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Proteinase K decreases Pseudomonas aeruginosa adhesion to wounded cornea
L D Hazlett1, S Masinick, R S Berk
1Department of Anatomy/Cell Biology, Wayne State University, Detroit, MI 48201.
Abstract:
The present study was designed to obtain further information regarding the molecular nature of the corneal receptor(s) facilitating Pseudomonas aeruginosa adhesion to cornea. Scarified adult mouse corneas in organ culture were treated for 10 or 60 min with a panel of lipase-free proteases [each at 20 micrograms ml-1 or 0.22 Units (U) ml-1, activity] including trypsin, chymotrypsin, V8 protease, elastase, subtilisin A, pronase protease and proteinase K. All of these, except proteinase K treatment (20 micrograms ml-1 for 60 min), either significantly elevated or had no effect (proteinase K 20 micrograms ml-1 for 10 min) on subsequent bacterial adhesion at 60 min following topical application of the inoculum to the scarified corneal surface. Enzyme treatment times of 10, 30 or 60 min at a higher concentration (50 micrograms ml-1) of proteinase K, significantly decreased binding at 60 min after bacterial application for each enzyme treatment time. The combined effects of proteases and lipase on bacterial binding also was examined. Eyes treated with proteinase K (20 micrograms ml-1 for 1 hr) or protease-free lipase (50,000 U ml-1 for 1 hr) alone or in combination, all reduced bacterial binding, but the effect was not additive. Trypsin or lipase alone significantly enhanced or decreased binding, respectively. In contrast, trypsin (20 micrograms ml-1 for 1 hr) followed by lipase treatment (50,000 U ml-1 for 1 hr) resulted in binding which was not significantly different than phosphate-buffered saline (PBS) control binding, indicating that the trypsin exposed receptor was lipase sensitive.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
This study investigated how enzymes affect Pseudomonas aeruginosa binding to the cornea. Protease treatments generally increased bacterial adhesion, but proteinase K and lipase reduced it, revealing a lipase-sensitive corneal receptor.
Area of Science:
- Microbiology
- Ophthalmology
- Biochemistry
Background:
- Pseudomonas aeruginosa is a major cause of bacterial keratitis.
- Understanding corneal receptors involved in bacterial adhesion is crucial for developing preventative strategies.
Purpose of the Study:
- To elucidate the molecular nature of corneal receptors mediating Pseudomonas aeruginosa adhesion.
- To investigate the role of proteases and lipase in modulating bacterial binding to the cornea.
Main Methods:
- Scarified adult mouse corneas in organ culture were treated with various lipase-free proteases (trypsin, chymotrypsin, V8 protease, elastase, subtilisin A, pronase, proteinase K).
- Bacterial adhesion of Pseudomonas aeruginosa was quantified following enzyme treatments.
- Combined effects of proteases and lipase on bacterial binding were examined.
Main Results:
- Most proteases either increased or had no effect on bacterial adhesion, except proteinase K which decreased binding at higher concentrations and longer incubation times.
- Proteinase K and lipase alone, or in combination, reduced bacterial binding, but the effect was not additive.
- Trypsin treatment followed by lipase resulted in bacterial binding levels similar to controls, indicating a lipase-sensitive receptor exposed by trypsin.
Conclusions:
- Corneal receptors involved in Pseudomonas aeruginosa adhesion are sensitive to enzymatic modification.
- Specific proteases like proteinase K and lipase can significantly reduce bacterial adhesion.
- The findings suggest a complex interaction between bacterial adhesins and corneal surface molecules, with potential implications for anti-adhesion therapies.