High Throughput Lipidomics Analysis by MALDI/Ion Mobility Mass Spectrometry

描述(申请人提供)：代谢组学研究领域包括对一系列生物分子的研究，这些生物分子是细胞内酶反应的产物和底物。细胞代谢物的一个主要亚类是脂类，它们本身是一类不同的分子，范围从脂肪酸、类固醇、甘油脂、甘油磷脂、鞘磷脂和戊烯醇。在过去的十年里，血脂的测量有了显著的进步，这主要是由于质谱学和各种辅助技术的进步。在新陈代谢领域中，脂质构成了一类重要的化合物，因为这些分子发挥着核心作用，不仅通过形成脂质双层来分隔细胞内的隔室，而且这些分子还可以作为信号分子的前体、过氧化化学的靶标、DNA表达的调节因子，甚至是推动正常细胞生物学中关键过程的蛋白质所识别的实体。在每一类脂类中，都有密切相关的分子被称为分子物种，这增加了脂类混合物的复杂性和挑战性的分析。基于我们在使用MALDI成像质谱学方面取得的最新进展，我们建议有可能显着增加脂质分析的吞吐量，这样就可以在相当常规的基础上每天从数百个样本中获得重要的代谢信息。此外，我们建议这个平台可以被调整以提高对特定类别脂质的敏感性，并用于高通量脂肪组学分析，以解决涉及脂质合成和代谢的酶途径的特定问题。在某种程度上，这一方法将利用在鸟枪型脂质组学领域取得的进展，并结合MALDI质谱仪的高通量能力来产生定性和定量信息。初步数据显示，即使是未经处理的血清和血浆也可以获得关于这种液体中存在的复杂脂质混合物的信息，而不需要进行除稀释外的任何进一步的样品处理。这些数据可以在不到一分钟的时间内以一种形式获得，这种形式可以很容易地集成到工具中，以自动识别脂类以及定量存在的脂类丰度。为了进行这些研究，将使用先进的质谱学技术，包括离子迁移率技术，将脂肪离子从MALDI电离过程中产生的其他化合物和杂质中分离出来。即将开发的先进质谱学技术即使在没有离子迁移率的情况下也可以在许多实验室实施；然而，随着离子迁移率变得越来越广泛，它提供了目前其他质谱学系统所不具备的独特能力。 与公共卫生相关：从脂类成分的复杂程度以及理解这些样品中脂类的定量水平的需要出发，开发高通量方法来测量生物样品中存在的复杂的脂类混合物，包括血清、血浆、尿液以及细胞和组织，是具有挑战性的。提出了一种基于MALDI电离质谱仪平台生成脂类定量信息的新方法，该方法利用数据库检索鉴定脂类，利用内标定量自动将质谱仪信号转换为脂类单个分子物种的定量测量。分析吞吐量的提高可能对降低测量这些特定代谢物的成本具有重大影响，以便可以分析大量样本，包括在特定人类疾病研究中收集的1000年的样本，以揭示脂质生物化学在疾病过程中的参与。

DESCRIPTION (provided by applicant): The area of research termed metabolomics encompasses the study of a wide range of biomolecules that are products and substrates of enzymatic reactions within cells. One of the major subclasses of cellular metabolites are lipids, which they themselves are a diverse class of molecules that range from fatty acids, steroids, glycerolipids, glycerophospholipids, sphingolipids, and prenols. The measurement of lipids has significantly improved over the past decade, largely due to advances in mass spectrometry and various ancillary techniques. Lipids constitute an important class of compounds within the metabolomic sphere of interest because of the central role these molecules play, not only in separating compartments within cells through formation of lipid bilayers, but also through specific roles these molecules can play as precursor of signally molecules, targets for peroxidation chemistry, regulators of DNA expression, and even entities that are recognized by proteins that drive critical processes in normal cell biology. Within each class of lipids, there ae closely related molecules termed molecular species which increase the complexity of the lipid mixture and challenging analysis. Based upon recent advances we have made in using MALDI imaging mass spectrometry we propose that it will be possible to significantly increase the throughput of lipid analysis so that it will be possible to obtain important metabolomic information from several hundreds of samples per day on a fairly routine basis. Furthermore, we propose that this platform can be tuned to increase sensitivity for specific classes of lipids and used for high throughput lipidomic analysis to address specific questions concerning enzymatic pathways involved in lipid synthesis and metabolism. In part this approach will take advantage of the advances that have been made in the area of shotgun lipidomics coupled to the high throughput capability of MALDI mass spectrometry to yield both qualitative and quantitative information. Preliminary data shows that even untreated serum and plasma can yield information about the complex mixture of lipids present in this fluid without any further sample treatment except dilution. This data can be obtained within less than a minute in a form that can readily integrate into tools to automatically identify lipids as well as quantitate the abundance o lipids present. In order to carry out these studies, advanced mass spectrometric techniques will be used, including ion mobility technology to separate lipid ions from other compounds and impurities generated during the MALDI ionization process. The advanced mass spectrometric techniques to be developed can be implemented in many laboratories even without the ion mobility; however, ion mobility, as it becomes more widely available, provides a unique level of capability not currently present with other mass spectrometric system. PUBLIC HEALTH RELEVANCE: Development of high throughput methods to measure the complex mixture of lipids present in biological samples, including serum, plasma, urine, as well as cells and tissues is challenging from the stand point of the degree of complexity of lipid components, but also the need to understand the quantitative levels of lipids present in these samples. A novel method to generate quantitative information concerning lipids is proposed based upon a MALDI ionization mass spectrometry platform and the use of database searching to identify lipids and internal standard quantitation to automatically convert mass spectrometric signals into quantitative measures of individual molecular species of lipids. The improvement of analytical throughput could have a significant bearing upon the reduction of costs in measuring these specific metabolites so that a large number samples including those in the 1,000s that have been collected in studies of specific human disorders can be analyzed to reveal the involvement of lipid biochemistry in disease processes.