SREBP-1c gene silencing can decrease lipid deposits in bovine hepatocytes cultured in vitro.
BACKGROUND
Fatty liver is a major metabolic disorder that occurs during early lactation in high-producing dairy cows. Sterol regulatory element-binding protein-1c (SREBP-1c) is an important transcription factor that regulates lipid synthesis by regulating the expression of lipid metabolism genes.


METHODS
In this study, we reduced the expression of SREBP-1c by adenovirus-mediated SREBP-1c with a low expression vector (AD-GFP-SREBP-1c) to study the effects of SREBP-1c on lipid deposits in bovine hepatocytes. The expression levels and enzyme activities of SERBP-1c and its target genes were determined by real-time PCR, western blot, and ELISA.


RESULTS
These results showed that Ad-GFP-SREBP-1c could inhibit SREBP-1c expression. The expression of the lipid synthesis enzyme acetyl-CoA carboxylase (ACC) was down-regulated. The expression levels of the lipid oxidation enzymes long-chain fatty acyl-COA synthetase (ACSL-1), carnitine palmitoyltransferase І (CPT-І), carnitine palmitoyltransferase II (CPT- II), and β-hydroxyacyl-CoA-DH (HADH) were significantly elevated. Furthermore, the expression levels of factors involved in the assembly and transport of very low-density lipoproteins (VLDLs), such as apolipoprotein B100 (ApoB), apolipoprotein E (ApoE), and microsomal triglyceride transfer protein (MTTP) were decreased comparison with the negative control and the blank control groups, but the low-density lipoprotein receptor (LDLR) was elevated. The concentrations of TG (triglyceride) and VLDL were also reduced.


CONCLUSIONS
These data suggest that low SREBP-1c expression can decrease lipid synthesis, increase lipid oxidation, and decrease the TG and VLDL content in bovine hepatocytes.
Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China.
Qinghua
Q
Deng
Xinwei
X
Li
Shixin
S
Fu
Liheng
L
Yin
Yuming
Y
Zhang
Tingting
T
Wang
Jianguo
J
Wang
Lei
L
Liu
Xue
X
Yuan
Guoquan
G
Sun
Zhe
Z
Wang
Guowen
G
Liu
Xiaobing
X
Li
D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D020868:Gene Silencing; D022781:Hepatocytes / Q000166:cytology* / Q000378:metabolism*; D050356:Lipid Metabolism; D051780:Sterol Regulatory Element Binding Protein 1 / Q000172:deficiency* / Q000235:genetics* / Q000378:metabolism
D051780:Sterol Regulatory Element Binding Protein 1