The carbon monoxide releasing molecule (CORM-3) inhibits expression of vascular cell adhesion molecule-1 and E-selectin independently of haem oxygenase-1 expression.
OBJECTIVE
Although carbon monoxide (CO) can modulate inflammatory processes, the influence of CO on adhesion molecules is less clear. This might be due to the limited amount of CO generated by haem degradation. We therefore tested the ability of a CO releasing molecule (CORM-3), used in supra-physiological concentrations, to modulate the expression of vascular cell adhesion molecule (VCAM)-1 and E-selectin on endothelial cells and the mechanism(s) involved.


METHODS
Human umbilical vein endothelial cells (HUVECs) were stimulated with tumour necrosis factor (TNF)-alpha in the presence or absence of CORM-3. The influence of CORM-3 on VCAM-1 and E-selectin expression and the nuclear factor (NF)-kappaB pathway was assessed by flow cytometry, Western blotting and electrophoretic mobility shift assay.


RESULTS
CORM-3 inhibited the expression of VCAM-1 and E-selectin on TNF-alpha-stimulated HUVEC. VCAM-1 expression was also inhibited when CORM-3 was added 24 h after TNF-alpha stimulation or when TNF-alpha was removed. This was paralleled by deactivation of NF-kappaB and a reduction in VCAM-1 mRNA. Although TNF-alpha removal was more effective in this regard, VCAM-1 protein was down-regulated more rapidly when CORM-3 was added. CORM-3 induced haem oxygenase-1 (HO-1) in a dose- and time-dependent manner, mediated by the transcription factor, Nrf2. CORM-3 was still able to down-regulate VCAM-1 expression in HUVEC transfected with siRNA for HO-1 or Nrf2.


CONCLUSIONS
Down-regulation of VCAM and E-selectin expression induced by CORM-3 was independent of HO-1 up-regulation and was predominantly due to inhibition of sustained NF-kappaB activation.
Vth Medical Department, University Hospital Mannheim, Mannheim, Germany.
H
H
Song
C
C
Bergstrasser
N
N
Rafat
S
S
Höger
M
M
Schmidt
N
N
Endres
M
M
Goebeler
J L
JL
Hillebrands
R
R
Brigelius-Flohé
A
A
Banning
G
G
Beck
R
R
Loesel
B A
BA
Yard
D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002248:Carbon Monoxide / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D019040:E-Selectin / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009942:Organometallic Compounds / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; D019040:E-Selectin; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; C495635:NFE2L2 protein, human; D009942:Organometallic Compounds; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; C476530:tricarbonylchloro(glycinato)ruthenium(II); D002248:Carbon Monoxide; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1