scholarly journals Mechanisms Regulating Repression of Haptoglobin Production by Peroxisome Proliferator-Activated Receptor-γ Ligands in Adipocytes

Endocrinology ◽  
2010 ◽  
Vol 151 (2) ◽  
pp. 586-594 ◽  
Author(s):  
Cecile Vernochet ◽  
Kathryn E. Davis ◽  
Philipp E. Scherer ◽  
Stephen R. Farmer
Keyword(s):  
Adipose Tissue ◽  
Reporter Gene ◽  
Gene Transcription ◽  
Acute Phase ◽  
White Adipose Tissue ◽  
Binding Protein ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Haptoglobin Gene

Obesity leads to inflammation of white adipose tissue involving enhanced secretion of cytokines and acute-phase proteins in response in part to the accumulation of excess lipids in adipocytes. Haptoglobin is an acute-phase reactant secreted by white adipose tissue and induced by inflammatory cytokines such as TNFα. In this study, we investigated the mechanisms regulating haptoglobin expression in adipocytes. Peroxisome proliferator-activated receptor (PPAR)-γ agonists such as thiazolidinediones (TZDs) as well as non-TZD ligands can repress in vitro and in vivo haptoglobin expression in adipocytes and also prevent its induction by TNFα. This action requires direct involvement of PPARγ in regulating haptoglobin gene transcription because mutation of critical amino acids within helix 7 of the ligand-binding domain of PPARγ prevents repression of the haptoglobin gene by the synthetic ligands. Chromatin immunoprecipitation analysis shows active binding of PPARγ to a distal region of the haptoglobin promoter, which contains putative PPARγ binding sites. Additionally, PPARγ induces transcription of a luciferase reporter gene when driven by the distal promoter region of the haptoglobin gene, and TZD treatment significantly reduces the extent of this induction. Furthermore, the mutated PPARγ is incapable of enhancing luciferase activity in these in vitro reporter gene assays. In contrast to other adipokines repressed by TZDs such as resistin and chemerin, repression of haptoglobin does not require either CCAAT/enhancer-binding protein C/EBPα or the corepressors C-terminal binding protein 1 or 2. These data are consistent with a model in which synthetic PPARγ ligands selectively activate PPARγ bound to the haptoglobin gene promoter to arrest haptoglobin gene transcription.

scholarly journals Trans-10, cis-12 conjugated linoleic acid causes inflammation and delipidation of white adipose tissue in mice: a microarray and histological analysis

2006 ◽  
Vol 27 (3) ◽  
pp. 282-294 ◽  
Author(s):  
P. Christopher LaRosa ◽  
Jess Miner ◽  
Yuannan Xia ◽  
You Zhou ◽  
Steve Kachman ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
White Adipose Tissue ◽  
Binding Protein ◽  
Uncoupling Protein ◽  
Peroxisome Proliferator ◽  
Functional Responses ◽  
Peroxisome Proliferator Activated Receptor ◽  
Transcript Levels

A combined histological and microarray analysis of the white adipose tissue (WAT) of mice fed trans-10, cis-12 conjugated linoleic acid (t10c12 CLA) was performed to better define functional responses. Mice fed t10c12 CLA for 14 days lost 85% of WAT mass, 95% of adipocyte lipid droplet volume, and 15 or 47% of the number of adipocytes and total cells, respectively. Microarray profiling of replicated pools ( n = 2 per day × diet) of control and treated mice ( n = 140) at seven time points after 1–17 days of t10c12 CLA feeding found between 2,682 and 4,216 transcript levels changed by twofold or more. Transcript levels for genes involved in glucose and fatty acid import or biosynthesis were significantly reduced. Highly expressed transcripts for lipases were significantly reduced but still abundant. Increased levels of mRNAs for two key thermogenesis proteins, uncoupling protein 1 and carnitine palmitoyltransferase 1, may have increased energy expenditures. Significant reductions of mRNAs for major adipocyte regulatory factors, including peroxisome proliferator activated receptor-γ, sterol regulatory binding protein 1, CAAT/enhancer binding protein-α, and lipin 1 were correlated with the reduced transcript levels for key metabolic pathways in the WAT. A prolific inflammation response was indicated by the 2- to 100-fold induction of many cytokine transcripts, including those for IL-6, IL-1β, TNF ligands, and CXC family members, and an increased density of macrophages. The mRNA changes suggest that a combination of cell loss, increased energy expenditure, and residual transport of lipids out of the adipocytes may account for the cumulative mass loss observed.

scholarly journals Adipogenic role of alternatively activated macrophages in β-adrenergic remodeling of white adipose tissue

2016 ◽  
Vol 310 (1) ◽  
pp. R55-R65 ◽  
Author(s):  
Yun-Hee Lee ◽  
Sang-Nam Kim ◽  
Hyun-Jung Kwon ◽  
Krishna Rao Maddipati ◽  
James G. Granneman
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
De Novo ◽  
Flow Cytometric Analysis ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Physical Relationship ◽  
Alternatively Activated Macrophages

De novo brown adipogenesis involves the proliferation and differentiation of progenitors, yet the mechanisms that guide these events in vivo are poorly understood. We previously demonstrated that treatment with a β3-adrenergic receptor (ADRB3) agonist triggers brown/beige adipogenesis in gonadal white adipose tissue following adipocyte death and clearance by tissue macrophages. The close physical relationship between adipocyte progenitors and tissue macrophages suggested that the macrophages that clear dying adipocytes might generate proadipogenic factors. Flow cytometric analysis of macrophages from mice treated with CL 316,243 identified a subpopulation that contained elevated lipid and expressed CD44. Lipidomic analysis of fluorescence-activated cell sorting-isolated macrophages demonstrated that CD44+ macrophages contained four- to five-fold higher levels of the endogenous peroxisome-proliferator activated receptor gamma (PPARγ) ligands 9-hydroxyoctadecadienoic acid (HODE), and 13-HODE compared with CD44− macrophages. Gene expression profiling and immunohistochemistry demonstrated that ADRB3 agonist treatment upregulated expression of ALOX15, the lipoxygenase responsible for generating 9-HODE and 13-HODE. Using an in vitro model of adipocyte efferocytosis, we found that IL-4-primed tissue macrophages accumulated lipid from dying fat cells and upregulated expression of Alox15. Furthermore, treatment of differentiating adipocytes with 9-HODE and 13-HODE potentiated brown/beige adipogenesis. Collectively, these data indicate that noninflammatory removal of adipocyte remnants and coordinated generation of PPARγ ligands by M2 macrophages provides localized adipogenic signals to support de novo brown/beige adipogenesis.

scholarly journals PPARγ-K107 SUMOylation regulates insulin sensitivity but not adiposity in mice

2018 ◽  
Vol 115 (48) ◽  
pp. 12102-12111 ◽  
Author(s):  
Takeshi Katafuchi ◽  
William L. Holland ◽  
Rahul K. Kollipara ◽  
Ralf Kittler ◽  
David J. Mangelsdorf ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
White Adipose Tissue ◽  
Adipocyte Differentiation ◽  
Mutant Mice ◽  
Covalent Attachment ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

The nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipocyte differentiation and is the target for the insulin-sensitizing thiazolidinedione (TZD) drugs used to treat type 2 diabetes. In cell-based in vitro studies, the transcriptional activity of PPARγ is inhibited by covalent attachment of small ubiquitin-related modifier (SUMOylation) at K107 in its N terminus. However, whether this posttranslational modification is relevant in vivo remains unclear. Here, using mice homozygous for a mutation (K107R) that prevents SUMOylation at this position, we demonstrate that PPARγ is SUMOylated at K107 in white adipose tissue. We further show that in the context of diet-induced obesity PPARγ-K107R–mutant mice have enhanced insulin sensitivity without the corresponding increase in adiposity that typically accompanies PPARγ activation by TZDs. Accordingly, the PPARγ-K107R mutation was weaker than TZD treatment in stimulating adipocyte differentiation in vitro. Moreover, we found that both the basal and TZD-dependent transcriptomes of inguinal and epididymal white adipose tissue depots were markedly altered in the K107R-mutant mice. We conclude that PPARγ SUMOylation at K107 is physiologically relevant and may serve as a pharmacologic target for uncoupling PPARγ’s beneficial insulin-sensitizing effect from its adverse effect of weight gain.

scholarly journals Contribution of PGC-1α to Obesity- and Caloric Restriction-Related Physiological Changes in White Adipose Tissue

2021 ◽  
Vol 22 (11) ◽  
pp. 6025
Author(s):  
Masaki Kobayashi ◽  
Yusuke Deguchi ◽  
Yuka Nozaki ◽  
Yoshikazu Higami
Keyword(s):  
Adipose Tissue ◽  
Caloric Restriction ◽  
White Adipose Tissue ◽  
Mitochondrial Gene ◽  
Energy Resource ◽  
Peroxisome Proliferator ◽  
Physiological Changes ◽  
Mitochondrial Gene Expression ◽  
Peroxisome Proliferator Activated Receptor ◽  
White Adipocytes

Peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α) regulates mitochondrial DNA replication and mitochondrial gene expression by interacting with several transcription factors. White adipose tissue (WAT) mainly comprises adipocytes that store triglycerides as an energy resource and secrete adipokines. The characteristics of WAT vary in response to systemic and chronic metabolic alterations, including obesity or caloric restriction. Despite a small amount of mitochondria in white adipocytes, accumulated evidence suggests that mitochondria are strongly related to adipocyte-specific functions, such as adipogenesis and lipogenesis, as well as oxidative metabolism for energy supply. Therefore, PGC-1α is expected to play an important role in WAT. In this review, we provide an overview of the involvement of mitochondria and PGC-1α with obesity- and caloric restriction-related physiological changes in adipocytes and WAT.

scholarly journals Angiogenic Deficiency and Adipose Tissue Dysfunction Are Associated with Macrophage Malfunction in SIRT1−/− Mice

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1706-1716 ◽  
Author(s):  
Fen Xu ◽  
David Burk ◽  
Zhanguo Gao ◽  
Jun Yin ◽  
Xia Zhang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Adipocyte Differentiation ◽  
Nuclear Factor Κb ◽  
The Body ◽  
Sirtuin 1 ◽  
Vascular Density ◽  
Peroxisome Proliferator ◽  
Wild Type ◽  
Peroxisome Proliferator Activated Receptor

The histone deacetylase sirtuin 1 (SIRT1) inhibits adipocyte differentiation and suppresses inflammation by targeting the transcription factors peroxisome proliferator-activated receptor γ and nuclear factor κB. Although this suggests that adiposity and inflammation should be enhanced when SIRT1 activity is inactivated in the body, this hypothesis has not been tested in SIRT1 null (SIRT1−/−) mice. In this study, we addressed this issue by investigating the adipose tissue in SIRT1−/− mice. Compared with their wild-type littermates, SIRT1 null mice exhibited a significant reduction in body weight. In adipose tissue, the average size of adipocytes was smaller, the content of extracellular matrix was lower, adiponectin and leptin were expressed at 60% of normal level, and adipocyte differentiation was reduced. All of these changes were observed with a 50% reduction in capillary density that was determined using a three-dimensional imaging technique. Except for vascular endothelial growth factor, the expression of several angiogenic factors (Pdgf, Hgf, endothelin, apelin, and Tgf-β) was reduced by about 50%. Macrophage infiltration and inflammatory cytokine expression were 70% less in the adipose tissue of null mice and macrophage differentiation was significantly inhibited in SIRT1−/− mouse embryonic fibroblasts in vitro. In wild-type mice, macrophage deletion led to a reduction in vascular density. These data suggest that SIRT1 controls adipose tissue function through regulation of angiogenesis, whose deficiency is associated with macrophage malfunction in SIRT1−/− mice. The study supports the concept that inflammation regulates angiogenesis in the adipose tissue.

scholarly journals Current Progress in Adipose Tissue Biology: Implications in Obesity and Its Comorbidities

2020 ◽  
Vol 12 (2) ◽  
pp. 85-101
Author(s):  
Anna Meiliana ◽  
Nurrani Mustika Dewi ◽  
Andi Wijaya
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Uncoupling Protein ◽  
Common Factor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
Brown Adipose ◽  
Key Factor ◽  
Beige Fat

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

scholarly journals Regulation of Peroxisome Proliferator-Activated Receptor Pathway During Torpor in the Garden Dormouse, Eliomys quercinus

2020 ◽  
Vol 11 ◽  
Author(s):  
Alexander J. Watts ◽  
Samantha M. Logan ◽  
Anna Kübber-Heiss ◽  
Annika Posautz ◽  
Gabrielle Stalder ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
White Adipose Tissue ◽  
Binding Activity ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Dna Binding Activity ◽  
Garden Dormouse ◽  
Eliomys Quercinus

Differential levels of n-6 and n-3 essential polyunsaturated fatty acids (PUFAs) are incorporated into the hibernator’s diet in the fall season preceding prolonged, multi-days bouts of torpor, known as hibernation. Peroxisome proliferator-activated receptor (PPAR) transcriptional activators bind lipids and regulate genes involved in fatty acid transport, beta-oxidation, ketogenesis, and insulin sensitivity; essential processes for survival during torpor. Thus, the DNA-binding activity of PPARα, PPARδ, PPARγ, as well as the levels of PPARγ coactivator 1α (PGC-1α) and L-fatty acid binding protein (L-FABP) were investigated in the hibernating garden dormouse (Eliomys quercinus). We found that dormice were hibernating in a similar way regardless of the n-6/n-3 PUFA diets fed to the animals during the fattening phase prior to hibernation. Further, metabolic rates and body mass loss during hibernation did not differ between dietary groups, despite marked differences in fatty acid profiles observed in white adipose tissue prior and at mid-hibernation. Overall, maintenance of PPAR DNA-binding activity was observed during torpor, and across three n-6/n-3 ratios, suggesting alternate mechanisms for the prioritization of lipid catabolism during torpor. Additionally, while no change was seen in L-FABP, significantly altered levels of PGC-1α were observed within the white adipose tissue and likely contributes to enhanced lipid metabolism when the diet favors n-6 PUFAs, i.e., high n-6/n-3 ratio, in both the torpid and euthermic state. Altogether, the maintenance of lipid metabolism during torpor makes it likely that consistent activity or levels of the investigated proteins are in aid of this metabolic profile.

scholarly journals Unripe Rubus coreanus Miquel Extract Containing Ellagic Acid Promotes Lipolysis and Thermogenesis In Vitro and In Vivo

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5954
Author(s):  
Kyeong Jo Kim ◽  
Eui-Seon Jeong ◽  
Ki Hoon Lee ◽  
Ju-Ryun Na ◽  
Soyi Park ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Ellagic Acid ◽  
Uncoupling Protein ◽  
Hormone Sensitive Lipase ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Rubus Coreanus ◽  
Associated Proteins

Previously, we demonstrated that a 5% ethanol extract of unripe Rubus coreanus (5-uRCK) and ellagic acid has hypocholesterolemic and antiobesity activity, at least partially mediated by the downregulation of adipogenic and lipogenic gene expression in high-fat diet (HFD)-fed animals. The present study investigated the thermogenic and lipolytic antiobesity effects of 5-uRCK and ellagic acid in HFD-induced obese C57BL/6 mice and explored its mechanism of action. Mice fed an HFD received 5-uRCK or ellagic acid as a post-treatment or pretreatment. Both post-treated and pretreated mice showed significant reductions in body weight and adipose tissue mass compared to the HFD-fed mice. The protein levels of lipolysis-associated proteins, such as adipose triglyceride lipase (ATGL), phosphorylated hormone-sensitive lipase (p-HSL), and perilipin1 (PLIN1), were significantly increased in both the 5-uRCK- and ellagic acid-treated mouse epididymal white adipose tissue (eWAT). Additionally, thermogenesis-associated proteins, such as peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyl transferase-1 (CPT1), uncoupling protein 1 (UCP1), and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), in inguinal white adipose tissue (ingWAT) were clearly increased in both the 5-uRCK- and ellagic acid-treated mice compared to HFD-fed mice. These results suggest that 5-uRCK and ellagic acid are effective for suppressing body weight gain and enhancing the lipid profile.

Effects of Deep Sea Water on Anti-Obesity Properties in Induction of Beige Adipocytes

2019 ◽  
Vol 13 (1) ◽  
pp. 38-48
Author(s):  
Samihah Z.M. Nani ◽  
Abubakar Jaafar ◽  
Fadzilah A.A. Majid ◽  
Akbariah Mahdzir ◽  
Md. Nor Musa
Keyword(s):  
Adipose Tissue ◽  
Deep Sea ◽  
Sea Water ◽  
Binding Protein ◽  
Uncoupling Protein ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Fatty Acid Binding ◽  
Deep Sea Water ◽  
Beige Adipocytes

Objective: Deep sea water (DSW) accumulates many scientific shreds of evidence in treating obesity. Previous studies indicated that it reduces white adipose tissue (WAT) and body weight. WAT is energy storage fat, while beige adipose tissue is energy supply fat. In this study, the effects of DSW in the induction of beige adipocytes from mouse adipose tissue-derived stromal vascular fraction (SVF) cells are determined. Methods: Adipose tissue-derived SVF cells were isolated from mice and used for induction of beige adipocytes and treated with DSW at several concentrations. Results: During the course of beige adipocytes differentiation, DSW treatment increased lipid accumulation and upregulated adipogenic genes markers expression such as peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein a (C/EBP-α), and fatty acid binding protein 4 (FABP4), and also upregulated thermogenic genes markers such as the uncoupling protein 1 (UCP-1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and cell deathinducing DFFA-like effector A (Cidea) in beige adipocytes. Conclusion: DSW has the potential to promote browning of WAT and upregulates the thermogenic genes that are responsible for energy expenditure.

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