Resolution of Lipid Structural Diversity for Threat-Agnostic Signature Development
EMSL Project ID
51808
Abstract
Development of threat-agnostic biosignatures is critical for detection of and response to biological threats that go beyond the historical list-based approach. Lipids are a class of structurally diverse biomolecules that hold great promise as relevant threat-agnostic biosignatures, yet the fundamental challenge of resolving and decoding structural differences among lipids remains an obstacle in the pursuit of signature development. While the current standard approaches for lipid analysis identify general structural characteristics, such as the class of lipids and carbon chain length, many structural features that influence the function of lipid molecules cannot be defined. For example, the position of double bonds or branching sites on the lipid molecule are not currently structurally resolved. These characteristics are known to influence lipid function and offer chemotaxonomic classification, and may be critical in differentiating, for example, threat vs. non-threat.We seek to advance PNNL lipidomics capabilities to enable a more complete lipid structural resolution. The current standard lipid analysis pipeline uses a liquid chromatography - tandem mass spectrometry (LC-MS/MS) platform, which can identify that structural isomers exist but cannot define what the structural differences are. Structural analysis of complex lipids remains stymied due to spectral complexity and the inability to resolve low abundance lipids. To address these challenges, we propose to (1) incorporate ion mobility mass spectrometry (LC-IMS-MS/MS) analysis to enable greater separation of lipid species, and (2) integrate ozonolysis to pinpoint the following lipid structural features: sn position of acyl chains, position and orientation of double bonds, and presence and position of methyl branches, hydroxyl groups, and cyclopropyl rings along the fatty acid chains.
Advancements in lipid analysis will be demonstrated by defining the lipid structures in antimicrobial resistant (AMR) and antimicrobial susceptible (AMS) biothreat organisms Yersinia pestis and Francisella tularensis. AMR is a widespread health problem for which testing is time consuming and labor intensive, and a previous PNNL study has suggested that similar lipid changes may exist across AMR strains of different bacteria. Differentiation of lipid structures in this threat (AMR) vs. non-threat (AMS) model system would additionally aid in the development of a lipid-based threat-agnostic biosignature.
Success of this project would: 1) demonstrate the utility of lipids as a threat-agnostic biosignature for AMR vs. AMS, 2) incorporate LC-IMS-MS/MS and ozonolysis in the standard PNNL lipidomics pipeline to enable definition of structural features (double bonds, branched chains, etc.) that are largely ignored in the current platform (yet critical biologically), and 3) establish PNNL as a leader in the field of lipid structural definition as another dimension to our reputation for world-class mass spectrometry. This project will also generate data that can be used to establish a predictive model to understand the ozone fragmentation spectra and the ability of the approach to differentiate AMR and AMS based on lipid signatures.
Project Details
Start Date
2021-01-18
End Date
2023-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members