Identification of Different Proteins Binding to Na, K-ATPase α1 in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome Cell Model by Proteomic Analysis

Abstract Acute respiratory distress syndrome (ARDS) is characterized by refractory hypoxemia caused by accumulation of pulmonary fluid, which is related to inflammatory cell infiltration, impaired tight junction of pulmonary epithelium and impaired Na, K-ATPase function, especially Na, K-ATPase α1 subunit. Up until now, the pathogenic mechanism at the level of protein during lipopolysaccharide- (LPS-) induced ARDS remains unclear. Using an unbiased, discovery and quantitative proteomic approach, the discovery of differentially expressed proteins binding to Na, K-ATPase α1 between LPS-induced A549 cell and control-A549 group is of particular interest for the current study. These proteins may help the clinical diagnosis and facilitate the personalized treatment of ARDS. We screened these Na, K-ATPase α1 interacting proteins, carried out the related Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and found evident phenomena of ubiquitination and deubiquitination, as well as the pathways related to autophagy. We also chose some of the differentiated expressing proteins with significant performance for further verification by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among proteins with rich abundance, there were several intriguing ones, including the deubiquitinase (OTUB1), the tight junction protein zonula occludens-1 (ZO-1), the scaffold protein in CUL4B-RING ubiquitin ligase (CRL4B) complexes (CUL4B) and the autophagy-related protein sequestosome-1 (SQSTM1). Protein-protein interaction network showed that there were 244 significantly enriched co-expression among 60 proteins in the group control-A549. while the group LPS-A549 showed 43 significant enriched interactions among 29 proteins. In conclusion, our quantitative discovery-based proteomic approach identified commonalities, and revealed targets related to the occurrence and development of ARDS, being the first study to investigate significant differences in Na, K-ATPase α1 interacting proteins between LPS-induced ARDS cell model and control-A549 cell.