Translation initiation factors driving persistence of Toxoplasma gondii bradyzoites in neurons

驱动弓形虫缓殖子在神经元中持续存在的翻译起始因子

• 批准号: 10556561
• 负责人: William J Sullivan
• 金额: $ 57.38万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-08 至 2027-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10556561
• 关键词: Acute; Address; Animals; Area; Automobile Driving; Binding; Brain; Cells; Chronic; Clinical; Collaborations; Collection; Complex; Cyst; Data; Development; Eukaryotic Initiation Factor-2; Goals; Human; Immune; Immunosuppression; Individual; Infection; Initiator Codon; Knowledge; Laboratories; Life; Messenger RNA; Modeling; Myocardium; Neurologic; Neurons; Nucleic Acid Regulatory Sequences; Open Reading Frames; Opportunistic Infections; Parasites; Patients; Peptide Initiation Factors; Pharmacotherapy; Phosphorylation; Phosphotransferases; Physiological; Population; Proliferating; Protein Biosynthesis; Protein Synthesis Induction; RNA; RNA Helicase; Recurrence; Regulatory Element; Ribosomes; Risk; Role; Scanning; Signal Transduction; Skeletal Muscle; Stress; Structure; Symptoms; System; Therapeutic Intervention; Tissues; Toxoplasma; Toxoplasma gondii; Toxoplasmosis; Transfer RNA; Translating; Translation Initiation; Translations; Work; combat; enhancer-binding protein AP-2; helicase; innovation; insight; mRNA Translation; mRNA capping; new therapeutic target; novel; novel therapeutics; prevent; programs; recruit; response; side effect; stress management; stress reduction; transcription factor; translatome

PROJECT SUMMARY The protozoan parasite Toxoplasma gondii can cause recurring opportunistic infections due to its ability to persist as a latent form (bradyzoite) within patients. There is no treatment that targets bradyzoite cysts, which reconvert into the destructive proliferative stage (tachyzoites) in the immune compromised. Patients suffering from reactivated toxoplasmosis frequently present with life-threatening neurological problems, underscoring the significance of bradyzoite cysts in the brain. A better understanding of the mechanisms that drive the development of bradyzoites in neurons is necessary to devise new therapies that prevent their formation and persistence. To address this need, we developed a novel model of spontaneous tissue cyst formation in neurons using Lund human mesencephalic (LUHMES) cells. We will use this innovative system to determine the mechanisms underlying the changes in protein synthesis that are required for bradyzoite formation. Based on our previous collaborative work, we hypothesize that translation initiation factors coordinate changes in 5’-leader sequences of key mRNAs, resulting in changes in protein synthesis that induce conversion to bradyzoites. Translation begins with the binding of an eIF4F complex to the 5’-cap, which then recruits eIF2, which carries Met-tRNA. We previously showed TgIF2 is phosphorylated during bradyzoite conversion, which lowers its abundance and can alter start codon selection. Aim 1 will determine how TgIF2 becomes phosphorylated and which mRNAs are preferentially translated during spontaneous bradyzoite conversion in neurons. Our RiboSeq approach will reveal areas within 5’-leaders that regulate translation, such as upstream open reading frames (uORFs) or secondary structures, the latter of which will be identified by generating the first RNA “structurome” for Toxoplasma in Aim 2. As these structures are resolved by helicase activity of eIF4F, Aim 2 will also delineate the functions of the multiple TgIF4F complexes we have uncovered in the parasites. Together, these studies will determine how cellular signals coordinate translation initiation factors to reprogram the translatome to trigger the spontaneous formation of bradyzoites in human neurons. Completion of this study will have a sustained high impact on the field by providing significant new insights into the complex mechanisms that Toxoplasma uses to persists in its host, which will reveal novel points for therapeutic intervention.

项目摘要 原生动物寄生虫弓形虫弓形虫可能会引起反复出现的机会感染，因为它的能力持续 作为患者中的潜在形式（Bradyzoite）。没有针对bradyzoite囊肿的治疗 在免疫受损中进入破坏性增殖阶段（tachyzoites）。患者患有 重新激活的弓形虫病经常出现威胁生命的神经系统问题，强调 大脑中铁二核囊肿的重要性。更好地理解驱动驱动的机制 在神经元中开发Bradyzoites是设计新疗法以防止其形成和 持久性。为了满足这一需求，我们开发了一种新型的神经元中赞助组织囊肿形成的模型 使用Lund人类的脑脑（Luhmes）细胞。我们将使用此创新系统来确定 蛋白质合成变化的基础机制是铁核形成所需的。基于 我们以前的合作工作，我们假设翻译计划因素协调了变化 关键mRNA的5'-Leader序列，导致蛋白质合成的变化，影响转化为 布拉迪二族人。翻译始于EIF4F复合物与5'-CAP的结合，然后报告EIF2， 带有Met-tRNA。我们先前表明TGIF2在Bradyzoite转化过程中被磷酸化，这是磷酸化的，这 降低其丰度并可以改变起始密码子的选择。 AIM 1将确定TGIF2如何变为 磷酸化，最好在自发的铁核转化率中翻译mRNA 神经元。我们的Riboseq方法将揭示5'领导者在调节翻译的区域，例如上游 开放式阅读帧（UORF）或辅助结构，后者将通过生成第一个来识别 AIM 2中的弓形虫的RNA“结构组”。由于这些结构是通过EIF4F的解旋酶活性解决的，AIM 2还将描绘我们在寄生虫中发现的多个TGIF4F复合物的功能。 这些研究将共同​​确定细胞信号如何协调翻译倡议因素重新编程 翻译组触发人神经元中的曲二核形成。这项研究的完成 通过对复杂机制提供重大新见解，将对该领域产生持续的高影响 弓形虫用来在其宿主中持续存在，这将揭示治疗干预的新颖点。