A model to study the phenotypic changes of interstitial cells of Cajal in gastrointestinal diseases.
OBJECTIVE
Interstitial cells of Cajal (ICC) express the receptor tyrosine kinase, KIT, the receptor for stem cell factor. In the gastrointestinal (GI) tract, ICC are pacemaker cells that generate spontaneous electrical slow waves, and mediate inputs from motor neurons. Absence or loss of ICC are associated with GI motility disorders, including those consequent of diabetes. Studies of ICC have been hampered by the low density of these cells and difficulties in recognizing these cells in cell dispersions.


METHODS
Kit(+/copGFP) mice harboring a copepod super green fluorescent protein (copGFP) complementary DNA, inserted at the Kit locus, were generated. copGFP(+) ICC from GI muscles were analyzed using confocal microscopy and flow cytometry. copGFP(+) ICC from the jejunum were purified by a fluorescence-activated cell sorter and validated by cell-specific markers. Kit(+/copGFP) mice were crossbred with diabetic Lep(+/ob) mice to generate compound Kit(+/copGFP);Lep(ob/ob) mutant mice. copGFP(+) ICC from compound transgenic mice were analyzed by confocal microscopy.


RESULTS
copGFP in Kit(+/copGFP) mice colocalized with KIT immunofluorescence and thus was predominantly found in ICC. In other smooth muscles, mast cells were also labeled, but these cells were relatively rare in the murine GI tract. copGFP(+) cells from jejunal muscles were Kit(+) and free of contaminating cell-specific markers. Kit(+/copGFP);Lep(ob/ob) mice displayed ICC networks that were dramatically disrupted during the development of diabetes.


CONCLUSIONS
Kit(+/copGFP) mice offer a powerful new model to study the function and genetic regulation of ICC phenotypes. Isolation of ICC from animal models will help determine the causes and responses of ICC to therapeutic agents.
Ro
Seungil
S
Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557, USA.
Park
Chanjae
C
Jin
Jingling
J
Zheng
Huili
H
Blair
Peter J
PJ
Redelman
Doug
D
Ward
Sean M
SM
Yan
Wei
W
Sanders
Kenton M
KM
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D003433:Crosses, Genetic; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005767:Gastrointestinal Diseases / Q000378:metabolism* / Q000473:pathology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D056885:Interstitial Cells of Cajal / Q000378:metabolism* / Q000473:pathology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D010641:Phenotype; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism*
D015415:Biomarkers; D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit