Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.
Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL)CH[CH2CH(CH3)2]CO-Phe-Ala-NH2, which we previously showed to be a potent inhibitor of corneal collagenase and alkali-induced corneal ulceration, was tested as a potential inhibitor of P. aeruginosa elastase. Inhibition constants (Kis) for the resolved diastereomers were determined with the chromogenic substrate furylacryloyl-glycyl-L-leucyl-L-alanine. One isomer had a Ki of 0.3 microM, while the other had a Ki of 0.4 microM. The more potent diastereomer was evaluated in vivo in experimentally induced Pseudomonas keratitis in rabbits. Following inoculation of one cornea of each rabbit, topical treatment with a 1 mM solution of the inhibitor significantly delayed the onset of corneal melting and perforation, as compared with the results for the control and gentamicin-treated groups. This protective effect suggests that the inhibitor may have a therapeutic application by delaying the progression of corneal destruction in Pseudomonas keratitis.
Burns
F R
FR
Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Kentucky 40292.
Paterson
C A
CA
Gray
R D
RD
Wells
J T
JT
D000595:Amino Acid Sequence; D000818:Animals; D002863:Chromogenic Compounds / Q000378:metabolism; D003315:Cornea / Q000382:microbiology; D004151:Dipeptides / Q000494:pharmacology*; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D005839:Gentamicins / Q000627:therapeutic use; D007634:Keratitis / Q000188:drug therapy* / Q000382:microbiology; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000494:pharmacology*
D002863:Chromogenic Compounds; D004151:Dipeptides; D005839:Gentamicins; D013438:Sulfhydryl Compounds; C067592:mercaptomethyl-4-methylpentanoyl-phenylalanylalaninamide; D010196:Pancreatic Elastase; D008666:Metalloendopeptidases