Deleted in breast cancer 1 plays a functional role in adipocyte differentiation

2015 ◽  
Vol 308 (7) ◽  
pp. E554-E561 ◽  
Author(s):  
José María Moreno-Navarrete ◽  
María Moreno ◽  
Marta Vidal ◽  
Francisco Ortega ◽  
Marta Serrano ◽  
...  

Genetic deletion of Dbc1 in mice reduced adipose tissue senescence and inflammation while promoting an expansion of this tissue. Here, we aimed to investigate DBC1 mRNA and protein levels in human adipose tissue from subjects with a wide spectrum of fat mass ( cohort 1; n = 105) and insulin resistance ( cohort 2; n = 47); we also investigated the effects of DBC1 knockdown on 3T3-L1 adipocyte differentiation. DBC1 mRNA was relatively abundant in both visceral (VAT) and subcutaneous adipose tissue (SAT) (mainly in the adipocyte fraction), being decreased in adipose tissue from obese compared with lean subjects. In both VAT and SAT, DBC1 mRNA levels were negatively associated with BMI and positively associated with age and the expression of PPARγ, GLUT4, IRS1, lipogenic ( FASN, ACACA), lipid droplet-associated genes ( PLIN1, FSP27, ADRP, and TIP47), and lipolytic ( ABDH5, AKAP, and PRKACA) genes but negatively associated with ADIPOQ in VAT. DBC1 mRNA and protein levels were increased in the early stages of adipocyte differentiation of human and 3T3-L1 adipocytes. Dbc1 knockdown (KD) with lentivirus led to enhanced adipocyte differentiation, increasing intracellular lipid accumulation and adipogenic gene expression. In conclusion, although DBC1 gene expression was reduced in adipose tissue from obese subjects, it was negatively associated with ADIPOQ gene expression in VAT, suggesting that DBC1 might promote visceral adipose tissue dysfunction. In vitro data supported the antiadipogenic effects of DBC1.

Diabetologia ◽  
2021 ◽  
Author(s):  
Juliana de Almeida-Faria ◽  
Daniella E. Duque-Guimarães ◽  
Thomas P. Ong ◽  
Lucas C. Pantaleão ◽  
Asha A. Carpenter ◽  
...  

Abstract Aims/hypothesis Levels of the microRNA (miRNA) miR-126-3p are programmed cell-autonomously in visceral adipose tissue of adult offspring born to obese female C57BL/6J mice. The spectrum of miR-126-3p targets and thus the consequences of its dysregulation for adipocyte metabolism are unknown. Therefore, the aim of the current study was to identify novel targets of miR-126-3p in vitro and then establish the outcomes of their dysregulation on adipocyte metabolism in vivo using a well-established maternal obesity mouse model. Methods miR-126-3p overexpression in 3T3-L1 pre-adipocytes followed by pulsed stable isotope labelling by amino acids in culture (pSILAC) was performed to identify novel targets of the miRNA. Well-established bioinformatics algorithms and luciferase assays were then employed to confirm those that were direct targets of miR-126-3p. Selected knockdown experiments were performed in vitro to define the consequences of target dysregulation. Quantitative real-time PCR, immunoblotting, histology, euglycaemic–hyperinsulinaemic clamps and glucose tolerance tests were performed to determine the phenotypic and functional outcomes of maternal programmed miR-126-3p levels in offspring adipose tissue. Results The proteomic approach confirmed the identity of known targets of miR-126-3p (including IRS-1) and identified Lunapark, an endoplasmic reticulum (ER) protein, as a novel one. We confirmed by luciferase assay that Lunapark was a direct target of miR-126-3p. Overexpression of miR-126-3p in vitro led to a reduction in Lunapark protein levels and increased Perk (also known as Eif2ak3) mRNA levels and small interference-RNA mediated knockdown of Lunapark led to increased Xbp1, spliced Xbp1, Chop (also known as Ddit3) and Perk mRNA levels and an ER stress transcriptional response in 3T3-L1 pre-adipocytes. Consistent with the results found in vitro, increased miR-126-3p expression in adipose tissue from adult mouse offspring born to obese dams was accompanied by decreased Lunapark and IRS-1 protein levels and increased markers of ER stress. At the whole-body level the animals displayed glucose intolerance. Conclusions/interpretation Concurrently targeting IRS-1 and Lunapark, a nutritionally programmed increase in miR-126-3p causes adipose tissue insulin resistance and an ER stress response, both of which may contribute to impaired glucose tolerance. These findings provide a novel mechanism by which obesity during pregnancy leads to increased risk of type 2 diabetes in the offspring and therefore identify miR-126-3p as a potential therapeutic target. Graphical abstract


Endocrinology ◽  
2003 ◽  
Vol 144 (12) ◽  
pp. 5578-5584 ◽  
Author(s):  
Philippe Linscheid ◽  
Dalma Seboek ◽  
Eric S. Nylen ◽  
Igor Langer ◽  
Mirjam Schlatter ◽  
...  

2008 ◽  
Vol 93 (5) ◽  
pp. 1995-2001 ◽  
Author(s):  
Sergey Krapivner ◽  
Sergej Popov ◽  
Ekaterina Chernogubova ◽  
Mai-Lis Hellénius ◽  
Rachel M. Fisher ◽  
...  

Abstract Background: Insulin-induced genes (INSIGs) encode proteins that block proteolytic activation of sterol regulatory element-binding proteins, transcription factors that regulate lipogenic enzymes, and adipocyte differentiation. Objective: Here, we analyzed the relative significance of INSIG1 and INSIG2 in human liver and adipocyte metabolism, and defined a novel, functional polymorphism in the promoter of INSIG2 associated with body mass index. Research Methods: Variations in gene expression of different human tissues, of hepatoma cells exposed to INSIG1 and INSIG2 gene silencing probes, and of differentiating 3T3-L1 adipocytes were determined by real-time quantitative PCR. The functional significance of a novel polymorphism in the promoter of INSIG2 was analyzed using in vitro methods and gene expression analysis of human adipose tissue, whereas the phenotype associated with this polymorphism was studied in two cohorts of middle-aged men. Results: Gene expression analysis of 17 human tissues demonstrated that INSIG1 is highly expressed in the liver, whereas INSIG2 is ubiquitously expressed. Gene silencing experiments confirmed that INSIG1, but not INSIG2, regulates the expression of sterol regulatory element-binding proteins target genes in human hepatoma cells. In contrast, adipocyte differentiation of 3T3-L1 cells was associated with a 13-fold increase in expression of INSIG2. Significant relationships between the INSIG2–102G/A polymorphism and body mass index were observed in two cohorts of middle-aged men (ANOVA P = 0.017 and 0.044, respectively). In vitro studies and analysis of allele-specific expression in human adipose tissue substantiated the functional significance of the INSIG2–102G/A polymorphism. Conclusion: INSIG2 is involved in adipocyte metabolism and body weight regulation.


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Anny Waloski Robert ◽  
Addeli Bez Batti Angulski ◽  
Lucia Spangenberg ◽  
Patrícia Shigunov ◽  
Isabela Tiemy Pereira ◽  
...  

2020 ◽  
Author(s):  
Shan Cao ◽  
Lan Xiao ◽  
Junyao Wang ◽  
Guodong Chen ◽  
Yulan Liu

The integrity of the intestinal mucosal barrier protects hosts against pathological conditions. Early mucosal restitution after wounding refers to epithelial cell migration into a defect. The RNA-binding protein HuR plays an important role in the posttranscriptional regulation of gene expression and is involved in many aspects of cellular physiology. In the present study, we investigated the role of HuR in the regulation of cell migration through the posttranscriptional regulation of Caveolin-1 (Cav-1). Online software was used to identify Cav-1 mRNA as a potential target of HuR. The interaction of HuR with Cav-1 mRNA was investigated via ribonucleoprotein immunoprecipitation (RNP IP) assays and biotin pulldown analysis. HuR was found to bind specifically to the Cav-1 3’-UTR rather than the coding region or 5’-UTR. Transfection of cells with siHuR decreased both HuR protein levels and Cav-1 protein levels; conversely, ectopic overexpression of HuR via infection of cells with an adenoviral vector containing HuR cDNA (AdHuR) increased Cav-1 protein levels without disturbing Cav-1 mRNA levels. Thus, HuR enhanced Cav-1 expression in vitro by stimulating Cav-1 translation. Intestinal epithelium–specific HuR knockout in mice decreased Cav-1 protein levels without changing Cav-1 mRNA levels, consistent with the in vitro results. Decreasing the levels of HuR via siHuR transfection inhibited early epithelial repair, but this effect was reversed by ectopic overexpression of GFP-tagged Cav-1. These results indicate that posttranscriptional regulation of Cav-1 gene expression by HuR plays a critical role in the regulation of rapid epithelial repair after wounding.


2005 ◽  
Vol 288 (4) ◽  
pp. E798-E804 ◽  
Author(s):  
Matthew R. Ricci ◽  
Mi-Jeong Lee ◽  
Colleen D. Russell ◽  
Yanxin Wang ◽  
Sean Sullivan ◽  
...  

In vivo and in vitro studies indicate that β-adrenergic receptor agonists decrease leptin release from fat cells in as little as 30 min. Our objective was to determine whether alterations in leptin biosynthesis or secretion were involved in the short-term adrenergic regulation of leptin in human and rat adipose tissue. Isoproterenol (Iso) decreased leptin release from incubated adipose tissue of both nonobese and obese subjects to similar extent (−28 vs. −21% after 3 h). Inhibition of protein synthesis with cycloheximide did not block the effect of Iso on leptin release from human adipose tissue, suggesting that the Iso effect is independent of leptin synthesis. Iso also tended to increase tissue leptin content at the end of the 3-h incubation, as expected from the observed inhibition of release. Consistent with a posttranslational mechanism, Iso treatment did not affect leptin mRNA levels or relative rate of leptin biosynthesis as directly assessed by [35S]methionine incorporation into immunoprecipitable leptin. In contrast to these results in human adipose tissues, Iso did not decrease basal leptin release from rat adipose tissue. However, Iso did decrease insulin-stimulated leptin release by inhibiting the ability of insulin to increase leptin biosynthesis without detectably affecting leptin mRNA levels. Thus, in both human and rat, adrenergic regulation of posttranscriptional events (secretion in humans, translation in rats) may contribute to the rapid decline in circulating leptin that occurs when the sympathetic nervous system is activated, such as during fasting and cold exposure. Furthermore, the rat does not provide an ideal model to study mechanisms of cellular leptin regulation in humans.


2011 ◽  
Vol 301 (6) ◽  
pp. E1254-E1261 ◽  
Author(s):  
O. Osorio-Conles ◽  
M. Guitart ◽  
M. R. Chacón ◽  
E. Maymo-Masip ◽  
J. M. Moreno-Navarrete ◽  
...  

Plasma acutephase protein pentraxin 3 (PTX3) concentration is dysregulated in human obesity and metabolic syndrome. Here, we explore its relationship with insulin secretion and sensitivity, obesity markers, and adipose tissue PTX3 gene expression. Plasma PTX3 protein levels were analyzed in a cohort composed of 27 lean [body mass index (BMI) ≤25 kg/m2] and 48 overweight (BMI 25–30 kg/m2) men ( cohort 1). In this cohort, plasma PTX3 was negatively correlated with fasting triglyceride levels and insulin secretion after intravenous and oral glucose administration. Plasma PTX3 protein and PTX3 gene expression in visceral (VAT) and subcutaneous (SAT) whole adipose tissue and adipocyte and stromovascular fractions were analyzed in cohort 2, which was composed of 19 lean, 28 overweight, and 15 obese subjects (BMI >30 kg/m2). An inverse association with body weight and waist/hip ratio was observed in cohort 2. In VAT depots, PTX3 mRNA levels were higher in subjects with BMI >25 kg/m2than in lean subjects, positively correlated with IL-1β mRNA levels, and higher in the adipocyte than stromovascular fraction. Human preadipocyte SGBS cell line was used to study PTX3 production in response to factors that obesity entails. In SGBS adipocytes, PTX3 gene expression was enhanced by IL-1β and TNFα but not IL-6 or insulin. In conclusion, the negative correlation between PTX3 and glucose-stimulated insulin secretion suggests a role for PTX3 in metabolic control. PTX3 gene expression is upregulated in VAT depots in obesity, despite lower plasma PTX3 protein, and by some proinflammatory cytokines in cultured adipocytes.


Endocrine ◽  
2002 ◽  
Vol 18 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Florence Machinal-Quélin ◽  
Marie-Noëlle Dieudonné ◽  
René Pecquery ◽  
Marie-Christine Leneveu ◽  
Yves Giudicelli

1989 ◽  
Vol 256 (2) ◽  
pp. C448-C451 ◽  
Author(s):  
J. A. Saye ◽  
L. A. Cassis ◽  
T. W. Sturgill ◽  
K. R. Lynch ◽  
M. J. Peach

It has previously been established that angiotensinogen mRNA is present in brown and white adipose tissue of the rat. To determine whether angiotensinogen gene expression is present in adipocytes as compared with other cell elements, we have examined angiotensinogen mRNA in 3T3-L1 cells. These cells undergo adipocyte differentiation when the culture reaches confluence. To accelerate the differentiation process, cells were treated with dexamethasone and isobutylmethylxanthine for 3 days. On the 7th day after drug treatment, RNA was extracted from cells and was examined for angiotensinogen mRNA using a full-length rat angiotensinogen cDNA. Angiotensinogen mRNA was readily detected in differentiated 3T3-L1 cells. To determine when the gene is expressed, a 7-day time course from day 0 (before drug treatment) to day 7 was examined for the presence of angiotensinogen mRNA. In addition, C2 cells, a clonal cell line that does not differentiate into adipocytes, were examined. Angiotensinogen mRNA was detected on days 2-7 after drug treatment in 3T3-L1 cells, with no detectable levels in untreated 3T3-C2 cells. When 3T3-C2 cells were subjected to the same drug regimen, angiotensinogen mRNA levels increased in the same time course as 3T3-L1 cells. However, the increase in angiotensinogen message was greater in differentiating 3T3-L1 cells than in the nondifferentiating 3T3-C2 cells. Thus angiotensinogen mRNA is present in both adipocytes and in fibroblast-like cells and appears to be regulated by steroids.


2007 ◽  
Vol 92 (4) ◽  
pp. 1555-1559 ◽  
Author(s):  
Patrik Löfgren ◽  
Eva Sjölin ◽  
Kerstin Wåhlen ◽  
Johan Hoffstedt

Abstract Context: The cannabinoid receptor 1 gene (CNR1) is implicated in adipocyte function. Objective: We investigated human adipose tissue CNR1 mRNA in relation to obesity, clinical and metabolic variables, adipocyte function, and adiponectin (ADIPOQ) levels. Methods: We assessed sc fat biopsies from 96 obese and nonobese subjects and omental fat biopsies from 82 obese and nonobese subjects. Results: The sc and omental adipose CNR1 gene expression were similar in obese and nonobese subjects. No association between either sc or omental adipose CNR1 mRNA levels and body mass index, waist circumference, plasma levels of glucose and insulin, lipids, or blood pressure was found. The sc and omental maximal adrenergic lipolytic activation as well as lipolytic adrenoceptor sensitivity were not related to CNR1 gene expression. Lipogenesis in sc adipocytes also showed no association with CNR1 mRNA levels. Finally, no relation was found between adipose CNR1 gene expression and ADIPOQ mRNA, adipose tissue adiponectin secretion, or circulating adiponectin. Conclusion: We found no association of human adipose tissue CNR1 mRNA expression with measures of body fat, metabolic parameters, fat cell function, or ADIPOQ expression. These data do not suggest a major role of human adipose CNR1 in fat cell function or metabolic disease development.


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