Stage-specific expression of immune-related redox metabolism genes in Rhipicephalus (Boophilus) microplus following Theileria equi infection

Equine piroplasmosis is a major disease affecting horses, and Theileria equi is one of its etiological agents. In Brazil, Rhipicephalus microplus is the only tick species with a confirmed vectorial capacity to transmit T. equi. However, the immunological mechanisms involved in this pathogen-vector interface are still unclear. The oxidative response is an important immunological tool for controlling infections. This study aimed to evaluate the differential expression of genes related to redox metabolism in R. microplus in response to T. equi infection in the larva and nymph stages and in the tissues (midgut and salivary glands) of engorged female ticks. The results suggest that the transcriptional profiles of genes involved in the redox metabolism of R. microplus in response to T. equi infection are tissue-specific. The genes dual oxidase-1, dual oxidase-2, and catalase were upregulated in response to T. equi infection in both the midgut and salivary glands, indicating that they may play a relevant role in regulating the oxidative balance during the colonization of the parasite in the adult stage. In the larval and nymph stages of R. microplus, infection with T. equi did not significantly stimulate the differential expression of the analyzed genes. The results obtained in this study highlight the molecular immunological mechanisms involved in the different evolutionary stages of R. microplus in response to T. equi infection and contribute to the identification of key molecules for the development of new tools for the prevention and control of equine piroplasmosis.