title: Cathepsins B and L in synovial fluids from patients with rheumatoid arthritis and the effect of cathepsin B on the activation of pro-urokinase.
abstract: To clarify the pathophysiological role of cathepsins in rheumatoid arthritis (RA), we investigated whether cathepsin B or cathepsin L was increased in synovial fluid (SF) of RA joints, and whether the cathepsin isolated from SF of RA patients activated pro-urokinase or not. Thus, we estimated the content of cathepsins in SF of RA patients by measuring their activities by fluorospectrometry, using Z-Phe-Arg-MCA as the substrate. Cathepsin activity was approximately 4-fold higher in the SF of RA patients than in those of patients with osteoarthritis. Cathepsin B and cathepsin L were separated by cation-exchange column chromatography. As a result, a large peak corresponding to cathepsin B and a very small peak corresponding to cathepsin L were detected. Biochemical sequential fractionation of the cathepsin purified from the SF showed that the large peak was mainly composed of cathepsin B. This purified enzyme induced conversion of pro-urokinase to urokinase, and the Km for pro-urokinase was approximately 8.27 microM. These findings indicated that an imbalance between cathepsin B and its inhibitors occurred due to increased concentrations of active cathepsin B in RA articular lesions, and that cathepsin B might be related to the degradation of cartilage in RA by activating the fibrinolytic cascade.
authors.affiliation: Department of Orthopedic Surgery, University of Tokushima School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Ikata
authors.forename: T
authors.initials: T
authors.lastname: Mishiro
authors.forename: S
authors.initials: S
authors.lastname: Nakano
authors.forename: M
authors.initials: M
authors.lastname: Ikebe
authors.forename: S
authors.initials: S
authors.lastname: Yasuoka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000201:enzymology*; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D010450:Endopeptidases; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D005260:Female; D006801:Humans; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000201:enzymology; D011994:Recombinant Proteins / Q000378:metabolism; D013582:Synovial Fluid / Q000201:enzymology*; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
chemical_list: D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D004792:Enzyme Precursors; D011994:Recombinant Proteins; C068250:N-(3-propylcarbamoyloxirane-2-carbonyl)-isoleucyl-proline; D002403:Cathepsins; D010450:Endopeptidases; D014568:Urokinase-Type Plasminogen Activator; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534281:CTSL protein, human; D056668:Cathepsin L; D007930:Leucine; C024974:E 64; C067551:saruplase