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

MiR-374b-5p Regulates T Cell Differentiation and Is Associated with rEg.P29 Immunity

Cystic echinococcosis (CE) is a zoonotic disease caused by Echinococcus granulosus (Eg) infection. Our previous study confirmed that recombinant Eg.P29 (rEg.P29) could protect against echinococcus granulosus secondary infection in sheep and mice. The aim of the study was to investigate the association between immunoprotection of rEg.P29 vaccine and mmu-miR-374b-5p (miR-374b-5p) and study the immunity influence of miR-374b-5p on CD4⁺ T cells in mice spleen. MiR-374b-5p level was significantly increased after the second-week and the fourth week of vaccination with rEg.P29. Overexpression of miR-374b-5p increased IFN-γ, IL-2, IL-17A mRNA levels and decreased IL-10 mRNA levels in CD4⁺ T cells. Moreover, the inhibition of miR-374b-5p decreased IFN-γ and IL-17A and increased IL-10 mRNA levels in CD4⁺ T cells; this was further confirmed by the flow cytometry. The vaccination of rEg.P29 enhanced miR-374b-5p expression that was associated with a higher Th1 and Th17 immune response, a lower IL-10 mRNA production with miR-374b-5p overexpression, a lower Th1 immune response, and a higher IL-10 mRNA levels with miR-374b-5p inhibitions. To sum up, these data suggest that miR-374b-5p may participate in rEg.P29 immunity by regulating Th1 and Th17 differentiation.

Profiling of miRNAs in Mouse Peritoneal Macrophages Responding to Echinococcus multilocularis Infection

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.

miRNAs and lncRNAs in Echinococcus and Echinococcosis

Echinococcosis are considered to be potentially lethal zoonotic diseases that cause serious damage to hosts. The metacestode of Echinococcus multilocularis and E. granulosus can result in causing the alveolar and cystic echinococcoses, respectively. Recent studies have shown that non-coding RNAs are widely expressed in Echinococcus spp. and hosts. In this review, the two main types of non-coding RNAs—long non-coding RNAs (lncRNAs) and microRNAs (miRNAs)—and the wide-scale involvement of these molecules in these parasites and their hosts were discussed. The expression pattern of miRNAs in Echinococcus spp. is species- and developmental stage-specific. Furthermore, common miRNAs were detected in three Echinococcus spp. and their intermediate hosts. Here, we primarily focus on recent insights from transcriptome studies, the expression patterns of miRNAs and lncRNAs, and miRNA-related databases and techniques that are used to investigate miRNAs in Echinococcus and echinococcosis. This review provides new avenues for screening therapeutic and diagnostic markers.

The effect of albendazole sulfoxide on the expression of miR-61 and let-7 in different in vitro developmental stages of Echinococcus granulosus

Albendazole, as the main anti-echinococcal benzimidazole, has demonstrated safe and effective therapeutic outcomes in the treatment of echinococcosis. The emergence of resistance or reduced response to albendazole sulfoxide (ABZ_SOX) and other benzimidazoles have been demonstrated in several parasitic helminths of medical and veterinary importance. As the genetic makeup and miRNA profile of helminths affects their response to albendazole sulfoxide, the present study was conducted to investigate the expression of miRNAs in different developmental stages of Echinococcus granulosus exposed to albendazole sulfoxide in vitro. Different developmental stages of the helminth were obtained from in vitro cultured E. granulosus in monophasic and diphasic media. In both ABZ-SOX-treated and control parasites miRNAs were extracted from microcysts, intact protoscoleces and strobilated worms with one and three segments. Expression of two miRNAs, let-7 and miR-61 was evaluated using RT-qPCR for each stage. Results of the present study revealed significant differential expression of both let-7 and miR-61 at different drug concentrations. A significant difference of let-7 expression was observed between the strobilated and metacestode stages of E. granulosus exposed to ABZ-SOX. In the treated protoscoleces, let-7 expression was significantly reduced in the presence of ABZ-SOX at 1000 μg/ml concentration. In contrast higher expression levels were documented in the segmented worms. In the microcysts exposed to different drug concentrations a significant decline of miR-61 expression was demonstrated. Also, a significant increase in expression of miR-61 was observed in one proglottid worms as well as the protoscoleces. Under high drug concentration or long-term exposure of the protoscoleces to ABZ-SOX significantly higher miR-61 expression was observed compared to the controls. Our findings suggested that under in vitro benzimidazole exposure the expression of two E. granulosus miRNAs were significantly affected in the microcyst stage. This study presents the first evidence of the nature of benzimidazole effects on miRNA expression in platyhelminths.

Taenia crassiceps-Excreted/Secreted Products Induce a Defined MicroRNA Profile that Modulates Inflammatory Properties of Macrophages

Helminth parasites modulate immune responses in their host to prevent their elimination and to establish chronic infections. Our previous studies indicate that Taenia crassiceps-excreted/secreted antigens (TcES) downregulate inflammatory responses in rodent models of autoimmune diseases, by promoting the generation of alternatively activated-like macrophages (M2) in vivo. However, the molecular mechanisms triggered by TcES that modulate macrophage polarization and inflammatory response remain unclear. Here, we found that, while TcES reduced the production of inflammatory cytokines (IL-6, IL-12, and TNFα), they increased the release of IL-10 in LPS-induced bone marrow-derived macrophages (BMDM). However, TcES alone or in combination with LPS or IL-4 failed to increase the production of the canonical M1 or M2 markers in BMDM. To further define the anti-inflammatory effect of TcES in the response of LPS-stimulated macrophages, we performed transcriptomic array analyses of mRNA and microRNA to evaluate their levels. Although the addition of TcES to LPS-stimulated BMDM induced modest changes in the inflammatory mRNA profile, it induced the production of mRNAs associated with the activation of different receptors, phagocytosis, and M2-like phenotype. Moreover, we found that TcES induced upregulation of specific microRNAs, including miR-125a-5p, miR-762, and miR-484, which are predicted to target canonical inflammatory molecules and pathways in LPS-induced BMDM. These results suggest that TcES can modulate proinflammatory responses in macrophages by inducing regulatory posttranscriptional mechanisms and hence reduce detrimental outcomes in hosts running with inflammatory diseases.

Suppression of mouse miRNA-222-3p in response to Echinococcus multilocularis infection

During Echinococcus multilocularis infection, serum miR-222-3p is dramatically downregulated, but its role is yet to be established. Here the expression of miR-222-3p in the spleen of infected mice was shown to be significantly decreased in response to parasite infection (p < 0.05). Using RAW264.7 macrophages, it was further demonstrated that E. multilocularis crude antigens significantly inhibited miR-222-3p expression (p < 0.01). In macrophages transfected with a miR-222-3p inhibitor, NO secretion was moderately decreased compared with the control (p < 0.05). Although all the pro- and anti-inflammatory cytokine genes tested kept constant in expression, four key genes involved in the LPS/TLR4 signaling pathway were significantly down- or up-regulated in transfected cells (p < 0.05), including CD14, TLR4, TICAM2 and AP-1. These results suggest that downregulated miR-222-3p is capable of modulating macrophage immune functions, possibly contributing to the pathogenesis during E. multilocularis infection.