Cilostazol activates AMP-activated protein kinase and restores endothelial function in diabetes.
BACKGROUND
Endothelial dysfunction plays a key role in atherogenesis. We investigated whether AMP-activated protein kinase (AMPK) activity is a downstream mediator of the beneficial effects of cilostazol on vascular endothelial cells and whether cilostazol might reverse endothelial dysfunction in diabetic rats.


RESULTS
Treatment of human umbilical vein endothelial cells (HUVECs) with cilostazol resulted in time-dependent activation of AMPK, as monitored by phosphorylation of AMPK and its down-stream target, acetyl-CoA carboxylase (ACC). Activation of AMPK by cilostazol was through signaling pathway independent of cyclic AMP and caused phosphorylation of endothelial nitric oxide synthase (eNOS), leading to increased production of nitric oxide (NO), while inhibiting cytokine-induced nuclear factor-kappaB (NF-kappaB) activation, leading to suppression of VCAM-1 gene expression. Significantly reduced eNOS activity and NO production in response to cilostazol and attenuation of cilostazol-induced inhibition of NF-kappaB activation were observed in cells treated with AMPK siRNA. We also demonstrated that administration of cilostazol to diabetic rats significantly restored endothelium-dependent vasodilation. Furthermore, treatment of diabetic rats with cilostazol increased tetrahydrobiopterin (BH4) levels in the aorta. Thus, recovery of BH4 following administration of cilostazol might also contribute to restoration of endothelial function in diabetic rats.


CONCLUSIONS
Our findings suggest that the beneficial effects of cilostazol on endothelial function may be due to AMPK activation. Restoration of endothelial dysfunction in diabetic rats by cilostazol is at least partly attributed to amelioration of biopterin metabolism in the aorta.
Suzuki
Kunihiro
K
Department of Endocrinology and Metabolism, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
Uchida
Kohsuke
K
Nakanishi
Nobuo
N
Hattori
Yoshiyuki
Y
D055372:AMP-Activated Protein Kinases; D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D000077407:Cilostazol; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D018450:Disease Progression; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008297:Male; D051379:Mice; D009097:Multienzyme Complexes / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020318:Rats, Long-Evans; D013777:Tetrazoles / Q000494:pharmacology*; D014471:Umbilical Veins / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D001786:Blood Glucose; D009097:Multienzyme Complexes; D016328:NF-kappa B; D012333:RNA, Messenger; D013777:Tetrazoles; D019010:Vascular Cell Adhesion Molecule-1; D014665:Vasodilator Agents; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D000077407:Cilostazol