engleski

Virulence factors of Anisakis pegreffii as potential drug therapy targets

Human anisakiasis is a disease caused by infective larvae of the genus Anisakis spp. (Anisakidae, Nematoda), eliciting gastric, intestinal, ectopic or gastro-allergic form, or eventually an asymptomatic form within the Anisakis-seropositive population. Analysing differentially expressed genes (DEGs) after Illumina RNAsequencing of A. pegreffii third-stage infective larvae (L3) experimentally infecting rat (accidental host, model for human infection) and fish (paratenic host), we identified transcripts that expressed the highest upregulation common for L3 migrating through both hosts. From the initial 65 transcripts, deemed virulence factors (VFs), we selected those with at least 2FC expression, discarded constitutive cuticle elements and non-annotated transcripts, obtaining a list of several catalysts and transporters, already recognised as excretory/secretory products. These included five targets: cytosolic non-specific dipeptidase (CNDP2), leukotriene A-4 hydrolase (LKHA4), aspartic protease 6 (ASP6), ATP-binding cassette sub-family B member 9 (ABCB9), and UDPglucuronosyltransferase (UGT3). We searched VFs against the Wormbase Parasite protein BLAST database, obtained predicted proteomes of selected Nematoda (Clades III, V, IV, C, I) and Platyhelminthes (Clades Monogenea, Trematoda, Cestoda, Rhabditophora), determined homologs of A. pegreffii VFs, and identified single-copy orthologous groups (OGs) in selected proteomes (OrthoFinder v 2.5.2). Finally, we determined VFs 3D structures and catalytic sites utilizing online modelling techniques and comparing our models to structures co-crystalized with inhibitors or substrate analogues. Phylogenetic analyses inferred the presence of four families (ABCB9s, ASP6s, LKHA4s and CNDP2s) in almost all Nematoda, Platyhelminthes and Metazoa examined, and the lack of UGT3 in Trematoda and Cestoda. All VFs showed high levels of duplication and widespread occurrence in closely related Toxocara canis, Ascaris suum, Parascaris univalens and H. contortus, supporting their vital biological functions in nematodes. VFs tertiary structure predictions and modelling analyses showed to be useful for the search of currently available inhibitor molecules, being also applicable in a screening of broad-spectrum efficacy for all Clade III and V nematodes examined

Anisakis pegreffii ; anisakiasis ; virulence factors ; drug targets

nije evidentirano