Open AccessShort Term Feeding of a High Fat Diet Exerts an Additive Effect on Hepatocellular Damage and Steatosis in Liver-Specific PTEN Knockout Mice
Author(s) -
Colin T. Shearn,
Kelly E. Mercer,
David J. Orlicky,
Leah Hennings,
Rebecca L. Smathers-McCullough,
Bangyan L. Stiles,
Martin J. J. Ronis,
Dennis R. Petersen
Publication year - 2014
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0096553
Subject(s) - lipogenesis , steatosis , endocrinology , medicine , pten , cd36 , downregulation and upregulation , protein kinase b , fatty liver , beta oxidation , chemistry , fatty acid synthase , oxidative stress , biology , lipid metabolism , pi3k/akt/mtor pathway , apoptosis , biochemistry , metabolism , receptor , disease , gene
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 (PTEN f/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 PTEN f/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 PTEN f/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 PTEN f/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.