| First Author | Linnemann AK | Year | 2015 |
| Journal | Mol Endocrinol | Volume | 29 |
| Issue | 7 | Pages | 978-87 |
| PubMed ID | 25984632 | Mgi Jnum | J:232909 |
| Mgi Id | MGI:5780403 | Doi | 10.1210/me.2015-1030 |
| Citation | Linnemann AK, et al. (2015) Glucagon-Like Peptide-1 Regulates Cholecystokinin Production in beta-Cells to Protect From Apoptosis. Mol Endocrinol 29(7):978-87 |
| abstractText | Cholecystokinin (CCK) is a classic gut hormone that is also expressed in the pancreatic islet, where it is highly up-regulated with obesity. Loss of CCK results in increased beta-cell apoptosis in obese mice. Similarly, islet alpha-cells produce increased amounts of another gut peptide, glucagon-like peptide 1 (GLP-1), in response to cytokine and nutrient stimulation. GLP-1 also protects beta-cells from apoptosis via cAMP-mediated mechanisms. Therefore, we hypothesized that the activation of islet-derived CCK and GLP-1 may be linked. We show here that both human and mouse islets secrete active GLP-1 as a function of body mass index/obesity. Furthermore, GLP-1 can rapidly stimulate beta-cell CCK production and secretion through direct targeting by the cAMP-modulated transcription factor, cAMP response element binding protein (CREB). We find that cAMP-mediated signaling is required for Cck expression, but CCK regulation by cAMP does not require stimulatory levels of glucose or insulin secretion. We also show that CREB directly targets the Cck promoter in islets from obese (Leptin(ob/ob)) mice. Finally, we demonstrate that the ability of GLP-1 to protect beta-cells from cytokine-induced apoptosis is partially dependent on CCK receptor signaling. Taken together, our work suggests that in obesity, active GLP-1 produced in the islet stimulates CCK production and secretion in a paracrine manner via cAMP and CREB. This intraislet incretin loop may be one mechanism whereby GLP-1 protects beta-cells from apoptosis. |
