Headspace Metabolomics for Non-invasive Biomarker Discovery

最近在先进的质谱分析和数据处理工具方面的发展导致了点护理检测（POCT）高效设计的繁荣。方法是基于代谢组学研究和创新传感器技术发现新的疾病生物标志物。呼气分析是POCT的理想选择，因为它的非侵入性；然而，它远不如血液检测发达。然而，各种各样的疾病，如肺癌和喉癌、帕金森氏病和肺病，已被证明具有特定的挥发性生物标志物“指纹”，迄今为止，这些生物标志物尚未得到充分利用。因此，我们建议将代谢组学推向前沿，研究微生物群落的挥发物，以探索尚未开发的诊断和筛查机会。该项目需要开发一种新的管道，用于在临床相关场景中发现呼吸挥发物（挥发性代谢物）中的生物标志物。关注口腔/肠道微生物组（生活在粘膜和口腔之间的好氧/厌氧界面的复杂细菌群落），影响口腔健康（龋齿发生，牙周炎，牙龈炎）以及全身和心脏代谢健康，我们提出了一种独特的从实验到临床实践的过渡方法。在项目期间，将使用具有代表性的挥发性代谢物的标准混合物开发非目标挥发性的分析方法。这将包括采样，气相色谱-质谱分析和数据处理方法。利用Gordon Ramage教授实验室建立的现有体外多物种生物膜模型，在体外进行分批生物膜发酵微环境（体外），然后进行各种处理（如碳和氮的可用性）。管道的统计分析工具将从Gauchotte-Lindsay小组的现有工具调整为这些样品的挥发物，并将识别与处理变化相关的生物标志物。最后，挥发物特征将在健康人类志愿者和患有牙周炎和肥胖相关内毒素血症的志愿者中使用相同的分析管道进行，在使用饮食或药物方法调节生物膜（体内）干预之前，期间和之后。在这里，最终可以用于即时护理传感器的生物标志物将被识别出来。目的和目标：该项目将回答以下问题：我们是否可以使用基于非侵入性呼吸采样的新型代谢组学方法识别口腔健康的挥发性生物标志物作为系统健康的门户？其目的是产生一份化合物的候选名单（最佳指纹），可以用于低成本的即时护理传感器或芯片实验室。研究方法的新颖性：代谢组学研究大多是在血液、尿液或粪便等生物样本中进行的。越来越多的证据表明，微生物活动调节了人体的广泛功能，并且患有相关疾病的患者的微生物组与健康受试者不同。反过来，最近的研究也表明，微生物群落上方空间的化学成分是开启的代谢和分解代谢途径的代表。因此，我们建议将代谢组学推向前沿，研究微生物群落的挥发物，以探索尚未开发的诊断和筛查机会。

Recent developments in advanced mass spectrometry and data treatment tools have led to a boom in the efficient design of point-of-care testing (POCT). Approaches are based on novel disease biomarkers discovery with metabolomics studies and innovative sensor technologies. Breath analysis is an ideal candidate for POCT because of its non-intrusive nature; it is, however, much less developed than blood testing. Nevertheless, diseases as varied as lung and throat cancers, Parkinson's disease and pulmonary diseases have been shown to possess specific volatile biomarkers "fingerprint" which have been, to date, under-utilised. We propose therefore to move metabolomics to the headspace and study the volatilome of microbial communities to explore yet untapped opportunities for diagnostic and screening.This project entails the development of a novel pipeline for biomarker discovery in the breath volatilome (volatile metabolites), in clinically-relevant scenarios. Focusing on the oral/gut microbiome (a complex community of bacteria living at the aerobic/anaerobic interface between mucosa and oral cavity), which influences oral health (cariogenesis, periodontitis, gingivitis) and systemic and cardio-metabolic health, we propose a unique transitional approach from bench to clinical practice.During the project, analytical methods will be developed for non-targeted volatilomics using standard mixtures of representative volatile metabolites. This will include sampling, GC-MS analysis and data processing methods. Batch biofilm fermentation microcosms (in vitro) with then be ran with various treatments (such as carbon and nitrogen availability), making use of existing in vitro multi-species biofilm models established in Prof Gordon Ramage's lab. The statistical analysis tool of the pipeline will be adapted from existing tools in the Gauchotte-Lindsay group to the volatilome of these samples and biomarkers that correlate with the variations in treatment will be identified. Finally, volatilome characterisation will be carried out using the same analytical pipelines in groups of healthy human volunteers and volunteers with periodontitis and obesity-associated endotoxaemia before, during and after an intervention using dietary or pharmacological approaches to modulate the biofilm (in vivo). Here biomarkers that could eventually be employed in point-of-care sensors will be identified.Aims and objectives:This project will answer the question: Can we identify volatile biomarkers for oral health as a portal to systemic health using a novel metabolomics approach based on non-intrusive breath sampling? The aim is to produce a shortlist of chemical compounds (optimal fingerprint) that could be employed in a low-cost point-of-care sensors or lab-on-a-chip.Novelty of the research methodology:Metabolomics studies have mostly been carried out in biological samples such as blood, urine or faeces. There is growing evidence that microbial activities regulate a broad range of functions in the human body and that patients with related illness(es) present different microbiome than healthy subjects. In turns, recent research also demonstrates that the chemical composition of the headspace above a microbial community is representative of the turned-on metabolic and catabolic pathways. We propose therefore to move metabolomics to the headspace and study the volatilome of microbial communities to explore yet untapped opportunities for diagnostic and screening.