Resistance towards monensin is proposed to be acquired in a Toxoplasma gondii model by reduced invasion and egress activities, in addition to increased intracellular replication

Parasitology ◽  
2017 ◽  
Vol 145 (3) ◽  
pp. 313-325 ◽  
Author(s):  
AHMED THABET ◽  
JOHANNES SCHMIDT ◽  
SVEN BAUMANN ◽  
WALTHER HONSCHA ◽  
MARTIN VON BERGEN ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Toxoplasma Gondii ◽  
Metal Ion ◽  
Bioinformatic Analysis ◽  
Resistance Mechanisms ◽  
Host Cells ◽  
Intracellular Replication ◽  
Metal Ion Binding ◽  
Stable Isotope Labelling

SUMMARYMonensin (Mon) is an anticoccidial polyether ionophore widely used to control coccidiosis. The extensive use of polyether ionophores on poultry farms resulted in widespread resistance, but the underlying resistance mechanisms are unknown in detail. For analysing the mode of action by which resistance against polyether ionophores is obtained, we induced in vitro Mon resistance in Toxoplasma gondii-RH strain (MonR-RH) and compared it with the sensitive parental strain (Sen-RH). The proteome assessment of MonR-RH and Sen-RH strains was obtained after isotopic labelling using stable isotope labelling by amino acid in cell culture. Relative proteomic quantification between resistant and sensitive strains was performed using liquid chromatography-mass spectrometry/mass spectrometry. Overall, 1024 proteins were quantified and 52 proteins of them were regulated. The bioinformatic analysis revealed regulation of cytoskeletal and transmembrane proteins being involved in transport mechanisms, metal ion-binding and invasion. During invasion, actin and microneme protein 8 (MIC8) are seem to be important for conoid extrusion and forming moving junction with host cells, respectively. Actin was significantly upregulated, while MIC8 was downregulated, which indicate an invasion reduction in the resistant strain. Resistance against Mon is not a simple process but it involves reduced invasion and egress activity of T. gondii tachyzoites while intracellular replication is enhanced.

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 Trovafloxacin is active against Toxoplasma gondii.

1996 ◽  
Vol 40 (8) ◽  
pp. 1855-1859 ◽  
Author(s):  
A A Khan ◽  
T Slifer ◽  
F G Araujo ◽  
J S Remington
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cells ◽  
Intracellular Replication ◽  
Congenital Infections ◽  
Time To Death ◽  
Significant Toxicity ◽  
Acute Toxoplasmosis ◽  
Toxic Drugs

Drugs currently used for treatment of toxoplasmosis in pregnant women, congenital infections, immunocompromised patients, and patients with the ocular disease are not always effective or may be dangerous to use; therefore, there is a need for more-effective and less-toxic drugs. Recently, we examined a group of fluoroquinolones for in vitro and in vivo activities against Toxoplasma gondii. Among those examined in vitro (ciprofloxacin, fleroxacin, ofloxacin, temafloxacin, and trovafloxacin), only trovafloxacin significantly inhibited intracellular replication of T. gondii without significant toxicity for host cells. In a murine model of acute toxoplasmosis, 100 or 200 mg of trovafloxacin per kg of body weight per day for 10 days protected 100% of infected mice against death. A dose of 50 mg/kg/day protected 90% of the mice, and a dose of 25 mg/kg/day effected prolongation of time to death. The other fluoroquinolones did not have such in vivo activities. These results indicate that trovafloxacin may be useful for treatment of toxoplasmosis in humans.

scholarly journals 1,3,4-Thiadiazoles Effectively Inhibit Proliferation of Toxoplasma gondii

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1053
Author(s):  
Lidia Węglińska ◽  
Adrian Bekier ◽  
Katarzyna Dzitko ◽  
Barbara Pacholczyk-Sienicka ◽  
Łukasz Albrecht ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Cell Invasion ◽  
Direct Action ◽  
Human Fibroblasts ◽  
Imidazole Ring ◽  
Host Cells ◽  
In Vitro Assays ◽  
Host Cell Invasion

Congenital and acquired toxoplasmosis caused by the food- and water-born parasite Toxoplasma gondii (T. gondii) is one of the most prevalent zoonotic infection of global importance. T. gondii is an obligate intracellular parasite with limited capacity for extracellular survival, thus a successful, efficient and robust host cell invasion process is crucial for its survival, proliferation and transmission. In this study, we screened a series of novel 1,3,4-thiadiazole-2-halophenylamines functionalized at the C5 position with the imidazole ring (1b–12b) for their effects on T. gondii host cell invasion and proliferation. To achieve this goal, these compounds were initially subjected to in vitro assays to assess their cytotoxicity on human fibroblasts and then antiparasitic efficacy. Results showed that all of them compare favorably to control drugs sulfadiazine and trimethoprim in terms of T. gondii growth inhibition (IC50) and selectivity toward the parasite, expressed as selectivity index (SI). Subsequently, the most potent of them with meta-fluoro 2b, meta-chloro 5b, meta-bromo 8b, meta-iodo 11b and para-iodo 12b substitution were tested for their efficacy in inhibition of tachyzoites invasion and subsequent proliferation by direct action on established intracellular infection. All the compounds significantly inhibited the parasite invasion and intracellular proliferation via direct action on both tachyzoites and parasitophorous vacuoles formation. The most effective was para-iodo derivative 12b that caused reduction in the percentage of infected host cells by 44% and number of tachyzoites per vacuole by 93% compared to non-treated host cells. Collectively, these studies indicate that 1,3,4-thiadiazoles 1b–12b, especially 12b with IC50 of 4.70 µg/mL and SI of 20.89, could be considered as early hit compounds for future design and synthesis of anti-Toxoplasma agents that effectively and selectively block the invasion and subsequent proliferation of T. gondii into host cells.

scholarly journals Systematic Identification of Thiosemicarbazides for Inhibition of Toxoplasma gondii Growth In Vitro

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 614 ◽  
Author(s):  
Agata Paneth ◽  
Lidia Węglińska ◽  
Adrian Bekier ◽  
Edyta Stefaniszyn ◽  
Monika Wujec ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Small Molecules ◽  
High Selectivity ◽  
High Specificity ◽  
Host Cells ◽  
Structural Requirements ◽  
New Therapies ◽  
Cns Penetration ◽  
Systematic Identification

One of the key stages in the development of new therapies in the treatment of toxoplasmosis is the identification of new non-toxic small molecules with high specificity to Toxoplasma gondii. In the search for such structures, thiosemicarbazide-based compounds have emerged as a novel and promising leads. Here, a series of imidazole-thiosemicarbazides with suitable properties for CNS penetration was evaluated to determine the structural requirements needed for potent anti-Toxoplasma gondii activity. The best 4-arylthiosemicarbazides 3 and 4 showed much higher potency when compared to sulfadiazine at concentrations that are non-toxic to the host cells, indicating a high selectivity of their anti-toxoplasma activity.

scholarly journals ROP18-Mediated Transcriptional Reprogramming of HEK293T Cell Reveals New Roles of ROP18 in the Interplay Between Toxoplasma gondii and the Host Cell

2020 ◽  
Vol 10 ◽  
Author(s):  
Jie-Xi Li ◽  
Jun-Jun He ◽  
Hany M. Elsheikha ◽  
Jun Ma ◽  
Xiao-Pei Xu ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Hek293t Cell ◽  
Effector Proteins ◽  
Host Cells ◽  
Pathway Enrichment Analysis ◽  
Type I ◽  
Human Embryonic Kidney Cells ◽  
Pathway Enrichment

Toxoplasma gondii secretes a number of virulence-related effector proteins, such as the rhoptry protein 18 (ROP18). To further broaden our understanding of the molecular functions of ROP18, we examined the transcriptional response of human embryonic kidney cells (HEK293T) to ROP18 of type I T. gondii RH strain. Using RNA-sequencing, we compared the transcriptome of ROP18-expressing HEK293T cells to control HEK293T cells. Our analysis revealed that ROP18 altered the expression of 750 genes (467 upregulated genes and 283 downregulated genes) in HEK293T cells. Gene ontology (GO) and pathway enrichment analyses showed that differentially expressed genes (DEGs) were significantly enriched in extracellular matrix– and immune–related GO terms and pathways. KEGG pathway enrichment analysis revealed that DEGs were involved in several disease-related pathways, such as nervous system diseases and eye disease. ROP18 significantly increased the alternative splicing pattern “retained intron” and altered the expression of 144 transcription factors (TFs). These results provide new insight into how ROP18 may influence biological processes in the host cells via altering the expression of genes, TFs, and pathways. More in vitro and in vivo studies are required to substantiate these findings.

scholarly journals Novel Salmonella enterica Serovar Typhimurium Protein That Is Indispensable for Virulence and Intracellular Replication

2001 ◽  
Vol 69 (12) ◽  
pp. 7413-7418 ◽  
Author(s):  
Tahar van der Straaten ◽  
Angela van Diepen ◽  
Kitty Kwappenberg ◽  
Sjaak van Voorden ◽  
Kees Franken ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Function ◽  
Salmonella Enterica ◽  
Host Cells ◽  
Wild Type ◽  
Intracellular Replication ◽  
Oxygen Intermediates ◽  
Serovar Typhimurium

ABSTRACT Upon contact with host cells, the intracellular pathogenSalmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches. In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. This study reports the phenotypic and genotypic characterization of an S. enterica serovar Typhimurium mutant that is hypersusceptible to superoxide. The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribedSalmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonellachromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 104 to 107bacteria in C3H/HeN and 101 to 104 bacteria in BALB/c mice, the mutant strain was less virulent than the wild type. Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms. Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so. This phenotype could be restored to that of the wild type by sspJ complementation. The SspJ protein is found in the cytoplasmic membrane and periplasmic space. Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function. We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity.

Rv3351c, aMycobacterium tuberculosisgene that affects bacterial growth and alveolar epithelial cell viability

2015 ◽  
Vol 61 (12) ◽  
pp. 938-947 ◽  
Author(s):  
Rebecca L. Pavlicek ◽  
Kari Fine-Coulson ◽  
Tuhina Gupta ◽  
Frederick D. Quinn ◽  
James E. Posey ◽  
...  
Keyword(s):  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial Cells ◽  
Host Cells ◽  
Gene Products ◽  
Type Ii ◽  
Intracellular Replication ◽  
Cytotoxic Effects ◽  
Alveolar Epithelial ◽  
Type Ii Pneumocyte

Despite the interactions known to occur between various lower respiratory tract pathogens and alveolar epithelial cells (AECs), few reports examine factors influencing the interplay between Mycobacterium tuberculosis bacilli and AECs during infection. Importantly, in vitro studies have demonstrated that the M. tuberculosis hbha and esxA gene products HBHA and ESAT6 directly or indirectly influence AEC survival. In this report, we identify Rv3351c as another M. tuberculosis gene that impacts the fate of both the pathogen and AEC host. Intracellular replication of an Rv3351c mutant in the human AEC type II pneumocyte cell line A549 was markedly reduced relative to the complemented mutant and parent strain. Deletion of Rv3351c diminished the release of lactate dehydrogenase and decreased uptake of trypan blue vital stain by host cells infected with M. tuberculosis bacilli, suggesting attenuated cytotoxic effects. Interestingly, an isogenic hbha mutant displayed reductions in AEC killing similar to those observed for the Rv3351c mutant. This opens the possibility that multiple M. tuberculosis gene products interact with AECs. We also observed that Rv3351c aids intracellular replication and survival of M. tuberculosis in macrophages. This places Rv3351c in the same standing as HBHA and ESAT6, which are important factors in AECs and macrophages. Defining the mechanism(s) by which Rv3351c functions to aid pathogen survival within the host may lead to new drug or vaccine targets.

Ligand–Metal Ion Binding to Proteins: Investigation by ESI Mass Spectrometry

2005 ◽  
pp. 361-389 ◽  
Author(s):  
Noelle Potier ◽  
Hélène Rogniaux ◽  
Guillaume Chevreux ◽  
Alain Van Dorsselaer
Keyword(s):  
Mass Spectrometry ◽  
Metal Ion ◽  
Ion Binding ◽  
Metal Ion Binding ◽  
Esi Mass Spectrometry

scholarly journals DNA double-strand breaks in the Toxoplasma gondii-infected cells by the action of reactive oxygen species

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Haohan Zhuang ◽  
Chaoqun Yao ◽  
Xianfeng Zhao ◽  
Xueqiu Chen ◽  
Yimin Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Toxoplasma Gondii ◽  
Double Strand Breaks ◽  
Host Cells ◽  
Oxygen Species ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response ◽  
Infected Cells

Abstract Background Toxoplasma gondii is an obligate parasite of all warm-blooded animals around the globe. Once infecting a cell, it manipulates the host’s DNA damage response that is yet to be elucidated. The objectives of the present study were three-fold: (i) to assess DNA damages in T. gondii-infected cells in vitro; (ii) to ascertain causes of DNA damage in T. gondii-infected cells; and (iii) to investigate activation of DNA damage responses during T. gondii infection. Methods HeLa, Vero and HEK293 cells were infected with T. gondii at a multiplicity of infection (MOI) of 10:1. Infected cells were analyzed for a biomarker of DNA double-strand breaks (DSBs) γH2AX at 10 h, 20 h or 30 h post-infection using both western blot and immunofluorescence assay. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA), and ROS-induced DNA damage was inhibited by a ROS inhibitor N-acetylcysteine (NAC). Lastly, DNA damage responses were evaluated by detecting the active form of ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/CHK2) by western blot. Results γH2AX levels in the infected HeLa cells were significantly increased over time during T. gondii infection compared to uninfected cells. NAC treatment greatly reduced ROS and concomitantly diminished γH2AX in host cells. The phosphorylated ATM/CHK2 were elevated in T. gondii-infected cells. Conclusions Toxoplasma gondii infection triggered DNA DSBs with ROS as a major player in host cells in vitro. It also activated DNA damage response pathway ATM/CHK2. Toxoplasma gondii manages to keep a balance between survival and apoptosis of its host cells for the benefit of its own survival.

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.

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