Fat body-specific reduction of CTPS alleviates HFD-induced obesity
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ABSTRACT: High-fat diet (HFD)-induced obesity is a multi-factorial disease including genetic, physiological, behavioral, and environmental components. Drosophila has emerged as an effective metabolic disease model. Cytidine 5'-triphosphate synthase (CTPS) is a crucial enzyme for the de novo synthesis of CTP, governing the cellular level of CTP and phospholipid synthesis. CTPS has been found to form filaments known as cytoophidia, which are evolutionarily conserved in bacteria, archaea, and eukaryotes. Here, we show that CTPS functions in fat bodies to regulate body weight and starvation resistance in Drosophila. HFD-induced obesity enhances CTPS transcription and lengthens cytoophidia in larval adipocytes. CTPS depletion in the fat body prevented HFD-induced obesity, including body weight gain, adipocyte expansion, and lipid accumulation, by inhibiting the PI3K-Akt-SREBP axis. A dominant-negative form of CTPS also inhibits adipocyte expansion and down-regulates lipogenic genes. As a result, our findings not only establish a functional link between CTPS and lipid homeostasis but also highlight a potential role of CTPS manipulation in the treatment of HFD-induced obesity.
Project description:Toll-like receptors/Interleukin-1 receptor (IL-1R) signaling plays an important role in High-fat diet (HFD)-induced adipose tissue dysfunction contributing to obesity-associated metabolic syndromes. Here, we show an unconventional IL-1R-IRAKM (IL-1R-associated kinase M)-Slc25a1 signaling axis in adipocytes that reprograms lipogenesis to promote diet-induced obesity. Adipocyte-specific deficiency of IRAKM reduced HFD-induced body weight gain, increased whole body energy expenditure and improved insulin resistance, associated with decreased lipid accumulation and adipocyte cell sizes. IL-1β stimulation induced the translocation of IRAKM Myddosome to mitochondria to promote de novo lipogenesis in adipocytes. Mechanistically, IRAKM interacts with and phosphorylates mitochondrial citrate carrier Slc25a1 to promote IL-1β-induced mitochondrial citrate transport to cytosol and de novo lipogenesis. Moreover, IRAKM-Slc25a1 axis mediates IL-1β induced Pgc1a acetylation to regulate thermogenic gene expression in adipocytes. IRAKM kinase-inactivation also attenuated HFD-induced obesity. Taken together, our study suggests that the IL-1R-IRAKM-Slc25a1 signaling axis tightly links inflammation and adipocyte metabolism, indicating a novel therapeutic target for obesity.
Project description:From a long time ago, supplementation of fermented enzyme foods could have worked health effects on the body in the east nevertheless, only a few studies reported functions of them such as weight loss and metabolic syndrome. Thus, it is necessary to be verified whether supplementation of fermented enzyme foods can act in the body as a functional material. Therefore, we investigated the anti-obesity effects of fermented mixed grain with digestive enzymes (FMG) in high-fat diet induced mice. Sixty C57BL/6J mice were divided into six dietary groups and fed a normal diet (ND), a high-fat diet (HFD), Bacilus Coagulans group, steamed grain group, low-dose fermented mixed grain group(L-FMG), high-dose fermented mixed grain group (H-FMG) supplement for 12 weeks. After sacrificing, body weight and body fat mass in H-FMG group were significantly decreased compared to HFD group with a simultaneous decrease in plasma lipids. Also, H-FMG significantly decreased the blood glucose and improved the glucose tolerance compared to HFD group. Moreover high-dose FMG supplementation dramatically decreased the levels of inflammatory cytokines which secreted from adipocyte. Taken together, our findings suggest that H-FMG ameliorate high fat-diet induced obesity and its complication and could be used as a potential preventive agent for obesity.
Project description:Actin dynamics, mediated by various actin-binding proteins, plays an important role in adipocyte differentiation. We investigated the role of coactosin-like F-actin binding protein (Cotl1) in adipocyte differentiation in vitro and in vivo. Cotl1 expression level was increased during adipocyte differentiation in mouse 3T3-L1 cells and primary cultured adipose-derived stem cells (ADSCs) and during weight gain in adipose tissues. However, Cotl1 deficient in 3T3-L1 and ADSCs inhibited adipocyte differentiation, and Cotl1-/- mice displayed resistance to high-fat diet (HFD)-induced weight gain, hepatic steatosis and adipocyte enlargement compared to HFD-fed wild type (WT) mice. Ingenuity Pathway Analysis of RNA-sequencing in adipose tissues of HFD-WT and HFD-Cotl1-/- mice predicted complicated relationships between Cotl1, differentiation of adipocytes, obesity and organization of actin cytoskeleton. Particularly, peroxisome proliferator-activated receptor gamma (Pparg) emerged as a central player, with Cotl1 influencing Pparg expression, consequently regulating adipocyte differentiation. These findings suggest Cotl1 as a pivotal regulator of terminal adipocyte differentiation by modulating adipogenic genes.
Project description:Obesity has emerged as a major health risk on a global scale. Natural small molecules, such as hinokiflavone (HF) extracted from plants like cypress, exhibit diverse chemical structures and low synthesis costs. Using HFD-induced obese mice models, we found that HF suppresses obesity by inducing apoptosis in adipose tissue. Adipocyte apoptosis helps maintain tissue health by removing aging, damaged, or excess fat cells, crucial in preventing obesity and metabolic diseases. We found that HF can specifically bind to insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) to promote the stability of N6-methyladenosine (m6A) -modified Bim, inducing mitochondrial outer membrane permeabilization (MOMP). MOMP leads to Caspase9/3-mediated adipocyte mitochondrial pathway apoptosis, alleviating obesity induced by a high-fat diet. HF offers a controlled means of adipocyte apoptosis for weight loss. This study reveals the potential of small molecules like HF in developing new therapeutic approaches in drug development and biomedical research.
Project description:The diet induced obesity (DIO) mouse model has been widely used for obesity studies. Comparing to the composition of nutrients in the diet, the effects of storage conditions for high fat diet (HFD) on metabolic homeostasis have not been systemically investigated. In the current study, we tested the effects of HFD stored in different conditions and found the mice fed by HFD stored in the fridge (HFDfri) gained less weight than freezer (HFDfre). Further analysis revealed the changes of the relative abundance of medium chain triglyceride (MCT) in the HFDfri, which has much lower intestinal absorption rates, contributed to the body weight differences. In contrast, advanced liver damages and elevation of unfolded protein responses (UPR) was observed in the mice fed by the HFDfri. Depletion of UPR regulated gene Nnmt alleviated liver damages via inhibition of integrated stress response (ISR). Our study provided the initial evidence that HFD storage conditions have great impacts on both body weight changes and liver damages in the DIO model.
Project description:The diet induced obesity (DIO) mouse model has been widely used for obesity studies. Comparing to the composition of nutrients in the diet, the effects of storage conditions for high fat diet (HFD) on metabolic homeostasis have not been systemically investigated. In the current study, we tested the effects of HFD stored in different conditions and found the mice fed by HFD stored in the fridge (HFDfri) gained less weight than freezer (HFDfre). Further analysis revealed the changes of the relative abundance of medium chain triglyceride (MCT) in the HFDfri, which has much lower intestinal absorption rates, contributed to the body weight differences. In contrast, advanced liver damages and elevation of unfolded protein responses (UPR) was observed in the mice fed by the HFDfri. Depletion of UPR regulated gene Nnmt alleviated liver damages via inhibition of integrated stress response (ISR). Our study provided the initial evidence that HFD storage conditions have great impacts on both body weight changes and liver damages in the DIO model.
Project description:Despite wide efforts in the last decade, signaling aberrations associated with obesity remain enigmatic. Here, we carried out phosphoproteomic analysis of mouse white adipose tissues (WAT) upon low-fat diet (LFD) and high-fat diet (HFD) to dissect underlying molecular mechanisms of obesity. Of the 7696 phosphopeptides quantified, 191 proteins including various insulin-responsive proteins and metabolic enzymes functioning in lipid homeostasis, exhibited differential phosphorylation with high-fat feeding. Kinase predictions and integrated network analysis identified several deregulated kinase signaling pathways, and suggested possibilities of HFD-induced transcriptional rewiring. Further, functional validation of a novel HFD-responsive site on cytoplasmic acetyl-coA forming ACSS2 (S263) suggested that the phosphorylation is important in regulating insulin signaling and maintaining triglyceride levels. This study represents one of the first comprehensive phosphoproteome data in mouse obesity models, and describes a systems-level approach for identifying deregulated molecular events and potential therapeutic targets in the context of high-fat feeding and adipocyte perturbation.
Project description:The aim of this basic research is to test the efficacy of intranasal administration of Galanin-like Peptide (GALP) and its clinical application under the hypothesis that GALP prevents obesity in mice fed a high-fat diet (HFD). Focusing on the mechanism of regulation of lipid metabolism in peripheral tissues via the autonomic nervous system, we confirmed body weight changes after intranasal administration of GALP in diet-induced obesity (DIO) mice.
Project description:Oxidative stress in adipose tissue and liver has been linked to the development of obesity. NADPH oxidases (NOX) enzymes are a major source of reactive oxygen species (ROS). The current study was designed to determine if NOX2-generated ROS play a role in development of obesity and metabolic syndrome after high fat feeding. Wild type (WT) mice and mice lacking the cytosolic NOX2 activated protein p47phox (P47KO) were fed AIN-93G diets or high fat diets (HFD) containing 45% fat and 0.5% cholesterol for 13 weeks from weaning. Affymetrix array analysis revealed dramatically less expression of mRNA of genes linked to energy metabolism, adipocyte differentiation (PPARM-NM-3, Runx2) and fatty acid uptake (CD36, lipoprotein lipase) in fat pads from female HFD-P47KO mice compared to HFD-WT females. These data suggest that NOX2 is an important regulator of metabolic homeostasis and that NOX2-associated ROS plays an important role in development of diet-induced obesity particularly in the female fat pads from p47phox and wild type fed a high fat or control diet