Insulin resistance and white adipose tissue inflammation are uncoupled in energetically challenged Fsp27-deficient mice.
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ABSTRACT:
SUBMITTER: Zhou L
PROVIDER: S-EPMC4354252 | biostudies-literature | 2015 Jan
REPOSITORIES: biostudies-literature
Publications
Insulin resistance and white adipose tissue inflammation are uncoupled in energetically challenged Fsp27-deficient mice.
Zhou Linkang L Park Shi-Young SY Xu Li L Xia Xiayu X Ye Jing J Su Lu L Jeong Kyeong-Hoon KH Hur Jang Ho JH Oh Hyunhee H Tamori Yoshikazu Y Zingaretti Cristina M CM Cinti Saverio S Argente Jesús J Yu Miao M Wu Lizhen L Ju Shenghong S Guan Feifei F Yang Hongyuan H Choi Cheol Soo CS Savage David B DB Li Peng P
Nature communications 20150107
Fsp27 is a lipid droplet-associated protein almost exclusively expressed in adipocytes where it facilitates unilocular lipid droplet formation. In mice, Fsp27 deficiency is associated with increased basal lipolysis, 'browning' of white fat and a healthy metabolic profile, whereas a patient with congenital CIDEC deficiency manifested an adverse lipodystrophic phenotype. Here we reconcile these data by showing that exposing Fsp27-null mice to a substantial energetic stress by crossing them with ob ...[more]
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Project description:Fsp27, a member of the Cide family proteins, was shown to localize to lipid droplet and promote lipid storage in adipocytes. We aimed to understand the biological role of Fsp27 in regulating adipose tissue differentiation, insulin sensitivity and energy balance. Fsp27(-/-) mice and Fsp27/lep double deficient mice were generated and we examined the adiposity, whole body metabolism, BAT and WAT morphology, insulin sensitivity, mitochondrial activity, and gene expression changes in these mouse strains. Furthermore, we isolated mouse embryonic fibroblasts (MEFs) from wildtype and Fsp27(-/-) mice, followed by their differentiation into adipocytes in vitro. We found that Fsp27 is expressed in both brown adipose tissue (BAT) and white adipose tissue (WAT) and its levels were significantly elevated in the WAT and liver of leptin-deficient ob/ob mice. Fsp27(-/-) mice had increased energy expenditure, lower levels of plasma triglycerides and free fatty acids. Furthermore, Fsp27(-/-)and Fsp27/lep double-deficient mice are resistant to diet-induced obesity and display increased insulin sensitivity. Moreover, white adipocytes in Fsp27(-/-) mice have reduced triglycerides accumulation and smaller lipid droplets, while levels of mitochondrial proteins, mitochondrial size and activity are dramatically increased. We further demonstrated that BAT-specific genes and key metabolic controlling factors such as FoxC2, PPAR and PGC1alpha were all markedly upregulated. In contrast, factors inhibiting BAT differentiation such as Rb, p107 and RIP140 were down-regulated in the WAT of Fsp27(-/-) mice. Remarkably, Fsp27(-/-) MEFs differentiated in vitro show many brown adipocyte characteristics in the presence of the thyroid hormone triiodothyronine (T3). Our data thus suggest that Fsp27 acts as a novel regulator in vivo to control WAT identity, mitochondrial activity and insulin sensitivity.
| S-EPMC2483355 | biostudies-literature
Project description:BACKGROUND: Brown and white adipose tissues (BAT and WAT) play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. The mouse Fat-Specific protein 27 (FSP27), a member of the cell death-inducing DFF45-like effector (CIDE) family, is expressed in both BAT and WAT and is associated with lipid droplets. Over-expression of FSP27 promotes lipid storage, whereas FSP27 deficient mice have improved insulin sensitivity and are resistant to diet-induced obesity. In addition, FSP27-deficient white adipocytes have reduced lipid storage, smaller lipid droplets, increased mitochondrial activity and a higher expression of several BAT-selective genes. To elucidate the molecular mechanism by which FSP27 controls lipid storage and gene expression in WAT and BAT, we systematically analyzed the gene expression profile of FSP27-deficient WAT by microarray analysis and compared the expression levels of a specific set of genes in WAT and BAT by semi-quantitative real-time PCR analysis. RESULTS: BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of FSP27-deficient mice. The expression of the BAT-selective genes was also dramatically up-regulated in the WAT of leptin/FSP27 double deficient mice. In addition, the expression levels of genes involved in multiple metabolic pathways, including oxidative phosphorylation, the TCA cycle, fatty acid synthesis and fatty acid oxidation, were increased in the FSP27-deficient WAT. In contrast, the expression levels for genes involved in extracellular matrix remodeling, the classic complement pathway and TGF-beta signaling were down-regulated in the FSP27-deficient WAT. Most importantly, the expression levels of regulatory factors that determine BAT identity, such as CEBP alpha/beta, PRDM16 and major components of the cAMP pathway, were markedly up-regulated in the WAT of FSP27-deficient mice. The expression levels of these regulatory factors were also up-regulated in leptin/FSP27 double deficient mice. Interestingly, distinct gene expression profiles were observed in the BAT of FSP27-deficient mice. Taken together, these data suggest that the WAT of FSP27-deficient mice have a gene expression profile similar to that of BAT. CONCLUSIONS: FSP27 acts as a molecular determinant that controls gene expression for a diversity of metabolic and signaling pathways and, in particular, the expression of regulatory factors, including CEBP alpha/beta, PRDM16 and components of the cAMP signaling pathway, that control the identity of WAT and BAT.
| S-EPMC3091643 | biostudies-literature
Project description:IntroductionAdipocyte size and body fat distribution are strongly linked to the metabolic complications of obesity. The aim of the present study was to test the plasticity of white adipose tissue in response to insulin deprivation and replacement. We have characterized the changes of adipose cell size repartition and gene expressions in type 1 diabetes Sprague-Dawley rats and type 1 diabetic supplemented with insulin.MethodsUsing streptozotocin (STZ)-induced diabetes, we induced rapid changes in rat adipose tissue weights to study the changes in the distribution of adipose cell sizes in retroperitoneal (rWAT), epididymal (eWAT) and subcutaneous adipose tissues (scWAT). Adipose tissue weights of type 1 diabetic rats were then rapidly restored by insulin supplementation. Cell size distributions were analyzed using multisizer IV (Beckman Coulter). Cell size changes were correlated to transcriptional regulation of genes coding for proteins involved in lipid and glucose metabolisms and adipocytokines.ResultsThe initial body weight of the rats was 465±5.2 g. Insulin privation was stopped when rats lost 100 g which induced reductions in fat mass of 68% for rWAT, 42% for eWAT and 59% for scWAT corresponding to decreased mode cell diameters by 31.1%, 20%, 25.3%, respectively. The most affected size distribution by insulin deprivation was observed in rWAT. The bimodal distribution of adipose cell sizes disappeared in response to insulin deprivation in rWAT and scWAT. The most important observation is that cell size distribution returned close to control values in response to insulin treatment. mRNAs coding for adiponectin, leptin and apelin were more stimulated in scWAT compared to other depots in diabetic plus insulin group.ConclusionFat depots have specific responses to insulin deprivation and supplementation. The results show that insulin is a major determinant of bimodal cell repartition in adipose tissues.
| S-EPMC4149534 | biostudies-literature
Project description:Background: Brown and white adipose tissues (BAT and WAT) play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. Fsp27 is expressed in both BAT and WAT and promotes lipid storage and the development of obesity and diabetes. In addition, Fsp27-deficient white adipocytes acquired certain BAT-like properties including reduced lipid droplet size and increased mitochondrial activity. Using microarray and semi-quantitative real-time PCR analyses, we systematically analyzed the gene expression profile in Fsp27-deficient WAT and BAT. Results: We observed that BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of Fsp27-/- mice. Expression levels of BAT-selective genes were also dramatically up-regulated in the WAT of leptin and Fsp27 double deficient mice. Furthermore, we observed that expression levels of genes in multiple metabolic pathways including oxidative phosphorylation, the TCA cycle and fatty acid synthesis and oxidation were increased in the Fsp27-/- WAT. In contrast, expression levels for extracellular matrix remodeling, the classic complement pathway and TGF-β signaling"were down-regulated in the WAT of Fsp27-/- mice. Most importantly, regulatory factors that determine BAT identity such as CEBPα/β, PRDM16 and major components in the cAMP pathway were markedly up-regulated in the WAT of Fsp27-/- mice. Interestingly, we observed distinct gene expression profiles in the BAT of Fsp27-/- mice. Conclusion: Our data suggest that Fsp27 acts at upstream to control gene expression of diverse pathways, in particular the expression of regulatory factors that determine the identity of BAT and WAT. Therefore, Fsp27 is an important molecular determinant for the identity of WAT, and loss of Fsp27 leads to the conversion of WAT to a BAT-like tissue.
2010-07-07 | GSE22693 | GEO
Project description:AIMS/HYPOTHESIS:Absent in melanoma 2 (AIM2) is a cytosolic sensor for double-stranded DNA and a tumour suppressor. Binding of double-stranded DNA to AIM2 forms the AIM2 inflammasome, leading to activation of caspase-1 and production of IL-1? and IL-18. Although inflammasome-independent effects of AIM2 have been reported, its role in energy metabolism is unknown. We aimed to evaluate the effect of AIM2 in energy metabolism and glucose homeostasis. METHODS:Male and female whole body Aim2 knockout (Aim2-/-) mice were used in the current study. Body weight, food intake, body composition, energy expenditure, fasting blood glucose levels, GTT and body temperature were measured at indicated time points. RNA sequencing was carried out on gonadal white adipose tissue (gWAT) in 14-month-old female mice. mRNA and protein levels in tissues were analysed by quantitative real-time PCR and immunoblot. Immune cell infiltration in gWAT was examined by flow cytometry. Stromal vascular fractions isolated from gWAT were used to investigate adipocyte differentiation. RESULTS:Male and female Aim2-/- mice were obese compared with wild-type controls from 7 weeks of age until 51 weeks of age, with increased adiposity in both subcutaneous and visceral fat depots. While there were no differences in food intake, Aim2-/- mice demonstrated decreased energy expenditure and impaired brown adipose tissue function compared with wild-type controls. Fasting glucose and insulin levels were elevated, and Aim2-/- mice were glucose intolerant on intraperitoneal GTT. RNA sequencing revealed marked upregulation of the IFN-inducible gene Ifi202b, which encodes protein 202 (p202) and elevated inflammatory signalling in gWAT of Aim2-/- mice. Increased infiltration of total and Ly6Clow monocytes was noted at 8 weeks of age in gWAT, before the onset of obesity and insulin resistance. Ifi202b knockdown blocked adipogenesis in stromal vascular fractions and reduced inflammation in bone marrow-derived macrophages, demonstrating a key role of p202 in mediating the increased adipogenesis and inflammation in Aim2-/- mice. CONCLUSIONS/INTERPRETATION:These results demonstrate a fundamental role for AIM2 in energy metabolism, inflammation and insulin resistance. Our studies establish a novel link between the innate immunity proteins, AIM2 and p202, and metabolism.
| S-EPMC7210565 | biostudies-literature
Project description:Fsp27 is a lipid droplet-associated protein almost exclusively expressed in adipocytes where it facilitates unilocular lipid droplet formation. In mice, Fsp27 deficiency is associated with increased basal lipolysis, browning of white fat and a healthy metabolic profile, whereas energetically challenged Fsp27 deficient mice (ob/ob/Fsp27 (-/-)) show dramatically reduced fat mass, hepatic steatosis and insulin resistance which represents a typical lipodystrophy phenotype. Here, we investigate the effect of Fsp27 depletion on the gene expression of gonadal white adipose tissue (GWAT) under normal or energetically challenged condition (Fsp27 (-/-) vs Wild type; ob/ob/Fsp27 (-/-) vs ob/ob). We systematically analyzed the change in signaling pathway in Fsp27 deficient mice. The raw data have been deposited into Gene Expression Omnibus (GEO): GSE59807 and GSE22693.
| S-EPMC4583699 | biostudies-literature
Project description:Obesity-associated low-grade inflammation at white adipose tissue (WAT) leads to metabolic defects. Sex steroid hormone estrogen may be protective against high-fat diet (HFD)-induced obesity and insulin resistance. This has been tested by many previous studies utilizing rodent models of ovariectomy (OVX) and/or treatment of estradiol (E2), the major biologically active form of estrogen. Body weight and adiposity are increased by OVX and reduced following E2 treatment, however. Thus, the protective roles of E2 may be secondary effects to the changes in body weight and adiposity. We hypothesize that E2 directly prevents inflammation and maintains insulin sensitivity in WAT independent of energy status using mice with similar body weights and adiposity.Four groups of female C57BL/6 mice were used, including sham-operated mice treated with vehicle for E2 and fed with either a low-fat diet (LFD; Sham-Veh-LFD) or a HFD (Sham-Veh-HFD), and HFD-fed OVX mice treated with either vehicle (OVX-Veh-HFD) or E2 (OVX-E2-HFD). Body weight and abdominal parametrial WAT mass, insulin signaling, and expression levels of genes related to low-grade inflammation in WAT were compared between these groups pair-fed with equal amounts of calories for a period of 4 days.Body weights and WAT mass were similar in all four groups. OVX-Veh-HFD mice had impaired insulin signaling associated with rapid activation of inflammation, whereas OVX-E2-HFD group maintained insulin sensitivity without showing inflammation in WAT.E2 directly contributed to the maintenance of insulin sensitivity during the early phase of development of metabolic dysfunction, possibly via preventing low-grade inflammation in WAT.
| S-EPMC4221806 | biostudies-literature
Project description:Obesity is characterized by visceral adipose tissue (AT) inflammation. Immunosuppressive regulatory T cells (Tregs), phagocytic M2-like macrophages, and innate lymphoid cells type 2 (ILC2) control lean AT inflammation to maintain systemic insulin sensitivity, while the loss of these cells in obesity leads to AT inflammation and insulin resistance (IR). The objective of this study was to determine if weight loss following obesity would correct AT inflammation and systemic metabolism. After six months of high fat diet (HFD) in male C57/Bl6 mice, flow analyses of epidydimal AT stromal vascular fraction (SVF) revealed depleted Tregs by 50%, doubling of CD8+ T cells, tripling of pro-inflammatory M1-like macrophages, and an 80% drop in ILC2 cells associated with changes in pro-inflammatory adipocyte and macrophage gene expression. Despite normalization of body weight, fat, and adipocyte size, mice ingesting 3 months of high-fat diet (HFD) followed by 3 months of chow-diet remained more insulin resistant and glucose intolerant than chow-fed animals. Adipocytes, AT Tregs, CD8+ T cells, ILC2 cells, and M1-like macrophages all failed to normalize with weight loss. Persistent AT inflammation contributes to the maintenance of IR despite body weight and fat normalization in previously obese mice. These findings highlight the importance of obesity prevention to avoid the consequences of "obesogenic memory."
| S-EPMC7409818 | biostudies-literature
Project description:Obesity is a major risk factor for insulin resistance and type 2 diabetes. In adipose tissue, obesity-mediated insulin resistance correlates with the accumulation of proinflammatory macrophages and inflammation. However, the causal relationship of these events is unclear. Here, we report that obesity-induced insulin resistance in mice precedes macrophage accumulation and inflammation in adipose tissue. Using a mouse model that combines genetically induced, adipose-specific insulin resistance (mTORC2-knockout) and diet-induced obesity, we found that insulin resistance causes local accumulation of proinflammatory macrophages. Mechanistically, insulin resistance in adipocytes results in production of the chemokine monocyte chemoattractant protein 1 (MCP1), which recruits monocytes and activates proinflammatory macrophages. Finally, insulin resistance (high homeostatic model assessment of insulin resistance [HOMA-IR]) correlated with reduced insulin/mTORC2 signaling and elevated MCP1 production in visceral adipose tissue from obese human subjects. Our findings suggest that insulin resistance in adipose tissue leads to inflammation rather than vice versa.
| S-EPMC5873875 | biostudies-other
Project description:Background: Brown and white adipose tissues (BAT and WAT) play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. Fsp27 is expressed in both BAT and WAT and promotes lipid storage and the development of obesity and diabetes. In addition, Fsp27-deficient white adipocytes acquired certain BAT-like properties including reduced lipid droplet size and increased mitochondrial activity. Using microarray and semi-quantitative real-time PCR analyses, we systematically analyzed the gene expression profile in Fsp27-deficient WAT and BAT. Results: We observed that BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of Fsp27-/- mice. Expression levels of BAT-selective genes were also dramatically up-regulated in the WAT of leptin and Fsp27 double deficient mice. Furthermore, we observed that expression levels of genes in multiple metabolic pathways including oxidative phosphorylation, the TCA cycle and fatty acid synthesis and oxidation were increased in the Fsp27-/- WAT. In contrast, expression levels for extracellular matrix remodeling, the classic complement pathway and TGF-β signaling"were down-regulated in the WAT of Fsp27-/- mice. Most importantly, regulatory factors that determine BAT identity such as CEBPα/β, PRDM16 and major components in the cAMP pathway were markedly up-regulated in the WAT of Fsp27-/- mice. Interestingly, we observed distinct gene expression profiles in the BAT of Fsp27-/- mice. Conclusion: Our data suggest that Fsp27 acts at upstream to control gene expression of diverse pathways, in particular the expression of regulatory factors that determine the identity of BAT and WAT. Therefore, Fsp27 is an important molecular determinant for the identity of WAT, and loss of Fsp27 leads to the conversion of WAT to a BAT-like tissue. Total RNAs were extracted from individual gonadal WAT of five pairs of 3-month-old wild-type and Fsp27-null male mice. Equal amounts of RNA from five pairs of mice with each genotype were pooled to form RNA pools (total 45 μg). Duplicate experiments were carried out.
2010-07-07 | E-GEOD-22693 | biostudies-arrayexpress