Characterization of exosome-like vesicles derived from Taenia pisiformis cysticercus and their immunoregulatory role on macrophages

Abstract

Background: Taenia pisiformis is one of the most common intestinal parasites in canines, and leads to serious economic losses in the rabbit breeding industry. Exosome-like vesicles from parasites play crucial roles in host-parasite interactions by transferring cargo from parasites to host cells and by modulating host immunological response through inducing production of host-derived cytokines. Nevertheless, the mechanism by which exosome-like vesicles from T. pisiformis cysticercus regulate the macrophage immune response remains unknown. Methods: Using ultracentrifugation, we isolated exosome-like vesicles from excretory/secretory products (ESP) of T. pisiformis cysticercus. The morphology and size of purified vesicles were confirmed by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The components of proteins and miRNAs within these vesicles were identified by proteomic analysis and high-throughput small RNA sequencing. The biological function of targets of exosomal miRNAs was predicted by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Moreover, the expression of Th1- and Th2-type immune response associated cytokines in RAW264.7 macrophages were evaluated by qPCR and ELISA. We found that exosome-like vesicles were typical cup-shaped vesicles with diameters from 30 to 150 nm. A total of 87 proteins were identified by proteomic analysis, including proteins prominently associated with exosome-like vesicles biogenesis and vesicle trafficking. 41 known miRNAs and 18 novel miRNAs were identified in the exosome-like vesicles. Eleven selected miRNAs, including 7 known miRNAs (miR-71-5p, miR-10a-5p, miR-let-7-5p, miR-745-3p, miR-219-5p, miR-124-3p and miR-4989-3p) and 4 novel miRNAs (novel-mir-3, novel-mir-7, novel-mir-8 and novel-mir-11) were validated to exist in metacestiodes and exosome-like vesicles of T. pisiformis cysticercus by qPCR. The functions of most targets of exosomal miRNAs were mainly associated with signal transduction and the immune system. Additionally, T. pisiformis cysticercus-derived vesicles induced the production of IL-4, IL-6, IL-10, IL-13 and Arg-1, but downregulated the expression of IL-12, IFN-γ and iNOS in RAW264.7 macrophages. Conclusions: We demonstrated that proteins and miRNAs enclosed within exosome-like vesicles from T. pisiformis cysticercus have immunomodulatory functions. Furthermore, exosome-like vesicles were shown to induce the macrophage Th2-type immune response in vitro . Our study suggests that exosome-like vesicles play an important role in the interaction between cysticerci and their hosts. Keywords: Cysticercus pisiformis, Exosome-like vesicles, Macrophages, Th2-type immune response.

In vitro system for the growth and asexual multiplication of Taenia crassiceps cysticerci

“…In addition, the secretion of EVs has been described in the 3 main groups of helminths (Sotillo et al ., 2020) including Taenia spp. (Galán-Puchades et al ., 2016; Ancarola et al ., 2017; Liang et al ., 2019; Wang et al ., 2020). Parasite EVs have been shown to exert phenotypical alterations on host recipient cells (Sánchez-López et al ., 2021); however, the effect of host EVs on parasites or between parasites has not been reported yet.…”

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

“…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]. Conversely, microvesicles have been discovered in secretions from GI helminths, including A. suum [31] and F. hepatica [34]; these originate from direct outward budding of the plasma membrane and are associated with proteins involved in microvesicle formation, including Rho1, MAPK3, flippase, and/or calpain [38].…”