Effects of chronic AICAR treatment on fiber composition, enzyme activity, UCP3, and PGC-1 in rat muscles

2003 ◽  
Vol 95 (3) ◽  
pp. 960-968 ◽  
Author(s):  
Masataka Suwa ◽  
Hiroshi Nakano ◽  
Shuzo Kumagai

This study was designed to determine the histological and metabolic effects of the administration of 5′-AMP-activated protein kinase (AMPK) activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) for 14 successive days. AICAR treatment caused a significant decrease in the percentage of type IIB fibers and the concomitant increase in the percentage of type IIX fibers in extensor digitorum longus (EDL) muscle. The capillary density and the capillary-to-fiber ratio were not altered by AICAR. AICAR treatment increased the glycolytic and oxidative enzyme activities but not the antioxidant enzyme activities. The AICAR treatment increased the uncoupling protein 3 (UCP3) level in EDL and the peroxisome proliferator-activated receptor-γ coactivator-1α protein level in the soleus and EDL muscles, whereas the myogenin level was not altered by AICAR. These results seem to imply that the chronic activation of AMPK alters such muscle histochemical and metabolic characteristics.

Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1988 ◽  
Author(s):  
Park ◽  
Kim ◽  
Jung ◽  
Ahn ◽  
Kwak ◽  
...  

Obesity is a global health threat. Herein, we evaluated the underlying mechanism of anti-obese features of bitter orange (Citrus aurantium Linné, CA). Eight-week-administration of CA in high fat diet-induced obese C57BL/6 mice resulted in a significant decrease of body weight, adipose tissue weight and serum cholesterol. In further in vitro studies, we observed decreased lipid droplets in CA-treated 3T3-L1 adipocytes. Suppressed peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha indicated CA-inhibited adipogenesis. Moreover, CA-treated primary cultured brown adipocytes displayed increased differentiation associated with elevation of thermogenic factors including uncoupling protein 1 and PPARγ coactivator 1 alpha as well. The effects of CA in both adipocytes were abolished in AMP-activated protein kinase alpha (AMPKα)-suppressed environments, suggesting the anti-adipogenic and pro-thermogenic actions of CA were dependent on AMPKα pathway. In conclusion, our results suggest CA as a potential anti-obese agent which regulates adipogenesis and thermogenesis via AMPKα.


2020 ◽  
Author(s):  
David Aguilar-Recarte ◽  
Emma Barroso ◽  
Javier Pizarro-Delgado ◽  
Lucía Peña ◽  
Maria Ruart ◽  
...  

Abstract Peroxisome proliferator-activated receptor β/δ(PPARβ/δ) activates AMP-activated protein kinase (AMPK) and plays a crucial role in glucose and lipid metabolism. Here, we examined whether the beneficial effects of PPARβ/δ activation depended on growth differentiation factor 15 (GDF15), a stress response cytokine that regulates energy metabolism. Pharmacological PPARβ/δ activation increased GDF15 levels and ameliorated glucose intolerance, fatty acid oxidation, endoplasmic reticulum stress, inflammation and activated AMPK in HFD-fed mice, whereas these effects were abrogated by the injection of a GDF15 neutralizing antibody and in Gdf15-/- mice. The AMPK-p53 pathway was involved in the PPARβ/δ-mediated increase in GDF15, which in turn activated again AMPK. Finally, Gdf15-/- mice showed reduced AMPK activation in skeletal muscle, whereas GDF15 administration resulted in AMPK activation in this organ. Collectively, these data reveal a novel mechanism by which PPARβ/δ activation increases the levels of GDF15 via AMPK and p53, which in turn mediates the metabolic effects of PPARβ/δ by sustaining AMPK activation.


2007 ◽  
Vol 27 (12) ◽  
pp. 4317-4327 ◽  
Author(s):  
Atsushi Suzuki ◽  
Shiki Okamoto ◽  
Suni Lee ◽  
Kumiko Saito ◽  
Tetsuya Shiuchi ◽  
...  

ABSTRACT Leptin stimulates fatty acid oxidation in skeletal muscle through the activation of AMP-activated protein kinase (AMPK) and the induction of gene expression, such as that for peroxisome proliferator-activated receptor α (PPARα). We now show that leptin stimulates fatty acid oxidation and PPARα gene expression in the C2C12 muscle cell line through the activation of AMPK containing the α2 subunit (α2AMPK) and through changes in the subcellular localization of this enzyme. Activated α2AMPK containing the β1 subunit was shown to be retained in the cytoplasm, where it phosphorylated acetyl coenzyme A carboxylase and thereby stimulated fatty acid oxidation. In contrast, α2AMPK containing the β2 subunit transiently increased fatty acid oxidation but underwent rapid translocation to the nucleus, where it induced PPARα gene transcription. A nuclear localization signal and Thr172 phosphorylation of α2 were found to be essential for nuclear translocation of α2AMPK, whereas the myristoylation of β1 anchors α2AMPK in the cytoplasm. The prevention of α2AMPK activation and the change in its subcellular localization inhibited the metabolic effects of leptin. Our data thus suggest that the activation of and changes in the subcellular localization of α2AMPK are required for leptin-induced stimulation of fatty acid oxidation and PPARα gene expression in muscle cells.


Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 185
Author(s):  
Clara Depommier ◽  
Rosa Maria Vitale ◽  
Fabio Arturo Iannotti ◽  
Cristoforo Silvestri ◽  
Nicolas Flamand ◽  
...  

Akkermansia muciniphila is considered as one of the next-generation beneficial bacteria in the context of obesity and associated metabolic disorders. Although a first proof-of-concept of its beneficial effects has been established in the context of metabolic syndrome in humans, mechanisms are not yet fully understood. This study aimed at deciphering whether the bacterium exerts its beneficial properties through the modulation of the endocannabinoidome (eCBome). Circulating levels of 25 endogenous endocannabinoid-related lipids were quantified by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in the plasma of overweight or obese individuals before and after a 3 months intervention consisting of the daily ingestion of either alive or pasteurized A. muciniphila. Results from multivariate analyses suggested that the beneficial effects of A. muciniphila were not linked to an overall modification of the eCBome. However, subsequent univariate analysis showed that the decrease in 1-Palmitoyl-glycerol (1-PG) and 2-Palmitoyl-glycerol (2-PG), two eCBome lipids, observed in the placebo group was significantly counteracted by the alive bacterium, and to a lower extent by the pasteurized form. We also discovered that 1- and 2-PG are endogenous activators of peroxisome proliferator-activated receptor alpha (PPARα). We hypothesize that PPARα activation by mono-palmitoyl-glycerols may underlie part of the beneficial metabolic effects induced by A. muciniphila in human metabolic syndrome.


Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1025
Author(s):  
Ahmed Alalaiwe ◽  
Jia-You Fang ◽  
Hsien-Ju Lee ◽  
Chun-Hui Chiu ◽  
Ching-Yun Hsu

Curcumin is a known anti-adipogenic agent for alleviating obesity and related disorders. Comprehensive comparisons of the anti-adipogenic activity of curcumin with other curcuminoids is minimal. This study compared adipogenesis inhibition with curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC), and their underlying mechanisms. We differentiated 3T3-L1 cells in the presence of curcuminoids, to determine lipid accumulation and triglyceride (TG) production. The expression of adipogenic transcription factors and lipogenic proteins was analyzed by Western blot. A significant reduction in Oil red O (ORO) staining was observed in the cells treated with curcuminoids at 20 μM. Inhibition was increased in the order of curcumin < DMC < BDMC. A similar trend was observed in the detection of intracellular TG. Curcuminoids suppressed differentiation by downregulating the expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), leading to the downregulation of the lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). AMP-activated protein kinase α (AMPKα) phosphorylation was also activated by BDMC. Curcuminoids reduced the release of proinflammatory cytokines and leptin in 3T3-L1 cells in a dose-dependent manner, with BDMC showing the greatest potency. BDMC at 20 μM significantly decreased leptin by 72% compared with differentiated controls. Molecular docking computation indicated that curcuminoids, despite having structural similarity, had different interaction positions to PPARγ, C/EBPα, and ACC. The docking profiles suggested a possible interaction of curcuminoids with C/EBPα and ACC, to directly inhibit their expression.


Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 375-382 ◽  
Author(s):  
Sandrine Gremlich ◽  
Christopher Nolan ◽  
Raphaël Roduit ◽  
Rémy Burcelin ◽  
Marie-Line Peyot ◽  
...  

The cellular response to fasting and starvation in tissues such as heart, skeletal muscle, and liver requires peroxisome proliferator-activated receptor-α (PPARα)-dependent up-regulation of energy metabolism toward fatty acid oxidation (FAO). PPARα null (PPARαKO) mice develop hyperinsulinemic hypoglycemia in the fasting state, and we previously showed that PPARα expression is increased in islets at low glucose. On this basis, we hypothesized that enhanced PPARα expression and FAO, via depletion of lipid-signaling molecule(s) for insulin exocytosis, are also involved in the normal adaptive response of the islet to fasting. Fasted PPARαKO mice compared with wild-type mice had supranormal ip glucose tolerance due to increased plasma insulin levels. Isolated islets from the PPARα null mice had a 44% reduction in FAO, normal glucose use and oxidation, and enhanced glucose-induced insulin secretion. In normal rats, fasting for 24 h increased islet PPARα, carnitine palmitoyltransferase 1, and uncoupling protein-2 mRNA expression by 60%, 62%, and 82%, respectively. The data are consistent with the view that PPARα, via transcriptionally up-regulating islet FAO, can reduce insulin secretion, and that this mechanism is involved in the normal physiological response of the pancreatic islet to fasting such that hypoglycemia is avoided.


Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2950 ◽  
Author(s):  
Quancai Sun ◽  
Jie Lin ◽  
Yukui Peng ◽  
Ruichang Gao ◽  
Ye Peng

Flubendiamide, a ryanoid class insecticide, is widely used in agriculture. Several insecticides have been reported to promote adipogenesis. However, the potential influence of flubendiamide on adipogenesis is largely unknown. The current study was therefore to determine the effects of flubendiamide on adipogenesis utilizing the 3T3-L1 adipocytes model. Flubendiamide treatment not only enhanced triglyceride content in 3T3-L1 adipocytes, but also increased the expression of cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT)/enhancer-binding protein α and peroxisome proliferator-activated receptor gamma-γ, two important regulators of adipocyte differentiation. Moreover, the expression of the most important regulator of lipogenesis, acetyl coenzyme A carboxylase, was also increased after flubendiamide treatment. Further study revealed that 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or A769662, two Adenosine 5′-monophosphate (AMP)-activated protein kinase α activators, subverted effects of flubendiamide on enhanced adipogenesis. Together, these results suggest that flubendiamide promotes adipogenesis via an AMPKα-mediated pathway.


2021 ◽  
Vol 49 (11) ◽  
pp. 030006052110550
Author(s):  
Xing Wang ◽  
Shuchun Chen ◽  
Dan Lv ◽  
Zelin Li ◽  
Luping Ren ◽  
...  

Objective To investigate the effect of liraglutide on the browning of white fat and the suppression of obesity via regulating microRNA (miR)-27b in vivo and in vitro. Methods Sprague-Dawley rats were fed a high-fat (HF) diet and 3T3-L1 pre-adipocytes were differentiated into mature white adipocytes. Rats and mature adipocytes were then treated with different doses of liraglutide. The mRNA and protein levels of browning-associated proteins, including uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16), CCAAT enhancer binding protein β (CEBPβ), cell death-inducing DFFA-like effector A (CIDEA) and peroxisome proliferator-activated receptor-γ-coactivator 1α (PGC-1α), were detected using quantitative real-time polymerase chain reaction and Western blotting. Results Liraglutide decreased body weight and reduced the levels of blood glucose, triglyceride and low-density lipoprotein cholesterol in HF diet-fed rats. Liraglutide increased the levels of UCP1, PRDM16, CEBPβ, CIDEA and PGC-1α in vivo and vitro. The levels of miR-27b were upregulated in HF diet-fed rats, whereas liraglutide reduced the levels of miR-27b. In vitro, overexpression of miR-27b decreased the mRNA and protein levels of UCP1, PRDM16, CEBPβ, CIDEA and PGC-1α. Transfection with the miR-27b mimics attenuated the effect of liraglutide on the browning of white adipocytes. Conclusion Liraglutide induced browning of white adipose through regulation of miR-27b.


Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3266-3276 ◽  
Author(s):  
Kim Ravnskjaer ◽  
Michael Boergesen ◽  
Blanca Rubi ◽  
Jan K. Larsen ◽  
Tina Nielsen ◽  
...  

Abstract Fatty acids (FAs) are known to be important regulators of insulin secretion from pancreatic β-cells. FA-coenzyme A esters have been shown to directly stimulate the secretion process, whereas long-term exposure of β-cells to FAs compromises glucose-stimulated insulin secretion (GSIS) by mechanisms unknown to date. It has been speculated that some of these long-term effects are mediated by members of the peroxisome proliferator-activated receptor (PPAR) family via an induction of uncoupling protein-2 (UCP2). In this study we show that adenoviral coexpression of PPARα and retinoid X receptor α (RXRα) in INS-1E β-cells synergistically and in a dose- and ligand-dependent manner increases the expression of known PPARα target genes and enhances FA uptake and β-oxidation. In contrast, ectopic expression of PPARγ/RXRα increases FA uptake and deposition as triacylglycerides. Although the expression of PPARα/RXRα leads to the induction of UCP2 mRNA and protein, this is not accompanied by reduced hyperpolarization of the mitochondrial membrane, indicating that under these conditions, increased UCP2 expression is insufficient for dissipation of the mitochondrial proton gradient. Importantly, whereas expression of PPARγ/RXRα attenuates GSIS, the expression of PPARα/RXRα potentiates GSIS in rat islets and INS-1E cells without affecting the mitochondrial membrane potential. These results show a strong subtype specificity of the two PPAR subtypes α and γ on lipid partitioning and insulin secretion when systematically compared in a β-cell context.


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