Mus musculus Raw sequence reads
PTEN, a crucial tumor suppressor, exhibits high expression in testicular spermatogonia, suggesting its fundamental role in male germline maintenance. However, despite its clinical significance in tumorigenesis, the molecular mechanisms through which PTEN governs male fertility remain poorly understood. Here, we generated germline-specific PTEN conditional knockout mice to elucidate its function in spermatogenesis. PTEN deletion resulted in catastrophic disruption of testicular development characterized by premature and excessive differentiation of spermatogonial stem cells (SSCs), culminating in complete germ cell depletion in seminiferous tubules by postnatal day 20 and irreversible sterility. Transcriptomic profiling of purified spermatogonial populations from 5-day-old mice revealed accelerated entry into meiosis and aberrant activation of the PI3K-AKT-mTOR signaling cascade. Notably, pharmacological inhibition of this pathway using rapamycin or LY294002 failed to rescue the SSC differentiation phenotype either in vivo or in vitro, highlighting the irreversible nature of PTEN-mediated regulation. Successful restoration of spermatogenesis following wild-type SSC transplantation into PTEN-deficient testes confirmed that the testicular microenvironment remained functionally intact despite PTEN ablation. Importantly, PTEN knockdown in human spermatogonia similarly compromised proliferation capacity and downregulated genes essential for SSC identity maintenance, demonstrating evolutionary conservation of PTEN function across mammalian species. Our findings establish PTEN as an indispensable guardian of SSC self-renewal potential through precise regulation of differentiation timing, providing critical insights into the molecular basis of male fertility and potential therapeutic targets for male reproductive disorders.