Increasing uncoupling protein-2 in pancreatic beta cells does not alter glucose-induced insulin secretion but decreases production of reactive oxygen species
| Autor: | Helene Perreten, Patrick A. Keller, Pedro Luis Herrera, Claes B. Wollheim, Asllan Gjinovci, Nathalie Davis-Lameloise, Nathalie Produit-Zengaffinen, Françoise Assimacopoulos-Jeannet, Patrick Muzzin, Dominique Becard |
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| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Cellular respiration Endocrinology Diabetes and Metabolism medicine.medical_treatment Adenosine Triphosphate/metabolism Cell Respiration Mice Transgenic Mitochondrion Biology Carbohydrate metabolism Ion Channels Cell Line Doxycycline/pharmacology Mitochondrial Proteins chemistry.chemical_compound Mice Insulin-Secreting Cells/ metabolism Adenosine Triphosphate Internal medicine Insulin-Secreting Cells Internal Medicine medicine Mitochondrial Proteins/genetics/ metabolism Animals Insulin Secretion Uncoupling Protein 2 Cell Respiration/physiology Pancreatic hormone chemistry.chemical_classification ddc:616 Membrane Potential Mitochondrial Reactive oxygen species Insulin/ metabolism Membrane Potential Mitochondrial/physiology Glucose/metabolism/ pharmacology Endocrinology Ion Channels/genetics/ metabolism Glucose chemistry Doxycycline Reactive Oxygen Species/ metabolism Female Reactive Oxygen Species Adenosine triphosphate |
| Zdroj: | Diabetologia, Vol. 50, No 1 (2007) pp. 84-93 |
| ISSN: | 0012-186X |
| Popis: | AIMS/HYPOTHESIS: Levels of uncoupling protein-2 (UCP2) are regulated in the pancreatic beta cells and an increase in the protein level has been associated with mitochondrial uncoupling and alteration in glucose-stimulated insulin secretion. However, it is not clear whether an increase in uncoupling protein-2 per se induces mitochondrial uncoupling and affects ATP generation and insulin secretion. MATERIALS AND METHODS: Transgenic mice with beta cell-specific overexpression of the human UCP2 gene and INS-1 cells with doxycycline-inducible overproduction of the protein were generated and the consequences of increased levels of UCP2 on glucose-induced insulin secretion and on parameters reflecting mitochondrial uncoupling were determined. RESULTS: In transgenic mice, an increase in beta cell UCP2 protein concentration did not significantly modify plasma glucose and insulin levels. Glucose-induced insulin secretion and elevation in the ATP/ADP ratio were unaltered by an increase in UCP2 level. In INS-1 cells, a similar increase in UCP2 level did not modify glucose-induced insulin secretion, cytosolic ATP and ATP/ADP ratio, or glucose oxidation. Increased levels of UCP2 did not modify the mitochondrial membrane potential and oxygen consumption. Increased UCP2 levels decreased cytokine-induced production of reactive oxygen species. CONCLUSION/INTERPRETATION: The results obtained in transgenic mice and in the beta cell line do not support the hypothesis that an increase in UCP2 protein per se uncouples the mitochondria and decreases glucose-induced insulin secretion. In contrast, the observation that increased UCP2 levels decrease cytokine-induced production of reactive oxygen species indicates a potential protective effect of the protein on beta cells, as observed in other cell types. |
| Databáze: | OpenAIRE |
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