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Salih F, Schönborn L, Endres M, Greinacher A. Immunvermittelte Sinus- und Hirnvenenthrombosen: VITT und
prä-VITT als Modellerkrankung. AKTUEL RHEUMATOL 2022. [DOI: 10.1055/a-1936-3123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
ZusammenfassungIn diesem Übersichtsartikel beschreiben wir die klinischen und
paraklinischen Charakteristika der Vakzin-induzierten immunthrombotischen
Thrombozytopenie (VITT) und fassen den gegenwärtigen Kenntnisstand zur
Pathogenese zusammen. Bei der VITT bilden sich 5–20 Tage nach einer
Impfung mit einem Adenovirus-vektorbasiertem SARS-CoV-2-Vakzin (AstraZeneca oder
Johnson & Johnson) lebensbedrohliche Thrombosen aus, vor allem in den
zerebralen Sinus und Hirnvenen. Laborchemisch zeigt sich eine typische
Thrombozytopenie mit erhöhten D-Dimeren. Der Pathogenese liegen
immunologische Prozesse zugrunde, die Ähnlichkeiten mit der
Heparin-induzierten Thrombozytopenie aufweisen: so geht die VITT mit
hochtitrigem Immunoglobulin G gegen das thrombozytäre Protein
Plättchenfaktor 4 (PF4) einher. Durch die Interaktion mit dem Impfstoff
wird PF4 so verändert, dass es von Antikörper-produzierenden
Zellen des Immunsystems erkannt wird. Die so produzierten
Anti-PF4-Antikörper führen über thrombozytäre
FcγIIa-Rezeptoren zu einer Plättchenaktivierung. Der Nachweis
plättchenaktivierender Anti-PF4-Antikörper bestätigt die
Diagnose einer VITT. Antikoagulanzien, die die Bildung von Thrombin oder
Thrombin selbst blockieren und hochdosiertes i. v.-Immunglobulin G, das
die Fcγ-Rezeptor-vermittelte Zellaktivierung inhibiert, stellen die
wirksame und kausale Behandlung der VITT dar. Bei Patienten mit katastrophalem
Verlauf kann ein Plasmaaustausch versucht werden. Bei einigen Patienten ist ein
prä-VITT Syndrom als Prodromalstadium zu beoachten, das sich
typischerweise mit Kopfschmerzen manifestieren kann und dessen frühe
Behandlung hilft, thrombotische Komplikationen zu vermeiden. Die spezifische
Dynamik der VITT-assozierten Immunreaktion entspricht einer transienten,
sekundären Immunantwort. Aktuelle Studien gehen der Frage nach, wie PF4
an unterschiedliche adenovirale Proteine bindet und beleuchten die Rolle von
anderen Impfstoff-Bestandteilen als potentielle Liganden für die
PF4-Bindung. Einige dieser Faktoren sind auch an der Etablierung eines
proinflammatorischen Milieus („danger signal“) beteiligt, das
unmittelbar nach der Impfung die 1. Phase der VITT-Pathogenese triggert. Sobald
in der 2. Phase der VITT-Pathogenese hohe Titer von Anti-PF4-Antikörper
gebildet sind, aktivieren diese neben Thrombozyten auch Granulozyten. In einem
als NETose (von „neutrophil extracellular traps“) bezeichneten
Prozess setzen aktivierte Granulozyten dabei DNA frei, mit der PF4 weitere
Komplexe bildet, an die Anti-PF4-Antikörper binden. Dies
verstärkt die Fcγ-Rezeptor-vermittelte Zellaktivierung weiter
mit der Folge einer ausgeprägten Thrombin-Bildung. Zum Ende des Artikels
geben wir einen Ausblick, welchen Einfluss die bisherigen Erkenntnisse zur VITT
auf weitere globale Impfkampagnen gegen SARS-CoV-2 haben und beleuchten, wie
Anti-PF4-Antikörper jenseits von VITT und HIT auch eine Rolle bei
seltenen Erkrankungen spielen, die mit rezidivierenden venösen und
arteriellen Thrombosen einhergehen.
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Affiliation(s)
- Farid Salih
- Klinik für Neurologie mit Experimenteller Neurologie,
Charité Universitätsmedizin Berlin, Berlin,
Germany
| | - Linda Schönborn
- Institut für Transfusionsmedizin, Universitätsmedizin
Greifswald, Greifswald, Germany
| | - Matthias Endres
- Klinik für Neurologie mit Experimenteller Neurologie,
Charité Universitätsmedizin Berlin, Berlin,
Germany
| | - Andreas Greinacher
- Institut für Transfusionsmedizin, Universitätsmedizin
Greifswald, Greifswald, Germany
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Barua D, Winklbauer R. Eph/ephrin signaling controls cell contacts and formation of a structurally asymmetrical tissue boundary in the Xenopus gastrula. Dev Biol 2022; 490:73-85. [PMID: 35868403 DOI: 10.1016/j.ydbio.2022.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/05/2022] [Accepted: 07/14/2022] [Indexed: 11/29/2022]
Abstract
In the primitive vertebrate gastrula, the boundary between ectoderm and mesoderm is formed by Brachet's cleft. Here we examine Brachet's cleft and its control by Eph/ephrin signaling in Xenopus at the ultrastructural level and by visualizing cortical F-actin. We infer cortical tension ratios at tissue surfaces and their interface in normal gastrulae and after depletion of receptors EphB4 and EphA4 and ligands ephrinB2 and ephrinB3. We find that cortical tension downregulation at cell contacts, a normal process in adhesion, is asymmetrically blocked in the ectoderm by Eph/ephrin signals from the mesoderm. This generates high interfacial tension that can prevent cell mixing across the boundary. Moreover, it determines an asymmetric boundary structure that is suited for the respective roles of ectoderm and mesoderm, as substratum and as migratory layers. The Eph and ephrin isoforms also control different cell-cell contact types in ectoderm and mesoderm. Respective changes of adhesion upon isoform depletion affect adhesion at the boundary to different degrees but usually do not prohibit cleft formation. In an extreme case, a new type of cleft-like boundary is even generated where cortical tension is symmetrically increased on both sides of the boundary.
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Affiliation(s)
- Debanjan Barua
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.
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Greinacher A, Schönborn L, Siegerist F, Steil L, Palankar R, Handtke S, Reder A, Thiele T, Aurich K, Methling K, Lalk M, Völker U, Endlich N. Pathogenesis of vaccine-induced immune thrombotic thrombocytopenia (VITT). Semin Hematol 2022; 59:97-107. [PMID: 35512907 PMCID: PMC8863951 DOI: 10.1053/j.seminhematol.2022.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 02/16/2022] [Indexed: 02/06/2023]
Abstract
Vaccine-induced immune thrombotic thrombocytopenia (VITT; synonym, thrombosis with thrombocytopenia syndrome, is associated with high-titer immunoglobulin G antibodies directed against platelet factor 4 (PF4). These antibodies activate platelets via platelet FcγIIa receptors, with platelet activation greatly enhanced by PF4. Here we summarize the current concepts in the pathogenesis of VITT. We first address parallels between heparin-induced thrombocytopenia and VITT, and provide recent findings on binding of PF4 to adenovirus particles and non-assembled adenovirus proteins in the 2 adenovirus vector-based COVID-19 vaccines, ChAdOx1 nCoV-19 and Ad26.COV2.S. Further, we discuss the potential role of vaccine constituents such as glycosaminoglycans, EDTA, polysorbate 80, human cell-line proteins and nucleotides as potential binding partners of PF4. The immune response towards PF4 in VITT is likely triggered by a proinflammatory milieu. Human cell-line proteins, non-assembled virus proteins, and potentially EDTA may contribute to the proinflammatory state. The transient nature of the immune response towards PF4 in VITT makes it likely that-as in heparin-induced thrombocytopenia -marginal zone B cells are key for antibody production. Once high-titer anti-PF4 antibodies have been formed 5 to 20 days after vaccination, they activate platelets and granulocytes. Activated granulocytes undergo NETosis and the released DNA also forms complexes with PF4, which fuels the Fcγ receptor-dependent cell activation process, ultimately leading to massive thrombin generation. Finally, we summarize our initial observations indicating that VITT-like antibodies might also be present in rare patients with recurrent venous and arterial thrombotic complications, independent of vaccination.
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Affiliation(s)
- Andreas Greinacher
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany,Corresponding author: Prof. Dr Andreas Greinacher, Institut für Transfusions medizin, Universitätsmedizin Greifswald, Sauerbruchstraße, D-17489 Greifswald, Germany. Tel: +49 383 486 5482; fax: +49 383 486 5489
| | - Linda Schönborn
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Florian Siegerist
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Leif Steil
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Raghavendra Palankar
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Stefan Handtke
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Alexander Reder
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Thomas Thiele
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Konstanze Aurich
- Institute of Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Karen Methling
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute of Genetics and Functional Genomics, Department Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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Alban S, Neupane S, Girreser U, Sönnichsen FD, Greinacher A. The COVID-19 vaccine ChAdOx1-S is not contaminated with sulfated glycosaminoglycans. J Thromb Haemost 2022; 20:777-780. [PMID: 34971474 PMCID: PMC9906281 DOI: 10.1111/jth.15633] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 12/01/2022]
Affiliation(s)
- Susanne Alban
- Pharmazeutisches Institut, Abteilung Pharmazeutische Biologie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Sandesh Neupane
- Pharmazeutisches Institut, Abteilung Pharmazeutische Biologie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Ulrich Girreser
- Pharmazeutisches Institut, Abteilung Pharmazeutische Chemie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Frank D Sönnichsen
- Otto Diels Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Andreas Greinacher
- Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
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Haimson B, Meir O, Sudakevitz-Merzbach R, Elberg G, Friedrich S, Lovell PV, Paixão S, Klein R, Mello CV, Klar A. Natural loss of function of ephrin-B3 shapes spinal flight circuitry in birds. SCIENCE ADVANCES 2021; 7:7/24/eabg5968. [PMID: 34117069 PMCID: PMC8195482 DOI: 10.1126/sciadv.abg5968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/28/2021] [Indexed: 05/11/2023]
Abstract
Flight in birds evolved through patterning of the wings from forelimbs and transition from alternating gait to synchronous flapping. In mammals, the spinal midline guidance molecule ephrin-B3 instructs the wiring that enables limb alternation, and its deletion leads to synchronous hopping gait. Here, we show that the ephrin-B3 protein in birds lacks several motifs present in other vertebrates, diminishing its affinity for the EphA4 receptor. The avian ephrin-B3 gene lacks an enhancer that drives midline expression and is missing in galliforms. The morphology and wiring at brachial levels of the chicken embryonic spinal cord resemble those of ephrin-B3 null mice. Dorsal midline decussation, evident in the mutant mouse, is apparent at the chick brachial level and is prevented by expression of exogenous ephrin-B3 at the roof plate. Our findings support a role for loss of ephrin-B3 function in shaping the avian brachial spinal cord circuitry and facilitating synchronous wing flapping.
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Affiliation(s)
- Baruch Haimson
- Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Oren Meir
- Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Reut Sudakevitz-Merzbach
- Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Gerard Elberg
- Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Samantha Friedrich
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Peter V Lovell
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Sónia Paixão
- Department Molecules-Signaling-Development, Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Rüdiger Klein
- Department Molecules-Signaling-Development, Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA.
| | - Avihu Klar
- Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.
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Prydz K, Halstensen TS, Holen HL, Aasheim HC. Ephrin-B3 binds both cell-associated and secreted proteoglycans. Biochem Biophys Res Commun 2018; 503:2212-2217. [PMID: 29953858 DOI: 10.1016/j.bbrc.2018.06.140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
Abstract
The ephrin family of membrane proteins binds Eph tyrosine kinase receptors. We have previously shown that ephrin-B3 also binds to heparan sulfate proteoglycans (HSPGs). We now show that ephrin-B3 can bind both secretory and cell associated PGs, such as agrin, collagen XVIII, Perlecan, and CD44, and indicate that such interaction with cell associated PGs involves a complex including 20 and 45 kDa proteins. Ephrin-B3 binding to HEK-293T cells is blocked by a secretory variant of CD44 (v3-v10), while over-expression of membrane associated CD44 increased ephrin-B3 binding. In addition, ephrin-B3 precipitated CD44 expressed by the oral squamous carcinoma cell line H376. Moreover, ephrin-B3 binding affinities to heparin and CD44 in solution was strong. In conclusion, we have identified secretory and cell associated PGs with high ability to bind ephrin-B3 and suggest that ephrin-B3 can bind to a protein complex organized by a membrane associated PG.
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Affiliation(s)
- Kristian Prydz
- Department of Biosciences, University of Oslo, Box 1066, Blindern, NO-0316, Oslo, Norway
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The Caenorhabditis elegans Ephrin EFN-4 Functions Non-cell Autonomously with Heparan Sulfate Proteoglycans to Promote Axon Outgrowth and Branching. Genetics 2015; 202:639-60. [PMID: 26645816 DOI: 10.1534/genetics.115.185298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/02/2015] [Indexed: 01/21/2023] Open
Abstract
The Eph receptors and their cognate ephrin ligands play key roles in many aspects of nervous system development. These interactions typically occur within an individual tissue type, serving either to guide axons to their terminal targets or to define boundaries between the rhombomeres of the hindbrain. We have identified a novel role for the Caenorhabditis elegans ephrin EFN-4 in promoting primary neurite outgrowth in AIY interneurons and D-class motor neurons. Rescue experiments reveal that EFN-4 functions non-cell autonomously in the epidermis to promote primary neurite outgrowth. We also find that EFN-4 plays a role in promoting ectopic axon branching in a C. elegans model of X-linked Kallmann syndrome. In this context, EFN-4 functions non-cell autonomously in the body-wall muscle and in parallel with HS modification genes and HSPG core proteins. This is the first report of an epidermal ephrin providing a developmental cue to the nervous system.
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Abstract
UNLABELLED Nipah virus and Hendra virus are emerging, highly pathogenic, zoonotic paramyxoviruses that belong to the genus Henipavirus. They infect humans as well as numerous mammalian species. Both viruses use ephrin-B2 and -B3 as cell entry receptors, and following initial entry into an organism, they are capable of rapid spread throughout the host. We have previously reported that Nipah virus can use another attachment receptor, different from its entry receptors, to bind to nonpermissive circulating leukocytes, thereby promoting viral dissemination within the host. Here, this attachment molecule was identified as heparan sulfate for both Nipah virus and Hendra virus. Cells devoid of heparan sulfate were not able to mediate henipavirus trans-infection and showed reduced permissivity to infection. Virus pseudotyped with Nipah virus glycoproteins bound heparan sulfate and heparin but no other glycosaminoglycans in a surface plasmon resonance assay. Furthermore, heparin was able to inhibit the interaction of the viruses with the heparan sulfate and to block cell-mediated trans-infection of henipaviruses. Moreover, heparin was shown to bind to ephrin-B3 and to restrain infection of permissive cells in vitro. Consequently, treatment with heparin devoid of anticoagulant activity improved the survival of Nipah virus-infected hamsters. Altogether, these results reveal heparan sulfate as a new attachment receptor for henipaviruses and as a potential therapeutic target for the development of novel approaches against these highly lethal infections. IMPORTANCE The Henipavirus genus includes two closely related, highly pathogenic paramyxoviruses, Nipah virus and Hendra virus, which cause elevated morbidity and mortality in animals and humans. Pathogenesis of both Nipah virus and Hendra virus infection is poorly understood, and efficient antiviral treatment is still missing. Here, we identified heparan sulfate as a novel attachment receptor used by both viruses to bind host cells. We demonstrate that heparin was able to inhibit the interaction of the viruses with heparan sulfate and to block cell-mediated trans-infection of henipaviruses. Moreover, heparin also bound to the viral entry receptor and thereby restricted infection of permissive cells in vitro. Consequently, heparin treatment improved survival of Nipah virus-infected hamsters. These results uncover an important role of heparan sulfate in henipavirus infection and open novel perspectives for the development of heparan sulfate-targeting therapeutic approaches for these emerging infections.
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Falivelli G, Lisabeth EM, de la Torre ER, Perez-Tenorio G, Tosato G, Salvucci O, Pasquale EB. Attenuation of eph receptor kinase activation in cancer cells by coexpressed ephrin ligands. PLoS One 2013; 8:e81445. [PMID: 24348920 PMCID: PMC3857839 DOI: 10.1371/journal.pone.0081445] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/21/2013] [Indexed: 12/20/2022] Open
Abstract
The Eph receptor tyrosine kinases mediate juxtacrine signals by interacting “in trans” with ligands anchored to the surface of neighboring cells via a GPI-anchor (ephrin-As) or a transmembrane segment (ephrin-Bs), which leads to receptor clustering and increased kinase activity. Additionally, soluble forms of the ephrin-A ligands released from the cell surface by matrix metalloproteases can also activate EphA receptor signaling. Besides these trans interactions, recent studies have revealed that Eph receptors and ephrins coexpressed in neurons can also engage in lateral “cis” associations that attenuate receptor activation by ephrins in trans with critical functional consequences. Despite the importance of the Eph/ephrin system in tumorigenesis, Eph receptor-ephrin cis interactions have not been previously investigated in cancer cells. Here we show that in cancer cells, coexpressed ephrin-A3 can inhibit the ability of EphA2 and EphA3 to bind ephrins in trans and become activated, while ephrin-B2 can inhibit not only EphB4 but also EphA3. The cis inhibition of EphA3 by ephrin-B2 implies that in some cases ephrins that cannot activate a particular Eph receptor in trans can nevertheless inhibit its signaling ability through cis association. We also found that an EphA3 mutation identified in lung cancer enhances cis interaction with ephrin-A3. These results suggest a novel mechanism that may contribute to cancer pathogenesis by attenuating the tumor suppressing effects of Eph receptor signaling pathways activated by ephrins in trans.
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Affiliation(s)
- Giulia Falivelli
- Sanford-Burnham Medical Research Institute, San Diego, California, United States of America
- Department Pharmacology, University of Bologna, Bologna, Italy
| | - Erika Mathes Lisabeth
- Sanford-Burnham Medical Research Institute, San Diego, California, United States of America
| | | | - Gizeh Perez-Tenorio
- Sanford-Burnham Medical Research Institute, San Diego, California, United States of America
| | - Giovanna Tosato
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ombretta Salvucci
- Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Elena B. Pasquale
- Sanford-Burnham Medical Research Institute, San Diego, California, United States of America
- Department of Pathology, University of California San Diego, San Diego, California, United States of America
- * E-mail:
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Lisabeth EM, Falivelli G, Pasquale EB. Eph receptor signaling and ephrins. Cold Spring Harb Perspect Biol 2013; 5:5/9/a009159. [PMID: 24003208 DOI: 10.1101/cshperspect.a009159] [Citation(s) in RCA: 292] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Eph receptors are the largest of the RTK families. Like other RTKs, they transduce signals from the cell exterior to the interior through ligand-induced activation of their kinase domain. However, the Eph receptors also have distinctive features. Instead of binding soluble ligands, they generally mediate contact-dependent cell-cell communication by interacting with surface-associated ligands-the ephrins-on neighboring cells. Eph receptor-ephrin complexes emanate bidirectional signals that affect both receptor- and ephrin-expressing cells. Intriguingly, ephrins can also attenuate signaling by Eph receptors coexpressed in the same cell. Additionally, Eph receptors can modulate cell behavior independently of ephrin binding and kinase activity. The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. Its abnormal function has been implicated in various diseases, including cancer. Thus, Eph receptors represent promising therapeutic targets. However, more research is needed to better understand the many aspects of their complex biology that remain mysterious.
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Affiliation(s)
- Erika M Lisabeth
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
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Abstract
Cancer cells rely on intercellular communication throughout the different stages of their transformation and progression into metastasis. They do so by co-opting different processes such as cell-cell junctions, growth factors, receptors, and vesicular release. Initially characterized in neuronal and vascular tissues, Ephs and Ephrins, the largest family of receptor tyrosine kinases, comprised of two classes (i.e., A and B types), is increasingly scrutinized by cancer researchers. These proteins possess the particular features of both the receptors and ligands being membrane-bound which, via mandatory direct cell-cell interactions, undergo a bidirectional signal transduction initiated from both the receptor and the ligand. Following cell-cell interactions, Ephs/Ephrins behave as guidance molecules which trigger both repulsive and attractive signals, so as to direct the movement of cells through their immediate microenvironment. They also direct processes which include sorting and positioning and cytoskeleton rearrangements, thus making them perfect candidates for the control of the metastatic process. In fact, the role of Ephs and Ephrins in cancer progression has been demonstrated for many of the family members and they, surprisingly, have both tumor promoter and suppressor functions in different cellular contexts. They are also able to coordinate between multiple processes including cell survival, proliferation, differentiation, adhesion, motility, and invasion. This review is an attempt to summarize the data available on these Ephs/Ephrins' biological functions which contribute to the onset of aggressive cancers. I will also provide an overview of the factors which could explain the functional differences demonstrated by Ephs and Ephrins at different stages of tumor progression and whose elucidation is warranted for any future therapeutic targeting of this signaling pathway in cancer metastasis.
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Nievergall E, Lackmann M, Janes PW. Eph-dependent cell-cell adhesion and segregation in development and cancer. Cell Mol Life Sci 2012; 69:1813-42. [PMID: 22204021 PMCID: PMC11114713 DOI: 10.1007/s00018-011-0900-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/06/2011] [Accepted: 11/28/2011] [Indexed: 01/23/2023]
Abstract
Numerous studies attest to essential roles for Eph receptors and their ephrin ligands in controlling cell positioning and tissue patterning during normal and oncogenic development. These studies suggest multiple, sometimes contradictory, functions of Eph-ephrin signalling, which under different conditions can promote either spreading and cell-cell adhesion or cytoskeletal collapse, cell rounding, de-adhesion and cell-cell segregation. A principle determinant of the balance between these two opposing responses is the degree of receptor/ligand clustering and activation. This equilibrium is likely altered in cancers and modulated by somatic mutations of key Eph family members that have emerged as candidate cancer markers in recent profiling studies. In addition, cross-talk amongst Ephs and with other signalling pathways significantly modulates cell-cell adhesion, both between and within Eph- and ephrin-expressing cell populations. This review summarises our current understanding of how Eph receptors control cell adhesion and morphology, and presents examples demonstrating the importance of these events in normal development and cancer.
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Affiliation(s)
- Eva Nievergall
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
- Present Address: Haematology Department, SA Pathology, Frome Road, Adelaide, SA 5000 Australia
| | - Martin Lackmann
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
| | - Peter W. Janes
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800 Australia
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Noberini R, Rubio de la Torre E, Pasquale EB. Profiling Eph receptor expression in cells and tissues: a targeted mass spectrometry approach. Cell Adh Migr 2012; 6:102-12. [PMID: 22568954 DOI: 10.4161/cam.19620] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The Eph receptor tyrosine kinase family includes many members, which are often expressed together in various combinations and can promiscuously interact with multiple ephrin ligands, generating intricate networks of intracellular signals that control physiological and pathological processes. Knowing the entire repertoire of Eph receptors and ephrins expressed in a biological sample is important when studying their biological roles. Moreover, given the correlation between Eph receptor/ephrin expression and cancer pathogenesis, their expression patterns could serve important diagnostic and prognostic purposes. However, profiling Eph receptor and ephrin expression has been challenging. Here we describe a novel and straightforward approach to catalog the Eph receptors present in cultured cells and tissues. By measuring the binding of ephrin Fc fusion proteins to Eph receptors in ELISA and pull-down assays, we determined that a mixture of four ephrins is suitable for isolating both EphA and EphB receptors in a single pull-down. We then used mass spectrometry to identify the Eph receptors present in the pull-downs and estimate their relative levels. This approach was validated in cultured human cancer cell lines, human tumor xenograft tissue grown in mice, and mouse brain tissue. The new mass spectrometry approach we have developed represents a useful tool for the identification of the spectrum of Eph receptors present in a biological sample and could also be extended to profiling ephrin expression.
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Holen HL, Zernichow L, Fjelland KE, Evenroed IM, Tveit H, Aasheim HC. Ephrin-B3 binds specifically to B lymphocytes in blood and induces migration. Scand J Immunol 2011; 74:144-54. [PMID: 21447033 DOI: 10.1111/j.1365-3083.2011.02563.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Eph receptors and ephrin ligands have been shown to be differentially expressed on leucocytes. Here, we show that one member of the ephrin-B subfamily of ephrins, ephrin-B3, specifically binds to B lymphocytes in blood. No binding was observed to T lymphocytes or monocytes. The ephrin-B3 binding receptor on B lymphocytes is so far not identified, but our results here indicate that ephrin-B3 binds to a protein not belonging to the Eph receptor family. Recently, we have shown that ephrin-B3 binds to a sulphated cell surface receptor on HEK293T cells and that this binding can be blocked with heparin. Ephrin-B3 binding to B lymphocytes is partially affected by heparin, and a basic amino acid in the extracellular juxtamembrane region, Arg-188, is here shown to be involved in this binding. The functional consequence of ephrin-B3 binding to B lymphocytes is induced migration, in particular of the memory cells. To conclude, ephrin-B3 binds to B lymphocytes, most likely via a non-classical receptor, and induces migration of the memory B cell subpopulation.
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Affiliation(s)
- H L Holen
- Department of Medical Genetics, Oslo University Hospital, Ullevaal, Oslo, Norway
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Ogata-Iwao M, Inatani M, Iwao K, Takihara Y, Nakaishi-Fukuchi Y, Irie F, Sato S, Furukawa T, Yamaguchi Y, Tanihara H. Heparan sulfate regulates intraretinal axon pathfinding by retinal ganglion cells. Invest Ophthalmol Vis Sci 2011; 52:6671-9. [PMID: 21743013 DOI: 10.1167/iovs.11-7559] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE. Heparan sulfate (HS) is abundantly expressed in the developing neural retina; however, its role in the intraretinal axon guidance of retinal ganglion cells (RGCs) remains unclear. In this study, the authors examined whether HS was essential for the axon guidance of RGCs toward the optic nerve head. METHODS. The authors conditionally ablated the gene encoding the exostosin-1 (Ext1) enzyme, using the dickkopf homolog 3 (Dkk3)-Cre transgene, which disrupted HS expression in the mouse retina during directed pathfinding by RGC axons toward the optic nerve head. In situ hybridization, immunohistochemistry, DiI tracing, binding assay, and retinal explant assays were performed to evaluate the phenotypes of the mutants and the roles of HS in intraretinal axon guidance. RESULTS. Despite no gross abnormality in RGC distribution, the mutant RGC axons exhibited severe intraretinal guidance errors, including optic nerve hypoplasia, ectopic axon penetration through the full thickness of the neural retina and into the subretinal space, and disturbance of the centrifugal projection of RGC axons toward the optic nerve head. These abnormal phenotypes shared similarities with the RGC axon misguidance caused by mutations of genes encoding Netrin-1 and Slit-1/2. Explant assays revealed that the mutant RGCs exhibited disturbed Netrin-1-dependent axon outgrowth and Slit-2-dependent repulsion. CONCLUSIONS. The present study demonstrated that RGC axon projection toward the optic nerve head requires the expression of HS in the neural retina, suggesting that HS in the retina functions as an essential modulator of Netrin-1 and Slit-mediated intraretinal RGC axon guidance.
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Affiliation(s)
- Minako Ogata-Iwao
- Department of Ophthalmology and Visual Science, Kumamoto University Graduate School of Medical Sciences, Japan
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