Tick-borne encephalitis virus (TBEV) is flavivirus transmitted to the host via tick saliva which contains various molecules with biological impacts. One of such molecules is Iristatin, a cysteine protease inhibitor from Ixodes ricinus that has been shown to have immunomodulatory properties. To characterize Iristatin in the relation to TBEV, we investigate whether this tick inhibitor has any capacity to influence TBEV infection. Mice were intradermally infected by TBEV with or without Iristatin and the viral multiplication was determined in skin and brain tissues by RT-PCR two and 5 days after infection. The viral RNA was detected in both intervals in skin and increased by time. The application of Iristatin caused a reduction in viral RNA in skin but not in the brain of infected mice 5 days post-infection. Moreover, anti-viral effect of Iristatin on skin was accompanied by a significant decline of interferon-stimulated gene 15 gene expression. The effect of Iristatin on TBEV replication was tested also in vitro in primary macrophages and dendritic cells; however, no changes were observed suggesting no direct interference of Iristatin with virus replication. Still, the Iristatin caused a suppression of Erk1/2 phosphorylation in TBEV-infected dendritic cells and had the anti-apoptotic effect. This is the first report showing that a tick cystatin decreases the viral RNA in the host skin, likely indirectly through creating skin environment that is less supportive for TBEV replication. Assuming, that viral RNA reflects the amount of infectious virus, decline of TBEV in host skin could influence the tick biology or virus transmission during cofeeding.

• Klíčová slova
• Cystatin, Flavivirus, Tick, Tick-borne encephalitis virus, Virus replication,
• MeSH
• antivirové látky * MeSH
• cystatiny * MeSH
• dendritické buňky virologie   MeSH
• klíště * chemie   MeSH
• klíšťová encefalitida * virologie   MeSH
• kůže * virologie   MeSH
• makrofágy virologie   MeSH
• mozek virologie   MeSH
• myši MeSH
• replikace viru * účinky léků   MeSH
• RNA virová analýza   MeSH
• slinné cystatiny * farmakologie   MeSH
• viry klíšťové encefalitidy * účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antivirové látky * MeSH
• cystatiny * MeSH
• RNA virová MeSH
• slinné cystatiny * MeSH

To successfully feed, ticks inject pharmacoactive molecules into the vertebrate host including cystatin cysteine protease inhibitors. However, the molecular and cellular events modulated by tick saliva remain largely unknown. Here, we describe and characterize a novel immunomodulatory cystatin, Iristatin, which is upregulated in the salivary glands of feeding Ixodes ricinus ticks. We present the crystal structure of Iristatin at 1.76 Å resolution. Purified recombinant Iristatin inhibited the proteolytic activity of cathepsins L and C and diminished IL-2, IL-4, IL-9, and IFN-γ production by different T-cell populations, IL-6 and IL-9 production by mast cells, and nitric oxide production by macrophages. Furthermore, Iristatin inhibited OVA antigen-induced CD4+ T-cell proliferation and leukocyte recruitment in vivo and in vitro. Our results indicate that Iristatin affects wide range of anti-tick immune responses in the vertebrate host and may be exploitable as an immunotherapeutic.

• Klíčová slova
• Cathepsin, Crystal structure, Immune responses, Ixodes ricinus, Saliva,
• MeSH
• cystatiny klasifikace   genetika   farmakologie   MeSH
• cytokiny metabolismus   MeSH
• epoxidové sloučeniny metabolismus   MeSH
• fylogeneze MeSH
• imunosupresiva chemie   metabolismus   farmakologie   MeSH
• klíště chemie   genetika   metabolismus   MeSH
• krystalografie rentgenová MeSH
• makrofágy účinky léků   metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• proteiny členovců chemie   genetika   farmakologie   MeSH
• proteolýza účinky léků   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• slinné cystatiny chemie   genetika   farmakologie   MeSH
• T-lymfocyty účinky léků   metabolismus   MeSH
• tyrosin analogy a deriváty   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cathestatin C MeSH Prohlížeč
• cystatiny MeSH
• cytokiny MeSH
• epoxidové sloučeniny MeSH
• imunosupresiva MeSH
• oxid dusnatý MeSH
• proteiny členovců MeSH
• slinné cystatiny MeSH
• tyrosin MeSH

To ensure successful feeding tick saliva contains a number of inhibitory proteins that interfere with the host immune response and help to create a permissive environment for pathogen transmission. Among the potential targets of the salivary cystatins are two host cysteine proteases, cathepsin S, which is essential for antigen- and invariant chain-processing, and cathepsin C (dipeptidyl peptidase 1, DPP1), which plays a critical role in processing and activation of the granule serine proteases. Here, the effect of salivary cystatin OmC2 from Ornithodoros moubata was studied using differentiated MUTZ-3 cells as a model of immature dendritic cells of the host skin. Following internalization, cystatin OmC2 was initially found to inhibit the activity of several cysteine cathepsins, as indicated by the decreased rates of degradation of fluorogenic peptide substrates. To identify targets, affinity chromatography was used to isolate His-tagged cystatin OmC2 together with the bound proteins from MUTZ-3 cells. Cathepsins S and C were identified in these complexes by mass spectrometry and confirmed by immunoblotting. Furthermore, reduced increase in the surface expression of MHC II and CD86, which are associated with the maturation of dendritic cells, was observed. In contrast, human inhibitor cystatin C, which is normally expressed and secreted by dendritic cells, did not affect the expression of CD86. It is proposed that internalization of salivary cystatin OmC2 by the host dendritic cells targets cathepsins S and C, thereby affecting their maturation.

• Klíčová slova
• DPP1, cathepsin C, cathepsin S, cystatin OmC2, dendritic cells, dipeptidyl peptidase 1, lysosomal proteases, tick saliva,
• MeSH
• antigeny CD86 MeSH
• antigeny diferenciační B-lymfocytární MeSH
• buněčné linie MeSH
• cystatiny metabolismus   MeSH
• dendritické buňky imunologie   metabolismus   MeSH
• epoxidové sloučeniny imunologie   metabolismus   MeSH
• geny MHC třídy II imunologie   MeSH
• kathepsin C metabolismus   MeSH
• kathepsiny chemie   imunologie   metabolismus   MeSH
• klíšťata enzymologie   MeSH
• lidé MeSH
• lyzozomy enzymologie   MeSH
• MHC antigeny II. třídy MeSH
• Ornithodoros enzymologie   MeSH
• rekombinantní proteiny MeSH
• sliny enzymologie   MeSH
• tyrosin analogy a deriváty   imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD86 MeSH
• antigeny diferenciační B-lymfocytární MeSH
• cathepsin S MeSH Prohlížeč
• cathestatin C MeSH Prohlížeč
• CTSC protein, human MeSH Prohlížeč
• cystatiny MeSH
• epoxidové sloučeniny MeSH
• invariant chain MeSH Prohlížeč
• kathepsin C MeSH
• kathepsiny MeSH
• MHC antigeny II. třídy MeSH
• rekombinantní proteiny MeSH
• tyrosin MeSH

The publication of the first tick sialome (salivary gland transcriptome) heralded a new era of research of tick protease inhibitors, which represent important constituents of the proteins secreted via tick saliva into the host. Three major groups of protease inhibitors are secreted into saliva: Kunitz inhibitors, serpins, and cystatins. Kunitz inhibitors are anti-hemostatic agents and tens of proteins with one or more Kunitz domains are known to block host coagulation and/or platelet aggregation. Serpins and cystatins are also anti-hemostatic effectors, but intriguingly, from the translational perspective, also act as pluripotent modulators of the host immune system. Here we focus especially on this latter aspect of protease inhibition by ticks and describe the current knowledge and data on secreted salivary serpins and cystatins and their role in tick-host-pathogen interaction triad. We also discuss the potential therapeutic use of tick protease inhibitors.

• Klíčová slova
• cystatins, immunomodulation, protease inhibitors, serpins, tick-host interaction,
• MeSH
• cystatiny fyziologie   terapeutické užití   MeSH
• imunomodulace MeSH
• inhibitory proteas klasifikace   metabolismus   terapeutické užití   MeSH
• inhibitory serinových proteinas fyziologie   terapeutické užití   MeSH
• interakce hostitele a parazita MeSH
• klíšťata metabolismus   MeSH
• lidé MeSH
• serpiny fyziologie   terapeutické užití   MeSH
• sliny enzymologie   metabolismus   MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• cystatiny MeSH
• inhibitory proteas MeSH
• inhibitory serinových proteinas MeSH
• serpiny MeSH

The saliva of ixodid ticks contains a mixture of bioactive molecules that target a wide spectrum of host defense mechanisms to allow ticks to feed on the vertebrate host for several days. Tick salivary proteins cluster in multigenic protein families, and individual family members display redundancy and pluripotency in their action to ameliorate or evade host immune responses. It is now clear that members of different protein families can target the same cellular or molecular pathway of the host physiological response to tick feeding. We present and discuss our hypothesis that redundancy and pluripotency evolved in tick salivary immunomodulators to evade immune recognition by the host while retaining the immunomodulatory potential of their saliva.

• Klíčová slova
• immunomodulation, multigenic protein families, pluripotency, redundancy, silent antigens, tick salivary proteins,
• MeSH
• arachnida jako vektory imunologie   parazitologie   MeSH
• imunitní únik imunologie   MeSH
• interakce hostitele a parazita imunologie   MeSH
• Ixodidae imunologie   parazitologie   MeSH
• lidé MeSH
• parazitární nemoci imunologie   přenos   MeSH
• proteiny členovců imunologie   MeSH
• slinné proteiny a peptidy imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• proteiny členovců MeSH
• slinné proteiny a peptidy MeSH

Tick saliva facilitates tick feeding and infection of the host. Gene expression analysis of tick salivary glands and other tissues involved in host-pathogen interactions has revealed a wide range of bioactive tick proteins. Transcriptomic analysis has been a milestone in the field and has recently been enhanced by next-generation sequencing (NGS). Furthermore, the application of quantitative proteomics to ticks with unknown genomes has provided deeper insights into the molecular mechanisms underlying tick hematophagy, pathogen transmission, and tick-host-pathogen interactions. We review current knowledge on the transcriptomics and proteomics of tick tissues from a systems-biology perspective and discuss future challenges in the field.

• Klíčová slova
• next-generation sequencing, sialomes, systems biology, tick-borne pathogens,
• MeSH
• interakce hostitele a parazita genetika   fyziologie   MeSH
• klíšťata genetika   metabolismus   MeSH
• lidé MeSH
• proteom * MeSH
• systémová biologie * MeSH
• transkriptom * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• proteom * MeSH