Parasite-derived microRNAs in plasma as novel promising biomarkers for the early detection of hydatid cyst infection and post-surgery follow-up.

Cystic echinococcosis is a worldwide chronic zoonotic disease that threatens human health and animal husbandry. Exosome-like vesicles (ELVs) have emerged recently as mediators in the parasite-parasite intercommunication and parasite-host interactions. Exosome-like vesicles from parasites can transfer non-coding RNAs (ncRNAs) into host cells to regulate their gene expression; however, the ncRNAs profiles of the ELVs from Echinococcus granulosus remain unknown. Here, we isolated protoscolece (PSC)-ELVs and hydatid fluid (HF)-ELVs from the culture medium for E. granulosus PSCs in vitro and the HF of fertile sheep cysts, respectively. The microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) profiles of the two types of ELVs were analyzed using high-throughput sequencing, and their functions were predicted using Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis. In PSC-ELVs and HF-ELVs, 118 and 58 miRNAs were identified, respectively, among which 53 miRNAs were present in both ELVs, whereas 65 and 5 miRNAs were unique to PSC-ELVs and HF-ELVs, respectively; 2,361 and 1,254 lncRNAs were identified in PSC-ELVs and HF-ELVs, respectively, among which 1,004 lncRNAs were present in both ELVs, whereas 1,357 and 250 lncRNAs were unique to PSC-ELVs and HF-ELVs, respectively. Intriguingly, the spilled PSCs from cysts excrete ELVs with higher numbers of and higher expression levels of miRNAs and circRNAs than HF-ELVs. The miRNA sequencing data were validated by quantitative reverse transcription-polymerase chain reaction. Furthermore, the target lncRNAs and mRNAs regulated by the 20 most abundant miRNAs were screened, and a ceRNA regulatory network containing 5 miRNAs, 41 lncRNAs, and 23 mRNAs was constructed, which provided new ideas and the molecular basis for further clarification of the function and mechanism of E. granulosus ELVs ncRNAs in the parasite-host interactions. Egr-miR-125-5p and egr-miR-10a-5p, sharing identical seed sites with host miRNAs, were predicted to mediate inflammatory response, collagen catabolic process, and mitogen-activated protein kinase cascade during parasite infections. In conclusion, for the first time, we identified the ncRNAs profiles in PSC-ELVs and HF-ELVs that might be involved in host immunity and pathogenesis, and enriched the ncRNAs data of E. granulosus. These results provided valuable resources for further analysis of the regulatory potential of ncRNAs, especially miRNAs, in both types of ELVs at the parasite-host interface.

/pdf/comprehensive-analysis-of-non-coding-rna-profiles-of-exosome-uwd25jkua2.pdf

Comprehensive Analysis of Non-coding RNA Profiles of Exosome-Like Vesicles From the Protoscoleces and Hydatid Cyst Fluid of Echinococcus granulosus.

Novel tools for early diagnosis and monitoring of schistosomiasis are urgently needed. This study aimed to validate parasite-derived miRNAs as potential novel biomarkers for the detection of human Schistosoma japonicum infection. A total of 21 miRNAs were initially validated by real-time-polymerase chain reaction (RT-PCR) using serum samples of S. japonicum-infected BALB/c mice. Of these, 6 miRNAs were further validated with a human cohort of individuals from a schistosomiasis-endemic area of the Philippines. RT-PCR analysis showed that two parasite-derived miRNAs (sja-miR-2b-5p and sja-miR-2c-5p) could detect infected individuals with low infection intensity with moderate sensitivity/specificity values of 66%/68% and 55%/80%, respectively. Analysis of the combined data for the two parasite miRNAs revealed a specificity of 77.4% and a sensitivity of 60.0% with an area under the curve (AUC) value of 0.6906 (P = 0.0069); however, a duplex RT-PCR targeting both sja-miR-2b-5p and sja-miR-2c-5p did not result in an increased diagnostic performance compared with the singleplex assays. Furthermore, the serum level of sja-miR-2c-5p correlated significantly with faecal egg counts, whereas the other five miRNAs did not. Targeting S. japonicum-derived miRNAs in serum resulted in a moderate diagnostic performance when applied to a low schistosome infection intensity setting.

/pdf/parasite-derived-circulating-micrornas-as-biomarkers-for-the-3ihowse690.pdf

Parasite-derived circulating microRNAs as biomarkers for the detection of human Schistosoma japonicum infection.

As an adaption to their complex lifecycles, helminth parasites garner a unique repertoire of genes at different developmental stages with subtle regulatory mechanisms. These parasitic worms release differential components such as microRNAs (miRNAs) and extracellular vesicles (EVs) as mediators which participate in the host-parasite interaction, immune regulation/evasion, and in governing processes associated with host infection. MiRNAs are small (~ 22-nucleotides) non-coding RNAs that regulate gene expression at the post-transcriptional level, and can exist in stable form in bodily fluids such as serum/plasma, urine, saliva and bile. In addition to reports focusing on the identification of miRNAs or in the probing of differentially expressed miRNA profiles in different development stages/sexes or in specific tissues, a number of studies have focused on the detection of helminth-derived miRNAs in the mammalian host circulatory system as diagnostic biomarkers. Extracellular vesicles (EVs), small membrane-surrounded structures secreted by a wide variety of cell types, contain rich cargos that are important in cell-cell communication. EVs have attracted wide attention due to their unique functional relevance in host-parasite interactions and for their potential value in translational applications such as biomarker discovery. In the current review, we discuss the status and potential of helminth parasite-derived circulating miRNAs and EV cargos as novel diagnostic tools.

/pdf/parasitic-helminth-derived-micrornas-and-extracellular-2lcsbv639q.pdf

Parasitic Helminth-Derived microRNAs and Extracellular Vesicle Cargos as Biomarkers for Helminthic Infections.

MicroRNAs (miRNAs) are a kind of small non-coding RNA molecules that could regulate multiple biological pathways at posttranscriptional level. Over 2,000 miRNAs have so far been discovered in humans, and many of them are found to be linked to various kinds of diseases. Thus, miRNAs are being considered as clinical diagnostic and therapeutic targets. With the discovery of high stability of circulating miRNAs in various kinds of mammalian body fluids, the potential of circulating miRNAs as diagnostic/prognostic biomarkers of infectious diseases aroused great interest among researchers. As far as human diseases are concerned, some biomarkers based on circulating miRNAs have been progressed to clinical application. In veterinary fields, however, this concept is only beginning to come into view. In this review, we summarize an update of preclinical studies on using circulating miRNAs as diagnostic biomarkers to combat infectious diseases that affect domestic animals.

/pdf/circulating-micrornas-as-potential-biomarkers-for-veterinary-s4btb4subm.pdf

Circulating MicroRNAs As Potential Biomarkers for Veterinary Infectious Diseases.

Echinococcus multilocularis is a most pathogenic zoonotic tapeworm that causes devastating echinococcosis in both humans and animals. Circulating microRNAs (miRNAs) are stably existed in the serum/plasma of mammalian hosts during helminthic infection. In this study, we compared the host-circulating miRNA expression in the sera from the E. multilocularis-infected and uninfected mice. A total of 58 host-origin serum miRNAs were differentially expressed (2 ⩾ fold change, P < 0·05), of which 21 were upregulated and 37 were significantly downregulated. Consistent with the sequencing data, quantitative polymerase chain reaction (PCR) results showed that the expression levels of four miRNAs were elevated gradually and one decreased gradually at the E. multilocularis infection time points. Moreover, seven of E. multilocularis specific miRNAs were identified in the sera. Real-time PCR analyses further demonstrated that only two parasite-derived miRNAs (emu-miR-10 and emu-miR-227) were specifically amplified in all the sera from mice infected with E. multilocularis. These findings will be helpful to understand the roles of miRNAs in host-parasite interaction and to potentiate serum miRNAs as diagnostic targets for echinococcosis.

Expression profiling of circulating miRNAs in mouse serum in response to Echinococcus multilocularis infection.

MicroRNAs (miRNAs) are short noncoding RNAs, involved in the regulation of parasite diseases. However, a role of miRNAs in Echinococcus multilocularis infection remains largely unknown. In this study, we first found the expression levels of key genes involved in miRNA biogenesis and function, including Ago2, Xpo5, Tarbp2 and DgcR8, were obviously altered in the macrophage RAW264·7 cells exposed to E. multilocularis metacestodes. Compared with the control, 18 and 32 known miRNAs were found to be differentially expressed (P 2) in the macrophages exposed to E. multilocularis metacestodes for 6 and 12 h, respectively. Among these, several are known to be involved in regulating cytokine activities and immune responses. Quantitative real-time polymerase chain reaction results showed that the expression of nine selected miRNAs was consistent with the sequencing data at each treatment time points. Moreover, there were statistically significant correlations between the expression levels of miRNAs and their corresponding targeted genes. Our data give us some clues to pinpoint a role of miRNAs in the course of infection and immunity of E. multilocularis.

Yadong Zheng

Papers

Expression profiling of circulating miRNAs in mouse serum in response to Echinococcus multilocularis infection.

MicroRNA expression profile in RAW264·7 macrophage cells exposed to Echinococcus multilocularis metacestodes