Translational control during stage conversion of Toxoplasma, an opportunistic infection of HIV/AIDS

弓形虫（HIV/AIDS 的一种机会性感染）阶段转换过程中的转化控制

基本信息

批准号：
9226018
负责人：
William J Sullivan
金额：
$ 38.91万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-03-01 至 2021-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9226018
关键词：
AIDS therapy AIDS/HIV problem Acquired Immunodeficiency Syndrome Acute Address Antiparasitic Agents Automobile Driving Biochemical Chronic Clinical Cyst Data Development Disease Drug usage EIF-2alpha Eukaryota Eukaryotic Initiation Factor-2 Eye Follow-Up Studies Genes Genetic Genetic Translation Genome Goals Guanabenz HIV Infections Immunocompromised Host Immunosuppression In Vitro Individual Infection Life Link Malaria Mechanics Mediating Messenger RNA Molecular Mus Opportunistic Infections Parasites Pathway interactions Patients Pharmacology Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Plasmodium Polyribosomes Process Protein Biosynthesis Protein Dephosphorylation Protozoa Reporting Role Stress Testing Time Tissues Toxoplasma Toxoplasma gondii Toxoplasmosis Translating Translations effective therapy environmental change experimental study genetic analysis genetic regulatory protein inhibitor/antagonist insight latent infection novel strategies novel therapeutic intervention novel therapeutics public health relevance reactivation from latency response ribosome profiling

项目摘要

DESCRIPTION (provided by applicant): This proposal addresses molecular mechanisms that are central for formation and reactivation of latent stages of Toxoplasma gondii, a protozoan parasite that causes life-threatening opportunistic infection in AIDS/HIV patients. The ability of Toxoplasma to convert from its proliferative stage (tachyzoite) to latent tissue cysts (bradyzoite) gives rise to the life-threatening chronic opportunistic disease that afflicts AIDS patients. There is a vital need for new approaches for treatment of AIDS-toxoplasmosis, but this effort has been hindered by an insufficient understanding of the mechanisms by which the latent stage develops and reactivates. We discovered that phosphorylation of the Toxoplasma alpha subunit of eukaryotic initiation factor-2 (TgIF2α) contributes to bradyzoite development. Using polysome profiling, which we adapted for use in Toxoplasma, we showed that TgIF2α phosphorylation leads to preferential translation of a subset of mRNAs that are linked to bradyzoite development. Further support that translational control has critical functions during both replicative and lateny stages comes from our new studies using the drugs salubrinal (SAL) and guanabenz (GA), which inhibit TgIF2α dephosphorylation and block the reactivation of bradyzoites. Here we show that GA also protects mice acutely infected with Toxoplasma and decreases the number of cysts in chronically infected mice. Together, our genetic, biochemical, and pharmacological experiments support our hypothesis that translational control mediated by TgIF2α phosphorylation is critical for parasite stage interconversion. Our proposed experiments will address this hypothesis and 1) establish how TgIF2α kinases coordinate conversion to bradyzoites, 2) identify translationally controlled mRNAs initiating bradyzoite development and reconversion into replicating tachyzoites, and 3) determine the mechanisms underlying TgIF2α dephosphorylation and reactivation of infection. Completion of these aims will help define the mechanics of Toxoplasma stage conversion, with an eye towards developing critically needed novel therapies for AIDS-toxoplasmosis.

描述（由申请人提供）：该提案阐述了弓形虫潜伏期形成和重新激活的核心分子机制，弓形虫是一种原生动物寄生虫，可导致艾滋病/艾滋病毒患者发生危及生命的机会性感染。增殖期（速殖子）到潜伏组织囊肿（缓殖子）引起威胁生命的慢性机会性疾病，困扰艾滋病患者。迫切需要治疗艾滋病弓形虫病的新方法，但由于对潜伏期发展和重新激活的机制了解不够，这一努力受到阻碍。我们发现真核起始因子弓形虫α亚基的磷酸化。 2 (TgIF2α) 有助于缓殖子的发育。使用我们在弓形虫中使用的多核糖体分析，我们发现 TgIF2α磷酸化导致与缓殖子发育相关的一部分 mRNA 的优先翻译，这一点来自我们使用药物 salubrinal (SAL) 和 guanabenz (GA) 的新研究，进一步证明翻译控制在复制阶段和潜伏阶段都具有关键功能。抑制 TgIF2α 去磷酸化并阻止缓殖子的重新激活在此我们表明 GA 还可以保护急性弓形虫感染的小鼠并减少包囊数量。我们的遗传、生化和逻辑药理学实验共同支持了我们的假设，即 TgIF2α 磷酸化介导的翻译控制对于寄生虫阶段的相互转化至关重要，我们提出的实验将解决这一假设，并 1) 确定 TgIF2α 激酶如何协调转化。缓殖子，2) 识别翻译控制的 mRNA，启动缓殖子发育并重新转化为复制速殖子，3) 确定 TgIF2α 的潜在机制完成这些目标将有助于确定弓形虫阶段转换的机制，并着眼于开发艾滋病弓形虫病急需的新疗法。