scholarly journals Remodeling of White Adipose Tissue after Retinoic Acid Administration in Mice

Endocrinology ◽  
2006 ◽  
Vol 147 (11) ◽  
pp. 5325-5332 ◽  
Author(s):  
Josep Mercader ◽  
Joan Ribot ◽  
Incoronata Murano ◽  
Francisco Felipe ◽  
Saverio Cinti ◽  
...  

A reduced brown adipose phenotype in white adipose tissue (WAT) may contribute to obesity and type 2 diabetes in humans. Retinoic acid, the carboxylic form of vitamin A, triggers in rodents a reduction of body weight and adiposity and an increased expression of uncoupling proteins in brown adipose tissue and skeletal muscle. In this study, we investigated possible remodeling effects of all-trans retinoic acid (ATRA) in WAT depots. Changes in the expression of genes related to thermogenesis and fatty acid oxidation and levels of phosphorylated retinoblastoma protein were analyzed in WAT depots of adult NMRI male mice acutely injected with ATRA or vehicle, together with biometric and blood parameters. Body fat loss after ATRA treatment was unaccompanied by any increase in circulating nonesterified fatty acids or ketone bodies and accompanied by increased rectal temperature. The treatment triggered an up-regulation of the mRNA levels of uncoupling proteins 1 and 2, peroxisome proliferator-activated receptor γ coactivator-1α, peroxisome proliferator-activated receptor α, muscle- and liver-type carnitine palmitoyltransferase 1, and subunit II of cytochrome oxidase in different WAT depots. Levels of phosphorylated retinoblastoma protein in WAT depots were increased after ATRA treatment. Adipocyte size was reduced, and the number of multilocular adipocytes was increased in inguinal WAT of ATRA-treated mice. The results indicate that ATRA favors the acquisition of brown adipose tissue-like properties in WAT. Understanding the mechanisms and effectors involved in the remodeling of WAT can contribute to new avenues of prevention and treatment of obesity and type 2 diabetes.

2021 ◽  
pp. 1-31
Author(s):  
Long Cheng ◽  
Jingkang Wang ◽  
Yongcheng An ◽  
Hongyu Dai ◽  
Yuhui Duan ◽  
...  

Abstract The current epidemic of type 2 diabetes mellitus (T2DM) significantly affects human health worldwide. Activation of brown adipocytes and browning of white adipocytes are considered as a promising molecular target for T2DM treatment. Mulberry leaf, a traditional Chinese medicine, has been demonstrated to have multi-biological activities, including anti-diabetic and anti-inflammatory effects. Our experiment results showed that mulberry leaf significantly alleviated the disorder of glucose and lipid metabolism in T2DM rats including reducing body weight (BW) gain, Lee’s index, food intake, inguinal white adipose tissue (IWAT) accumulation, blood lipid fasting insulin level and fasting blood glucose level, increasing the ratios of brown adipose tissue (BAT) mass to BW, and improving insulin sensitivity and liver function. In addition, mulberry leaf induced browning of IWAT by enhancing the expressions of brown-mark genes as well as beige-specific genes, including uncoupling protein-1 (UCP1), peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), peroxisome proliferator-activated receptor alpha (PPARα), PRD1-BF-1-RIZ1 homologous domain containing protein 16 (PRDM16), cell death inducing DFFA like effector A (Cidea), CD137 and transmembrane protein 26 (TMEM26). Mulberry leaf also activated BAT by increasing the expressions of brown-mark genes including UCP1, PGC-1α, PPARα, PRDM16 and Cidea. Moreover, mulberry leaf enhanced the expression of nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) genes that are responsible for mitochondrial biogenesis in IWAT and BAT. Importantly, mulberry leaf also increased the expression of UCP1 and carnitine palmitoyl transferase 1 (CPT1) protein in both IWAT and BAT via a mechanism involving Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and PGC-1α pathway. In conclusion, our findings identify the role of mulberry leaf in inducing adipose browning, indicating that mulberry leaf may be used as a candidate browning agent for the treatment of T2DM.


Endocrinology ◽  
2001 ◽  
Vol 142 (3) ◽  
pp. 1269-1277 ◽  
Author(s):  
James M. Way ◽  
W. Wallace Harrington ◽  
Kathleen K. Brown ◽  
William K. Gottschalk ◽  
Scott S. Sundseth ◽  
...  

Abstract Peroxisome proliferator-activated receptor γ (PPARγ) agonists, including the glitazone class of drugs, are insulin sensitizers that reduce glucose and lipid levels in patients with type 2 diabetes mellitus. To more fully understand the molecular mechanisms underlying their therapeutic actions, we have characterized the effects of the potent, tyrosine-based PPARγ ligand GW1929 on serum glucose and lipid parameters and gene expression in Zucker diabetic fatty rats. In time-course studies, GW1929 treatment decreased circulating FFA levels before reducing glucose and triglyceride levels. We used a comprehensive and unbiased messenger RNA profiling technique to identify genes regulated either directly or indirectly by PPARγ in epididymal white adipose tissue, interscapular brown adipose tissue, liver, and soleus skeletal muscle. PPARγ activation stimulated the expression of a large number of genes involved in lipogenesis and fatty acid metabolism in both white adipose tissue and brown adipose tissue. In muscle, PPARγ agonist treatment decreased the expression of pyruvate dehydrogenase kinase 4, which represses oxidative glucose metabolism, and also decreased the expression of genes involved in fatty acid transport and oxidation. These changes suggest a molecular basis for PPARγ-mediated increases in glucose utilization in muscle. In liver, PPARγ activation coordinately decreased the expression of genes involved in gluconeogenesis. We conclude from these studies that the antidiabetic actions of PPARγ agonists are probably the consequence of 1) their effects on FFA levels, and 2), their coordinate effects on gene expression in multiple insulin-sensitive tissues.


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.


2020 ◽  
Vol 12 (2) ◽  
pp. 85-101
Author(s):  
Anna Meiliana ◽  
Nurrani Mustika Dewi ◽  
Andi Wijaya

BACKGROUND: Obesity has been decades become a highly interest study, accompanied by the realization that adipose tissue (AT) plays a major role in the regulation of metabolic function.CONTENT: In past few years, adipocytes classification, development, and differentiation has been significant changes. The white adipose tissue (WAT) can transform to a phenotype like brown adipose (BAT) type and function. Exercise and cold induction were the most common factor for fat browning; however batokines such as fibroblast growth factor (FGF)-21, interleukin (IL)-6, Slit homolog 2 protein (SLIT2)-C, and Meteorin-like protein (METRNL) perform a beneficial browning action by increasing peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α protein levels, a key factor to stimulate mitochondrial biogenesis and uncoupling Protein 1 (UCP1) transcription, thus change the WAT phenotype into beige.SUMMARY: AT recently known as a complex organ, not only bearing a storage function but as well as the master regulator of energy balance and nutritional homeostasis; brown and beige fat express constitutively high levels of thermogenic genes and raise our expectation on new strategies for fighting obesity and metabolic disorders.KEYWORDS: obesity, white adipose tissue, brown adipose tissue, beige adipose tissue, inflammation, IR, metabolic disease


Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1482
Author(s):  
Ahmad Agil ◽  
Miguel Navarro-Alarcon ◽  
Fatma Abo Zakaib Ali ◽  
Ashraf Albrakati ◽  
Diego Salagre ◽  
...  

Developing novel drugs/targets remains a major effort toward controlling obesity-related type 2 diabetes (diabesity). Melatonin controls obesity and improves glucose homeostasis in rodents, mainly via the thermogenic effects of increasing the amount of brown adipose tissue (BAT) and increases in mitochondrial mass, amount of UCP1 protein, and thermogenic capacity. Importantly, mitochondria are widely known as a therapeutic target of melatonin; however, direct evidence of melatonin on the function of mitochondria from BAT and the mechanistic pathways underlying these effects remains lacking. This study investigated the effects of melatonin on mitochondrial functions in BAT of Zücker diabetic fatty (ZDF) rats, which are considered a model of obesity-related type 2 diabetes mellitus (T2DM). At five weeks of age, Zücker lean (ZL) and ZDF rats were subdivided into two groups, consisting of control and treated with oral melatonin for six weeks. Mitochondria were isolated from BAT of animals from both groups, using subcellular fractionation techniques, followed by measurement of several mitochondrial parameters, including respiratory control ratio (RCR), phosphorylation coefficient (ADP/O ratio), ATP production, level of mitochondrial nitrites, superoxide dismutase activity, and alteration in the mitochondrial permeability transition pore (mPTP). Interestingly, melatonin increased RCR in mitochondria from brown fat of both ZL and ZDF rats through the reduction of the proton leak component of respiration (state 4). In addition, melatonin improved the ADP/O ratio in obese rats and augmented ATP production in lean rats. Further, melatonin reduced mitochondrial nitrosative and oxidative status by decreasing nitrite levels and increasing superoxide dismutase activity in both groups, as well as inhibited mPTP in mitochondria isolated from brown fat. Taken together, the present data revealed that chronic oral administration of melatonin improved mitochondrial respiration in brown adipocytes, while decreasing oxidative and nitrosative stress and susceptibility of adipocytes to apoptosis in ZDF rats, suggesting a beneficial use in the treatment of diabesity. Further research regarding the molecular mechanisms underlying the effects of melatonin on diabesity is warranted.


Author(s):  
Ivo Romauld Sagayaraj ◽  
Akilashree S ◽  
Brindha Devi P

Objective: Obesity is the major problem which may lead to many other health ailments such as atherosclerosis, stroke, and depression. Both the cause as well as the treatment lies in the adipose tissue. The two main adipocytes, white adipose tissue (WAT) and brown adipose tissue (BAT) are responsible for the accumulation of fat and transformation of fat into heat, respectively. This review discusses the induction of BAT and browning of WAT by different pathways and activators to decrease the rate of obesity. Methods: Understanding the regulators, activators and secreted proteins which induce browning of WAT to BAT, as the BAT engage in thermogenesis process and transform fat into heat rather than storing it (WAT). Some of the core regulators are peroxisome proliferator-activated receptor-γ, PRDM16, PGC-1α. Results: A basic study explained about the origin of BAT and its functions, the function of hormones in BAT growth and its regulations. These studies provided the platform to understand about the mechanism of regulators, activators and secreted proteins which help in treating obesity and its related disorders by inducing the amount of BAT. Conclusion: The major health ailments caused by obesity can be reduced by increasing the activity of BAT and transforming WAT into BAT. A challenging way to treat these ailments is by regulating the activators and hormones responsible for the induction of BAT, so it transforms the excess fat into heat and avoiding the accumulation of fat. By understanding the role of regulators in the adipose tissue can provide various methods to reduce the chance of obesity and enhance efficient treatment in both children and adults.


Author(s):  
Jennifer Honek ◽  
Sharon Lim ◽  
Carina Fischer ◽  
Hideki Iwamoto ◽  
Takahiro Seki ◽  
...  

AbstractThe number of obese and overweight individuals is globally rising, and obesity-associated disorders such as type 2 diabetes, cardiovascular disease and certain types of cancer are among the most common causes of death. While white adipose tissue is the key player in the storage of energy, active brown adipose tissue expends energy due to its thermogenic capacity. Expanding and activating brown adipose tissue using pharmacological approaches therefore might offer an attractive possibility for therapeutic intervention to counteract obesity and its consequences for metabolic health.


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