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Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets

OBJECTIVE: In type 2 diabetes, chronic hyperglycemia is detrimental to β-cells, causing apoptosis and impaired insulin secretion. The transcription factor cAMP-responsive element–binding protein (CREB) is crucial for β-cell survival and function. We investigated whether prolonged exposure of β-cells...

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Autores principales: Costes, Safia, Vandewalle, Brigitte, Tourrel-Cuzin, Cécile, Broca, Christophe, Linck, Nathalie, Bertrand, Gyslaine, Kerr-Conte, Julie, Portha, Bernard, Pattou, François, Bockaert, Joel, Dalle, Stéphane
Formato: Texto
Lenguaje:English
Publicado: American Diabetes Association 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671045/
https://www.ncbi.nlm.nih.gov/pubmed/19223597
http://dx.doi.org/10.2337/db08-0926
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author Costes, Safia
Vandewalle, Brigitte
Tourrel-Cuzin, Cécile
Broca, Christophe
Linck, Nathalie
Bertrand, Gyslaine
Kerr-Conte, Julie
Portha, Bernard
Pattou, François
Bockaert, Joel
Dalle, Stéphane
author_facet Costes, Safia
Vandewalle, Brigitte
Tourrel-Cuzin, Cécile
Broca, Christophe
Linck, Nathalie
Bertrand, Gyslaine
Kerr-Conte, Julie
Portha, Bernard
Pattou, François
Bockaert, Joel
Dalle, Stéphane
author_sort Costes, Safia
collection PubMed
description OBJECTIVE: In type 2 diabetes, chronic hyperglycemia is detrimental to β-cells, causing apoptosis and impaired insulin secretion. The transcription factor cAMP-responsive element–binding protein (CREB) is crucial for β-cell survival and function. We investigated whether prolonged exposure of β-cells to high glucose affects the functional integrity of CREB. RESEARCH DESIGN AND METHODS: INS-1E cells and rat and human islets were used. Gene expression was analyzed by RT-PCR and Western blotting. Apoptosis was detected by cleaved caspase-3 emergence, DNA fragmentation, and electron microscopy. RESULTS: Chronic exposure of INS-1E cells and rat and human islets to high glucose resulted in decreased CREB protein expression, phosphorylation, and transcriptional activity associated with apoptosis and impaired β-cell function. High-glucose treatment increased CREB polyubiquitination, while treatment of INS-1E cells with the proteasome inhibitor MG-132 prevented the decrease in CREB content. The emergence of apoptosis in INS-1E cells with decreased CREB protein expression knocked down by small interfering RNA suggested that loss of CREB protein content induced by high glucose contributes to β-cell apoptosis. Loading INS-1E cells or human islets with a cell-permeable peptide mimicking the proteasomal targeting sequence of CREB blocked CREB degradation and protected INS-1E cells and human islets from apoptosis induced by high glucose. The insulin secretion in response to glucose and the insulin content were preserved in human islets exposed to high glucose and loaded with the peptide. CONCLUSIONS: These studies demonstrate that the CREB degradation by the ubiquitin-proteasome pathway contributes to β-cell dysfunction and death upon glucotoxicity and provide new insight into the cellular mechanisms of glucotoxicity.
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spelling pubmed-26710452010-05-01 Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets Costes, Safia Vandewalle, Brigitte Tourrel-Cuzin, Cécile Broca, Christophe Linck, Nathalie Bertrand, Gyslaine Kerr-Conte, Julie Portha, Bernard Pattou, François Bockaert, Joel Dalle, Stéphane Diabetes Original Article OBJECTIVE: In type 2 diabetes, chronic hyperglycemia is detrimental to β-cells, causing apoptosis and impaired insulin secretion. The transcription factor cAMP-responsive element–binding protein (CREB) is crucial for β-cell survival and function. We investigated whether prolonged exposure of β-cells to high glucose affects the functional integrity of CREB. RESEARCH DESIGN AND METHODS: INS-1E cells and rat and human islets were used. Gene expression was analyzed by RT-PCR and Western blotting. Apoptosis was detected by cleaved caspase-3 emergence, DNA fragmentation, and electron microscopy. RESULTS: Chronic exposure of INS-1E cells and rat and human islets to high glucose resulted in decreased CREB protein expression, phosphorylation, and transcriptional activity associated with apoptosis and impaired β-cell function. High-glucose treatment increased CREB polyubiquitination, while treatment of INS-1E cells with the proteasome inhibitor MG-132 prevented the decrease in CREB content. The emergence of apoptosis in INS-1E cells with decreased CREB protein expression knocked down by small interfering RNA suggested that loss of CREB protein content induced by high glucose contributes to β-cell apoptosis. Loading INS-1E cells or human islets with a cell-permeable peptide mimicking the proteasomal targeting sequence of CREB blocked CREB degradation and protected INS-1E cells and human islets from apoptosis induced by high glucose. The insulin secretion in response to glucose and the insulin content were preserved in human islets exposed to high glucose and loaded with the peptide. CONCLUSIONS: These studies demonstrate that the CREB degradation by the ubiquitin-proteasome pathway contributes to β-cell dysfunction and death upon glucotoxicity and provide new insight into the cellular mechanisms of glucotoxicity. American Diabetes Association 2009-05 2009-02-17 /pmc/articles/PMC2671045/ /pubmed/19223597 http://dx.doi.org/10.2337/db08-0926 Text en © 2009 by the American Diabetes Association.
spellingShingle Original Article
Costes, Safia
Vandewalle, Brigitte
Tourrel-Cuzin, Cécile
Broca, Christophe
Linck, Nathalie
Bertrand, Gyslaine
Kerr-Conte, Julie
Portha, Bernard
Pattou, François
Bockaert, Joel
Dalle, Stéphane
Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title_full Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title_fullStr Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title_full_unstemmed Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title_short Degradation of cAMP-Responsive Element–Binding Protein by the Ubiquitin-Proteasome Pathway Contributes to Glucotoxicity in β-Cells and Human Pancreatic Islets
title_sort degradation of camp-responsive element–binding protein by the ubiquitin-proteasome pathway contributes to glucotoxicity in β-cells and human pancreatic islets
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671045/
https://www.ncbi.nlm.nih.gov/pubmed/19223597
http://dx.doi.org/10.2337/db08-0926
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