Sialome diversity of ticks revealed by RNAseq of single tick salivary glands

• Published in: PLoS neglected tropical diseases Vol. 12; no. 4; p. e0006410
• Main Authors: Perner, Jan, Kropáčková, Sára, Kopáček, Petr, Ribeiro, José M. C.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 13.04.2018; Public Library of Science (PLoS)
• Subjects: Amblyomma americanum; Angiogenesis; Animals; Arachnids; Biodiversity; Bioinformatics; Biology; Biology and Life Sciences; Blood; Borrelia burgdorferi; Cluster analysis; Components; Composition; Computational Biology; Feeding; Feeding behavior; Female; Females; Gene expression; Gene Expression Profiling; Genes; Genetic aspects; Genomics; Glands; Health aspects; High-Throughput Nucleotide Sequencing - methods; Host-parasite relationships; Humans; Identification and classification; Immunologic research; Immunological factors; Immunomodulation; Ixodes - genetics; Ixodes - metabolism; Ixodes ricinus; Ixodes scapularis; Laboratory animals; Libraries; Lipocalin; Male; Medicine and Health Sciences; Messenger RNA; Multivariate analysis; Parasitology; Peptides; Physiological aspects; Polypeptides; Proteins; Proteomics; Rabbits; Research and Analysis Methods; Saliva; Saliva - metabolism; Salivary gland; Salivary glands; Salivary Glands - metabolism; Sequence Analysis, RNA; Ticks; Transcriptome; Trends; Tropical diseases; Uniqueness; Czech Republic
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0006410

Ticks salivate while feeding on their hosts. Saliva helps blood feeding through host anti-hemostatic and immunomodulatory components. Previous transcriptomic and proteomic studies revealed the complexity of tick saliva, comprising hundreds of polypeptides grouped in several multi-genic families such as lipocalins, Kunitz-domain containing peptides, metalloproteases, basic tail secreted proteins, and several other families uniquely found in ticks. These studies also revealed that the composition of saliva changes with time; expression of transcripts from the same family wax and wane as a function of feeding time. Here, we examined whether host immune factors could influence sialome switching by comparing sialomes of ticks fed naturally on a rabbit, to ticks artificially fed on defibrinated blood depleted of immune components. Previous studies were based on transcriptomes derived from pools of several individuals. To get an insight into the uniqueness of tick sialomes, we performed transcriptomic analyses of single salivary glands dissected from individual adult female I. ricinus ticks. Multivariate analysis identified 1,279 contigs differentially expressed as a function of time and/or feeding mode. Cluster analysis of these contigs revealed nine clusters of differentially expressed genes, four of which appeared consistently across several replicates, but five clusters were idiosyncratic, pointing to the uniqueness of sialomes in individual ticks. The disclosure of tick quantum sialomes reveals the unique salivary composition produced by individual ticks as they switch their sialomes throughout the blood meal, a possible mechanism of immune evasion.