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Lack of the matricellular protein SPARC (secreted protein, acidic and rich in cysteine) attenuates liver fibrogenesis in mice.

Atorrasagasti C, Peixoto E, Aquino JB, Kippes N, Malvicini M, Alaniz L, Garcia M, Piccioni F, Fiore EJ, Bayo J, Bataller R, Guruceaga E, Corrales F, Podhajcer O, Mazzolini G - PLoS ONE (2013)

Bottom Line: 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.Overall our data suggest that SPARC plays a significant role in liver fibrogenesis.

View Article: PubMed Central - PubMed

Affiliation: Gene Therapy Laboratory, School of Medicine, Austral University, Derqui-Pilar, Buenos Aires, Argentina.

ABSTRACT

Introduction: 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.

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Reduced maturation of SPARC−/− collagen fiber deposits.Representative pictures showing picrosirius red stained liver sections obtained from SPARC+/+ (A,C,E) or SPARC−/− (B,D,F) mice (n  = 6–8) observed under polarized light. Animals were left untreated (A,B), or were TAA-treated during 10 weeks (C,D) or subjected to BDL (E, F). Note the predominant mature and compacted nature of collagen fibers in wild-type treated mice and their immature and thin appearance in SPARC−/− animals. Original magnification 400X.
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pone-0054962-g006: Reduced maturation of SPARC−/− collagen fiber deposits.Representative pictures showing picrosirius red stained liver sections obtained from SPARC+/+ (A,C,E) or SPARC−/− (B,D,F) mice (n  = 6–8) observed under polarized light. Animals were left untreated (A,B), or were TAA-treated during 10 weeks (C,D) or subjected to BDL (E, F). Note the predominant mature and compacted nature of collagen fibers in wild-type treated mice and their immature and thin appearance in SPARC−/− animals. Original magnification 400X.

Mentions: In SPARC−/−, both TAA and BDL resulted in Sirius red stained fibers which in most cases could not be observed under polarized light due to their reduce thickness and immature state: in this setting they turned into green which make very difficult to distinguish them from the overall tissue (Figure 6). On the other hand, most of Sirius red stained collagen fibers observed in TAA and BDL SPARC+/+ mice could be also observed under polarized light, due to their increase in thickness and in maturation state: in this case they became orange to red in color after applying this procedure.


Lack of the matricellular protein SPARC (secreted protein, acidic and rich in cysteine) attenuates liver fibrogenesis in mice.

Atorrasagasti C, Peixoto E, Aquino JB, Kippes N, Malvicini M, Alaniz L, Garcia M, Piccioni F, Fiore EJ, Bayo J, Bataller R, Guruceaga E, Corrales F, Podhajcer O, Mazzolini G - PLoS ONE (2013)

Reduced maturation of SPARC−/− collagen fiber deposits.Representative pictures showing picrosirius red stained liver sections obtained from SPARC+/+ (A,C,E) or SPARC−/− (B,D,F) mice (n  = 6–8) observed under polarized light. Animals were left untreated (A,B), or were TAA-treated during 10 weeks (C,D) or subjected to BDL (E, F). Note the predominant mature and compacted nature of collagen fibers in wild-type treated mice and their immature and thin appearance in SPARC−/− animals. Original magnification 400X.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569438&req=5

pone-0054962-g006: Reduced maturation of SPARC−/− collagen fiber deposits.Representative pictures showing picrosirius red stained liver sections obtained from SPARC+/+ (A,C,E) or SPARC−/− (B,D,F) mice (n  = 6–8) observed under polarized light. Animals were left untreated (A,B), or were TAA-treated during 10 weeks (C,D) or subjected to BDL (E, F). Note the predominant mature and compacted nature of collagen fibers in wild-type treated mice and their immature and thin appearance in SPARC−/− animals. Original magnification 400X.
Mentions: In SPARC−/−, both TAA and BDL resulted in Sirius red stained fibers which in most cases could not be observed under polarized light due to their reduce thickness and immature state: in this setting they turned into green which make very difficult to distinguish them from the overall tissue (Figure 6). On the other hand, most of Sirius red stained collagen fibers observed in TAA and BDL SPARC+/+ mice could be also observed under polarized light, due to their increase in thickness and in maturation state: in this case they became orange to red in color after applying this procedure.

Bottom Line: 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.Overall our data suggest that SPARC plays a significant role in liver fibrogenesis.

View Article: PubMed Central - PubMed

Affiliation: Gene Therapy Laboratory, School of Medicine, Austral University, Derqui-Pilar, Buenos Aires, Argentina.

ABSTRACT

Introduction: 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.

Show MeSH
Related in: MedlinePlus