title: Lack of the matricellular protein SPARC (secreted protein, acidic and rich in cysteine) attenuates liver fibrogenesis in mice.
abstract: BACKGROUND
  Secreted Protein, Acidic and Rich in Cysteine (SPARC) is a matricellular protein involved in many biological processes and found over-expressed in cirrhotic livers. By mean of a genetic approach we herein provide evidence from different in vivo liver disease models suggesting a profibrogenic role for SPARC.
  
  
  METHODS
  Two in vivo models of liver fibrosis, based on TAA administration and bile duct ligation, were developed on SPARC wild-type (SPARC(+/+)) and knock-out (SPARC(-/-)) mice. Hepatic SPARC expression was analyzed by qPCR. Fibrosis was assessed by Sirius Red staining, and the maturation state of collagen fibers was analyzed using polarized light. Necroinflammatory activity was evaluated by applying the Knodell score and liver inflammatory infiltration was characterized by immunohistochemistry. Hepatic stellate cell activation was assessed by α-SMA immunohistochemistry. In addition, pro-fibrogenic genes and inflammatory cytokines were measured by qPCR and/or ELISA. Liver gene expression profile was analyzed in SPARC(-/-) and SPARC(+/+) mice using Affymetrix Mouse Gene ST 1.0 array.
  
  
  RESULTS
  SPARC expression was found induced in fibrotic livers of mouse and human. SPARC(-/-) mice showed a reduction in the degree of inflammation, mainly CD4+ cells, and fibrosis. Consistently, collagen deposits and mRNA expression levels were decreased in SPARC(-/-) mice when compared to SPARC(+/+) mice; in addition, MMP-2 expression was increased in SPARC(-/-) mice. A reduction in the number of activated myofibroblasts was observed. Moreover, TGF-β1 expression levels were down-regulated in the liver as well as in the serum of TAA-treated knock-out animals. Ingenuity Pathway Analysis (IPA) analysis suggested several gene networks which might involve protective mechanisms of SPARC deficiency against liver fibrogenesis and a better established machinery to repair DNA and detoxify from external chemical stimuli.
  
  
  CONCLUSIONS
  Overall our data suggest that SPARC plays a significant role in liver fibrogenesis. Interventions to inhibit SPARC expression are suggested as promising approaches for liver fibrosis treatment.
authors: Gene Therapy Laboratory, School of Medicine, Austral University, Derqui-Pilar, Buenos Aires, Argentina.
authors: Catalina
authors: C
authors: Atorrasagasti
authors: Estanislao
authors: E
authors: Peixoto
authors: Jorge B
authors: JB
authors: Aquino
authors: Néstor
authors: N
authors: Kippes
authors: Mariana
authors: M
authors: Malvicini
authors: Laura
authors: L
authors: Alaniz
authors: Mariana
authors: M
authors: Garcia
authors: Flavia
authors: F
authors: Piccioni
authors: Esteban J
authors: EJ
authors: Fiore
authors: Juan
authors: J
authors: Bayo
authors: Ramón
authors: R
authors: Bataller
authors: Elizabeth
authors: E
authors: Guruceaga
authors: Fernando
authors: F
authors: Corrales
authors: Osvaldo
authors: O
authors: Podhajcer
authors: Guillermo
authors: G
authors: Mazzolini
mesh_terms: D000818:Animals; D001483:Base Sequence; D003094:Collagen / Q000378:metabolism; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D008103:Liver Cirrhosis / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020411:Oligonucleotide Array Sequence Analysis; D015676:Osteonectin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D017931:DNA Primers; D006023:Glycoproteins; D015676:Osteonectin; C578250:SPARC protein, mouse; D053773:Transforming Growth Factor beta1; D025521:Tumor Suppressor Proteins; D003094:Collagen