Alessandra Monteiro Rosini

Toxoplasma gondii is a globally distributed protozoan parasite and a major cause of congenital infections, particularly in South America. Current therapies for congenital toxoplasmosis are limited by toxicity, long treatment regimens, and suboptimal efficacy, highlighting the urgent need for safer and more effective alternatives. In this study, we evaluated the antiparasitic effects of crude ethanolic extract of Brazilian Red Propolis (BRP) and its isolated compounds, focusing on 7-O-methylvestitol, in human trophoblast (BeWo) cells and third-trimester placental explants. Both BRP and 7-O-methylvestitol significantly reduced T. gondii adhesion, invasion, and intracellular replication, without compromising host cell viability. Ultrastructural analyses revealed irreversible parasite damage, and cytokine profiling demonstrated immunomodulatory effects, with enhanced production of interleukin (IL)-6, IL-8, and macrophage migration inhibitory factor (MIF) in BeWo cells and downregulation of IL-6, MIF, and tumor Necrosis Factor (TNF) in infected placental villi. Notably, 7-O-methylvestitol reproduced and, in some assays, surpassed the antiparasitic activity of BRP, suggesting it as a key bioactive constituent responsible for the therapeutic potential of the extract. These findings support the identification of 7-O-methylvestitol as a promising lead compound for structure-based drug design and repositioning strategies, advancing the development of novel, safe, and targeted therapies against congenital toxoplasmosis.

Toxoplasmosis is an alarming public health problem that affects more than one-third of the world’s population. In our work, we investigated the antiparasitic effects of catalytically active [BpMP-I and Jararhagin (Jar)] and catalytically inactive [Jararhagin-C (Jar-C)] snake venom metalloproteinases (SVMPs) in human HeLa cells. These toxins impaired the parasite invasion and intracellular growth, and modulated IL-6, IL-8, and MIF cytokines that control the cell susceptibility and response against T. gondii. Furthermore, we verified that the antiprotozoal activities are not restricted to the presence of the proteolytic domain, and the adhesive domains participate in the control of T. gondii infection. Also, by analyzing the structures of Jar and Jar-C through molecular modeling and dynamics, we observed that the adhesive domains in Jar-C are more exposed due to the absence of the proteolytic domain, which could favor the interaction with different targets. Our investigation on the role of SVMP domains in combating T. gondii infection highlights their potential application as biotechnological tools for creating more effective treatments for toxoplasmosis.