A brain-to-lung signal controls pulmonary inflammatory responses

Immune cells in the lungs are considered a heterogeneous population in the context of pneumonia. We used single-cell RNA sequencing (scRNA-seq) to analyze the diversity of immune cells in the lungs under different severities of pneumonia. Additionally, we employed bulk RNA sequencing (bulk RNA-seq) to study the transcriptional changes of sorted macrophage subsets in the lungs after NE(Norepinephrine), LPS, and NE+LPS stimulation. Overall design: In this study, the samples were categorized into 'sham', 'mild', and 'severe' groups to reflect different severities of pneumonia in the mouse model. Specifically, 'sham' refers to the control group with no pneumonia, 'mild' represents mice with mild pneumonia symptoms, and 'severe' indicates mice with severe pneumonia symptoms. Pulmonary immune cells from these different severity groups were isolated using Fluorescence-activated cell sorting (FACS), based on the presence or absence of CD45, and analyzed using single-cell RNA sequencing (scRNA-seq). For bulk RNA-seq, the sorted macrophages were divided into four groups: the control group, which received no treatment; the LPS-only group, which was treated with LPS for 3 hours; the Norepinephrine (NE)-only group, which was treated with Norepinephrine for 3 hours; and the final group, which was pretreated with Norepinephrine for 3 hours and subsequently treated with LPS for 3 hours.