The glucagon-like peptide-2 receptor mediates direct inhibition of cellular apoptosis via a cAMP-dependent protein kinase-independent pathway.
Glucagon and the glucagon-like peptides regulate metabolic functions via signaling through a glucagon receptor subfamily of G protein-coupled receptors. Activation of glucagon-like peptide-2 receptor (GLP-2R) signaling maintains the integrity of the intestinal epithelial mucosa via regulation of crypt cell proliferation. Because GLP-2 decreases mortality and reduces intestinal apoptosis in rodents after experimental injury, we examined whether GLP-2R signaling directly modifies the cellular response to external injury. We show here that activation of GLP-2R signaling inhibits cycloheximide-induced apoptosis in baby hamster kidney fibroblasts expressing a transfected GLP-2 receptor. GLP-2 reduced DNA fragmentation and improved cell survival, in association with reduced activation of caspase-3 and decreased poly(ADP-ribose) polymerase cleavage and reduced caspase-8 and caspase-9-like activities. Both GLP-2 and forskolin reduced mitochondrial cytochrome c release and decreased the cycloheximide-induced cleavage of caspase-3 in the presence or absence of the PKA inhibitor H-89. Similarly, GLP-2 increased cell survival following cycloheximide in the presence of the kinase inhibitors PD98054 and LY294002. These findings provide evidence that signaling through G protein-coupled receptors of the glucagon superfamily is directly linked to regulation of apoptosis and suggest the existence of a cAMP-dependent protein kinase-, phosphatidylinositol 3-kinase-, and mitogen-activated protein kinase-independent pathway coupling GLP-2R signaling to caspase inhibition and cell survival.
Yusta
B
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Department of Medicine, Banting and Best Diabetes Centre, Toronto General Hospital, University of Toronto, Toronto, Ontario M5G 2C4, Canada.
Boushey
R P
RP
Drucker
D J
DJ
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D002867:Chromones / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D053938:DNA Fragmentation; D004587:Electrophoresis, Agar Gel; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004848:Epithelium / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D053767:Glucagon-Like Peptide 2; D000067757:Glucagon-Like Peptide-1 Receptor; D004763:Glucagon-Like Peptides; D007413:Intestinal Mucosa / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000201:enzymology; D009025:Morpholines / Q000494:pharmacology; D010455:Peptides / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism; D018027:Receptors, Glucagon / Q000502:physiology*; D015398:Signal Transduction; D013449:Sulfonamides; D013997:Time Factors; D014162:Transfection
D000590:Amino Acid Chloromethyl Ketones; D002867:Chromones; D015853:Cysteine Proteinase Inhibitors; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D005419:Flavonoids; D053767:Glucagon-Like Peptide 2; D000067757:Glucagon-Like Peptide-1 Receptor; D007546:Isoquinolines; D009025:Morpholines; D010455:Peptides; D011500:Protein Synthesis Inhibitors; D011956:Receptors, Cell Surface; D018027:Receptors, Glucagon; D013449:Sulfonamides; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D005576:Colforsin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004763:Glucagon-Like Peptides; D003513:Cycloheximide; D011065:Poly(ADP-ribose) Polymerases; D017868:Cyclic AMP-Dependent Protein Kinases; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one