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Biochemical and Biophysical Research... Feb 2015The potent fibrinolytic enzyme, plasmin has numerous clinical applications for recannulizing vessels obstructed by thrombus. Despite its diminutive size, 91 kDa, success... (Comparative Study)
Comparative Study
The potent fibrinolytic enzyme, plasmin has numerous clinical applications for recannulizing vessels obstructed by thrombus. Despite its diminutive size, 91 kDa, success in the recombinant expression of this serine protease has been limited. For this reason, a truncated non-glycosylated plasmin variant was developed capable of being expressed and purified from E. coli. This mutated plasmin, known as δ-plasmin, eliminates four of the five kringle domains present on native plasmin, retaining only kringle 1 fused directly to the unmodified catalytic domain of plasmin. This study demonstrates that δ-plasmin exhibits similar kinetic characteristics to full length plasmin despite its heavily mutated form; KM = 268.78 ± 19.12, 324.90 ± 8.43 μM and Kcat = 770.48 ± 41.73, 778.21 ± 1.51 1/min for plasmin and δ-plasmin, respectively. A comparative analysis was also carried out to investigate the inhibitory effects of a range of benzamidine based small molecule inhibitors: benzamidine, p-aminobenzamidine, 4-carboxybenzamidine, 4-aminomethyl benzamidine, and pentamidine. All of the small molecule inhibitors, with the exception of unmodified benzamidine, demonstrated comparable competitive inhibition constants (Ki) for both plasmin and δ-plasmin ranging from Ki < 4 μM for pentamidine to Ki > 1000 μM in the case of aminomethyl benzamidine. This result further supports that δ-plasmin retains much of the same functionality as native plasmin despite its greatly reduced size and complexity. This study serves the purpose of demonstrating the tunable inhibition of plasmin and δ-plasmin with potential applications for the improved clinical delivery of δ-plasmin to treat various thrombi.
Topics: Antifibrinolytic Agents; Benzamidines; Fibrinolysin; Humans; Kinetics; Models, Molecular; Mutant Proteins; Plasminogen; Protein Conformation; Protein Structure, Tertiary; Recombinant Proteins; Structure-Activity Relationship
PubMed: 25576865
DOI: 10.1016/j.bbrc.2014.12.117 -
Molecules (Basel, Switzerland) Feb 2023Functionality of the fibrinolytic system is based on activity of its central enzyme, plasmin, responsible for the removal of fibrin clots. Besides the hemostasis,... (Review)
Review
Functionality of the fibrinolytic system is based on activity of its central enzyme, plasmin, responsible for the removal of fibrin clots. Besides the hemostasis, fibrinolytic proteins are also involved in many other physiological and pathological processes, including immune response, extracellular matrix degradation, cell migration, and tissue remodeling. Both the impaired and enhanced activity of fibrinolytic proteins may result in serious physiological consequences: prothrombotic state or excessive bleeding, respectively. However, current medicine offers very few options for treating fibrinolytic disorders, particularly in the case of plasmin inhibition. Although numerous attempts have been undertaken to identify natural or to develop engineered fibrinolytic system modulators, structural similarities within serine proteases of the hemostatic system and pleiotropic activity of fibrinolytic proteins constitute a serious problem in discovering anti- or profibrinolytic agents that could precisely affect the target molecules and reduce the risk of side effects. Therefore, this review aims to present a current knowledge of various classes of natural inhibitors and stimulators of the fibrinolytic system being well-defined low-molecular plant secondary metabolites or constituents of plant extracts as well as plant peptides. This work also discusses obstacles caused by low specificity of most of natural compounds and, hence, outlines recent trends in studies aimed at finding more efficient modulators of plasmin activity, including investigation of modifications of natural pharmacophore templates.
Topics: Fibrinolysin; Fibrinolysis; Serine Endopeptidases; Hemostasis; Phytochemicals
PubMed: 36838662
DOI: 10.3390/molecules28041677 -
Journal of Neuroscience Research Mar 2021Many coagulation factor proteases are increased in the brain during ischemic stroke. One of these proteases is plasmin. In this study we established a novel method for...
Many coagulation factor proteases are increased in the brain during ischemic stroke. One of these proteases is plasmin. In this study we established a novel method for direct quantitative measurement of plasmin activity in male mouse brain slices using a sensitive fluorescent substrate in the presence of specific protease inhibitors. In both the ischemic and contralateral hemispheres, plasmin activity increased 3, 6, and 24 hr following stroke in comparison to healthy mice (F(3, 72) = 39.5, p < 0.0001, repeated measures ANOVA) after the induction of permanent middle cerebral artery occlusion (PMCAo). Plasmin activity was higher in the ischemic hemisphere (F(1,36) = 9.1, p = 0.005) and there was a significant interaction between time and ischemic hemisphere (F(3,36) = 4.4, p = 0.009). Plasmin activity was correlated with infarct volume (R = 0.5289, p = 0.0009 by Spearman). The specificity of the assay was verified utilizing tissue-type plasminogen activator (tPA)-deficient mice which, as expected, had significantly lower levels of plasmin 24 hr following ischemia compared to wild-type mice (ischemic (0.6 ± 0.23 and 1.94 ± 0.5, respectively), p = 0.049 and contralateral hemispheres (0.13 ± 0.14 and 0.75 ± 0.10, respectively), p = 0.018 by t test). There is a time-dependent increase in plasmin levels and an association of higher levels of plasmin with larger infarct volumes in an experimental stroke model. This suggests caution in the use of recombinant tPA (rtPA) and that plasmin inhibition in the brain may be a therapeutic target in acute ischemic stroke.
Topics: Animals; Brain; Brain Infarction; Enzyme Assays; Fibrinolysin; Infarction, Middle Cerebral Artery; Ischemic Stroke; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Animal; Tissue Plasminogen Activator
PubMed: 33296953
DOI: 10.1002/jnr.24764 -
Translational Vision Science &... Apr 2023We sought to evaluate the efficacy and safety of plasmin injection in the capsular bag during the cataract operation for the prevention of posterior capsule...
PURPOSE
We sought to evaluate the efficacy and safety of plasmin injection in the capsular bag during the cataract operation for the prevention of posterior capsule opacification.
METHODS
Thirty-seven anterior capsular flaps taken from phacoemulsification surgery were immersed in either 1 µg/mL plasmin (plasmin group, n = 27) or phosphate-buffered saline (control group, n = 10) for 2 minutes and photographed after fixation and nuclear staining to compare the numbers of residual lens epithelial cells. In the animal experiments, the plasmin solution was injected into the capsular bag and remained for 5 minutes during hydrodissection or after lens extraction. The degree of posterior capsular opacity of the rabbits at 2 months were photographed by slit lamp biomicroscopy. In HLE-B3 cell culture, the cell detachment rate, proliferation, and apoptosis after the plasmin digestion were analyzed.
RESULTS
The residual lens epithelial cell numbers on the capsule after plasmin treatment were 168 ± 190.7/mm2 in the 1 µg/mL plasmin group, which was significantly lower than that of the control (1012 ± 798.8/mm2; P < 0.0001). In a rabbit model, the treatment of plasmin resulted in a significantly clearer posterior capsule compared with that of the control group at 2 months postoperatively.
CONCLUSIONS
This study suggested that plasmin injection can induce effective lens epithelial cell detachment, which could be a promising adjunctive treatment to further improve the success rate in posterior capsule opacification prevention.
TRANSLATIONAL RELEVANCE
Plasmin injection for lens epithelial cell detachment could significantly decrease the number of residual lens epithelial cells. This approach could be a promising treatment incorporating the current treatment approach to further improve the success rate in posterior capsule opacification prevention.
Topics: Animals; Rabbits; Capsule Opacification; Fibrinolysin; Lens Capsule, Crystalline; Epithelial Cells; Phacoemulsification
PubMed: 37074731
DOI: 10.1167/tvst.12.4.23 -
Blood Coagulation & Fibrinolysis : An... Sep 2022Disturbances in the balance between coagulation, anticoagulation and fibrinolysis may lead to thrombosis or haemorrhage. Simultaneous assessments of thrombin and plasmin...
Disturbances in the balance between coagulation, anticoagulation and fibrinolysis may lead to thrombosis or haemorrhage. Simultaneous assessments of thrombin and plasmin facilitate overall understandings of pathological haemostasis, especially for thrombophilia. Here, we characterized coagulation-fibrinolysis potentials in plasmas with thrombophilia using anticoagulants-mediated thrombin-plasmin generation assay (T/P-GA). T/P-GA was initiated by adding tissue factor, tissue-type plasminogen activator and anticoagulants [recombinant-thrombomodulin (rTM), activated protein (P)C (APC) and antithrombin (AT)], followed by simultaneous thrombin generation and plasma generation monitoring. Patients' plasmas with PC-deficiency (PC-def), PS-deficiency (PS-def), AT-deficiency (AT-def), factor VLeiden (FVL) and antiphospholipid syndrome (APS) were evaluated. A ratio of peak-thrombin (or peak-plasmin) with and without anticoagulants was calculated as anticoagulants (+)/anticoagulants (-). First, TG, in rTM-mediated, PC-def, PS-def and FVL showed higher peak-thrombin ratios than the controls, whereas AT-def and APS exhibited no differences from the controls. In APC-mediated, PC-def, PS-def and AT-def showed low peak-thrombin ratios, similar to the controls, but immune-depleted PS-def (<1%) showed the higher ratio than the controls. FVL and APS showed higher peak-thrombin ratios than the controls. In AT-mediated, peak-thrombin ratios in PS-def, PC-def and APS were lower than in controls, but those in AT-def and FVL was not significantly different from the controls. Second, PG, in rTM-mediated, all thrombophilia plasmas showed low peak-plasmin ratios (∼0.5), but no significant difference was observed, relative to the controls. In APC and AT-mediated, peak-plasmin ratios in thrombophilia-related plasmas were similar to the controls (∼1.0). Anticoagulants-mediated T/P-GA may classify thrombin generation characteristics in thrombophilia-related plasmas upon adding anticoagulants.
Topics: Anticoagulants; Antiphospholipid Syndrome; Antithrombins; Blood Coagulation Tests; Fibrinolysin; Humans; Thrombin; Thrombophilia
PubMed: 35981254
DOI: 10.1097/MBC.0000000000001148 -
Food Research International (Ottawa,... Mar 2023Plasmin plays an important role in casein hydrolysis during cheese ripening, which may influence the properties of the casein network and the texture of the final...
Plasmin plays an important role in casein hydrolysis during cheese ripening, which may influence the properties of the casein network and the texture of the final product. In view of this, the relation between plasmin-induced casein hydrolysis and textural changes of cheese during ripening was investigated in this study. Four batches of model cheese with different concentrations of added plasmin (0, 0.4, 0.6 and 1.0 μL/g milk) were prepared, and were stored for 12 weeks at 16 °C. During this period, plasmin activity, casein hydrolysis, textural properties and other compositional characteristics (pH, dry matter) were determined. Our results show that the addition of plasmin had significant effect on both the degree and the pattern of proteolysis. As a result, cheeses with different plasmin content showed different textural properties. With increased plasmin concentration, Young's modulus, hardness, resilience and cohesion decreased, while brittleness increased. All textural properties showed linear relations with the degree of casein hydrolysis, and logarithmic relations with the percentage of intact casein fractions. At the beginning of ripening, only slight changes in textural properties were found, although a substantial part (40-60 %) of the casein fractions was already been broken down. When ripening progressed, ongoing proteolysis significantly weakened the protein network and consequently led to noticeable textural changes. Model cheeses became softer, more brittle and less elastic. The knowledge gained from this study provide new insights in the changes of different textural parameters of model cheese. This will help to optimize the existing products and create new ones.
Topics: Hydrolysis; Caseins; Fibrinolysin; Cheese
PubMed: 36869466
DOI: 10.1016/j.foodres.2022.112421 -
The Cochrane Database of Systematic... Oct 2017Symptomatic vitreomacular adhesion (sVMA) is a recognised cause of visual loss and by tradition has been managed by pars plana vitrectomy (PPV). A less invasive... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Symptomatic vitreomacular adhesion (sVMA) is a recognised cause of visual loss and by tradition has been managed by pars plana vitrectomy (PPV). A less invasive alternative to surgery in some people is enzymatic vitreolysis, using an intravitreal injection of ocriplasmin.
OBJECTIVES
To assess the efficacy and safety of ocriplasmin compared to no treatment, sham or placebo for the treatment of sVMA.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 1), MEDLINE Ovid (1946 to 24 February 2017), Embase Ovid (1947 to 24 February 2017), PubMed (1946 to 24 February 2017), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 24 February 2017, ClinicalTrials.gov (www.clinicaltrials.gov); searched 24 February 2017 and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 24 February 2017. We did not use any date or language restrictions in the electronic searches for trials.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) of people with sVMA. The intervention was intravitreal ocriplasmin 125 μg injection, and this was compared to placebo or sham injection (control). Placebo was defined as a single intravitreal injection of 0.10 mL placebo with identical drug vehicle diluted with saline. A sham injection was defined as the syringe hub or blunt needle touching the conjunctiva to simulate an injection.
DATA COLLECTION AND ANALYSIS
Two authors independently selected relevant trials, assessed methodological quality and extracted data. We graded the certainty of the evidence using the GRADE approach.
MAIN RESULTS
This review included four RCTs conducted in Europe and the USA with a total of 932 eyes of 932 participants. Participants were 18 to 97 years of age, with evidence of focal vitreomacular adhesion (VMA) on optical coherence tomography (OCT) imaging, with a best corrected visual acuity (BCVA) of 20/25 or worse in the study eye and 20/400 or better in the fellow eye. The interventions compared were intravitreal ocriplasmin versus sham (two RCTs) or placebo (two RCTs) injection. Both sham and placebo injection were classified as the control group. The main outcome measures were assessed at 28 days and six months. Overall, we judged the studies to have a low or unclear risk of bias. All four RCTs were sponsored by the manufacturers of ocriplasmin.Compared with control, ocriplasmin treatment was more likely to result in VMA release within 28 days (risk ratio (RR) 3.46, 95% confidence interval (CI) 2.00 to 6.00; 859 eyes, 4 RCTs, high-certainty evidence). Approximately 97/1000 eyes will have VMA release within 28 days without treatment. An additional 237 eyes will have VMA release within 28 days for every 1000 eyes treated with ocriplasmin (95% CI 96 more to 482 more).Treatment with ocriplasmin was also more likely to result in macular hole closure (RR 2.87, 95% CI 1.50 to 5.51; 229 eyes, 3 RCTs, high-certainty evidence). Approximately 123/1000 eyes with macular holes will have closure with no treatment. An additional 231 eyes will have macular hole closure for every 1000 eyes treated with ocriplasmin (95% CI 62 more to 556 more).Eyes receiving ocriplasmin were also more likely to have complete posterior vitreous detachment (PVD) within 28 days (RR 2.94, 95% CI 1.39 to 6.24; 689 eyes, 3 RCTs, high-certainty evidence). Approximately 40/1000 eyes will have complete PVD within 28 days without treatment. An additional 78 eyes will have complete PVD within 28 days for every 1000 eyes treated with ocriplasmin (95% CI 16 more to 210 more).Eyes receiving ocriplasmin were more likely to achieve 3-line or greater improvement in BCVA at six months (RR 1.95, 95% CI 1.07 to 3.53; 674 eyes, 3 RCTs, moderate-certainty evidence). Approximately 61/1000 eyes will have a 3-line or greater improvement in BCVA at six months without treatment. An additional 58 eyes will have 3-line or greater improvement in BCVA at six months for every 1000 eyes treated with ocriplasmin (95% CI 9 more to 154 more).Receiving ocriplasmin also reduced the requirement for vitrectomy at six months (RR 0.67, 95% CI 0.50 to 0.91; 689 eyes, 3 RCTs, moderate-certainty evidence). Approximately 265/1000 eyes will require vitrectomy at six months without treatment and 87 fewer eyes will require vitrectomy for every 1000 eyes treated with ocriplasmin (95% CI 24 fewer to 132 fewer).Treatment with ocriplasmin resulted in a greater improvement in validated Visual Function Questionnaire form score at six months (mean improvement difference 2.7 points, 95% CI 0.8 to 4.6; 652 eyes, 2 RCTs, moderate-certainty evidence).Eyes receiving ocriplasmin were more likely to have an adverse event (RR 1.22, 95% CI 1.09 to 1.37, 909 eyes, 4 RCTs, moderate-certainty evidence). Approximately 571/1000 eyes will have an adverse event with sham or placebo injection and 106 more eyes will have an adverse event for every 1000 eyes treated with ocriplasmin (95% CI 52 more to 212 more).
AUTHORS' CONCLUSIONS
Evidence from a limited number of RCTs suggests that ocriplasmin is useful in the treatment of sVMA. However, up to 20% of eyes treated with ocriplasmin will still require additional treatment with PPV within six months. There were more ocular adverse events in eyes treated with ocriplasmin than control (sham or placebo injection) treatment. Many of these adverse events, particularly vitreous floaters and photopsia, are known to be associated with posterior vitreous detachment. At present however, there is minimal published long-term safety data on eyes treated with ocriplasmin. Further large RCTs comparing ocriplasmin with other management options for sVMA would be beneficial.
Topics: Adult; Aged; Aged, 80 and over; Fibrinolysin; Fibrinolytic Agents; Humans; Intravitreal Injections; Middle Aged; Peptide Fragments; Randomized Controlled Trials as Topic; Retinal Diseases; Time Factors; Tissue Adhesions; Visual Acuity; Vitrectomy; Vitreous Body; Vitreous Detachment
PubMed: 29040800
DOI: 10.1002/14651858.CD011874.pub2 -
Proceedings of the National Academy of... Feb 2023Triglyceride (TG) metabolism is highly regulated by angiopoietin-like protein (ANGPTL) family members [Y. Q. Chen , , 1203-1220 (2020)]. During feeding, ANGPTL8 forms...
Triglyceride (TG) metabolism is highly regulated by angiopoietin-like protein (ANGPTL) family members [Y. Q. Chen , , 1203-1220 (2020)]. During feeding, ANGPTL8 forms complexes with the fibrinogen-like domain-containing protein ANGPTL4 in adipose tissue to decrease ANGPTL3/8- and ANGPTL4-mediated lipoprotein lipase (LPL)-inhibitory activity and promote TG hydrolysis and fatty acid (FA) uptake. The ANGPTL4/8 complex, however, tightly binds LPL and partially inhibits it in vitro. To try to reconcile the in vivo and in vitro data on ANGPTL4/8, we aimed to find novel binding partners of ANGPTL4/8. To that end, we performed pulldown experiments and found that ANGPTL4/8 bound both tissue plasminogen activator (tPA) and plasminogen, the precursor of the fibrinolytic enzyme plasmin. Remarkably, ANGPTL4/8 enhanced tPA activation of plasminogen to generate plasmin in a manner like that observed with fibrin, while minimal plasmin generation was observed with ANGPTL4 alone. The addition of tPA and plasminogen to LPL-bound ANGPTL4/8 caused rapid, complete ANGPTL4/8 cleavage and increased LPL activity. Restoration of LPL activity in the presence of ANGPTL4/8 was also achieved with plasmin but was blocked when catalytically inactive plasminogen (S760A) was added to tPA or when plasminogen activator inhibitor-1 was added to tPA + plasminogen, indicating that conversion of plasminogen to plasmin was essential. Together, these results suggest that LPL-bound ANGPTL4/8 mimics fibrin to recruit tPA and plasminogen to generate plasmin, which then cleaves ANGPTL4/8, enabling LPL activity to be increased. Our observations thus reveal a unique link between the ANGPTL4/8 complex and plasmin generation.
Topics: Angiopoietin-Like Protein 4; Angiopoietin-Like Protein 8; Fibrinolysin; Lipoprotein Lipase; Plasminogen; Serine Proteases; Tissue Plasminogen Activator; Triglycerides; Humans
PubMed: 36763533
DOI: 10.1073/pnas.2214081120 -
Future Microbiology 2015Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion... (Review)
Review
Cryptococcus demonstrates predilection for invasion of the brain, but the mechanism by which Cryptococcus crosses the blood-brain barrier (BBB) to cause brain invasion is largely unknown. In order for Cryptococcus to cross the BBB, there must be a way to either cross human brain microvascular endothelial cells, which are the main constitute of the BBB, or go in between tight junctions. Recent evidence of human brain microvascular endothelial cell responses to transcellular brain invasions includes membrane rearrangements, intracellular signaling pathways and cytoskeletal activations. Several Cryptococcal genes related to the traversal of BBB have been identified, including CPS1, ITR1a, ITR3c, PLB1, MPR1, FNX1 and RUB1. In addition, Cryptococcus neoformans-derived microvesicles may contribute to cryptococcal brain invasion. Paracellularly, Cryptococcus may traverse across BBB using either routes utilizing plasmin, ammonia or macrophages in a Trojan horse mechanism.
Topics: Ammonia; Blood-Brain Barrier; Brain; Cryptococcosis; Cryptococcus; Endothelial Cells; Fibrinolysin; Humans; Hyaluronan Receptors; Macrophages
PubMed: 26437710
DOI: 10.2217/fmb.15.83 -
Veterinary Microbiology Jul 2015The plasminogen (Plg) system plays an important homeostatic role in the degradation of fibrin clots, extracellular matrices and tissue barriers important for cellular... (Review)
Review
The plasminogen (Plg) system plays an important homeostatic role in the degradation of fibrin clots, extracellular matrices and tissue barriers important for cellular migration, as well as the promotion of neurotransmitter release. Plg circulates in plasma at physiologically high concentrations (150-200μg ml(-1)) as an inactive proenzyme. Proteins enriched in lysine and other positively charged residues (histidine and arginine) as well as glycosaminoglycans and gangliosides bind Plg. The binding interaction initiates a structural adjustment to the bound Plg that facilitates cleavage by proteases (plasminogen activators tPA and uPA) that activate Plg to the active serine protease plasmin. Both pathogenic and commensal bacteria capture Plg onto their cell surface and promote its conversion to plasmin. Many microbial Plg-binding proteins have been described underpinning the importance this process plays in how bacteria interact with their hosts. Bacteria exploit the proteolytic capabilities of plasmin by (i) targeting the mammalian fibrinolytic system and degrading fibrin clots, (ii) remodeling the extracellular matrix and generating bioactive cleavage fragments of the ECM that influence signaling pathways, (iii) activating matrix metalloproteinases that assist in the destruction of tissue barriers and promote microbial metastasis and (iv) destroying immune effector molecules. There has been little focus on the exploitation of the fibrinolytic system by veterinary pathogens. Here we describe several pathogens of veterinary significance that possess adhesins that bind plasmin(ogen) onto their cell surface and promote its activation to plasmin. Cumulative data suggests that these attributes provide pathogenic and commensal bacteria with a means to colonize and persist within the host environment.
Topics: Adhesins, Bacterial; Animals; Bacteria; Enzyme Precursors; Fibrinolysin; Fibrinolysis; Plasminogen
PubMed: 25937317
DOI: 10.1016/j.vetmic.2015.04.008