Heme oxygenase-1-derived carbon monoxide requires the activation of transcription factor NF-kappa B to protect endothelial cells from tumor necrosis factor-alpha-mediated apoptosis.
We have shown that carbon monoxide (CO) generated by heme oxygenase-1 (HO-1) protects endothelial cells (EC) from tumor necrosis alpha (TNF-alpha)-mediated apoptosis. This effect relies on the activation of p38 MAPK. We now demonstrate that HO-1/CO requires the activation of the transcription factor NF-kappaB to exert this anti-apoptotic effect. Our data suggest that EC have basal levels of NF-kappaB activity that sustain the expression of NF-kappaB-dependent anti-apoptotic genes required to support the anti-apoptotic effect of HO-1/CO. Over-expression of the inhibitor of NF-kappaB alpha (IkappaBalpha) suppresses the anti-apoptotic action of HO-1/CO. Reconstitution of NF-kappaB activity, by co-expression of IkappaBalpha with different members of the NF-kappaB family, i.e. p65/RelA or p65/RelA plus c-Rel, restores the anti-apoptotic effect of HO-1/CO. Expression of the NF-kappaB family members p65/RelA or p65/RelA with p50 or c-Rel up-regulates the expression of the anti-apoptotic genes A1, A20, c-IAP2, and manganese superoxide dismutase (MnSOD). Inhibition of NF-kappaB activity by over-expression of IkappaBalpha suppresses the expression of some of these anti-apoptotic genes, i.e. c-IAP2. Under inhibition of NF-kappaB, co-expression of some of these anti-apoptotic genes, i.e. c-IAP2 and A1, restores the anti-apoptotic action of HO-1/CO, whereas expression of A20 or MnSOD cannot. The ability of c-IAP2 and/or A1 to restore the anti-apoptotic action of HO-1/CO is abolished when p38 MAPK activation is blocked by over-expression of a p38 MAPK dominant negative mutant. In conclusion, we demonstrate that HO-1/CO cooperates with NF-kappaB-dependent anti-apoptotic genes, i.e. c-IAP2 and A1, to protect EC from TNF-alpha-mediated apoptosis. This effect is dependent on the ability of HO-1/CO to activate the p38 MAPK signal transduction pathway.
Brouard
Sophie
S
Immunobiology Research Center, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
Berberat
Pascal O
PO
Tobiasch
Edda
E
Seldon
Mark P
MP
Bach
Fritz H
FH
Soares
Miguel P
MP
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002248:Carbon Monoxide / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects*; D004789:Enzyme Activation; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D020672:I-kappa B Proteins; D008565:Membrane Proteins; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D008565:Membrane Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D002248:Carbon Monoxide; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse; D013482:Superoxide Dismutase; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases