Cystatins play role in tick blood feeding and pathogen infection

Background: Intracellular tick-borne pathogens have developed mechanisms to survive in both the arthropod vector and reservoir host, by differentially expressing genes depending on their environment.  We hypothesized that tick cystatins play important role in tick blood feeding, pathogen colonization and transmission in ticks. In this study, three secretory tick cystatins from the <i>Amblyomma maculatum</i> sialotranscriptome were selected for further characterization based on their differential expression upon blood meal regulation.

Methodology/Principal findings: The gene expression profile in tick tissues provided an evidence for physiological role during the slow or fast blood feeding stage. The functional assay with RNA interference of selected cystatins showed the reduction in tick blood meal uptake. Though, the exact mechanism of tick cystatin protein family in<i> R. parkeri </i>pathogenesis is not known yet. Expression of cystatins genes were differentially expressed with <i> R. parkeri </i> infection which may facilitate pathogen for colonization and proliferation.

Conclusions/Significance: Our results underscore the importance of tick cystatins during blood meal acquisition and pathogen infection.