Visual selection of human potential spermatogonial stem cells by bead-tagging

Background: Isolation of human spermatogonial stem cells (hSSCs) could provide a clinical application for fertility preservation and additionally form the basis for in vitro-spermatogenesis. Human FGFR3-positive spermatogonia (SPG) are hSSC candidates since Fibroblast Growth Factor Receptor 3 is expressed exclusively in small non-proliferating subgroups of human A type SPG together with the pluripotency marker Undifferentiated embryonic cell Transcription Factor 1 (UTF1) [1-3]. Material & Methods: A pure FGFR3-positive potential human spermatogonial stem cell population from patients with full spermatogenesis was isolated by combining Dynabead® magnetic cell isolation and micromanipulative separation of bead-labeled cells during light microscopic visualisation (Fig. 1). Analysis of the isolated cells was conducted via immunocytochemistry and Live/Dead® staining (Invitrogen). Results: The isolated cells showed a similar cellular and nuclear morphology, a strong nuclear immunocytochemical UTF1-staining (Fig. 2A, B) and are vital (Fig. 2D, E, F). Conclusion: Our new single cell isolation protocol based on bead-tagging of the FGFR3-positive potential hSSCs enables down-stream applications and cell culture experiments without the inherent problem of somatic cell contaminations. Hence, it may finally build a fundament for the medical application of this very well-defined, homogeneous cell type. References: [1] von Kopylow et al., 2010. Hum Reprod 25: 1104–12. [2] von Kopylow et al., 2012. Histochem Cell Biol 138 (5): 759-72. [3] von Kopylow et al., 2012. Reprod 143(1): 45-57.