Dataset Information

Mice with an Oncogenic HRAS Mutation are Resistant to High-Fat Diet-Induced Obesity and Exhibit Impaired Hepatic Energy Homeostasis.

ABSTRACT: Costello syndrome is a "RASopathy" that is characterized by growth retardation, dysmorphic facial appearance, hypertrophic cardiomyopathy and tumor predisposition. >80% of patients with Costello syndrome harbor a heterozygous germline G12S mutation in HRAS. Altered metabolic regulation has been suspected because patients with Costello syndrome exhibit hypoketotic hypoglycemia and increased resting energy expenditure, and their growth is severely retarded. To examine the mechanisms of energy reprogramming by HRAS activation in vivo, we generated knock-in mice expressing a heterozygous Hras G12S mutation (Hras^G12S/+ mice) as a mouse model of Costello syndrome. On a high-fat diet, Hras^G12S/+ mice developed a lean phenotype with microvesicular hepatic steatosis, resulting in early death compared with wild-type mice. Under starvation conditions, hypoketosis and elevated blood levels of long-chain fatty acylcarnitines were observed, suggesting impaired mitochondrial fatty acid oxidation. Our findings suggest that the oncogenic Hras mutation modulates energy homeostasis in vivo.

SUBMITTER: Oba D

PROVIDER: S-EPMC5828294 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

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Mice with an Oncogenic HRAS Mutation are Resistant to High-Fat Diet-Induced Obesity and Exhibit Impaired Hepatic Energy Homeostasis.

Oba Daiju D Inoue Shin-Ichi SI Miyagawa-Tomita Sachiko S Nakashima Yasumi Y Niihori Tetsuya T Yamaguchi Seiji S Matsubara Yoichi Y Aoki Yoko Y

EBioMedicine 20171206

Costello syndrome is a "RASopathy" that is characterized by growth retardation, dysmorphic facial appearance, hypertrophic cardiomyopathy and tumor predisposition. >80% of patients with Costello syndrome harbor a heterozygous germline G12S mutation in HRAS. Altered metabolic regulation has been suspected because patients with Costello syndrome exhibit hypoketotic hypoglycemia and increased resting energy expenditure, and their growth is severely retarded. To examine the mechanisms of energy repr ...[more]

PMID: 29254681

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Project description:BackgroundHexabromocyclododecane (HBCD) is an additive flame retardant used in the textile industry and in polystyrene foam manufacturing. Because of its lipophilicity and persistency, HBCD accumulates in adipose tissue and thus has the potential of causing metabolic disorders through disruption of lipid and glucose homeostasis. However, the association between HBCD and obesity remains unclear.ObjectivesWe investigated whether exposure to HBCD contributes to initiation and progression of obesity and related metabolic dysfunction in mice fed a normal diet (ND) or a high-fat diet (HFD).MethodsMale C57BL/6J mice were fed a HFD (62.2 kcal% fat) or a ND and treated orally with HBCD (0, 1.75, 35, or 700 μg/kg body weight) weekly from 6 to 20 weeks of age. We examined body weight, liver weight, blood biochemistry, histopathological changes, and gene expression profiles in the liver and adipose tissue.ResultsIn HFD-fed mice, body and liver weight were markedly increased in mice treated with the high (700 μg/kg) and medium (35 μg/kg) doses of HBCD compared with vehicle. This effect was more prominent in the high-dose group. These increases were paralleled by increases in random blood glucose and insulin levels and enhancement of microvesicular steatosis and macrophage accumulation in adipose tissue. HBCD-treated HFD-fed mice also had increased mRNA levels of Pparg (peroxisome proliferator-activated receptor-γ) in the liver and decreased mRNA levels of Glut4 (glucose transporter 4) in adipose tissue compared with vehicle-treated HFD-fed mice.ConclusionsOur findings suggest that HBCD may contribute to enhancement of diet-induced body weight gain and metabolic dysfunction through disruption of lipid and glucose homeostasis, resulting in accelerated progression of obesity.CitationYanagisawa R, Koike E, Win-Shwe TT, Yamamoto M, Takano H. 2014. Impaired lipid and glucose homeostasis in hexabromocyclododecane-exposed mice fed a high-fat diet. Environ Health Perspect 122:277-283; http://dx.doi.org/10.1289/ehp.1307421.

Dataset Information

Mice with an Oncogenic HRAS Mutation are Resistant to High-Fat Diet-Induced Obesity and Exhibit Impaired Hepatic Energy Homeostasis.

Publications

Mice with an Oncogenic HRAS Mutation are Resistant to High-Fat Diet-Induced Obesity and Exhibit Impaired Hepatic Energy Homeostasis.

Similar Datasets

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