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Type: Artigo de periódico
Title: Exercise Training Decreases Mitogen-activated Protein Kinase Phosphatase-3 Expression And Suppresses Hepatic Gluconeogenesis In Obese Mice.
Author: Souza Pauli, Luciana Santos
Ropelle, Eloize Cristina Chiarreotto
de Souza, Claudio Teodoro
Cintra, Dennys Esper
da Silva, Adelino Sanchez Ramos
de Almeida Rodrigues, Bárbara
de Moura, Leandro Pereira
Marinho, Rodolfo
de Oliveira, Vanessa
Katashima, Carlos Kiyoshi
Pauli, José Rodrigo
Ropelle, Eduardo Rochete
Abstract: Insulin plays an important role in the control of hepatic glucose production. Insulin resistant states are commonly associated with excessive hepatic glucose production, which contributes to both fasting hyperglycaemia and exaggerated postprandial hyperglycaemia. In this regard, increased activity of phosphatases may contribute to the dysregulation of gluconeogenesis. Mitogen-activated protein kinase phosphatase-3 (MKP-3) is a key protein involved in the control of gluconeogenesis. MKP-3-mediated dephosphorylation activates FoxO1 (a member of the forkhead family of transcription factors) and subsequently promotes its nuclear translocation and binding to the promoters of gluconeogenic genes such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). In this study, we investigated the effects of exercise training on the expression of MKP-3 and its interaction with FoxO1 in the livers of obese animals. We found that exercised obese mice had a lower expression of MKP-3 and FoxO1/MKP-3 association in the liver. Further, the exercise training decreased FoxO1 phosphorylation and protein levels of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and gluconeogenic enzymes (PEPCK and G6Pase). These molecular results were accompanied by physiological changes, including increased insulin sensitivity and reduced hyperglycaemia, which were not caused by reductions in total body mass. Similar results were also observed with oligonucleotide antisense (ASO) treatment. However, our results showed that only exercise training could reduce an obesity-induced increase in HNF-4α protein levels while ASO treatment alone had no effect. These findings could explain, at least in part, why additive effects of exercise training treatment and ASO treatment were not observed. Finally, the suppressive effects of exercise training on MKP-3 protein levels appear to be related, at least in part, to the reduced phosphorylation of Extracellular signal-regulated kinases (ERK) in the livers of obese mice.
Subject: Animals
Diet, High-fat
Dual Specificity Phosphatase 6
Forkhead Transcription Factors
Hepatocyte Nuclear Factor 4
Insulin Resistance
Map Kinase Signaling System
Oligodeoxyribonucleotides, Antisense
Physical Conditioning, Animal
Transcription Factors
Citation: The Journal Of Physiology. v. 592, n. Pt 6, p. 1325-40, 2014-Mar.
Rights: fechado
Identifier DOI: 10.1113/jphysiol.2013.264002
Date Issue: 2014
Appears in Collections:Unicamp - Artigos e Outros Documentos

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