Abstract
Purpose
Group X (GX) and group V (GV) secretory phospholipase A2 (sPLA2) potently release arachidonic acid (AA) from the plasma membrane of intact cells. We previously demonstrated that GX sPLA2 negatively regulates glucose-stimulated insulin secretion (GSIS) by a prostaglandin E2 (PGE2)-dependent mechanism. In this study we investigated whether GV sPLA2 similarly regulates GSIS.
Methods
GSIS and pancreatic islet-size were assessed in wild-type (WT) and GV sPLA2-knock out (GV KO) mice. GSIS was also assessed ex vivo in isolated islets and in vitro using MIN6 pancreatic beta cell lines with or without GV sPLA2 overexpression or silencing.
Results
GSIS was significantly decreased in islets isolated from GV KO mice compared to WT mice and in MIN6 cells with siRNA-mediated GV sPLA2 suppression. MIN6 cells overexpressing GV sPLA2 (MIN6-GV) showed a significant increase in GSIS compared to control cells. Though the amount of AA released into the media by MIN6-GV cells was significantly higher, PGE2 production was not enhanced or cAMP content decreased compared to control MIN6 cells. Surprisingly, GV KO mice exhibited a significant increase in plasma insulin levels following i.p. injection of glucose compared to WT mice. This increase in GSIS in GV KO mice was associated with a significant increase in pancreatic islet size and number of proliferating cells in β-islets compared to WT mice.
Conclusions
Deficiency of GV sPLA2 results in diminished GSIS in isolated pancreatic beta-cells. However, the reduced GSIS in islets lacking GV sPLA2 appears to be compensated by increased islet mass in GV KO mice.
Document Type
Article
Publication Date
10-2017
Digital Object Identifier (DOI)
https://doi.org/10.1007/s12020-017-1379-1
Funding Information
This work was supported in whole or in part by National Institutes of Health Grant R01 DK082419 (to N. R. W.) and the NIGMS Grant P20 GM103527 (to P. S.).
Repository Citation
Shridas, Preetha; Noffsinger, Victoria P.; Trumbauer, Andrea C.; and Webb, Nancy R., "The Dual Role of Group V Secretory Phospholipase A2 in Pancreatic β-Cells" (2017). Saha Cardiovascular Research Center Faculty Publications. 39.
https://uknowledge.uky.edu/cvrc_facpub/39
Included in
Cardiology Commons, Circulatory and Respiratory Physiology Commons, Endocrinology, Diabetes, and Metabolism Commons
Notes/Citation Information
Published in Endocrine, v. 58, issue 1, p. 47-58.
© Springer Science+Business Media, LLC 2017
The copyright holder has granted the permission for posting the article here.
This is a post-peer-review, pre-copyedit version of an article published in Endocrine. The final authenticated version is available online at: https://doi.org/10.1007/s12020-017-1379-1