The adaptive potential of a survival artist: characterization of the<i>in vitro</i>interactions of<i>Toxoplasma gondii</i>tachyzoites with di-cationic compounds in human fibroblast cell cultures

Kropf, Christian; Debache, Karim; Rampa, Christoph; Barna, Fabienne; Schorer, Michelle; Stephens, Chad E.; Ismail, Mohamed A.; Boykin, David W.; Hemphill, Andrew

doi:10.1017/s0031182011001776

Cited by 30 publications

(26 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…N. caninum parasite load was determined by real-time PCR as previously described (15). Proliferation of T. gondii ME49, T. gondii CDPK1_G128M, and T. gondii CDPK1_wt tachyzoites was quantified as described previously (17). The parasite counts were calculated by interpolation from a standard curve with DNA equivalents from 1,000, 100, and 10 culture-derived tachyzoites included in each run.…”

Section: Methodsmentioning

confidence: 99%

In Vitro and In Vivo Effects of the Bumped Kinase Inhibitor 1294 in the Related Cyst-Forming Apicomplexans Toxoplasma gondii and Neospora caninum

Winzer

Müller

Aguado‐Martínez

et al. 2015

Antimicrob Agents Chemother

Self Cite

124

View full text Add to dashboard Cite

eWe report on the in vitro effects of the bumped kinase inhibitor 1294 (BKI-1294) in cultures of virulent Neospora caninum isolates Nc-Liverpool (Nc-Liv) and Nc-Spain7 and in two strains of Toxoplasma gondii (RH and ME49), all grown in human foreskin fibroblasts. In these parasites, BKI-1294 acted with 50% inhibitory concentrations (IC 50 s) ranging from 20 nM (T. gondii RH) to 360 nM (N. caninum Nc-Liv), and exposure of intracellular stages to 1294 led to the nondisjunction of newly formed tachyzoites, resulting in the formation of multinucleated complexes similar to complexes previously observed in BKI-1294-treated N. caninum beta-galactosidase-expressing parasites. However, such complexes were not seen in a transgenic T. gondii strain that expressed CDPK1 harboring a mutation (G to M) in the gatekeeper residue. In T. gondii ME49 and N. caninum NcLiv, exposure of cultures to BKI-1294 resulted in the elevated expression of mRNA coding for the bradyzoite marker BAG1. Unlike in bradyzoites, SAG1 expression was not repressed. Immunofluorescence also showed that these multinucleated complexes expressed SAG1 and BAG1 and the monoclonal antibody CC2, which binds to a yet unidentified bradyzoite antigen, also exhibited increased labeling. In a pregnant mouse model, BKI-1294 efficiently inhibited vertical transmission in BALB/c mice experimentally infected with one of the two virulent isolates Nc-Liv or Nc-Spain7, demonstrating proof of concept that this compound protected offspring from vertical transmission and disease. The observed deregulated antigen expression effect may enhance the immune response during BKI-1294 therapy and will be the subject of future studies. N eospora caninum is a cyst-forming apicomplexan parasite that is closely related to Toxoplasma gondii but exhibits distinct differences in transmission patterns, virulence, host specificity, immunogenetic aspects, and the pathology it induces. T. gondii causes toxoplasmosis in humans and many domestic and wildlife animals, with great economic impact especially in sheep but also in many other animal species (1). Human toxoplasmosis causes serious pathology in immune-suppressed individuals. In addition, if a seronegative mother acquires primary infection during pregnancy, human toxoplasmosis can lead to abortion, microcephalus and hydrocephalus, and other fetal abnormalities causing intellectual disability (2). N. caninum is a veterinary health problem and represents one of the most important infectious causes of bovine abortion, stillbirth, and the birth of weak calves, with an economic impact of over $1.3 billion (3-5). In addition, N. caninum causes neuromuscular disease in dogs, and neosporosis has also been detected in a wide range of other species of livestock and wild animals worldwide.Despite their differences, an important common feature of these parasites is their ability to invade and replicate within a wide range of cell types and tissues, where they reside in an intracellular parasitophorous vacuole, surrounded by a parasitophorous vacuole me...

show abstract

Section: Methodsmentioning

confidence: 99%

In Vitro and In Vivo Effects of the Bumped Kinase Inhibitor 1294 in the Related Cyst-Forming Apicomplexans Toxoplasma gondii and Neospora caninum

Winzer

Müller

Aguado‐Martínez

et al. 2015

Antimicrob Agents Chemother

Self Cite

124

View full text Add to dashboard Cite

show abstract

“…Transgenic ␤-galactosidase-expressing T. gondii (RH) and N. caninum (Nc-1) tachyzoites (kindly provided by David Sibley, Washington University, St. Louis, MO) were maintained by serial passage in Vero cells (23,24). Investigation of the inhibitory potential of the compounds was done as previously described (23,24,57). In short, confluent HFF grown in flat-bottom 96-well plates were infected with T. gondii or N. caninum tachyzoites at 10 3 parasites per well.…”

mentioning

confidence: 99%

“…After 2 h, compounds 2 to 18 (1 M for initial screening and 0.5 nM to 1 M for 50% inhibitory concentration [IC 50 ] determinations) were added, and after 72 h of cultivation, parasite proliferation was assessed by the addition of chlorophenol red-␤-D-galactopyranoside (Roche Diagnostics, Rotkreuz, Switzerland) in phosphate-buffered saline. A 570 was measured in a VersaMax 96-well multiplate reader (Bucher Biotec, Basel, Switzerland) at various time points (23,24).…”

mentioning

confidence: 99%

See 1 more Smart Citation

In VitroEffects of Novel Ruthenium Complexes in Neospora caninum and Toxoplasma gondii Tachyzoites

Barna

Debache

Vock

et al. 2013

Antimicrob Agents Chemother

Self Cite

View full text Add to dashboard Cite

bUpon the screening of 16 antiproliferative compounds against Toxoplasma gondii and Neospora caninum, two hydrolytically stable ruthenium complexes (compounds 16 and 18) exhibited 50% inhibitory concentrations of 18.7 and 41.1 nM (T. gondii) and 6.7 and 11.3 nM (N. caninum). To achieve parasiticidal activity with compound 16, long-term treatment (22 to 27 days at 80 to 160 nM) was required. Transmission electron microscopy demonstrated the rapid impact on and ultrastructural alterations in both parasites. These preliminary findings suggest that the potential of ruthenium-based compounds should thus be further exploited.T oxoplasma gondii and Neospora caninum are cyst-forming apicomplexan parasites that infect a wide range of hosts. In an immunocompetent host, infection with either parasite does not cause disease (1-3). N. caninum has emerged as one of the most important infectious causes of bovine abortion (4-6). In contrast, T. gondii causes toxoplasmosis in humans and many animal species, either in chronically infected individuals during a decrease in immunoreactivity or if a seronegative mother acquires a primary infection during pregnancy, leading to abortion or serious fetal abnormalities (7-9). Toxoplasmosis treatment is based on only a few chemotherapeutics with considerable adverse effects (10, 11). In Neospora-seropositive cattle, pregnancy and the associated immunomodulation are already sufficient to cause recrudescence, fetal damage, and abortion (2-6). Chemotherapy has been considered a promising option if effective drugs can be identified (12, 13). Several compounds were investigated in vitro (14-16), but only a few were evaluated in small-animal models (14,(17)(18)(19)(20)(21)(22)(23)(24).We have evaluated compounds originally synthesized as anticancer drugs. Currently used metal complexes (25-31) exhibit considerable toxicity. This has stimulated the interest in other compounds with more acceptable toxicity, such as ruthenium complexes (32-36). Effects of ruthenium compounds on some bacteria and parasites have been studied (37-46). "Classical ruthenium complexes" contain heteroatom ligands (e.g., azole derivatives), and NAMI-A and KP-1019 have been evaluated in phase I clinical trials for cancer treatment (47-49). Organometallic complexes are defined by at least one metal-carbon bond. The 6 -arene ruthenium(II) phosphite complexes 5, 6, 12, and 15 to 18 were characterized earlier (50), while [Ru( 6 -p-cymene)(bipyridine)Cl][Cl] 11 was synthesized as shown previously (51). Based on our experiences in the design of selective inhibitors of CYP11B2 (53) and CYP11B1 (54), the pyridine-based compounds 4, 7 to 10, and 14 were from a small in-house library of CYP enzyme inhibitors. 2,2=-Bipyridine 3 was obtained from Joachim W. Heinicke, Ernst Moritz Arndt University of Greifswald, Greifswald, Germany. The cytotoxic lipophilic imidazolium salt 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride 3 was synthesized as described previously (54-56). The arylimidamide DB745 2 (23) was kindly provided by David Bo...

show abstract

“…An example of a detailed study dealing with such aspects has been performed with T. gondii strains and pentamidine derivatives. 32 In vivo drug assessments in mice can be performed using the same models as described earlier for the vaccine studies. Ideally, a standardized mouse model should be used in order to render different experiments with different compounds performed in different laboratories comparable.…”

Section: Identification Of Suitable Chemotherapeuticsmentioning

confidence: 99%

Vaccines and drugs against Neospora caninum, an important apicomplexan causing abortion in cattle and other farm animals

Hemphill¹,

Müller²

2015

RIP

Self Cite

View full text Add to dashboard Cite

Abstract:The apicomplexan parasite Neospora caninum represents an important abortioncausing parasite in cattle. The economic impact of neosporosis has led to considerable investments to develop vaccines that would prevent infection and abortion. Live-attenuated vaccines have been shown to confer some protection against N. caninum infection, but may cause problems due to regulatory issues and other drawbacks. Therefore, efforts have been undertaken to develop recombinant subunit vaccines based on antigens involved in adhesion/invasion or other parasite-host cell interaction processes. Concerning chemotherapeutical agents, the currently known arsenal of active drugs that act against N. caninum is limited to a small number of compounds with suitable in vitro properties including low inhibition constants, parasitocidal effects, and low cytotoxicity. For in vivo studies, mostly small laboratory animal models that mimic cerebral infection, acute disease, and fetal loss upon infection during pregnancy have been applied for the assessment of vaccines or drug candidates. However, only a small number of recombinant vaccines and drug candidates have met the expectations, and small laboratory models for neosporosis need to be standardized in order to be able to compare the results of different laboratories. Few vaccines and compounds have made it into trials involving ruminant models such as cattle or sheep, including live-attenuated vaccines and the anticoccidial drug toltrazuril. We here summarize the current status of vaccine and drug development for neosporosis.

show abstract

The adaptive potential of a survival artist: characterization of thein vitrointeractions ofToxoplasma gondiitachyzoites with di-cationic compounds in human fibroblast cell cultures

Cited by 30 publications

References 43 publications

In Vitro and In Vivo Effects of the Bumped Kinase Inhibitor 1294 in the Related Cyst-Forming Apicomplexans Toxoplasma gondii and Neospora caninum

In Vitro and In Vivo Effects of the Bumped Kinase Inhibitor 1294 in the Related Cyst-Forming Apicomplexans Toxoplasma gondii and Neospora caninum

In VitroEffects of Novel Ruthenium Complexes in Neospora caninum and Toxoplasma gondii Tachyzoites

Vaccines and drugs against Neospora caninum, an important apicomplexan causing abortion in cattle and other farm animals

Contact Info

Product

Resources

About