PNNL

Abstract

Bronchopulmonary dysplasia (BPD) is a neonatal lung disease characterized by inflammation and scarring in the lung leading to long-term tissue damage. Previous whole tissue proteomics have identified BPD-specific proteome changes and cell type shifts. Little is known about the proteome-level changes within specific cell populations in disease. Here, we sorted epithelial (EPI) and endothelial (ENDO) cell populations based on their differential surface markers from normal and BPD human lungs. Using a low-input compatible sample preparation method (MicroPOT), proteins were extracted and digested into peptides and subjected to Liquid chromatography-Mass spectrometry (LC-MS/MS) proteomics analysis. Of the 4,970 proteins detected, 293 were modulated in abundance or detection in the EPI population and 422 were modulated in ENDO cells. Modulation of proteins associated with actin-cytoskeletal function such as SCEL, LMO7 and TBA1B were observed in the BPD EPIs. Using confocal imaging and analysis, we validated the presence of aberrant multilayer-like structures comprising SCEL and LMO7, known to be associated with epidermal cornification, in the human BPD lung. This is the first report of cornification-associated proteins in BPD and their localization in the alveolar parenchyma, primarily associated with Alveolar type I (AT1) cells suggests a role of these structures in the BPD post-injury response. In the ENDOs, modulated pathways comprised redox balance and mitochondrial function. Alternative splicing and proliferative function were elevated in both populations suggesting potential dysregulation of cell progenitor fate. This study, for the first time, characterized the proteome of epithelial and endothelial cells from the BPD lung, identifying population-specific changes in BPD pathogenesis.