Concise Review: Defining Characteristics of Mammalian Spermatogenic Stem Cells§

Authors

  • Michael D. Griswold,

    Corresponding author
    1. School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
    • School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington 99164-7520, USA
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    • Telephone: 509 335 6281; Fax: 509 335 9688

  • Jon M. Oatley

    Corresponding author
    1. School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
    • School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
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    • Telephone: 509 335 0499; Fax: 509 335 9688


  • Author contributions: The authors contributed equally to all facets of this work including: Conception and design, assembly of data, data analysis and interpretation, manuscript writing, and final approval of manuscript.

  • Disclosure of potential conflicts of interest is found at the end of this article.

  • §

    First published online in STEM CELLSEXPRESS October 16, 2012.

Abstract

The enormous number of sperms produced daily and over the lifetime of mammals requires a stable source of stem cells that give rise to progenitor cells that proceed through spermatogenesis. Spermatogenic stem cells develop from primitive germ cells that occupy the developing gonad. A transplantation assay was developed for the spermatogenic stem cells, and it remains the only functional measure of authentic stem cells in the testis. Somatic cells comprise a “niche” environment that is essential for the maintenance of stem cell activity. Dividing progenitor cells have intercellular bridges and form syncytia with 2, 4, 8, or 16 cells. Fragmentation of these syncytia may allow some progenitor cells to occupy “niches” and function as stem cells, but this notion requires further investigation. Spermatogenic stem cells can be maintained in culture and are influenced by a number of growth factors. Thus far, the ultimate differentiation of cultured stem cells into functional gametes has not been demonstrated with any efficiency and reproducibility. The ability to maintain spermatogenic stem cells in culture and to induce differentiation into haploid cells and sperm could have many important implications for human medicine. STEM Cells2013;31:8–11

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