Claudins regulate the intestinal barrier in response to immune mediators

T Kinugasa, T Sakaguchi, X Gu, HC Reinecker - Gastroenterology, 2000 - Elsevier
T Kinugasa, T Sakaguchi, X Gu, HC Reinecker
Gastroenterology, 2000Elsevier
Background & Aims: To determine the functional role of immune mediators in the formation
of the intestinal barrier, we have examined the regulation of claudin expression by
interleukin (IL)-17 in human intestinal epithelial cells. Methods: Expression of claudins,
extracellular signal-related (ERK) mitogen-activated protein kinases (MAPKs), and activated
ERK MAPKs was determined by immunoblotting. Claudin membrane association was
assessed by immunohistochemistry and claudin messenger RNA expression by Northern …
Background & Aims
To determine the functional role of immune mediators in the formation of the intestinal barrier, we have examined the regulation of claudin expression by interleukin (IL)-17 in human intestinal epithelial cells.
Methods
Expression of claudins, extracellular signal-related (ERK) mitogen-activated protein kinases (MAPKs), and activated ERK MAPKs was determined by immunoblotting. Claudin membrane association was assessed by immunohistochemistry and claudin messenger RNA expression by Northern blot analysis. Intestinal epithelial barrier function was characterized through transepithelial electrical resistance and mannitol tracer flux.
Results
IL-17 induced the development of a paracellular barrier of T84 cell monolayers. Inhibition of ERK activation with the MEK inhibitor PD98059 blocked IL-17 as well as basal development of tight junctions in T84 cells. IL-17 induced formation of tight junctions correlated with up-regulation of claudin-1 and claudin-2 gene transcription. Inhibition of MEK reduced the activated and basal expression of claudin-2 messenger RNA and protein expression. Functional MEK was required for the expression and membrane association of claudin-2 but not claudin-1 in T84 cells.
Conclusions
MEK activity is required for claudin-mediated formation of tight junctions. IL-17 is able to regulate the intestinal barrier through the ERK MAPK pathway. GASTROENTEROLOGY 2000;118:1001-1011
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