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Lu Y, Villoutreix BO, Biswas I, Ding Q, Wang X, Rezaie AR. Antithrombin Resistance Rescues Clotting Defect of Homozygous Prothrombin-Y510N Dysprothrombinemia. Thromb Haemost 2021; 122:679-691. [PMID: 34256393 PMCID: PMC8755856 DOI: 10.1055/a-1549-6407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A patient with hematuria in our clinic was diagnosed with urolithiasis. Analysis of the patient's plasma clotting time indicated that both activated partial thromboplastin time (52.6 seconds) and prothrombin time (19.4 seconds) are prolonged and prothrombin activity is reduced to 12.4% of normal, though the patient exhibited no abnormal bleeding phenotype and a prothrombin antigen level of 87.9%. Genetic analysis revealed the patient is homozygous for prothrombin Y510N mutation. We expressed and characterized the prothrombin-Y510N variant in appropriate coagulation assays and found that the specificity constant for activation of the mutant zymogen by factor Xa is impaired approximately fivefold. Thrombin generation assay using patient's plasma and prothrombin-deficient plasma supplemented with either wild-type or prothrombin-Y510N revealed that both peak height and time to peak for the prothrombin mutant are decreased; however, the endogenous thrombin generation potential is increased. Further analysis indicated that the thrombin mutant exhibits resistance to antithrombin and is inhibited by the serpin with approximately 12-fold slower rate constant. Protein C activation by thrombin-Y510N was also decreased by approximately 10-fold; however, thrombomodulin overcame the catalytic defect. The Na+-concentration-dependence of the amidolytic activities revealed that the dissociation constant for the interaction of Na+ with the mutant has been elevated approximately 20-fold. These results suggest that Y510 (Y184a in chymotrypsin numbering) belongs to network of residues involved in binding Na+. A normal protein C activation by thrombin-Y510N suggests that thrombomodulin modulates the conformation of the Na+-binding loop of thrombin. The clotting defect of thrombin-Y510N appears to be compensated by its markedly lower reactivity with antithrombin, explaining patient's normal hemostatic phenotype.
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Affiliation(s)
- Yeling Lu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States.,Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bruno O Villoutreix
- INSERM 1141, NeuroDiderot, Université de Paris, Hôpital Robert-Debré, Paris, France
| | - Indranil Biswas
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Alireza R Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States.,Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
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Lu Y, Biswas I, Villoutreix BO, Rezaie AR. Role of Gly197 in the structure and function of protein C. Biochim Biophys Acta Gen Subj 2021; 1865:129892. [PMID: 33722640 DOI: 10.1016/j.bbagen.2021.129892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/27/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
We previously demonstrated that heterozygous Gly197 to Arg mutation in PROC is associated with venous thrombosis due to the mutation abrogating both zymogenic and enzymatic activities of protein C and activated protein C (APC). In this study, we investigated the role of Gly197 on the structure and function of protein C by replacing it with Ala, Lys and Glu in separate constructs. Characterization of protein C mutants indicated their activation by thrombin is improved ~5-20-fold with the order of PC-G197K > PC-G197E > PC-G197A > PC-WT. Interestingly, the cofactor function of thrombomodulin (TM) in promoting the activation of zymogens by thrombin followed the reverse order of PC-WT > PC-G197A > PC-G197E > PC-G197K. The thrombin-generation inhibitory profiles of zymogens in a tissue factor-mediated thrombin generation assay using protein C-deficient plasma with or without supplementation with TM followed the same order of zymogen activation in the purified system. Evaluation of anticoagulant activities of APC derivatives by prothrombinase and aPTT assays revealed a normal activity for APC-G197A but dramatically impaired activity for the other two mutants. In the endothelial cell permeability assay, APC-G197A exhibited normal antiinflammatory activity, but the other two mutants were nearly inactive. These results suggest that Gly197 plays a key role in TM cofactor-dependent protein C activation by thrombin. It facilitates the recognition of protein C by thrombin in the presence of TM but impedes it in the absence of the cofactor. In APC, a small residue at this position is required for the proper folding/reactivity of the active-site pocket of the protease, a hypothesis supported by structural modeling.
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Affiliation(s)
- Yeling Lu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, United States of America; Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Indranil Biswas
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, United States of America
| | - Bruno O Villoutreix
- INSERM 1141, NeuroDiderot, Université de Paris, Hôpital Robert-Debré, F-75019 Paris, France
| | - Alireza R Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, United States of America; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America.
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Gordienko MG, Palchikova VV, Kalenov SV, Lebedev EA, Belov AA, Menshutina NV. The alginate–chitosan composite sponges with biogenic Ag nanoparticles produced by combining of cryostructuration, ionotropic gelation and ion replacement methods. INT J POLYM MATER PO 2020. [DOI: 10.1080/00914037.2020.1798439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Mariia G. Gordienko
- International Science and Education Centre for Transfer of Biopharmaceutical Technologies, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
| | - Vera V. Palchikova
- International Science and Education Centre for Transfer of Biopharmaceutical Technologies, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
| | - Sergei V. Kalenov
- Biotechnology Department, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
| | - Evgeniy A. Lebedev
- International Science and Education Centre for Transfer of Biopharmaceutical Technologies, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
| | - Alexei A. Belov
- Biotechnology Department, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
| | - Natalia V. Menshutina
- International Science and Education Centre for Transfer of Biopharmaceutical Technologies, D.I. Mendeleyev University of Chemical-Technology of Russia, Moscow, Russian Federation
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Lu Y, Giri H, Villoutreix BO, Ding Q, Wang X, Rezaie AR. Gly197Arg mutation in protein C causes recurrent thrombosis in a heterozygous carrier. J Thromb Haemost 2020; 18:1141-1153. [PMID: 32078247 PMCID: PMC7192786 DOI: 10.1111/jth.14777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Activated protein C (APC) downregulates thrombin generation by inactivating procoagulant cofactors Va and VIIIa by limited proteolysis. We identified two protein C-deficient patients both of whom carry a heterozygous Gly197 to Arg (G197R) mutation in PROC and experience venous thrombosis. OBJECTIVE The objective of this study was to determine the molecular basis of the clotting defect in patients carrying the G197R mutation. METHODS We expressed protein C-G197R in mammalian cells and characterized its properties in established coagulation and anti-inflammatory assay systems. RESULTS The activation of protein C-G197R by thrombin was improved ~10-fold; however, its activation by thrombin was not promoted by thrombomodulin (TM). In a tissue factor-mediated thrombin generation assay, the addition of soluble TM to protein C-deficient plasma, supplemented with protein C-G197R, did not have a significant inhibitory effect on thrombin generation parameters. APC-G197R did not exhibit a significant anticoagulant activity in either purified or plasma-based assay systems. APC-G197R was essentially inactive because it showed no activity in an aPTT assay. Anti-inflammatory activity of APC-G197R was also dramatically impaired as determined by an endothelial cell permeability assay. Structural modeling predicted that the side-chain of Arg cannot be accommodated at this site of APC without a major distortion of the local structure that appears to propagate and adversely affect the reactivity/folding of the catalytic pocket. CONCLUSION The G197R mutation in patients appears to be functionally equivalent to a heterozygous protein C knockout with half of the protein having no significant activity and thus causing thrombosis.
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Affiliation(s)
- Yeling Lu
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City
| | - Hemant Giri
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City
| | - Bruno O. Villoutreix
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000 Lille, France
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Alireza R. Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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Reshetnyak VI, Maev IV, Reshetnyak TM, Zhuravel SV, Pisarev VM. Liver Disease and Hemostasis (Review) Part 2. Cholestatic Liver Disease and Hemostasis. ACTA ACUST UNITED AC 2019. [DOI: 10.15360/1813-9779-2019-6-80-93] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The presence or development of liver disorders can significantly complicate the course of critical illness and terminal conditions. Systemic hemostatic disorders are common in Intensive Care Units patients with cholestatic liver diseases, so the study of the mechanisms of their development can contribute to the understanding of the development of multiorgan failure in critical illness.The review discusses current data on changes in hemostatic parameters in patients with cholestatic liver diseases, proposes a mechanism for the development of such disorders, which involve interactions of phospholipids with platelet and endotheliocyte membranes. It is suggested that a trend for thrombosis in patients with cholestatic liver disease is due to increased accumulation of bile acids in the systemic circulation. Available data demonstrate that the antiphospholipid syndrome may predispose to the formation of blood clots due to alterations of phospholipid composition of membranes of platelets and vascular endothelial cells by circulating antiphospholipid antibodies. Clarifying the mechanisms contributing to changes of the blood coagulation system parameters in liver disorders will aid to development of optimal correction of hemostatic disorders in patients with chronic liver diseases.
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Affiliation(s)
- Vasiliy I. Reshetnyak
- A. I. Evdokimov Moscow State University of medicine and dentistry, Ministry of Health of Russia
| | - Igor V. Maev
- A. I. Evdokimov Moscow State University of medicine and dentistry, Ministry of Health of Russia
| | | | - Sergei V. Zhuravel
- N. V. Sklifosovsky Research Institute of Emergency Care, Moscow Healthcare Department
| | - Vladimir M. Pisarev
- V. A. Negovsky Research Institute of General Reanimatology, Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology
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Lu Y, Mehta-D'souza P, Biswas I, Villoutreix BO, Wang X, Ding Q, Rezaie AR. Ile73Asn mutation in protein C introduces a new N-linked glycosylation site on the first EGF-domain of protein C and causes thrombosis. Haematologica 2019; 105:1712-1722. [PMID: 31399531 PMCID: PMC7271577 DOI: 10.3324/haematol.2019.227033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/07/2019] [Indexed: 12/24/2022] Open
Abstract
Activated protein C exerts its anticoagulant activity by protein S-dependent inactivation of factors Va and VIIIa by limited proteolysis. We identified a venous thrombosis patient who has plasma protein C antigen level of 63% and activity levels of 44% and 23%, as monitored by chromogenic and clotting assays. Genetic analysis revealed the proband carries compound heterozygous mutations (c.344T>A, p.I73N and c.1181G>A, p.R352Q) in PROC. We individually expressed protein C mutations and discovered that thrombin-thrombomodulin activates both variants normally and the resulting activated protein C mutants exhibit normal amidolytic and proteolytic activities. However, while protein S-dependent catalytic activity of activated protein C-R352Q toward factor Va was normal, it was significantly impaired for activated protein C-I73N. These results suggest that the Ile to Asn substitution impairs interaction of activated protein C-I73N with protein S. This conclusion was supported by a normal anticoagulant activity for activated protein C-I73N in protein S-deficient but not in normal plasma. Further analysis revealed Ile to Asn substitution introduces a new glycosylation site on first EGF-like domain of protein C, thereby adversely affecting interaction of activated protein C with protein S. Activated protein C-R352Q only exhibited reduced activity in sub-physiological concentrations of Na+ and Ca2+, suggesting that this residue contributes to metal ion-binding affinity of the protease, with no apparent adverse effect on its function in the presence of physiological levels of metal ions. These results provide insight into the mechanism by which I73N/R352Q mutations in activated protein C cause thrombosis in proband carrying this compound heterozygous mutation.
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Affiliation(s)
- Yeling Lu
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Padmaja Mehta-D'souza
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Indranil Biswas
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Bruno O Villoutreix
- Université Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000 Lille, France
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Alireza R Rezaie
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA .,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Afosah DK, Verespy S, Al-Horani RA, Boothello RS, Karuturi R, Desai UR. A small group of sulfated benzofurans induces steady-state submaximal inhibition of thrombin. Bioorg Med Chem Lett 2018; 28:1101-1105. [PMID: 29459207 DOI: 10.1016/j.bmcl.2018.01.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 01/07/2023]
Abstract
Despite the development of promising direct oral anticoagulants, which are all orthosteric inhibitors, a sizable number of patients suffer from bleeding complications. We have hypothesized that allosterism based on the heparin-binding exosites presents a major opportunity to induce sub-maximal inhibition of coagulation proteases, thereby avoiding/reducing bleeding risk. We present the design of a group of sulfated benzofuran dimers that display heparin-binding site-dependent partial allosteric inhibition of thrombin against fibrinogen (ΔY = 55-75%), the first time that a small molecule (MW < 800) has been found to thwart macromolecular cleavage by a monomeric protease in a controlled manner. The work leads to the promising concept that it should be possible to develop allosteric inhibitors that reduce clotting, but do not completely eliminate it, thereby avoiding major bleeding complications that beset anticoagulants today.
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Affiliation(s)
- Daniel K Afosah
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA; Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Stephen Verespy
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA; Department of Chemistry, Virginia Commonwealth University, Richmond, VA, USA
| | - Rami A Al-Horani
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA; Division of Basic Pharmaceutical Sciences, Xavier University, New Orleans, LA, USA
| | - Rio S Boothello
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Rajesh Karuturi
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Umesh R Desai
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA; Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA.
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8
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Wang C, Luo W, Li P, Li S, Yang Z, Hu Z, Liu Y, Ao N. Preparation and evaluation of chitosan/alginate porous microspheres/Bletilla striata polysaccharide composite hemostatic sponges. Carbohydr Polym 2017; 174:432-442. [DOI: 10.1016/j.carbpol.2017.06.112] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/25/2017] [Accepted: 06/28/2017] [Indexed: 10/19/2022]
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Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin. Sci Rep 2016; 6:24043. [PMID: 27053426 PMCID: PMC4823711 DOI: 10.1038/srep24043] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/14/2016] [Indexed: 11/26/2022] Open
Abstract
Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (<500 nM) and high selectivity for thrombin (>150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80–100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding.
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10
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Görar S, Ademoğlu E, Çarlıoğlu A, Alioğlu B, Bekdemir H, Sağlam B, Candan Z, Üçler R, Culha C, Aral Y. Low levels of circulating platelet factor 4 (PF4, CXCL4) in subclinically hypothyroid autoimmune thyroiditis. J Endocrinol Invest 2016; 39:185-9. [PMID: 26142741 DOI: 10.1007/s40618-015-0348-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 06/22/2015] [Indexed: 01/23/2023]
Abstract
PURPOSE Chemokines play an important role in the pathogenesis of autoimmune thyroid diseases. Platelet factor 4 (PF4, CXCL4) released from activated platelets is a chemokine. However, its clinical importance in autoimmune thyroiditis remains unknown. This study is intended to determine circulating levels of PF4 levels in patients with autoimmune thyroiditis (AIT). METHODS Circulating levels of PF4 were measured in 34 consecutive patients with newly diagnosed AIT and 18 euthyroid controls. Among AIT group, 16 patients were euthyroid and 18 had subclinic hypothyroidism. Controls and individuals with AIT were similar in terms of age. RESULTS Serum levels of PF4 were comparable in patients with AIT and in controls. Among patients with AIT, PF4 was significantly lower in those with subclinical hypothyroidism than in euthyroid individuals (p = 0.001). In correlation analysis, PF4 was negatively correlated with TSH (r = -0.663, p = 0.000) and positively correlated with free T4 (r = 0.428, p = 0.012). There was not any significant correlation between PF4 and AbTPO, AbTg. CONCLUSION The present study demonstrated for the first time that circulating PF4 levels are decreased in subclinically hypothyroid AIT. This result draws attention to the circulating PF4 levels in subclinically hypothyroid AIT and may shed light on further researches at this topic.
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Affiliation(s)
- S Görar
- Department of Endocrinology and Metabolism, Antalya Training and Research Hospital, Antalya, Turkey.
| | - E Ademoğlu
- Department of Endocrinology and Metabolism, Ankara Training and Research Hospital, Ankara, Turkey
| | - A Çarlıoğlu
- Department of Internal Medicine, Erzurum Training and Research Hospital, Erzurum, Turkey
| | - B Alioğlu
- Director of Hematology Laboratories, Department of Pediatric Hematology, Ankara Training and Research Hospital, Ankara, Turkey
| | - H Bekdemir
- Department of Endocrinology and Metabolism, Ankara Training and Research Hospital, Ankara, Turkey
| | - B Sağlam
- Hematology Laboratories, Ankara Training and Research Hospital, Ankara, Turkey
| | - Z Candan
- Department of Endocrinology and Metabolism, Ankara Training and Research Hospital, Ankara, Turkey
| | - R Üçler
- Department of Endocrinology and Metabolism, Faculty of Medicine, Van Yuzuncu Yıl University, Van, Turkey
| | - C Culha
- Department of Endocrinology and Metabolism, Ankara Training and Research Hospital, Ankara, Turkey
| | - Y Aral
- Department of Endocrinology and Metabolism, Ankara Training and Research Hospital, Ankara, Turkey
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Mehta AY, Thakkar JN, Mohammed BM, Martin EJ, Brophy DF, Kishimoto T, Desai UR. Targeting the GPIbα binding site of thrombin to simultaneously induce dual anticoagulant and antiplatelet effects. J Med Chem 2014; 57:3030-9. [PMID: 24635452 PMCID: PMC4203406 DOI: 10.1021/jm4020026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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Exosite 2 of human thrombin contributes
to two opposing pathways, the anticoagulant pathway and the platelet
aggregation pathway. We reasoned that an exosite 2 directed allosteric
thrombin inhibitor should simultaneously induce anticoagulant and
antiplatelet effects. To assess this, we synthesized SbO4L based on
the sulfated tyrosine-containing sequence of GPIbα. SbO4L was
synthesized in three simple steps in high yield and found to be a
highly selective, direct inhibitor of thrombin. Michelis–Menten
kinetic studies indicated a noncompetitive mechanism of inhibition.
Competitive inhibition studies suggested ideal competition with heparin
and glycoprotein Ibα, as predicted. Studies with site-directed
mutants of thrombin indicated that SbO4L binds to Arg233, Lys235,
and Lys236 of exosite 2. SbO4L prevented thrombin-mediated platelet
activation and aggregation as expected on the basis of competition
with GPIbα. SbO4L presents a novel paradigm of simultaneous
dual anticoagulant and antiplatelet effects achieved through the GPIbα
binding site of thrombin.
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Affiliation(s)
- Akul Y Mehta
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University , Richmond, Virginia 23219, United States
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12
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Role of platelet chemokines, PF-4 and CTAP-III, in cancer biology. J Hematol Oncol 2013; 6:42. [PMID: 23800319 PMCID: PMC3694472 DOI: 10.1186/1756-8722-6-42] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 06/13/2013] [Indexed: 12/31/2022] Open
Abstract
With the recent addition of anti-angiogenic agents to cancer treatment, the angiogenesis regulators in platelets are gaining importance. Platelet factor 4 (PF-4/CXCL4) and Connective tissue activating peptide III (CTAP-III) are two platelet-associated chemokines that modulate tumor angiogenesis, inflammation within the tumor microenvironment, and in turn tumor growth. Here, we review the role of PF-4 and CTAP-III in the regulation of tumor angiogenesis; the results of clinical trial using recombinant PF-4 (rPF-4); and the use of PF-4 and CTAP-III as cancer biomarkers.
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13
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Sidhu PS, Abdel Aziz MH, Sarkar A, Mehta AY, Zhou Q, Desai UR. Designing allosteric regulators of thrombin. Exosite 2 features multiple subsites that can be targeted by sulfated small molecules for inducing inhibition. J Med Chem 2013; 56:5059-70. [PMID: 23718540 DOI: 10.1021/jm400369q] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We recently designed a group of novel exosite-2-directed sulfated, small, allosteric inhibitors of thrombin. To develop more potent inhibitors, monosulfated benzofuran tri- and tetrameric homologues of the parent designed dimers were synthesized in seven to eight steps and found to exhibit a wide range of potencies. Among these, trimer 9a was found to be nearly 10-fold more potent than the first generation molecules. Michaelis-Menten studies indicated an allosteric mechanism of inhibition. Competitive studies using a hirudin peptide (exosite 1 ligand) and unfractionated heparin, heparin octasaccharide, and γ'-fibrinogen peptide (exosite 2 ligands) demonstrated exosite 2 recognition in a manner different from that of the parent dimers. Alanine scanning mutagenesis of 12 Arg/Lys residues of exosite 2 revealed a defect in 9a potency for Arg233Ala thrombin only confirming the major difference in site of recognition between the two structurally related sulfated benzofurans. The results suggest that multiple avenues are available within exosite 2 for inducing thrombin inhibition.
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Affiliation(s)
- Preetpal Singh Sidhu
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23219, USA
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Ding Q, Yang L, Hassanian SM, Rezaie AR. Expression and functional characterisation of natural R147W and K150del variants of protein C in the Chinese population. Thromb Haemost 2013; 109:614-24. [PMID: 23389250 DOI: 10.1160/th12-10-0760] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/06/2013] [Indexed: 01/19/2023]
Abstract
Protein C is a vitamin K-dependent serine protease zymogen in plasma which upon activation to activated protein C (APC) by thrombin down-regulates the clotting cascade by limited proteolysis of the procoagulant cofactors Va and VIIIa. In addition to its anticoagulant activity, APC also exhibits potent cytoprotective and anti-inflammatory activities. While the anticoagulant activity of APC is enhanced by the cofactor function of protein S on membrane phospholipids, the cytoprotective intracellular signalling activity of APC requires complex formation with endothelial protein C receptor (EPCR) expressed on the vascular endothelium. Two natural variants of APC [Arg-147 to Trp substitution (R147W) and Lys-150 deletion (K150del)] have been identified in the Chinese population as hotspot mutants occurring with high frequencies of 27.8% and 13.9%, respectively, among 36 protein C-deficient subjects. The affected individuals exhibit variable thrombotic tendencies. To understand the underlying cause of the thrombotic phenotype in these patients, we expressed these two protein C variants in mammalian cells and characterised their anticoagulant and anti-inflammatory properties using established in vitro and cellular assays. Our results suggest that both R147W and K150del variants have normal amidolytic and proteolytic activities in the absence of cofactors. However, the R147W mutant exhibits ~3 times lower affinity for binding to EPCR and the K150del variant has ~2-3-fold impaired anticoagulant activity in the presence of protein S. These results provide some insight into the possible pathogenic mechanism of protein C deficiency in Chinese patients carrying these mutations.
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Affiliation(s)
- Qiulan Ding
- 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
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Abdel Aziz MH, Sidhu PS, Liang A, Kim JY, Mosier PD, Zhou Q, Farrell DH, Desai UR. Designing allosteric regulators of thrombin. Monosulfated benzofuran dimers selectively interact with Arg173 of exosite 2 to induce inhibition. J Med Chem 2012; 55:6888-97. [PMID: 22788964 DOI: 10.1021/jm300670q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Earlier, we reported on the design of sulfated benzofuran dimers (SBDs) as allosteric inhibitors of thrombin (Sidhu et al. J. Med. Chem.201154 5522-5531). To identify the site of binding of SBDs, we studied thrombin inhibition in the presence of exosite 1 and 2 ligands. Whereas hirudin peptide and heparin octasaccharide did not affect the IC(50) of thrombin inhibition by a high affinity SBD, the presence of full-length heparin reduced inhibition potency by 4-fold. The presence of γ' fibrinogen peptide, which recognizes Arg93, Arg97, Arg173, Arg175, and other residues, resulted in a loss of affinity that correlated with the ideal Dixon-Webb competitive profile. Replacement of several arginines and lysines of exosite 2 with alanine did not affect thrombin inhibition potency, except for Arg173, which displayed a 22-fold reduction in IC(50). Docking studies suggested a hydrophobic patch around Arg173 as a plausible site of SBD binding to thrombin. The absence of the Arg173-like residue in factor Xa supported the observed selectivity of inhibition by SBDs. Cellular toxicity studies indicated that SBDs are essentially nontoxic to cells at concentrations as high as 250 mg/kg. Overall, the work presents the localization of the SBD binding site, which could lead to allosteric modulators of thrombin that are completely different from all clinically used anticoagulants.
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Affiliation(s)
- May H Abdel Aziz
- Department of Medicinal Chemistry and ‡Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University , Richmond, Virginia 23219, United States
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16
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Abdel Aziz MH, Mosier PD, Desai UR. Identification of the site of binding of sulfated, low molecular weight lignins on thrombin. Biochem Biophys Res Commun 2011; 413:348-52. [PMID: 21893043 PMCID: PMC3183121 DOI: 10.1016/j.bbrc.2011.08.102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 08/20/2011] [Indexed: 10/17/2022]
Abstract
Sulfated, low molecular weight lignins (LMWLs), designed recently as macromolecular mimetics of the low molecular weight heparins (LMWHs), were found to exhibit a novel allosteric mechanism of inhibition of human thrombin, factor Xa and plasmin, which translates into potent human blood anticoagulation potential. To identify the site of binding of sulfated LMWLs, a panel of site-directed thrombin mutants was studied. Substitution of alanine for Arg(93) or Arg(175) induced a 7-8-fold decrease in inhibition potency, while Arg(165)Ala, Lys(169)Ala, Arg(173)Ala and Arg(233)Ala thrombin mutants displayed a 2-4-fold decrease. Other exosite 2 residues including those that play an important role in heparin binding, such as Arg(101), Lys(235), Lys(236) and Lys(240), did not induce any deficiency in sulfated LMWL activity. Thrombin mutants with multiple alanine substitution of basic residues showed a progressively greater defect in inhibition potency. Comparison of thrombin, factor Xa, factor IXa and factor VIIa primary sequences reiterated Arg(93) and Arg(175) as residues likely to be targeted by sulfated LMWLs. The identification of a novel site on thrombin with capability of allosteric modulation is expected to greatly assist the design of new regulators based on the sulfated LMWL scaffold.
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Affiliation(s)
- May H. Abdel Aziz
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298
| | - Philip D. Mosier
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298
| | - Umesh R. Desai
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298
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Thachil J. The prothrombotic potential of platelet factor 4. Eur J Intern Med 2010; 21:79-83. [PMID: 20206875 DOI: 10.1016/j.ejim.2009.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 10/27/2009] [Accepted: 11/15/2009] [Indexed: 11/15/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder initiated by heparin administration. It is caused by the formation of pathogenic antibodies to complexes of platelet factor-4 (PF4) and heparin on platelet surfaces that cause platelet activation, aggregation and thrombosis. There has been intense research on this intriguing, drug-related thrombocytopenia explaining several characteristic aspects of this condition. However, prothrombotic potential of the key player, PF4 has not been investigated in many studies although it has been shown to be critical in monocyte chemotaxis, monocyte-platelet interaction, and megakaryocyte suppression, all of which can contribute to the pathophysiology of HIT. This article explains the important role of PF4 released during platelet activation with the administration of heparin in the pathogenesis of thrombocytopenia and thrombosis in HIT.
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Fiore MM, Mackie IM. Mechanism of low-molecular-weight heparin reversal by platelet factor 4. Thromb Res 2009; 124:149-55. [DOI: 10.1016/j.thromres.2008.12.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 12/17/2008] [Accepted: 12/23/2008] [Indexed: 10/21/2022]
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Rezaie AR, Bae JS, Manithody C, Qureshi SH, Yang L. Protein Z-dependent protease inhibitor binds to the C-terminal domain of protein Z. J Biol Chem 2008; 283:19922-6. [PMID: 18502758 PMCID: PMC2459281 DOI: 10.1074/jbc.m802639200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 05/16/2008] [Indexed: 11/06/2022] Open
Abstract
Protein Z (PZ) is a multidomain vitamin K-dependent plasma protein that functions as a cofactor to promote the inactivation of factor Xa (fXa) by PZ-dependent protease inhibitor (ZPI) by three orders of magnitude. To understand the mechanism by which PZ improves the reactivity of fXa with ZPI, we expressed wild-type PZ, PZ lacking the gamma-carboxyglutamic acid domain (GD-PZ), and a chimeric PZ mutant in which both Gla and EGF-like domains of the molecule were substituted with identical domains of fXa. The ZPI binding and the cofactor function of the PZ derivatives were characterized in both binding and kinetic assays. The binding assay indicated that all PZ derivatives interact with ZPI with a similar dissociation constant (K(D)) of approximately 7 nm. However, the apparent K(D) for the chimeric PZ-mediated ZPI inhibition of fXa was elevated 6-fold on PC/PS vesicles and its capacity to function as a cofactor to accelerate the ZPI inhibition of fXa was also decreased 6-fold. The cofactor activity of GD-PZ was dramatically impaired; however, the deletion mutant exhibited a normal cofactor function in solution. A chimeric activated protein C mutant containing the Gla domain of fXa was susceptible to inhibition by ZPI in the presence of PZ. These results suggest that: (i) the ZPI interactive site of PZ is located within the C-terminal domain of the cofactor and (ii) a specific interaction between the Gla domains of PZ and fXa contributes approximately 6-fold to the acceleration of the ZPI inhibition of fXa on phospholipid membranes.
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Affiliation(s)
- Alireza R Rezaie
- Edward A Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.
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