The RNA-binding protein Imp1 promotes a Spdef transcriptional program and mucus fucosylation during necrotizing...

Necrotizing enterocolitis (NEC) is the most deadly gastrointestinal disease in preterm neonates, with up to 50% mortality. There is no cure for NEC. Enhancing our understanding of intestinal epithelial cell (IEC) responses to NEC will provide novel therapeutic targets. The RNA-binding protein insulin-like growth factor 2 mRNA binding protein 1 (IMP1) plays roles in intestinal development and repair. Notably, roles for IMP1 in NEC are unknown. Intestinal goblet cells produce protective mucus, and their function depends on the transcription factor SAM pointed domain containing ETS transcription factor (SPDEF). Evidence suggests that goblet cell mucus glycosylation affects barrier function and inflammation. We aimed to define the role of IMP1 in NEC damage response using neonatal human enteroids and an NEC-like intestinal injury model. At postnatal day 3, wild-type mice or littermates with IEC-specific IMP1 overexpression (Imp1^IEC-OE) or loss (Imp1^ΔIEC) were assigned to control or NEC groups. NEC was induced with stress, formula feeding, bacterial exposure, and hypoxia. IMP1 effects on NEC response were assessed using RNA sequencing, Western blotting, immunostaining, and a cytokine array. We found that proinflammatory bacteria induced IMP1 expression in neonatal human enteroids. During NEC, Imp1^IEC-OE mice exhibit more severe intestinal damage and priming for lytic cell death. Elevated IMP1 levels were linked to a SPDEF transcriptional signature and in silico analysis predicted IMP1 binding to Spdef and mucus glycosylation mediator mRNAs. Functionally, IMP1 increased fucosylation in the intestinal epithelium. Collectively, results suggest that IMP1 primes the intestine for lytic death and promotes the production of fucosylated mucus, changes which could alter the damage response.NEW & NOTEWORTHY Expression of the RNA-binding protein IMP1 is enhanced in neonatal human enteroids in response to NEC-associated enteric bacteria. IMP1 regulates goblet cell function in response to early intestinal inflammation in a mouse model of necrotizing enterocolitis. IMP1 enhances epithelial damage and priming for lytic cell death, while promoting a SPDEF transcriptional program through SPDEF upregulation and elevated expression of SPDEF target genes. In addition, IMP1 increases the gene expression of α(1, 2)fucosyltransferase, Fut2, and increases UEAI-positive cells.