Highlights of the São Paulo ISEV workshop on extracellular vesicles in cross-kingdom communication.

In the past years, extracellular vesicles (EVs) have become an important field of research since EVs have been found to play a central role in biological processes. In pathogens, EVs are involved in several events during the host-pathogen interaction, including invasion, immunomodulation, and pathology as well as parasite-parasite communication. In this report, we summarised the role of EVs in infections caused by viruses, bacteria, fungi, protozoa, and helminths based on the talks and discussions carried out during the International Society for Extracellular Vesicles (ISEV) workshop held in São Paulo (November, 2016), Brazil, entitled Cross-organism Communication by Extracellular Vesicles: Hosts, Microbes and Parasites.

Profiling circulating miRNAs in serum from pigs infected with the porcine whipworm, Trichuris suis.

microRNAs (miRNAs) are recently discovered as key regulators of gene translation and are becoming increasingly recognized for their involvement in various diseases. This study investigates the miRNA profile in pig serum during the course of an infection with the gastrointestinal parasite, Trichuris suis. Of this panel, the expression of selected miRNAs in serum from T. suis infected and uninfected pigs were determined by quantitative real time PCR using Exiqon Human Panel assays at 0, 2, 4, 6, 8 and 10 weeks post first infection (wpi). One miRNA, ssc-let-7d-3p, was significantly up-regulated in infected pigs 8 wpi. Interestingly, ssc-let-7d-3p shows high complementary to tsu-let-7a, which is the most highly transcribed miRNA in T. suis. The let-7 family miRNAs have been shown to post-transcriptionally regulate the translation of the helminth-controlling cytokine, IL-13, in a murine model for asthma and we hypothesize possible interactions between these host- and parasite-derived miRNAs and their immunomodulating roles.

Secretion of RNA-Containing Extracellular Vesicles by the Porcine Whipworm, Trichuris suis.

Trichuris suis is a common parasitic helminth of pigs. As with many other parasites, T. suis ensures its own survival by evading host immune responses, but little is known about how this is achieved. MicroRNAs (miRNA) have been shown to be involved in various immunological processes by post-transcriptional regulation of specific genes, and the potential of using these molecules as biomarkers of disease is currently being examined. It has recently been shown that parasites may secrete extracellular structures such as exosomes and microvesicles, containing proteins and miRNA. The fusion of these structures with host cells has been demonstrated, and a role of exosome-derived miRNA in host gene regulation has been suggested. In the present study, we show that exosome- and microvesicular-like structures are secreted by T. suis L1 larvae and also demonstrate the presence of miRNA-sized RNA inside these structures. A potential role of these molecules in host-parasite interactions is suggested. In addition, an electron-dense layer covering the surface of the larvae was observed, which may play a function in host immune evasion.