Exploring the non-coding RNA in tsetse fly saliva and its effect on the host innate immune response and trypanosome development at the host skin bite site.

Tsetse flies transmit African trypanosomes, a set of parasites causing devastating diseases in humans and animals. Transmission involves injection of trypanosome-infected saliva at the bite site. The parasites then reside in the skin for a few hours before causing systemic infections. The injected tsetse saliva is a complex potion of protein and non-protein components among which non-coding RNA. Non-coding RNA (ncRNA) constitutes a group of RNA lacking the ability to encode proteins that has been shown to play key role in gene expression regulation in many organisms. Although their presence and some functions have been reported in the saliva of some blood-feeding vectors, studies on tsetse fly saliva ncRNAs are still in their infancy stages and thus limited information to understand their roles in parasite-vector-host interaction. The aim of this study will be to identify the non-coding RNA landscape in Trypanosoma brucei infected tsetse saliva and assess their impact on the host immune response that could affect the early trypanosome establishment at the site of bite. We will use small and total RNA sequence data from T. brucei-infected saliva, salivary gland and metacyclic trypanosome samples coupled with computational and bioinformatics analysis to i) identify ncRNA, ii) investigate the impact of trypanosome infection on these transcripts, iii) predict their target host immunity genes, and iv) start pathway and functional analysis. The main outcome of this study will be novel knowledge on ncRNA regulatory elements in tsetse saliva that could play a role in the early host immune response modulation and trypanosome establishment at the host bite site, an essential step in the tsetse-to-mammalian host life cycle transition. This knowledge could open new research avenues to be explored to interfere with the parasite's early development after tsetse fly transmissions at the bite site.