Special considerations for studies of extracellular vesicles from parasitic helminths: A community‐led roadmap to increase rigour and reproducibility

Over the last decade, research interest in defining how extracellular vesicles (EVs) shape cross-species communication has grown rapidly. Parasitic helminths, worm species found in the phyla Nematoda and Platyhelminthes, are well-recognised manipulators of host immune function and physiology. Emerging evidence supports a role for helminth-derived EVs in these processes and highlights EVs as an important participant in cross-phylum communication. While the mammalian EV field is guided by a community-agreed framework for studying EVs derived from model organisms or cell systems [e.g., Minimal Information for Studies of Extracellular Vesicles (MISEV)], the helminth community requires a supplementary set of principles due to the additional challenges that accompany working with such divergent organisms. These challenges include, but are not limited to, generating sufficient quantities of EVs for descriptive or functional studies, defining pan-helminth EV markers, genetically modifying these organisms, and identifying rigorous methodologies for in vitro and in vivo studies. Here, we outline best practices for those investigating the biology of helminth-derived EVs to complement the MISEV guidelines. We summarise community-agreed standards for studying EVs derived from this broad set of non-model organisms, raise awareness of issues associated with helminth EVs and provide future perspectives for how progress in the field will be achieved

Isolation and characterisation of extracellular vesicles of parasitic helminths

Excretory-secretory products (ESP) serve as important mediators of intercellular and inter-species communication. They were originally thought to be secreted mainly in a soluble form, but recent discoveries indicate their delivery through extracellular vesicles (EVs). These membraneous particles provide protection from degradation for some of their components, as well as targeted delivery through various receptors on their surface. As such they have been studied as potent immunomodulators in host-pathogen relationships. With respect to parasitic helminths, EVs are being studied as agents for diagnosis, vaccination or therapeutics. However, their general biology, especially their biogenesis patterns, is still poorly understood compared to their functional role.Therefore, the goal of this thesis is to investigate in more detail the secretion activity of EVs in different tapeworms and their life-cycle stages. Under laboratory conditions, the life cycle of Schistocephalus solidus, a tapeworm with an aquatic life cycle, was established to explore EVs secretion at different developmental stages. Moreover, we used proteomic analyses and ultrastructural observations to identify the main biogenesis pathways behind EVs secretion in a terrestrial tapeworm Hymenolepis diminuta. This also allowed for the comparison of EVs generation in tapeworms with different host types

Molecular and morphological characterisation of digeneans of the family Strigeidae Railliet, 1919 from Iceland

This study applies molecular and morphological procedures to identify larval and adult stages of trematodes of the family Strigeidae in Iceland. Intermediate hosts (snails and fishes) and definitive host (birds) from 11 freshwater lakes were sampled and examined for the presence of trematodes. Recovered species were subjected to study of morphology, sequencing and phylogenetic analyses. A total of seven species of three genera were identified via phylogenetical analyses based on mitochondrial (cox1) and nuclear (28S) sequences, and morphological data. The life-cycle of Apatemon gracilis was fully elucidated in Iceland, and those of Australapatemon burti and Australapatemon minor in part (cercariae and adults). The relationship of Cotylurus sp. 'Lin. 1I' and Cotylurus sp. 'Lin. 2I' could not be resolved

Special considerations for studies of extracellular vesicles from parasitic helminths:A community-led roadmap to increase rigour and reproducibility

Over the last decade, research interest in defining how extracellular vesicles (EVs) shape cross‐species communication has grown rapidly. Parasitic helminths, worm species found in the phyla Nematoda and Platyhelminthes, are well‐recognised manipulators of host immune function and physiology. Emerging evidence supports a role for helminth‐derived EVs in these processes and highlights EVs as an important participant in cross‐phylum communication. While the mammalian EV field is guided by a community‐agreed framework for studying EVs derived from model organisms or cell systems [e.g., Minimal Information for Studies of Extracellular Vesicles (MISEV)], the helminth community requires a supplementary set of principles due to the additional challenges that accompany working with such divergent organisms. These challenges include, but are not limited to, generating sufficient quantities of EVs for descriptive or functional studies, defining pan‐helminth EV markers, genetically modifying these organisms, and identifying rigorous methodologies for in vitro and in vivo studies. Here, we outline best practices for those investigating the biology of helminth‐derived EVs to complement the MISEV guidelines. We summarise community‐agreed standards for studying EVs derived from this broad set of non‐model organisms, raise awareness of issues associated with helminth EVs and provide future perspectives for how progress in the field will be achieved