Mapping the Human Metabolome Using Synthesis and Mass Spectrometry

Project Summary/Abstract The human metabolome remains mostly unknown, presenting a major bottleneck in the discovery of new biological mechanisms because structures are needed to predict function. There is a critical need for high-throughput, experimental strategies to characterize these unknowns. The overall goal of this project is to characterize unknown small molecules in humans using a combination of organic synthesis, mass spectrometry and public data mining. This proposal focuses on the synthesis and detection of two classes of small molecules critical to human physiology – neurotransmitter derivatives and sphingolipids. For the proposed projects, a strategy called reverse metabolomics will be used. Typically, in an untargeted metabolomics experiment, compounds are detected first, prioritized based on biological significance, then structurally identified. In the proposed reverse metabolomics experiments, however, the process is flipped. Compound classes of interest are first identified and synthesized, then their spectra are searched for in public metabolomics data to see if they are found in humans and if so, where. The proposed work will generate large MS/MS libraries of previously unidentified metabolites and all data will be made public. Additionally, a novel catalytic method for the one-step divergent synthesis of sphingolipids will be developed. While the proposed studies focus on two specific types of molecules, this strategy can be readily adapted to study other classes of biological molecules. Ultimately, this research enables the identification of new potential biomarkers, therapeutic targets, and pathogenic mechanisms.