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Yang N, Hao J, Zhang D. Antithrombin III and D-dimer levels as indicators of disease severity in patients with hyperlipidaemic or biliary acute pancreatitis. J Int Med Res 2017; 45:147-158. [PMID: 28222624 PMCID: PMC5536593 DOI: 10.1177/0300060516677929] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Objective To assess changes in anticoagulation and fibrinolytic systems between biliary and hyperlipidaemic acute pancreatitis (AP). Methods Patients with biliary or hyperlipidaemic AP were enrolled. Demographic and clinical data were collected, and antithrombin III (ATIII), protein C, protein S, and D-dimer levels were investigated. Results A total of 45 patients with biliary AP and 50 patients with hyperlipidaemic AP were included (68 with mild AP and 27 with moderately-severe AP). ATIII and protein C levels in the mild AP group were significantly higher, but prothrombin time and D-dimer were significantly lower, versus the moderately-severe AP group. ATIII and D-dimer were found to be risk factors for moderately-severe AP. ATIII could predict AP severity, particularly in patients with biliary AP. D-dimer was a sensitive and specific predictor for disease severity in patients with AP, particularly in patients with hyperlipidaemic AP. Conclusion ATIII and protein C levels decreased as severity of AP increased, particularly in cases of biliary AP. D-dimer levels increased with severity of AP, particularly in hyperlipidaemic AP. ATIII and D-dimer may be useful biomarkers for assessing AP severity in patients with biliary and hyperlipidaemic AP, respectively.
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Affiliation(s)
- Ning Yang
- 1 Department of Endocrinology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Jianyu Hao
- 2 Department of Gastroenterology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Donglei Zhang
- 2 Department of Gastroenterology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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An efficient anticoagulant candidate: Characterization, synthesis and in vivo study of a fondaparinux analogue Rrt1.17. Eur J Med Chem 2017; 126:1039-1055. [DOI: 10.1016/j.ejmech.2016.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/26/2016] [Accepted: 12/02/2016] [Indexed: 11/20/2022]
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Radulović ŽM, Mulenga A. Heparan sulfate/heparin glycosaminoglycan binding alters inhibitory profile and enhances anticoagulant function of conserved Amblyomma americanum tick saliva serpin 19. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 80:1-10. [PMID: 27845251 PMCID: PMC5214524 DOI: 10.1016/j.ibmb.2016.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 10/25/2016] [Accepted: 11/11/2016] [Indexed: 06/06/2023]
Abstract
Some serine protease inhibitor (serpin) regulators of essential life pathways bind glycosaminoglycans (GAGs) to enhance inhibitory functions and achieve physiologically relevant rates. This study demonstrates that highly conserved Amblyomma americanum tick saliva serpin 19 (AAS19), a broad-spectrum inhibitor of hemostasis and inflammation system proteases and anticoagulant, can bind heparan sulfate/heparin (HS)GAGs and that this interaction alters its function. Substrate hydrolysis and unpaired t-test analyses revealed that HSGAG binding caused rAAS19 inhibitory activity to: (i) significantly increase against blood clotting factors (f) IIa (thrombin) and fIXa, (ii) significantly reduce against fXa and fXIIa and (iii) moderate to no effect against trypsin, kallikrein, papain, and plasmin. Stoichiometry of inhibition (SI) analyses show that HSGAG binding improved the rAAS19 inhibitory efficiency against thrombin 2.7-4.3 fold as revealed by SI change from 13.19 in absence of HSGAGs to 4.83-3.04 in their presence. Our data show that HSGAG binding dramatically enhanced rAAS19 anticoagulant function. In the recalcification time assay, rAAS19 pre-incubated with HSGAGs prior to the assay, delayed plasma clotting by an additional 176-457 s above HSGAGs or rAAS19 alone. Our data suggest that formation of the HSGAGs and rAAS19 complex is important for the observed enhanced anticoagulant effect. Delay of plasma clotting was higher when HSGAGs and rAAS19 were co-incubated to allow complex formation prior to blood clotting assay as opposed to no co-incubation. We have discussed our finding with reference to tick feeding physiology and utility of the rAAS19 in blood clotting disorder therapy.
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Affiliation(s)
- Željko M Radulović
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 422 Raymond Stotzer, TAMU 4467, College Station, TX 77843, USA
| | - Albert Mulenga
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 422 Raymond Stotzer, TAMU 4467, College Station, TX 77843, USA.
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Ulbricht D, Oertwig K, Arnsburg K, Saalbach A, Pippel J, Sträter N, Heiker JT. Basic Residues of β-Sheet A Contribute to Heparin Binding and Activation of Vaspin (Serpin A12). J Biol Chem 2016; 292:994-1004. [PMID: 27941022 DOI: 10.1074/jbc.m116.748020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/14/2016] [Indexed: 01/08/2023] Open
Abstract
Many members of the serine protease inhibitor (serpin) family are activated by glycosaminoglycans (GAGs). Visceral adipose tissue-derived serpin (vaspin), serpin A12 of the serpin family, and its target protease kallikrein 7 (KLK7) are heparin-binding proteins, and inhibition of KLK7 by vaspin is accelerated by heparin. However, the nature of GAG binding to vaspin is not known. Here, we measured vaspin binding of various glycosaminoglycans and low molecular weight heparins by microscale thermophoresis and analyzed acceleration of protease inhibition by these molecules. In addition, basic residues contributing to heparin binding and heparin activation were identified by a selective labeling approach. Together, these data show that vaspin binds heparin with high affinity (KD = 21 ± 2 nm) and that binding takes place at a basic patch on top of β-sheet A and is different from other heparin-binding serpins. Mutation of basic residues decreased heparin binding and activation of vaspin. Similarly, reactive center loop insertion into sheet A decreased heparin binding because it disturbs the basic cluster. Finally, using vaspin-overexpressing keratinocyte cells, we show that a significant part of secreted vaspin is bound in the extracellular matrix on the cell surface. Together, basic residues of central β-sheet A contribute to heparin binding and activation of vaspin. Thus, binding to GAGs in the extracellular matrix can direct and regulate vaspin interaction with target proteases or other proteins and may play an important role in the various beneficial functions of vaspin in different tissues.
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Affiliation(s)
- David Ulbricht
- From the Institute of Biochemistry, Faculty of Biosciences, Pharmacy, and Psychology
| | - Kathrin Oertwig
- From the Institute of Biochemistry, Faculty of Biosciences, Pharmacy, and Psychology
| | - Kristin Arnsburg
- From the Institute of Biochemistry, Faculty of Biosciences, Pharmacy, and Psychology
| | - Anja Saalbach
- the Department of Dermatology, Venerology, and Allergology, and
| | - Jan Pippel
- the Center for Biotechnology and Biomedicine, Institute of Bioanalytical Chemistry, University of Leipzig, 04103 Leipzig, Germany
| | - Norbert Sträter
- the Center for Biotechnology and Biomedicine, Institute of Bioanalytical Chemistry, University of Leipzig, 04103 Leipzig, Germany
| | - John T Heiker
- From the Institute of Biochemistry, Faculty of Biosciences, Pharmacy, and Psychology,
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Abstract
Heparin was discovered around 1922 by Howell (Baltimore) and was further developed by the teams of Best (Toronto) and Jorpes (Stockholm). Kakkar (London) propagated its routine use for the prevention of postoperative thrombosis from 1971 onwards. The discovery of low molecular weight heparins (1976, Johnson, London) and their development in the subsequent years led to the present arsenal of clinically useful drugs. In 1976, three teams independently found that a specific structure in heparin binds tightly to antithrombin. This enabled the teams of Lindahl (Stockholm) and Casu (Milan) to determine the pentasaccharide structure responsible for this binding and Petitou, from the Choay team (Paris), to synthesize it (1983). It was found (Olson and others) that heparin facilitates the interaction between antithrombin and a clotting enzyme by allosteric changes in the antithrombin (important for factor Xa) and by facilitating the approach of the enzyme to antithrombin via its "sliding" along the heparin molecule (important for thrombin). Antithrombin action therefore requires a minimum length of seven sugar units next to the pentasaccharide whereas anti-factor Xa action does not. The effect of heparin is almost entirely due to anti-thrombin action (B≐guin), so anti-factor Xa activity does not reflect the concentration of anticoagulant heparin. The anticoagulant effect is poorly reflected by the activated partial thromboplastin time. Because present clinical use is based on the latter tests, it is not generally known that the individual response to heparin shows an extremely wide variation. Individualization of heparin dosage is likely to improve clinical results.
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Affiliation(s)
- H C Hemker
- Synapse BV and Cardiovascular Research Institute, Maastricht, the Netherlands
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Antithrombin Concentrate Use in Pediatric Extracorporeal Membrane Oxygenation: A Multicenter Cohort Study. Pediatr Crit Care Med 2016; 17:1170-1178. [PMID: 27662567 DOI: 10.1097/pcc.0000000000000955] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To describe antithrombin concentrate use and to compare thrombotic and hemorrhagic outcomes throughout the hospital stay in pediatric subjects who received extracorporeal membrane oxygenation in a Pediatric Health Information System-participating children's hospital. DESIGN Retrospective, multi-center, cohort study. SETTING Forty-three free-standing children's hospitals participating in Pediatric Health Information System. SUBJECTS Children older than or equal to 18 years of age who underwent extracorporeal membrane oxygenation between 2003 and 2012. INTERVENTIONS Subjects were classified as receiving antithrombin if they received at least one dose of antithrombin while on extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS International Classification of Diseases, Ninth Revision, Clinical Modification codes codes were used to identify hemorrhagic and thrombotic complications during their hospitalization. Pediatric Health Information System data were analyzed to determine hospital-length of stay and in-hospital mortality. A total of 1,931 of 8,601 eligible subjects (21.5%) received at least one dose of antithrombin during their extracorporeal membrane oxygenation course. Antithrombin use during extracorporeal membrane oxygenation increased from 2.4% to 51.9% (p < 0.001) over the 10-year study period. Subjects who received antithrombin while on extracorporeal membrane oxygenation were younger (p = 0.02), had more chronic conditions (p < 0.001), and longer hospital stays (p < 0.001). On multivariate analysis, antithrombin use was associated with thrombotic events (odds ratio, 1.55; 95% CI, 1.36-1.77; p < 0.001), hemorrhagic events (odds ratio, 1.27; 95% CI, 1.14-1.42; p < 0.001), and longer hospital length of stays (slope coefficient, 1.05 d; 95% CI, 1.04-1.06; p < 0.001). No difference was observed in mortality (odds ratio, 0.99; 95% CI, 0.89-1.11; p = 0.90). CONCLUSIONS In this multicenter retrospective cohort study, subjects who received antithrombin during extracorporeal membrane oxygenation had a higher number of thrombotic and hemorrhagic events throughout the hospitalization and longer length of stays without an associated difference in mortality. While limitations exist with this analysis and results should be interpreted with caution, the fact remains that over half of pediatric patients on extracorporeal membrane oxygenation are currently receiving antithrombin without clear benefit, with extra cost, and potential harms, there needs to be strong consideration for a clinical trial.
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Liu T, Hu Y, Tan J, Liu S, Chen J, Guo X, Pan C, Li X. Surface biomimetic modification with laminin-loaded heparin/poly-l-lysine nanoparticles for improving the biocompatibility. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 71:929-936. [PMID: 27987790 DOI: 10.1016/j.msec.2016.11.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/13/2016] [Accepted: 11/02/2016] [Indexed: 11/28/2022]
Abstract
Late thrombus and restenosis caused by delayed endothelialization and insufficient biocompatibility of polymer coating continue to be the greatest limitations of drug-eluting stents. In this study, based on the specific structure of vascular basement membrane, a novel biomimetic nano-coating was constructed by incorporating laminin into electrostatic-assembled heparin/poly-l-lysine nanoparticles. Alteration of heparin and poly-l-lysine concentration ratio in a certain range has no significantly influence nanoparticle size, uniformity and stability, but may affect the chemical property and subsequently the binding efficiency to dopamine-coated titanium surface. By use of this feature, four different nanoparticles were synthesized and immobilized on titanium surface for creating gradient nanoparticle binding density. According to in vitro biocompatibility evaluation, the nanoparticle modified surfaces were found to effectively block coagulation pathway and reduce thrombosis formation. Moreover, NP10L and NP15L modified surface with relatively low heparin exposing density (4.9 to 7.1μg/cm2) showed beneficial effect in selective promoting EPCs and ECs proliferation, as well as stimulating cell migration and NO synthesis.
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Affiliation(s)
- Tao Liu
- Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an, China.
| | - Youdong Hu
- Department of Geriatrics, The Affiliated Huai'an Hospital of Xuzhou Medical College, Huai'an, China
| | - Jianying Tan
- Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Shihui Liu
- Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an, China
| | - Junying Chen
- Key Lab. of Advanced Technology for Materials of Chinese Education Ministry, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Xin Guo
- Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an, China
| | - Changjiang Pan
- Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huai'an, China
| | - Xia Li
- Department of Geriatrics, The Affiliated Huai'an Hospital of Xuzhou Medical College, Huai'an, China.
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Dong K, Song Y, Li X, Ding J, Gao Z, Lu D, Zhu Y. Pentasaccharides for the prevention of venous thromboembolism. Cochrane Database Syst Rev 2016; 10:CD005134. [PMID: 27797404 PMCID: PMC6463830 DOI: 10.1002/14651858.cd005134.pub3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Venous thromboembolism (VTE) is a common condition with potentially serious and life-threatening consequences. The standard method of thromboprophylaxis uses an anticoagulant such as low molecular weight heparin (LMWH) or warfarin. In recent years, another type of anticoagulant, pentasaccharide, an indirect factor Xa inhibitor, has shown good anticoagulative effect in clinical trials. Three types of pentasaccharides are available: short-acting fondaparinux, long-acting idraparinux and idrabiotaparinux. Pentasaccharides cause little heparin-induced thrombocytopenia and are better tolerated than unfractionated heparin, LMWH and warfarin. However, no consensus has been reached on whether pentasaccharides are superior or inferior to other anticoagulative methods. OBJECTIVES To assess effects of pentasaccharides versus other methods of thromboembolic prevention (thromboprophylaxis) in people who require anticoagulant treatment to prevent venous thromboembolism. SEARCH METHODS The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched March 2016) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2). The CIS searched trial databases for details of ongoing and unpublished studies. Review authors searched LILACS (Latin American and Caribbean Health Sciences) and the reference lists of relevant studies and reviews identified by electronic searches. SELECTION CRITERIA We included randomised controlled trials on any type of pentasaccharide versus other anticoagulation methods (pharmaceutical or mechanical) for VTE prevention. DATA COLLECTION AND ANALYSIS Two review authors independently selected trials, assessed methodological quality and extracted data in predesigned tables. MAIN RESULTS We included in this review 25 studies with a total of 21,004 participants. All investigated fondaparinux for VTE prevention; none investigated idraparinux or idrabiotaparinux. Studies included participants undergoing abdominal surgery, thoracic surgery, bariatric surgery or coronary bypass surgery; acutely ill hospitalised medical patients; people requiring rigid or semirigid immobilisation; and those with superficial venous thrombosis. Most studies focused on orthopaedic patients. We lowered the quality of the evidence because of heterogeneity between studies and a small number of events causing imprecision.When comparing fondaparinux with placebo, we found less total VTE (risk ratio (RR) 0.24, 95% confidence interval (CI) 0.15 to 0.38; 5717 participants; 8 studies; I2 = 64%; P < 0.00001), less symptomatic VTE (RR 0.15, 95% CI 0.06 to 0.36; 6503 participants; 8 studies; I2 = 0%; P < 0.0001), less total DVT (RR 0.25, 95% CI 0.15 to 0.40; 5715 participants; 8 studies; I2 = 67%; P < 0.00001), less proximal DVT (RR 0.12, 95% CI 0.04 to 0.39; 2746 participants; 7 studies; I2 = 64%; P = 0.0004) and less total pulmonary embolism (PE) (RR 0.16, 95% CI 0.04 to 0.62; 6412 participants; 8 studies; I2 = 0%; P = 0.008) in the fondaparinux group. The quality of the evidence was moderate for total VTE, total DVT and proximal DVT, and high for symptomatic VTE and total PE.When fondaparinux was compared with LMWH, analyses indicated that fondaparinux reduced total VTE and DVT (RR 0.55, 95% CI 0.42 to 0.73; 9339 participants; 11 studies; I2 = 64%; P < 0.0001; and RR 0.54, 95% CI 0.40 to 0.71; 9356 participants; 10 studies; I2 = 67%; P < 0.0001, respectively), and showed a trend toward reduced proximal DVT (RR 0.58, 95% CI 0.33 to 1.02; 8361 participants; 9 studies; I2 = 53%; P = 0.06). Symptomatic VTE (RR 1.03, 95% CI 0.65 to 1.63; 12240 participants; 9 studies; I2 = 35%; P = 0.90) and total PE (RR 1.24, 95% CI 0.65 to 2.34; 12350 participants; 10 studies; I2 = 0%; P = 0.51) indicated no difference between fondaparinux and LMWH. The quality of the evidence was moderate for total VTE, symptomatic VTE, total DVT and total PE, and low for proximal DVT.We showed that fondaparinux increased major bleeding compared with both placebo and LWMH (RR 2.56, 95% CI 1.48 to 4.44; 6659 participants; 8 studies; I2 = 0%; P = 0.0008; moderate-quality evidence; and RR 1.38, 95% CI 1.09 to 1.75; 12,501 participants; 11 studies; I2 = 24%; P = 0.008; high-quality evidence, respectively). All-cause mortality was not different between fondaparinux and placebo or LMWH (RR 0.76, 95% CI 0.48 to 1.22; 6674 participants; 8 studies; I2 = 14%; P = 0.26; moderate-quality evidence; and RR 0.88, 95% CI 0.63 to 1.22; 12,400 participants; 11 studies; I2 = 0%; P = 0.44; moderate-quality evidence, respectively).One study compared fondaparinux with variable and fixed (1 mg per day) doses of warfarin after elective hip or knee replacement surgery and showed no difference in primary and secondary outcomes between fondaparinux and both variable and fixed doses of warfarin. The quality of the evidence was very low. One small study compared fondaparinux with edoxaban in patients with severe renal impairment undergoing lower-limb orthopaedic surgery and reported no thromboembolic events, major bleeding events or deaths in either group. The quality of the evidence was very low. One small study compared fondaparinux with mechanical thromboprophylaxis. Results showed no difference in total VTE and total DVT between fondaparinux and mechanical thromboprophylaxis. This study reported no cases pertaining to the other outcomes of this review. The quality of the evidence was low.There were insufficient studies to permit meaningful conclusions for subgroups of clinical conditions other than orthopaedic surgery. AUTHORS' CONCLUSIONS Moderate to high quality evidence shows that fondaparinux is effective for short-term prevention of VTE when compared with placebo. It can reduce total VTE, DVT, total PE and symptomatic VTE, and does not demonstrate a reduction in deaths compared with placebo. Low to moderate quality evidence shows that fondaparinux is more effective for short-term VTE prevention when compared with LMWH. It can reduce total VTE and total DVT and does not demonstrate a reduction in deaths when compared with LMWH. However, at the same time, moderate to high quality evidence shows that fondaparinux increases major bleeding when compared with placebo and LMWH. Therefore, when fondaparinux is chosen for the prevention of VTE, attention should be paid to the person's bleeding and thrombosis risks. Most data were derived from patients undergoing orthopaedic surgery. Therefore, the conclusion predominantly pertains to these patients. Data on fondaparinux for other clinical conditions are sparse.
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Affiliation(s)
- Kezhou Dong
- The 2nd Jiangsu Province Hospital of TCM, Nanjing University of Chinese MedicineDepartment of RespirationNo.155, Hanzhong RoadNanjingChina
| | - Yanzhi Song
- Shanghai Daopei Hospital, Fudan UniversityShanghaiChina
| | - Xiaodong Li
- BenQ Medical Center, Nanjing Medical UniversityDepartment of RadiotherapyNanjingJiangsu ProvinceChina210019
| | - Jie Ding
- National Institute on Aging, NIHLaboratory of Epidemiology and Population Science7201 Wisconsin Ave, Suite 3C‐309BethesdaMarylandUSAMD 20814
| | - Zhiyong Gao
- Shanghai Daopei Hospital, Fudan UniversityShanghaiChina
| | - Daopei Lu
- Shanghai Daopei Hospital, Fudan UniversityShanghaiChina
| | - Yimin Zhu
- The 2nd Jiangsu Province Hospital of TCM, Nanjing University of Chinese MedicineDepartment of RespirationNo.155, Hanzhong RoadNanjingChina
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Motamedi-Shad N, Jagger AM, Liedtke M, Faull SV, Nanda AS, Salvadori E, Wort JL, Kay CW, Heyer-Chauhan N, Miranda E, Perez J, Ordóñez A, Haq I, Irving JA, Lomas DA. An antibody that prevents serpin polymerisation acts by inducing a novel allosteric behaviour. Biochem J 2016; 473:3269-90. [PMID: 27407165 PMCID: PMC5264506 DOI: 10.1042/bcj20160159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 11/30/2022]
Abstract
Serpins are important regulators of proteolytic pathways with an antiprotease activity that involves a conformational transition from a metastable to a hyperstable state. Certain mutations permit the transition to occur in the absence of a protease; when associated with an intermolecular interaction, this yields linear polymers of hyperstable serpin molecules, which accumulate at the site of synthesis. This is the basis of many pathologies termed the serpinopathies. We have previously identified a monoclonal antibody (mAb4B12) that, in single-chain form, blocks α1-antitrypsin (α1-AT) polymerisation in cells. Here, we describe the structural basis for this activity. The mAb4B12 epitope was found to encompass residues Glu32, Glu39 and His43 on helix A and Leu306 on helix I. This is not a region typically associated with the serpin mechanism of conformational change, and correspondingly the epitope was present in all tested structural forms of the protein. Antibody binding rendered β-sheet A - on the opposite face of the molecule - more liable to adopt an 'open' state, mediated by changes distal to the breach region and proximal to helix F. The allosteric propagation of induced changes through the molecule was evidenced by an increased rate of peptide incorporation and destabilisation of a preformed serpin-enzyme complex following mAb4B12 binding. These data suggest that prematurely shifting the β-sheet A equilibrium towards the 'open' state out of sequence with other changes suppresses polymer formation. This work identifies a region potentially exploitable for a rational design of ligands that is able to dynamically influence α1-AT polymerisation.
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Affiliation(s)
- Neda Motamedi-Shad
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Alistair M. Jagger
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Maximilian Liedtke
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
| | - Sarah V. Faull
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, U.K
| | - Arjun Scott Nanda
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Enrico Salvadori
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, U.K
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Joshua L. Wort
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Christopher W.M. Kay
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, U.K
| | - Narinder Heyer-Chauhan
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of Rome, Rome 00185, Italy
| | - Juan Perez
- Departamento de Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Campus Teatinos, Universidad de Malaga, Malaga 29071, Spain
| | - Adriana Ordóñez
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, U.K
| | - Imran Haq
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - James A. Irving
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - David A. Lomas
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
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Enkhbaatar P, Pruitt BA, Suman O, Mlcak R, Wolf SE, Sakurai H, Herndon DN. Pathophysiology, research challenges, and clinical management of smoke inhalation injury. Lancet 2016; 388:1437-1446. [PMID: 27707500 PMCID: PMC5241273 DOI: 10.1016/s0140-6736(16)31458-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/11/2016] [Accepted: 08/16/2016] [Indexed: 01/02/2023]
Abstract
Smoke inhalation injury is a serious medical problem that increases morbidity and mortality after severe burns. However, relatively little attention has been paid to this devastating condition, and the bulk of research is limited to preclinical basic science studies. Moreover, no worldwide consensus criteria exist for its diagnosis, severity grading, and prognosis. Therapeutic approaches are highly variable depending on the country and burn centre or hospital. In this Series paper, we discuss understanding of the pathophysiology of smoke inhalation injury, the best evidence-based treatments, and challenges and future directions in diagnostics and management.
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Affiliation(s)
- Perenlei Enkhbaatar
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX, USA.
| | - Basil A Pruitt
- Department of Surgery, Division of Trauma, University of Texas Health Science Center, San Antonio, TX, USA
| | - Oscar Suman
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA; Shriners Hospitals for Children, Galveston, TX, USA
| | - Ronald Mlcak
- Shriners Hospitals for Children, Galveston, TX, USA; Department of Respiratory Care, School of Health Professions, University of Texas Medical Branch, Galveston, TX, USA
| | - Steven E Wolf
- Department of Surgery, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Hiroyuki Sakurai
- Department of Plastic and Reconstructive Surgery, Tokyo Women's Medical University, Tokyo, Japan
| | - David N Herndon
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA; Shriners Hospitals for Children, Galveston, TX, USA
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61
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In vitro and in vivo effects of hemodilution on kaolin-based activated clotting time predicted heparin requirement using a heparin dose–response technique. J Anesth 2016; 30:923-928. [PMID: 27502398 DOI: 10.1007/s00540-016-2227-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
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62
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A rapid pro-hemostatic approach to overcome direct oral anticoagulants. Nat Med 2016; 22:924-32. [PMID: 27455511 DOI: 10.1038/nm.4149] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/16/2016] [Indexed: 02/07/2023]
Abstract
Direct inhibitors of coagulation factor Xa (FXa) or thrombin are promising oral anticoagulants that are becoming widely adopted. The ability to reverse their anticoagulant effects is important when serious bleeding occurs or urgent medical procedures are needed. Here, using experimental mouse models of hemostasis, we show that a variant coagulation factor, FXa(I16L), rapidly restores hemostasis in the presence of the anticoagulant effects of these inhibitors. The ability of FXa(I16L) to reverse the anticoagulant effects of FXa inhibitor depends, at least in part, on the ability of the active site inhibitor to hinder antithrombin-dependent FXa inactivation, paradoxically allowing uninhibited FXa to persist in plasma. Because of its inherent catalytic activity, FXa(I16L) is more potent (by >50-fold) in the hemostasis models tested than a noncatalytic antidote that is currently in clinical development. FXa(I16L) also reduces the anticoagulant-associated bleeding in vivo that is induced by the thrombin inhibitor dabigatran. FXa(I16L) may be able to fill an important unmet clinical need for a rapid, pro-hemostatic agent to reverse the effects of several new anticoagulants.
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63
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Sarkar A, Yu W, Desai UR, MacKerell AD, Mosier PD. Estimating glycosaminoglycan-protein interaction affinity: water dominates the specific antithrombin-heparin interaction. Glycobiology 2016; 26:1041-1047. [PMID: 27496757 DOI: 10.1093/glycob/cww073] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/01/2016] [Accepted: 07/12/2016] [Indexed: 11/13/2022] Open
Abstract
Glycosaminoglycan (GAG)-protein interactions modulate many important biological processes. Structure-function studies on GAGs may reveal probes and drugs, but their structural complexity and highly acidic nature confound such work. Productivity will increase if we are able to identify tight-binding oligosaccharides in silico. An extension of the CHARMM force field is presented to enable modeling of polysaccharides containing sulfamate functionality, and is used to develop a reliable alchemical free-energy perturbation protocol that estimates changes in affinity for the prototypical heparin-antithrombin system to within 2.3 kcal/mol using modest simulation times. Inclusion of water is crucial during simulation as solvation energy was equal in magnitude to the sum of all other thermodynamic factors. In summary, we have identified and optimized a reliable method for estimation of GAG-protein binding affinity, and shown that solvation is a crucial component in GAG-protein interactions.
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Affiliation(s)
- Aurijit Sarkar
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, NC 27268, USA .,Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, PO Box 980133, Richmond, VA 23298, USA
| | - Wenbo Yu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA
| | - Umesh R Desai
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, PO Box 980133, Richmond, VA 23298, USA
| | - Alexander D MacKerell
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA
| | - Philip D Mosier
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, PO Box 980133, Richmond, VA 23298, USA
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64
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Chandarajoti K, Liu J, Pawlinski R. The design and synthesis of new synthetic low-molecular-weight heparins. J Thromb Haemost 2016; 14:1135-45. [PMID: 26990516 PMCID: PMC4907857 DOI: 10.1111/jth.13312] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 03/01/2016] [Indexed: 12/13/2022]
Abstract
Low-molecular-weight heparin (LMWH) has remained the most favorable form of heparin in clinics since the 1990s owing to its predictable pharmacokinetic properties. However, LMWH is mainly eliminated through the kidney, which limits its use in renal-impaired patients. In addition, the anticoagulant activity of LMWH is only partially neutralized by protamine. LMWH is obtained from a full-length, highly sulfated polysaccharide harvested from porcine mucosal tissue. The depolymerization involved in LMWH production generates a broad distribution of LMWH fragments (6-22 sugar residues). This, combined with the various methods used to produce commercial LMWHs, results in variable pharmacological and pharmacokinetic properties. An alternative chemoenzymatic approach offers a method for the synthesis of LMWH that has the potential to overcome the limitations of current LMWHs. This review summarizes the application of a chemoenzymatic approach to generate LMWH and the rationale for development of a synthetic LMWH.
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Affiliation(s)
- K Chandarajoti
- Division of Hematology and Oncology, McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - J Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - R Pawlinski
- Division of Hematology and Oncology, McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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65
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The M358R variant of α(1)-proteinase inhibitor inhibits coagulation factor VIIa. Biochem Biophys Res Commun 2016; 470:710-713. [PMID: 26797521 DOI: 10.1016/j.bbrc.2016.01.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 01/11/2016] [Indexed: 12/11/2022]
Abstract
The naturally occurring M358R mutation of the plasma serpin α1-proteinase inhibitor (API) changes both its cleavable reactive centre bond to Arg-Ser and the efficacy with which it inhibits different proteases, reducing the rate of inhibition of neutrophil elastase, and enhancing that of thrombin, factor XIa, and kallikrein, by several orders of magnitude. Although another plasma serpin with an Arg-Ser reactive centre, antithrombin (AT), has been shown to inhibit factor VIIa (FVIIa), no published data are available with respect to FVIIa inhibition by API M358R. Recombinant bacterially-expressed API M358R and plasma-derived AT were therefore compared using gel-based and kinetic assays of FVIIa integrity and activity. Under pseudo-first order conditions of excess serpin over protease, both AT and API M358R formed denaturation-resistant inhibitory complexes with FVIIa in reactions accelerated by TF; AT, but not API M358R, also required heparin for maximal activity. The second order rate constant for heparin-independent API M358R-mediated FVIIa inhibition was determined to be 7.8 ± 0.8 × 10(2) M(-1)sec(-1). We conclude that API M358R inhibits FVIIa by forming inhibitory complexes of the serpin type more rapidly than AT in the absence of heparin. The likely 20-fold excess of API M358R over AT in patient plasma during inflammation raises the possibility that it could contribute to the hemorrhagic tendencies manifested by rare individuals expressing this mutant serpin.
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66
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Azhar A, Khan MS, Swaminathan A, Naseem A, Chatterjee S, Jairajpuri MA. Oxidized antithrombin is a dual inhibitor of coagulation and angiogenesis: Importance of low heparin affinity. Int J Biol Macromol 2016; 82:541-50. [DOI: 10.1016/j.ijbiomac.2015.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/09/2023]
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67
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Gettins PGW, Dolmer K. The High Affinity Binding Site on Plasminogen Activator Inhibitor-1 (PAI-1) for the Low Density Lipoprotein Receptor-related Protein (LRP1) Is Composed of Four Basic Residues. J Biol Chem 2015; 291:800-12. [PMID: 26555266 DOI: 10.1074/jbc.m115.688820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 11/06/2022] Open
Abstract
Plasminogen activator inhibitor 1 (PAI-1) is a serpin inhibitor of the plasminogen activators urokinase-type plasminogen activator (uPA) and tissue plasminogen activator, which binds tightly to the clearance and signaling receptor low density lipoprotein receptor-related protein 1 (LRP1) in both proteinase-complexed and uncomplexed forms. Binding sites for PAI-1 within LRP1 have been localized to CR clusters II and IV. Within cluster II, there is a strong preference for the triple CR domain fragment CR456. Previous mutagenesis studies to identify the binding site on PAI-1 for LRP1 have given conflicting results or implied small binding contributions incompatible with the high affinity PAI-1/LRP1 interaction. Using a highly sensitive solution fluorescence assay, we have examined binding of CR456 to arginine and lysine variants of PAI-1 and definitively identified the binding site as composed of four basic residues, Lys-69, Arg-76, Lys-80, and Lys-88. These are highly conserved among mammalian PAI-1s. Individual mutations result in a 13-800-fold increase in Kd values. We present evidence that binding involves engagement of CR4 by Lys-88, CR5 by Arg-76 and Lys-80, and CR6 by Lys-69, with the strongest interactions to CR5 and CR6. Collectively, the individual binding contributions account quantitatively for the overall PAI-1/LRP1 affinity. We propose that the greater efficiency of PAI-1·uPA complex binding and clearance by LRP1, compared with PAI-1 alone, is due solely to simultaneous binding of the uPA moiety in the complex to its receptor, thereby making binding of the PAI-1 moiety to LRP1 a two-dimensional surface-localized association.
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Affiliation(s)
- Peter G W Gettins
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Klavs Dolmer
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
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68
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Flengsrud R, Antonsen SG. The binding of pentapeptides to biological and synthetic high affinity heparin. Bioorg Med Chem Lett 2015. [PMID: 26216842 DOI: 10.1016/j.bmcl.2015.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Pentapeptides have been shown to bind the synthetic heparin fondaparinux (Arixtra) as well the biological heparins dalteparin (Fragmin) and salmon heparin. In contrast to heparin binding consensus sequences, the pentapeptides are acidic or neutral, with no arginine or histidine residue. The peptides showed an effect on in vitro heparin anti-factor X activity with a reduction of fondaparinux activity by 65-95%. Heparin binding was further studied by using peptide solid phase chromatography and NMR analysis.
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Affiliation(s)
- Ragnar Flengsrud
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), N-1432 Ås, Norway.
| | - Simen Gjelseth Antonsen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), N-1432 Ås, Norway
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69
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Roth R, Swanson R, Izaguirre G, Bock SC, Gettins PGW, Olson ST. Saturation Mutagenesis of the Antithrombin Reactive Center Loop P14 Residue Supports a Three-step Mechanism of Heparin Allosteric Activation Involving Intermediate and Fully Activated States. J Biol Chem 2015; 290:28020-28036. [PMID: 26359493 DOI: 10.1074/jbc.m115.678839] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Indexed: 11/06/2022] Open
Abstract
Past studies have suggested that a key feature of the mechanism of heparin allosteric activation of the anticoagulant serpin, antithrombin, is the release of the reactive center loop P14 residue from a native state stabilizing interaction with the hydrophobic core. However, more recent studies have indicated that this structural change plays a secondary role in the activation mechanism. To clarify this role, we expressed and characterized 15 antithrombin P14 variants. The variants exhibited basal reactivities with factors Xa and IXa, heparin affinities and thermal stabilities that were dramatically altered from wild type, consistent with the P14 mutations perturbing native state stability and shifting an allosteric equilibrium between native and activated states. Rapid kinetic studies confirmed that limiting rate constants for heparin allosteric activation of the mutants were altered in conjunction with the observed shifts of the allosteric equilibrium. However, correlations of the P14 mutations' effects on parameters reflecting the allosteric activation state of the serpin were inconsistent with a two-state model of allosteric activation and suggested multiple activated states. Together, these findings support a minimal three-state model of allosteric activation in which the P14 mutations perturb equilibria involving distinct native, intermediate, and fully activated states wherein the P14 residue retains an interaction with the hydrophobic core in the intermediate state but is released from the core in the fully activated state, and the bulk of allosteric activation has occurred in the intermediate.
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Affiliation(s)
- Ryan Roth
- Center for Molecular Biology of Oral Diseases and Departments of Periodontics
| | - Richard Swanson
- Center for Molecular Biology of Oral Diseases and Departments of Periodontics
| | - Gonzalo Izaguirre
- Center for Molecular Biology of Oral Diseases and Departments of Periodontics
| | - Susan C Bock
- Departments of Medicine and Bioengineering, University of Utah, Salt Lake City, Utah 84132
| | - Peter G W Gettins
- Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Steven T Olson
- Center for Molecular Biology of Oral Diseases and Departments of Periodontics.
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70
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A fast capillary electrophoresis method to assess the binding affinity of recombinant antithrombin toward heparin directly from cell culture supernatants. J Pharm Biomed Anal 2015; 111:64-70. [DOI: 10.1016/j.jpba.2015.02.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 02/13/2015] [Accepted: 02/20/2015] [Indexed: 11/19/2022]
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71
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Boothello RS, Sarkar A, Tran VM, Nguyen TKN, Sankaranarayanan NV, Mehta AY, Alabbas A, Brown S, Rossi A, Joice AC, Mencio CP, Quintero MV, Kuberan B, Desai UR. Chemoenzymatically prepared heparan sulfate containing rare 2-O-sulfonated glucuronic acid residues. ACS Chem Biol 2015; 10:1485-94. [PMID: 25742429 DOI: 10.1021/acschembio.5b00071] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The structural diversity of natural sulfated glycosaminoglycans (GAGs) presents major promise for discovery of chemical biology tools or therapeutic agents. Yet, few GAGs have been identified so far to exhibit this promise. We reasoned that a simple approach to identify such GAGs is to explore sequences containing rare residues, for example, 2-O-sulfonated glucuronic acid (GlcAp2S). Genetic algorithm-based computational docking and filtering suggested that GlcAp2S containing heparan sulfate (HS) may exhibit highly selective recognition of antithrombin, a key plasma clot regulator. HS containing only GlcAp2S and 2-N-sulfonated glucosamine residues, labeled as HS2S2S, was chemoenzymatically synthesized in just two steps and was found to preferentially bind antithrombin over heparin cofactor II, a closely related serpin. Likewise, HS2S2S directly inhibited thrombin but not factor Xa, a closely related protease. The results show that a HS containing rare GlcAp2S residues exhibits the unusual property of selective antithrombin activation and direct thrombin inhibition. More importantly, HS2S2S is also the first molecule to activate antithrombin nearly as well as the heparin pentasaccharide although being completely devoid of the critical 3-O-sulfonate group. Thus, this work shows that novel functions and mechanisms may be uncovered by studying rare GAG residues/sequences.
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Affiliation(s)
- Rio S. Boothello
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Aurijit Sarkar
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | | | | | - Nehru Viji Sankaranarayanan
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - Akul Y. Mehta
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - AlHumaidi Alabbas
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | | | | | | | | | | | | | - Umesh R. Desai
- Institute for Structural Biology & Drug Discovery and Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298, United States
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72
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Baier G, Winzen S, Messerschmidt C, Frank D, Fichter M, Gehring S, Mailänder V, Landfester K. Heparin-based nanocapsules as potential drug delivery systems. Macromol Biosci 2015; 15:765-76. [PMID: 25765603 DOI: 10.1002/mabi.201500035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 02/15/2015] [Indexed: 11/09/2022]
Abstract
Herein, the synthesis and characterization of heparin-based nanocapsules (NCs) as potential drug delivery systems is described. For the synthesis of the heparin-based NCs, the versatile method of miniemulsion polymerization at the droplets interface was achieved resulting in narrowly distributed NCs with 180 nm in diameter. Scanning and transmission electron microscopy images showed clearly NC morphology. A highly negative charge density for the heparin-based NCs was determined by measuring the electro-kinetic potential. Measuring the activated clotting time demonstrated the biological intactness of the polymeric shell. The ability of heparin-based NCs to bind to antithrombin (AT III) was investigated using isothermal titration calorimetry and dynamic light scattering experiments. The chemical stability of the NCs was studied in physiological protein-containing solutions and also in medically interesting fluids such as sodium chloride 0.9%, Ringer's solution, and phosphate buffer saline using dynamic light scattering and measuring the fluorescence intensity. The impressive uptake of NCs in different cells was confirmed by fluorescence-activated cell sorting, confocal laser scanning microscopy, and transmission electron microscopy. The low toxicity of all types of NCs was demonstrated.
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Affiliation(s)
- Grit Baier
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Svenja Winzen
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | | | - Daniela Frank
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Michael Fichter
- University Medicine of the Johannes Gutenberg University, Children's Hospital, Langenbeckstr. 1, Mainz, 55131, Germany
| | - Stephan Gehring
- University Medicine of the Johannes Gutenberg University, Children's Hospital, Langenbeckstr. 1, Mainz, 55131, Germany
| | - Volker Mailänder
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany.,University Medicine of the Johannes Gutenberg University, III. Medical Clinic, Langenbeckstr. 1, Mainz, 55131, Germany
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany.
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73
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Antithrombin concentrates use in children on extracorporeal membrane oxygenation: a retrospective cohort study. Pediatr Crit Care Med 2015; 16:264-9. [PMID: 25581634 DOI: 10.1097/pcc.0000000000000322] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate whether receipt of any antithrombin concentrate improves laboratory and clinical outcomes in children undergoing extracorporeal membrane oxygenation for respiratory failure during their hospitalization compared with those who did not receive antithrombin. DESIGN Retrospective cohort study. SETTING Single, tertiary-care pediatric hospital. PATIENTS Sixty-four neonatal and pediatric patients who underwent extracorporeal membrane oxygenation for respiratory failure between January 2007 and September 2011. INTERVENTION Exposure to any antithrombin concentrate during their extracorporeal membrane oxygenation course compared with similar children who never received antithrombin concentrate. MEASUREMENTS AND MAIN RESULTS Thirty patients received at least one dose of antithrombin during their extracorporeal membrane oxygenation course and 34 patients did not receive any. The median age at admission was less than 1-month old. Age, duration of extracorporeal membrane oxygenation, or first antithrombin level did not differ significantly between the two cohorts. The mean plasma antithrombin level in those who never received antithrombin was 42.2% compared with 66% in those who received it. However, few levels reached the targeted antithrombin level of 120% and those who did fell back to deficient levels within an average of 6.8 hours. For those who received antithrombin concentrate, heparin infusion rates decreased by an average of 10.2 U/kg/hr for at least 12 hours following administration. No statistical differences were noted in the number of extracorporeal membrane oxygenation circuit changes, in vivo clots or hemorrhages, transfusion requirements, hospital or ICU length of stay, or in-hospital mortality. CONCLUSIONS Intermittent, on-demand dosing of antithrombin concentrate in pediatric patients on extracorporeal membrane oxygenation for respiratory failure increased antithrombin levels, but not typically to the targeted level. Patients who received antithrombin concentrate also had decreased heparin requirements for at least 12 hours after dosing. However, no differences were noted in the measured clinical endpoints. A prospective, randomized study of this intervention may require different dosing strategies; such a study is warranted given the unproven efficacy of this costly product.
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74
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Wu M, Wen D, Gao N, Xiao C, Yang L, Xu L, Lian W, Peng W, Jiang J, Zhao J. Anticoagulant and antithrombotic evaluation of native fucosylated chondroitin sulfates and their derivatives as selective inhibitors of intrinsic factor Xase. Eur J Med Chem 2015; 92:257-69. [DOI: 10.1016/j.ejmech.2014.12.054] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 11/25/2022]
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75
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Loeven MA, Rops ALWMM, Berden JHM, Daha MR, Rabelink TJ, van der Vlag J. The role of heparan sulfate as determining pathogenic factor in complement factor H-associated diseases. Mol Immunol 2015; 63:203-8. [DOI: 10.1016/j.molimm.2014.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/27/2014] [Accepted: 08/27/2014] [Indexed: 12/20/2022]
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76
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Lei J, Ding J, Chen Y, Qin W. Potentiometric flow injection sensing system for determination of heparin based on current-controlled release of protamine. Anal Chim Acta 2015; 858:60-5. [DOI: 10.1016/j.aca.2014.12.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/04/2014] [Accepted: 12/09/2014] [Indexed: 11/24/2022]
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77
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Tóth L, Fekete A, Balogh G, Bereczky Z, Komáromi I. Dynamic properties of the native free antithrombin from molecular dynamics simulations: computational evidence for solvent- exposed Arg393 side chain. J Biomol Struct Dyn 2014; 33:2023-36. [PMID: 25483839 DOI: 10.1080/07391102.2014.986525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
While antithrombin (AT) has small basal inhibitory activity, it reaches its full inhibitory potential against activated blood coagulation factors, FXa, FIXa, and FIIa (thrombin), via an allosteric and/or template (bridging) mechanism by the action of heparin, heparan sulfate, or heparin-mimetic pentasaccharides (PS). From the numerous X-ray structures available for different conformational states of AT, only indirect and incomplete conclusions can be drawn on the inherently dynamic properties of AT. As a typical example, the basal inhibitory activity of AT cannot be interpreted on the basis of "non-activated" free antithrombin X-ray structures since the Arg393 side chain, playing crucial role in antithrombin-proteinase interaction, is not exposed. In order to reveal the intrinsic dynamic properties and the reason of basal inhibitory activity of antithrombin, 2 μs molecular dynamics simulations were carried out on its native free-forms. It was shown from the simulation trajectories that the reactive center loop which is functioning as "bait" for proteases, even without any biasing potential can populate conformational state in which the Arg393 side chain is solvent exposed. It is revealed from the trajectory analysis that the peptide sequences correspond to the helix D extension, and new helix P formation can be featured with especially large root-mean-square fluctuations. Mutual information analyses of the trajectory showed remarkable (generalized) correlation between those regions of antithrombin which changed their conformations as the consequence of AT-PS complex formation. This suggests that allosteric information propagation pathways are present even in the non-activated native form of AT.
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Affiliation(s)
- László Tóth
- a Faculty of Medicine, Division of Clinical Laboratory Science, Department of Laboratory Medicine , University of Debrecen , Debrecen , Hungary
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78
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Shenoi RA, Kalathottukaren MT, Travers RJ, Lai BFL, Creagh AL, Lange D, Yu K, Weinhart M, Chew BH, Du C, Brooks DE, Carter CJ, Morrissey JH, Haynes CA, Kizhakkedathu JN. Affinity-based design of a synthetic universal reversal agent for heparin anticoagulants. Sci Transl Med 2014; 6:260ra150. [PMID: 25355700 DOI: 10.1126/scitranslmed.3009427] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heparin-based anticoagulant drugs have been widely used for the prevention of blood clotting during surgical procedures and for the treatment of thromboembolic events. However, bleeding risks associated with these anticoagulants demand continuous monitoring and neutralization with suitable antidotes. Protamine, the only clinically approved antidote to heparin, has shown adverse effects and ineffectiveness against low-molecular weight heparins and fondaparinux, a heparin-related medication. Alternative approaches based on cationic molecules and recombinant proteins have several drawbacks including limited efficacy, toxicity, immunogenicity, and high cost. Thus, there is an unmet clinical need for safer, rapid, predictable, and cost-effective anticoagulant-reversal agents for all clinically used heparins. We report a design strategy for a fully synthetic dendritic polymer-based universal heparin reversal agent (UHRA) that makes use of multivalent presentation of branched cationic heparin binding groups (HBGs). Optimization of the UHRA design was aided by isothermal titration calorimetry studies, biocompatibility evaluation, and heparin neutralization analysis. By controlling the scaffold's molecular weight, the nature of the protective shell, and the presentation of HBGs on the polymer scaffold, we arrived at lead UHRA molecules that completely neutralized the activity of all clinically used heparins. The optimized UHRA molecules demonstrated superior efficacy and safety profiles and mitigated heparin-induced bleeding in animal models. This new polymer therapeutic may benefit patients undergoing high-risk surgical procedures and has potential for the treatment of anticoagulant-related bleeding problems.
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Affiliation(s)
- Rajesh A Shenoi
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Manu Thomas Kalathottukaren
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Richard J Travers
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Benjamin F L Lai
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - A Louise Creagh
- Michael Smith Laboratories, Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Dirk Lange
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Kai Yu
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Marie Weinhart
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Ben H Chew
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Caigan Du
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Donald E Brooks
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada. Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Cedric J Carter
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - James H Morrissey
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Charles A Haynes
- Michael Smith Laboratories, Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jayachandran N Kizhakkedathu
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada. Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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79
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Izaguirre G, Aguila S, Qi L, Swanson R, Roth R, Rezaie AR, Gettins PGW, Olson ST. Conformational activation of antithrombin by heparin involves an altered exosite interaction with protease. J Biol Chem 2014; 289:34049-64. [PMID: 25331949 DOI: 10.1074/jbc.m114.611707] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heparin allosterically activates antithrombin as an inhibitor of factors Xa and IXa by enhancing the initial Michaelis complex interaction of inhibitor with protease through exosites. Here, we investigate the mechanism of this enhancement by analyzing the effects of alanine mutations of six putative antithrombin exosite residues and three complementary protease exosite residues on antithrombin reactivity with these proteases in unactivated and heparin-activated states. Mutations of antithrombin Tyr(253) and His(319) exosite residues produced massive 10-200-fold losses in reactivity with factors Xa and IXa in both unactivated and heparin-activated states, indicating that these residues made critical attractive interactions with protease independent of heparin activation. By contrast, mutations of Asn(233), Arg(235), Glu(237), and Glu(255) exosite residues showed that these residues made both repulsive and attractive interactions with protease that depended on the activation state and whether the critical Tyr(253)/His(319) residues were mutated. Mutation of factor Xa Arg(143), Lys(148), and Arg(150) residues that interact with the exosite in the x-ray structure of the Michaelis complex confirmed the importance of all residues for heparin-activated antithrombin reactivity and Arg(150) for native serpin reactivity. These results demonstrate that the exosite is a key determinant of antithrombin reactivity with factors Xa and IXa in the native as well as the heparin-activated state and support a new model of allosteric activation we recently proposed in which a balance between attractive and repulsive exosite interactions in the native state is shifted to favor the attractive interactions in the activated state through core conformational changes induced by heparin binding.
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Affiliation(s)
- Gonzalo Izaguirre
- From the Department of Periodontics, Center for Molecular Biology of Oral Diseases and
| | - Sonia Aguila
- the Centro Regional de Hemodonación, University of Murcia, Murcia 30003, Spain, and
| | - Lixin Qi
- From the Department of Periodontics, Center for Molecular Biology of Oral Diseases and
| | - Richard Swanson
- From the Department of Periodontics, Center for Molecular Biology of Oral Diseases and
| | - Ryan Roth
- From the Department of Periodontics, Center for Molecular Biology of Oral Diseases and
| | - Alireza R Rezaie
- the Department of Biochemistry and Molecular Biology, St. Louis University, St. Louis, Missouri 63104
| | - Peter G W Gettins
- the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Steven T Olson
- From the Department of Periodontics, Center for Molecular Biology of Oral Diseases and
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80
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Studying glycosaminoglycan-protein interactions using capillary electrophoresis. Methods Mol Biol 2014; 1229:355-75. [PMID: 25325965 DOI: 10.1007/978-1-4939-1714-3_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Methods for studying interactions between glycosaminoglycans (GAGs) and proteins have assumed considerable significance as their biological importance increases. Capillary electrophoresis (CE) is a powerful method to study these interactions due to its speed, high efficiency, and low sample/reagent consumption. In addition, CE works effectively under a wide range of physiologically relevant conditions. This chapter presents state-of-the-art on CE methods for studying GAG-protein interactions including affinity capillary electrophoresis (ACE), capillary zone electrophoresis (CZE), frontal analysis (FA)/frontal analysis continuous capillary electrophoresis (FACCE), and capillary electrokinetic chromatography (CEC) with detailed experimental protocols for ACE and CZE methods.
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81
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Rashid Q, Kapil C, Singh P, Kumari V, Jairajpuri MA. Understanding the specificity of serpin-protease complexes through interface analysis. J Biomol Struct Dyn 2014; 33:1352-62. [PMID: 25052369 DOI: 10.1080/07391102.2014.947525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Serpins such as antithrombin, heparin cofactor II, plasminogen activator inhibitor, antitrypsin, antichymotrypsin, and neuroserpin are involved in important biological processes by inhibiting specific serine proteases. Initially, the protease recognizes the mobile reactive loop of the serpin eliciting conformational changes, where the cleaved loop together with the protease inserts into β-sheet A, translocating the protease to the opposite side of inhibitor leading to its inactivation. Serpin interaction with proteases is governed mainly by the reactive center loop residues (RCL). However, in some inhibitory serpins, exosite residues apart from RCL have been shown to confer protease specificity. Further, this forms the basis of multi-specificity of some serpins, but the residues and their dimension at interface in serpin-protease complexes remain elusive. Here, we present a comprehensive structural analysis of the serpin-protease interfaces using bio COmplexes COntact MAPS (COCOMAPS), PRotein Interface Conservation and Energetics (PRICE), and ProFace programs. We have carried out interface, burial, and evolutionary analysis of different serpin-protease complexes. Among the studied complexes, non-inhibitory serpins exhibit larger interface region with greater number of residue involvement as compared to the inhibitory serpins. On comparing the multi-specific serpins (antithrombin and antitrypsin), a difference in the interface area and residue number was observed, suggestive of a differential mechanism of action of these serpins in regulating their different target proteases. Further, detailed study of these multi-specific serpins listed few essential residues (common in all the complexes) and certain specificity (unique to each complex) determining residues at their interfaces. Structural mapping of interface residues suggested that individual patches with evolutionary conserved residues in specific serpins determine their specificity towards a particular protease.
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Affiliation(s)
- Qudsia Rashid
- a Protein Conformation and Enzymology Lab, Department of Biosciences , Jamia Millia Islamia (A Central University) , New Delhi 110025 , India
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82
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Probing the coagulation pathway with aptamers identifies combinations that synergistically inhibit blood clot formation. ACTA ACUST UNITED AC 2014; 21:935-44. [PMID: 25065530 DOI: 10.1016/j.chembiol.2014.05.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/03/2014] [Accepted: 05/30/2014] [Indexed: 11/21/2022]
Abstract
Coordinated enzymatic reactions regulate blood clot generation. To explore the contributions of various coagulation enzymes in this process, we utilized a panel of aptamers against factors VIIa, IXa, Xa, and prothrombin. Each aptamer dose-dependently inhibited clot formation, yet none was able to completely impede this process in highly procoagulant settings. However, several combinations of two aptamers synergistically impaired clot formation. One extremely potent aptamer combination was able to maintain human blood fluidity even during extracorporeal circulation, a highly procoagulant setting encountered during cardiopulmonary bypass surgery. Moreover, this aptamer cocktail could be rapidly reversed with antidotes to restore normal hemostasis, indicating that even highly potent aptamer combinations can be rapidly controlled. These studies highlight the potential utility of using sets of aptamers to probe the functions of proteins in molecular pathways for research and therapeutic ends.
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83
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Yang L, Dinarvand P, Qureshi SH, Rezaie AR. Engineering D-helix of antithrombin in alpha-1-proteinase inhibitor confers antiinflammatory properties on the chimeric serpin. Thromb Haemost 2014; 112:164-75. [PMID: 24522239 PMCID: PMC4087087 DOI: 10.1160/th13-12-1029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/29/2014] [Indexed: 01/20/2023]
Abstract
Antithrombin (AT) is a heparin-binding serpin in plasma which regulates the proteolytic activity of procoagulant proteases of the clotting cascade. In addition to being an anticoagulant, AT also exhibits antiinflammatory activities when it binds to cell surface heparan sulfate proteoglycans (HSPGs) on the endothelium via its basic residues of D-helix to elicit intracellular signalling responses. By contrast to AT, α1-proteinase inhibitor (α1-PI) is a non-heparin-binding serpin that exhibits very slow reactivity with coagulation proteases and possesses no HSPG-dependent antiinflammatory properties. To determine whether the antiinflammatory signaling specificity of AT can be transferred to α1-PI, we replaced the D-helix of human α1-PI with the corresponding sequence of human AT and expressed the chimeric serpin α1-PI/D-helix) in a bacterial expression system. High molecular weight heparin bound to α1-PI/D-helix and accelerated the inhibition of thrombin by the serpin mutant by a template mechanism reminiscent of the cofactor effect of heparin on inhibition of thrombin by AT. Like AT, α1-PI/D-helix exhibited antiinflammatory properties in both cellular and animal models. Thus, α1-PI/D-helix inhibited the barrier-disruptive effect of proinflammatory cytokines and inhibited the activation of nuclear factor-κB transcription factor in lipopolysaccharide-stimulated endothelial cells by a concentration-dependent manner. Furthermore, the chimeric serpin reduced lipopolysaccharide-mediated lethality, elicited a vascular protective effect and inhibited infiltration of activated leukocytes to the peritoneal cavity of mice in an HMGB1-mediated inflammatory model. These results suggest that grafting the D-helix of AT to α1-PI confers antiinflammatory properties on the serpin and that the chimeric serpin may have therapeutic utility for treating inflammatory disorders.
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Affiliation(s)
| | | | | | - A R Rezaie
- Alireza R. Rezaie, PhD, Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, USA, Tel.: +1 314 977 9240, Fax: +1 314 977 9205 , E-mail:
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84
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Glauser BF, Mourão PAS, Pomin VH. Marine sulfated glycans with serpin-unrelated anticoagulant properties. Adv Clin Chem 2014; 62:269-303. [PMID: 24772670 DOI: 10.1016/b978-0-12-800096-0.00007-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Marine organisms are a rich source of sulfated polysaccharides with unique structures. Fucosylated chondroitin sulfate (FucCS) from the sea cucumber Ludwigothurea grisea and sulfated galactan from the red alga Botryocladia occidentalis are one of these unusual molecules. Besides their uncommon structures, they also exhibit high anticoagulant and antithrombotic effects. Earlier, it was considered that the anticoagulant activities of these two marine glycans were driven mainly by a catalytic serpin-dependent mechanism likewise the mammalian heparins. Its serpin-dependent anticoagulant action relies on promoting thrombin and/or factor Xa inhibition by their specific natural inhibitors (the serpins antithrombin and heparin cofactor II). However, as opposed to heparins, these two previously mentioned marine glycans were proved still capable in promoting coagulation inhibition using serpin-free plasmas. This puzzle observation was further investigated and clearly demonstrated that the cucumber FucCS and the red algal sulfated galactan have an unusual serpin-independent anticoagulant effect by inhibiting the formation of factor Xa and/or thrombin through the procoagulants tenase and prothrombinase complexes, respectively. These marine polysaccharides with unusual anticoagulant effects open clearly new perspectives for the development of new antithrombotic drugs as well as push the glycomics project.
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85
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Liu T, Liu Y, Chen Y, Liu S, Maitz MF, Wang X, Zhang K, Wang J, Wang Y, Chen J, Huang N. Immobilization of heparin/poly-(L)-lysine nanoparticles on dopamine-coated surface to create a heparin density gradient for selective direction of platelet and vascular cells behavior. Acta Biomater 2014; 10:1940-54. [PMID: 24342042 DOI: 10.1016/j.actbio.2013.12.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/22/2013] [Accepted: 12/09/2013] [Indexed: 12/23/2022]
Abstract
Restenosis, thrombosis formation and delayed endothelium regeneration continue to be problematic for coronary artery stent therapy. To improve the hemocompatibility of the cardiovascular implants and selectively direct vascular cell behavior, a novel kind of heparin/poly-l-lysine (Hep/PLL) nanoparticle was developed and immobilized on a dopamine-coated surface. The stability and structural characteristics of the nanoparticles changed with the Hep:PLL concentration ratio. A Hep density gradient was created on a surface by immobilizing nanoparticles with various Hep:PLL ratios on a dopamine-coated surface. Antithrombin III binding quantity was significantly enhanced, and in plasma the APTT and TT times as coagulation tests were prolonged, depending on the Hep density. A low Hep density is sufficient to prevent platelet adhesion and activation. The sensitivity of vascular cells to the Hep density is very different: high Hep density inhibits the growth of all vascular cells, while low Hep density could selectively inhibit smooth muscle cell hyperplasia but promote endothelial progenitor cells and endothelial cell proliferation. These observations provide important guidance for modification of surface heparinization. We suggest that this method will provide a potential means to construct a suitable platform on a stent surface for selective direction of vascular cell behavior with low side effects.
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Affiliation(s)
- Tao Liu
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Yang Liu
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Yuan Chen
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Shihui Liu
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China; Naton Medical Group, Peking 100082, People's Republic of China
| | - Manfred F Maitz
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China; Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials, Hohe Str. 06, 01069 Dresden, Germany
| | - Xue Wang
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Kun Zhang
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Jian Wang
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Yuan Wang
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Junying Chen
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.
| | - Nan Huang
- Key Laboratory of Advanced Technology of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
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86
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Wang L, Cai Y, Jing Y, Zhu B, Zhu L, Xu Y. Route to hemocompatible polyethersulfone membranes via surface aminolysis and heparinization. J Colloid Interface Sci 2014; 422:38-44. [DOI: 10.1016/j.jcis.2014.02.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/01/2014] [Accepted: 02/05/2014] [Indexed: 11/29/2022]
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87
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Zhang F, Moniz HA, Walcott B, Moremen KW, Wang L, Linhardt RJ. Probing the impact of GFP tagging on Robo1-heparin interaction. Glycoconj J 2014; 31:299-307. [PMID: 24748467 PMCID: PMC4118743 DOI: 10.1007/s10719-014-9522-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 03/21/2014] [Accepted: 03/24/2014] [Indexed: 11/26/2022]
Abstract
Green fluorescent proteins (GFPs) and their derivatives are widely used as markers to visualize cells, protein localizations in in vitro and in vivo studies. The use of GFP fusion protein for visualization is generally thought to have negligible effects on cellular function. However, a number of reports suggest that the use of GFP may impact the biological activity of these proteins. Heparin is a glycosaminoglycan (GAG) that interacts with a number of proteins mediating diverse patho-physiological processes. In the heparin-based interactome studies, heparin-binding proteins are often prepared as GFP fusion proteins. In this report, we use surface plasmon resonance (SPR) spectroscopy to study the impact of the GFP tagging on the binding interaction between heparin and a heparin-binding protein, the Roundabout homolog 1 (Robo1). SPR reveals that heparin binds with higher affinity to Robo1 than GFP-tagged Robo1 and through a different kinetic mechanism. A conformational change is observed in the heparin-Robo1 interaction, but not in the heparin-Robo1-GFP interaction. Furthermore the GFP-tagged Robo1 requires a shorter (hexasaccharide) than the tag-free Robo1 (octadecasaccharide). These data demonstrate that GFP tagging can reduce the binding affinity of Robo1 to heparin and hinder heparin binding-induced Robo1 conformation change.
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Affiliation(s)
- Fuming Zhang
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Heather A. Moniz
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Benjamin Walcott
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Kelley W. Moremen
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Lianchun Wang
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Robert J. Linhardt
- Department of Chemical and Biological Engineering, Department of Chemistry and Chemical Biology, Departments of Biology and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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88
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Dinges MM, Solakyildirim K, Larive CK. Affinity capillary electrophoresis for the determination of binding affinities for low molecular weight heparins and antithrombin-III. Electrophoresis 2014; 35:1469-77. [DOI: 10.1002/elps.201300549] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Meredith M. Dinges
- Department of Chemistry; University of California-Riverside; Riverside CA USA
| | - Kemal Solakyildirim
- Department of Chemistry; University of California-Riverside; Riverside CA USA
| | - Cynthia K. Larive
- Department of Chemistry; University of California-Riverside; Riverside CA USA
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89
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Fret Studies of Conformational Changes in Heparin-Binding Peptides. J Fluoresc 2014; 24:885-94. [DOI: 10.1007/s10895-014-1366-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 02/05/2014] [Indexed: 11/27/2022]
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90
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Advantages and pitfalls of combining intravenous antithrombin with nebulized heparin and tissue plasminogen activator in acute respiratory distress syndrome. J Trauma Acute Care Surg 2014; 76:126-33. [PMID: 24368367 DOI: 10.1097/ta.0b013e3182ab0785] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Pulmonary coagulopathy has become an important therapeutic target in adult respiratory distress syndrome (ARDS). We hypothesized that combining intravenous recombinant human antithrombin (rhAT), nebulized heparin, and nebulized tissue plasminogen activator (TPA) more effectively improves pulmonary gas exchange compared with a single rhAT infusion, while maintaining the anti-inflammatory properties of rhAT in ARDS. Therefore, the present prospective, randomized experiment was conducted using an established ovine model. METHODS Following burn and smoke inhalation injury (40% of total body surface area, third-degree flame burn, and 4 × 12 breaths of cold cotton smoke), 18 chronically instrumented sheep were randomly assigned to receive intravenous saline plus saline nebulization (control), intravenous rhAT (6 IU/kg/h) started 1 hour after injury plus saline nebulization (AT i.v.) or intravenous rhAT combined with nebulized heparin (10,000 IU every 4 hours, started 2 hours after injury), and nebulized TPA (2 mg every 4 hours, started 4 hours after injury) (triple therapy, n = 6 each). All animals were mechanically ventilated and fluid resuscitated according to standard protocols during the 48-hour study period. RESULTS Both treatment approaches attenuated ARDS compared with control animals. Notably, triple therapy was associated with an improved PaO2/FiO2 ratio (p = 0.007), attenuated pulmonary obstruction (p = 0.02) and shunting (p = 0.025), as well as reduced ventilatory pressures (p < 0.05 each) versus AT i.v. at 48 hours. However, the anti-inflammatory effects of sole AT i.v., namely, the inhibition of neutrophil activation (neutrophil count in the lymph and pulmonary polymorphonuclear cells, p < 0.05 vs. control each), pulmonary transvascular fluid flux (lymph flow, p = 0.004 vs. control), and systemic vascular leakage (cumulative net fluid balance, p < 0.001 vs. control), were abolished in the triple therapy group. CONCLUSION Combining intravenous rhAT with nebulized heparin and nebulized TPA more effectively restores pulmonary gas exchange, but the anti-inflammatory effects of sole rhAT are abolished with the triple therapy. Interferences between the different anticoagulants may represent a potential explanation for these findings.
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91
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Minsky BB, Zheng B, Dubin PL. Inhibition of antithrombin and bovine serum albumin native state aggregation by heparin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:278-287. [PMID: 24313340 DOI: 10.1021/la4039232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Protein native state aggregation, a major problem in pharmaceutical and biological processes, has been addressed pharmacologically by the addition of protein-binding excipients. Heparin (Hp), a highly sulfated polysaccharide, interacts with numerous proteins with moderate to high affinity, but reports about its effect on protein aggregation are contradictory. We studied the pH dependence of the aggregation of antithrombin (AT) and bovine serum albumin (BSA) in the presence and absence of heparin. High-precision turbidimetry showed strong aggregation for both AT and BSA in I = 10 mM NaCl, conditions at which electrostatically driven Hp binding and aggregation both occur, with more obvious aggregation of heparin-free AT appearing as larger aggregate size. Aggregation of AT was dramatically inhibited at Hp: protein 6:1 (mole ratio); however, the effect at 0.5:1 Hp:protein was greater for BSA. Frontal analysis capillary electrophoresis showed a much larger equilibrium association constant Kobs between Hp and AT, in accord with the onset of Hp binding at a higher pH; both effects are explained by the higher charge density of the positive domain for AT as revealed by modeling with DelPhi. The corresponding modeling images showed that these domains persist at high salt only for AT, consistent with the 160-fold drop in Kobs at 100 mM salt for BSA-Hp binding. The smaller inhibition effect for AT arises from the tendency of its uncomplexed monomer to form larger aggregates more rapidly, but the stronger binding of Hp to AT does not facilitate Hp-induced aggregate dissolution which occurs more readily for BSA. This can be attributed to the higher density of AT aggregates evidenced by higher fractal dimensions. Differences between inhibition and reversal by Hp arise because the former may depend on the stage at which Hp enters the aggregation process and the latter on aggregate size and morphology.
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Affiliation(s)
- Burcu Baykal Minsky
- Department of Chemistry, University of Massachusetts , Amherst, Massachusetts, 01003, United States
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92
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Abstract
Thromboembolic disorders continue to be a major cause of morbidity and mortality, resulting in an increased need for anticoagulant therapy. In recent years, new anticoagulant drugs have been developed at a rapid pace, prompted by the recognition of many undesirable properties of currently used agents, and by a greater knowledge of the active enzymatic sites of clotting factors. Furthermore, the structure of a thrombus is better understood, so that newer drugs can inhibit thrombin or Factor Xa not only on the surface of a thrombus, as in the case of heparin, but also the fibrin-bound thrombin or Factor Xa within the thrombus. These agents are usually small molecules synthesized on the basis of their inhibition of specific active sites in the respective coagulation factors. They possess many improved characteristics, such as greater efficacy and safety, oral administration, reliable pharmacokinetics, less need for laboratory monitoring and minimal interactions with other drugs and diet. Prominent among these are lepuridin (Refludan, Pfizer), fondaparinux (Arixtra, Sanofi-Synthelabo) and ximelagatran (Exanta, Astra Zeneca). However, these new drugs are still far from fulfilling the desired objectives. Most of them possess some but not all of the needed properties. Furthermore, many do not have specific antidotes for immediate reversal of their pharmacologic actions, and all are much more costly than conventional agents. Development of newer agents with properties closer to that of the ideal drug remains a challenge.
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Affiliation(s)
- Hau C Kwaan
- Division of Hematology/Oncology, Northwestern University, Feinberg School of Medicine, 333 East Huron Street, Chicago, IL 60011-3008, USA.
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93
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Wong TE, Huang YS, Weiser J, Brogan TV, Shah SS, Witmer CM. Antithrombin concentrate use in children: a multicenter cohort study. J Pediatr 2013; 163:1329-34.e1. [PMID: 23932317 PMCID: PMC3812320 DOI: 10.1016/j.jpeds.2013.06.036] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 05/24/2013] [Accepted: 06/18/2013] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe the off-label use of antithrombin concentrate in tertiary care pediatric hospitals across the US. STUDY DESIGN This is a retrospective, multicenter, cohort study of 4210 admissions of children younger than 18 years of age who received antithrombin concentrate between 2002 and 2011 within the Pediatric Health Information System administrative database. An on-label admission was defined as an admission with an International Classification of Diseases diagnostic code for a primary hypercoagulable state; admissions without this code were classified as off-label. RESULTS During the 10-year study period, off-label use of antithrombin concentrate increased 5-fold. Overall, 97% of study subjects received antithrombin off-label. Neonates younger than 30 days of age comprised the largest age group (45.7%) of use; 87% of patients had at least one complex chronic condition, with congenital heart/lung defects being the most prevalent primary diagnosis (36.3%). Extracorporeal membrane oxygenation was the most common procedure associated with antithrombin use (43.7%). CONCLUSIONS The off-label use of antithrombin concentrate is increasing rapidly, particularly in critically ill children receiving extracorporeal membrane oxygenation, with few parallel studies to substantiate its safety or efficacy. Further preclinical and controlled clinical studies are critical to expanding our knowledge of this drug. In the meantime, antithrombin concentrate should be used judiciously by clinicians and following guidelines instated by hospitals.
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Affiliation(s)
- Trisha E. Wong
- Puget Sound Blood Center, Seattle, WA,Division of Hematology/Oncology, Department of Pediatrics, Seattle Children’s Hospital, University of Washington, Seattle, WA
| | - Yuan-Shung Huang
- Division of General Pediatrics, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Jason Weiser
- Division of Hospital Medicine, Cincinnati Children’s Hospital and Medical Center, Cincinnati, OH
| | - Thomas V. Brogan
- Division of Critical Care, Department of Pediatrics, Seattle Children’s Hospital, University of Washington, Seattle, WA
| | - Samir S. Shah
- Division of Hospital Medicine, Cincinnati Children’s Hospital and Medical Center, Cincinnati, OH,Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Char M. Witmer
- Division of Hematology, The Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA
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94
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Minsky BB, Nguyen TV, Peyton SR, Kaltashov IA, Dubin PL. Heparin decamer bridges a growth factor and an oligolysine by different charge-driven interactions. Biomacromolecules 2013; 14:4091-8. [PMID: 24107074 DOI: 10.1021/bm401227p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Full-length heparin is widely used in tissue engineering applications due its multiple protein-binding sites that allow it to retain growth factor affinity while associating with oligopeptide components of the tissue scaffold. However, the extent to which oligopeptide coupling interferes with cognate protein binding is difficult to predict. To investigate such simultaneous interactions, we examined a well-defined ternary system comprised of acidic fibroblast growth factor (FGF), tetralysine (K4), with a heparin decamer (dp10) acting as a noncovalent coupler. Electrospray ionization mass spectrometry was used to assess binding affinities and complex stoichiometries as a function of ionic strength for dp10·K4 and FGF·dp10. The ionic strength dependence of K4·dp10 formation is qualitatively consistent with binding driven by the release of condensed counterions previously suggested for native heparin with divalent oligopeptides (Mascotti, D. P.; Lohman, T. M. Biochemistry 1995, 34, 2908-2915). On the other hand, FGF binding displays more complex ionic strength dependence, with higher salt resistance. Remarkably, dp10 that can bind two FGF molecules can only bind one tetralysine. The limited binding of K4 to dp10 suggests that the tetralysine might not block growth factor binding, and the 1:1:1 ternary complex is indeed observed. The analysis of mass distribution of the bound dp10 chains in FGF·dp10, FGF2·dp10, and FGF·dp10·K4 complexes indicated that higher degrees of dp10 sulfation promote the formation of FGF2·dp10 and FGF·dp10·K4. Thus, the selectivity of appropriately chosen short heparin chains could be used to modulate growth factor sequestration and release in a way not feasible with heterogeneous native heparin. In support of this, human hepatocellular carcinoma cells (HEP3Bs) treated with FGF·dp10·K4 were found to exhibit biological activity similar to cells treated with FGF.
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Affiliation(s)
- Burcu Baykal Minsky
- Departments of †Chemistry and ‡Chemical Engineering, University of Massachusetts , 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
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95
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Dementiev A, Swanson R, Roth R, Isetti G, Izaguirre G, Olson ST, Gettins PGW. The allosteric mechanism of activation of antithrombin as an inhibitor of factor IXa and factor Xa: heparin-independent full activation through mutations adjacent to helix D. J Biol Chem 2013; 288:33611-33619. [PMID: 24068708 DOI: 10.1074/jbc.m113.510727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Allosteric conformational changes in antithrombin induced by binding a specific heparin pentasaccharide result in very large increases in the rates of inhibition of factors IXa and Xa but not of thrombin. These are accompanied by CD, fluorescence, and NMR spectroscopic changes. X-ray structures show that heparin binding results in extension of helix D in the region 131-136 with coincident, and possibly coupled, expulsion of the hinge of the reactive center loop. To examine the importance of helix D extension, we have introduced strong helix-promoting mutations in the 131-136 region of antithrombin (YRKAQK to LEEAAE). The resulting variant has endogenous fluorescence indistinguishable from WT antithrombin yet, in the absence of heparin, shows massive enhancements in rates of inhibition of factors IXa and Xa (114- and 110-fold, respectively), but not of thrombin, together with changes in near- and far-UV CD and (1)H NMR spectra. Heparin binding gives only ∼3-4-fold further rate enhancement but increases tryptophan fluorescence by ∼23% without major additional CD or NMR changes. Variants with subsets of these mutations show intermediate activation in the absence of heparin, again with basal fluorescence similar to WT and large increases upon heparin binding. These findings suggest that in WT antithrombin there are two major complementary sources of conformational activation of antithrombin, probably involving altered contacts of side chains of Tyr-131 and Ala-134 with core hydrophobic residues, whereas the reactive center loop hinge expulsion plays only a minor additional role.
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Affiliation(s)
- Alexey Dementiev
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Richard Swanson
- Center for Molecular Biology of Oral Disease, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Ryan Roth
- Center for Molecular Biology of Oral Disease, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Giulia Isetti
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Gonzalo Izaguirre
- Center for Molecular Biology of Oral Disease, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Steven T Olson
- Center for Molecular Biology of Oral Disease, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Peter G W Gettins
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607.
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96
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Sadeghi N, Kahn D, Jeske W, Hoppensteadt D, Fareed J. Tissue factor-mediated activation of the prothrombin complex concentrate (PCC) is differently inhibited by dabigatran, rivaroxaban, and apixaban: potential clinical implication. Clin Appl Thromb Hemost 2013; 19:589-99. [PMID: 23463187 DOI: 10.1177/1076029613479819] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Currently, several newer oral anticoagulants namely dabigatran (anti-IIa), rivaroxaban (anti-Xa), and apixaban are available for various clinical implications. Another oral anti-Xa edoxaban is under development. A parenteral anti-Xa drug namely otamixaban is also under development for cardiovascular interventions. Bleeding complications have been reported in the new oral anticoagulants and have been managed by conventional approaches with limited success. Prothrombin complex concentrates (PCCs) are reported to neutralize the anticoagulant activity of these agents. The PCCs are also able to generate endogenous factor Xa and IIa along with other proteases that are capable of neutralizing the circulating anti-Xa or anti-IIa activities of the newer anticoagulants. The generation of Xa and IIa is also dependent on the type of tissue factor available for their activation. These reported studies suggest that different tissue factors differentially activate a PCC namely Profilnine SD. Furthermore, dabigatran differs from rivaroxaban and other factor Xa inhibitors in its inhibitory profile.
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Affiliation(s)
- Nasiredin Sadeghi
- 1Department of Pathology and Pharmacology, Loyola University Medical Center, Maywood, IL, USA
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97
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Paréj K, Dobó J, Závodszky P, Gál P. The control of the complement lectin pathway activation revisited: both C1-inhibitor and antithrombin are likely physiological inhibitors, while α2-macroglobulin is not. Mol Immunol 2013; 54:415-22. [PMID: 23399388 DOI: 10.1016/j.molimm.2013.01.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 01/11/2013] [Indexed: 12/26/2022]
Abstract
The lectin pathway of complement is an important effector arm of innate immunity. It forms a first line of defense against invading pathogens and dangerously altered self structures. Pattern recognition molecules (mannose-binding lectin (MBL), ficolins) bind to the dangerous particles, which is followed by activation of MBL-associated serine proteases, MASP-1 and MASP-2, resulting in the initiation of the complement cascade. The activation of the lectin pathway is strictly controlled by natural inhibitors, since uncontrolled activation can lead to serious self-tissue damage. Recently we have shown that inhibition of either MASP-1 or MASP-2 by in vitro evolved specific inhibitors completely blocks the lectin pathway in human serum. In this study, we examined the inhibitory action of C1-inhibitor (C1-inh), antithrombin (AT) and α(2)-macroglobulin (α(2)M) on MASP-1 and MASP-2, and studied the inhibition of the lectin pathway in normal human serum in the presence and absence of heparin using C3 and C4 deposition assays. We measured the association rate constants for the serpin/protease reactions. We found that in the presence of heparin both C1-inh and AT are equally efficient inhibitors of the lectin pathway. Although α(2)M formed complex with MASP-1 in fluid phase, it could not abolish lectin pathway activation on activator surfaces.
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Affiliation(s)
- Katalin Paréj
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Karolina út 29, Budapest H-1113, Hungary
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98
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Affinity capillary electrophoresis in binding study of antithrombin to heparin from different sources. Talanta 2013; 105:366-71. [DOI: 10.1016/j.talanta.2012.10.057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/12/2012] [Accepted: 10/18/2012] [Indexed: 11/16/2022]
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99
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Lima MA, Hughes AJ, Veraldi N, Rudd TR, Hussain R, Brito AS, Chavante SF, Tersariol II, Siligardi G, Nader HB, Yates EA. Antithrombin stabilisation by sulfated carbohydrates correlates with anticoagulant activity. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00048f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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100
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Tang Z, Li D, Liu X, Wu Z, Liu W, Brash JL, Chen H. Vinyl-monomer with lysine side chains for preparing copolymer surfaces with fibrinolytic activity. Polym Chem 2013. [DOI: 10.1039/c2py20944f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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