PDE5 Inhibition with Sildenafil Blocks Induction of Carboxylesteras3 and Reduces Cell Necrosis and Autophagy in Acute Alcohol‐Induced Injury in Heart

Abstract

Objective:Fatty Acid Ethyl Esters (FAEE) are esterified products of alcohol that can cause severe damage to tissue organs and are mediators of ethanol‐induced cytotoxic effects. The mechanism that underlie the onset, progression and severity of alcohol toxicity are poorly understood. Carboxylesterase3 (CES3) is an enzyme responsible for esterification of fatty acids and drugs. We hypothesized that CES3 may be involved in metabolizing alcohol and lead to cell injury.Methods and Results:Rat cardiac myoblast cells (H9C2) were treated with ethanol (100mM) or ethanol with sildenafil (1 µM) for 24hrs. Adult male 12‐14 weeks old FVB mice were randomized to receive saline (0.2 ml; i.p, n =3) or Alcohol (1.5 g/ BID; i.p, n=3) or alcohol with sildenafil (0.7mg/kg/day; i.p, n=3) for 3 days.Treatment of H9C2 cells with 100mM ethanol significantly increased the necrosis of cells (41.1 % vs 3.5 % control), whereas sildenafil treatment lowered cell death (17.9 % vs 41.1 % alcohol). CES‐3 protein level was increased 2 fold both in H9c2 cells and in acute ethanol treated mice. Moreover Beclin‐1, an inducer of autophagy was also significantly up‐ regulated upon alcohol treatment in H9C2 cells. Sildenafil treatment prevented the induction of CES3 both in H9C2 cells and in mice.ConclusionTherapeutic intervention using sildenafil can prevent the formation of esters by decreasing CES3 in heart and thus can decrease necrosis and autophagy. Our data reports a novel role of CES3 and a new mechanism in which sildenafil can protect heart from acute alcohol injury. This study was supported in part by grants from National Institutes of Health (HL51045, HL79424, HL118808 to RCK).