title: A novel murine model to deplete hepatic stellate cells uncovers their role in amplifying liver damage in mice.
abstract: We have developed a novel model for depleting mouse hepatic stellate cells (HSCs) that has allowed us to clarify their contributions to hepatic injury and fibrosis. Transgenic (Tg) mice expressing the herpes simplex virus thymidine kinase gene (HSV-Tk) driven by the mouse GFAP promoter were used to render proliferating HSCs susceptible to killing in response to ganciclovir (GCV). Effects of GCV were explored in primary HSCs and in vivo. Panlobular damage was provoked to maximize HSC depletion by combining CCl(4) (centrilobular injury) with allyl alcohol (AA) (periportal injury), as well as in a bile duct ligation (BDL) model. Cell depletion in situ was quantified using dual immunofluorescence (IF) for desmin and GFAP. In primary HSCs isolated from both untreated wild-type (WT) and Tg mice, GCV induced cell death in ≈ 50% of HSCs from Tg, but not WT, mice. In TG mice treated with CCl(4) +AA+GCV, there was a significant decrease in GFAP and desmin-positive cells, compared to WT mice (≈ 65% reduction; P < 0.01), which was accompanied by a decrease in the expression of HSC-activation markers (alpha smooth muscle actin, beta platelet-derived growth factor receptor, and collagen I). Similar results were observed after BDL. Associated with HSC depletion in both fibrosis models, there was marked attenuation of fibrosis and liver injury, as indicated by Sirius Red/Fast Green, hematoxylin and eosin quantification, and serum alanine/aspartate aminotransferase. Hepatic expression of interleukin-10 and interferon-gamma was increased after HSC depletion. No toxicity of GCV in either WT or Tg mice accounted for the differences in injury.
  
  
  CONCLUSIONS
  Activated HSCs significantly amplify the response to liver injury, further expanding this cell type's repertoire in orchestrating hepatic injury and repair.
authors.affiliation: Division of Liver Diseases, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Puche
authors.forename: Youngmin A
authors.initials: YA
authors.lastname: Lee
authors.forename: Jingjing
authors.initials: J
authors.lastname: Jiao
authors.forename: Costica
authors.initials: C
authors.lastname: Aloman
authors.forename: Maria I
authors.initials: MI
authors.lastname: Fiel
authors.forename: Ursula
authors.initials: U
authors.lastname: Muñoz
authors.forename: Thomas
authors.initials: T
authors.lastname: Kraus
authors.forename: Tingfang
authors.initials: T
authors.lastname: Lee
authors.forename: Hal F
authors.initials: HF
authors.lastname: Yee
authors.forename: Scott L
authors.initials: SL
authors.lastname: Friedman
mesh_terms: D000818:Animals; D017209:Apoptosis; D002251:Carbon Tetrachloride; D002460:Cell Line; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology* / Q000473:pathology; D016207:Cytokines / Q000378:metabolism; D005355:Fibrosis; D015774:Ganciclovir; D005904:Glial Fibrillary Acidic Protein; D055166:Hepatic Stellate Cells / Q000502:physiology*; D008099:Liver / Q000276:immunology / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D020005:Propanols; D013937:Thymidine Kinase / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics
chemical_list: D016207:Cytokines; D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D020005:Propanols; D014764:Viral Proteins; C528900:glial fibrillary astrocytic protein, mouse; C006463:allyl alcohol; D002251:Carbon Tetrachloride; D013937:Thymidine Kinase; D015774:Ganciclovir