scholarly journals Dehydroepiandrosterone Effect on Toxoplasma gondii: Molecular Mechanisms Associated to Parasite Death

2021 ◽  
Vol 9 (3) ◽  
pp. 513
Author(s):  
Saé Muñiz-Hernández ◽  
Angélica Luna-Nophal ◽  
Carmen T. Gómez-De León ◽  
Lenin Domínguez-Ramírez ◽  
Olga A. Patrón-Soberano ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Molecular Mechanisms ◽  
Cytochrome B5 ◽  
Protozoan Parasite ◽  
Intracellular Parasites ◽  
Sds Page ◽  
Parasitic Load ◽  
Dhea Treatment

Toxoplasmosis is a zoonotic disease caused by the apicomplexa protozoan parasite Toxoplasma gondii. This disease is a health burden, mainly in pregnant women and immunocompromised individuals. Dehydroepiandrosterone (DHEA) has proved to be an important molecule that could drive resistance against a variety of infections, including intracellular parasites such as Plasmodium falciparum and Trypanozoma cruzi, among others. However, to date, the role of DHEA on T. gondii has not been explored. Here, we demonstrated for the first time the toxoplasmicidal effect of DHEA on extracellular tachyzoites. Ultrastructural analysis of treated parasites showed that DHEA alters the cytoskeleton structures, leading to the loss of the organelle structure and organization as well as the loss of the cellular shape. In vitro treatment with DHEA reduces the viability of extracellular tachyzoites and the passive invasion process. Two-dimensional (2D) SDS-PAGE analysis revealed that in the presence of the hormone, a progesterone receptor membrane component (PGRMC) with a cytochrome b5 family heme/steroid binding domain-containing protein was expressed, while the expression of proteins that are essential for motility and virulence was highly reduced. Finally, in vivo DHEA treatment induced a reduction of parasitic load in male, but not in female mice.

scholarly journals Dehydroepiandrosterone Effect on Toxoplasma gondii: Molecular Mechanisms Associated to Parasite Death

2021 ◽  
Author(s):  
Jorge Morales-Montor
Keyword(s):  
Toxoplasma Gondii ◽  
Molecular Mechanisms ◽  
Cytochrome B5 ◽  
Protozoan Parasite ◽  
Intracellular Parasites ◽  
Sds Page ◽  
Parasitic Load ◽  
Dhea Treatment

Toxoplasmosis is a zoonotic disease caused by the apicomplexa protozoan parasite Toxoplasma gondii. This disease is a health burden, mainly in pregnant women and immunocompromised individuals. Dehydroepiandrosterone (DHEA) has proved to be an important molecule that could drive resistance against a variety of infections, including intracellular parasites such as Plasmodium falciparum and Trypanozoma cruzi, among others. However, to date it has not been explored the role of DHEA on T. gondii. In here, we demonstrated for the first time the toxoplasmicidal effect of DHEA on extracellular tachyzoites. Ultrastructural analysis of treated parasites showed that DHEA alters the cytoskeleton structures, leading to the loss of the organelle structure and organization, as well as the loss of the cellular shape. In vitro treatment with DHEA reduces the viability of extracellular tachyzoites and passive invasion process. 2D SDS-PAGE analysis revealed that in the presence of the hormone a progesterone receptor membrane component (PGRMC) with a cytochrome b5 family heme/steroid binding domain-containing protein was expressed, while the expression of proteins that are essential for motility and virulence was highly reduced. Finally, in vivo DHEA treatment induced a reduction of parasitic load in male, but not in female mice.

scholarly journals The ketolide antibiotics HMR 3647 and HMR 3004 are active against Toxoplasma gondii in vitro and in murine models of infection.

1997 ◽  
Vol 41 (10) ◽  
pp. 2137-2140 ◽  
Author(s):  
F G Araujo ◽  
A A Khan ◽  
T L Slifer ◽  
A Bryskier ◽  
J S Remington
Keyword(s):  
Toxoplasma Gondii ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Resistant Bacteria ◽  
New Class ◽  
Human Foreskin Fibroblasts ◽  
Significant Toxicity ◽  
Different Strains

Ketolides are a new class of macrolide antibiotics that have been shown to be active against a variety of bacteria including macrolide-resistant bacteria and mycobacteria. We examined two ketolides, HMR 3647 and HMR 3004, for their in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. In vitro, both ketolides at concentrations as low as 0.05 microg/ml markedly inhibited replication of tachyzoites of the RH strain within human foreskin fibroblasts. HMR 3004 demonstrated some toxicity for host cells after they were exposed to 5 microg of the drug per ml for 72 h. In contrast, HMR 3647 did not show any significant toxicity even at concentrations as high as 25 microg/ml. In vivo, both ketolides provided remarkable protection against death in mice lethally infected intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain of T. gondii. A dosage of 100 mg of HMR 3647 per kg of body weight per day administered for 10 days protected 50% of mice infected with tachyzoites. The same dosage of HMR 3004 protected 100% of the mice. In mice infected with cysts, a dosage of 30 mg of HMR 3647 per kg per day protected 100% of the mice, whereas a dosage of 40 mg of HMR 3004 per kg per day protected 75% of the mice. These results demonstrate that HMR 3647 and HMR 3004 possess excellent activities against two different strains of T. gondii and may be useful for the treatment of toxoplasmosis in humans.

scholarly journals Hydroxylamine and Carboxymethoxylamine Can Inhibit Toxoplasma gondii Growth through an Aspartate Aminotransferase-Independent Pathway

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Jixu Li ◽  
Huanping Guo ◽  
Eloiza May Galon ◽  
Yang Gao ◽  
Seung-Hun Lee ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Drug Targets ◽  
Protozoan Parasite ◽  
Cell Types ◽  
Lytic Cycle ◽  
Type I ◽  
Content Type ◽  
Mechanism Of Inhibition

ABSTRACT Toxoplasma gondii is an obligate intracellular protozoan parasite and a successful parasitic pathogen in diverse organisms and host cell types. Hydroxylamine (HYD) and carboxymethoxylamine (CAR) have been reported as inhibitors of aspartate aminotransferases (AATs) and interfere with the proliferation in Plasmodium falciparum. Therefore, AATs are suggested as drug targets against Plasmodium. The T. gondii genome encodes only one predicted AAT in both T. gondii type I strain RH and type II strain PLK. However, the effects of HYD and CAR, as well as their relationship with AAT, on T. gondii remain unclear. In this study, we found that HYD and CAR impaired the lytic cycle of T. gondii in vitro, including the inhibition of invasion or reinvasion, intracellular replication, and egress. Importantly, HYD and CAR could control acute toxoplasmosis in vivo. Further studies showed that HYD and CAR could inhibit the transamination activity of rTgAAT in vitro. However, our results confirmed that deficiency of AAT in both RH and PLK did not reduce the virulence in mice, although the growth ability of the parasites was affected in vitro. HYD and CAR could still inhibit the growth of AAT-deficient parasites. These findings indicated that HYD and CAR inhibition of T. gondii growth and control of toxoplasmosis can occur in an AAT-independent pathway. Overall, further studies focusing on the elucidation of the mechanism of inhibition are warranted. Our study hints at new substrates of HYD and CAR as potential drug targets to inhibit T. gondii growth.

scholarly journals The C-terminus of cytochrome b5 confers endoplasmic reticulum specificity by preventing spontaneous insertion into membranes

2007 ◽  
Vol 401 (3) ◽  
pp. 701-709 ◽  
Author(s):  
Matthew P. A. Henderson ◽  
Yeen Ting Hwang ◽  
John M. Dyer ◽  
Robert T. Mullen ◽  
David W. Andrews
Keyword(s):  
Endoplasmic Reticulum ◽  
Subcellular Localization ◽  
Lipid Bilayers ◽  
Fusion Proteins ◽  
Molecular Mechanisms ◽  
Cytochrome B5 ◽  
Terminal Sequence ◽  
C Terminus

The molecular mechanisms that determine the correct subcellular localization of proteins targeted to membranes by tail-anchor sequences are poorly defined. Previously, we showed that two isoforms of the tung oil tree [Vernicia (Aleurites) fordii] tail-anchored Cb5 (cytochrome b5) target specifically to ER (endoplasmic reticulum) membranes both in vivo and in vitro [Hwang, Pelitire, Henderson, Andrews, Dyer and Mullen (2004) Plant Cell 16, 3002–3019]. In the present study, we examine the targeting of various tung Cb5 fusion proteins and truncation mutants to purified intracellular membranes in vitro in order to assess the importance of the charged CTS (C-terminal sequence) in targeting to specific membranes. Removal of the CTS from tung Cb5 proteins resulted in efficient binding to both ER and mitochondria. Results from organelle competition, liposome-binding and membrane proteolysis experiments demonstrated that removal of the CTS results in spontaneous insertion of tung Cb5 proteins into lipid bilayers. Our results indicate that the CTSs from plant Cb5 proteins provide ER specificity by preventing spontaneous insertion into incorrect subcellular membranes.

scholarly journals New Method for the Orthogonal Labeling and Purification of Toxoplasma gondii Proteins While Inside the Host Cell

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Gregory M. Wier ◽  
Erica M. McGreevy ◽  
Mark J. Brown ◽  
Jon P. Boyle
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Click Reaction ◽  
Severe Disease ◽  
Protozoan Parasite ◽  
Trna Synthetase ◽  
Content Type ◽  
Fluorescent Tags

ABSTRACTToxoplasma gondiiis an obligate intracellular protozoan parasite that is capable of causing severe disease in immunocompromised humans. How T. gondii is able to modulate the host cell to support itself is still poorly understood. Knowledge pertaining to the host-parasite interaction could be bolstered by developing a system to specifically label parasite proteins while the parasite grows inside the host cell. For this purpose, we have created a strain of T. gondii that expresses a mutant Escherichia coli methionyl-tRNA synthetase (MetRSNLL) that allows methionine tRNA to be loaded with the azide-containing methionine analog azidonorleucine (Anl). Anl-containing proteins are susceptible to a copper-catalyzed “click” reaction to attach affinity tags for purification or fluorescent tags for visualization. The MetRSNLL-Anl system labels nascent T. gondii proteins in an orthogonal fashion, labeling proteins only in MetRSNLL-expressing parasites. This system should be useful for nonradioactive pulse-chase studies and purification of nascently translated proteins. Although this approach allows labeling of a diverse array of parasite proteins, secreted parasite proteins appear to be only minimally labeled in MetRSNLL-expressing T. gondii. The minimal labeling of secreted proteins is likely a consequence of the selective charging of the initiator tRNA (and not the elongator methionine tRNA) by the heterologously expressed bacterial MetRS.IMPORTANCEStudying how T. gondii modifies the host cell to permit its survival is complicated by the complex protein environment of the host cell. The approach presented in this article provides the first method for specific labeling of T. gondii proteins while the parasite grows inside the host cell. We show that this approach is useful for pulse-chase labeling of parasite proteins duringin vitrogrowth. It should also be applicable duringin vivoinfections and in other apicomplexan parasites, including Plasmodium spp.

scholarly journals Rifapentine is active in vitro and in vivo against Toxoplasma gondii.

1996 ◽  
Vol 40 (6) ◽  
pp. 1335-1337 ◽  
Author(s):  
F G Araujo ◽  
A A Khan ◽  
J S Remington
Keyword(s):  
Toxoplasma Gondii ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Intracellular Replication ◽  
Degree Of Protection

Rifapentine, a derivative of rifamycin, was examined for its in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. The drug inhibited the intracellular replication of parasites and was not cytotoxic for the host cells at inhibitory concentrations. Mice infected either intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain were protected against death by treatment with rifapentine. The degree of protection was similar to that induced by atovaquone and apparently higher than that induced by rifabutin. Rifapentine may be a useful drug for the treatment of toxoplasmosis in immunocompromised individuals.

scholarly journals The Structural and Molecular Underpinnings of Gametogenesis in Toxoplasma gondii

2020 ◽  
Vol 10 ◽  
Author(s):  
Ramiro Tomasina ◽  
María E. Francia
Keyword(s):  
Toxoplasma Gondii ◽  
Reproductive Potential ◽  
Protozoan Parasite ◽  
Life Forms ◽  
Farm Animals ◽  
Genetic Admixture ◽  
Intermediate Hosts ◽  
Male Gametes

Toxoplasma gondii is a widely prevalent protozoan parasite member of the phylum Apicomplexa. It causes disease in humans with clinical outcomes ranging from an asymptomatic manifestation to eye disease to reproductive failure and neurological symptoms. In farm animals, and particularly in sheep, toxoplasmosis costs the industry millions by profoundly affecting their reproductive potential. As do all the parasites in the phylum, T. gondii parasites go through sexual and asexual replication in the context of an heteroxenic life cycle involving members of the Felidae family and any warm-blooded vertebrate as definitive and intermediate hosts, respectively. During sexual replication, merozoites differentiate into female and male gametes; their combination gives rise to a zygotes which evolve into sporozoites that encyst and are shed in cat’s feces as environmentally resistant oocysts. During zygote formation T. gondii parasites are diploid providing the parasite with a window of opportunity for genetic admixture making this a key step in the generation of genetic diversity. In addition, oocyst formation and shedding are central to dissemination and environmental contamination with infectious parasite forms. In this minireview we summarize the current state of the art on the process of gametogenesis. We discuss the unique structures of macro and microgametes, an insight acquired through classical techniques, as well as the more recently attained molecular understanding of the routes leading up to these life forms by in vitro and in vivo systems. We pose a number of unanswered questions and discuss these in the context of the latest findings on molecular cues mediating stage switching, and the implication for the field of newly available in vitro tools.

scholarly journals IFN-γ stimulated murine and human neurons mount anti-parasitic defenses against the intracellular parasite Toxoplasma gondii

2021 ◽  
Author(s):  
Sambamurthy Chandrasekaran ◽  
Joshua A Kochanowsky ◽  
Emily F Merritt ◽  
Anita A Koshy
Keyword(s):  
Toxoplasma Gondii ◽  
Defense Mechanisms ◽  
Neuronal Cultures ◽  
Wild Type ◽  
Intracellular Parasites ◽  
Human Neurons ◽  
Transgenic Parasites ◽  
Ifn Γ

Dogma holds that Toxoplasma gondii persists in neurons because neurons cannot clear intracellular parasites, even with IFN-γ stimulation. As several recent studies questioned this idea, we used primary murine neuronal cultures from wild-type and transgenic mice in combination with IFN-γ stimulation and parental and transgenic parasites to reassess IFN-γ dependent neuronal clearance of intracellular parasites. We found that neurons respond to IFN-γ and that a subset of neurons clear intracellular parasites via immunity regulated GTPases. Whole neuron reconstructions from mice infected with parasites that trigger neuron GFP expression only after full invasion revealed that ~40% of these T. gondii-invaded neurons no longer harbor parasites. Finally, IFN-γ stimulated human stem cell derived neurons showed a ~ 50% decrease in parasite infection rate when compared to unstimulated cultures. This work highlights the capability of human and murine neurons to mount cytokine-dependent anti-T. gondii defense mechanisms in vitro and in vivo.

scholarly journals In Vitro and In Vivo Activity of Anogeissus leiocarpa Bark Extract and Isolated Metabolites against Toxoplasma gondii

Planta Medica ◽  
2020 ◽  
Vol 86 (04) ◽  
pp. 294-302 ◽  
Author(s):  
Jérémy Spalenka ◽  
Jane Hubert ◽  
Laurence Voutquenne-Nazabadioko ◽  
Sandie Escotte-Binet ◽  
Nicolas Borie ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Ethanol Extract ◽  
Protozoan Parasite ◽  
Biological Data ◽  
Bark Extract ◽  
Significant Activity ◽  
Centrifugal Partition Chromatography ◽  
Pure Compounds

Abstract Toxoplasma gondii, belonging to the Apicomplexa phylum, is a cosmopolitan protozoan parasite that affects at least 30% of the worldʼs population. In West Africa, the leaves and bark of the tree species Anogeissus leiocarpa (DC.) Guill. & Perr. are used against zoonosis in traditional medicine and play a key role in controlling diseases induced by Apicomplexans such as malaria. In this study, extracts, fractions, and pure compounds obtained from an ethanol extract of the bark of A. leiocarpa were evaluated against T. gondii infection in vitro and in vivo. The crude bark extract showed significant activity on tachyzoites from the T. gondii RH strain (IC50 = 59.30 µg/mL). The crude bark extract without tannins and pure trachelosperogenin E purified by centrifugal partition chromatography showed the highest activity (IC50s = 12.83 and 26.63 µg/mL, respectively) with satisfying selectivity indexes of 9.61 and 9.75, respectively. The crude bark extract without tannins and pure trachelosperogenin E were able to significantly inhibit host cell invasion by the parasite in vitro, while the crude bark extract without tannins was able to increase mice survival in our murine model of chronic toxoplasmosis. These results provide new biological data for natural compounds that could enhance the current panoply of treatments against toxoplasmosis.

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