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The genetic architecture of NAFLD among inbred strains of mice.

Hui ST, Parks BW, Org E, Norheim F, Che N, Pan C, Castellani LW, Charugundla S, Dirks DL, Psychogios N, Neuhaus I, Gerszten RE, Kirchgessner T, Gargalovic PS, Lusis AJ - Elife (2015)

Bottom Line: Genome-wide association studies revealed three loci associated with hepatic TG accumulation.We hypothesize that Gde1 expression increases TG production by contributing to the production of glycerol-3-phosphate.Our multi-level data, including transcript levels, metabolite levels, and gut microbiota composition, provide a framework for understanding genetic and environmental interactions underlying hepatic steatosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine/Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.

ABSTRACT
To identify genetic and environmental factors contributing to the pathogenesis of non-alcoholic fatty liver disease, we examined liver steatosis and related clinical and molecular traits in more than 100 unique inbred mouse strains, which were fed a diet rich in fat and carbohydrates. A >30-fold variation in hepatic TG accumulation was observed among the strains. Genome-wide association studies revealed three loci associated with hepatic TG accumulation. Utilizing transcriptomic data from the liver and adipose tissue, we identified several high-confidence candidate genes for hepatic steatosis, including Gde1, a glycerophosphodiester phosphodiesterase not previously implicated in triglyceride metabolism. We confirmed the role of Gde1 by in vivo hepatic over-expression and shRNA knockdown studies. We hypothesize that Gde1 expression increases TG production by contributing to the production of glycerol-3-phosphate. Our multi-level data, including transcript levels, metabolite levels, and gut microbiota composition, provide a framework for understanding genetic and environmental interactions underlying hepatic steatosis.

No MeSH data available.


Related in: MedlinePlus

Effects of Gde1 knockdown in mice by adenoviral transduction.C57BL/6 mice were injected with Ad-shGde1 (1 × 109 pfu per mouse, i.v.) and fed with a HF/HS diet for 7 days. Control group received the same dose of Ad-Ctl. (A) Equal amounts of liver protein were loaded in each lane and Western-blotted using anti-GDE1 or anti-actin antibody. (B) Comparison of Gde1 mRNA levels between Gde1-knockdown mice and the control mice. (C–E) Liver lipids were extracted and quantified: triglyceride (TG), TC, and phospholipids (PL). (F) Expression of lipogenic genes was measured by qPCR and normalized to the level of the housekeeping gene 36B4. Results are presented as mean + SD (n = 11–12) * denotes p < 0.05 and ** denotes p < 0.01.DOI:http://dx.doi.org/10.7554/eLife.05607.020
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fig9: Effects of Gde1 knockdown in mice by adenoviral transduction.C57BL/6 mice were injected with Ad-shGde1 (1 × 109 pfu per mouse, i.v.) and fed with a HF/HS diet for 7 days. Control group received the same dose of Ad-Ctl. (A) Equal amounts of liver protein were loaded in each lane and Western-blotted using anti-GDE1 or anti-actin antibody. (B) Comparison of Gde1 mRNA levels between Gde1-knockdown mice and the control mice. (C–E) Liver lipids were extracted and quantified: triglyceride (TG), TC, and phospholipids (PL). (F) Expression of lipogenic genes was measured by qPCR and normalized to the level of the housekeeping gene 36B4. Results are presented as mean + SD (n = 11–12) * denotes p < 0.05 and ** denotes p < 0.01.DOI:http://dx.doi.org/10.7554/eLife.05607.020

Mentions: Complementary to the overexpression studies, we also knocked down hepatic Gde1 expression in vivo by adenoviral expression of shRNA. The virus dose and diet treatment were identical to that described above for the overexpression studies. Both Gde1 protein and mRNA levels were ∼75% decreased in the mice received adenoviral shRNA (Figure 9A,B). In contrast to the overexpression studies, knockdown of Gde1 led to a significant decrease in hepatic TG content (Figure 9C, p = 0.011), whereas TC and phospholipid levels were not different from the control group (Figure 9D,E). Similarly, expression of lipogenic genes (Fasn, Dgat2, and Gpd1) was increased in Gde1-knockdown livers (Figure 9F). These findings support a causal role for Gde1 in hepatic steatosis under the chromosome 7 locus.10.7554/eLife.05607.020Figure 9.Effects of Gde1 knockdown in mice by adenoviral transduction.


The genetic architecture of NAFLD among inbred strains of mice.

Hui ST, Parks BW, Org E, Norheim F, Che N, Pan C, Castellani LW, Charugundla S, Dirks DL, Psychogios N, Neuhaus I, Gerszten RE, Kirchgessner T, Gargalovic PS, Lusis AJ - Elife (2015)

Effects of Gde1 knockdown in mice by adenoviral transduction.C57BL/6 mice were injected with Ad-shGde1 (1 × 109 pfu per mouse, i.v.) and fed with a HF/HS diet for 7 days. Control group received the same dose of Ad-Ctl. (A) Equal amounts of liver protein were loaded in each lane and Western-blotted using anti-GDE1 or anti-actin antibody. (B) Comparison of Gde1 mRNA levels between Gde1-knockdown mice and the control mice. (C–E) Liver lipids were extracted and quantified: triglyceride (TG), TC, and phospholipids (PL). (F) Expression of lipogenic genes was measured by qPCR and normalized to the level of the housekeeping gene 36B4. Results are presented as mean + SD (n = 11–12) * denotes p < 0.05 and ** denotes p < 0.01.DOI:http://dx.doi.org/10.7554/eLife.05607.020
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493743&req=5

fig9: Effects of Gde1 knockdown in mice by adenoviral transduction.C57BL/6 mice were injected with Ad-shGde1 (1 × 109 pfu per mouse, i.v.) and fed with a HF/HS diet for 7 days. Control group received the same dose of Ad-Ctl. (A) Equal amounts of liver protein were loaded in each lane and Western-blotted using anti-GDE1 or anti-actin antibody. (B) Comparison of Gde1 mRNA levels between Gde1-knockdown mice and the control mice. (C–E) Liver lipids were extracted and quantified: triglyceride (TG), TC, and phospholipids (PL). (F) Expression of lipogenic genes was measured by qPCR and normalized to the level of the housekeeping gene 36B4. Results are presented as mean + SD (n = 11–12) * denotes p < 0.05 and ** denotes p < 0.01.DOI:http://dx.doi.org/10.7554/eLife.05607.020
Mentions: Complementary to the overexpression studies, we also knocked down hepatic Gde1 expression in vivo by adenoviral expression of shRNA. The virus dose and diet treatment were identical to that described above for the overexpression studies. Both Gde1 protein and mRNA levels were ∼75% decreased in the mice received adenoviral shRNA (Figure 9A,B). In contrast to the overexpression studies, knockdown of Gde1 led to a significant decrease in hepatic TG content (Figure 9C, p = 0.011), whereas TC and phospholipid levels were not different from the control group (Figure 9D,E). Similarly, expression of lipogenic genes (Fasn, Dgat2, and Gpd1) was increased in Gde1-knockdown livers (Figure 9F). These findings support a causal role for Gde1 in hepatic steatosis under the chromosome 7 locus.10.7554/eLife.05607.020Figure 9.Effects of Gde1 knockdown in mice by adenoviral transduction.

Bottom Line: Genome-wide association studies revealed three loci associated with hepatic TG accumulation.We hypothesize that Gde1 expression increases TG production by contributing to the production of glycerol-3-phosphate.Our multi-level data, including transcript levels, metabolite levels, and gut microbiota composition, provide a framework for understanding genetic and environmental interactions underlying hepatic steatosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine/Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.

ABSTRACT
To identify genetic and environmental factors contributing to the pathogenesis of non-alcoholic fatty liver disease, we examined liver steatosis and related clinical and molecular traits in more than 100 unique inbred mouse strains, which were fed a diet rich in fat and carbohydrates. A >30-fold variation in hepatic TG accumulation was observed among the strains. Genome-wide association studies revealed three loci associated with hepatic TG accumulation. Utilizing transcriptomic data from the liver and adipose tissue, we identified several high-confidence candidate genes for hepatic steatosis, including Gde1, a glycerophosphodiester phosphodiesterase not previously implicated in triglyceride metabolism. We confirmed the role of Gde1 by in vivo hepatic over-expression and shRNA knockdown studies. We hypothesize that Gde1 expression increases TG production by contributing to the production of glycerol-3-phosphate. Our multi-level data, including transcript levels, metabolite levels, and gut microbiota composition, provide a framework for understanding genetic and environmental interactions underlying hepatic steatosis.

No MeSH data available.


Related in: MedlinePlus