title: miR-200a controls hepatic stellate cell activation and fibrosis via SIRT1/Notch1 signal pathway.
abstract: OBJECTIVE
  miR-200a has been established as a key regulator of HSC activation processes in liver fibrosis. Epigenetic silencing of miR-200a contributing to SIRT1 over-expression has been discussed in breast cancer; however, whether miR-200a controls SIRT1 gene expression in hepatic fibrosis is still unknown.
  
  
  METHODS
  We analyzed miR-200a regulation of SIRT1 expression in CCl4-induced liver fibrosis and TGF-β1-mediated activation of HSC. miR-200a, SIRT1, α-SMA, Col1A1, Notch1 and NICD expression were estimated by Western blotting, qRT-PCR and Immunohistochemistry. HSCs were transfected with miR-200a mimic, miR-200a inhibitor and SIRT1-RNAi. Luciferase reporter assays further confirmed the interaction between miR-200a and the SIRT1 mRNA 3'-UTR. Cell proliferation ability was assessed by MTT and cell cycle.
  
  
  RESULTS
  We found that treatment activated HSC with miR-200a mimics, restored miR-200a expression and reduced SIRT1 levels. Conversely, treatment activated HSC with miR-200a inhibitors, decreased miR-200a expression and up-regulated SIRT1 levels. Restoration of miR-200a or the knockdown of SIRT1 prevented HSC activation and proliferation. We have established the SIRT1 transcript as subject to regulation by miR-200a, through miR-200a targeting of SIRT1 3'-UTR. Finally, HSC transfected with SIRT1-siRNA increased the levels of Notch1 protein and mRNA expression.
  
  
  CONCLUSIONS
  Our study demonstrated that miR-200a regulates SIRT1/Notch1 expression during HSC activation and fibrosis.
authors.affiliation: Department of Pharmacology, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Yang
authors.affiliation: Department of Cardiothoracic Surgery, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Tao
authors.affiliation: Department of Pharmacology, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Department of Scientific, The Second Hospital of Anhui Medical University, Hefei, 230601, China.
authors.forename: Zi-Yu
authors.initials: ZY
authors.lastname: Deng
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui, 230032, China. yncs01@hotmail.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008103:Liver Cirrhosis / Q000378:metabolism* / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1
chemical_list: C555600:MIRN200 microRNA, rat; D035683:MicroRNAs; C497763:Notch1 protein, rat; D051881:Receptor, Notch1; D053773:Transforming Growth Factor beta1; C488368:Sirt1 protein, rat; D056564:Sirtuin 1
keywords: Hepatic stellate cells; Liver fibrosis; MicroRNA-200a