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

Abstract

Leishmaniasis encompasses a spectrum of diseases caused by a protozoan belonging to the genus Leishmania. The parasite is transmitted by the bite of sand flies, which inoculate the promastigote forms into the host’s skin while acquiring a blood meal. Nyssomyia neivai is one of the main vectors of tegumentary leishmaniasis (TL) in Brazil. Southeastern Brazil is an endemic region for TL but also overlaps with an endemic focus for pemphigus foliaceus (PF), also known as Fogo Selvagem. Salivary proteins of sand flies, specifically maxadilan and LJM11, have been related to pemphigus etiopathogenesis in the New World, being proposed as an environmental trigger for autoimmunity. We present a comprehensive description of the salivary transcriptome of the N. neivai, using deep sequencing achieved by the Illumina protocol. In addition, we highlight the abundances of several N. neivai salivary proteins and use phylogenetic analysis to compare with Old- and New-World sand fly salivary proteins. The collection of protein sequences associated with the salivary glands of N. neivai can be useful for monitoring vector control strategies as biomarkers of N. neivai, as well as driving vector-vaccine design for leishmaniasis. Additionally, this catalog will serve as reference to screen for possible antigenic peptide candidates triggering anti-Desmoglein-1 autoantibodies.

Genetic Associations and Differential mRNA Expression Levels of Host Genes Suggest a Viral Trigger for Endemic Pemphigus Foliaceus

“…The triggering factor could be a salivary protein or a virus. The possibility that salivary proteins of insects could induce EPF has been considered to some extent [ 11 , 12 , 45 , 46 ], but the hypothesis of a viral trigger has not received much attention. However, viruses have been associated with several autoimmune diseases, and autoimmune manifestations may occur in viral infections [ 47 , 48 ].…”

Advances in Understanding Leishmania Pathobiology: What Does RNA-Seq Tell Us?

“…The salivary transcriptome of the Nyssomyia neivai sandfly, one of the main vectors of tegumentary leishmaniasis in Brazil, has also been recently performed and highlighted the abundances of several N. neivai salivary proteins which can be used as biomarkers of N. neivai ( Vernal et al, 2020 ). Thus, looking into the microbial diversity of sandfly vectors gut is of particular interest.…”