Differential Spleen miRNA Expression Profile of Beagle Dogs Infected with Toxocara canis

SIMPLE SUMMARY: As one of the neglected parasitic zoonoses, toxocariasis has gained increasing international attention. To date, however, little is known about the spleen microRNAs (miRNA) expression profiling in definitive or paratenic hosts after Toxocara canis infection. In this study, we conducted sequencing-based transcriptome profiling of miRNA expression in the spleen of Beagle puppies after T. canis infection to understand the potential biological roles of the altered miRNAs. Some differentially expressed miRNAs (DEmiRNAs) were identified after T. canis infection. The transcriptional profiling data suggested that the DEmiRNAs play significant roles in the pathogenesis of toxocariasis. ABSTRACT: Toxocara canis is an unnoticed zoonotic helminth that causes severe disease in animals and humans. The spleen has a wide range of immunological functions in protecting the host against infection by many pathogens, but the function of the spleen in T. canis infection is still to be clarified, especially for the role of spleen microRNAs (miRNAs). In this study, deep sequencing of spleen RNA samples of 18 Beagle puppies was conducted to uncover the miRNAs expression profiling at 24 h post-infection (hpi), 96 hpi, and 36 days post infection (dpi). A total of 20, 34, and 19 differentially expressed miRNAs (DEmiRNAs) were identified at 24 hpi, 96 hpi, and 36 dpi, respectively. These DEmiRNAs (e.g., cfa-miR-206, cfa-miR-331, and cfa-miR-339) could play critical roles in Beagle puppies against T. canis infection, such as influencing inflammatory and immune-related cells and cytokines, by regulating target genes that are tightly associated with host immune function and enriched in immune response and immune pathways based on GO annotation and KEGG enrichment analysis. The current study discovered marked alterations of spleen miRNAs after T. canis infection, with potential effects on the pathogenesis of toxocariasis.