title: Dynamic changes in EPCAM expression during spermatogonial stem cell differentiation in the mouse testis.
abstract: BACKGROUND
  Spermatogonial stem cells (SSCs) have the unique ability to undergo self-renewal division. However, these cells are morphologically indistinguishable from committed spermatogonia, which have limited mitotic activity. To establish a system for SSC purification, we analyzed the expression of SSC markers CD9 and epithelial cell adhesion molecule (EPCAM), both of which are also expressed on embryonic stem (ES) cells. We examined the correlation between their expression patterns and SSC activities.
  
  
  RESULTS
  By magnetic cell sorting, we found that EPCAM-selected mouse germ cells have limited clonogenic potential in vitro. Moreover, these cells showed stronger expression of progenitor markers than CD9-selected cells, which are significantly more enriched in SSCs. Fluorescence-activated cell sorting of CD9-selected cells indicated a significantly higher frequency of SSCs among the CD9(+)EPCAM(low/-) population than among the CD9(+)EPCAM(+) population. Overexpression of the active form of EPCAM in germline stem (GS) cell cultures did not significantly influence SSC activity, whereas EPCAM suppression by short hairpin RNA compromised GS cell proliferation and increased the concentration of SSCs, as revealed by germ cell transplantation.
  
  
  CONCLUSIONS
  These results show that SSCs are the most concentrated in CD9(+)EPCAM(low/-) population and also suggest that EPCAM plays an important role in progenitor cell amplification in the mouse spermatogenic system. The establishment of a method to distinguish progenitor spermatogonia from SSCs will be useful for developing an improved purification strategy for SSCs from testis cells.
authors.affiliation: Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Mito
authors.initials: M
authors.lastname: Kanatsu-Shinohara
authors.forename: Seiji
authors.initials: S
authors.lastname: Takashima
authors.forename: Kei
authors.initials: K
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinohara
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics* / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D000071858:Epithelial Cell Adhesion Molecule; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013091:Spermatogenesis / Q000235:genetics; D013093:Spermatogonia / Q000166:cytology / Q000378:metabolism*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000378:metabolism*; D060245:Tetraspanin 29 / Q000235:genetics / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; C554870:Cd9 protein, mouse; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D060245:Tetraspanin 29