PT  - JOURNAL ARTICLE
AU  - Park, So Youn
AU  - Lee, Jeong Hyun
AU  - Kim, Chi Dae
AU  - Lee, Won Suk
AU  - Park, Won Sun
AU  - Han, Jin
AU  - Kwak, Yong-Geun
AU  - Kim, Ki Young
AU  - Hong, Ki Whan
TI  - Cilostazol Suppresses Superoxide Production and Expression of Adhesion Molecules in Human Endothelial Cells via Mediation of cAMP-Dependent Protein Kinase-Mediated Maxi-K Channel Activation
AID  - 10.1124/jpet.105.098509
DP  - 2006 Jun 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 1238--1245
VI  - 317
IP  - 3
4099  - http://jpet.aspetjournals.org/content/317/3/1238.short
4100  - http://jpet.aspetjournals.org/content/317/3/1238.full
SO  - J Pharmacol Exp Ther2006 Jun 01; 317
AB  - This study shows whether increased intracellular cAMP level by cilostazol is directly coupled to its maxi-K channel activation in human endothelial cells. Cilostazol (1 μM) increased the K+ currents in the human endothelial cells by activating maxi-K channels, which was abolished by iberiotoxin (100 nM), a maxi-K channel blocker. On incubation of human coronary artery endothelial cells with tumor necrosis factor-α (TNF-α) (50 ng/ml), monocyte adhesion significantly increased with increased superoxide generation and expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) accompanied by increased degradation of inhibitory κBα in cytoplasm and activation of nuclear factor-κB p65 in nucleus. All these variables were significantly suppressed by cilostazol (10 μM), which was antagonized by iberiotoxin (1 μM) and (9R,10S,12S)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-l] [1,6]benzodiazocine-10-carboxylic acid hexyl ester (KT 5720) (300 nM, cAMP-dependent protein kinase inhibitor), but not by (9S,10R,12R)-2,3,9,10,11,12-hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindo-lo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-I][1,6]benzodiazocine-10-carboxylic acid methyl ester (KT 5823) (300 nM, cGMP-dependent protein kinase inhibitor). In the human endothelial cells transfected with siRNA-targeting maxi-K channels, cilostazol did not suppress the superoxide generation, VCAM-1 and MCP-1 expressions, and monocyte adhesion as contrasted with the wild-type cells. These findings were similarly evident with (3S)-(+)-(5-chloro-2-methoxyphenyl)-1,3-dihydro-3-fluoro-6-(trifluoromethyl)-2H-indole-2-one (BMS-204352), a maxi-K channel opener, and forskolin and dibutyryl cAMP. In conclusion, increased cAMP level by cilostazol is directly coupled to its maxi-K channel opening action via protein kinase activation in human endothelial cells, thereby suppressing TNF-α–stimulated superoxide production and expression of adhesion molecules. The American Society for Pharmacology and Experimental Therapeutics