Increased expression and function of integrins in enterocytes by endotoxin impairs epithelial restitution

Faisal G. Qureshi, Cynthia Leaphart, Selma Cetin, Jun Li, Anatoly Grishin, Simon Watkins, Henri R. Ford, David J. Hackam

Research output: Contribution to journalArticle

Abstract

Background & Aims: Experimental necrotizing enterocolitis (NEC) is characterized by circulating endotoxin (lipopolysaccharide [LPS]) and impaired enterocyte migration. We hypothesized that LPS increases integrin function and cell-matrix adhesion, leading to impaired enterocyte migration in the pathogenesis of NEC. Methods: NEC-like intestinal injury was induced in newborn rats by hypoxia/gavage feedings, and restitution was determined by assessing bromodeoxyuridine-labeled enterocytes along the crypt-villus axis. Newborn mice were injected with 5 mg/kg LPS. IEC-6 cells were treated with LPS ± LY294002 or wortmannin, and β1- and α3-integrins were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunofluorescence. β1-integrin function was determined by adherence of fibronectin beads to IEC-6 monolayers. Migration of IEC-6 cells into a scraped wound was measured by time-lapse microscopy. Results: Newborn intestinal injury was associated with decreased intestinal restitution and increased α3- and β1-integrin expression in the ileal mucosa, which also was observed after LPS injection. In IEC-6 cells, LPS caused an increase in the expression of α3- and β1-integrins, a shift of β1-integrins from the cytoplasm to the plasma membrane and an increase in fibronectin bead adhesion during which β1-integrins accumulated underneath attached beads. These effects could be reversed with LY294002 or wortmannin, suggesting phosphatidylinositol- 3-phosphate kinase (PI3K) dependence. The increased integrin-matrix adhesion by LPS led to an inhibition of enterocyte migration, which could be reversed by anti-β1-antibodies. Conclusions: Enterocyte migration is inhibited by LPS through increased expression and function of α3- and β1-integrins. Modulation of enterocyte migration via integrins may provide novel insights into the pathogenesis of NEC, in which intestinal restitution is impaired.

Original languageEnglish (US)
Pages (from-to)1012-1022
Number of pages11
JournalGastroenterology
Volume128
Issue number4
DOIs
StatePublished - Apr 2005
Externally publishedYes

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

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