Transcriptional profiling of CD44hi AT2 cells under homeostasis and after lung injury [II]

The epithelium of alveoli is composed of alveoli type I cells (AT1) that cover ~95% of the surface area and alveoli type II cells (AT2) that secret surfactant as well as function as adult stem cells. CD44hi subpopulation of AT2 cells exhibits higher potential to proliferate and differentiate under steady state conditions. To understand the CD44hi subpopulation of AT2 cells after lung injury, we assessed those cells in a Pseudomonas aeruginosa (PA) induced mouse model of lung injury. CD44hi and CD44low AT2 cells were FACS sorted from untreated and 3d PA treated mice. In addition, since Sca1+ AT2 cells were shown to emerge during the repair phase of the PA induced injury in our earlier studies, we also isolated Sca1+ AT2 cells at 3d post PA injury to compare with the CD44hi subpopulation. RNA-seq was used to compare the expression profile of the different subgroups of AT2 cells. Overall design: The goal of this study was to (1) compare the gene expression profiles of CD44hi AT2 cells under steady-state conditions and after lung injury and (2) compare the gene expression profile of CD44hi, CD44low, and Sca1+ AT2 cells after lung injury. Total RNA profiles were generated by deep sequencing using Illumina HiSeq4000.