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 Diabetic human adipose tissue-derived mesenchymal stem cells fail to differentiate in functional adipocytes

2016 ◽  
Vol 242 (10) ◽  
pp. 1079-1085 ◽  
Author(s):  
Ignazio Barbagallo ◽  
Giovanni Li Volti ◽  
Fabio Galvano ◽  
Guido Tettamanti ◽  
Francesca R Pluchinotta ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Adipose Tissue ◽  
In Vitro Study ◽  
Human Adipose Tissue ◽  
Sirtuin 1 ◽  
Diabetic Patients ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Adipose tissue dysfunction represents a hallmark of diabetic patients and is a consequence of the altered homeostasis of this tissue. Mesenchymal stem cells (MSCs) and their differentiation into adipocytes contribute significantly in maintaining the mass and function of adult adipose tissue. The aim of this study was to evaluate the differentiation of MSCs from patients suffering type 2 diabetes (dASC) and how such process results in hyperplasia or rather a stop of adipocyte turnover resulting in hypertrophy of mature adipocytes. Our results showed that gene profile of all adipogenic markers is not expressed in diabetic cells after differentiation indicating that diabetic cells fail to differentiate into adipocytes. Interestingly, delta like 1, peroxisome proliferator-activated receptor alpha, and interleukin 1β were upregulated whereas Sirtuin 1 and insulin receptor substrate 1 gene expression were found downregulated in dASC compared to cells obtained from healthy subjects. Taken together our data indicate that dASC lose their ability to differentiate into mature and functional adipocytes. In conclusion, our in vitro study is the first to suggest that diabetic patients might develop obesity through a hypertrophy of existing mature adipocytes due to failure turnover of adipose tissue. Impact statement In the present manuscript, we evaluated the differentiative potential of mesenchymal stem cells (MSCs) in adipocytes obtained from healthy and diabetic patients. This finding could be of great potential interest for the field of obesity in order to exploit such results to further understand the pathophysiological processes underlying metabolic syndrome. In particular, inflammation in diabetic patients causes a dysfunction in MSCs differentiation and a decrease in adipocytes turnover leading to insulin resistance.

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 Evidence for the Regulatory Role of Lipocalin 2 in High-Fat Diet-Induced Adipose Tissue Remodeling in Male Mice

Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3525-3538 ◽  
Author(s):  
Hong Guo ◽  
Merlijn Bazuine ◽  
Daozhong Jin ◽  
Merry M. Huang ◽  
Samuel W. Cushman ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
High Fat Diet ◽  
Adipocyte Differentiation ◽  
Tissue Remodeling ◽  
Peroxisome Proliferator ◽  
Lipocalin 2 ◽  
Peroxisome Proliferator Activated Receptor ◽  
Adipose Tissue Remodeling ◽  
Fat Depot

Lipocalin 2 (Lcn2) has previously been characterized as an adipokine/cytokine playing a role in glucose and lipid homeostasis. In this study, we investigate the role of Lcn2 in adipose tissue remodeling during high-fat diet (HFD)-induced obesity. We find that Lcn2 protein is highly abundant selectively in inguinal adipose tissue. During 16 weeks of HFD feeding, the inguinal fat depot expanded continuously, whereas the expansion of the epididymal fat depot was reduced in both wild-type (WT) and Lcn2−/− mice. Interestingly, the depot-specific effect of HFD on fat mass was exacerbated and appeared more pronounced and faster in Lcn2−/− mice than in WT mice. In Lcn2−/− mice, adipocyte hypertrophy in both inguinal and epididymal adipose tissue was more profoundly induced by age and HFD when compared with WT mice. The expression of peroxisome proliferator-activated receptor-γ protein was significantly down-regulated, whereas the gene expression of extracellular matrix proteins was up-regulated selectively in epididymal adipocytes of Lcn2−/− mice. Consistent with these observations, collagen deposition was selectively higher in the epididymal, but not in the inguinal adipose depot of Lcn2−/− mice. Administration of the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (Rosi) restored adipogenic gene expression. However, Lcn2 deficiency did not alter the responsiveness of adipose tissue to Rosi effects on the extracellular matrix expression. Rosi treatment led to the further enlargement of adipocytes with improved metabolic activity in Lcn2−/− mice, which may be associated with a more pronounced effect of Rosi treatment in reducing TGF-β in Lcn2−/− adipose tissue. Consistent with these in vivo observations, Lcn2 deficiency reduces the adipocyte differentiation capacity of stromal-vascular cells isolated from HFD-fed mice in these cells. Herein Rosi treatment was again able to stimulate adipocyte differentiation to a similar extent in WT and Lcn2−/− inguinal and epididymal stromal-vascular cells. Thus, combined, our data indicate that Lcn2 has a depot-specific role in HFD-induced adipose tissue remodeling.

Sirtuin 1 is involved in oleic acid-induced calf hepatocyte steatosis via alterations in lipid metabolism-related proteins

2021 ◽  
Vol 99 (10) ◽  
Author(s):  
Hongyan Ding ◽  
Yu Li ◽  
Leihong Liu ◽  
Ning Hao ◽  
Suping Zou ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Mrna Abundance ◽  
Sirtuin 1 ◽  
Peroxisome Proliferator ◽  
Acetyl Coa Carboxylase ◽  
Peroxisome Proliferator Activated Receptor ◽  
Lower Protein ◽  
Tag Accumulation

Abstract Sirtuin 1 (SIRT1), an NAD-dependent protein deacetylase, plays a central role in the control of lipid metabolism in nonruminants. However, the role of SIRT1 in hepatic lipid metabolism in dairy cows with fatty liver is not well known. Thus, we used isolated primary bovine hepatocytes to determine the role of SIRT1 in protecting cells against oleic acid (OA)-induced steatosis. Recombinant adenoviruses to overexpress (AD-GFP-SIRT1-E) or knockdown (AD-GFP-SIRT1-N) SIRT1 were used for transduction of hepatocytes. Calf hepatocytes isolated from five female calves (1 d old, 30 to 40 kg) were used to determine both time required and the lowest dose of OA that could induce triacylglycerol (TAG) accumulation. Analyses indicated that 0.25 mM OA for 24 h was suitable to induce TAG accumulation. In addition, OA not only led to an increase in TAG, but also upregulated mRNA and protein abundance of sterol regulatory element-binding transcription factor 1 (SREBF1) and downregulated SIRT1 and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PPARGC1A). Thus, these in vitro conditions were deemed optimal for subsequent experiments. Calf hepatocytes were cultured and incubated with OA (0.25 mM) for 24 h, followed by adenoviral AD-GFP-SIRT1-E or AD-GFP-SIRT1-N transduction for 48 h. Overexpression of SIRT1 led to greater protein and mRNA abundance of SIRT1 along with fatty acid oxidation-related genes including PPARGC1A, peroxisome proliferator-activated receptor alpha (PPARA), retinoid X receptor α (RXRA), and ratio of phospho-acetyl-CoA carboxylase alpha (p-ACACA)/total acetyl-CoA carboxylase alpha (ACACA). In contrast, it resulted in lower protein and mRNA abundance of genes related to lipid synthesis including SREBF1, fatty acid synthase (FASN), apolipoprotein E (APOE), and low-density lipoprotein receptor (LDLR). The concentration of TAG decreased due to SIRT1 overexpression. In contrast, silencing SIRT1 led to lower protein and mRNA abundance of SIRT1, PPARGC1A, PPARA, RXRA, and greater protein and mRNA abundance of SREBF1, FASN, APOE, and LDLR. Further, those responses were accompanied by greater content of cellular TAG and total cholesterol (TC). Overall, data from these in vitro studies indicated that SIRT1 is involved in the regulation of lipid metabolism in calf hepatocytes subjected to an increase in the supply of OA. Thus, it is possible that alterations in SIRT1 abundance and activity in vivo contribute to development of fatty liver in dairy cows.

scholarly journals Non-Viable Lactobacillus johnsonii JNU3402 Protects against Diet-Induced Obesity

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1494
Author(s):  
Garam Yang ◽  
Eunjeong Hong ◽  
Sejong Oh ◽  
Eungseok Kim
Keyword(s):  
Adipose Tissue ◽  
Body Weight Gain ◽  
Normal Diet ◽  
The Body ◽  
Peroxisome Proliferator ◽  
Lactobacillus Johnsonii ◽  
Peroxisome Proliferator Activated Receptor ◽  
Diet Induced Obesity ◽  
Brown Adipose ◽  
And Function

In this study, the role of non-viable Lactobacillus johnsonii JNU3402 (NV-LJ3402) in diet-induced obesity was investigated in mice fed a high-fat diet (HFD). To determine whether NV-LJ3402 exhibits a protective effect against diet-induced obesity, 7-week-old male C57BL/6J mice were fed a normal diet, an HFD, or an HFD with NV-LJ3402 for 14 weeks. NV-LJ3402 administration was associated with a significant reduction in body weight gain and in liver, epididymal, and inguinal white adipose tissue (WAT) and brown adipose tissue weight in HFD-fed mice. Concomitantly, NV-LJ3402 administration to HFD-fed mice also decreased the triglyceride levels in the plasma and metabolic tissues and slightly improved insulin resistance. Furthermore, NV-LJ3402 enhanced gene programming for energy dissipation in the WATs of HFD-fed mice as well as in 3T3-L1 adipocytes with increased peroxisome proliferator-activated receptor-γ (PPARγ) transcriptional activity, suggesting that the PPARγ pathway plays a key role in mediating the anti-obesity effect of NV-LJ3402 in HFD-fed mice. Furthermore, NV-LJ3402 administration in HFD-fed mice enhanced mitochondrial levels and function in WATs and also increased the body temperature upon cold exposure. Together, these results suggest that NV-LJ3402 could be safely used to develop dairy products that ameliorate diet-induced obesity and hyperlipidemia.

scholarly journals Apple Flavonols Mitigate Adipocyte Inflammation and Promote Angiogenic Factors in LPS- and Cobalt Chloride-Stimulated Adipocytes, in Part by a Peroxisome Proliferator-Activated Receptor-γ-Dependent Mechanism

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1386 ◽  
Author(s):  
Danyelle M. Liddle ◽  
Meaghan E. Kavanagh ◽  
Amanda J. Wright ◽  
Lindsay E. Robinson
Keyword(s):  
Mrna Expression ◽  
Cobalt Chloride ◽  
Nuclear Factor Κb ◽  
Diglycidyl Ether ◽  
Low Grade ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Anti Inflammatory

Adipose tissue (AT) expansion induces local hypoxia, a key contributor to the chronic low-grade inflammation that drives obesity-associated disease. Apple flavonols phloretin (PT) and phlorizin (PZ) are suggested anti-inflammatory molecules but their effectiveness in obese AT is inadequately understood. Using in vitro models designed to reproduce the obese AT microenvironment, 3T3-L1 adipocytes were cultured for 24 h with PT or PZ (100 μM) concurrent with the inflammatory stimulus lipopolysaccharide (LPS; 10 ng/mL) and/or the hypoxia mimetic cobalt chloride (CoCl2; 100 μM). Within each condition, PT was more potent than PZ and its effects were partially mediated by peroxisome proliferator-activated receptor (PPAR)-γ (p < 0.05), as tested using the PPAR-γ antagonist bisphenol A diglycidyl ether (BADGE). In LPS-, CoCl2-, or LPS + CoCl2-stimulated adipocytes, PT reduced mRNA expression and/or secreted protein levels of inflammatory and macrophage chemotactic adipokines, and increased that of anti-inflammatory and angiogenic adipokines, which was consistent with reduced mRNA expression of M1 polarization markers and increased M2 markers in RAW 264.7 macrophages cultured in media collected from LPS + CoCl2-simulated adipocytes (p < 0.05). Further, within LPS + CoCl2-stimulated adipocytes, PT reduced reactive oxygen species accumulation, nuclear factor-κB activation, and apoptotic protein expression (p < 0.05). Overall, apple flavonols attenuate critical aspects of the obese AT phenotype.

scholarly journals The endocrine disruptor mono-(2-ethylhexyl)phthalate promotes adipocyte differentiation and induces obesity in mice

2012 ◽  
Vol 32 (6) ◽  
pp. 619-629 ◽  
Author(s):  
Chanjuan Hao ◽  
Xuejia Cheng ◽  
Hongfei Xia ◽  
Xu Ma
Keyword(s):  
Target Genes ◽  
Adipocyte Differentiation ◽  
Cell Model ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Glucose Levels ◽  
Ethylhexyl Phthalate

The environmental obesogen hypothesis proposes that exposure to endocrine disruptors during developmental ‘window’ contributes to adipogenesis and the development of obesity. MEHP [mono-(2-ethylhexyl) phthalate], a metabolite of the widespread plasticizer DEHP [di-(2-ethylhexyl) phthalate], has been found in exposed organisms and identified as a selective PPARγ (peroxisome-proliferator-activated receptor γ) modulator. However, implication of MEHP on adipose tissue development has been poorly investigated. In the present study, we show the dose-dependent effects of MEHP on adipocyte differentiation and GPDH (glycerol-3-phosphate dehydrogenase) activity in the murine 3T3-L1 cell model. MEHP induced the expression of PPARγ as well as its target genes required for adipogenesis in vitro. Moreover, MEHP perturbed key regulators of adipogenesis and lipogenic pathway in vivo. In utero exposure to a low dose of MEHP significantly increased b.w. (body weight) and fat pad weight in male offspring at PND (postnatal day) 60. In addition, serum cholesterol, TAG (triacylglycerol) and glucose levels were also significantly elevated. These results suggest that perinatal exposure to MEHP may be expected to increase the incidence of obesity in a sex-dependent manner and can act as a potential chemical stressor for obesity and obesity-related disorders.

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 SREBP-1c/MicroRNA 33b Genomic Loci Control Adipocyte Differentiation

2016 ◽  
Vol 36 (7) ◽  
pp. 1180-1193 ◽  
Author(s):  
Nathan L. Price ◽  
Brandon Holtrup ◽  
Stephanie L. Kwei ◽  
Martin Wabitsch ◽  
Matthew Rodeheffer ◽  
...  
Keyword(s):  
Lipid Droplet ◽  
Target Genes ◽  
Adipocyte Differentiation ◽  
Regulatory Element ◽  
Critical Role ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
The Impact

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promotingin vitroadipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precludingin vivoassessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along withSREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.

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