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Huang J, Shi X, Xi W, Liu P, Long Z, Xi X. Evaluation of targeting c-Src by the RGT-containing peptide as a novel antithrombotic strategy. J Hematol Oncol 2015; 8:62. [PMID: 26025329 PMCID: PMC4459659 DOI: 10.1186/s13045-015-0159-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/22/2015] [Indexed: 01/18/2023] Open
Abstract
Background Interaction of integrin β3 with c-Src plays critical roles in cellular signaling which is heavily implicated in platelet adhesion and aggregation, as well as in tumor cell proliferation and metastasis or in osteoclastic bone resorption. Selectively blocking integrin αIIbβ3 outside-in signaling in platelets has been a focus of attention because of its effective antithrombotic potential together with a sufficient hemostatic capacity. The myristoylated RGT peptide has been shown to achieve this blockade by targeting the association of c-Src with the integrin β3 tail, but the lack of key information regarding the mechanisms of action prevents this strategy from being further developed into practical antithrombotics. Therefore, in-depth knowledge of the precise mechanisms for RGT peptide in regulating platelet function is needed to establish the basis for a potential antithrombotic therapy by targeting c-Src. Methods The reduction-sensitive peptides were applied to rule out the membrane anchorage after cytoplasmic delivery. The c-Src activity was assayed at living cell or at protein levels to assess the direct effect of RGT targeting on c-Src. Thrombus formation under flow in the presence of cytoplasmic RGT peptide was observed by perfusing whole blood through the collagen-coated micro-chamber. Results The RGT peptide did not depend on the membrane anchorage to inhibit outside-in signaling in platelets. The myr-AC ~ CRGT peptide readily blocked agonist-induced c-Src activation by disrupting the Src/β3 association and inhibited the RhoA activation and collagen-induced platelet aggregation in addition to the typical outside-in signaling events. The myr-AC ~ CRGT had no direct effect on the kinase activity of c-Src in living cells as evidenced by its inability to dissociate Csk from c-Src or to alter the phosphorylation level of c-Src Y416 and Y527, consistent results were also from in vitro kinase assays. Under flow conditions, the myr-AC ~ CRGT peptide caused an inhibition of platelet thrombus formation predominantly at high shear rates. Conclusions These findings provide novel insights into the molecular mechanisms by which the RGT peptide regulates integrin signaling and platelet function and reinforce the potential of the RGT peptide-induced disruption of Src/β3 association as a druggable target that would finally enable in vivo and clinical studies using the structure-based small molecular mimetics. Electronic supplementary material The online version of this article (doi:10.1186/s13045-015-0159-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jiansong Huang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
| | - Xiaofeng Shi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
| | - Wenda Xi
- Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
| | - Ping Liu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
| | - Zhangbiao Long
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
| | - Xiaodong Xi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China. .,Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Second Ruijin Road, Shanghai, 200025, China.
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Merkle VM, Martin D, Hutchinson M, Tran PL, Behrens A, Hossainy S, Bluestein D, Wu X, Slepian MJ. Hemocompatibility of Poly(vinyl alcohol)-Gelatin Core-Shell Electrospun Nanofibers: A Scaffold for Modulating Platelet Deposition and Activation. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8302-12. [PMID: 25815434 PMCID: PMC4545287 DOI: 10.1021/acsami.5b01671] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this study, we evaluate coaxial electrospun nanofibers with gelatin in the shell and poly(vinyl alcohol) (PVA) in the core as a potential vascular material by determining fiber surface roughness, as well as human platelet deposition and activation under varying conditions. PVA scaffolds had the highest surface roughness (Ra=65.5±6.8 nm) but the lowest platelet deposition (34.2±5.8 platelets) in comparison to gelatin nanofibers (Ra=36.8±3.0 nm and 168.9±29.8 platelets) and coaxial nanofibers (1 Gel:1 PVA coaxial, Ra=24.0±1.5 nm and 150.2±17.4 platelets. 3 Gel:1 PVA coaxial, Ra=37.1±2.8 nm and 167.8±15.4 platelets). Therefore, the chemical structure of the gelatin nanofibers dominated surface roughness in platelet deposition. Due to their increased stiffness, the coaxial nanofibers had the highest platelet activation rate, rate of thrombin formation, in comparison to gelatin and PVA fibers. Our studies indicate that mechanical stiffness is a dominating factor for platelet deposition and activation, followed by biochemical signals, and lastly surface roughness. Overall, these coaxial nanofibers are an appealing material for vascular applications by supporting cellular growth while minimizing platelet deposition and activation.
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Affiliation(s)
- Valerie M. Merkle
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
| | - Daniel Martin
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
| | - Marcus Hutchinson
- Department of Molecular and Cellular Biology, The University of Arizona, Tucson, Arizona U.S.A
| | - Phat L. Tran
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
| | - Alana Behrens
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
| | - Samir Hossainy
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
| | - Danny Bluestein
- Aerospace & Mechanical Engineering Department, The University of Arizona, Tucson, Arizona, U.S.A
| | - Xiaoyi Wu
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
- Corresponding author at: Aerospace and Mechanical Engineering Department, The University of Arizona, Tucson AZ 85721, USA. Tel.: 1-520-626-5854 Fax: 1-00-520-621-8191,
| | - Marvin J. Slepian
- Biomedical Engineering Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona U.S.A
- Department of Biomedical Engineering, The University of Arizona, Tucson, Arizona U.S.A
- Sarver Heart Center, Department of Medicine, The University of Arizona, Tucson, Arizona, U.S.A
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York U.S.A
- Corresponding author at: Sarver Heart Center, College of Medicine, The University of Arizona, Tucson AZ 85721, USA. Tel.: +1 520 626 8543,
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Platelet dysfunction and platelet transfusion in traumatic brain injury. J Surg Res 2015; 193:802-6. [DOI: 10.1016/j.jss.2014.08.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 04/10/2014] [Accepted: 08/08/2014] [Indexed: 11/22/2022]
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Scott R, Panitch A. Macromolecular approaches to prevent thrombosis and intimal hyperplasia following percutaneous coronary intervention. Biomacromolecules 2014; 15:2825-32. [PMID: 24964369 PMCID: PMC4130236 DOI: 10.1021/bm5007757] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 06/18/2014] [Indexed: 01/29/2023]
Abstract
Cardiovascular disease remains one of the largest contributors to death worldwide. Improvements in cardiovascular technology leading to the current generation of drug-eluting stents, bioresorbable stents, and drug-eluting balloons, coupled with advances in antirestenotic therapeutics developed by pharmaceutical community, have had a profound impact on quality of life and longevity. However, these procedures and devices contribute to both short- and long-term complications. Thus, room for improvement and development of new, alternative strategies exists. Two major approaches have been investigated to improve outcomes following percutaneous coronary intervention including perivascular delivery and luminal paving. For both approaches, polymers play a major role as controlled research vehicles, carriers for cells, and antithrombotic coatings. With improvements in catheter delivery devices and increases in our understanding of the biology of healthy and diseased vessels, the time is ripe for development of novel macromolecular coatings that can protect the vessel lumen following balloon angioplasty and promote healthy vascular healing.
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Affiliation(s)
- Rebecca
A. Scott
- Weldon
School of Biomedical
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Alyssa Panitch
- Weldon
School of Biomedical
Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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Rönnlund D, Xu L, Perols A, Gad AKB, Eriksson Karlström A, Auer G, Widengren J. Multicolor fluorescence nanoscopy by photobleaching: concept, verification, and its application to resolve selective storage of proteins in platelets. ACS NANO 2014; 8:4358-4365. [PMID: 24730587 DOI: 10.1021/nn406113m] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fluorescence nanoscopy provides means to discern the finer details of protein localization and interaction in cells by offering an order of magnitude higher resolution than conventional optical imaging techniques. However, these super resolution techniques put higher demands on the optical system and the fluorescent probes, making multicolor fluorescence nanoscopy a challenging task. Here we present a new and simple procedure, which exploits the photostability and excitation spectra of dyes to increase the number of simultaneous recordable targets in STED nanoscopy. We use this procedure to demonstrate four-color STED imaging of platelets with ≤40 nm resolution and low crosstalk. Platelets can selectively store, sequester, and release a multitude of different proteins, in a manner specific for different physiological and disease states. By applying multicolor nanoscopy to study platelets, we can achieve spatial mapping of the protein organization with a high resolution for multiple proteins at the same time and in the same cell. This provides a means to identify specific platelet activation states for diagnostic purposes and to understand the underlying protein storage and release mechanisms. We studied the organization of the pro- and antiangiogenic proteins VEGF and PF-4, together with fibrinogen and filamentous actin, and found distinct features in their respective protein localization. Further, colocalization analysis revealed only minor overlap between the proteins VEGF and PF-4 indicating that they have separate storage and release mechanisms, corresponding well with their opposite roles as pro- and antiangiogenic proteins, respectively.
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Affiliation(s)
- Daniel Rönnlund
- Department of Applied Physics, Royal Institute of Technology , Stockholm, 106 91 Sweden
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Scott RA, Paderi JE, Sturek M, Panitch A. Decorin mimic inhibits vascular smooth muscle proliferation and migration. PLoS One 2013; 8:e82456. [PMID: 24278482 PMCID: PMC3838406 DOI: 10.1371/journal.pone.0082456] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/04/2013] [Indexed: 01/06/2023] Open
Abstract
Over the past 10 years, the number of percutaneous coronary intervention procedures performed in the United States increased by 33%; however, restenosis, which inhibits complete functional recovery of the vessel wall, complicates this procedure. A wide range of anti-restenotic therapeutics have been developed, although many elicit non-specific effects that compromise vessel healing. Drawing inspiration from biologically-relevant molecules, our lab developed a mimic of the natural proteoglycan decorin, termed DS-SILY, which can mask exposed collagen and thereby effectively decrease platelet activation, thus contributing to suppression of vascular intimal hyperplasia. Here, we characterize the effects of DS-SILY on both proliferative and quiescent human SMCs to evaluate the potential impact of DS-SILY-SMC interaction on restenosis, and further characterize in vivo platelet interactions. DS-SILY decreased proliferative SMC proliferation and pro-inflammatory cytokine secretion in vitro in a concentration dependent manner as compared to untreated controls. The addition of DS-SILY to in vitro SMC cultures decreased SMC migration and protein synthesis by 95% and 37%, respectively. Furthermore, DS-SILY decreased platelet activation, as well as reduced neointimal hyperplasia by 60%, in vivo using Ossabaw swine. These results indicate that DS-SILY demonstrates multiple biological activities that may all synergistically contribute to an improved treatment paradigm for balloon angioplasty.
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Affiliation(s)
- Rebecca A. Scott
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - John E. Paderi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
| | - Michael Sturek
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Alyssa Panitch
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States of America
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Bijak M, Saluk J, Tsirigotis-Maniecka M, Komorowska H, Wachowicz B, Zaczyńska E, Czarny A, Czechowski F, Nowak P, Pawlaczyk I. The influence of conjugates isolated from Matricaria chamomilla L. on platelets activity and cytotoxicity. Int J Biol Macromol 2013; 61:218-29. [PMID: 23831537 DOI: 10.1016/j.ijbiomac.2013.06.046] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 06/16/2013] [Accepted: 06/26/2013] [Indexed: 01/23/2023]
Abstract
Cardiovascular diseases (CVD) remain the principal cause of death in both advanced and developing countries of the world. Blood platelets are involved in the pathogenesis of atherosclerosis and thrombosis. Platelet adhesion and aggregation are critical events that occur in unstable coronary syndromes. The current research is focused on the role of polysaccharide-polyphenolic conjugates isolated from chamomile (Matricaria chamomilla L.) at concentrations of 10, 25, 50 and 100 μg/mL on blood platelets (obtained from healthy donors and from patients received combined anti-platelet therapy complex with clopidogrel and acetylsalicylic acid) aggregation and experimentally induced cell toxicity. The treatment of PRP obtained from healthy donors with polyphenolic-polysaccharide conjugates from M. chamomilla (L.) (MC) resulted in a dose-dependent, decrease of platelet aggregation induced by multiple agonists (ADP, collagen and arachidonic acid). In this study we also observed that the MC reduced platelet aggregation in PRP obtained from patients with cardiovascular disorders. The result of testing the MC on human blood platelets, mouse fibroblast cultures L929 and human lung cells A549 did not show any cytotoxicity effects. Compounds obtained from M. chamomilla L. are potential composite to the development of a new anti-platelet agent, which could be an alternative to the currently used anti-platelet drugs.
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Affiliation(s)
- Michał Bijak
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; Regional Specialist Hospital in Wroclaw, Research and Development Centre, H.M. Kamieńskiego 73a, 51-124 Wroclaw, Poland.
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Scott RA, Park K, Panitch A. Water soluble polymer films for intravascular drug delivery of antithrombotic biomolecules. Eur J Pharm Biopharm 2013; 84:125-31. [PMID: 23262161 PMCID: PMC3619018 DOI: 10.1016/j.ejpb.2012.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/02/2012] [Accepted: 12/05/2012] [Indexed: 02/02/2023]
Abstract
Over the past 10 years, the number of percutaneous coronary intervention (PCI) procedures performed in the United States has increased by 33%; however, restenosis, which inhibits complete functional recovery of the vessel wall, remains a complication of this procedure. To traverse the complications associated with PCI, the investigation of therapeutic delivery has become an integral topic in modern research. One such therapeutic, a mimic of the proteoglycan decorin, termed DS-SILY, can mask exposed collagen and thereby effectively decrease platelet activation, has recently been developed by our lab. Drawing inspiration from coating technologies developed by the pharmaceutical industry, a fast-dissolving polymer film has been developed to deliver active therapeutic agents from a balloon catheter during PCI. This research investigates the release of DS-SILY from fast-dissolving polymer films composed of poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG). Thin, uniform polymer films were produced via spin coating technique. The dissolution speed of the polymer films was found to be dependent on the concentration of polymer solution, where at least 65% of the films were shown to dissolve into nanometer sized polymer fragments within 2 min. DS-SILY, up to 6.26 μg/cm(2), was loaded into the films and functional release of the mimic was demonstrated by its successful binding to collagen upon release. Furthermore, DS-SILY released from films resulted in increased platelet inhibition. These results indicate that use of fast-dissolving polymer films allow for the successful release of biomolecules and further investigation of their use for localized drug delivery during PCI procedures is warranted.
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Affiliation(s)
- Rebecca A. Scott
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Kinam Park
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
- School of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47907
| | - Alyssa Panitch
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
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Modery-Pawlowski CL, Tian LL, Ravikumar M, Wong TL, Gupta AS. In vitro and in vivo hemostatic capabilities of a functionally integrated platelet-mimetic liposomal nanoconstruct. Biomaterials 2013; 34:3031-41. [DOI: 10.1016/j.biomaterials.2012.12.045] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/22/2012] [Indexed: 10/27/2022]
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Attwood SJ, Simpson AMC, Hamaia S, Bihan D, Roy D, Farndale R, Welland ME. Measurement of the Interaction Between Recombinant I-domain from Integrin alpha 2 beta 1 and a Triple Helical Collagen Peptide with the GFOGER Binding Motif Using Molecular Force Spectroscopy. Int J Mol Sci 2013; 14:2832-45. [PMID: 23434650 PMCID: PMC3588017 DOI: 10.3390/ijms14022832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/08/2013] [Accepted: 01/21/2013] [Indexed: 11/17/2022] Open
Abstract
The role of the collagen-platelet interaction is of crucial importance to the haemostatic response during both injury and pathogenesis of the blood vessel wall. Of particular interest is the high affinity interaction of the platelet transmembrane receptor, alpha 2 beta 1, responsible for firm attachment of platelets to collagen at and around injury sites. We employ single molecule force spectroscopy (SMFS) using the atomic force microscope (AFM) to study the interaction of the I-domain from integrin alpha 2 beta 1 with a synthetic collagen related triple-helical peptide containing the high-affinity integrin-binding GFOGER motif, and a control peptide lacking this sequence, referred to as GPP. By utilising synthetic peptides in this manner we are able to study at the molecular level subtleties that would otherwise be lost when considering cell-to-collagen matrix interactions using ensemble techniques. We demonstrate for the first time the complexity of this interaction as illustrated by the complex multi-peaked force spectra and confirm specificity using control blocking experiments. In addition we observe specific interaction of the GPP peptide sequence with the I-domain. We propose a model to explain these observations.
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Affiliation(s)
- Simon J. Attwood
- Nanoscience Centre, Department of Engineering, Cambridge University, Cambridge, CB3 0FF, UK; E-Mail:
| | - Anna M. C. Simpson
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, UK; E-Mails: (A.M.C.S.); (S.W.H.); (D.B.)
| | - SamirW. Hamaia
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, UK; E-Mails: (A.M.C.S.); (S.W.H.); (D.B.)
| | - Dominique Bihan
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, UK; E-Mails: (A.M.C.S.); (S.W.H.); (D.B.)
| | - Debdulal Roy
- National Physical Laboratory, Teddington, TW11 0LW, UK; E-Mail:
| | - RichardW. Farndale
- Department of Biochemistry, Cambridge University, Cambridge, CB2 1QW, UK; E-Mails: (A.M.C.S.); (S.W.H.); (D.B.)
- Authors to whom correspondence should be addressed; E-Mails: (R.W.F.); (M.E.W.); Tel.: +44-1223-766111 (R.W.F.); +44-1223-760305 (M.E.W.); Fax: +44 -1223-760309 (M.E.W.)
| | - Mark E. Welland
- Nanoscience Centre, Department of Engineering, Cambridge University, Cambridge, CB3 0FF, UK; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (R.W.F.); (M.E.W.); Tel.: +44-1223-766111 (R.W.F.); +44-1223-760305 (M.E.W.); Fax: +44 -1223-760309 (M.E.W.)
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Ravikumar M, Modery CL, Wong TL, Dzuricky M, Sen Gupta A. Mimicking adhesive functionalities of blood platelets using ligand-decorated liposomes. Bioconjug Chem 2012; 23:1266-75. [PMID: 22607514 DOI: 10.1021/bc300086d] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Platelet transfusion is used for treating a variety of bleeding complications. Natural platelet-based transfusion products have very short storage life (3-7 days) and high risks of biological contamination and side effects. Consequently, there is significant clinical interest in synthetic platelet-mimetic constructs that can promote hemostasis, while allowing convenient large-scale production, easy portability, long storage life, and minimal biological risks. To this end, research efforts are being directed toward particles that can amplify aggregation of activated platelets or can mimic platelet's ability to undergo adhesion to various vascular matrix proteins. Here, we report on a synthetic construct design that combines the mimicry of platelet's shear-dependent adhesion to vWF and shear-independent adhesion to collagen under flow, on a single particle. For this, we have used 150-nm-diameter liposomes as model particles and have decorated their surface simultaneously with vWF-binding and collagen-binding recombinant protein fragments or synthetic peptide motifs. We demonstrate in vitro that these surface-modified liposomes are able to adhere onto vWF surfaces in a shear-dependent fashion and onto collagen surfaces in a shear-independent fashion under flow. Moreover, when the vWF-binding and the collagen-binding were integrated on a single liposomal platform, the resultant heteromultivalent liposomes showed significantly enhanced adhesion to a vWF/collagen mixed surface compared to liposomes bearing vWF-binding or collagen-binding ligands only, as long as the ligand motifs did not spatially interfere with each other. Altogether, our results establish the feasibility of efficiently mimicking platelet's dual adhesion mechanisms on synthetic particles.
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Affiliation(s)
- Madhumitha Ravikumar
- Department of Biomedical Engineering, Case Western Reserve University , Cleveland, Ohio 44106, United States
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Corum LE, Hlady V. The effect of upstream platelet-fibrinogen interactions on downstream adhesion and activation. Biomaterials 2011; 33:1255-60. [PMID: 22100981 DOI: 10.1016/j.biomaterials.2011.10.074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 10/27/2011] [Indexed: 12/15/2022]
Abstract
Circulating activated platelets roll and make transient contacts before ultimately adhering to a substrate. However, despite the dynamic nature of platelet adhesion, most in vitro adhesion and activation studies have focused on establishing local cause and effect relationships. Here, we determined the effect of exposing platelets to immobilized upstream human fibrinogen on downstream adhesion and activation. Microcontact printing was used to prepare substrates that contained well defined fibrinogen priming regions. Washed platelets were perfused over the substrates and adhesion and activation in a downstream capture region were compared with samples that did not contain a fibrinogen priming region. It was found that samples containing an upstream priming region resulted in higher adhesion, platelet spreading areas and aggregation than samples that lacked the priming region. Also, when the priming region was selectively blocked with a polyclonal anti-fibrinogen antibody, the platelet response was attenuated. To characterize this phenomenon further, flow cytometry was used to assess bulk platelet activation following fibrinogen priming. The expression of two activation markers, PAC-1 and P-selectin were quantified. Expression of both activation markers was found to be higher after perfusion over fibrinogen versus albumin-coated substrates.
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Affiliation(s)
- Lindsey E Corum
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
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Hansen RR, Tipnis AA, White-Adams TC, Di Paola JA, Neeves KB. Characterization of collagen thin films for von Willebrand factor binding and platelet adhesion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13648-58. [PMID: 21967679 PMCID: PMC9028814 DOI: 10.1021/la2023727] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Von Willebrand factor (VWF) binding and platelet adhesion to subendothelial collagens are initial events in thrombus formation at sites of vascular injury. These events are often studied in vitro using flow assays designed to mimic vascular hemodynamics. Flow assays commonly employ collagen-functionalized substrates, but a lack of standardized methods of surface ligation limits their widespread use as a clinical diagnostic. Here, we report the use of collagen thin films (CTF) in flow assays. Thin films were grown on hydrophobic substrates from type I collagen solutions of increasing concentration (10, 100, and 1000 μg/mL). We found that the corresponding increase in fiber surface area determined the amount of VWF binding and platelet adhesion. The association rate constant (k(a)) of plasma VWF binding at a wall shear stress of 45 dyn/cm(2) was 0.3 × 10(5), 1.8 × 10(5), and 1.6 × 10(5) M(-1) s(-1) for CTF grown from 10, 100, and 1000 μg/mL solutions, respectively. We observed a 5-fold increase in VWF binding capacity with each 10-fold increase in collagen solution concentration. The association rates of Ser1731Thr and His1786Asp VWF mutants with collagen binding deficiencies were 9% and 22%, respectively, of wild-type rates. Using microfluidic devices for blood flow assays, we observed that CTF supported platelet adhesion at a wall shear rate of 1000 s(-1). CTF grown from 10 and 100 μg/mL solutions had variable levels of platelet surface coverage between multiple normal donors. However, CTF substrates grown from 1000 μg/mL solutions had reproducible surface coverage levels (74 ± 17%) between normal donors, and there was significantly diminished surface coverage from two type 1 von Willebrand disease patients (8.0% and 24%). These results demonstrate that collagen thin films are homogeneous and reproducible substrates that can measure dysfunctions in VWF binding and platelet adhesion under flow in a clinical microfluidic assay format.
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Affiliation(s)
- Ryan R. Hansen
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Alena A. Tipnis
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Tara C. White-Adams
- Department of Pediatrics, University of Colorado, Aurora, Colorado 80045, United States
| | - Jorge A. Di Paola
- Department of Pediatrics, University of Colorado, Aurora, Colorado 80045, United States
| | - Keith B. Neeves
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- Department of Pediatrics, University of Colorado, Aurora, Colorado 80045, United States
- Corresponding Author: , Tel: 01-303-273-3191, Fax: 01-303-273-3730
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Mendelboum Raviv S, Szekeres-Csiki K, Jenei A, Nagy J, Shenkman B, Savion N, Harsfalvi J. Coating conditions matter to collagen matrix formation regarding von Willebrand factor and platelet binding. Thromb Res 2011; 129:e29-35. [PMID: 22056526 DOI: 10.1016/j.thromres.2011.09.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 08/30/2011] [Accepted: 09/25/2011] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Von Willebrand factor (VWF) and platelet binding needs a uniform collagen matrix therefore we aimed to find an optimal condition for the preparation of human type-I and type-III collagen matrices. METHOD The effects of pH, salt and ligand concentration and binding time were tested when collagen matrices were prepared by adsorption. Surface-bound collagen and collagen-bound VWF measured by specific antibodies. Platelet adhesion was tested under flow conditions at a shear rate of 1800s(-1) for 2 min. Matrices and platelets were visualized by atomic force and scanning electron microscope. RESULTS The extent of human collagens type-I and III binding to the surface was 10 and 4 times greater and binding was maximal under 8-16 hours, when coated from physiological buffer solution versus acid solution. Collagen fibrils were more developed and platelet adhesion was higher, with more organized and denser aggregates. VWF binding was parallel to the surface bound collagen in both collagen types. CONCLUSION Collagen coating of surfaces for VWF binding and platelet adhesion studies is very variable from acid solution. Our experiments provide evidences that neutralizing the acid and adding NaCl in physiological concentration, thereby facilitating formation of collagen fibril molecules in solution, results in efficient coating of human type-I and type III collagens, which then bind normal VWF equally well.
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66
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Khan S, Jesacher A, Nussbaumer W, Bernet S, Ritsch-Marte M. Quantitative analysis of shape and volume changes in activated thrombocytes in real time by single-shot spatial light modulator-based differential interference contrast imaging. JOURNAL OF BIOPHOTONICS 2011; 4:600-9. [PMID: 21500360 DOI: 10.1002/jbio.201100010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/25/2011] [Accepted: 03/27/2011] [Indexed: 05/24/2023]
Abstract
We suggest to use a combination of optical tweezers and single-image quantitative differential interference contrast (DIC) emulated by a spatial light modulator (SLM) to study physiological shape changes in thrombocytes after activation and demonstrate the effectiveness of this system for the given task. A specially designed phase mask displayed at the SLM enables quantitative phase calculation from only a single recording. The optical tweezers stabilize trapped thrombocytes for long-time monitoring of changes in the optical thickness profile of thrombocytes during activation by adenosine diphosphate (ADP).
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Affiliation(s)
- Saranjam Khan
- Division for Biomedical Physics, Innsbruck Medical University, 6020 Innsbruck, Austria.
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67
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Sabrkhany S, Griffioen AW, Oude Egbrink MGA. The role of blood platelets in tumor angiogenesis. Biochim Biophys Acta Rev Cancer 2010; 1815:189-96. [PMID: 21167916 DOI: 10.1016/j.bbcan.2010.12.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 12/03/2010] [Accepted: 12/04/2010] [Indexed: 01/20/2023]
Abstract
Coagulation abnormalities occur frequently in cancer patients. It is becoming evident that blood platelets have an important function in this process. However, understanding of the underlying mechanisms is still very modest. In this review, we discuss the role of platelets in tumor angiogenesis and growth and suggest their potential significance in malignancies. Platelets contain various pro-and antiangiogenic molecules, which seem to be endocytosed and sequestered in different populations of α-granules. Furthermore, tumor endothelial cells are phenotypically and functionally different from endothelial cells in healthy tissue, stimulating local platelet adhesion and subsequent activation. As a consequence, platelets are able to secrete their angiogenic and angiostatic content, most likely in a regulated manner. The overall effect of these platelet-endothelium interactions appears to be proangiogenic, stimulating tumor angiogenesis. We favor the view that local adhesion and activation of blood platelets and dysregulation of coagulation represent underestimated pathways in the progression of cancer.
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Affiliation(s)
- Siamack Sabrkhany
- Laboratory for Microcirculation, Cardiovascular Research Institute Maastricht (CARIM), Dept. of Physiology, Maastricht, The Netherlands
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68
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Sigalov AB. The SCHOOL of nature: III. From mechanistic understanding to novel therapies. SELF/NONSELF 2010; 1:192-224. [PMID: 21487477 PMCID: PMC3047783 DOI: 10.4161/self.1.3.12794] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 11/19/2022]
Abstract
Protein-protein interactions play a central role in biological processes and thus represent an appealing target for innovative drug design and development. They can be targeted by small molecule inhibitors, modulatory peptides and peptidomimetics, which represent a superior alternative to protein therapeutics that carry many disadvantages. Considering that transmembrane signal transduction is an attractive process to therapeutically control multiple diseases, it is fundamentally and clinically important to mechanistically understand how signal transduction occurs. Uncovering specific protein-protein interactions critical for signal transduction, a general platform for receptor-mediated signaling, the signaling chain homooligomerization (SCHOOL) platform, suggests these interactions as universal therapeutic targets. Within the platform, the general principles of signaling are similar for a variety of functionally unrelated receptors. This suggests that global therapeutic strategies targeting key protein-protein interactions involved in receptor triggering and transmembrane signal transduction may be used to treat a diverse set of diseases. This also assumes that clinical knowledge and therapeutic strategies can be transferred between seemingly disparate disorders, such as T cell-mediated skin diseases and platelet disorders or combined to develop novel pharmacological approaches. Intriguingly, human viruses use the SCHOOL-like strategies to modulate and/or escape the host immune response. These viral mechanisms are highly optimized over the millennia, and the lessons learned from viral pathogenesis can be used practically for rational drug design. Proof of the SCHOOL concept in the development of novel therapies for atopic dermatitis, rheumatoid arthritis, cancer, platelet disorders and other multiple indications with unmet needs opens new horizons in therapeutics.
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69
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Sigalov AB. The SCHOOL of nature: I. Transmembrane signaling. SELF/NONSELF 2010; 1:4-39. [PMID: 21559175 PMCID: PMC3091606 DOI: 10.4161/self.1.1.10832] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 11/30/2009] [Accepted: 12/01/2009] [Indexed: 11/19/2022]
Abstract
Receptor-mediated transmembrane signaling plays an important role in health and disease. Recent significant advances in our understanding of the molecular mechanisms linking ligand binding to receptor activation revealed previously unrecognized striking similarities in the basic structural principles of function of numerous cell surface receptors. In this work, I demonstrate that the Signaling Chain Homooligomerization (SCHOOL)-based mechanism represents a general biological mechanism of transmembrane signal transduction mediated by a variety of functionally unrelated single- and multichain activating receptors. within the SCHOOL platform, ligand binding-induced receptor clustering is translated across the membrane into protein oligomerization in cytoplasmic milieu. This platform resolves a long-standing puzzle in transmembrane signal transduction and reveals the major driving forces coupling recognition and activation functions at the level of protein-protein interactions-biochemical processes that can be influenced and controlled. The basic principles of transmembrane signaling learned from the SCHOOL model can be used in different fields of immunology, virology, molecular and cell biology and others to describe, explain and predict various phenomena and processes mediated by a variety of functionally diverse and unrelated receptors. Beyond providing novel perspectives for fundamental research, the platform opens new avenues for drug discovery and development.
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Affiliation(s)
- Alexander B Sigalov
- Department of Pathology; University of Massachusetts Medical School; Worcester, MA USA
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70
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71
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Jain S, Russell S, Ware J. Platelet glycoprotein VI facilitates experimental lung metastasis in syngenic mouse models. J Thromb Haemost 2009; 7:1713-7. [PMID: 19624454 DOI: 10.1111/j.1538-7836.2009.03559.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Glycoprotein (GP)VI is a key receptor for collagen on the platelet surface. It is a member of the immunoglobulin superfamily and is uniquely expressed on the surface of platelets, where it is assembled with the immunoreceptor tyrosine activation motif subunit, FcR-gamma. We have previously reported the generation of a murine model of GPVI deficiency that revealed profound defects in collagen-induced platelet aggregation and in platelet activation following adhesion to collagen. Beyond the hemostasis/thrombosis paradigm, platelet receptors are emerging as significant participants in tumorigenesis and inflammation. OBJECTIVE In the current study, we have evaluated a role for platelet GPVI in primary tumor growth and experimental metastasis. METHODS Primary tumor induction and experimental metastasis assays were performed using syngenic immunocompetent animals and tumor cells derived from the C57BL/6J mouse strain in wild-type (C57BL/6J) and N10 C57BL/6J congenic GPVI-deficient mice. RESULTS Using either a Lewis lung carcinoma (D121) or melanoma (B16F10.1) cell line, we observed an approximately 50% reduction in the number of visible tumor foci in GPVI-deficient mice as compared with control C57BL/6J mice. Additional studies were performed to compare the size of subcutaneously implanted tumor cells, that is, primary tumor growth. Here, we observed no noticeable size difference when comparing the presence or absence of platelet GPVI. CONCLUSIONS The results demonstrate that the presence of platelet GPVI facilitates experimental tumor metastasis but does not contribute to the growth of primary tumors.
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MESH Headings
- Animals
- Bleeding Time
- Carcinoma, Lewis Lung/blood
- Carcinoma, Lewis Lung/blood supply
- Carcinoma, Lewis Lung/physiopathology
- Carcinoma, Lewis Lung/secondary
- Cell Line, Tumor/transplantation
- Crosses, Genetic
- Female
- Hemorrhagic Disorders/genetics
- Injections, Intravenous
- Lung Neoplasms/blood
- Lung Neoplasms/blood supply
- Lung Neoplasms/physiopathology
- Lung Neoplasms/secondary
- Male
- Melanoma, Experimental/blood
- Melanoma, Experimental/blood supply
- Melanoma, Experimental/physiopathology
- Melanoma, Experimental/secondary
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neoplasm Proteins/physiology
- Platelet Glycoprotein GPIb-IX Complex/physiology
- Platelet Membrane Glycoproteins/deficiency
- Platelet Membrane Glycoproteins/genetics
- Platelet Membrane Glycoproteins/physiology
- Tail
- Transplantation, Isogeneic
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Affiliation(s)
- S Jain
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA
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72
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Relative contributions of collagen and tissue factor to thrombus formation on damaged vascular vessels: in-vitro studies with circulating blood. Coron Artery Dis 2009; 20:392-9. [DOI: 10.1097/mca.0b013e32832cff1f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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73
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Fung CYE, Marcus AJ, Broekman MJ, Mahaut-Smith MP. P2X(1) receptor inhibition and soluble CD39 administration as novel approaches to widen the cardiovascular therapeutic window. Trends Cardiovasc Med 2009; 19:1-5. [PMID: 19467446 DOI: 10.1016/j.tcm.2009.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 01/26/2009] [Accepted: 01/30/2009] [Indexed: 11/16/2022]
Abstract
Thrombus formation at sites of disrupted atherosclerotic plaques is a leading cause of death and disability worldwide. Although the platelet is now recognized to be a central regulator of thrombus formation, development of antiplatelet reagents that selectively target thrombosis over hemostasis represents a challenge. Existing prophylactic antiplatelet therapies are centered on the use of aspirin, an irreversible cyclooxygenase inhibitor, and a thienopyridine such as clopidogrel, which inactivates the adenosine diphosphate-stimulated P2Y(12) receptor. Although these compounds are widely used and have beneficial effects for patients, their antithrombotic benefit is complicated by an elevated bleeding risk and substantial or partial "resistance." Moreover, combination therapy with these two drugs increases the hemorrhagic risk even further. This review explores the possibility of inhibiting the platelet-surface ionotropic P2X(1) receptor and/or elevating CD39/NTPDase1 activity as new therapeutic approaches to reduce overall platelet reactivity and recruitment of surrounding platelets at prothrombotic locations. Because both proteins affect platelet activation at an early stage in the events leading to thrombosis but are less crucial in hemostasis, they provide new strategies to widen the cardiovascular therapeutic window without compromising safety.
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Affiliation(s)
- C Y E Fung
- Department of Cell Physiology and Pharmacology, University of Leicester, LE19HN Leicester, United Kingdom
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74
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Abstract
The era of Genome-Wide Association Studies (GWAS) commenced in 2007 with the study of the Wellcome Trust Case Control Consortium (WTCCC) which for the first time ever showed that risk loci can be identified by scanning the complete genome for sequence variation in large numbers of cases of disease and healthy controls. We and others have expanded on this effort and successfully identified the first 11 risk loci for myocardial infarction (MI) and coronary artery disease (CAD). Studies on quantitative traits provide an alternative approach to identify MI/CAD risk loci. This review captures the early successes in the emerging field of disease genomics.
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Affiliation(s)
- W H Ouwehand
- Department of Haematology, University of Cambridge and NHS Blood and Transplant, Cambridge, UK.
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75
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Characterization of static adhesion of human platelets in plasma to protein surfaces in microplates. Blood Coagul Fibrinolysis 2009; 20:197-206. [DOI: 10.1097/mbc.0b013e328327353d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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76
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Markovic S, Milosevic M, Djordjevic N, Ognjanovic B, Stajn A, Saicic Z, Spasic M. Time course of hematological parameters in bleeding-induced anemia. ARCH BIOL SCI 2009. [DOI: 10.2298/abs0902165m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
In order to investigate daily changes of hematological parameters in bleeding-induced anemia, we treated Wistar albino male rats by daily bleeding (1.5-2 mL of blood from the tail vein for eight days). Blood samples were taken before (on day zero) and on the first to eighth days of bleeding. The values of hematocrit, hemoglobin, and erythrocyte count decreased significantly after the second, sixth, and second days of bleeding, respectively. The number of leuko?cytes and platelets, as well as Heinz body levels, increased significantly after the third and second days of treatment. The percentage of reticulocytes increased significantly from the second day and attained the maximum level (32.55 ? 0.96%) on the eighth day.
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Affiliation(s)
- Snezana Markovic
- Institut za biologiju i ekologiju, Prirodno-matematički fakultet, Kragujevac
| | - Marijana Milosevic
- Institut za biologiju i ekologiju, Prirodno-matematički fakultet, Kragujevac
| | - Natasa Djordjevic
- Institut za biologiju i ekologiju, Prirodno-matematički fakultet, Kragujevac
| | - Branka Ognjanovic
- Institut za biologiju i ekologiju, Prirodno-matematički fakultet, Kragujevac
| | - A.S. Stajn
- Institut za biologiju i ekologiju, Prirodno-matematički fakultet, Kragujevac
| | - Zorica Saicic
- Odeljenje za fiziologiju, Institut za biološka istraživanja 'Siniša Stanković', Beograd
| | - M.B. Spasic
- Odeljenje za fiziologiju, Institut za biološka istraživanja 'Siniša Stanković', Beograd
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77
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Signaling Chain Homooligomerization (SCHOOL) Model. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 640:121-63. [DOI: 10.1007/978-0-387-09789-3_12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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78
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79
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Abstract
Protein-protein interactions play a central role in biological processes and thus are an appealing target for innovative drug design a nd development. They can be targeted bysmall molecule inhibitors, peptides and peptidomimetics, which represent an alternative to protein therapeutics that carry many disadvantages. In this chapter, I describe specific protein-protein interactions suggested by a novel model of immune signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) model, to be critical for cell activation mediated by multichain immune recognition receptors (MIRRs) expressed on different cells of the hematopoietic system. Unraveling a long-standing mystery of MIRR triggering and transmembrane signaling, the SCHOOL model reveals the intrareceptor transmembrane interactions and interreceptor cytoplasmic homointeractions as universal therapeutic targets for a diverse variety of disorders mediated by immune cells. Further, assuming that the general principles underlying MIRR-mediated transmembrane signaling mechanisms are similar, the SCHOOL model can be applied to any particular receptor of the MIRR family. Thus, an important application of the SCHOOL model is that global therapeutic strategies targeting key protein-protein interactions involved in MIRR triggering and transmembrane signal transduction may be used to treat a diverse set of immune-mediated diseases. This assumes that clinical knowledge and therapeutic strategies can be transferred between seemingly disparate disorders, such as T-cell-mediated skin diseases and platelet disorders, or combined to develop novel pharmacological approaches. Intriguingly, the SCHOOL model unravels the molecular mechanisms underlying ability of different human viruses such as human immunodeficiency virus, cytomegalovirus and severe acute respiratory syndrome coronavirus to modulate and/or escape the host immune response. It also demonstrates how the lessons learned from viral pathogenesis can be used practically for rational drug design. Application of this model to platelet collagen receptor signaling has already led to the development of a novel concept of platelet inhibition and the invention of new platelet inhibitors, thus proving the suggested hypothesis and highlighting the importance and broad perspectives of the SCHOOL model in the development of new targeting strategies.
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80
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Surin WR, Barthwal MK, Dikshit M. Platelet collagen receptors, signaling and antagonism: Emerging approaches for the prevention of intravascular thrombosis. Thromb Res 2008; 122:786-803. [DOI: 10.1016/j.thromres.2007.10.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 10/17/2007] [Accepted: 10/21/2007] [Indexed: 02/02/2023]
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81
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82
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White TC, Berny MA, Robinson DK, Yin H, DeGrado WF, Hanson SR, McCarty OJT. The leech product saratin is a potent inhibitor of platelet integrin α2β1 and von Willebrand factor binding to collagen. FEBS J 2007; 274:1481-91. [PMID: 17489103 DOI: 10.1111/j.1742-4658.2007.05689.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Subendothelial collagen plays an important role, via both direct and indirect mechanisms, in the initiation of thrombus formation at sites of vascular injury. Collagen binds plasma von Willebrand factor, which mediates platelet recruitment to collagen under high shear. Subsequently, the direct binding of the platelet receptors glycoprotein VI and alpha2beta1 to collagen is critical for platelet activation and stable adhesion. Leeches, have evolved a number of inhibitors directed towards platelet-collagen interactions so as to prevent hemostasis in the host during hematophagy. In this article, we describe the molecular mechanisms underlying the ability of the leech product saratin to inhibit platelet binding to collagen. In the presence of inhibitors of ADP and thromboxane A2, both saratin and 6F1, a blocking alpha2beta1 mAb, abrogated platelet adhesion to fibrillar and soluble collagen. Additionally, saratin eliminated alpha2beta1-dependent platelet adhesion to soluble collagen in the presence of an Src kinase inhibitor. Moreover, saratin prevented platelet-rich plasma adhesion to fibrillar collagen, a process dependent upon both alpha2beta1 and von Willebrand factor binding to collagen. Furthermore, saratin specifically inhibited the binding of the alpha2 integrin subunit I domain to collagen, and prevented platelet adhesion to collagen under flow to the same extent as observed in the presence of a combination of mAbs to glycoprotein Ib and alpha2beta1. These results demonstrate that saratin interferes with integrin alpha2beta1 binding to collagen in addition to inhibiting von Willebrand factor-collagen binding, presumably by binding to an overlapping epitope on collagen. This has significant implications for the use of saratin as a tool to inhibit platelet-collagen interactions.
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Affiliation(s)
- Tara C White
- Department of Biomedical Engineering, Oregon Health & Science University, 13B-CHH, 3303 SW Bond Avenue, Portland, OR 97239, USA
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83
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Bix G, Iozzo RA, Woodall B, Burrows M, McQuillan A, Campbell S, Fields GB, Iozzo RV. Endorepellin, the C-terminal angiostatic module of perlecan, enhances collagen-platelet responses via the alpha2beta1-integrin receptor. Blood 2006; 109:3745-8. [PMID: 17197432 PMCID: PMC1874567 DOI: 10.1182/blood-2006-08-039925] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Endorepellin, a C-terminal fragment of the vascular basement membrane proteoglycan perlecan, inhibits angiogenesis via the alpha2beta1-integrin receptor. Because this integrin is also implicated in platelet-collagen responses and because endorepellin or its fragments are generated in response to injury and inflammation, we hypothesized that endorepellin could also affect platelet biology. We discovered that endorepellin supported alpha2beta1-dependent platelet adhesion, without appreciably activating or aggregating platelets. Notably, endorepellin enhanced collagen-evoked responses in platelets, in a src kinase-dependent fashion, and enhanced the collagen-inhibitory effect of an alpha2beta1-integrin function-blocking antibody. Collectively, these results suggest that endorepellin/alpha2beta1-integrin interaction and effects are specific and dependent on cell type, differ from those emanated by exposure to collagen, and may be due to cellular differences in alpha2beta1-integrin activation/ligand affinity state. These studies also suggest a heretofore unrecognized role for angiostatic basement membrane fragments in platelet biology.
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Affiliation(s)
- Gregory Bix
- Department of Pathology, Anatomy and Cell Biology, Kimmel Cancer Center, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
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Mälarstig A, Lindahl B, Wallentin L, Siegbahn A. Soluble CD40L Levels Are Regulated by the −3459 A>G Polymorphism and Predict Myocardial Infarction and the Efficacy of Antithrombotic Treatment in Non-ST Elevation Acute Coronary Syndrome. Arterioscler Thromb Vasc Biol 2006; 26:1667-73. [PMID: 16627810 DOI: 10.1161/01.atv.0000222908.78873.36] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives—
Current evidence suggests the CD40–CD40L pathway as a key process in the development, progression, and outcome of acute coronary syndrome (ACS). The aim was to investigate the prognostic importance of soluble (s) CD40L levels, single nucleotide polymorphisms (SNP) in the CD40LG gene, and the relation between sCD40L and SNPs in patients with acute coronary syndromes (ACS).
Methods and Results—
Samples were obtained on admission from 2359 patients with non-ST elevation ACS randomized to an early invasive versus a conservative and to placebo controlled long-term dalteparin treatment in the FRISC-II study. The −3459 A>G SNP was identified as a novel regulator of sCD40L levels (
P
=0.001). In the placebo-treated group, sCD40L levels above median were associated with a 2.5-fold increased risk of myocardial infarction (MI) (
P
≤0.001) but not with raised mortality. In the dalteparin treated group, sCD40L showed no association with MI (
P
=0.75). Consequently, dalteparin treatment was effective in reducing the risk of MI only in patients with sCD40L levels above median. A combined assessment of troponin-T and sCD40L complemented the prognostic information on risk of MI.
Conclusions—
We identified a SNP in the CD40LG gene as a novel regulator of sCD40L plasma concentrations. Soluble CD40L levels above median reflect a prothrombotic state, which can be managed with the use of intense anti-thrombotic treatments.
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Affiliation(s)
- Anders Mälarstig
- Department of Medical Sciences, Clinical Chemistry, Uppsala University, S-751 85 Uppsala, Sweden
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