Metabolic profiling by integrated analysis with LC-MS and MSI

Abstract

The metabolome is a group of small molecules that reflect phenotypic changes; this set of molecules is a potential source of biomarkers to predict the risk of disease development and progression. Therefore, it is necessary to establish a comprehensive and precise method to analyze the metabolome in biological samples. Mass spectrometry (MS) is one of the most suitable technologies to detect those molecules for metabolic profiling. In particular, liquid chromatography (LC)-MS-based methodology has been applied to various disease models and clinical samples, and biomarker candidates have been identified in previous studies. However, it is necessary to clarify their functions by in vivo research, and their molecular mechanisms in cells and/or tissues should be considered before the markers are deemed clinically applicable. MS imaging (MSI) is a promising technology that can visualize molecules on tissue surfaces without labeling and thus can clarify the distribution of biomarker candidates on tissue to evaluate the results by means of LC-MS-based analysis. Here, we describe the outline of the protocols for biomarker discovery by LC-MS and explain the utilization of integrated analyses using LC-MS and MSI to evaluate the function of biomarker candidates.