Dramatic Expansion of Germinal Stem Cells by Ectopically Expressed Human Glial Cell Line-Derived Neurotrophic Factor in Mouse Sertoli Cells

Although the mammalian germinal stem cell (GSC) provides a good model to investigate the regulation of stem cells, the small number of these cells currently available hampers elucidation of the regulatory mechanism. Here, we show the dramatic amplification of GSCs in mouse testis following transfection of human glial cell linederived neurotrophic factor cDNA into Sertoli cells using an efficient, in vivo electroporation technique. Transplantation analysis demonstrated not only GSC enrichment but also differentiation from stem cells into sperm. The GSC population, as estimated using a colony-formation assay, was approximately 20-fold greater than in cryptorchid testis, or approximately 500- to 1000-fold greater than in normal adult testis. This system should provide sufficient quantities of GSCs to accelerate our understanding of GSC properties, regulation mechanisms, and behavior control.