scholarly journals Fibrin – Fibrinogen scaffold structural modification by phytochemicals and phytoproteases contained in an aqueous extract of Ageratum conyzoides Linn.

2021 ◽  
Vol 15 (1) ◽  
pp. 1-11
Author(s):  
Amivi Edefia Akpalo ◽  
Kwami Lumo Awaga ◽  
Amivi Kafui Tete-Benissan
Keyword(s):  
Serine Proteases ◽  
Structural Modification ◽  
Fibrin Clot ◽  
Thrombin Inhibitors ◽  
Ageratum Conyzoides ◽  
Fibrin Gels ◽  
Coomassie Blue ◽  
Fibrin Networks ◽  
History Of ◽  
Serine Proteases Inhibitors

Based on mechanisms of fibrin clot polymerization and dissolution, it is possible to modulate fibrin formation and removal. Ageratum conyzoides Linn. (Asteraceae) is an annual herb with a long history of traditional medicine. There is high variability in the secondary metabolites of this plant which include flavonoids, and these molecules belong to a class of serine proteases inhibitors. Several plant enzymes belonging to the classes of serine proteases were observed to be active on the cascade of coagulation pathways. The aim of this study was to observe if even Ageratum conyzoides Linn. aqueous leaves extract contained proteases which could structurally modify the fibrin clot formation. To prepare plant extracts, dry leaves of the plant were extracted with distilled water. Fibrin gels were prepared by mixtures containing fibrinogen and thrombin with or without extract. Fibrin networks were disrupted by a denaturation buffer. Samples were deposited in 8% polyacrylamide gel and Coomassie blue was used to reveal migration. Our extract contained phytochemicals class flavonoids which are thrombin inhibitors. But our results support the evidence that the same extract contained plant serine proteases, specifically a fibrinogenase which hydrolyzed fibrinogen but not like thrombin.Keywords: Fibrin/Fibrinogen, structural modification, Ageratum conyzoides Linn., phytoproteases.

scholarly journals Serine Proteases Degrade Airway Mucins in Cystic Fibrosis

2011 ◽  
Vol 79 (8) ◽  
pp. 3438-3444 ◽  
Author(s):  
Markus O. Henke ◽  
Gerrit John ◽  
Christina Rheineck ◽  
Shashi Chillappagari ◽  
Lutz Naehrlich ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Serine Proteases ◽  
Defense Mechanism ◽  
Normal Subjects ◽  
Human Neutrophil Elastase ◽  
Content Type ◽  
Significant Difference ◽  
History Of ◽  
Serine Proteases Inhibitors ◽  
Normal Controls

ABSTRACTAirway mucins are the major molecular constituents of mucus. Mucus forms the first barrier to invading organisms in the airways and is an important defense mechanism of the lung. We confirm that mucin concentrations are significantly decreased in airway secretions of subjects with cystic fibrosis (CF) who have chronicPseudomonas aeruginosainfection. In sputum from CF subjects without a history ofP. aeruginosa, we found no significant difference in the mucin concentration compared to mucus from normal controls. We demonstrate that mucins can be degraded by synthetic human neutrophil elastase (HNE) andP. aeruginosaelastase B (pseudolysin) and that degradation was inhibited by serine proteases inhibitors (diisopropyl fluorophosphates [DFP], phenylmethylsulfonyl fluoride [PMSF], and 1-chloro-3-tosylamido-7-amino-2-heptanone HCl [TLCK]). The mucin concentration in airway secretions from CF subjects is similar to that for normal subjects until there is infection byP. aeruginosa, and after that, the mucin concentration decreases dramatically. This is most likely due to degradation by serine proteases. The loss of this mucin barrier may contribute to chronic airway infection in the CF airway.

scholarly journals Heparin-induced thrombocytopenia: in vitro studies on the interaction of dabigatran, rivaroxaban, and low-sulfated heparin, with platelet factor 4 and anti-PF4/heparin antibodies

Blood ◽  
2012 ◽  
Vol 119 (5) ◽  
pp. 1248-1255 ◽  
Author(s):  
Krystin Krauel ◽  
Christine Hackbarth ◽  
Birgitt Fürll ◽  
Andreas Greinacher
Keyword(s):  
Factor Xa ◽  
Platelet Factor 4 ◽  
Thrombin Inhibitors ◽  
Direct Thrombin Inhibitors ◽  
Platelet Factor ◽  
Heparin Induced Thrombocytopenia ◽  
Alternative Anticoagulation ◽  
Heparin Complexes ◽  
History Of

Abstract Heparin is a widely used anticoagulant. Because of its negative charge, it forms complexes with positively charged platelet factor 4 (PF4). This can induce anti-PF4/heparin IgG Abs. Resulting immune complexes activate platelets, leading to the prothrombotic adverse drug reaction heparin-induced thrombocytopenia (HIT). HIT requires treatment with alternative anticoagulants. Approved for HIT are 2 direct thrombin inhibitors (DTI; lepirudin, argatroban) and danaparoid. They are niche products with limitations. We assessed the effects of the DTI dabigatran, the direct factor Xa-inhibitor rivaroxaban, and of 2-O, 3-O desulfated heparin (ODSH; a partially desulfated heparin with minimal anticoagulant effects) on PF4/heparin complexes and the interaction of anti-PF4/heparin Abs with platelets. Neither dabigatran nor rivaroxaban had any effect on the interaction of PF4 or anti-PF4/heparin Abs with platelets. In contrast, ODSH inhibited PF4 binding to gel-filtered platelets, displaced PF4 from a PF4-transfected cell line, displaced PF4/heparin complexes from platelet surfaces, and inhibited anti-PF4/heparin Ab binding to PF4/heparin complexes and subsequent platelet activation. Dabigatran and rivaroxaban seem to be options for alternative anticoagulation in patients with a history of HIT. ODSH prevents formation of immunogenic PF4/heparin complexes, and, when given together with heparin, may have the potential to reduce the risk for HIT during treatment with heparin.

scholarly journals The Evolutionary History of the Chymase Locus -a Locus Encoding Several of the Major Hematopoietic Serine Proteases

2021 ◽  
Vol 22 (20) ◽  
pp. 10975
Author(s):  
Srinivas Akula ◽  
Zhirong Fu ◽  
Sara Wernersson ◽  
Lars Hellman
Keyword(s):  
Mast Cell ◽  
T Cell ◽  
Serine Proteases ◽  
Phylogenetic Trees ◽  
Granzyme B ◽  
Large Family ◽  
Cathepsin G ◽  
Immune Functions ◽  
New Class ◽  
History Of

Several hematopoietic cells of the immune system store large amounts of proteases in cytoplasmic granules. The absolute majority of these proteases belong to the large family of chymotrypsin-related serine proteases. The chymase locus is one of four loci encoding these granule-associated serine proteases in mammals. The chymase locus encodes only four genes in primates, (1) the gene for a mast-cell-specific chymotryptic enzyme, the chymase; (2) a T-cell-expressed asp-ase, granzyme B; (3) a neutrophil-expressed chymotryptic enzyme, cathepsin G; and (4) a T-cell-expressed chymotryptic enzyme named granzyme H. Interestingly, this locus has experienced a number of quite dramatic expansions during mammalian evolution. This is illustrated by the very large number of functional protease genes found in the chymase locus of mice (15 genes) and rats (18 genes). A separate expansion has also occurred in ruminants, where we find a new class of protease genes, the duodenases, which are expressed in the intestinal region. In contrast, the opossum has only two functional genes in this locus, the mast cell (MC) chymase and granzyme B. This low number of genes may be the result of an inversion, which may have hindered unequal crossing over, a mechanism which may have been a major factor in the expansion within the rodent lineage. The chymase locus can be traced back to early tetrapods as genes that cluster with the mammalian genes in phylogenetic trees can be found in frogs, alligators and turtles, but appear to have been lost in birds. We here present the collected data concerning the evolution of this rapidly evolving locus, and how these changes in gene numbers and specificities may have affected the immune functions in the various tetrapod species.

Fibrin Networks Sustain Large Extensions Due to Unfolding Proteins

2010 ◽  
Author(s):  
Prashant K. Purohit
Keyword(s):  
Mechanical Properties ◽  
Protein Unfolding ◽  
Spatial Scales ◽  
Constitutive Models ◽  
Fibrin Clot ◽  
Matrix Proteins ◽  
Dramatic Decrease ◽  
Fiber Alignment ◽  
Fibrin Networks ◽  
Blood Clots

Blood clots and thrombi consist primarily of a mesh of branched fibers made of the protein fibrin. We show how these networks give rise to the remarkable extensibility and elasticity of blood clots by determining structural and mechanical properties of the clot at the network, fiber, and molecular levels. The force required to stretch a clot initially rises almost linearly and is accompanied by a dramatic decrease in the clot volume. These macroscopic changes are accompanied by fiber alignment and bundling following forced protein unfolding. We develop constitutive models to integrate observations at spatial scales that span six orders of magnitude and indicate that fibrin clot extensibility and shrinkage are both manifestations of protein unfolding, which is not apparent in other matrix proteins such as collagen.

Tripeptides with non-code amino acids as potential serine proteases inhibitors

2012 ◽  
Vol 28 (3) ◽  
pp. 639-643 ◽  
Author(s):  
Agnieszka Markowska ◽  
Magdalena Bruzgo ◽  
Arkadiusz Surażyński ◽  
Krystyna Midura-Nowaczek
Keyword(s):  
Amino Acids ◽  
Serine Proteases ◽  
Serine Proteases Inhibitors

Similarity study of serine proteases inhibitors

2006 ◽  
Vol 10 (1) ◽  
pp. 81-83 ◽  
Author(s):  
Gleb D. Perekhodtsev
Keyword(s):  
Serine Proteases ◽  
Serine Proteases Inhibitors

Fibrin Gel Induces the Migration of Smooth Muscle Cells from Rabbit Aortic Explants

1999 ◽  
Vol 82 (10) ◽  
pp. 1347-1352 ◽  
Author(s):  
Hideki Nomura ◽  
Akihisa Iguchi ◽  
W. Douglas Thompson ◽  
Elspeth Smith ◽  
Michitaka Naito
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Thrombin Inhibitors ◽  
Positive Staining ◽  
Αvβ3 Integrin ◽  
Major Step ◽  
Fibrin Gel ◽  
Vitro Assay ◽  
Fibrin Gels

SummaryA major step in the pathogenesis of atherosclerosis is the vectorial migration of smooth muscle cells (SMCs) from the arterial media into the intima. Although subcultured SMCs usually show synthetic phenotype, the behaviour of contractile SMCs may be crucial for the subsequent migration of the cells. In the present study, we utilized an in vitro assay system to evaluate the effects of fibrin gels on the migration of SMCs from explants taken from rabbit aorta. After cultured for 5-7 days in a serum-free condition, SMCs appeared from explants covered with fibrin gel. The cells were positive on immunostaining for SMC specific α-actin. No migration of SMCs from the control explants without fibrin gel was observed. Then the percentage of explants showing cell migration and the number of migrating cells increased with time. The migration of SMCs into fibrin gels was not dependent on the concentration of fibrinogen used for the preparation of fibrin gel in the range of 1.5-3 mg/ml. Variations of thrombin concentration in the range of 0.25-1.25 U/ml had no significant effect. However, there was less migration of SMCs with higher concentrations of thrombin. Thrombin inhibitors, hirudin and PPACK had no significant effect on the migration of SMCs. An RGD-containing peptide, GRGDS inhibited the migration of SMCs although a control peptide GRGES at the same concentration had no significant effect. A monoclonal antibody to αvβ3, LM609, completely inhibited the migration of SMCs from the explants, suggesting that αvβ3 integrin is involved in the migration of SMCs into fibrin gels. SMCs which migrated from the explants showed the positive staining with the monoclonal antibodies against SMC myosin heavy chain isoforms, SMemb, SM1 and SM2, suggesting that they are in an intermediate state changing from contractile to synthetic state. In conclusion, the present study showed that fibrin gel induces the migration of SMCs from explants into itself and the process may not need other growth factors or cytokines.

The Research Progress of Direct Thrombin Inhibitors

2020 ◽  
Vol 20 (16) ◽  
pp. 1574-1585
Author(s):  
Zhi-Gang Sun ◽  
Yang-Liu ◽  
Jin-Mai Zhang ◽  
Shi-Chang Cui ◽  
Zhi-Gang Zhang ◽  
...  
Keyword(s):  
High Specificity ◽  
Coagulation Factors ◽  
Fibrin Clot ◽  
Thrombin Inhibitors ◽  
Research Progress ◽  
Direct Thrombin Inhibitors ◽  
Design Synthesis ◽  
Anticoagulant Drug ◽  
Strong Action ◽  
Important Significance

Blood coagulation is the process of changing the blood from the flowing state to the gel state. It is an important part of the hemostatic function. Coagulation is a process by which a series of coagulation factors are sequentially activated, and finally thrombin is formed to form fibrin clot. Direct thrombin inhibitors are important anticoagulant drug. These drugs can selectively bind to the active site of thrombin, inhibit thrombin activity, have strong action and high specificity, and have important significance in the clinical treatment of thrombus diseases. Some of them come from natural products of animals or plants, and many of them have been applied in the clinic. The other part is derived from the design, synthesis and activity studies of small molecule inhibitors. This review discusses the progress of direct thrombin inhibitors in recent years.

Design and characterization of dipetacompinR10H, a dipetalogastin II-derived, classical competitive thrombin inhibitor

2007 ◽  
Vol 97 (01) ◽  
pp. 139-145
Author(s):  
Mercedes López ◽  
Goetz Nowak ◽  
Thomas Bitter
Keyword(s):  
Serine Proteases ◽  
Anticoagulant Activity ◽  
Tight Binding ◽  
Factor Xa ◽  
Thrombin Inhibitors ◽  
Thrombin Inhibitor ◽  
Coagulation Assays ◽  
Competitive Kinetics ◽  
Inhibition Of Thrombin

SummaryThe design of small chimeric thrombin inhibitors based on the structure of dipetalogastin II has been previously described. These proteins are effective inhibitors of thrombin showing slow binding or slow, tight-binding kinetics. We report here about dipetacompinR10H, a new dipetalogastin II-derived chimeric thrombin inhibitor, which exhibits classical competitive kinetics. The dissociation constant Ki of dipetacompinR10H was determined to be 17.1 ± 0.8 pM. In various coagulation assays it showed a comparable anticoagulant activity like r-hirudin and r-dipetalogastin II. DipetacompinR10H’s inhibition of thrombin was specific, since no inhibition of other serine proteases like factor Xa, plasmin, trypsin or chymotrypsin has been observed.

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