A Novel Leptospira interrogans Protein LIC13086 Inhibits Fibrin Clot Formation and Interacts With Host Components

Leptospirosis is a neglected zoonosis, caused by pathogenic spirochetes bacteria of the genus Leptospira. The molecular mechanisms of leptospirosis infection are complex, and it is becoming clear that leptospires express several functionally redundant proteins to invade, disseminate, and escape the host’s immune response. Here, we describe a novel leptospiral protein encoded by the gene LIC13086 as an outer membrane protein. The recombinant protein LIC13086 can interact with the extracellular matrix component laminin and bind plasminogen, thus possibly participating during the adhesion process and dissemination. Also, by interacting with fibrinogen and plasma fibronectin, the protein LIC13086 probably has an inhibitory effect in the fibrin clot formation during the infection process. The newly characterized protein can also bind molecules of the complement system and the regulator C4BP and, thus, might have a role in the evasion mechanism of Leptospira. Taken together, our results suggest that the protein LIC13086 may have a multifunctional role in leptospiral pathogenesis, participating in host invasion, dissemination, and immune evasion processes.

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4-Thio-deoxyuridylate-modified thrombin aptamer and its inhibitory effect on fibrin clot formation, platelet aggregation and thrombus growth on subendothelial matrix

Journal of Thrombosis and Haemostasis ◽

10.1111/j.1538-7836.2008.03106.x ◽

2008 ◽

Vol 6 (10) ◽

pp. 1764-1771 ◽

Cited By ~ 31

Author(s):

S. MENDELBOUM RAVIV ◽

A. HORVÁTH ◽

J. ARADI ◽

Z. BAGOLY ◽

F. FAZAKAS ◽

...

Keyword(s):

Platelet Aggregation ◽

Inhibitory Effect ◽

Fibrin Clot ◽

Clot Formation ◽

Subendothelial Matrix

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Properties of Fibrinogen Cleaved by Jararhagin, a Metalloproteinase from the Venom of Bothrops jararaca

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648847 ◽

1994 ◽

Vol 72 (02) ◽

pp. 244-249 ◽

Cited By ~ 48

Author(s):

Aura S Kamiguti ◽

Joseph R Slupsky ◽

Mirko Zuzel ◽

Charles R M Hay

Keyword(s):

Platelet Aggregation ◽

Platelet Function ◽

Fibrin Clot ◽

Clot Formation ◽

Human Fibrinogen ◽

Activated Platelets ◽

Bothrops Jararaca ◽

Platelet Binding ◽

Fibrin Monomers ◽

Fibrinogen Molecule

SummaryHaemorrhagic metalloproteinases from Bothrops jararaca and other venoms degrade vessel-wall and plasma proteins involved in platelet plug and fibrin clot formation. These enzymes also cause proteolytic digestion of fibrinogen which has been suggested to cause defective platelet function. Fibrinogen degradation by jararhagin, a metalloproteinase from B. jararaca, and the effect of jararhagin fibrinogenolysis on both platelet aggregation and fibrin clot formation were investigated. Jararhagin was found to cleave human fibrinogen in the C-terminal region of the Aα-chain giving rise to a 285-290 kDa fibrinogen molecule lacking the Aα-chain RGD 572-574 platelet-binding site. Platelet binding and aggregation of ADP-activated platelets is unaffected by this modification. This indicates that the lost site is not essential for platelet aggregation, and that the remaining platelet binding sites located in the N-terminal portion of Aα chains (RGD 95-97) and the C-terminal of γ chains (dodecapeptide 400-411) are unaffected by jararhagin-digestion of fibrinogen. Fibrin clot formation with thrombin of this remnant fibrinogen molecule was defective, with poor polymerization of fibrin monomers but normal release of FPA. The abnormal polymerization could be explained by the loss of one of the two complementary polymerization sites required for side-by-side association of fibrin protofibrils. Jararhagin-induced inhibition of platelet function, an important cause of haemorrhage in envenomed patients, is not caused by proteolysis of fibrinogen, as had been thought, and the mechanism remains to be elucidated.

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Fibrin Formation: The Role of the Fibrinogen-Fibrin Monomer Complex

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648007 ◽

1976 ◽

Vol 36 (01) ◽

pp. 037-048 ◽

Cited By ~ 49

Author(s):

Eric P. Brass ◽

Walter B. Forman ◽

Robert V. Edwards ◽

Olgierd Lindan

Keyword(s):

Particle Size ◽

Induction Period ◽

Fibrin Clot ◽

Clot Formation ◽

Appreciable Amount ◽

Buffer System ◽

Homeostatic Mechanism ◽

Fibrin Formation ◽

Fibrin Monomer

SummaryThe process of fibrin formation using highly purified fibrinogen and thrombin was studied using laser fluctuation spectroscopy, a method that rapidly determines particle size in a solution. Two periods in fibrin clot formation were noted: an induction period during which no fibrin polymerization occurred and a period of rapid increase in particle size. Direct measurement of fibrin monomer polymerization and fibrinopeptide release showed no evidence of an induction period. These observations were best explained by a kinetic model for fibrin clot formation incorporating a reversible fibrinogen-fibrin monomer complex. In this model, the complex serves as a buffer system during the earliest phase of fibrin formation. This prevents the accumulation of free polymerizable fibrin monomer until an appreciable amount of fibrinogen has reacted with thrombin, at which point the fibrin monomer level rises rapidly and polymerization proceeds. Clinically, the complex may be a homeostatic mechanism preventing pathological clotting during periods of elevated fibrinogen.

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Effects of Prostaglandins, Derivatives of Cyclic 3':5'-AMP, Theophylline, Cholinergic Agents and Colchicine on Clot Retraction in Dilute Platelet-Rich Plasma and Gel-Separated Platelet Test Systems

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651477 ◽

1977 ◽

Vol 38 (02) ◽

pp. 0420-0428 ◽

Cited By ~ 1

Author(s):

J. L Moake ◽

P. L Cimo ◽

K Widmer ◽

D. M Peterson ◽

J. R Gum

Keyword(s):

Platelet Rich Plasma ◽

Inhibitory Effect ◽

Fibrin Clot ◽

Serotonin Release ◽

Dibutyryl Camp ◽

Clot Retraction ◽

Dilute Suspensions ◽

Cholinergic Agents ◽

Camp Levels ◽

Derivatives Of

SummaryIn dilute suspensions of platelet-rich plasma (PRP) or gel-separated platelets (GSP), dibutyryl-cAMP (DBcAMP) and monobutyryl-cAMP inhibited platelet-mediated fibrin clot retraction in concentrations of 2–3 × 10–6M, with complete inhibition at 1–3 × 10–4M. Prostaglandin E1 (PGE1), which inhibited fibrin clot retraction in concentrations greater than 1.5–3 × 10–8M, was a more effective inhibitor than either PGE2 or PGF2α. In the presence of theophylline (10–4M), concentrations of DBcAMP, PGE1 PGE2 and PGF2α necessary to inhibit fibrin clot retraction were reduced 50-fold for DBcAMP and 2.5 to 20-fold for the prostaglandins. In dilute PRP or GSP, inhibition of fibrin clot retraction does not result from inhibition of thrombin-induced platelet aggregation. Thus, compounds which increase platelet cAMP levels result in the inhibition of platelet-mediated fibrin clot retraction, and this inhibitory effect may be mediated, at least in part, through suppression of platelet contractility. Cyclic GMP, dibutyryl-cGMP and carbamylcholine-Cl (which stimulates guanylate cyclase) did not influence fibrin clot retraction, and did not prevent inhibition of fibrin clot retraction by DBcAMP and PGE?. Colchicine, in concentrations known to disrupt platelet microtubules (2.5 × 10–6M to 2.5 x 10–3M), had little inhibitory effect on either fibrin clot retraction or platelet (3H)-serotonin release.

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Molecular Mechanisms of the Inhibitory Effects of Bupivacaine, Levobupivacaine, and Ropivacaine on Sarcolemmal Adenosine Triphosphate–sensitive Potassium Channels in the Cardiovascular System

Anesthesiology ◽

10.1097/00000542-200408000-00020 ◽

2004 ◽

Vol 101 (2) ◽

pp. 390-398 ◽

Cited By ~ 24

Author(s):

Takashi Kawano ◽

Shuzo Oshita ◽

Akira Takahashi ◽

Yasuo Tsutsumi ◽

Yoshinobu Tomiyama ◽

...

Keyword(s):

Cardiovascular System ◽

Adenosine Triphosphate ◽

Local Anesthetics ◽

Molecular Mechanisms ◽

Transmembrane Domain ◽

Katp Channels ◽

Inhibitory Effect ◽

Amino Acid Residues ◽

Sulfonylurea Receptor ◽

Inhibitory Effects

Background Sarcolemmal adenosine triphosphate-sensitive potassium (KATP) channels in the cardiovascular system may be involved in bupivacaine-induced cardiovascular toxicity. The authors investigated the effects of local anesthetics on the activity of reconstituted KATP channels encoded by inwardly rectifying potassium channel (Kir6.0) and sulfonylurea receptor (SUR) subunits. Methods The authors used an inside-out patch clamp configuration to investigate the effects of bupivacaine, levobupivacaine, and ropivacaine on the activity of reconstituted KATP channels expressed in COS-7 cells and containing wild-type, mutant, or chimeric SURs. Results Bupivacaine inhibited the activities of cardiac KATP channels (IC50 = 52 microm) stereoselectively (levobupivacaine, IC50 = 168 microm; ropivacaine, IC50 = 249 microm). Local anesthetics also inhibited the activities of channels formed by the truncated isoform of Kir6.2 (Kir6.2 delta C36) stereoselectively. Mutations in the cytosolic end of the second transmembrane domain of Kir6.2 markedly decreased both the local anesthetics' affinity and stereoselectivity. The local anesthetics blocked cardiac KATP channels with approximately eightfold higher potency than vascular KATP channels; the potency depended on the SUR subtype. The 42 amino acid residues at the C-terminal tail of SUR2A, but not SUR1 or SUR2B, enhanced the inhibitory effect of bupivacaine on the Kir6.0 subunit. Conclusions Inhibitory effects of local anesthetics on KATP channels in the cardiovascular system are (1) stereoselective: bupivacaine was more potent than levobupivacaine and ropivacaine; and (2) tissue specific: local anesthetics blocked cardiac KATP channels more potently than vascular KATP channels, via the intracellular pore mouth of the Kir6.0 subunit and the 42 amino acids at the C-terminal tail of the SUR2A subunit, respectively.

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Predictive value of C-reactive protein for radiographic spinal progression in axial spondyloarthritis in dependence on genetic determinants of fibrin clot formation and fibrinolysis

RMD Open ◽

10.1136/rmdopen-2021-001751 ◽

2021 ◽

Vol 7 (2) ◽

pp. e001751

Author(s):

Berthold Hoppe ◽

Christian Schwedler ◽

Hildrun Haibel ◽

Maryna Verba ◽

Fabian Proft ◽

...

Keyword(s):

Predictive Value ◽

Axial Spondyloarthritis ◽

Fibrin Clot ◽

Clot Formation ◽

Genetic Determinants ◽

C Reactive Protein ◽

Inception Cohort ◽

Reactive Protein ◽

A Subunit ◽

Fibrin Clots

ObjectiveGenetic determinants of fibrin clot formation and fibrinolysis have an impact on local and systemic inflammatory response. The aim of the present study was to assess whether coagulation-related genotypes affect the predictive value of C-reactive protein (CRP) in regards of radiographic spinal progression in axial spondyloarthritis (axSpA).MethodsTwo hundred and eight patients with axSpA from the German Spondyloarthritis Inception Cohort were characterised for genotypes of α-fibrinogen, β-fibrinogen (FGB) and γ-fibrinogen, factor XIII A-subunit (F13A) and α2-antiplasmin (A2AP). The relation between CRP levels and radiographic spinal progression defined as worsening of the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) by ≥2 points over 2 years was assessed in dependence on the respective genetic background in logistic regression analyses.ResultsOverall, CRP was associated with mSASSS progression ≥2 points: time-averaged CRP ≥10 mg/L, OR: 3.32, 95% CI 1.35 to 8.13. After stratification for coagulation-related genotypes, CRP was strongly associated with mSASSS progression in individuals predisposed to form loose, fibrinolysis-susceptible fibrin clots (FGB rs1800790GG, OR: 6.86, 95% CI 2.08 to 22.6; A2AP 6Trp, OR: 5.86, 95% CI 1.63 to 21.0; F13A 34Leu, OR: 8.72, 95% CI 1.69 to 45.1), while in genotypes predisposing to stable fibrin clots, the association was absent or weak (FGB rs1800790A, OR: 0.83, 95% CI 0.14 to 4.84; A2AP 6Arg/Arg, OR: 1.47, 95% CI 0.35 to 6.19; F13A 34Val/Val, OR: 1.72, 95% CI 0.52 to 5.71).ConclusionsElevated CRP levels seem to be clearly associated with radiographic spinal progression only if patients are predisposed for loose fibrin clots with high susceptibility to fibrinolysis.

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Fibrin Clot Formation and Lysis in Plasma

Methods and Protocols ◽

10.3390/mps3040067 ◽

2020 ◽

Vol 3 (4) ◽

pp. 67

Author(s):

Julie Brogaard Larsen ◽

Anne-Mette Hvas

Keyword(s):

Fibrinolytic Activity ◽

Research Laboratory ◽

Ex Vivo ◽

Fibrin Clot ◽

Clot Formation ◽

Coagulation Assays ◽

Fibrin Formation ◽

Over Time ◽

Routine Coagulation

Disturbance in the balance between fibrin formation and fibrinolysis can lead to either bleeding or thrombosis; however, our current routine coagulation assays are not sensitive to altered fibrinolysis. The clot formation and lysis assay is a dynamic plasma-based analysis that assesses the patient’s capacity for fibrin formation and fibrinolysis by adding an activator of coagulation as well as fibrinolysis to plasma and measuring ex vivo fibrin clot formation and breakdown over time. This assay provides detailed information on the fibrinolytic activity but is currently used for research only, as the assay is prone to inter-laboratory variation and as it demands experienced laboratory technicians as well as specialized personnel to validate and interpret the results. Here, we describe a protocol for the clot formation and lysis assay used at our research laboratory.

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The Inhibitory Effect of a Novel Polypeptide Fraction fromArca subcrenataon Cancer-Related Inflammation in Human Cervical Cancer HeLa Cells

The Scientific World JOURNAL ◽

10.1155/2014/768938 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Yu Wu ◽

Xianjing Hu ◽

Liyan Song ◽

Jianhua Zhu ◽

Rongmin Yu

Keyword(s):

Cervical Cancer ◽

Hela Cells ◽

Molecular Mechanisms ◽

Tumor Development ◽

Basic Research ◽

Inhibitory Effect ◽

Fishery Resource ◽

Proinflammatory Mediators ◽

Raw264.7 Macrophage ◽

Human Cervical Cancer

Inflammation is known to be closely associated with the development of cancer. The study was launched in human cervical cancer HeLa cells to investigate the antitumor and anti-inflammatory effects of P2, a marine polypeptide fraction from an important fishery resourceArca subcrenata. The basic research showed that P2 could suppress the production of nitric oxide in LPS-induced RAW264.7 macrophage cells as well as the secretion of inflammatory cytokines IL-6 and TNF-αin human cervical cancer HeLa cells. For the molecular mechanisms, P2 was shown to downregulate the gene expression of proinflammatory cytokines IL-6 and IL-8 and to inhibit the COX-2 and iNOS-related pathways in HeLa cells. In consequence, P2 might inhibit tumor development by blocking the interaction between tumor microenvironment and proinflammatory mediators. All findings indicate that P2 possesses the potential to be developed as a novel agent for cancer therapy.

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