Vardenafil reduces macrophage pro-inflammatory overresponses in cystic fibrosis through PDE5- and CFTR-dependent mechanisms

Chronic inflammation that progressively disrupts the lung tissue is a hallmark of cystic fibrosis (CF). In mice, vardenafil, an inhibitor of phosphodiesterase type 5 (PDE5), restores transepithelial ion transport and corrects mislocalization of the most common CF mutation, F508del-CFTR. It also reduces lung pro-inflammatory responses in mice and in patients with CF. To test the hypothesis that macrophages are target effector cells of the immunomo-dulatory effect of vardenafil, we isolated lung macrophages from mice homozygous for the F508del mutation or invalidated for the cftr gene and from their corresponding wild-type (WT) littermates. We then evaluated the effect of vardenafil on the classical M1 polarization, mirroring release of pro-inflammatory cytokines. We confirmed that macrophages from different body compartments express CF transmembrane conductance regulator (CFTR) and showed that vardenafil targets the cells through PDE5- and CFTR-dependent mechanisms. In the presence of the F508del mutation, vardenafil down-regulated overresponses of the M1 markers, tumour necrosis factor (TNF)-α and inducible nitric oxide synthase (NOS)-2. Our study identifies lung macrophages as target cells of the anti-inflammatory effect of vardenafil in CF and supports the view that the drug is potentially beneficial for treating CF as it combines rescue of CFTR protein and anti-inflammatory properties. * cAMP, : cyclic adenosine monophosphate; BAL, : bronchoalveolar lavage; CD, : cluster of differentiation; CF, : cystic fibrosis; CFTR, : CF transmembrane conductance regulator; DMEM, : Dulbecco's modified Eagle's medium; FACS, : fluorescence-activated cell sorting; cGMP, : cyclic guanosine monophosphate; LPS, : lipopolysaccharide bacterial endotoxin; MACS, : magnetic-activated cell sorting; NOS-2, : nitric oxide synthase 2 (inducible); PDE, : phosphodiesterase; PL, : peritoneal lavage; SDS–PAGE, : sodium dodecyl sulfate-polyacrylamide gel electrophoresis; siRNA, : small interfering RNA; TNF-α, : tumour necrosis factor-α; WT, : wild-type