Viral hepatitis and fatty liver disease: how an unwelcome guest makes pâté of the host.
HBV and HCV (hepatitis B and C viruses respectively) affect hundreds of millions of people globally, and are a major cause of chronic liver disease, including NAFLD (non-alcoholic fatty liver disease). Previous work on HCV-associated fatty liver disease has implicated two transcription factors that are important in lipid metabolism, SREBP1c (sterol-regulatory-element-binding protein 1c) and the LXRalpha (liver X receptor alpha). HBV-associated fatty liver disease has been less well-studied. New work from Kim and colleagues in this issue of the Biochemical Journal has provided new insight into how HBV causes fatty liver disease. Investigating HBV's so-called X gene product (HBx), they report that this viral protein directly binds to LXRalpha in the host liver cells to up-regulate the lipogenic transcription factor, SREBP1c. Also discussed in this commentary is another way that viruses such as HBV and HCV could induce SREBP1c-mediated lipogenesis, via the PI3K (phosphoinositide 3-kinase)-Akt signalling pathway.
Brown
Andrew J
AJ
BABS, School of Biotechnology and Biomolecular Sciences, Biosciences Building D26, University of New South Wales, Sydney, NSW 2052, Australia. aj.brown@unsw.edu.au
D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism; D005234:Fatty Liver / Q000201:enzymology / Q000209:etiology*; D006509:Hepatitis B / Q000150:complications* / Q000201:enzymology; D006511:Hepatitis B Antigens / Q000633:toxicity; D006801:Humans; D008055:Lipids / Q000502:physiology*; D008099:Liver / Q000473:pathology / Q000503:physiopathology; D051780:Sterol Regulatory Element Binding Protein 1 / Q000502:physiology; D015534:Trans-Activators / Q000633:toxicity*; D054334:Viral Regulatory and Accessory Proteins
D006511:Hepatitis B Antigens; D008055:Lipids; C497387:SREBF1 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D019870:1-Phosphatidylinositol 4-Kinase