Role of host fatty acid metabolism in Trypanosoma cruzi amastigote growth

 描述(申请人提供)：查加斯病寄生虫克氏锥虫具有感染多种有核细胞类型的能力，但其在心肌和平滑肌中的持久性是疾病进展的关键。像所有专性的细胞内病原体一样，克氏毛滴虫为了生存，将其新陈代谢需求与宿主相结合。如果将克氏锥虫与宿主细胞捆绑在一起的生化和细胞途径是已知的--特别是对心肌细胞--我们将处于更有利的地位，能够设计出破坏这些功能联系并抑制寄生虫感染的策略。然而，除了公认的对嘌呤、多胺和某些氨基酸的营养缺陷症外，克氏毛滴虫无鞭毛体的代谢依赖性在任何细胞类型中都没有被描述。这一建议建立在最近在HeLa细胞中进行的全基因组RNA干扰(RNAi)筛查的结果基础上，该筛查提供了支持细胞内T.ruzi感染的宿主易感因素的无偏见预览。在我们的筛选中确定的途径中，寄主脂肪酸代谢作为一种显著的候选途径出现，对克氏锥虫细胞内无鞭毛虫的生长产生积极的影响。拟议的研究试图确定细胞内的克氏锥虫无鞭毛体在哪里以及如何与宿主脂肪酸的氧化和合成途径相交，以及这种病原体的关键依赖关系在哪里。研究将利用诱导多能干细胞来源(IPSC)的人心肌细胞作为一种新的生物学相关的克氏毛滴虫感染模型。RNAi将与细胞外代谢通量分析和代谢质谱仪相结合，以确定宿主脂肪酸代谢的特定成分(脂实体和宿主酶)，这些成分对支持克氏毛滴虫感染人类心肌细胞至关重要。宿主脂肪酸代谢作为心肌细胞内生长的关键调节因子的分子和表型特征，将为了解这种重要的人类病原体的生物学及其将其代谢需求与宿主相结合的能力带来新的见解。对这些核心依赖关系的了解有可能为旨在将病原体与宿主脱钩的治疗策略提供信息。

 DESCRIPTION (provided by applicant): The Chagas' disease parasite Trypanosoma cruzi has the ability to infect many nucleated cell types, but its persistence in cardiac and smooth muscle is critical for disease progression. Like all obligate intracellular pathogens, T. cruzi mus couple its metabolic requirements to its host in order to survive. If the biochemical and cellular pathways that tether T. cruzi to its host cell were known - for cardiomyocytes in particular - we would be in a stronger position to design strategies to disrupt these functional ties and to inhibi parasite infection. However, with the exception of the well-recognized auxotrophies for purines, polyamines and certain amino acids, the metabolic dependencies of intracellular T. cruzi amastigotes have not been described in any cell type. This proposal builds on results from a recent genome-wide RNA interference (RNAi) screen in HeLa cells that offers an unbiased preview of host susceptibility factors that support intracellular T. cruzi infection. Among the pathways identified in our screen, host fatty acid metabolism emerged as a prominent candidate pathway that positively impacts intracellular T. cruzi amastigote growth. Proposed studies seek to determine where and how intracellular T. cruzi amastigotes intersect host fatty acid ß-oxidation and synthesis pathways and where the critical dependencies for this pathogen lie. Studies will exploit induced pluripotent stem cell-derived (iPSC) human cardiomyocytes as a new and biologically relevant T. cruzi infection model. RNAi will be combined with extracellular metabolic flux analyses and metabolic mass spectrometry to identify specific components (lipid entities and host enzymes) of host fatty acid metabolism that are critical to supporting human cardiomyocyte infection by T. cruzi. The proposed molecular and phenotypic characterization of host fatty acid metabolism as a key regulator of intracellular T. cruzi growth in cardiomyocytes will generate novel insights into the biology of this important human pathogen and its ability to integrate its metabolic needs with the host. Knowledge of these core dependencies has the potential to inform therapeutic strategies aimed at uncoupling the pathogen from its host.