Evidence of Immune Modulators in the Secretome of the Equine Tapeworm Anoplocephala perfoliata

Abstract

Anoplocephala perfoliata is a neglected gastro-intestinal tapeworm, commonly infecting horses worldwide. Molecular investigation of A. perfoliata is hampered by a lack of tools to better understand the host–parasite interface. This interface is likely influenced by parasite derived immune modulators released in the secretome as free proteins or components of extracellular vesicles (EVs). Therefore, adult RNA was sequenced and de novo assembled to generate the first A. perfoliata transcriptome. In addition, excretory secretory products (ESP) from adult A. perfoliata were collected and EVs isolated using size exclusion chromatography, prior to proteomic analysis of the EVs, the EV surface and EV depleted ESP. Transcriptome analysis revealed 454 sequences homologous to known helminth immune modulators including two novel Sigma class GSTs, five α-HSP90s, and three α-enolases with isoforms of all three observed within the proteomic analysis of the secretome. Furthermore, secretome proteomics identified common helminth proteins across each sample with known EV markers, such as annexins and tetraspanins, observed in EV fractions. Importantly, 49 of the 454 putative immune modulators were identified across the secretome proteomics contained within and on the surface of EVs in addition to those identified in free ESP. This work provides the molecular tools for A. perfoliata to reveal key players in the host–parasite interaction within the horse host.

Parasitic helminths and the host microbiome – a missing ‘extracellular vesicle-sized’ link?

“…Similarly, H. polygyrus ESPs were shown to exert antimicrobial activity against several Gram-negative and Gram-positive bacteria, including E. coli, Salmonella enterica serovar Typhimurium, Enterococcus faecium, and S. aureus [33]. In a recent proteomics analysis of A. suum ESPs, putative AMPs were localised to the EV-rich fraction [31] Trends Trends in in Parasitology Parasitology [31]; Hp, Heligmosomoides polygyrus [48]; Nb, Nippostrongylus brasiliensis [71]; Tc, Teladorsagia circumcincta [23,72]; Tm, Trichuris muris [72]; Fh, Fasciola hepatica [34,37,64]; Ap, Anoplocephala perfoliata [35]; Ta, Taenia asiatica [73]; Hd, Hymenolepis diminuta [74].…”

“…Secretion of exosome-like particles has been ascertained in species of nematodes [23], trematodes [34], and cestodes [35], and confirmed using transmission electron microscopy (TEM) and/or nanoparticle tracking analysis (NTA). Exosome formation involves fusion of late endosomes with the plasma membrane and, as such, exosome-like particles are enriched with proteins of the endosomal sorting complexes required for transport (ESCRT) pathway, for instance, Rabs [36], Vps4 [36], Tyro3, Axl, and Mer (TAM)-binding protein, and TSG101 [37].…”

“…(D) Proteins with putative bacterial agglutination activity based on protein family classification. Abbreviations: As, Ascaris suum[31]; Hp, Heligmosomoides polygyrus[48]; Nb, Nippostrongylus brasiliensis[71]; Tc, Teladorsagia circumcincta[23,72]; Tm, Trichuris muris[72]; Fh, Fasciola hepatica[34,37,64]; Ap, Anoplocephala perfoliata[35]; Ta, Taenia asiatica[73]; Hd, Hymenolepis diminuta[74].…”

Label-free quantitative proteomics and immunoblotting identifies immunoreactive and other excretory-secretory (E/S) proteins of Anoplocephala perfoliata

“…Earlier immunoblotting studies have demonstrated that the antibody response to A. perfoliata E/S proteins of 12 and 13 kDa in size correlate with parasite infection intensity, but the identity of these proteins have remained unknown ( 12 , 13 , 15 ). A recent in-depth RNA sequencing study on this tapeworm generated the first transcriptome for A. perfoliata at its adult stage to support the identification of over 800 E/S proteins produced by this species ( 16 ).…”

Proteomics of Host-Helminth Interactions

“…As such, the study provides an initial basis for understanding the immunological and pathological effects of this infection in humans. Next, Wititkornkul et al examine the immunomodulatory potential of extracellular vesicles (EVs) released by the equine tapeworm Anoplocephala perfoliata [ 12 ]. EVs have emerged as novel vehicles for transfer of helminth-derived molecules to host cells, and, by describing the cargo of A. perfoliata EVs, this paper uncovers potential mechanisms of parasite-to-host communication during infection.…”