Oxidatively modified low density lipoproteins (Ox-LDL) may be involved in determining the formation of foam cells by inducing cellular cholesteryl ester accumulation. We studied the effect of copper oxidized LDL (Ox-LDL) on cholesterol accumulation and esterification in murine macrophages. Ox-LDL (44 ug/ml of lipoprotein cholesterol) increased the total cholesterol content of the cells from 29 to 69 ug/mg cell protein. Free cholesterol accounted for 85% of this increase. Acetyl LDL (Ac-LDL) (38 ug/ml of lipoprotein cholesterol), raised total cellular cholesterol content to a similar extent (76 ug/mg cell protein), however only 25% of the accumulated cholesterol was unesterified. When ACAT activity was determined after incubation of J774 cell with Ox- or Ac-LDL, Ox-LDL were 12 times less effective than Ac-LDL in stimulating cholesteryl ester formation. This was not due to an inhibition of ACAT by Ox-LDL since these lipoproteins failed to inhibit pre activated enzyme in cholesteryl ester-loaded macrophages. The uptake of 125I-Ox-LDL was 175% that of 125I-Ac-LDL, while degradation was only 20%. All together these data suggest an altered intracellular processing of Ox-LDL, which may be responsible for free cholesterol accumulation.
Oxidized LDL increase free cholesterol and fail to stimulate cholesterol esterification in murine macrophages / Roma, P.; Catapano, A. L.; Bertulli, S. M.; Varesi, L.; Fumagalli, R.; Bernini, F.. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - 171:1(1990), pp. 123-131. [10.1016/0006-291X(90)91365-Y]
Oxidized LDL increase free cholesterol and fail to stimulate cholesterol esterification in murine macrophages
Bernini F.
1990-01-01
Abstract
Oxidatively modified low density lipoproteins (Ox-LDL) may be involved in determining the formation of foam cells by inducing cellular cholesteryl ester accumulation. We studied the effect of copper oxidized LDL (Ox-LDL) on cholesterol accumulation and esterification in murine macrophages. Ox-LDL (44 ug/ml of lipoprotein cholesterol) increased the total cholesterol content of the cells from 29 to 69 ug/mg cell protein. Free cholesterol accounted for 85% of this increase. Acetyl LDL (Ac-LDL) (38 ug/ml of lipoprotein cholesterol), raised total cellular cholesterol content to a similar extent (76 ug/mg cell protein), however only 25% of the accumulated cholesterol was unesterified. When ACAT activity was determined after incubation of J774 cell with Ox- or Ac-LDL, Ox-LDL were 12 times less effective than Ac-LDL in stimulating cholesteryl ester formation. This was not due to an inhibition of ACAT by Ox-LDL since these lipoproteins failed to inhibit pre activated enzyme in cholesteryl ester-loaded macrophages. The uptake of 125I-Ox-LDL was 175% that of 125I-Ac-LDL, while degradation was only 20%. All together these data suggest an altered intracellular processing of Ox-LDL, which may be responsible for free cholesterol accumulation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
