Generation of functionally competent testicular somatic cells from pluripotent stem cells

Cellular interactions between germ cells and gonadal somatic cells are essential for the progression of gametogenesis. Here, we report a culture method for generating fetal testicular somatic cell–like cells (fTeSLCs) from embryonic stem cells. These fTeSLCs exhibit a transcriptomic profile closely resembling that of their in vivo counterparts, including distinct cell populations corresponding to Sertoli cells and interstitial cells. For functional assessment, interstitial cell–like cells (ICLCs) and Sertoli-like cells (SerLCs) were isolated from fTeSLCs. ICLCs differentiated into Leydig cells when cocultured with testes lacking endogenous Leydig cells, thereby restoring androgenic support. SerLCs reconstituted the seminiferous epithelium following selective ablation of endogenous Sertoli cells. Both cell types supported spermatogenesis and generated spermatids reaching the elongating stage. Notably, round spermatids derived from these reconstructed systems produced viable offspring by round spermatid injection. These findings demonstrate that fTeSLCs can generate functional testicular somatic cells, providing a valuable platform for studying testis development and spermatogenesis.