studies

240A AASLD ABSTRACTS HEPATOLOGY, October, 2015
65
Akt-mediated FoxO1 inhibition is required for liver
regeneration after partial hepatectomy in mice
Montserrat Pauta 1,3 , Noemi Rotllan 4,5 , Ana Fernandez-Hernando 6 ,
Cedric Langhi 7 , Jordi Ribera 1,2 , Loreto Boix 8,2 , Jordi Bruix 8,2 ,
Wladimiro Jiménez 1,9 , Yajaira Suarez 4,5 , David A. Ford 7 , Angel
Baldan 7 , Morris J. Birnbaum 10 , Manuel Morales-Ruiz 1,2 , Carlos
Fernandez-Hernando 4,5 ; 1 Biochemistry and Molecular Genetics,
Hospital Clinic, Barcelona, Spain; 2 IDIBAPS, CIBERehd, Barcelona,
Spain; 3 IDIBAPS, Barcelona, Spain; 4 Vascular Biology and Therapeutics
Program, Yale University School of Medicine, New Haven,
CT; 5 Integrative Cell Signaling and Neurobiology of Metabolism
Program, Section of Comparative Medicine and Department of
Pathology, Yale University School of Medicine, New Haven, CT;
6 Departments of Medicine and Cell Biology, Leon H. Charney
Division of Cardiology, New York University School of Medicine,
New York, NY; 7 Edward A. Doisy Department of Biochemistry &
Molecular Biology, and Center for Cardiovascular Research, Saint
Louis University, Saint Louis, MO; 8 Barcelona Clinic Liver Cancer
(BCLC) Group, Liver Unit, Hospital Clinic of Barcelona, University
of Barcelona, Barcelona, Spain; 9 Department of Physiological
Sciences I, IDIBAPS, CIBERehd, University of Barcelona School of
Medicine, Barcelona, Spain; 10 Institute for Diabetes, Obesity, and
Metabolism, Perelman School of Medicine, University of Pennsylvania,
Philadelphia, PA
Introduction and aim: Understanding the hepatic regenerative
process has clinical interest since the effectiveness of many
treatments for chronic liver diseases is conditioned by an efficient
liver regeneration. Experimental evidence points to the
need of a temporal coordination between cytokines, growth
factors and metabolic signaling pathways to enable successful
liver regeneration. One intracellular mediator that acts as a
signal integration node for these processes is the serine-threonine
kinase Akt, being Akt1 and Akt2 the most abundant
isoforms expressed in the liver. Therefore, the aim of this study
was to demonstrate whether Akt, globally or through any of
its isoforms, has a significant role in liver regeneration. Methods:
Two-thirds partial hepatectomy (PH) was performed in
eight-old-week male Akt1 -/- , Akt2 -/- , Akt1 loxP/loxP , Akt2 loxP/loxP ,
FoxO1 loxP/loxP and wild-type (WT) mice. In addition, we generated
the Akt1 loxP/loxP ;Akt2 loxP/loxP ;FoxO1 loxP/loxP mice (TLKO)
by crossing the Akt1 loxP/loxP ;Akt2 loxP/loxP mice (DLKO) with the
FoxO1 loxP/loxP mice. The liver specific DLKO and TLKO deficient
mice were generated by treating the floxed mice with adeno-associated
virus encoding for the Cre-recombinase driven
by the Alpha-Fetoprotein promoter. Mice from each group
were sacrificed at various times post-hepatectomy (0 days, 2d,
4d and 7d; n = 5-10) for evaluating biochemical and liver
function parameters. Results: The hepatic deficiency of single
Akt1 or Akt2 does not influence liver regeneration after PH.
However, DLKO mice show impaired liver regeneration and
a significant increase mortality (compared with WT, Akt1 -/-
and Akt2 -/- mice; P10-fold;
p50%) by 15min,
and only approached basal levels by 96h post-PH. TMX-DTG
mice (with reduced Hh signaling) accumulated 50% fewer
Gli2+ cells, and 2-3 fold less Gli1 and Gli2 mRNA (p