However, APAP caused extensive oxidative DNA damage in cells, as indicated by gH2AX staining in nuclei as this website well as Comet assays for double-stranded DNA breaks. Memantine decreased this APAP-induced cellular DNA damage. These findings was in agreement with greater NMDAR expression in APAP-induced

ALF in mice along with less liver damage after memantine, including decreased gH2AX staining in liver of APAP-treated mice with memantine therapy. Conclusions: Expression of NMDARs contributed to DILI. Blockade of NMDARs by drugs improved APAP-induced DNA damage in cells and animals. This therapeutic benefit of NMDAR blockade was independent of associated events, such as KATP channel regulation, and offers further directions for controlling DILI in the clinical context. Disclosures: The following people have nothing to disclose: Nicole Pattamanuch, Preeti Viswa-nathan, Sylvia O. Suadicani, David C. Spray, Sanjeev Gupta PD0325901 clinical trial Acetaminophen (APAP) is a widely used pain reliever and a dose related hepatotoxin and a major cause of acute liver failure. Mitochondrial dysfunction, mitochondrial GSH (mGSH) depletion and JNK activation are well-recognized factors of APAP hepatotoxicity. Lysosomes are involved

in APAP-induced liver injury by a mechanism targeting mitochondria via lyso-somal iron mobilization. Moreover, autophagy protects against APAP hepatotoxicity. However, the role of lysosomal lipid storage in APAP hepatotoxicity has not been examined. As acid sphingomyelinase (ASMase) deficiency triggers a lysosomal storage disorder characterized by lysosomal sphingomyelin and cholesterol loading, our aim was to examine the role of ASMase in APAP-induced liver injury. Methods: H&E, TUNEL, ALT, GSH levels, protein adducts and JNK phosphorylation were examined after APAP treatment (300mg/Kg). Survival was

examined in fasted medchemexpress mice following a lethal dose of APAP (500 mg/kg). Cell viability was analysed in primary mouse hepatocytes (PMH) with Sytox Green. Mitophagy was analysed by confocal imaging in PMH expressing LAMP-GFP (lysosomal staining) and mtKeima (mitochondria staining) following 5mM APAP treatment. Moreover, PMH were treated with U18666A, an inhibitor of intracellular cholesterol transport, with or without 25-hydroxycholesterol (25-HC) to diminish lysosomal cholesterol content. Cathepsin B was inhibited with Ca-074-Me. Results: In vivo liver injury was higher and survival rate was lower in ASMase-/- mice treated with APAP. Similar findings were observed in PMH. However, protein adducts formation, JNK phosphorylation, mGSH depletion and connexin32 expression was similar in both types of mice.