“…In the lungs, pulmonary neuroendocrine cells (PNECs) are thought to be exclusively localized to surface epithelia where they are sparsely distributed or clustered at distal airway branch points ( Branchfield et al, 2016 ; Cho et al, 1989 ; Hogan et al, 2014 ; Kuo and Krasnow, 2015 ). They are chemosensory cells that respond to odorants, oxygen, mechanical stimuli, and allergens by releasing neurotransmitters and neuropeptides ( Cutz and Jackson, 1999 ; Gu et al, 2014 ; Lembrechts et al, 2012 ; Noguchi et al, 2020 ; Whitsett and Morrisey, 2016 ; Xu et al, 2020 ), which signal either parasympathetic afferents ( Chang et al, 2015 ; Liu et al, 2021 ; Su et al, 2022 ) or local immune and epithelial cells ( Branchfield et al, 2016 ; Sui et al, 2018 ; Xu et al, 2022 ). As examples, PNECs respond to allergens and hypoxia by stimulating mucus cell production and tissue repair by the airway surface epithelium ( Shivaraju et al, 2021 ; Sui et al, 2018 ).…”