Journal Club LIVE: Targeted DESI-MRM MS Imaging for Spatially Mapping Oxylipins in Pulmonary Tissue
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This interactive session will bring together the MS community to discuss some of the most popular and exciting peer-reviewed publications in a friendly and open forum.
Ahead of each meeting, we will send out a link to the discussion article, then during the session an expert will summarise the main findings and answer your questions.
READ THE JOURNAL HERE: Development of a Desorption Electrospray Ionization–Multiple-Reaction-Monitoring Mass Spectrometry (DESI-MRM) Workflow for Spatially Mapping Oxylipins in Pulmonary Tissue
We're proud to be joined by two of the authors, Matt Smith and Craig Wheelock from the Karolina Institute, Sweden where they will discuss their recent study on advancing mass spectrometry imaging for oxylipin research using DESI MRM workflows. This targeted mass spectrometry imaging approach enables spatial mapping of oxylipins directly in lung tissue with enhanced sensitivity.
Key discussion topics include:
- Development of a DESI-MRM workflow for oxylipin detection in pulmonary tissue.
- Selection of a focused oxylipin panel for imaging and spatial analysis.
- Introduction of quantMSImageR, a custom R package for labeling, quantifying, and analyzing lipid distributions.
- Findings showing distinct localization patterns of oxylipins between airways and parenchyma.
FULL ABSTRACT
Oxylipins are a class of low-abundance lipids formed via oxygenation of fatty acids. These compounds include potent signaling molecules (e.g., octadecanoids, eicosanoids) that can exert essential functions in the pathophysiology of inflammatory diseases including asthma. While some oxylipin signaling cascades have been unraveled using LC-MS/MS-based methods, measurements in homogenate samples do not represent the spatial heterogeneity of lipid metabolism.
Mass spectrometry imaging (MSI) directly detects analytes from a surface, which enables spatial mapping of oxylipin biosynthesis and migration within the tissue. MSI has lacked the sensitivity to routinely detect low-abundance oxylipins; however, new multiple-reaction-monitoring (MRM)-based MSI technologies show increased sensitivity.
In this study, we developed a workflow to apply desorption electrospray ionization coupled to a triple quadrupole mass spectrometer (DESI-MRM) to spatially map oxylipins in pulmonary tissue. The targeted MSI workflow screened guinea pig lung extracts using LC-MS/MS to filter oxylipin targets based on their detectability by DESI-MRM. A panel of 5 oxylipins was then selected for DESI-MRM imaging derived from arachidonic acid (TXB2, 11-HETE, 12-HETE), linoleic acid (12,13-DiHOME), and α-linolenic acid (16-HOTrE).
To parse this new data type, a custom-built R package (quantMSImageR) was developed with functionality to label regions of interest as well as quantify and analyze lipid distributions. The spatial distributions quantified by DESI-MRM were supported by LC-MS/MS analysis, with both indicating that 16-HOTrE and 12-HETE were associated with airways, while 12,13-DiHOME and arachidonic acid were mapped to parenchyma. This study realizes the potential of targeted MSI to routinely map low-abundance oxylipins with high specificity at scale.
Presenter: Craig Wheelock (Principal Researcher, Karolinska Institute)
Craig Wheelock an Associate Professor of Biochemistry and Head of the Unit of Integrative Metabolomics in the Institute of Environmental Medicine at the Karolinska Institute (KI), Stockholm, Sweden.
He serves as Director of the Integrative Molecular Phenotyping Laboratory and the small molecule mass spectrometry core facility (KI-SMMS). He is also a Distinguished Visiting Professor of Metabolomics at Nagoya City University, Japan. Professor Wheelock received his doctorate at the University of California Davis in 2002 and conducted post-doctoral studies at Kyoto University, Japan.
Presenter: Dr Matt Smith (Postdoctoral Researcher, Karolinska Institute)
Matt Smith is a postdoctoral researcher using targeted liquid chromatography and imaging mass spectrometry approaches to understand the role of lipid mediators in the onset and resolution of inflammation.
