Pseudomonas aeruginosa binds to extracellular matrix deposited by human corneal epithelial cells.
OBJECTIVE
To measure the effect of extracellular matrix substrate, pH, and O(2) on Pseudomonas aeruginosa binding.


METHODS
Extracellular matrix substrates were prepared from human corneal epithelial cells cultured in 2% or 20% O(2). P. aeruginosa strains ATCC 19660 or PAO1 (suspended in pH 7.0 or 7.5 buffer) were cultured on extracellular matrix substrates in 2% or 20% O(2). The mean number of adherent bacteria per counted per field +/- SEM (n = 15) was determined for combinations of bacteria, extracellular matrix substrate, pH, and O(2). Binding in the presence of antibodies directed against laminin-5 was also measured.


RESULTS
Extracellular matrix substrates produced by cells cultured in 20% O(2), combined with an environment of pH 7.0, provided the least favorable conditions for binding of strain 19660. In contrast, extracellular matrix substrates produced by cells cultured in 2% O(2), combined with an environment of pH 7.0, provided the most favorable conditions for binding of strain 19660. Binding of PAO1, however, as a function of extracellular matrix substrate and pH, did not similarly compare with binding of strain 19660. Antibodies against laminin-5 chains served to increase the number of strain 19660 bacteria bound to extracellular matrix substrates compared with the control.


CONCLUSIONS
The extracellular matrix secreted by hypoxic corneal epithelial cells is a substrate for binding of P. aeruginosa. Results in previous studies have shown that hypoxic extracellular matrix contains less laminin-5 protein than normoxic matrix. The antibody studies in this report suggest that the decrease in laminin-5 content in hypoxic matrix, relative to matrix secreted by normoxic corneal epithelium, may be responsible for increased bacterial adhesion.
Esco
Miechia A
MA
Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Hazlett
Linda D
LD
Kurpakus-Wheater
Michelle
M
D000293:Adolescent; D001422:Bacterial Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000382:microbiology* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism* / Q000382:microbiology* / Q000648:ultrastructure; D006801:Humans; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism; D008297:Male; D008855:Microscopy, Electron, Scanning; D011550:Pseudomonas aeruginosa / Q000502:physiology* / Q000648:ultrastructure; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D000097794:Kalinin