Phosphodiesterase inhibition attenuates alterations to the tight junction proteins occludin and ZO-1 in immunostimulated Caco-2 intestinal monolayers

Todd W. Costantini, Jessica Deree, William Loomis, James G. Putnam, Sunghyuk Choi, Andrew Baird, Brian P. Eliceiri, Vishal Bansal, Raul Coimbra

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


Aims: Under normal conditions, the intestinal mucosa acts as a local barrier to prevent the influx of luminal contents. The intestinal epithelial tight junction is comprised of several membrane associated proteins, including zonula occludens-1 (ZO-1) and occludin. Disruption of this barrier can lead to the production of pro-inflammatory mediators and ultimately multiple organ failure. We have previously shown that Pentoxifylline (PTX) decreases histologic gut injury and pro-inflammatory mediator synthesis. We hypothesize that PTX prevents the breakdown of ZO-1 and occludin in an in vitro model of immunostimulated intestinal cell monolayers. Main methods: Caco-2 human enterocytes were grown as confluent monolayers and incubated under control conditions, or with PTX (2 mM), Cytomix (TNF-α, IFN-γ, IL-1), or Cytomix + PTX for 24 h. Occludin and ZO-1 protein levels were analyzed by Western blot. Confocal microscopy was used to assess the cytoplasmic localization of ZO-1 and occludin. Key findings: Cytomix stimulation of Caco-2 cells resulted in a 50% decrease in both occludin and ZO-1 protein. Treatment with Cytomix + PTX restored both occludin and ZO-1 protein to control levels. Confocal microscopy images show that Cytomix caused an irregular, undulating appearance of ZO-1 and occludin at the cell junctions. Treatment with PTX prevented the Cytomix-induced changes in ZO-1 and occludin localization. Significance: Treatment with PTX decreases the pro-inflammatory cytokine induced changes in the intestinal tight junction proteins occludin and ZO-1. Pentoxifylline may be a useful adjunct in the treatment of sepsis and shock by attenuating intestinal barrier breakdown.

Original languageEnglish
Pages (from-to)18-22
Number of pages5
JournalLife Sciences
Issue number1-2
Publication statusPublished - 2009 Jan 2
Externally publishedYes


  • Caco-2 cells
  • Cytokines
  • Inflammation
  • Intestinal permeability
  • Occludin
  • Pentoxifylline
  • Phosphodiesterase inhibition
  • Shock
  • Tight junction
  • ZO-1

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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