RT Journal Article T1 Endoplasmic Reticulum Stress-Induced Upregulation of STARD1 Promotes Acetaminophen-Induced Acute Liver Failure. A1 Torres, Sandra A1 Baulies, Anna A1 Insausti-Urkia, Naroa A1 Alarcón-Vila, Cristina A1 Fucho, Raquel A1 Solsona-Vilarrasa, Estel A1 Núñez, Susana A1 Robles, David A1 Ribas, Vicent A1 Wakefield, Leslie A1 Grompe, Markus A1 Lucena, M Isabel A1 Andrade, Raul J A1 Win, Sanda A1 Aung, Tin A A1 Kaplowitz, Neil A1 García-Ruiz, Carmen A1 Fernández-Checa, Jose C K1 APAP Toxicity K1 Lipid K1 Mouse Model K1 Signal Transduction AB Acetaminophen (APAP) overdose is a major cause of acute liver failure (ALF). Mitochondrial SH3BP5 (also called SAB) and phosphorylation of c-Jun N-terminal kinase (JNK) mediate the hepatotoxic effects of APAP. We investigated the involvement of steroidogenic acute regulatory protein (STARD1), a mitochondrial cholesterol transporter, in this process and sensitization by valproic acid (VPA), which depletes glutathione and stimulates steroidogenesis. Nonfasted C57BL/6J mice (control) and mice with liver-specific deletion of STARD1 (Stard1ΔHep), SAB (SabΔHep), or JNK1 and JNK2 (Jnk1+2ΔHep) were given VPA with or without APAP. Liver tissues were collected and analyzed by histology and immunohistochemistry and for APAP metabolism, endoplasmic reticulum (ER) stress, and mitochondrial function. Adult human hepatocytes were transplanted into Fah-/-/Rag2-/-/Il2rg-/-/NOD (FRGN) mice to create mice with humanized livers. Administration of VPA before administration of APAP increased the severity of liver damage in control mice. The combination of VPA and APAP increased expression of CYP2E1, formation of NAPQI-protein adducts, and depletion of glutathione from liver tissues of control mice, resulting in ER stress and the upregulation of STARD1. Livers from control mice given VPA and APAP accumulated cholesterol in the mitochondria and had sustained mitochondrial depletion of glutathione and mitochondrial dysfunction. Inhibition of ER stress, by administration of tauroursodeoxycholic acid to control mice, prevented upregulation of STARD1 in liver and protected the mice from hepatoxicity following administration of VPA and APAP. Administration of N-acetylcysteine to control mice prevented VPA- and APAP-induced ER stress and liver injury. Stard1ΔHep mice were resistant to induction of ALF by VPA and APAP, despite increased mitochondrial levels of glutathione and phosphorylated JNK; we made similar observations in fasted Stard1ΔHep mice given APAP alone. SabΔHep mice or Jnk1+2ΔHep mice did not develop ALF following administration of VPA and APAP. The ability of VPA to increase the severity of APAP-induced liver damage was observed in FRGN mice with humanized liver. In studies of mice, we found that upregulation of STARD1 following ER stress mediates APAP hepatoxicity via SH3BP5 and phosphorylation of JNK1 and JNK2. YR 2019 FD 2019-04-25 LK http://hdl.handle.net/10668/13884 UL http://hdl.handle.net/10668/13884 LA en DS RISalud RD Apr 16, 2025