scholarly journals The autophagy inducer spermidine protects against metabolic dysfunction during overnutrition

2021 ◽  
Author(s):  
Chen-Yu Liao ◽  
Oona M P Kummert ◽  
Amanda M Bair ◽  
Nora Alavi ◽  
Josef Alavi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Visceral Fat ◽  
Energy Homeostasis ◽  
Subcutaneous Fat ◽  
Metabolic Effects ◽  
Daily Injection ◽  
Metabolic Dysfunction ◽  
Diet Induced Obesity ◽  
Old Mice ◽  
Fgf21 Expression

Abstract Autophagy, a process catabolizing intracellular components to maintain energy homeostasis, impacts aging and metabolism. Spermidine, a natural polyamine and autophagy activator, extends lifespan across a variety of species, including mice. In addition to protecting cardiac and liver tissue, spermidine also affects adipose tissue through unexplored mechanisms. Here, we examined spermidine in the links between autophagy and systemic metabolism. Consistently, daily injection of spermidine delivered even at late life is sufficient to cause a trend in lifespan extension in wild type mice. We further found that spermidine has minimal metabolic effects in young and old mice under normal nutrition. However, spermidine counteracts HFD (high-fat diet)-induced obesity by increasing lipolysis in visceral fat. Mechanistically, spermidine increases the hepatokine FGF21 expression in liver without reducing food intake. Spermidine also modulates FGF21 in adipose tissues, elevating FGF21 expression in subcutaneous fat, but reducing it in visceral fat. Despite this, FGF21 is not required for spermidine action, since Fgf21  -/- mice were still protected from HFD. Furthermore, the enhanced lipolysis by spermidine was also independent of autophagy in adipose tissue, given that adipose-specific autophagy deficient (Beclin-1  flox/+  Fabp4-cre) mice remained spermidine-responsive under HFD. Our results suggest that the metabolic effects of spermidine occurs through systemic changes in metabolism, involving multiple mechanistic pathways.

scholarly journals Unique Genetic and Histological Signatures of Mouse Pericardial Adipose Tissue

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1855
Author(s):  
A. Al-Dibouni ◽  
R. Gaspar ◽  
S. Ige ◽  
S. Boateng ◽  
F. R. Cagampang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Visceral Fat ◽  
Uncoupling Protein ◽  
Subcutaneous Fat ◽  
Metabolic Dysfunction ◽  
High Fat ◽  
Adipose Depot ◽  
Pericardial Adipose Tissue ◽  
Visceral Adipose ◽  
Adipose Tissue Depot

Obesity is a major risk factor for a plethora of metabolic disturbances including diabetes and cardiovascular disease. Accumulating evidence is showing that there is an adipose tissue depot-dependent relationship with obesity-induced metabolic dysfunction. While some adipose depots, such as subcutaneous fat, are generally metabolically innocuous, others such as visceral fat, are directly deleterious. A lesser known visceral adipose depot is the pericardial adipose tissue depot. We therefore set out to examine its transcriptional and morphological signature under chow and high-fat fed conditions, in comparison with other adipose depots, using a mouse model. Our results revealed that under chow conditions pericardial adipose tissue has uncoupling-protein 1 gene expression levels which are significantly higher than classical subcutaneous and visceral adipose depots. We also observed that under high-fat diet conditions, the pericardial adipose depot exhibits greatly upregulated transcript levels of inflammatory cytokines. Our results collectively indicate, for the first time, that the pericardial adipose tissue possesses a unique transcriptional and histological signature which has features of both a beige (brown fat-like) but also pro-inflammatory depot, such as visceral fat. This unique profile may be involved in metabolic dysfunction associated with obesity.

scholarly journals Visceral obesity: A new risk factor for stone disease

2015 ◽  
Vol 9 (11-12) ◽  
pp. 795 ◽  
Author(s):  
Ilker Akarken ◽  
Hüseyin Tarhan ◽  
Rahmi Gökhan Ekin ◽  
Özgür Çakmak ◽  
Gökhan Koç ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Adipose Tissue ◽  
Kidney Stones ◽  
Visceral Fat ◽  
Subcutaneous Adipose Tissue ◽  
Subcutaneous Fat ◽  
Stone Disease ◽  
Flank Pain ◽  
Fat Tissue ◽  
Subcutaneous Adipose

Introduction: We examined the relationship between stone disease and the amount of visceral adipose tissue measured with unenhanced computed tomography (CT).Methods: We included 149 patients with complaints of flank pain and kidney stones detected by CT, from August 2012 to April 2013. In addition, as the control group we included 139 healthy individuals, with flank pain within the same time period, with no previous history of urological disease and no current kidney stones identified by CT. Patients were analyzed for age, gender, body mass index, amount of visceral and subcutaneous adipose tissue, and serum level of low-density lipoprotein and triglyceride.Results: There were no differences between groups in terms of gender and age (p = 0.27 and 0.06, respectively). Respective measurements for the stone and control groups for body mass index were 29.1 and 27.6 kg/m2; for visceral fat measurement 186.0 and 120.2 cm2; and for subcutaneous fat measurements 275.9 and 261.9 cm2 (p = 0.01; 0.01 and 0.36, respectively). Using multivariate analysis, the following factors were identified as increasing the risk of kidney stone formation: hyperlipidemia (p = 0.003), hypertension (p = 0.001), and ratio of visceral fat tissue to subcutaneous fat tissue (p = 0.01). Our study has its limitations, including its retrospective nature, its small sample size, possible selection bias, and missing data. The lack of stone composition data is another major limitation of our study.Conclusion: The ratio of visceral to subcutaneous adipose tissue, in addition to obesity, hyperlipidemia, and hypertension, was identified as an emerging factor in the formation of kidney stones.

scholarly journals Update on FXR Biology: Promising Therapeutic Target?

2018 ◽  
Vol 19 (7) ◽  
pp. 2069 ◽  
Author(s):  
Chang Han
Keyword(s):  
Therapeutic Target ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Current Knowledge ◽  
Farnesoid X Receptor ◽  
Metabolic Effects ◽  
Metabolic Dysfunction ◽  
Energy Status ◽  
Safety Issues ◽  
Attractive Therapeutic Target

Farnesoid X receptor (FXR), a metabolic nuclear receptor, plays critical roles in the maintenance of systemic energy homeostasis and the integrity of many organs, including liver and intestine. It regulates bile acid, lipid, and glucose metabolism, and contributes to inter-organ communication, in particular the enterohepatic signaling pathway, through bile acids and fibroblast growth factor-15/19 (FGF-15/19). The metabolic effects of FXR are also involved in gut microbiota. In addition, FXR has various functions in the kidney, adipose tissue, pancreas, cardiovascular system, and tumorigenesis. Consequently, the deregulation of FXR may lead to abnormalities of specific organs and metabolic dysfunction, allowing the protein as an attractive therapeutic target for the management of liver and/or metabolic diseases. Indeed, many FXR agonists have been being developed and are under pre-clinical and clinical investigations. Although obeticholic acid (OCA) is one of the promising candidates, significant safety issues have remained. The effects of FXR modulation might be multifaceted according to tissue specificity, disease type, and/or energy status, suggesting the careful use of FXR agonists. This review summarizes the current knowledge of systemic FXR biology in various organs and the gut–liver axis, particularly regarding the recent advancement in these fields, and also provides pharmacological aspects of FXR modulation for rational therapeutic strategies and novel drug development.

Abstract 374: Interleukin-19: A Novel Pro-Angiogenic and Anti-Inflammatory Adipokine

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Christine Vrakas ◽  
Sheri E Keleman ◽  
Rosario Scalia ◽  
Michael V Autieri
Keyword(s):  
Adipose Tissue ◽  
Visceral Fat ◽  
Subcutaneous Fat ◽  
Chow Diet ◽  
Vascular Cells ◽  
Regulatory Factor ◽  
Normal Chow ◽  
Gene Regulatory ◽  
Anti Inflammatory ◽  
Normal Chow Diet

Uncontrolled inflammation leads to many of the chronic diseases associated with obesity. Due to a lack of oxygen in the tissue, expanding adipose tissue becomes hypoxic and pro-inflammatory. Adipocytes release pro-angiogenic factors in an effort to restore blood flow to the tissue. Presently, little is known about the potential for endogenously expressed anti-inflammatory cytokines to attenuate inflammation and also provide pro-angiogenic effects. IL-19 is uniquely anti-inflammatory, pro-angiogenic and is both expressed by and targets various cells types. IL-19 expression in adipocytes and stromal vascular cells is increased in visceral compared to subcutaneous fat, and is also increased in visceral fat on high fat diet (HFD) compared to normal chow diet. There is no known mechanism to explain the role of IL-19 in adipose tissue expansion, and we hypothesized that IL-19 may have pro-angiogenic and anti-inflammatory properties in expanding adipose tissue. We have identified a gene regulatory factor, Interleukin Enhancer-Binding Factor 3 (ILF3) that is induced in adipocytes and stromal vascular cells by HFD and IL-19 treatment. We found that both IL-19 and VEGF induce ILF3 expression in cultured human endothelial cells (hECs). Proliferation is significantly reduced when ILF3 is knocked down using siRNA in hECs. Furthermore, when ILF3 is knocked down and hECs are stimulated with VEGF several angiogenic cytokines are also decreased. Through immunohistochemistry we found that ILF3 translocates from the nucleus to the cytoplasm in visceral fat of C57BL/6 mice fed a HFD, and remains in the nucleus when fed a normal chow diet. In summary IL-19 may be a unique HFD responsive adipokine functioning to reduce inflammation and increase angiogenesis in expanding adipose tissue. The angiogenic function of IL-19 may work through induction of the gene regulatory factor, ILF3.

Abstract 5822: Atherosclerotic Plaque Inflammation Synchronize With Inflammatory Activity OF Visceral Fat

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Eung Ju Kim ◽  
Hong Seog Seo ◽  
Sungeun Kim ◽  
Jin Oh Na ◽  
Jae Hyoung Park ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Atherosclerotic Plaque ◽  
Visceral Adipose Tissue ◽  
Visceral Fat ◽  
Subcutaneous Fat ◽  
Fdg Uptake ◽  
Coronary Syndrome ◽  
Significant Difference ◽  
Plaque Inflammation ◽  
Visceral Adipose

Background: Visceral adipose tissue is thought to confer increased cardiovascular risk through leukocyte infiltration and increased adipose macrophage activity. Previous positron emission tomography (PET) studies using fluorodeoxyglucose (FDG) demonstrated that increased FDG uptake could reflect the severity of inflammation in atherosclerotic plaque. We hypothesized that active atherosclerotic change in the major arteries would accompany increased inflammation within visceral fat and it could be detected in humans using combined FDG PET/computed tomography (CT). Methods: We observed 44 consecutive subjects with cardiovascular disease. For all of them, an one-hour PET/CT (from brain to foot) was performed after injection of FDG (370–555 MBq). FDG uptake in the aorta or its major branches was evaluated visually and semiquantitatively. Maximal standard uptake values (SUV) of the highest regions of interest were calculated in the subcutaneous fat and visceral fat area, separately. Results: Significant FDG uptake in the arterial wall was noted in 21 patients (plaque positive; PP group), all of whom have experienced acute cardiovascular events (acute coronary syndrome or ischemic stroke) within a week. The other 23 patients (plaque negative; PN group) had chronic stable angina or asymptomatic carotid stenosis. Visceral fat SUV was significantly higher as compared to subcutaneous fat SUV (0.49± 0.15 vs. 0.15± 0.05, p< 0.001) in PP group, whereas there was no significant difference in PN group (0.18± 0.07 vs. 0.16± 0.03, p= 0.622). When we compared two groups, PP group showed higher visceral fat SUV than PN group (p< 0.001). In terms of subcutaneous fat SUV, the results were similar in two groups (p= 0.773). Conclusions: We demonstrated that atherosclerotic plaque inflammation was associated with increased inflammation within visceral fat. Our results need to be confirmed by comparison with histologic or other imaging findings. Further evaluation to determine whether metabolic activity of visceral adipose tissue is a marker or mediator of vascular inflammation is also needed.

Adiponectin is required to mediate rimonabant-induced improvement of insulin sensitivity but not body weight loss in diet-induced obese mice

2009 ◽  
Vol 296 (4) ◽  
pp. R929-R935 ◽  
Author(s):  
Stéphanie Migrenne ◽  
Amélie Lacombe ◽  
Anne-Laure Lefèvre ◽  
Marie-Pierre Pruniaux ◽  
Etienne Guillot ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Energy Homeostasis ◽  
Hepatic Glucose Production ◽  
Body Weight Loss ◽  
Metabolic Effects ◽  
Wild Type ◽  
High Fat ◽  
Wild Type Littermate

The increase in adiponectin levels in obese patients with untreated dyslipidemia and its mRNA expression in adipose tissue of obese animals are one of the most interesting consequences of rimonabant treatment. Thus, part of rimonabant's metabolic effects could be related to an enhancement of adiponectin secretion and its consequence on the modulation of insulin action, as well as energy homeostasis. The present study investigated the effects of rimonabant in adiponectin knockout mice (Ad−/−) exposed to diet-induced obesity conditions. Six-week-old Ad−/− male mice and their wild-type littermate controls (Ad+/+) were fed a high-fat diet for 7 mo. During the last month, animals were administered daily either with vehicle or rimonabant by mouth (10 mg/kg). High-fat feeding induced weight gain by about 130% in both wild-type and Ad−/− mice. Obesity was associated with hyperinsulinemia and insulin resistance. Treatment with rimonabant led to a significant and similar decrease in body weight in both Ad+/+ and Ad−/− mice compared with vehicle-treated animals. In addition, rimonabant significantly improved insulin sensitivity in Ad+/+ mice compared with Ad+/+ vehicle-treated mice by decreasing hepatic glucose production and increasing glucose utilization index in both visceral and subcutaneous adipose tissue. In contrast, rimonabant failed to improve insulin sensitivity in Ad−/− mice, despite the loss in body weight. Rimonabant's effect on body weight appeared independent of the adiponectin pathway, whereas adiponectin seems required to mediate rimonabant-induced improvement of insulin sensitivity in rodents.

scholarly journals Minor role of mature adipocyte mineralocorticoid receptor in high-fat diet-induced obesity

2018 ◽  
Vol 239 (2) ◽  
pp. 229-240 ◽  
Author(s):  
A Feraco ◽  
A Armani ◽  
R Urbanet ◽  
A Nguyen Dinh Cat ◽  
V Marzolla ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Mouse Model ◽  
High Fat Diet ◽  
Mineralocorticoid Receptor ◽  
Metabolic Effects ◽  
Minor Role ◽  
High Fat ◽  
Mature Adipocyte ◽  
Diet Induced Obesity ◽  
Significant Difference

Obesity is a major risk factor that contributes to the development of cardiovascular disease and type 2 diabetes. Mineralocorticoid receptor (MR) expression is increased in the adipose tissue of obese patients and several studies provide evidence that MR pharmacological antagonism improves glucose metabolism in genetic and diet-induced mouse models of obesity. In order to investigate whether the lack of adipocyte MR is sufficient to explain these beneficial metabolic effects, we generated a mouse model with inducible adipocyte-specific deletion of Nr3c2 gene encoding MR (adipo-MRKO). We observed a significant, yet not complete, reduction of Nr3c2 transcript and MR protein expression in subcutaneous and visceral adipose depots of adipo-MRKO mice. Notably, only mature adipocyte fraction lacks MR, whereas the stromal vascular fraction maintains normal MR expression in our mouse model. Adipo-MRKO mice fed a 45% high-fat diet for 14 weeks did not show any significant difference in body weight and fat mass compared to control littermates. Glucose and insulin tolerance tests revealed that mature adipocyte MR deficiency did not improve insulin sensitivity in response to a metabolic homeostatic challenge. Accordingly, no significant changes were observed in gene expression profile of adipogenic and inflammatory markers in adipose tissue of adipo-MRKO mice. Moreover, pharmacological MR antagonism in mature primary murine adipocytes, which differentiated ex vivo from WT mice, did not display any effect on adipokine expression. Taken together, these data demonstrate that the depletion of MR in mature adipocytes displays a minor role in diet-induced obesity and metabolic dysfunctions.

TWEAK prevents TNF-α-induced insulin resistance through PP2A activation in human adipocytes

2013 ◽  
Vol 305 (1) ◽  
pp. E101-E112 ◽  
Author(s):  
Ana Vázquez-Carballo ◽  
Victòria Ceperuelo-Mallafré ◽  
Matilde R. Chacón ◽  
Elsa Maymó-Masip ◽  
Margarita Lorenzo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Signaling ◽  
Visceral Fat ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Metabolic Effects ◽  
Human Adipocytes ◽  
Fat Depots ◽  
Tnf Α

Visceral fat is strongly associated with insulin resistance. Obesity-associated adipose tissue inflammation and inflammatory cytokine production are considered key mediators of insulin signaling inhibition. TWEAK is a relatively new member of the TNF cytokine superfamily, which can exist as full length membrane-associated (mTWEAK) and soluble (sTWEAK) isoforms. Although TWEAK has been shown to have important functions in chronic inflammatory diseases its physiological role in adipose tissue remains unresolved. In this study, we explore the molecular mechanisms involved in the modulation of TNF-α-induced effects on insulin sensitivity by sTWEAK in a human visceral adipose cell line and also in primary human adipocytes obtained from visceral fat depots. Our data reveal that sTWEAK ameliorates TNF-α-induced insulin resistance on glucose uptake, GLUT4 translocation and insulin signaling without affecting other metabolic effects of TNF-α such as lipolysis or apoptotis. Co-immunoprecipitation experiments in adipose cells revealed that pretreatment with sTWEAK specifically inhibits TRAF2 association with TNFR1, but not with TNFR2, which mediates insulin resistance. However, sTWEAK does not affect other downstream molecules activated by TNF-α, such as TAK1. Rather, sTWEAK abolishes the stimulatory effect of TNF-α on JNK1/2, which is directly involved in the development of insulin resistance. This is associated with an increase in PP2A activity upon sTWEAK treatment. Silencing of the PP2A catalytic subunit gene overcomes the dephosphorylation effect of sTWEAK on JNK1/2, pointing to PP2A as a relevant mediator of sTWEAK-induced JNK inactivation. Overall, our data reveal a protective role of TWEAK in glucose homeostasis and identify PP2A as a new driver in the modulation of TNF-α signaling by sTWEAK.

scholarly journals Thrombospondin-1 regulates adiposity and metabolic dysfunction in diet-induced obesity enhancing adipose inflammation and stimulating adipocyte proliferation

2013 ◽  
Vol 305 (3) ◽  
pp. E439-E450 ◽  
Author(s):  
Ping Kong ◽  
Carlos Gonzalez-Quesada ◽  
Na Li ◽  
Michele Cavalera ◽  
Dong-Wook Lee ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Weight Gain ◽  
Fatty Acid Uptake ◽  
Cytokine Signaling ◽  
Vascular Density ◽  
Acid Uptake ◽  
Metabolic Dysfunction ◽  
Diet Induced Obesity ◽  
Obesity And Diabetes

As a typical matricellular protein, thrombospondin (TSP)-1, binds to the structural matrix and regulates cellular behavior by modulating growth factor and cytokine signaling. Obesity and diabetes are associated with marked upregulation of TSP-1 in adipose tissue. We hypothesized that endogenous TSP-1 may play an important role in the pathogenesis of diet-induced obesity and metabolic dysfunction. Accordingly, we examined the effects of TSP-1 gene disruption on weight gain, adiposity, and adipose tissue inflammation in mice receiving a high-fat diet (HFD: 60% fat, 20% carbohydrate) or a high-carbohydrate low-fat diet (HCLFD: 10% fat, 70% carbohydrate). HFD mice had significantly higher TSP-1 expression in perigonadal adipose tissue; TSP-1 was predominantly localized in the adipose interstitium. TSP-1 loss attenuated weight gain and fat accumulation in HFD and HCLFD groups. Compared with corresponding wild-type animals, TSP-1-null mice had decreased insulin levels but exhibited elevated free fatty acid and triglyceride levels, suggesting impaired fatty acid uptake. TSP-1 loss did not affect adipocyte size and had no effect on adipose vascular density. However, TSP-1-null mice exhibited attenuated tumor necrosis factor-α mRNA expression and reduced macrophage infiltration, suggesting a role for TSP-1 in mediating obesity-associated inflammation. In vitro, TSP-1 enhanced proliferation of 3T3-L1 preadipocytes but did not modulate inflammatory cytokine and chemokine synthesis. In conclusion, TSP-1 upregulation contributes to weight gain, adipose growth, and the pathogenesis of metabolic dysfunction. The effects of TSP-1 may involve stimulation of adipocyte proliferation, activation of inflammatory signaling, and facilitated fatty acid uptake by adipocytes.

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