Parasite Extracellular Vesicles Research Articles

Microbial extracellular vesicles contribute to antimicrobial resistance.

With the escalating global antimicrobial resistance crisis, there is an urgent need for innovative strategies against drug-resistant microbes. Accumulating evidence indicates microbial extracellular vesicles (EVs) contribute to antimicrobial resistance. Therefore, comprehensively elucidating the roles and mechanisms of microbial EVs in conferring resistance could provide new perspectives and avenues for novel antimicrobial approaches. In this review, we systematically examine current research on antimicrobial resistance involving bacterial, fungal, and parasitic EVs, delineating the mechanisms whereby microbial EVs promote resistance. Finally, we discuss the application of bacterial EVs in antimicrobial therapy.

Eimeria falciformis extracellular vesicles differentially express host cell lncRNAs.

Long noncoding RNAs (lncRNAs) are regulatory transcripts during protozoan infections in the host intestinal epithelial cells (IECs). Apicomplexan Eimeria falciformis sporozoite extracellular vesicles (EVs) contain virulence factors that modulate host IECs pro-inflammatory genes and immune responses. In this study, E. falciformis sporozoites were made to interact with inactivated host cells, and the parasite EVs were separated from total secretome by ultracentrifugation and purified on density gradient medium. Dose-dependent bio-activity of E. falciformis EVs was investigated by RNA sequencing, functional annotation and quantitative PCR. It was found that E. falciformis EVs induced mRNA, circRNA, and lncRNA expressions in mouse IECs. Of 38, 217 lncRNAs assembled, 157 and 152 were upwardly and downwardly expressed respectively. Differentially expressed lncRNAs were associated with cytokines, pyroptosis, and immune signaling pathways including FoxO, NF-κB, MAPK, and TGF-β. In essence, E. falciformis EVs altered host cell RNA expressions during the interaction with host IECs. Also, differentially expressed lncRNAs are potential diagnostic transcripts during Eimeria infections.

Extracellular vesicles secreted by Echinococcus multilocularis: important players in angiogenesis promotion

The involvement of Echinococcus multilocularis, and other parasitic helminths, in regulating host physiology is well recognized, but molecular mechanisms remain unclear. Extracellular vesicles (EVs) released by helminths play important roles in regulating parasite-host interactions by transferring materials to the host. Analysis of protein cargo of EVs from E. multilocularis protoscoleces in the present study revealed a unique composition exclusively associated with vesicle biogenesis. Common proteins in various Echinococcus species were identified, including the classical EVs markers tetraspanins, TSG101 and Alix. Further, unique tegumental antigens were identified which could be exploited as Echinococcus EV markers. Parasite- and host-derived proteins within these EVs are predicted to support important roles in parasite–parasite and parasite-host communication. In addition, the enriched host-derived protein payloads identified in parasite EVs in the present study suggested that they can be involved in focal adhesion and potentially promote angiogenesis. Further, increased angiogenesis was observed in livers of mice infected with E. multilocularis and the expression of several angiogenesis-regulated molecules, including VEGF, MMP9, MCP-1, SDF-1 and serpin E1 were increased. Significantly, EVs released by the E. multilocularis protoscolex promoted proliferation and tube formation by human umbilical vein endothelial cells (HUVECs) in vitro. Taken together, we present the first evidence that tapeworm-secreted EVs may promote angiogenesis in Echinococcus-infections, identifying central mechanisms of Echinococcus-host interactions.

Insights on Host-Parasite Immunomodulation Mediated by Extracellular Vesicles of Cutaneous Leishmania shawi and Leishmania guyanensis.

Leishmaniasis is a parasitic disease caused by different species of Leishmania and transmitted through the bite of sand flies vector. Macrophages (MΦ), the target cells of Leishmania parasites, are phagocytes that play a crucial role in the innate immune microbial defense and are antigen-presenting cells driving the activation of the acquired immune response. Exploring parasite-host communication may be key in restraining parasite dissemination in the host. Extracellular vesicles (EVs) constitute a group of heterogenous cell-derived membranous structures, naturally produced by all cells and with immunomodulatory potential over target cells. This study examined the immunogenic potential of EVs shed by L. shawi and L. guyanensis in MΦ activation by analyzing the dynamics of major histocompatibility complex (MHC), innate immune receptors, and cytokine generation. L. shawi and L. guyanensis EVs were incorporated by MΦ and modulated innate immune receptors, indicating that EVs cargo can be recognized by MΦ sensors. Moreover, EVs induced MΦ to generate a mix of pro- and anti-inflammatory cytokines and favored the expression of MHCI molecules, suggesting that EVs antigens can be present to T cells, activating the acquired immune response of the host. Since nano-sized vesicles can be used as vehicles of immune mediators or immunomodulatory drugs, parasitic EVs can be exploited by bioengineering approaches for the development of efficient prophylactic or therapeutic tools for leishmaniasis.

New Biomarker in Chagas Disease: Extracellular Vesicles Isolated from Peripheral Blood in Chronic Chagas Disease Patients Modulate the Human Immune Response.

Chagas disease, a neglected tropical disease (NTD) caused by the flagellated protozoan Trypanosoma cruzi (T. cruzi), is a major public health problem. It was initially restricted to Latin America, but it is now expanding globally. Host and pathogen interactions are crucial in the establishment of disease, and since 1970, it has been known that eukaryotic cells release extracellular vesicles (EVs), which in turn have an important role in intercellular communication in physiological and pathological conditions. Our study proposed to characterize and compare circulating EVs isolated from the plasma of chronic Chagas disease (CCD) patients and controls. For this, peripheral blood was collected from patients and controls, and mononuclear cells (PBMCs) were isolated and stimulated with parasite EVs, showing that patient cells released fewer EVs than control cells. Then, after plasma separation followed by EV total shedding enrichment, the samples were subjected to ultracentrifugation to isolate the circulating EVs, which then had their size and concentration characterized by nanoparticle tracking analysis (NTA). This showed that patients had a lower concentration of circulating EVs while there were no differences in size, corroborating the in vitro data. Additionally, circulating EVs were incubated with THP-1 cells (macrophages) that, after the interaction, had their supernatant analyzed by ELISA for cytokine detection. In relation to their ability to induce cytokine production, the CCD patient EVs were able to induce a differential production of IFN-γ and IL-17 in relation to controls, with differences being more evident in earlier/less severe stages of the disease. In summary, a decreased concentration of circulating EVs associated with differential activation of the immunological system in patients with CCD is related to parasite persistence and the establishment of chronic disease. It is also a potential biomarker for monitoring disease progression.

Extracellular vesicles derived from Trichinella spiralis prevent colitis by inhibiting M1 macrophage polarization

Extracellular vesicles (EVs) are membranous containers released by cells that are powerful agents of intercellular communication. EVs have been described for various parasites and are associated with tissue inflammation. Several studies have demonstrated that parasite EVs can have either pro- or anti-inflammatory impacts, depending on the type of parasite. To evaluate the immunomodulatory properties of EVs produced by Trichinella spiralis (T. spiralis), we established a mouse model with dextran sulphate sodium (DSS)-induced colitis. The muscle larvae of T. spiralis were cultured in vitro and the released EVs were isolated by ultracentrifugation. T. spiralis EVs (Ts-EVs) were characterized according to morphology, size and constituent surface proteins (CD63, Enolase and Hsp70). Mice were treated with water containing 3% DSS after last intraperitoneal injection of Ts-EVs. Disease activity index (DAI), macroscopic and histopathological scores of Ts-EVs group was lower than DSS group. And Ts-EVs prevented the increase in the expression of TNF-α, IFN-γ, IL-17A and IL-1β observed in the colon of DSS-treated mice. In contrast, upregulation of IL-4, IL-10, TGF-β and IL-13 expression was detected in Ts-EVs+DSS group. In addition, Ts-EVs increased the infiltration of alternatively activated (M2) macrophages into the colon. The expression of CD206 (M2 marker) in the mesenteric lymph nodes (MLN) of mice with colitis increased in Ts-EVs+DSS group. Furthermore, Ts-EVs interfered with both the NF-κB and MAPK signalling pathways. Taken together, our findings demonstrate that Ts-EVs can affect the development of inflammation in DSS-induced colitis by inhibiting M1 macrophage polarization, due to their immunomodulatory ability.

Exploration of extracellular vesicles from Ascaris suum provides evidence of parasite–host cross talk

ABSTRACTThe prevalent porcine helminth, Ascaris suum, compromises pig health and reduces farm productivity worldwide. The closely related human parasite, A. lumbricoides, infects more than 800 million people representing a disease burden of 1.31 million disability-adjusted life years. The infections are often chronic in nature, and the parasites have a profound ability to modulate their hosts’ immune responses. This study provides the first in-depth characterisation of extracellular vesicles (EVs) from different developmental stages and body parts of A. suum and proposes the role of these vesicles in the host–parasite interplay. The release of EVs from the third- (L3) and fourth-stage (L4) larvae and adults was demonstrated by transmission electron microscopy (TEM), and sequencing of EV-derived RNA identified a number of microRNAs (miRNAs) and transcripts of potential host immune targets, such as IL-13, IL-25 and IL-33, were identified. Furthermore, proteomics of EVs identified several proteins with immunomodulatory properties and other proteins previously shown to be associated with parasite EVs. Taken together, these results suggest that A. suum EVs and their cargo may play a role in host–parasite interactions. This knowledge may pave the way to novel strategies for helminth infection control and knowledge of their immune modulatory potential.

Surface molecules of extracellular vesicles secreted by the helminth pathogen Fasciola hepatica direct their internalisation by host cells

Helminth parasites secrete extracellular vesicles (EVs) that can be internalised by host immune cells resulting in modulation of host immunity. While the molecular cargo of EVs have been characterised in many parasites, little is known about the surface-exposed molecules that participate in ligand-receptor interactions with the host cell surface to initiate vesicle docking and subsequent internalisation. Using a membrane-impermeable biotin reagent to capture proteins displayed on the outer membrane surface of two EV sub-populations (termed 15k and 120k EVs) released by adult F. hepatica, we describe 380 surface proteins including an array of virulence factors, membrane transport proteins and molecules involved in EV biogenesis/trafficking. Proteomics and immunohistochemical analysis show that the 120k EVs have an endosomal origin and may be released from the parasite via the protonephridial (excretory) system whilst the larger 15k EVs are released from the gastrodermal epithelial cells that line the fluke gut. A parallel lectin microarray strategy was used to profile the topology of major surface oligosaccharides of intact fluorogenically-labelled EVs as they would be displayed to the host. Lectin profiles corresponding to glycoconjugates exposed on the surface of the 15 K and 120K EV sub-populations are practically identical but are distinct from those of the parasite surface tegument, although all are predominated by high mannose sugars. We found that while the F. hepatica EVs were resistant to exo- and endo-glycosidases, the glyco-amidase PNGase F drastically remodelled the surface oligosaccharides and blocked the uptake of EVs by host macrophages. In contrast, pre-treatment with antibodies obtained from infected hosts, or purified antibodies raised against the extracellular domains of specific EV surface proteins (DM9-containing protein, CD63 receptor and myoferlin), significantly enhanced their cellular internalisation. This work highlights the diversity of EV biogenesis and trafficking pathways used by F. hepatica and sheds light on the molecular interaction between parasite EVs and host cells.

Rapid Differentiation of Host and Parasitic Exosome Vesicles Using Microfluidic Photonic Crystal Biosensor.

Parasite extracellular vesicles (EVs) are potential biomarkers that could be exploited for the diagnosis of infectious disease. This paper reports a rapid bioassay to discriminate parasite and host EVs. The EV detection assay utilizes a label-free photonic crystal (PC) biosensor to detect the EVs using a host-specific transmembrane protein (CD63), which is present on EV secreted by host cells (modeled by murine macrophage cell line J774A.1) but is not expressed on EV secreted by parasitic nematodes such as the gastrointestinal nematode Ascaris suum. The surface of PC is functionalized to recognize CD63, and is sensitive to the changes in refractive index caused by the immobilization of EVs. The biosensor demonstrates a detection limit of 2.18 × 109 EVs/mL and a capability to characterize the affinity constants of antibody-host EV bindings. The discrimination of murine host EVs from parasite EVs indicates the capability of the sensor to differentiate EVs from different origins. The label-free, rapid EV assay could be used to detection parasite infection and facilitate the exosome-based clinic diagnosis and exosome research.

Parasite extracellular vesicles: mediators of intercellular communication.

The 2013 Nobel Prize in Physiology or Medicine recognized pioneering research on secretion of proteins outside the cell and the delivery of selected cargo to specific intracellular compartments via secretory vesicles. This seminal work, performed in yeast and mammalian cells, defined multiple vital roles vesicles play in cellular physiology. Recent studies have revealed the critical role of vesicles in intercellular communication. Here, we provide an overview of eukaryotic parasite-associated extracellular vesicles (EVs). Their contribution to host–pathogen interactions and possible use in vaccine design and disease diagnosis is discussed.