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IrSPI, a tick serine protease inhibitor involved in tick feeding and Bartonella henselae infection.

Liu XY, de la Fuente J, Cote M, Galindo RC, Moutailler S, Vayssier-Taussat M, Bonnet SI - PLoS Negl Trop Dis (2014)

Bottom Line: IrSPI silencing impaired tick feeding, as well as resulted in reduced bacterial load in tick SGs.This study provides a comprehensive analysis of I. ricinus SG transcriptome and contributes significant genomic information about this important disease vector.This in-depth knowledge will enable a better understanding of the molecular interactions between ticks and tick-borne pathogens, and identifies IrSPI, a candidate to study now in detail to estimate its potentialities as vaccine against the ticks and the pathogens they transmit.

View Article: PubMed Central - PubMed

Affiliation: USC INRA Bartonella-Tiques, French National Institute of Agricultural Research (UMR BIPAR ENVA-ANSES-UPEC), Maisons-Alfort, France.

ABSTRACT
Ixodes ricinus is the most widespread and abundant tick in Europe, frequently bites humans, and is the vector of several pathogens including those responsible for Lyme disease, Tick-Borne Encephalitis, anaplasmosis, babesiosis and bartonellosis. These tick-borne pathogens are transmitted to vertebrate hosts via tick saliva during blood feeding, and tick salivary gland (SG) factors are likely implicated in transmission. In order to identify such tick factors, we characterized the transcriptome of female I. ricinus SGs using next generation sequencing techniques, and compared transcriptomes between Bartonella henselae-infected and non-infected ticks. High-throughput sequencing of I. ricinus SG transcriptomes led to the generation of 24,539 isotigs. Among them, 829 and 517 transcripts were either significantly up- or down-regulated respectively, in response to bacterial infection. Searches based on sequence identity showed that among the differentially expressed transcripts, 161 transcripts corresponded to nine groups of previously annotated tick SG gene families, while the others corresponded to genes of unknown function. Expression patterns of five selected genes belonging to the BPTI/Kunitz family of serine protease inhibitors, the tick salivary peptide group 1 protein, the salp15 super-family, and the arthropod defensin family, were validated by qRT-PCR. IrSPI, a member of the BPTI/Kunitz family of serine protease inhibitors, showed the highest up-regulation in SGs in response to Bartonella infection. IrSPI silencing impaired tick feeding, as well as resulted in reduced bacterial load in tick SGs. This study provides a comprehensive analysis of I. ricinus SG transcriptome and contributes significant genomic information about this important disease vector. This in-depth knowledge will enable a better understanding of the molecular interactions between ticks and tick-borne pathogens, and identifies IrSPI, a candidate to study now in detail to estimate its potentialities as vaccine against the ticks and the pathogens they transmit.

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Comparison of the expression profile of five I. ricinus genes by next generation sequencing data (NGSD) and qRT-PCR analysis in B. henselae-infected and non-infected ticks.The figure shows differential expression of five genes. KF531922 (IrSPI) and KF531924 respectively associated with BPTI/Kuntiz family of serine protease inhibitors (IrSPI) and Salp15 superfamily protein, which were up-regulated in B. henselae-infected I. ricinus female SGs. KF531923, KF531925, and KF531926 respectively associated with tick salivary peptide group1 protein (20 kDa), Salp15 super-family protein, and arthropod defensins, which were down-regulated in B. henselae-infected I. ricinus female SGs. The fold changes (FC) were converted into log2 values. For qRT-PCR, each sample was run in triplicate and error bars show the SEM (standard error of the mean). The statistical tests yielded significant values at *** P≤0.0001.
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pntd-0002993-g004: Comparison of the expression profile of five I. ricinus genes by next generation sequencing data (NGSD) and qRT-PCR analysis in B. henselae-infected and non-infected ticks.The figure shows differential expression of five genes. KF531922 (IrSPI) and KF531924 respectively associated with BPTI/Kuntiz family of serine protease inhibitors (IrSPI) and Salp15 superfamily protein, which were up-regulated in B. henselae-infected I. ricinus female SGs. KF531923, KF531925, and KF531926 respectively associated with tick salivary peptide group1 protein (20 kDa), Salp15 super-family protein, and arthropod defensins, which were down-regulated in B. henselae-infected I. ricinus female SGs. The fold changes (FC) were converted into log2 values. For qRT-PCR, each sample was run in triplicate and error bars show the SEM (standard error of the mean). The statistical tests yielded significant values at *** P≤0.0001.

Mentions: The expression of five selected transcripts was validated by qRT-PCR on SG RNA samples from a biological replicate (Figure 4). Two transcripts corresponding to the BPTI/Kuntiz family of serine protease inhibitors (GenBank accession number: KF531922) and Salp15 superfamily protein (GenBank accession number: KF531924), respectively were overexpressed by B. henselae infection; three transcripts, corresponding to tick salivary peptide group1 protein (GenBank accession number: KF531923), Salp15 superfamily protein (GenBank accession number: KF531925), and arthropod defensins (GenBank accession number: KF531926), respectively, were down-regulated by B. henselae infection. The fold change (FC) calculation and statistical analysis (p≤0.0001) indicate a clear correlation between the transcript expression profile revealed by next generation sequencing-based data and transcript abundance analyzed by qRT-PCR (Figure 4).


IrSPI, a tick serine protease inhibitor involved in tick feeding and Bartonella henselae infection.

Liu XY, de la Fuente J, Cote M, Galindo RC, Moutailler S, Vayssier-Taussat M, Bonnet SI - PLoS Negl Trop Dis (2014)

Comparison of the expression profile of five I. ricinus genes by next generation sequencing data (NGSD) and qRT-PCR analysis in B. henselae-infected and non-infected ticks.The figure shows differential expression of five genes. KF531922 (IrSPI) and KF531924 respectively associated with BPTI/Kuntiz family of serine protease inhibitors (IrSPI) and Salp15 superfamily protein, which were up-regulated in B. henselae-infected I. ricinus female SGs. KF531923, KF531925, and KF531926 respectively associated with tick salivary peptide group1 protein (20 kDa), Salp15 super-family protein, and arthropod defensins, which were down-regulated in B. henselae-infected I. ricinus female SGs. The fold changes (FC) were converted into log2 values. For qRT-PCR, each sample was run in triplicate and error bars show the SEM (standard error of the mean). The statistical tests yielded significant values at *** P≤0.0001.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109860&req=5

pntd-0002993-g004: Comparison of the expression profile of five I. ricinus genes by next generation sequencing data (NGSD) and qRT-PCR analysis in B. henselae-infected and non-infected ticks.The figure shows differential expression of five genes. KF531922 (IrSPI) and KF531924 respectively associated with BPTI/Kuntiz family of serine protease inhibitors (IrSPI) and Salp15 superfamily protein, which were up-regulated in B. henselae-infected I. ricinus female SGs. KF531923, KF531925, and KF531926 respectively associated with tick salivary peptide group1 protein (20 kDa), Salp15 super-family protein, and arthropod defensins, which were down-regulated in B. henselae-infected I. ricinus female SGs. The fold changes (FC) were converted into log2 values. For qRT-PCR, each sample was run in triplicate and error bars show the SEM (standard error of the mean). The statistical tests yielded significant values at *** P≤0.0001.
Mentions: The expression of five selected transcripts was validated by qRT-PCR on SG RNA samples from a biological replicate (Figure 4). Two transcripts corresponding to the BPTI/Kuntiz family of serine protease inhibitors (GenBank accession number: KF531922) and Salp15 superfamily protein (GenBank accession number: KF531924), respectively were overexpressed by B. henselae infection; three transcripts, corresponding to tick salivary peptide group1 protein (GenBank accession number: KF531923), Salp15 superfamily protein (GenBank accession number: KF531925), and arthropod defensins (GenBank accession number: KF531926), respectively, were down-regulated by B. henselae infection. The fold change (FC) calculation and statistical analysis (p≤0.0001) indicate a clear correlation between the transcript expression profile revealed by next generation sequencing-based data and transcript abundance analyzed by qRT-PCR (Figure 4).

Bottom Line: IrSPI silencing impaired tick feeding, as well as resulted in reduced bacterial load in tick SGs.This study provides a comprehensive analysis of I. ricinus SG transcriptome and contributes significant genomic information about this important disease vector.This in-depth knowledge will enable a better understanding of the molecular interactions between ticks and tick-borne pathogens, and identifies IrSPI, a candidate to study now in detail to estimate its potentialities as vaccine against the ticks and the pathogens they transmit.

View Article: PubMed Central - PubMed

Affiliation: USC INRA Bartonella-Tiques, French National Institute of Agricultural Research (UMR BIPAR ENVA-ANSES-UPEC), Maisons-Alfort, France.

ABSTRACT
Ixodes ricinus is the most widespread and abundant tick in Europe, frequently bites humans, and is the vector of several pathogens including those responsible for Lyme disease, Tick-Borne Encephalitis, anaplasmosis, babesiosis and bartonellosis. These tick-borne pathogens are transmitted to vertebrate hosts via tick saliva during blood feeding, and tick salivary gland (SG) factors are likely implicated in transmission. In order to identify such tick factors, we characterized the transcriptome of female I. ricinus SGs using next generation sequencing techniques, and compared transcriptomes between Bartonella henselae-infected and non-infected ticks. High-throughput sequencing of I. ricinus SG transcriptomes led to the generation of 24,539 isotigs. Among them, 829 and 517 transcripts were either significantly up- or down-regulated respectively, in response to bacterial infection. Searches based on sequence identity showed that among the differentially expressed transcripts, 161 transcripts corresponded to nine groups of previously annotated tick SG gene families, while the others corresponded to genes of unknown function. Expression patterns of five selected genes belonging to the BPTI/Kunitz family of serine protease inhibitors, the tick salivary peptide group 1 protein, the salp15 super-family, and the arthropod defensin family, were validated by qRT-PCR. IrSPI, a member of the BPTI/Kunitz family of serine protease inhibitors, showed the highest up-regulation in SGs in response to Bartonella infection. IrSPI silencing impaired tick feeding, as well as resulted in reduced bacterial load in tick SGs. This study provides a comprehensive analysis of I. ricinus SG transcriptome and contributes significant genomic information about this important disease vector. This in-depth knowledge will enable a better understanding of the molecular interactions between ticks and tick-borne pathogens, and identifies IrSPI, a candidate to study now in detail to estimate its potentialities as vaccine against the ticks and the pathogens they transmit.

Show MeSH
Related in: MedlinePlus