title: Reduction of Toxoplasma gondii Development Due to Inhibition of Parasite Antioxidant Enzymes by a Dinuclear Iron(III) Compound.
abstract: Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan that can infect a wide range of vertebrate cells. Here, we describe the cytotoxic effects of the dinuclear iron compound [Fe(HPCINOL)(SO4)]2-μ-oxo, in which HPCINOL is the ligand 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, on T. gondii infecting LLC-MK2 host cells. This compound was not toxic to LLC-MK2 cells at concentrations of up to 200 μM but was very active against the parasite, with a 50% inhibitory concentration (IC50) of 3.6 μM after 48 h of treatment. Cyst formation was observed after treatment, as indicated by the appearance of a cyst wall, Dolichos biflorus lectin staining, and scanning and transmission electron microscopy characteristics. Ultrastructural changes were also seen in T. gondii, including membrane blebs and clefts in the cytoplasm, with inclusions similar to amylopectin granules, which are typically found in bradyzoites. An analysis of the cell death pathways in the parasite revealed that the compound caused a combination of apoptosis and autophagy. Fluorescence assays demonstrated that the redox environment in the LLC-MK2 cells becomes oxidant in the presence of the iron compound. Furthermore, a reduction in superoxide dismutase and catalase activities in the treated parasites and the presence of reactive oxygen species within the parasitophorous vacuoles were observed, indicating an impaired protozoan response against these radicals. These findings suggest that this compound disturbs the redox equilibrium of T. gondii, inducing cystogenesis and parasite death.
authors.affiliation: Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Portes
authors.affiliation: Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil.
authors.forename: T G
authors.initials: TG
authors.lastname: Souza
authors.affiliation: Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
authors.forename: T A T
authors.initials: TA
authors.lastname: dos Santos
authors.affiliation: Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
authors.forename: L L R
authors.initials: LL
authors.lastname: da Silva
authors.affiliation: Laboratório de Citotoxicidade e Genotoxicidade, Departamento de Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: T P
authors.initials: TP
authors.lastname: Ribeiro
authors.affiliation: Laboratório de Citotoxicidade e Genotoxicidade, Departamento de Bioquímica, Instituto de Química, UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: M D
authors.initials: MD
authors.lastname: Pereira
authors.affiliation: Laboratório de Ciências Químicas, Centro de Ciência e Tecnologia, UENF, Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Horn
authors.affiliation: Laboratório de Ciências Químicas, Centro de Ciência e Tecnologia, UENF, Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Fernandes
authors.affiliation: Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
authors.forename: R A
authors.initials: RA
authors.lastname: DaMatta
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem (INBEB) and Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), UFRJ, Rio de Janeiro, RJ, Brazil Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro), Duque de Caxias, RJ, Brazil.
authors.forename: W
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Laboratório de Tecnologia em Cultura de Células, Centro Universitário Estadual da Zona Oeste (UEZO), Rio de Janeiro, RJ, Brazil seabrash@gmail.com.
authors.forename: S H
authors.initials: SH
authors.lastname: Seabra
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000037:antagonists & inhibitors / Q000378:metabolism; D002460:Cell Line; D003049:Coccidiostats / Q000737:chemistry / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology*; D008253:Macaca mulatta; D046529:Microscopy, Electron, Transmission; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000378:metabolism; D014122:Toxoplasma / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: C000610590:(Fe(HPCINOL)(SO4))2-mu-oxo; D000975:Antioxidants; D003049:Coccidiostats; D004791:Enzyme Inhibitors; D005290:Ferric Compounds; D017382:Reactive Oxygen Species; D002374:Catalase; D013482:Superoxide Dismutase