Altered miRNA Expression Profiles in the Serum of Beagle Dogs Experimentally Infected with Toxocara canis

SIMPLE SUMMARY: Toxocariasis is a parasitic zoonosis distributed all over the world, but is excessively neglected. Therefore, research on toxocariasis is urgently needed. MicroRNAs (miRNAs) are demonstrated to be useful biomarkers and have multiple biological functions in numerous diseases. However, research on the altered miRNA expression profiles in Beagle dogs infected with Toxocara canis is still inadequate, especially in the serum. Using RNA sequencing technology, the miRNA expression in the serum of Beagle dogs infected with T. canis was examined at 24 h, 10 days and 36 days, and several differently expressed miRNAs were identified. This study indicated that T. canis infection can alter the expression of miRNAs in the serum of Beagle dogs and provided baseline data to further clarify the regulatory signaling networks involved in the pathogenesis of toxocariasis. ABSTRACT: Toxocara canis is a neglected roundworm, which can cause debilitating disease in dogs and humans worldwide. Serum is an excellent material for monitoring the occurrence of many diseases. However, no information is available on the expression of microRNAs (miRNAs) in the serum of dogs infected with T. canis. In this study, RNA-seq analysis was performed to identify the serum miRNA profiles in Beagle dogs infected with T. canis at different stages of infection. A total of 3, 25 and 25 differently expressed miRNAs (DEmiRNAs) were identified in dog serum at 24 h post-infection (hpi), 10 days post-infection (dpi) and 36 dpi, respectively, such as cfa-let-7g, cfa-miR-16, cfa-miR-92b, cfa-miR-93, cfa-miR-122, cfa-miR-485 and cfa-miR-451. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these miRNAs could regulate the pathways related to parasitic infectious diseases and immune system, such as amoebiasis, toxoplasmosis, platelet activation, IL-17 signaling pathway and chemokine signaling pathway. These results provide a foundation to explore the underlying regulatory role of miRNAs in definitive hosts after T. canis infection.