Differential expression of microRNAs in the non-permissive schistosome host Microtus fortis under schistosome infection

Comprehensive analysis of miRNA profiling in Schistosoma mekongi across life cycle stages

Schistosoma mekongi, a significant schistosome parasite, has various life stages, including egg, cercaria, female, and male, that play crucial roles in the complex life cycle. This study aimed to explore the microRNA (miRNA) profiles across these developmental stages to understand their potential functions and evolutionary significance, which have not been studied. Pre-processed sequencing reads of small RNA (sRNA) were obtained, and annotations were performed against the S. japonicum reference miRNA database. Results indicated marked variations in miRNA profiles across different life stages, with notable similarities observed between female and male S. mekongi. Principal Coordinate Analysis (PCoA) and unsupervised clustering revealed distinct miRNA signatures for each stage. Gene ontology (GO) analysis unveiled the potential roles of these miRNAs in various biological processes. The differential expression of specific miRNAs was prominent across stages, suggesting their involvement in crucial developmental processes. Furthermore, orthologous miRNA analysis against various worm species revealed distinct presence-absence patterns, providing insights into the evolutionary relationships of these miRNAs. In conclusion, this comprehensive investigation into the miRNA profiles of S. mekongi offers valuable insights into the functional and evolutionary aspects of miRNAs in schistosome biology.

Macrophage-mediated trogocytosis contributes to destroying human schistosomes in a non-susceptible rodent host, Microtus fortis

Schistosoma parasites, causing schistosomiasis, exhibit typical host specificity in host preference. Many mammals, including humans, are susceptible to infection, while the widely distributed rodent, Microtus fortis, exhibits natural anti-schistosome characteristics. The mechanisms of host susceptibility remain poorly understood. Comparison of schistosome infection in M. fortis with the infection in laboratory mice (highly sensitive to infection) offers a good model system to investigate these mechanisms and to gain an insight into host specificity. In this study, we showed that large numbers of leukocytes attach to the surface of human schistosomes in M. fortis but not in mice. Single-cell RNA-sequencing analyses revealed that macrophages might be involved in the cell adhesion, and we further demonstrated that M. fortis macrophages could be mediated to attach and kill schistosomula with dependence on Complement component 3 (C3) and Complement receptor 3 (CR3). Importantly, we provided direct evidence that M. fortis macrophages could destroy schistosomula by trogocytosis, a previously undescribed mode for killing helminths. This process was regulated by Ca2+/NFAT signaling. These findings not only elucidate a novel anti-schistosome mechanism in M. fortis but also provide a better understanding of host parasite interactions, host specificity and the potential generation of novel strategies for schistosomiasis control.

Comparative characterization of microRNAs of Schistosoma japonicum from SCID mice and BALB/c mice: Clues to the regulation of parasite growth and development

Schistosomiasis, caused by a parasite with a wide range of mammalian hosts, remains one of the most prevailing parasitic diseases in the world. While numerous studies have reported that the growth and reproduction of schistosomes in immunodeficient mice was significantly retarded, the underlying molecular mechanisms have yet to be revealed. In this study, we comparatively analyzed the microRNA expression of Schistosoma japonicum derived from SCID and BALB/c mice on the 35^th day post-infection by high-throughput RNA sequencing as prominent morphological abnormalities had been observed in schistosomes from SCID mice when compared with those from BALB/c mice. The results revealed that more than 72% and 61% of clean reads in the small RNA libraries of female and male schistosomes, respectively, could be mapped to the selected miRs in the miRBase or the sequences of species-specific genomes. Further analysis identified 122 miRNAs using TPM >0.01 as the threshold value, including 75 known and 47 novel miRNAs, 96 of which were commonly expressed across all the four tested schistosome libraries. Comparative analysis of the libraries of schistosomes from SCID and BALB/c mice identified 15 differentially expressed miRNAs (5 up-regulated and 10 down-regulated) among females and 16 among males (9 up-regulated and 7 down-regulated). Integrated analysis of the two sets of differentially expressed miRNAs of female and male worms identified 2 miRNAs (sja-miR-3488 and sja-miR-novel_29) that overlapped between female and male datasets. Prediction of miRNA targets and Gene Ontology (GO) term enrichment analysis of the predicted target genes revealed that these genes were involved in some important biological processes, such as nucleic acid metabolic process, macromolecule modification, and cellular aromatic compound metabolic process. The predicted target genes were further matched to the differentially expressed genes in male and female schistosomes from the above two hosts, obtaining 7 genes that may be responsible for regulating the growth, development and sex maturation of schistosomes. Taken together, this study provides the first identification of differentially expressed miRNAs in schistosomes from SCID and BALB/c mice. These miRNAs and their predicted target mRNAs are probably involved in the regulation of development, growth, and maturation of schistosomes. Therefore, this study expands our understanding of schistosome development regulation and host-parasite relationship, and also provides a valuable set of potential anti-schistosomal targets for prevention and control of schistosomiasis.

Transcriptional profiling of Microtus fortis responses to S. japonicum: New sight into Mf-Hsp90α resistance mechanism

AIMS

Schistosomiasis is a parasitic disease with a chronic debilitating character caused by parasitic flatworms of the genus Schistosoma. The main disease-causing species of Schistosoma in China is S. japonicum. M fortis has been proved to be a nonpermissive host of S. japonicum. Mf-HSP90α (Microtus fortis heat shock protein 90alpha), the homologue of HSP90α, display anti-schistosome effect in vitro and in vivo. In the current study, in order to investigate the mechanism of anti-schistosome effect of Mf-HSP90α, we conducted RNA-Seq to obtain the transcriptome profile of M. fortis liver infected with S. japonicum at different time points.

METHODS AND RESULTS

By mapping the differential expressed genes (DEGs) to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), we found that the JAK2/STAT1 pathway was highly enriched with an elevated level of IL-10 and HSP90α. We then checked the IL-10-JAK2/STAT1-HSP90α pathway, and found that this pathway was activated in the infected mice with S. japonicum. The expression of the molecules in this pathway was elevated on the 10^th day after infection and gradually decreased on the 20^th day.

CONCLUSIONS

The IL-10-JAK2/STAT1-HSP90α axis was associated with the anti-schistosome effect of Mf-HSP90α, and targeting IL-10-JAK2/STAT1-HSP90α axis might be a novel therapeutic strategy for developing resistance to S. japonicum infection.

Genome assembly and transcriptome analysis provide insights into the antischistosome mechanism of Microtus fortis

Microtus fortis is the only mammalian host that exhibits intrinsic resistance against Schistosoma japonicum infection. However, the underlying molecular mechanisms of this resistance are not yet known. Here, we perform the first de novo genome assembly of M. fortis, comprehensive gene annotation analysis, and evolution analysis. Furthermore, we compare the recovery rate of schistosomes, pathological changes, and liver transcriptomes between M. fortis and mice at different time points after infection. We observe that the time and type of immune response in M. fortis are different from those in mice. M. fortis activates immune and inflammatory responses on the 10th day post infection, such as leukocyte extravasation, antibody activation, Fc-gamma receptor-mediated phagocytosis, and the interferon signaling cascade, which play important roles in preventing the development of schistosomes. In contrast, an intense immune response occurrs in mice at the late stages of infection and could not eliminate schistosomes. Infected mice suffer severe pathological injury and continuous decreases in cell cycle, lipid metabolism, and other functions. Our findings offer new insights into the intrinsic resistance mechanism of M. fortis against schistosome infection. The genome sequence also provides the basis for future studies of other important traits in M. fortis.

Mechanisms of Resistance to Schistosoma japonicum Infection in Microtus fortis, the Natural Non-permissive Host

Human schistosomiasis, which is caused by schistosomes, is a zoonosis that is difficult to control because of the many reservoir hosts. However, Microtus fortis is the only mammal that is naturally resistant to Schistosoma japonicum infection known in China, in which S. japonicum growth and development were arrested on day 12, and the worms eliminated on day 20 post-infection. In this review, we present an overview of the established and purported mechanisms of resistance to S. japonicum infection in M. fortis in comparison to Rattus norvegicus, a semi-permissive host. Clarifying the mechanism of this efficient resistance can help us to better understand host-parasite interaction and to provide better methods to control schistosomiasis.

A comparison of next-generation sequencing analysis methods for cancer xenograft samples

The application of next-generation sequencing (NGS) technology in cancer is influenced by the quality and purity of tissue samples. This issue is especially critical for patient-derived xenograft (PDX) models, which have proven to be by far the best preclinical tool for investigating human tumor biology, because the sensitivity and specificity of NGS analysis in xenograft samples would be compromised by the contamination of mouse DNA and RNA. This definitely affects downstream analyses by causing inaccurate mutation calling and gene expression estimates. The reliability of NGS data analysis for cancer xenograft samples is therefore highly dependent on whether the sequencing reads derived from the xenograft could be distinguished from those originated from the host. That is, each sequence read needs to be accurately assigned to its original species. Here, we review currently available methodologies in this field, including Xenome, Disambiguate, bamcmp and pdxBlacklist, and provide guidelines for users.

Changes in microRNA expression in response to Schistosoma japonicum infection

Schistosomiasis japonicum is one of the most serious zoonotic diseases in the world. There is increasing evidence to show that host miRNAs are modulated following Schistosoma japonicum infection, and some of these miRNAs may play important regulatory roles in response to schistosome infection. Several host miRNAs have been identified and shown to be potential diagnostic biomarkers or novel therapeutic targets for schistosomiasis. These studies have paved the way to a better understanding of the mechanisms of schistosome-host interaction and may facilitate the development of novel approaches to the control of the disease.

Comparative analysis of microRNA in schistosomula isolated from non-permissive host and susceptible host

The reed vole Microtus fortis is the only known mammal in which the schistosome is naturally prevented from maturing and schistosome infection does not cause significant pathogenesis. However, the mechanism behind this phenomenon remains unknown. In the present study, Solexa deep sequencing technology was used to carry out high-throughput sequencing and comparative analysis of microRNA (miRNA) between small RNA libraries isolated from 10 days oldschistosomula of M. fortis and BALB/c mice.In total, 10d schistosomula from M. fortis and BALB/c mice yielded 13.37 and 10.84 million reads, respectively, and nearly 39% and 40% of reads could be mapped to selected miRNAs in miRbase. Based on a bioinformatic analysis, we found that most of the miRNAs identified in Schistosoma japonicum were detected in our study. Further analysis revealed that 24 miRNAs were differentially expressed between the schistosomula from the two rodents, of which 21 were down-regulated and three were up-regulated in schistosomula from M. fortis. Also, six novel miRNAs were predicted and identified in this study. Target genes were mapped and filtered by correlating them with differentially expressed genes obtained from S. japonicum oligonucleotide microarray analyses performed in previous studies. miRNAs such as miR-10-3p, miR-10-5p, and miR-2b-5p may affect the growth, differentiation, and metabolism of worms via regulation of the expression of target genes such as enolase, aquaporin, TGF-beta-inducible nuclear protein, and paramyosin. Gene Ontology analysis of the predicted target genes of these six differentially expressed miRNAs revealed that some important biological pathways, such as metabolic processes,glycolysis, and catalytic activity, were involved. The results of this study highlight the function of miRNAs in the development and survival of the schistosome, and provide valuable information to increase our understanding of the regulatory function of miRNAs in schistosome development and host-parasite interactions in a differentially susceptible host environment.

Molecular characterization of SjBIRP, another apoptosis inhibitor, from Schistosoma japonicum

Inhibitor of apoptosis proteins (IAP) play an important role in the regulation of apoptotic processes and are defined by the presence of baculoviral IAP repeat (BIR) domains. Here, we characterized a cDNA fragment (SjBIRP) synthesized from the RNA of Schistosoma japonicum, which was found to contain the BIR domain, suggesting that it could encode a potential IAP. Real-time PCR analyses indicated that SjBIRP transcription was detected at several stages of the schistosome's lifecycle, with increased levels present in schistosomula (7 days). In addition, the SjBIRP was highly expressed in adult females as compared to adult males. A functional assay showed that SjBIRP could inhibit caspase3/7 activity in both HeLa cells and schistosome lysates. Furthermore, SjBIRP expression profiles varied between different hosts of S. japonicum. Taken together, our preliminary studies suggest that SjBIRP may play a functional role in the regulation of apoptosis in schistosomes, and that it could be a potential drug target for schistosomiasis control.