library_construction_protocol: Single-cell suspensions were obtained by first removing whole lung tissues from healthy mice and day 1 post irradiation mice. The tissues were cleaned with cold phosphate-buffered saline, cut into small pieces with lengths of approximately 2 mm, and separated according to the manufacturer's instructions using the Lung Dissociation Kit (mouse) and GentleMACS Dissociator (Miltenyi Biotec, Germany). Next, the lung tissue mixtures were filtered through a 40-µm cell sieve on ice, centrifuged at 4 °C, and washed twice with regular medium to remove incompletely digested fragments and tissues. Single-cell suspensions were converted to barcoded scRNA-seq libraries by using the Chromium Single Cell 3' Library, Gel Bead & Multiplex Kit and Chip Kit (10x Genomics), aiming for an estimated 5,000 cells per library and following the manufacturer's instructions. The generated scRNA-seq libraries were sequenced on an Illumina HiSeq 3000 sequencer.