Sergentomyia schwetzi: Salivary gland transcriptome, proteome and enzymatic activities in two lineages adapted to different blood sources

Abstract

During the blood feeding, sand fly females inject saliva containing immunomodulatory and anti-haemostatic molecules into their vertebrate hosts. The saliva composition is species-specific, likely due to an adaptation to particular haemostatic pathways of their preferred host. Research on sand fly saliva is limited to the representatives of two beststudied genera, Phlebotomus and Lutzomyia. Although the members of the genus Sergentomyia are highly abundant in many areas in the Old World, their role in human disease transmission remains uncertain. Most Sergentomyia spp. preferentially attack various species of reptiles, but feeding on warm-blooded vertebrates, including humans and domestic animals, has been repeatedly described, especially for Sergentomyia schwetzi, of which salivary gland transcriptome and proteome is analyzed in the current study. Illumina RNA sequencing and de novo assembly of the reads and their annotation revealed 17,293 sequences homologous to other arthropods' proteins. In the sialome, all proteins typical for sand fly saliva were identified-antigen 5-related, lufaxin, yellowrelated, PpSP15-like, D7-related, ParSP25-like, and silk proteins, as well as less frequent salivary proteins included 71kDa-like, ParSP80-like, SP16-like, and ParSP17-like proteins. Salivary enzymes include apyrase, hyaluronidase, endonuclease, amylase, lipase A2, adenosine deaminase, pyrophosphatase, 5'nucleotidase, and ribonuclease. Proteomics analysis of salivary glands identified 631 proteins, 81 of which are likely secreted into the saliva. We also compared two S. schwetzi lineages derived from the same origin. These lineages were adapted for over 40 generations for blood feeding either on mice (S-M) or geckos (S-G), two vertebrate hosts with different haemostatic mechanisms. Altogether, 20 and 40 annotated salivary transcripts were up-regulated in the S-M and S-G lineage, respectively. Proteomic comparison revealed ten salivary proteins more abundant in the lineage S-M, whereas 66 salivary proteins were enriched in the lineage S-G.

RNA-sequencing of the Nyssomyia neivai sialome: a sand fly-vector from a Brazilian endemic area for tegumentary leishmaniasis and pemphigus foliaceus

“…Finally, Viral products and transposable elements included less than 1% of the families (0.3% and 0.8% respectively) and less than 0.1% of total sequences. Recently, RNA-seq of salivary glands of Old World P. kandelakii 24 and Sergentomyia schwetzi have been published 25 and the presence of representative salivary proteins has been confirmed.…”

“…Homologous salivary proteins with molecular weight of 16.2–16.5 kDa have been identified in New World sand flies. Recently, homologues were also found in Old World sand flies by next generation sequencing of salivary glands from P. kandelakii 24 , as a partial protein, and Sergentomyia schwetzi 25 . The most abundant members of the N. neivai C-type lectins family seem to have a close relationship to N. intermedia homologues (Fig.…”

“…Maxadilan-like proteins have never been identified in Old World Phlebotomus species 17 – 20 , 23 , 27 , 43 . Phlebotomus sand flies, except for P. duboscqi , contain large amounts of vasodilatory adenosine and AMP in their saliva 18 – 20 , 23 , 25 . Interestingly, they lack adenosine deaminase (ADA), an enzyme that hydrolyzes adenosine and adenosine monophosphate (AMP) 53 , 54 .…”

“…The profile of salivary components has been defined in ten Old World Phlebotomus species 16 – 24 , and one Sergentomyia (Sergentomyia schwetzi) species 25 ; notwithstanding, the sialotranscriptome of the New World sand flies have been documented only in four species: Bichromomyia olmeca (Vargas and Diaz-Najera 1959) (syn = Nyssomyia olmeca ), Lutzomyia ayacuchensis (Caceres and Galati 1988) , Lu. longipalpis, and N. intermedia 26 – 29 .…”

Phlebotomus perniciosus Recombinant Salivary Proteins Polarize Murine Macrophages Toward the Anti-Inflammatory Phenotype

“…The complexity of sand fly salivary proteins has already been revealed for several sand fly species (Coutinho-Abreu and Valenzuela, 2018;Oliveira et al, 2020;Polanska et al, 2020), including P. perniciosus (Anderson et al, 2006;Martin-Martin et al, 2013). Several salivary proteins from this sand fly species have been expressed and further tested primarily as markers of exposure (Lestinova et al, 2017;Velez et al, 2018;Willen et al, 2018Willen et al, , 2019Risueno et al, 2019;Burnham et al, 2020;Maia et al, 2020).…”