The effect of the decoy molecule PA401 on CXCL8 levels in bronchoalveolar lavage fluid of patients with cystic fibrosis

PA401 reduces levels of CXCL8 in cystic fibrosis airway samples thereby reducing neutrophil migration. (A) The chemokine CXCL8 is a key mediator of inflammation in patients with CF and increases neutrophil migration to the airways. Glycosaminoglycans (GAGs) possess the ability to influence the chemokine profile of the CF lung by binding CXCL8 and protecting it from proteolytic degradation. (B) As the CXCL8 decoy PA401 lacks chemotactic activity yet demonstrates increased glycan binding affinity it functions to disrupt CXCL8:GAG complexes, rendering the chemokine susceptible to proteolytic degradation. Clinical application of PA401 or similar CXCL8 decoy molecules, may serve to decrease the inflammatory burden in the CF lung in vivo. •In individuals with cystic fibrosis CXCL8 is a key mediator of inflammation.•The CXCL8 decoy PA401 decreases CXCL8 levels in cystic fibrosis airway secretions.•Mechanism of action involves disruption of glycosaminoglycan: CXCL8 complexes.•Outcome is reduced neutrophil chemotaxis consistent with resolution of inflammation. The chemokine interleukin-8 (CXCL8) is a key mediator of inflammation in airways of patients with cystic fibrosis (CF). Glycosaminoglycans (GAGs) possess the ability to influence the chemokine profile of the CF lung by binding CXCL8 and protecting it from proteolytic degradation. CXCL8 is maintained in an active state by this glycan interaction thus increasing infiltration of immune cells such as neutrophils into the lungs. As the CXCL8-based decoy PA401 displays no chemotactic activity, yet demonstrates glycan binding affinity, the aim of this study was to investigate the anti-inflammatory effect of PA401 on CXCL8 levels, and activity, in CF airway samples in vitro. Bronchoalveolar lavage fluid (BALF) was collected from patients with CF homozygous for the ΔF508 mutation (n=13). CXCL8 in CF BALF pre and post exposure to PA401 was quantified by ELISA. Western blot analysis was used to determine PA401 degradation in CF BALF. The ex vivo chemotactic activity of purified neutrophils in response to CF airway secretions was evaluated post exposure to PA401 by use of a Boyden chamber-based motility assay. Exposure of CF BALF to increasing concentrations of PA401 (50–1000pg/ml) over a time course of 2–12h in vitro, significantly reduced the level of detectable CXCL8 (P