PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.


Journal Article

We have previously shown that PGE(2) and PGI(2) induce recovery of transepithelial resistance (TER) in ischemia-injured porcine ileal mucosa, associated with initial increases in Cl(-) secretion. We believe that the latter generates an osmotic gradient that stimulates resealing of tight junctions. Because of evidence implicating phosphatidylinositol 3-kinase (PI3K) in regulating tight junction assembly, we postulated that this signaling pathway is involved in PG-induced mucosal recovery. Porcine ileum was subjected to 45 min of ischemia, after which TER was monitored for a 180-min recovery period. Endogenous PG production was inhibited with indomethacin (5 microM). PGE(2) (1 microM) and PGI(2) (1 microM) stimulated recovery of TER, which was inhibited by serosal application of the osmotic agent urea (300 mosmol/kgH(2)O). The PI3K inhibitor wortmannin (10 nM) blocked recovery of TER in response to PGs or mucosal urea. Immunofluorescence imaging of recovering epithelium revealed that PGs restored occludin and zonula occludens-1 distribution to interepithelial junctions, and this pattern was disrupted by pretreatment with wortmannin. These experiments suggest that PGs stimulate recovery of paracellular resistance via a mechanism involving transepithelial osmotic gradients and PI3K-dependent restoration of tight junction protein distribution.

Full Text

Cited Authors

  • Little, D; Dean, RA; Young, KM; McKane, SA; Martin, LD; Jones, SL; Blikslager, AT

Published Date

  • January 2003

Published In

Volume / Issue

  • 284 / 1

Start / End Page

  • G46 - G56

PubMed ID

  • 12388204

Pubmed Central ID

  • 12388204

Electronic International Standard Serial Number (EISSN)

  • 1522-1547

International Standard Serial Number (ISSN)

  • 0193-1857

Digital Object Identifier (DOI)

  • 10.1152/ajpgi.00121.2002


  • eng