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Ixodes ricinus salivary serpin IRS-2 affects Th17 differentiation via inhibition of the interleukin-6/STAT-3 signaling pathway. Infect Immun 2015; 83:1949-56. [PMID: 25712932 DOI: 10.1128/iai.03065-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/20/2015] [Indexed: 01/10/2023] Open
Abstract
Th17 cells constitute a subset of CD4(+) T lymphocytes that play a crucial role in protection against extracellular bacteria and fungi. They are also associated with tissue injury in autoimmune and inflammatory diseases. Here, we report that serpin from the tick Ixodes ricinus, IRS-2, inhibits Th17 differentiation by impairment of the interleukin-6 (IL-6)/STAT-3 signaling pathway. Following activation, mature dendritic cells produce an array of cytokines, including the pleiotropic cytokine IL-6, which triggers the IL-6 signaling pathway. The major transcription factor activated by IL-6 is STAT-3. We show that IRS-2 selectively inhibits production of IL-6 in dendritic cells stimulated with Borrelia spirochetes, which leads to attenuated STAT-3 phosphorylation and finally to impaired Th17 differentiation. The results presented extend the knowledge about the effect of tick salivary serpins on innate immunity cells and their function in driving adaptive immune responses.
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Hatta T, Miyoshi T, Matsubayashi M, Islam MK, Alim MA, Anas MA, Hasan MM, Matsumoto Y, Yamamoto Y, Yamamoto H, Fujisaki K, Tsuji N. Longistatin in tick saliva blocks advanced glycation end-product receptor activation. J Clin Invest 2015; 124:4429-44. [PMID: 25401185 DOI: 10.1172/jci74917] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ticks are notorious hematophagous ectoparasites and vectors of many deadly pathogens. As an effective vector, ticks must break the strong barrier provided by the skin of their host during feeding, and their saliva contains a complex mixture of bioactive molecules that paralyze host defenses. The receptor for advanced glycation end products (RAGE) mediates immune cell activation at inflammatory sites and is constitutively and highly expressed in skin. Here, we demonstrate that longistatin secreted with saliva of the tick Haemaphysalis longicornis binds RAGE and modulates the host immune response. Similar to other RAGE ligands, longistatin specifically bound the RAGE V domain, and stimulated cultured HUVECs adhered to a longistatin-coated surface; this binding was dramatically inhibited by soluble RAGE or RAGE siRNA. Treatment of HUVECs with longistatin prior to stimulation substantially attenuated cellular oxidative stress and prevented NF-κB translocation, thereby reducing adhesion molecule and cytokine production. Recombinant longistatin inhibited RAGE-mediated migration of mouse peritoneal resident cells (mPRCs) and ameliorated inflammation in mouse footpad edema and pneumonia models. Importantly, tick bite upregulated RAGE ligands in skin, and endogenous longistatin attenuated RAGE-mediated inflammation during tick feeding. Our results suggest that longistatin is a RAGE antagonist that suppresses tick bite-associated inflammation, allowing successful blood-meal acquisition from hosts.
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Rodriguez-Valle M, Xu T, Kurscheid S, Lew-Tabor AE. Rhipicephalus microplus serine protease inhibitor family: annotation, expression and functional characterisation assessment. Parasit Vectors 2015; 8:7. [PMID: 25564202 PMCID: PMC4322644 DOI: 10.1186/s13071-014-0605-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/14/2014] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Rhipicephalus (Boophilus) microplus evades the host's haemostatic system through a complex protein array secreted into tick saliva. Serine protease inhibitors (serpins) conform an important component of saliva which are represented by a large protease inhibitor family in Ixodidae. These secreted and non-secreted inhibitors modulate diverse and essential proteases involved in different physiological processes. METHODS The identification of R. microplus serpin sequences was performed through a web-based bioinformatics environment called Yabi. The database search was conducted on BmiGi V1, BmiGi V2.1, five SSH libraries, Australian tick transcriptome libraries and RmiTR V1 using bioinformatics methods. Semi quantitative PCR was carried out using different adult tissues and tick development stages. The cDNA of four identified R. microplus serpins were cloned and expressed in Pichia pastoris in order to determine biological targets of these serpins utilising protease inhibition assays. RESULTS A total of four out of twenty-two serpins identified in our analysis are new R. microplus serpins which were named as RmS-19 to RmS-22. The analyses of DNA and predicted amino acid sequences showed high conservation of the R. microplus serpin sequences. The expression data suggested ubiquitous expression of RmS except for RmS-6 and RmS-14 that were expressed only in nymphs and adult female ovaries, respectively. RmS-19, and -20 were expressed in all tissues samples analysed showing their important role in both parasitic and non-parasitic stages of R. microplus development. RmS-21 was not detected in ovaries and RmS-22 was not identified in ovary and nymph samples but were expressed in the rest of the samples analysed. A total of four expressed recombinant serpins showed protease specific inhibition for Chymotrypsin (RmS-1 and RmS-6), Chymotrypsin / Elastase (RmS-3) and Thrombin (RmS-15). CONCLUSION This study constitutes an important contribution and improvement to the knowledge about the physiologic role of R. microplus serpins during the host-tick interaction.
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Affiliation(s)
- Manuel Rodriguez-Valle
- The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, Queensland Biosciences Precinct, 306 Carmody Rd, St. Lucia Qld, 4072, Australia.
| | - Tao Xu
- The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, Queensland Biosciences Precinct, 306 Carmody Rd, St. Lucia Qld, 4072, Australia.
| | | | - Ala E Lew-Tabor
- The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, Queensland Biosciences Precinct, 306 Carmody Rd, St. Lucia Qld, 4072, Australia. .,Murdoch University, Centre for Comparative Genomics, Perth, Western Australia, 6150, Australia.
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Porter L, Radulović Ž, Kim T, Braz GRC, Da Silva Vaz I, Mulenga A. Bioinformatic analyses of male and female Amblyomma americanum tick expressed serine protease inhibitors (serpins). Ticks Tick Borne Dis 2014; 6:16-30. [PMID: 25238688 DOI: 10.1016/j.ttbdis.2014.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/20/2014] [Accepted: 08/28/2014] [Indexed: 12/31/2022]
Abstract
Serine protease inhibitors (serpins) are a diverse family of proteins that is conserved across taxa. The diversity of Amblyomma americanum serpins (AAS) is far more complex than previously thought as revealed by discovery of 57 and 33 AAS transcripts that are respectively expressed in male and female A. americanum ticks, with 30 found in both. While distinct reproductively, both male and female metastriate ticks, such as A. americanum, require a blood meal. Thus, 30 AAS sequences found in both male and female ticks could play important role(s) in regulating tick feeding and thus represent attractive candidates for anti-tick vaccine development. Of significant interest, 19 AAS sequences expressed in male and female ticks are also part of the 48 AAS sequences expressed in fed female tick salivary glands or midguts; two organs through which the tick interacts with host blood and immune response factors. Considered the most important domain for serpin function, the reactive center loop (RCL) is further characterized by a single 'P1' site amino acid residue, which is central to determining the protease regulated by the serpin. In this study, a diversity of 17 different P1 site amino acid residues were predicted, suggesting that A. americanum serpins potentially regulate a large number of proteolytic pathways. Our data also indicate that some serpins in this study could regulate target protease common to all tick species, in that more than 40% of AAS show 58-97% inter-species amino acid conservation. Of significance, 24% of AAS showed 62-100% inter-species conservation within the functional RCL domain, with 10 RCLs showing ≥90-100% conservation. In vertebrates, serpins with basic residues at the P1 site regulate key host defense pathways, which the tick must evade to feed successfully. Interestingly, we found that AAS sequences with basic or polar uncharged residues at the putative P1 site are more likely to be conserved across tick species. Another notable observation from our data is that AAS sequences found only in female ticks and those found in both males and females, but not those found only in male ticks, were highly conserved in other tick species. While descriptive, this study provides the basis for more in-depth studies exploring the roles of serpins in tick feeding physiology.
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Affiliation(s)
- Lindsay Porter
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, United States
| | - Željko Radulović
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, United States
| | - Tae Kim
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, United States
| | - Gloria R C Braz
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro - UFRJ, Rio de Janeiro, Brazil
| | - Itabajara Da Silva Vaz
- Centro de Biotecnologia and Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil
| | - Albert Mulenga
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, United States.
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Garcia GR, Gardinassi LG, Ribeiro JM, Anatriello E, Ferreira BR, Moreira HNS, Mafra C, Martins MM, Szabó MPJ, de Miranda-Santos IKF, Maruyama SR. The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq. Parasit Vectors 2014; 7:430. [PMID: 25201527 PMCID: PMC4261526 DOI: 10.1186/1756-3305-7-430] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/22/2014] [Indexed: 12/19/2022] Open
Abstract
Background Tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interactions, and transcriptional profiling of salivary glands is a powerful tool to do so. Here, we functionally annotated the sialotranscriptomes of these three Amblyomma species, which allowed comparisons between these and other hematophagous arthropod species. Methods mRNA from the salivary glands of A. triste, A. cajennense and A. parvum ticks fed on different host species were pyrosequenced on a 454-Roche platform to generate four A. triste (nymphs fed on guinea pigs and females fed on dogs) libraries, one A. cajennense (females fed on rabbits) library and one was A. parvum (females fed on dogs) library. Bioinformatic analyses used in-house programs with a customized pipeline employing standard assembly and alignment algorithms, protein databases and protein servers. Results Each library yielded an average of 100,000 reads, which were assembled to obtain contigs of coding sequences (CDSs). The sialotranscriptome analyses of A. triste, A. cajennense and A. parvum ticks produced 11,240, 4,604 and 3,796 CDSs, respectively. These CDSs were classified into over 100 distinct protein families with a wide range of putative functions involved in physiological and blood feeding processes and were catalogued in annotated, hyperlinked spreadsheets. We highlighted the putative transcripts encoding saliva components with critical roles during parasitism, such as anticoagulants, immunosuppressants and anti-inflammatory molecules. The salivary content underwent changes in the abundance and repertoire of many transcripts, which depended on the tick and host species. Conclusions The annotated sialotranscriptomes described herein richly expand the biological knowledge of these three Amblyomma species. These comprehensive databases will be useful for the characterization of salivary proteins and can be applied to control ticks and tick-borne diseases. Electronic supplementary material The online version of this article (doi:10.1186/1756-3305-7-430) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Sandra Regina Maruyama
- Department of Biochemistry and Immunology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Functional characterization of SjB10, an intracellular serpin from Schistosoma japonicum. Parasitology 2014; 141:1746-60. [PMID: 25137634 DOI: 10.1017/s0031182014001061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Serine protease inhibitors (serpin) play essential roles in many organisms. Mammalian serpins regulate the blood coagulation, fibrinolysis, inflammation and complement activation pathways. In parasitic helminths, serpins are less well characterized, but may also be involved in evasion of the host immune response. In this study, a Schistosoma japonicum serpin (SjB10), containing a 1212 bp open reading frame (ORF), was cloned, expressed and functionally characterized. Sequence analysis, comparative modelling and structural-based alignment revealed that SjB10 contains the essential structural motifs and consensus secondary structures of inhibitory serpins. Transcriptional profiling demonstrated that SjB10 is expressed in adult males, schistosomula and eggs but particularly in the cercariae, suggesting a possible role in cercarial penetration of mammalian host skin. Recombinant SjB10 (rSjB10) inhibited pancreatic elastase (PE) in a dose-dependent manner. rSjB10 was recognized strongly by experimentally infected rat sera indicating that native SjB10 is released into host tissue and induces an immune response. By immunochemistry, SjB10 localized in the S. japonicum adult foregut and extra-embryonic layer of the egg. This study provides a comprehensive demonstration of sequence and structural-based analysis of a functional S. japonicum serpin. Furthermore, our findings suggest that SjB10 may be associated with important functional roles in S. japonicum particularly in host-parasite interactions.
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Molehin AJ, Gobert GN, Driguez P, McManus DP. Characterisation of a secretory serine protease inhibitor (SjB6) from Schistosoma japonicum. Parasit Vectors 2014; 7:330. [PMID: 25023829 PMCID: PMC4223420 DOI: 10.1186/1756-3305-7-330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/07/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Proteins belonging to the serine protease inhibitor (serpin) superfamily play essential physiological roles in many organisms. In pathogens, serpins are thought to have evolved specifically to limit host immune responses by interfering with the host immune-stimulatory signals. Serpins are less well characterised in parasitic helminths, although some are thought to be involved in mechanisms associated with host immune modulation. In this study, we cloned and partially characterised a secretory serpin from Schistosoma japonicum termed SjB6, these findings provide the basis for possible functional roles. METHODS SjB6 gene was identified through database mining of our previously published microarray data, cloned and detailed sequence and structural analysis and comparative modelling carried out using various bioinformatics and proteomics tools. Gene transcriptional profiling was determined by real-time PCR and the expression of native protein determined by immunoblotting. An immunological profile of the recombinant protein produced in insect cells was determined by ELISA. RESULTS SjB6 contains an open reading frame of 1160 base pairs that encodes a protein of 387 amino acid residues. Detailed sequence analysis, comparative modelling and structural-based alignment revealed that SjB6 contains the essential structural motifs and consensus secondary structures typical of inhibitory serpins. The presence of an N-terminal signal sequence indicated that SjB6 is a secretory protein. Real-time data indicated that SjB6 is expressed exclusively in the intra-mammalian stage of the parasite life cycle with its highest expression levels in the egg stage (p < 0.0001). The native protein is approximately 60 kDa in size and recombinant SjB6 (rSjB6) was recognised strongly by sera from rats experimentally infected with S. japonicum. CONCLUSIONS The significantly high expression of SjB6 in schistosome eggs, when compared to other life cycle stages, suggests a possible association with disease pathology, while the strong reactivity of sera from experimentally infected rats against rSjB6 suggests that native SjB6 is released into host tissue and induces an immune response. This study presents a comprehensive demonstration of sequence and structural-based analysis of a secretory serpin from a trematode and suggests SjB6 may be associated with important functional roles in S. japonicum, particularly in parasite modulation of the host microenvironment.
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Affiliation(s)
- Adebayo J Molehin
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston 4006, Australia.
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Tirloni L, Reck J, Terra RMS, Martins JR, Mulenga A, Sherman NE, Fox JW, Yates JR, Termignoni C, Pinto AFM, da Silva Vaz I. Proteomic analysis of cattle tick Rhipicephalus (Boophilus) microplus saliva: a comparison between partially and fully engorged females. PLoS One 2014; 9:e94831. [PMID: 24762651 PMCID: PMC3998978 DOI: 10.1371/journal.pone.0094831] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/19/2014] [Indexed: 01/10/2023] Open
Abstract
The cattle tick Rhipicephalus (Boophilus) microplus is one of the most harmful parasites affecting bovines. Similarly to other hematophagous ectoparasites, R. microplus saliva contains a collection of bioactive compounds that inhibit host defenses against tick feeding activity. Thus, the study of tick salivary components offers opportunities for the development of immunological based tick control methods and medicinal applications. So far, only a few proteins have been identified in cattle tick saliva. The aim of this work was to identify proteins present in R. microplus female tick saliva at different feeding stages. Proteomic analysis of R. microplus saliva allowed identifying peptides corresponding to 187 and 68 tick and bovine proteins, respectively. Our data confirm that (i) R. microplus saliva is complex, and (ii) that there are remarkable differences in saliva composition between partially engorged and fully engorged female ticks. R. microplus saliva is rich mainly in (i) hemelipoproteins and other transporter proteins, (ii) secreted cross-tick species conserved proteins, (iii) lipocalins, (iv) peptidase inhibitors, (v) antimicrobial peptides, (vii) glycine-rich proteins, (viii) housekeeping proteins and (ix) host proteins. This investigation represents the first proteomic study about R. microplus saliva, and reports the most comprehensive Ixodidae tick saliva proteome published to date. Our results improve the understanding of tick salivary modulators of host defense to tick feeding, and provide novel information on the tick-host relationship.
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Affiliation(s)
- Lucas Tirloni
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
| | - José Reck
- Instituto de Pesquisas Veterinárias Desidério Finamor, Fundação Estadual de Pesquisa Agropecuária, Eldorado do Sul, RS, Brazil
| | - Renata Maria Soares Terra
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
- CAPES, Ministério da Educação do Brasil, Brasília, DF, Brasil
| | - João Ricardo Martins
- Instituto de Pesquisas Veterinárias Desidério Finamor, Fundação Estadual de Pesquisa Agropecuária, Eldorado do Sul, RS, Brazil
| | - Albert Mulenga
- Department of Entomology, Texas A&M University, College Station, Texas, United States of America
| | - Nicholas E. Sherman
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jay W. Fox
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - John R. Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Carlos Termignoni
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Antônio F. M. Pinto
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
- CAPES, Ministério da Educação do Brasil, Brasília, DF, Brasil
| | - Itabajara da Silva Vaz
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Ibelli AMG, Kim TK, Hill CC, Lewis LA, Bakshi M, Miller S, Porter L, Mulenga A. A blood meal-induced Ixodes scapularis tick saliva serpin inhibits trypsin and thrombin, and interferes with platelet aggregation and blood clotting. Int J Parasitol 2014; 44:369-79. [PMID: 24583183 DOI: 10.1016/j.ijpara.2014.01.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/29/2013] [Accepted: 01/06/2014] [Indexed: 01/22/2023]
Abstract
Ixodes scapularis is a medically important tick species that transmits causative agents of important human tick-borne diseases including borreliosis, anaplasmosis and babesiosis. An understanding of how this tick feeds is needed prior to the development of novel methods to protect the human population against tick-borne disease infections. This study characterizes a blood meal-induced I. scapularis (Ixsc) tick saliva serine protease inhibitor (serpin (S)), in-house referred to as IxscS-1E1. The hypothesis that ticks use serpins to evade the host's defense response to tick feeding is based on the assumption that tick serpins inhibit functions of protease mediators of the host's anti-tick defense response. Thus, it is significant that consistent with hallmark characteristics of inhibitory serpins, Pichia pastoris-expressed recombinant IxscS-1E1 (rIxscS-1E1) can trap thrombin and trypsin in SDS- and heat-stable complexes, and reduce the activity of the two proteases in a dose-responsive manner. Additionally, rIxscS-1E1 also inhibited, but did not apparently form detectable complexes with, cathepsin G and factor Xa. Our data also show that rIxscS-1E1 may not inhibit chymotrypsin, kallikrein, chymase, plasmin, elastase and papain even at a much higher rIxscS-1E1 concentration. Native IxscS-1E1 potentially plays a role(s) in facilitating I. scapularis tick evasion of the host's hemostatic defense as revealed by the ability of rIxscS-1E1 to inhibit adenosine diphosphate- and thrombin-activated platelet aggregation, and delay activated partial prothrombin time and thrombin time plasma clotting in a dose-responsive manner. We conclude that native IxscS-1E1 is part of the tick saliva protein complex that mediates its anti-hemostatic, and potentially inflammatory, functions by inhibiting the actions of thrombin, trypsin and other yet unknown trypsin-like proteases at the tick-host interface.
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Affiliation(s)
- Adriana M G Ibelli
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA; Federal University of São Carlos, Graduate Program in Genetics and Evolution, Brazil
| | - Tae K Kim
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA
| | - Creston C Hill
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA
| | - Lauren A Lewis
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA
| | - Mariam Bakshi
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA
| | - Stephanie Miller
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA; College Station High School, Science Department-Biology, 4002 Victoria Ave, College Station, TX 77845, USA
| | - Lindsay Porter
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA
| | - Albert Mulenga
- Texas A & M University AgriLife Research, Department of Entomology, 2475 TAMU, College Station, TX 77843, USA.
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Tirloni L, Seixas A, Mulenga A, Vaz IDS, Termignoni C. A family of serine protease inhibitors (serpins) in the cattle tick Rhipicephalus (Boophilus) microplus. Exp Parasitol 2013; 137:25-34. [PMID: 24333790 DOI: 10.1016/j.exppara.2013.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/29/2013] [Accepted: 12/03/2013] [Indexed: 11/30/2022]
Abstract
Proteins belonging to the serine protease inhibitor (serpin) superfamily play essential roles in many organisms. In arthropods these proteins are involved in innate immune system, morphogenesis and development. In mammals serpins regulate pathways that are essential to life such as blood coagulation, fibrinolysis, inflammation and complement activation, some of which are considered the host's first line of defense to hematophagous and/or blood dueling parasites. Thus, it is hypothesized that ticks use serpins to evade host defense, facilitating parasitism. This study describes eighteen full-length cDNA sequences encoding serpins identified in Rhipicephalus (Boophilus) microplus, here named RmS 1-18 (R. microplus serpin). Spatial and temporal transcriptional profiling demonstrated that R. microplus serpins are transcribed during feeding, suggesting their participation in tick physiology regulation. We speculate that the majority of R. microplus serpins are conserved in other ticks, as indicated by phylogeny analysis. Over half of the 18 RmSs are putatively functional in the extracellular environment, as indicated by putative signal peptides on 11 of 18 serpins. Comparative modeling and structural-based alignment revealed that R. microplus serpins in this study retain the consensus secondary of typical serpins. This descriptive study enlarges the knowledge on the molecular biology of R. microplus, an important tick species.
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Affiliation(s)
- Lucas Tirloni
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil
| | - Adriana Seixas
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil; Departamento de Ciências Básicas da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre, Rua Sarmento Leite 245, Porto Alegre 90050-170, RS, Brazil
| | - Albert Mulenga
- Department of Entomology, Texas A&M University, Minnie Heep Center, College Station, TX, USA
| | - Itabajara da Silva Vaz
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil; Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9090, Porto Alegre 91540-000, RS, Brazil.
| | - Carlos Termignoni
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, Prédio 43421, Porto Alegre 91501-970, RS, Brazil; Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, Porto Alegre 90035-000, RS, Brazil
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Kazimírová M, Štibrániová I. Tick salivary compounds: their role in modulation of host defences and pathogen transmission. Front Cell Infect Microbiol 2013; 3:43. [PMID: 23971008 PMCID: PMC3747359 DOI: 10.3389/fcimb.2013.00043] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/26/2013] [Indexed: 01/24/2023] Open
Abstract
Ticks require blood meal to complete development and reproduction. Multifunctional tick salivary glands play a pivotal role in tick feeding and transmission of pathogens. Tick salivary molecules injected into the host modulate host defence responses to the benefit of the feeding ticks. To colonize tick organs, tick-borne microorganisms must overcome several barriers, i.e., tick gut membrane, tick immunity, and moulting. Tick-borne pathogens co-evolved with their vectors and hosts and developed molecular adaptations to avoid adverse effects of tick and host defences. Large gaps exist in the knowledge of survival strategies of tick-borne microorganisms and on the molecular mechanisms of tick-host-pathogen interactions. Prior to transmission to a host, the microorganisms penetrate and multiply in tick salivary glands. As soon as the tick is attached to a host, gene expression and production of salivary molecules is upregulated, primarily to facilitate feeding and avoid tick rejection by the host. Pathogens exploit tick salivary molecules for their survival and multiplication in the vector and transmission to and establishment in the hosts. Promotion of pathogen transmission by bioactive molecules in tick saliva was described as saliva-assisted transmission (SAT). SAT candidates comprise compounds with anti-haemostatic, anti-inflammatory and immunomodulatory functions, but the molecular mechanisms by which they mediate pathogen transmission are largely unknown. To date only a few tick salivary molecules associated with specific pathogen transmission have been identified and their functions partially elucidated. Advanced molecular techniques are applied in studying tick-host-pathogen interactions and provide information on expression of vector and pathogen genes during pathogen acquisition, establishment and transmission. Understanding the molecular events on the tick-host-pathogen interface may lead to development of new strategies to control tick-borne diseases.
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Affiliation(s)
- Mária Kazimírová
- Institute of Zoology, Slovak Academy of Sciences Bratislava, Slovakia.
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Mulenga A, Kim T, Ibelli AMG. Amblyomma americanum tick saliva serine protease inhibitor 6 is a cross-class inhibitor of serine proteases and papain-like cysteine proteases that delays plasma clotting and inhibits platelet aggregation. INSECT MOLECULAR BIOLOGY 2013; 22:306-19. [PMID: 23521000 PMCID: PMC4058330 DOI: 10.1111/imb.12024] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We previously demonstrated that Amblyomma americanum tick serine protease inhibitor 6 (AamS6) was secreted into the host during tick feeding and that both its mRNA and protein were ubiquitously and highly expressed during the first 3 days of tick feeding. This study demonstrates that AamS6 is a cross-class inhibitor of both serine- and papain-like cysteine proteases that has apparent antihaemostatic functions. Consistent with the typical inhibitory serpin characteristics, enzyme kinetics analyses revealed that Pichia pastoris-expressed recombinant (r) AamS6 reduced initial velocities of substrate hydrolysis (V₀) and/or maximum enzyme velocity (V(max)) of trypsin, chymotrypsin, elastase, chymase, and papain in a dose-response manner. We speculate that rAamS6 inhibited plasmin in a temporary fashion in that while rAamS6 reduced V₀ of plasmin by up to ∼53%, it had no effect on V(max). Our data also suggest that rAmS6 has minimal or no apparent effect on V₀ or V(max) of thrombin, factor Xa, and kallikrein. We speculate that AamS6 is apparently involved in facilitating blood meal feeding in that various amounts of rAamS6 reduced platelet aggregation by up to ∼47% and delayed plasma clotting time in the recalcification time assay by up to ∼210 s. AamS6 is most likely not involved with the tick's evasion of the host's complement defense mechanism, in that rAamS6 did not interfere with the complement activation pathway. Findings in this study are discussed in the context of expanding our understanding of tick proteins that control bloodmeal feeding and hence tick-borne disease transmission by ticks.
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Affiliation(s)
- A Mulenga
- Department of Entomology, Texas A & M University AgriLife Research, College Station, TX, USA.
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Yu Y, Cao J, Zhou Y, Zhang H, Zhou J. Isolation and characterization of two novel serpins from the tick Rhipicephalus haemaphysaloides. Ticks Tick Borne Dis 2013; 4:297-303. [PMID: 23601911 DOI: 10.1016/j.ttbdis.2013.02.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/31/2013] [Accepted: 02/03/2013] [Indexed: 12/14/2022]
Abstract
Two novel serpins with anti-chymotrypsin activity, RHS-1 and RHS-2, were identified in the tick Rhipicephalus haemaphysaloides. The complementary cDNA sequence of RHS-1 was 1286 base pairs (bp) and encoded a deduced 403-amino acid protein with a signal peptide, whereas that of RHS-2 was 1682bp and encoded a deduced 380-amino acid protein with no signal peptide. Although both RHS-1 and RHS-2 exhibited high sequence similarities to known serpins from other ticks, the level of similarity at the amino acid level between the 2 serpins characterized here was only 32.5%. Salivary gland-specific expression of RHS-1 and midgut-specific expression of RHS-2 were found by Western blot using the relevant antiserum. We tested the ability of purified recombinant rRHS-1 and rRHS-2 to inhibit various serine proteases and found that both significantly inhibited chymotrypsin (95.6% and 94.2%, respectively). We further demonstrated that RHS-1, but not RHS-2 exhibited anticoagulation activity, based on activated partial thromboplastin time (APTT). Disruption of the genes encoding the 2 serpins with RNA interference (RNAi) led to a significant decrease in tick attachment and engorgement rates. These results indicate that RHS-1 and RHS-2 are 2 novel serpins with anti-chymotrypsin activity that are involved in blood feeding of R. haemaphysaloides.
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Affiliation(s)
- Yingfang Yu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
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Alim MA, Islam MK, Miyoshi T, Hatta T, Yamaji K, Matsubayashi M, Fujisaki K, Tsuji N. A hemocyte-derived Kunitz-BPTI-type chymotrypsin inhibitor, HlChI, from the ixodid tick Haemaphysalis longicornis, plays regulatory functions in tick blood-feeding processes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:925-934. [PMID: 23017545 DOI: 10.1016/j.ibmb.2012.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 08/10/2012] [Accepted: 09/16/2012] [Indexed: 06/01/2023]
Abstract
Inhibitors of proteases play key roles in the biological processes of vertebrate and invertebrate animals, including arthropod parasites. Here, we describe a cDNA that encodes a functionally active chymotrypsin inhibitor of the BPTI/Kunitz family of serine protease inhibitors from the hemocytes of the ixodid tick, Haemaphysalis longicornis, herein called HlChI. HlChI sequence is evolutionarily conserved and contains six cysteine residues and three disulfide bonds with a calculated molecular weight of 9.1 kDa. HlChI-specific mRNA was expressed in all developmental stages of ticks and the expression was up-regulated by host's blood-feeding processes. Endogenous HlChI was localized mainly in the hemocytes. HlChI potently inhibited bovine pancreatic α-chymotrypsin for hydrolyzing the fluorogenic substrate (IC(50) 8.32 nM, K(d) 5.35 ± 1.01 nM) and bovine casein digestion. However, HlChI weakly inhibited bovine pancreatic trypsin and could not affect the porcine elastase activity, suggesting its narrow specificity to chymotrypsin. HlChI was stable over the pH range 2-11 and heating up to 70 °C at pH 8. HlChI was highly stable to 8 M urea and 2% SDS at pH 8.0, when treated for 24 h at 37 °C. However, 0.2 M 2-mercaptoethanol caused complete but reversible inactivation of HlChI. Knockdown of HlChI gene by RNA interference (RNAi) caused death of the feeding ticks, failure of ticks to engorge and significantly reduced body weight gain. RNAi also resulted in significantly decreased egg conversion ratio and fecundity. These results suggest that HlChI is a chymotrypsin-specific inhibitor with high stability and may play regulatory functions in host's blood-feeding processes and tick reproduction.
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Affiliation(s)
- M Abdul Alim
- Laboratory of Parasitic Diseases, National Institute of Animal Health, National Agricultural and Food Research Organization, Tsukuba, Ibaraki 305-0856, Japan
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Chmelar J, Calvo E, Pedra JHF, Francischetti IMB, Kotsyfakis M. Tick salivary secretion as a source of antihemostatics. J Proteomics 2012; 75:3842-54. [PMID: 22564820 DOI: 10.1016/j.jprot.2012.04.026] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/13/2012] [Accepted: 04/18/2012] [Indexed: 01/04/2023]
Abstract
Ticks are mostly obligatory blood feeding ectoparasites that have an impact on human and animal health. In addition to direct damage due to feeding, some tick species serve as the vectors for the causative agents of several diseases, such as the spirochetes of the genus Borrelia causing Lyme disease, the virus of tick-borne encephalitis, various Rickettsial pathogens or even protozoan parasites like Babesia spp. Hard ticks are unique among bloodfeeders because of their prolonged feeding period that may last up to two weeks. During such a long period of blood uptake, the host develops a wide range of mechanisms to prevent blood loss. The arthropod ectoparasite, in turn, secretes saliva in the sites of bite that assists blood feeding. Indeed, tick saliva represents a rich source of proteins with potent pharmacologic action that target different mechanisms of coagulation, platelet aggregation and vasoconstriction. Tick adaptation to their vertebrate hosts led to the inclusion of a powerful protein armamentarium in their salivary secretion that has been investigated by high-throughput methods. The resulting knowledge can be exploited for the isolation of novel antihemostatic agents. Here we review the tick salivary antihemostatics and their characterized functions at the molecular and cellular levels.
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Affiliation(s)
- Jindrich Chmelar
- Division of Vascular Inflammation, Diabetes and Kidney, Department of Medicine and Institute of Physiology, Technical University Dresden, 01307 Dresden, Germany
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Abstract
Serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified in Ascaris spp., Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosoma spp., Clonorchis sinensis, Paragonimus westermani and Echinococcus spp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships.
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Guerrero B, Arocha-Piñango CL, Salazar AM, Gil A, Sánchez EE, Rodríguez-Acosta A, Lucena S. The effects of Lonomin V, a toxin from the caterpillar (Lonomia achelous), on hemostasis parameters as measured by platelet function. Toxicon 2011; 58:293-303. [PMID: 21820001 DOI: 10.1016/j.toxicon.2011.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 04/15/2011] [Accepted: 07/12/2011] [Indexed: 11/30/2022]
Abstract
Platelets play a central role in hemostasis during vascular injury. Patients affected with the hemorrhagic syndrome caused by contact with Lonomia achelous caterpillars (Lac) Lepidoptera distributed in various South American countries, show digestive, pulmonary and intraperitoneal bleeding in combination with hematomas and echymosis. In the present study, we have evaluated the effects of Lonomin V (serine protease isolated from Lac hemolymph) on some functional properties of platelets, evaluating its importance in primary hemostasis. Platelet adhesion to fibrinogen was reduced by 19, 20, 36, and 37% after pre-treated with 0.2, 2, 20 and 40 nM of Lonomin V, respectively. Pre-incubation of the platelets with 408 nM of Lonomin V, for 4 min at 37 °C, resulted in complete inhibition of the collagen-induced platelet aggregation, in contrast to 56% inhibition of the ADP - induced platelet aggregation. Lonomin V also inhibited anti-α(IIb)β(3) integrin binding to platelets by 56, 57, 52 and 54% at concentrations of 0.2, 2, 20 and 40 nM respectively. Additionally, Lonomin V inhibited anti-P-selectin binding to platelets by 28, 37, 33 and 33% at the same concentrations. The platelets tested with Lonomin V did not modify their viability. In summary, Lonomin V inhibited platelet aggregation, probably caused by the degradation of collagen. The anti-platelet activity of Lonomin V has been shown to be unique and a potentially useful tool for investigating cell-matrix and cell-cell interactions and for the development of antithrombotic agents in terms of their anti-adhesive activities.
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Affiliation(s)
- Belsy Guerrero
- Laboratorio de Fisiopatología, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, Caracas 1020A, Republic of Venezuela
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68
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Prevention of Lyme Disease: Promising Research or Sisyphean Task? Arch Immunol Ther Exp (Warsz) 2011; 59:261-75. [DOI: 10.1007/s00005-011-0128-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/02/2011] [Indexed: 11/26/2022]
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Chalaire KC, Kim TK, Garcia-Rodriguez H, Mulenga A. Amblyomma americanum (L.) (Acari: Ixodidae) tick salivary gland serine protease inhibitor (serpin) 6 is secreted into tick saliva during tick feeding. ACTA ACUST UNITED AC 2011; 214:665-73. [PMID: 21270316 DOI: 10.1242/jeb.052076] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In order to successfully feed and transmit disease agents, ticks are thought to inject serine protease inhibitors (serpins) into the host to modulate host defense responses to tick feeding, such as inflammation, the complement activation pathway and blood coagulation. In this study, we show that Amblyomma americanum (Aam) serpin (S) 6 is putatively injected into the host during tick feeding, in that the antibody to recombinant (r) AamS6 specifically reacted with the expected ∼43/45 kDa AamS6 protein band on western blots of pilocarpine-induced tick saliva. Additionally, antibodies to tick saliva proteins that were generated by repeated 48 h infestations of rabbits with adult A. americanum specifically reacted with rAamS6. We speculate that AamS6 is associated with regulating events at the start of the tick feeding process, as temporal and spatial RT-PCR and western blot analyses revealed that both AamS6 mRNA and protein are strongly expressed during the first 24-72 h of feeding time before starting to fade from 96 h. The AamS6 protein has an apparently slow turnover rate in that, although the injection of AamS6 dsRNA into unfed ticks triggered complete disruption of the AamS6 mRNA by the 48 h feeding time point, western blot analysis of protein extracts of the same animals showed that the AamS6 protein that may have been expressed prior to disruption of the AamS6 mRNA was not depleted. We speculate that the presence of the AamS6 protein in ticks despite the complete disruption of the AamS6 mRNA explains the observation that RNAi-mediated silencing of the AamS6 mRNA did not affect the ability of A. americanum ticks to attach onto host skin, successfully feed and lay eggs. These findings are discussed in regards to advances in the molecular biology of ticks.
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70
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Schuijt TJ, Narasimhan S, Daffre S, DePonte K, Hovius JWR, Van't Veer C, van der Poll T, Bakhtiari K, Meijers JCM, Boder ET, van Dam AP, Fikrig E. Identification and characterization of Ixodes scapularis antigens that elicit tick immunity using yeast surface display. PLoS One 2011; 6:e15926. [PMID: 21246036 PMCID: PMC3016337 DOI: 10.1371/journal.pone.0015926] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/02/2010] [Indexed: 11/30/2022] Open
Abstract
Repeated exposure of rabbits and other animals to ticks results in acquired resistance or immunity to subsequent tick bites and is partially elicited by antibodies directed against tick antigens. In this study we demonstrate the utility of a yeast surface display approach to identify tick salivary antigens that react with tick-immune serum. We constructed an Ixodes scapularis nymphal salivary gland yeast surface display library and screened the library with nymph-immune rabbit sera and identified five salivary antigens. Four of these proteins, designated P8, P19, P23 and P32, had a predicted signal sequence. We generated recombinant (r) P8, P19 and P23 in a Drosophila expression system for functional and immunization studies. rP8 showed anti-complement activity and rP23 demonstrated anti-coagulant activity. Ixodes scapularis feeding was significantly impaired when nymphs were fed on rabbits immunized with a cocktail of rP8, rP19 and rP23, a hall mark of tick-immunity. These studies also suggest that these antigens may serve as potential vaccine candidates to thwart tick feeding.
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Affiliation(s)
- Tim J Schuijt
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America.
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A tick salivary protein targets cathepsin G and chymase and inhibits host inflammation and platelet aggregation. Blood 2010; 117:736-44. [PMID: 20940421 DOI: 10.1182/blood-2010-06-293241] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet aggregation and acute inflammation are key processes in vertebrate defense to a skin injury. Recent studies uncovered the mediation of 2 serine proteases, cathepsin G and chymase, in both mechanisms. Working with a mouse model of acute inflammation, we revealed that an exogenous salivary protein of Ixodes ricinus, the vector of Lyme disease pathogens in Europe, extensively inhibits edema formation and influx of neutrophils in the inflamed tissue. We named this tick salivary gland secreted effector as I ricinus serpin-2 (IRS-2), and we show that it primarily inhibits cathepsin G and chymase, while in higher molar excess, it affects thrombin activity as well. The inhibitory specificity was explained using the crystal structure, determined at a resolution of 1.8 Å. Moreover, we disclosed the ability of IRS-2 to inhibit cathepsin G-induced and thrombin-induced platelet aggregation. For the first time, an ectoparasite protein is shown to exhibit such pharmacological effects and target specificity. The stringent specificity and biological activities of IRS-2 combined with the knowledge of its structure can be the basis for the development of future pharmaceutical applications.
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72
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Schuijt TJ, Hovius JW, van der Poll T, van Dam AP, Fikrig E. Lyme borreliosis vaccination: the facts, the challenge, the future. Trends Parasitol 2010; 27:40-7. [PMID: 20594913 DOI: 10.1016/j.pt.2010.06.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Revised: 05/31/2010] [Accepted: 06/02/2010] [Indexed: 11/26/2022]
Abstract
Lyme disease, or Lyme borreliosis, the most prevalent arthropod-borne disease in the Western world, is caused by spirochetes belonging to the Borrelia burgdorferi sensu lato group and is predominantly transmitted through Ixodes ticks. There is currently no vaccine available to prevent Lyme borreliosis in humans. Borrelia outer membrane proteins are reviewed which have been investigated as vaccine candidates. In addition, several tick proteins are discussed, on which anti-tick vaccines have been based, or are interesting future candidates, to prevent transmission of the spirochete from the tick vector to the mammalian host. Finally, novel vaccination strategies to prevent Lyme borreliosis are proposed, based on multiple Borrelia antigens, tick antigens or a combination of both Borrelia as well as tick antigens.
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Affiliation(s)
- T J Schuijt
- Academic Medical Center, University of Amsterdam, Center for Experimental and Molecular Medicine, Amsterdam, The Netherlands
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73
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Venom proteins of the parasitoid wasp Nasonia vitripennis: recent discovery of an untapped pharmacopee. Toxins (Basel) 2010; 2:494-516. [PMID: 22069597 PMCID: PMC3153221 DOI: 10.3390/toxins2040494] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 03/22/2010] [Accepted: 03/24/2010] [Indexed: 01/08/2023] Open
Abstract
Adult females of Nasonia vitripennis inject a venomous mixture into its host flies prior to oviposition. Recently, the entire genome of this ectoparasitoid wasp was sequenced, enabling the identification of 79 venom proteins. The next challenge will be to unravel their specific functions, but based on homolog studies, some predictions already can be made. Parasitization has an enormous impact on hosts physiology of which five major effects are discussed in this review: the impact on immune responses, induction of developmental arrest, increases in lipid levels, apoptosis and nutrient releases. The value of deciphering this venom is also discussed.
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A repertoire of the dominant transcripts from the salivary glands of the blood-sucking bug, Triatoma dimidiata, a vector of Chagas disease. INFECTION GENETICS AND EVOLUTION 2009; 10:184-91. [PMID: 19900580 DOI: 10.1016/j.meegid.2009.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 10/10/2009] [Accepted: 10/31/2009] [Indexed: 11/27/2022]
Abstract
Triatoma (T.) dimidiata is a hematophagous Hemiptera and a main vector of Chagas disease. The saliva of this and other blood-sucking insects contains potent pharmacologically active components that assist them in counteracting the host hemostatic and inflammatory systems during blood feeding. To describe the repertoire of potential bioactive salivary molecules from this insect, a number of randomly selected transcripts from the salivary gland cDNA library of T. dimidiata were sequenced and analyzed. This analysis showed that 77.5% of the isolated transcripts coded for putative secreted proteins, and 89.9% of these coded for variants of the lipocalin family proteins. The most abundant transcript was a homologue of procalin, the major allergen of T. protracta saliva, and contributed more than 50% of the transcripts coding for putative secreted proteins, suggesting that it may play an important role in the blood-feeding process. Other salivary transcripts encoding lipocalin family proteins had homology to triabin (a thrombin inhibitor), triafestin (an inhibitor of kallikrein-kinin system), pallidipin (an inhibitor of collagen-induced platelet aggregation) and others with unknown function.
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75
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Tang X, Jonas AM, Nysten B, Demoustier-Champagne S, Blondeau F, Prévot PP, Pampin R, Godfroid E, Iñiguez B, Colinge JP, Raskin JP, Flandre D, Bayot V. Direct protein detection with a nano-interdigitated array gate MOSFET. Biosens Bioelectron 2009; 24:3531-7. [DOI: 10.1016/j.bios.2009.05.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 05/08/2009] [Accepted: 05/08/2009] [Indexed: 11/29/2022]
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76
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Prevot PP, Beschin A, Lins L, Beaufays J, Grosjean A, Bruys L, Adam B, Brossard M, Brasseur R, Zouaoui Boudjeltia K, Vanhamme L, Godfroid E. Exosites mediate the anti-inflammatory effects of a multifunctional serpin from the saliva of the tick Ixodes ricinus. FEBS J 2009; 276:3235-46. [PMID: 19438720 DOI: 10.1111/j.1742-4658.2009.07038.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Serine protease inhibitors (serpins) are a structurally related but functionally diverse family of ubiquitous proteins. We previously described Ixodes ricinus immunosuppressor (Iris) as a serpin from the saliva of the tick I. ricinus displaying high affinity for human leukocyte elastase. Iris also displays pleotropic effects because it interferes with both the immune response and hemostasis of the host. It thus inhibits lymphocyte proliferation and the secretion of interferon-gamma or tumor necrosis factor-alpha by peripheral blood mononuclear cells, and also platelet adhesion, coagulation and fibrinolysis. Its ability to interfere with coagulation and fibrinolysis, but not platelet adhesion, depends on the integrity of its antiproteolytic reactive center loop domain. Here, we dissect the mechanisms underlying the interaction of recombinant Iris with peripheral blood mononuclear cells. We show that Iris binds to monocytes/macrophages and inhibits their ability to secrete tumor necrosis factor-alpha. Recombinant Iris also has a protective role in endotoxemic shock. The anti-inflammatory ability of Iris does not depend on its antiprotease activity. Moreover, we pinpoint the exosites involved in this activity.
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Affiliation(s)
- Pierre-Paul Prevot
- Laboratoire de Biologie Moléculaire des Ectoparasites, Université Libre de Bruxelles, Gosselies, Belgium
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Francischetti IMB, Sa-Nunes A, Mans BJ, Santos IM, Ribeiro JMC. The role of saliva in tick feeding. FRONT BIOSCI-LANDMRK 2009; 14:2051-88. [PMID: 19273185 PMCID: PMC2785505 DOI: 10.2741/3363] [Citation(s) in RCA: 376] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
When attempting to feed on their hosts, ticks face the problem of host hemostasis (the vertebrate mechanisms that prevent blood loss), inflammation (that can produce itching or pain and thus initiate defensive behavior on their hosts) and adaptive immunity (by way of both cellular and humoral responses). Against these barriers, ticks evolved a complex and sophisticated pharmacological armamentarium, consisting of bioactive lipids and proteins, to assist blood feeding. Recent progress in transcriptome research has uncovered that hard ticks have hundreds of different proteins expressed in their salivary glands, the majority of which have no known function, and include many novel protein families (e.g., their primary structure is unique to ticks). This review will address the vertebrate mechanisms of these barriers as a guide to identify the possible targets of these large numbers of known salivary proteins with unknown function. We additionally provide a supplemental Table that catalogues over 3,500 putative salivary proteins from various tick species, which might assist the scientific community in the process of functional identification of these unique proteins. This supplemental file is accessble fromhttp://exon.niaid.nih.gov/transcriptome/tick_review/Sup-Table-1.xls.gz.
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Affiliation(s)
- Ivo M B Francischetti
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda MD, USA
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The serpin saga; development of a new class of virus derived anti-inflammatory protein immunotherapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 666:132-56. [PMID: 20054981 DOI: 10.1007/978-1-4419-1601-3_11] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Serine proteinase inhibitors, also called serpins, are an ancient grouping of proteins found in primitive organisms from bacteria, protozoa and horseshoe crabs and thus likely present at the time of the dinosaurs, up to all mammals living today. The innate or inflammatory immune system is also an ancient metazoan regulatory system, providing the first line of defense against infection or injury. The innate inflammatory defense response evolved long before acquired, antibody dependent immunity. Viruses have developed highly effective stratagems that undermine and block a wide variety of host inflammatory and immune responses. Some of the most potent of these immune modifying strategies utilize serpins that have also been developed over millions of years, including the hijacking by some viruses for defense against host immune attacks. Serpins represent up to 2-10 percent of circulating plasma proteins, regulating actions as wide ranging as thrombosis, inflammation, blood pressure control and even hormone transport. Targeting serpin-regulated immune or inflammatory pathways makes evolutionary sense for viral defense and many of these virus-derived inhibitory proteins have proven to be highly effective, working at very low concentrations--even down to the femptomolar to picomolar range. We are studying these viral anti-inflammatory proteins as a new class of immunomodulatory therapeutic agents derived from their native viral source. One such viral serpin, Serp-1 is now in clinical trial (conducted by VIRON Therapeutics, Inc.) for acute unstable coronary syndromes (unstable angina and small heart attacks), representing a 'first in class' therapeutic study. Several other viral serpins are also currently under investigation as anti-inflammatory or anti-immune therapeutics. This chapter describes these original studies and the ongoing analysis of viral serpins as a new class of virus-derived immunotherapeutic.
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79
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Expressed sequence tags (ESTs) from the salivary glands of the tick Amblyomma cajennense (Acari: Ixodidae). Toxicon 2008; 51:823-34. [DOI: 10.1016/j.toxicon.2007.12.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 12/11/2007] [Accepted: 12/14/2007] [Indexed: 11/20/2022]
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80
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Abstract
Joppe Hovius and colleagues review anticoagulant and immunosuppressive proteins present in tick saliva, and discuss how immunologically targeting such molecules could prevent transmission of tick-borne pathogens.
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Affiliation(s)
- Joppe W R Hovius
- Center for Experimental and Molecular Medicine, Department of Internal Medicine, University of Amsterdam, Academic Medical Center, Amsterdam, The Netherlands.
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81
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Assumpção TCF, Francischetti IMB, Andersen JF, Schwarz A, Santana JM, Ribeiro JMC. An insight into the sialome of the blood-sucking bug Triatoma infestans, a vector of Chagas' disease. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2008; 38:213-32. [PMID: 18207082 PMCID: PMC2262853 DOI: 10.1016/j.ibmb.2007.11.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 11/06/2007] [Accepted: 11/06/2007] [Indexed: 05/09/2023]
Abstract
Triatoma infestans is a hemiptera, vector of Chagas' disease that feeds exclusively on vertebrate blood in all life stages. Hematophagous insects' salivary glands (SG) produce potent pharmacological compounds that counteract host hemostasis, including anticlotting, antiplatelet, and vasodilatory molecules. To obtain a further insight into the salivary biochemical and pharmacological complexity of this insect, a cDNA library from its SG was randomly sequenced. Also, salivary proteins were submitted to two-dimensional gel (2D-gel) electrophoresis followed by MS analysis. We present the analysis of a set of 1534 (SG) cDNA sequences, 645 of which coded for proteins of a putative secretory nature. Most salivary proteins described as lipocalins matched peptide sequences obtained from proteomic results.
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Affiliation(s)
- Teresa C F Assumpção
- Laboratory of Host-Parasite Interface, University of Brasília, Brasília-DF 70.910-900, Brazil.
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82
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Couvreur B, Beaufays J, Charon C, Lahaye K, Gensale F, Denis V, Charloteaux B, Decrem Y, Prévôt PP, Brossard M, Vanhamme L, Godfroid E. Variability and action mechanism of a family of anticomplement proteins in Ixodes ricinus. PLoS One 2008; 3:e1400. [PMID: 18167559 PMCID: PMC2151134 DOI: 10.1371/journal.pone.0001400] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 12/11/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Ticks are blood feeding arachnids that characteristically take a long blood meal. They must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. This is achieved by expressing batteries of salivary proteins coded by multigene families. METHODOLOGY/PRINCIPAL FINDINGS We report the in-depth analysis of a tick multigene family and describe five new anticomplement proteins in Ixodes ricinus. Compared to previously described Ixodes anticomplement proteins, these segregated into a new phylogenetic group or subfamily. These proteins have a novel action mechanism as they specifically bind to properdin, leading to the inhibition of C3 convertase and the alternative complement pathway. An excess of non-synonymous over synonymous changes indicated that coding sequences had undergone diversifying selection. Diversification was not associated with structural, biochemical or functional diversity, adaptation to host species or stage specificity but rather to differences in antigenicity. CONCLUSIONS/SIGNIFICANCE Anticomplement proteins from I. ricinus are the first inhibitors that specifically target a positive regulator of complement, properdin. They may provide new tools for the investigation of role of properdin in physiological and pathophysiological mechanisms. They may also be useful in disorders affecting the alternative complement pathway. Looking for and detecting the different selection pressures involved will help in understanding the evolution of multigene families and hematophagy in arthropods.
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Affiliation(s)
- Bernard Couvreur
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Jérôme Beaufays
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Cédric Charon
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Kathia Lahaye
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - François Gensale
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Valérie Denis
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Benoît Charloteaux
- Centre de Biophysique Moléculaire Numérique, Gembloux Agricultural University, Gembloux, Belgium
| | - Yves Decrem
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Pierre-Paul Prévôt
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Michel Brossard
- Institute of Zoology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Luc Vanhamme
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
- Laboratory of Molecular Parasitology, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
| | - Edmond Godfroid
- Laboratory for Molecular Biology of Ectoparasites, Institut de Biologie et de Médecine Moléculaires (IBMM), Université Libre de Bruxelles, Gosselies, Belgium
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83
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Merckelbach A, Ruppel A. Biochemical properties of an intracellular serpin from Echinococcus multilocularis. Mol Biochem Parasitol 2007; 156:84-8. [PMID: 17727977 DOI: 10.1016/j.molbiopara.2007.07.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 07/17/2007] [Accepted: 07/18/2007] [Indexed: 11/26/2022]
Abstract
A serpin of the intracellular type from the tapeworm Echinococcus multilocularis was expressed in Escherichia coli, purified by ion exchange chromatography and tested for inhibitory activity against several proteinases. The recombinant protein, which after transcriptional induction, represents about 20 % of total cellular protein, is biochemically active and inhibits trypsin and the trypsin-like plasmin as well as pig pancreatic and human neutrophil elastase. Implications regarding its biochemistry and biological function are discussed.
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Affiliation(s)
- Armin Merckelbach
- Department of Tropical Hygiene and Public Health, University Clinic Heidelberg, Im Neuenheimer Feld 324, 69 120, Heidelberg, Germany.
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84
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Gong H, Zhou J, Liao M, Hatta T, Harnnoi T, Umemiya R, Inoue N, Xuan X, Fujisaki K. Characterization of a carboxypeptidase inhibitor from the tick Haemaphysalis longicornis. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:1079-87. [PMID: 17651749 DOI: 10.1016/j.jinsphys.2007.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Revised: 06/01/2007] [Accepted: 06/05/2007] [Indexed: 05/16/2023]
Abstract
A carboxypeptidase inhibitor called HlTCI was isolated from Haemaphysalis longicornis in this study. The full-length cDNA of HlTCI contains an open reading frame (ORF) of 291bp, encoding 96 amino acid residues consisting of a predicted 19-residue signal peptide and a putative mature 77-residue protein. The expected mature protein is cysteine-rich and has 12 cysteine residues assumed to construct six disulfide bridges. The deduced peptide sequence shows 63.9% homology to the carboxypeptidase inhibitor from another ixodid tick, Rhipicephalus bursa. Reverse-transcription PCR (RT-PCR) indicated that HlTCI was specifically expressed in the ovary from partially engorged adult ticks. The recombinant protein of HlTCI (rHlTCI) with glutathione S-transferase (GST) was expressed in Escherichia coli strain BL21 (DE3) and purified by glutathione-Sepharose 4B beads. rHlTCI showed inhibitory activity against digestive metallocarboxypeptidases A and B, but the activity was affected by the increase of the temperature treatment. High concentrations of rHlTCI were shown to significantly accelerate fibrinolysis in vitro. This effect of rHlTCI on clot lysis suggests its promising potential for use in some thrombotic disorders.
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Affiliation(s)
- Haiyan Gong
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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85
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Mulenga A, Khumthong R, Blandon MA. Molecular and expression analysis of a family of the Amblyomma americanum tick Lospins. J Exp Biol 2007; 210:3188-98. [PMID: 17766296 DOI: 10.1242/jeb.006494] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Serine proteinase inhibitors (serpins) are a family of structurally similar but functionally diverse proteins that regulate several important proteolytic cascades in most branches of life. We have characterized 17 Amblyomma americanum serpin cDNAs here named as `Lospins' (L; an acronym for Lone Star tick serpin) that possess three β-sheets, eight α-helices and a reactive center loop consistent with the consensus serpin superfamily secondary structures. Visual inspection of deduced amino acid sequences revealed two patterns of basic residues: (i) 86DKSRVLKAYKRL97 in L5 and L13–16 and (ii) 158VRDKTRGKI166 in all Lospins, which are similar to consensus glycosaminoglycan (GAG) binding sites (XBnXmBX, where X and B are non-basic and basic residues, n=1 or 2 and m=1, 2 or 3). On three-dimensional models, the two putative GAG binding sites mapped onto α-helices D and F, respectively, with calculation of electrostatic surface potentials revealing basic patches on L5 and L13–16 models that are comparable to the heparin-binding site on antithrombin. RT-PCR expression analysis of 15 selected genes showed that the majority (11/15) of the Lospins were ubiquitously expressed in the midgut, ovary and salivary glands. On a neighbor-joining phylogeny guide tree, 15 serpins from other ticks and 17 Lospins from this study, a total of 32 tick serpin sequences, segregated into five groups with Lospins in groups A and D being conserved across tick species. The discovery of Lospins in this study sets the framework for future studies to understand the role of serpins in tick physiology.
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Affiliation(s)
- Albert Mulenga
- Department of Entomology, College of Agriculture and Life Sciences, Texas A & M University, TAMU 2475, College Station, TX 77843, USA.
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86
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Maritz-Olivier C, Stutzer C, Jongejan F, Neitz AWH, Gaspar ARM. Tick anti-hemostatics: targets for future vaccines and therapeutics. Trends Parasitol 2007; 23:397-407. [PMID: 17656153 DOI: 10.1016/j.pt.2007.07.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Revised: 05/22/2007] [Accepted: 07/09/2007] [Indexed: 11/28/2022]
Abstract
For ticks, a significant obstacle in obtaining a blood meal is counteracting the hemostatic system of the host. To this end, ticks have developed a broad array of anti-hemostatics, which is reflected in the presence of structurally related tick proteins with different functions. Disruption of blood flow which blocks successful tick feeding makes anti-hemostatics attractive targets for anti-tick vaccines. Moreover, the limited number of drugs currently available for a range of important cardio-vascular diseases makes ticks a potential source of novel therapeutics. This review aims to summarize the key features of tick anti-hemostatics, their structures, mode of action and possible future application as vaccines and novel therapeutic agents.
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87
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Prevot PP, Couvreur B, Denis V, Brossard M, Vanhamme L, Godfroid E. Protective immunity against Ixodes ricinus induced by a salivary serpin. Vaccine 2007; 25:3284-92. [PMID: 17270322 DOI: 10.1016/j.vaccine.2007.01.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/18/2006] [Accepted: 01/04/2007] [Indexed: 10/23/2022]
Abstract
Iris is a specific elastase inhibitor expressed in the salivary glands of the hard tick Ixodes ricinus. It belongs to the superfamily of serpins and interferes with both haemostasis and the immune response of the host. In this study, we first show that Iris is expressed in nymphs but not in the female midgut nor in males. We also show that Iris is present in the saliva. To examine its potency as anti-tick vaccine candidate, we set up three models of I. ricinus infestation on immunized animals: nymphs on mice, and adults and nymphs on rabbits. We report the rise of neutralizing antibodies following immunization of rabbits and mice. This comes with a significant protective immunity against ticks in rabbits only, resulting in a 30% mortality rate and a diminution of weight gain in both nymphs and adults and a prolongation of blood feeding time in adults. This is the first report on an anti-tick vaccine trial on I. ricinus using a protein able to interact with both host immunity and haemostasis, as a vaccinating antigen.
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Affiliation(s)
- P-P Prevot
- Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, Rue des Professeurs Jeener et Brachet, 12, B-6041 Gosselies, Belgium
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Ricci CG, Pinto AFM, Berger M, Termignoni C. A thrombin inhibitor from the gut of Boophilus microplus ticks. EXPERIMENTAL & APPLIED ACAROLOGY 2007; 42:291-300. [PMID: 17710557 DOI: 10.1007/s10493-007-9097-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 08/07/2007] [Indexed: 05/16/2023]
Abstract
A thrombin inhibitor was identified for the first time in the gut of the cattle tick Boophilus microplus. Here we present the partial purification and characterization of this new molecule, which was purified from the gut extract by three chromatographic steps: ion-exchange, gel filtration and affinity chromatography in a thrombin-Sepharose resin. In SDS-PAGE the inhibitor showed an apparent molecular mass of circa 26 kDa, which is different from the two thrombin inhibitors present in the saliva of this tick. The new inhibitor delays bovine plasma clotting time and inhibits both thrombin induced fibrinogen clotting and thrombin induced platelet aggregation. However, it does not interfere with thrombin amidolytic activity upon a small substrate (H-D-Phe-Pip-Arg-para-nitroanilide), which does not require binding to thrombin exosites. Therefore, the inhibitor does not block thrombin active site, although it must interfere with one of the thrombin exosites. B. microplus gut thrombin inhibitor (BmGTI) is also capable of enhancing activated protein C (APC) activity upon its specific substrate (H-D-Glu-Pro-Arg-para-nitroanilide), an activity never described before among B. microplus molecules.
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Affiliation(s)
- Clarisse Gravina Ricci
- Centro de Biotecnologia da Universidade Federal do Rio Grande do Sul, 15005, Porto Alegre, 91501-970, Brazil
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