GSE126205
PDGFRa and aSMA mark two distinct mesenchymal cell populations involved in parenchymal and vascular remodeling in pulmonary fibrosis
We utilized a fate-mapping approach to investigate alpha-smooth muscle actin (aSMA)+ and platelet derived growth factor-alpha (PDGFRa)+ cells in two lung fibrosis models, complemented by cell-type specific next-generation sequencing and investigations on human lungs. Our data revealed that aSMA+ and PDGFRa+ cells mark two distinct mesenchymal lineages with minimal transdifferention potential during lung fibrotic remodeling. Parenchymal and perivascular fibrotic regions were populated predominantly with PDGFRa+ cells expressing collagen, while aSMA+ cells in the parenchyma and vessel wall showed  variable expression of collagen and the contractile protein desmin. The distinct gene expression profiles found in normal conditions was retained during pathologic remodeling. Cumulatively, our findings identify aSMA+ and PDGFRa+ cells as two separate lineages with distinct gene expression profile in adult lungs. Overall design: Pdgfra- or Acta2-CreERT2; tdTomatoflox  reporte mice were treated with saline or bleomycin (n=4/group). A single cell suspension was made from the lung and tdTomato-positive cells were sorted directly into RNA lysis buffer (Qiagen, Venlo, Netherlands) using a FACSAria II cell sorter (BD Biosciences, San Jose, CA, USA). RNA was isolated with the RNeasy micro kit (Qiagen). Library preparation using the SmartSeq2 protocol and sequencing on the Illumina HiSeq 3000 platform was done by the Biomedical Sequencing Facility, CeMM, Vienna. NGS reads were aligned with the TopHat2 (v2.1.1) (Kim et al., 2013) splice junction mapper using the Bowtie2 short read aligner (v2.2.9) (Langmead and Salzberg, 2012). Transcriptome assembly and differential expressing calling was performed with Cufflinks (v2.1.1) (Trapnell et al., 2013).  cells fromt he lungs were enzymatically isolated.