An amphiregulin reporter mouse enables transcriptional and clonal expansion analysis of reparative lung Treg cells [RNA-Seq]

Treg cells play critical roles in tissue repair processes, certain of which are mediated by production of the growth factor amphiregulin (Areg). We developed a knock-in mouse model for detection of Areg production in live Treg cells, inserting a Thy1a (Thy1.1) construct into the endogenous Areg locus, such that for every transcript of Areg that is translated, a Thy1.1 transcript is also translated and trafficked separately to the cell surface. We used this mouse model to sort for Thy1.1- or Thy1.1+ (Areg-producing or -non-producing) lung Treg cells in models of lung damage (influenza A virus infection and bleomycin acute lung injury), and used them for assessment of gene expression and clonal expansion of these populations. Overall design: AregThy1.1/Thy1.1 mice were administered influenza A virus (IAV) (275 TCID50) or bleomycin (1 mg/kg). At 8 days post-instillation (dpi) (IAV) or 12 dpi (bleomycin), lung Treg cells were sorted for Thy1.1- (Areg-non-producing) and Thy1.1+ (Areg-producing) populations, then sorted populations were lysed for total mRNA for bulk RNA-seq.