Lipid mediators are important in lung biochemistry and are derived from the enzymatic oxidation of arachidonic and docosahexaenoic acids, which are polyunsaturated fatty acids (PUFA) that are present in phospholipids in cell membranes. In this study, matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was used to determine the localization of arachidonate- and docosahexaenoate-containing phospholipids in mouse lung. These PUFA-containing phospholipids were determined to be uniquely abundant at the lining of small and large airways, which were unequivocally identified by immunohistochemistry. In addition, it was found that the blood vessels present in the lung were characterized by sphingomyelin molecular species and lung surfactant phospholipids appeared evenly distributed throughout the lung parenchyma, indicating alveolar localization. This technique revealed unexpected high concentrations of arachidonate- and docosahexaenoate-containing phospholipids lining the airways in pulmonary tissue, which could serve as precursors of lipid mediators affecting airways biology.
The full article is published online in the Journal of Lipid Research and is free to access.