| Autor: |
K. Suba, Y. Patel, A. Martin-Alonso, B. Hansen, X. Xu, A. Roberts, M. Norton, P. Chung, J. Shrewsbury, R. Kwok, V. Kalogianni, S. Chen, X. Liu, K. Kalyviotis, G.A. Rutter, B. Jones, J. Minnion, B.M. Owen, P. Pantazis, W. Distaso, D.J. Drucker, T.M. Tan, S.R. Bloom, K.G. Murphy, V. Salem |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
|
| Zdroj: |
Molecular Metabolism, Vol 85, Iss , Pp 101947- (2024) |
| Druh dokumentu: |
article |
| ISSN: |
2212-8778 |
| DOI: |
10.1016/j.molmet.2024.101947 |
| Popis: |
Objective: Type 2 diabetes (T2D) is characterised by the loss of first-phase insulin secretion. We studied mice with β-cell selective loss of the glucagon receptor (Gcgrfl/fl X Ins-1Cre), to investigate the role of intra-islet glucagon receptor (GCGR) signalling on pan-islet [Ca2+]I activity and insulin secretion. Methods: Metabolic profiling was conducted on Gcgrβ-cell−/− and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for β-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged in vitro and in vivo. Wild-type mice were transplanted with islets expressing GCaMP6f in β-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment. Results: Gcgrβ-cell−/− mice exhibited higher glucose levels following intraperitoneal glucose challenge (control 12.7 mmol/L ± 0.6 vs. Gcgrβ-cell−/− 15.4 mmol/L ± 0.0 at 15 min, p = 0.002); fasting glycaemia was not different to controls. In vitro, Gcgrβ-cell−/− islets showed profound loss of pan-islet [Ca2+]I waves in response to glucose which was only partially rescued in vivo. Diet induced obesity and hyperglycaemia also resulted in a loss of co-ordinated [Ca2+]I waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n = 8). Conclusion: These data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised [Ca2+]I waves and support a possible therapeutic role for glucagonergic agents to restore the insulin secretory capacity lost in T2D. |
| Databáze: |
Directory of Open Access Journals |
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