CFTR is required for mediation of pro/anti-inflammatory balance by vardenafil in CF mouse macrophages

CFTR is required for mediation of pro/anti-inflammatory balance by vardenafil in mouse CF macrophages Barbara Dhooghe, Sabrina Noel, Francois Huaux, Nadtha Panin, Teresinha Leal LTAP, IREC, Universite catholique de Louvain, Brussels, Belgium Lung inflammation is a key feature of cystic fibrosis. Promising anti-inflammatory properties have been reported for vardenafil, a phosphodiesterase type 5 inhibitor (iPDE5). We have recently demonstrated that it reduces LPS-induced inflammatory responses in CF mice (Lubamba et al., 2012). We hypothesized that CF macrophages are characterized by a proinflammatory phenotype which can be modulated by vardenafil. Moreover, we want to examine a possible role of CFTR in vardenafil-induced immunomodulation of macrophages. Macrophages were isolated and purified from lung homogenates from homozygous F508del-CFTR, CFTR-/- (KO) and wild-type (WT) mice. To test the hypothesis that the activity of macrophages is altered in F508del-CF and KO mice, macrophages differentiation in pro-inflammatory (M1) effectors was studied after polarization with LPS and IFN-γ. Pro-inflammatory mediators TNF-α and NOS-2 were quantified by ELISA (in culture supernatants) or by quantitative RT-PCR (in cultured macrophages). In each condition, the effect of vardenafil (10-50µM) was evaluated. F508del-CF lung macrophages displayed an exaggerated pro-inflammatory response to M1 mediators. Both TNF-α and NOS-2 levels were more than doubled. Similar observations were made in macrophages isolated from KO mice, confirming that loss of CFTR promotes proinflammatory phenotype in macrophages. In F508del-CF mice, vardenafil reduced the expression of pro-inflammatory mediators by at least 50%. However, vardenafil failed to normalize TNF-α and NOS-2 expression in KO macrophages, suggesting that the presence of CFTR protein is required for immunomodulation by vardenafil. Taken together, our results indicate that macrophages display a pro-inflammatory profile and play a critical role in inflammatory responses in CF. Moreover, the immunomodulatory effect of vardenafil, which could thus be beneficial in CF pharmacotherapy, requires CFTR expression. Lubamba, B., Huaux, F., Lebacq, J., Marbaix, E., Dhooghe, B., Panin, N., Wallemacq, P., and Leal, T. (2012). Immunomodulatory activity of vardenafil on induced lung inflammation in cystic fibrosis mice. Journal of Cystic Fibrosis 11, 266-273.