Uticaj interleukina-17 na produkciju azot monoksida (NO) od strane L929 ćelijske linije mišijih fibroblasta
Effect of interleukin-17 on nitric oxide production in murine fibroblast-like cell line L929
Trajković, Vladimir S.
Samardžić, Tatjana S.
Article (Published version)
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The ability of interleukin-17 (IL-17) to induce nitric oxide (NO) synthesis in murine L929 fibroblasts was investigated. L929 cells were incubated with IL-17 and/or LPS, interferon-g (IFN-gama), interleukin-1 (IL-1), or dibutyryl-cAMP. NO production was assessed indirectly, by measuring nitrite accumulation in 24 h culture supernatants. L929 fibroblasts did not produce NO constitutively, nor IL-17 alone induced NO production. Of all other stimuli tested, only IFN-gama significantly up regulated nitrite level in L929 cell cultures. However, when IL-17 was applied simultaneously with each of the tested stimuli, NO synthesis was markedly elevated, thus indicating involvement of distinct signaling pathways of NO induction by IL-17 and other tested agents. Production of NO by IL-17+LPS-treated L929 cells was dependent on synthesis and activity of inducible NO synthase (iNOS), as indicated by abrogation of nitrite accumulation with protein synthesis inhibitor cycloheximide or selective inhibitor of iNOS, aminoguanidine. A role for protein tyrosine kinase (PTK) and transcription factor NF-kB in iNOS activation is suggested by reduction of NO synthesis with PTK inhibitor genistein and an inhibitor of NF-kB activation, pyrrolidine dithiocarbamate (PDTC). In contrast, protein kinase C inhibitor staurosporine was ineffective in blocking IL-17+LPS-induced NO production in L929 cells. Taken together, our results for the first time showed an active participation of IL-17 in co-induction of fibroblast NO synthesis with LPS, cytokines (IL-1, IFN-gama), or cAMP analogue, and suggested that IL-17 up-regulated NO synthesis in fibroblasts through mechanisms involving PTK and NF-kB activation.