A brain-to-lung signal from GABAergic neurons to ADRB2+ interstitial macrophages promotes pulmonary inflammatory responses

interstitial macrophages surrounding the pulmonary sympathetic nerves (PSNs) responded to elevated NE, which aggravated inflammation and lung injury during severe pneumonia. Specific inhibition of PSNs and ADRB2 signaling improved the outcomes of severe pneumonia. Our study identifies a crucial brain-to-lung sympathetic signal controlling macrophage-mediated lung inflammatory responses, which could be harnessed as a therapeutic strategy for severe pneumonia.