Insulin Action/Molecular Metabolism

1692-P Stress in Beta Cells Obtained with Laser Capture Microdissection from Cadaver Pancreases of Brain Dead Donors AREF EBRAHIMI, MIN-HO JUNG, JONATHAN M. DREYFUSS, HUI PAN, DENNIS C. SGROI, SUSAN BONNER-WEIR, GORDON C. WEIR, Boston, MA Brain death of pancreas donors is thought to lead to the expression of infl ammatory, stress and apoptotic pathways in isolated islets resulting in poor clinical outcomes. To test this hypothesis we obtained cadaveric pancreases from brain dead pancreatic donors (n=7, mean age 5011) and normal pancreatic tissue obtained at surgery done for pancreatic neoplasms (n=7, age 699). Frozen sections were subjected to laser capture microdissection to obtain beta-cell rich islet tissue, from which extracted RNA was analyzed with Affymetrix arrays. Gene expression of the two groups was evaluated with principle component analysis (PCA), and differential expression analysis was performed for genes and pathways. The pathways expressed at the highest signifi cance included Glycolysis, Unfolded Protein Response, MTORC1 Signaling, and Pancreatic Beta Cells. Pathways of Apoptosis were not differentially expressed. A striking fi nding was the unfolded protein response (UPR), which is a protective component of the endoplasmic reticulum (ER) stress response that if severe can cause apoptosis. An important group of protective chaperone genes were upregulated in the cadaver donors (HSP90B1, HSPA5, PDIA6, DnaJB9 and DnaJC3). In addition the protective genes of ER-associated protein degradation (ERAD) proteins (DERL 1, 2, 3) were upregulated. In contrast the proapoptotic “executioner” genes CHOP and JNK were not upregulated. Other evidence of stress included upregulation of genes associated with NFkB activation and TNF pathways, including TNFRSF1A, IL17RB and IL13RA1. Other upregulated genes of interest included REG1B, LDHA and Tissue Factor. In conclusion, while there was little evidence of active apoptosis in beta cells from cadaver donors, stress markers were found that could represent vulnerability resulting from brain death and/or the trauma of organ preservation. This could account for some of the early beta cell death found with islet transplantation. Supported By: National Institutes of Health