Effects of oxidized low-density lipoprotein on cholesterol efflux in 3T3-L1 cells.
- Author:
Bi-Lian YU
1
;
Shui-Ping ZHAO
;
Xiang-Zhu XIE
;
Shao-Zhuang DONG
;
Jing DONG
Author Information
1. Department of Cardiology, Second Xiangya Hospital, Central South University, Changsha 410011, China.
- Publication Type:Journal Article
- MeSH:
3T3-L1 Cells;
ATP Binding Cassette Transporter 1;
metabolism;
Adipocytes;
drug effects;
metabolism;
Animals;
Cholesterol;
metabolism;
Lipid Metabolism;
Lipoproteins, LDL;
pharmacology;
Liver X Receptors;
Mice;
Orphan Nuclear Receptors;
metabolism;
Scavenger Receptors, Class B;
metabolism
- From:
Journal of Central South University(Medical Sciences)
2007;32(4):631-636
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To explore whether oxidized low-density lipoprotein (ox-LDL) can stimulate the cholesterol efflux in fully differentiated 3T3-L1 cells and the possible mechanism.
METHODS:Fully differentiated 3T3-L1 cells were incubated in the medium containing various concentrations of ox-LDL ( 0 to 50 microg/mL) for 8 or 24 hours. 22(R)-Hydroxycholesterol (10 micromol/L) was exposed to preconditioned adipocytes with 25 microg/mL ox-LDL for 24 hours. Reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate ATP binding cassette transporter A1 (ABCA1), scavenger receptor class B type I (SR-BI), and liver X receptor alpha (LXRalpha) mRNA expression. Cholesterol efflux mediated by apolipoprotein A-I (apoA-I) was determined using liquid scintillator.
RESULTS:Low levels (12.5-25 microg/mL) of ox-LDL could increase cholesterol efflux via the enhancement of ABCA1 pathway and SR-BI expression, whereas the higher concentration (50 microg/mL) could not. In adipocytes preincubated with 25 microg/mL ox-LDL for 24 hours, 22(R)-hydroxycholesterol could increase ABCA1 and LXRalpha mRNA and apoA-I-mediated cholesterol efflux, but had no effect on the SR-BI mRNA expression.
CONCLUSION:Low levels of ox-LDL may enhance the LXRalpha-ABCA1-apoA-I pathway in adipocytes, up-regulate SR-BI mRNA expression, and then increase the cholesterol efflux. This new effect of ox-LDL will not only make contribution to cholesterol homeostasis in adipocytes, but also be potentially atheroprotective.
