Comparing the adult and prepubertal testis: metabolic transitions and the change in the spermatogonial stem cell metabolic microenvironment.

Fetal human SSC precursors, or gonocytes, migrate into the seminiferous cords and supposedly mature to adult stem cells within the first year of human development. However, the SSC niche doesn't fully differentiate until puberty, when Sertoli cells dramatically rearrange the architecture and microenvironment within the seminiferous epithelium. Consequently, prepubertal and adult SSCs experience two distinct niche environments potentially affecting SSC metabolism and maturation. Indeed, the metabolic requirements of mouse PGCs and pig gonocytes are distinct from their adult counterparts and novel single cell RNA sequencing analysis of human and porcine SSCs during development confirms this metabolic transition. Knowledge of the metabolic requirements and their changes and regulation during SSC maturation is necessary to implement laboratory-based techniques and enable clinical use of SSCs. Based on the advancement in our understanding of germline metabolism circuits and maturation events of niche cells within the testis we propose a new definition of spermatogonial stem cell maturation and its amendment in the light of metabolic change. This article is protected by copyright. All rights reserved.