Glucagon-like peptide-1 promotes DNA synthesis, activates phosphatidylinositol 3-kinase and increases transcription factor pancreatic and duodenal homeobox gene 1 (PDX-1) DNA binding activity in beta (INS-1)-cells.
Details
Serval ID
serval:BIB_6FE113E9F1AC
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Glucagon-like peptide-1 promotes DNA synthesis, activates phosphatidylinositol 3-kinase and increases transcription factor pancreatic and duodenal homeobox gene 1 (PDX-1) DNA binding activity in beta (INS-1)-cells.
Journal
Diabetologia
ISSN
0012-186X (Print)
ISSN-L
0012-186X
Publication state
Published
Issued date
07/1999
Peer-reviewed
Oui
Volume
42
Number
7
Pages
856-864
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Publication Status: ppublish
Abstract
Glucagon-like peptide-1 is a potent glucoincretin hormone and a potentially important drug in the treatment of Type II (non-insulin-dependent) diabetes mellitus. We have investigated whether it acts as a growth factor in beta (INS-1)-cells and have studied the signalling pathways and transcription factors implicated in this process.
Cell proliferation was assessed by tritiated thymidine incorporation measurements. We have examined the action of glucagon-like peptide-1 on the enzymatic activity of phosphatidylinositol 3-kinase. The DNA binding activity of transcription factors was investigated by electrophoretic mobility shift assay. Measurements of mRNA were done using the northern technique.
Glucagon-like peptide-1 caused an increase in tritiated thymidine incorporation in beta (INS-1)-cells and phosphatidylinositol 3-kinase activity in a dose-dependent manner non-additively with glucose. The phosphatidylinositol 3-kinase inhibitors wortmannin and LY294002 blocked the effects of glucagon-like peptide-1 on DNA synthesis. Transcription factor pancreatic and duodenal homebox gene 1 (PDX-1) DNA binding activity was increased by glucagon-like peptide-1 at 3 or 11 mmol/l glucose and the phosphatidylinositol 3-kinase inhibitor LY294002 suppressed the action of glucagon-like peptide-1 on PDX-1 DNA binding activity. Glucagon-like peptide-1 and glucose alone did not change activating protein-1 DNA binding activity. They synergised, however, to increase the activity of activating protein-1. Glucagon-like peptide-1 also increased the expression of PDX-1, glucose transporter 2, glucokinase and insulin mRNAs. Finally, glucagon-like peptide-1 increased the incorporation of tritiated thymidine in isolated rat islets.
The results suggest that glucagon-like peptide-1 may act as a growth factor for the beta cell by a phosphatidylinositol 3-kinase mediated event. Glucagon-like peptide-1 could also regulate the expression of the insulin gene and genes encoding enzymes implicated in glucose transport and metabolism through the phosphatidylinositol 3-kinase/PDX-1 transduction signalling pathway.
Cell proliferation was assessed by tritiated thymidine incorporation measurements. We have examined the action of glucagon-like peptide-1 on the enzymatic activity of phosphatidylinositol 3-kinase. The DNA binding activity of transcription factors was investigated by electrophoretic mobility shift assay. Measurements of mRNA were done using the northern technique.
Glucagon-like peptide-1 caused an increase in tritiated thymidine incorporation in beta (INS-1)-cells and phosphatidylinositol 3-kinase activity in a dose-dependent manner non-additively with glucose. The phosphatidylinositol 3-kinase inhibitors wortmannin and LY294002 blocked the effects of glucagon-like peptide-1 on DNA synthesis. Transcription factor pancreatic and duodenal homebox gene 1 (PDX-1) DNA binding activity was increased by glucagon-like peptide-1 at 3 or 11 mmol/l glucose and the phosphatidylinositol 3-kinase inhibitor LY294002 suppressed the action of glucagon-like peptide-1 on PDX-1 DNA binding activity. Glucagon-like peptide-1 and glucose alone did not change activating protein-1 DNA binding activity. They synergised, however, to increase the activity of activating protein-1. Glucagon-like peptide-1 also increased the expression of PDX-1, glucose transporter 2, glucokinase and insulin mRNAs. Finally, glucagon-like peptide-1 increased the incorporation of tritiated thymidine in isolated rat islets.
The results suggest that glucagon-like peptide-1 may act as a growth factor for the beta cell by a phosphatidylinositol 3-kinase mediated event. Glucagon-like peptide-1 could also regulate the expression of the insulin gene and genes encoding enzymes implicated in glucose transport and metabolism through the phosphatidylinositol 3-kinase/PDX-1 transduction signalling pathway.
Keywords
Androstadienes, Animals, Chromones, DNA/biosynthesis, DNA/drug effects, DNA-Binding Proteins/metabolism, Duodenum/metabolism, Enzyme Activation/drug effects, Enzyme Inhibitors, Genes, Homeobox, Glucagon/genetics, Glucagon/pharmacology, Glucagon-Like Peptide 1, Glucose/pharmacology, Humans, Insulin/genetics, Islets of Langerhans/drug effects, Islets of Langerhans/growth & development, Islets of Langerhans/physiology, Morpholines, Nifedipine/pharmacology, Pancreas/metabolism, Peptide Fragments/genetics, Peptide Fragments/pharmacology, Phosphatidylinositol 3-Kinases/antagonists & inhibitors, Phosphatidylinositol 3-Kinases/metabolism, Potassium Chloride/pharmacology, Protein Precursors/genetics, Protein Precursors/pharmacology, RNA, Messenger/analysis, Rats, Rats, Wistar, Signal Transduction, Transcription Factor AP-1/metabolism, Transcription Factors/genetics, Tumor Cells, Cultured
Pubmed
Web of science
Open Access
Yes
Create date
20/09/2017 13:47
Last modification date
20/08/2019 15:28
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