An Open-Format Enteroid Culture System for Interrogation of Interactions Between Toxoplasma gondii and the Intestinal Epithelium

When transmitted through the oral route, Toxoplasma gondii first interacts with its host at the small intestinal epithelium. This interaction is crucial to controlling initial invasion and replication, as well as shaping the quality of the systemic immune response. It is therefore an attractive target for the design of novel vaccines and adjuvants. However, due to a lack of tractable infection models, we understand surprisingly little about the molecular pathways that govern this interaction. The in vitro culture of small intestinal epithelium as 3D enteroids shows great promise for modeling the epithelial response to infection. However, the enclosed luminal space makes the application of infectious agents to the apical epithelial surface challenging. Here, we have developed three novel enteroid-based techniques for modeling T. gondii infection. In particular, we have adapted enteroid culture protocols to generate collagen-supported epithelial sheets with an exposed apical surface. These cultures retain epithelial polarization, and the presence of fully differentiated epithelial cell populations. They are susceptible to infection with, and support replication of, T. gondii. Using quantitative label-free mass spectrometry, we show that T. gondii infection of the enteroid epithelium is associated with up-regulation of proteins associated with cholesterol metabolism, extracellular exosomes, intermicrovillar adhesion, and cell junctions. Inhibition of host cholesterol and isoprenoid biosynthesis with Atorvastatin resulted in a reduction in parasite load only at higher doses, indicating that de novo synthesis may support, but is not required for, parasite replication. These novel models therefore offer tractable tools for investigating how interactions between T. gondii and the host intestinal epithelium influence the course of infection

Determination of Giardia duodenalis assemblages and multi-locus genotypes in patients with sporadic giardiasis from England

BackgroundThe protozoan Giardia duodenalis is a common but highly diverse human parasite that comprises a complex of seven morphologically identical genetic assemblages, further divided into sub-assemblages. There is very little information available on the diversity of Giardia sub-assemblages and multi-locus genotypes infecting people in the United Kingdom. In this study we studied the molecular epidemiology of Giardia in symptomatic patients from North West England.MethodsWhole faecal DNA was extracted from the faecal samples of 406 Giardia cases and the parasites assemblage, sub-assemblage and multi-locus genotype were determined using PCR amplification, DNA sequencing and phylogenetic analysis of the beta-giardin, glutamate dehydrogenase, triose-phosphate isomerase and small-subunit ribosomal RNA genes. Information about age, gender and self-reported clinical outcomes was also collected from the patients to check for differences associated with the infecting Giardia assemblage.ResultsOur results showed a difference in the age prevalence of the two assemblages, with assemblage A being more common in older cases. Cases infected with assemblage B more often reported vomiting and a longer illness than cases infected with assemblage A. The majority of infections (64 %) were caused by assemblage B followed by assemblage A (33 %), while mixed-assemblage infections were rare (3 %). Assemblage A isolates mostly belonged to the sub-assemblage AII and showed completed identity with previously described isolates. The level of genetic sub-structuring was significantly higher in assemblage B isolates, since a higher proportion of novel assemblage B sequences was detected compared to assemblage A. A high number of assemblage B sequences showed heterogeneous nucleotide positions that prevented the unambiguous assignment to a specific sub-assemblage. Both previously described and novel multi-locus genotypes were described in both assemblages, and up to 17 different assemblage B multi-locus genotypes were found.ConclusionsWe have produced the first data on the parasite multi-locus genotypes in the UK and have demonstrated that the molecular diversity of Giardia is similar to other developed countries. Furthermore, we showed that the parasite assemblages infecting humans may be associated with patients of different ages and with different clinical outcomes

Toxoplasma gondii and Neospora caninum induce different host cell responses at proteome-wide phosphorylation events; a step forward for uncovering the biological differences between these closely related parasites

Toxoplasma gondii and Neospora caninum are closely related intracellular protozoan parasites and tissue cyst-forming Coccidia of the phylum Apicomplexa. There are remarkable similarities between the morphology, genomes and transcriptomes of both parasites. Toxoplasma is zoonotic, with a wide host range and is mainly transmitted horizontally between its definitive host, the cat, and its intermediate hosts. Neospora causes disease within a narrow host range and with reduced virulence potential to the hosts. The dog is the definitive host of Neospora and its epidemiology in cattle mainly depends on vertical transmission. What causes these biological differences is not well understood. Since these parasites secrete an array of secretory proteins, including kinases, during infection to manipulate host cell responses. Host-parasite interactions due to phosphorylation of host cell proteins by T. gondii kinases enhance virulence and maintenance of infection. In this study, proteome-wide phosphorylation events of host cell proteins were investigated in response to infection with T. gondii and N. caninum using phosphoproteomic analyses, followed by pathway analysis on host signalling pathways. A few interesting differences in host responses at both the qualitative and quantitative levels were identified between the two infections; about one third of the phosphoproteomes, approximately 21% of the phospho-motifs and several pathways such as glycolysis/gluconeogenesis and mTOR pathways of the host cell were found differentially enriched between infection with these parasites. Identifying the differences in host-parasite interactions represents a promising step forward for uncovering the biological dissimilarities between both parasites

Design for circular behaviour: Considering users in a circular economy

In a linear economy, a product is manufactured and sold to a customer. Then, little concern is given to what the user actually does with it when they have it. However, in a circular economy where the aim is to circulate products at their highest level of value, the customer’s behaviour can become an important part of the system. Circular design strategies have tended to focus on the physical aspects of a product (e.g., disassembly, material selection), but the design of products and services can also have an influence on user behaviour and, to date, this aspect of circular design has not been fully explored. This project aims to define what key user behaviours are required for circular business models to work and to outline how design can enable these ‘circular behaviours’. This research project consists of a literature review, case study analysis and expert interviews with practitioners. A theoretical framework for designing products and services to encourage circular behaviour is developed. This work provides an initial step towards a better understanding of the user’s role in the transition to a circular economy as well as a preliminary model for how design for behaviour change strategies could be implemented in this context

Integrative transcriptome and proteome analyses define marked differences between Neospora caninum isolates throughout the tachyzoite lytic cycle

Abstract Neospora caninum is one of the main causes of transmissible abortion in cattle. Intraspecific variations in virulence have been widely shown among N. caninum isolates. However, the molecular basis governing such variability have not been elucidated to date. In this study label free LC-MS/MS was used to investigate proteome differences between the high virulence isolate Nc-Spain7 and the low virulence isolate Nc-Spain1H throughout the tachyzoite lytic cycle. The results showed greater differences in the abundance of proteins at invasion and egress with 77 and 62 proteins, respectively. During parasite replication, only 19 proteins were differentially abundant between isolates. The microneme protein repertoire involved in parasite invasion and egress was more abundant in the Nc-Spain1H isolate, which displays a lower invasion rate. Rhoptry and dense granule proteins, proteins related to metabolism and stress responses also showed differential abundances between isolates. Comparative RNA-seq analyses during tachyzoite egress were also performed, revealing an expression profile of genes associated with the bradyzoite stage in the low virulence Nc-Spain1H isolate. The differences in proteome and RNA expression profiles between these two isolates reveal interesting insights into likely mechanisms involved in specific phenotypic traits and virulence in N. caninum. Significance The molecular basis that governs biological variability in N. caninum and the pathogenesis of neosporosis has not been well-established yet. This is the first study in which high throughput technology of LC-MS/MS and RNAseq is used to investigate differences in the proteome and transcriptome between two well-characterized isolates. Both isolates displayed different proteomes throughout the lytic cycle and the transcriptomes also showed marked variations but were inconsistent with the proteome results. However, both datasets identified a pre-bradyzoite status of the low virulence isolate Nc-Spain1H. This study reveals interesting insights into likely mechanisms involved in virulence in N. caninum and shed light on a subset of proteins that are potentially involved in the pathogenesis of this parasite

Unique Insights in the Cervicovaginal Lactobacillus iners and L. crispatus Proteomes and Their Associations with Microbiota Dysbiosis.

BACKGROUND: A Lactobacillus-dominated cervicovaginal microbiota (VMB) protects women from adverse reproductive health outcomes, but the role of L. iners in the VMB is poorly understood. Our aim was to explore the association between the cervicovaginal L. iners and L. crispatus proteomes and VMB composition. METHODS: The vaginal proteomes of 50 Rwandan women at high HIV risk, grouped into four VMB groups (based on 16S rDNA microarray results), were investigated by mass spectrometry using cervicovaginal lavage (CVL) samples. Only samples with positive 16S results for L. iners and/or L. crispatus within each group were included in subsequent comparative protein analyses: Lactobacillus crispatus-dominated VMB cluster (with 16S-proven L. iners (ni) = 0, and with 16S-proven L. crispatus (nc) = 5), L. iners-dominated VMB cluster (ni = 11, nc = 4), moderate dysbiosis (ni = 12, nc = 2); and severe dysbiosis (ni = 8, nc = 2). The relative abundances of proteins that were considered specific for L. iners and L. crispatus were compared among VMB groups. RESULTS: Forty Lactobacillus proteins were identified of which 7 were specific for L. iners and 11 for L. crispatus. The relative abundances of L. iners DNA starvation/stationary phase protection protein (DPS), and the glycolysis enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glucose-6-phosphate isomerase (GPI), were significantly decreased in women with L. iners-containing dysbiosis compared to women with a L. iners-dominated VMB, independent of vaginal pH and L. iners abundance. Furthermore, L. iners DPS, GAPDH, GPI, and fructose-bisphosphate aldolase (ALDO) were significantly negatively associated with vaginal pH. Glycolysis enzymes of L. crispatus showed a similar negative, but nonsignificant, trend related to dysbiosis. CONCLUSIONS: Most identified Lactobacillus proteins had conserved intracellular functions, but their high abundance in CVL supernatant might imply an additional extracellular (moonlighting) role. Our findings suggest that these proteins can be important in maintaining a Lactobacillus-dominated VMB. Functional studies are needed to investigate their roles in vaginal bacterial communities and whether they can be used to prevent vaginal dysbiosis

Giardia Secretome Highlights Secreted Tenascins as a Key Component of Pathogenesis

BackgroundGiardia is a protozoan parasite of public health relevance that causes gastroenteritis in a wide range of hosts. Two genetically distinct lineages (assemblages A and B) are responsible for the human disease. Although it is clear that differences in virulence occur, the pathogenesis and virulence of Giardia remain poorly understood.ResultsThe genome of Giardia is believed to contain open reading frames that could encode as many as 6000 proteins. By successfully applying quantitative proteomic analyses to the whole parasite and to the supernatants derived from parasite culture of assemblages A and B, we confirm expression of ~1600 proteins from each assemblage, the vast majority of which are common to both lineages. To look for signature enrichment of secreted proteins, we considered the ratio of proteins in the supernatant compared with the pellet, which defined a small group of enriched proteins, putatively secreted at a steady state by cultured growing trophozoites of both assemblages. This secretome is enriched with proteins annotated to have N-terminal signal peptide. The most abundant secreted proteins include known virulence factors such as cathepsin B cysteine proteases and members of a Giardia superfamily of cysteine-rich proteins that comprise variant surface proteins, high-cysteine membrane proteins, and a new class of virulence factors, the Giardia tenascins. We demonstrate that physiological function of human enteric epithelial cells is disrupted by such soluble factors even in the absence of the trophozoites.ConclusionsWe are able to propose a straightforward model of Giardia pathogenesis incorporating key roles for the major Giardia-derived soluble mediators

Dissecting the molecular diversity and commonality of bovine and human treponemes identifies key survival and adhesion mechanisms

Here, we report the first complete genomes of three cultivable treponeme species from bovine digital dermatitis (DD) skin lesions, two comparative human treponemes, considered indistinguishable from bovine DD species, and a bovine gastrointestinal (GI) treponeme isolate. Key genomic differences between bovine and human treponemes implicate microbial mechanisms that enhance knowledge of how DD, a severe disease of ruminants, has emerged into a prolific, worldwide disease. Bovine DD treponemes have additional oxidative stress genes compared to nearest human-isolated relatives, suggesting better oxidative stress tolerance, and potentially explaining how bovine strains can colonize skin surfaces. Comparison of both bovine DD and GI treponemes as well as bovine pathogenic and human non-pathogenic saprophyte Treponema phagedenis strains indicates genes encoding a five-enzyme biosynthetic pathway for production of 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid, a rare di-N-acetylated mannuronic acid sugar, as important for pathogenesis. Bovine T. phagedenis strains further differed from human strains by having unique genetic clusters including components of a type IV secretion system and a phosphate utilisation system including phoU, a gene associated with osmotic stress survival. Proteomic analyses confirmed bovine derived T. phagedenis exhibits expression of PhoU but not the putative secretion system, whilst the novel mannuronic acid pathway was expressed in near entirety across the DD treponemes. Analysis of osmotic stress response in water identified a difference between bovine and human T. phagedenis with bovine strains exhibiting enhanced survival. This novel mechanism could enable a selective advantage, allowing environmental persistence and transmission of bovine T. phagedenis. Finally, we investigated putative outer membrane protein (OMP) ortholog families across the DD treponemes and identified several families as multi-specific adhesins capable of binding extra cellular matrix (ECM) components. One bovine pathogen specific adhesin ortholog family showed considerable serodiagnostic potential with the Treponema medium representative demonstrating considerable disease specificity (91.6%). This work has shed light on treponeme host adaptation and has identified candidate molecules for future diagnostics, vaccination and therapeutic intervention

Proteomic Characterization of Host-Pathogen Interactions during Bovine Trophoblast Cell Line Infection by Neospora caninum.

Despite the importance of bovine neosporosis, relevant knowledge gaps remain concerning the pathogenic mechanisms of Neospora caninum. Infection of the placenta is a crucial event in the pathogenesis of the disease; however, very little is known about the relation of the parasite with this target organ. Recent studies have shown that isolates with important variations in virulence also show different interactions with the bovine trophoblast cell line F3 in terms of proliferative capacity and transcriptome host cell modulation. Herein, we used the same model of infection to study the interaction of Neospora with these target cells at the proteomic level using LC-MS/MS over the course of the parasite lytic cycle. We also analysed the proteome differences between high- (Nc-Spain7) and low-virulence (Nc-Spain1H) isolates. The results showed that mitochondrial processes and metabolism were the main points of Neospora-host interactions. Interestingly, Nc-Spain1H infection showed a higher level of influence on the host cell proteome than Nc-Spain7 infection

Library of Apicomplexan Metabolic Pathways: a manually curated database for metabolic pathways of apicomplexan parasites.

The Library of Apicomplexan Metabolic Pathways (LAMP, http://www.llamp.net) is a web database that provides near complete mapping from genes to the central metabolic functions for some of the prominent intracellular parasites of the phylum Apicomplexa. This phylum includes the causative agents of malaria, toxoplasmosis and theileriosis-diseases with a huge economic and social impact. A number of apicomplexan genomes have been sequenced, but the accurate annotation of gene function remains challenging. We have adopted an approach called metabolic reconstruction, in which genes are systematically assigned to functions within pathways/networks for Toxoplasma gondii, Neospora caninum, Cryptosporidium and Theileria species, and Babesia bovis. Several functions missing from pathways have been identified, where the corresponding gene for an essential process appears to be absent from the current genome annotation. For each species, LAMP contains interactive diagrams of each pathway, hyperlinked to external resources and annotated with detailed information, including the sources of evidence used. We have also developed a section to highlight the overall metabolic capabilities of each species, such as the ability to synthesize or the dependence on the host for a particular metabolite. We expect this new database will become a valuable resource for fundamental and applied research on the Apicomplexa