scholarly journals Anti- Toxoplasma gondii effect of Lumefantrine in vitro and in vivo

2020 ◽  
Author(s):  
Dawei Wang ◽  
Mengen Xing ◽  
Saeed El-Ashram ◽  
Yingying Ding ◽  
Xiaoyu Sang ◽  
...  
Keyword(s):  
Side Effects ◽  
Toxoplasma Gondii ◽  
Mtt Assay ◽  
Vero Cells ◽  
Protective Mechanism ◽  
High Dose ◽  
Mouse Tissues ◽  
Ifn Γ

Abstract Background: Toxoplasma gondii is an obligate intracellular protozoan parasite, which can infect almost all warm-blooded animals, including humans, leading to toxoplasmosis. Currently, the effective treatment for human toxoplasmosis is the combination of sulfadiazine and pyrimethamine. However, both drugs have serious side effects and toxicity in the host. Therefore, there is an urgent need for the discovery of new anti-Toxoplasma drugs with high potency and less or no side-effects. Methods: The cytotoxicity of sulfadiazine and lumefantrine to Vero cells was evaluated by the methyl thiazolyl tetrazolium (MTT) assay. And MTT assay was also used to detect the inhibitory effects of lumefantrine on parasites invasion and proliferation. Flow cytometry was conducted to further verify parasites proliferation. qPCR was performed to evaluate the parasite load in the mice after lumefantrine treatment. In order to determine whether lumefantrine treatment enhances Th1 or Th2 cytokine response, IFN-γ, IL-4, and IL-10 levels in the serum of mice were determined. Results: Our findings suggest that lumefantrine exerts activity against T. gondii by inhibiting its replication and invasion of Vero cells in vitro without being toxic to the cells. Furthermore, lumefantrine protected mice with acute toxoplasmosis from death to a certain extent and reduced the parasite burden in mouse tissues in vivo. In addition, a significant increase in IFN-γ production was observed in high dose lumefantrine-treated mice while IL-10 and IL-4 levels increased in low dose lumefantrine-treated mice. Conclusions: The results of this study demonstrated that lumefantrine may be a promising agent to treat toxoplamosis, and more experiments on the protective mechanism of lumefantrine should be undertaken in further studies.Key words: Toxoplasma gondii, Lumefantrine, anti-Toxoplasma gondii, Invasion, Proliferation

scholarly journals Determination of lumefantrine as an effective drug against Toxoplasma gondii infection – in vitro and in vivo study

Parasitology ◽  
2020 ◽  
pp. 1-7
Author(s):  
Dawei Wang ◽  
Mengen Xing ◽  
Saeed El-Ashram ◽  
Yingying Ding ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Side Effects ◽  
Toxoplasma Gondii ◽  
Parasite Burden ◽  
Vero Cells ◽  
Negative Control ◽  
Protective Mechanism ◽  
High Dose ◽  
Mouse Tissues

Abstract Toxoplasma gondii is an obligate intracellular protozoan parasite, which can infect almost all warm-blooded animals, including humans, leading to toxoplasmosis. Currently, the effective treatment for human toxoplasmosis is the combination of sulphadiazine and pyrimethamine. However, both drugs have serious side-effects and toxicity in the host. Therefore, there is an urgent need for the discovery of new anti-T. gondii drugs with high potency and less or no side-effects. Our findings suggest that lumefantrine exerts activity against T. gondii by inhibiting its proliferation in Vero cells in vitro without being toxic to Vero cells (P ≤ 0.01). Lumefantrine prolonged mice infected with T. gondii from death for 3 days at the concentration of 50 μg L−1 than negative control (phosphate-buffered saline treated only), and reduced the parasite burden in mouse tissues in vivo (P ≤ 0.01; P ≤ 0.05). In addition, a significant increase in interferon gamma (IFN-γ) production was observed in high-dose lumefantrine-treated mice (P ≤ 0.01), whereas interleukin 10 (IL-10) and IL-4 levels increased in low-dose lumefantrine-treated mice (P ≤ 0.01). The results demonstrated that lumefantrine may be a promising agent to treat toxoplasmosis, and more experiments on the protective mechanism of lumefantrine should be undertaken in further studies.

scholarly journals Development of a System To Study CD4+-T-Cell Responses to Transgenic Ovalbumin-Expressing Toxoplasma gondii during Toxoplasmosis

2004 ◽  
Vol 72 (12) ◽  
pp. 7240-7246 ◽  
Author(s):  
Marion Pepper ◽  
Florence Dzierszinski ◽  
Amy Crawford ◽  
Christopher A. Hunter ◽  
David Roos
Keyword(s):  
T Cells ◽  
T Cell ◽  
Toxoplasma Gondii ◽  
T Cell Responses ◽  
Cell Receptor ◽  
In Vivo Studies ◽  
Cell Responses ◽  
Ifn Γ

ABSTRACT The study of the immune response to Toxoplasma gondii has provided numerous insights into the role of T cells in resistance to intracellular infections. However, the complexity of this eukaryote pathogen has made it difficult to characterize immunodominant epitopes that would allow the identification of T cells with a known specificity for parasite antigens. As a consequence, analysis of T-cell responses to T. gondii has been based on characterization of the percentage of T cells that express an activated phenotype during infection and on the ability of these cells to produce cytokines in response to complex mixtures of parasite antigens. In order to study specific CD4+ T cells responses to T. gondii, recombinant parasites that express a truncated ovalbumin (OVA) protein, in either a cytosolic or a secreted form, were engineered. In vitro and in vivo studies reveal that transgenic parasites expressing secreted OVA are able to stimulate T-cell receptor-transgenic OVA-specific CD4+ T cells to proliferate, express an activated phenotype, and produce gamma interferon (IFN-γ). Furthermore, the adoptive transfer of OVA-specific T cells into IFN-γ−/− mice provided enhanced protection against infection with the OVA-transgenic (but not parental) parasites. Together, these studies establish the utility of this transgenic system to study CD4+-T-cell responses during toxoplasmosis.

scholarly journals Alpha/Beta Interferon and Gamma Interferon Synergize To Inhibit the Replication of Herpes Simplex Virus Type 1

2002 ◽  
Vol 76 (22) ◽  
pp. 11541-11550 ◽  
Author(s):  
Bruno Sainz ◽  
William P. Halford
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Herpes Simplex Virus Type ◽  
Vero Cells ◽  
Ifn Γ ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT In vivo evidence suggests that T-cell-derived gamma interferon (IFN-γ) can directly inhibit the replication of herpes simplex virus type 1 (HSV-1). However, IFN-γ is a weak inhibitor of HSV-1 replication in vitro. We have found that IFN-γ synergizes with the innate IFNs (IFN-α and -β) to potently inhibit HSV-1 replication in vitro and in vivo. Treatment of Vero cells with either IFN-β or IFN-γ inhibits HSV-1 replication by <20-fold, whereas treatment with both IFN-β and IFN-γ inhibits HSV-1 replication by ∼1,000-fold. Treatment with IFN-β and IFN-γ does not prevent HSV-1 entry into Vero cells, and the inhibitory effect can be overcome by increasing the multiplicity of HSV-1 infection. The capacity of IFN-β and IFN-γ to synergistically inhibit HSV-1 replication is not virus strain specific and has been observed in three different cell types. For two of the three virus strains tested, IFN-β and IFN-γ inhibit HSV-1 replication with a potency that approaches that achieved by a high dose of acyclovir. Pretreatment of mouse eyes with IFN-β and IFN-γ reduces HSV-1 replication to nearly undetectable levels, prevents the development of disease, and reduces the latent HSV-1 genome load per trigeminal ganglion by ∼200-fold. Thus, simultaneous activation of IFN-α/β receptors and IFN-γ receptors appears to render cells highly resistant to the replication of HSV-1. Because IFN-α or IFN-β is produced by most cells as an innate response to virus infection, the results imply that IFN-γ secreted by T cells may provide a critical second signal that potently inhibits HSV-1 replication in vivo.

scholarly journals p47 GTPases Regulate Toxoplasma gondii Survival in Activated Macrophages

2005 ◽  
Vol 73 (6) ◽  
pp. 3278-3286 ◽  
Author(s):  
Barbara A. Butcher ◽  
Robert I. Greene ◽  
Stanley C. Henry ◽  
Kimberly L. Annecharico ◽  
J. Brice Weinberg ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Acute Infection ◽  
Host Cells ◽  
Intracellular Growth ◽  
Latex Beads ◽  
Cellular Factors ◽  
Ifn Γ ◽  
Normal Inhibition

ABSTRACT The cytokine gamma interferon (IFN-γ) is critical for resistance to Toxoplasma gondii. IFN-γ strongly activates macrophages and nonphagocytic host cells to limit intracellular growth of T. gondii; however, the cellular factors that are required for this effect are largely unknown. We have shown previously that IGTP and LRG-47, members of the IFN-γ-regulated family of p47 GTPases, are required for resistance to acute T. gondii infections in vivo. In contrast, IRG-47, another member of this family, is not required. In the present work, we addressed whether these GTPases are required for IFN-γ-induced suppression of T. gondii growth in macrophages in vitro. Bone marrow macrophages that lacked IGTP or LRG-47 displayed greatly attenuated IFN-γ-induced inhibition of T. gondii growth, while macrophages that lacked IRG-47 displayed normal inhibition. Thus, the ability of the p47 GTPases to limit acute infection in vivo correlated with their ability to suppress intracellular growth in macrophages in vitro. Using confocal microscopy and sucrose density fractionation, we demonstrated that IGTP largely colocalizes with endoplasmic reticulum markers, while LRG-47 was mainly restricted to the Golgi. Although both IGTP and LRG-47 localized to vacuoles containing latex beads, neither protein localized to vacuoles containing live T. gondii. These results suggest that IGTP and LRG-47 are able to regulate host resistance to acute T. gondii infections through their ability to inhibit parasite growth within the macrophage.

A Uracil Auxotroph Toxoplasma gondii Exerting Immunomodulation to Inhibit Breast Cancer Growth and Metastasis

2021 ◽  
Author(s):  
Li-Qing Xu ◽  
Li-Jie Yao ◽  
Dan Jiang ◽  
Min Chen ◽  
Wen-Zhong Liao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Toxoplasma Gondii ◽  
Tumor Growth ◽  
Lung Metastasis ◽  
Tumor Bearing ◽  
Uracil Auxotroph ◽  
Ifn Γ

Abstract Background: Breast cancer is the most common cause of cancer-related death among women, and patients with triple-negative breast cancer (TNBC) have poor prognosis, so it is necessary to develop new effective therapies urgently. Recent studies have demonstrated that uracil auxotroph Toxoplasma gondii vaccine displays antitumor effects. Here, we examined the immunotherapy effects of an attenuated uracil auxotroph strain of T. gondii against 4T1 murine breast cancer.Methods: We constructed a uracil auxotroph strain, the orotidine 5′-monophosphate decarboxylase gene deleted strain of T. gondii (RH-Δompdc) with the CRISPR/Cas9 technology. Its virulence in vitro and in vivo was determined by parasite replication assay, plaque assay, the parasite burden detection in mice peritoneal fluids and the survival analysis of T. gondii infection mice. Its immune modulation ability was evaluated by cytokines detection. Its antitumor effect was evaluated after its in situ inoculation to 4T1 tumors in mouse model, the tumor volume was measured, the 4T1 lung metastasis was detected by H&E and Ki67 antibody staining, and the cytokines levels were measured by ELISA.Results: RH-Δompdc strain could proliferate normally with uracil supplement, however, it was unable to propagate without uracil and in vivo, which implicated that it is avirulent to the hosts. This mutant showed vaccine characteristics that it could induce intense immune responses both in vitro and in vivo by boosting the expression of inflammatory cytokines significantly. RH-Δompdc in situ inoculation to the 4T1 tumors in mice could inhibit the tumor growth, reduce the lung metastasis, promote the survival of the tumor-bearing mice, and also increase the secretion of Th1 cytokines IL-12 and IFN-γ both in serum and in the tumor microenvironment (TME). Conclusion: The uracil auxotroph RH-Δompdc inoculation to the 4T1 tumors stimulated the anti-infection and antitumor immunity in mice, resulted in the inhibition of tumor growth and metastasis, the promotion in survival of the tumor-bearing mice, and the increasing secretion of IL-12 and IFN-γ both in serum and in the TME. Our findings implied that the immunomodulation resulted by RH-Δompdc could be a potential antitumor strategy.

scholarly journals Curcumin a Multifaceted Compound with Hormetic Behaviour that Mediates an Intricate Crosstalk between Mitochondrial Biogenesis, Mitophagy, Mitophagic Death and Apoptosis

2017 ◽  
Author(s):  
Nathan Earl Rainey ◽  
Aoula Moustapha ◽  
Raphaelle Parker ◽  
Patrice Xavier Petit
Keyword(s):  
Cell Death ◽  
Mitochondrial Biogenesis ◽  
Calcium Release ◽  
Mitochondrial Outer Membrane ◽  
Protective Mechanism ◽  
High Dose ◽  
M Cell ◽  
Mitochondrial Outer Membrane Permeabilization

Curcumin, found in the rhizome of turmeric, has extensive therapeutic promises via its antioxidant, anti-inflammatory, and antiproliferative properties. Preclinical in vitro and in vivo data have shown curcumin to be an effective treatment for multiple cancers. These effects are drived by curcumin's ability to induce G2/M cell cycle arrest, induction of autophagy, activation of apoptotic pathways, disruption of molecular signaling, inhibition of invasion and metastasis, and by increasing the efficacy of existing chemotherapeutics. Here we focused on the hormetic behaviour of curcumin. Frequently, low doses of toxins and other stressors not only are harmless but also activate an adaptive stress whereas high dose activates acute responses like autophagy and cell death. This phenomenon is referred to as hormesis. Many molecules that cause cell death elicite an initial autophagic step that is a cytoprotective mechanism relying on elimination of dysfunctional structures intracellular, notably by mitophagy. This phenomenon is considered as a primarily protective mechanism against stressors. At higher doses, cells undergo mitochondrial outer membrane permeabilization due to calcium release from the endoplasmic reticulum and die. Herein, we address the complex crosstalk between the induced mitochondrial biogenesis, mitochondrial destabilization accompanied by mitophagy and cell death that can also be at play.

scholarly journals MOXIDECTIN AND IVERMECTIN INHIBIT SARS-COV-2 REPLICATION IN VERO E6 CELLS BUT NOT IN HUMAN PRIMARY AIRWAY EPITHELIUM CELLS

2021 ◽  
Author(s):  
Nilima Dinesh Kumar ◽  
Bram M. ter Ellen ◽  
Ellen M. Bouma ◽  
Berit Troost ◽  
Denise P. I. van de Pol ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Antiviral Effect ◽  
Vero Cells ◽  
In Vitro Models ◽  
World Health ◽  
Current Evidence ◽  
High Dose ◽  
Health Organization

Antiviral therapies are urgently needed to treat and limit the development of severe COVID-19 disease. Ivermectin, a broad-spectrum anti-parasitic agent, has been shown to have anti-SARS-CoV-2 activity in Vero cells at a concentration of 5 μM. These limited in vitro results triggered the investigation of ivermectin as a treatment option to alleviate COVID-19 disease. In April 2021, the World Health Organization stated, however, the following: “the current evidence on the use of ivermectin to treat COVID-19 patients is inconclusive”. It is speculated that the in vivo concentration of ivermectin is too low to exert a strong antiviral effect. Here, we performed a head-to head comparison of the antiviral activity of ivermectin and the structurally related, but metabolically more stable, moxidectin in multiple in vitro models of SARS-CoV-2 infection, including physiologically relevant human respiratory epithelial cells. Both moxidectin and ivermectin exhibited antiviral activity in Vero E6 cells. Subsequent experiments revealed that the compounds predominantly act on a step after virus cell entry. Surprisingly, however, in human airway-derived cell models, moxidectin and ivermectin failed to inhibit SARS-CoV-2 infection, even at a concentration of 10 μM. These disappointing results call for a word of caution in the interpretation of anti-SARS-CoV-2 activity of drugs solely based on Vero cells. Altogether, these findings suggest that, even by using a high-dose regimen of ivermectin or switching to another drug in the same class are unlikely to be useful for treatment against SARS-CoV-2 in humans.

scholarly journals Inducible Nitric Oxide Is Essential for Host Control of Persistent but Not Acute Infection with the Intracellular Pathogen Toxoplasma gondii

1997 ◽  
Vol 185 (7) ◽  
pp. 1261-1274 ◽  
Author(s):  
Tanya M. Scharton-Kersten ◽  
George Yap ◽  
Jeanne Magram ◽  
Alan Sher
Keyword(s):  
Nitric Oxide ◽  
Toxoplasma Gondii ◽  
Acute Infection ◽  
Protective Role ◽  
Major Mechanism ◽  
Reactive Nitrogen Intermediates ◽  
Ifn Γ ◽  
Inos Knockout Mice

The induction by IFN-γ of reactive nitrogen intermediates has been postulated as a major mechanism of host resistance to intracellular pathogens. To formally test this hypothesis in vivo, the course of Toxoplasma gondii infection was assessed in nitric oxide synthase (iNOS)−/− mice. As expected, macrophages from these animals displayed defective microbicidal activity against the parasite in vitro. Nevertheless, in contrast to IFN-γ−/− or IL-12 p40−/− animals, iNOSdeficient mice survived acute infection and controlled parasite growth at the site of inoculation. This early resistance was ablated by neutralization of IFN-γ or IL-12 in vivo and markedly diminished by depletion of neutrophils, demonstrating the existence of previously unappreciated NO independent mechanisms operating against the parasite during early infection. By 3-4 wk post infection, however, iNOS knockout mice did succumb to T. gondii. At that stage parasite expansion and pathology were evident in the central nervous system but not the periphery suggesting that the protective role of nitric oxide against this intracellular infection is tissue specific rather than systemic.

scholarly journals Inhibition of Different Lassa Virus Strains by Alpha and Gamma Interferons and Comparison with a Less Pathogenic Arenavirus

2004 ◽  
Vol 78 (6) ◽  
pp. 3162-3169 ◽  
Author(s):  
Marcel Asper ◽  
Thomas Sternsdorf ◽  
Meike Hass ◽  
Christian Drosten ◽  
Antje Rhode ◽  
...  
Keyword(s):  
Vero Cells ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
High Pathogenicity ◽  
Ifn Γ ◽  
Virus Strains

ABSTRACT The high pathogenicity of Lassa virus is assumed to involve resistance to the effects of interferon (IFN). We have analyzed the effects of alpha IFN (IFN-α), IFN-γ, and tumor necrosis factor alpha (TNF-α) on replication of Lassa virus compared to the related, but less pathogenic, lymphocytic choriomeningitis virus (LCMV). Three low-passage Lassa virus strains (AV, NL, and CSF), isolated from humans with mild to fulminant Lassa fever, were tested. Lassa virus replication was inhibited by IFN-α and IFN-γ, but not TNF-α, in Huh7 and Vero cells. The degree of IFN sensitivity of a Lassa virus isolate did not correlate with disease severity in human patients. Furthermore, cytokine effects observed for Lassa virus and LCMV (strains CH-5692, Armstrong, and WE) were similar. To address the mechanisms involved in the IFN effect, we used cell lines in which overexpression of IFN-stimulated proteins promyelocytic leukemia protein (PML) and Sp100 could be induced. Both proteins reside in PML bodies, a cellular target of the LCMV and Lassa virus Z proteins. Overexpression of PML or Sp100 did not affect replication of either virus. This, together with the previous finding that PML knockout facilitates LCMV replication in vitro and in vivo (M. Djavani, J. Rodas, I. S. Lukashevich, D. Horejsh, P. P. Pandolfi, K. L. Borden, and M. S. Salvato, J. Virol. 75:6204-6208, 2001; W. V. Bonilla, D. D. Pinschewer, P. Klenerman, V. Rousson, M. Gaboli, P. P. Pandolfi, R. M. Zinkernagel, M. S. Salvato, and H. Hengartner, J. Virol. 76:3810-3818, 2002), describes PML as a mediator within the antiviral pathway rather than as a direct effector protein. In conclusion, the high pathogenicity of Lassa virus compared to LCMV is probably not due to increased resistance to the effects of IFN-α or IFN-γ. Both cytokines inhibit replication which is relevant for the design of antiviral strategies against Lassa fever with the aim of enhancing the IFN response.

scholarly journals Artemisone and Artemiside Control Acute and Reactivated Toxoplasmosis in a Murine Model

2009 ◽  
Vol 53 (10) ◽  
pp. 4450-4456 ◽  
Author(s):  
Ildiko R. Dunay ◽  
Wing Chi Chan ◽  
Richard K. Haynes ◽  
L. David Sibley
Keyword(s):  
Side Effects ◽  
Toxoplasma Gondii ◽  
Murine Model ◽  
Acute Infection ◽  
Immunocompromised Patients ◽  
Artemisinin Derivatives ◽  
Parasite Replication ◽  
Derivatives Of

ABSTRACT Immunocompromised patients are at risk of developing toxoplasmosis, and although chemotherapy is available, standard treatments are often complicated by severe side effects. Artemisinin is a new highly potent antimalarial drug that has activity against Toxoplasma gondii in vitro. However, artemisinin derivatives have previously been ineffective in vivo using a rat model of toxoplasmosis. In the present study, the efficacy of several new artemisinin derivates was investigated for treatment of mice infected with the parasite Toxoplasma gondii. Artemiside and artemisone displayed better inhibition than either artemisinin or artesunate against the parasite in vitro. Artemiside and artemisone treatment controlled parasite replication in vivo, and mice survived the acute infection. In a murine model of reactivated toxoplasmosis, both drugs increased survival, although artemiside was more effective. These results indicate that these newer derivatives of artemisinin may have potential for treatment of toxoplasmosis.

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