scholarly journals Expression of Caveolin 1 Is Enhanced by DNA Demethylation during Adipocyte Differentiation. Status of Insulin Signaling

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e95100 ◽  
Author(s):  
Sara Palacios-Ortega ◽  
Maider Varela-Guruceaga ◽  
Fermín Ignacio Milagro ◽  
José Alfredo Martínez ◽  
Carlos de Miguel
Keyword(s):  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Dna Demethylation ◽  
Caveolin 1 ◽  
Differentiation Status

scholarly journals Effect of TNF-Alpha on Caveolin-1 Expression and Insulin Signaling During Adipocyte Differentiation and in Mature Adipocytes

2015 ◽  
Vol 36 (4) ◽  
pp. 1499-1516 ◽  
Author(s):  
Sara Palacios-Ortega ◽  
Maider Varela-Guruceaga ◽  
Miriam Algarabel ◽  
Fermín Ignacio Milagro ◽  
J. Alfredo Martínez ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Central Component ◽  
Low Grade ◽  
Caveolin 1 ◽  
Tnf Α ◽  
Uptake Assay ◽  
Factor Α ◽  
Low Grade Inflammation

Background/Aims: Tumor necrosis factor-α (TNF-α)-mediated chronic low-grade inflammation of adipose tissue is associated with obesity and insulin resistance. Caveolin-1 (Cav-1) is the central component of adipocyte caveolae and has an essential role in the regulation of insulin signaling. The effects of TNF-α on Cav-1 expression and insulin signaling during adipocyte differentiation and in mature adipocytes were studied. Methods: 3T3-L1 cells were differentiated (21 days) in the presence TNF-α (10 ng/mL) and mature adipocytes were also treated with TNF-α for 48 hours. Cav-1 and insulin receptor (IR) gene methylation were determined as well as Cav-1, IR, PKB/AKT-2 and Glut-4 expression and activation by real time RT-PCR and western blot. Baseline and insulin-induced glucose uptake was measured by the 2-[C14]-deoxyglucose uptake assay. Results: TNF-α slowed down the differentiation program, hindering the expression of some insulin signaling intermediates without fully eliminating insulin-mediated glucose uptake. In mature adipocytes, TNF-α did not compromise lipid-storage capacity, but downregulated the expression of the insulin signaling intermediates, totally blocking insulin-mediated glucose uptake. Insulin sensitivity correlated with the level of activated phospho-Cav-1 in both situations, strongly suggesting the direct contribution of Cav-1 to the maintenance of this physiological response. Conclusion: Cav-1 activation by phosphorylation seems to be essential for the maintenance of an active and insulin-sensitive glucose uptake.

scholarly journals A Synergistic Anti-Diabetic Effect by Ginsenosides Rb1 and Rg3 through Adipogenic and Insulin Signaling Pathways in 3T3-L1 Cells

2021 ◽  
Vol 11 (4) ◽  
pp. 1725
Author(s):  
Hee-Do Hong ◽  
Sun-Il Choi ◽  
Ok-Hwan Lee ◽  
Young-Cheul Kim
Keyword(s):  
Transcription Factors ◽  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Red Ginseng ◽  
Inhibitory Effects ◽  
Rt Pcr ◽  
High Concentration ◽  
Expression Of Genes ◽  
The Individual ◽  
Maximal Expression

Although ginsenosides Rb1 and Rg3 have been identified as the significant ginsenosides found in red ginseng that confer anti-diabetic actions, it is unclear whether insulin-sensitizing effects are mediated by the individual compounds or by their combination. To determine the effect of ginsenosides Rb1 and Rg3 on adipocyte differentiation, 3T3-L1 preadipocytes were induced to differentiate the standard hormonal inducers in the absence or presence of ginsenosides Rb1 or Rg3. Additionally, we determined the effects of Rb1, Rg3, or their combination on the expression of genes related to adipocyte differentiation, adipogenic transcription factors, and the insulin signaling pathway in 3T3-L1 cells using semi-quantitative RT-PCR. Rb1 significantly increased the expression of CEBPα, PPARγ, and aP2 mRNAs. However, Rg3 exerted its maximal stimulatory effect on these genes at 1 μM concentration, while a high concentration (50 μM) showed inhibitory effects. Similarly, treatment with Rb1 and Rg3 (1 μM) increased the expression of IRS-1, Akt, PI3K, GLUT4, and adiponectin. Importantly, co-treatment of Rb1 and Rg3 (9:1) induced the maximal expression levels of these mRNAs. Our data indicate that the anti-diabetic activity of red ginseng is, in part, mediated by synergistic actions of Rb1 and Rg3, further supporting the significance of minor Rg3.

Effects of ten–eleven translocation 1 (Tet1) on DNA methylation and gene expression in chicken primordial germ cells

2019 ◽  
Vol 31 (3) ◽  
pp. 509 ◽  
Author(s):  
Minli Yu ◽  
Dongfeng Li ◽  
Wanyan Cao ◽  
Xiaolu Chen ◽  
Wenxing Du
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Germ Cells ◽  
Dna Methyltransferase ◽  
Primordial Germ Cells ◽  
Dna Demethylation ◽  
Caveolin 1 ◽  
Expression Of Genes ◽  
Deleted In Azoospermia

Ten–eleven translocation 1 (Tet1) is involved in DNA demethylation in primordial germ cells (PGCs); however, the precise regulatory mechanism remains unclear. In the present study the dynamics of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in developing PGCs and the role of Tet1 in PGC demethylation were analysed. Results show that 5mC levels dropped significantly after embryonic Day 4 (E4) and 5hmC levels increased reaching a peak at E5–E5.5. Interestingly, TET1 protein was highly expressed during E5 to E5.5, which showed a consistent trend with 5hmC. The expression of pluripotency-associated genes (Nanog, PouV and SRY-box 2 (Sox2)) and germ cell-specific genes (caveolin 1 (Cav1), piwi-like RNA-mediated gene silencing 1 (Piwi1) and deleted in azoospermia-like (Dazl)) was upregulated after E5, whereas the expression of genes from the DNA methyltransferase family was decreased. Moreover, the Dazl gene was highly methylated in early PGCs and then gradually hypomethylated. Knockdown of Tet1 showed impaired survival and proliferation of PGCs, as well as increased 5mC levels and reduced 5hmC levels. Further analysis showed that knockdown of Tet1 led to elevated DNA methylation levels of Dazl and downregulated gene expression including Dazl. Thus, this study reveals the dynamic epigenetic reprogramming of chicken PGCs invivo and the molecular mechanism of Tet1 in regulating genomic DNA demethylation and hypomethylation of Dazl during PGC development.

scholarly journals Caveolin-1 Interacts with the Insulin Receptor and Can Differentially Modulate Insulin Signaling in Transfected Cos-7 Cells and Rat Adipose Cells

1999 ◽  
Vol 13 (12) ◽  
pp. 2013-2024 ◽  
Author(s):  
Fredrik H. Nystrom ◽  
Hui Chen ◽  
Li-Na Cong ◽  
Yunhua Li ◽  
Michael J. Quon
Keyword(s):  
Insulin Receptor ◽  
Insulin Signaling ◽  
Kinase Domain ◽  
Mitogen Activated Protein Kinase ◽  
Binding Motif ◽  
Intact Cells ◽  
Caveolin 1 ◽  
Mitogen Activated Protein ◽  
Adipose Cells

Abstract Caveolae may function as microdomains for signaling that help to determine specific biological actions mediated by the insulin receptor (IR). Caveolin-1, a major component of caveolae, contains a scaffolding domain (SD) that binds to a caveolin-1 binding motif in the kinase domain of the IR in vitro. To investigate the potential role of caveolin-1 in insulin signaling we overexpressed wild-type (Cav-WT) or mutant (Cav-Mut; F92A/V94A in SD) caveolin-1 in either Cos-7 cells cotransfected with IR or rat adipose cells (low and high levels of endogenous caveolin-1, respectively). Cav-WT coimmunoprecipitated with the IR to a much greater extent than Cav-Mut, suggesting that the SD is important for interactions between caveolin-1 and the IR in intact cells. We also constructed several IR mutants with a disrupted caveolin-1 binding motif and found that these mutants were poorly expressed and did not undergo autophosphorylation. Interestingly, overexpression of Cav-WT in Cos-7 cells significantly enhanced insulin-stimulated phosphorylation of Elk-1 (a mitogen-activated protein kinase-dependent pathway) while overexpression of Cav-Mut was without effect. In contrast, in adipose cells, overexpression of either Cav-WT or Cav-Mut did not affect insulin-stimulated phosphorylation of a cotransfected ERK2 (but did significantly inhibit basal phosphorylation of ERK2). Furthermore, we also observed a small inhibition of insulin-stimulated translocation of GLUT4 when either Cav-WT or Cav-Mut was overexpressed in adipose cells. Thus, interaction of caveolin-1 with IRs may differentially modulate insulin signaling to enhance insulin action in Cos-7 cells but inhibit insulin’s effects in adipose cells.

scholarly journals Effects of high glucose on caveolin-1 and insulin signaling in 3T3-L1 adipocytes

Adipocyte ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Sara Palacios-Ortega ◽  
Maider Varela-Guruceaga ◽  
J. Alfredo Martínez ◽  
Carlos de Miguel ◽  
Fermín I. Milagro
Keyword(s):  
Insulin Signaling ◽  
High Glucose ◽  
Caveolin 1

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

2011 ◽  
Vol 65 (3-4) ◽  
pp. 424-430 ◽  
Author(s):  
Sun-Sil Choi ◽  
Byung-Yoon Cha ◽  
Kagami Iida ◽  
Masako Sato ◽  
Young-Sil Lee ◽  
...  
Keyword(s):  
Insulin Signaling ◽  
Adipocyte Differentiation

scholarly journals Deletion of EHD2 Attenuated Adipocyte Hypertrophic Expansion and Ameliorated Diet-Induced Obesity and Insulin Resistance

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1633-1633
Author(s):  
Darius Fox ◽  
Ashley Toney ◽  
Mikyoung You ◽  
Hamid Band ◽  
Soonkyu Chung
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Insulin Sensitivity ◽  
Plasma Glucose ◽  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Adipocyte Size ◽  
Lipogenic Gene ◽  
Insulin Levels ◽  
Gene And Protein Expression

Abstract Objectives Obesity induces adipocyte hypertrophy, which promotes metabolic dysfunction. The EPS15-Homology Domain-Containing (EHD) 2 is an endocytic traffic-regulatory protein regulating caveolae stability, thereby participating cell size expansion. Although EHD2 is abundantly expressed in adipocytes, very little information is available on its role on adipose metabolism. This study aimed to define the role of EHD2 on governing adipocyte size, lipid metabolism and insulin sensitivity. Methods To prepare the EHD2-deficient adipocytes, primary ear mesenchymal stem cells were isolate from wildtype (WT) and EHD2 KO mice and induced differentiation into adipocytes. To induce obesity and insulin resistance, EHD2 KO and WT male mice were fed a high-fat diet (50% calorie from lard) for 8 weeks. The changes in body weight was monitored weekly. Fasting plasma glucose and insulin levels were determined by glucometer and ELISA respectively. Glucose tolerance test (GTT) was conducted after HF diet feeding. To investigate insulin signaling, human recombinant insulin (1 U/kg BW) was injected peritoneally and epididymal fat was collected immediately for measuring the phosphorylation levels of AKT (p-AKT), a downstream target for insulin. To determine the lipogenic gene and protein expression, qPCR and Western blot analysis were conducted. Results Deletion of EHD2 markedly upregulated EHD1 expression in primary adipocytes. Also, deletion of EHD2 significantly attenuated adipocyte differentiation and maintained smaller lipid droplets. Consistently, absence of EHD2 was linked with reduced lipogenic gene expression. In vivo study, EHD2 KO mice exhibited slightly lower total body weight, but fat mass was markedly reduced. After 8 weeks of HF diet, EHD2 KO mice had lower levels of plasma glucose and insulin levels compared with WT. EHD2 KO mice were more glucose tolerant during GTT. Insulin signaling study revealed that EHD2 KO mice showed higher levels of insulin-stimulated p-AKT compared to WT mice, indicating EHD2 deletion promotes insulin sensitivity. Conclusions This study suggests that EHD2 is required for maximal adipocyte differentiation and hypertrophic expansion. The absence of EHD2 was linked with improved insulin and glucose sensitivity, presumably due to reduced adiposity and adipocyte size. Funding Sources Nebraska EPSCoR (Food for Health 2017) Seed Grant.

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