Differential MiRNA Expression Profiles in the Bone Marrow of Beagle Dogs at Different Stages of Toxocara Canis Infection

Background: Toxocara canis is distributed worldwide, posing a serious threat to both human and dog health; however, the pathogenesis of T. canis infection in dogs remains unclear. In this study, the changes in microRNA (miRNA) expression profiles in the bone marrow of Beagle dogs were investigated by RNA-seq and bioinformatics analysis.

Results: Thirty-nine differentially expressed (DE) miRNAs (DEmiRNAs) were identified in this study. Among these, four DEmiRNAs were identified at 24 h post-infection (hpi) and all were up-regulated; eight DEmiRNAs were identified with two up-regulated miRNAs and six down-regulated miRNAs at 96 hpi; 27 DEmiRNAs were identified with 13 up-regulated miRNAs and 14 down-regulated miRNAs at 36 days post-infection (dpi). Among these DEmiRNAs, cfa-miR-193b participates in the immune response by regulating the target gene cd22 at 24 hpi. The novel_328 could participate in the inflammatory and immune responses through regulating the target genes tgfb1 and tespa1, enhancing the immune response of the host and inhibiting the infection of T. canis at 96 hpi. In addition, cfa-miR-331 and novel_129 were associated with immune response and self-protection mechanisms at 36 dpi. 20 pathways were significantly enriched by KEGG pathway analysis, most of which were related to inflammatory response, immune response and cell differentiation, such as Cell adhesion molecules (CAMs), ECM-receptor interaction and Focal adhesion.

Conclusions: These findings suggested that miRNAs of Beagle dog bone marrow play important roles in the pathogenesis of T. canis infection in dogs and provided useful resources to better understand the interaction between T. canis and the hosts.