Tumour necrosis factor-α induces morphological and functional alterations of intestinal ht29 cl.19a cell monolayers

P. Rodriguez*, M. Heyman, C. Candalh, M. A. Blaton, C. Bouchaud

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

88 Scopus citations

Abstract

TNF-α is a widely distributed proinflammatory cytokine, involved in many disease states. Although it has widely distributed effects, a precise mechanism of action has never been described, in particular at the epithelial level. Morpho-functional changes of the intestinal epithelial monolayer HT29 cl.19A exposed to TNF-α were therefore assessed, using electron microscopy (including freeze-fracture replica analysis), as well as measurement of mannitol, Na+ and horseradish peroxidase fluxes across intestinal HT29 cl.19A cell monolayers using Ussing chambers. TNF-α receptors were induced on HT29 cl.19A cells by a small non-toxic dose of IFN-γ (5 U/ml). After 4 h of the combined presence of TNF-α (10 ng/ml) and IFN-γ (5 U/ml), the tight junction structure was altered as shown by a significant decrease in the average strand number measured in the apico-basal direction (5.50 ± 2.70 vs 3.73 ± 1.39 in control and treated cells respectively, P < 0.0001) and by a significant decrease in junctional depth (0.27 ± 0.14 and 0.17 ± 0.10 μm in control and treated cells respectively, P < 0.0001). These results are in agreement with a decrease in number of ‗kiss‘ sites between contiguous membranes of TNF-α treated cells observed in ultrathin sections. In parallel, the paracellular permeability of intestinal monolayers increased in the presence of TNF-α compared to controls as shown by the increase in mannitol (32.4 ± 4.7 vs 9.3 ± 0.7 μg/h.cm2, P < 0.0003), Na (216 ± 27 vs 83 ± 4 μg/h.cm2, P < 0.0003) and HRP (274 ± 67 vs 34 ± 12 ng/h.cm2, P < 0.004) fluxes and by the decrease in electrical resistance (43 ± 7 vs 112 ± 10 Ω.cm2, P < 0.0001). These results indicate that, providing receptors are present. TNF-α induces an alteration of epithelial tight junctions leading to a disruption of the epithelial barrier capacity.

Original languageEnglish
Pages (from-to)441-448
Number of pages8
JournalCytokine
Volume7
Issue number5
DOIs
StatePublished - 1 Jan 1995
Externally publishedYes

Keywords

  • Cytokine
  • Electron microscopy
  • Freeze-fracture
  • Intestinal barrier
  • Tight junction

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