Signaling Molecules and Pathways Regulating the Fate of Spermatogonial Stem Cells

摘要

Spermatogenesis is the process that involves the division and differentiation ofspermatogonial stem cells (SSCs) into mature spermatozoa. SSCs are a subpopulation of type Aspermatogonia resting on the basement membrane in the mammalian testis. Self-renewal and dif-ferentiation of SSCs are the foundation of normal spermatogenesis, and thus a better understand-ing of molecular mechanisms and signaling pathways in the SSCs is of paramount importance forthe regulation of spermatogenesis and may eventually lead to novel targets for male contraceptionas well as for gene therapy of male infertility and testicular cancer. Uncovering the molecularmechanisms is also of great interest to a better understanding of SSC aging and for developingnovel therapeutic strategies for degenerative diseases in view of the recent work demonstratingthe pluripotent potential of the SSC. Progress has recently been made in elucidating the signalingmolecules and pathways that determine cell fate decisions of SSCs. In this review, we first addressthe morphological features, phenotypic characteristics, and the potential of SSCs, and then wefocus on the recent advances in defining the key signaling molecules and crucial signaling path-ways regulating self-renewal and differentiation of SSCs. The association of aberrant expression ofsignaling molecules and cascades with abnormal spermatogenesis and testicular cancer are alsodiscussed. Finally, we point out potential future directions to pursue in research on signaling path-ways of SSCs. Microsc. Res. Tech. 72:586-595, 2009.