Impact of Sickle-Trait on Transcriptional Regulation in P. Falciparum Parasites

镰状性状对恶性疟原虫转录调控的影响

• 批准号: 9315425
• 负责人: Steve Myer Taylor
• 金额: $ 23.54万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-21 至 2019-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9315425
• 关键词: African; Antiparasitic Agents; Attenuated; Binding Proteins; Biological Assay; Blood; Carrier Proteins; Cell surface; Child; Clinical; Data; Endothelium; Epidemiology; Erythrocytes; Falciparum Malaria; Future; Gene Expression; Genetic; Genetic Transcription; Goals; Growth; Hemoglobin; Hour; Impairment; In Vitro; Intervention; Investigation; Life; Malaria; Measures; Mediating; Mediator of activation protein; Membrane; Membrane Proteins; Modeling; Molecular; Molecular Genetics; Molecular Profiling; Multigene Family; Mutation; Outcome; Parasites; Parasitology; Pathogenesis; Pathogenicity; Pattern; Periodicity; Phenotype; Plasmodium falciparum; Population; Preventive; Protein Export Pathway; Proteins; Publishing; Reporting; Risk; Sampling; Sentinel; Series; Skeleton; Structure; Surface; Surface Antigens; Systems Biology; Testing; Time; Transcript; Transcriptional Regulation; Variant; Venous; Work; asexual; cohort; design; experimental study; field study; histidine-rich proteins; multidisciplinary; novel therapeutics; programs; protein transport; sickling; skills; tool; trafficking; trait; transcriptome; transcriptomics

Sickle-trait hemoglobin protects African children from severe-life threatening falciparum malaria, but the mechanisms of this protection are incompletely understood. Several lines of evidence support the notion that hemoglobin mutations disrupt the expression of parasite-derived proteins on the surface of the infected red blood cell (iRBC). These proteins on the iRBC surface mediate the pathogenicity of the parasite, and therefore identifying mechanisms by which their expression can be disrupted will offer new strategies to neutralize the parasite. In our preliminary experiments, sickle-trait dramatically alters the strong, periodic transcriptional program of P. falciparum as it matures within the RBC. More specifically, during early parasite maturation we observe consistent reductions in the expression of transcripts encoding parasite proteins that are essential for the organization and loading of Maurer’s clefts, including MAHRP1 and 2, REX 1 and 2, and SBP1; these proteins are necessary for normal trafficking of other parasite proteins to the iRBC surface. Notably, sickle-trait did not reduce the expression of transcripts encoding either surface proteins – including PfEMP1, KAHRP and other variant surface antigens – or components of the parasite translocation machinery, suggesting that sickle-trait specifically attenuates the efficient loading of protein transport machinery. In this project, we propose to systematically compare transcriptomes of Plasmodium falciparum parasites growing in normal and sickle-trait RBCs in order to identify parasite gene expression networks that are disrupted by sickle-trait. We hypothesize that sickle-trait will produce early, pervasive aberrations in the expression of parasite transcripts encoding proteins necessary for the assembly of protein export machinery. To test this, we will first cultivate field and reference parasites in normal and sickle-trait RBCs, densely sample parasite transcriptomes during the asexual blood stage, and serially compute gene expression networks. Additionally, we will assay parasite transcriptomes collected from malarious Malian children and compare parasite gene expression in those with normal and sickle-trait RBCs. Through this project, we will directly identify upstream components of the parasite’s protein export network that are inhibited by sickle-trait hemoglobin. Because sickle-trait serves as a model of attenuated parasite pathogenesis, these transcriptional profiles will be associated with clinical protection from malaria. The identification of transcripts and proteins that are impacted by sickle-trait will offer fresh targets for future interventions to neutralize the parasite.

镰状血红蛋白可以保护非洲儿童免受严重威胁生命的恶性疟疾， 这种保护的机制尚未完全了解。有几条证据支持 血红蛋白突变破坏了寄生虫衍生蛋白在细胞表面的表达， 受感染的红细胞（iRBC）。iRBC表面上的这些蛋白质介导细菌的致病性。 寄生虫，并因此确定其表达可以被破坏的机制， 提供了新的策略来中和寄生虫。在我们的初步实验中，镰状性状显著地 当恶性疟原虫在红细胞内成熟时，它改变了恶性疟原虫强的、周期性的转录程序。更 特别是，在早期寄生虫成熟过程中，我们观察到 转录本编码的寄生虫蛋白质是必不可少的组织和加载毛雷尔的 裂缝，包括MAHRP 1和2，雷克斯1和2，以及SBP 1;这些蛋白质是正常的 将其他寄生虫蛋白运输至iRBC表面。值得注意的是，镰刀性状并没有减少 表达编码表面蛋白的转录物-包括PfEMP 1、KAHRP和其他 变异表面抗原-或寄生虫易位机制的组成部分，这表明， 镰状性状特异性地减弱了蛋白质运输机器的有效装载。在这个项目中， 我们建议系统地比较恶性疟原虫寄生虫的转录组， 正常和镰状红细胞，以鉴定被破坏的寄生虫基因表达网络 镰刀形特征我们假设镰状性状会在大脑中产生早期的、普遍的畸变。 表达编码蛋白输出组装所必需的蛋白质的寄生虫转录物 机械.为了测试这一点，我们将首先培养正常和镰刀形性状的田间和参考寄生虫 红细胞，在无性血液阶段密集采样寄生虫转录组，并连续计算 基因表达网络此外，我们将分析从以下组织收集的寄生虫转录组： 疟疾的马里儿童，并比较寄生虫的基因表达，在那些正常和镰刀性状 红细胞。通过该项目，我们将直接识别寄生虫蛋白质的上游成分 被镰状血红蛋白抑制的输出网络。因为镰刀性状是一种 减毒寄生虫的发病机制，这些转录谱将与临床 预防疟疾。镰状性状影响的转录本和蛋白质的鉴定 将为未来的干预措施提供新的目标，以消除寄生虫。