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Crosstalk between trophoblast and monocytes is essential for gestational success, and it can be compromised in congenital toxoplasmosis. Cell death is one of the mechanisms involved in the maintenance of pregnancy, and this study aimed to evaluate the role of trophoblast in the modulation of monocyte cell death in the presence or absence of Toxoplasma gondii infection. THP-1 cells were stimulated with supernatants of BeWo cells and then infected or not with T. gondii. The supernatants were collected and analyzed for the secretion of human Fas ligand, and cells were used to determine cell death and apoptosis, cell death receptor, and intracellular proteins expression. Cell death and apoptosis index were higher in uninfected THP-1 cells stimulated with supernatants of BeWo cells; however, apoptosis index was reduced by T. gondii infection. Macrophage migration inhibitory factor (MIF) and transforming growth factor (TGF)-β1, secreted by BeWo cells, altered the cell death and apoptosis rates in THP-1 cells. In infected THP-1 cells, the expression of Fas/CD95 and secretion of FasL was significantly higher; however, caspase 3 and phosphorylated extracellular-signal-regulated kinase (ERK1/2) were downregulated. Results suggest that soluble factors secreted by BeWo cells induce cell death and apoptosis in THP-1 cells, and Fas/CD95 can be involved in this process. On the other hand, T. gondii interferes in the mechanism of cell death and inhibits THP-1 cell apoptosis, which can be associated with active caspase 3 and phosphorylated ERK1/2. In conclusion, our results showed that human BeWo trophoblast cells and T. gondii infection modulate cell death in human THP-1 monocyte cells., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Trophoblast infection by Toxoplasma gondii plays a pivotal role in the vertical transmission of toxoplasmosis. Here, we investigate whether the antibiotic therapy with azithromycin, spiramycin and sulfadiazine/pyrimethamine are effective to control trophoblast infection by two Brazilian T. gondii genotypes, TgChBrUD1 or TgChBrUD2. Two antibiotic protocols were evaluated, as follow: i) pre-treatment of T. gondii-tachyzoites with selected antibiotics prior trophoblast infection and ii) post-treatment of infected trophoblasts. The infection index/replication and the impact of the antibiotic therapy on the cytokine milieu were characterized. It was observed that TgChBrUD2 infection induced lower infection index/replication as compared to TgChBrUD1. Regardless the therapeutic protocol, azithromycin was more effective to control the trophoblast infection with both genotypes when compared to conventional antibiotics. Azithromycin induced higher IL-12 production in TgChBrUD1-infected cells that may synergize the anti-parasitic effect. In contrast, the effectiveness of azithromycin to control the TgChBrUD2-infection was not associated with the IL-12 production. BeWo-trophoblasts display distinct susceptibility to T. gondii genotypes and the azithromycin treatment showed to be more effective than conventional antibiotics to control the T. gondii infection/replication regardless the parasite genotype., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Considering that interleukin 10 (IL10), transforming growth factor beta1 (TGFB1), and interferon gamma (IFNG) are involved in the susceptibility of BeWo trophoblast cells to Toxoplasma gondii infection, the aim of the present study was to investigate the effector mechanisms triggered by these cytokines in the control of T. gondii in BeWo cells. For this purpose, infected/uninfected BeWo cells were treated with IL10, TGFB1 (50 ng/ml), and IFNG (20 or 100 ng/ml) in order to verify the phosphorylation of signal transducers and activators of transcription 1 (STAT1), STAT3, and Smad2, parasite intracellular proliferation, as well as the Th1/Th2/IL17A cytokine production. The treatment of BeWo cells with IL10 and TGFB1 favored T. gondii proliferation, and these findings were associated with STAT3 and Smad2 phosphorylation, respectively (P < 0.05). Also, these cytokine treatments were able to down-modulate TNF alpha (TNFA) and IL6 production (P < 0.05). Low concentration of IFNG was unable to control T. gondii infection but was able to trigger STAT1 phosphorylation and up-regulate IL6 and IL17A production; whereas a high concentration of IFNG was unable to activate STAT1 but down-modulated IL6 and TNFA and increased T. gondii proliferation (P < 0.05). IL10, TGFB1, and IFNG regulate a differential T. gondii proliferation in BeWo cells because they distinctly trigger intracellular signaling pathways and cytokine production, especially IL6 and TNFA. Our data open new windows to understand the mechanisms triggered by IL10, TGFB1, and IFNG at the maternal-fetal interface in the presence of T. gondii, contributing to recognizing the importance of these effector mechanisms involved in the vertical transmission of this parasite., (© 2015 by the Society for the Study of Reproduction, Inc.)

The facultative intracellular bacterial pathogens Listeria monocytogenes and Salmonella enterica have evolved multiple strategies to invade a large panel of mammalian cells. These pathogens use the host cell actin system for invasion and became a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. The key signaling component that these pathogens use to orchestrate actin remodeling is the Arp2/3 complex, which is related to polymerization of actin filaments. These bacterial pathogens are able to trigger distinct invasion mechanisms. On the one hand, L. monocytogenes invade a host cell in a way dependent on the specific interactions between bacterial and host cell proteins, which in turn activate the host cell actin polymerizing machinery that culminates with bacterial internalization. Also, Listeria escapes from the newly formed parasitophorous vacuole and moves among adjacent cells by triggering actin polymerization. On the other hand, Salmonella invades a host cell by delivering into the cytoplasm virulence factors which directly interact with host regulators of actin polymerization which leads to bacterial uptake. Moreover, Salmonella avoids vacuole lyses and modulates the early and late endosomal markers presented in the vacuole membrane. This mini-review focuses on the different pathways that L. monocytogenes and S. enterica activate to modulate the actin cytoskeleton in order to invade, to form the parasitophorous vacuole, and to migrate inside host cells., (Copyright © 2011 Elsevier GmbH. All rights reserved.)

Because macrophage migration inhibitory factor (MIF) is a key cytokine in pregnancy and has a role in inflammatory response and pathogen defense, the objective of the present study was to investigate the effects of MIF in first- and third-trimester human placental explants infected with Toxoplasma gondii. Explants were treated with recombinant MIF, IL-12, interferon-γ, transforming growth factor-β1, or IL-10, followed by infection with T. gondii RH strain tachyzoites. Supernatants of cultured explants were assessed for MIF production. Explants were processed for morphologic analysis, immunohistochemistry, and real-time PCR analysis. Comparison of infected and stimulated explants versus noninfected control explants demonstrated a significant increase in MIF release in first-trimester but not third-trimester explants. Tissue parasitism was higher in third- than in first-trimester explants. Moreover, T. gondii DNA content was lower in first-trimester explants treated with MIF compared with untreated explants. However, in third-trimester explants, MIF stimulus decreased T. gondii DNA content only at the highest concentration of the cytokine. In addition, high expression of MIF receptor was observed in first-trimester placental explants, whereas MIF receptor expression was low in third-trimester explants. In conclusion, MIF was up-regulated and demonstrated to be important for control of T. gondii infection in first-trimester explants, whereas lack of MIF up-regulation in third-trimester placentas may be involved in higher susceptibility to infection at this gestational age., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)