Single-cell RNA sequencing analysis of lung tissue profiles of mice undergoing hepatic ischemia-reperfusion. Mus musculus

Ischemia-reperfusion(IR) injury is an unavoidable complication during liver transplantation(LT). Acute lung injury (ALI) is the main factor that primarily affects patient survival and post-transplant morbidity and mortality, as the susceptibility of the lungs to reperfusion injury increases significantly during the transplantation process.To assess the phenotype and plasticity of various cell types in the lung tissue microenvironment after hepatic ischemia-reperfusion(HIR) at the single-cell level, we performed single-cell RNA sequencing (scRNA-Seq) using lungs from mice receiving HIR.We identified 23 different cell types in the lung after HIR and found that this highly complex ecosystem is formed by subpopulations of bone marrow-derived cells that signal to each other and mediate inflammatory responses in different states and at different intervals. Notably, we identified two novel subpopulations with a pro-inflammatory phenotype, EC3, and Neu2, in the HIR group that mediated ALI. We also detected two classes of T cells with distinct cellular functions that mediate more severe ALI through HIR, a CD8+ T cell subpopulation that activates Mon2-CD16 through the CD40LG/CD40 axis and a CD9+ T cell subpopulation that is highly associated with endothelial cells. In addition, we identified possible pathways of action of S100a8 and S100a9 genes in this model.We revealed a cellular landscape of lung tissue after HIR, highlighting the heterogeneity and cellular interactions between major immune cells. These observations provide new insights into the mechanisms of ALI due to HIR and offer new therapeutic strategies to improve post-transplant lung injury.

缺血再灌注（Ischemia-reperfusion, IR）损伤是肝移植（liver transplantation, LT）过程中无法避免的并发症。急性肺损伤（acute lung injury, ALI）是影响患者术后生存及移植后发病率与死亡率的主要因素，因移植过程中肺脏对再灌注损伤的易感性显著升高。为在单细胞层面解析肝缺血再灌注（hepatic ischemia-reperfusion, HIR）后肺组织微环境中各类细胞的表型与可塑性，我们对接受HIR造模的小鼠肺部组织开展了单细胞RNA测序（single-cell RNA sequencing, scRNA-Seq）。我们在HIR术后的肺脏中鉴定出23种不同的细胞类型，并发现这一高度复杂的生态系统由骨髓来源细胞亚群构成，这些亚群可相互传递信号，并在不同状态与时段介导炎症反应。值得注意的是，我们在HIR组中鉴定出两个具有促炎表型的新型细胞亚群——EC3与Neu2，二者可介导ALI。我们还检测到两类具有独特细胞功能的T细胞亚群，它们可通过HIR加剧ALI：一类是通过CD40LG/CD40轴激活Mon2-CD16的CD8阳性T细胞亚群，另一类是与内皮细胞高度相关的CD9阳性T细胞亚群。此外，我们在该模型中阐明了S100a8与S100a9基因的潜在作用通路。我们绘制了HIR术后肺组织的细胞图谱，着重揭示了主要免疫细胞间的异质性与细胞互作关系。上述研究结果为HIR诱导的ALI发病机制提供了新的见解，并为改善移植后肺损伤提供了全新的治疗策略。