Determination of Feeder Cell‐Based Cellular Niches Supporting the Colonization and Maintenance of Spermatogonial Stem Cells from Prepubertal Domestic Cat Testes

Contents Recently, isolation and in vitro culture of putative spermatogonial stem cells ( SSC s) in the domestic cat have been conducted. However, the cellular niche conditions that facilitate the establishment and long‐term maintenance of feline SSC s ( FSSC s) have not been described. Therefore, we investigated the type of feeder cells used to stimulate colony formation and growth of FSSC s among the various factors in the FSSC niche. Spermatogonial stem cells isolated from feline testes were cultured on mitotically inactivated testicular stromal cells ( TSC s) derived from cats, dogs and mice, and mouse embryonic fibroblasts ( MEF s). The formation and growth of colonies derived from SSC s cultured on each type of feeder cell were identified at passage 0, and the morphology, alkaline phosphatase ( AP ) activity and expression of SSC ‐specific genes in surviving colonies were investigated at passage 4. Among these diverse feeder cells, TSC s from cat showed the greatest colony formation, growth and maintenance of FSSC s, and SSC colonies cultured by passage 4 showed a typical dome‐shaped morphology, AP activity and expression of SSC ‐specific genes ( NANOG , OCT 4 , SOX 2 and CD 9 ). Accordingly, these results demonstrate that feline TSC s could be used as feeder cells to support the establishment and maintenance of SSC s from domestic cats.