Toxocara canis is a neglected zoonotic parasite, which threatens the health of dogs and humans worldwide. The molecular mechanisms that underlie the progression of T. canis infection remain mostly unknown. MicroRNAs (miRNAs) are small non-coding RNAs that have been identified in T. canis; however, the regulation and role of miRNAs in the host during infection remain incompletely understood. In this study, we determined hepatic miRNA expression at different stages of T. canis infection in beagle dogs. Individual dogs were infected by 300 embryonated T. canis eggs, and their livers were collected at 12 hpi (hours post-infection), 24 hpi, and 36 dpi (days post-infection). The expression profiles of liver miRNAs were determined using RNA-sequencing. Compared to the control groups, 9, 16, and 34 differentially expressed miRNAs (DEmiRNAs) were detected in the livers of infected dogs at the three infection stages, respectively. Among those DEmiRNAs, the novel-294 and cfa-miR-885 were predicted to regulate inflammation-related genes at the initial stage of infection (12 hpi). The cfa-miR-1839 was predicted to regulate the target gene TRIM71, which may influence the development of T. canis larvae at 24 hpi. Moreover, cfa-miR-370 and cfa-miR-133c were associated with immune response at the final stage of infection (36 dpi). Some immunity-related Gene Ontology terms were enriched particularly at 24 hpi. Likewise, Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that many significantly enriched pathways were involved in inflammation and immune responses. The expression level of nine DEmiRNAs was validated using quantitative real-time PCR (qRT-PCR). These results show that miRNAs play critical roles in the pathogenesis of T. canis during the hepatic phase of parasite development. Our data provide fundamental information for further investigation of the roles of miRNAs in the innate/adaptive immune response of dogs infected by T. canis.

犬弓形虫是一种被忽视的人畜共患寄生虫，威胁着世界范围内狗和人类的健康。导致癌症进展的分子机制T.犬感染仍然未知。MicroRNA（miRNA）是小型非编码RNA，已在T.犬; 然而，miRNA在宿主中的调控和作用在感染期间仍未完全了解。在这项研究中，我们确定了肝miRNA在不同阶段的表达T.犬比格犬感染。个别狗感染了300只胚胎T.犬在感染后12小时（感染后数小时），感染24天和36 dpi（感染后数天）收集卵和肝脏。使用RNA测序确定肝脏miRNA的表达谱。与对照组相比，在三个感染阶段分别在感染犬的肝脏中检测到9、16和34个差异表达的miRNA（DEmiRNA）。在这些DEmiRNA中，预计Novel-294和cfa-miR-885在感染的初始阶段（12 hpi）会调节炎症相关基因。预计cfa-miR-1839会调控靶基因TRIM71，这可能会影响cfa-miR-1839的发育。T.犬幼虫在24 hpi。而且，cfa-miR-370和cfa-miR-133c在感染的最后阶段（36 dpi）与免疫反应有关。一些与免疫有关的基因本体论术语尤其在24 hpi时得到了丰富。同样，《京都基因与基因组百科全书》途径分析表明，许多明显丰富的途径与炎症和免疫反应有关。使用定量实时PCR（qRT-PCR）验证了九种DEmiRNA的表达水平。这些结果表明，miRNA在肝癌的发病过程中起关键作用。T.犬在寄生虫发育的肝阶段。我们的数据为进一步研究miRNA在受感染狗的先天/适应性免疫反应中的作用提供了基础信息。T.犬。