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Sökning: AMNE:(MEDICIN OCH HÄLSOVETENSKAP Medicinska grundvetenskaper Läkemedelskemi) > Abrahamson Magnus

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1.
  • 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.
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2.
  • 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.
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3.
  • 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
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4.
  • Ekström, Ulf, et al. (författare)
  • Mutations in the low-density lipoprotein receptor gene in Swedish familial hypercholesterolaemia patients: clinical expression and treatment response
  • 1998
  • Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972. ; 28:9, s. 740-747
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Familial hypercholesterolaemia, an autosomal co-dominant disorder caused by defects in the low-density lipoprotein receptor gene, is strongly associated with premature development of cardiovascular disease. METHODS: In this study, we have applied a gene screening method in a population of familial hypercholesterolaemia patients in order to describe the genetic background of the disease in southern Sweden. These patients were studied with the aim of relating the presence of the different mutations to the clinical expression of the disease and to the response to pharmacological treatment. RESULTS: In 16 out of 21 patients, potentially disease-causing low-density lipoprotein receptor gene defects were found, including five not previously described alterations (C240-->F, C122-->stop, C356-->Y, 785insG, 165delG). No defects in apolipoprotein B were found. One group of patients (n = 4) carried the mutation C122-->stop and another group of patients (n = 4) a mutation causing the substitution W66-->G. Patients in the two genotype subgroups were very similar with respect to lipid levels before treatment. CONCLUSION: A tendency towards differential susceptibility to treatment with statins was observed for the patient groups, encouraging further comparative studies of heterozygous FH patients.
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5.
  • 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.
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6.
  • Lerner, Ulf H, et al. (författare)
  • Cysteine proteinases in osteoclast function and recruitment
  • 2004
  • Ingår i: Biological Mechanisms of Tooth Movement and Craniofacial Adaptation. - Boston, Massachusetts, USA : Harvard Society for the Advancement of Orthodontics. - 0963204750 ; , s. 227-227
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)
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7.
  • 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.
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8.
  • Gustafson, Lars, et al. (författare)
  • Apolipoprotein E genotyping in Alzheimer’s disease and frontotemporal dementia
  • 1997
  • Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 8:4, s. 240-243
  • Tidskriftsartikel (refereegranskat)abstract
    • Alzheimer's disease (AD) and frontotemporal dementia (FTD) are characterized by progressive neuronal loss and microvacuolization, although with different distributions of cortical involvement. In contrast to AD there is no amyloid, senile plaques or tangles in FTD. The involvement of chromosome 19 in AD has been associated with apoliprotein E (ApoE) and the epsi4 gene frequency has been related to increased risk and early onset of AD. Our analysis of frequency of the ApoE alleles in 38 patients with AD, 21 patients with FTD and 29 normal controls indicates an association of both AD and FTD with an increased frequency of the epsi4 allele and in AD also with homozygosity for epsi4. Our results might indicate that ApoE epsi4 is an important aggravating and pathoplastic factor in the presence of genetic and other determinants for the development of AD or FTD. A significantly higher epsi2 frequency in our FTD material compared to AD and normals might also indicate a connection with the distribution of cortical degeneration.
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9.
  • Frendéus, Katarina H, et al. (författare)
  • Macrophage Responses to Interferon-gamma are Dependent on Cystatin C Levels.
  • 2009
  • Ingår i: International Journal of Biochemistry and Cell Biology. - : Elsevier BV. - 1878-5875 .- 1357-2725. ; 41, s. 2262-2269
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the present investigation was to elucidate possible effects of cystatin C on inflammatory responses mediated by macrophages. Previously it has been shown that in vitro treatment of murine peritoneal macrophages with interferon-gamma (IFN-gamma) causes a down-regulation of cystatin C secretion. To investigate whether such changes in cystatin C expression in turn can affect inflammatory responses mediated by macrophages, we have compared effects of IFN-gamma on macrophages isolated from wild-type (cysC(+/+)) and cystatin C knockout (cysC(-/-)) mice. It was shown that IFN-gamma-primed cysC(-/-) macrophages exhibit significantly higher interleukin-10 (IL-10) but lower tumor necrosis factor-alpha (TNF-alpha) expression, and reduced nuclear factor (NF)-kappaB p65 activation, compared to similarily primed cysC(+/+) cells. Exogenously added cystatin C enhanced IFN-gamma-induced activation of NF-kappaB p65 and increased mRNA levels for inducible NO synthase (iNOS) in cysC(-/-) macrophages as well as levels of nitric oxide and TNF-alpha in the cell culture medium, in agreement with an enhanced pro-inflammatory response. Accordingly, IFN-gamma-induced IL-10 mRNA expression in cysC(-/-) macrophages was down-regulated by exogenously added cystatin C square. Taken together, our data provide evidence that changes in cystatin C levels alter macrophage responses to IFN-gamma. The latter downregulates the production of cystatin C, which leads to a suppressed inflammatory condition with enhanced IL-10 levels and downregulated TNF-alpha and NF-kappaB. It is concluded that cystatin C through this effect can act as an immunomodulatory molecule.
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10.
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