Sterol regulation of scavenger receptor class B type I in macrophages

Liqing Yu, Guoqing Cao, Joyce Repa, Herbert Stangl

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Scavenger receptor class B type I (SR-BI) is expressed in macrophages, but its role in sterol trafficking in these cells remains controversial. We examined the effect of sterol loading on SR-BI expression in human monocytes/macrophages, mouse peritoneal macrophages, and a cultured mouse macrophage cell line (J774 cells). Sterol loading using either acetylated LDL or 25-hydroxycholesterol resulted in a time- and concentration-dependent decrease in SR-BI protein and mRNA levels. Treatment of lipid-loaded J774 cells with cyclodextrin or HDL to promote cellular sterol efflux was associated with an increase in SR-BI expression. Studies were performed to determine if the sterol-associated downregulation of SR-BI in macrophages was mediated by either sterol regulatory element binding proteins (SREBPs) or the liver X receptor (LXR). Expression of constitutively active SREBPs failed to alter the expression of a luciferase reporter placed downstream of a 2,556 bp 5′ flanking sequence from the mouse SR-BI gene. Reduction in SR-BI expression was also seen in sterol-loaded peritoneal macrophages from mice expressing no LXRα and LXRβ. We conclude that SR-BI levels in macrophages are responsive to changes in intracellular sterol content and that these sterol-associated changes are not mediated by LXR and are unlikely to be mediated by an SREBP pathway.

Original languageEnglish (US)
Pages (from-to)889-899
Number of pages11
JournalJournal of Lipid Research
Volume45
Issue number5
DOIs
StatePublished - May 2004

Fingerprint

CD36 Antigens
Macrophages
Sterols
Sterol Regulatory Element Binding Proteins
Liver
Peritoneal Macrophages
MHC Class I Genes
5' Flanking Region
Cyclodextrins
Luciferases
Monocytes
Down-Regulation
Genes
Cells
Lipids
Cell Line
Messenger RNA
Liver X Receptors

Keywords

  • Cholesterol
  • Mouse scavenger receptor class B type I promoter
  • Regulation

ASJC Scopus subject areas

  • Endocrinology

Cite this

Sterol regulation of scavenger receptor class B type I in macrophages. / Yu, Liqing; Cao, Guoqing; Repa, Joyce; Stangl, Herbert.

In: Journal of Lipid Research, Vol. 45, No. 5, 05.2004, p. 889-899.

Research output: Contribution to journalArticle

Yu, Liqing ; Cao, Guoqing ; Repa, Joyce ; Stangl, Herbert. / Sterol regulation of scavenger receptor class B type I in macrophages. In: Journal of Lipid Research. 2004 ; Vol. 45, No. 5. pp. 889-899.
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