Enteropathogenic Escherichia coli-induced myosin light chain phosphorylation alters intestinal epithelial permeability.
OBJECTIVE
Infection of epithelial cells with enteropathogenic Escherichia coli (EPEC) induces phosphorylation of the 20-kilodalton myosin light chain (MLC20). The physiological consequence of this biochemical observation, however, has not been discerned. The aim of this study was to determine if EPEC-induced phosphorylation of MLC20 was involved in the associated perturbation of intestinal epithelial barrier function.


METHODS
Cultured intestinal epithelial cells, T84, were infected with EPEC. The effects of protein kinase inhibitors on EPEC-induced perturbation of barrier function were assessed using electrophysiological techniques. Alterations in MLC20 phosphorylation were correlated with functional responses.


RESULTS
Inhibition of myosin light chain kinase, but not protein kinase C or tyrosine kinase, prevented the decrease in resistance caused by EPEC infection and significantly diminished EPEC-induced MLC20 phosphorylation. Epithelial cell monolayers genetically manipulated to constitutively increase MLC20 phosphorylation were relatively resistant to the effects of EPEC on barrier function.


CONCLUSIONS
For the first time, these data show that a physiological consequence of the long-recognized increase in MLC20 phosphorylation by EPEC is perturbation of intestinal epithelial barrier function, which probably contributes to the diarrhea associated with this infection.
Yuhan
R
R
Department of Medicine, University of Illinois, Chicago, USA.
Koutsouris
A
A
Savkovic
S D
SD
Hecht
G
G
D001422:Bacterial Adhesion / Q000502:physiology; D002460:Cell Line; D017097:Electric Impedance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000502:physiology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D007422:Intestines / Q000382:microbiology*; D018994:Myosin Light Chains / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D010539:Permeability; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D018994:Myosin Light Chains; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D009219:Myosin-Light-Chain Kinase