动物宿主与多种寄生生物相互作用的代谢组学分析

Infectious diseases, such as tuberculosis, AIDS, schistosomiasis and hepatitis, are endemic in China, brought heavy burden to public health and economic growth. They are caused by infecting human or animal hosts with corresponding pathogens, such as Mycobacterim tuberculosis, HIV virus and parasites etc. The underline factors contributing to the current endemic situation are lacking of effective immunization against the infection, early diagnostic methods and effective treatments. The problem becomes worse and more complicated by presence of multiple infective organisms, which is common phenomenon in clinics. Understanding the interaction between hosts and pathogens can provide important information for discovering diagnostic biomarkers and for designing effective new drugs. Metabolomics is a newly emerging analytical technique, which combines multivariate data analysis method with metabolic profiles generated from nuclear magnetic resonance (NMR) or mass spectrometry (MS). Since the birth of the technique, it has been applied to many research fields, such as the study of disease processes, drug toxicity, and interactions between animal hosts and parasites. The key tasks for metabonomic technique are to uncover metabonome information both quantitively and qualitively. Currently the structure elucidation of polar molecules from complex mixtures, such as urine and plasma is still a bottleneck. Therefore, in the current investigation, we will first of all aim to develop a fast, effective tool for structure elucidation of polar molecules from complex mixtures and then employ the developed metabonomic technique to investigate the interactions between animal host and infective organisms. To complete the tasks, we will design and prepare columns enabling separation and enrichment of polar metabolites and followed by incorporating the prepared columns into our existing hyphenated system (HPLC-SPE-CryoNMR-MS) and to finally achieve a fast, effective structure elucidation method. We will subsequently integrate NMR and MS metabolic profiling techniques to enhance sensitivity and structure elucidation power. We then apply the newly developed technique to investigate metabolic interactions between mice and Salmonella, and interactions between mice and multiple organisms, such as, schistosome- Salmonella. The altered metabolic pathways corresponding to single and double infections will subsequently be elucidated. Finally, these altered metabolic pathways will be further investigated using immuno assays. Summarization of the proposed project could generate metabolic mechanisms between hosts, providing important information for designing new sensitive drugs and could also shed some light on diagnosis of early infections in clinical settings.

寄生生物包括寄生虫、细菌和病毒。多种寄生生物的共感染是普遍现象，多寄生生物之间以及与宿主之间必然产生相互作用。研究宿主与多种寄生生物的相互作用是发展感染早期诊断的基础，是需要解决的重大科学问题。目前，寄生生物共染的研究主要集中在免疫学方面，也取得了一定的进展。但是，这些研究对宿主与多寄生生物的相互作用的分子表型和代谢机制尚无全面系统的认识。本项目拟以代谢组学为主要研究手段，在系统层面上揭示宿主与多种病原体相互作用的代谢表型这一关键科学问题。为此，我们将首先整合基于磁共振和质谱的代谢组学检测方法，实现对极性代谢物快速灵敏的结构确定。然后以小鼠为模型研究宿主被血吸虫-沙门氏菌共感染后代谢组的变化，并结合免疫学手段系统地分析多种病原体单独和共感染后不同时程的代谢组变化，以揭示宿主与多病原体相互作用的分子表型和代谢机制，为研究其它多寄生生物与宿主的相互作用提供研究手段。

多种寄生生物的共感染是普遍现象，多寄生生物之间以及与宿主之间必然产生相互作用。研究宿主与多种寄生生物的相互作用是发展感染早期诊断的基础，是需要解决的重大科学问题。为了解决这一问题，本项以代谢组学为主要研究手段，在系统层面上揭示宿主与多种病原体相互作用的代谢表型这一关键科学问题。我们首先发展了代谢组学新技术，实现对极性代谢物快速灵敏的结构确定，如氨基类代谢物。实现了核磁共振和色谱-质谱相结合的代谢组学分析方法，基本实现了代谢组学高覆盖、高灵敏的分析方法。发展了代谢组和宏基因组的整合分析方法。另外还发展了核磁共振代谢流的定量检测方法。我们进一步研究了小鼠单独感染沙门氏菌以及沙门氏菌与血吸虫感染。我们发现沙门氏菌感染导致脾脏组织产生大量的亚甲基丁二酸。鼠伤寒沙门氏菌共感染减少了血吸虫成虫和虫卵的数量，降低了日本血吸虫感染的小鼠的死亡率。此外，鼠伤寒沙门氏菌感染抵消了血吸虫病相关的代谢紊乱。免疫分析结果表明，共感染过程中实验小鼠免疫应答极化的转变是由依次感染的日本血吸虫和鼠伤寒沙门氏菌间接的相互作用造成的。最后，我们研究了HBV感染的代谢应答，发现HBV感染上调6-磷酸果糖氨基转移酶1（GFAT1）的转录水平，从而促进己糖胺的生物合成，还可以通过调控胆碱激酶A（CHKA）的转录水平来促进宿主细胞磷脂酰胆碱的合成，这是在HBV感染研究中首次报道的。抑制己糖胺生物合成和磷脂酰胆碱生物合成可以有效地抑制HBV 的复制和表达。这些研究结果为血吸虫和乙肝的治疗提供了新靶点和新思路。