Open Access

Endogenous GLP-1 as a key self-defense molecule against lipotoxicity in pancreatic islets

  • Authors:
    • Chenghu Huang
    • Li Yuan
    • Shuyi Cao
  • View Affiliations

  • Published online on: May 12, 2015     https://doi.org/10.3892/ijmm.2015.2207
  • Pages: 173-185
  • Copyright: © Huang et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

The number of pro-α cells is known to increase in response to β cell injury and these cells then generate glucagon-like peptide-1 (GLP-1), thus attenuating the development of diabetes. The aim of the present study was to further examine the role and the mechanisms responsible for intra-islet GLP-1 production as a self-protective response against lipotoxicity. The levels of the key enzyme, prohormone convertase 1/3 (PC1/3), as well as the synthesis and release of GLP-1 in models of lipotoxicity were measured. Furthermore, islet viability, apoptosis, oxidative stress and inflammation, as well as islet structure were assessed after altering GLP-1 receptor signaling. Both prolonged exposure to palmitate and a high-fat diet facilitated PC1/3 expression, as well as the synthesis and release of GLP-1 induced by β cell injury and the generation of pro-α cells. Prolonged exposure to palmitate increased reactive oxygen species (ROS) production, and the antioxidant, N-acetylcysteine (NAC), partially prevented the detrimental effects induced by palmitate on β cells, resulting in decreased GLP-1 levels. Furthermore, the inhibition of GLP-1 receptor (GLP-1R) signaling by treatment with exendin‑(9-39) further decreased cell viability, increased cell apoptosis and caused a stronger inhibition of the β cell-specific transcription factor, pancreatic duodenal homeobox 1 (PDX1). Moreover, treatment with the GLP-1R agonist, liraglutide, normalized islet structure and function, resulting in a decrease in cell death and in the amelioration of β cell marker expression. Importantly, liraglutide maintained the oxidative balance and decreased inflammatory factor and p65 expression. Overall, our data demonstrate that an increase in the number of pro-α cells and the activation of the intra-islet GLP-1 system comprise a self-defense mechanism for enhancing β cell survival to combat lipid overload, which is in part mediated by oxidative stress and inflammation.
View Figures
View References

Related Articles

Journal Cover

July-2015
Volume 36 Issue 1

Print ISSN: 1107-3756
Online ISSN:1791-244X

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Huang C, Yuan L and Cao S: Endogenous GLP-1 as a key self-defense molecule against lipotoxicity in pancreatic islets. Int J Mol Med 36: 173-185, 2015
APA
Huang, C., Yuan, L., & Cao, S. (2015). Endogenous GLP-1 as a key self-defense molecule against lipotoxicity in pancreatic islets. International Journal of Molecular Medicine, 36, 173-185. https://doi.org/10.3892/ijmm.2015.2207
MLA
Huang, C., Yuan, L., Cao, S."Endogenous GLP-1 as a key self-defense molecule against lipotoxicity in pancreatic islets". International Journal of Molecular Medicine 36.1 (2015): 173-185.
Chicago
Huang, C., Yuan, L., Cao, S."Endogenous GLP-1 as a key self-defense molecule against lipotoxicity in pancreatic islets". International Journal of Molecular Medicine 36, no. 1 (2015): 173-185. https://doi.org/10.3892/ijmm.2015.2207