Mitochondrial gene polymorphisms alter hepatic cellular energy metabolism and aggravate diet-induced non-alcoholic steatohepatitis

Torsten Schröder, David Kucharczyk, Florian Bär, René Pagel, Stefanie Derer, Sebastian Torben Jendrek, Annika Sünderhauf, Ann Kathrin Brethack, Misa Hirose, Steffen Möller, Axel Künstner, Julia Bischof, Imke Weyers, Jörg Heeren, Dirk Koczan, Sebastian Michael Schmid, Senad Divanovic, Daniel Aaron Giles, Jerzy Adamski, Klaus FellermannHendrik Lehnert, Jörg Köhl, Saleh Ibrahim, Christian Sina

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Objective: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is associated with an enhanced risk for liver and cardiovascular diseases and mortality. NAFLD can progress from simple hepatic steatosis to non-alcoholic steatohepatitis (NASH). However, the mechanisms predisposing to this progression remain undefined. Notably, hepatic mitochondrial dysfunction is a common finding in patients with NASH. Due to a lack of appropriate experimental animal models, it has not been evaluated whether this mitochondrial dysfunction plays a causative role for the development of NASH. Methods: To determine the effect of a well-defined mitochondrial dysfunction on liver physiology at baseline and during dietary challenge, C57BL/6J-mtFVB/N mice were employed. This conplastic inbred strain has been previously reported to exhibit decreased mitochondrial respiration likely linked to a non-synonymous gene variation (nt7778 G/T) of the mitochondrial ATP synthase protein 8 (mt-ATP8). Results: At baseline conditions, C57BL/6J-mtFVB/N mice displayed hepatic mitochondrial dysfunction characterized by decreased ATP production and increased formation of reactive oxygen species (ROS). Moreover, genes affecting lipid metabolism were differentially expressed, hepatic triglyceride and cholesterol levels were changed in these animals, and various acyl-carnitines were altered, pointing towards an impaired mitochondrial carnitine shuttle. However, over a period of twelve months, no spontaneous hepatic steatosis or inflammation was observed. On the other hand, upon dietary challenge with either a methionine and choline deficient diet or a western-style diet, C57BL/6J-mtFVB/N mice developed aggravated steatohepatitis as characterized by lipid accumulation, ballooning of hepatocytes and infiltration of immune cells. Conclusions: We observed distinct metabolic alterations in mice with a mitochondrial polymorphism associated hepatic mitochondrial dysfunction. However, a second hit, such as dietary stress, was required to cause hepatic steatosis and inflammation. This study suggests a causative role of hepatic mitochondrial dysfunction in the development of experimental NASH.

Original languageBritish English
Pages (from-to)283-295
Number of pages13
JournalMolecular Metabolism
Volume5
Issue number4
DOIs
StatePublished - 1 Apr 2016

Keywords

  • Lipid metabolism
  • Mitochondrial dysfunction
  • Mitochondrial gene polymorphism
  • NAFLD
  • Steatohepatitis
  • TNFα

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