Autophagy releases lipid that promotes fibrogenesis by activated hepatic stellate cells in mice and in human tissues

Virginia Hernndezgea, Zahra Ghiassinejad, Raphael Rozenfeld, Ronald Gordon, Maria Isabel Fiel, Zhenyu Yue, Mark J. Czaja, Scott L. Friedman

Research output: Contribution to journalArticle

274 Citations (Scopus)

Abstract

Background & Aims: The pathogenesis of liver fibrosis involves activation of hepatic stellate cells, which is associated with depletion of intracellular lipid droplets. When hepatocytes undergo autophagy, intracellular lipids are degraded in lysosomes. We investigated whether autophagy also promotes loss of lipids in hepatic stellate cells to provide energy for their activation and extended these findings to other fibrogenic cells. Methods: We analyzed hepatic stellate cells from C57BL/6 wild-type, Atg7 F/F, and Atg7 F/F-GFAP-Cre mice, as well as the mouse stellate cell line JS1. Fibrosis was induced in mice using CCl 4 or thioacetamide (TAA); liver tissues and stellate cells were analyzed. Autophagy was blocked in fibrogenic cells from liver and other tissues using small interfering RNAs against Atg5 or Atg7 and chemical antagonists. Human pulmonary fibroblasts were isolated from samples of lung tissue from patients with idiopathic pulmonary fibrosis or from healthy donors. Results: In mice, induction of liver injury with CCl 4 or TAA increased levels of autophagy. We also observed features of autophagy in activated stellate cells within injured human liver tissue. Loss of autophagic function in cultured mouse stellate cells and in mice following injury reduced fibrogenesis and matrix accumulation; this effect was partially overcome by providing oleic acid as an energy substrate. Autophagy also regulated expression of fibrogenic genes in embryonic, lung, and renal fibroblasts. Conclusions: Autophagy of activated stellate cells is required for hepatic fibrogenesis in mice. Selective reduction of autophagic activity in fibrogenic cells in liver and other tissues might be used to treat patients with fibrotic diseases.

Original languageEnglish (US)
Pages (from-to)938-946
Number of pages9
JournalGastroenterology
Volume142
Issue number4
DOIs
StatePublished - Apr 2012

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Hepatic Stellate Cells
Autophagy
Lipids
Liver
Thioacetamide
Lung
Fibroblasts
Idiopathic Pulmonary Fibrosis
Wounds and Injuries
Oleic Acid
Lysosomes
Liver Cirrhosis
Small Interfering RNA
Hepatocytes
Fibrosis
Tissue Donors
Kidney
Gene Expression
Cell Line

Keywords

  • Energy Depletion
  • Inflammation
  • Mouse Model
  • Myofibroblasts

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Hernndezgea, V., Ghiassinejad, Z., Rozenfeld, R., Gordon, R., Fiel, M. I., Yue, Z., ... Friedman, S. L. (2012). Autophagy releases lipid that promotes fibrogenesis by activated hepatic stellate cells in mice and in human tissues. Gastroenterology, 142(4), 938-946. https://doi.org/10.1053/j.gastro.2011.12.044

Autophagy releases lipid that promotes fibrogenesis by activated hepatic stellate cells in mice and in human tissues. / Hernndezgea, Virginia; Ghiassinejad, Zahra; Rozenfeld, Raphael; Gordon, Ronald; Fiel, Maria Isabel; Yue, Zhenyu; Czaja, Mark J.; Friedman, Scott L.

In: Gastroenterology, Vol. 142, No. 4, 04.2012, p. 938-946.

Research output: Contribution to journalArticle

Hernndezgea, V, Ghiassinejad, Z, Rozenfeld, R, Gordon, R, Fiel, MI, Yue, Z, Czaja, MJ & Friedman, SL 2012, 'Autophagy releases lipid that promotes fibrogenesis by activated hepatic stellate cells in mice and in human tissues', Gastroenterology, vol. 142, no. 4, pp. 938-946. https://doi.org/10.1053/j.gastro.2011.12.044
Hernndezgea, Virginia ; Ghiassinejad, Zahra ; Rozenfeld, Raphael ; Gordon, Ronald ; Fiel, Maria Isabel ; Yue, Zhenyu ; Czaja, Mark J. ; Friedman, Scott L. / Autophagy releases lipid that promotes fibrogenesis by activated hepatic stellate cells in mice and in human tissues. In: Gastroenterology. 2012 ; Vol. 142, No. 4. pp. 938-946.
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