Single-cell transcriptomic analysis links non-myelinating Schwann cells to pro-inflammatory response in the lung [scRNA-seq]

The lung is a barrier tissue with constant exposure to the inhaled environment. Therefore, innate immunity against particulates and pathogens is of critical importance to maintain tissue homeostasis. While the lung harbors both myelinating and non-myelinating Schwann cells (NMSCs), NMSCs represent the abundant Schwann cell (SC) population in the lung. However, their contribution to lung physiology remains largely unknown. Here, we used the human glial fibrillary acidic protein promoter (GFAP) driving tdTomato expression in mice to identify SCs in the peripheral nervous system (PNS) and determine their location within the lung. Single-cell transcriptomic analysis revealed the existence of two NMSC populations (NMSC1 and NMSC2) that may participate in pathogen recognition. We demonstrated that these pulmonary SCs produce chemokines and cytokines upon lipopolysaccharide (LPS) stimulation using in vitro conditions. Furthermore, we challenged mouse lungs with LPS and found that NMSC1 exhibits an enriched pro-inflammatory response among all SC subtypes. Collectively, these findings define the molecular profiles of lung SCs and suggest a potential role for NMSCs in lung inflammation. Overall design: hGFAP-tdTomato mice were either untreated or treated with PBS (vehicle) or LPS for 2 hours via oropharyngeal aspiration route (3 replicates per treatment condition). Then SCs were sorted using Fluorescence activated cell sorting (FACS) by selecting for CD45-EPCAM-CD31-tdTomato high cells from lung tissues, and analyzed by single-cell RNA-seq.