Cilostazol inhibits HMGB1 release in LPS-activated RAW 264.7 cells and increases the survival of septic mice

Introduction: Inflammation and coagulation play important roles in the pathogenesis of sepsis. Anticoagulants with anti-inflammatory action draw attention as therapeutic agent in sepsis. Objective: Whether cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy]-3,4-dihydro-2-(1H)-quinolinone), anticoagulant, protects mice against sepsis and underlying mechanism(s) were investigated. Methods: Induction of heme oxygenase (HO)-1 protein, phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) luciferase activity, and release of high mobility group box 1 (HMGB1) were analyzed using signal inhibitors and transfection techniques. Survival and organ damage were compared in septic mice with and without cilostazol. Results: In RAW264.7 cells, cilostazol increased phosphorylation of AMPK which was followed by HO-1 induction. Lipopolysaccharide (LPS)-activated HMGB1 release was reduced by cilostazol which was reversed by both SB203580 and silencing of HO-1 orAMPK RNA. Interestingly, silencing AMPK reduced HO-1 expression, whereas silencing HO-1 did not affect p-AMPK by cilostazol. Both compound C and zinc protoporphyrin IX (ZnPPIX) antagonized inhibitory effect of HMGB1 by cilostazol. Cilostazol inhibited NF-kappa B luciferase activity which was antagonized by SB203580. Finally, the administration of cilostazol increased the survival of endotoxemic mice but failed to do so when co-treated with rHMGB1. Cilostazol reduced circulating HMGB1, plasminogen activator inhibitor-1 (PAI-1) levels, organ damages and protein expression of PAI-1 in lung tissues of CLP-septic mice, which were antagonized by ZnPPIX. Conclusion: These findings suggest that HMGB1 can be a target molecule of cilostazol by 1) AMPK activation, and 2) induction of HO-1 by p38 MAPK and AMPK. Therefore, cilostazol may be useful for treatment of sepsis. (C) 2015 Elsevier Ltd. All rights reserved.