Manipulating the Manipulator: Genetically modifying T. gondii to degrade rather than produce dopamine could be used to treat symptoms of schizophrenia

Abstract

The host manipulating parasite Toxoplasmic gondiicauses the vector-borne disease, Toxoplasmosis. During the chronic stage of infection, after cysts formation, the parasites release high levels of tyrosine hydroxylase. This enzyme causes an increase in dopamine levels as it is a known limiting factor of dopamine production. The TgAaaH1 and TgAaaH2 genes found in the T. gondiigenome are known to be responsible for this production. Increased dopamine levels have been shown to correlatewithschizophrenic symptoms, such as hallucinations and delusions. The two genes can be removed and replaced with the COMT gene. This gene regulates dopamine levels by degrading dopamine. The genetically modified T. gondiican then be administered to patients who show schizophrenic symptoms but are negative for toxoplasmosis.