Characterization of human spermatogonial stem cell markers in fetal, pediatric, and adult testicular tissues

Abstract

Autologous spermatogonial stem cell (SSC) transplantation is a potential therapeutic modality for patients with azoospermia following cancer treatment. For this promise to be realized, definitive membrane markers of prepubertal and adult human SSCs must be characterized in order to permit SSC isolation and subsequent expansion. This study further characterizes the markers of male gonocytes, prespermatogonia, and SSCs in humans. Human fetal, prepubertal, and adult testicular tissues were analyzed by confocal microscopy, fluorescence activated cell sorting (FACS), and qRT-PCR for expression of unique germ cell membrane markers. During male fetal development, THY1 and C-Kit are transient markers of gonocytes but not in prespermatogonia and post-natal SSCs. Although C-Kit expression is detected in gonocytes, THY1 expression is also detected in the somatic component of the fetal testes in addition to gonocytes. In the third trimester of gestation, THY1 expression shifts exclusively to the somatic cells of the testes where it continues to be detected only in the somatic cells postnatally. In contrast, SSEA-4 expression was only detected in the gonocytes, prespermatogonia, SSCs, and Sertoli cells of the fetal and prepubertal testes. After puberty, SSEA-4 expression can only be detected in primitive spermatogonia. Thus, although THY1 and C-Kit are transient markers of gonocytes, SSEA-4 is the only common membrane marker of gonocytes, prespermatogonia, and SSCs from fetal through adult human development. This finding is essential for the isolation of prepubertal and adult SSCs, which may someday permit fertility preservation and reversal of azoospermia following cancer treatment.

Spermatogonial stem cells: Current biotechnological advances in reproduction and regenerative medicine

“…Apparently, SSEA-4 seems to be conserved in humans [48] . SSCs from humans also express GPR125 [49] , besides GFRα1 [50] .…”

Optimal culture conditions are critical for efficient expansion of human testicular somatic and germ cells in vitro

“…Previous studies tried to characterize the different testicular cell subpopulations according to specific markers (14,15). CD90 has been suggested to be exclusively expressed in human somatic cells compared with germ cells, especially in the postnatal period (16).…”

Ethical, moral, and theological insights into advances in male pediatric and adolescent fertility preservation

“…The tissue is cryopreserved for long‐term storage and possible use. Testicular tissue from boys of all ages contains sperm stem cells (SSC) but may not yet contain mature spermatozoa (Altman et al ., ). Only spermatozoa can be used for contemporary fertility techniques.…”