Single-cell Transcriptome analysis reveals cellular heterogeneity and highlights Fstl1-regulated alveolar myofibroblasts in mouse lung at birth
The matricellular protein follistatin-like 1 (FSTL1) regulates lung development and saccular formation. Here, we employed single-cell RNA sequencing (scRNA-seq) to construct a transcriptomic atlas of 22,774 individual cells in wild-type (WT) and Fstl1–/– lung (E18.5) samples and identified 27 cell subtypes. We reveal abnormal population sizes and gene expression profiles in diverse cell subtypes in Fstl1–/– lung samples. We identify Pdgfra and Tgfbi as genetic markers specifically expressed in postnatal myofibroblasts (MyoFBs). Fstl1 deletion decreases the number of MyoFB cells and downregulates their roles in ECM organization and muscle tissue/vasculature development, in part, through the TGF-ß1/BMP4 signaling pathway. Our data provide a single-cell view of the cellular heterogeneity and the molecular mechanisms underlying abnormal saccular formation and atelectatic lungs in Fstl1–/– mice. Overall design: sc-RNA seq analysis of WT and Fstl1–/– lung mice at birth.