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Sen S, Spasic A, Sinha A, Wang J, Bush M, Li J, Nešić D, Zhou Y, Angiulli G, Morgan P, Salas-Estrada L, Takagi J, Walz T, Coller BS, Filizola M. Structure-Based Discovery of a Novel Class of Small-Molecule Pure Antagonists of Integrin αVβ3. J Chem Inf Model 2022; 62:5607-5621. [PMID: 36279366 PMCID: PMC9767310 DOI: 10.1021/acs.jcim.2c00999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inhibitors of integrin αVβ3 have therapeutic promise for a variety of diseases. Most αVβ3-targeting small molecules patterned after the RGD motif are partial agonists because they induce a high-affinity, ligand-binding conformation and prime the receptor to bind the ligand without an activating stimulus, in part via a charge-charge interaction between their aspartic acid carboxyl group and the metal ion in the metal-ion-dependent adhesion site (MIDAS). Building upon our previous studies on the related integrin αIIbβ3, we searched for pure αVβ3 antagonists that lack this typical aspartic acid carboxyl group and instead engage through direct binding to one of the coordinating residues of the MIDAS metal ion, specifically β3 E220. By in silico screening of two large chemical libraries for compounds interacting with β3 E220, we indeed discovered a novel molecule that does not contain an acidic carboxyl group and does not induce the high-affinity, ligand-binding state of the receptor. Functional and structural characterization of a chemically optimized version of this compound led to the discovery of a novel small-molecule pure αVβ3 antagonist that (i) does not prime the receptor to bind the ligand and does not induce hybrid domain swing-out or receptor extension as judged by antibody binding and negative-stain electron microscopy, (ii) binds at the RGD-binding site as predicted by metadynamics rescoring of induced-fit docking poses and confirmed by a cryo-electron microscopy structure of the compound-bound integrin, and (iii) coordinates the MIDAS metal ion via a quinoline moiety instead of an acidic carboxyl group.
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Affiliation(s)
- Soumyo Sen
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
| | - Aleksandar Spasic
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
| | - Anjana Sinha
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, The Rockefeller University, 1230 York Avenue, P.O. Box 309, New York, New York10065, United States
| | - Jialing Wang
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, 1230 York Avenue, P.O. Box 219, New York, New York10065, United States
| | - Martin Bush
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, 1230 York Avenue, P.O. Box 219, New York, New York10065, United States
| | - Jihong Li
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, The Rockefeller University, 1230 York Avenue, P.O. Box 309, New York, New York10065, United States
| | - Dragana Nešić
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, The Rockefeller University, 1230 York Avenue, P.O. Box 309, New York, New York10065, United States
| | - Yuchen Zhou
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
| | - Gabriella Angiulli
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, 1230 York Avenue, P.O. Box 219, New York, New York10065, United States
| | - Paul Morgan
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
| | - Leslie Salas-Estrada
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka565-0871, Japan
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, 1230 York Avenue, P.O. Box 219, New York, New York10065, United States
| | - Barry S Coller
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, The Rockefeller University, 1230 York Avenue, P.O. Box 309, New York, New York10065, United States
| | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York10029, United States
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2
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Novelli EM, Moon CH, Pham TA, Perkins LA, Little-Ihrig L, Tavakoli S, Mason NS, Lang L, Chen X, Laymon CM, Gladwin MT, Anderson CJ. First report of 68Ga-PRGD2 PET/MRI molecular imaging of vaso-occlusion in a patient with sickle cell disease. BJR Case Rep 2020; 6:20200024. [PMID: 33299586 PMCID: PMC7709053 DOI: 10.1259/bjrcr.20200024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/29/2020] [Accepted: 05/19/2020] [Indexed: 11/17/2022] Open
Abstract
Increased vascular cell adhesion (hyperadhesion) to the endothelium is responsible for the hallmark acute pain episodes, or vaso-occlusive crises (VOC), of sickle cell disease. The integrin αvβ3 plays an important role in VOC since it mediates sickle red blood cell adhesion to the endothelium, a process that leads to ischemia and painful bone infarction. In the pilot study presented herein, we hypothesized that real-time imaging of hyperadhesion could quantify VOC severity and identify the most vulnerable anatomical sites. We also hypothesized that harnessing hyperadhesion as a proximate event in VOC would provide sensitive, objective evidence of VOC before pain has developed. Specifically, we tested whether positron emission tomography (PET) imaging of integrin αvβ3 using the PET tracer 68Ga-PRGD2 would successfully image hyperadhesion associated with VOC in a patient with sickle cell disease. We observed persistently higher tracer uptake in the femurs during VOC compared to baseline. In the vessel, after an initial and transient increase during VOC, blood pool activity was similar between baseline and VOC. These findings suggest that PET imaging of integrin αvβ3 may be a valuable strategy for imaging of VOC.
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Affiliation(s)
| | - Chan Hong Moon
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, Pennsylvania
| | | | - Lydia A Perkins
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Lynda Little-Ihrig
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | | | | | - Lixin Lang
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD
| | | | - Mark T Gladwin
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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3
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Hebbel RP, Belcher JD, Vercellotti GM. The multifaceted role of ischemia/reperfusion in sickle cell anemia. J Clin Invest 2020; 130:1062-1072. [PMID: 32118586 DOI: 10.1172/jci133639] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sickle cell anemia is a unique disease dominated by hemolytic anemia and vaso-occlusive events. The latter trigger a version of ischemia/reperfusion (I/R) pathobiology that is singular in its origin, cyclicity, complexity, instability, perpetuity, and breadth of clinical consequences. Specific clinical features are probably attributable to local I/R injury (e.g., stroke syndromes) or remote organ injury (e.g., acute chest syndrome) or the systematization of inflammation (e.g., multifocal arteriopathy). Indeed, by fashioning an underlying template of endothelial dysfunction and vulnerability, the robust inflammatory systematization no doubt contributes to all sickle pathology. In this Review, we highlight I/R-targeting therapeutics shown to improve microvascular blood flow in sickle transgenic mice undergoing I/R, and we suggest how such insights might be translated into human therapeutic strategies.
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4
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Li J, Fukase Y, Shang Y, Zou W, Muñoz-Félix JM, Buitrago L, van Agthoven J, Zhang Y, Hara R, Tanaka Y, Okamoto R, Yasui T, Nakahata T, Imaeda T, Aso K, Zhou Y, Locuson C, Nesic D, Duggan M, Takagi J, Vaughan RD, Walz T, Hodivala-Dilke K, Teitelbaum SL, Arnaout MA, Filizola M, Foley MA, Coller BS. Novel Pure αVβ3 Integrin Antagonists That Do Not Induce Receptor Extension, Prime the Receptor, or Enhance Angiogenesis at Low Concentrations. ACS Pharmacol Transl Sci 2019; 2:387-401. [PMID: 32259072 PMCID: PMC7088984 DOI: 10.1021/acsptsci.9b00041] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Indexed: 01/12/2023]
Abstract
The integrin αVβ3 receptor has been implicated in several important diseases, but no antagonists are approved for human therapy. One possible limitation of current small-molecule antagonists is their ability to induce a major conformational change in the receptor that induces it to adopt a high-affinity ligand-binding state. In response, we used structural inferences from a pure peptide antagonist to design the small-molecule pure antagonists TDI-4161 and TDI-3761. Both compounds inhibit αVβ3-mediated cell adhesion to αVβ3 ligands, but do not induce the conformational change as judged by antibody binding, electron microscopy, X-ray crystallography, and receptor priming studies. Both compounds demonstrated the favorable property of inhibiting bone resorption in vitro, supporting potential value in treating osteoporosis. Neither, however, had the unfavorable property of the αVβ3 antagonist cilengitide of paradoxically enhancing aortic sprout angiogenesis at concentrations below its IC50, which correlates with cilengitide's enhancement of tumor growth in vivo.
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Affiliation(s)
- Jihong Li
- Allen and
Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, United States
| | - Yoshiyuki Fukase
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Yi Shang
- Department
of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York 10029-6574, United States
| | - Wei Zou
- Washington
University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St. Louis, Missouri 63110, United States
| | - José M. Muñoz-Félix
- Adhesion
and Angiogenesis Laboratory, Centre for Tumour Biology, Barts Cancer Institute—a CR-UK Centre of Excellence,
Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, United Kingdom
| | - Lorena Buitrago
- Allen and
Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, United States
| | - Johannes van Agthoven
- Leukocyte
Biology and Inflammation and Structural Biology Programs, Division
of Nephrology, Massachusetts General Hospital
and Harvard Medical School, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Yixiao Zhang
- Laboratory
of Molecular Electron Microscopy, Rockefeller
University, 1230 York Avenue, New York, New York 10065, United
States
| | - Ryoma Hara
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Yuta Tanaka
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Rei Okamoto
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Takeshi Yasui
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Takashi Nakahata
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Toshihiro Imaeda
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Kazuyoshi Aso
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Yuchen Zhou
- Department
of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York 10029-6574, United States
| | - Charles Locuson
- Agios Pharmaceuticals, 88 Sidney Street, Cambridge, Massachusetts 02139-4169, United States
| | - Dragana Nesic
- Allen and
Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, United States
| | - Mark Duggan
- LifeSci
Consulting, LLC, 18243
SE Ridgeview Drive, Tequesta, Florida 33469, United
States
| | - Junichi Takagi
- Laboratory
of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Roger D. Vaughan
- Rockefeller
University Center for Clinical and Translational Science, Rockefeller University, 2130 York Avenue, New York, New York 10065, United States
| | - Thomas Walz
- Laboratory
of Molecular Electron Microscopy, Rockefeller
University, 1230 York Avenue, New York, New York 10065, United
States
| | - Kairbaan Hodivala-Dilke
- Adhesion
and Angiogenesis Laboratory, Centre for Tumour Biology, Barts Cancer Institute—a CR-UK Centre of Excellence,
Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, United Kingdom
| | - Steven L. Teitelbaum
- Washington
University School of Medicine, Campus Box 8118, 660 South Euclid Avenue, St. Louis, Missouri 63110, United States
| | - M. Amin Arnaout
- Leukocyte
Biology and Inflammation and Structural Biology Programs, Division
of Nephrology, Massachusetts General Hospital
and Harvard Medical School, 149 13th Street, Charlestown, Massachusetts 02129, United States
| | - Marta Filizola
- Department
of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1677, New York, New York 10029-6574, United States
| | - Michael A. Foley
- Tri-Institutional
Therapeutics Discovery Institute, 413 East 69 Street, New York, New York 10021, United
States
| | - Barry S. Coller
- Allen and
Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, 1230 York Avenue, New York, New York 10065, United States
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Kim M, Alapan Y, Adhikari A, Little JA, Gurkan UA. Hypoxia-enhanced adhesion of red blood cells in microscale flow. Microcirculation 2017; 24:10.1111/micc.12374. [PMID: 28387057 PMCID: PMC5679205 DOI: 10.1111/micc.12374] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 04/03/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVES The advancement of microfluidic technology has facilitated the simulation of physiological conditions of the microcirculation, such as oxygen tension, fluid flow, and shear stress in these devices. Here, we present a micro-gas exchanger integrated with microfluidics to study RBC adhesion under hypoxic flow conditions mimicking postcapillary venules. METHODS We simulated a range of physiological conditions and explored RBC adhesion to endothelial or subendothelial components (FN or LN). Blood samples were injected into microchannels at normoxic or hypoxic physiological flow conditions. Quantitative evaluation of RBC adhesion was performed on 35 subjects with homozygous SCD. RESULTS Significant heterogeneity in RBC adherence response to hypoxia was seen among SCD patients. RBCs from a HEA population showed a significantly greater increase in adhesion compared to RBCs from a HNA population, for both FN and LN. CONCLUSIONS The approach presented here enabled the control of oxygen tension in blood during microscale flow and the quantification of RBC adhesion in a cost-efficient and patient-specific manner. We identified a unique patient population in which RBCs showed enhanced adhesion in hypoxia in vitro. Clinical correlates suggest a more severe clinical phenotype in this subgroup.
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Affiliation(s)
- Myeongseop Kim
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Yunus Alapan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Anima Adhikari
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Jane A. Little
- Department of Hematology and Oncology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Seidman Cancer Center at University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Umut A. Gurkan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Department of Hematology and Oncology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Department of Orthopaedics, Case Western Reserve University, Cleveland, OH, USA
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6
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Alapan Y, Fraiwan A, Kucukal E, Hasan MN, Ung R, Kim M, Odame I, Little JA, Gurkan UA. Emerging point-of-care technologies for sickle cell disease screening and monitoring. Expert Rev Med Devices 2016; 13:1073-1093. [PMID: 27785945 PMCID: PMC5166583 DOI: 10.1080/17434440.2016.1254038] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Sickle Cell Disease (SCD) affects 100,000 Americans and more than 14 million people globally, mostly in economically disadvantaged populations, and requires early diagnosis after birth and constant monitoring throughout the life-span of the patient. Areas covered: Early diagnosis of SCD still remains a challenge in preventing childhood mortality in the developing world due to requirements of skilled personnel and high-cost of currently available modalities. On the other hand, SCD monitoring presents insurmountable challenges due to heterogeneities among patient populations, as well as in the same individual longitudinally. Here, we describe emerging point-of-care micro/nano platform technologies for SCD screening and monitoring, and critically discuss current state of the art, potential challenges associated with these technologies, and future directions. Expert commentary: Recently developed microtechnologies offer simple, rapid, and affordable screening of SCD and have the potential to facilitate universal screening in resource-limited settings and developing countries. On the other hand, monitoring of SCD is more complicated compared to diagnosis and requires comprehensive validation of efficacy. Early use of novel microdevices for patient monitoring might come in especially handy in new clinical trial designs of emerging therapies.
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Affiliation(s)
- Yunus Alapan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Arwa Fraiwan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Erdem Kucukal
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - M. Noman Hasan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Ryan Ung
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Myeongseop Kim
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
| | - Isaac Odame
- Division of Haematology/Oncology, The Hospital for Sick Children; Toronto, Canada
- Department of Pediatrics, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Jane A. Little
- Department of Hematology and Oncology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Seidman Cancer Center at University Hospitals, Case Medical Center, Cleveland, OH, USA
| | - Umut A. Gurkan
- Case Biomanufacturing and Microfabrication Laboratory, Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Department of Orthopedics, Case Western Reserve University, Cleveland, OH, USA
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7
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Kalai M, Dridi M, Chaouch L, Moumni I, Ouragini H, Darragi I, Boudrigua I, Chaouachi D, Mellouli F, Bejaoui M, Abbes S. The role of rs1984112_G at CD36 gene in increasing reticulocyte level among sickle cell disease patients. ACTA ACUST UNITED AC 2016; 22:178-182. [PMID: 27869039 DOI: 10.1080/10245332.2016.1253253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AIMS AND BACKGROUND Mediators of adhesion become a potential new target for pharmacological therapy to struggle the complications of sickle cell disease (SCD). Several mechanisms for increased adherence have been postulated and the well-studied are CD36 and VLA4 which encoded by ITGA4. Herein, we sought to determine whether one polymorphism of CD36 namely: rs1984112 and three exons of ITGA4 (4, 5, and 6) are implicated in hemolytic status and clinical events among SCD Tunisian patients. MATERIAL AND METHODS This study enrolled 99 unrelated Tunisian subjects (63SS and 36Sβ). All SCD patients are children (less than 16 years old). The rs1984112 and the ITGA4's exons 4, 5, and 6 were analyzed for all subjects by PCR/sequencing. The association of each genotype found with both clinical complications and hemolytic status was performed using t-test. Clinical events studied included vaso-occlusive crisis (VOC), osteonecrosis, stroke, frequent infection, priapism, and acute syndrome. RESULTS The results show that rs1984112_G allele at CD36 gene revealed to be associated with higher levels of reticulocyte count (p < 0.01). The statistical result show a near significance of homozygous mutant GG genotype with VOC (p = 0.051). No association between rs1984112_G allele and the clinical severity of SCD were found. Mutational screening of exon 4, 5, and 6 of ITGA4 gene revealed absence of mutated variant. CONCLUSION Our results are similar to those found in Portuguese population which reported the role of rs1984112_G in increasing reticulocyte level among SCD patients. Consequently, the rs1984112_G of CD36 could be considered as a reliable biomarker for predicting patients at high risk for vascular occlusions and thus, allows earlier and more effective therapeutic management.
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Affiliation(s)
- Miniar Kalai
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Marwa Dridi
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Leila Chaouch
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Imen Moumni
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Houyem Ouragini
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Imen Darragi
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Imen Boudrigua
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Dorra Chaouachi
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Fethi Mellouli
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Mohamed Bejaoui
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
| | - Salem Abbes
- a Université de Tunis El Manar, Institut Pasteur de Tunis , Laboratoire d'Hématologie Moléculaire et Cellulaire , Tunis , Tunisia
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8
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Telen MJ, Batchvarova M, Shan S, Bovee-Geurts PH, Zennadi R, Leitgeb A, Brock R, Lindgren M. Sevuparin binds to multiple adhesive ligands and reduces sickle red blood cell-induced vaso-occlusion. Br J Haematol 2016; 175:935-948. [PMID: 27549988 DOI: 10.1111/bjh.14303] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/27/2016] [Indexed: 12/19/2022]
Abstract
Sevuparin is a novel drug candidate in phase II development as a treatment for vaso-occlusive crises (VOC) in patients with sickle cell disease (SCD). As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Here, we demonstrate that sevuparin inhibits the adhesion of human sickle red blood cells (SS-RBCs) to stimulated cultured endothelial cells in vitro. Importantly, sevuparin prevents vaso-occlusion and normalizes blood flow in an in vivo mouse model of SCD vaso-occlusion. Analyses by surface plasmon resonance (SPR) and fluorescence correlation spectroscopy (FCS) demonstrate that sevuparin binds to P- and L-selectins, thrombospondin, fibronectin and von Willebrand factor, all of which are thought to contribute to vaso-occlusion in SCD. Despite low anticoagulation activity, sevuparin has anti-adhesive efficacy similar to the low molecular weight heparin tinzaparin both in vitro and in vivo. These results suggest that the anti-adhesive properties rather than the anticoagulant effects of heparinoids are critical for the treatment of vaso-occlusion in SCD. Therefore, sevuparin is now being evaluated in SCD patients hospitalized for treatment of VOC.
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Affiliation(s)
- Marilyn J Telen
- Division of Hematology, Department of Medicine, Duke Comprehensive Sickle Cell Center, Duke University School of Medicine, Durham, NC, USA
| | - Milena Batchvarova
- Division of Hematology, Department of Medicine, Duke Comprehensive Sickle Cell Center, Duke University School of Medicine, Durham, NC, USA
| | - Siqing Shan
- Division of Hematology, Department of Medicine, Duke Comprehensive Sickle Cell Center, Duke University School of Medicine, Durham, NC, USA
| | - Petra H Bovee-Geurts
- Department of Biochemistry, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rahima Zennadi
- Division of Hematology, Department of Medicine, Duke Comprehensive Sickle Cell Center, Duke University School of Medicine, Durham, NC, USA
| | | | - Roland Brock
- Department of Biochemistry, Radboud University Medical Center, Nijmegen, The Netherlands
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9
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Sickle cell disease biochip: a functional red blood cell adhesion assay for monitoring sickle cell disease. Transl Res 2016; 173:74-91.e8. [PMID: 27063958 PMCID: PMC4959913 DOI: 10.1016/j.trsl.2016.03.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 03/08/2016] [Accepted: 03/12/2016] [Indexed: 01/10/2023]
Abstract
Sickle cell disease (SCD) afflicts millions of people worldwide and is associated with considerable morbidity and mortality. Chronic and acute vaso-occlusion are the clinical hallmarks of SCD and can result in pain crisis, widespread organ damage, and early movtality. Even though the molecular underpinnings of SCD were identified more than 60 years ago, there are no molecular or biophysical markers of disease severity that are feasibly measured in the clinic. Abnormal cellular adhesion to vascular endothelium is at the root of vaso-occlusion. However, cellular adhesion is not currently evaluated clinically. Here, we present a clinically applicable microfluidic device (SCD biochip) that allows serial quantitative evaluation of red blood cell (RBC) adhesion to endothelium-associated protein-immobilized microchannels, in a closed and preprocessing-free system. With the SCD biochip, we have analyzed blood samples from more than 100 subjects and have shown associations between the measured RBC adhesion to endothelium-associated proteins (fibronectin and laminin) and individual RBC characteristics, including hemoglobin content, fetal hemoglobin concentration, plasma lactate dehydrogenase level, and reticulocyte count. The SCD biochip is a functional adhesion assay, reflecting quantitative evaluation of RBC adhesion, which could be used at baseline, during crises, relative to various long-term complications, and before and after therapeutic interventions.
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Therapeutic approaches to limit hemolysis-driven endothelial dysfunction: scavenging free heme to preserve vasculature homeostasis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:396527. [PMID: 23781294 PMCID: PMC3678425 DOI: 10.1155/2013/396527] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/29/2013] [Accepted: 05/14/2013] [Indexed: 12/11/2022]
Abstract
Hemolysis results in the release of hemoglobin and heme into the bloodstream and is associated with the development of several pathologic conditions of different etiology, including hemoglobinopathies, hemolytic anemias, bacterial infections, malaria, and trauma. In addition, hemolysis is associated with surgical procedures, hemodialysis, blood transfusion, and other conditions in which mechanical forces can lead to red blood cell rupture. Free plasma hemoglobin and heme are toxic for the vascular endothelium since heme iron promotes oxidative stress that causes endothelial activation responsible for vasoocclusive events and thrombus formation. Moreover, free hemoglobin scavenges nitric oxide, reducing its bioavailability, and heme favours ROS production, thus causing oxidative nitric oxide consumption. This results in the dysregulation of the endothelium vasodilator:vasoconstrictor balance, leading to severe vasoconstriction and hypertension. Thus, endothelial dysfunction and impairment of cardiovascular function represent a common feature of pathologic conditions associated with hemolysis. In this review, we discuss how hemoglobin/heme released following hemolysis may affect vascular function and summarise the therapeutic approaches available to limit hemolysis-driven endothelial dysfunction. Particular emphasis is put on recent data showing the beneficial effects obtained through the use of the plasma heme scavenger hemopexin in counteracting heme-mediated endothelial damage in mouse models of hemolytic diseases.
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Burnette AD, Nimjee SM, Batchvarova M, Zennadi R, Telen MJ, Nishimura JI, Sullenger BA. RNA aptamer therapy for vaso-occlusion in sickle cell disease. Nucleic Acid Ther 2011; 21:275-83. [PMID: 21793788 DOI: 10.1089/nat.2010.0270] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Patients with sickle cell disease (SCD) often suffer painful vaso-occlusive episodes caused in part by the adhesion of sickle erythrocytes (SS-RBC) to the vascular endothelium. To investigate inhibition of SS-RBC adhesion as a possible treatment for vaso-occlusion, 2 adhesion molecules, α(v)β(3) and P-selectin, were targeted by high-affinity RNA aptamers. An in vitro flow chamber assay was used to test the antiadhesion activity of α(v)β(3) aptamer clone 17.16. Human SS-RBC were passed across a confluent monolayer of thrombin-stimulated human umbilical vein endothelial cells (HUVEC) at a constant rate. α(v)β(3) aptamer reduced SS-RBC adhesion to activated endothelial cells to the level seen with untreated HUVEC. An aptamer reactive with complement component 8 was used as a negative control and exerted no inhibition, confirming the specificity of α(v)β(3) aptamer (P=0.04). At 2 dyn/cm(2) shear stress, 30 nM α(v)β(3) aptamer showed maximal effect in decreasing SS-RBC adhesion to HUVEC. The antiadhesive activity of the P-selectin aptamer clone PF377 was also tested using HUVEC pretreated with IL-13 to upregulate expression of P-selectin as seen in activated endothelial cells. At 1 dyn/cm(2) shear stress, 60 nM of P-selectin aptamer had antiadhesion activity similar to heparin, a known inhibitor of SS-RBC adhesion to P-selectin. A negative control did not prevent adhesion (P=0.05). These data show the potential utility of aptamers to block endothelial adhesion molecules to prevent or treat vaso-occlusion in SCD.
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Affiliation(s)
- Angela D Burnette
- Department of Surgery, Duke University Medical Center , Durham, NC 27710, USA
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Miguel LI, Almeida CB, Traina F, Canalli AA, Dominical VM, Saad STO, Costa FF, Conran N. Inhibition of phosphodiesterase 9A reduces cytokine-stimulated in vitro adhesion of neutrophils from sickle cell anemia individuals. Inflamm Res 2011; 60:633-42. [PMID: 21336703 DOI: 10.1007/s00011-011-0315-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/22/2010] [Accepted: 02/01/2011] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Leukocyte adhesion to vessel walls may initiate vaso-occlusion in sickle cell anemia (SCA); however, the extent to which inflammation participates in this mechanism is not understood. This in vitro study investigated whether inflammatory molecules, commonly augmented in SCA, can affect neutrophil adhesive properties and whether cyclic guanosine monophosphate (cGMP)-elevating agents can inhibit such adhesion. SUBJECTS AND METHODS Effects of Interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α), granulocyte macrophage-colony stimulating factor (GM-CSF) cytokines, BAY 73-6691 [phosphodiesterase (PDE)-9A-inhibitor], and BAY 41-2271 (guanylate-cylase stimulator) on the adhesive properties of neutrophils from healthy control (CON) and steady-state SCA individuals were determined using static-adhesion assays. RESULTS SCA neutrophils demonstrated increased adhesive properties, compared to CON neutrophils; IL-8, TNF-α and GM-CSF increased CON neutrophil adhesion and further increased SCA neutrophil adhesion to fibronectin (FN). The PDE9A inhibitor, BAY-73-6691, significantly reduced basal CON neutrophil and SCA neutrophil adhesion; this was accompanied by decreased SCA neutrophil surface expressions of the L-selectin and CD11b adhesion molecules. BAY-73-6691 also significantly reduced cytokine-stimulated CON neutrophil and SCA neutrophil adhesion to FN; however, this was not accompanied by alterations in adhesion-molecule presentation. CONCLUSIONS The chronic inflammatory nature of SCA may contribute to leukocyte adhesive functions in SCA. Furthermore, elevation of leukocyte cGMP may be an interesting approach for inhibition of leukocyte adhesion to the vessel wall, even in the presence of inflammatory stimuli.
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Affiliation(s)
- Lediana Iagalo Miguel
- Hematology and Hemotherapy Center-Instituto Nacional de Ciência e Tecnologia do Sangue, University of Campinas-UNICAMP, Campinas, SP 13083-970, Brazil
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Inhibition of cell adhesion by anti-P-selectin aptamer: a new potential therapeutic agent for sickle cell disease. Blood 2010; 117:727-35. [PMID: 20926770 DOI: 10.1182/blood-2010-05-285718] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Adhesive interactions between circulating sickle red blood cells (RBCs), leukocytes, and endothelial cells are major pathophysiologic events in sickle cell disease (SCD). To develop new therapeutics that efficiently inhibit adhesive interactions, we generated an anti-P-selectin aptamer and examined its effects on cell adhesion using knockout-transgenic SCD model mice. Aptamers, single-stranded oligonucleotides that bind molecular targets with high affinity and specificity, are emerging as new therapeutics for cardiovascular and hematologic disorders. In vitro studies found that the anti-P-selectin aptamer exhibits high specificity to mouse P-selectin but not other selectins. SCD mice were injected with the anti-P-selectin aptamer, and cell adhesion was observed under hypoxia. The anti-P-selectin aptamer inhibited the adhesion of sickle RBCs and leukocytes to endothelial cells by 90% and 80%, respectively. The anti-P-selectin aptamer also increased microvascular flow velocities and reduced the leukocyte rolling flux. SCD mice treated with the anti-P-selectin aptamer demonstrated a reduced mortality rate associated with the experimental procedures compared with control mice. These results demonstrate that anti-P-selectin aptamer efficiently inhibits the adhesion of both sickle RBCs and leukocytes to endothelial cells in SCD model mice, suggesting a critical role for P-selectin in cell adhesion. Anti-P-selectin aptamer may be useful as a novel therapeutic agent for SCD.
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Pathophisiology of sickle cell disease and new drugs for the treatment. Mediterr J Hematol Infect Dis 2009; 1:e2009024. [PMID: 21415994 PMCID: PMC3033152 DOI: 10.4084/mjhid.2009.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 12/26/2009] [Indexed: 02/02/2023] Open
Abstract
A homozygous mutation in the gene for β globin, a subunit of adult hemoglobin A (HbA), is the proximate cause of sickle cell disease (SCD). Sickle hemoglobin (HbS) shows peculiar biochemical properties, which lead to polymerizing when deoxygenated. HbS polymerization is associated with a reduction in cell ion and water content (cell dehydration), increased red cell density which further accelerate HbS polymerization. Dense, dehydrated erythrocytes are likely to undergo instant polymerization in conditions of mild hypoxia due to their high HbS concentration, and HbS polymers may be formed under normal oxygen pressure. Pathophysiological studies have shown that the dense, dehydrated red cells may play a central role in acute and chronic clinical manifestations of sickle cell disease, in which intravascular sickling in capillaries and small vessels leads to vaso-occlusion and impaired blood flow in a variety of organs and tissue. The persistent membrane damage associated with HbS polymerization also favors the generation of distorted rigid cells and further contributes to vaso-occlusive crisis (VOCs) and cell destruction in the peripheral circulation. These damaged, dense sickle red cells also show a loss of phospholipid asymmetry with externalization of phosphatidylserine (PS), which is believed to play a significant role in promoting macrophage recognition with removal of erythrocytes (erythrophagocytosis). Vaso-occlusive events in the microcirculation result from a complex scenario involving the interactions between different cell types, including dense, dehydrated sickle cells, reticulocytes, abnormally activated endothelial cells, leukocytes, platelets and plasma factors such as cytokine and oxidized pro-inflammatory lipids. Hydroxycarbamide (hydroxyurea) is currently the only drug approved for chronic administration in adult patients with sickle cell disease to prevent acute painful crises and reduce the incidence of transfusion and acute chest crises. Here, we will focus on consolidated and experimental therapeutic strategies for the treatment of sickle cell disease, including:
agents which reduce or prevent sickle cell dehydration agents which reduce sickle cell-endothelial adhesive events nitric oxide (NO) or NO-related compounds anti-oxidant agents
Correction of the abnormalities ranging from membrane cation transport pathways to red cell-endothelial adhesive events, might constitute new pharmacological targets for treating sickle cell disease.
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Conran N, Costa FF. Hemoglobin disorders and endothelial cell interactions. Clin Biochem 2009; 42:1824-38. [PMID: 19580799 DOI: 10.1016/j.clinbiochem.2009.06.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/20/2009] [Indexed: 11/15/2022]
Abstract
Endothelial damage and inflammation make a significant contribution to the pathophysiology of sickle cell disease (SCD) and the beta-thalassemia syndromes. Endothelial dysfunction and ensuing vasculopathy are implicated in pulmonary hypertension in the hemoglobinopathies and endothelial activation and endothelial-blood cell adhesion, accompanied by inflammatory processes and oxidative stress, are imperative to the vaso-occlusive process in SCD. Herein, we discuss the role that the endothelium plays in all of these processes and the effect that genetic modifiers and hydroxyurea therapy may have upon endothelial interactions. Therapies targeting the endothelium and endothelial interactions may represent a promising approach for treating these diseases.
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Affiliation(s)
- Nicola Conran
- Hematology and Hemotherapy Centre, School of Medical Sciences, University of Campinas - UNICAMP, Brazil.
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Conran N, Franco-Penteado CF, Costa FF. Newer aspects of the pathophysiology of sickle cell disease vaso-occlusion. Hemoglobin 2009; 33:1-16. [PMID: 19205968 DOI: 10.1080/03630260802625709] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Sickle cell disease is an inherited disorder of hemoglobin (Hb) synthesis, caused by a single nucleotide substitution (GTG>GAG) at the sixth codon of the beta-globin gene, leading to the production of a defective form of Hb, Hb S. When deoxygenated, Hb S polymerizes, damaging the sickle erythrocyte and it is this polymerization that is the primary indispensable event in the molecular pathogenesis of sickle cell disease. Hb S polymerization results in a series of cellular alterations in red cell morphology and function that shorten the red cell life span and leads to vascular occlusion. Sickle cell disease vaso-occlusion is now known to constitute a complex multifactorial process characterized by recurrent vaso-occlusion, ischemia-reperfusion injury, and oxidative stress with consequent vascular endothelial cell activation that induces a chronic inflammatory state in sickle cell disease individual and is propagated by elevated levels of circulating inflammatory cytokines. Activation of the endothelium results in the induction of endothelial adhesion molecule expression that mediates red and white cell adhesion to the vessel wall and the formation of heterocellular aggregates, followed by secondary red cell trapping, all of which contribute to reduced blood flow and eventually obstruction of the micro-circulation. Reduced nitric oxide bioavailability, caused principally by its consumption by cell-free Hb, liberated during intravascular hemolysis, contributes to this process by facilitating vasoconstriction and adhesion molecule activity.
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Affiliation(s)
- Nicola Conran
- Hematology and Hemotherapy Center, School of Medical Sciences, UNICAMP, São Paulo, Brazil.
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Abstract
Periodic recurrence of painful vaso-occlusive crisis is the defining feature of sickle cell disease. Among multiple pathologies associated with this disease, sickle red cell-endothelium interaction has been implicated as a potential initiating mechanism in vaso-occlusive events. This review focuses on various interrelated mechanisms involved in human sickle red cell adhesion. We discuss in vitro and microcirculatory findings on sickle red cell adhesion, its potential role in vaso-occlusion, and the current understanding of receptor-ligand interactions involved in this pathological phenomenon. In addition, we discuss the contribution of other cellular interactions (leukocytes recruitment and leukocyte-red cell interaction) to vaso-occlusion, as observed in transgenic sickle mouse models. Emphasis is given to recently discovered adhesion molecules that play a predominant role in mediating human sickle red cell adhesion. Finally, we analyze various therapeutic approaches for inhibiting sickle red cell adhesion by targeting adhesion molecules and also consider therapeutic strategies that target stimuli involved in endothelial activation and initiation of adhesion.
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Affiliation(s)
- Dhananjay K Kaul
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Cartron JP, Elion J. Erythroid adhesion molecules in sickle cell disease: effect of hydroxyurea. Transfus Clin Biol 2008; 15:39-50. [PMID: 18515167 DOI: 10.1016/j.tracli.2008.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 05/05/2008] [Indexed: 01/02/2023]
Abstract
In sickle cell disease, the complex scenario of vaso-occlusive crisis (VOC) typical of this disease is clearly multifactorial and not fully understood. Cell-cell and cell-cell matrix interactions mediated by adhesive molecules present on blood cells and endothelial cells (ECs) are thought to play an important role. Early studies have shown that sickle red blood cells (RBCs) are abnormally adherent to ECs and some of the molecules involved in these interactions have been identified, such as the alpha4beta1 integrin and CD36, exclusively present on stress reticulocytes, and CD47 on mature RBCs. More recently, attention focused on Lu/BCAM, the unique RBC receptor for laminin, and on ICAM-4, a red cell-specific adhesion receptor, which is a ligand for a large repertoire of integrins (alphaLbeta2, alphaMbeta2, alphaxbeta2, alphaVbeta3). The counter-receptors on ECs and the role of plasma proteins forming bridges between blood cells and ECs have been clarified in part. It has also been shown that reticulocytes from SCD patients express higher levels of alpha4beta1 integrin and CD36, and that under hydroxyurea (HU) therapy, both cell adhesion to ECs or extracellular matrix proteins and the levels of these adhesion molecules are reduced. These findings are consistent with the view that enhanced adhesion of blood cells to ECs is largely determined by the membrane expression level of adhesion molecules and could be a crucial factor for triggering or aggravating vaso-occlusion. In SCD patients, membrane expression of Lu/BCAM (and perhaps ICAM-4) is enhanced on RBCs whose adherence to laminin or ECs is also increased. Interestingly, Lu/BCAM- and ICAM-4-mediated adhesion are enhanced by the stress mediator epinephrine through a PKA-dependent pathway initiated by a rise in intracellular cAMP and leading to receptor activation by phosphorylation according to the same signaling pathway. More recently, studies based on quantitative expression analysis of adhesion molecules on RBCs and during erythroid differentiation in patients undergoing HU therapy, surprisingly revealed that Lu/BCAM level was enhanced, although alpha4beta1, CD36 and ICAM-4 (to a lower extent) levels were indeed reduced. CD47 and CD147 expression were also enhanced in HU-treated patients. Based on these findings we suggest that the signalization cascade leading to receptor activation rather than the expression level only of adhesion molecules may be the critical factor regulating cell adhesion, although both mechanisms are not mutually exclusive.
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Affiliation(s)
- J-P Cartron
- Inserm U665, 6, rue Alexandre-Cabanel, 75015 Paris, France.
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Inati A, Koussa S, Taher A, Perrine S. Sickle cell disease: new insights into pathophysiology and treatment. Pediatr Ann 2008; 37:311-21. [PMID: 18543542 DOI: 10.3928/00904481-20080501-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Adlette Inati
- Rafik Hariri University Hospital, Division of Pediatric Hematology and Oncology, Beirut, Lebanon.
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