Regulation of Pigment Epithelium-Derived Factor (PEDF), an Insulin Resistance-Inducing Adipocytokine, in 3T3-L1 AdipocytesDaisuke Ito, Kouichi Inukai*, Takashi Sumita, Hiraku Ono, Shigehiro Katayama and Takuya Awata
Division of Endocrinology and Diabetes, Department of Medicine, Saitama Medical School, Morohongo 38, Moroyama, Iruma-gun, Saitama, 350-0495, Japan
- *Corresponding Author:
- Kouichi Inukai
Division of Endocrinology and Diabetes
Department of Medicine, Saitama Medical School
Morohongo 38, Moroyama, Iruma-gun, Saitama, 350-0495, Japan
E-mail: [email protected]
Received date October 03, 2011; Accepted date November 19, 2011; Published date November 23, 2011
Citation: Ito D, Inukai K, Sumita T, Ono H, Katayama S, et al. (2011) Regulation of Pigment Epithelium-Derived Factor (PEDF), an Insulin Resistance-Inducing Adipocytokine, in 3T3-L1 Adipocytes. J Diabetes Metab 2:151. doi:10.4172/2155-6156.1000151
Copyright: © 2011 Ito D, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Pigment epithelium-derived factor (PEDF), secreted by adipocytes, was recently demonstrated to reduce insulin sensitivity and to possibly cause insulin resistance in obesity. In the present study, we investigated the regulation of adipocyte-expressing PEDF to clarify the underlying link between obesity and PEDF expression. We examined PEDF expression in 3T3-L1 adipocytes at both the transcriptional and the protein level using RT-PCR and western blot. First, we examined PEDF expression during 3T3-L1 adipocyte differentiation. PEDF expression peaked in 3T3-L1 fibroblasts and was lowest at 2 days after initiating the induction of differentiation into adipocytes (day 2). Then, PEDF expressions gradually rose until day 10, in parallel with adipocyte differentiation. Exposure of 3T3-L1 adipocytes to a PPARα or PPARγ activator reduced PEDF expression, suggesting these suppressions of PEDF expression to be involved in the mechanism by which PPAR agonists reduce insulin resistance. When 3T3-L1 adipocytes were treated with 0.5 μM H 2 O 2 , PEDF levels were markedly reduced, indicating PEDF expression to be inhibited by oxidative stress. We demonstrated PEDF expression to increase in parallel with adipocyte differentiation and to be negatively regulated by oxidative stress and PPAR agonists.