title: Liver-specific deletion of augmenter of liver regeneration accelerates development of steatohepatitis and hepatocellular carcinoma in mice.
abstract: OBJECTIVE
  Augmenter of liver regeneration (ALR, encoded by GFER) is a widely distributed pleiotropic protein originally identified as a hepatic growth factor. However, little is known about its roles in hepatic physiology and pathology. We created mice with liver-specific deletion of ALR to study its function.
  
  
  METHODS
  We developed mice with liver-specific deletion of ALR (ALR-L-KO) using the albumin-Cre/LoxP system. Liver tissues were collected from ALR-L-KO mice and ALR(floxed/floxed) mice (controls) and analyzed by histology, reverse-transcription polymerase chain reaction, immunohistochemistry, electron microscopy, and techniques to measure fibrosis and lipids. Liver tissues from patients with and without advanced liver disease were determined by immunoblot analysis.
  
  
  RESULTS
  Two weeks after birth, livers of ALR-L-KO mice contained low levels of ALR and adenosine triphosphate (ATP); they had reduced mitochondrial respiratory function and increased oxidative stress, compared with livers from control mice, and had excessive steatosis, and hepatocyte apoptosis. Levels of carbamyl-palmitoyl transferase 1a and ATP synthase subunit ATP5G1 were reduced in livers of ALR-L-KO mice, indicating defects in mitochondrial fatty acid transport and ATP synthesis. Electron microscopy showed mitochondrial swelling with abnormalities in shapes and numbers of cristae. From weeks 2-4 after birth, levels of steatosis and apoptosis decreased in ALR-L-KO mice, and numbers of ALR-expressing cells increased, along with ATP levels. However, at weeks 4-8 after birth, livers became inflamed, with hepatocellular necrosis, ductular proliferation, and fibrosis; hepatocellular carcinoma developed by 1 year after birth in nearly 60% of the mice. Hepatic levels of ALR were also low in ob/ob mice and alcohol-fed mice with liver steatosis, compared with controls. Levels of ALR were lower in liver tissues from patients with advanced alcoholic liver disease and nonalcoholic steatohepatitis than in control liver tissues.
  
  
  CONCLUSIONS
  We developed mice with liver-specific deletion of ALR, and showed that it is required for mitochondrial function and lipid homeostasis in the liver. ALR-L-KO mice provide a useful model for investigating the pathogenesis of steatohepatitis and its complications.
authors.affiliation: Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati VA Medical Center, Cincinnati, Ohio; Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pennsylvania. Electronic address: gandhicr@ucmail.uc.edu.
authors.forename: Chandrashekhar R
authors.initials: CR
authors.lastname: Gandhi
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pennsylvania.
authors.forename: J Richard
authors.initials: JR
authors.lastname: Chaillet
authors.affiliation: Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pennsylvania; Department of Pathology, University of Pittsburgh, Pennsylvania.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Nalesnik
authors.affiliation: Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati VA Medical Center, Cincinnati, Ohio.
authors.forename: Anil
authors.initials: A
authors.lastname: Dangi
authors.affiliation: Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pennsylvania; Department of Pathology, University of Pittsburgh, Pennsylvania.
authors.forename: A Jake
authors.initials: AJ
authors.lastname: Demetris
authors.affiliation: School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Robert
authors.initials: R
authors.lastname: Ferrell
authors.affiliation: Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana.
authors.forename: Tong
authors.initials: T
authors.lastname: Wu
authors.affiliation: Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Senad
authors.initials: S
authors.lastname: Divanovic
authors.affiliation: Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
authors.forename: Traci
authors.initials: T
authors.lastname: Stankeiwicz
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pennsylvania.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Shaffer
authors.affiliation: Department of Cell Biology, University of Pittsburgh, Pennsylvania.
authors.forename: Donna B
authors.initials: DB
authors.lastname: Stolz
authors.affiliation: Department of Ophthalmology, University of Pittsburgh, Pennsylvania.
authors.forename: Stephen A K
authors.initials: SA
authors.lastname: Harvey
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Jiang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pennsylvania.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Starzl
mesh_terms: D000818:Animals; D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000209:etiology*; D003579:Cytochrome Reductases / Q000502:physiology; D005234:Fatty Liver / Q000209:etiology*; D006801:Humans; D050356:Lipid Metabolism; D008106:Liver Cirrhosis, Experimental / Q000209:etiology; D008113:Liver Neoplasms / Q000209:etiology*; D008115:Liver Regeneration / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000502:physiology; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000502:physiology*
chemical_list: D003579:Cytochrome Reductases; C500897:GFER protein, human; D050862:Oxidoreductases Acting on Sulfur Group Donors; C551231:GFER protein, mouse
keywords: ALD; Augmenter of Liver Regeneration; Mouse Model; NASH