and by cotransfected expression vectors with dominant negative isoforms of NF-kappaB-inducing kinase, inhibitor of NF-kappaB (IkappaB) kinase beta, and IkappaBalpha. Moreover, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and overexpressed dominant negative p38beta decreased, whereas dominant negative p38delta increased, LPS-dependent induction of HO-1 gene expression. The results suggest that the NF-kappaB and p38 MAPK signaling pathways mediate the LPS-dependent induction of HO-1 gene expression via DNA sequences of the proximal promoter region.
Wijayanti
Nastiti
N
Institut für Klinische Chemie und Pathobiochemie, Justus-Liebig-Universität Giessen, D-35392 Giessen, Germany.
Huber
Sebastian
S
Samoylenko
Anatoly
A
Kietzmann
Thomas
T
Immenschuh
Stephan
S
D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation; D004790:Enzyme Induction; D017930:Genes, Reporter; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D008070:Lipopolysaccharides / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051381:Rats; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*; D000097782:NF-kappaB-Inducing Kinase
D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000097782:NF-kappaB-Inducing Kinase; C496542:Hmox1 protein, mouse