title: [Adiponectin inhibits the activation of hepatic stellate cells induced by TGFb1 via up-regulating the expression of eNOS].
abstract: OBJECTIVE
  To investigate the molecular mechanism of adiponectin inhibiting activation of hepatic stellate cells in non-alcoholic fatty liver fibrosis.
  
  
  METHODS
  The rat models of non-alcoholic fatty liver fibrosis were successfully established by fat-rich diet administration. The expression of adiponectin mRNA and protein were respectively detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. LX-2 cells were cultured in an adipogenic differentiation mixture to induce quiescent adipocytic phenotypes, and then they were treated with TGFβ1, adiponectin and TGFβ1 + adiponectin, respectively. RT-PCR and Western blot were used to determine the expressions of mRNAs and proteins of a-smooth muscle actin (a-SMA), Collagen, adenosine monophosphate-activated protein kinase (AMPK), inducible nitric oxide synthase (iNOS), and endothelial NOS (eNOS). The results were analyzed using one-way ANOVA, Student-Newman-Keuls test, and linear correlation analysis. A P value of less than 0.05 was considered as statistically significant.
  
  
  RESULTS
  In vivo, with the progress of non-alcoholic fatty liver fibrosis, the model rats gradually showed hepatic steatosis, inflammation, necrosis and fibrosis. Compared with the control group, the level of serum adiponectin (2.49 ± 0.86 vs 5.81 ± 0.87, P < 0.05) and hepatic expressions of adiponectin mRNA and protein (0.26 ± 0.04 vs 0.72 ± 0.08; 0.64 ± 0.07 vs 0.21 ± 0.07, all P < 0.05) were all decreased in the 24th week group, and were negatively correlated with the level of Collagen which increased gradually. In vitro, TGFβ1 could activate quiescent LX-2 cells by decreasing mRNA and protein expression of eNOS (0.30 ± 0.10 vs 0.44 ± 0.08; 0.30 ± 0.09 vs 0.46 ± 0.07, all P < 0.05) and increasing the expression of iNOS (0.53 ± 0.07 vs 0.37 ± 0.04; 0.55 ± 0.07 vs 0.39 ± 0.05, all P < 0.05). Recombinant adiponectin not only maintained the quiescent phenotype of LX-2 cells but also inhibited LX-2 cells activation due to TGFβ1 by increasing the expression of eNOS (0.43 ± 0.08 vs 0.30 ± 0.10; 0.42 ± 0.07 vs 0.30 ± 0.09, all P < 0.05) and phosphorylation of AMPK (0.43 ± 0.07 vs 0.24 ± 0.04, P < 0.05) and decreasing the expression of iNOS (0.44 ± 0.05 vs 0.53 ± 0.07; 0.46 ± 0.07 vs 0.55 ± 0.07, all P < 0.05).
  
  
  CONCLUSIONS
  Data suggested that adiponectin could play a protective role on the pathogenesis of non-alcoholic fatty liver fibrosis by inhibiting the activation of hepatic stellate cells via up-regulating the expression of eNOS, which might associate with increased phosphorylation of AMPK.
authors.affiliation: Department of Infectious Diseases, The Third Affiliated Hospital of Hebei Medical University, Shijiazhuang 050051, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Cai-yan
authors.initials: CY
authors.lastname: Zhao
authors.forename: Ya-dong
authors.initials: YD
authors.lastname: Wang
authors.forename: Xian
authors.initials: X
authors.lastname: He
authors.forename: Chuan
authors.initials: C
authors.lastname: Shen
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Jun-ying
authors.initials: JY
authors.lastname: Zhou
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhen
mesh_terms: D052242:Adiponectin / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000378:metabolism; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000378:metabolism / Q000473:pathology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D065626:Non-alcoholic Fatty Liver Disease; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D052242:Adiponectin; D053773:Transforming Growth Factor beta1; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat