Metabolomic Characterisation of Host-Parasite-Interactions of the Apicomplexans Toxoplasma gondii and Plasmodium falciparum

刚地弓形虫和恶性疟原虫是重要的人类病原体。作为专性细胞内寄生虫，它们完全依赖于宿主营养物质的摄取。然而，目前尚不清楚营养供应如何影响它们的生理机能。弓形虫几乎可以感染任何温血动物，并且具有非常灵活的能量代谢。在没有外源葡萄糖的情况下，它可以利用其他碳源通过糖异生来满足其对己糖的需求。然而，非己糖营养物质对细胞内弓形虫的可用性和重要性在很大程度上是未知的。相比之下，红细胞内疟原虫完全依赖于葡萄糖摄取，但最近对临床分离物的转录组学研究表明，有条件地共同利用其他碳源。然而，缺乏提供自然营养环境的培养系统掩盖了疟原虫代谢的功能能力。为了解决这些基本问题，我们提出以下研究：1 .通过感染宿主细胞的代谢物谱鉴定弓形虫的碳源；2 .检测弓形虫体内糖异生的意义；3 .通过代谢足迹和同位素标记建立趋化性恶性疟原虫培养物以确定生理状态；4 .鉴定葡萄糖的个体作用及其与恶性疟原虫替代营养物质的多余性通过研究两种互补的顶复合体寄生虫在特定营养环境下的代谢结构和动力学来研究代谢宿主-寄生虫的相互作用。为此，我们将使用已建立的气相液相色谱-质谱和核磁共振分析平台。迫切需要了解寄生虫在生理情况下代谢的可塑性，以揭示关键的宿主-寄生虫相互作用，并评估杀虫药物的体内作用模式和耐药机制。

Toxoplasma gondii and Plasmodium falciparum are important human pathogens. As obligate intracellular parasites they depend entirely on the uptake of host nutrients. However, it remains unclear how the nutrient availability influences their physiology. T. gondii infects virtually any warm-blooded animal and has a very flexible energy metabolism. In the absence of exogenous glucose it can utilise other carbon sources to satisfy its need for hexoses via gluconeogenesis. However, the availability and significance of non-hexose nutrients for intracellular T. gondii is largely uncharacterised. In contrast, intraerythrocytic Plasmodium parasites absolutely depend on glucose uptake but recent transcriptomic studies on clinical isolates suggested a conditional co-utilisation of other carbon sources. However, a lack of culture systems that provide natural nutrient environments conceals the functional capabilities of the Plasmodiums metabolism. To address these fundamental questions we propose the following research:1 Identification of carbon sources for T. gondii by metabolite profiling of infected host cells2 Testing of the significance of gluconeogenesis in T. gondii3 Establishment of chemostat P. falciparum cultures to define physiological states via metabolic footprinting and isotopomer labelling4 Identification of individual roles of glucose and their redundancy with alternative nutrients in P. falciparumWe will characterise metabolic host-parasite interactions by investigating the metabolic structure and dynamics of two complementary apicomplexan parasites in context of defined nutrient environments. To this end we will use an established gas and liquid chromatography-mass spectrometry and NMR-based analytical platform. Understanding the plasticity of parasite metabolism in physiological scenarios is urgently required to reveal critical host-parasite interactions and to evaluate the in vivo mode of action and resistance mechanisms of parasitocidal drugs.