Premium
High‐fat Diet Alters PP2A, TC10, and CIP4 Expression in Visceral Adipose Tissue of Rats
Author(s) -
Jun HyeSeung,
Hwang Kyujung,
Kim Yunjung,
Park Taesun
Publication year - 2008
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2008.220
Subject(s) - adipose tissue , protein phosphatase 2 , medicine , endocrinology , protein kinase b , pi3k/akt/mtor pathway , insulin resistance , western blot , insulin receptor , chemistry , phosphorylation , insulin , phosphatase , signal transduction , biology , gene , biochemistry
Objective: The aim of this study was to investigate a possible link between high‐fat diet (HFD)–induced obesity and the expression of protein phosphatase 2A (PP2A) and Cdc42‐interacting protein 4 (CIP4) proteins, potential downstream components of the IRS/PI3K/AKT and CAP/Cbl/TC10 pathway, respectively, in the visceral adipose tissue. Methods and Procedures: Twenty male Sprague‐Dawley rats were randomly divided into two groups and were given either HFD or the normal diet (ND) for 8 weeks. The HFD‐induced changes in the expression of the epididymal adipose tissue genes involved in the insulin‐signaling pathways were evaluated using real‐time reverse‐transcription PCR and western blot analysis. Results: The exposure of rats to HFD for 8 weeks resulted in a significant increase in the expression of PP2A at both the transcriptional and translational levels, along with a marked reduction in the levels of phosphorylated AKT and insulin receptor substrate‐1 (IRS‐1) in the cytosol of visceral adipocytes, compared with the ND rats. Besides, there were significant HFD‐induced decreases in the mRNA and protein levels of CIP4 and TC10 in the adipose tissue of rats. Discussion: These data suggest that HFD might have a relevance to insulin resistance by increasing the expression of PP2A, an inhibitor of AKT activity in the phosphatidylinositol 3‐kinase (PI3K)/AKT pathway, and also by suppressing the expression of TC10 and CIP4, downstream effectors of the Cbl/CAP/TC10 insulin‐signaling cascade in the visceral adipose tissue.