Two-dimensional gel electrophoresis of rat islet proteins. Interleukin 1 beta-induced changes in protein expression are reduced by L-arginine depletion and nicotinamide.
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.
Andersen
H U
HU
Steno Diabetes Center, Gentofte, Denmark.
Larsen
P M
PM
Fey
S J
SJ
Karlsen
A E
AE
Mandrup-Poulsen
T
T
Nerup
J
J
D000818:Animals; D001120:Arginine / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D007375:Interleukin-1 / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000737:chemistry*; D007526:Isoelectric Point; D008970:Molecular Weight; D009536:Niacinamide / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D011247:Pregnancy; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D007375:Interleukin-1; D011506:Proteins; D009536:Niacinamide; D009569:Nitric Oxide; D001120:Arginine