Proteomics Analysis of Cytokine-induced Dysfunction and Death in Insulin-producing INS-1E Cells

• Published in: Molecular & cellular proteomics Vol. 6; no. 12; pp. 2180 - 2199
• Main Authors: D'Hertog, Wannes, Overbergh, Lut, Lage, Kasper, Ferreira, Gabriela Bonfim, Maris, Michael, Gysemans, Conny, Flamez, Daisy, Cardozo, Alessandra Kupper, Van den Bergh, Gert, Schoofs, Liliane, Arckens, Lut, Moreau, Yves, Hansen, Daniel Aaen, Eizirik, Decio Laks, Waelkens, Ettienne, Mathieu, Chantal
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.2007; American Society for Biochemistry and Molecular Biology
• ISSN: 1535-9476; 1535-9484
• DOI: 10.1074/mcp.M700085-MCP200

Cytokines released by islet-infiltrating immune cells play a crucial role in β-cell dysfunction and apoptotic cell death in the pathogenesis of type 1 diabetes and after islet transplantation. RNA studies revealed complex pathways of genes being activated or suppressed during this β-cell attack. The aim of the present study was to analyze protein changes in insulin-producing INS-1E cells exposed to inflammatory cytokines in vitro using two-dimensional DIGE. Within two different pH ranges we observed 2214 ± 164 (pH 4–7) and 1641 ± 73 (pH 6–9) spots. Analysis at three different time points (1, 4, and 24 h of cytokine exposure) revealed that the major changes were taking place only after 24 h. At this time point 158 proteins were altered in expression (4.1%, n = 4, p ≤ 0.01) by a combination of interleukin-1β and interferon-γ, whereas only 42 and 23 proteins were altered by either of the cytokines alone, giving rise to 199 distinct differentially expressed spots. Identification of 141 of these by MALDI-TOF/TOF revealed proteins playing a role in insulin secretion, cytoskeleton organization, and protein and RNA metabolism as well as proteins associated with endoplasmic reticulum and oxidative stress/defense. We investigated the interactions of these proteins and discovered a significant interaction network (p < 1.27e−05) containing 42 of the identified proteins. This network analysis suggests that proteins of different pathways act coordinately in a β-cell dysfunction/apoptotic β-cell death interactome. In addition the data suggest a central role for chaperones and proteins playing a role in RNA metabolism. As many of these identified proteins are regulated at the protein level or undergo post-translational modifications, a proteomics approach, as performed in this study, is required to provide adequate insight into the mechanisms leading to β-cell dysfunction and apoptosis. The present findings may open new avenues for the understanding and prevention of β-cell loss in type 1 diabetes.