26 research outputs found
Role of the Macrophage Migration Inhibitory Factor (MIF) in the survival of first trimester human placenta under induced stress conditions
Macrophage Migration Inhibitory Factor (MIF) is a multifunctional molecule highly secreted by human placenta mainly in the early phases of pregnancy. Studies in different cells show that MIF is a pro-survival factor by binding to its receptor CD74. By using the in vitro model of placental explants from first trimester pregnancy, we investigated the role of MIF in the survival of placental cells under induced stress conditions that promote apoptosis or mimic the hypoxia/re-oxygenation (H/R) injury that placenta could suffer in vivo. We demonstrated that recombinant MIF (rMIF) treatment was able to reduce caspase-3 activation when cultures were challenged with the apoptosis-inducer Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) while, in the cultures exposed to H/R, the treatment with rMIF did not show any effect. However, a significant increase in caspase-3 and caspase-8 activation was found when H/R-exposed cultures, were treated with anti-MIF or anti-CD74 antibody. We also observed that under H/R, a significant amount of endogenous MIF was released into the medium, which could account for the lack of effect of rMIF added to the cultures. Our results demonstrate for the first time that the MIF/CD74 axis contributes to maintain trophoblast homeostasis, by preventing abnormal apoptotic death
Rottlerin-mediated inhibition of Toxoplasma gondii growth in BeWo trophoblast-like cells
Autophagy is a crucial and physiological process for cell survival from yeast to mammals, including protozoan parasites. Toxoplasma gondii, an intracellular parasite, typically exploits autophagic machinery of host cell; however host cell upregulates autophagy to combat the infection. Herein we tested the efficacy of Rottlerin, a natural polyphenol with autophagic promoting properties, against Toxoplasma infection on the chorioncarcinoma-derived cell line BeWo. We found that Rottlerin, at sub-toxic doses, induced morphological and biochemical alterations associated with autophagy and decreased Toxoplasma growth in infected cells. Although autophagy was synergically promoted by Toxoplasma infection in combination with Rottlerin treatment, the use of the autophagy inhibitor chloroquine revealed that Rottlerin anti-parasitic effect was largely autophagy-independent and likely mediated by the converging inhibitory effect of Rottlerin and Toxoplasma in host protein translation, mediated by mTOR inhibition and eIF2α phosphorylation. Both events, which on one hand could explain the additive effect on autophagy induction, on the other hand led to inhibition of protein synthesis, thereby depriving Toxoplasma of metabolically essential components for multiplication. We suggest that modulation of the competition between pathogen requirement and host cell defense might be an attractive, novel therapeutic approach against Toxoplasma infection and encourage the development of Rottlerin-based new therapeutic formulations
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
Acquired and Congenital Ocular Toxoplasmosis Experimentally Induced in Calomys callosus (Rodentia, Cricetidae)
An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimmune uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant- and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40% of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75% of the females and 50% of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as additional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitute in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection
Acquired and Congenital Ocular Toxoplasmosis Experimentally Induced in Calomys callosus (Rodentia, Cricetidae)
An experimental model for acquired and congenital ocular toxoplasmosis
as well as a model to induce experimental autoimmune uveitis (EAU) was
investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was
used to infect males and pregnant- and not pregnant-females while
S-antigen, a major glycoprotein of the retinal photoreceptor cell, was
used to induce EAU. The ocular lesions elicited by T. gondii were
characterized by the presence of cysts, free tachyzoites and
inflammatory cells in the retina or related tissues. In the congenital
form, 40% of the fetus presented ocular lesions, i.e., presence of
cysts in the retina, vitreous, and extra-retinal tissues. In the
acquired form, 75% of the females and 50% of the males presented
unilateral ocular cysts both at 21 and 47 days post-infection. It was
also demonstrated that S-antigen was not uveitogenic in the C. callosus
model. No lesion was observed in the animals exclusively immunized with
this retinal component, even when jacalin was used as additional
adjuvant for polyclonal response to the retinal antigen. It can be
concluded that C. callosus may constitute in a promising model for
study both acquired and congenital ocular toxoplasmosis, particularly
when it is important to make sure that a non autoimmune process is
involved in the genesis of the ocular infection
Experimental infection of Calomys callosus (Rodentia, Cricetidae) by Toxoplasma gondii
Calomys callosus, Rengger 1830 (Rodentia, Cricetidae), a wild rodent
found in Central Brazil, was studied to investigate its susceptibility
to Toxoplasma gondii experimental infection and its humoral immune
response against this protozoa. The electrophoretic profile of the
serum proteins of C. callosus showed that IgG, which shows no affinity
to Protein A, has higher cross reactivity with rat IgG than with IgG
from other rodents. The susceptibility assay was performed by
inoculation groups of animals with various suspensions of T. gondii
tachyzoites from 10^2 to 10^6 parasites. All animals died between 3 and
9 days after infection and the kinetics of antibody synthesis was
determined. Basically, they recognized predominantly the immunodominant
antigen SAG-1 (P30). The immunohistochemistry assays revealed that the
liver was the most heavily infected organ, followed by the spleen,
lungs, intestine, brain and kidneys. It can be concluded that C.
callosus is an excellent experimental model for acute phase of
Toxoplasma infection
Experimental infection of Calomys callosus (Rodentia, Cricetidae) by Toxoplasma gondii
Calomys callosus, Rengger 1830 (Rodentia, Cricetidae), a wild rodent
found in Central Brazil, was studied to investigate its susceptibility
to Toxoplasma gondii experimental infection and its humoral immune
response against this protozoa. The electrophoretic profile of the
serum proteins of C. callosus showed that IgG, which shows no affinity
to Protein A, has higher cross reactivity with rat IgG than with IgG
from other rodents. The susceptibility assay was performed by
inoculation groups of animals with various suspensions of T. gondii
tachyzoites from 10^2 to 10^6 parasites. All animals died between 3 and
9 days after infection and the kinetics of antibody synthesis was
determined. Basically, they recognized predominantly the immunodominant
antigen SAG-1 (P30). The immunohistochemistry assays revealed that the
liver was the most heavily infected organ, followed by the spleen,
lungs, intestine, brain and kidneys. It can be concluded that C.
callosus is an excellent experimental model for acute phase of
Toxoplasma infection
Experimental infection of Calomys callosus (Rodentia, Cricetidae) by Toxoplasma gondii
Calomys callosus, Rengger 1830 (Rodentia, Cricetidae), a wild rodent
found in Central Brazil, was studied to investigate its susceptibility
to Toxoplasma gondii experimental infection and its humoral immune
response against this protozoa. The electrophoretic profile of the
serum proteins of C. callosus showed that IgG, which shows no affinity
to Protein A, has higher cross reactivity with rat IgG than with IgG
from other rodents. The susceptibility assay was performed by
inoculation groups of animals with various suspensions of T. gondii
tachyzoites from 10^2 to 10^6 parasites. All animals died between 3 and
9 days after infection and the kinetics of antibody synthesis was
determined. Basically, they recognized predominantly the immunodominant
antigen SAG-1 (P30). The immunohistochemistry assays revealed that the
liver was the most heavily infected organ, followed by the spleen,
lungs, intestine, brain and kidneys. It can be concluded that C.
callosus is an excellent experimental model for acute phase of
Toxoplasma infection
Experimental infection of Calomys callosus (Rodentia, Cricetidae) by Toxoplasma gondii
Calomys callosus, Rengger 1830 (Rodentia, Cricetidae), a wild rodent
found in Central Brazil, was studied to investigate its susceptibility
to Toxoplasma gondii experimental infection and its humoral immune
response against this protozoa. The electrophoretic profile of the
serum proteins of C. callosus showed that IgG, which shows no affinity
to Protein A, has higher cross reactivity with rat IgG than with IgG
from other rodents. The susceptibility assay was performed by
inoculation groups of animals with various suspensions of T. gondii
tachyzoites from 10^2 to 10^6 parasites. All animals died between 3 and
9 days after infection and the kinetics of antibody synthesis was
determined. Basically, they recognized predominantly the immunodominant
antigen SAG-1 (P30). The immunohistochemistry assays revealed that the
liver was the most heavily infected organ, followed by the spleen,
lungs, intestine, brain and kidneys. It can be concluded that C.
callosus is an excellent experimental model for acute phase of
Toxoplasma infection