Intracellular Stress Signaling Pathways Activated During Human Islet Preparation and Following Acute Cytokine Exposure

Intracellular Stress Signaling Pathways Activated During Human Islet Preparation and Following Acute Cytokine Exposure Saida Abdelli 1 , Jeff Ansite 2 , Raphael Roduit 1 , Tiziana Borsello 3 , Ippei Matsumoto 2 , Toshiya Sawada 2 , Nathalie Allaman-Pillet 1 , Hugues Henry 3 , Jacques S. Beckmann 1 , Bernhard J. Hering 2 and Christophe Bonny 1 1 Service of Medical Genetics, Lausanne, Switzerland 2 Diabetes Institute for Immunology and Transplantation, University of Minnesota, Minneapolis, Minnesota 3 University Hospital Falaises, Lausanne, Switzerland Address correspondence and reprint requests to Christophe Bonny, Service of Medical Genetics, 1011 Lausanne-CHUV, Switzerland. E-mail: christophe.bonny{at}chuv.hospvd.ch . Or Bernhard J. Hering, Diabetes Institute for ImmunologyTransplantation, University of Minnesota, 420 Delaware St. SE, Mayo Mailing Code no. 195, Minneapolis, MN 55455. E-mail: bhering{at}tumn.edu Abstract Pancreatic islet transplantation may successfully restore normoglycemia in type 1 diabetic patients. However, successful grafting requires transplantation of a sufficient number of islets, usually requiring two or more donors. During the isolation process and following clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. Here, we have mapped the major intracellular stress-signaling pathways that may mediate human islet loss during isolation and following cytokine attack. We found that the isolation procedure potently recruits two pathways consisting of |mitogen-activated protein kinase kinase (MKK)7 → Jun NH 2 -terminal kinase (JNK)/p38 → c- fos | and the |nuclear factor-κB (NF-κB) → iNOS| module. Cytokines activate the |NF-κB → iNOS| and |MKK4/MKK3/6 → JNK/p38| pathways without recruitment of c- fos . Culturing the islets for 48 h after isolation allows for the activated pathways to return to background levels, with expression of MKK7 becoming undetectable. These data indicate that isolation and cytokines recruit different death pathways. Therefore, strategies might be rationally developed to avoid possible synergistic activation of these pathways in mediating islet loss during isolation and following grafting. DTT, dithiothreitol EMSA, electrophoretic mobility shift assay ERK, extracellular signal–regulated kinase GST, glutathione S-transferase IFNγ, γ-interferon IκB, inhibitor of κB IL-1β, interleukin-1β iNOS, inducible nitric oxide synthase JNK, c-J