1
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Faivre N, Verollet C, Dumas F. The chemokine receptor CCR5: multi-faceted hook for HIV-1. Retrovirology 2024; 21:2. [PMID: 38263120 PMCID: PMC10807162 DOI: 10.1186/s12977-024-00634-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/13/2024] [Indexed: 01/25/2024] Open
Abstract
Chemokines are cytokines whose primary role is cellular activation and stimulation of leukocyte migration. They perform their various functions by interacting with G protein-coupled cell surface receptors (GPCRs) and are involved in the regulation of many biological processes such as apoptosis, proliferation, angiogenesis, hematopoiesis or organogenesis. They contribute to the maintenance of the homeostasis of lymphocytes and coordinate the function of the immune system. However, chemokines and their receptors are sometimes hijacked by some pathogens to infect the host organism. For a given chemokine receptor, there is a wide structural, organizational and conformational diversity. In this review, we describe the evidence for structural variety reported for the chemokine receptor CCR5, how this variability can be exploited by HIV-1 to infect its target cells and what therapeutic solutions are currently being developed to overcome this problem.
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Affiliation(s)
- Natacha Faivre
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
- International Research Laboratory (IRP) CNRS "IM-TB/HIV", Toulouse, France
- International Research Laboratory (IRP) CNRS "IM-TB/HIV", Buenos Aires, Argentina
| | - Christel Verollet
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
- International Research Laboratory (IRP) CNRS "IM-TB/HIV", Toulouse, France
- International Research Laboratory (IRP) CNRS "IM-TB/HIV", Buenos Aires, Argentina
| | - Fabrice Dumas
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France.
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2
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Timmers M, Peeters W, Hauwert NJ, Rijcken CJF, Vermonden T, Dijkgraaf I, Liskamp RMJ. Specific N-terminal attachment of TMTHSI linkers to native peptides and proteins for strain-promoted azide alkyne cycloaddition. Chem Commun (Camb) 2023; 59:11397-11400. [PMID: 37668179 DOI: 10.1039/d3cc03397j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The site specific attachment of the reactive TMTHSI-click handle to the N-terminus of peptides and proteins is described. The resulting molecular constructs can be used in strain-promoted azide alkyne cycloaddition (SPAAC) for reaction with azide containing proteins e.g., antibodies, peptides, nanoparticles, fluorescent dyes, chelators for radioactive isotopes and SPR-chips etc.
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Affiliation(s)
- Matt Timmers
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht 3584 CG, The Netherlands
- Cristal Therapeutics, Maastricht 6229 EV, The Netherlands
| | - Wouter Peeters
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht 6229 ER, The Netherlands
| | | | | | - Tina Vermonden
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht 3584 CG, The Netherlands
| | - Ingrid Dijkgraaf
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht 6229 ER, The Netherlands
| | - Rob M J Liskamp
- Cristal Therapeutics, Maastricht 6229 EV, The Netherlands
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht 6229 ER, The Netherlands
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
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3
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Blanchet X, Weber C, von Hundelshausen P. Chemokine Heteromers and Their Impact on Cellular Function-A Conceptual Framework. Int J Mol Sci 2023; 24:10925. [PMID: 37446102 DOI: 10.3390/ijms241310925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
Chemoattractant cytokines or chemokines are proteins involved in numerous biological activities. Their essential role consists of the formation of gradient and (immune) cell recruitment. Chemokine biology and its related signaling system is more complex than simple ligand-receptor interactions. Beside interactions with their cognate and/or atypical chemokine receptors, and glycosaminoglycans (GAGs), chemokines form complexes with themselves as homo-oligomers, heteromers and also with other soluble effector proteins, including the atypical chemokine MIF, carbohydrate-binding proteins (galectins), damage-associated molecular patterns (DAMPs) or with chemokine-binding proteins such as evasins. Likewise, nucleic acids have been described as binding targets for the tetrameric form of CXCL4. The dynamic balance between monomeric and dimeric structures, as well as interactions with GAGs, modulate the concentrations of free chemokines available along with the nature of the gradient. Dimerization of chemokines changes the canonical monomeric fold into two main dimeric structures, namely CC- and CXC-type dimers. Recent studies highlighted that chemokine dimer formation is a frequent event that could occur under pathophysiological conditions. The structural changes dictated by chemokine dimerization confer additional biological activities, e.g., biased signaling. The present review will provide a short overview of the known functionality of chemokines together with the consequences of the interactions engaged by the chemokines with other proteins. Finally, we will present potential therapeutic tools targeting the chemokine multimeric structures that could modulate their biological functions.
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Affiliation(s)
- Xavier Blanchet
- Institute for Cardiovascular Prevention (IPEK), LMU Munich, 80336 Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention (IPEK), LMU Munich, 80336 Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, 80636 Munich, Germany
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands
| | - Philipp von Hundelshausen
- Institute for Cardiovascular Prevention (IPEK), LMU Munich, 80336 Munich, Germany
- German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, 80636 Munich, Germany
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A Deeper Insight into the Tick Salivary Protein Families under the Light of Alphafold2 and Dali: Introducing the TickSialoFam 2.0 Database. Int J Mol Sci 2022; 23:ijms232415613. [PMID: 36555254 PMCID: PMC9779611 DOI: 10.3390/ijms232415613] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
Hard ticks feed for several days or weeks on their hosts and their saliva contains thousands of polypeptides belonging to dozens of families, as identified by salivary transcriptomes. Comparison of the coding sequences to protein databases helps to identify putative secreted proteins and their potential functions, directing and focusing future studies, usually done with recombinant proteins that are tested in different bioassays. However, many families of putative secreted peptides have a unique character, not providing significant matches to known sequences. The availability of the Alphafold2 program, which provides in silico predictions of the 3D polypeptide structure, coupled with the Dali program which uses the atomic coordinates of a structural model to search the Protein Data Bank (PDB) allows another layer of investigation to annotate and ascribe a functional role to proteins having so far being characterized as "unique". In this study, we analyzed the classification of tick salivary proteins under the light of the Alphafold2/Dali programs, detecting novel protein families and gaining new insights relating the structure and function of tick salivary proteins.
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5
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Strobl J, Mündler V, Müller S, Gindl A, Berent S, Schötta AM, Kleissl L, Staud C, Redl A, Unterluggauer L, Aguilar González AE, Weninger ST, Atzmüller D, Klasinc R, Stanek G, Markowicz M, Stockinger H, Stary G. Tick feeding modulates the human skin immune landscape to facilitate tick-borne pathogen transmission. J Clin Invest 2022; 132:e161188. [PMID: 36166299 PMCID: PMC9621130 DOI: 10.1172/jci161188] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
During cutaneous tick attachment, the feeding cavity becomes a site of transmission for tick salivary compounds and tick-borne pathogens. However, the immunological consequences of tick feeding for human skin remain unclear. Here, we assessed human skin and blood samples upon tick bite and developed a human skin explant model mimicking Ixodes ricinus bites and tick-borne pathogen infection. Following tick attachment, we observed rapidly occurring patterns of immunomodulation, including increases in neutrophils and cutaneous B and T cells. T cells upregulated tissue residency markers, while lymphocytic cytokine production was impaired. In early stages of Borrelia burgdorferi model infections, we detected strain-specific immune responses and close spatial relationships between macrophages and spirochetes. Preincubation of spirochetes with tick salivary gland extracts hampered accumulation of immune cells and increased spirochete loads. Collectively, we showed that tick feeding exerts profound changes on the skin immune network that interfere with the primary response against tick-borne pathogens.
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Affiliation(s)
- Johanna Strobl
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Verena Mündler
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Sophie Müller
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Anna Gindl
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Sara Berent
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Anna-Margarita Schötta
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Lisa Kleissl
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Clement Staud
- Department of Plastic and Reconstructive Surgery, Medical University of Vienna, Vienna, Austria
| | - Anna Redl
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | | | | | - Sophie T. Weninger
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Denise Atzmüller
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
| | - Romana Klasinc
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gerold Stanek
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Mateusz Markowicz
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- Austrian Agency for Health and Food Safety (AGES), Vienna, Austria
| | - Hannes Stockinger
- Institute for Hygiene and Applied Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Georg Stary
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
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6
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Bhattacharya S, Nuttall PA. Phylogenetic Analysis Indicates That Evasin-Like Proteins of Ixodid Ticks Fall Into Three Distinct Classes. Front Cell Infect Microbiol 2021; 11:769542. [PMID: 34746035 PMCID: PMC8569228 DOI: 10.3389/fcimb.2021.769542] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/24/2021] [Indexed: 12/22/2022] Open
Abstract
Chemokines are structurally related proteins that activate leucocyte migration in response to injury or infection. Tick saliva contains chemokine-binding proteins or evasins which likely neutralize host chemokine function and inflammation. Biochemical characterisation of 50 evasins from Ixodes, Amblyomma and Rhipicephalus shows that they fall into two functional classes, A and B, with exclusive binding to either CC- or CXC- chemokines, respectively. Class A evasins, EVA1 and EVA4 have a four-disulfide-bonded core, whereas the class B evasin EVA3 has a three-disulfide-bonded “knottin” structure. All 29 class B evasins have six cysteine residues conserved with EVA3, arrangement of which defines a Cys6-motif. Nineteen of 21 class A evasins have eight cysteine residues conserved with EVA1/EVA4, the arrangement of which defines a Cys8-motif. Two class A evasins from Ixodes (IRI01, IHO01) have less than eight cysteines. Many evasin-like proteins have been identified in tick salivary transcriptomes, but their phylogenetic relationship with respect to biochemically characterized evasins is not clear. Here, using BLAST searches of tick transcriptomes with biochemically characterized evasins, we identify 292 class A and 157 class B evasins and evasin-like proteins from Prostriate (Ixodes), and Metastriate (Amblyomma, Dermacentor, Hyalomma, Rhipicephalus) ticks. Phylogenetic analysis shows that class A evasins/evasin-like proteins segregate into two classes, A1 and A2. Class A1 members are exclusive to Metastriate ticks and typically have a Cys8-motif and include EVA1 and EVA4. Class A2 members are exclusive to Prostriate ticks, lack the Cys8-motif, and include IHO01 and IRI01. Class B evasins/evasin-like proteins are present in both Prostriate and Metastriate lineages, typically have a Cys6-motif, and include EVA3. Most evasins/evasin-like proteins in Metastriate ticks belong to class A1, whereas in Prostriate species they are predominantly class B. In keeping with this, the majority of biochemically characterized Metastriate evasins bind CC-chemokines, whereas the majority of Prostriate evasins bind CXC-chemokines. While the origin of the structurally dissimilar classes A1 and A2 is yet unresolved, these results suggest that class B evasin-like proteins arose before the divergence of Prostriate and Metastriate lineages and likely functioned to neutralize CXC-chemokines and support blood feeding.
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Affiliation(s)
- Shoumo Bhattacharya
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.,National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford University Hospitals National Health Service (NHS) Foundation Trust, Oxford, United Kingdom
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7
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Denisov SS, Dijkgraaf I. Immunomodulatory Proteins in Tick Saliva From a Structural Perspective. Front Cell Infect Microbiol 2021; 11:769574. [PMID: 34722347 PMCID: PMC8548845 DOI: 10.3389/fcimb.2021.769574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/28/2021] [Indexed: 12/25/2022] Open
Abstract
To feed successfully, ticks must bypass or suppress the host’s defense mechanisms, particularly the immune system. To accomplish this, ticks secrete specialized immunomodulatory proteins into their saliva, just like many other blood-sucking parasites. However, the strategy of ticks is rather unique compared to their counterparts. Ticks’ tendency for gene duplication has led to a diverse arsenal of dozens of closely related proteins from several classes to modulate the immune system’s response. Among these are chemokine-binding proteins, complement pathways inhibitors, ion channels modulators, and numerous poorly characterized proteins whose functions are yet to be uncovered. Studying tick immunomodulatory proteins would not only help to elucidate tick-host relationships but would also provide a rich pool of potential candidates for the development of immunomodulatory intervention drugs and potentially new vaccines. In the present review, we will attempt to summarize novel findings on the salivary immunomodulatory proteins of ticks, focusing on biomolecular targets, structure-activity relationships, and the perspective of their development into therapeutics.
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Affiliation(s)
- Stepan S Denisov
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, Netherlands
| | - Ingrid Dijkgraaf
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, Netherlands
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8
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Ofir-Birin Y, Ben Ami Pilo H, Cruz Camacho A, Rudik A, Rivkin A, Revach OY, Nir N, Block Tamin T, Abou Karam P, Kiper E, Peleg Y, Nevo R, Solomon A, Havkin-Solomon T, Rojas A, Rotkopf R, Porat Z, Avni D, Schwartz E, Zillinger T, Hartmann G, Di Pizio A, Quashie NB, Dikstein R, Gerlic M, Torrecilhas AC, Levy C, Nolte-'t Hoen ENM, Bowie AG, Regev-Rudzki N. Malaria parasites both repress host CXCL10 and use it as a cue for growth acceleration. Nat Commun 2021; 12:4851. [PMID: 34381047 PMCID: PMC8357946 DOI: 10.1038/s41467-021-24997-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 07/14/2021] [Indexed: 12/18/2022] Open
Abstract
Pathogens are thought to use host molecular cues to control when to initiate life-cycle transitions, but these signals are mostly unknown, particularly for the parasitic disease malaria caused by Plasmodium falciparum. The chemokine CXCL10 is present at high levels in fatal cases of cerebral malaria patients, but is reduced in patients who survive and do not have complications. Here we show a Pf 'decision-sensing-system' controlled by CXCL10 concentration. High CXCL10 expression prompts P. falciparum to initiate a survival strategy via growth acceleration. Remarkably, P. falciparum inhibits CXCL10 synthesis in monocytes by disrupting the association of host ribosomes with CXCL10 transcripts. The underlying inhibition cascade involves RNA cargo delivery into monocytes that triggers RIG-I, which leads to HUR1 binding to an AU-rich domain of the CXCL10 3'UTR. These data indicate that when the parasite can no longer keep CXCL10 at low levels, it can exploit the chemokine as a cue to shift tactics and escape.
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Affiliation(s)
- Yifat Ofir-Birin
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Hila Ben Ami Pilo
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Abel Cruz Camacho
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ariel Rudik
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Anna Rivkin
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Or-Yam Revach
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Netta Nir
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tal Block Tamin
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Paula Abou Karam
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Edo Kiper
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yoav Peleg
- Structural Proteomics Unit, Department of Life Sciences Core Facilities (LSCF), Weizmann Institute of Science, Rehovot, Israel
| | - Reinat Nevo
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Aryeh Solomon
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Tal Havkin-Solomon
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alicia Rojas
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Rotkopf
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Ziv Porat
- Flow Cytometry Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Dror Avni
- The Institute of Geographic Medicine and Tropical Diseases and the Laboratory for Tropical Diseases Research, Sheba Medical Center, Ramat Gan, Israel
- Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eli Schwartz
- The Institute of Geographic Medicine and Tropical Diseases and the Laboratory for Tropical Diseases Research, Sheba Medical Center, Ramat Gan, Israel
- Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Thomas Zillinger
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Gunther Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany
| | - Antonella Di Pizio
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Technical University of Munich, Freising, Germany
| | - Neils Ben Quashie
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
- Centre for Tropical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana
| | - Rivka Dikstein
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Motti Gerlic
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ana Claudia Torrecilhas
- Department of Pharmaceutical Sciences, Federal University of São Paulo, UNIFESP, Diadema, Brazil
| | - Carmit Levy
- Department of Human Genetics and Biochemistry, Tel Aviv University, Tel Aviv, Israel
| | - Esther N M Nolte-'t Hoen
- Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Andrew G Bowie
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Neta Regev-Rudzki
- Faculty of Biochemistry, Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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9
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Denisov SS, Ippel JH, Castoldi E, Mans BJ, Hackeng TM, Dijkgraaf I. Molecular basis of anticoagulant and anticomplement activity of the tick salivary protein Salp14 and its homologs. J Biol Chem 2021; 297:100865. [PMID: 34118237 PMCID: PMC8294578 DOI: 10.1016/j.jbc.2021.100865] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
During feeding, a tick's mouthpart penetrates the host's skin and damages tissues and small blood vessels, triggering the extrinsic coagulation and lectin complement pathways. To elude these defense mechanisms, ticks secrete multiple anticoagulant proteins and complement system inhibitors in their saliva. Here, we characterized the inhibitory activities of the homologous tick salivary proteins tick salivary lectin pathway inhibitor, Salp14, and Salp9Pac from Ixodesscapularis in the coagulation cascade and the lectin complement pathway. All three proteins inhibited binding of mannan-binding lectin to the polysaccharide mannan, preventing the activation of the lectin complement pathway. In contrast, only Salp14 showed an appreciable effect on coagulation by prolonging the lag time of thrombin generation. We found that the anticoagulant properties of Salp14 are governed by its basic tail region, which resembles the C terminus of tissue factor pathway inhibitor alpha and blocks the assembly and/or activity of the prothrombinase complex in the same way. Moreover, the Salp14 protein tail contributes to the inhibition of the lectin complement pathway via interaction with mannan binding lectin-associated serine proteases. Furthermore, we identified BaSO4-adsorbing protein 1 isolated from the tick Ornithodoros savignyi as a distant homolog of tick salivary lectin pathway inhibitor/Salp14 proteins and showed that it inhibits the lectin complement pathway but not coagulation. The structure of BaSO4-adsorbing protein 1, solved here using NMR spectroscopy, indicated that this protein adopts a noncanonical epidermal growth factor domain-like structural fold, the first such report for tick salivary proteins. These data support a mechanism by which tick saliva proteins simultaneously inhibit both the host coagulation cascade and the lectin complement pathway.
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Affiliation(s)
- Stepan S Denisov
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands
| | - Johannes H Ippel
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands
| | - Elisabetta Castoldi
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands
| | - Ben J Mans
- Epidemiology, Parasites and Vectors, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort, South Africa; Department of Life and Consumer Sciences, University of South Africa, Pretoria, South Africa; Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Tilman M Hackeng
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands
| | - Ingrid Dijkgraaf
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands.
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10
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Narasimhan S, Kurokawa C, DeBlasio M, Matias J, Sajid A, Pal U, Lynn G, Fikrig E. Acquired tick resistance: The trail is hot. Parasite Immunol 2020; 43:e12808. [PMID: 33187012 DOI: 10.1111/pim.12808] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
Acquired tick resistance is a phenomenon wherein the host elicits an immune response against tick salivary components upon repeated tick infestations. The immune responses, potentially directed against critical salivary components, thwart tick feeding, and the animal becomes resistant to subsequent tick infestations. The development of tick resistance is frequently observed when ticks feed on non-natural hosts, but not on natural hosts. The molecular mechanisms that lead to the development of tick resistance are not fully understood, and both host and tick factors are invoked in this phenomenon. Advances in molecular tools to address the host and the tick are beginning to reveal new insights into this phenomenon and to uncover a deeper understanding of the fundamental biology of tick-host interactions. This review will focus on the expanding understanding of acquired tick resistance and highlight the impact of this understanding on anti-tick vaccine development efforts.
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Affiliation(s)
- Sukanya Narasimhan
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Cheyne Kurokawa
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Melody DeBlasio
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Jaqueline Matias
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Andaleeb Sajid
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Geoffrey Lynn
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
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11
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Denisov SS, Ramírez-Escudero M, Heinzmann ACA, Ippel JH, Dawson PE, Koenen RR, Hackeng TM, Janssen BJC, Dijkgraaf I. Structural characterization of anti-CCL5 activity of the tick salivary protein evasin-4. J Biol Chem 2020; 295:14367-14378. [PMID: 32817341 PMCID: PMC7573271 DOI: 10.1074/jbc.ra120.013891] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/13/2020] [Indexed: 01/30/2023] Open
Abstract
Ticks, as blood-sucking parasites, have developed a complex strategy to evade and suppress host immune responses during feeding. The crucial part of this strategy is expression of a broad family of salivary proteins, called Evasins, to neutralize chemokines responsible for cell trafficking and recruitment. However, structural information about Evasins is still scarce, and little is known about the structural determinants of their binding mechanism to chemokines. Here, we studied the structurally uncharacterized Evasin-4, which neutralizes a broad range of CC-motif chemokines, including the chemokine CC-motif ligand 5 (CCL5) involved in atherogenesis. Crystal structures of Evasin-4 and E66S CCL5, an obligatory dimeric variant of CCL5, were determined to a resolution of 1.3–1.8 Å. The Evasin-4 crystal structure revealed an L-shaped architecture formed by an N- and C-terminal subdomain consisting of eight β-strands and an α-helix that adopts a substantially different position compared with closely related Evasin-1. Further investigation into E66S CCL5–Evasin-4 complex formation with NMR spectroscopy showed that residues of the N terminus are involved in binding to CCL5. The peptide derived from the N-terminal region of Evasin-4 possessed nanomolar affinity to CCL5 and inhibited CCL5 activity in monocyte migration assays. This suggests that Evasin-4 derivatives could be used as a starting point for the development of anti-inflammatory drugs.
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Affiliation(s)
- Stepan S Denisov
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Mercedes Ramírez-Escudero
- Department of Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Alexandra C A Heinzmann
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Johannes H Ippel
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Philip E Dawson
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA
| | - Rory R Koenen
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Tilman M Hackeng
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Bert J C Janssen
- Department of Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ingrid Dijkgraaf
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
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12
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Aounallah H, Bensaoud C, M'ghirbi Y, Faria F, Chmelar JI, Kotsyfakis M. Tick Salivary Compounds for Targeted Immunomodulatory Therapy. Front Immunol 2020; 11:583845. [PMID: 33072132 PMCID: PMC7538779 DOI: 10.3389/fimmu.2020.583845] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022] Open
Abstract
Immunodeficiency disorders and autoimmune diseases are common, but a lack of effective targeted drugs and the side-effects of existing drugs have stimulated interest in finding therapeutic alternatives. Naturally derived substances are a recognized source of novel drugs, and tick saliva is increasingly recognized as a rich source of bioactive molecules with specific functions. Ticks use their saliva to overcome the innate and adaptive host immune systems. Their saliva is a rich cocktail of molecules including proteins, peptides, lipid derivatives, and recently discovered non-coding RNAs that inhibit or modulate vertebrate immune reactions. A number of tick saliva and/or salivary gland molecules have been characterized and shown to be promising candidates for drug development for vertebrate immune diseases. However, further validation of these molecules at the molecular, cellular, and organism levels is now required to progress lead candidates to clinical testing. In this paper, we review the data on the immuno-pharmacological aspects of tick salivary compounds characterized in vitro and/or in vivo and present recent findings on non-coding RNAs that might be exploitable as immunomodulatory therapies.
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Affiliation(s)
- Hajer Aounallah
- Institut Pasteur de Tunis, LR19IPTX, Service d'Entomologie Médicale, Université de Tunis El Manar, Tunis, Tunisia.,Innovation and Development Laboratory, Innovation and Development Center, Instituto Butantan, São Paulo, Brazil
| | - Chaima Bensaoud
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czechia
| | - Youmna M'ghirbi
- Institut Pasteur de Tunis, LR19IPTX, Service d'Entomologie Médicale, Université de Tunis El Manar, Tunis, Tunisia
| | - Fernanda Faria
- Innovation and Development Laboratory, Innovation and Development Center, Instituto Butantan, São Paulo, Brazil
| | - Jindr Ich Chmelar
- Department of Medical Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
| | - Michail Kotsyfakis
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czechia.,Department of Medical Biology, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czechia
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13
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Joshi N, Kumar D, Poluri KM. Elucidating the Molecular Interactions of Chemokine CCL2 Orthologs with Flavonoid Baicalin. ACS OMEGA 2020; 5:22637-22651. [PMID: 32923824 PMCID: PMC7482410 DOI: 10.1021/acsomega.0c03428] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 08/14/2020] [Indexed: 05/03/2023]
Abstract
An integrated and controlled migration of leukocytes is necessary for the legitimate functioning and maintenance of the immune system. Chemokines and their receptors play a decisive role in regulating the leukocyte migration to the site of inflammation, a phenomena often referred to as chemotaxis. Chemokines and their receptors have become significant targets for therapeutic intervention considering their potential to regulate the immune system. Monocyte chemoattractant protein-1 (MCP-1/CCL2) is a preeminent member of CC chemokine family that facilitates crucial roles by orchestrating the recruitment of monocytes into inflamed tissues. Baicalin (BA), a major bioactive flavonoid, has been reported to attenuate chemokine-regulated leukocyte trafficking. However, no molecular details pertaining to its direct binding to chemokine(s)/receptor(s) are available till date. In the current study, using an array of monomers/dimers of human and murine CCL2 orthologs (hCCL2/mCCL2), we have shown that BA binds to the CCL2 protein specifically with nanomolar affinity (K d = 270 ± 20 nM). NMR-based studies established that BA binds CCL2 in a specific pocket involving the N-terminal, β1- and β3-sheets. Docking studies suggested that the residues T16, N17, R18, I20, R24, K49, E50, I51, and C52 are majorly involved in complex formation through a combination of H-bonds and hydrophobic interactions. As the residues R18, R24, and K49 of hCCL2 are crucial determinants of monocyte trafficking through receptor/glycosaminoglycans (GAG) binding in CCL2 human/murine orthologs, we propose that baicalin engaging these residues in complex formation will result in attenuation of CCL2 binding to the receptor/GAGs, thus inhibiting the chemokine-regulated leukocyte trafficking.
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Affiliation(s)
- Nidhi Joshi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Dinesh Kumar
- Centre
of Biomedical Research, SGPGIMS Campus, Lucknow 226014, Uttar Pradesh, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
- , . Tel: +91-1332-284779
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14
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Crijns H, Vanheule V, Proost P. Targeting Chemokine-Glycosaminoglycan Interactions to Inhibit Inflammation. Front Immunol 2020; 11:483. [PMID: 32296423 PMCID: PMC7138053 DOI: 10.3389/fimmu.2020.00483] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Leukocyte migration into tissues depends on the activity of chemokines that form concentration gradients to guide leukocytes to a specific site. Interaction of chemokines with their specific G protein-coupled receptors (GPCRs) on leukocytes induces leukocyte adhesion to the endothelial cells, followed by extravasation of the leukocytes and subsequent directed migration along the chemotactic gradient. Interaction of chemokines with glycosaminoglycans (GAGs) is crucial for extravasation in vivo. Chemokines need to interact with GAGs on endothelial cells and in the extracellular matrix in tissues in order to be presented on the endothelium of blood vessels and to create a concentration gradient. Local chemokine retention establishes a chemokine gradient and prevents diffusion and degradation. During the last two decades, research aiming at reducing chemokine activity mainly focused on the identification of inhibitors of the interaction between chemokines and their cognate GPCRs. This approach only resulted in limited success. However, an alternative strategy, targeting chemokine-GAG interactions, may be a promising approach to inhibit chemokine activity and inflammation. On this line, proteins derived from viruses and parasites that bind chemokines or GAGs may have the potential to interfere with chemokine-GAG interactions. Alternatively, chemokine mimetics, including truncated chemokines and mutant chemokines, can compete with chemokines for binding to GAGs. Such truncated or mutated chemokines are characterized by a strong binding affinity for GAGs and abrogated binding to their chemokine receptors. Finally, Spiegelmers that mask the GAG-binding site on chemokines, thereby preventing chemokine-GAG interactions, were developed. In this review, the importance of GAGs for chemokine activity in vivo and strategies that could be employed to target chemokine-GAG interactions will be discussed in the context of inflammation.
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Affiliation(s)
- Helena Crijns
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Vincent Vanheule
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
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15
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Denisov SS, Heinzmann ACA, Vajen T, Vries MHM, Megens RTA, Suylen D, Koenen RR, Post MJ, Ippel JH, Hackeng TM, Dijkgraaf I. Tick Saliva Protein Evasin-3 Allows for Visualization of Inflammation in Arteries through Interactions with CXC-Type Chemokines Deposited on Activated Endothelium. Bioconjug Chem 2020; 31:948-955. [PMID: 32077689 PMCID: PMC7086393 DOI: 10.1021/acs.bioconjchem.0c00095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Atherosclerosis
is one of the leading causes of mortality in developed
and developing countries. The onset of atherosclerosis development
is accompanied by overexpression of several inflammatory chemokines.
Neutralization of these chemokines by chemokine-binding agents attenuates
atherosclerosis progression. Here, we studied structural binding features
of the tick protein Evasin-3 to chemokine (C-X-C motif) ligand 1 (CXCL1). We showed that Evasin-3-bound CXCL1 is unable to
activate the CXCR2 receptor, but retains affinity to glycosaminoglycans.
This observation was exploited to detect inflammation by visualizing
a group of closely related CXC-type chemokines deposited on cell walls
in human endothelial cells and murine carotid arteries by a fluorescent
Evasin-3 conjugate. This work highlights the applicability of tick-derived
chemokine-binding conjugates as a platform for the development of
new agents for inflammation imaging.
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Affiliation(s)
| | | | | | | | - Remco T A Megens
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Pettenkoferstraße 8a, 80336, Munich, Germany
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16
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Bhattacharya S, Kawamura A. Using evasins to target the chemokine network in inflammation. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 119:1-38. [PMID: 31997766 DOI: 10.1016/bs.apcsb.2019.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inflammation, is driven by a network comprising cytokines, chemokines, their target receptors and leukocytes, and is a major pathologic mechanism that adversely affects organ function in diverse human diseases. Despite being supported by substantial target validation, no successful anti-chemokine therapeutic to treat inflammatory disease has yet been developed. This is in part because of the robustness of the chemokine network, which emerges from a large total chemokine load in disease, promiscuous expression of receptors on leukocytes, promiscuous and synergistic interactions between chemokines and receptors, and feedforward loops created by secretion of chemokines by leukocytes themselves. Many parasites, including viruses, helminths and ticks, evade the chemokine network by producing proteins that bind promiscuously to chemokines or their receptors. Evasins - three small glycoproteins identified in the saliva of the brown dog tick - bind multiple chemokines, and are active in several animal models of inflammatory disease. Over 50 evasin homologs have recently been identified from diverse tick species. Characterization of the chemokine binding patterns of evasins show that several have anti-chemokine activities that extend substantially beyond those previously described. These studies indicate that evasins function at the site of the tick bite by reducing total chemokine load. This not only reduces chemokine signaling to receptors, but also interrupts feedforward loops, thus disabling the chemokine network. Taking the lead from nature, a goal for the development of new anti-chemokine therapeutics would be to reduce the total chemokine load in disease. This could be achieved by administering appropriate evasin combinations or by smaller peptides that mimic evasin action.
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Affiliation(s)
- Shoumo Bhattacharya
- RDM Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
| | - Akane Kawamura
- RDM Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
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17
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Bhusal RP, Eaton JRO, Chowdhury ST, Power CA, Proudfoot AEI, Stone MJ, Bhattacharya S. Evasins: Tick Salivary Proteins that Inhibit Mammalian Chemokines. Trends Biochem Sci 2019; 45:108-122. [PMID: 31679840 PMCID: PMC7322545 DOI: 10.1016/j.tibs.2019.10.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 01/27/2023]
Abstract
Ticks are hematophagous arachnids that parasitize mammals and other hosts, feeding on their blood. Ticks secrete numerous salivary factors that enhance host blood flow or suppress the host inflammatory response. The recruitment of leukocytes, a hallmark of inflammation, is regulated by chemokines, which activate chemokine receptors on the leukocytes. Ticks target this process by secreting glycoproteins called Evasins, which bind to chemokines and prevent leukocyte recruitment. This review describes the recent discovery of numerous Evasins produced by ticks, their classification into two structural and functional classes, and the efficacy of Evasins in animal models of inflammatory diseases. The review also proposes a standard nomenclature system for Evasins and discusses the potential of repurposing or engineering Evasins as therapeutic anti-inflammatory agents.
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Affiliation(s)
- Ram Prasad Bhusal
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - James R O Eaton
- Radcliffe Department of Medicine (RDM) Division of Cardiovascular Medicine and Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Sayeeda T Chowdhury
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Christine A Power
- Biopharm Discovery, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | | | - Martin J Stone
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia.
| | - Shoumo Bhattacharya
- Radcliffe Department of Medicine (RDM) Division of Cardiovascular Medicine and Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.
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