Effect of Daxx on cholesterol accumulation in hepatic cells.
OBJECTIVE
To study the effect of Daxx on cholesterol accumulation in hepatic cells.


METHODS
Sprague Dawley (SD) rats were fed a normal or high fat diet for 6 wk, and serum lipids and Daxx expression of hepatic tissues were measured by immunoblot assays. HepG(2) cells were transfected with the pEGFP-C1/Daxx or pEGFP-C1 plasmid. Cells stably transfected with Daxx were identified by RT-PCR analysis. Total cholesterol levels were determined by high performance liquid chromatography. Activated-SREBP and caveolin-1 were assayed by western blotting.


RESULTS
Hepatic Daxx protein was higher in normal rats than in high fat diet-fed rats. Noticeable negative correlations were seen between Daxx and LDL-C (gamma = -7.56, P = 0.018), and between Daxx and TC (gamma = -9.07, P = 0.01), respectively. The total cholesterol of HepG(2)/GFP-Daxx cells was lower than that of control cells or HepG(2)/GFP cells (9.28 +/- 0.19 vs 14.36 +/- 4.45 or 13.94 +/- 2.62, both P < 0.05). Furthermore, in HepG(2)/GFP cells, the expression of activated SREBP was lower than that of control cells, whereas caveolin-1 expression was higher.


CONCLUSIONS
Overexpression of Daxx in HepG(2) cells decreased intracellular cholesterol accumulation, which might be associated with inhibition of SREBP activity and an increase in caveolin-1 expression.
Tuo
Qin-Hui
QH
School of Life Science and Technology, University of South China, Western Changsheng Road #28, Hengyang, Hunan Province, China.
Liang
Lei
L
Zhu
Bing-Yang
BY
Cao
Xuan
X
Liao
Duan-Fang
DF
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism*; D056970:Co-Repressor Proteins; D004041:Dietary Fats; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008297:Male; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D051779:Sterol Regulatory Element Binding Proteins / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D051242:Caveolin 1; D056970:Co-Repressor Proteins; C106985:DAXX protein, human; C528558:Daxx protein, rat; D004041:Dietary Fats; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D051779:Sterol Regulatory Element Binding Proteins; D002784:Cholesterol