Thio-dependent Antioxidants: A Novel Drug Target for Toxoplasma Gondii

硫代依赖性抗氧化剂：弓形虫的新药物靶点

• 批准号: 8849347
• 负责人: Rosa M. Andrade
• 金额: $ 18.87万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-15 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8849347
• 关键词: Acute; Affect; Antioxidants; Auranofin; Autophagocytosis; Autophagosome; Binding; Biological Assay; Biology; Blood - brain barrier anatomy; Brain; Cell physiology; Cells; Central Nervous System Toxoplasmosis; Cessation of life; Chickens; Chronic; Clinical Trials; Cloning; Confocal Microscopy; Data; Drug Kinetics; Drug Targeting; Drug resistance; Embryo; Entamoeba histolytica; Enzymes; FDA approved; Faculty; Folic Acid; Goals; Gold; Health; Hospitalization; Immune response; In Vitro; Inductively Coupled Plasma Mass Spectrometry; Infection; Inflammation; Inflammatory; Knock-out; Knowledge; Leishmania infantum; Ligation; Literature; Liver; Location; Long-Term Effects; Mass Spectrum Analysis; Measures; Mentors; Modeling; Molecular Biology; Molecular Immunology; Mus; Oxidoreductase; Parasites; Parasitic Diseases; Parasitology; Pathway interactions; Pattern; Penetration; Permeability; Peroxidases; Pharmaceutical Preparations; Phase I Clinical Trials; Proteins; Public Health; Reaction; Reactive Oxygen Species; Recombinants; Reporting; Resistance; Rheumatoid Arthritis; Role; Safety; Schistosoma mansoni; Solid; Speed; Staging; Sulfhydryl Compounds; System; Systems Biology; Testing; Thioredoxin; Time; Tissues; Toxic effect; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Training; Transmission Electron Microscopy; United States National Institutes of Health; Western Blotting; XRCC5 gene; antioxidant enzyme; base; career development; chemotherapeutic agent; drug development; experience; foodborne pathogen; in vitro activity; in vivo; killings; mouse model; multidisciplinary; new therapeutic target; novel; novel therapeutics; parasite invasion; prevent; research study; safety testing; thioredoxin glutathione reductase; thioredoxin reductase; trypanothione

DESCRIPTION (provided by applicant): Toxoplasmosis of the central nervous system can have potentially devastating long term effects. It is caused by Toxoplasma gondii and it is the second leading cause of hospitalizations (8%) and deaths (24%) among food borne pathogens in the US. Unfortunately, current available drugs have significant toxicity and have no effect over the bradyzoite/latent form while the impending threat of emergence of resistance to these drugs makes the discovery of new therapeutic targets a priority. In this proposal, we show that auranofin has in vitro activity against T. gondii and induces accumulation of reactive oxygen species in infected host cells while in vivo, it prevents death in 100% of chicken embryos (acute toxoplasmosis model) and modulates the host immune response preventing an overwhelming inflammatory reaction. Auranofin's likely target is the thiol-dependent anti-oxidant system as demonstrated by our own observations on Entamoeba histolytica (thioredoxin reductase), and on other parasites such as Leishmania infantum (trypanothione reductase), and Schistosoma mansoni (glutathione-thioredoxin reductase). The long term goal of this proposal is to elucidate the roles of the thiol-dependent antioxidant system in T. gondii biology which are largely unknown. The central hypothesis is that T. gondii thiol-dependent antioxidant system is essential for T. gondii biology, and is a viable drug target. Specific Aim 1 will determine that T. gondii thiol-dependent anti-oxidant enzymes (one thioredoxin reductase and two thioredoxin-dependent peroxidases) are auranofin targets. T. gondii knockout strains of these enzymes will be generated to corroborate these observations. Recombinant enzymes will be expressed and their pharmacokinetics of interaction with auranofin in vitro will be evaluated. Specific Aim 2 wil evaluate auranofin's in vivo activity in standard mouse models of acute and chronic toxoplasmosis and will measure auranofin concentrations in CNS by mass spectrometry to assess blood brain barrier penetration. Specific Aim 3 will evaluate the effect of auranofin on the host immune response given that it has an impressive effect on parasite clearance and decreasing host tissue inflammation in vivo chicken embryo model of acute toxoplasmosis. Tracking autophagy will be possible using GFP-LC3 mice which have been instrumental to study this cellular process. In vitro and in vivo assays will be conducted to determine autophagy activation and progression in the presence of auranofin and during T. gondii infection. This project has the potential of identifying a new anti-parasitic drug target, the T. gondii thiol-dependent anti-oxidant system, that can be exploited in drug development for the treatment of toxoplasma infection. Re-purposing of a FDA-approved drug with a proven safety profile can dramatically accelerate the time to clinical trials.

描述（由申请人提供）：中枢神经系统弓形虫病可能具有潜在的破坏性长期影响。它是由刚地弓形虫引起的，是美国食源性病原体中第二大住院原因（8%）和死亡原因（24%）。不幸的是，目前可用的药物有明显的毒性，并且没有效果