The level of microRNA (miR)‐431 was found to be markedly up‐regulated in intestinal tissue of necrotizing enterocolitis (NEC). The objective of this study was to identify the target gene of miR‐431 and to investigate the role of the miR‐431‐FOXA1 axis in the pathophysiology of NEC. The target gene of miR‐431 was identified by in silico target prediction bioinformatics, luciferase assay, and Western blotting. Effects of miR‐431 on downstream expression signals, cell proliferation, and apoptosis were investigated by overexpression in Caco‐2 cells upon stimulation by LPS or lipoteichoic acid (LTA). FOXA1 was identified as the target gene of miR‐431. Overexpression of miR‐431 in Caco‐2 cells significantly inhibited FOXA1, ESRRG, and HNF4A and activated IL‐6, LGR5, NFKB2, PLA2G2A, PRKCZ, and TNF. IL‐8 and ‐10 were enhanced when costimulated with LPS or LTA. These potential downstream genes were also significantly dysregulated in primary NEC tissues compared with surgical‐control tissues. Overexpression of miR‐431 significantly decreased proliferation and increased apoptosis of Caco‐2 cells. A proposed network of miR‐431‐FOXA1 interaction with LPS and LTA receptors demonstrates dysregulation of transcription factors, inflammatory mediators, epithelium tight junction regulators, and cell proliferation and apoptosis signals. The miR‐431‐FOXA1 axis could in part be responsible for the intensification of the inflammatory response in NEC tissues and contribute to the proinflammatory pathophysiology.—Wu, Y. Z., Chan, K. Y. Y., Leung, K. T., Lam, H. S., Tam, Y. H., Lee, K. H., Li, K., Ng, P. C. Dysregulation of miR‐431 and target gene FOXA1 in intestinal tissues of infants with necrotizing enterocolitis. FASEB J. 33, 5143–5152 (2019). http://www.fasebj.org

We previously demonstrated that microRNA(miR)‐223 is overexpressed in intestinal tissue of infants with necrotizing enterocolitis (NEC). The objective of the current study was to identify the target gene of miR‐223 and to investigate the role of the miR‐223/nuclear factor I‐A (NFIA) axis in cellular functions that underpin the pathophysiology of NEC. The target gene of miR‐223 was identified by in silico target prediction bioinformatics, luciferase assay, and western blotting. We investigated downstream signals of miR‐223 and cellular functions by overexpressing the miRNA in Caco‐2 and FHs74 cells stimulated with lipopolysaccharide or lipoteichoic acid (LTA). NFIA was identified as a target gene of miR‐223. Overexpression of miR‐223 significantly induced MYOM1 and inhibited NFIA and RGN in Caco‐2 cells, while costimulation with LTA decreased expression of GNA11, MYLK, and PRKCZ. Expression levels of GNA11, MYLK, IL‐6, and IL‐8 were increased, and levels of NFIA and RGN were decreased in FHs74 cells. These potential downstream genes were significantly correlated with levels of miR‐223 or NFIA in primary NEC tissues. Overexpression of miR‐223 significantly increased apoptosis of Caco‐2 and FHs74 cells, while proliferation of FHs74 was inhibited. These results suggest that upon binding with NFIA, miR‐223 regulates functional effectors in pathways of apoptosis, cell proliferation, G protein signaling, inflammation, and smooth muscle contraction. The miR‐223/NFIA axis may play an important role in the pathophysiology of NEC by enhancing inflammation and tissue damage.