Nuclear factor-kappa B-independent anti-inflammatory action of salicylate in human endothelial cells: induction of heme oxygenase-1 by the c-jun N-terminal kinase/activator protein-1 pathway.
In contrast to aspirin, salicylate, its active metabolite, possesses profound anti-inflammatory properties without blocking cyclooxygenase. Inhibition of the transcription factor nuclear factor-kappaB (NF-kappaB) has been discussed to play a role in the anti-inflammatory profile of salicylate. However, NF-kappaB-independent effects of salicylate have been assumed but have up to now been poorly investigated. Therefore, the aim of the present study was to investigate NF-kappaB-independent anti-inflammatory mechanisms of salicylate in human umbilical vein endothelial cells using interleukin-4 (IL-4) as NF-kappaB-independent proinflammatory stimulus and P-selectin as inflammatory read-out parameter. Using quantitative real-time reverse transcription-polymerase chain reaction, we found that salicylate decreases IL-4-induced P-selectin expression. As judged by Western blot analysis, salicylate increased endothelial heme oxygenase-1 (HO-1) protein levels. Using both the HO-1 inhibitor tin(II) protoporphyrin IX and HO-1 antisense oligonucleotides, we causally linked the induction of HO-1 to the decrease of P-selectin. Moreover, we were interested in the signaling mechanisms leading to the up-regulation of HO-1 by salicylate. c-Jun NH2-terminal kinase (JNK) was found to be activated by salicylate, and we could causally link this activation to the induction of HO-1 by using the JNK inhibitor 1,9-pyrazoloanthrone. By applying activator protein-1 (AP-1) decoys, it was shown that the transcription factor AP-1 is crucially involved in the up-regulation of HO-1 downstream of JNK. In summary, our study introduces HO-1 as novel NF-kappaB-independent anti-inflammatory target of salicylate in human endothelial cells. Moreover, we elucidated the JNK/AP-1 pathway as crucial for the induction of HO-1 by salicylate.
Fürst
Robert
R
Department of Pharmacy, Pharmaceutical Biology, University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany. robert.fuerst@cup.uni-muenchen.de
Blumenthal
Signe B
SB
Kiemer
Alexandra K
AK
Zahler
Stefan
S
Vollmar
Angelika M
AM
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction / Q000187:drug effects / Q000502:physiology; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D048055:Mitogen-Activated Protein Kinase 8 / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism*; D012459:Salicylates / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000502:physiology*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016328:NF-kappa B; D012459:Salicylates; D018808:Transcription Factor AP-1; D051547:Heme Oxygenase-1; D048055:Mitogen-Activated Protein Kinase 8