Cholesteryl ester handling by RAW264 macrophages: response to native and acetylated low density lipoprotein

Kelly A. Berg, Howard R. Petty

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The effects of LDL and Ac-LDL on the growth properties, morphology, and cholesteryl ester (CE) metabolism of the RAW264 macrophage cell line have been characterized. Cells were grown in media supplemented by a defined media (DM) mixture or fetal bovine serum (FBS). The addition of LDL or Ac-LDL to the culture media did not significantly alter cell growth properties. Cytoplasmic deposition of CE was observed by fluorescence microscopy in macrophages treated with LDL or Ac-LDL but not in untreated controls. Dose-response studies have shown that cholesteryl ester (CE) can accumulate in RAW264 treated with LDL. Cellular cholesterol content saturated at 4 hours with 50 μg/ml LDL; this effect may be associated with receptor saturation. Dose-response studies conducted with Ac-LDL in DM have shown dramatic increases in total cell cholesterol content. However, deposition of CE was not observed below Ac-LDL concentrations of 100 μg/ml. This indicates that a critical concentration of Ac-LDL must be reached to trigger deposition in DM. In contrast, no critical concentration of Ac-LDL was observed in macrophages grown in medium supplemented with 10% FBS. Cholesterol esterification in response to LDL and Ac-LDL was examined by 14C-oleic acid incorporation into CE. These results confirmed the mass cellular cholesterol and CE measurements. Kinetic studies conducted with RAW264 cells treated with 50 or 100 μg/ml Ac-LDL resulted in a cholesterol efflux from the cells at 6-12 hours of incubation. Therefore, these studies show that (1) the nature of CE deposition is highly dependent upon the incubation media and (2) CE deposition is very sensitive to Ac-LDL concentration under certain conditions.

Original languageEnglish (US)
Pages (from-to)29-40
Number of pages12
JournalMolecular and Cellular Biochemistry
Volume84
Issue number1
DOIs
StatePublished - Nov 1 1988
Externally publishedYes

Keywords

  • LDL
  • acetyl-LDL
  • cholesteryl ester depostion
  • macrophage

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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