1.
Vincents, Bjarne, et al.
(författare)
Down-regulation of human extracellular cysteine protease inhibitors by the secreted staphylococcal cysteine proteases, staphopain A and B.
2007
Ingår i: Biological Chemistry. - 1437-4315. ; 388:4, s. 437-446
Tidskriftsartikel (refereegranskat) abstract
Of seven human cystatins investigated, none inhibited the cysteine proteases staphopain A and B secreted by the human pathogen Staphylococcus aureus. Rather, the extracellular cystatins C, D and E/M were hydrolyzed by both staphopains. Based on MALDI-TOF time-course experiments, staphopain A cleavage of cystatin C and D should be physiologically relevant and occur upon S. aureus infection. Staphopain A hydrolyzed the Glyl 1 bond of cystatin C and the Ala10 bond of cystatin D with similar K-m values of approximately 33 and 32 mu m, respectively. Such N-terminal truncation of cystatin C caused > 300-fold lower inhibition of papain, cathepsin B, L and K, whereas the cathepsin H activity was compromised by a factor of ca. 10. Similarly, truncation of cystatin D caused alleviated inhibition of all endogenous target enzymes investigated. The normal activity of the cystatins is thus down-regulated, indicating that the bacterial enzymes can cause disturbance of the host protease-inhibitor balance. To illustrate the in vivo consequences, a mixed cystatin C assay showed release of cathepsin B activity in the presence of staphopain A. Results presented for the specificity of staphopains when interacting with cystatins as natural protein substrates could aid in the development of therapeutic agents directed toward these proteolytic virulence factors.
2.
Brage, M, et al.
(författare)
Different cysteine proteinases involved in bone resorption and osteoclast formation.
2005
Ingår i: Calcified tissue international. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 76:6, s. 439-47
Tidskriftsartikel (refereegranskat) abstract
Cysteine proteinases, especially cathepsin K, play an important role in osteoclastic degradation of bone matrix proteins and the process can, consequently, be significantly inhibited by cysteine proteinase inhibitors. We have recently reported that cystatin C and other cysteine proteinase inhibitors also reduce osteoclast formation. However, it is not known which cysteine proteinase(s) are involved in osteoclast differentiation. In the present study, we compared the relative potencies of cystatins C and D as inhibitors of bone resorption in cultured mouse calvariae, osteoclastogenesis in mouse bone marrow cultures, and cathepsin K activity. Inhibition of cathepsin K activity was assessed by determining equilibrium constants for inhibitor complexes in fluorogenic substrate assays. The data demonstrate that whereas human cystatins C and D are equipotent as inhibitors of bone resorption, cystatin D is 10-fold less potent as an inhibitor of osteoclastogenesis and 200-fold less potent as an inhibitor of cathepsin K activity. A recombinant human cystatin C variant with Gly substitutions for residues Arg8, Leu9, Val10, and Trp106 did not inhibit bone resorption, had 1,000-fold decreased inhibitory effect on cathepsin K activity compared to wildtype cystatin C, but was equipotent with wildtype cystatin C as an inhibitor of osteoclastogenesis. It is concluded that (i) different cysteine proteinases are likely to be involved in bone resorption and osteoclast formation, (ii) cathepsin K may not be an exclusive target enzyme in any of the two systems, and (iii) the enzyme(s) involved in osteoclastogenesis might not be a typical papain-like cysteine proteinase.
3.
Olafsson, Isleifur, et al.
(författare)
Production, characterization and use of monoclonal antibodies against the major extracellular human cysteine proteinase inhibitors cystatin C and kininogen
1988
Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 48:6, s. 573-582
Tidskriftsartikel (refereegranskat) abstract
Murine monoclonal antibodies against the major cysteine proteinase inhibitors of human biological fluids, cystatin C and kininogen, were produced. The cystatin C antibody, HCC3, with a Ka of 2times107 l/mol, increased the inhibition of papain by cystatin C and was suitable for use in immunoblotting, immunohistochemistry and in the construction of a sensitive sandwich enzyme immunoassay for quantification of cystatin C. It recognized not only free cystatin C but also cystatin C in complexes with cysteine proteinases. The kininogen antibody, HK4, was directed against the third, cysteine proteinase inhibitory domain of the heavy chain of kininogen (Ka=1times107 l/mol), but did not influence the papain inhibitory activity of kininogen. It reacted with free kininogen as well as kininogen in complex with cysteine proteinases. Both antibodies could be used for the production of specific immunosorbents.
4.
Strålberg, Fredrik, et al.
(författare)
Inhibition of lipopolysaccharide-induced osteoclast formation and bone resorption in vitro and in vivo by cysteine proteinase inhibitors
2017
Ingår i: Journal of Leukocyte Biology. - : FEDERATION AMER SOC EXP BIOL. - 0741-5400 .- 1938-3673. ; 101:5, s. 1233-1243
Tidskriftsartikel (refereegranskat) abstract
Inflammation-induced bone destruction is a major treatment target in many inflammatory skeletal diseases. The aim of this study was to investigate if the cysteine proteinase inhibitors cystatin C, fungal cysteine proteinase inhibitor (E-64), and N-benzyloxycarbonyl-arginylleucyl-valyl-glycyl-diazomethane acetate (Z-RLVG-CHN2) can inhibit LPS-induced osteoclast formation. Mouse bone marrow macrophages (BMMs) were isolated and primed with receptor activator of NF-kappa B ligand (RANKL) for 24 h, followed by stimulation with LPS, with and without inhibitors. Adult mice were injected locally with LPS and then treated with E-64 and osteoclast formation assessed by the number of cathepsin K+ multinucleated cells. Cystatin C inhibited LPS-induced osteoclast formation time and concentration dependently (IC50 = 0.3 mu M). The effect was associated with decreased mRNA and protein expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K and of the osteoclastogenic transcription factors c-Fos and NFATc1. LPS-induced osteoclast formation on bone slices was also inhibited by cystatin C, resulting in decreased pit formation and release of bone matrix proteins. Similar data were obtained with E-64 and Z-RLVG-CHN2. Cystatin C was internalized in BMMs stimulated by LPS but not in unstimulated BMMs. Osteoclast formation induced by LPS was dependent on TNF-alpha, and the 3 inhibitors abolished LPS-induced TNF superfamily 2 (gene encoding TNF-alpha; Tnfsf2) mRNA expression without affecting Il1b, Il6, or oncostatin M (Osm) expression. Formation of osteoclasts in the skull bones after local LPS stimulation was inhibited by E-64. It is concluded that cysteine proteinase inhibitors effectively inhibit LPS-induced osteoclast formation in vivo and in vitro by inhibition of TNF-alpha expression. The targeting of cysteine proteinases might represent a novel treatment modality for prevention of inflammatory bone loss. RAHAMSON M, 1988, FEBS LETTERS, V236, P14 RAHAMSON M, 1990, BIOCHEMICAL JOURNAL, V268, P287
5.
Vincents, Bjarne, et al.
(författare)
The human protease inhibitor cystatin C is an activating cofactor for the streptococcal cysteine protease IdeS
2008
Ingår i: Chemistry and Biology. - : Elsevier BV. - 1074-5521 .- 1879-1301. ; 15:9, s. 960-968
Tidskriftsartikel (refereegranskat) abstract
Human cystatin C is considered the physiologically most important inhibitor of endogenous papain-like cysteine proteases. We present here an unexpected function of cystatin C. Instead of acting as an inhibitor, cystatin C acts as a facultative, endogenous cofactor for the papain-like IgG-cleaving enzyme IdeS of the human pathogen Streptococcus pyogenes. IdeS activity is not dependent on cystatin C, but is significantly enhanced in the presence of cystatin C. We report a protease inhibitor that accelerates the activity of its putative target protease and a unique example of how a host protease inhibitor is "hijacked" by a bacterial protease to increase its activity. This finding has important implications for the view on protease-inhibitor interactions, and is relevant to consider in the therapeutic use of protease inhibitors.
6.
7.
Abrahamson, Magnus
(författare)
Cystatins
1994
Ingår i: Methods in Enzymology. - : Elsevier. - 0076-6879. ; 244, s. 685-700
Tidskriftsartikel (refereegranskat)
8.
Abrahamson, Magnus, et al.
(författare)
Cystatins.
2003
Ingår i: Biochemical Society Symposia. - 0067-8694. ; 70, s. 179-199
Tidskriftsartikel (refereegranskat)
9.
10.