Effects of TNFR1 deletion in mice in early life

Athough anti-TNF therapies can be used to treat colitis associated with inflammatory bowel disease, in mice the loss of the TNF receptor TNFR1 (Tnfrsf1a) in the Il10-/- spontaneous colitis background results in acceleration of disease onset. Whereas Il10-/- mice on the Bl/6 background are relatively protected from colitis throughout life, Il10-/- Tnfr1-/- mice develop colitis beginning at 4 wks of age. Their disease results in nearly 50% mortality by 12 wks of age. Strikingly, Tnfr1-/- mice (with functional IL-10) exhibit evidence of mucosal dysfunction at 4 and 12 wks of age. These mucosal abnormalities include loss of barrier integrity, increased epithelial cell proliferation, crypt malformations, and increased immune cell infiltrate. Because of the early onset of mucosal abnormalities in Tnfr1-/- mice, with or without IL-10 expression, we hypothesized that TNFR1 plays important roles in colonic mucosal function in early life, prior to weaning. To test this hypothesis, we profiled, using mRNA-Seq, the colonic transcriptomes from wildtype and Tnfr1-/- mice at 2 wks of age. The results demonstrate that Tnfr1-/- mice have important gene expression changes, including reduced expression of Il1b, a marker of the proinflammatory "weaning reaction" that is required for establishment of mucosal tolerance in later life. TNFR1 therefore has key roles in colonic mucosal homeostasis in early life. Overall design: A total of 11 samples were analyzed. Each sample is composed of total RNA isolated from the full-thickness colon of a 2-wk-old mice. Five wildtype (WT) and six Tnfr1-/- mice were profiled.