Islets transplantation group, Institute for Surgical Research
Oslo University Hospital
Glial Cell-derived Neurotrophic Factor protects human islets from apoptosis induced by serum starvation and endoplasmic reticulum stress through PI3K/AKT signaling pathway
Shadab Abadpour1,2, Sven Gopel3, Aksel Foss1,2, Hanne Scholz1,2.
1Section for Transplantation, Institute for Surgical Research, Oslo University Hospital, Oslo, Norway; 2Institute of Clinical Medicine, University of Oslo , Oslo, Norway; 3AstraZeneca R&D, Molndal, Sweden
Introduction: One of the most promising new treatments for patients with type 1- diabetes is islets transplantation. However, a widespread application of procedure is hindered by different obstacles such as high rate of cell apoptosis during islets isolation and pre-transplant culture. Therefore, we have investigated whether Glial Cell-derived Neurotrophic Factor (GDNF) can eliminate serum starvation-induced apoptosis and endoplasmic reticulum stress-induced cell death in human islets in vitro.
Methods: Human islets isolated from male and female deceased donors, age between 20-70 years old. Subsequently, equal numbers of human islets were cultured in CMRL-1066 medium supplemented with 0.5% AB serum, in order to mimic starvation condition, and treated with or without GDNF (200 ng/ml) for 72 hours. In parallel, and with the aim of studying protective effect of GDNF against ER stress-induced apoptosis, human islets were exposed to Thapsigargin (Tg) (1uM) with or without GDNF (200 ng/ml) for 48 hours. Islets function was assessed by analyzing glucose stimulated insulin secretion presented as stimulation index (SI) and apoptosis was detected by using Cell Death ELISA. Phosphorylation of PI3K, AKT and GSK3β in human islets were analyzed by Bioplex assay and the ER stress mediator CHOP by Western blot.
Results: GDNF improve stimulation index (n=7, p<0.01 vs control) and reduce apoptosis (n=7, p<0.0001 vs control) in serum-starved human islets. In addition, Tg significantly elevated human islets apoptosis (n=6, p<0.0001 vs control) whereas GDNF were able to rescue islets by decreasing apoptosis (n=6, p<0.01 vs Tg-treated islets). Western blot/Bioplex analysis revealed that ER stress in human islets treated with GDNF leads to reduce expression of Chop, whereas the signaling pathway p-PI3K, p-AKT and p-GSK3β was increased (n=3, p<0.05 vs Tg-treated islets)
Conclusions: GDNF protects human islets against endoplasmic reticulum stress in vitro through PI3K/p-AKT/p-GSK3β signaling pathway. Supplementation of human islet culture medium with GDNF could be one strategy to improve islet survival prior to transplantation.
07:00 - 08:00
|Mini-Orals: Experimental islet transplantation||Glial Cell-derived Neurotrophic Factor protects human islets from apoptosis induced by serum starvation and endoplasmic reticulum stress through PI3K/AKT signaling pathway||Room 110|
17:30 - 18:30
|Joint Poster Session||The effect of high glucose on expression of Thioredoxin-interacting protein and Interluekin-22 on human islets survival and function in vitro and in vivo||Main Foyer 1 & 2|