Comparative analysis of iTRAQ-based proteome profiles of Schistosoma japonicum female worms coming from single-sex infections and bisexual infections

Functional characterization of differentially expressed proteins coming from unisexual and bisexual infected Schistosoma japonicum female worms

Schistosomiasis is an important zoonotic disease affecting up to 40 kinds of animals and is responsible for ∼250 million human cases per year. Due to the extensive use of praziquantel for the treatment of parasitic diseases, drug resistance has been reported. Consequently, novel drugs and effective vaccines are urgently needed for sustained control of schistosomiasis. Targeting reproductive development of Schistosoma japonicum could contribute to the control of schistosomiasis. In this study, five highly expressed proteins (S. japonicum large subunit ribosomal protein L7e, S. japonicum glutathione S-transferase class-mu 26 kDa isozyme, S. japonicum UDP-galactose-4-epimerase and two hypothetical proteins SjCAX70849 and SjCAX72486) in 18, 21, 23, and 25-day mature female worms compared to single-sex infected female worms were selected based on our previous proteomic analysis. Quantitative real-time polymerase chain reaction analysis and long-term interference with small interfering RNA were performed to identify the biological functions of these five proteins. The transcriptional profiles suggested that all five proteins participated in the maturation of S. japonicum. RNA interference against these proteins resulted in morphological changes to S. japonicum. The results of an immunoprotection assay revealed that immunization of mice with recombinant SjUL-30 and SjCAX72486 upregulated production of immunoglobulin G-specific antibodies. Collectively, the results demonstrated that these five differentially expressed proteins were vital to reproduction of S. japonicum and, thus, are potential candidate antigens for immune protection against schistosomiasis.

Inhibition of signal peptidase complex expression affects the development and survival of Schistosoma japonicum

Background

Schistosomiasis, the second most neglected tropical disease defined by the WHO, is a significant zoonotic parasitic disease infecting approximately 250 million people globally. This debilitating disease has seriously threatened public health, while only one drug, praziquantel, is used to control it. Because of this, it highlights the significance of identifying more satisfactory target genes for drug development. Protein translocation into the endoplasmic reticulum (ER) is vital to the subsequent localization of secretory and transmembrane proteins. The signal peptidase complex (SPC) is an essential component of the translocation machinery and functions to cleave the signal peptide sequence (SP) of secretory and membrane proteins entering the ER. Inhibiting the expression of SPC can lead to the abolishment or weaker cleavage of the signal peptide, and the accumulation of uncleaved protein in the ER would affect the survival of organisms. Despite the evident importance of SPC, in vivo studies exploring its function have yet to be reported in S. japonicum.

Methods

The S. japonicum SPC consists of four proteins: SPC12, SPC18, SPC22 and SPC25. RNA interference was used to investigate the impact of SPC components on schistosome growth and development in vivo. qPCR and in situ hybridization were applied to localize the SPC25 expression. Mayer's carmalum and Fast Blue B staining were used to observe morphological changes in the reproductive organs of dsRNA-treated worms. The effect of inhibitor treatment on the worm's viability and pairing was also examined in vitro.

Results

Our results showed that RNAi-SPC delayed the worm's normal development and was even lethal for schistosomula in vivo. Among them, the expression of SPC25 was significantly higher in the developmental stages of the reproductive organs in schistosomes. Moreover, SPC25 possessed high expression in the worm tegument, testes of male worms and the ovaries and vitellarium of female worms. The SPC25 knockdown led to the degeneration of reproductive organs, such as the ovaries and vitellarium of female worms. The SPC25 exhaustion also reduced egg production while reducing the pathological damage of the eggs to the host. Additionally, the SPC-related inhibitor AEBSF or suppressing the expression of SPC25 also impacted cultured worms' pairing and viability in vitro.

Conclusions

These data demonstrate that SPC is necessary to maintain the development and reproduction of S. japonicum. This research provides a promising anti-schistosomiasis drug target and discovers a new perspective on preventing worm fecundity and maturation.

Single-sex schistosomiasis: a mini review

Schistosomiasis is a neglected tropical disease caused by dioecious blood flukes of the genus Schistosoma and second to malaria as a parasitic disease with significant socio-economic impacts. Mating is essential for maturation of male and female schistosomes and for females to lay of eggs, which are responsible for the pathogenesis and propagation of the life cycle beyond the mammalian host. Single-sex schistosomes, which do not produce viable eggs without mating, have been overlooked given the symptomatic paucity of the single-sex schistosomiasis and limited diagnostic toolkit. Besides, single-sex schistosomes are less sensitive to praziquantel. Therefore, these issues should be considered to achieve the elimination of this infection disease. The aim of this review is to summarize current progress in research of single-sex schistosomes and host-parasite interactions.

Comparative proteomic profiles of Schistosoma japonicum male worms derived from single-sex and bisexual infections

Schistosomiasis, which is caused by parasitic schistosomes, remains the second most prevalent parasitic disease of mammals worldwide. To successfully maintain fecundity, schistosomes have evolved a lifecycle that involves the cooperation of morphologically distinct male and female forms. Eggs produced by worm pairs are vital to the lifecycle of the parasite and are responsible for pathogenesis. Understanding the reproductive mechanism of schistosomes will help to control infection. In this study, the proteomic profiles of single-sex infected male (SM) worms and bisexual infected mated male (MM) worms of Schistosoma japonicum at 18, 21, 23, and 25 days p.i. were identified through data-independent acquisition. In total, 674 differentially expressed proteins (DEPs) were identified for the SM and MM worms at all four timepoints. Bioinformatic analysis demonstrated that most of the DEPs were involved in biosynthetic processes including locomotion, cell growth and death, cell motility, and metabolic processes such as protein metabolism and glucose metabolism. Schistosoma japonicum glycosyltransferase (SjGT) and S. japonicum nicastrin protein (SjNCSTN) were selected for quantitative real‑time PCR analysis and long-term interference with small interfering RNA (siRNA) to further explore the functions of the DEPs. Sjgt mRNA expression was mainly enriched in male worms, while Sjncstn was enriched in both sexes. siRNA against SjGT and SjNCSTN resulted in minor morphological changes in the testes of male worms and significant decreased vitality and fertility. The present study provides comprehensive proteomic profiles of S. japonicum SM and MM worms at 18, 21, 23, and 25 days p.i. and offers insights into the mechanisms underlying the growth and maturation of schistosomes.

Molecular insights into the heat shock proteins of the human parasitic blood fluke Schistosoma mansoni

Background

Heat shock proteins (HSPs) are evolutionarily conserved proteins, produced by cells in response to hostile environmental conditions, that are vital to organism homeostasis. Here, we undertook the first detailed molecular bioinformatic analysis of these important proteins and mapped their tissue expression in the human parasitic blood fluke, Schistosoma mansoni, one of the causative agents of the neglected tropical disease human schistosomiasis.

Methods

Using bioinformatic tools we classified and phylogenetically analysed HSP family members in schistosomes, and performed transcriptomic, phosphoproteomic, and interactomic analysis of the S. mansoni HSPs. In addition, S. mansoni HSP protein expression was mapped in intact parasites using immunofluorescence.

Results

Fifty-five HSPs were identified in S. mansoni across five HSP families; high conservation of HSP sequences were apparent across S. mansoni, Schistosoma haematobium and Schistosoma japonicum, with S. haematobium HSPs showing greater similarity to S. mansoni than those of S. japonicum. For S. mansoni, differential HSP gene expression was evident across the various parasite life stages, supporting varying roles for the HSPs in the different stages, and suggesting that they might confer some degree of protection during life stage transitions. Protein expression patterns of HSPs were visualised in intact S. mansoni cercariae, 3 h and 24 h somules, and adult male and female worms, revealing HSPs in the tegument, cephalic ganglia, tubercles, testes, ovaries as well as other important organs. Analysis of putative HSP protein-protein associations highlighted proteins that are involved in transcription, modification, stability, and ubiquitination; functional enrichment analysis revealed functions for HSP networks in S. mansoni including protein export for HSP 40/70, and FOXO/mTOR signalling for HSP90 networks. Finally, a total of 76 phosphorylation sites were discovered within 17 of the 55 HSPs, with 30 phosphorylation sites being conserved with those of human HSPs, highlighting their likely core functional significance.

Conclusions

This analysis highlights the fascinating biology of S. mansoni HSPs and their likely importance to schistosome function, offering a valuable and novel framework for future physiological investigations into the roles of HSPs in schistosomes, particularly in the context of survival in the host and with the aim of developing novel anti-schistosome therapeutics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05500-7.

Proteomics Investigations of Potential Protein Biomarkers in Sera of Rabbits Infected With Schistosoma japonicum

Schistosomiasis is a chronic parasitic disease that continues to be a pressing public health problem in many developing countries. The primary pathological damage from the disease is granuloma and fibrosis caused by egg aggregation, and early treatment can effectively prevent the occurrence of liver fibrosis. Therefore, it is very important to identify biomarkers that can be used for early diagnosis of Schistosoma japonicum infection. In this study, a label-free proteomics method was performed to observe the alteration of proteins before infection, 1 and 6 weeks after infection, and 5 and 7 weeks after treatment. A total of 10 proteins derived from S. japonicum and 242 host-derived proteins were identified and quantified as significantly changed. Temporal analysis was carried out to further analyze potential biomarkers with coherent changes during infection and treatment. The results revealed biological process changes in serum proteins compared to infection and treatment groups, which implicated receptor-mediated endocytosis, inflammatory response, and acute-phase response such as mannan-binding lectin serine peptidase 1, immunoglobulin, and collagen. These findings offer guidance for the in-depth analysis of potential biomarkers of schistosomiasis, host protein, and early diagnosis of S. japonicum and its pathogenesis. Data are available via ProteomeXchange with identifier PXD029635.

OUP accepted manuscript

The mutations in modifier genes may contribute to some inherited diseases including Wilson disease (WD). This study was designed to identify potential modifier genes that contribute to WD. A total of 10 WD patients with single or no heterozygous ATP7B mutations were recruited for whole-exome sequencing (WES). Five hundred and thirteen candidate genes, of which the genetic variants present in at least two patients, were identified. In order to clarify which proteins might be involved in copper transfer or metabolism processes, the isobaric tags for relative and absolute quantitation (iTRAQ) was performed to identify the differentially expressed proteins between normal and CuSO₄-treated cell lines. Thirteen genes/proteins were identified by both WES and iTRAQ, indicating that disease-causing variants of these genes may actually contribute to the aberrant copper ion accumulation. Additionally, the c.86C > T (p.S29L) mutation in the SLC31A2 gene (coding CTR2) has a relative higher frequency in our cohort of WD patients (6/191) than reported (0.0024 in gnomAD database) in our healthy donors (0/109), and CTR2^S29L leads to increased intracellular Cu concentration and Cu-induced apoptosis in cultured cell lines. In conclusion, the WES and iTRAQ approaches successfully identified several disease-causing variants in potential modifier genes that may be involved in the WD phenotype.

iTRAQ and PRM-Based Proteomic Analysis Provides New Insights into Mechanisms of Response to Triple Therapy in Patients with Rheumatoid Arthritis

Background

Approximately 30% of patients with rheumatoid arthritis (RA) respond poorly to combination therapy of multiple drugs. The molecular mechanisms of different responses to methotrexate + leflunomide + infliximab therapy in patients with RA were explored in this study.

Methods

Infliximab was administered to patients with RA whose disease activity score was higher than 5.1 after 1 month of combination therapy with methotrexate and leflunomide. After 14 weeks of undergoing triple therapy, patients with RA were classified as responders and non-responders. Protein profiles at baseline and 14th week were investigated via isobaric tags for relative and absolute quantification (iTRAQ), and proteins with significant differences ≥1.2 folds change or ≤0.8 folds change were defined as differentially expressed proteins (DEPs). Overlapping DEPs between responders and non-responders were confirmed by parallel reaction monitoring (PRM). Bioinformatic analyses were performed for DEPs.

Results

The results revealed 5 non-responders (NRs) and 15 responders (Rs). iTRAQ analysis indicated 13 overlapping DEPs and included 6 opposite change DEPs such as testicular tissue protein Li 70, cofilin 1, fibrinogen beta chain, galectin-10, serotransferrin (TF) and albumin. The difference in serotransferrin between responders and non-responders confirmed by PRM was significant. Verification by PRM indicated that TF was elevated in the Rs group and was reduced in the NRs group. Bioinformatic analysis indicated that serotransferrin was involved in the hypoxia-inducible factor-1 pathway and ferroptosis.

Conclusion

Serotransferrin-related molecular mechanism may be a new direction to study refractory RA.

Trematode Proteomics: Recent Advances and Future Directions

Trematodes cause disease in millions of people worldwide, but the absence of commercial vaccines has led to an over-reliance on a handful of monotherapies to control infections. Since drug-resistant fluke populations are emerging, a deeper understanding of parasite biology and host interactions is required to identify new drug targets and immunogenic vaccine candidates. Mass spectrometry-based proteomics represents a key tool to that end. Recent studies have capitalised on the wider availability of annotated helminth genomes to achieve greater coverage of trematode proteomes and discover new aspects of the host-parasite relationship. This review focusses on these latest advances. These include how the protein components of fluke extracellular vesicles have given insight into their biogenesis and cellular interactions. In addition, how the integration of transcriptome/proteome datasets has revealed that the expression and secretion of selected families of liver fluke virulence factors and immunomodulators are regulated in accordance with parasite development and migration within the mammalian host. Furthermore, we discuss the use of immunoproteomics as a tool to identify vaccine candidates associated with protective antibody responses. Finally, we highlight how established and emerging technologies, such as laser microdissection and single-cell proteomics, could be exploited to resolve the protein profiles of discrete trematode tissues or cell types which, in combination with functional tools, could pinpoint optimal targets for fluke control.

iTRAQ-based comparative proteomic analysis in different developmental stages of Echinococcus granulosus

Cystic echinococcosis, caused by infection with the larval stage of the cestode Echinococcus granulosus, is a chronic zoonosis. The lifecycle of the E. granulosus parasite includes three consecutive stages that require specific gene regulation or protein expression to survive environmental shifts between definitive hosts and intermediate hosts. The aim of the present study is to screen and analyze the stage differential antigens to be considered for vaccine development against E. granulosus. By using the iTRAQ (isobaric tags for relative and absolute quantification) method, the differentially expressed proteins were selected from the three consecutive developmental stages of E. granulosus: oncosphere, adult tapeworms, and protoscolex. Through a bioinformatics analysis including Clusters of Orthologous Groups (COG), Gene Ontology (GO), and pathway metabolic annotation, we identified some proteins of interest from each stage. The results showed that a large number of differentially expressed proteins (375: oncosphere vs. adult, 346: oncosphere vs. protoscolex, and 391: adult vs. protoscolex) were identified from the three main lifecycle stages. Analysis of the differential protein pathways showed that these differential proteins are mainly enriched in metabolic pathways, Huntington’s diseases, Alzheimer’s diseases, and ribosome metabolic pathways. Interestingly, among these differential proteins, expression levels of paramyosin, HSP60, HSP70, HSP90, cathepsin L1, cathepsin D, casein kinase, and calmodulin were significantly higher in the oncosphere than in the adult or protoscolex (p < 0.05). We hope our findings will help to identify potential targets for diagnosis or for therapeutic and prophylactic intervention.

The acaricidal mechanism and active compounds against Psoroptes cuniculi of the methanol extract of Adonis coerulea Maxim II: Integrated proteomics and SPR analysis

Adonis coerulea Maxim. as a folk medicine, presented acaricidal acitvity. However, the mode of action and active compounds were unclear. In this study, using proteomics and surface plasmon resonance (SPR) technology the mode of action and active compounds of A. coerulea were investigated, as well as a sensitive and environmentally friendly analytical method developed. Proteomics analysis results showed that after treatment of mites with A. coerulea methanol extract (MEAC), 135 proteins were differentially expressed, most of them enriched in the myocardium pathway and participated in the function of the inflated cystic organ. Na+-K+-ATPase may be a potential target. Then, it was used as a target to capture the compounds from the extract using a SPR test. Twelve compounds were found, five compounds, namely ellagic acid, ouabain, convallatoxin, strophanthidin and cymarin presented the higher affinity with Na+-K+-ATPase in molecular docking test. Further study showed that the latter four compounds presented the stronger cytotoxicity and the inhibitory effect on Na+-K+-ATPase with IC50 values ranging with 2.38-0.56 μg/mL, and also showed toxicity against Psoroptes cuniculi. These results indicated that MEAC presented toxicity against mites by inhibiting Na+-K+-ATPase, and cardiac glycosides may be active compounds of this plant in terms of its acaricidal activity. Only 10 g of plant was used to investigate its active compounds. This study lays the foundation for developing sensitive methods for active compound detection.

Differential expression of microRNA between normally developed and underdeveloped female worms of Schistosoma japonicum

Eggs produced by bisexual infected mature female worms (MF) of Schistosoma japonicum are important in the transmission of the parasite and responsible for the pathogenesis of schistosomiasis. The single-sex infected female worms (SF) cannot mature and do not produce normal eggs; also they do not induce severe damage to the host. In this study, the microRNA (miRNA) expression profiles of 25d MF and 25d SF were investigated through Solexa deep-sequencing technology to explore the developmental mechanisms of schistosome female worms. There were 36 differentially expressed miRNA, 20 up-regulated and 16 down-regulated found in MF/SF worms, including some development related miRNA such as bantam (ban), let-7, miR-124, miR-8, miR-1, miR-7. There were 166 target genes of up-regulated miRNA and 201 target genes of down-regulated miRNA after comparing the target gene prediction software results with RNA-Seq transcriptome results. Analysis of the target genes shows that different ones are involved in MF and SF worms in Gene Ontology terms, with a similar situation in KEGG. This observation indicates that different genes regulated by differentially expressed miRNA take part in MF and SF and lead to differential sexual status. This means that the sexual status of female worms is regulated by miRNA.

Comparative Transcriptome Analyses of Schistosoma japonicum Derived From SCID Mice and BALB/c Mice: Clues to the Abnormality in Parasite Growth and Development

Schistosomiasis, caused by the parasitic flatworms called schistosomes, remains one of the most prevailing parasitic diseases in the world. The prodigious oviposition of female worms after maturity is the main driver of pathology due to infection, yet our understanding about the regulation of development and reproduction of schistosomes is limited. Here, we comparatively profiled the transcriptome of Schistosoma japonicum recovered from SCID and BALB/c mice, which were collected 35 days post-infection, when prominent morphological abnormalities could be observed in schistosomes from SCID mice, by performing RNA-seq analysis. Of the 11,183 identified genes, 62 differentially expressed genes (DEGs) with 39 upregulated and 23 downregulated messenger RNAs (mRNAs) were found in male worms from SCID mice (S_M) vs. male worms from BALB/c mice (B_M), and 240 DEGs with 152 upregulated and 88 downregulated mRNAs were found in female worms from SCID mice (S_F) vs. female worms from BALB/c mice (B_F). We also tested nine DEGs with a relatively higher expression abundance in the gonads of the worms (ovary, vitellaria, or testis), suggesting their potential biological significance in the development and reproduction of the parasites. Gene ontology (GO) enrichment analysis revealed that GO terms such as “microtubule-based process,” “multicellular organismal development,” and “Rho protein signal transduction” were significantly enriched in the DEGs in S_F vs. B_F, whereas GO terms such as “oxidation–reduction process,” “response to stress,” and “response to DNA damage stimulus” were significantly enriched in the DEGs in S_M vs. B_M. These results revealed that the differential expression of some important genes might contribute to the morphological abnormalities of worms in SCID mice. Furthermore, we selected one DEG, the mitochondrial prohibitin complex protein 1 (Phb1), to perform double-stranded RNA (dsRNA)-mediated RNA interference (RNAi) in vivo targeting the worms in BALB/c mice, and we found that it was essential for the growth and reproductive development of both male and female S. japonicum worms. Taken together, these results provided a wealth of information on the differential gene expression profiles of schistosomes from SCID mice when compared with those from BALB/c mice, which were potentially involved in regulating the growth and development of schistosomes. These findings contributed to an understanding of parasite biology and provided a rich resource for the exploitation of antischistosomal intervention targets.