The Journal of Membrane Biology

, Volume 161, Issue 3, pp 263–274 | Cite as

Tumor Necrosis Factor-α Increases Sodium and Chloride Conductance Across the Tight Junction of CACO-2 BBE, a Human Intestinal Epithelial Cell Line

  • C.W.  Marano
  • S.A.  Lewis
  • L.A.  Garulacan
  • A.  Peralta Soler
  • J.M.  Mullin

Abstract.

CACO-2 BBE was used to determine the response of a gastrointestinal epithelium to tumor necrosis factor-α (TNF). Incubation of CACO-2 BBE with TNF did not produce any effect on transepithelial resistance (TER) within the first 6 hr but resulted in a 40–50% reduction in TER and a 30% decrease in Isc (short circuit current) relative to time-matched control at 24 hr. The decrease in TER was sustained up to 1 week following treatment with TNF and was not associated with a significant increase in the transepithelial flux of [14C]-d-mannitol or the penetration of ruthenium red into the lateral intercellular space. Dilution potential and transepithelial 22Na+ flux studies demonstrated that TNF-treatment of CACO-2 BBE cell sheets increased the paracellular permeability of the epithelium to Na+ and Cl. The increased transepithelial permeability did not associate with an increase in the incidence of apoptosis. However, there was a TNF-dependent increase in [3H]-thymidine labeling that was not accompanied by a change in DNA content of the cell sheet. The increase in transepithelial permeability was concluded to be across the tight junction because: (i) 1 mm apical amiloride reduced the basolateral to apical flux of 22Na+, and (ii) dilution potential studies revealed a bidirectionally increased permeability to both Na+ and Cl. These data suggest that the increase in transepithelial permeability across TNF-treated CACO-2 BBE cell sheets arises from an alteration in the charge selectivity of the paracellular conductive pathway that is not accompanied by a change in its size selectivity.

Key words: Tumor necrosis factor — Cytokine — Intestine — Epithelia — Tight junction — Paracellular 

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Copyright information

© 1998 Springer-Verlag New York Inc.

Authors and Affiliations

  • C.W.  Marano
    • 1
  • S.A.  Lewis
    • 2
  • L.A.  Garulacan
    • 1
  • A.  Peralta Soler
    • 1
  • J.M.  Mullin
    • 1
  1. 1.Lankenau Medical Research Center, 100 Lancaster Ave., Wynnewood, PA 19096, USAUS
  2. 2.University of Texas Medical Branch, Galveston, TX, USAUS

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