Necdin–E2F4 interaction provides insulin-sensitizing effect after weight loss induced by gastric bypass surgery |
| |
Authors: | Zehra N Pamuklar Jiegen Chen Michael Muehlbauer Anna Spagnoli Alfonso Torquati |
| |
Institution: | 1. Department of Surgery, Duke University School of Medicine, Durham, North Carolina;2. Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina;3. Department of Pediatrics, University of North Carolina, Chapel Hill, School of Medicine, Chapel Hill, North Carolina |
| |
Abstract: | BackgroundThe insulin-like growth factor-1 (IGF-1) signaling pathway promotes adipocyte differentiation and, therefore, insulin sensitivity by suppression of necdin expression, which represses peroxisome proliferator-activated receptor-gamma promoter activity by interaction with E2F4 in mouse adipocytes. The aim of the present study was to test the hypothesis that this pathway represents one of the mechanisms by which Roux-en-Y gastric bypass surgery (RYGB) induces resolution of insulin resistance.MethodsClinical samples were collected and the key biomarkers measured to test the hypothesis that the IGF-1 pathway represents 1 of the mechanisms by which RYGB induces resolution of insulin resistance in obese individuals.ResultsFree IGF-1 levels were significantly greater in the post-RYGB patients than in the pre-RYGB obese patients (2.55 ± 1.54 versus 1.32 ± .65 μg/L, P = .03) and similar to that in normal weight controls (2.54 ± 1.27 μg/L). Necdin and E2F4 gene expression in the adipose tissue was significantly downregulated after RYGB compared with obese and were similar to the levels observed in the controls. In mature human adipocytes cultured in vitro, treatment with des-IGF-1 induced downregulation of necdin and E2F4 gene expression in a dose-dependent manner (P = .01).ConclusionAfter RYGB, the insulin/IGF-1 signaling pathway is activated and could account for the observed decrease in the expression of necdin, which represses peroxisome proliferator-activated receptor-gamma promoter activity by interaction with E2F4. This could represent one of the mechanisms that induce resolution of insulin resistance after RYGB. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|