GLP-1 receptor stimulation preserves primary cortical and dopaminergic neurons in cellular and rodent models of stroke and Parkinsonism.

Abstract

Glucagon-like peptide-1 (GLP-1) is an endogenous insulinotropic peptide secreted from the gastrointestinal tract in response to food intake. It enhances pancreatic islet beta-cell proliferation and glucose-dependent insulin secretion, and lowers blood glucose and food intake in patients with type 2 diabetes mellitus (T2DM). A long-acting GLP-1 receptor (GLP-1R) agonist, exendin-4 (Ex-4), is the first of this new class of antihyperglycemia drugs approved to treat T2DM. GLP-1Rs are coupled to the cAMP second messenger pathway and, along with pancreatic cells, are expressed within the nervous system of rodents and humans, where receptor activation elicits neurotrophic actions. We detected GLP-1R mRNA expression in both cultured embryonic primary cerebral cortical and ventral mesencephalic (dopaminergic) neurons. These cells are vulnerable to hypoxia- and 6-hydroxydopamine-induced cell death, respectively. We found that GLP-1 and Ex-4 conferred protection in these cells, but not in cells from Glp1r knockout (-/-) mice. Administration of Ex-4 reduced brain damage and improved functional outcome in a transient middle cerebral artery occlusion stroke model. Ex-4 treatment also protected dopaminergic neurons against degeneration, preserved dopamine levels, and improved motor function in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease (PD). Our findings demonstrate that Ex-4 can protect neurons against metabolic and oxidative insults, and they provide preclinical support for the therapeutic potential for Ex-4 in the treatment of stroke and PD.

• Authors: Yazhou Li, TracyAnn Perry, Mark S Kindy, Brandon K Harvey, David Tweedie, Harold W Holloway, Kathleen Powers, Hui Shen, Josephine M Egan, Kumar Sambamurti, Arnold Brossi, Debomoy K Lahiri, Mark P Mattson, Barry J Hoffer, Yun Wang, Nigel H Greig
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 106 Issue 4 Pg. 1285-90 (Jan 27 2009) ISSN: 1091-6490 [Electronic] United States
• PMID: 19164583 (Publication Type: Journal Article, Research Support, N.I.H., Intramural)

Chemical References

• GLP1R protein, human
• Glp1r protein, mouse
• Glp1r protein, rat
• Glucagon-Like Peptide-1 Receptor
• Peptides
• Receptors, Glucagon
• Venoms
• Exenatide
• 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
• Dopamine

Topics

• 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
• Animals
• Brain Infarction (drug therapy, pathology)
• Cell Death (drug effects)
• Cell Hypoxia (drug effects)
• Cells, Cultured
• Cerebral Cortex (cytology)
• Cytoprotection (drug effects)
• Disease Models, Animal
• Dopamine (metabolism)
• Embryo, Mammalian (cytology)
• Exenatide
• Gene Expression Regulation (drug effects)
• Glucagon-Like Peptide-1 Receptor
• Humans
• Mesencephalon (cytology)
• Mice
• Neurons (drug effects, pathology)
• Parkinson Disease (drug therapy, metabolism, pathology)
• Peptides (pharmacology, therapeutic use)
• Rats
• Receptors, Glucagon (genetics, metabolism)
• Stroke (drug therapy, metabolism, pathology)
• Treatment Outcome
• Venoms (pharmacology, therapeutic use)