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TRAIL-producing NK cells contribute to liver injury and related fibrogenesis in the context of GNMT deficiency.

Fernández-Álvarez S, Gutiérrez-de Juan V, Zubiete-Franco I, Barbier-Torres L, Lahoz A, Parés A, Luka Z, Wagner C, Lu SC, Mato JM, Martínez-Chantar ML, Beraza N - Lab. Invest. (2014)

Bottom Line: Glycine-N-methyltransferase (GNMT) is essential to preserve liver homeostasis.The aim of our study is to elucidate the implication of TRAIL-producing NK cells in the progression of chronic liver injury and fibrogenesis.Overall, our work demonstrates that TRAIL-producing NK cells actively contribute to liver injury and further fibrogenesis in the pathological context of GNMT deficiency, a molecular scenario characteristic of chronic human liver disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Metabolomics, CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Derio, Spain.

ABSTRACT
Glycine-N-methyltransferase (GNMT) is essential to preserve liver homeostasis. Cirrhotic patients show low expression of GNMT that is absent in hepatocellular carcinoma (HCC) samples. Accordingly, GNMT deficiency in mice leads to steatohepatitis, fibrosis, cirrhosis, and HCC. Lack of GNMT triggers NK cell activation in GNMT(-/-) mice and depletion of TRAIL significantly attenuates acute liver injury and inflammation in these animals. Chronic inflammation leads to fibrogenesis, further contributing to the progression of chronic liver injury regardless of the etiology. The aim of our study is to elucidate the implication of TRAIL-producing NK cells in the progression of chronic liver injury and fibrogenesis. For this we generated double TRAIL(-/-)/GNMT(-/-) mice in which we found that TRAIL deficiency efficiently protected the liver against chronic liver injury and fibrogenesis in the context of GNMT deficiency. Next, to better delineate the implication of TRAIL-producing NK cells during fibrogenesis we performed bile duct ligation (BDL) to GNMT(-/-) and TRAIL(-/-)/GNMT(-/-) mice. In GNMT(-/-) mice, exacerbated fibrogenic response after BDL concurred with NK1.1(+) cell activation. Importantly, specific inhibition of TRAIL-producing NK cells efficiently protected GNMT(-/-) mice from BDL-induced liver injury and fibrogenesis. Finally, TRAIL(-/-)/GNMT(-/-) mice showed significantly less fibrosis after BDL than GNMT(-/-) mice further underlining the relevance of the TRAIL/DR5 axis in mediating liver injury and fibrogenesis in GNMT(-/-) mice. Finally, in vivo silencing of DR5 efficiently protected GNMT(-/-) mice from BDL-liver injury and fibrogenesis, overall underscoring the key role of the TRAIL/DR5 axis in promoting fibrogenesis in the context of absence of GNMT. Overall, our work demonstrates that TRAIL-producing NK cells actively contribute to liver injury and further fibrogenesis in the pathological context of GNMT deficiency, a molecular scenario characteristic of chronic human liver disease.

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In vivo silencing of DR5 in GNMT−/− mice attenuates fibrosis protecting the liver against BDL-induced injury(A) IF using αSMA Ab and Sirius Red staining and qPCR analysis of αSMA and Collagen 1A1 showed lower fibrosis in ShDR5/GNMT−/− mice. (B) Serum transaminases and bilirubin were lower in ShDR5/GNMT−/− mice compared to GNMT−/− mice after BDL. (C) H&E staining (left panels) and (D) further quantification (upper panel), (C) TUNEL assay (right panels) and (D) quantification of caspase-3 activity (lower panel) showed an obvious attenuation of both necrotic and apoptotic cell death in ShDR5/GNMT−/− mice. (E) Kaplan-Meier curve showing increased survival of ShDR5/GNMT−/− mice compared to GNMT−/− littermates. n = 5–7. *p< 0.05; **p< 0.01; ***P < 0.001 (GNMT−/−vs ShDR5/GNMT−/−). Error bars represent SD.
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Figure 7: In vivo silencing of DR5 in GNMT−/− mice attenuates fibrosis protecting the liver against BDL-induced injury(A) IF using αSMA Ab and Sirius Red staining and qPCR analysis of αSMA and Collagen 1A1 showed lower fibrosis in ShDR5/GNMT−/− mice. (B) Serum transaminases and bilirubin were lower in ShDR5/GNMT−/− mice compared to GNMT−/− mice after BDL. (C) H&E staining (left panels) and (D) further quantification (upper panel), (C) TUNEL assay (right panels) and (D) quantification of caspase-3 activity (lower panel) showed an obvious attenuation of both necrotic and apoptotic cell death in ShDR5/GNMT−/− mice. (E) Kaplan-Meier curve showing increased survival of ShDR5/GNMT−/− mice compared to GNMT−/− littermates. n = 5–7. *p< 0.05; **p< 0.01; ***P < 0.001 (GNMT−/−vs ShDR5/GNMT−/−). Error bars represent SD.

Mentions: Finally, silencing of DR5 in GNMT−/− mice confirmed the implication of the TRAIL/DR5 axis in mediating liver injury and further fibrogenesis. Thus, fibrosis was significantly reduced in ShDR5/GNMT−/− mice as we found lower αSMA levels and collagen deposition after BDL compared to GNMT−/− (Fig. 7A). Low fibrogenesis after DR5 silencing correlated with an overall significant improvement in the liver parenchyma of ShDR5/GNMT−/− mice that showed significantly lower AST, ALT and bilirubin serum levels after BDL (Fig. 7B). H&E staining, TUNEL assay, caspase-3 activity and a survival rate of 90% confirmed the liver protection exerted by silencing of DR5 in GNMT−/− mice (Fig. 7C–E).


TRAIL-producing NK cells contribute to liver injury and related fibrogenesis in the context of GNMT deficiency.

Fernández-Álvarez S, Gutiérrez-de Juan V, Zubiete-Franco I, Barbier-Torres L, Lahoz A, Parés A, Luka Z, Wagner C, Lu SC, Mato JM, Martínez-Chantar ML, Beraza N - Lab. Invest. (2014)

In vivo silencing of DR5 in GNMT−/− mice attenuates fibrosis protecting the liver against BDL-induced injury(A) IF using αSMA Ab and Sirius Red staining and qPCR analysis of αSMA and Collagen 1A1 showed lower fibrosis in ShDR5/GNMT−/− mice. (B) Serum transaminases and bilirubin were lower in ShDR5/GNMT−/− mice compared to GNMT−/− mice after BDL. (C) H&E staining (left panels) and (D) further quantification (upper panel), (C) TUNEL assay (right panels) and (D) quantification of caspase-3 activity (lower panel) showed an obvious attenuation of both necrotic and apoptotic cell death in ShDR5/GNMT−/− mice. (E) Kaplan-Meier curve showing increased survival of ShDR5/GNMT−/− mice compared to GNMT−/− littermates. n = 5–7. *p< 0.05; **p< 0.01; ***P < 0.001 (GNMT−/−vs ShDR5/GNMT−/−). Error bars represent SD.
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Figure 7: In vivo silencing of DR5 in GNMT−/− mice attenuates fibrosis protecting the liver against BDL-induced injury(A) IF using αSMA Ab and Sirius Red staining and qPCR analysis of αSMA and Collagen 1A1 showed lower fibrosis in ShDR5/GNMT−/− mice. (B) Serum transaminases and bilirubin were lower in ShDR5/GNMT−/− mice compared to GNMT−/− mice after BDL. (C) H&E staining (left panels) and (D) further quantification (upper panel), (C) TUNEL assay (right panels) and (D) quantification of caspase-3 activity (lower panel) showed an obvious attenuation of both necrotic and apoptotic cell death in ShDR5/GNMT−/− mice. (E) Kaplan-Meier curve showing increased survival of ShDR5/GNMT−/− mice compared to GNMT−/− littermates. n = 5–7. *p< 0.05; **p< 0.01; ***P < 0.001 (GNMT−/−vs ShDR5/GNMT−/−). Error bars represent SD.
Mentions: Finally, silencing of DR5 in GNMT−/− mice confirmed the implication of the TRAIL/DR5 axis in mediating liver injury and further fibrogenesis. Thus, fibrosis was significantly reduced in ShDR5/GNMT−/− mice as we found lower αSMA levels and collagen deposition after BDL compared to GNMT−/− (Fig. 7A). Low fibrogenesis after DR5 silencing correlated with an overall significant improvement in the liver parenchyma of ShDR5/GNMT−/− mice that showed significantly lower AST, ALT and bilirubin serum levels after BDL (Fig. 7B). H&E staining, TUNEL assay, caspase-3 activity and a survival rate of 90% confirmed the liver protection exerted by silencing of DR5 in GNMT−/− mice (Fig. 7C–E).

Bottom Line: Glycine-N-methyltransferase (GNMT) is essential to preserve liver homeostasis.The aim of our study is to elucidate the implication of TRAIL-producing NK cells in the progression of chronic liver injury and fibrogenesis.Overall, our work demonstrates that TRAIL-producing NK cells actively contribute to liver injury and further fibrogenesis in the pathological context of GNMT deficiency, a molecular scenario characteristic of chronic human liver disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Metabolomics, CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Derio, Spain.

ABSTRACT
Glycine-N-methyltransferase (GNMT) is essential to preserve liver homeostasis. Cirrhotic patients show low expression of GNMT that is absent in hepatocellular carcinoma (HCC) samples. Accordingly, GNMT deficiency in mice leads to steatohepatitis, fibrosis, cirrhosis, and HCC. Lack of GNMT triggers NK cell activation in GNMT(-/-) mice and depletion of TRAIL significantly attenuates acute liver injury and inflammation in these animals. Chronic inflammation leads to fibrogenesis, further contributing to the progression of chronic liver injury regardless of the etiology. The aim of our study is to elucidate the implication of TRAIL-producing NK cells in the progression of chronic liver injury and fibrogenesis. For this we generated double TRAIL(-/-)/GNMT(-/-) mice in which we found that TRAIL deficiency efficiently protected the liver against chronic liver injury and fibrogenesis in the context of GNMT deficiency. Next, to better delineate the implication of TRAIL-producing NK cells during fibrogenesis we performed bile duct ligation (BDL) to GNMT(-/-) and TRAIL(-/-)/GNMT(-/-) mice. In GNMT(-/-) mice, exacerbated fibrogenic response after BDL concurred with NK1.1(+) cell activation. Importantly, specific inhibition of TRAIL-producing NK cells efficiently protected GNMT(-/-) mice from BDL-induced liver injury and fibrogenesis. Finally, TRAIL(-/-)/GNMT(-/-) mice showed significantly less fibrosis after BDL than GNMT(-/-) mice further underlining the relevance of the TRAIL/DR5 axis in mediating liver injury and fibrogenesis in GNMT(-/-) mice. Finally, in vivo silencing of DR5 efficiently protected GNMT(-/-) mice from BDL-liver injury and fibrogenesis, overall underscoring the key role of the TRAIL/DR5 axis in promoting fibrogenesis in the context of absence of GNMT. Overall, our work demonstrates that TRAIL-producing NK cells actively contribute to liver injury and further fibrogenesis in the pathological context of GNMT deficiency, a molecular scenario characteristic of chronic human liver disease.

Show MeSH
Related in: MedlinePlus