Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8477151 | Molecular and Cellular Endocrinology | 2014 | 10 Pages |
Abstract
Long-term treatment with glucocorticoids (GCs) or dysregulation of endogenous GC levels induces a series of metabolic diseases, such as insulin resistance, obesity and type 2 diabetes. We previously showed that MAP kinase phosphatase-3 (MKP-3) plays an important role in glucose metabolism. The aim of this study is to investigate the role of MKP-3 in GC-induced metabolic disorders. Dexamethasone (Dex), a synthetic GC, increases MKP-3 protein expression both in cultured hepatoma cells and in the liver of lean mice. This effect is likely mediated by forkhead box protein O1 (FOXO1) because disruption of endogenous FOXO1 function by either interfering RNA mediated FOXO1 knockdown or overexpression of a dominant negative FOXO1 mutant blocks Dex-induced upregulation of MKP-3 protein. In addition, overexpression of FOXO1 is sufficient to induce MKP-3 protein expression. MKP-3 deficient mice are protected from several side effects of chronic Dex exposure, such as body weight gain, adipose tissue enlargement, hepatic lipid accumulation, and insulin resistance. The beneficial phenotypes in mice lacking MKP-3 are largely attributed to the absence of MKP-3 in the liver since only hepatic insulin signaling has been preserved among the three insulin target tissues (liver, muscle and adipose tissue).
Keywords
ERKVLDLACC1DIO miceSCD1ACC2acetyl-CoA carboxylase 2PPARγFOXO1mTORFASMKP-3Dusp6DEXPI3KMAPKStearoyl-coenzyme A desaturase 1acetyl-CoA carboxylase 1fatty acid synthasetriglycerideDexamethasonephosphoinositide 3-kinasevery low-density lipoproteinLipogenesisObesityInsulin resistanceDiet-induced obese micewild typemammalian target of rapamycinHepatosteatosisForkhead box protein O1mitogen-activated protein kinaseextracellular signal-regulated kinasePeroxisome proliferator-activated receptor gammaGlucocorticoid
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Authors
Bin Feng, Qin He, Haiyan Xu,