Diabetes, Vol 44, Issue 4 400-407, Copyright © 1995 by American Diabetes Association
Two-dimensional gel electrophoresis of rat islet proteins. Interleukin 1 beta-induced changes in protein expression are reduced by L-arginine depletion and nicotinamide
HU Andersen, PM Larsen, SJ Fey, AE Karlsen, T Mandrup-Poulsen and J Nerup
Steno Diabetes Center, Gentofte, Denmark.
Interleukin (IL)-1 beta-mediated damage to beta-cells in isolated islets of
Langerhans depends upon de novo synthesis of proteins that have not been
fully identified. Further, IL-1 beta-induced and tumor necrosis factor
alpha-induced islet damage partly depends on the intracellular production
of the nitric oxide (NO) radical. IL-1 beta has also been reported to
induce the synthesis of cellular defense proteins, e.g., heme-oxygenase and
heat shock proteins 70 and 90. Nicotinamide, while in itself inactive,
inhibited IL-1 beta-induced NO production in a time- and dose-dependent
manner. To enable the identification of IL-1 beta-induced proteins with
possible protective and deleterious effects, we characterized the effects
of IL-1 beta, nicotinamide, and NO synthesis inhibition by L-arginine
depletion on rat islet protein expression detected by high-resolution
two-dimensional gel electrophoresis. More than 1,600 proteins were
reproducibly detected in control rat islets. Incubation with IL-1 beta-,
nicotinamide-, or L-arginine-depleted control medium upregulated 29, 3, and
1 protein, respectively, and downregulated 4, 0, and 1 protein,
respectively. Addition of nicotinamide and L-arginine depletion reduced the
upregulation of 16 and 20 IL-1 beta-induced proteins, respectively. The
identity of these proteins is under study. The demonstrated changes in
protein expression caused by IL-1 beta +/- nicotinamide and L-arginine
depletion may form the basis for identification of proteins with possible
protective and deleterious roles in the initial beta-cell destruction in
insulin-dependent diabetes mellitus.