Interleukin-22 (IL-22) regulates B3GNT7 expression to induce intestinal fucosylation of O-linked glycans

Interleukin (IL) - 22 is a cytokine that plays a critical role in the maintenance of intestinal epithelial homeostasis. Its downstream functions are mediated through ligation of its heterodimeric receptor comprised of IL-22 receptor subunit alpha 1 (IL-22Ra1) and IL-10R2, and subsequent activation of signal transducer and activator of transcription 3 (STAT3). IL-22 signaling can induce genes necessary for intestinal epithelial cell proliferation, tissue regeneration, tight junction fortification, and production of antimicrobials. Emerging studies have also implicated IL-22 signaling in the regulation of intestinal epithelial fucosylation in mice. However, whether IL-22 regulates intestinal fucosylation in human intestinal epithelial cells and the molecular mechanisms that govern this process are unknown. Here, we show that IL-22 signaling regulates expression of the B3GNT7 transcript, which encodes a ß1-3-N-acetylglucosaminyltransferase that can participate in the synthesis of poly-N-acetyllactosamine (LacNAc) chains. Additionally, we show that IL-22 signaling regulates levels of the a1-3-fucosylated Lewis X (Lex) blood group antigen and this glycan epitope is primarily displayed on heavily O-glycosylated intestinal epithelial glycoproteins. The IL-22-mediated increase in Lex antigen levels requires B3GNT7, as disruption of B3GNT7 expression moderated the IL-22-dependent increase in Lex antigen levels. Moreover, we show that increased expression of B3GNT7 alone is sufficient to promote increased display of Lex-decorated carbohydrate glycan structures primarily on O-glycosylated intestinal epithelial glycoproteins. Together, the data presented here identify B3GNT7 as a critical intermediary in IL-22-dependent induction of intestinal fucosylation of O-linked glycans and uncover a novel role for B3GNT7 in intestinal glycosylation. Overall design: Differentiated Caco-2 BBe1 cells were treated with 10 ng/mL rhIL-22 for 4 h and RNA was isolated for RNA-seq analysis. A no treatment control was used for comparision. Six samples were analyized, which included three biological replicates for each group (no treatment versus IL-22 treated group.