Cilostazol protects hepatocytes against alcohol-induced apoptosis via activation of AMPK pathway

Abstract

Alcoholic liver disease (ALD) is a worldwide health problem and hepatocyte apoptosis has been associated with the development/progression of ALD. However, no definite effective pharmacotherapy for ALD is currently available. Cilostazol, a selective type III phosphodiesterase inhibitor has been shown to protect hepatocytes from ethanol-induced apoptosis. In the present study, the underlying mechanisms for the protective effects of cilostazol were examined. Primary rat hepatocytes were treated with ethanol in the presence or absence of cilostazol. Cell viability and intracellular cAMP were measured. Apoptosis was detected by Hoechst staining, TUNEL assay, and caspase-3 activity assay. The roles of cAMP and AMP-activated protein kinase (AMPK) pathways in the action of CTZ were explored using pharmacological inhibitors and siRNAs. Liver from mice received ethanol (5 g/kg body weight) by oral gavage following cilostazol treatment intraperitoneally was obtained for measurement of apoptosis and activation of AMPK pathway. Cilostazol inhibited ethanol-induced hepatocyte apoptosis and potentiated the increases in cAMP level induced by forskolin. However, the anti-apoptotic effect of cilostazol was not reversed by an inhibitor of adenylyl cyclase. Interestingly, cilostazol activated AMPK and increased the level of LC3-II, a marker of autophagy. The inhibition of AMPK abolished the effects of cilostazol on LC3-II expression and apoptosis. Moreover, the inhibition of LKB1 and CaMKK2, upstream kinases of AMPK, dampened cilostazol-inhibited apoptosis as well as AMPK activation. In conclusion, cilostazol protected hepatocytes from apoptosis induced by ethanol mainly via AMPK pathway which is regulated by both LKB1 and CaMKK2. Our results suggest that cilostazol may have potential as a promising therapeutic drug for treatment of ALD.

cAMP Signaling in Pathobiology of Alcohol Associated Liver Disease

“…The beneficial effect of cAMP signaling via activation of adenylate cyclase (AC) and the PDE3 inhibitor, Cilostazol, on liver injury has also been demonstrated in both in vivo and in vitro ALD models [ 124 , 125 , 126 ]. Treatment of ethanol-fed rats for the last four weeks of an eight-week study with 14-deoxyandrographolide (14-DAG) attenuated ethanol-induced hepatic apoptosis, oxidative stress and lipid peroxidation via activating AC [ 126 ].…”

“…Cilostazol decreased ethanol-induced oxidative stress and prevented mitochondrial pathway-mediated apoptosis in hepatocytes [ 124 ]. A later study recapitulated the anti-apoptotic effect of Cilostazol in ethanol-treated primary rat hepatocytes [ 125 ]. However, the authors suggested that this effect was not mediated by cAMP but rather by AMPK activation by Cilostazol.…”

Dipeptide YA is Responsible for the Positive Effect of Oyster Hydrolysates on Alcohol Metabolism in Single Ethanol Binge Rodent Models

“…In general, 100 mM is used to induce cell injury. However, even in reports, 100 mM EtOH induces cell death approximately 25% of the time [ 40 , 41 ]. These results are similar to our results.…”

Linking Dysregulated AMPK Signaling and ER Stress in Ethanol-Induced Liver Injury in Hepatic Alcohol Dehydrogenase Deficient Deer Mice

“…Activity of AMPK is also regulated by upstream kinases, LKB 1 and CaMKKβ, related to oxidative stress and ER stress, respectively. Inhibition of LKB1 and/or CaMKKβ could also deactivate AMPK [45]. Since AMPK activation plays a key role in maintaining the balance between anabolic and catabolic pathways for cellular homeostasis in response to metabolic stress, its deactivation could be involved in upregulation of lipogenesis and down regulation of fatty acid oxidation, resulting in lipid accumulation within the cell.…”