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Hum Reprod. 2011 Jun;26(6):1296-306. doi: 10.1093/humrep/der026. Epub 2011 Feb 23.

Identification and characterization of repopulating spermatogonial stem cells from the adult human testis.

Author information

1
PrimeGen Biotech LLC, 213 Technology Drive, Irvine, CA 92618, USA. fizadyar@primegenbiotech.com

Abstract

BACKGROUND:

This study was conducted to identify and characterize repopulating spermatogonial stem cells (SSCs) in the adult human testes.

METHODS:

Testes biopsies from obstructive azoospermic patients and normal segments of human testicular tissue were used. Flow cytometry, real-time PCR and immunohistochemical analysis were performed. Purified human spermatogonia were transplanted into busulfan-treated recipient mouse testes and integrated cells were detected by human nuclear protein antibody co-localized with stem cell and germ cell markers.

RESULTS:

Testicular biopsies collected from obstructive azoospermic men showed similar morphology and distribution of markers to the normal human testes. Flow cytometry showed distinct populations of stage-specific embryonic antigen-4 (SSEA-4), CD49f and CD90 positive cells in the adult human testes. SSEA-4 (+) cells showed high expression levels of SSC-specific genes and high levels of telomerase activity. Extensive colonization of human cells in the mouse testes indicates the presence of highly enriched populations of SSCs in the SSEA-4 (+) sorted cells. All the HNP (+) cells in the mouse testes were positive for germ cell marker dead box mRNA helicase and only half of them were dimly positive for c-kit. In addition, subpopulations of human spermatogonia that colonized mouse testes were positively stained for CD49f, GPR-125, Nanog and Oct-4 indicating the existence of population of cells among human spermatogonia with SSC and pluripotent characteristics.

CONCLUSIONS:

This study clearly demonstrates that repopulating human SSCs have phenotypic characteristics of SSEA-4(+), CD49f(+), GPR-125(+)and c-Kit (neg/low). The results have direct implications for enrichment of human spermatogonia for further culture and germ cell differentiation studies.

PMID:
21349855
DOI:
10.1093/humrep/der026
[Indexed for MEDLINE]

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