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Diwan D, Usmani Z, Sharma M, Nelson JW, Thakur VK, Christie G, Molina G, Gupta VK. Thrombolytic Enzymes of Microbial Origin: A Review. Int J Mol Sci 2021; 22:10468. [PMID: 34638809 PMCID: PMC8508633 DOI: 10.3390/ijms221910468] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 01/10/2023] Open
Abstract
Enzyme therapies are attracting significant attention as thrombolytic drugs during the current scenario owing to their great affinity, specificity, catalytic activity, and stability. Among various sources, the application of microbial-derived thrombolytic and fibrinolytic enzymes to prevent and treat vascular occlusion is promising due to their advantageous cost-benefit ratio and large-scale production. Thrombotic complications such as stroke, myocardial infarction, pulmonary embolism, deep venous thrombosis, and peripheral occlusive diseases resulting from blood vessel blockage are the major cause of poor prognosis and mortality. Given the ability of microbial thrombolytic enzymes to dissolve blood clots and prevent any adverse effects, their use as a potential thrombolytic therapy has attracted great interest. A better understanding of the hemostasis and fibrinolytic system may aid in improving the efficacy and safety of this treatment approach over classical thrombolytic agents. Here, we concisely discuss the physiological mechanism of thrombus formation, thrombo-, and fibrinolysis, thrombolytic and fibrinolytic agents isolated from bacteria, fungi, and algae along with their mode of action and the potential application of microbial enzymes in thrombosis therapy.
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Affiliation(s)
- Deepti Diwan
- Department of Neurosurgery, Washington University School of Medicine, Saint Louis, MO 63110, USA; (D.D.); (J.W.N.)
| | - Zeba Usmani
- Department of Applied Biology, University of Science & Technology, Techno City, Killing Road, Baridua 9th Mile 793101, Meghalaya, India; (Z.U.); (M.S.)
| | - Minaxi Sharma
- Department of Applied Biology, University of Science & Technology, Techno City, Killing Road, Baridua 9th Mile 793101, Meghalaya, India; (Z.U.); (M.S.)
| | - James W. Nelson
- Department of Neurosurgery, Washington University School of Medicine, Saint Louis, MO 63110, USA; (D.D.); (J.W.N.)
| | - Vijay Kumar Thakur
- Biorefining and Advanced Materials Research Center, SRUC, Edinburgh EH9 3JG, UK;
- School of Engineering, University of Petroleum & Energy Studies (UPES), Dehradun 248007, Uttarakhand, India
| | - Graham Christie
- Department of Chemical Engineering & Biotechnology, University of Cambridge, Cambridge CB2 1TN, UK;
| | - Gustavo Molina
- Laboratory of Bioflavors and Bioactive Compounds, Department of Food Science, Faculty of Food Engineering, State University of Campinas, R. Monteiro Lobato, 80, Campinas, São Paulo 13083-862, Brazil;
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Center, SRUC, Edinburgh EH9 3JG, UK;
- Centre for Safe and Improved Food, SRUC, Edinburgh EH9 3JG, UK
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Faraji H, Soltani F, Ramezani M, Sadeghnia HR, Nedaeinia R, Moghimi Benhangi H, Mashkani B. Designing a multifunctional staphylokinase variant (SAK-2RGD-TTI) with appropriate thrombolytic activity in vitro. Biotechnol Lett 2019; 42:103-114. [PMID: 31686286 DOI: 10.1007/s10529-019-02748-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/18/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Thrombin, platelets, and plasmin are three key factors involved in hemostasis and thrombolysis. Thrombolytic therapy with clinically approved drugs is often followed by recurrent thrombosis caused by thrombin-induced platelet aggregation from the clot debris. In order to minimize these problems, new constructs were designed for the expression of recombinant staphylokinase (rSAK) and also a fusion protein composed of staphylokinase, 20 amino acids containing 2 RGD followed by tsetse thrombin Inhibitor (SAK-2RGD-TTI) in Pichia pastoris. RESULT Modeling the tertiary structure of SAK-2RGD-TTI showed that the linker containing RGD and TTI did not interfere with proper folding of SAK. In laboratory testing, the purified SAK-2RGD-TTI (420 μg/mL) dissolved an average of 45% of the blood clot. The activity of the SAK-2RGD-TTI was also confirmed in various tests including human plasminogen activation assay, fibrin clot lysis assay, well diffusion method, activated partial thromboplastin time and platelet rich clot lysis assay. CONCLUSION Our findings suggest that SAK-2RGD-TTI has improved therapeutic properties preventing reocclussion. It further confirms that it is practicable to assemble and produce a hybrid multifunctional protein that targets hemostatic process at various stages.
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Affiliation(s)
- Habibollah Faraji
- Department of Laboratory Sciences, Faculty of Para-medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Fatemeh Soltani
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Ramezani
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid Reza Sadeghnia
- Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reza Nedaeinia
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamid Moghimi Benhangi
- Department of Toxicology, Islamic Azad University, Shahreza Branch, Shahreza, Isfahan, Iran
| | - Baratali Mashkani
- Bioinformatics Research Group, Mashhad University of Medical Sciences, Mashhad, Iran.
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Nedaeinia R, Faraji H, Javanmard SH, Ferns GA, Ghayour-Mobarhan M, Goli M, Mashkani B, Nedaeinia M, Haghighi MHH, Ranjbar M. Bacterial staphylokinase as a promising third-generation drug in the treatment for vascular occlusion. Mol Biol Rep 2019; 47:819-841. [PMID: 31677034 DOI: 10.1007/s11033-019-05167-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022]
Abstract
Vascular occlusion is one of the major causes of mortality and morbidity. Blood vessel blockage can lead to thrombotic complications such as myocardial infarction, stroke, deep venous thrombosis, peripheral occlusive disease, and pulmonary embolism. Thrombolytic therapy currently aims to rectify this through the administration of recombinant tissue plasminogen activator. Research is underway to design an ideal thrombolytic drug with the lowest risk. Despite the potent clot lysis achievable using approved thrombolytic drugs such as alteplase, reteplase, streptokinase, tenecteplase, and some other fibrinolytic agents, there are some drawbacks, such as high production cost, systemic bleeding, intracranial hemorrhage, vessel re-occlusion by platelet-rich and retracted secondary clots, and non-fibrin specificity. In comparison, bacterial staphylokinase, is a new, small-size plasminogen activator, unlike bacterial streptokinase, it hinders the systemic degradation of fibrinogen and reduces the risk of severe hemorrhage. A fibrin-bound plasmin-staphylokinase complex shows high resistance to a2-antiplasmin-related inhibition. Staphylokinase has the potential to be considered as a promising thrombolytic agent with properties of cost-effective production and the least side effects.
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Affiliation(s)
- Reza Nedaeinia
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Habibollah Faraji
- Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran. .,Department of Laboratory Sciences, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
| | - Shaghayegh Haghjooye Javanmard
- Applied Physiology Research Center, Cardiovascular Research Institute, Isfahan University of Medical Science, Isfahan, Iran
| | - Gordon A Ferns
- Brighton and Sussex Medical School, Division of Medical Education, Falmer, Brighton, Sussex, BN1 9PH, UK
| | - Majid Ghayour-Mobarhan
- Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Goli
- Department of Food Science and Technology, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
| | - Baratali Mashkani
- Department of Medical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mozhdeh Nedaeinia
- Young Researchers and Elite Club, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
| | - Mohammad Hossein Hayavi Haghighi
- Department of Health Information Management, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Maryam Ranjbar
- Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran.,Deputy of Food and Drug, Isfahan University of Medical Sciences, Isfahan, Iran
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Faraji H, Ramezani M, Mashkani B, Sadeghnia HR, Benhangi HM, Hosseini Teshnizi S, Soltani F. Comparison of expression optimization of new derivative of staphylokinase (SAK-2RGD-TTI) with the rSAK. Biotechnol Prog 2019; 35:e2819. [PMID: 30972956 DOI: 10.1002/btpr.2819] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 01/07/2019] [Accepted: 03/27/2019] [Indexed: 11/06/2022]
Abstract
Staphylokinase (SAK) is a promising thrombolytic agent for the treatment of patients suffering from blood-clotting disorders. To increase the potency of SAK and to minimize vessel reocclusion, a new construct bearing SAK motif fused to tsetse thrombin inhibitor (TTI) via a 20-amino acid linker with 2 RGD (2 × arginine-glycine-aspartic acid inhibiting platelet aggregation via attachment to integrin receptors of platelet) was codon optimized and expressed comparatively in Pichia pastoris GS115 as a Mut+ strain and KM71H as a Muts strain. Fusion protein was optimized in terms of best expression condition and fibrinolytic activity and compared with the rSAK. Expression level of the designed construct reached up to 175 mg/L of the culture medium after 72-hr stimulation with 2.5% methanol and remained steady for 3-4 days. The highest expression was obtained at the range of 2-3% methanol. The SAK-2RGD-TT (relative activity >82%) was more active at 25-37 °C than rSAK (relative activity of 93%). Further, it showed relative activity >80% at pH ranges of 7-9. Western blot analysis showed two bands of nearly 27 and 24 kDa at ratio of 5 to 3, respectively. The specific fibrinolytic activity of the SAK-2RGD-TTI was measured as 8,269 U/mg, and 19,616 U/mg for the nonpurified and purified proteins, respectively. Deglycosylation by using tunicamycin in culture medium resulted in higher fibrinolytic activity of SAK-2RGD-TTI (2.2 fold). Consequently, compared to the rSAK, at the same equimolar proportion, addition of RGD and TTI fragments could increase fibrinolytic activity. Also, P. pastoris can be considered as an efficient host for overexpression of the soluble SAK-2RGD-TTI with high activity without requiring a complicated purification procedure.
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Affiliation(s)
- Habibollah Faraji
- Department of Laboratory Sciences, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Mohammad Ramezani
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Baratali Mashkani
- Department of Medical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid R Sadeghnia
- Neurocognitive Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of New Sciences and Technology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid M Benhangi
- Department of Toxicology, Islamic Azad University, Shahreza, Isfahan, Iran
| | - Saeed Hosseini Teshnizi
- Department of Biostatistics, School of Medicine, Shiraz University of Medical Science, Shiraz, Iran
| | - Fatemeh Soltani
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
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Atanassov A, Tchorbanov B. Synthetic and Natural Peptides as Antithrombotic Agents—A View on the Current Development. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.1080/13102818.2009.10817623] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Tatterton M, Wilshaw SP, Ingham E, Homer-Vanniasinkam S. The use of antithrombotic therapies in reducing synthetic small-diameter vascular graft thrombosis. Vasc Endovascular Surg 2012; 46:212-22. [PMID: 22308212 DOI: 10.1177/1538574411433299] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Thrombosis of synthetic small-diameter bypass grafts remains a major problem. The aim of this article is to review the antithrombotic strategies that have been used in an attempt to reduce graft thrombogenicity. METHODS A PubMed/MEDLINE search was performed using the search terms "vascular graft thrombosis," "small-diameter graft thrombosis," "synthetic graft thrombosis" combined with "antithrombotic," "antiplatelet," "anticoagulant," "Dacron," "PTFE," and "polyurethane." RESULTS The majority of studies on antithrombotic therapies have used either in vitro models or in vivo animal experiments. Many of the therapies used in these settings do show antithrombotic efficacy against synthetic graft materials. There is however, a distinct lack of human in vivo studies to further delineate the performance and limitations of therapies displaying good antithrombotic characteristics. CONCLUSION Very few antithrombotic therapies have translated into clinical use. More human in vivo studies are required to assess the efficacy and safety of such therapies.
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Affiliation(s)
- Mark Tatterton
- Leeds Vascular Institute, Leeds General Infirmary, Leeds, Yorkshire, UK.
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Zhang YG, Yue L, Wang YX, Tao XM, Song HY. Design of a novel plasminogen activator based on the structure of hirudin. Acta Biochim Biophys Sin (Shanghai) 2006; 38:531-6. [PMID: 16894474 DOI: 10.1111/j.1745-7270.2006.00199.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Using a phage library, seven peptide sequences with high affinity to human microplasminogen were obtained. Caseinolytic assay indicated that only the synthesized peptide P07 had slight fibrinolytic activity. To enhance its plasminogen activation ability, peptide P07 was fused into loop 32-35 of hirudin. In vitro assay demonstrated that this hirudin-like fusion protein can activate human plasminogen and retain the function of thrombin inhibition. Fusing the sequence ''SPDASRL'' into hirudin generated a plasminogen activation activity 100 times higher than peptide P07 in chromogenic and radial caseinolytic assay. This significant functional improvement might originate from a more specific active structure due to the hirudin scaffold.
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Affiliation(s)
- Yu-Gao Zhang
- The Key Laboratory of Molecular Medicine, Ministry of Education, Fudan University, Shanghai 200032, China
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Johnson C, Royal M, Moreadith R, Bedu-Addo F, Advant S, Wan M, Conn G. Monitoring manufacturing process yields, purity and stability of structural variants of PEGylated staphylokinase mutant SY161 by quantitative reverse-phase chromatography. Biomed Chromatogr 2003; 17:335-44. [PMID: 12884399 DOI: 10.1002/bmc.249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Staphylokinase variant SY161 is a recombinant mutant of the Staphylococcus aureus polypeptide staphylokinase (Sak), and is currently in human clinical trials as a thrombolytic agent. The 15 kDa single chain SY161 protein is expressed as a soluble cytoplasmic product in E. coli with a single cysteine inserted near the N-terminus. The protein as extracted from E. coli is a mixture of both monomeric and intermolecularly disulfide crosslinked species. To improve protein purification yields SY161 is sulfitolyzed during the early stages of production, preventing disulfide formation. The protein is later modified during manufacturing to incorporate a single 5 kDa polyethylene glycol group on the single sulfhydryl sidechain. We have developed and qualified a reverse-phase chromatographic method to quantitate SY161 during product manufacturing. We discuss the use of the assay during manufacturing development to monitor fermentation yields, the SY161 PEGylation reaction, and as an in-process manufacturing control assay. The assay has been applied as a product purity and identity release assay and is suitable for use in assessing product structural integrity during stability testing. The assay has a linear range of quantitation for SY161 from at least 0.15 to 16 micro g, and is-in addition capable of detecting and quantitating protein de-PEGylation events and host cell-derived protein contaminants.
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Affiliation(s)
- Catharine Johnson
- Pharmaceutical Sciences, Diosynth-RTP, 3000 Weston Parkway, Cary, NC 27513, USA
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Icke C, Schlott B, Ohlenschläger O, Hartmann M, Gührs KH, Glusa E. Fusion proteins with anticoagulant and fibrinolytic properties: functional studies and structural considerations. Mol Pharmacol 2002; 62:203-9. [PMID: 12130670 DOI: 10.1124/mol.62.2.203] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In an effort to combine the benefits of fibrinolytics, such as staphylokinase, with those of thrombin inhibitors for the prevention of vessel reocclusion after vascular injury, we have produced several chimeric proteins with plasminogen-activating and thrombin-inhibiting properties. Fusion proteins were constructed consisting of the modules staphylokinase (Sak), the factor Xa cleavage site, and various dipetalin (Dip) domains (H(6)-Sak-Dip-I+II, H(6)-Sak-Dip-I, and H(6)-Sak-Dip-II). Sak stimulates fibrinolysis via activation of plasminogen, whereas dipetalin is a two-domain, Kazal-type inhibitor of thrombin. NMR spectroscopy of the fusion proteins revealed that the molecular structures of the modules are retained in the fusion protein and that no significant interactions occur between the modules in terms of their functionally relevant regions. In enzymatic thrombin inhibition tests and blood coagulation assays (thrombin, prothrombin, and activated partial thromboplastin times), no significant differences in anticoagulant capacity were observed between the fusion protein H(6)-Sak-Dip-I+II and isolated Dip-I+II, even at nanomolar concentrations. Similar results (i.e., the inhibition of thrombin-induced platelet aggregation and the inhibition of thrombin-induced vascular relaxation) were obtained when the cellular thrombin effects were studied. The fusion protein containing Dip-I has less but still significant thrombin inhibitory effects compared with those of H(6)-Sak-Dip-I+II. In contrast, the H(6)-Sak-Dip-II protein failed to inhibit thrombin in each of the assays used. The plasminogen-activating and fibrinolytic activities of the fusion proteins are similar to those of wild-type Sak. The individual dipetalin domains do not activate plasminogen. In conclusion, the fusion protein H(6)-Sak-Dip-I+II is a bifunctional molecule able to activate fibrinolysis via plasminogen activation and inhibit blood coagulation via direct inhibition of thrombin.
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Affiliation(s)
- Christian Icke
- Friedrich-Schiller-Universität Jena, Zentrum für Vaskuläre Biologie und Medizin, Erfurt, Germany
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Swenson S, Bush LR, Markland FS. Chimeric derivative of fibrolase, a fibrinolytic enzyme from southern copperhead venom, possesses inhibitory activity on platelet aggregation. Arch Biochem Biophys 2001; 384:227-37. [PMID: 11368309 DOI: 10.1006/abbi.2000.2129] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fibrolase, a metalloproteinase isolated from the venom of Agkistrodon contortrix contortrix (southern copperhead snake), is a direct acting fibrinolytic enzyme that has been used to digest occlusive blood clots in animal models. The snake venom enzyme directly degrades fibrin associated with platelet rich blood clots and does not rely on plasminogen activation. Rethrombosis is a serious complication that is experienced in a significant percentage of patients treated with thrombolytic agents to remove occlusive vascular thrombi. The involvement of platelets in the initiation of rethrombosis is well known. Arg-Gly-Asp-(RGD)-containing agents have been shown to inhibit rethrombosis following thrombus dissolution by plasminogen activators. In an effort to create a more effective fibrinolytic enzyme and to target the enzyme to platelet-rich thrombi, thereby decreasing the potential for rethrombosis, a chimeric derivative of fibrolase has been produced. This report describes the construction and biochemical characterization of the chimeric enzyme and an evaluation of its in vitro activities. The chimera was formed by covalently incorporating an RGD-like peptide into fibrolase. The site of peptide attachment was determined to be a single lysine residue remote from the enzymes active site. Covalent modification of fibrolase with the RGD-like peptide did not inhibit either fibrinolytic activity of the enzyme nor platelet aggregation inhibitory activity of the peptide. The chimera not only retained the same level of enzymatic activity as native fibrolase, but also acquired the ability to inhibit platelet aggregation by binding to the fibrinogen receptor (integrin alphaIIbbeta3) on platelets.
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Affiliation(s)
- S Swenson
- Department of Biochemistry and Molecular Biology and Norris Comprehensive Cancer Center, University of Southern California, Keck School of Medicine, Los Angeles 90033, USA
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van Wyk V, Leblond L, Winocour PD, Devine DV, Gyongyossy-Issa MI. Incorporation of an Asp-Ser sequence to form an RGDS-like motif in hirutonin: the effect on in vitro platelet function. Thromb Res 2000; 99:343-52. [PMID: 10963785 DOI: 10.1016/s0049-3848(00)00257-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We investigated the effect on in vitro platelet function of hirutonin, a modified hirutonin with an RGD-like motif, a pseudo-RGDS peptide and a linear RGDS peptide. Inhibition of expression of surface fibrinogen on ADP-activated platelets with 40 microM of the peptide was as follows: hirutonin 10+/-3%, modified chimeric peptide 26+/-5%, pseudo-RGDS 66+/-11% and linear RGDS 93+/-13%. Both hirutonin and the chimeric peptide significantly inhibited ADP-induced platelet activation as detected by CD62 expression. Unlike the RGDS and pseudo-RGDS controls, neither the chimeric peptide nor the parent hirutonin inhibited ADP-induced platelet aggregation even at 140 microM. The chimeric hirutonin peptide reduced ATP release from ADP-stimulated platelets by 40+/-4%. This inhibition was stronger than that caused by hirutonin (23+/-13%), but less than the RGDS (90+/-2%) and pseudo RGDS-peptides (59+/-11%). Primary platelet haemostasis was slightly but not significantly affected by the peptide at 40 and 80 microM. However, shear-induced platelet adhesion to vWF and especially subsequent aggregate formation was interrupted after the addition of the chimeric peptide. Similar results were obtained with hirutonin. This inhibition was not as marked as with the RGDS- and pseudo-RGDS peptides. Both the parent hirutonin and the chimeric peptide caused prolongation of the clinical coagulation assays aPTT and TT. In conclusion, the chimeric hirutonin peptide with introduction of the RGD motif retained its anticoagulant effect but had little formal disintegrin activity. Instead, it appeared to have novel anti-platelet effects that may be of therapeutic use.
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Affiliation(s)
- V van Wyk
- Department of Haematology and Cell Biology, University of the Orange Free State, Bloemfontein, South Africa.
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van Zyl WB, Pretorius GH, Lamprecht S, Roodt JP, Kotzé HF. PLATSAK, a potent antithrombotic and fibrinolytic protein, inhibits arterial and venous thrombosis in a baboon model. Thromb Res 2000; 98:435-43. [PMID: 10828483 DOI: 10.1016/s0049-3848(00)00204-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Antiplatelet-antithrombin-staphylokinase (PLATSAK) is a chimeric protein that was recombinantly produced in Escherichia coli cells. The protein was designed to target haemostasis at three different levels. It consists of staphylokinase for activation of fibrinolyis, the Arg-Gly-Asp sequence for the prevention of platelet aggregation, and an antithrombotic peptide for the inhibition of thrombin. The in vivo activity of PLATSAK was evaluated by assessing its effect on platelet deposition in a baboon model of arterial and venous thrombosis. Dacron vascular graft segments and expansion chambers, inserted as extensions into permanent femoral arteriovenous shunts, were used to simulate arterial and venous thrombosis, respectively. PLATSAK (3.68 mg/kg) was administered as a bolus 10 minutes before placement of the thrombogenic devices. Platelet deposition onto the graft surface and in the expansion chamber was imaged in real time with a scintillation camera as the deposition of 111In-labeled platelets. After 2 hours, platelet deposition in the graft segments and expansion chambers was inhibited by 50% and 85%, respectively, when compared to control studies. The activated partial thromboplastin time was lengthened to greater than 120 seconds. Interestingly, the level of fibrinogen degradation products in plasma did not increase after administration of PLATSAK. These results demonstrate that PLATSAK effectively inhibited platelet deposition in both arterial- and venous-type thrombosis in an animal model.
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Affiliation(s)
- W B van Zyl
- Department of Haematology and Cell Biology, University of the Orange Free State, Bloemfontein, South Africa
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