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AAV8-mediated Sirt1 gene transfer to the liver prevents high carbohydrate diet-induced nonalcoholic fatty liver disease.

Vilà L, Elias I, Roca C, Ribera A, Ferré T, Casellas A, Lage R, Franckhauser S, Bosch F - Mol Ther Methods Clin Dev (2014)

Bottom Line: The protein deacetylase Sirtuin1 (SIRT1), which is activated by CR, increases catabolic metabolism and decreases lipogenesis and inflammation, both involved in the development of NAFLD.Here we show that adeno-associated viral vectors of serotype 8 (AAV8)-mediated liver-specific Sirt1 gene transfer prevents the development of NAFLD induced by a high carbohydrate (HC) diet.AAV8-Sirt1-treated mice showed improved insulin sensitivity, increased oxidative capacity in skeletal muscle and reduced white adipose tissue inflammation.

View Article: PubMed Central - PubMed

Affiliation: Center of Animal Biotechnology and Gene Therapy, School of Veterinary Medicine, Universitat Autònoma de Barcelona , Bellaterra, Spain ; Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona , Bellaterra, Spain ; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) , Barcelona, Spain.

ABSTRACT
Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disease worldwide, and evidence suggests that it promotes insulin resistance and type 2 diabetes. Caloric restriction (CR) is the only available strategy for NAFLD treatment. The protein deacetylase Sirtuin1 (SIRT1), which is activated by CR, increases catabolic metabolism and decreases lipogenesis and inflammation, both involved in the development of NAFLD. Here we show that adeno-associated viral vectors of serotype 8 (AAV8)-mediated liver-specific Sirt1 gene transfer prevents the development of NAFLD induced by a high carbohydrate (HC) diet. Long-term hepatic SIRT1 overexpression led to upregulation of key hepatic genes involved in β-oxidation, prevented HC diet-induced lipid accumulation and reduced liver inflammation. AAV8-Sirt1-treated mice showed improved insulin sensitivity, increased oxidative capacity in skeletal muscle and reduced white adipose tissue inflammation. Moreover, HC feeding induced leptin resistance, which was also attenuated in AAV8-Sirt1-treated mice. Therefore, AAV-mediated gene transfer to overexpress SIRT1 specifically in the liver may represent a new gene therapy strategy to counteract NAFLD and related diseases such as type 2 diabetes.

No MeSH data available.


Related in: MedlinePlus

AAV8-Sirt1–treated mice showed reduced hepatic lipid accumulation when fed a high carbohydrate diet. (a) Representative sections of the liver from AAV8-Null- and AAV8-Sirt1–treated mice fed with a high carbohydrate (HC) diet stained with hematoxylin-eosin. Original magnification ×100. (b) Liver triglyceride content. (c) Liver weight (d) Expression levels of Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Nuclear respiratory factor 1 (Nrf1), Medium-chain acyl-Coenzyme A dehydrogenase (Acadm), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Carnitinepalmitoyltransferase 2 (Cpt2), Sirtuin 6 (Sirt6), Sirtuin 3 (Sirt3), and Sirtuin 4 (Sirt4) were analyzed in the liver of AAV8-Null and AAV8-Sirt1 mice. (e) Representative western blot and quantification of hepatic PPARGC1a protein levels of AAV8-Null and AAV8-Sirt1 mice, using tubulin as a loading control. All analyses were performed after 15 weeks on HC diet. Data represent the mean ± SEM of at least four animals per group. *P < 0.05 and **P < 0.01 versus AAV8-Null.
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fig2: AAV8-Sirt1–treated mice showed reduced hepatic lipid accumulation when fed a high carbohydrate diet. (a) Representative sections of the liver from AAV8-Null- and AAV8-Sirt1–treated mice fed with a high carbohydrate (HC) diet stained with hematoxylin-eosin. Original magnification ×100. (b) Liver triglyceride content. (c) Liver weight (d) Expression levels of Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Nuclear respiratory factor 1 (Nrf1), Medium-chain acyl-Coenzyme A dehydrogenase (Acadm), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Carnitinepalmitoyltransferase 2 (Cpt2), Sirtuin 6 (Sirt6), Sirtuin 3 (Sirt3), and Sirtuin 4 (Sirt4) were analyzed in the liver of AAV8-Null and AAV8-Sirt1 mice. (e) Representative western blot and quantification of hepatic PPARGC1a protein levels of AAV8-Null and AAV8-Sirt1 mice, using tubulin as a loading control. All analyses were performed after 15 weeks on HC diet. Data represent the mean ± SEM of at least four animals per group. *P < 0.05 and **P < 0.01 versus AAV8-Null.

Mentions: To examine whether an increase in hepatic SIRT1 expression may protect against the development of NAFLD, AAV8-Sirt1- and AAV8-Null–treated mice were fed a HC diet during 15 weeks. Histological analysis showed that the deposition of fat in the liver was increased in mice fed a HC diet compared with mice fed a standard (STD) diet (Supplementary Figure S2a). The injection of AAV8-Null vectors did not affect the degree of accumulation of lipids in the liver of animals fed a HC diet (Supplementary Figure S3a). However, this lipid accumulation was greatly attenuated following hepatic gene transfer with AAV8-Sirt1 (Figure 2a). Indeed, the triglyceride content was reduced by 43% in the liver of AAV8-Sirt1–treated mice in comparison with AAV8-Null mice (Figure 2b), in parallel with a decrease of 17% in the weight of the organ (Figure 2c). HC diet induces lipid accumulation in the liver through increased lipogenesis and reduced β-oxidation (Supplementary Figure S2a,b).24 No differences were observed in the hepatic expression levels of lipogenic genes such as Sterol regulatory element binding transcription factor 1c (Srebf1) and Fatty acid synthase (Fasn) in mice that received AAV8-Sirt1 vectors (Data not shown). However, the liver expression of genes key to lipid oxidation and mitochondrial biogenesis such as Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Sirtuin 6 (Sirt6) and Sirtuin 3 (Sirt3) was increased in treated animals (Figure 2d). A slight upregulation of Nuclear respiratory factor 1 (Nrf1) and Carnitinepalmitoyltransferase 2 (Cpt2) mRNA was also observed in mice treated with AAV8-Sirt1 and fed a HC diet (Figure 2d). Furthermore, the content of PPARGC1A protein was also increased in the liver following AAV8-Sirt1 treatment (Figure 2e). Thus, these data suggest that the reduction in the hepatic accumulation of lipids could result from increased β-oxidation in the liver of AAV8-Sirt1–treated mice.


AAV8-mediated Sirt1 gene transfer to the liver prevents high carbohydrate diet-induced nonalcoholic fatty liver disease.

Vilà L, Elias I, Roca C, Ribera A, Ferré T, Casellas A, Lage R, Franckhauser S, Bosch F - Mol Ther Methods Clin Dev (2014)

AAV8-Sirt1–treated mice showed reduced hepatic lipid accumulation when fed a high carbohydrate diet. (a) Representative sections of the liver from AAV8-Null- and AAV8-Sirt1–treated mice fed with a high carbohydrate (HC) diet stained with hematoxylin-eosin. Original magnification ×100. (b) Liver triglyceride content. (c) Liver weight (d) Expression levels of Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Nuclear respiratory factor 1 (Nrf1), Medium-chain acyl-Coenzyme A dehydrogenase (Acadm), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Carnitinepalmitoyltransferase 2 (Cpt2), Sirtuin 6 (Sirt6), Sirtuin 3 (Sirt3), and Sirtuin 4 (Sirt4) were analyzed in the liver of AAV8-Null and AAV8-Sirt1 mice. (e) Representative western blot and quantification of hepatic PPARGC1a protein levels of AAV8-Null and AAV8-Sirt1 mice, using tubulin as a loading control. All analyses were performed after 15 weeks on HC diet. Data represent the mean ± SEM of at least four animals per group. *P < 0.05 and **P < 0.01 versus AAV8-Null.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig2: AAV8-Sirt1–treated mice showed reduced hepatic lipid accumulation when fed a high carbohydrate diet. (a) Representative sections of the liver from AAV8-Null- and AAV8-Sirt1–treated mice fed with a high carbohydrate (HC) diet stained with hematoxylin-eosin. Original magnification ×100. (b) Liver triglyceride content. (c) Liver weight (d) Expression levels of Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Nuclear respiratory factor 1 (Nrf1), Medium-chain acyl-Coenzyme A dehydrogenase (Acadm), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Carnitinepalmitoyltransferase 2 (Cpt2), Sirtuin 6 (Sirt6), Sirtuin 3 (Sirt3), and Sirtuin 4 (Sirt4) were analyzed in the liver of AAV8-Null and AAV8-Sirt1 mice. (e) Representative western blot and quantification of hepatic PPARGC1a protein levels of AAV8-Null and AAV8-Sirt1 mice, using tubulin as a loading control. All analyses were performed after 15 weeks on HC diet. Data represent the mean ± SEM of at least four animals per group. *P < 0.05 and **P < 0.01 versus AAV8-Null.
Mentions: To examine whether an increase in hepatic SIRT1 expression may protect against the development of NAFLD, AAV8-Sirt1- and AAV8-Null–treated mice were fed a HC diet during 15 weeks. Histological analysis showed that the deposition of fat in the liver was increased in mice fed a HC diet compared with mice fed a standard (STD) diet (Supplementary Figure S2a). The injection of AAV8-Null vectors did not affect the degree of accumulation of lipids in the liver of animals fed a HC diet (Supplementary Figure S3a). However, this lipid accumulation was greatly attenuated following hepatic gene transfer with AAV8-Sirt1 (Figure 2a). Indeed, the triglyceride content was reduced by 43% in the liver of AAV8-Sirt1–treated mice in comparison with AAV8-Null mice (Figure 2b), in parallel with a decrease of 17% in the weight of the organ (Figure 2c). HC diet induces lipid accumulation in the liver through increased lipogenesis and reduced β-oxidation (Supplementary Figure S2a,b).24 No differences were observed in the hepatic expression levels of lipogenic genes such as Sterol regulatory element binding transcription factor 1c (Srebf1) and Fatty acid synthase (Fasn) in mice that received AAV8-Sirt1 vectors (Data not shown). However, the liver expression of genes key to lipid oxidation and mitochondrial biogenesis such as Peroxisome proliferative activated receptor, gamma, coactivator 1 α (Ppargc1α), Long-chain acyl-Coenzyme A dehydrogenase (Acadl), Very long chain acyl-CoA dehydrogenase (Acadvl), Sirtuin 6 (Sirt6) and Sirtuin 3 (Sirt3) was increased in treated animals (Figure 2d). A slight upregulation of Nuclear respiratory factor 1 (Nrf1) and Carnitinepalmitoyltransferase 2 (Cpt2) mRNA was also observed in mice treated with AAV8-Sirt1 and fed a HC diet (Figure 2d). Furthermore, the content of PPARGC1A protein was also increased in the liver following AAV8-Sirt1 treatment (Figure 2e). Thus, these data suggest that the reduction in the hepatic accumulation of lipids could result from increased β-oxidation in the liver of AAV8-Sirt1–treated mice.

Bottom Line: The protein deacetylase Sirtuin1 (SIRT1), which is activated by CR, increases catabolic metabolism and decreases lipogenesis and inflammation, both involved in the development of NAFLD.Here we show that adeno-associated viral vectors of serotype 8 (AAV8)-mediated liver-specific Sirt1 gene transfer prevents the development of NAFLD induced by a high carbohydrate (HC) diet.AAV8-Sirt1-treated mice showed improved insulin sensitivity, increased oxidative capacity in skeletal muscle and reduced white adipose tissue inflammation.

View Article: PubMed Central - PubMed

Affiliation: Center of Animal Biotechnology and Gene Therapy, School of Veterinary Medicine, Universitat Autònoma de Barcelona , Bellaterra, Spain ; Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona , Bellaterra, Spain ; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) , Barcelona, Spain.

ABSTRACT
Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disease worldwide, and evidence suggests that it promotes insulin resistance and type 2 diabetes. Caloric restriction (CR) is the only available strategy for NAFLD treatment. The protein deacetylase Sirtuin1 (SIRT1), which is activated by CR, increases catabolic metabolism and decreases lipogenesis and inflammation, both involved in the development of NAFLD. Here we show that adeno-associated viral vectors of serotype 8 (AAV8)-mediated liver-specific Sirt1 gene transfer prevents the development of NAFLD induced by a high carbohydrate (HC) diet. Long-term hepatic SIRT1 overexpression led to upregulation of key hepatic genes involved in β-oxidation, prevented HC diet-induced lipid accumulation and reduced liver inflammation. AAV8-Sirt1-treated mice showed improved insulin sensitivity, increased oxidative capacity in skeletal muscle and reduced white adipose tissue inflammation. Moreover, HC feeding induced leptin resistance, which was also attenuated in AAV8-Sirt1-treated mice. Therefore, AAV-mediated gene transfer to overexpress SIRT1 specifically in the liver may represent a new gene therapy strategy to counteract NAFLD and related diseases such as type 2 diabetes.

No MeSH data available.


Related in: MedlinePlus