Vilos placentários humanos modulam a susceptibilidade de células HUVEC (células endoteliais da veia umbilical humana) à infecção por Toxoplasma gondii

Abstract

Toxoplasma gondii has the property of invading tissues and crossing biological barriers in infected humans. The parasite reaches immune-privileged sites such as the placenta and infects different populations of placental cells as well as endothelial cells. In this study, we investigated the influence of culture medium (conditioned medium) from chorionic villi explants, infected or not by T. gondii, on human umbilical vein endothelial cells (HUVEC). HUVEC cells were infected with T. gondii RH (2F1) tachyzoites and treated with conditioned medium infected or not infected with T. gondii. The intracellular proliferation of the parasite was analyzed by colorimetric β-galactosidase assay and cytokine dosage by ELISA. Permeability and electrical resistance (TEER) were also analyzed using fluorescence assay in transwell culture. ZO-1 protein expression was performed by immunofluorescence and ICAM-1 expression by Western blotting. Infected cells treated with conditioned medium had a high parasite load, greater production of pro-inflammatory cytokine and greater permeability in opposition to transepithelial electrical resistance. Treatment with infected or uninfected conditioned medium, as well as infection of HUVEC cells induced lower expression of ZO-1. ICAM-1 expression was altered by the conditioned medium, regardless of infection, in HUVEC cells, infected or not. Inhibition of the adhesion protein ICAM-1 increased parasite proliferation in HUVEC cells. Taken together, the data demonstrated that T. gondii infection and treatment with infected conditioned media alter cytokine secretion and electrical resistance, increasing cell permeability due to an alteration of ICAM-1 and decreased expression of ZO- 1 thus facilitating parasitic proliferation in HUVEC cells.