Thioredoxin facilitates the induction of heme oxygenase-1 in response to inflammatory mediators.
Heme oxygenase (HO)-1 is a stress response protein that is regulated by oxidative stress. HO-1 catalyzes the generation of biliverdin, carbon monoxide, and iron from heme. Lipopolysaccharide (LPS) and interleukin (IL)-1beta induce HO-1 through the binding of nuclear proteins to AP-1 motifs in enhancer regions upstream from the transcription start site. The DNA binding activity of AP-1 proteins depends on the reduction of cysteines in their DNA-binding domains. We found that agents that disrupt free sulfhydryl groups abolish AP-1 binding activity in nuclear proteins obtained from rat aortic smooth muscle cells and macrophages stimulated with IL-1beta or LPS. Thioredoxin (TRX) may regulate the redox status of nuclear transcription factors in response to oxidative stimuli, thus we determined the role of TRX in the physiologic regulation of HO-1. TRX underwent nuclear translocation in cells stimulated with IL-1beta and LPS. We transfected macrophages with a heterologous promoter construct containing two AP-1 sites from an upstream enhancer region in the HO-1 promoter. Recombinant TRX induced promoter activity to a level analogous to that induced by LPS, and this TRX response was abolished by mutation of the AP-1 sites. An inhibitor of TRX reductase, used to prevent TRX translocation in the reduced state, decreased HO-1 induction by IL-1beta and LPS. These data provide the first evidence that TRX contributes to the induction of HO-1 by inflammatory mediators.
Wiesel
P
P
Program of Developmental Cardiovascular Biology, Cardiovascular Division and the Pulmonary and Critical Care Division, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Foster
L C
LC
Pellacani
A
A
Layne
M D
MD
Hsieh
C M
CM
Huggins
G S
GS
Strauss
P
P
Yet
S F
SF
Perrella
M A
MA
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000201:enzymology; D019757:Carbon-Oxygen Lyases / Q000235:genetics; D002460:Cell Line; D002478:Cells, Cultured; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D004742:Enhancer Elements, Genetic; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006367:HeLa Cells; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis / Q000235:genetics*; D051547:Heme Oxygenase-1; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000201:enzymology*; D008297:Male; D008565:Membrane Proteins; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology*; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D013879:Thioredoxins / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection
D007375:Interleukin-1; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D018808:Transcription Factor AP-1; D013879:Thioredoxins; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D019757:Carbon-Oxygen Lyases; C085108:APEX1 protein, human; C470319:Apex1 protein, rat; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase