Intracellular cholesterol mobilization involved in the ABCA1/apolipoprotein-mediated assembly of high density lipoprotein in fibroblasts
Differential regulation has been suggested for cellular cholesterol and phospholipid release mediated by apolipoprotein A-I (apoA-I)/ABCA1. We investigated various factors involved in cholesterol mobilization related to this pathway. ApoA-I induced a rapid decrease of the cellular cholesterol compar...
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Published in | Journal of lipid research Vol. 45; no. 10; pp. 1943 - 1951 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.10.2004
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Differential regulation has been suggested for cellular cholesterol and phospholipid release mediated by apolipoprotein A-I (apoA-I)/ABCA1. We investigated various factors involved in cholesterol mobilization related to this pathway. ApoA-I induced a rapid decrease of the cellular cholesterol compartment that is in equilibrium with the ACAT-accessible pool in cells that generate cholesterol-rich HDL. Pharmacological and genetic inactivation of ACAT enhanced the apoA-I-mediated cholesterol release through upregulation of ABCA1 and through cholesterol enrichment in the HDL generated. Pharmacological activation of protein kinase C (PKC) also decreased the ACAT-accessible cholesterol pool, not only in the cells that produce cholesterol-rich HDL by apoA-I (i.e., human fibroblast WI-38 cells) but also in the cells that generate cholesterol-poor HDL (mouse fibroblast L929 cells). In L929 cells, the PKC activation caused an increase in apoA-I-mediated cholesterol release without detectable change in phospholipid release and in ABCA1 expression.
These results indicate that apoA-I mobilizes intracellular cholesterol for the ABCA1-mediated release from the compartment that is under the control of ACAT. The cholesterol mobilization process is presumably related to PKC activation by apoA-I. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-2275 1539-7262 |
DOI: | 10.1194/jlr.M400264-JLR200 |