title: Interleukin-23 Increases Intestinal Epithelial Cell Permeability In Vitro.
abstract: Background Breast milk has a heterogeneous composition that differs between mothers and changes throughout the first weeks after birth. The proinflammatory cytokine IL-23 has a highly variable expression in human breast milk. We hypothesize that IL-23 found in human breast milk is biologically active and promotes epithelial barrier dysfunction. Methods The immature rat small intestinal epithelial cell line, IEC-18, was grown on cell inserts or standard cell culture plates. Confluent cultures were exposed to human breast milk with high or low levels of IL-23 and barrier function was measured using a flux of fluorescein isothiocyanate-dextran (FD-70). In addition, protein and mRNA expression of occludin and ZO-1 were measured and immunofluorescence used to stain occludin and ZO-1. Results Exposure to breast milk with high levels of IL-23 caused an increase flux of FD-70 compared with both controls and breast milk with low levels of IL-23. The protein expression of ZO-1 but not occludin was decreased by exposure to high levels of IL-23. These results correlate with immunofluorescent staining of ZO-1 and occludin which show decreased staining of occludin in both the groups exposed to breast milk with high and low IL-23. Conversely, cells exposed to high IL-23 breast milk had little peripheral staining of ZO-1 compared with controls and low IL-23 breast milk. Conclusion IL-23 in human breast milk is biologically active and negatively affects the barrier function of intestinal epithelial cells through the degradation of tight junction proteins.
authors.affiliation: Division of Pediatric Surgery, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Heinzerling
authors.affiliation: Division of Critical Care, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States.
authors.forename: Deborah
authors.initials: D
authors.lastname: Donohoe
authors.affiliation: Division of Pediatric Surgery, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States.
authors.forename: Katherine
authors.initials: K
authors.lastname: Fredrich
authors.affiliation: Division of Pediatric Surgery, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States.
authors.forename: David M
authors.initials: DM
authors.lastname: Gourlay
authors.affiliation: Division of Critical Care, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee, Wisconsin, United States.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Liedel
mesh_terms: D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects*; D003911:Dextrans / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D053759:Interleukin-23 / Q000032:analysis / Q000494:pharmacology*; D007421:Intestine, Small / Q000166:cytology / Q000502:physiology; D008895:Milk, Human / Q000737:chemistry*; D062793:Occludin / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
chemical_list: D003911:Dextrans; D053759:Interleukin-23; D062793:Occludin; D012333:RNA, Messenger; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate