Necdin-E2F4 interaction provides insulin-sensitizing effect after weight loss induced by gastric bypass surgery
| Autor: | Anna Spagnoli, Michael J. Muehlbauer, Alfonso Torquati, Zehra Pamuklar, Jiegen Chen |
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| Rok vydání: | 2011 |
| Předmět: |
Adult
Male medicine.medical_specialty medicine.medical_treatment Gastric Bypass Adipose tissue Nerve Tissue Proteins E2F4 Transcription Factor Article chemistry.chemical_compound Insulin resistance Downregulation and upregulation Internal medicine Adipocyte Gene expression Weight Loss medicine Adipocytes Humans Prospective Studies E2F4 Cells Cultured business.industry Insulin nutritional and metabolic diseases Nuclear Proteins Middle Aged medicine.disease Surgery Obesity Morbid Endocrinology chemistry Case-Control Studies Female Signal transduction Insulin Resistance business |
| Zdroj: | Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 9(1) |
| ISSN: | 1878-7533 |
| Popis: | Background The 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. Methods Clinical 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. Results Free 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). Conclusion After 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. |
| Databáze: | OpenAIRE |
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