scholarly journals PPARs-Orchestrated Metabolic Homeostasis in the Adipose Tissue

2021 ◽  
Vol 22 (16) ◽  
pp. 8974
Author(s):  
Chen Sun ◽  
Shuyu Mao ◽  
Siyu Chen ◽  
Wenxiang Zhang ◽  
Chang Liu

It has been more than three decades since peroxisome proliferator-activated receptors (PPARs) were first discovered. Many investigations have revealed the central regulators of PPARs in lipid and glucose homeostasis in response to different nutrient conditions. PPARs have attracted much attention due to their ability to improve metabolic syndromes, and they have also been proposed as classical drug targets for the treatment of hyperlipidemia and type 2 diabetes (T2D) mellitus. In parallel, adipose tissue is known to play a unique role in the pathogenesis of insulin resistance and metabolic syndromes due to its ability to “safely” store lipids and secrete cytokines that regulate whole-body metabolism. Adipose tissue relies on a complex and subtle network of transcription factors to maintain its normal physiological function, by coordinating various molecular events, among which PPARs play distinctive and indispensable roles in adipocyte differentiation, lipid metabolism, adipokine secretion, and insulin sensitivity. In this review, we discuss the characteristics of PPARs with special emphasis on the roles of the different isotypes in adipocyte biology.

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 629
Author(s):  
Jorge Gutiérrez-Cuevas ◽  
Ana Sandoval-Rodriguez ◽  
Alejandra Meza-Rios ◽  
Hugo Christian Monroy-Ramírez ◽  
Marina Galicia-Moreno ◽  
...  

Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.


GeroScience ◽  
2021 ◽  
Author(s):  
Haihui Zhuang ◽  
Sira Karvinen ◽  
Timo Törmäkangas ◽  
Xiaobo Zhang ◽  
Xiaowei Ojanen ◽  
...  

AbstractAerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging, and their interaction on metabolism, we utilized rat models selectively bred for low and high intrinsic aerobic capacity (LCRs/HCRs) and compared the metabolomics of serum, muscle, and white adipose tissue (WAT) at two time points: Young rats were sacrificed at 9 months of age, and old rats were sacrificed at 21 months of age. Targeted and semi-quantitative metabolomics analysis was performed on the ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS) platform. The effects of aerobic capacity, aging, and their interaction were studied via regression analysis. Our results showed that high aerobic capacity is associated with an accumulation of isovalerylcarnitine in muscle and serum at rest, which is likely due to more efficient leucine catabolism in muscle. With aging, several amino acids were downregulated in muscle, indicating more efficient amino acid metabolism, whereas in WAT less efficient amino acid metabolism and decreased mitochondrial β-oxidation were observed. Our results further revealed that high aerobic capacity and aging interactively affect lipid metabolism in muscle and WAT, possibly combating unfavorable aging-related changes in whole body metabolism. Our results highlight the significant role of WAT metabolism for healthy aging.


2006 ◽  
Vol 290 (6) ◽  
pp. E1227-E1236 ◽  
Author(s):  
Hyunsook Kim ◽  
Patricia A. Pennisi ◽  
Oksana Gavrilova ◽  
Stephanie Pack ◽  
William Jou ◽  
...  

The antiobesity and antidiabetic effects of the β3-adrenergic agonists were investigated on nonobese type 2 diabetic MKR mice after injection with a β3-adrenergic agonist, CL-316243. An intact response to acute CL-316243 treatment was observed in MKR mice. Chronic intraperitoneal CL-316243 treatment of MKR mice reduced blood glucose and serum insulin levels. Hyperinsulinemic euglycemic clamps exhibited improvement of the whole body insulin sensitivity and glucose homeostasis concurrently with enhanced insulin action in liver and adipose tissue. Treating MKR mice with CL-316243 significantly lowered serum and hepatic lipid levels, in part due to increased whole body triglyceride clearance and fatty acid oxidation in adipocytes. A significant reduction in total body fat content and epididymal fat weight was observed along with enhanced metabolic rate in both wild-type and MKR mice after treatment. These data demonstrate that β3-adrenergic activation improves the diabetic state of nonobese diabetic MKR mice by potentiation of free fatty acid oxidation by adipose tissue, suggesting a potential therapeutic role for β3-adrenergic agonists in nonobese diabetic subjects.


2006 ◽  
Vol 92 (2) ◽  
pp. 386-395 ◽  
Author(s):  
Arya M. Sharma ◽  
Bart Staels

Abstract Context: Adipose tissue is a metabolically dynamic organ, serving as a buffer to control fatty acid flux and a regulator of endocrine function. In obese subjects, and those with type 2 diabetes or the metabolic syndrome, adipose tissue function is altered (i.e. adipocytes display morphological differences alongside aberrant endocrine and metabolic function and low-grade inflammation). Evidence Acquisition: Articles on the role of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissue of healthy individuals and those with obesity, metabolic syndrome, or type 2 diabetes were sourced using MEDLINE (1990–2006). Evidence Synthesis: Articles were assessed to provide a comprehensive overview of how PPARγ-activating ligands improve adipose tissue function, and how this links to improvements in insulin resistance and the progression to type 2 diabetes and atherosclerosis. Conclusions: PPARγ is highly expressed in adipose tissue, where its activation with thiazolidinediones alters fat topography and adipocyte phenotype and up-regulates genes involved in fatty acid metabolism and triglyceride storage. Furthermore, PPARγ activation is associated with potentially beneficial effects on the expression and secretion of a range of factors, including adiponectin, resistin, IL-6, TNFα, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, and angiotensinogen, as well as a reduction in plasma nonesterified fatty acid supply. The effects of PPARγ also extend to macrophages, where they suppress production of inflammatory mediators. As such, PPARγ activation appears to have a beneficial effect on the relationship between the macrophage and adipocyte that is distorted in obesity. Thus, PPARγ-activating ligands improve adipose tissue function and may have a role in preventing progression of insulin resistance to diabetes and endothelial dysfunction to atherosclerosis.


Author(s):  
Ann Louise Olson

AbstractSkeletal muscle and adipose tissue play a major role in the regulation of whole-body glucose homeostasis. Much of the coordinated regulation of whole-body glucose homeostasis results from the regulation of lipid storage and release by adipose tissue and efficient switching between glucose oxidation and fatty acid oxidation in skeletal muscle. A control point for these biochemical actions center around the regulation of the insulin responsive glucose transporter, GLUT4. This review examines the regulation of GLUT4 in adipose tissue and skeletal muscle, in the context of the steroid nuclear hormone receptor signaling.


PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Pieter de Lange ◽  
Assunta Lombardi ◽  
Elena Silvestri ◽  
Fernando Goglia ◽  
Antonia Lanni ◽  
...  

The peroxisome proliferator-activated receptors (PPARs), which are ligand-inducible transcription factors expressed in a variety of tissues, have been shown to perform key roles in lipid homeostasis. In physiological situations such as fasting and physical exercise, one PPAR subtype, PPARδ, triggers a transcriptional program in skeletal muscle leading to a switch in fuel usage from glucose/fatty acids to solely fatty acids, thereby drastically increasing its oxidative capacity. The metabolic action of PPARδ has also been verified in humans. In addition, it has become clear that the action of PPARδ is not restricted to skeletal muscle. Indeed, PPARδ has been shown to play a crucial role in whole-body lipid homeostasis as well as in insulin sensitivity, and it is active not only in skeletal muscle (as an activator of fat burning) but also in the liver (where it can activate glycolysis/lipogenesis, with the produced fat being oxidized in muscle) and in the adipose tissue (by incrementing lipolysis). The main aim of this review is to highlight the central role for activated PPARδ in the reversal of any tendency toward the development of insulin resistance.


1993 ◽  
Vol 264 (5) ◽  
pp. R1017-R1023 ◽  
Author(s):  
G. Kortner ◽  
K. Schildhauer ◽  
O. Petrova ◽  
I. Schmidt

To determine developmental changes of brown adipose tissue (BAT) thermogenic activity at defined circadian and thermal states, we evaluated the time course of cold-induced increases of in vitro guanosine 5'-diphosphate (GDP) binding in parallel with whole body metabolism (oxygen consumption, VO2) and core temperature (Tc) in 1- to 11-day-old rat pups. During the maximum phase of the juvenile diurnal cycle, Tc of littermates was recorded continuously and VO2 alternately until 2 min before animals were killed for removal of interscapular BAT. GDP binding after 1.5 h at thermoneutrality and its increase during physiologically comparable cold loads were significantly lower in 1-day-old pups than in 5- and 11-day-old pups. Cold defense was activated more rapidly in the older pups, but GDP binding in even the 1-day-old pups was significantly increased during the second 10-min period of cold exposure. We conclude that rapid changes in thermogenic activity, in connection with the known developmental changes in the dependence of the suckling rat's metabolic cold defense on maternal and sibling contact and circadian phase, will distort longitudinal studies of any fast-changing BAT parameter when the conditions immediately before tissue removal are not thoroughly controlled.


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