scholarly journals Improved Insulin Resistance and Lipid Metabolism by Cinnamon Extract through Activation of Peroxisome Proliferator-Activated Receptors

PPAR Research ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaoyan Sheng ◽  
Yuebo Zhang ◽  
Zhenwei Gong ◽  
Cheng Huang ◽  
Ying Qin Zang

Peroxisome proliferator-activated receptors (PPARs) are transcriptional factors involved in the regulation of insulin resistance and adipogenesis. Cinnamon, a widely used spice in food preparation and traditional antidiabetic remedy, is found to activate PPARγandα, resulting in improved insulin resistance, reduced fasted glucose, FFA, LDL-c, and AST levels in high-caloric diet-induced obesity (DIO) anddb/dbmice in its water extract form. In vitro studies demonstrate that cinnamon increases the expression of peroxisome proliferator-activated receptorsγandα(PPARγ/α) and their target genes such as LPL, CD36, GLUT4, and ACO in 3T3-L1 adipocyte. The transactivities of both full length and ligand-binding domain (LBD) of PPARγand PPARαare activated by cinnamon as evidenced by reporter gene assays. These data suggest that cinnamon in its water extract form can act as a dual activator of PPARγandα, and may be an alternative to PPARγactivator in managing obesity-related diabetes and hyperlipidemia.

2005 ◽  
Vol 288 (3) ◽  
pp. H1037-H1043 ◽  
Author(s):  
Ernesto L. Schiffrin

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that heterodimerize with the retinoid X receptor and then modulate the function of many target genes. Three PPARs are known: α, β/δ, and γ. The better known are PPAR-α and PPAR-γ, which may be activated by different synthetic agonists, although the endogenous ligands are unknown. PPAR-α is involved in fatty acid oxidation and expressed in the liver, kidney, and skeletal muscle, whereas PPAR-γ is involved in fat cell differentiation, lipid storage, and insulin sensitivity. However, both have been shown to be present in variable amounts in cardiovascular tissues, including endothelium, smooth muscle cells, macrophages, and the heart. The activators of PPAR-α (fibrates) and PPAR-γ (thiazolidinediones or glitazones) antagonized the actions of angiotensin II in vivo and in vitro and exerted cardiovascular antioxidant and anti-inflammatory effects. PPAR activators lowered blood pressure, induced favorable effects on the heart, and corrected vascular structure and endothelial dysfunction in several rodent models of hypertension. Activators of PPARs may become therapeutic agents useful in the prevention of cardiovascular disease beyond their effects on carbohydrate and lipid metabolism. Some side effects, such as weight gain, as well as documented aggravation of advanced heart failure through fluid retention by glitazones, may, however, limit their therapeutic application in prevention of cardiovascular disease.


2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Fazliana Mansor ◽  
Harvest F. Gu ◽  
Claes-Göran Östenson ◽  
Louise Mannerås-Holm ◽  
Elisabet Stener-Victorin ◽  
...  

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor that regulates lipid and glucose metabolism. We investigated the effects ofLabisia pumila(LP) standardized water extract on PPARgamma transcriptional activity in adipocytesin vitroandin vivo. We used a rat model of dihydrotestosterone- (DHT-) induced polycystic ovary syndrome (PCOS), a condition characterized by insulin resistance. At 9 weeks of age, the PCOS rats were randomly subdivided into two groups: PCOS-LP (50 mg/kg/day of LP) and PCOS-control (1 mL of deionised water) for 4-5 weeks on the same schedule. Real-time RT-PCR was performed to determine the PPARgamma mRNA levels. LP upregulated PPARgamma mRNA level by 40% in the PCOS rats. Western blot analysis further demonstrated the increased PPARgamma protein levels in parallel with upregulation in mRNA. These observations were further proven by adipocytes culture. Differentiated 3T3-L1 adipocytes were treated with final concentration of 100 μg/mL LP and compared to untreated control and 10 μM of rosiglitazone (in type of thiazolidinediones). LP increased PPARgamma expressions at both mRNA and protein levels and enhanced the effect of glucose uptake in the insulin-resistant cells. The data suggest that LP may ameliorate insulin resistance in adipocytes via the upregulation of PPARgamma pathway.


PPAR Research ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Li Fang ◽  
Man Zhang ◽  
Yanhui Li ◽  
Yan Liu ◽  
Qinghua Cui ◽  
...  

The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors of the nuclear receptor superfamily. Upon ligand binding, PPARs activate target gene transcription and regulate a variety of important physiological processes such as lipid metabolism, inflammation, and wound healing. Here, we describe the first database of PPAR target genes, PPARgene. Among the 225 experimentally verified PPAR target genes, 83 are for PPARα, 83 are for PPARβ/δ, and 104 are for PPARγ. Detailed information including tissue types, species, and reference PubMed IDs was also provided. In addition, we developed a machine learning method to predict novel PPAR target genes by integratingin silicoPPAR-responsive element (PPRE) analysis with high throughput gene expression data. Fivefold cross validation showed that the performance of this prediction method was significantly improved compared to thein silicoPPRE analysis method. The prediction tool is also implemented in the PPARgene database.


PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e64258 ◽  
Author(s):  
D'Angelo Carlo Magliano ◽  
Thereza Cristina Lonzetti Bargut ◽  
Simone Nunes de Carvalho ◽  
Marcia Barbosa Aguila ◽  
Carlos Alberto Mandarim-de-Lacerda ◽  
...  

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A45-A46
Author(s):  
Evangelia Evelyn Tsakiridis ◽  
Marisa Morrow ◽  
Andrea Llanos ◽  
Bo Wang ◽  
Alison Holloway ◽  
...  

Abstract Deltamethrin is a commonly used pesticide for the control of mosquito populations. Despite widespread use, the effects of deltamethrin on adiposity and glucose homeostasis have been equivocal with some studies showing increased, decreased and no effect on adiposity and glycemic control. However, no study to date has investigated the effect of deltamethrin in mice housed at thermoneutral temperatures, which is important for modelling metabolic diseases in rodents due to reduced thermal stress and constitutive activation of brown adipose tissue. In the current study we demonstrate for the first time that deltamethrin reduces uncoupling protein-1 expression in brown adipocytes cultured in vitro at concentrations as low as 1pm. Meanwhile, in-vivo deltamethrin does not appear to alter glycemic control or promote adiposity at exposures equivalent to 0.01, 0.1 or 1.0 mg/kg/day. Together, our study demonstrates environmentally relevant exposure to deltamethrin does not exacerbate diet induced obesity or insulin resistance.


2014 ◽  
Vol 53 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Xiaoting Jiang ◽  
Xin Ye ◽  
Wei Guo ◽  
Hongyun Lu ◽  
Zhanguo Gao

Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor whose activation is dependent on a ligand. PPARγ activation by exogenous ligands, such as thiazolidinediones (TZDs), is a strategy in the treatment of type 2 diabetes mellitus for the improvement of insulin sensitivity. In addition to a ligand, PPARγ function is also regulated by posttranslational modifications, such as phosphorylation, sumoylation, and ubiquitination. Herein, we report that the PPARγ protein is modified by acetylation, which induces the PPARγ function in the absence of an external ligand. We observed that histone deacetylase 3 (HDAC3) interacted with PPARγ to deacetylate the protein. In immunoprecipitation assays, the HDAC3 protein was associated with the PPARγ protein. Inhibition of HDAC3 using RNAi-mediated knockdown or HDAC3 inhibitor increased acetylation of the PPARγ protein. Furthermore, inhibition of HDAC3 enhanced the expression of PPARγ target genes such as adiponectin and aP2. The expression was associated with an increase in glucose uptake and insulin signaling in adipocytes. HDAC3 inhibition enhanced lipid accumulation during differentiation of adipocytes. PPARγ acetylation was also induced by pioglitazone and acetylation was required for PPARγ activation. In the absence of TZDs, the acetylation from HDAC3 inhibition was sufficient to induce the transcriptional activity of PPARγ. Treating diet-induced obesity mice with HDAC3 inhibitor or pioglitazone for 2 weeks significantly improved high-fat-diet-induced insulin resistance. Our results indicate that acetylation of PPARγ is a ligand-independent mechanism of PPARγ activation. HDAC3 inhibitor is a potential PPARγ activator for the improvement of insulin sensitivity.


PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Angela Tesse ◽  
Ramaroson Andriantsitohaina ◽  
Thierry Ragot

Activation of peroxisome proliferator-activated receptors (PPARs), and particularly of PPARαand PPARγ, using selective agonists, is currently used in the treatment of metabolic diseases such as hypertriglyceridemia and type 2 diabetes mellitus. PPARαand PPARγanti-inflammatory, antiproliferative and antiangiogenic properties in cardiovascular cells were extensively clarified in a variety of in vitro and in vivo models. In contrast, the role of PPARδin cardiovascular system is poorly understood. Prostacyclin, the predominant prostanoid released by vascular cells, is a putative endogenous agonist for PPARδ, but only recently PPARδselective synthetic agonists were found, improving studies about the physiological and pathophysiological roles of PPARδactivation. Recent reports suggest that the PPARδactivation may play a pivotal role to regulate inflammation, apoptosis, and cell proliferation, suggesting that this transcriptional factor could become an interesting pharmacological target to regulate cardiovascular cell apoptosis, proliferation, inflammation, and metabolism.


2006 ◽  
Vol 26 (15) ◽  
pp. 5698-5714 ◽  
Author(s):  
Ronni Nielsen ◽  
Lars Grøntved ◽  
Hendrik G. Stunnenberg ◽  
Susanne Mandrup

ABSTRACT Investigations of the molecular events involved in activation of genomic target genes by peroxisome proliferator-activated receptors (PPARs) have been hampered by the inability to establish a clean on/off state of the receptor in living cells. Here we show that the combination of adenoviral delivery and chromatin immunoprecipitation (ChIP) is ideal for dissecting these mechanisms. Adenoviral delivery of PPARs leads to a rapid and synchronous expression of the PPAR subtypes, establishment of transcriptional active complexes at genomic loci, and immediate activation of even silent target genes. We demonstrate that PPARγ2 possesses considerable ligand-dependent as well as independent transactivation potential and that agonists increase the occupancy of PPARγ2/retinoid X receptor at PPAR response elements. Intriguingly, by direct comparison of the PPARs (α, γ, and β/δ), we show that the subtypes have very different abilities to gain access to target sites and that in general the genomic occupancy correlates with the ability to activate the corresponding target gene. In addition, the specificity and potency of activation by PPAR subtypes are highly dependent on the cell type. Thus, PPAR subtype-specific activation of genomic target genes involves an intricate interplay between the properties of the subtype- and cell-type-specific settings at the individual target loci.


PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Sean R. Pyper ◽  
Navin Viswakarma ◽  
Yuzhi Jia ◽  
Yi-Jun Zhu ◽  
Joseph D. Fondell ◽  
...  

The peroxisome proliferator-activated receptor- (PPAR) plays a key role in lipid metabolism and energy combustion. Chronic activation of PPAR in rodents leads to the development of hepatocellular carcinomas. The ability of PPAR to induce expression of its target genes depends on Mediator, an evolutionarily conserved complex of cofactors and, in particular, the subunit 1 (Med1) of this complex. Here, we report the identification and characterization of PPAR-interacting cofactor (PRIC)-295 (PRIC295), a novel coactivator protein, and show that it interacts with the Med1 and Med24 subunits of the Mediator complex. PRIC295 contains 10 LXXLL signature motifs that facilitate nuclear receptor binding and interacts with PPAR and five other members of the nuclear receptor superfamily in a ligand-dependent manner. PRIC295 enhances the transactivation function of PPAR, PPAR, and ER. These data demonstrate that PRIC295 interacts with nuclear receptors such as PPAR and functions as a transcription coactivator underin vitroconditions and may play an important role in mediating the effectsin vivoas a member of the PRIC complex with Med1 and Med24.


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