Metabolism of cholesteryl ester lipid droplets in a J774 macrophage foam cell model.
Biochim Biophys Acta
; 1045(3): 291-8, 1990 Aug 06.
Article
em En
| MEDLINE
| ID: mdl-2386801
ABSTRACT
J774 macrophages rapidly incorporated [3H]cholesteryl oleate droplets by a non-saturable phagocytic process. In less than 2 h, foam cell morphology was acquired. The extent of loading obtained after 2 h was a linear function of the mass of cholesteryl oleate provided to the cells. The cholesteryl oleate incorporated was hydrolyzed in the cells at a linear rate over 24 h and the fractional hydrolysis was constant over a wide range of cellular esterified cholesterol contents. The rate of hydrolysis was influenced by the physical state of the cholesteryl ester; cholesteryl oleate in isotropic droplets was hydrolyzed 2-3-fold more rapidly than cholesteryl oleate in anisotropic droplets. The hydrolysis of both types of droplets was inhibited by lysosomotropic agents, indicating that hydrolysis occurred in the lysosomes. Only a small fraction (less than 10% after 24 h) of the free [3H]cholesterol generated in the lysosomes was esterified by ACAT resulting in a doubling of the cell free cholesterol content. Electron microscopy of cells treated with digitonin revealed the accumulation of free cholesterol in lipid-laden lysosomes. ACAT was active as endogenous free [14C]cholesterol was esterified in a linear manner over 24 h and was responsive to the presence of lysosomally-derived cholesterol, as the extent of esterification of the endogenous pool was directly proportional to the mass of [3H]cholesterol generated in the lysosomes.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ésteres do Colesterol
/
Células Espumosas
/
Macrófagos
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1990
Tipo de documento:
Article