Pharmaceutical Activation or Genetic Absence of ClC-2 Alters Tight Junctions During Experimental Colitis.
BACKGROUND
We have previously reported that the ClC-2 chloride channel has an important role in regulation of tight junction barrier function during experimental colitis, and the pharmaceutical ClC-2 activator lubiprostone initiates intestinal barrier repair in ischemic-injured intestine. Thus, we hypothesized that pharmaceutical ClC-2 activation would have a protective and therapeutic effect in murine models of colitis, which would be absent in ClC-2 mice.


METHODS
We administered lubiprostone to wild-type or ClC-2 mice with dextran sulfate sodium (DSS) or 2, 4, 5-trinitrobenzene sulfonic acid-induced colitis. We determined the severity of colitis and assessed intestinal permeability. Selected tight junction proteins were analyzed by Western blotting and immunofluorescence/confocal microscopy, whereas proliferative and differentiated cells were examined with special staining and immunohistochemistry.


RESULTS
Oral preventive or therapeutic administration of lubiprostone significantly reduced the severity of colitis and reduced intestinal permeability in both DSS and trinitrobenzene sulfonic acid-induced colitis. Preventive treatment with lubiprostone induced significant recovery of the expression and distribution of selected sealing tight junction proteins in mice with DSS-induced colitis. In addition, lubiprostone reduced crypt proliferation and increased the number of differentiated epithelial cells. Alternatively, when lubiprostone was administered to ClC-2 mice, the protective effect against DSS colitis was limited.


CONCLUSIONS
This study suggests a central role for ClC-2 in restoration of barrier function and tight junction architecture in experimental murine colitis, which can be therapeutically targeted with lubiprostone.
Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.
Younggeon
Y
Jin
Tiffany A
TA
Pridgen
Anthony T
AT
Blikslager
D000818:Animals; D015153:Blotting, Western; D000090007:CLC-2 Chloride Channels; D065101:Chloride Channel Agonists / Q000494:pharmacology*; D018118:Chloride Channels / Q000172:deficiency / Q000187:drug effects*; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy* / Q000235:genetics; D016264:Dextran Sulfate; D005455:Fluorescent Antibody Technique; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D000068238:Lubiprostone / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D010539:Permeability / Q000187:drug effects; D062725:Tight Junction Proteins / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D014301:Trinitrobenzenes
D000090007:CLC-2 Chloride Channels; D065101:Chloride Channel Agonists; D018118:Chloride Channels; D062725:Tight Junction Proteins; D014301:Trinitrobenzenes; D000068238:Lubiprostone; D016264:Dextran Sulfate