title: IGFBPrP1 induces liver fibrosis by inducing hepatic stellate cell activation and hepatocyte apoptosis via Smad2/3 signaling.
abstract: OBJECTIVE
  To investigate the role and mechanism of insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) in the development of liver fibrosis.
  
  
  METHODS
  An in vitro model using hepatic stellate cell (HSC)-T6 cells and an in vivo model of rat liver overexpressing IGFBPrP1 were established using an IGFBPrP1-expressing recombinant adenovirus. The expression of IGFBPrP1 was examined by immunofluorescence, and the expression of collagen I and fibronectin was measured by real-time reverse transcription-polymerase chain reaction and Western blot analysis. The expression of Smad2/3 and p-Smad2/3 was examined by Western blot and immunohistochemistry. A shSmad3-expressing recombinant adenovirus (AdshSmad3) was designed and used to knockdown the Smad3 gene in HSC-T6 cells and rat liver fibrosis transfected with IGFBPrP1. The expression of collagen I, fibronectin, and α-smooth muscle actin (α-SMA) was determined by Western blot analysis and immunohistochemistry. Hepatocyte apoptosis was assessed using TUNEL assay.
  
  
  RESULTS
  IGFBPrP1 overexpression induced collagen deposition and up-regulated the expression of α-SMA and p-Smad2/3, and AdshSmad3 inhibited IGFBPrP1-stimulated p-Smad2/3 activation and the expression of α-SMA, collagen I and fibronectin in HSC-T6 cells. Similarly, increased hepatocyte apoptosis (38.56% ± 3.42% vs 0.24% ± 0.03%, P < 0.05), α-SMA positive stained cells (29.84% ± 1.36% vs 5.83% ± 1.47%, P < 0.05), and increased numbers of Smad3 (35.88% ± 2.15% vs 10.24% ± 1.31%, P < 0.05) and p-Smad2/3 positive cells (28.87% ± 2.73% vs 8.23% ± 0.98%, P < 0.05) were detected in the livers of IGFBPrP1-overexpressing rats compared with the control group. Moreover, AdshSmad3 reduced IGFBPrP1-stimulated Smad3 expression and attenuated α-SMA expression (29.84% ± 1.36% vs 8.23% ± 1.28%, P < 0.05), hepatocyte apoptosis (38.56% ± 3.42% vs 6.75% ± 0.52%, P < 0.05), and both collagen I and fibronectin deposition in the livers of AdIGFBPrP1-treated rats.
  
  
  CONCLUSIONS
  IGFBPrP1 induces liver fibrosis by mediating the activation of hepatic stellate cells and hepatocyte apoptosis in a Smad3-dependent mechanism.
authors.affiliation: Yun Zhang, Department of Gastroenterology and Hepatology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Yun Zhang, Department of Gastroenterology and Hepatology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Zhang
authors.affiliation: Yun Zhang, Department of Gastroenterology and Hepatology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Guo
authors.affiliation: Yun Zhang, Department of Gastroenterology and Hepatology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Zhang
authors.affiliation: Yun Zhang, Department of Gastroenterology and Hepatology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China.
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Liu
mesh_terms: D000199:Actins / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D016922:Cellular Senescence; D003094:Collagen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology*; D007150:Immunohistochemistry; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000473:pathology*; D008297:Male; D008856:Microscopy, Fluorescence; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000378:metabolism; D051899:Smad2 Protein / Q000378:metabolism*; D051900:Smad3 Protein / Q000378:metabolism*
chemical_list: D000199:Actins; D003094:Collagen; D005353:Fibronectins; D018969:Insulin-Like Growth Factor Binding Proteins; D011994:Recombinant Proteins; D051899:Smad2 Protein; D051900:Smad3 Protein; C497784:Smad2 protein, rat; C497787:Smad3 protein, rat; C102529:insulin-like growth factor binding protein-related protein 1; C498862:Acta2 protein, rat
keywords: Hepatic stellate cells; Hepatocyte apoptosis; Insulin-like growth factor binding protein-related protein 1; Liver fibrosis; Smad pathway