Transcript Profiling of High Fat Diet induced Obesity-prone and Obesity-resistant Rats
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE11492 | GEO | 2008/05/20
SECONDARY ACCESSION(S): PRJNA106305
REPOSITORIES: GEO
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Project description:Thiamine prevents diabetic complications, and its deficiency, resulting from mutation of thiamine transporter gene SLC19A2 has been linked to diabetes mellitus. We previously found that thiamine mitigates metabolic disorders in spontaneous hypertensive rats, harboring defects in glucose and fatty acid metabolism. The current study extends our hypothesis that that thiamine intervention may impact metabolic abnormalities in polyphagia-induced Otsuka Long-Evans Tokushima Fatty (OLETF) rats that lack functional cholecystokinin A receptors. Male OLETF rats exhibit progressive obesity and metabolic disorders similar to human metabolic syndrome. Male OLETF rats (4-week-old) were given free access to water containing either 0.2 % or 0 % of thiamine for 51 weeks. At the end of treatment, blood parameters and cardiac functions were analyzed. After sacrifice, the organs were removed and weights of organs and histological findings were evaluated. In addition, differential gene expression in the liver was analyzed. Thiamine intervention averted obesity, mainly resulting from reduction of visceral adiposity, and prevented metabolic disorders in OLETF rats. Histological evaluation revealed that thiamine alleviated adipocyte hypertrophy, steatosis in the liver, heart, and skeletal muscle, interstitial fibrosis in the heart and kidney, fatty degeneration in the pancreas, thickening of the basement membrane of vasculature, and glomerulopathy and mononuclear cell infiltration in the kidney. Cardiac and renal functions were preserved in thiamine treatment. Seventy-six genes showed at least two-fold difference in hepatic expression with thiamine treatment. Several of them participated in carbohydrate metabolism (Hk1, Pygb, Slc2a8, Rtn4, Rhbdl1, and Tspan8), lipid metabolism (Pla2g15, Por, and Lmf1), vascular physiology (S1pr1, Epha8, Rtn4, Slc7a13, Cdh15, Itga9, Cd151, Cd40lg, Nid1 and Lamb1), and carcinogenesis (Lmo7, Fgfr3, and Dmbt1). Modification of transcript expression well accorded with the findings of blood parameters and organ morphologies. Thiamine prevented polyphagia-induced obesity and metabolic and functional disorders in OLETF rats.
2009-12-07 | GSE19292 | GEO
Project description:An intrinsic property of the heart is an ability to rapidly and coordinately adjust flux through metabolic pathways in response to physiologic stimuli (termed metabolic flexibility). Cardiac metabolism also fluctuates across the 24-hr day, in association with diurnal sleep-wake and fasting-feeding cycles. Although loss of metabolic flexibility has been proposed to play a causal role in the pathogenesis of cardiac disease, it is currently unknown whether day-night variations in cardiac metabolism are altered during disease states. Here, we tested the hypothesis that diet-induced obesity disrupts cardiac “diurnal metabolic flexibility”, which is normalized by time-of-day-restricted feeding. Chronic high fat feeding (20-wk) induced obesity in mice, abolished diurnal rhythms in whole body metabolic flexibility, and increased markers of adverse cardiac remodeling (hypertrophy, fibrosis, and steatosis). RNAseq analysis revealed that 24-hr rhythms in the cardiac transcriptome were dramatically altered during obesity; only 22% of rhythmic transcripts in control hearts were unaffected by obesity. However, day-night differences in cardiac substrate oxidation were essentially identical in control and high fat fed mice. In contrast, day-night differences in both cardiac triglyceride synthesis and lipidome were abolished during obesity. Next, a subset of obese mice (induced by 18-wks ad libitum high fat feeding) were allowed access to the high fat diet only during the 12-hr dark (active) phase, for a 2-wk period. Dark phase restricted feeding partially restored whole body metabolic flexibility, as well as day-night differences in cardiac triglyceride synthesis and lipidome. Moreover, this intervention partially reversed adverse cardiac remodeling in obese mice. Collectively, these studies reveal diurnal metabolic inflexibility of the heart during obesity specifically for non-oxidative lipid metabolism (but not for substrate oxidation), and that restricting food intake to the active period partially reverses obesity-induced cardiac lipid metabolism abnormalities and adverse remodeling of the heart.
2021-04-09 | GSE171710 | GEO
Project description:It is well established that obese animals and humans show deficiencies in skeletal muscle content and metabolism. However, the mechanisms under how skeletal muscle metabolism affects systemic energy homeostasis is not well-defined. Here, we compared the skeletal muscle transcriptome from obese and lean controls in different species. We found an immune-responsive transcription factor interferon regulatory factor 4 (IRF4) was conserved to be increased in obese subjects from the three species (humans, non-human primates and mice). Thus, we demonstrated that loss of IRF4 specifically in skeletal muscle of mice showed protection against the metabolic effects of high-fat diet, with unexpected increased plasma and muscle branched-chain amino acid (BCAA) levels. Conversely, overexpression of skeletal muscle IRF4 caused obesity and insulin resistance, with decreased BCAA contents. Mechanistically, IRF4 can transcriptionally regulate branched-chain aminotransferase isozyme (BCATm) expression, and that overexpression of BCATm can reverse the effects of IRF4 depletion regarding to metabolic phenotypes. Further, we demonstrated ablation of IRF4 in skeletal muscle increased mitochondrial activity and glycogen synthesis in a BCATm- dependent manner. These studies establish IRF4 as a novel driver of BCAA metabolism via BCATm in skeletal muscle and may interpret the BCAAs paradox in obesity.
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Project description:Background and aims: Youth populations with overweight/obesity (OW/OB) exhibit heterogeneity in cardiometabolic health phenotypes (e.g. fasting glucose, serum triglycerides, etc.). The underling mechanisms for those differences are still unclear. This study aimed to analyze the whole blood transcriptome profile (RNA-seq) of children with metabolic healthy overweight/obesity (MHO) and metabolic unhealthy overweight/obesity (MUO) phenotypes. Methods: 27 children with OW/OB (10.14 ± 1.3 years, 59% boys) from the ActiveBrains project were included. MHO was defined as having none of the following criteria for metabolic syndrome: elevated fasting glucose, high serum triglycerides, low high-density lipoprotein cholesterol, and high systolic or diastolic blood pressure, while MUO was defined as presenting one or more of these criteria. Inflammatory markers interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), epidermal growth factor (EGF) and, vascular endothelial growth factor A (VEGF) were additionally determined. Total-blood RNA was analyzed by 5’-end RNA sequencing. Two different bioinformatics approaches were performed: 1) Differential gene expression analyses using Limma R/Bioconductor software package (analyses adjusted by sex and maturational status) and 2) weighted gene coexpression network analyses (WGCNA). Results: Children with MHO had lower values of pro-inflammatory cytokines TNF-α and IL-6 compared to MUO (p < 0.05). 40 genes were differentially expressed (FDR < 0.05) in children with MHO compared to MUO. WGCNA analysis identified 23 gene coexpression modules (i.e. clusters of genes) with low preservation (Zsummary < 2) in children with MHO compared to MUO. Differential and WGCNA gene expression patterns identified 32 genes linked to metabolism, mitochondrial and immune functions. Conclusions: Whole blood transcriptome analysis revealed a distinct pattern of gene expression in children with MHO compared to MUO children. The identified gene expression patterns related to metabolism, mitochondrial and immune functions can promote a better understanding of cardiovascular disease prognosis in individuals with MHO.
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Project description:Recent studies have identified intracellular metabolism as a fundamental determinant of macrophage function. In obesity, proinflammatory macrophages accumulate in adipose tissue and trigger chronic low-grade inflammation, that promotes the development of systemic insulin resistance, yet changes in their intracellular energy metabolism are currently unknown. We therefore set out to study metabolic signatures of adipose tissue macrophages (ATMs) in lean and obese conditions. F4/80-positive ATMs were isolated from obese vs lean mice. High-fat feeding of wild-type mice and myeloid-specific Hif1α-/- mice was used to examine the role of hypoxia-inducible factor-1α (HIF-1α) in ATMs part of obese adipose tissue. In vitro, bone marrow-derived macrophages were co-cultured with adipose tissue explants to examine adipose tissue-induced changes in macrophage phenotypes. Transcriptome analysis, real-time flux measurements, ELISA and several other approaches were used to determine the metabolic signatures and inflammatory status of macrophages. In addition, various metabolic routes were inhibited to determine their relevance for cytokine production. Transcriptome analysis and extracellular flux measurements of mouse ATMs revealed unique metabolic rewiring in obesity characterised by both increased glycolysis and oxidative phosphorylation. Similar metabolic activation of CD14+ cells in obese individuals was associated with diabetes outcome. These changes were not observed in peritoneal macrophages from obese vs lean mice and did not resemble metabolic rewiring in M1-primed macrophages. Instead, metabolic activation of macrophages was dose-dependently induced by a set of adipose tissue-derived factors that could not be reduced to leptin or lactate. Using metabolic inhibitors, we identified various metabolic routes, including fatty acid oxidation, glycolysis and glutaminolysis, that contributed to cytokine release by ATMs in lean adipose tissue. Glycolysis appeared to be the main contributor to the proinflammatory trait of macrophages in obese adipose tissue. HIF-1α, a key regulator of glycolysis, nonetheless appeared to play no critical role in proinflammatory activation of ATMs during early stages of obesity. Our results reveal unique metabolic activation of ATMs in obesity that promotes inflammatory cytokine release. Further understanding of metabolic programming in ATMs will most likely lead to novel therapeutic targets to curtail inflammatory responses in obesity.
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