scholarly journals Transcription Suppression of Peroxisome Proliferator-Activated Receptor γ2 Gene Expression by Tumor Necrosis Factor α via an Inhibition of CCAAT/ Enhancer-binding Protein δ during the Early Stage of Adipocyte Differentiation

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 4948-4956 ◽  
Author(s):  
Masataka Kudo ◽  
Akira Sugawara ◽  
Akira Uruno ◽  
Kazuhisa Takeuchi ◽  
Sadayoshi Ito

Abstract TNFα is known to inhibit adipocyte differentiation and induce insulin resistance. Moreover, TNFα is known to down-regulate peroxisome proliferator-activated receptor (PPAR)γ2, an adipocyte-specific nuclear receptor of insulin-sensitizer thiazolidinediones. To clarify molecular mechanisms of TNFα- mediated PPARγ2 down-regulation, we here examined the effect of TNFα on transcription regulation of PPARγ2 gene expression during the early stage of adipocyte differentiation. 3T3-L1 preadipocytes (2 d after 100% confluent) were incubated in a differentiation mixture (dexamethasone, insulin, 3-isobutyl-1-methlxanthine), with or without 50 ng/ml TNFα, for 24 h. TNFα significantly decreased PPARγ2 expression both at mRNA and protein levels (to ∼40%), as well as aP2 mRNA expression. The mouse PPARγ2 gene promoter region (2.2-kb) was isolated and was used for luciferase reporter assays by transient transfection. TNFα significantly suppressed PPARγ2 gene transcription (to ∼50%), and deletion analyses demonstrated that the suppression was mediated via CCAAT/enhancer-binding protein (C/EBP) binding elements at the −320/−340 region of the promoter. Moreover, TNFα significantly decreased expression of C/EBPδ mRNA and protein levels (to ∼40%). EMSA, using 3T3-L1 cells nuclear extracts with the −320/−340 region as a probe, demonstrated the binding of C/EBPδ to the element, which was significantly decreased by TNFα treatment. Overexpression of CEBP/δ prevented the TNFα-mediated suppression of PPARγ2 transactivation. Taken together, TNFα suppresses PPARγ2 gene transcription by the inhibition of C/EBPδ expression and its DNA binding during the early stage of adipocyte differentiation, which may contribute to the inhibition of adipocyte differentiation, as well as the induction of insulin resistance.

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 758
Author(s):  
Hee Yang ◽  
Min Jeong Kang ◽  
Gihyun Hur ◽  
Tae Kyung Lee ◽  
In Sil Park ◽  
...  

Adipocyte differentiation (adipogenesis) is a crucial process that determines the total number and size of mature adipocytes that will develop. In this study, the anti-adipogenic effect of sulforaphene (SFEN), a dietary isothiocyanate (ITC) derived from radish, is investigated both in 3T3-L1 pre-adipocytes and in human adipose tissue-derived stem cells. The results revealed that SFEN significantly inhibit adipogenic cocktail-induced adipocyte differentiation and lipid accumulation at the early stage of adipogenesis. Additionally, the effects are more potent compared to those of other ITCs derived from various cruciferous vegetables. As a related molecular mechanism of action, SFEN promotes the post-translational degradation of CCAAT/enhancer-binding protein (C/EBP) β by decreasing the stability of C/EBPβ, which is responsible for decreasing the expression of master regulatory proteins such as peroxisome proliferator-activated receptor γ and C/EBPα. Collectively, these results suggest that the intake of SFEN-enriched natural materials could be helpful as a strategy for preventing obesity.


2013 ◽  
Vol 304 (11) ◽  
pp. C1091-C1097 ◽  
Author(s):  
Takeshi Honda ◽  
Aiko Ishii ◽  
Makoto Inui

PDZRN3, a member of the PDZRN (or LNX) family of proteins, is essential for the differentiation of mesenchymal stem cells into myotubes, but it plays an inhibitory role in the differentiation of these cells into osteoblasts. Given that mesenchymal stem cells also differentiate into adipocytes, we examined the possible role of PDZRN3 in adipogenesis in mouse 3T3-L1 preadipocytes. The expression of PDZRN3 decreased at both the mRNA and protein levels during adipogenic differentiation. RNAi-mediated depletion of PDZRN3 enhanced the differentiation of 3T3-L1 cells into adipocytes as assessed on the basis of lipid accumulation. The upregulation of aP2 and CCAAT/enhancer-binding protein (C/EBP)-β during adipocyte differentiation was also enhanced in the PDZRN3-depleted cells, as was the induction of peroxisome proliferator-activated receptor-γ (PPARγ), an upstream regulator of aP2 and C/EBPα, at both the mRNA and protein levels. Among transcription factors that control the expression of PPARγ, we found that STAT5b, but not STAT5a, was upregulated in PDZRN3-depleted cells at both mRNA and protein levels. Tyrosine phosphorylation of STAT5b, but not that of STAT5a, was also enhanced at an early stage of differentiation by PDZRN3 depletion. In addition, the expression of C/EBPβ during the induction of differentiation was enhanced at the mRNA and protein levels in PDZRN3-depleted cells. Our results thus suggest that PDZRN3 negatively regulates adipogenesis in 3T3-L1 cells through downregulation of STAT5b and C/EBPβ and consequent suppression of PPARγ expression.


Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2950 ◽  
Author(s):  
Quancai Sun ◽  
Jie Lin ◽  
Yukui Peng ◽  
Ruichang Gao ◽  
Ye Peng

Flubendiamide, a ryanoid class insecticide, is widely used in agriculture. Several insecticides have been reported to promote adipogenesis. However, the potential influence of flubendiamide on adipogenesis is largely unknown. The current study was therefore to determine the effects of flubendiamide on adipogenesis utilizing the 3T3-L1 adipocytes model. Flubendiamide treatment not only enhanced triglyceride content in 3T3-L1 adipocytes, but also increased the expression of cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT)/enhancer-binding protein α and peroxisome proliferator-activated receptor gamma-γ, two important regulators of adipocyte differentiation. Moreover, the expression of the most important regulator of lipogenesis, acetyl coenzyme A carboxylase, was also increased after flubendiamide treatment. Further study revealed that 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or A769662, two Adenosine 5′-monophosphate (AMP)-activated protein kinase α activators, subverted effects of flubendiamide on enhanced adipogenesis. Together, these results suggest that flubendiamide promotes adipogenesis via an AMPKα-mediated pathway.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sae-Rom Yoo ◽  
Chang-Seob Seo ◽  
Hyeun-Kyoo Shin ◽  
Soo-Jin Jeong

Background. Oyaksungi-san (OYSGS) is a herbal formula that has been used for treating cardiovascular diseases in traditional Asian medicine. Here, we investigated the antiadipogenic effect of OYSGS extract in 3T3-L1 adipose cells.Methods. 3T3-L1 preadipocytes were differentiated into adipocytes with or without OYSGS. After differentiation, we measured Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity, leptin production, mRNA, and protein levels of adipogenesis-related factors.Results. OYSGS extract dramatically inhibited intracellular lipid accumulation in the differentiated adipocytes. It also significantly suppressed the (GPDH) activity, triglyceride (TG) content, and leptin production by reducing the expression of adipogenesis-related genes including lipoprotein lipase, fatty acid binding protein 4, CCAAT/enhancer-binding protein-alpha (C/EBP-α), and peroxisome proliferator-activated receptor gamma (PPAR-γ). Furthermore, OYSGS clearly enhanced phosphorylation of AMP-activated protein kinase (AMPK) as well as its substrate acetyl CoA (ACC) carboxylase.Conclusions. Our results demonstrate that OYSGS negatively controls TG accumulation in 3T3-L1 adipocytes. We suggest antiadipogenic activity of OYSGS and its potential benefit in preventing obesity.


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