Effect of colonic epithelial knockout of tumor necrosis factor receptor 2 (TNFR2) in dextran sulfate sodium (DSS)-induced colitis
Colonic epithelial repair is a key determinant of health. After injury, repair initiates through phenotypic reprogramming of wounded epithelium to a regenerative state permissive for the activation of alternative stem cell populations and healing. Although cytokine signals such as interferons may help induce regenerative reprogramming, the signals that modify this state as the wound resolves remain largely unknown. Here we examined whether cytokine signaling mediated by tumor necrosis factor receptor 2 (TNFR2) influenced the wound repair process. We examined mice with targeted deletion of the Tnfrsf1b (TNFR2) gene in intestinal/colonic epithelium (Vil1::Cre;Tnfr2-f/f) and compared their transcriptional profiles to control (Tnfr2-f/f) mice. We sorted EpCAM+ (epithelial) cells from Vil1::Cre;Tnfr2-f/f and control DSS-treated mice and performed bulk RNA-Seq. Comparison of transcript expression profile before and after DSS-induced colitis in control (Tnfr2-f/f) mice revealed upregulation of pathways associated with metabolic regulation, ribosomal function, oxidative stress, TNF signaling, and focal adhesions after DSS treatment. Pathway enrichment analysis demonstrated elevated regenerative (“fetal”) intestinal signaling, reduced inflammation, and increased proliferative signaling in Vil1::Cre;Tnfr2-f/f colonic epithelium after DSS treatment. The knockout epithelium also showed reduced expression of markers of differentiated colonic epithelium and elevated expression of progenitor cell signaling. Thus, the transcriptional data were consistent with increased regenerative signaling in TNFR2-knockout epithelium, suggesting that TNFR2 has a role in restraining the relatively undifferentiated regenerative state. Overall design: Comparison of distal colonic epithelial gene expression across conditions of health and DSS-induced colitis, in wildtype mice and in mice with epithelial-targeted knockout of TNFR2