Apolipoprotein D Transgenic Mice Develop Hepatic Steatosis through Activation of PPAR? and Fatty Acid Uptake

Labrie, Marilyne; Lalonde, Simon; Najyb, Ouafa; Thiery, Maxime; Daneault, Caroline; Des Rosiers, Chrisitne; Rassart, Eric; Mounier, Catherine

We previously demonstrated that the mRNA levels of SREBP-1c and FAS were increased in the liver of H-apoD Tg compared to WT mice [15] . Since elevated lipogenesis has also been associated with hepatic steatosis, we evaluated the expression levels and the activity of several other key proteins involved in hepatic lipogenesis. We showed that the AMPK expression was increased by 1.82-fold in the liver of Tg mice. Its phosphorylation on Thr172 residue was also increased (2.63 fold), but the AMPK activity was unaffected as evaluated by the ratio of P-AMPα/AMPKα (Fig 4A) . As a consequence of increased AMPKα phosphorylation in Tg mice, one of the AMPKα target proteins, ACC displayed higher phosphorylation levels on Ser79 (1.7 fold, measured by the ratio P-ACC/ACC) suggesting a reduced activity of the first lipogenic enzyme (Fig 4B) . On the other hand, a significant increase in FAS protein expression was observed (1.97-fold) complementing our previous observation at the mRNA level [15] ( Fig 4C) . However, the mRNA expression of ACC, SCD1, DGAT and LXRα remained unaffected in the liver of H-apoD Tg mice compared to WT ( Fig 4D) .