title: Dysfunctional CFTR alters the bactericidal activity of human macrophages against Pseudomonas aeruginosa.
abstract: Chronic inflammation of the lung, as a consequence of persistent bacterial infections by several opportunistic pathogens represents the main cause of mortality and morbidity in cystic fibrosis (CF) patients. Mechanisms leading to increased susceptibility to bacterial infections in CF are not completely known, although the involvement of cystic fibrosis transmembrane conductance regulator (CFTR) in microbicidal functions of macrophages is emerging. Tissue macrophages differentiate in situ from infiltrating monocytes, additionally, mature macrophages from different tissues, although having a number of common activities, exhibit variation in some molecular and cellular functions. In order to highlight possible intrinsic macrophage defects due to CFTR dysfunction, we have focused our attention on in vitro differentiated macrophages from human peripheral blood monocytes. Here we report on the contribution of CFTR in the bactericidal activity against Pseudomonas aeruginosa of monocyte derived human macrophages. At first, by real time PCR, immunofluorescence and patch clamp recordings we demonstrated that CFTR is expressed and is mainly localized to surface plasma membranes of human monocyte derived macrophages (MDM) where it acts as a cAMP-dependent chloride channel. Next, we evaluated the bactericidal activity of P. aeruginosa infected macrophages from healthy donors and CF patients by antibiotic protection assays. Our results demonstrate that control and CF macrophages do not differ in the phagocytic activity when infected with P. aeruginosa. Rather, although a reduction of intracellular live bacteria was detected in both non-CF and CF cells, the percentage of surviving bacteria was significantly higher in CF cells. These findings further support the role of CFTR in the fundamental functions of innate immune cells including eradication of bacterial infections by macrophages.
authors.affiliation: Department of Biology and Biotechnology Charles Darwin, Sapienza University, Rome, Italy. delporto@uniroma1.it
authors.forename: Paola
authors.initials: P
authors.lastname: Del Porto
authors.forename: Noemi
authors.initials: N
authors.lastname: Cifani
authors.forename: Simone
authors.initials: S
authors.lastname: Guarnieri
authors.forename: Enea Gino
authors.initials: EG
authors.lastname: Di Domenico
authors.forename: Maria A
authors.initials: MA
authors.lastname: Mariggiò
authors.forename: Francesca
authors.initials: F
authors.lastname: Spadaro
authors.forename: Silvia
authors.initials: S
authors.lastname: Guglietta
authors.forename: Marco
authors.initials: M
authors.lastname: Anile
authors.forename: Federico
authors.initials: F
authors.lastname: Venuta
authors.forename: Serena
authors.initials: S
authors.lastname: Quattrucci
authors.forename: Fiorentina
authors.initials: F
authors.lastname: Ascenzioni
mesh_terms: D000293:Adolescent; D000328:Adult; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000502:physiology*; D005260:Female; D006801:Humans; D008264:Macrophages / Q000276:immunology*; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D011550:Pseudomonas aeruginosa / Q000276:immunology*
chemical_list: D019005:Cystic Fibrosis Transmembrane Conductance Regulator