Macrophage peroxisomes guide alveolar regeneration and limit post-acute sequelae of SARS-CoV-2 infection (PASC)

Peroxisomes are essential but often overlooked metabolic organelles. To explore how macrophage peroxisomes protect the lung, we conducted single-cell RNA sequencing (scRNA-seq) on lungs from both naïve and SARS-CoV-2-infected Pex5^flox/flox (WT) and Cd11c-cre Pex5^flox/flox (KO) mice at 7 days post-infection (d.p.i). scRNA-seq revealed an increased proportion of inflammatory monocytes, neutrophils, and monocyte-derived macrophages (MDMs) in the lungs of infected KO mice, alongside a marked reduction in alveolar type 2 (AT2) cells and alveolar macrophages (AMs) compared to infected WT mice. AMs from KO mice showed elevated expression of genes involved in inflammatory responses, innate immunity, and cellular stress signaling, while genes related to wound healing, cell differentiation, and lipid metabolism were downregulated, compared to AMs from WT mice at 7 d.p.i. Overall design: Cd11c-cre Pex5^flox/flox or Pex5^flox/flox mice were either uninfected (day 0) or infected with 2000 PFU of SARS-CoV-2 MA30 virus. Lung cells were harvested on day 0 and day 7 post infection. For each time point, cells from three individual mice per genotype were pooled and subjected to single-cell RNA sequencing (scRNA-seq) analysis

过氧化物酶体（Peroxisomes）是一类不可或缺却常被忽视的代谢细胞器。为探究巨噬细胞过氧化物酶体对肺部的保护机制，本研究对未感染（naïve）以及感染新型冠状病毒（SARS-CoV-2）后7天的Pex5^flox/flox野生型（wild type, WT）小鼠与Cd11c-cre Pex5^flox/flox敲除型（knockout, KO）小鼠的肺部组织开展了单细胞RNA测序（single-cell RNA sequencing, scRNA-seq）分析。测序结果显示，相较于感染后的野生型小鼠，感染后的敲除型小鼠肺部的炎性单核细胞、中性粒细胞及单核细胞来源的巨噬细胞（monocyte-derived macrophages, MDMs）比例显著升高；与此同时，肺泡II型上皮细胞（alveolar type 2 cells, AT2）与肺泡巨噬细胞（alveolar macrophages, AMs）的比例则明显降低。与感染7天后的野生型小鼠肺泡巨噬细胞相比，敲除型小鼠的肺泡巨噬细胞中，参与炎症反应、固有免疫及细胞应激信号通路的基因表达水平显著上调，而与创伤修复、细胞分化及脂质代谢相关的基因则呈现下调趋势。实验总体设计：将Cd11c-cre Pex5^flox/flox或Pex5^flox/flox小鼠分为未感染组（感染后第0天）与感染组，感染组小鼠接种2000蚀斑形成单位（plaque forming unit, PFU）的SARS-CoV-2 MA30病毒。分别于感染后第0天和第7天收集肺部细胞。每个时间点下，每种基因型的3只个体小鼠的肺部细胞混合后，进行单细胞RNA测序分析。