Lipid metabolism-related genes regulate the immune microenvironment during ex vivo lung perfusion for lung transplants.

BACKGROUND: Ex vivo lung perfusion (EVLP) serves as a vital platform for donor lung assessment and repair in transplantation. Although lipid metabolism plays a crucial role in pulmonary homeostasis and undergoes alterations during EVLP, the precise regulatory mechanisms linking metabolic changes to immune modulation remain poorly understood. This study aimed to identify key lipid metabolism-related genes governing immune microenvironment remodeling during EVLP and to validate their diagnostic and therapeutic potential. METHODS: We analyzed transcriptomic profiles from human donor lungs before and after EVLP using datasets GSE127057 (discovery cohort) and GSE127055 (validation cohort). A comprehensive analytical framework was implemented, incorporating weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI) networks, and three machine learning algorithms including least absolute shrinkage and selection operator (LASSO) regression, Random Forest (RF), and eXtreme Gradient Boosting (XGBoost) to identify key lipid metabolism-related genes. Immune cell infiltration patterns were characterized using established computational methods, with subsequent validation in an EVLP model of C57BL/6J wild-type mice. RESULTS: Analysis of GSE127057 revealed 656 differentially expressed genes (DEGs) post-EVLP. Through integrative bioinformatics approaches, three lipid metabolism-related hub genes (UGCG, SAMD8, MED26) were identified as consistently upregulated. These genes demonstrated significant positive correlations with resting natural killer (NK) cell populations and negative associations with activated NK cells. The diagnostic potential of these biomarkers was confirmed through receiver operating characteristic (ROC) analysis, achieving an area under curve (AUC) of 0.986 in the discovery cohort (GSE127057) and 0.922 in the independent validation cohort (GSE127055). Experimental validation in murine EVLP models recapitulated the significant upregulation of all three hub genes. CONCLUSIONS: This study establishes UGCG, SAMD8, and MED26 as central regulators of lipid metabolism during EVLP, with their expression patterns correlating with NK cell functional states. These findings provide mechanistic insights into metabolic-immune interactions during donor lung preservation and identify potential biomarkers for clinical monitoring and therapeutic targeting.