title: Gene expression profiling of rat spermatogonia and Sertoli cells reveals signaling pathways from stem cells to niche and testicular cancer cells to surrounding stroma.
abstract: BACKGROUND
  Stem cells and their niches are studied in many systems, but mammalian germ stem cells (GSC) and their niches are still poorly understood. In rat testis, spermatogonia and undifferentiated Sertoli cells proliferate before puberty, but at puberty most spermatogonia enter spermatogenesis, and Sertoli cells differentiate to support this program. Thus, pre-pubertal spermatogonia might possess GSC potential and pre-pubertal Sertoli cells niche functions. We hypothesized that the different stem cell pools at pre-puberty and maturity provide a model for the identification of stem cell and niche-specific genes. We compared the transcript profiles of spermatogonia and Sertoli cells from pre-pubertal and pubertal rats and examined how these related to genes expressed in testicular cancers, which might originate from inappropriate communication between GSCs and Sertoli cells.
  
  
  RESULTS
  The pre-pubertal spermatogonia-specific gene set comprised known stem cell and spermatogonial stem cell (SSC) markers. Similarly, the pre-pubertal Sertoli cell-specific gene set comprised known niche gene transcripts. A large fraction of these specifically enriched transcripts encoded trans-membrane, extra-cellular, and secreted proteins highlighting stem cell to niche communication. Comparing selective gene sets established in this study with published gene expression data of testicular cancers and their stroma, we identified sets expressed genes shared between testicular tumors and pre-pubertal spermatogonia, and tumor stroma and pre-pubertal Sertoli cells with statistic significance.
  
  
  CONCLUSIONS
  Our data suggest that SSC and their niche specifically express complementary factors for cell communication and that the same factors might be implicated in the communication between tumor cells and their micro-environment in testicular cancer.
authors.affiliation: Molecular Gynecology and Obstetrics Laboratory, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Ryser
authors.forename: Dominique
authors.initials: D
authors.lastname: Glauser
authors.forename: Michelle
authors.initials: M
authors.lastname: Vigier
authors.forename: Yong Qiang
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Philippe
authors.initials: P
authors.lastname: Tachini
authors.forename: Werner
authors.initials: W
authors.lastname: Schlegel
authors.forename: Philippe
authors.initials: P
authors.lastname: Durand
authors.forename: Irmgard
authors.initials: I
authors.lastname: Irminger-Finger
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D020869:Gene Expression Profiling; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012708:Sertoli Cells / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D013093:Spermatogonia / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism*; D013736:Testicular Neoplasms / Q000378:metabolism*