CD40 ligation triggers COX-2 expression in endothelial cells: evidence that CD40-mediated IL-6 synthesis is COX-2-dependent.
OBJECTIVE
To investigate whether CD40-CD154 interactions on HUVEC can trigger COX-2 synthesis as well as PGE2 and PGI2 secretion in vitro and explore whether the CD40-triggered prostanoids provide costimulatory signals for IL-6 secretion in this cell type.


METHODS
COX-2 protein expression was examined in HUVEC using Western blot analysis. ELISAs were employed to assess PGE2, PGI2 and IL-6 synthesis.


RESULTS
We found that COX-2 expression is upregulated when HUVEC are cultured with CD154+ D1.1 cells but not CD154- B2.7 cells. This effect was specifically inhibited by anti-CD154 mAb, and was amplified by the presence of IFNgamma. Analysis of cell supernatants showed a concomitant rise in PGE2 and PGI2 secretion triggered by CD154+ D1.1 cells, or rsCD154. Use of selective (NS-398) and non-selective (ibuprofen) COX-2 inhibitors effectively inhibited prostanoid synthesis triggered by CD40 ligation. Reduction in prostanoid levels by NS-398 was accompanied by a reduction in IL-6 secretion levels triggered by CD40 ligation. Furthermore, exogenously added PGE2 triggered a dose-dependent IL-6 secretion, which was unaffected by NS-398.


CONCLUSIONS
These studies demonstrate that CD40 ligation upregulates HUVEC COX-2 expression and function. Moreover, the data strongly suggest that CD154-induced IL-6 secretion in HUVEC is dependent on COX-2 activity.
Dongari-Bagtzoglou
A I
AI
University of Connecticut, School of Dental Medicine, 263 Farmington Ave, Farmington, CT 06030-1710, USA. adongari@uchc.edu
Thienel
U
U
Yellin
M J
MJ
D015153:Blotting, Western; D019013:CD40 Antigens / Q000494:pharmacology*; D023201:CD40 Ligand / Q000494:pharmacology; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis; D015232:Dinoprostone / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D007527:Isoenzymes / Q000096:biosynthesis*; D008565:Membrane Proteins; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011453:Prostaglandins / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology
D019013:CD40 Antigens; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D016207:Cytokines; D015850:Interleukin-6; D007527:Isoenzymes; D008565:Membrane Proteins; D010726:Phosphodiesterase Inhibitors; D011453:Prostaglandins; D023201:CD40 Ligand; D007371:Interferon-gamma; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone