Interleukin-1 beta, Src- and non-Src tyrosine kinases, and nitric oxide synthase induction in rat aorta in vitro

We studied the potential roles for endogenous interleukin-1 beta (IL-1 beta ) and for several signaling pathways in the spontaneous induction in vitro of inducible nitric oxide synthase (iNOS) in endothelium-denuded rat aorta rings. Added IL-1 beta augmented, whereas the IL-1 beta receptor antagonist IL-1ra blocked, spontaneous iNOS induction. Furthermore, increases in IL-1 beta mRNA preceded those of iNOS mRNA. Mitogen-activated protein kinase ki nase and phosphatidyl inositol 3' kinase inhibition did not block iNOS indu ction, whereas nuclear factor kappa B inhibition did. The sarcoma virus tyr osine kinase (Src) family-selective inhibitor 4-amino-5(4-methylphenyl)-7-( t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) blocked the upregulation of IL-1 be ta mRNA and the subsequent induction of iNOS but not the induction of iNOS stimulated by exogenously added IL-1 beta. In contrast, the non-Src inhibit ors TP 47/AG 213 and genistein and the tyrosine phosphatase inhibitor vanad ate did not affect the spontaneous upregulation of IL-1 beta mRNA but block ed both the IL-1 beta-mediated and spontaneous induction of iNOS. We conclu de that 1) the upregulation of tissue IL-1 beta, via a signaling pathway in volving a Src family kinase, plays a key role in rat vascular iNOS inductio n and 2) non-Src tyrosine kinases play roles downstream from IL-1 beta for iNOS induction.