No abstract

Oxygen derivatives that comprise the large family of reactive oxygen species (ROS) are actively involved in placental biology. They are generated at the maternal-fetal interface at the level of decidual, trophoblast and mesenchymal components. In normal conditions, ROS produced in low concentrations participate in different functions as signalling molecules, regulating activation of redox-sensitive transcription factors and protein kinases involved in cell survival, proliferation and apoptosis, hence much of cell functioning. Physiological ROS generation is also associated with such defence mechanisms as phagocytosis and microbiocidal activities. In mice, particularly but not exclusively, trophoblast cells phagocytose intensively during implantation and post-implantation periods and express enzymic machinery to address a ROS-producing response to changes in the environment. The cells directly associated with ROS production are trophoblast giant cells, which mediate each and every relationship with the maternal organism. In this review, the production of ROS by the implanting mouse trophoblast is discussed, focusing on NADPH oxidase expression, regulatory mechanisms and similarities with NOX2 from phagocytes. Some of the current controversies are assessed by attempting to integrate data from studies in human trophoblast and mouse models.

Cytochemical localization of hydrogen peroxide-generating sites suggests NADPH (nicotinamide adenine dinucleotide 3-phosphate [reduced form]) oxidase expression at the maternal-fetal interface. To explore this possibility, we have characterized the expression and activity of the NADPH oxidase complex in trophoblast cells during the postimplantation period. Implantation sites and ectoplacental cones (EPCs) from 7.5-gestational day embryos from CD1 mice were used as a source for expression analyses of NADPH oxidase catalytic and regulatory subunits. EPCs grown in primary culture were used to investigate the production of superoxide anion through dihydroxyethidium oxidation in confocal microscopy and immunohistochemical assays. NADPH subunits Cybb (gp91phox), Cyba (p22phox), Ncf4 (p40phox), Ncf1 (p47phox), Ncf2 (p67phox), and Rac1 were expressed by trophoblast cells. The fundamental subunits of membrane CYBB and cytosolic NCF2 were markedly upregulated after phorbol-12-myristate-13-acetate (PMA) treatment, as detected by quantitative real-time PCR, Western blotting, and immunohistochemistry. Fluorescence microscopy imaging showed colocalization of cytosolic and plasma membrane NADPH oxidase subunits mainly after PMA treatment, suggesting assembly of the complex after enzyme activation. Cultured EPCs produced superoxide in a NADPH-dependent manner, associating the NADPH oxidase-mediated superoxide production with postimplantation trophoblast physiology. NADPH-oxidase cDNA subunit sequencing showed a high degree of homology between the trophoblast and neutrophil isoforms of the oxidase, emphasizing a putative role for reactive oxygen species production in phagocytic activity and innate immune responses.

No abstract

The use of immunosuppressive drugs guarantees the vitality of the graft and allows gestation in spite of intercurrences such as prematurity and intrauterine growth restriction. However, little is known about the direct effects of immunosuppressive drugs on placental cells. We investigated the effects of immunosuppressive drugs in the chorionic villous explants from human term placentas of healthy gestations. Human placental explants from term gestations (37-39 week gestational age, n = 12) were exposed to cyclosporine A (CSA, 0, 62.5, 125, 1250 ng/mL) or azathioprine (AZA, 0, 5, 10, 100 ng/mL) separately or, in combination for up to 48 hours. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed a significant decrease in the explant metabolic activity between AZA and the control group (24 hours, 100 ng/mL, 48 hours, all concentrations, P < .005). Cyclosporin A (CsA) reduced cell activity when associated with AZA (48 hours, P < .005). Fibrinoid deposits increased in AZA-treated explants alone (5 ng/mL, 48 hours; 10 ng/mL, 24-48 hours; P < .005) or when associated with CsA (10 AZA/125 CsA, P < .05), whereas in CsA treatment alone, there was an augment in syncytial knots (24-48 hours, P < .005). The sFLT1 gene (24 hours, P < .05) and protein ( P < .005) expression increased in AZA and CsA-treatments separately or in combination ( P < .05). Placental growth factor increased in AZA (24 hours, 10 ng/mL) and CsA (125 ng/mL; P < .05). In conclusion, our data indicate that AZA primarily acts on the villous metabolism, perturbing placental homeostasis. Since these drugs may alter the balance of angiogenic factors in its selection for clinical application, their impact on the behavior of placental villous should be considered.