Lingo3 interacts with TFF2 to control mucosal integrity, Type 1 inflammation, and colitic tissue repair

Abstract

Constant exposure of intestinal epithelial cells (IEC) to potentially damaging stimuli makes mucosal repair programs essential for gut homeostasis, immunological quiescence and resistance to colitis. Trefoil factor 2 (TFF2) is a mucus associated protein that promotes epithelial barrier integrity in the lung and intestine, but whether a bona-fide TFF2 receptor exists remains controversial. Herein, we provide evidence that leucine rich repeat nogo interacting protein 3 (LINGO3) is a transmembrane component of TFF2 signaling and proliferation within IEC. TFF2 requires LINGO3 for barrier recovery in scratch-wound assays and mice lacking LINGO3 (LINGO3KO) have impaired intestinal barrier function under steady state conditions. Interestingly, LINGO3KO mice phenocopy TFF2KO mice, with both having a significant accumulation of mucosal CD4+TH1 cells expressing IFNg+ TNFa+ under steady-state conditions and impaired recovery from DSS-induced colitis. Impaired recovery in LINGO3KO animals was marked by reduced intestinal crypt regeneration and reduced expression of the stem cell marker LGR5 compared to WT counterparts. Additionally, TFF2 agonist administration (TFF2-Fc) promoted enhanced recovery and limited inflammatory cell recruitment in WT mice during DSS-induced colitis whereas TFF2-Fc treatment was ineffective in LINGO3KO animals. Combined, these data support our contention that a TFF2-LINGO3 ligand/receptor axis regulates tissue repair and inflammation within the gastrointestinal tract through regulation of IEC function.