Treatment with SRT1720, a SIRT1 activator, ameliorates fatty liver with reduced expression of lipogenic enzymes in MSG mice.

Abstract

Nonalcoholic fatty liver disease (NAFLD) is an abnormal liver metabolism often observed with insulin resistance and metabolic syndrome. Calorie restriction is a useful treatment for NAFLD and reportedly prolongs the life spans of several species in which sirtuin plays an important role. In this study, we examined whether the activation of SIRT1, a mammalian ortholog of sirtuin, may ameliorate the development of NAFLD. Monosodium glutamate (MSG) mice, which exhibited obesity and insulin resistance, were treated with SRT1720, a specific SIRT1 activator from the age of 6-16 wk. Sixteen-week-old MSG mice exhibited increased liver triglyceride content and elevated levels of aminotransferase. SRT1720 treatment significantly reduced these levels without affecting body weight or food intake. These results suggested that the administration of SRT1720 ameliorated the development of NAFLD in MSG mice. The expressions of lipogenic genes, such as sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase, and fatty acid synthase, and the serum lipid profiles, including free fatty acids, were elevated in MSG mice and were reduced by SRT1720 treatment. SRT1720 treatment also reduced the expressions of lipogenic genes in cultured HepG2 cells. Furthermore, SRT1720 treatment decreased the expressions of marker genes for oxidative stress and inflammatory cytokines in the liver of MSG mice. Taken together, SRT1720 treatment may reduce liver lipid accumulation, at least in part, by directly reducing the expressions of lipogenic genes. The reduction of oxidative stress and inflammation may also be involved in the amelioration of NAFLD.

• Authors: Yu Yamazaki, Isao Usui, Yukiko Kanatani, Yuji Matsuya, Koichi Tsuneyama, Shiho Fujisaka, Agussalim Bukhari, Hikari Suzuki, Satoko Senda, Shingo Imanishi, Kazuya Hirata, Manabu Ishiki, Ryuji Hayashi, Masaharu Urakaze, Hideo Nemoto, Masashi Kobayashi, Kazuyuki Tobe
• Journal: American journal of physiology. Endocrinology and metabolism (Am J Physiol Endocrinol Metab) Vol. 297 Issue 5 Pg. E1179-86 (Nov 2009) ISSN: 1522-1555 [Electronic] United States
• PMID: 19724016 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Heterocyclic Compounds, 4 or More Rings
• SRT1720
• Sirt1 protein, mouse
• Sirtuin 1
• Sodium Glutamate

Topics

• Animals
• Biotransformation (drug effects)
• Body Weight (drug effects)
• Cell Line, Tumor
• Eating (drug effects)
• Fatty Liver (chemically induced, drug therapy, enzymology)
• Hepatocytes (drug effects, metabolism)
• Heterocyclic Compounds, 4 or More Rings (pharmacology)
• Immunoblotting
• Immunoprecipitation
• Lipid Metabolism (drug effects)
• Lipogenesis (drug effects)
• Male
• Mice
• Mice, Inbred ICR
• Real-Time Polymerase Chain Reaction
• Sirtuin 1 (metabolism)
• Sodium Glutamate