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Gastroenterology. 2012 Nov;143(5):1319-1329.e11. doi: 10.1053/j.gastro.2012.07.115. Epub 2012 Aug 8.

Hedgehog controls hepatic stellate cell fate by regulating metabolism.

Author information

1
Division of Gastroenterology, Department of Medicine, Duke University Medical Center, Durham, North Carolina.
2
Division of Gastroenterology, Department of Medicine, Duke University Medical Center, Durham, North Carolina; Section of Gastroenterology, Department of Medicine, Durham Veterans Affairs Medical Center, Durham, North Carolina.
3
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina.
4
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina; Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; Department of Pathology, Duke University Medical Center, Durham, North Carolina.
5
Division of Gastroenterology, Department of Medicine, Duke University Medical Center, Durham, North Carolina. Electronic address: diehl004@mc.duke.edu.

Abstract

BACKGROUND & AIMS:

The pathogenesis of cirrhosis, a disabling outcome of defective liver repair, involves deregulated accumulation of myofibroblasts derived from quiescent hepatic stellate cells (HSCs), but the mechanisms that control transdifferentiation of HSCs are poorly understood. We investigated whether the Hedgehog (Hh) pathway controls the fate of HSCs by regulating metabolism.

METHODS:

Microarray, quantitative polymerase chain reaction, and immunoblot analyses were used to identify metabolic genes that were differentially expressed in quiescent vs myofibroblast HSCs. Glycolysis and lactate production were disrupted in HSCs to determine if metabolism influenced transdifferentiation. Hh signaling and hypoxia-inducible factor 1α (HIF1α) activity were altered to identify factors that alter glycolytic activity. Changes in expression of genes that regulate glycolysis were quantified and localized in biopsy samples from patients with cirrhosis and liver samples from mice following administration of CCl(4) or bile duct ligation. Mice were given systemic inhibitors of Hh to determine if they affect glycolytic activity of the hepatic stroma; Hh signaling was also conditionally disrupted in myofibroblasts to determine the effects of glycolytic activity.

RESULTS:

Transdifferentiation of cultured, quiescent HSCs into myofibroblasts induced glycolysis and caused lactate accumulation. Increased expression of genes that regulate glycolysis required Hh signaling and involved induction of HIF1α. Inhibitors of Hh signaling, HIF1α, glycolysis, or lactate accumulation converted myofibroblasts to quiescent HSCs. In diseased livers of animals and patients, numbers of glycolytic stromal cells were associated with the severity of fibrosis. Conditional disruption of Hh signaling in myofibroblasts reduced numbers of glycolytic myofibroblasts and liver fibrosis in mice; similar effects were observed following administration of pharmacologic inhibitors of Hh.

CONCLUSIONS:

Hedgehog signaling controls the fate of HSCs by regulating metabolism. These findings might be applied to diagnosis and treatment of patients with cirrhosis.

PMID:
22885334
PMCID:
PMC3480563
DOI:
10.1053/j.gastro.2012.07.115
[Indexed for MEDLINE]
Free PMC Article

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