Opposing regulation of the tight junction protein claudin-2 by interferon-gamma and interleukin-4.
BACKGROUND
The claudins are tight junction (TJ) proteins. Claudin-2 has been found to negatively affect the TJ, causing a decrease in transepithelial resistance. Patients with inflammatory bowel disease have altered intestinal permeability, suggesting a TJ disruption. Interferon-gamma (IFNgamma) and interleukin-4 (IL-4) negatively regulate each other and may have opposing roles in inflammatory bowel disease.


OBJECTIVE
IFNgamma and IL-4 will have opposing effects on the expression of claudin-2.


METHODS
Confluent T84 monolayers were apically incubated with IFNgamma or IL-4. The monolayers were immunofluorescently stained or lysed for Western blot with anti-claudin-2 or -4. Additional monolayers were grown on transwell plates, treated with IFNgamma or IL-4, measured for changes in transepithelial resistance, and assayed for changes in permeability using FITC-dextran-4000. Statistics were calculated by analysis of variance.


RESULTS
Addition of IFNgamma to T84 monolayers resulted in decreased claudin-2 and addition of IL-4 resulted in increased claudin-2 by Western blot. By immunofluorescence, there was a loss of claudin-2 from the membrane in cells treated with IFNgamma. Transepithelial resistance across T84 monolayers increased with IFNgamma and decreased with IL-4. T84 monolayer permeability increased with IL-4 but not with IFNgamma.


CONCLUSIONS
Incubation of T84 cells with IL-4 leads to increased claudin-2 with a corresponding decrease in transepithelial resistance and increase in permeability. Incubation of T84 cells with IFNgamma leads to decreased claudin-2 and increased transepithelial resistance. These cytokines have opposite effects on the expression of claudin-2 and the physiology of the TJ.
Wisner
Douglas M
DM
Department of Surgery, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
Harris
Leonard R
LR
Green
Cecelia L
CL
Poritz
Lisa S
LS
D015153:Blotting, Western; D002460:Cell Line; D057167:Claudins; D017097:Electric Impedance; D005455:Fluorescent Antibody Technique; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism* / Q000494:pharmacology; D015847:Interleukin-4 / Q000378:metabolism* / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D010539:Permeability / Q000187:drug effects; D019108:Tight Junctions / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*
C491875:CLDN2 protein, human; D057167:Claudins; C508598:IL4 protein, human; D008565:Membrane Proteins; D015847:Interleukin-4; D007371:Interferon-gamma