Identification of hepatic transcriptional changes in insulin-resistant rats treated with peroxisome proliferator activated receptor-alpha agonists

2003 ◽  
Vol 30 (3) ◽  
pp. 317-329 ◽  
Author(s):  
KS Frederiksen ◽  
EM Wulf ◽  
K Wassermann ◽  
P Sauerberg ◽  
J Fleckner
Keyword(s):  
Insulin Resistance ◽  
Tyrosine Phosphatase ◽  
Peroxisome Proliferator ◽  
Sprague Dawley ◽  
High Fat ◽  
Transcriptional Responses ◽  
Ppar Alpha ◽  
Peroxisome Proliferator Activated Receptor

Peroxisome proliferator activated receptor (PPAR)-alpha controls the expression of multiple genes involved in lipid metabolism, and activators of PPAR-alpha, such as fibrates, are commonly used drugs in the treatment of hypertriglyceridemia and other dyslipidemic states. Recent data have also suggested a role for PPAR-alpha in insulin resistance and glucose homeostasis. In the present study, we have assessed the transcriptional and physiological responses to PPAR-alpha activation in a diet-induced rat model of insulin resistance. The two PPAR-alpha activators, fenofibrate and Wy-14643, were dosed at different concentrations in high-fat fed Sprague-Dawley rats, and the transcriptional responses were examined in liver using cDNA microarrays. In these analyses, 98 genes were identified as being regulated by both compounds. From this pool of genes, 27 correlated to the observed effect on plasma insulin, including PPAR-alpha itself and the leukocyte antigen-related protein tyrosine phosphatase (PTP-LAR). PTP-LAR was downregulated by both compounds, and showed upregulation as a result of the high-fat feeding. This regulation was also observed at the protein level. Furthermore, downregulation of PTP-LAR by fenofibric acid was demonstrated in rat FaO hepatoma cells in vitro, indicating that the observed regulation of PTP-LAR by fenofibrate and Wy-14643 in vivo is mediated as a direct effect of the PPAR agonists on the hepatocytes. PTP-LAR is one of the first genes involved in insulin receptor signaling to be shown to be regulated by PPAR-alpha agonists. These data suggest that factors apart from skeletal muscle lipid supply may influence PPAR-alpha-mediated amelioration of insulin resistance.

scholarly journals Liraglutide suppresses obesity and promotes browning of white fat via miR-27b in vivo and in vitro

2021 ◽  
Vol 49 (11) ◽  
pp. 030006052110550
Author(s):  
Xing Wang ◽  
Shuchun Chen ◽  
Dan Lv ◽  
Zelin Li ◽  
Luping Ren ◽  
...  
Keyword(s):  
Uncoupling Protein ◽  
Density Lipoprotein ◽  
Peroxisome Proliferator ◽  
Sprague Dawley ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
White Adipocytes ◽  
White Fat

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.

scholarly journals Curcumin improves glycolipid metabolism through regulating peroxisome proliferator activated receptor γ signalling pathway in high-fat diet-induced obese mice and 3T3-L1 adipocytes

2017 ◽  
Vol 4 (11) ◽  
pp. 170917 ◽  
Author(s):  
Yanyun Pan ◽  
Dandan Zhao ◽  
Na Yu ◽  
Tian An ◽  
Jianan Miao ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Fasting Blood Glucose ◽  
Signalling Pathway ◽  
Peroxisome Proliferator ◽  
Obese Mice ◽  
High Fat ◽  
Peroxisome Proliferator Activated Receptor ◽  
Glycolipid Metabolism

Curcumin is an active component derived from Curcuma longa L. which is a traditional Chinese medicine that is widely used for treating metabolic diseases through regulating different molecular pathways. Here, in this study, we aimed to comprehensively investigate the effects of curcumin on glycolipid metabolism in vivo and in vitro and then determine the underlying mechanism. Male C57BL/6 J obese mice and 3T3-L1 adipocytes were used for in vivo and in vitro study, respectively. Our results demonstrated that treatment with curcumin for eight weeks decreased body weight, fat mass and serum lipid profiles. Meanwhile, it lowered fasting blood glucose and increased the insulin sensitivity in high-fat diet-induced obese mice. In addition, curcumin stimulated lipolysis and improved glycolipid metabolism through upregulating the expressions of adipose triglyceride lipase and hormone-sensitive lipase, peroxisome proliferator activated receptor γ/α (PPARγ/α) and CCAAT/enhancer binding proteinα (C/EBPα) in adipose tissue of the mice. In differentiated 3T3-L1 cells, curcumin reduced glycerol release and increased glucose uptake via upregulating PPARγ and C/EBPα. We concluded that curcumin has the potential to improve glycolipid metabolism disorders caused by obesity through regulating PPARγ signalling pathway.

scholarly journals Skeletal muscle mitochondrial and metabolic responses to a high-fat diet in female rats bred for high and low aerobic capacity

2010 ◽  
Vol 35 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Scott P. Naples ◽  
Sarah J. Borengasser ◽  
R. Scott. Rector ◽  
Grace M. Uptergrove ◽  
E. Matthew Morris ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Female Rats ◽  
Mitochondrial Morphology ◽  
Peroxisome Proliferator ◽  
High Fat ◽  
Transcriptional Responses ◽  
Peroxisome Proliferator Activated Receptor

Rats selected artificially to be low-capacity runners (LCR) possess a metabolic syndrome phenotype that is worsened by a high-fat diet (HFD), whereas rats selected to be high-capacity runners (HCR) are protected against HFD-induced obesity and insulin resistance. This study examined whether protection against, or susceptibility to, HFD-induced insulin resistance in the HCR–LCR strains is associated with contrasting metabolic adaptations in skeletal muscle. HCR and LCR rats (generation 20; n = 5–6; maximum running distance ∼1800 m vs. ∼350 m, respectively (p < 0.0001)) were divided into HFD (71.6% energy from fat) or normal chow (NC) (16.7% energy from fat) groups for 7 weeks (from 24 to 31 weeks of age). Skeletal muscle (red gastrocnemius) mitochondrial-fatty acid oxidation (FAO), mitochondrial-enzyme activity, mitochondrial-morphology, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and peroxisome proliferator-activated receptor δ (PPARδ) expression and insulin sensitivity (intraperitoneal glucose tolerance tests) were measured. The HFD caused increased adiposity and reduced insulin sensitivity only in the LCR and not the HCR strain. Isolated mitochondria from the HCR skeletal muscle displayed a 2-fold-higher rate of FAO on NC, but both groups increased FAO following HFD. PGC-1α mRNA expression and superoxide dismutase activity were significantly reduced with the HFD in the LCR rats, but not in the HCR rats. PPARδ expression did not differ between strains or dietary conditions. These results do not provide a clear connection between protection of insulin sensitivity and HFD-induced adaptive changes in mitochondrial function or transcriptional responses but do not dismiss the possibility that elevated mitochondrial FAO in the HCR may play a protective role.

scholarly journals 8-Hydroxyeicosapentaenoic Acid Decreases Plasma and Hepatic Triglycerides via Activation of Peroxisome Proliferator-Activated Receptor Alpha in High-Fat Diet-Induced Obese Mice

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hidetoshi Yamada ◽  
Sayaka Kikuchi ◽  
Mayuka Hakozaki ◽  
Kaori Motodate ◽  
Nozomi Nagahora ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Peroxisome Proliferator ◽  
High Fat ◽  
Peroxisome Proliferator Activated Receptor ◽  
Expression Of Genes ◽  
Ppar Ligand ◽  
Obesity In Mice ◽  
Ligand Activity

PPARs regulate the expression of genes involved in lipid homeostasis. PPARs serve as molecular sensors of fatty acids, and their activation can act against obesity and metabolic syndromes. 8-Hydroxyeicosapentaenoic acid (8-HEPE) acts as a PPAR ligand and has higher activity than EPA. However, to date, the PPAR ligand activity of 8-HEPE has only been demonstratedin vitro. Here, we investigated its ligand activityin vivoby examining the effect of 8-HEPE treatment on high fat diet-induced obesity in mice. After the 4-week treatment period, the levels of plasma and hepatic triglycerides in the 8-HEPE-fed mice were significantly lower than those in the HFD-fed mice. The expression of genes regulated by PPARαwas significantly increased in 8-HEPE-fed mice compared to those that received only HFD. Additionally, the level of hepatic palmitic acid in 8-HEPE-fed mice was significantly lower than in HFD-fed mice. These results suggested that intake of 8-HEPE induced PPARαactivation and increased catabolism of lipids in the liver. We found no significant differences between EPA-fed mice and HFD-fed mice. We demonstrated that 8-HEPE has a larger positive effect on metabolic syndrome than EPA and that 8-HEPE acts by inducing PPARαactivation in the liver.

scholarly journals Inhibiting myeloperoxidase prevents onset and reverses established high-fat diet-induced microvascular insulin resistance

2019 ◽  
Vol 317 (6) ◽  
pp. E1063-E1069 ◽  
Author(s):  
Weidong Chai ◽  
Kevin Aylor ◽  
Zhenqi Liu ◽  
Li-Ming Gan ◽  
Erik Michaëlsson ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Disease Risk ◽  
Therapeutic Potential ◽  
Cardiovascular Disease Risk ◽  
Sprague Dawley ◽  
High Fat

A high-fat diet (HFD) can rapidly recruit neutrophils to insulin target tissues and within days induce microvascular insulin resistance (IR). Myeloperoxidase (MPO) is highly enriched in neutrophils, can inhibit nitric oxide-mediated vasorelaxation in vitro and is associated with increased cardiovascular disease risk. AZD5904 irreversibly inhibits MPO and in human clinical trials. MPO knockout, or chemical inhibition, blunts HFD-induced metabolic IR in mice. Whether MPO affects microvascular IR or muscle metabolic insulin sensitivity in vivo is unknown. We used contrast-enhanced ultrasound and the euglycemic insulin clamp to test whether inhibiting MPO could prevent the development or reverse established HFD-induced metabolic and/or microvascular IR in Sprague-Dawley rats. Two weeks of HFD feeding blocked insulin-mediated skeletal muscle capillary recruitment, inhibited glucose utilization, and insulin signaling to muscle. Continuous subcutaneous AZD5904 infusion during the 2 wk selectively blocked HFD’s microvascular effect. Furthermore, AZD5904 infusion during the last 2 of 4 wk of HFD feeding restored microvascular insulin sensitivity but not metabolic IR. We conclude that inhibiting MPO selectively improves vascular IR. This selective microvascular effect may connote a therapeutic potential for MPO inhibition in the prevention of vascular disease/dysfunction seen in IR humans.

scholarly journals Mineralocorticoid Receptor Blockade Improves Insulin Sensitivity in the Rat Heart and a Possible Molecular Mechanism

2016 ◽  
Vol 39 (3) ◽  
pp. 860-870 ◽  
Author(s):  
Mei Wang ◽  
Yongjun Li ◽  
Kun Zhou ◽  
Guoru Zhang ◽  
Yaling Wang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
P38 Mapk ◽  
Mineralocorticoid Receptor ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Mapk Inhibitor

Background/Aims: Extensive research has explored the role of aldosterone in insulin resistance. Recent evidence suggests that the mineralocorticoid receptor (MR) mediates aldosterone-induced dysregulation of cytokines, and most of this research has focused on adjustments in fat tissue and adipocytes. However, the direct effect of MR blockade on insulin resistance in cardiomyocytes remains largely unknown. In the present study, we investigated whether MR blockade improves insulin-sensitizing factors in insulin-resistant rats and attenuates the dysregulation of the aldosterone-related transport of adiponectin and glucose in cardiomyocytes and examined the underlying mechanisms. Methods: The effects of aldosterone, MR inhibitors (e.g., eplerenone), a peroxisome proliferator-activated receptor (PPAR) α agonist, and a p38 mitogen-activated protein kinase (MAPK) inhibitor on adiponectin and glucose transport were studied at the mRNA and protein levels in vitro and in vivo. Results: Our data revealed that aldosterone reduced the expression of adiponectin and inhibited the transport of glucose in cardiomyocytes and that MR blockade reversed these affects. In vivo, MR blockade improved insulin-sensitive parameters and increased adiponectin expression in the myocardia of high-fat diet rats. Furthermore, aldosterone promoted p38MAPK expression but negatively affected PPARα expression, and the downregulation of adiponectin by aldosterone was reversed by MR blockade, a PPARα agonist, and a p38 MAPK inhibitor. Conclusion: The above results suggested that aldosterone promoted insulin resistance in the heart and that this effect could be partly reversed by MR blockade through signal transduction in the P38 MAPK pathway and PPARα.

scholarly journals Labisia pumilaUpregulates Peroxisome Proliferator-Activated Receptor Gamma Expression in Rat Adipose Tissues and 3T3-L1 Adipocytes

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Fazliana Mansor ◽  
Harvest F. Gu ◽  
Claes-Göran Östenson ◽  
Louise Mannerås-Holm ◽  
Elisabet Stener-Victorin ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Polycystic Ovary ◽  
Mrna Level ◽  
Water Extract ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels

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.

scholarly journals Adipocyte PHLPP2 inhibition prevents obesity-induced fatty liver

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
KyeongJin Kim ◽  
Jin Ku Kang ◽  
Young Hoon Jung ◽  
Sang Bae Lee ◽  
Raffaela Rametta ◽  
...  
Keyword(s):  
Fatty Liver ◽  
Whole Body ◽  
Acid Oxidation ◽  
Chow Diet ◽  
Peroxisome Proliferator ◽  
Obese Mice ◽  
Ph Domain ◽  
Peroxisome Proliferator Activated Receptor

AbstractIncreased adiposity confers risk for systemic insulin resistance and type 2 diabetes (T2D), but mechanisms underlying this pathogenic inter-organ crosstalk are incompletely understood. We find PHLPP2 (PH domain and leucine rich repeat protein phosphatase 2), recently identified as the Akt Ser473 phosphatase, to be increased in adipocytes from obese mice. To identify the functional consequence of increased adipocyte PHLPP2 in obese mice, we generated adipocyte-specific PHLPP2 knockout (A-PHLPP2) mice. A-PHLPP2 mice show normal adiposity and glucose metabolism when fed a normal chow diet, but reduced adiposity and improved whole-body glucose tolerance as compared to Cre- controls with high-fat diet (HFD) feeding. Notably, HFD-fed A-PHLPP2 mice show increased HSL phosphorylation, leading to increased lipolysis in vitro and in vivo. Mobilized adipocyte fatty acids are oxidized, leading to increased peroxisome proliferator-activated receptor alpha (PPARα)-dependent adiponectin secretion, which in turn increases hepatic fatty acid oxidation to ameliorate obesity-induced fatty liver. Consistently, adipose PHLPP2 expression is negatively correlated with serum adiponectin levels in obese humans. Overall, these data implicate an adipocyte PHLPP2-HSL-PPARα signaling axis to regulate systemic glucose and lipid homeostasis, and suggest that excess adipocyte PHLPP2 explains decreased adiponectin secretion and downstream metabolic consequence in obesity.

scholarly journals The lipid-lowering drug fenofibrate combined with si-HOTAIR can effectively inhibit the proliferation of gliomas

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wei Zhu ◽  
Hongyang Zhao ◽  
Fenfen Xu ◽  
Bin Huang ◽  
Xiaojing Dai ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Glioma Cells ◽  
Lipid Lowering ◽  
Fibric Acid Derivative ◽  
Peroxisome Proliferator ◽  
Glioma Invasion ◽  
Peroxisome Proliferator Activated Receptor ◽  
Lncrna Hotair

Abstract Background Fenofibrate is a fibric acid derivative known to have a lipid-lowering effect. Although fenofibrate-induced peroxisome proliferator-activated receptor alpha (PPARα) transcription activation has been shown to play an important role in the malignant progression of gliomas, the underlying mechanisms are poorly understood. Methods In this study, we analyzed TCGA database and found that there was a significant negative correlation between the long noncoding RNA (lncRNA) HOTAIR and PPARα. Then, we explored the molecular mechanism by which lncRNA HOTAIR regulates PPARα in cell lines in vitro and in a nude mouse glioma model in vivo and explored the effect of the combined application of HOTAIR knockdown and fenofibrate treatment on glioma invasion. Results For the first time, it was shown that after knockdown of the expression of HOTAIR in gliomas, the expression of PPARα was significantly upregulated, and the invasion and proliferation ability of gliomas were obviously inhibited. Then, glioma cells were treated with both the PPARα agonist fenofibrate and si-HOTAIR, and the results showed that the proliferation and invasion of glioma cells were significantly inhibited. Conclusions Our results suggest that HOTAIR can negatively regulate the expression of PPARα and that the combination of fenofibrate and si-HOTAIR treatment can significantly inhibit the progression of gliomas. This introduces new ideas for the treatment of gliomas.

scholarly journals The Novel Role of PGC1α in Bone Metabolism

2021 ◽  
Vol 22 (9) ◽  
pp. 4670
Author(s):  
Cinzia Buccoliero ◽  
Manuela Dicarlo ◽  
Patrizia Pignataro ◽  
Francesco Gaccione ◽  
Silvia Colucci ◽  
...  
Keyword(s):  
Bone Metabolism ◽  
Osteoblastic Differentiation ◽  
In Vivo Studies ◽  
Peroxisome Proliferator ◽  
Sirtuin 3 ◽  
Peroxisome Proliferator Activated Receptor ◽  
Increased Risk

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) is a protein that promotes transcription of numerous genes, particularly those responsible for the regulation of mitochondrial biogenesis. Evidence for a key role of PGC1α in bone metabolism is very recent. In vivo studies showed that PGC1α deletion negatively affects cortical thickness, trabecular organization and resistance to flexion, resulting in increased risk of fracture. Furthermore, in a mouse model of bone disease, PGC1α activation stimulates osteoblastic gene expression and inhibits atrogene transcription. PGC1α overexpression positively affects the activity of Sirtuin 3, a mitochondrial nicotinammide adenina dinucleotide (NAD)-dependent deacetylase, on osteoblastic differentiation. In vitro, PGC1α overexpression prevents the reduction of mitochondrial density, membrane potential and alkaline phosphatase activity caused by Sirtuin 3 knockdown in osteoblasts. Moreover, PGC1α influences the commitment of skeletal stem cells towards an osteogenic lineage, while negatively affects marrow adipose tissue accumulation. In this review, we will focus on recent findings about PGC1α action on bone metabolism, in vivo and in vitro, and in pathologies that cause bone loss, such as osteoporosis and type 2 diabetes.

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