title: Anti-inflammatory properties of exenatide in human pancreatic islets.
abstract: Exenatide is an analog of the incretin hormone glucagon-like peptide (GLP-1) that is used for the treatment of T2D for their metabolic effects. In addition to its insulinotropic effects, exenatide increases functional islet mass and improves their survival. Improved outcomes have been  reported in recent clinical islet transplantation trials for the treatment of type 1 diabetes. The purpose of this study was to investigate whether exenatide has anti-inflammatory properties in human islets. Exenatide treatment improved islet function, significantly reduced content of inflammation-related  molecules (tissue factor, IFN-γ, IL-17, IL-1β, and IL-2) and caspase 3 activation, whereas increased phosphorylation of ERK1/2, STAT3, and Akt in vitro. Immunostaining showed expression of GLP-1R in β-cells but not in α-cells. IL-1β colocalized with GLP-1R in β-cells.  Induction of serine proteinase inhibitor 9 (PI-9) was detected after exposure of human islets to exenatide in vitro and after transplantation into immunodeficient mice. GLP-1 induced PI-9 expression in vitro but to a lower extent than exenatide. This effect was partially blocked by the antagonist  exendin-9 in vitro. As assessed by immunostaining PI-9 is mostly expressed in β-cells but not in α-cells. In conclusion, we describe anti-inflammatory and cytoprotective properties of exenatide in human islets. Exenatide-mediated PI-9 expression, the only known granzyme B inhibitor,  unveils potential immunoregulatory properties.
authors.affiliation: Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Cechin
authors.forename: I
authors.initials: I
authors.lastname: Pérez-Álvarez
authors.forename: E
authors.initials: E
authors.lastname: Fenjves
authors.forename: R D
authors.initials: RD
authors.lastname: Molano
authors.forename: A
authors.initials: A
authors.lastname: Pileggi
authors.forename: P-O
authors.initials: PO
authors.lastname: Berggren
authors.forename: C
authors.initials: C
authors.lastname: Ricordi
authors.forename: R L
authors.initials: RL
authors.lastname: Pastori
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D010455:Peptides / Q000494:pharmacology*; D014688:Venoms / Q000494:pharmacology*
chemical_list: D000893:Anti-Inflammatory Agents; D020381:Interleukin-17; D007376:Interleukin-2; D010455:Peptides; D014688:Venoms; D007371:Interferon-gamma; D052216:Glucagon-Like Peptide 1; D000077270:Exenatide; D053148:Caspase 3