Novel drug candidates targeting Toxoplasma gondii in maternal-fetal interface models

Rafael Oliveira¹Natália Carine Lima¹Marcos Paulo Oliveira Almeida¹Joed Pires De Lima Júnior¹Guilherme De Souza¹Matheus Carvalho Barbosa¹Guilherme Vieira Faria¹Marina Paschoalino¹ROSIANE ALVES²Angelica Oliveira Gomes³Juliana Quero Reimão⁴Bellisa Freitas Barbosa¹Samuel Cota Teixeira¹Eloisa Amália Vieira Ferro^1*

• ¹Federal University of Uberlandia, Uberlândia, Brazil
• ²Universidade do Estado de Minas Gerais, Belo Horizonte, Brazil
• ³Universidade Federal do Triangulo Mineiro, Uberaba, Brazil
• ⁴Faculdade de Medicina de Jundiai, Jundiaí, Brazil

Introduction: Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii. Infection during pregnancy can lead to congenital toxoplasmosis, associated with severe outcomes such as fetal abnormalities, stillbirths, and miscarriage. Current treatment options for congenital toxoplasmosis are several limitations, including low efficacy in the chronic phase of the disease and the potential limited by potential fetal toxicity, including bone marrow suppression and teratogenic effects. Therefore, there is an urgent need for more effective and safer therapeutic alternatives. Medicines for Malaria Venture (MMV) offers a collection of bioactive compounds with antiparasitic potential for drug repurposing. Methods: In this study, we evaluated three MMV Pathogen Box compounds – MMV675968, MMV022478, and MMV021013 – for their ability to control T. gondii infection in human trophoblastic cells (BeWo) and third-trimester placental villous explants. We assessed compound toxicity, effects on the parasite's lytic cycle (including adhesion and infection), alterations in parasite morphology, and the host immune response through cytokine quantification. Results: Non-toxic concentrations of all the three compounds irreversibly inhibited parasite proliferation and interfered with early stages of the lytic cycle, including adhesion and infection. Moreover, treated T. gondii tachyzoites exhibited membrane disruption, cytoplasmic degradation, and organelle disorganization. Cytokine profile indicated that compound treatment promoted an anti-inflammatory immune response, primarily by reducing IL-8 levels. Importantly, these compounds also effectively controlled T. gondii infection in human placental explants without inducing cytotoxicity. Conclusion: Taken together, our findings support the potential of MMV675968, MMV022478, and MMV021013 as promising drug candidates for the treatment of congenital toxoplasmosis. MMV021013 stands out as the most promising compound, combining high predicted gastrointestinal absorption and blood-brain barrier permeability, with no predicted mutagenic, tumorigenic, irritant, or reproductive effects.