49 Reduction of tumor necrosis factor alpha (TNFα) expression by azithromycin (AZM) in CF airway epithelial cells

Abstract

AZM has been described to ameliorate airway inflammation in CF patients. We aimed to study properties of this macrolide relevant for therapy, in particular antiinflammatory effects. Since TNFo. plays a relevant role in pathogenesis o f CF as pro-inflammatory molecule, we compared its levels of mRNA and protein expression, by QPCR and ELISA, in two CF airway epithelial cell lines. Cells were incubated with AZM or josamycin (JM), a macrolide lacking clinical anti-inflammatory effects. Activation o f pro-inflammatory transcription factors (TF) involved in the regulation of TNFo. transcription as Nuclear Factor-kB (NF-kB) and Specificity protein 1 (Spl) was determined by immunofluorescent staining in untreated cells and in the presence of AZM. We found that AZM reduces the levels of TNFo. mRNA in both cell lines (about 30%, p < 0.01) as well as TNFo. protein levels (about 55%, p < 0.01) compared to untreated cells, while JM was not significantly effective. Nuclear staining of NFkB and Spl was reduced in the presence of AZM in comparison with untreated cells. In an isogenic non-CF cell line we detected statistically significantly lower levels of TNFo. compared to the CF line, specifically supporting the therapeutic relevance of our data. Our study demonstrates that AZM reduces the expression of TNFo. mRNA and protein and suggests the inhibition of nuclear localization of NF-kB and Spl as a possible mechanism. Consistent with our previous detection of inhibition of interleukin 8 expression by AZM, the results of the present study further support the proposed anti-inflammatory effects of this macrolide relevant for therapy o f CE Supported by Italian Cystic Fibrosis Research Foundation (FFC10/05) and Legge 548/93 Finanziamento Ricerca Fibrosi Cistica 2004. 3. New therapies'