SUMMARY: 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.

Echinococcosis is a parasitic disease caused by the metacestodes of Echinococcus spp. The disease has a long latent period and is largely underdiagnosed, partially because of the lack of effective early diagnostic approaches. Using liquid chromatography-mass spectrometry, we profiled the serum-derived extracellular vesicles (EVs) of E. multilocularis-infected mice and identified three parasite-origin proteins, thioredoxin peroxidase 1 (TPx-1), transitional endoplasmic reticulum ATPase (TER ATPase), and 14-3-3, being continuously released by the parasites into the sera during the infection via EVs. Using ELISA, both TPx-1 and TER ATPase were shown to have a good performance in diagnosis of experimental murine echinococcosis as early as 10 days post infection and of human echinococcosis compared with that of control. Moreover, TER ATPase and TPx-1 were further demonstrated to be suitable for evaluation of the prognosis of patients with treatment. The present study discovers the potential of TER ATPase and TPx-1 as promising diagnostic candidates for echinococcosis.

Liver fibrosis is one of the histopathological characters duringEchinococcus multilocularisinfection. The activation of hepatic stellate cells (HSCs) is a key event in the development of liver fibrosis. However, the molecular mechanism of HSC activation in theE.multilocularisinfection-induced liver fibrosis remains largely unclear. Here, we reported that mmu-miR-342-3p was most dominantly expressed in HSCs and was upregulated in the HSCs in response toE.multilocularisinfection. We further showed that mmu-miR-342-3p was able to bind to the 3’ UTR of theZbtb7agene and regulated its expression. Moreover, mmu-miR-342-3p expression was negatively correlated with its target geneZbtb7ain HSCs duringE.multilocularisinfection. Knockdown of mmu-miR-342-3p promoted the expression ofGfapin the activated HSCsin vitro. In theE.multilocularis-infected mice, knockdown of mmu-miR-342-3p suppressed the expression ofα-Sma,Col1α1, andTGF-βbut promoted the expression ofGfap. Therefore, mmu-miR-342-3p is a key regulator for activation of HSCs, and inhibiting mmu-miR-342-3p to suppressed Zbtb7a-mediated TGF-β signaling in activated HSCs could be a novel strategy to treat liver fibrosis induced byE.multilocularis.

Background: Cystic echinococcosis (CE) is a serious parasitic zoonosis caused by the larvae of the tapeworm Echinococcus granulosus. The development of an effective vaccine is one of the most promising strategies for controlling CE. Methods: The E. granulosus 3-hydroxyacyl-CoA dehydrogenase (EgHCDH) gene was cloned and expressed in Escherichia coli. The distribution of EgHCDH in protoscoleces (PSCs) and adult worms was analyzed using immunofluorescence. The transcript levels of EgHCDH in PSCs and adult worms were analyzed using quantitative real-time reverse transcription PCR (RT-qPCR). The immune protective effects of the rEgHCDH were evaluated. Results: The 924-bp open reading frame sequence of EgHCDH, which encodes a protein of approximately 34 kDa, was obtained. RT-qPCR analysis revealed that EgHCDH was expressed in both the PSCs and adult worms of E. granulosus. Immunofluorescence analysis showed that EgHCDH was mainly localized in the tegument of PSCs and adult worms. Western blot analysis showed that the recombinant protein was recognized by E. granulosus-infected dog sera. Animal challenge experiments demonstrated that dogs immunized with recombinant (r)EgHCDH had significantly higher serum IgG, interferon gamma and interleukin-4 concentrations than the phosphate-buffered saline (PBS) control group. The rEgHCDH vaccine was able to significantly reduce the number of E. granulosus and inhibit the segmental development of E. granulosus compared to the PBS control group. Conclusions: The results suggest that rEgHCDH can induce partial immune protection against infection with E. granulosus and could be an effective candidate for the development of new vaccines. Graphical

Alveolar echinococcosis (AE) is a zoonotic helminthic disease caused by infection with the larval of Echinococcus multilocularis in human and animals. Here, we compared miRNA profiles of the peritoneal macrophages of E. multilocularis-infected and un-infected female BALB/c mice using high-throughput sequencing. A total of 87 known miRNAs were differentially expressed (fold change ≥ 2, p < 0.05) in peritoneal macrophages in mice 30- and 90-day post infection compared with ones in un-infected mice. An increase of mmu-miR-155-5p expression was observed in peritoneal macrophages in E. multilocularis-infected mice. Compared with the control group, the production of nitric oxide (NO) was increased in peritoneal macrophages transfected with mmu-miR-155-5p mimics at 12 h after transfection (p < 0.001). Two key genes (CD14 and NF-κB) in the LPS/TLR4 signaling pathway were also markedly altered in mmu-miR-155-5p mimics transfected cells (p < 0.05). Moreover, mmu-miR-155-5p mimics suppressed IL6 mRNA expression and promoted IL12a and IL12b mRNA expression. Luciferase assays showed that mmu-miR-155-5p was able to bind to the 3′ UTR of the IKBKE gene and decreased luciferase activity. Finally, we found the expression of IKBKE was significantly downregulated in both macrophages transfected with mmu-miR-155-5p and macrophages isolated from E. multilocularis-infected mice. These results demonstrate an immunoregulatory effect of mmu-miR-155 on macrophages, suggesting a role in regulation of host immune responses against E. multilocularis infection.