title: Short term feeding of a high fat diet exerts an additive effect on hepatocellular damage and steatosis in liver-specific PTEN knockout mice.
abstract: BACKGROUND
  Hepatospecific deletion of PTEN results in constitutive activation of Akt and increased lipogenesis. In mice, the addition of a high fat diet (HFD) downregulates lipogenesis. The aim of this study was to determine the effects of a HFD on hepatocellular damage induced by deletion of PTEN.
  
  
  METHODS
  12 Week old male flox/flox hepatospecific PTEN mice (PTENf/f) or Alb-Cre controls were fed a HFD composed of 45% fat-derived calories (from corn oil) or a normal chow. Animals were then analyzed for hepatocellular damage, oxidative stress and expression of enzymes involved in fatty acid metabolism.
  
  
  RESULTS
  In the Alb-Cre animals, the addition of a HFD resulted in a significant increase in liver triglycerides and altered REDOX capacity as evidenced by increased GPX activity, decreased GST activity and decreased hepatic concentrations of GSSG. In addition, SCD2, ACLY and FASN were all downregulated by the addition of HFD. Furthermore, expression of PPARα and PPARα-dependent proteins Cyp4a and ACSL1 were upregulated. In the PTENf/f mice, HFD resulted in significant increased in ALT, serum triglycerides and decreased REDOX capacity. Although expression of fatty acid synthetic enzymes was elevated in the chow fed PTENf/f group, the addition of HFD resulted in SCD2, ACLY and FASN downregulation. Compared to the Alb-Cre HFD group, expression of PGC1α, PPARα and its downstream targets ACSL and Cyp4a were upregulated in PTENf/f mice.
  
  
  CONCLUSIONS
  These data suggest that during conditions of constitutive Akt activation and increased steatosis, the addition of a HFD enhances hepatocellular damage due to increased CD36 expression and altered REDOX status. In addition, this work indicates HFD-induced hepatocellular damage occurs in part, independently of Akt signaling.
authors.affiliation: Department of Pharmaceutical Sciences, University of Colorado Denver Anchutz Medical Campus, Aurora, Colorado, United States of America.
authors.forename: Colin T
authors.initials: CT
authors.lastname: Shearn
authors.affiliation: Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Mercer
authors.affiliation: Department of Pathology, University of Colorado Denver Anchutz Medical Campus, Aurora, Colorado, United States of America.
authors.forename: David J
authors.initials: DJ
authors.lastname: Orlicky
authors.affiliation: Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
authors.forename: Leah
authors.initials: L
authors.lastname: Hennings
authors.affiliation: Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio, United States of America.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Smathers-McCullough
authors.affiliation: Department of Pharmaceutical Sciences, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Bangyan L
authors.initials: BL
authors.lastname: Stiles
authors.affiliation: Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America; Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America.
authors.forename: Martin J J
authors.initials: MJ
authors.lastname: Ronis
authors.affiliation: Department of Pharmaceutical Sciences, University of Colorado Denver Anchutz Medical Campus, Aurora, Colorado, United States of America.
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Petersen
mesh_terms: D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism; D042926:Cytochrome P-450 CYP4A / Q000378:metabolism; D059305:Diet, High-Fat / Q000009:adverse effects*; D005234:Fatty Liver / Q000378:metabolism* / Q000473:pathology*; D008099:Liver / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress / Q000502:physiology; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*
chemical_list: D018955:CD36 Antigens; D042926:Cytochrome P-450 CYP4A; D051059:PTEN Phosphohydrolase