Inhibition of interleukin 1-stimulated cartilage proteoglycan degradation by a lipophilic inactivator of cysteine endopeptidases.
Inactivators of cysteine endopeptidases were tested as inhibitors of the cytokine-stimulated release of proteoglycan from cartilage. The test system consisted of bovine nasal septum cartilage maintained in organ culture, and the stimulus was provided by recombinant human interleukin 1 alpha. L-3-Carboxy-2,3-trans-epoxypropionyl-leucylamido-(4-guanidin o)butane (E64) and L-3-carboxy-2,3-trans-epoxypropionyl-leucylamido-(3-methyl)b utane (Ep475) showed no inhibition at concentrations up to 100 microM. In contrast, trans-epoxysuccinyl-leucylamido-(3-methyl)butane ethyl ester (Ep453), a 'prodrug' of Ep475, was an effective inhibitor. The LL-, LD- and DL-isomers gave significant inhibition at 10 microM, and the DD-isomer was inhibitory at 100 microM. None of the isomers had any detectable effect on protein synthesis or glycolysis, and their inhibitory effects were reversible. Iodoacetate inhibited proteoglycan release by a general toxic effect. Our results suggest that cysteine endopeptidase(s) play a part in cytokine-stimulated cartilage breakdown, but that effective inhibitors must pass through membranes.
Buttle
D J
DJ
Department of Biochemistry, Strangeways Research Laboratory, Worts Causeway, Cambridge, U.K.
Saklatvala
J
J
Tamai
M
M
Barrett
A J
AJ
D000818:Animals; D002356:Cartilage / Q000378:metabolism*; D002417:Cattle; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology*; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007930:Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011509:Proteoglycans / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
D015853:Cysteine Proteinase Inhibitors; D007375:Interleukin-1; D007461:Iodoacetates; D011509:Proteoglycans; D011994:Recombinant Proteins; C032425:N-(N-(3-carboxyoxirane-2-carbonyl)leucyl)isoamylamine; D007930:Leucine; C108192:aloxistatin; C024974:E 64; D019807:Iodoacetic Acid