Nifedipine indirectly upregulates superoxide dismutase expression in endothelial cells via vascular smooth muscle cell-dependent pathways.
BACKGROUND
Calcium antagonists normalize endothelial dysfunction in many cardiovascular diseases. There is no known receptor, however, for calcium antagonists in endothelial cells (ECs). We hypothesized that vascular smooth muscle cells (VSMCs) are involved in the mechanism underlying the normalization of endothelial dysfunction by calcium antagonists.


RESULTS
Coculture studies with ECs and VSMCs were performed to determine whether VSMCs mediate modulation of endothelial superoxide dismutase (SOD) activity and expression induced by the calcium antagonist nifedipine. Nifedipine induced upregulation of SOD activity in rat aortic segments but had no effect on SOD expression or activity in ECs or VSMCs cultured individually. When ECs were cocultured with VSMCs, however, nifedipine upregulated SOD expression and activity in ECs. Nifedipine stimulated vascular endothelial growth factor (VEGF) production from VSMCs, and this stimulation of VEGF production was abolished by HOE-140, an antagonist of the bradykinin B(2) receptor. A neutralizing antibody against VEGF inhibited the upregulation of endothelial SOD by nifedipine. In addition, recombinant VEGF induced an increase in the levels of SOD expression in ECs, and supernatant derived from nifedipine-treated VSMCs enhanced NO production from ECs. This increase in NO production by the supernatant was inhibited by preincubation of ECs with SOD antisense oligodeoxyribonucleotides.


CONCLUSIONS
The calcium antagonist nifedipine indirectly upregulates endothelial SOD expression by stimulating VEGF production from adjacent VSMCs. This finding may provide further insight into the mechanism underlying the beneficial effects of calcium antagonists in cardiovascular diseases.
Department of Geriatric Medicine, Osaka University Medical School, Suita, Osaka, Japan. fukuo@geriat.med.osaka-u.ac.jp
Keisuke
K
Fukuo
Jin
J
Yang
Osamu
O
Yasuda
Masaki
M
Mogi
Toshimitsu
T
Suhara
Naoyuki
N
Sato
Takashi
T
Suzuki
Shigeto
S
Morimoto
Toshio
T
Ogihara
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000201:enzymology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002450:Cell Communication; D002478:Cells, Cultured; D018920:Coculture Techniques; D016228:Endothelial Growth Factors / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008222:Lymphokines / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology*; D009569:Nitric Oxide / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018002:Receptors, Bradykinin / Q000378:metabolism; D013482:Superoxide Dismutase / Q000096:biosynthesis*; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D002121:Calcium Channel Blockers; D016228:Endothelial Growth Factors; D008222:Lymphokines; D018002:Receptors, Bradykinin; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D009569:Nitric Oxide; D013482:Superoxide Dismutase; D009543:Nifedipine