Tyrosine kinase inhibitors prevent cytokine-induced expression of iNOS and COX-2 by human islets.
Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease that is characterized by selective destruction of insulin-secreting beta-cells. Cytokines have been implicated as effector molecules that participate in both islet inflammation and beta-cell destruction during the development of IDDM. In this study, the effects of cytokines on the expression of inducible nitric oxide synthase (iNOS) and inducible cyclooxygenase (COX-2) by human islets were examined. In combination, the cytokines, human recombinant interleukin-1 beta (IL-1 beta), human recombinant tumor necrosis factor-alpha (TNF-alpha), and human recombinant interferon-gamma (IFN-gamma), induce the time-dependent formation of nitrite and prostaglandin E2 (PGE2) by human islets. The nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) completely inhibits cytokine-induced nitrite formation and attenuates PGE2 production by human islets. L-NMMA does not inhibit cytokine-induced expression of COX-2 by human islets, suggesting that nitric oxide may directly activate cyclooxygenase, an effect that has been previously demonstrated for isolated rat islets. This combination of cytokines (IL-1 beta, TNF-alpha, and IFN-gamma) also induces the expression of iNOS mRNA by human islets as demonstrated by both reverse transcriptase-polymerase chain reaction and Northern blot analysis. We further show that the tyrosine kinase inhibitors genistein and herbimycin A prevent IL-1 beta plus IFN-gamma-induced expression of COX-2 and iNOS and the production of PGE2 and nitric oxide by human islets. These results demonstrate that cytokines induce the expression of iNOS and COX-2 by human islets and that cytokine-induced expression of both COX-2 and iNOS by human islets appears to require the activation of a tyrosine kinase(s).
Corbett
J A
JA
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. corbettj@wpogate.slu.edu
Kwon
G
G
Marino
M H
MH
Rodi
C P
CP
Sullivan
P M
PM
Turk
J
J
McDaniel
M L
ML
D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D016227:Benzoquinones; D016861:Cyclooxygenase Inhibitors / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology*; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D007515:Islets of Langerhans / Q000378:metabolism*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007529:Isoflavones / Q000494:pharmacology; D047029:Lactams, Macrocyclic; D015335:Molecular Probes; D008969:Molecular Sequence Data; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011809:Quinones / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019323:omega-N-Methylarginine
D016227:Benzoquinones; D016861:Cyclooxygenase Inhibitors; D016207:Cytokines; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D007527:Isoenzymes; D007529:Isoflavones; D047029:Lactams, Macrocyclic; D015335:Molecular Probes; D011809:Quinones; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D017828:Rifabutin; D019323:omega-N-Methylarginine; C020754:herbimycin; D007371:Interferon-gamma; D001120:Arginine; D019833:Genistein; D019001:Nitric Oxide Synthase; D011505:Protein-Tyrosine Kinases