Modulation of inducible nitric oxide synthase in RINm5F cells.
The rat insulinoma beta-cell line RINm5F, which shares some homology with pancreatic islets, was used to study nitric oxide synthase induction. Nitric oxide is involved during beta-cell destruction and possibly in propagation of insulin-dependent diabetes mellitus. The cytokine interleukin-1 (IL-1) turned out to be the ultimate inducer, whereas tumour necrosis factor-alpha (TNF) and unexpectedly the phorbol ester TPA (12-O-tetradecanoylphorbol-13-acetate; 10 nM) synergistically promoted nitrite accumulation. Besides employing TPA directly, the synergistic effect of TNF could be traced back to protein kinase C activation since protein kinase C inhibitors (IC50 value for staurosporine: 4 nM) potently suppressed nitrite production in the case of IL-1/TNF administration. Further experiments using anti-TNF antibodies aimed to an autocrine loop following IL-1 addition to RINm5F cells, possibly involved in nitrite generation. Moreover, the nitric oxide synthase inductive IL-1 signal was antagonized by lipophilic cAMP analogues. Our results for nitrite accumulation in RINm5F cells point to activating protein kinase C and inhibitory protein kinase A signalling pathways.
Messmer
U K
UK
University of Konstanz, Faculty of Biology, Germany.
Brüne
B
B
D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis*; D000818:Animals; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004357:Drug Synergism; D004790:Enzyme Induction; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase; D009573:Nitrites / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D009573:Nitrites; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate