Studio comparato di profili di espressione in risposte biochimiche e biomolecolari all’esposizione a Toxoplasma gondii in varie Specie animali”

Toxoplasma gondii is a widespread protozoan causing a foodborn zoonosis among the most common in Europe. In addition to causing considerable economic losses for breeders, mainly linked to abortions, it is also a major risk factor for pregnant women and immunocompromised subjects. Even though toxoplasmosis still remains underestimated, various research teams have recently demonstrated or speculated a correlation between latent infection and many pathologies affecting the nervous system.. Virtually all species can be infected, but the parasite spreads more easily and causes more severe symptoms among some species than others (e.g. Horse). Due to this inter- species variation in terms of susceptibility to toxoplasmosis and severity of its symptoms, would be interesting, both for human and animal medicine, to investigate which host neuroendocrine and molecular pathways are modulated by T. gondii and involved in this phenomenon. A correlation between nervous system impairment caused by T. gondii and serotonin alterations can be hypothesized but, while contrasting data are available on serotonin levels at target tissues, no data on serotonin plasma levels were found. Many molecules have been proved to be somehow linked to cell response to T. gondii, but most of the analysis have been performed on cultured cells or in mice. Confirming the same results in other animal species, naturally infected by the parasite, would be interesting. On the basis of the aforementioned observations, the aim of this project was to assess the variation of plasma serotonin concentration and of some molecules’ expression profiles among infected and uninfected animals (control group) of various species. From the analysis of hematological parameters, significantly higher amounts of some white cell line elements were revealed in infected animals compared to control groups, but the specific altered cell component changed among species. Circulating serotonin levels were assessed by ELISA in 66 horses, 57 sheep and 43 cattle. No significant variation was observed between infected and uninfected cattle, while plasma serotonin was significantly higher in infected sheep compared to uninfected ones and, conversely, the same parameter was lower in infected horses compared to control group. Expression profiles were evaluated in some parasite target tissues (encefalic trunk, diaphragm and bowel) of 11 horses, 10 sheep, 15 cattle and 15 pigs. This analysis has revealed some interesting molecule variations among infected and uninfected animals as well as in terms of physiological expression profiles of healthy horses compared to other species. Further analysis should be performed to assess if these variations may influence the abundance of corresponding proteins, downstream molecular pathways and, subsequently, physiological and immune host responses to T. gondii.