IrFC – An Ixodes ricinus injury-responsive molecule related to Limulus Factor C

Urbanová, Veronika; Hartmann, David J.; Grunclová, Lenka; Šíma, Radek; Flemming, Tina; Hajdušek, Ondřej; Kopáček, Petr

doi:10.1016/j.dci.2014.05.016

Cited by 25 publications

(19 citation statements)

References 38 publications

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“…Proteases are associated with the innate immune system and regulate the activation of complement [ 46 ], clotting [ 47 ], and the prophenoloxidase enzyme [ 48 ]. Ticks appear to possess components of a primordial complement system [ 25 , 49 ]; however, the haemolymph clotting cascade and the existence of a prophenoloxidase system have not been unequivocally demonstrated in ticks [ 2 , 50 ]. IrSigP-44667 is a serine protease that was 842-times overexpressed in the haemocyte library, albeit with a relatively low RPKM of 17.…”

Section: Resultsmentioning

confidence: 99%

Deep Sequencing Analysis of the Ixodes ricinus Haemocytome

et al. 2015

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Background Ixodes ricinus is the main tick vector of the microbes that cause Lyme disease and tick-borne encephalitis in Europe. Pathogens transmitted by ticks have to overcome innate immunity barriers present in tick tissues, including midgut, salivary glands epithelia and the hemocoel. Molecularly, invertebrate immunity is initiated when pathogen recognition molecules trigger serum or cellular signalling cascades leading to the production of antimicrobials, pathogen opsonization and phagocytosis. We presently aimed at identifying hemocyte transcripts from semi-engorged female I. ricinus ticks by mass sequencing a hemocyte cDNA library and annotating immune-related transcripts based on their hemocyte abundance as well as their ubiquitous distribution.Methodology/principal findings De novo assembly of 926,596 pyrosequence reads plus 49,328,982 Illumina reads (148 nt length) from a hemocyte library, together with over 189 million Illumina reads from salivary gland and midgut libraries, generated 15,716 extracted coding sequences (CDS); these are displayed in an annotated hyperlinked spreadsheet format. Read mapping allowed the identification and annotation of tissue-enriched transcripts. A total of 327 transcripts were found significantly over expressed in the hemocyte libraries, including those coding for scavenger receptors, antimicrobial peptides, pathogen recognition proteins, proteases and protease inhibitors. Vitellogenin and lipid metabolism transcription enrichment suggests fat body components. We additionally annotated ubiquitously distributed transcripts associated with immune function, including immune-associated signal transduction proteins and transcription factors, including the STAT transcription factor.Conclusions/significanceThis is the first systems biology approach to describe the genes expressed in the haemocytes of this neglected disease vector. A total of 2,860 coding sequences were deposited to GenBank, increasing to 27,547 the number so far deposited by our previous transcriptome studies that serves as a discovery platform for studies with I. ricinus biochemistry and physiology.

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Section: Resultsmentioning

confidence: 99%

Deep Sequencing Analysis of the Ixodes ricinus Haemocytome

et al. 2015

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“…HaadFC-like and ScsuFC-like lacked the CLECT (C-type lectin domain), and LCCL (Limulus factor C, Coch5b2 and Lgl1) plus CLECT domains, respectively. Moreover, FC-like was identified from two tick species (Ixodes scapularis and Ixodes richius) which possess C3 gene (Urbanová et al, 2014). These results indicate the possibility that the FC-like proteins of these animals are also involved in activation of the complement system.…”

Section: Discussionmentioning

confidence: 85%

Evolution of the complement system in protostomes revealed by de novo transcriptome analysis of six species of Arthropoda

Sekiguchi

Nonaka

2015

Developmental & Comparative Immunology

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“…Because Ixodes sp. ticks possess a primordial complement system involving three molecules related to the C3 complement component and putative convertases (Buresova et al, 2011; Kopacek et al, 2012; Urbanova et al, 2014) we tested for possible effects of tick hemolymph on Borrelia viability. Cultivated B. afzelii spirochete s were incubated with tick cell-free plasma, bovine serum, heat-inactivated bovine serum or BSK-H medium and tested for Borrelia survival after 24 h of incubation in vitro .…”

Section: Resultsmentioning

confidence: 99%

Tick Thioester-Containing Proteins and Phagocytosis Do Not Affect Transmission of Borrelia afzelii from the Competent Vector Ixodes ricinus

Urbanová

Hajdušek

Hönig-Mondeková

et al. 2017

Front. Cell. Infect. Microbiol.

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The present concept of the transmission of Lyme disease from Borrelia-infected Ixodes sp. ticks to the naïve host assumes that a low number of spirochetes that manage to penetrate the midgut epithelium migrate through the hemocoel to the salivary glands and subsequently infect the host with the aid of immunomodulatory compounds present in tick saliva. Therefore, humoral and/or cellular immune reactions within the tick hemocoel may play an important role in tick competence to act as a vector for borreliosis. To test this hypothesis we have examined complement-like reactions in the hemolymph of the hard tick Ixodes ricinus against Borrelia afzelii (the most common vector and causative agent of Lyme disease in Europe). We demonstrate that I. ricinus hemolymph does not exhibit borreliacidal effects comparable to complement-mediated lysis of bovine sera. However, after injection of B. afzelii into the tick hemocoel, the spirochetes were efficiently phagocytosed by tick hemocytes and this cellular defense was completely eliminated by pre-injection of latex beads. As tick thioester-containing proteins (T-TEPs) are components of the tick complement system, we performed RNAi-mediated silencing of all nine genes encoding individual T-TEPs followed by in vitro phagocytosis assays. Silencing of two molecules related to the C3 complement component (IrC3-2 and IrC3-3) significantly suppressed phagocytosis of B. afzelii, while knockdown of IrTep (insect type TEP) led to its stimulation. However, RNAi-mediated silencing of T-TEPs or elimination of phagocytosis by injection of latex beads in B. afzelii-infected I. ricinus nymphs had no obvious impact on the transmission of spirochetes to naïve mice, as determined by B. afzelii infection of murine tissues following tick infestation. This result supports the concept that Borrelia spirochetes are capable of avoiding complement-related reactions within the hemocoel of ticks competent to transmit Lyme disease.

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IrFC – An Ixodes ricinus injury-responsive molecule related to Limulus Factor C

Cited by 25 publications

References 38 publications

Deep Sequencing Analysis of the Ixodes ricinus Haemocytome

Deep Sequencing Analysis of the Ixodes ricinus Haemocytome

Evolution of the complement system in protostomes revealed by de novo transcriptome analysis of six species of Arthropoda

Tick Thioester-Containing Proteins and Phagocytosis Do Not Affect Transmission of Borrelia afzelii from the Competent Vector Ixodes ricinus

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