Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells.
BACKGROUND:Glucose increases the expression of glycolytic enzymes and other hypoxia-response genes in pancreatic beta-cells. Here, we tested whether this effect results from the activation of Hypoxia-Inducible-factors (HIF) 1 and 2 in a hypoxia-dependent manner. METHODOLOGY/PRINCIPAL FINDINGS:Isolat...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2012-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3250482?pdf=render |
| _version_ | 1811223818170007552 |
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| author | Mohammed Bensellam Bertrand Duvillié Galyna Rybachuk D Ross Laybutt Christophe Magnan Yves Guiot Jacques Pouysségur Jean-Christophe Jonas |
| author_facet | Mohammed Bensellam Bertrand Duvillié Galyna Rybachuk D Ross Laybutt Christophe Magnan Yves Guiot Jacques Pouysségur Jean-Christophe Jonas |
| author_sort | Mohammed Bensellam |
| collection | DOAJ |
| description | BACKGROUND:Glucose increases the expression of glycolytic enzymes and other hypoxia-response genes in pancreatic beta-cells. Here, we tested whether this effect results from the activation of Hypoxia-Inducible-factors (HIF) 1 and 2 in a hypoxia-dependent manner. METHODOLOGY/PRINCIPAL FINDINGS:Isolated rat islets and insulin-secreting INS-1E cells were stimulated with nutrients at various pO₂ values or treated with the HIF activator CoCl₂. HIF-target gene mRNA levels and HIF subunit protein levels were measured by real-time RT-PCR, Western Blot and immunohistochemistry. The formation of pimonidazole-protein adducts was used as an indicator of hypoxia. In INS-1E and islet beta-cells, glucose concentration-dependently stimulated formation of pimonidazole-protein adducts, HIF1 and HIF2 nuclear expression and HIF-target gene mRNA levels to a lesser extent than CoCl₂ or a four-fold reduction in pO₂. Islets also showed signs of HIF activation in diabetic Lepr(db/db) but not non-diabetic Lepr(db/+) mice. In vitro, these glucose effects were reproduced by nutrient secretagogues that bypass glycolysis, and were inhibited by a three-fold increase in pO₂ or by inhibitors of Ca²⁺ influx and insulin secretion. In INS-1E cells, small interfering RNA-mediated knockdown of Hif1α and Hif2α, alone or in combination, indicated that the stimulation of glycolytic enzyme mRNA levels depended on both HIF isoforms while the vasodilating peptide adrenomedullin was a HIF2-specific target gene. CONCLUSIONS/SIGNIFICANCE:Glucose-induced O₂ consumption creates an intracellular hypoxia that activates HIF1 and HIF2 in rat beta-cells, and this glucose effect contributes, together with the activation of other transcription factors, to the glucose stimulation of expression of some glycolytic enzymes and other hypoxia response genes. |
| first_indexed | 2024-04-12T08:39:51Z |
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| id | doaj.art-a46e96628aa440de8f3eca69bb7ab864 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-12T08:39:51Z |
| publishDate | 2012-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-a46e96628aa440de8f3eca69bb7ab8642022-12-22T03:39:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0171e2980710.1371/journal.pone.0029807Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells.Mohammed BensellamBertrand DuvilliéGalyna RybachukD Ross LaybuttChristophe MagnanYves GuiotJacques PouysségurJean-Christophe JonasBACKGROUND:Glucose increases the expression of glycolytic enzymes and other hypoxia-response genes in pancreatic beta-cells. Here, we tested whether this effect results from the activation of Hypoxia-Inducible-factors (HIF) 1 and 2 in a hypoxia-dependent manner. METHODOLOGY/PRINCIPAL FINDINGS:Isolated rat islets and insulin-secreting INS-1E cells were stimulated with nutrients at various pO₂ values or treated with the HIF activator CoCl₂. HIF-target gene mRNA levels and HIF subunit protein levels were measured by real-time RT-PCR, Western Blot and immunohistochemistry. The formation of pimonidazole-protein adducts was used as an indicator of hypoxia. In INS-1E and islet beta-cells, glucose concentration-dependently stimulated formation of pimonidazole-protein adducts, HIF1 and HIF2 nuclear expression and HIF-target gene mRNA levels to a lesser extent than CoCl₂ or a four-fold reduction in pO₂. Islets also showed signs of HIF activation in diabetic Lepr(db/db) but not non-diabetic Lepr(db/+) mice. In vitro, these glucose effects were reproduced by nutrient secretagogues that bypass glycolysis, and were inhibited by a three-fold increase in pO₂ or by inhibitors of Ca²⁺ influx and insulin secretion. In INS-1E cells, small interfering RNA-mediated knockdown of Hif1α and Hif2α, alone or in combination, indicated that the stimulation of glycolytic enzyme mRNA levels depended on both HIF isoforms while the vasodilating peptide adrenomedullin was a HIF2-specific target gene. CONCLUSIONS/SIGNIFICANCE:Glucose-induced O₂ consumption creates an intracellular hypoxia that activates HIF1 and HIF2 in rat beta-cells, and this glucose effect contributes, together with the activation of other transcription factors, to the glucose stimulation of expression of some glycolytic enzymes and other hypoxia response genes.http://europepmc.org/articles/PMC3250482?pdf=render |
| spellingShingle | Mohammed Bensellam Bertrand Duvillié Galyna Rybachuk D Ross Laybutt Christophe Magnan Yves Guiot Jacques Pouysségur Jean-Christophe Jonas Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. PLoS ONE |
| title | Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. |
| title_full | Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. |
| title_fullStr | Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. |
| title_full_unstemmed | Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. |
| title_short | Glucose-induced O₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin-secreting pancreatic beta-cells. |
| title_sort | glucose induced o₂ consumption activates hypoxia inducible factors 1 and 2 in rat insulin secreting pancreatic beta cells |
| url | http://europepmc.org/articles/PMC3250482?pdf=render |
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