Spatial and temporal expression patterns of the epithelial cell adhesion molecule (EpCAM/EGP-2) in developing and adult kidneys.
BACKGROUND
The epithelial cell adhesion molecule (EpCAM) is expressed by most epithelia and is involved in processes fundamental for morphogenesis, including cell-cell adhesion, proliferation, differentiation, and migration. Previously, a role for EpCAM in pancreatic morphogenesis was confirmed in vitro. Furthermore, changes in the EpCAM expression pattern were found in developing lung and thymus and in the regenerating liver. Therefore, EpCAM was proposed to be a morphoregulatory molecule.


METHODS
Using immunohistochemistry, the expression pattern of human and murine homologues of EpCAM was characterized in adult and embryonic kidneys from humans and human-EpCAM (hEpCAM)-transgenic mice.


RESULTS
EpCAM expression was found in the ureteric bud throughout nephrogenesis. EpCAM was not expressed in the metanephric mesenchyme. In comma- and S-shaped bodies, both metanephric mesenchyme derived structures, EpCAM expression appeared by E13.5. In adult kidneys, most epithelia expressed varying levels of EpCAM, as confirmed by double staining for human EpCAM and segment-specific nephron markers. Podocytes were EpCAM negative. At the cellular level, the EpCAM expression shifted from apical in embryonic to basolateral in adult kidneys.


CONCLUSIONS
The spatiotemporal expression pattern of EpCAM changes during nephrogenesis. In the adult kidney, the expression varies markedly along the nephron. These data provide a basis for further studies on EpCAM in developing and adult kidneys.
Trzpis
Monika
M
Department of Pathology and Laboratory Medicine, University Medical Center Groningen (UMCG), Groningen, The Netherlands.
Popa
Eliane R
ER
McLaughlin
Pamela M J
PM
van Goor
Harry
H
Timmer
Albertus
A
Bosman
Gerrit W
GW
de Leij
Lou M F H
LM
Harmsen
Martin C
MC
D000328:Adult; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism*; D016466:CHO Cells; D015815:Cell Adhesion Molecules / Q000276:immunology / Q000378:metabolism*; D016764:Cell Polarity; D006224:Cricetinae; D003412:Cricetulus; D000071858:Epithelial Cell Adhesion Molecule; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000196:embryology / Q000254:growth & development / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013194:Staining and Labeling
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule