The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
Robert W. Colman - One of the best experts on this subject based on the ideXlab platform.
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[25] Human kallikrein and prekallikrein
Methods in Enzymology, 2004Co-Authors: Robert W. Colman, Andranik BagdasarianAbstract:Publisher Summary Kallikreins are proteases that specifically liberate kinins from plasma a2-globulin substrates known as Kininogens. In plasma, kallikrein exists in a precursor form known as prekallikrein. Kallikreins can be divided into two classes depending on the source from which the enzymes are isolated. This chapter centers on human plasma prekallikrein and kallikrein. The enzymic activity of kallikrein is measured by two methods. It also quantifies the rate of release of kinins as determined by bioassay or radioimmunoassay. Alternatively, the ability of kallikrein to hydrolyze synthetic basic amino acid esters can be assessed. It also elaborates on Kinin-Releasing Assay Bioassay, which utilizes the smooth muscle contractions elicited by bradykinin, released by the action of kallikrein on Kininogen. It also elaborates on Esterolytic Assay, in which methanol released from N-a-toluenesulfonyl-L-arginine methyl ester (TAME) is quantitated by the modification of the method of Siegelman et al. The chapter details the purification procedure and physical properties of Kallikreins and lists the natural and synthetic inhibitors.
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Kininogens Are Antithrombotic Proteins In Vivo
Arteriosclerosis thrombosis and vascular biology, 1999Co-Authors: Robert W. Colman, John V. White, Sherry Scovell, Antoni Stadnicki, Ryan B. SartorAbstract:Abstract—Kininogens have recently been shown to possess antiadhesive, anticoagulant, and profibrinolytic properties and can inhibit platelet activation at low thrombin concentrations. To test whether Kininogens have antithrombotic properties in vivo, we devised a model of limited arterial injury confined to removal of the endothelium. Brown-Norway Katholiek strain rats with an absence of low- and high-molecular-weight Kininogen due to a single point mutation, A163T, were compared in the thrombosis model to the wild-type animals, which were otherwise genetically identical. Despite an equivalent vascular injury, the mean time (±SEM) for a 90% decrease in flow measured by laser Doppler was 38.4±17 minutes in the Kininogen-deficient rats compared with 194±29 minutes in the wild-type animals (P
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Inhibitory and antiadhesive properties of human Kininogens.
Immunopharmacology, 1996Co-Authors: Robert W. ColmanAbstract:Each of 11 exons of the human Kininogen gene has the potential to code for different functional activities of the molecule in both bradykinin formation and interactions with platelets, neutrophils and endothelial cells. Our recent studies have localized amino acid sequences in exon 4 product and exon 5 product in domain 2, which bind and inhibit platelet calpain, respectively. Furthermore, we have shown that the exon 7 product expressed in domain 3 contains a decapeptide which interacts with thrombospondin on activated platelets, and a distinct septapeptide which inhibits thrombin-induced activation of platelets. Exon 8 and 9 products cooperate to inhibit cathepsins B and H. Domain 3 also contains a cell binding site for neutrophils, as does domain 5. Fine mapping of both cell binding domains has been performed by several groups of investigators for neutrophils, endothelial cells and platelets. The cell binding domain in D5 overlaps with the anionic surface binding subdomain of D5. The monomeric structure of Kininogen assures that it will function as an antiadhesive protein, unlike dimeric fibrinogen. High molecular weight Kininogen competes with fibrinogen binding to neutrophils and platelets. We have also fine mapped the domains for binding of Kininogen (domain 6) to prekallikrein 'apple' domains 1 and 4. Kininogens can serve as proinflammatory proteins by releasing bradykinin, but cleaved Kininogens exhibit antiadhesive and anti-inflammatory properties.
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Structure and functions of human Kininogens
Trends in pharmacological sciences, 1991Co-Authors: Raul A. Dela Cadena, Robert W. ColmanAbstract:Abstract Evidence has accumulated over the past three decades implicating plasma Kininogens in numerous inflammatory processes. Delineation of the detailed biochemistry and, more recently, the molecular biology of the human Kininogens has resulted in a deeper understanding of the structure-function correlations of the human Kininogens. Studies of alterations of human Kininogens in disease states have yielded information about the mechanisms of their involvement in inflammatory states. Here, Raul DeLa Cadena and Robert Colman summarize kirinogen function in relation to structure and diagnostic and therapeutic potential.
Alvin H. Schmaier - One of the best experts on this subject based on the ideXlab platform.
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Deletion of Murine Kininogen Gene 1 (mKNG1) Causes Loss of Plasma Kininogen and Delays Thrombosis.
Blood, 2007Co-Authors: Sergei Merkulov, Alvin H. Schmaier, Anton A. Komar, Ellen Barnes, Yihua Zhou, Guangbin Lou, Keith R. MccraeAbstract:Abstract High molecular weight Kininogen (HK) plays an important role in the assembly of the plasma kallikrein-kinin system. While the human genome contains a single copy of the Kininogen gene, three copies exist in the rat (one encoding K-Kininogen and two encoding T-Kininogen). Here, we confirm that the mouse genome contains two homologous Kininogen genes, mKng1 and mKng2. These genes are located on chromosome 16 in a head to head orientation with ∼ 30 kB intervening sequence, and are expressed in a tissue-specific manner. To determine the roles of these genes in murine development and physiology, we disrupted mKng1, which is expressed primarily in the liver. mKng1−/ − mice were viable, and immunoblotting using anti-bradykinin antibodies indicated a marked reduction in plasma HK and low molecular weight Kininogen (LK), as well as ΔmHK-D5, a novel Kininogen isoform that lacks Kininogen domain 5. Clotting studies were also consistent with marked HK deficiency. Moreover, despite normal tail vein bleeding times, mKng1−/− mice displayed a significantly prolonged time to carotid artery occlusion following Rose Bengal administration and laser induced arterial injury. These results suggest that a single gene, mKng1, is responsible for production of plasma Kininogen, and that plasma high molecular weight Kininogen may contribute to induced arterial thrombosis in mice.
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Deletion of murine Kininogen gene 1 (mKng1) causes loss of plasma Kininogen and delays thrombosis
Blood, 2007Co-Authors: Sergei Merkulov, Alvin H. Schmaier, Wan Ming Zhang, Anton A. Komar, Ellen Barnes, Yihua Zhou, Takayuki Iwaki, Francis J. Castellino, Guangbin LuoAbstract:High-molecular-weight Kininogen (HK) plays an important role in the assembly of the plasma kallikrein-kinin system. While the human genome contains a single copy of the Kininogen gene, 3 copies exist in the rat (1 encoding K-Kininogen and 2 encoding T-Kininogen). Here, we confirm that the mouse genome contains 2 homologous Kininogen genes, mKng1 and mKng2, and demonstrate that these genes are expressed in a tissue-specific manner. To determine the roles of these genes in murine development and physiology, we disrupted mKng1, which is expressed primarily in the liver. mKng1−/− mice were viable, but lacked plasma HK and low-molecular-weight Kininogen (LK), as well as ΔmHK-D5, a novel Kininogen isoform that lacks Kininogen domain 5. Moreover, despite normal tail vein bleeding times, mKng1−/− mice displayed a significantly prolonged time to carotid artery occlusion following Rose Bengal administration and laser-induced arterial injury. These results suggest that a single gene, mKng1, is responsible for production of plasma Kininogen, and that plasma HK contributes to induced arterial thrombosis in mice.
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The Pharmacokinetics of the Kininogens
Thrombosis research, 1998Co-Authors: Alvin H. Schmaier, Richard L. Wahl, Susan J. Fisher, Dean E. BrennerAbstract:Abstract Recent evidence has shown that plasma high molecular weight Kininogen and both Kininogens have the ability to modulate prekallikrein activation and thrombin-induced platelet activation, respectively. However, nothing is known about the plasma clearance and tissue distribution of these proteins. We examined the in vivo pharmacokinetics of high (HK) and low (LK) molecular weight Kininogens in rats. 125 I-HK and -LK molecular weight Kininogens’ clearance in rats best-fitted a biexponential model. For HK, the t 1/2 α and t 1/2 β were 0.6 and 9.5 h and for LK, 0.78 and 7.4 h, respectively. 125 I-kinin-free HK (cleaved HK) was cleared with a t 1/2 α and t 1/2 β of 0.45 and 9.9 h, respectively. 125 I-Domain 3 of Kininogens was cleared with a t 1/2 β and t 1/2 c of 0.99 and 13.3 h, respectively. HK was mostly concentrated in lung; LK, domain 3, and cleaved HK were mostly concentrated in kidney. The Kininogens were also concentrated in liver, spleen, and skin. These studies indicate that protein size rather than form is the major determinant of its clearance. Furthermore, the distribution of the Kininogens is where bradykinin metabolism and activity are well described.
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Gene Expression, Regulation and Cell Surface Presentation of the Kininogens
The Kinin System, 1997Co-Authors: Alvin H. SchmaierAbstract:Publisher Summary This chapter discusses the key areas for future investigation in a vibrant and evolving field of vascular biology. Although first recognized 21 years ago as a defect associated with a very prolonged activated partial thromboplastin time (APTT), the genetic deficiency of high-molecular-weight Kininogen (HMWK) is not associated with bleeding. These features have been both a benefit and a discomfort to investigators in this field. Recognition of HMWK deficiency is greatly facilitated by prolongation of the APTT, although the homozygous HMWK-deficient patient is rare. Alternatively, the prolonged APTT associated with HMWK deficiency has contributed to the masking of the physiological importance of HMWK as an antithrombin and its role in ordering the assembly and activation of a plasma kallikrein (KLK)-dependent fibrinolytic pathway on biologic membranes. These activities are paradoxical to any prolongation of a screening test for bleeding. The weight of current evidence indicates that the Kininogens, especially HMWK, are antithrombins and profibrinolytic proteins. The chapter discusses the gene expression and regulation of Kininogens, protein chemistry in Kininogens, the function of Kininogens in relation to their structures, and characterization of Kininogen expression on biological membranes and emphasizes the physiological activities of the Kininogens based upon their functions. HMWK and low-molecular-weight Kininogen (LMWK) assemble on cell membranes, allowing bradykinin (BK) to be liberated in a protected environment, wherein this potent, bioactive peptide can activate its receptors to influence vascular biology.
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Insights on monoclonal antibodies to Kininogens' heavy chain which influence Kininogens' binding to platelets.
Thrombosis and haemostasis, 1992Co-Authors: Yongping Jiang, Weerasak Nawarawong, Frank J. Meloni, Alvin H. SchmaierAbstract:Purified domains of low molecular weight Kininogen (LK) can be used directly to determine the epitopes of monoclonal antibodies (mAbs) that have been shown to influence Kininogen function. LK, purified from plasma by carboxymethyl-papain-Sepharose 4B affinity chromatography and kaolin adsorption, was digested by trypsin and chymotrypsin. The domains of LK were then separated by gel filtration followed by carboxymethyl-papain-Sepharose 4B affinity chromatography. Using the purified domains of LK's heavy chain, the regions on Kininogens' heavy chain which various monoclonal antibodies are directed to were determined by enzyme-linked immunosorbent assay and immunoblotting. MAb 2B5 which neutralized Kininogens' ability to inhibit calpain cross-reacted with domains 2 and 3. MAb HKH8 which reacted with Kininogens' domain 1 and 2 was found to inhibit 125I-HK binding to platelets. At two-fold molar excess, mAb HKH8 was a better inhibitor of 125I-HK binding to platelets than higher concentrations, where the antibody was shown to cause increased binding to platelets. Alternatively, HKH8 F(ab')2 completely inhibited 125I-HK binding to platelets even at high concentrations of antibody. These studies indicate that purified domains of Kininogens' heavy chain can be used to rapidly localize epitopes for antibodies. Further, mAb HKH8 should be a valuable probe to understand the mechanisms of Kininogens' binding to platelets.
Werner Mulleresterl - One of the best experts on this subject based on the ideXlab platform.
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high molecular weight Kininogen utilizes heparan sulfate proteoglycans for accumulation on endothelial cells
Journal of Biological Chemistry, 2000Co-Authors: Thomas Renne, Jürgen Dedio, Guido David, Werner MulleresterlAbstract:Kininogens, the high molecular weight precursor of vasoactive kinins, bind to a wide variety of cells in a specific, reversible, and saturable manner. The cell docking sites have been mapped to domains D3 and D5(H) of Kininogens; however, the corresponding cellular acceptor sites are not fully established. To characterize the major cell binding sites for Kininogens exposed by the endothelial cell line EA.hy926, we digested intact cells with trypsin and other proteases and found a time- and concentration-dependent loss of (125)I-labeled high molecular weight Kininogen (H-Kininogen) binding capacity (up to 82%), indicating that proteins are crucially involved in Kininogen cell attachment. Cell surface digestion with heparinases similarly reduced Kininogen binding capacity (up to 78%), and the combined action of heparinases and trypsin almost eliminated Kininogen binding (up to 85%), suggesting that proteoglycans of the heparan sulfate type are intimately involved. Consistently, inhibitors such as p-nitrophenyl-beta-d-xylopyranoside and chlorate interfering with heparan sulfate proteoglycan biosynthesis reduced the total number of Kininogen binding sites in a time- and concentration-dependent manner (up to 67%). In vitro binding studies demonstrated that biotinylated H-Kininogen binds to heparan sulfate glycosaminoglycans via domains D3 and D5(H) and that the presence of Zn(2+) promotes this association. Cloning and over-expression of the major endothelial heparan sulfate-type proteoglycans syndecan-1, syndecan-2, syndecan-4, and glypican in HEK293t cells significantly increased total heparan sulfate at the cell surface and thus the number of Kininogen binding sites (up to 3. 3-fold). This gain in Kininogen binding capacity was completely abolished by treating transfected cells with heparinases. We conclude that heparan sulfate proteoglycans on the surface of endothelial cells provide a platform for the local accumulation of Kininogens on the vascular lining. This accumulation may allow the circumscribed release of short-lived kinins from their precursor molecules in close proximity to their sites of action.
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mapping of the discontinuous h Kininogen binding site of plasma prekallikrein evidence for a critical role of apple domain 2
Journal of Biological Chemistry, 1999Co-Authors: Thomas Renne, Jürgen Dedio, Joost C M Meijers, Dominic Chung, Werner MulleresterlAbstract:Plasma prekallikrein, a zymogen of the contact phase system, circulates in plasma as heterodimeric complex with H-Kininogen. The binding is mediated by the prekallikrein heavy chain consisting of four apple domains, A1 to A4, to which H-Kininogen binds with high specificity and affinity (K(D) = 1.2 x 10(-8) M). Previous work had demonstrated that a discontinuous Kininogen-binding site is formed by a proximal part located in A1, a distal part exposed by A4, and other yet unidentified portion(s) of the kallikrein heavy chain. To detect relevant binding segment(s) we recombinantly expressed single apple domains and found a rank order of binding affinity for Kininogen of A2 > A4 approximately A1 > A3. Removal of single apple domains in prekallikrein deletion mutants reduced Kininogen binding by 21 (A1), 64 (A2), and 24% (A4), respectively, whereas deletion of A3 was without effect. Transposition of homologous A2 domain from prekallikrein to factor XI conferred high-affinity Kininogen binding from the former to the latter. The principal role of A2 for H-Kininogen docking to the prekallikrein heavy chain was further substantiated by the finding that cleavage of a single peptide bond in A2 drastically diminished the H-Kininogen binding affinity. Furthermore, the epitope of monoclonal antibody PKH6 which blocks kallikrein-Kininogen complex formation with an IC(50) of 8 nM mapped to the center portion of domain A2. Our data indicate that domain A2 and two flanking sequence segments of A1 and A4 form a discontinuous binding platform for H-Kininogen on the prekallikrein heavy chain. Domain-specific antibodies directed to these critical sites efficiently interfered with contact phase-induced bradykinin release from H-Kininogen.
Andranik Bagdasarian - One of the best experts on this subject based on the ideXlab platform.
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[25] Human kallikrein and prekallikrein
Methods in Enzymology, 2004Co-Authors: Robert W. Colman, Andranik BagdasarianAbstract:Publisher Summary Kallikreins are proteases that specifically liberate kinins from plasma a2-globulin substrates known as Kininogens. In plasma, kallikrein exists in a precursor form known as prekallikrein. Kallikreins can be divided into two classes depending on the source from which the enzymes are isolated. This chapter centers on human plasma prekallikrein and kallikrein. The enzymic activity of kallikrein is measured by two methods. It also quantifies the rate of release of kinins as determined by bioassay or radioimmunoassay. Alternatively, the ability of kallikrein to hydrolyze synthetic basic amino acid esters can be assessed. It also elaborates on Kinin-Releasing Assay Bioassay, which utilizes the smooth muscle contractions elicited by bradykinin, released by the action of kallikrein on Kininogen. It also elaborates on Esterolytic Assay, in which methanol released from N-a-toluenesulfonyl-L-arginine methyl ester (TAME) is quantitated by the modification of the method of Siegelman et al. The chapter details the purification procedure and physical properties of Kallikreins and lists the natural and synthetic inhibitors.
Andrzej Kozik - One of the best experts on this subject based on the ideXlab platform.
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kinin release from human Kininogen by 10 aspartic proteases produced by pathogenic yeast candida albicans
BMC Microbiology, 2015Co-Authors: Andrzej Kozik, Mariusz Gogol, Oliwia Bochenska, Justyna Karkowskakuleta, Natalia Wolak, Wojciech Kamysz, Wataru Aoki, Mitsuyoshi Ueda, Alexander Faussner, Maria RapalakozikAbstract:Candida albicans yeast produces 10 distinct secreted aspartic proteases (Saps), which are some of the most important virulence factors of this pathogenic fungus. One of the suggested roles of Saps is their deregulating effect on various proteolytic cascades that constitute the major homeostatic systems in human hosts, including blood coagulation, fibrinolysis, and kallikrein-kinin systems. This study compared the characteristics of the action of all 10 Saps on human Kininogens, which results in generating proinflammatory bradykinin-related peptides (kinins). Recombinant forms of Saps, heterologously overexpressed in Pichia pastoris were applied. Except for Sap7 and Sap10, all Saps effectively cleaved the Kininogens, with the highest hydrolytic activity toward the low-molecular-mass form (LK). Sap1–6 and 8 produced a biologically active kinin—Met-Lys-bradykinin—and Sap3 was exceptional in terms of the kinin-releasing yield (>60% LK at pH 5.0 after 24 hours). Des-Arg1-bradykinin was released from LK by Sap9 at a comparably high yield, but this peptide was assumed to be biologically inactive because it was unable to interact with cellular B2-type kinin receptors. However, the collaborative actions of Sap9 and Sap1, −2, −4–6, and −8 on LK rerouted Kininogen cleavage toward the high-yield release of the biologically active Met-Lys-bradykinin. Our present results, together with the available data on the expression of individual SAP genes in candidal infection models, suggest a biological potential of Saps to produce kinins at the infection foci. The kinin release during candidiasis can involve predominant and complementary contributions of two different Sap3- and Sap9-dependent mechanisms.
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Kininogen binding to the surfaces of macrophages.
International immunopharmacology, 2007Co-Authors: Anna Barbasz, Ibeth Guevara-lora, Maria Rapala-kozik, Andrzej KozikAbstract:Kinin generation may be initiated on the cell surfaces via a primary Kininogen docking which has been characterized for endothelial cells, platelets, neutrophils, astrocytes and smooth muscle cells. In this work we describe the adsorption of biotin-labeled human Kininogens by murine RAW 264.7 macrophages and human U-937 monocytes/macrophages. Both cell types strongly bound high molecular mass Kininogen (HK) in a zinc-ion dependent manner with the dissociation constants of 9.1 nM and 3.3 nM, respectively, and the binding capacities of 46 fmol and 71 fmol per million of respective cells. The HK binding was quenched by 50% by antibodies against Mac-1, gC1qR and uPAR proteins indicating that these macrophage surface receptors are involved in the HK adsorption. A significant increase of HK binding was observed after cell activation with phorbol myristate acetate. Our results suggest that macrophages, similarly to neutrophils, may supply Kininogens to the inflammatory foci to support the local kinin production at these sites.
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Properties of chemically oxidized Kininogens.
Acta biochimica Polonica, 2003Co-Authors: Magdalena Nieziołek, Marcin Kot, Krzysztof Pyka, Paweł Mak, Andrzej KozikAbstract:Kininogens are multifunctional proteins involved in a variety of regulatory processes including the kinin-formation cascade, blood coagulation, fibrynolysis, inhibition of cysteine proteinases etc. A working hypothesis of this work was that the properties of Kininogens may be altered by oxidation of their methionine residues by reactive oxygen species that are released at the inflammatory foci during phagocytosis of pathogen particles by recruited neutrophil cells. Two methionine-specific oxidizing reagents, N-chlorosuccinimide (NCS) and chloramine-T (CT), were used to oxidize the high molecular mass (HK) and low molecular mass (LK) forms of human Kininogen. A nearly complete conversion of methionine residues to methionine sulfoxide residues in the modified proteins was determined by amino acid analysis. Production of kinins from oxidized Kininogens by plasma and tissue kallikreins was significantly lower (by at least 70%) than that from native Kininogens. This quenching effect on kinin release could primarily be assigned to the modification of the critical Met-361 residue adjacent to the internal kinin sequence in Kininogen. However, virtually no kinin could be formed by human plasma kallikrein from NCS-modified HK. This observation suggests involvement of other structural effects detrimental for kinin production. Indeed, NCS-oxidized HK was unable to bind (pre)kallikrein, probably due to the modification of methionine and/or tryptophan residues at the region on the Kininogen molecule responsible for the (pro)enzyme binding. Tests on papain inhibition by native and oxidized Kininogens indicated that the inhibitory activity of Kininogens against cysteine proteinases is essentially insensitive to oxidation.
