Activity of the Histone Deacetylase Inhibitor FR235222 on Toxoplasma gondii: Inhibition of Stage Conversion of the Parasite Cyst Form and Study of New Derivative Compounds

摘要

Bradyzoite-to-tachyzoite conversion plays a role in the pathogenesis of recrudescence of ocular toxoplasmosis and disease in immunocompromised persons. The currently available medicines are ineffective on cysts and fail to prevent reactivation of latent toxoplasmosis. A previous study showed that the histone deacetylase inhibitor has a dramatic effect on tachyzoite growth and induces tachyzoite-to-bradyzoite conversion in vitro. The present study shows that can target in vitro-converted cysts and bradyzoites. Moreover, the compound is active on ex vivo T. gondii cysts. Free bradyzoites isolated after lysis of the cell wall did not proliferate in vitro when the cyst was treated with . The results imply that this compound is able to cross the T. gondii cystic cell wall. Fluorescent labeling shows that the compound impairs the capacity of the bradyzoites to convert without damaging the cyst wall integrity. In vivo inoculation of formerly treated cysts fails to infect mice when these cysts were treated with . We used our structural knowledge of and its target, T. gondii HDAC3, to synthesize new derivative compounds. We identified two new molecules that are highly active against tachyzoites. They harbor a better selectivity index that is more suitable for a future in vivo approach. These results identify and its derivatives as new lead compounds in the range of therapeutics available for acute and chronic toxoplasmosis.