Downregulation of hepatic stellate cell activation by retinol and palmitate mediated by Adipose Differentiation-Related Protein (ADRP)

Ting Fang Lee, Ki M. Mak, Ori Rackovsky, Yun Lian Lin, Allison J. Kwong, Johnny C. Loke, Scott L. Friedman

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

Hepatic stellate cells (HSCs) store retinoids and triacylglycerols in cytoplasmic lipid droplets. Twoprominent features of HSCactivation in liver fibrosis are loss of lipid droplets along with increase of a-smooth muscle actin (a-SMA), but the link between these responses and HSC activation remains elusive. In non-adipose cells, adipose differentiation-related protein (ADRP) coats lipid droplets and regulates their formation and lipolysis; however its function in HSCs is unknown. Here, we observed, in human liver sections or primary HSC culture, ADRP localization to lipid droplets of HSCs, and reduced staining coincident with loss of lipid droplets in liver fibrosis and in culture-activated HSCs, consistent with HSC activation. In the LX-2 human immortalized HSCs, with scant lipid droplets and features of activated HSCs, we found that the upregulation of ADRP mRNA by palmitate is potentiated by retinol, accompanied by increased ADRP protein, generation of retinyl palmitate, and lipid droplet formation. ADRP induction also led to decreased expression of a-SMA mRNA and its protein, while ADRP knockdown with small interfering RNA (siRNA) normalized a-SMA expression. Furthermore, ADRP induction by retinol and palmitate resulted in decreased expression of collagen I and matrix metalloproteinase-2 mRNA, fibrogenic genes associated with activated HSCs, while increasing matrix metalloproteinase-1 mRNA; ADRP knockdown with siRNA reversed these changes. Tissue inhibitor of metalloproteinase-1 was not affected. Thus, ADRP upregulation mediated by retinol and palmitate promotes downregulation of HSC activation and is functionally linked to the expression of fibrogenic genes.

Original languageEnglish (US)
Pages (from-to)648-657
Number of pages10
JournalJournal of Cellular Physiology
Volume223
Issue number3
DOIs
StatePublished - Jun 2010
Externally publishedYes

Fingerprint

Hepatic Stellate Cells
Down-Regulation
Chemical activation
Lipids
Proteins
Liver
Smooth Muscle
Muscle
Actins
Messenger RNA
Liver Cirrhosis
Small Interfering RNA
retinol palmitate
Perilipin-2
Up-Regulation
Genes
Matrix Metalloproteinase 1
Tissue Inhibitor of Metalloproteinase-1
Palmitates
Lipolysis

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

Cite this

Downregulation of hepatic stellate cell activation by retinol and palmitate mediated by Adipose Differentiation-Related Protein (ADRP). / Lee, Ting Fang; Mak, Ki M.; Rackovsky, Ori; Lin, Yun Lian; Kwong, Allison J.; Loke, Johnny C.; Friedman, Scott L.

In: Journal of Cellular Physiology, Vol. 223, No. 3, 06.2010, p. 648-657.

Research output: Contribution to journalArticle

Lee, Ting Fang ; Mak, Ki M. ; Rackovsky, Ori ; Lin, Yun Lian ; Kwong, Allison J. ; Loke, Johnny C. ; Friedman, Scott L. / Downregulation of hepatic stellate cell activation by retinol and palmitate mediated by Adipose Differentiation-Related Protein (ADRP). In: Journal of Cellular Physiology. 2010 ; Vol. 223, No. 3. pp. 648-657.
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