Comparative Proteomics Analysis of Anisakis simplex s.s.-Evaluation of the Response of Invasive Larvae to Ivermectin

Integrated transcriptomic and proteomic analyses of plerocercoid and adult Spirometra mansoni reveal potential important pathways in the development of the medical tapeworm

BACKGROUND

Spirometra mansoni can parasitize animals and humans through food and water, causing parasitic zoonosis. Knowledge of the developmental process of S. mansoni is crucial for effective treatment; thus, it is important to characterize differential and specific proteins and pathways associated with parasite development.

METHODS

In this study, we performed a comparative proteomic analysis of the plerocercoid and adult stages using a tandem mass tag-based quantitative proteomic approach. Additionally, integrated transcriptomic and proteomic analyses were conducted to obtain the full protein expression profiles of different life cycle stages of the tapeworm.

RESULTS

Approximately 1166 differentially expressed proteins (DEPs) were identified in adults versus plerocercoids, of which 641 DEPs were upregulated and 525 were downregulated. Gene Ontology (GO), Clusters of Orthologous groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that most DEPs related to genetic information processing and metabolism of energy in adults seem to be more activated. In the plerocercoid stage, compared to metabolism, genetic information processing appears more dynamic. Protein-protein interaction (PPI) revealed six key proteins (phosphomannomutase, glutathione transferase, malate dehydrogenase, cytoplasmic, 40S ribosomal protein S15, ribosomal protein L15 and 60S acidic ribosomal protein P2) that may play active roles in the growth and development of S. mansoni. Finally, the combination of transcriptomic and proteomic data suggested that three pathways (ubiquitin-mediated proteolysis, phagosome and spliceosome) and five proteins closely related to these pathways might have a significant influence in S. mansoni.

CONCLUSIONS

These findings contribute to increasing the knowledge on the protein expression profiles of S. mansoni and provide new insights into functional studies on the molecular mechanisms of the neglected medical tapeworm.

Metabolomic analysis reveals a differential adaptation process of the larval stages of Anisakis simplex to the host environment

Introduction: Anisakis simplex are parasitic nematodes that cause anisakiasis. The possibility of infection with this parasite is through consumption of raw or undercooked fish products. A. simplex infections are often misdiagnosed, especially in subclinical cases that do not present with typical symptoms such as urticaria, angioedema, and gastrointestinal allergy. The resulting allergic reactions range from rapid-onset and potentially fatal anaphylactic reactions to chronic, debilitating conditions. While there have been numerous published studies on the genomes and proteomes of A. simplex, less attention has been paid to the metabolomes. Metabolomics is concerned with the composition of metabolites in biological systems. Dynamic responses to endogenous and exogenous stimuli are particularly well suited for the study of holistic metabolic responses. In addition, metabolomics can be used to determine metabolic activity at different stages of development or during growth. Materials and methods: In this study, we reveal for the first time the metabolomes of infectious stages (L3 and L4) of A. simplex using untargeted metabolomics by ultra-performance liquid chromatography-mass spectrometry. Results: In the negative ionization mode (ESI-), we identified 172 different compounds, whereas in the positive ionization mode (ESI+), 186 metabolites were found. Statistical analysis showed that 60 metabolites were found in the ESI- mode with different concentration in each group, of which 21 were more enriched in the L3 larvae and 39 in the L4 stage of A. simplex. Comparison of the individual developmental stages in the ESI + mode also revealed a total of 60 differential metabolites, but 32 metabolites were more enriched in the L3 stage larvae, and 28 metabolites were more concentrated in the L4 stage. Discussion: The metabolomics study revealed that the developmental stages of A. simplex differed in a number of metabolic pathways, including nicotinate and nicotinamide metabolism. In addition, molecules responsible for successful migration within their host, such as pyridoxine and prostaglandins (E1, E2, F1a) were present in the L4 stage. In contrast, metabolic pathways for amino acids, starch, and sucrose were mainly activated in the L3 stage. Our results provide new insights into the comparative metabolome profiles of two different developmental stages of A. simplex.

Drug efficacy on zoonotic nematodes of the Anisakidae family - new metabolic data

In the Anisakidae family, there are nematodes, most of which are parasitic for important commercial fish species. Both public health risks and socio-economic problems are attributed to these parasites. Despite these concerns, knowledge of the metabolism of these parasites remains unknown. Therefore, the main objective of this study was to investigate the receptors of drugs and oxidative metabolic status of two Anisakidae species, Pseudoterranova decipiens (s. s.) and Contracaecum osculatum (s. s.), under the influence of anthelminthic drugs, ivermectin (IVM) and pyrantel (PYR), at different concentrations: 1.56, 3.125 and 6.25 μg mL⁻¹ of culture medium for 3, 6, 9, 12 and 72 h. The mRNA expressions of the γ-aminobutyric acid receptor, acetylcholine receptor subunits, adenosine triphosphate-binding cassette transporters and antioxidative enzymes were determined. The total antioxidant capacity and glutathione S-transferase activity were also examined. To the best of the authors' knowledge, this is the first time that IVM and PYR have been tested against these parasitic nematodes.

Tandem Mass Tagging (TMT) Reveals Tissue-Specific Proteome of L4 Larvae of Anisakis simplex s. s.: Enzymes of Energy and/or Carbohydrate Metabolism as Potential Drug Targets in Anisakiasis

Anisakis simplex s. s. is a parasitic nematode of marine mammals and causative agent of anisakiasis in humans. The cuticle and intestine of the larvae are the tissues most responsible for direct and indirect contact, respectively, of the parasite with the host. At the L4 larval stage, tissues, such as the cuticle and intestine, are fully developed and functional, in contrast to the L3 stage. As such, this work provides for the first time the tissue-specific proteome of A. simplex s. s. larvae in the L4 stage. Statistical analysis (FC ≥ 2; p-value ≤ 0.01) showed that 107 proteins were differentially regulated (DRPs) between the cuticle and the rest of the larval body. In the comparison between the intestine and the rest of the larval body at the L4 stage, 123 proteins were identified as DRPs. Comparison of the individual tissues examined revealed a total of 272 DRPs, with 133 proteins more abundant in the cuticle and 139 proteins more abundant in the intestine. Detailed functional analysis of the identified proteins was performed using bioinformatics tools. Glycolysis and the tricarboxylic acid cycle were the most enriched metabolic pathways by cuticular and intestinal proteins, respectively, in the L4 stage of A. simplex s. s. The presence of two proteins, folliculin (FLCN) and oxoglutarate dehydrogenase (OGDH), was confirmed by Western blot, and their tertiary structure was predicted and compared with other species. In addition, host–pathogen interactions were identified, and potential new allergens were predicted. The result of this manuscript shows the largest number of protein identifications to our knowledge using proteomics tools for different tissues of L4 larvae of A. simplex s. s. The identified tissue-specific proteins could serve as targets for new drugs against anisakiasis.

Proteomic Profiling and In Silico Characterization of the Secretome of Anisakis simplex Sensu Stricto L3 Larvae

Anisakis simplex sensu stricto (s.s.) L3 larvae are one of the major etiological factors of human anisakiasis, which is one of the most important foodborne parasitic diseases. Nevertheless, to date, Anisakis secretome proteins, with important functions in nematode pathogenicity and host-parasite interactions, have not been extensively explored. Therefore, the aim of this study was to identify and characterize the excretory-secretory (ES) proteins of A. simplex L3 larvae. ES proteins of A. simplex were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the identified proteins were then analyzed using bioinformatics tools. A total of 158 proteins were detected. Detailed bioinformatic characterization of ES proteins was performed, including Gene Ontology (GO) analysis, identification of enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, protein family classification, secretory pathway prediction, and detection of essential proteins. Furthermore, of all detected ES proteins, 1 was identified as an allergen, which was Ani s 4, and 18 were potential allergens, most of which were homologs of nematode and arthropod allergens. Nine potential pathogenicity-related proteins were predicted, which were predominantly homologs of chaperones. In addition, predicted host-parasite interactions between the Anisakis ES proteins and both human and fish proteins were identified. In conclusion, this study represents the first global analysis of Anisakis ES proteins. The findings provide a better understanding of survival and invasion strategies of A. simplex L3 larvae.

A Complex Proteomic Response of the Parasitic Nematode Anisakis simplex s.s. to Escherichia coliLipopolysaccharide

Helminths are masters at manipulating host's immune response. Especially, parasitic nematodes have evolved strategies that allow them to evade, suppress, or modulate host's immune response to persist and spread in the host's organism. While the immunomodulatory effects of nematodes on their hosts are studied with a great commitment, very little is known about nematodes' own immune system, immune response to their pathogens, and interactions between parasites and bacteria in the host's organism. To illustrate the response of the parasitic nematode Anisakis simplex s.s. during simulated interaction with Escherichia coli, different concentrations of lipopolysaccharide (LPS) were used, and the proteomic analysis with isobaric mass tags for relative and absolute quantification (tandem mass tag-based LC-MS/MS) was performed. In addition, gene expression and biochemical analyses of selected markers of oxidative stress were determined. The results revealed 1148 proteins in a group of which 115 were identified as differentially regulated proteins, for example, peroxiredoxin, thioredoxin, and macrophage migration inhibitory factor. Gene Ontology annotation and Reactome pathway analysis indicated that metabolic pathways related to catalytic activity, oxidation-reduction processes, antioxidant activity, response to stress, and innate immune system were the most common, in which differentially regulated proteins were involved. Further biochemical analyses let us confirm that the LPS induced the oxidative stress response, which plays a key role in the innate immunity of parasitic nematodes. Our findings, to our knowledge, indicate for the first time, the complexity of the interaction of parasitic nematode, A. simplex s.s. with bacterial LPS, which mimics the coexistence of helminth and gut bacteria in the host. The simulation of this crosstalk led us to conclude that the obtained results could be hugely valuable in the integrated systems biology approach to describe a relationship between parasite, host, and its commensal bacteria.

Proteomic Insights into the Biology of the Most Important Foodborne Parasites in Europe

Foodborne parasitoses compared with bacterial and viral-caused diseases seem to be neglected, and their unrecognition is a serious issue. Parasitic diseases transmitted by food are currently becoming more common. Constantly changing eating habits, new culinary trends, and easier access to food make foodborne parasites' transmission effortless, and the increase in the diagnosis of foodborne parasitic diseases in noted worldwide. This work presents the applications of numerous proteomic methods into the studies on foodborne parasites and their possible use in targeted diagnostics. Potential directions for the future are also provided.

Proteomics-Based Methodologies for the Detection and Quantification of Seafood Allergens

Seafood is considered one of the main food allergen sources by the European Food Safety Authority (EFSA). It comprises several distinct groups of edible aquatic animals, including fish and shellfish, such as crustacean and mollusks. Recently, the EFSA recognized the high risk of food allergy over the world and established the necessity of developing new methodologies for its control. Consequently, accurate, sensitive, and fast detection methods for seafood allergy control and detection in food products are highly recommended. In this work, we present a comprehensive review of the applications of the proteomics methodologies for the detection and quantification of seafood allergens. For this purpose, two consecutive proteomics strategies (discovery and targeted proteomics) that are applied to the study and control of seafood allergies are reviewed in detail. In addition, future directions and new perspectives are also provided.

Quantitative Proteomics Comparison of Total Expressed Proteomes of Anisakis simplex Sensu Stricto, A. pegreffii, and Their Hybrid Genotype

The total proteomes of Anisakis simplex s.s., A. pegreffii and their hybrid genotype have been compared by quantitative proteomics (iTRAQ approach), which considers the level of expressed proteins. Comparison was made by means of two independent experiments considering four biological replicates of A. simplex and two each for A. pegreffii and hybrid between both species. A total of 1811 and 1976 proteins have been respectively identified in the experiments using public databases. One hundred ninety-six proteins were found significantly differentially expressed, and their relationships with the nematodes' biological replicates were estimated by a multidimensional statistical approach. Results of pairwise Log2 ratio comparisons among them were statistically treated and supported in order to convert them into discrete character states. Principal component analysis (PCA) confirms the validity of the method. This comparison selected thirty seven proteins as discriminant taxonomic biomarkers among A. simplex, A. pegreffii and their hybrid genotype; 19 of these biomarkers, encoded by ten loci, are specific allergens of Anisakis (Ani s7, Ani s8, Ani s12, and Ani s14) and other (Ancylostoma secreted) is a common nematodes venom allergen. The rest of the markers comprise four unknown or non-characterized proteins; five different proteins (leucine) related to innate immunity, four proteolytic proteins (metalloendopeptidases), a lipase, a mitochondrial translocase protein, a neurotransmitter, a thyroxine transporter, and a structural collagen protein. The proposed methodology (proteomics and statistical) solidly characterize a set of proteins that are susceptible to take advantage of the new targeted proteomics.