Spiroindolone that inhibits PfATPase4 is a potent, cidal inhibitor of Toxoplasma gondii tachyzoites in vitro and in vivo.
Ontology highlight
ABSTRACT:
SUBMITTER: Zhou Y
PROVIDER: S-EPMC3957861 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
Publications
Spiroindolone that inhibits PfATPase4 is a potent, cidal inhibitor of Toxoplasma gondii tachyzoites in vitro and in vivo.
Zhou Ying Y Fomovska Alina A Muench Stephen S Lai Bo-Shiun BS Mui Ernest E McLeod Rima R
Antimicrobial agents and chemotherapy 20131223 3
Here, we show that spiroindolone, an effective treatment for plasmodia, is also active against Toxoplasma gondii tachyzoites. In vitro, spiroindolone NITD609 is cidal for tachyzoites (50% inhibitory concentration [IC50], 1μM) and not toxic to human cells at ≥10μM. Two daily oral doses of 100 mg/kg of body weight reduced the parasite burden in mice by 90% (P=0.002), measured 3 days after the last dose. This inhibition of T. gondii tachyzoites in vitro and in vivo indicates that spiroindolone is a ...[more]
Similar Datasets
Project description:The triazine WR99210 [4,6-diamino-1,2-dihydro-2,2-dimethyl-1-(2,4,5-trichlorophenoxypropyloxy)-1,3,5 triazine] inhibits Toxoplasma gondii in vitro at nanomolar levels (P < 0.05). The 50% inhibitory concentration (IC(50)) was approximately 50 nM. It is a potent inhibitor in vitro and is also effective in vivo. Administration of WR99210 parenterally (i.e., intraperitoneally) reduced the mean number of RH strain tachyzoites present in peritoneal fluid substantially 4 days after intraperitoneal infection of mice. There was a mean of approximately 35 million parasites in control mice as contrasted with approximately 2 million parasites in mice treated with 1.25 mg WR99210/kg of body weight in a representative experiment (P < 0.05). In addition the prodrug PS-15 N'-[3-(2,4, 5-trichlorophenoxy)propyloxy]-N9-(1-methylethyl) imidocarbonimidicdiamide is converted to 4,6-diamino-1,2-dihydro-2,2-dimethyl-1-(2,4,5-trichlorophenoxypropyloxy)-1,3,5 triazine in vivo when the prodrug is administered orally. PS-15 administered by gavage also reduced intraperitoneal RH strain T. gondii tachyzoite numbers. WR99210 has high efficacy and relatively low toxicity because of its substantial effect on T. gondii dihydrofolate reductase (DHFR) but not the mammalian host DHFR. Amino acid sequences of T. gondii, Plasmodium falciparum, and Homo sapiens DHFRs were compared. It is of interest that of the DHFR amino acids considered to be interacting with WR99210 in P. falciparum within interatomic distances within 3 to 5 A, four of eight were shared with T. gondii DHFR. H. sapiens also shared four amino acids thought to be interacting with WR99210. Efficacy of intraperitoneal administration of WR99210 and peroral administration of PS-15 demonstrate the potential usefulness of this class of compounds in treatment of toxoplasmosis administered either parenterally or perorally. The recent development program for this class of antimicrobials as antimalarials makes our proof of principle of improved efficacy of triazines (compared with the gold standard treatment, pyrimethamine) against T. gondii especially promising.
| S-EPMC1196210 | biostudies-literature
Project description:Acridone derivatives, which have been shown to have in vitro and in vivo activity against Plasmodium spp, inhibit Toxoplasma gondii proliferation at picomolar concentrations. Using enzymatic assays, we show that acridones inhibit both T. gondii cytochrome bc1 and dihydroorotate dehydrogenase and identify acridones that bind preferentially to the Qi site of cytochrome bc1. We identify acridones that have efficacy in a murine model of systemic toxoplasmosis. Acridones have potent activity against T. gondii and represent a promising new class of preclinical compounds.
| S-EPMC8273083 | biostudies-literature
Project description:Toxoplasma gondii tachyzoites were loaded with the fluorescent indicator fura 2 to investigate the transport mechanisms involved in maintaining their intracellular Ca2+ homoeostasis. The mitochondrial ATPase inhibitor oligomycin and the endoplasmic-reticulum Ca(2+)-ATPase inhibitor thapsigargin increased the intracellular Ca2+ concentration ([Ca2+]i), thus indicating the requirement for ATP and the involvement of the endoplasmic reticulum in maintaining intracellular Ca2+ homoeostasis. The effect of thapsigargin was more accentuated in the presence of extracellular Ca2+, clearly showing that, as occurs with other eukaryotic cells, depletion of intracellular Ca2+ pools led to an increase in the uptake of Ca2+ from the extracellular medium. In addition to these results, we found evidence that, in contrast with what occurs in mammalian cells, T. gondii tachyzoites possess a significant amount of Ca2+ stored in an acidic compartment, termed the acidocalcisome, as indicated by: (1) the increase in [Ca2+]i induced by bafilomycin A1 (a specific inhibitor of H(+)-ATPases), nigericin (a K+/H+ exchanger) or the weak base NH4Cl, in the nominal absence of extracellular Ca2+ to preclude Ca2+ entry; and (2) the effect of ionomycin, a Ca(2+)-releasing ionophore that cannot take Ca2+ out of acidic organelles and that was more effective after alkalinization of these compartments by addition of bafilomycin A1, nigericin or NH4Cl. Considering the relative importance of the ionomycin-releasable and the ionomycin + NH4Cl-releasable Ca2+ pools, it is apparent that T. gondii tachyzoites contain a significant amount of Ca2+ stored in acidocalcisomes.
| S-EPMC1216957 | biostudies-other
Project description:Toxoplasma gondii causes substantial morbidity, mortality, and costs for healthcare in the developed and developing world. Current medicines are not well tolerated and cause hypersensitivity reactions. The dihydrotriazine JPC-2067-B (4, 6-diamino-1, 2-dihydro-2, 2-dimethyl-1-(3'(2-chloro-, 4-trifluoromethoxyphenoxy)propyloxy)-1, 3, 5-triazine), which inhibits dihydrofolate reductase (DHFR), is highly effective against Plasmodium falciparum, Plasmodium vivax, and apicomplexans related to T. gondii. JPC-2067-B is the primary metabolite of the orally active biguanide JPC-2056 1-(3'-(2-chloro-4-trifluoromethoxyphenyloxy)propyl oxy)- 5-isopropylbiguanide, which is being advanced to clinical trials for malaria. Efficacy of the prodrug JPC-2056 and the active metabolite JPC-2067-B against T. gondii and T. gondii DHFR as well as toxicity toward mammalian cells were tested.Herein, we found that JPC-2067-B is highly effective against T. gondii. We demonstrate that JPC-2067-B inhibits T. gondii growth in culture (IC50 20 nM), inhibits the purified enzyme (IC50 6.5 nM), is more efficacious than pyrimethamine, and is cidal in vitro. JPC-2067-B administered parenterally and the orally administered pro-drug (JPC-2056) are also effective against T. gondii tachyzoites in vivo. A molecular model of T. gondii DHFR-TS complexed with JPC-2067-B was developed. We found that the three main parasite clonal types and isolates from South and Central America, the United States, Canada, China, and Sri Lanka have the same amino acid sequences preserving key binding sites for the triazine.JPC-2056/JPC-2067-B have potential to be more effective and possibly less toxic treatments for toxoplasmosis than currently available medicines.
| S-EPMC2254147 | biostudies-literature
Project description:Drug treatment for toxoplasmosis is problematic, because current drugs cannot eradicate latent infection with Toxoplasma gondii and can cause bone marrow toxicity. Because latent infection remains after treatment, relapse of infection is a problem in both infections in immunocompromised patients and in congenitally infected patients. To identify lead compounds for novel drugs against Toxoplasma gondii, we screened a chemical compound library for anti-Toxoplasma activity, host cell cytotoxicity, and effect on bradyzoites. Of 878 compounds screened, 83 demonstrated >90% parasite growth inhibition. After excluding compounds that affected host cell viability, we further characterized two compounds, tanshinone IIA and hydroxyzine, which had IC50 values for parasite growth of 2.5 ?M and 1.0 ?M, respectively, and had no effect on host cell viability at 25 ?M. Both tanshinone IIA and hydroxyzine inhibited parasite replication after invasion and both reduced the number of in vitro-induced bradyzoites, whereas, pyrimethamine, the current therapy, had no effect on bradyzoites. Both tanshinone IIA and hydroxyzine are potent lead compounds for further medicinal chemistry. The method presented for evaluating compounds for bradyzoite efficacy represents a new approach to the development of anti-Toxoplasma drugs to eliminate latency and treat acute infection.
| S-EPMC5469451 | biostudies-literature
Project description:The killer peptide KP is a synthetic decapeptide derived from the sequence of the variable region of a recombinant yeast killer toxin-like microbicidal single-chain antibody. KP proved to exert significant activities against diverse microbial and viral pathogens through different mechanisms of action, but little is known of its effect on apicomplexan protozoa. The aim of the present study was to evaluate the in vitro activity of KP against Toxoplasma gondii, a globally widespread protozoan parasite of great medical interest. The effect of KP treatment and its potential mechanism of action on T. gondii were evaluated by various methods, including light microscopy, quantitative PCR, flow cytometry, confocal microscopy, and transmission electron microscopy. In the presence of KP, the number of T. gondii tachyzoites able to invade Vero cells and the parasite intracellular proliferation were significantly reduced. Morphological observation and analysis of apoptotic markers suggested that KP is able to trigger an apoptosis-like cell death in T. gondii. Overall, our results indicate that KP could be a promising candidate for the development of new anti-Toxoplasma drugs with a novel mechanism of action.
| S-EPMC5920037 | biostudies-literature
Project description:Pyrimethamine which is a main anti-Toxoplasma gondii drug has a serious side and toxic effects on the host. Accordingly, the development of new treatment options for toxoplasmosis with less toxic effects, low teratogenicity and parasiticidal effect against the various stage of T. gondii are dramatically crucial. Currently, natural molecules from scorpion and snake venoms are widely used as an alternative treatment against human disease, these compounds considered to be safe and to have low toxicity in comparison with synthetic drugs. Therefore, the goal of our study was to investigate the anti-Toxoplasma gondii activities of Hemiscorpius lepturus venom. We measured cytotoxicity of H. lepturus whole venom on Vero cells as well as effectiveness of this compound on viability of T. gondii applying colorimetric assay, according to mitochondrial oxidation of the MTT reagent (Methylthiazol tetrazolium 98%). The results of this study indicated that the H. lepturus whole venom has an anti-Toxoplasma effects with less toxic effect on Vero cells. Also, the T. gondii tachyzoites were treated with H. lepturus venom reached better results in comparison with Pyrimethamine-treated group. This research will serve as a base for future studies on toxoplasmosis and suggest a role for scorpion venom in promoting natural drugs.
| S-EPMC6667720 | biostudies-literature
Project description:AIM: To examine three lineages of Toxoplasma gondii RH strain in terms of performance in the dye test, culture, and gene expression. METHODS: Historical data (culture growth and performance in the dye test) from three lineages of RH strain tachyzoites (B, J, and Q) that had been continuously cultured in HeLa cells was assessed. Tachyzoite harvests obtained during continuous cell culture were retrieved from liquid nitrogen and cultured in HeLa cells, providing mRNA that was extracted and used to study gene expression using random amplified polymorphic DNA analysis at different stages of lineage adaptation to continuous culture. RESULTS: The B and Q lineages consistently produced tachyzoites that were successfully used in the dye test and their gene expression was stable after multiple passages. The J lineage had unpredictable growth, tachyzoites unsuitable for use in the dye test, and changing gene expression with multiple passage. CONCLUSION: This study has explained some anomalies in the performance of different stocks of T gondii, and suggests that lineages that are still evolving in cell culture should be avoided.
| S-EPMC1770330 | biostudies-other
Project description:Toxoplasma gondii is a pervasive apicomplexan parasite that can cause severe disease and death in immunocompromised individuals and the developing foetus. The treatment of toxoplasmosis often leads to serious side effects and novel drugs and drug targets are therefore actively sought. In 2014, Mageed and colleagues suggested that the T. gondii pantothenate synthetase, the enzyme responsible for the synthesis of the vitamin B5 (pantothenate), the precursor of the important cofactor, coenzyme A, is a good drug target. Their conclusion was based on the ability of potent inhibitors of the M. tuberculosis pantothenate synthetase to inhibit the proliferation of T. gondii tachyzoites. They also reported that the inhibitory effect of the compounds could be antagonised by supplementing the medium with pantothenate, supporting their conclusion that the compounds were acting on the intended target. Contrary to these observations, we find that compound SW314, one of the compounds used in the Mageed et al. study and previously shown to be active against M. tuberculosis pantothenate synthetase in vitro, is inactive against the T. gondii pantothenate synthetase and does not inhibit tachyzoite proliferation, despite gaining access into the parasite in situ. Furthermore, we validate the recent observation that the pantothenate synthetase gene in T. gondii can be disrupted without detrimental effect to the survival of the tachyzoite-stage parasite in the presence or absence of extracellular pantothenate. We conclude that the T. gondii pantothenate synthetase is not essential during the tachyzoite stage of the parasite and it is therefore not a target for drug discovery against T. gondii tachyzoites.
| S-EPMC10102396 | biostudies-literature
Project description:Treatment for toxoplasmosis is not completely successful because of their unwanted side effects, and new treatments are needed. Imiquimod has ability to moderate immune response and used to treat a wide variety of infections and tumors. The aim of the present study was to evaluate the effect of imiquimod on the tachyzoites of T. gondii and infected macrophages in vitro and in BALB/c mice. The viability of T. gondii was assessed in the presence of various concentrations of imiquimod by direct counting after 6 and 24 h. The MTT assay was used to identify the viability of uninfected macrophages. The apoptotic effects were determined with flow cytometry on the tachyzoites and infected macrophages. For evaluation of parasite load in pre-treatment or post-treatment of macrophages Quantitative real time PCR (qPCR) was performed. For in vivo experiments, BALB/c mice received imiquimod before and after challenge with parasites. The mortality rate of mice, parasite numbers in spleen, and the INF-? and IL-4 cytokine levels in spleen lymphocytes were evaluated. Imiquimod demonstrated anti-Toxoplasma effects by reducing the number of tachyzoites. The results of flow cytometry for drug-treated tachyzoites showed that apoptosis did not rise significantly relative to the control group (p < 0.05). Moreover, apoptosis was enhanced in infected macrophages as the concentration of imiquimod was reduced. The parasitic burden in imiquimod pretreated macrophages was significantly lower than those treated after infection (p < 0.01). A marked reduction was observed in survival rate, parasite load and INF-? level in BALB/c mice that received imiquimod before parasitic challenge relative to those received drug after parasitic challenge (p < 0.01). Overall, imiquimod in the pretreated group had greater anti-Toxoplasma effects than imiquimod in posttreated group in vitro and in vivo. imiquimod may be considered as a candidate for use against Toxoplasmosis both therapeutically and prophylactically.
| S-EPMC7412631 | biostudies-literature