Biochemical Characterization of Echinococcus multilocularis Antigen B3 Reveals Insight into Adaptation and Maintenance of Parasitic Homeostasis at the Host-Parasite Interface

Targeted and non-targeted proteomics to characterize the parasite proteins of Echinococcus multilocularis metacestodes

The larval stage of the cestode Echinococcus multilocularis is the causative agent of alveolar echinococcosis. To investigate the biology of these stages and to test novel compounds, metacestode cultures represent a suitable in vitro model system. These metacestodes are vesicles surrounded by an envelope formed by the vesicle tissue (VT), which is formed by the laminated and germinal layer, and filled with vesicle fluid (VF). We analyzed the proteome of VF and VT by liquid chromatography tandem mass spectrometry (LC-MS/MS) and identified a total of 2,954 parasite proteins. The most abundant protein in VT was the expressed conserved protein encoded by EmuJ_000412500, followed by the antigen B subunit AgB8/3a encoded by EmuJ_000381500 and Endophilin B1 (protein p29). In VF, the pattern was different and dominated by AgB subunits. The most abundant protein was the AgB8/3a subunit followed by three other AgB subunits. In total, the AgB subunits detected in VF represented 62.1% of the parasite proteins. In culture media (CM), 63 E. multilocularis proteins were detected, of which AgB subunits made up 93.7% of the detected parasite proteins. All AgB subunits detected in VF (encoded by EmuJ_000381100-700, corresponding to AgB8/2, AgB8/1, AgB8/4, AgB8/3a, AgB8/3b, and AgB8/3c) were also found in CM, except the subunit encoded by EmuJ_000381800 (AgB8/5) that was very rare in VF and not detected in CM. The relative abundance of the AgB subunits in VF and CM followed the same pattern. In VT, only the subunits EmuJ_000381500 (AgB8/3a) and EmuJ_000381200 (AgB8/1) were detected among the 20 most abundant proteins. To see whether this pattern was specific to VF from in vitro cultured metacestodes, we analyzed the proteome of VF from metacestodes grown in a mouse model. Here, the AgB subunits encoded by EmuJ_000381100-700 constituted the most abundant proteins, namely, 81.9% of total protein, with the same order of abundance as in vitro. Immunofluorescence on metacestodes showed that AgB is co-localized to calcareous corpuscles of E. multilocularis. Using targeted proteomics with HA-tagged EmuJ_000381200 (AgB8/1) and EmuJ_000381100 (AgB8/2), we could show that uptake of AgB subunits from CM into VF occurs within hours.

Echinococcus granulosus Protoscolex DM9 Protein Shows High Potential for Serodiagnosis of Alveolar Echinococcosis

Alveolar echinococcosis (AE) caused by infection with E. multilocularis metacestode, represents one of the most fatal helminthic diseases. AE is principally manifested with infiltrative, proliferating hepatic mass, resembling primary hepatocellular carcinoma. Sometimes metastatic lesions are found in nearby or remote tissue. AE diagnosis largely depends on imaging studies, but atypical findings of imaging features frequently require differential diagnosis from other hepatic lesions. Serological tests may provide further evidence, while obtaining reliable AE materials is not easy. In this study, alternative antigens, specific to AE were identified by analyzing E. granulosus protoscolex proteins. An immunoblot analysis of E. granulosus protoscolex showed that a group of low-molecular-weight proteins in the range from 14 kDa to 16 kDa exhibited a sensitive and specific immune response to AE patient sera. Partial purification and proteomic analysis indicated that this protein group contained myosin, tubulin polymerization promoting protein, fatty-acid binding protein, uncharacterized DM9, heat shock protein 90 cochaperone tebp P-23, and antigen S. When the serological applicability of recombinant forms of these proteins was assessed using enzyme-linked immunosorbent assay, DM9 protein (rEgDM9) showed 90.1% sensitivity (73/81 sera tested) and 94.5% specificity (172/181 sera tested), respectively. rEgDM9 showed weak cross-reactions with patient sera from the transitional and chronic stages of cystic echinococcosis (3 to 5 stages). rEgDM9 would serve as a useful alternative antigen for serodiagnosis of both early- and advanced-stage AE cases.

Proteomic characterization of Echinococcus granulosus sensu stricto, Taenia hydatigena and Taenia multiceps metacestode cyst fluids

Cystic echinococcosis (CE) diagnosis by means of serological assays is hampered by the presence of parasites closely related to Echinococcus granulosus sensu lato (s.l.), responsible of the zoonotic disease and with which share cross-reacting antigens. Thus, improvements on the characterization of Echinococcus specific antigens expressed in the larval stage are required, in order to provide useful information for the development of immunological assays for the serodiagnosis of CE in sheep. Here, the proteome of the hydatid cyst fluids (HFs) of Echinococcus granulosus (hydatid fluid, EgHF) and other ovine parasites cyst fluids (CFs), Taenia hydatigena (ThCF) and Taenia multiceps (TmCF) were analyzed by a shotgun proteomic approach. Parasite and host protein profiles in the three types of cyst fluids were characterized and compared. Among the identified proteins, differential parasitic markers with serodiagnostic potential, due to their well-known immunoreactivity in human, included Ag5, AgB proteins, 8-kDa glycoproteins, hydatid disease diagnostic antigen P29 and major egg antigen P40. In particular, seven proteoforms of AgB and 8-kDa glycoprotein resulted to be the most promising diagnostic biomarkers, as they might predict CE in ovine and discriminate between different types of parasites.

Microcyst fluid promotes the migration and invasion of fibroblasts in the adventitial layer of alveolar echinococcosis

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis (E. multilocularis), characterized by lesions composed of an aggregate of microcysts embedded in a granulomatous host's reaction. The periphery of parasite granulomas often additionally displays fibrotic reactions of varying intensity, in which E. multilocularis microenvironment fibroblasts (EMFs) laid down collagen. However, the regulation of EMFs by the infiltration of E. multilocularis microcyst fluid (MF) into granulomas remains poorly defined. This study aimed to investigate the effect of MF on migration and invasion of primary isolated EMFs cells. A mouse model of secondary infection with AE was established, and the model construction was evaluated by HE staining. EMFs were cultured in primary by tissue block adherency method. The isolated cells were identified by qPCR, immunofluorescence and Western blot. Then CCK-8 assay, cell migration/invasion assay and flow cytometry were performed to detect the effects of MF on the proliferation, migration, invasion and cell cycle of EMFs, respectively. The expressions of MMP2 and MMP9 at mRNA and protein levels in EMFs were detected by RT-qPCR and Western blot. The effect of PI3K-Akt signal transduction pathway on regulating the expression of MMPs expression was assessed by Western blot. As indicated from the results, EMFs were successfully isolated from the E. multilocularis microenvironment and identified as myofibroblasts. MF significantly facilitated the proliferation and cell cycle progression of EMFs. In addition, MF significantly improved the migration and invasion of EMFs. MF was further confirmed to up-regulate mRNA and protein expressions of MMP2 and MMP9 in EMFs, which was related to the activation of the PI3K-Akt signaling pathway. The present study demonstrates that MF can promote the migration and invasion of EMFs cells significantly, which might be via activating PI3K-Akt signaling pathway.

Applied Proteomics in 'One Health'

‘One Health’ summarises the idea that human health and animal health are interdependent and bound to the health of ecosystems. The purpose of proteomics methodologies and studies is to determine proteins present in samples of interest and to quantify changes in protein expression during pathological conditions. The objectives of this paper are to review the application of proteomics technologies within the One Health concept and to appraise their role in the elucidation of diseases and situations relevant to One Health. The paper develops in three sections. Proteomics Applications in Zoonotic Infections part discusses proteomics applications in zoonotic infections and explores the use of proteomics for studying pathogenetic pathways, transmission dynamics, diagnostic biomarkers and novel vaccines in prion, viral, bacterial, protozoan and metazoan zoonotic infections. Proteomics Applications in Antibiotic Resistance part discusses proteomics applications in mechanisms of resistance development and discovery of novel treatments for antibiotic resistance. Proteomics Applications in Food Safety part discusses the detection of allergens, exposure of adulteration, identification of pathogens and toxins, study of product traits and characterisation of proteins in food safety. Sensitive analysis of proteins, including low-abundant ones in complex biological samples, will be achieved in the future, thus enabling implementation of targeted proteomics in clinical settings, shedding light on biomarker research and promoting the One Health concept.

Outcomes of Radiotherapy for Osseous Echinococcosis of Meriones meridianus

Background

Osseous cyst echinococcosis (CE) is an infectious disease that causes disability and deformity in patients, yet there is still no satisfactory treatment. Focusing on the feasibility and prognosis of radiotherapy as an adjuvant or palliative treatment for osseous CE, this study investigated the outcome of Meriones meridianus with osseous CE after radiotherapy.

Methods

The study utilized a comparison control group design with three groups of gerbils, and 240 osseous CE gerbils were randomly divided into control, 40Gy/5times, and 50Gy/5times groups. Different doses of radiotherapy were given to the gerbils, and then, the effects of radiotherapy on gerbils and lesions were observed at 3 and 6 months after radiotherapy. Statistical analysis was done using χ² test, unpaired t-test, and one-way ANOVA.

Results

Significant changes (P < 0.05) were achieved between the three groups in terms of seven parameters at 3 and 6 months, including the number of dead gerbils and lesion sites with ulceration and infection, number of dead scolices, protein content, Ca2+ concentration, the maximum diameter of lesion site, and wet weight of cysts. Except for the number of dead gerbils and lesion sites with ulceration and infection, all other parameters were observed a big difference between 3 months and 6 months in the 50Gy/5times group.

Conclusion

Radiotherapy at a dose of 50 Gy has inhibitory and therapeutic effects on osseous CE in gerbils, and radiotherapy could probably be a treatment option for persistent or recurrent osseous CE.

Comparative Transcriptomic Analysis of the Larval and Adult Stages of Taenia pisiformis

Taenia pisiformis is a tapeworm causing economic losses in the rabbit breeding industry worldwide. Due to the absence of genomic data, our knowledge on the developmental process of T. pisiformis is still inadequate. In this study, to better characterize differential and specific genes and pathways associated with the parasite developments, a comparative transcriptomic analysis of the larval stage (TpM) and the adult stage (TpA) of T. pisiformis was performed by Illumina RNA sequencing (RNA-seq) technology and de novo analysis. In total, 68,588 unigenes were assembled with an average length of 789 nucleotides (nt) and N50 of 1485 nt. Further, we identified 4093 differentially expressed genes (DEGs) in TpA versus TpM, of which 3186 DEGs were upregulated and 907 were downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes (KEGG) analyses revealed that most DEGs involved in metabolic processes and Wnt signaling pathway were much more active in the TpA stage. Quantitative real-time PCR (qPCR) validated that the expression levels of the selected 10 DEGs were consistent with those in RNA-seq, indicating that the transcriptomic data are reliable. The present study provides comparative transcriptomic data concerning two developmental stages of T. pisiformis, which will be of great value for future functional studies on the regulatory mechanisms behind adult worm pathogenesis and for developing drugs and vaccines against this important parasite.

Survey of echinococcoses in southeastern Qinghai Province, China, and serodiagnostic insights of recombinant Echinococcus granulosus antigen B isoforms

Background

Echinococcoses, caused by metacestodes of Echinococcus granulosus (cystic echinococcosis; CE) and E. multilocularis (alveolar echinococcosis; AE), represent major emerging parasitic diseases. These enzootic helminthiases invoke significant public health concerns and social burdens in endemic areas. The diseases are prevalent in the Qinghai-Tibetan Plateau, China, while community-based epidemiological studies have been scarcely reported. We surveyed echinococcosis patients in the southeastern Qinghai Province, China, to better understand the concurrent epidemiological situation in this area.

Methods

During July and August of 2013 and 2014, we screened echinococcosis patients at Yushu and Golog Prefectures, Qinghai Province, China, in a diagnostic campaign. A total of 2856 people (male:female ratio, 1:1.12; mean age, 34.6 years; age range, 6–88 years) were ultrasonographically examined for the presence of hepatic echinococcal cysts. We also collected serum samples from patients and analyzed antibody reactivity against recombinant forms of diverse E. granulosus antigen Bs (rEgAgB1-5) by enzyme-linked immunosorbent assay.

Results

We detected 134 patients whose imaging scans were compatible with CE (115 cases) and AE (20 patients). One patient might have been infected with both CE and AE. The overall incidence was 4.7% (CE, 4.0%; AE, 0.7%). A large proportion (67.5%) of CE patients was diagnosed at active and transitional CE1-CE3 stages in their late 30s. The AE cases were generally detected at advanced stage in patients at early 20s (60%). Analysis of the receiver operating characteristic curve and Youden’s index indicated that rEgAgB2 was the most promising biomarker, followed by rEgAgB3 and rEgAgB1. Overall, sensitivity and specificity of rEgAgB1-3 were 84.5–92.7% and 91.9–94.6%, respectively. rEgAgB4 and 5 showed low sensitivity with high cross-reactivity.

Conclusions

Our results strongly suggest that disability-adjusted life years related to echinococcoses in Qinghai-Tibetan areas might be more serious than previously considered. Control and prevention strategy against CE and AE are highly required in these areas. In addition to ultrasonography, serological tests might provide supportive data. However, serological data should be carefully interpreted for differential diagnosis, especially in areas where both CE and AE are co-endemic.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3569-6) contains supplementary material, which is available to authorized users.

Comparison of Echinococcus multilocularis and Echinococcus granulosus hydatid fluid proteome provides molecular strategies for specialized host-parasite interactions

Alveolar and cystic echinococcoses, caused by the metacestodes of Echinococcus multilocularis and E. granulosus, are prevalent in several regions and invoke deleterious zoonotic helminthiases. Hydatid fluid (HF), which contains proteinaceous and non-proteinaceous secretions of the parasite- and host-derived components, critically affects the host-parasite interplay and disease progression. We conducted HF proteome profiling of fully mature E. multilocularis vesicle (nine months postinfection) and E. granulosus cyst (stage 2). We identified 120 and 153 proteins, respectively, in each fluid. Fifty-six and 84 proteins represented distinct species; 44 and 66 were parasites, and 12 and 18 were host-derived proteins. The five major parasite protein populations, which included antigen B isoforms, metabolic enzymes, proteases and inhibitors, extracellular matrix molecules (ECMs), and developmental proteins, were abundantly distributed in both fluids and also exclusively in one sample or the other. Carbohydrate-metabolizing enzymes were enriched in E. granulosus HF. In the E. multilocularis HF, proteins that constitute ECMs, which might facilitate adhesion and cytogenesis, were highly expressed. Those molecules had physical and functional relationships along with their biochemical properties through protein-protein interaction networks. Twelve host-derived proteins were largely segregated to serum components. The major proteins commonly and uniquely detected in these HFs and their symbiotic interactome relationships might reflect their biological roles in similar but distinct modes of maturation, invasion, and the longevity of the parasites in the hosts.