TET2 facilitates PPARγ agonist–mediated gene regulation and insulin sensitization in adipocytes
| Autor: | Anushka Paladugu, Sarah Fung, Sona Kang, Xiang Ma, Dongjoo You, Sneha Damal Villivalam, Fuyun Bian, Lauren Raquel Choy |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty Endocrinology Diabetes and Metabolism medicine.medical_treatment Diet High-Fat Polymerase Chain Reaction Dioxygenases Epigenesis Genetic Mice 03 medical and health sciences chemistry.chemical_compound Endocrinology Insulin resistance 3T3-L1 Cells Proto-Oncogene Proteins Adipocyte Internal medicine Adipocytes medicine Animals Regulation of gene expression biology Chemistry Insulin DNA Methylation medicine.disease DNA-Binding Proteins Mice Inbred C57BL PPAR gamma Insulin receptor Glucose 030104 developmental biology DNA demethylation Gene Expression Regulation DNA methylation biology.protein Demethylase Insulin Resistance Signal Transduction |
| Zdroj: | Metabolism. 89:39-47 |
| ISSN: | 0026-0495 |
| Popis: | Emerging evidence indicates that epigenetic mechanisms like DNA methylation directly contribute to metabolic regulation. For example, we previously demonstrated that de novo DNA methyltransferase Dnmt3a plays a causal role in the development of adipocyte insulin resistance. Recent studies suggest that DNA demethylation plays an important role in the developmental process of adipocytes. However, little is known about whether DNA demethylase ten-eleven translocation (TET) proteins regulate the metabolic functions of adipocytes. Methods The expression of Tet genes was assessed in the fractionated adipocytes of chow- and high fat diet–fed C57/Bl6 mice using qPCR and western blotting. The effect of Tet2 gain- or loss-of-function in fully mature 3T3-L1 adipocytes in the presence/absence of Rosiglitazone (Rosi) and TNF-α on insulin sensitivity was using the insulin-stimulated glucose uptake and insulin signaling assays. Gene expression and DNA methylation analyses of PPARγ target genes was performed in the same setting. In addition, PPARγ reporter assays, co-immunoprecipitation assays, PPARγ ChIP-PCR analyses were performed. Results We found that adipose expression of TET2, alone among its family members, was significantly reduced in diet-induced insulin resistance. TET2 gain-of-function was sufficient to promote insulin sensitivity while loss-of-function was necessary to facilitate insulin sensitization in response to the PPARγ agonist Rosiglitazone (Rosi) in cultured adipocytes. Consistent with this, TET2 was required for Rosi-dependent gene activation of certain PPARγ targets accompanied by changes in DNA demethylation at the promoter regions. Furthermore, TET2 was necessary to sustain PPARγ binding to target loci upon activation with Rosi via physical interaction with PPARγ. Conclusions Our data demonstrate that TET2 works as an epigenetic regulator of Rosi-mediated insulin sensitization and transcriptional regulation in adipocytes. |
| Databáze: | OpenAIRE |
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