Project description:Obesity is associated with insulin resistance, an important risk factor of type 2 diabetes, atherogenic dyslipidemia, nonalcoholic fatty liver disease (NAFLD), and cardiovascular disease. It has been postulated that accumulation of visceral adipose tissue (VAT) causes obesity-induced insulin resistance. The major purpose of this study was to test hypothesis that prophylactic VAT removal prevents the development of obesity-induced multi-organ (liver, skeletal muscle, adipose tissue) insulin resistance, dyslipidemia, and NAFLD. Accordingly, we surgically removed epididymal VAT from adult C57BL/6J mice and then evaluated in vivo and cellular metabolic pathways involved in glucose and lipid metabolism following feeding of chronic high-fat diet (HFD). We found that VAT removal prevented HFD-induced insulin resistance and markedly increased AKT-mediated insulin signaling in subcutaneous adipose tissue (SAT), liver, and skeletal muscle. VAT removal improved plasma lipid profiling and prevented obesity-induced NAFLD. In addition, VAT removal significantly increased circulating level of adiponectin, a key insulin-sensitizing adipokine, whereas it decreased interleukin-6, a pro-inflammatory adipokine. Data obtained from RNA-sequencing suggest that VAT removal prevents obesity-induced oxidative stress and inflammation in liver and SAT respectively. These findings demonstrate the causative role of VAT in the development of obesity and related systemic metabolic complications, such as insulin resistance, dyslipidemia, and NAFLD.
Project description:SCOPE: We investigated whether a novel dietary intervention consisting of an every-other-week calorie-restricted diet could prevent nonalcoholic fatty liver disease (NAFLD) development induced by a medium-fat (MF) diet. METHODS AND RESULTS: Nine-week-old male C57BL/6J mice received either a (i) control (C), (ii) 30E% calorie restricted (CR), (iii) MF (25E% fat), or (iv) intermittent (INT) diet, a diet alternating weekly between 40E% CR and an ad libitum MF diet until sacrifice at the age of 12 months. The metabolic, morphological, and molecular features of NAFLD were examined. The INT diet resulted in healthy metabolic and morphological features as displayed by the continuous CR diet: glucose tolerant, low hepatic triglyceride content, low plasma alanine aminotransferase. In contrast, the C- and MF-exposed mice with high body weight developed signs of NAFLD. However, the gene expression profiles of INT-exposed mice differed to those of CR-exposed mice and showed to be more similar with those of C- and MF-exposed mice with a comparable body weight. CONCLUSIONS: Our study reveals that the INT diet maintains metabolic health and reverses the adverse effects of the MF diet, thus effectively prevents the development of NAFLD in 12-month-old male C57BL/6J mice. Male C57Bl/6J mice were divided to 4 dietary intervention groups: Control (AIN-93W), 30% calorie restriction (CR; AIN-93W-CR), medium fat (MF; AIN-93W-MF; 25% energy from fat) and intermittent diet (INT; weekly alternating diet between AIN-93W-MF ad lib and 40% CR of AIN-93W). We performed various measurements on metabolic parameters and gene expression analysis on the liver. This entry represents the microarray data of the liver gene expression of each mouse.
Project description:To investigate the mechanism of hepatic Activin A and Gpnmb in NAFLD/NASH, we studied C57BL/6J mice on a FPC NASH diet and sugar water for 16 weeks, compared with standard chow diet, and used adeno-associated viral vectors with a liver-specific thyroxine binding globulin (TBG) promoter to express Activin A or GFP (control), or AAV8-H1-shRNA to knockdown of Gpnmb or scramble control in NAFLD/NASH liver. We then performed gene expression profiling analysis using data obtained from RNA-seq of 3 different livers in each group.
Project description:SCOPE: We investigated whether a novel dietary intervention consisting of an every-other-week calorie-restricted diet could prevent nonalcoholic fatty liver disease (NAFLD) development induced by a medium-fat (MF) diet. METHODS AND RESULTS: Nine-week-old male C57BL/6J mice received either a (i) control (C), (ii) 30E% calorie restricted (CR), (iii) MF (25E% fat), or (iv) intermittent (INT) diet, a diet alternating weekly between 40E% CR and an ad libitum MF diet until sacrifice at the age of 12 months. The metabolic, morphological, and molecular features of NAFLD were examined. The INT diet resulted in healthy metabolic and morphological features as displayed by the continuous CR diet: glucose tolerant, low hepatic triglyceride content, low plasma alanine aminotransferase. In contrast, the C- and MF-exposed mice with high body weight developed signs of NAFLD. However, the gene expression profiles of INT-exposed mice differed to those of CR-exposed mice and showed to be more similar with those of C- and MF-exposed mice with a comparable body weight. CONCLUSIONS: Our study reveals that the INT diet maintains metabolic health and reverses the adverse effects of the MF diet, thus effectively prevents the development of NAFLD in 12-month-old male C57BL/6J mice.
Project description:Inbred C57BL/6J mice differ in their susceptibility to diet-induced obesity. Comparison of the liver transcriptomes leads to genes that are involved in the development as well as the maintenance of fatty liver during the onset of obesity upon high fat diet feeding. Genes being upregulated in DIO responder can be seen as drivers of fatty liver development, while genes upregulated in DIO non-responder are most likely involved in the protection against fatty liver diseases.
Project description:Obesity alters circulating levels of pituitary hormones that govern hepatic immune-metabolic homeostasis, and dysregulation of which leads to NAFLD. Here, using diet induced obese and IRE1PKO mice, we uncovered an blunted unfolded protein response (UPR) but elevated inflammatory signatures in pituitary glands of obese mice. Mechanistically, we demonstrated that the pituitary IRE1alpha-XBP1 UPR branch is essential for protecting against pituitary endocrine defects and NAFLD progression in obesity.
Project description:Obesity alters circulating levels of pituitary hormones that govern hepatic immune-metabolic homeostasis, and dysregulation of which leads to NAFLD. Here, using diet induced obese mouse, we uncovered an blunted unfolded protein response (UPR) but elevated inflammatory signatures in pituitary glands of obese mice. Mechanistically, we demonstrated that the pituitary IRE1alpha-XBP1 UPR branch is essential for protecting against pituitary endocrine defects and NAFLD progression in obesity.
Project description:Obesity alters circulating levels of pituitary hormones that govern hepatic immune-metabolic homeostasis, and dysregulation of which leads to NAFLD. Here, using diet induced obese mouse and IRE1PKO mice, we uncovered an blunted unfolded protein response (UPR) but elevated inflammatory signatures in pituitary glands of obese mice. Mechanistically, we demonstrated that the pituitary IRE1alpha-XBP1 UPR branch is essential for protecting against pituitary endocrine defects and NAFLD progression in obesity.
Project description:Despite some success in identifying CNVs responsible for metabolic phenotypes including obesity and diabetes mellitus, there are as yet no data available to suggest whether or not CNVs might be involved in the etiology of the NAFLD spectrum. This report is a comprehensive analysis of copy number in Malaysian patients with NAFLD. Genomic DNA was extracted from blood obtained from patients with NAFLD and submitted for genome-wide analysis using aCGH
Project description:C57BL/6J mice were treated with natural compounds (naringenin and naringin). CD11b-postive myeloid cells were sorted from lymph nodes, and RNA was isolated from sorted cells.