Antioxidants inhibit monocyte adhesion by suppressing nuclear factor-kappa B mobilization and induction of vascular cell adhesion molecule-1 in endothelial cells stimulated to generate radicals.
Cell adhesion to endothelial cells stimulated by tumor necrosis factor-alpha (TNF) is due to induction of surface receptors, such as vascular cell adhesion molecule-1 (VCAM-1). The antioxidant pyrrolidine dithiocarbamate (PDTC) specifically inhibits activation of nuclear factor-kappa B (NF-kappa B). Since kappa B motifs are present in VCAM-1 and intercellular adhesion molecule-1 (ICAM-1) promoters, we used PDTC to study the regulatory mechanisms of VCAM-1 and ICAM-1 induction and subsequent monocyte adhesion in TNF-treated human umbilical vein endothelial cells (HUVECs). PDTC or N-acetylcysteine dose dependently reduced TNF-induced VCAM-1 but not ICAM-1 surface protein (also in human umbilical arterial endothelial cells) and mRNA expression (by 70% at 100 mumol/L PDTC) in HUVECs as assessed by flow cytometry and polymerase chain reaction. Gel-shift analysis in HUVECs demonstrated that PDTC prevented NF-kappa B mobilization by TNF, suggesting that only VCAM-1 induction was controlled by NF-kappa B. Since HUVECs released superoxide anions in response to TNF, and H2O2 induces VCAM-1, PDTC may act as a radical scavenger. Although ICAM-1 induction was unaffected, inhibitors of NADPH oxidase (apocynin) or cytochrome P-450 (SKF525a) suppressed VCAM-1 induction by TNF, revealing that several radical-generating systems are involved in its regulation. PDTC, apocynin, or SKF525a decreased adhesion of monocytic U937 cells to TNF-treated HUVECs (by 75% at 100 mumol/L PDTC). Inhibition by anti-VCAM-1 monoclonal antibody 1G11 indicated that U937 adhesion was VCAM-1 dependent and suppression by antioxidants was due to reduced VCAM-1 induction.(ABSTRACT TRUNCATED AT 250 WORDS)
Weber
C
C
Institut für Prophylaxe der Kreislaufkrankheiten, München, Germany.
Erl
W
W
Pietsch
A
A
Ströbel
M
M
Ziegler-Heitbrock
H W
HW
Weber
P C
PC
D000111:Acetylcysteine / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D001483:Base Sequence; D001692:Biological Transport / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects* / Q000502:physiology; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015345:Oligonucleotide Probes / Q000235:genetics; D016133:Polymerase Chain Reaction; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013859:Thiocarbamates / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1
D000975:Antioxidants; D015815:Cell Adhesion Molecules; D016328:NF-kappa B; D015345:Oligonucleotide Probes; D011759:Pyrrolidines; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D013859:Thiocarbamates; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; C020972:pyrrolidine dithiocarbamic acid; D000111:Acetylcysteine