Anti-inflammatory role of cilostazol in vascular smooth muscle cells in vitro and in vivo.
OBJECTIVE
Cilostazol is a selective inhibitor of phosphodiesterase 3, by which it increases intracellular cAMP and activates protein kinase A, thereby inhibiting platelet aggregation and inducing peripheral vasodilation. We investigated whether cilostazol might prevent nuclear factor (NF)-kappaB activation by activating AMP-activated protein kinase (AMPK) in vascular smooth muscle cells (VSMC).


RESULTS
Cilostazol was observed to activate AMPK, as well as its downstream target, acetyl-CoA carboxylase, in rat VSMC. Phosphorylation of AMPK with cilostazol was not affected by co-treatment with an adenylate cyclase inhibitor, SQ 22536. Furthermore, a cell-permeable cyclic AMP analog, pCTP-cAMP, did not influence cilostazol-induced AMPK phosphorylation. These findings suggest that cilostazol-induced AMPK activation occurs through a signalling pathway independent of cyclic AMP. Cilostazol dose-dependently inhibited LPS-induced NF-kappaB activation in the present study. It was also observed to inhibit LPS-induced iNOS gene promoter activity and iNOS gene expression, resulting in markedly reduced NO production. An AMPK inhibitor compound C or siRNA for AMPK attenuated the observed cilostazol-induced inhibition of NF-kappaB activation by LPS. Ingestion of cilostazol inhibited NF-kappaB activation, as well as the induction of iNOS mRNA and protein expression, within the aortas of LPS-treated rats.


CONCLUSIONS
In light of these findings, we suggest that cilostazol might attenuate cytokine-induced expression of the iNOS gene by inhibiting NF-kappaB following AMPK activation in VSMC.
Aoki
Chie
C
Department of Endocrinology and Metabolism, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
Hattori
Yoshiyuki
Y
Tomizawa
Atsuko
A
Jojima
Teruo
T
Kasai
Kikuo
K
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D000077407:Cilostazol; D017931:DNA Primers; D004789:Enzyme Activation; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D013777:Tetrazoles / Q000494:pharmacology*
D017931:DNA Primers; D016328:NF-kappa B; D010726:Phosphodiesterase Inhibitors; D013777:Tetrazoles; D052247:Nitric Oxide Synthase Type II; D055372:AMP-Activated Protein Kinases; D000077407:Cilostazol