Variation of Mitogen-activated protein kinase ((MEK3) and NOD2 receptor transcripts in Toxoplasma gondii infection: a preliminary comparative analysis

Abstract

Toxoplasma gondii is a parasite infecting almost all warm-blooded animals and 30% of the world’s human population. Among domesticated animals, small ruminants and swine are the most often infected species. Most severe consequences arise during early pregnancy and transplacental transmission to the fetus, causing conspicuous loss for breeders. Recognizing early transcriptional signatures of infection might be interesting not only for veterinary but also for human medicine. Most of investigations were reported in mice following in vitro infection while poor results are available about other species, naturally infected by the parasite [1]. Aim of this study was to compare the expression profile of MEK3 and NOD2 proteins, involved in the immune response to the parasite, among naturally infected and uninfected animals (control) of various species. Tissues were collected post mortem from 11 horses, 10 sheep, 15 pigs. Infection was assessed by immunoenzymatic assay. MEK3 and NOD2 mRNAs were evaluated by Real-time PCR in the encephalic trunk and diaphragm. Results were processed by ΔΔCt method and expressed as fold change among the target mRNAs, normalized to β-actin. Performed analysis revealed an increase of MEK3 mRNA in muscular and encephalic tissues and of NOD2 mRNA in brainstem of both infected sheep and swine. Moreover, a comparative analysis among healthy animals of afore mentioned species revealed higher Nod2 mRNA levels in brainstem of equine compared to sheep and pigs. Both proteins are involved in key molecular mechanisms of immune responses, such as apoptosis regulation, therefore, detected variations among infected and uninfected susceptible animals (MEK3, NOD2) as well as higher physiological amount of NOD2 mRNA in brainstem of less susceptible species compared to more susceptible ones might provide interesting insights into the immune response to T. gondii-related transcriptome of intermediate hosts. 1. Cong W. et al. Frontiers in Immunology (2018) 9, 240