An enzymatically stable GIP/xenin hybrid peptide restores GIP sensitivity, enhances beta cell function and improves glucose homeostasis in high-fat-fed mice
Journal article
Authors | Hasib, Annie, Ng, Tony, Gault, Victor A., Khan, Dawood, Parthsarathy, Vadivel, Flatt, Peter and Irwin, Nigel |
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Abstract | AIMS/HYPOTHESIS: Glucose-dependent insulinotropic polypeptide (GIP) and xenin, regulatory gut hormones secreted from enteroendocrine K cells, exert important effects on metabolism. In addition, xenin potentiates the biological actions of GIP. The present study assessed the actions and therapeutic utility of a (DAla2)GIP/xenin-8-Gln hybrid peptide, in comparison with the parent peptides (DAla2)GIP and xenin-8-Gln. METHODS: Following confirmation of enzymatic stability, insulin secretory activity of (DAla2)GIP/xenin-8-Gln was assessed in BRIN-BD11 beta cells. Acute and persistent glucose-lowering and insulin-releasing effects were then examined in vivo. Finally, the metabolic benefits of twice daily injection of (DAla2)GIP/xenin-8-Gln was determined in high-fat-fed mice. RESULTS: All peptides significantly (p < 0.05 to p < 0.001) enhanced in vitro insulin secretion from pancreatic clonal BRIN-BD11 cells, with xenin (and particularly GIP)-related signalling pathways, being important for this action. Administration of (DAla2)GIP or (DAla2)GIP/xenin-8-Gln in combination with glucose significantly (p < 0.05) lowered blood glucose and increased plasma insulin in mice, with a protracted response of up to 4 h. All treatments elicited appetite-suppressive effects (p < 0.05), particularly (DAla2)GIP/xenin-8-Gln and xenin-8-Gln at elevated doses of 250 nmol/kg. Twice-daily administration of (DAla2)GIP/xenin-8-Gln or (DAla2)GIP for 21 days to high-fat-fed mice returned circulating blood glucose to lean control levels. In addition, (DAla2)GIP/xenin-8-Gln treatment significantly (p < 0.05) reduced glycaemic levels during a 24 h glucose profile assessment. Neither of the treatment regimens had an effect on body weight, energy intake or circulating insulin concentrations. However, insulin sensitivity was significantly (p < 0.001) improved by both treatments. Interestingly, GIP-mediated glucose-lowering (p < 0.05) and insulin-releasing (p < 0.05 to p < 0.01) effects were substantially improved by (DAla2)GIP and (DAla2)GIP/xenin-8-Gln treatment. Pancreatic islet and beta cell area (p < 0.001), as well as pancreatic insulin content (p < 0.05), were augmented in (DAla2)GIP/xenin-8-Gln-treated mice, related to enhanced proliferation and decreased apoptosis of beta cells, whereas (DAla2)GIP evoked increases (p < 0.05 to p < 0.01) in islet number. CONCLUSIONS/INTERPRETATION: These studies highlight the clear potential of GIP/xenin hybrids for the treatment of type 2 diabetes. |
Keywords | glucose; high-fat feeding; hybrid; insulin secretion; xenin |
Year | 2017 |
Journal | Diabetologia |
Journal citation | 60 (2017), pp. 541-552 |
Publisher | Springer |
ISSN | 0012-186X |
Digital Object Identifier (DOI) | https://doi.org/10.1007/s00125-016-4186-y |
Web address (URL) | http://hdl.handle.net/10545/622902 |
hdl:10545/622902 | |
Output status | Published |
Publication dates | 21 Dec 2016 |
Publication process dates | |
Deposited | 16 Aug 2018 |
https://repository.derby.ac.uk/item/9471x/an-enzymatically-stable-gip-xenin-hybrid-peptide-restores-gip-sensitivity-enhances-beta-cell-function-and-improves-glucose-homeostasis-in-high-fat-fed-mice
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