Adenovirus-mediated inhibition of SPARC attenuates liver fibrosis in rats

ALEJANDRA CAMINO; CATALINA ATORRASAGASTI; DANIELA MACCIO; FEDERICO PRADA; EDGARDO SALVATIERRA; MIGUEL RIZZO,; LAURA ALANIZ; JORGE AQUINO; OSVALDO PODHAJCER; MARCELO SILVA; GUILLERMO MAZZOLINI

JOURNAL OF GENE MEDICINE

John Wiley & Sons

Año: 2008 vol. 10 p. 993 - 1004

1099-498X

Background The interaction between fibrogenic cells and extracellularmatrix plays a role in liver fibrosis, yet the mechanisms are largely unknown.Secreted protein, acidic and rich in cysteine (SPARC) is a matricellularglycoprotein that is expressed by hepatic stellate cells and is overexpressedin fibrotic livers. We investigated the in vivo role of SPARC in experimentallyinduced liver fibrosis in rats.Methods A recombinant adenovirus carrying antisense SPARC wasconstructed (AdasSPARC). Advanced liver fibrosis was induced in Sprague-Dawley rats by prolonged intraperitoneal administration of thioacetamide.Animals received injections of AdasSPARC or Adβgal (control adenovirus)via the tail vein and directly into the liver 1 week after the first dose. Thepathological changes in liver tissues and indices of fibrosis were assessed ateight weeks. Expression of SPARC, transforming growth factor (TGF)-β andα-smooth muscle actin were evaluated by quantitative real-time polymerasechain reaction, western blotting, enzyme-linked immunosorbent assay andimmunohistochemistry.Results Hepatic SPARC expression significantly increased during thedevelopment of liver fibrosis. AdasSPARC markedly attenuated thedevelopment of hepatic fibrosis in rats treated with thiocetamide, asassessed by decreased collagen deposition, lower hepatic content ofhydroxyproline and less advanced morphometric stage of fibrosis. AdasSPARCtreatment reduced inflammatory activity (Knodell score) and suppressedtransdifferentiation of hepatic stellate cell to the myofibroblasts likephenotype in vivo. Furthermore, in vitro inhibition of SPARC on hepaticstellate cells decreases the production of TGF-β.