Impairment of hepatic growth hormone and glucocorticoid receptor signaling causes steatosis and hepatocellular carcinoma in mice

Kristina M Mueller, Jan-Wilhelm Kornfeld, Katrin Friedbichler, Leander Blaas, Gerda Egger, Harald Esterbauer, Peter Hasselblatt, Michaela Schlederer, Susanne Haindl, Kay-Uwe Wagner, David Engblom, Guenter Haemmerle, Dagmar Kratky, Veronika Sexl, Lukas Kenner, Andrey V Kozlov, Luigi Terracciano, Rudolf Zechner, Guenther Schuetz, Emilio CasanovaJ Andrew Pospisilik, Markus H Heim, Richard Moriggl

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Abstract

UNLABELLED: Growth hormone (GH)-activated signal transducer and activator of transcription 5 (STAT5) and the glucocorticoid (GC)-responsive glucocorticoid receptor (GR) are important signal integrators in the liver during metabolic and physiologic stress. Their deregulation has been implicated in the development of metabolic liver diseases, such as steatosis and progression to fibrosis. Using liver-specific STAT5 and GR knockout mice, we addressed their role in metabolism and liver cancer onset. STAT5 single and STAT5/GR double mutants developed steatosis, but only double-mutant mice progressed to liver cancer. Mechanistically, STAT5 deficiency led to the up-regulation of prolipogenic sterol regulatory element binding protein 1 (SREBP-1) and peroxisome proliferator activated receptor gamma (PPAR-γ) signaling. Combined loss of STAT5/GR resulted in GH resistance and hypercortisolism. The combination of both induced expression of adipose tissue lipases, adipose tissue lipid mobilization, and lipid flux to the liver, thereby aggravating STAT5-dependent steatosis. The metabolic dysfunctions in STAT5/GR compound knockout animals led to the development of hepatic dysplasia at 9 months of age. At 12 months, 35% of STAT5/GR-deficient livers harbored dysplastic nodules and ∼ 60% hepatocellular carcinomas (HCCs). HCC development was associated with GH and insulin resistance, enhanced tumor necrosis factor alpha (TNF-α) expression, high reactive oxygen species levels, and augmented liver and DNA damage parameters. Moreover, activation of the c-Jun N-terminal kinase 1 (JNK1) and STAT3 was prominent.

CONCLUSION: Hepatic STAT5/GR signaling is crucial for the maintenance of systemic lipid homeostasis. Impairment of both signaling cascades causes severe metabolic liver disease and promotes spontaneous hepatic tumorigenesis.

OriginalsprogEngelsk
TidsskriftHepatology (Baltimore, Md.)
Vol/bind54
Udgave nummer4
Sider (fra-til)1398-409
ISSN0270-9139
DOI
StatusUdgivet - okt. 2011
Udgivet eksterntJa

Bibliografisk note

Copyright © 2011 American Association for the Study of Liver Diseases.

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