Foxo1 regulates intestinal tissue-resident memory CD8 T cell biology in an anatomic compartment- and context-specific manner
Transcriptional regulation of diverse aspects of tissue-resident CD8 memory T cells (TRM) biology is nuanced and context-specific. Transcription factors (TF) that orchestrate TRM formation and maintenance are distinct between anatomic compartments, and predicting the roles of TF on TRM biology is challenging. Here, we applied the Taiji algorithm to map TF networks and identify Forkhead Box protein 01 (Foxo1) as differentially invested in intestinal TRM TF networks. Loss of Foxo1 in established TRM resulted in a survival advantage for small intestinal intraepithelial layer (siIEL) TRM compared with other intestinal compartments. SiIEL TRM were uniquely able to maintain expression of proliferative and anti-apoptotic cellular programs in the absence of Foxo1. This advantage was lost upon blockade of integrin aE (Itgae/CD103). These findings suggest that the TF networks maintaining siIEL TRM exhibit redundancy and highlight an underappreciated role of integrin signaling in TRM biology outside of tissue-retention. Overall design: P14 WT CD45.1 and P14 Foxo1f/f Cre-ERT2+/- CD45.1.2 CD8 T cells were adoptively co-transferred into congenically distinct recipient mice. The recipient mice were infected with 2x105 plaque forming units of lymphocytic choriomeningitis virus 30 minutes after transfer. 21 days post-infection, mice were treated with 0.5mg/g tamoxifen intraperitoneally daily for 5 days, and then sacrificed 2 weeks later. CD8 T cells were isolated from spleen, small intestines, and colon, and incubated in an antibody cocktail containing antibody-derived tags against cell surface markers and fluorescence-conjugated antibodies. The congenically distinct CD8 T cells were separated by fluorescence-activated cell sorting. About 20,000 cells for spleen, siIEL, and siLPL samples were loaded onto Chromium Next GEM Chip M (10x Genomics) and 2,000 cells for cIEL and cLPL were loaded onto Chromium Next Gem Chip G (10x Genomics), and partitioned into Gel Beads. CITE-seq was then performed using previously described protocol (Stoeckius et al., 2017).