title: [SREBP-1c knockdown attenuated fatty degeneration in hepatic L02 cells and inhibited CCL2 and FGF21 protein expression].
abstract: OBJECTIVE
  To study the effect of SREBP-1c silencing on lipid metabolism and expression of inflammatory chemokines in a NAFLD model with endoplasmic reticulum stress.
  
  
  METHODS
  NAFLD model was established in L02 cells treated with oleic acid. SREBP-1c expression was inhibited using RNA interference with a p Silencer-1.0-U6-4476 vector. After transfection with p Silencer-1.0-U6-4476 or control vector for 0 h, 24 h, 48 h and 72 h, the extent of fatty degeneration was shown by Oil Red O staining. The mRNA and protein expression of inflammatory chemokine CCL2 and basic fibroblast growth factor-21 (FGF21) were determined by real time PCR and Western blot respectively.
  
  
  RESULTS
  SREBP-1c silenced L02 cells showed fat droplets with smaller diameter and attenuated fatty deposition, as compared with control cells. The relative CCL2 mRNA levels in SREBP-1c silencing vector transfected L02 cells were 1.03+/-0.11 for 0 h, 1.11+/-0.21 for 24 h, 0.88+/-0.16 for 48 h, and 1.05+/-0.15 for 72 h, which showed no significant difference as compared with control cells (P>0.05, respectively). In addition, no difference was found between the different time points within the same group (P>0.05). However, CCL2 protein levels in SREBP-1c silenced cells were 1.19+/-0.15, 1.07+/-0.18, 0.48+/-0.14, and 0.05+/-0.24 after transfection for 0 h, 24 h, 48 h, and 72 h respectively, which were significantly downregulated as compared to the control group (P<0.01). And CCL2 protein levels between different time points in SREBP-1c silenced cells were also distinct (P<0.01). The relative FGF21 mRNA levels in SREBP-1c silenced L-02 cells were 1.01+/-0.08, 0.91+/-0.22, 0.98+/-0.20, and 1.02+/-0.12 for 0 h, 24 h, 48 h, and 72 h respectively, which were not statistically different as compared with the corresponding control cells. Statistic difference of FGF21 mRNA levels in SREBP-1c knockdown cells of different time points was not found (P>0.05). In striking contrast, robust down regulation of FGF21 protein in SREBP-1c silenced cells was observed, with 0.81+/-0.05, 0.66+/-0.12, 0.58+/-0.08 and 0.19+/-0.13 after transfection for 0 h, 24 h, 48 h and 72 h respectively, as compared to control group (P<0.01). And differences in FGF21 protein level between different time points in SREBP-1c silenced cells were also demonstrated (P<0.01).
  
  
  CONCLUSIONS
  SREBP-1c knockdown attenuated fatty deposition in oleic acid treated L02 cells. In addition, silencing of SREBP-1c expression reduced expressions of CCL2 and FGF21 proteins posttranscriptionally, which may play a role in endoplasmic reticulum stress induced inflammatory response in NAFLD.
authors.affiliation: Department of Gastroenterology, Daping Hospital and Institute of Field Surgery Research, Third Military Medical University, Chongqing 400042, China.
authors.forename: Wan-dong
authors.initials: WD
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Li-lin
authors.initials: LL
authors.lastname: Fan
authors.forename: Ji
authors.initials: J
authors.lastname: Xiong
authors.forename: Wen-jing
authors.initials: WJ
authors.lastname: Sun
authors.forename: Lu
authors.initials: L
authors.lastname: Hu
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Dong-feng
authors.initials: DF
authors.lastname: Chen
mesh_terms: D002460:Cell Line; D018932:Chemokine CCL2 / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D050356:Lipid Metabolism; D034622:RNA Interference; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics*
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D051780:Sterol Regulatory Element Binding Protein 1; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors