Copaifera spp. oleoresins and two isolated compounds (ent-kaurenoic and ent-polyalthic acid) inhibit Toxoplasma gondii growth in vitro.

Toxoplasmosis affects about one-third of the world's population. The disease treatment methods pose several side effects and do not efficiently eliminate the parasite, making the search for new therapeutic approaches necessary. We aimed to assess the anti-Toxoplasma gondii activity of four Copaifera oleoresins (ORs) and two isolated diterpene acids, named ent-kaurenoic and ent-polyalthic acid. We used HeLa cells as an experimental model of toxoplasmosis. Uninfected and infected HeLa cells were submitted to the treatments, and the parasite intracellular proliferation, cytokine levels and ROS production were measured. Also, tachyzoites were pre-treated and the parasite invasion was determined. Finally, an in silico analysis was performed to identify potential parasite targets. Our data show that the non-cytotoxic concentrations of ORs and diterpene acids controlled the invasion and proliferation of T. gondii in HeLa cells, thus highlighting the possible direct action on parasites. In addition, some compounds tested controlled parasite proliferation in an irreversible manner. An additional and non-exclusive mechanism of action involves the modulation of host cell components, by affecting the upregulation of the IL-6. Additionally, molecular docking suggested that ent-polyalthic acid has a high affinity for the active site of the TgCDPK1 protein. Copaifera ORs have great antiparasitic activity against T. gondii, and this effect can be partially explained by the presence of the isolated compounds ent-kaurenoic and ent-polyalthic acid.

Systematic Review and Meta-Analysis of Congenital Toxoplasmosis Diagnosis: Advances and Challenges.

Objective: To understand how congenital toxoplasmosis (CT) diagnosis has evolved over the years, we performed a systematic review and meta-analysis to summarize the kind of analysis that has been employed for CT diagnosis. Methods: PubMed and Lilacs databases were used in order to access the kind of analysis that has been employed for CT diagnosis in several samples. Our search combined the following combining terms: "congenital toxoplasmosis" or "gestational toxoplasmosis" and "diagnosis" and "blood," "serum," "amniotic fluid," "placenta," or "colostrum." We extracted data on true positive, true negative, false positive, and false negative to generate pooled sensitivity, specificity, and diagnostic odds ratio (DOR). Random-effects models using MetaDTA were used for analysis. Results: Sixty-five articles were included in the study aiming for comparisons (75.4%), diagnosis performance (52.3%), diagnosis improvement (32.3%), or to distinguish acute/chronic infection phases (36.9%). Amniotic fluid (AF) and placenta were used in 36.9% and 10.8% of articles, respectively, targeting parasites and/or T. gondii DNA. Blood was used in 86% of articles for enzymatic assays. Colostrum was used in one article to search for antibodies. In meta-analysis, PCR in AF showed the best performance for CT diagnosis based on the highest summary sensitivity (85.1%) and specificity (99.7%) added to lower magnitude heterogeneity. Conclusion: Most of the assays being researched to diagnose CT are basically the same traditional approaches available for clinical purposes. The range in diagnostic performance and the challenges imposed by CT diagnosis indicate the need to better explore pregnancy samples in search of new possibilities for diagnostic tools. Exploring immunological markers and using bioinformatics tools and T. gondii recombinant antigens should address the research needed for a new generation of diagnostic tools to face these challenges.

Trypanosoma cruzi P21 recombinant protein modulates Toxoplasma gondii infection in different experimental models of the human maternal-fetal interface.

Introduction: Toxoplasma gondii is the etiologic agent of toxoplasmosis, a disease that affects about one-third of the human population. Most infected individuals are asymptomatic, but severe cases can occur such as in congenital transmission, which can be aggravated in individuals infected with other pathogens, such as HIV-positive pregnant women. However, it is unknown whether infection by other pathogens, such as Trypanosoma cruzi, the etiologic agent of Chagas disease, as well as one of its proteins, P21, could aggravate T. gondii infection. Methods: In this sense, we aimed to investigate the impact of T. cruzi and recombinant P21 (rP21) on T. gondii infection in BeWo cells and human placental explants. Results: Our results showed that T. cruzi infection, as well as rP21, increases invasion and decreases intracellular proliferation of T. gondii in BeWo cells. The increase in invasion promoted by rP21 is dependent on its binding to CXCR4 and the actin cytoskeleton polymerization, while the decrease in proliferation is due to an arrest in the S/M phase in the parasite cell cycle, as well as interleukin (IL)-6 upregulation and IL-8 downmodulation. On the other hand, in human placental villi, rP21 can either increase or decrease T. gondii proliferation, whereas T. cruzi infection increases T. gondii proliferation. This increase can be explained by the induction of an anti-inflammatory environment through an increase in IL-4 and a decrease in IL-6, IL-8, macrophage migration inhibitory factor (MIF), and tumor necrosis factor (TNF)-α production. Discussion: In conclusion, in situations of coinfection, the presence of T. cruzi may favor the congenital transmission of T. gondii, highlighting the importance of neonatal screening for both diseases, as well as the importance of studies with P21 as a future therapeutic target for the treatment of Chagas disease, since it can also favor T. gondii infection.

Rottlerin impairs early and late steps of Toxoplasma gondii infection in human trophoblast cells and villous explants.

Congenital toxoplasmosis, caused by the opportunistic protozoan parasite T. gondii, can cause stillbirths, miscarriages and fetal abnormalities, as well as encephalitis and chorioretinitis in newborns. Available treatment options rely on antiparasitic drugs that have been linked to serious side effects, high toxicity and the development of drug-resistant parasites. The search for alternative therapeutics to treat this disease without acute toxicity for the mother and child is essential for the advancement of current therapeutic procedures. The present study aimed to unravel the mode of the anti-T. gondii action of Rottlerin, a natural polyphenol with multiple pharmacological properties described. Herein, we further assessed the antiparasitic activity of Rottlerin against T. gondii infection on the human trophoblastic cells (BeWo cells) and, for the first time, on human villous explants. We found that non-cytotoxic doses of Rottlerin impaired early and late steps of parasite infection with an irreversible manner in BeWo cells. Rottlerin caused parasite cell cycle arrest in G1 phase and compromised the ability of tachyzoites to infect new cells, thus highlighting the possible direct action on parasites. An additional and non-exclusive mechanism of action of Rottlerin involves the modulation of host cell components, by affecting lipid droplet formation, mitochondrial function and upregulation of the IL-6 and MIF levels in BeWo cells. Supporting our findings, Rottlerin also controlled T. gondii proliferation in villous explants with low toxicity and reduced the IL-10 levels, a cytokine associated with parasite susceptibility. Collectively, our results highlighted the potential use of Rottlerin as a promising tool to prevent and/or treat congenital toxoplasmosis.

Polyalthic acid and oleoresin from Copaifera trapezifolia Hayne reduce Toxoplasma gondii growth in human villous explants, even triggering an anti-inflammatory profile.

Due to the lack of efficient antiparasitic therapy and vaccines, as well as emerging resistance strains, congenital toxoplasmosis is still a public health issue worldwide. The present study aimed to assess the effects of an oleoresin obtained from the species Copaifera trapezifolia Hayne (CTO), and an isolated molecule found in the CTO, ent-polyalthic acid (ent-15,16-epoxy-8(17),13(16),14-labdatrien-19-oic acid) (named as PA), against T. gondii infection. We used human villous explants as an experimental model of human maternal-fetal interface. Uninfected and infected villous explants were exposed to the treatments; the parasite intracellular proliferation and the cytokine levels were measured. Also, T. gondii tachyzoites were pre-treated and the parasite proliferation was determined. Our findings showed that CTO and PA reduced efficiently the parasite growth with an irreversible action, but without causing toxicity to the villi. Also, treatments reduced the levels of IL-6, IL-8, MIF and TNF by villi, what configures a valuable treatment option for the maintenance of a pregnancy in an infectious context. In addition to a possible direct effect on parasites, our data suggest an alternative mechanism by which CTO and PA alter the villous explants environment and then impair parasite growth, since the pre-treatment of villi resulted in lower parasitic infection. Here, we highlighted PA as an interesting tool for the design of new anti-T. gondii compounds.

Leaf hydroalcoholic extract and oleoresin from Copaifera multijuga control Toxoplasma gondii infection in human trophoblast cells and placental explants from third-trimester pregnancy.

The conventional treatment of congenital toxoplasmosis is mainly based on the combination of sulfadiazine and pyrimethamine. However, therapy with these drugs is associated with severe side effects and resistance, requiring the study of new therapeutic strategies. There are currently many studies with natural products, including Copaifera oleoresin, showing actions against some pathogens, as Trypanosoma cruzi and Leishmania. In the present study, we investigated the effects of the leaf hydroalcoholic extract and oleoresin from Copaifera multijuga against Toxoplasma gondii in human villous (BeWo) and extravillous (HTR8/SVneo) trophoblast cells, as well as in human villous explants from third-trimester pregnancy. For this purpose, both cells and villous explants were infected or not with T. gondii, treated with hydroalcoholic extract or oleoresin from C. multijuga and analyzed for toxicity, parasite proliferation, cytokine and ROS production. In parallel, both cells were infected by tachyzoites pretreated with hydroalcoholic extract or oleoresin, and adhesion, invasion and replication of the parasite were observed. Our results showed that the extract and oleoresin did not trigger toxicity in small concentrations and were able to reduce the T. gondii intracellular proliferation in cells previously infected. Also, the hydroalcoholic extract and oleoresin demonstrated an irreversible antiparasitic action in BeWo and HTR8/SVneo cells. Next, adhesion, invasion and replication of T. gondii were dampened when BeWo or HTR8/SVneo cells were infected with pretreated tachyzoites. Finally, infected and treated BeWo cells upregulated IL-6 and downmodulated IL-8, while HTR8/SVneo cells did not change significantly these cytokines when infected and treated. Finally, both the extract and oleoresin reduced the T. gondii proliferation in human explants, and no significant changes were observed in relation to cytokine production. Thus, compounds from C. multijuga presented different antiparasitic activities that were dependent on the experimental model, being the direct action on tachyzoites a common mechanism operating in both cells and villi. Considering all these parameters, the hydroalcoholic extract and oleoresin from C. multijuga can be a target for the establishment of new therapeutic strategy for congenital toxoplasmosis.

Macrophage Migration Inhibitory Factor contributes to drive phenotypic and functional macrophages activation in response to Toxoplasma gondii infection.

Cytokines are small molecules secreted by numerous cells. Macrophage Migration Inhibitory Factor (MIF) is a cytokine initially described due to its function of inhibiting random macrophage migration. Currently, new functions have been described for MIF, such as stimulating inflammatory functions in response to infections by microorganisms including, Toxoplasma gondii. However, the primordial MIF function related to macrophages has been little addressed. The main purpose of the study was to recapitulate MIF function on macrophages in response to T. gondii infection. To achieve this goal, peritoneal macrophages were collected from C57BL/6WT and Mif1-/- mice after recruitment with thioglycolate. Macrophages were cultured, treated with 4-Iodo-6-phenylpyrimidine (4-IPP), and infected or not by T. gondii for 24 h. Following this, the culture supernatant was collected for cytokine, urea and nitrite analysis. In addition, macrophages were evaluated for phagocytic activity and T. gondii proliferation rates. Results demonstrated that T. gondii infection triggered an increase in MIF production in the WT group as well as an increase in the secretion of IL-10, TNF, IFN-γ, IL-6 and IL-17 in the WT and Mif1-/- macrophages. Regarding the comparison between groups, it was detected that Mif1-/- macrophages secreted more IL-10 compared to WT. On the other hand, the WT macrophages produced greater amounts of TNF, IFN-γ, IL-6 and IL-17. Urea production was more pronounced in Mif1-/- macrophages while nitrite production was higher in WT macrophages. T. gondii showed a greater ability to proliferate in Mif1-/- macrophages and these cells also presented enhanced phagocytic activity. In conclusion, T. gondii infection induces macrophage activation inciting cytokine production. In presence of MIF, T. gondii infected macrophages produce pro-inflammatory cytokines compatible with the M1 activation profile. MIF absence caused a dramatic reduction in pro-inflammatory cytokines that are balanced by increased levels of urea and anti-inflammatory cytokines. These macrophages presented increased phagocytic capacity and shared features activation with the M2 profile.

The ethanolic extract of the fungus Trichoderma stromaticum decreases the Toxoplasma gondii replication in vitro and ameliorates the experimental toxoplasmosis in vivo.

Trichoderma are fungi that are well-known to inhibit the growth of a variety of plant pathogens. Currently, there is an increasing search for new drugs to treat toxoplasmosis. The aims of this study were to investigate the effect of ExtTs in the control of Toxoplasma gondii proliferation in vitro and the course of toxoplasmosis in a mouse model. Firstly, the cytotoxicity of the ExtTs was evaluated by cultivating macrophages with different concentrations of the extract and cell viability was assessed by the MTT assay. Next, the infectivity of the T. gondii treated with extract was analyzed by infecting J774 macrophages. To evaluate the effect of the ExtTs in vivo, C57BL/6 mice were infected orally with T. gondii, ME-49, treated daily with ExtTs, and clinical, biochemical and histological changes were monitored. It was demonstrated that the extract did not affect the host cellular viability and, the treatment of parasites with ExtTs altered their morphology and decreased their ability to proliferate inside macrophages. Additionally, the treatment of mice with ExtTs decreased the parasitism and inflammation in the small intestine and liver of infected mice in parallel with increased IL-10/TNF ratio systemically and prevented alterations to serum VLDL and triglyceride levels. Thus, ExtTs could be considered an alternative/complementary therapy to control toxoplasmosis.

LPS-mediated activation of TLR4 controls Toxoplasma gondii growth in human trophoblast cell (BeWo) and human villous explants in a dependent-manner of TRIF, MyD88, NF-κB and cytokines.

We evaluated the influence of the Toll-like receptor (TLR)-4 pathways on BeWo, JEG-3 and HTR-8/SVneo cells, as well as in human villous explants infected with Toxoplasma gondii. Cells and explants were stimulated with LPS for 24 or 48 h and processed for the MTT assay, and expression of TLR4 was evaluated by confocal microscopy. In addition, we used peptides that inhibit MyD88 or TRIF, and inhibitor to NF-κB. Finally, the parasite proliferation was verified, and ELISA was performed to verify the cytokine production. As results, LPS did not induce toxicity in cells and explants. However, LPS triggered a reduction in T. gondii proliferation only in BeWo cells and explants. Additionally, LPS downmodulated IL-10, TGF-ß1 and TNF, but upregulated IFN-γ in BeWo cells. For explants, LPS induced high levels of IL-10, TGF-ß1 and IFN-γ. Finally, it was observed that the inhibition of TRIF and NF-κB increased parasitism and modulated TGF-ß1 in BeWo cells, while the inhibition of MyD88 and NF-κB increased T. gondii infection and modulated IFN-γ in explants. It can be concluded that the TLR4 pathway is important for the control of T. gondii replication in BeWo cells and villous explants, in a dependent-manner of TRIF, MyD88, NF-κB and cytokines.

Cyclooxygenase (COX)-2 modulates Toxoplasma gondii infection, immune response and lipid droplets formation in human trophoblast cells and villous explants.

Congenital toxoplasmosis is represented by the transplacental passage of Toxoplasma gondii from the mother to the fetus. Our studies demonstrated that T. gondii developed mechanisms to evade of the host immune response, such as cyclooxygenase (COX)-2 and prostaglandin E2 (PGE2) induction, and these mediators can be produced/stored in lipid droplets (LDs). The aim of this study was to evaluate the role of COX-2 and LDs during T. gondii infection in human trophoblast cells and villous explants. Our data demonstrated that COX-2 inhibitors decreased T. gondii replication in trophoblast cells and villous. In BeWo cells, the COX-2 inhibitors induced an increase of pro-inflammatory cytokines (IL-6 and MIF), and a decrease in anti-inflammatory cytokines (IL-4 and IL-10). In HTR-8/SVneo cells, the COX-2 inhibitors induced an increase of IL-6 and nitrite and decreased IL-4 and TGF-ß1. In villous explants, the COX-2 inhibitors increased MIF and decreased TNF-α and IL-10. Furthermore, T. gondii induced an increase in LDs in BeWo and HTR-8/SVneo, but COX-2 inhibitors reduced LDs in both cells type. We highlighted that COX-2 is a key factor to T. gondii proliferation in human trophoblast cells, since its inhibition induced a pro-inflammatory response capable of controlling parasitism and leading to a decrease in the availability of LDs, which are essentials for parasite growth.

Heme Oxygenase-1 Induction in Human BeWo Trophoblast Cells Decreases Toxoplasma gondii Proliferation in Association With the Upregulation of p38 MAPK Phosphorylation and IL-6 Production.

Heme oxygenase-1 (HO-1) enzyme exerts beneficial effects at the maternal-fetal interface, especially in trophoblasts, being involved in survival and maturation of these cell phenotypes. Trophoblast cells play essential roles throughout pregnancy, being the gateway for pathogens vertically transmitted, such as Toxoplasma gondii. It was previously shown that HO-1 activity was involved in the control of T. gondii infection in vivo; however, its contribution in trophoblast cells during T. gondii infection, remain undefined. Thus, this study aimed to investigate the influence of HO-1 in T. gondii-infected BeWo and HTR-8/SVneo human trophoblast cells. For this purpose, trophoblast cells were infected and the HO-1 expression was evaluated. T. gondii-infected BeWo cells were treated with hemin or CoPPIX, as inducers of HO-1, or with bilirubin, an end-product of HO-1, and the parasitism was quantified. The involvement of p38 MAPK, a regulator of HO-1, and the cytokine production, were also evaluated. It was found that T. gondii decreased the HO-1 expression in BeWo but not in HTR-8/SVneo cells. When treated with the HO-1 inducers or bilirubin, BeWo cells reduced the parasite proliferation. T. gondii also decreased the p38 MAPK phosphorylation in BeWo cells; on the other hand, HO-1 induction sustained its activation. Finally, the IL-6 production was upregulated by HO-1 induction in T. gondii-infected cells, which was associated with the control of infection.

Macrophage migration inhibitory factor (MIF) and pregnancy may impact the balance of intestinal cytokines and the development of intestinal pathology caused by Toxoplasma gondii infection.

Toxoplasma gondii (T. gondii) is an intracellular parasite responsible for causing toxoplasmosis. When infection occurs during pregnancy, it can produce severe congenital infection with ocular and neurologic damage to the infant. From the oral infection parasite reaches the intestine, causing inflammatory response, damage in tissue architecture and systemic dissemination. Macrophage migration inhibition factor (MIF) is a cytokine secreted from both immune and non-immune cells, including gut epithelial cells. MIF is described to promote inflammatory responses, to be associated in colitis pathogenesis and also to play role in maintaining the intestinal barrier. The aim of the present study was to evaluate the influence of the pregnancy and MIF deficiency on T. gondii infection in the intestinal microenvironment and to address how these factors can impact on the intestinal architecture and local cytokine profile. For this purpose, small intestine of pregnant and non-pregnant C57BL/6 MIF deficient mice (MIF-/-) and Wild-type (WT) orally infected with 5 cysts of ME-49 strain of T. gondii were collected on day 8th of infection. Intestines were processed for morphological and morphometric analyses, parasite quantification and for cytokines mensuration. Our results showed that the absence of MIF and pregnancy caused an increase in T. gondii infection index. T. gondii immunolocalization demonstrated that segments preferentially infected with T. gondii were duodenum and ileum. The infection caused a reduction in the size of the intestinal villi, whereas, infection associated with pregnancy caused an increase in villi size due to edema caused by the infection. Also, the goblet cell number was increased in the ileum of MIF-/- mice, when compared to the corresponding WT group. Analyses of cytokine production in the small intestine showed that MIF was up regulated in the gut of pregnant WT mice due to infection. Also, infection provoked an intense Th1 response that was more exacerbated in pregnant MIF-/- mice. We also detected that the Th2/Treg response was more pronounced in MIF-/- mice. Altogether, our results demonstrated that pregnancy and MIF deficiency interferes in the balance of the intestinal cytokines and favors a Th1-immflamatory profile, which in turn, impact in the development of pathology caused by T. gondii infection in the intestinal microenvironment.

Erratum to "Macrophage migration inhibitory factor (MIF) and pregnancy may impact the balance of intestinal cytokines and the development of intestinal pathology caused by Toxoplasma gondii infection" [Cytokine: X 2 (2020) 100034].

[This corrects the article DOI: 10.1016/j.cytox.2020.100034.].

Biogenic Silver Nanoparticles Can Control Toxoplasma gondii Infection in Both Human Trophoblast Cells and Villous Explants.

The combination of sulfadiazine and pyrimethamine plus folinic acid is the conventional treatment for congenital toxoplasmosis. However, this classical treatment presents teratogenic effects and bone marrow suppression. In this sense, new therapeutic strategies are necessary to reduce these effects and improve the control of infection. In this context, biogenic silver nanoparticles (AgNp-Bio) appear as a promising alternative since they have antimicrobial, antiviral, and antiparasitic activity. The purpose of this study to investigate the action of AgNp-Bio in BeWo cells, HTR-8/SVneo cells and villous explants and its effects against Toxoplasma gondii infection. Both cells and villous explants were treated with different concentrations of AgNp-Bio or combination of sulfadiazine + pyrimethamine (SDZ + PYZ) in order to verify the viability. After, cells and villi were infected and treated with AgNp-Bio or SDZ + PYZ in different concentrations to ascertain the parasite proliferation and cytokine production profile. AgNp-Bio treatment did not reduce the cell viability and villous explants. Significant reduction was observed in parasite replication in both cells and villous explants treated with silver nanoparticles and classical treatment. The AgNp-Bio treatment increased of IL-4 and IL-10 by BeWo cells, while HTR8/SVneo cells produced macrophage migration inhibitory factor (MIF) and IL-4. In the presence of T. gondii, the treatment induced high levels of MIF production by BeWo cells and IL-6 by HTR8SV/neo. In villous explants, the AgNp-Bio treatment downregulated production of IL-4, IL-6, and IL-8 after infection. In conclusion, AgNp-Bio can decrease T. gondii infection in trophoblast cells and villous explants. Therefore, this treatment demonstrated the ability to reduce the T. gondii proliferation with induction of inflammatory mediators in the cells and independent of mediators in chorionic villus which we consider the use of AgNp-Bio promising in the treatment of toxoplasmosis in BeWo and HTR8/SVneo cell models and in chorionic villi.

Experimental models of maternal-fetal interface and their potential use for nanotechnology applications.

During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal-fetal interaction and the action of NPs in the placental environment.

Increased Toxoplasma gondii Intracellular Proliferation in Human Extravillous Trophoblast Cells (HTR8/SVneo Line) Is Sequentially Triggered by MIF, ERK1/2, and COX-2.

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine, which mediates the regulation of diverse cellular functions. It is produced by extravillous trophoblastic cells and has been found to be involved in the pathogenesis of diseases caused by some protozoa, including Toxoplasma gondii. Previous studies demonstrated the ability of T. gondii to take advantage of MIF action in human trophoblast cells. However, MIF action in T. gondii-infected extravillous trophoblastic cells (HTR8/SVneo cell line) has not been fully investigated. The present study aimed to investigate the role of MIF in T. gondii-infected HTR8/SVneo cells and verify the intracellular signaling pathways triggered by this cytokine. We found that T. gondii increased MIF production by HTR8/SVneo cells, and by contrast, MIF inhibition, by ISO-1, led to a significant decrease in T. gondii proliferation and CD74 expression in HTR8/SVneo cells. Moreover, in infected HTR8/SVneo cells, the addition of recombinant MIF (rMIF) increased CD44 co-receptor expression, ERK1/2 phosphorylation, COX-2 expression, and IL-8 production, which favored T. gondii proliferation. Our findings indicate that T. gondii can use MIF to modulate important factors in HTR8/SVneo cells, being a possible explanation for the higher susceptibility of extravillous trophoblast cells than other trophoblast cell populations.

Cyclooxygenase (COX)-2 Inhibitors Reduce Toxoplasma gondii Infection and Upregulate the Pro-inflammatory Immune Response in Calomys callosus Rodents and Human Monocyte Cell Line.

Toxoplasma gondii is able to infect a wide range of vertebrates, including humans. Studies show that cyclooxygenase-2 (COX-2) is a modulator of immune response in multiple types of infection, such as Trypanosoma cruzi. However, the role of COX-2 during T. gondii infection is still unclear. The aim of this study was to investigate the role of COX-2 during infection by moderately or highly virulent strains of T. gondii in Calomys callosus rodents and human THP-1 cells. C. callosus were infected with 50 cysts of T. gondii (ME49), treated with COX-2 inhibitors (meloxicam or celecoxib) and evaluated to check body weight and morbidity. After 40 days, brain and serum were collected for detection of T. gondii by real-time PCR and immunohistochemistry or cytokines by CBA. Furthermore, peritoneal macrophages or THP-1 cells, infected with RH strain or uninfected, were treated with meloxicam or celecoxib to evaluate the parasite proliferation by colorimetric assay and cytokine production by ELISA. Finally, in order to verify the role of prostaglandin E2 in COX-2 mechanism, THP-1 cells were infected, treated with meloxicam or celecoxib plus PGE2, and analyzed to parasite proliferation and cytokine production. The data showed that body weight and morbidity of the animals changed after infection by T. gondii, under both treatments. Immunohistochemistry and real-time PCR showed a reduction of T. gondii in brains of animals treated with both COX-2 inhibitors. Additionally, it was observed that both COX-2 inhibitors controlled the T. gondii proliferation in peritoneal macrophages and THP-1 cells, and the treatment with PGE2 restored the parasite growth in THP-1 cells blocked to COX-2. In the serum of Calomys, upregulation of pro-inflammatory cytokines was detected, while the supernatants of peritoneal macrophages and THP-1 cells demonstrated significant production of TNF and nitrite, or TNF, nitrite and MIF, respectively, under both COX-2 inhibitors. Finally, PGE2 treatment in THP-1 cells triggered downmodulation of pro-inflammatory mediators and upregulation of IL-8 and IL-10. Thus, COX-2 is an immune mediator involved in the susceptibility to T. gondii regardless of strain or cell types, since inhibition of this enzyme induced control of infection by upregulating important pro-inflammatory mediators against Toxoplasma.

Susceptibility of human villous (BeWo) and extravillous (HTR-8/SVneo) trophoblast cells to Toxoplasma gondii infection is modulated by intracellular iron availability.

Congenital toxoplasmosis is a serious health problem that can lead to miscarriage. HTR-8/SVneo is a first trimester extravillous trophoblast, while BeWo is a choriocarcinoma with properties of villous trophoblast cells. In the placenta, iron is taken up from Fe-transferrin through the transferrin receptor being the ion an important nutrient during pregnancy and also for Toxoplasma gondii proliferation. The aim of this study was to evaluate the role of iron in T. gondii proliferation in BeWo and HTR-8/SVneo cells and in human chorionic villous explants. The cells were infected with T. gondii, iron supplemented or deprived by holo-transferrin or deferoxamine, respectively, and parasite proliferation and genes related to iron balance were analyzed. It was verified that the addition of holo-transferrin increased, and DFO decreased the parasite multiplication in both trophoblastic cells, however, in a more expressive manner in HTR-8/SVneo, indicating that the parasite depends on iron storage in trophoblastic cells for its growth. Also, tachyzoites pretread with DFO proliferate normally in trophoblastic cells demonstrating that DFO itself does not interfere with parasite proliferation. Additionally, T. gondii infection induced enhancement in transferrin receptor mRNA expression levels in trophoblastic cells, and the expression was higher in HTR-8/SVneo compared with BeWo. Finally, DFO-treatment was able to reduce the parasite replication in villous explants. Thus, the iron supplementation can be a double-edged sword; in one hand, it could improve the supplement of an essential ion to embryo/fetus development, and on the other hand, could improve the parasite proliferation enhancing the risk of congenital infection.