A consistent body of research has linked cystic fibrosis (CF) with variations in the tissue and fluid content in a number of lipid molecules. However, little is known about the spatial localization of those variations. We have recently applied TOF-
SIMS mass spectrometry imaging to detect differential lipid signatures at the colon epithelium between normal and cftr−/− mice. In the present work we have used this technology to investigate potential differences in the spatial distribution of lipids due to
Pseudomonas aeruginosa (
P.a.) infection in mouse lung expressing or not cftr. Wild-type and exon 10 cftr knockout mice were subjected to intranasal infection with a clinical strain of
P.a. Lung cryosections from infected and non-infected mice were subjected to cluster TOF-SIMS analysis in the negative ion mode. We observed a highly specific localization of a phosphoinositol fragment ion at
m/
z 299.1 in bronchial epithelium. Using this ion to delineate a region of interest, we studied the relative abundance of ions below
m/
z 1500. We found a significant increase in
m/
z 465.4 (identified as cholesteryl sulfate) in cftr−/− epithelium and in response to bacterial infection, as well as a decrease in most carboxylic ions. In conclusion, the
m/
z 299.1 ion can be used as a marker of bronchial epithelium, where
P.a. infection leads to increased presence of cholesteryl sulfate in this tissue. TOF-SIMS imaging reveals as a valuable tool for the study of respiratory epithelium.
This article is part of a Directed Issue entitled: Cystic Fibrosis: From o-mics to cell biology, physiology, and therapeutic advances.