Azelnidipine, a new calcium channel blocker, inhibits endothelial inflammatory response by reducing intracellular levels of reactive oxygen species.
Oxidized low-density lipoprotein (ox-LDL) plays an important in the development of atherosclerosis by stimulating the production of reactive oxygen species in endothelial cells, and thereby up-regulating vascular cell adhesion molecule-1 (VCAM-1). The objectives of the present study were to determine the effects of azelnidipine, a new calcium channel blocker, on the expression of VCAM-1 induced by 7-ketocholesterol, components of ox-LDL, and tumor necrosis factor-alpha (TNF-alpha). The scavenging activities of azelnidipine against superoxide, hydroxyl, and carbon-centered radicals were determined by electron spin resonance assay. The levels of intracellular reactive oxygen species were determined fluorometrically with the use of dichlorodihydrofluorescein diacetate (H(2)DCF-DA). Human aortic endothelial cells and U937 were used as endothelial cells and monocytic cells, respectively. The surface expression and mRNA levels of VCAM-1 were determined by enzyme immunoassay and RT-PCR performed on endothelial cell monolayers stimulated with 7-ketocholesterol or TNF-alpha. The numbers of monocytic cells adhering on the stimulated endothelial cells were counted in the microscopic fields. Translocation of p65 protein to the nucleus was estimated by fluorescence microscopy. Azelnidipine, but not nifedipine, reduced the signal intensity of 1,1-diphenyl-2-picrylhydrazyl radicals. Azelnidipine scavenged hydroxyl radicals, but not superoxide radicals. Intracellular levels of reactive oxygen species and RelA (p65) nuclear translocation in stimulated endothelial cells were reduced by azelnidipine. Azelnidipine significantly inhibited the expression of protein and mRNA of VCAM-1, and prevented the U937 cell adhesion to endothelial cells treated with 7-ketocholesterol or TNF-alpha. These results suggest that azelnidipine works as an anti-atherogenic agent by inhibiting the reactive oxygen species-dependent expression of VCAM-1 induced by 7-ketocholesterol and TNF-alpha.
Naito
Yuji
Y
Department of Medical Proteomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan. ynaito@koto.kpu-m.ac.jp
Shimozawa
Makoto
M
Manabe
Hikori
H
Nakabe
Nami
N
Katada
Kazuhiro
K
Kokura
Satoshi
S
Yoshida
Norimasa
N
Ichikawa
Hiroshi
H
Kon
Tatsuya
T
Yoshikawa
Toshikazu
T
D001011:Aorta / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D001713:Biphenyl Compounds; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D002448:Cell Adhesion / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003497:Cyclic N-Oxides; D004095:Dihydropyridines / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005452:Fluoresceins; D016166:Free Radical Scavengers / Q000494:pharmacology* / Q000627:therapeutic use; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006834:Hydrazines; D007202:Indicators and Reagents; D007249:Inflammation / Q000378:metabolism / Q000517:prevention & control*; D007653:Ketocholesterols / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology; D010851:Picrates; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020298:U937 Cells; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
C110400:2',7'-dichlorodihydrofluorescein diacetate; D001713:Biphenyl Compounds; D002121:Calcium Channel Blockers; D003497:Cyclic N-Oxides; D004095:Dihydropyridines; D005452:Fluoresceins; D016166:Free Radical Scavengers; D006834:Hydrazines; D007202:Indicators and Reagents; D007653:Ketocholesterols; D052002:NF-kappa B p50 Subunit; C489548:NFKB1 protein, human; D010851:Picrates; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D001383:Azetidinecarboxylic Acid; C017245:5,5-dimethyl-1-pyrroline-1-oxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D009543:Nifedipine; C003001:7-ketocholesterol; C061679:azelnidipine