[Nuclear receptor Nur77 inhibits oxidized low density lipoprotein induced lipid loading in macrophages].
OBJECTIVE
To observe the effect of Nur77 on lipid loading in macrophages exposed to 40 microg/ml oxidized low density lipoprotein (ox-LDL).


METHODS
Stable RAW264.7 strain expressing green fluorescent protein (GFP) or GFP-Nur77 was established by G418 screening after transfection with corresponding plasmids and identified by Western blot. After 24 h stimulation with ox-LDL, intracellular lipid loading of each strain was observed by Oil Red O dyeing, and the intracellular cholesterol level was measured by liquid chromatographic-mass spectrometry (LC-MS). The transcriptional changes of CD36 and ABCA1 were monitored by Real Time Quantitative-PCR, while the expressions of these two proteins were assayed by flow cytometry and Western blot, respectively.


RESULTS
After 24 h stimulation with ox-LDL, intracellular total cholesterol and esterified cholesterol concentration in GFP-Nur77-RAW264.7 were significantly dropped by 26.15% and 30.93% respectively (P < 0.05 vs. GFP-RAW264.7). The transcription and expression of ABCA1 in GFP-Nur77-RAW264.7 were significantly increased while the transcription and expression of CD36 were significantly reduced (all P < 0.05 vs. GFP-RAW264.7).


CONCLUSIONS
Orphan nuclear receptor Nur77 reduced ox-LDL induced intracellular lipid loading in macrophages by inhibiting lipid influx and enhancing lipid efflux.
Hu
Liu-hua
LH
Department of Cardiology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200001, China.
He
Ben
B
Shen
Ling-hong
LH
Zhou
Lei
L
Pu
Jun
J
Jiang
Li-sheng
LS
Shao
Qin
Q
Wang
Li
L
Zeng
Jin-Zhang
JZ
D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism*; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics*; D050356:Lipid Metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D011987:Receptors, Steroid / Q000235:genetics*; D014162:Transfection
D018955:CD36 Antigens; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D008077:Lipoproteins, LDL; C539818:Nr4a1 protein, mouse; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D011987:Receptors, Steroid; C099252:oxidized low density lipoprotein; D002784:Cholesterol