Sustained inhibition of IL‐6 and IL‐8 expression by decoy ODN to NF‐κB delivered through respirable large porous particles in LPS‐stimulated cystic fibrosis bronchial cells

Abstract

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Neutrophil-dominated inflammation and chronic bacterial infection are still considered the primary cause of bronchioectasis, respiratory failure and consequent death in CF patients. Activation of nuclear factor (NF)-κB is responsible for overproduction of cytokines, such as interleukin (IL)-6 and IL-8, in airways of CF patients. Thus, decoy oligodeoxynucleotides against NF-κB (dec-ODN) may limit lung inflammation in CF. In the present study, we studied the effects of dec-ODN delivered through biodegradable and respirable poly(D,L-lactide-co-glycolide) large porous particles (LPP) on IL-6 and IL-8 mRNA expression as well as NF-κB/DNA binding activity in cystic fibrosis cells stimulated with lipopolysaccharide (LPS) from Pseudomonas aeruginosa. dec-ODN LPP were prepared by a modified double emulsion technique and characterized in terms of size, morphology, tapped density and dec-ODN loading. Human epithelial bronchial IB3-1 (CFTR-mutated) as well as S9 (CFTR-corrected) were stimulated with LPS from P. aeruginosa for 24 and 72 h in the absence or presence of naked dec-ODN or dec-ODN LPP. Stimulation of cells with LPS from P. aeruginosa caused an increase of IL-6 and IL-8 mRNA levels, which were significantly inhibited by dec-ODN LPP at 24 and 72 h, whereas naked dec-ODN inhibited those only at 24 h. Similar effects were exhibited by dec-ODN LPP or naked dec-ODN on NF-κB/DNA binding activity. Our observations indicate that respirable biodegradable dec-ODN LPP may represent a promising strategy for inhibiting NF-κB transcriptional activity and related gene expression and, thus, reduce lung chronic inflammation in CF patients.