title: Neutrophil enhancement of Pseudomonas aeruginosa biofilm development: human F-actin and DNA as targets for therapy.
abstract: In the cystic fibrosis (CF) airway, chronic infection by Pseudomonas aeruginosa results from biofilm formation in a neutrophil-rich environment. We tested the capacity of human neutrophils to modify early biofilm formation of P. aeruginosa strain PAO1, and an isogenic CF strain isolated early and years later in infection. In a static reactor, P. aeruginosa biofilm density of all strains was enhanced at 24 h in the presence of neutrophils, with the greatest relative increase associated with the lowest inoculum of P. aeruginosa tested. Previously, neutrophil-induced biofilm enhancement was shown to largely result from the incorporation of F-actin and DNA polymers into the bacterial biofilm. This finding was advanced by the comparison of biofilm enhancement from intact unstimulated neutrophils and from lysed or apoptotic neutrophils. Apoptotic neutrophils, with an intact cell membrane, were unable to contribute to biofilm enhancement, while lysed neutrophils evoked a similar response to that of intact cells. Using F-actin and DNA as targets, the capacity of negatively charged poly(amino acids) to disrupt, or prevent, early biofilm formation was tested. Anionic poly(aspartic acid) effectively prevented or disrupted biofilm formation. Combination of poly(aspartic acid) with DNase resulted in a synergistic increase in biofilm disruption. These results demonstrate that the presence of dying neutrophils can facilitate the initial stages of biofilm development by low inocula of P. aeruginosa. Neutrophil F-actin represents a potential new therapeutic target for disruption of pathogenic biofilms.
authors.affiliation: Department of Medicine, National Jewish Health, 1400 Jackson, Denver, CO, USA.
authors.forename: Quinn M
authors.initials: QM
authors.lastname: Parks
authors.affiliation: Division of Pulmonary Science and Critical Care Medicine, University of Colorado, 4200 E. 9th Ave, Denver, CO, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Young
authors.affiliation: Department of Medicine, National Jewish Health, 1400 Jackson, Denver, CO, USA.
authors.forename: Katie R
authors.initials: KR
authors.lastname: Poch
authors.affiliation: Department of Medicine, National Jewish Health, 1400 Jackson, Denver, CO, USA.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Malcolm
authors.affiliation: Department of Microbiology, University of Colorado Denver Anschutz Medical Campus, 12800 E. 19th Ave, Aurora, CO, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Vasil
authors.affiliation: Division of Pulmonary Science and Critical Care Medicine, University of Colorado, 4200 E. 9th Ave, Denver, CO, USA.|Department of Medicine, National Jewish Health, 1400 Jackson, Denver, CO, USA.
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Nick
mesh_terms: D000199:Actins / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002939:Ciprofloxacin / Q000494:pharmacology; D004247:DNA / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000494:pharmacology; D006801:Humans; D009504:Neutrophils / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000199:Actins; D000900:Anti-Bacterial Agents; D010455:Peptides; C017645:polyaspartate; D002939:Ciprofloxacin; D004247:DNA; D003851:Deoxyribonucleases; D014031:Tobramycin