GDNF family receptor alpha1 phenotype of spermatogonial stem cells in immature mouse testes.
Spermatogonial stem cells (SSCs) are essential for spermatogenesis, and these adult tissue stem cells balance self-renewal and differentiation to meet the biological demand of the testis. The developmental dynamics of SSCs are controlled, in part, by factors in the stem cell niche, which is located on the basement membrane of seminiferous tubules situated among Sertoli cells. Sertoli cells produce glial cell line-derived neurotrophic factor (GDNF), and disruption of GDNF expression results in spermatogenic defects and infertility. The GDNF signals through a receptor complex that includes GDNF family receptor alpha1 (GFRA1), which is thought to be expressed by SSCs. However, expression of GFRA1 on SSCs has not been confirmed by in vivo functional assay, which is the only method that allows definitive identification of SSCs. Therefore, we fractionated mouse pup testis cells based on GFRA1 expression using magnetic activated cell sorting. The sorted and depleted fractions of GFRA1 were characterized for germ cell markers by immunocytochemistry and for stem cell activity by germ cell transplantation. The GFRA1-positive cell fraction coeluted with other markers of SSCs, including ITGA6 and CD9, and was significantly depleted of KIT-positive cells. The transplantation results confirmed that a subpopulation of SSCs expresses GFRA1, but also that the stem cell pool is heterogeneous with respect to the level of GFRA1 expression. Interestingly, POU5F1-positive cells were enriched nearly 15-fold in the GFRA1-selected fraction, possibly suggesting heterogeneity of developmental potential within the stem cell pool.
Buageaw
Anyanee
A
Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Sukhwani
Meena
M
Ben-Yehudah
Ahmi
A
Ehmcke
Jens
J
Rawe
Vanesa Y
VY
Pholpramool
Chumpol
C
Orwig
Kyle E
KE
Schlatt
Stefan
S
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002454:Cell Differentiation; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000378:metabolism*; D018189:Immunomagnetic Separation; D039503:Integrin alpha6 / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D015203:Reproducibility of Results; D013093:Spermatogonia / Q000378:metabolism* / Q000637:transplantation; D033581:Stem Cell Transplantation / Q000379:methods; D013234:Stem Cells / Q000378:metabolism*; D013737:Testis / Q000166:cytology* / Q000378:metabolism; D060245:Tetraspanin 29
D015703:Antigens, CD; C554870:Cd9 protein, mouse; C494988:Gfra1 protein, mouse; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D039503:Integrin alpha6; D008562:Membrane Glycoproteins; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D060245:Tetraspanin 29; D019009:Proto-Oncogene Proteins c-kit