Specification of germ cell-like cells from induced pluripotent stem cells has become a clinically relevant tool for research. Research on initial embryonic processes is often limited by the access to foetal tissue, and in humans, the molecular events resulting in primordial germ cell (PGC) specification and sex determination remain to be elucidated. A deeper understanding of the underlying processes is crucial to describe pathomechanisms leading to impaired reproductive function. Several protocols have been established for the specification of human pluripotent stem cell towards early PGC-like cells (PGCLC), currently representing the best model to mimic early human germline developmental processes in vitro. Further sex determination towards the male lineage depends on somatic gonadal cells providing the necessary molecular cues. By establishing a culture system characterized by the re-organization of somatic cells from postnatal rat testes into cord-like structures and optimizing efficient PGCLC specification protocols, we facilitated the co-culture of human germ cell-like cells within a surrogate testicular microenvironment. Specified conditions allowed the survival of rat somatic testicular and human PGCLCs for 14 days. Human cells maintained the characteristic expression of octamer-binding transcription factor 4, SRY-box transcription factor 17, and transcription factor AP-2 gamma and were recovered from the xeno-organoids by cell sorting. This novel xeno-organoid approach will allow the in vitro exploration of early sex determination of human PGCLCs.

中文翻译：

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一种新的异种类器官方法：探索人 iPSC 衍生的 PGC 样细胞和大鼠睾丸细胞之间的串扰

来自诱导多能干细胞的生殖细胞样细胞的规范已成为临床相关的研究工具。对初始胚胎过程的研究通常受到胎儿组织的限制，而在人类中，导致原始生殖细胞 (PGC) 特化和性别决定的分子事件仍有待阐明。深入了解潜在过程对于描述导致生殖功能受损的病理机制至关重要。已经建立了几种用于规范人类多能干细胞对早期 PGC 样细胞 (PGCLC) 的协议，目前代表了在体外模拟早期人类生殖系发育过程的最佳模型. 对男性谱系的进一步性别决定取决于提供必要分子线索的体细胞性腺细胞。通过建立以出生后大鼠睾丸的体细胞重组为索状结构为特征的培养系统，并优化有效的 PGCLC 规范方案，我们促进了人类生殖细胞样细胞在替代睾丸微环境中的共培养。特定条件允许大鼠体细胞睾丸和人 PGCLC 存活 14 天。人类细胞保持了八聚体结合转录因子 4、SRY-box 转录因子 17 和转录因子 AP-2 γ 的特征表达，并通过细胞分选从异种类器官中回收。这种新颖的异种类器官方法将允许在体外 探索人类 PGCLCs 的早期性别决定。