tick-host interface
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Vector-borne diseases constitute 17% of all infectious diseases in the world; among the blood-feeding arthropods, ticks transmit the highest number of pathogens. Understanding the interactions between the tick vector, the mammalian host and the pathogens circulating between them is the basis for the successful development of vaccines against ticks or the tick-transmitted pathogens as well as for the development of specific treatments against tick-borne infections. A lot of effort has been put into transcriptomic and proteomic analyses; however, the protein-carbohydrate interactions and the overall glycobiology of ticks and tick-borne pathogens has not been given the importance or priority deserved. Novel (bio)analytical techniques and their availability have immensely increased the possibilities in glycobiology research and thus novel information in the glycobiology of ticks and tick-borne pathogens is being generated at a faster pace each year. This review brings a comprehensive summary of the knowledge on both the glycosylated proteins and the glycan-binding proteins of the ticks as well as the tick-transmitted pathogens, with emphasis on the interactions allowing the infection of both the ticks and the hosts by various bacteria and tick-borne encephalitis virus.
- MeSH
- Anaplasma patogenita MeSH
- Borrelia patogenita MeSH
- glykomika metody MeSH
- glykosylace MeSH
- interakce hostitele a patogenu fyziologie MeSH
- klíště mikrobiologie fyziologie virologie MeSH
- lektiny metabolismus MeSH
- nemoci přenášené klíšťaty patofyziologie MeSH
- polysacharidy metabolismus MeSH
- proteomika MeSH
- sacharidy fyziologie MeSH
- viry klíšťové encefalitidy patogenita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Ticks counteract host inflammatory responses by secreting proteins from their saliva that compete for histamine binding. Among these tick salivary proteins are lipocalins, antiparallel beta-barrel proteins that sequester small molecules. A tick salivary lipocalin has been structurally resolved and experimentally shown to efficiently compete for histamine with its native receptor (e.g., H1 histamine receptor). To date, molecular dynamics simulations focus on protein-protein and protein-ligand interactions, but there are currently no studies for simultaneous ligand exploration between two competing proteins. METHODS: Aided by state-of-the-art, high-throughput computational methods, the current study simulated and analyzed the dynamics of competitive histamine binding at the tick-host interface using the available crystal structures of both the tick salivary lipocalin histamine-binding protein from Rhipicephalus appendiculatus and the human histamine receptor 1. RESULTS: The attraction towards the tick salivary lipocalin seems to depend on the protonated (adding a hydrogen ion) state of histamine since the current study shows that as histamine becomes more protonated it increases its exploration for the tick salivary lipocalin. This implies that during tick feeding, histamine may need to be protonated for the tick salivary lipocalin to efficiently sequester it in order to counteract inflammation. Additionally, the beta-hairpin loops (at both ends of the tick salivary lipocalin barrel) were reported to have a functional role in sequestering histamine and the results in the current study concur and provide evidence for this hypothesis. These beta-hairpin loops of the tick salivary lipocalin possess more acidic residues than a structurally similar but functionally unrelated lipocalin from the butterfly, Pieris brassicae; comparative results indicate these acidic residues may be responsible for the ability of the tick lipocalin to out-compete the native (H1) receptor for histamine. CONCLUSIONS: Three explanatory types of data can be obtained from the current study: (i) the dynamics of multiple binding sites, (ii) competition between two proteins for a ligand, and (iii) the intrinsic molecular components involved in the competition. These data can provide further insight at the atomic level of the host-tick interface that cannot be experimentally determined. Additionally, the methods used in this study can be applied in rationally designing drugs.
- MeSH
- histamin metabolismus MeSH
- interakce hostitele a patogenu * MeSH
- kinetika MeSH
- lidé MeSH
- lipokaliny chemie metabolismus MeSH
- molekulární modely MeSH
- receptory histaminu H1 chemie metabolismus MeSH
- Rhipicephalus fyziologie MeSH
- simulace molekulární dynamiky MeSH
- vazba proteinů MeSH
- výpočetní biologie metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The hard tick Ixodes ricinus is an important disease vector whose salivary secretions mediate blood-feeding success on vertebrate hosts, including humans. Here we describe the expression profiles and downstream analysis of de novo-discovered microRNAs (miRNAs) expressed in I. ricinus salivary glands and saliva. Eleven tick-derived libraries were sequenced to produce 67,375,557 Illumina reads. De novo prediction yielded 67 bona fide miRNAs out of which 35 are currently not present in miRBase. We report for the first time the presence of microRNAs in tick saliva, obtaining furthermore molecular indicators that those might be of exosomal origin. Ten out of these microRNAs are at least 100 times more represented in saliva. For the four most expressed microRNAs from this subset, we analyzed their combinatorial effects upon their host transcriptome using a novel in silico target network approach. We show that only the inclusion of combinatorial effects reveals the functions in important pathways related to inflammation and pain sensing. A control set of highly abundant microRNAs in both saliva and salivary glands indicates no significant pathways and a far lower number of shared target genes. Therefore, the analysis of miRNAs from pure tick saliva strongly supports the hypothesis that tick saliva miRNAs can modulate vertebrate host homeostasis and represents the first direct evidence of tick miRNA-mediated regulation of vertebrate host gene expression at the tick-host interface. As such, the herein described miRNAs may support future drug discovery and development projects that will also experimentally question their predicted molecular targets in the vertebrate host.
- MeSH
- genové regulační sítě * MeSH
- infestace klíšťaty genetika parazitologie MeSH
- interakce hostitele a parazita genetika MeSH
- klíště genetika MeSH
- mikro RNA analýza genetika MeSH
- obratlovci parazitologie MeSH
- počítačová simulace MeSH
- slinné žlázy metabolismus MeSH
- sliny chemie metabolismus MeSH
- transkriptom * MeSH
- vysoce účinné nukleotidové sekvenování metody MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Tick saliva has been extensively studied in the context of tick-host interactions because it is involved in host homeostasis modulation and microbial pathogen transmission to the host. Accumulated knowledge about the tick saliva composition at the molecular level has revealed that serine protease inhibitors play a key role in the tick-host interaction. Serpins are one highly expressed group of protease inhibitors in tick salivary glands, their expression can be induced during tick blood-feeding, and they have many biological functions at the tick-host interface. Indeed, tick serpins have an important role in inhibiting host hemostatic processes and in the modulation of the innate and adaptive immune responses of their vertebrate hosts. Tick serpins have also been studied as potential candidates for therapeutic use and vaccine development. In this review, we critically summarize the current state of knowledge about the biological role of tick serpins in shaping tick-host interactions with emphasis on the mechanisms by which they modulate host immunity. Their potential use in drug and vaccine development is also discussed.
- MeSH
- inhibitory serinových proteinas fyziologie MeSH
- klíšťata * metabolismus MeSH
- serpiny * metabolismus MeSH
- slinné žlázy metabolismus MeSH
- sliny metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Protease inhibitors (PIs) are ubiquitous regulatory proteins present in all kingdoms. They play crucial tasks in controlling biological processes directed by proteases which, if not tightly regulated, can damage the host organism. PIs can be classified according to their targeted proteases or their mechanism of action. The functions of many PIs have now been characterized and are showing clinical relevance for the treatment of human diseases such as arthritis, hepatitis, cancer, AIDS, and cardiovascular diseases, amongst others. Other PIs have potential use in agriculture as insecticides, anti-fungal, and antibacterial agents. PIs from tick salivary glands are special due to their pharmacological properties and their high specificity, selectivity, and affinity to their target proteases at the tick-host interface. In this review, we discuss the structure and function of PIs in general and those PI superfamilies abundant in tick salivary glands to illustrate their possible practical applications. In doing so, we describe tick salivary PIs that are showing promise as drug candidates, highlighting the most promising ones tested in vivo and which are now progressing to preclinical and clinical trials.
- MeSH
- inhibitory proteas izolace a purifikace terapeutické užití MeSH
- interakce hostitele a parazita genetika imunologie MeSH
- klíšťata metabolismus MeSH
- lidé MeSH
- slinné žlázy metabolismus MeSH
- sliny chemie metabolismus MeSH
- transkriptom genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
UNLABELLED: Lyme disease, caused by spirochetes in the Borrelia burgdorferi sensu lato clade within the Borrelia genus, is transmitted by Ixodes ticks and is currently the most prevalent and rapidly expanding tick-borne disease in Europe and North America. We report complete genome sequences of 47 isolates that encompass all established species in this clade while highlighting the diversity of the widespread human pathogenic species B. burgdorferi. A similar set of plasmids has been maintained throughout Borrelia divergence, indicating that they are a key adaptive feature of this genus. Phylogenetic reconstruction of all sequenced Borrelia genomes revealed the original divergence of Eurasian and North American lineages and subsequent dispersals that introduced B. garinii, B. bavariensis, B. lusitaniae, B. valaisiana, and B. afzelii from East Asia to Europe and B. burgdorferi and B. finlandensis from North America to Europe. Molecular phylogenies of the universally present core replicons (chromosome and cp26 and lp54 plasmids) are highly consistent, revealing a strong clonal structure. Nonetheless, numerous inconsistencies between the genome and gene phylogenies indicate species dispersal, genetic exchanges, and rapid sequence evolution at plasmid-borne loci, including key host-interacting lipoprotein genes. While localized recombination occurs uniformly on the main chromosome at a rate comparable to mutation, lipoprotein-encoding loci are recombination hotspots on the plasmids, suggesting adaptive maintenance of recombinant alleles at loci directly interacting with the host. We conclude that within- and between-species recombination facilitates adaptive sequence evolution of host-interacting lipoprotein loci and contributes to human virulence despite a genome-wide clonal structure of its natural populations. IMPORTANCE: Lyme disease (also called Lyme borreliosis in Europe), a condition caused by spirochete bacteria of the genus Borrelia, transmitted by hard-bodied Ixodes ticks, is currently the most prevalent and rapidly expanding tick-borne disease in the United States and Europe. Borrelia interspecies and intraspecies genome comparisons of Lyme disease-related bacteria are essential to reconstruct their evolutionary origins, track epidemiological spread, identify molecular mechanisms of human pathogenicity, and design molecular and ecological approaches to disease prevention, diagnosis, and treatment. These Lyme disease-associated bacteria harbor complex genomes that encode many genes that do not have homologs in other organisms and are distributed across multiple linear and circular plasmids. The functional significance of most of the plasmid-borne genes and the multipartite genome organization itself remains unknown. Here we sequenced, assembled, and analyzed whole genomes of 47 Borrelia isolates from around the world, including multiple isolates of the human pathogenic species. Our analysis elucidates the evolutionary origins, historical migration, and sources of genomic variability of these clinically important pathogens. We have developed web-based software tools (BorreliaBase.org) to facilitate dissemination and continued comparative analysis of Borrelia genomes to identify determinants of human pathogenicity.
- MeSH
- Borrelia burgdorferi komplex genetika klasifikace MeSH
- Borrelia burgdorferi genetika klasifikace MeSH
- Borrelia genetika klasifikace MeSH
- fylogeneze * MeSH
- genetická variace MeSH
- genom bakteriální * MeSH
- interakce mikroorganismu a hostitele genetika MeSH
- klíště mikrobiologie MeSH
- lidé MeSH
- lipoproteiny * genetika MeSH
- lymeská nemoc * mikrobiologie přenos MeSH
- molekulární evoluce MeSH
- plazmidy genetika MeSH
- rekombinace genetická * MeSH
- sekvenování celého genomu MeSH
- selekce (genetika) * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa MeSH
- Severní Amerika MeSH
Recent molecular and cellular studies have highlighted a potentially important role for tick exosomes in parasite transmission. Here we summarize evolving hypotheses about the largely unknown cellular events that may take place at the tick-host-pathogen interface, focusing on a potential role for arthropod exosomes in this tripartite interaction.
Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes is likely mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia), rickettsiae (Anaplasma), and protozoans (Babesia). Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens.
- MeSH
- Anaplasma imunologie patogenita MeSH
- arachnida jako vektory imunologie mikrobiologie parazitologie MeSH
- Babesia imunologie patogenita MeSH
- Borrelia imunologie patogenita MeSH
- interakce hostitele a patogenu * MeSH
- klíšťata imunologie mikrobiologie parazitologie MeSH
- přirozená imunita * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Introduction: We developed a new simple method to assess the composition of proteinaceous components in the saliva of Ornithodoros moubata, the main vehicle for pathogen transmission and a likely source of bioactive molecules acting at the tick-vertebrate host interface. To collect naturally expectorated saliva from the ticks we employed an artificial membrane feeding technique using a simple, chemically defined diet containing phagostimulants and submitted native saliva samples collected in this way for liquid chromatography-mass spectrometry (LC-MS) analysis. These experiments were conducted with groups of uninfected ticks as well as with O. moubata infected with B. duttonii. The ticks exhibited a fair feeding response to the tested diet with engorgement rates reaching as high as 60-100% of ticks per feeding chamber. The LC-MS analysis identified a total of 17 and 15 proteins in saliva samples from the uninfected and infected O. moubata nymphs, respectively. Importantly, the analysis was sensitive enough to detect up to 9 different proteins in the samples of saliva containing diet upon which as few as 6 nymphal ticks fed during the experiments. Some of the proteins recognized in the analysis are well known for their immunomodulatory activity in a vertebrate host, whereas others are primarily thought of as structural or "housekeeping" proteins and their finding in the naturally expectorated tick saliva confirms that they can be secreted and might serve some functions at the tick-host interface. Most notably, some of the proteins that have long been suspected for their importance in the vector-pathogen interactions of Borrelia spirochetes were detected only in the samples from infected ticks, suggesting that their expression was altered by the persistent colonization of the tick's salivary glands by spirochetes. The simple method described herein is an important addition to the toolbox available to study the vector-host-pathogen interactions in the rapidly feeding soft ticks.
- MeSH
- Argasidae * MeSH
- Borrelia * fyziologie MeSH
- Ornithodoros * MeSH
- sliny MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Anaplasma phagocytophilum transmembrane and surface proteins play a role during infection and multiplication in host neutrophils and tick vector cells. Recently,A. phagocytophilumMajor surface protein 4 (MSP4) and Heat shock protein 70 (HSP70) were shown to be localized on the bacterial membrane, with a possible role during pathogen infection in ticks. In this study, we hypothesized thatA. phagocytophilumMSP4 and HSP70 have similar functions in tick-pathogen and host-pathogen interactions. To address this hypothesis, herein we characterized the role of these bacterial proteins in interaction and infection of vertebrate host cells. The results showed thatA. phagocytophilumMSP4 and HSP70 are involved in host-pathogen interactions, with a role for HSP70 during pathogen infection. The analysis of the potential protective capacity of MSP4 and MSP4-HSP70 antigens in immunized sheep showed that MSP4-HSP70 was only partially protective against pathogen infection. This limited protection may be associated with several factors, including the recognition of non-protective epitopes by IgG in immunized lambs. Nevertheless, these antigens may be combined with other candidate protective antigens for the development of vaccines for the control of human and animal granulocytic anaplasmosis. Focusing on the characterization of host protective immune mechanisms and protein-protein interactions at the host-pathogen interface may lead to the discovery and design of new effective protective antigens.
- MeSH
- Anaplasma phagocytophilum genetika metabolismus MeSH
- bakteriální proteiny genetika metabolismus MeSH
- ehrlichióza mikrobiologie veterinární MeSH
- interakce hostitele a patogenu MeSH
- membránové proteiny genetika metabolismus MeSH
- nemoci ovcí mikrobiologie MeSH
- ovce MeSH
- proteiny tepelného šoku HSP70 genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
