Protection of human respiratory epithelium from Pseudomonas aeruginosa adherence by phosphatidylglycerol liposomes

Abstract

The ability of phosphatidylglycerol (DSPG) liposomes to prevent adherence of Pseudomonas aeruginosa to primary cultures of non-cystic fibrosis (CF) and AF508 homozygous CF human respiratory epithelium was studied. The culture model was characterized by the simultaneous presence of various cellular phenotypes: well-differentiated respiratory epithelial cells, ciliated and nonciliated cells, and migrating cells which can be assimilated into a regenerating epithelium after injury. DSPG liposomes significantly decreased the binding of P. aeruginosa to migrating cells of both non-CF and AF508 homozygous CF cultures compared with control cultures (35.5 x 10-3 ± 8.1 X 10-3 bacteria per tLm2 versus 23.9 x 10-3 ± 2.5 X 10-3; P < 0.01 for non-CF cultures and 88.8 X 10-± 17.2 X i03 bacteria per jim2 versus 29.1 X ±0-± 0.6 X 10-, P < 0.001 for CF cultures). After treatment with DSPG liposomes, the size of P. aeruginosa aggregates bound to migrating cells in both non-CF cultures and AF508 homozygous CF cultures was significantly decreased (14.4 ± 3 bacteria per aggregate versus 11.9 ± 2.5 bacteria per aggregate [P < 0.05] and 29.9 ± 8.4 bacteria per aggregate versus 17.3 ± 2.3 bacteria per aggregate [P < 0.011, respectively). Moreover, the control cultures were characterized by a differential P. aeruginosa adherence according to both the cellular phenotype and the mutation. The migrating cells bound more bacteria than the stationary cells of both non-CF and AF508 homozygous CF cultures. The CF migrating cells bound significantly more bacteria than the non-CF migrating cells (88.8 x i0-3 ± 17.2 X i03 bacteria per jim2 versus 35.5 X i0-3 ± 8.1 X i0-3 bacteria per jim2, P < 0.001). These results suggest that DSPG liposomes are able to decrease P. aeruginosa adherence to CF and non-CF respiratory epithelium, particularly to migrating cells, which mimic a regenerating epithelium after injury. DSPG liposomes could also represent a hydrophobic barrier limiting the deleterious action of P. aeruginosa exoproducts.

Asialo GM1 is a receptor for Pseudomonas aeruginosa adherence to regenerating respiratory epithelial cells

“…During spreading, which is the first event of epithelial regeneration, CF and non-CF respiratory epithelial cells bind a great number of P. aeruginosa organisms, with significantly greater bacterial adherence in CF cells than in non-CF cells. These results are in agreement with our previous data (8) and with the results of Zar et al (28), who suggested that the CFTR gene mutation leading to CFTR FIG. 3.…”

“…The major bacterial adhesins implicated in epithelial adherence are pili (23). We and others have reported elsewhere (8,17,18) the unique tropism of P. aeruginosa for regenerating respiratory epithelial cells characterized by a spreading shape, which was previously identified during respiratory epithelial wound repair after injury (27). Following denudation of the extracellular matrix, the respiratory epithelium is rapidly able to regenerate.…”

“…Epithelial regeneration, a basic response to injury and essential for the restoration of the epithelial barrier integrity, begins with the spreading and migration of the viable respiratory epithelial cells edging the wound (27). We have previously demonstrated the unique affinity of P. aeruginosa for regenerating respiratory epithelial cells with a spreading shape similar to that observed for cells edging a wound (8,17).…”

Cytotoxicity of Pseudomonas aeruginosa internal lectin PA-I to respiratory epithelial cells in primary culture

“…These cells, which display lamellipodia and long filopodia, characteristics of migratory cells (34), are involved in the processes of epithelium differentiation and repair following injury. It has been demonstrated previously (14) that P. aenuginosa adherence to migratory epithelial cells in culture was significantly greater than that to nonmigratory cells. We observed that these migratory cells were more sensitive to PA-I lectin than the other respiratory cells.…”