Spatial lipidomic profile remodeling in neutropenic cystic fibrosis–like lung tissue revealed by IR-MALDESI mass spectrometry imaging

Neutrophil recruitment and abundance in the lungs of people with cystic fibrosis (CF) perpetuates a cycle of chronic pulmonary inflammation. Phospholipids comprise the majority of pulmonary surfactant and, in a disease state such as those in the CF lung, altered phospholipid distribution and abundance implicates metabolic and cellular dysregulation. We explored the impact of neutrophils on the lung lipidomic landscape utilizing the β-ENaC transgenic mouse (as a phenocopy model of the CF lung environment) and infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI). Histology-driven MSI, supported by localization-dependent tissue isolation of epithelial-lined airways and parenchyma, revealed significant lipid remodeling associated with transgenic lungs and neutrophil load. For the first time, IR-MALDESI MSI identified 85 differential lipids and metabolites, including the critical neutrophil recruitment factor Leukotriene B4 (LTB4). Phosphatidylglycerols (PG) and diacylglycerols (DG) were differentially upregulated in β-ENaC tissues, while PAs were downregulated relative to WT tissue. These alterations coincided with significant mucus plugging, supporting the broad remodeling of lung lipid composition that occurs in CF. Notably, induced neutropenia in the transgenic lung shifted or completely restored the β-ENaC lipidomic profiles to the wildtype baseline across both the parenchyma and epithelial-lined airway features. These findings identify the consequences of sodium/chloride transport imbalance and neutrophil loading on spatial lipidomic remodeling in lung tissue.