Single-cell RNA Sequencing of Pig Lung Transplantation Reveals Macrophage Ferroptosis in Lung Ischemia?Reperfusion Injury

Primary graft dysfunction (PGD), which is caused primarily by ischemia–reperfusion injury (IRI), is a major obstacle in lung transplantation. Here, we developed an orthotopic, single-lung transplant pig model to simulate prolonged cold IRI. After 24 hours of cold ischemia and 8 hours of warm reperfusion, the transplanted lung exhibited severe allograft injury. Subsequent single-cell RNA sequencing (scRNA-seq) revealed significant changes in alveolar macrophages after IRI, with prominently enriched ferroptosis pathways. Transmission electron microscopy (TEM) confirmed characteristic ferroptosis changes in lung macrophages, and decreased GPX4 expression in macrophages indicated increased susceptibility to ferroptosis. Overall, our pig orthotopic left lung transplant model effectively simulates IRI after transplantation, which offers a valuable platform for more detailed investigations of early reperfusion injury to pulmonary grafts. Moreover, we preliminarily demonstrated the importance of macrophage ferroptosis in IRI, suggesting that inhibiting macrophage ferroptosis may be a promising therapeutic strategy for lung IRI. Overall design: Here, we developed an orthotopic, single-lung transplant pig model to simulate prolonged cold IRI. After 24 hours of cold ischemia and 8 hours of warm reperfusion, the transplanted lung exhibited severe allograft injury. To further investigate the pathological changes associated with lung IRI, we performed scRNA-seq of CD45+ cells (n=2) and CD45- cells (n=1) generated from allograft tissues, and total cell suspensions isolated from right donor lung tissues (n=3).