Liang Dongli, Sun Qi, Zhu Zijue, Wang Chuanyun, Ye Shicheng, Li Zheng, Wang Yuan
Laboratory Animal Center, Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai, China.
Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
Front Cell Dev Biol. 2022 May 23;10:883314. doi: 10.3389/fcell.2022.883314. eCollection 2022.
Spermatogonial stem cells are the foundation of continuous spermatogenesis in adult mammals. Xenograft models have been established to define human SSCs, mostly using infertile and immune-deficient mice as the recipients for human germ cell transplantation. However, it is time-consuming to prepare such recipients using irradiation or chemotherapeutic agents, and this approach may also introduce confounding factors when residual endogenous germ cells recover in transplanted recipients. It remains to be determined whether immune-competent genetically infertile mice can be suitable recipients for xenotransplantation. In this study, we observed similar engraftment efficiencies when using spermatogonia from human biopsied testes across immune-deficient nude mice, immune-competent ICR mice, and genetically infertile mice, suggesting minimal immunological rejection from immune-competent mouse recipients upon xenotransplantation of human germ cells. More importantly, we derived EpCAM negative and TNAP positive spermatogonia-like cells (SLCs) from human pluripotent stem cells (PSCs), which highly expressed spermatogonial markers including PLZF, INTERGRINα6, TKTL1, CD90, and DRMT3. We found that upon transplantation, these SLCs proliferated and colonized at the basal membrane of seminiferous tubules in testes of both immune-deficient nude mice and mice, though complete spermatogenesis would likely require supporting human signaling factors and microenvironment. Taken together, our study functionally defined the cell identity of PSC-derived SLCs, and supported xenotransplantation using genetically infertile recipients as a convenient model for functionally evaluating spermatogonia derived from different species.
精原干细胞是成年哺乳动物持续精子发生的基础。已建立异种移植模型来定义人类精原干细胞，大多使用不育和免疫缺陷小鼠作为人类生殖细胞移植的受体。然而，使用辐射或化疗药物制备此类受体耗时较长，而且当移植受体中残留的内源性生殖细胞恢复时，这种方法可能还会引入混杂因素。具有免疫能力的遗传性不育小鼠是否适合作为异种移植的受体仍有待确定。在本研究中，我们观察到，将人类活检睾丸中的精原细胞分别移植到免疫缺陷裸鼠、具有免疫能力的ICR小鼠和遗传性不育小鼠体内时，其植入效率相似，这表明人类生殖细胞异种移植后，具有免疫能力的小鼠受体产生的免疫排斥极小。更重要的是，我们从人类多能干细胞（PSC）中获得了EpCAM阴性和TNAP阳性的精原细胞样细胞（SLC），这些细胞高度表达包括PLZF、整合素α6、TKTL1、CD90和DRMT3在内的精原细胞标志物。我们发现，移植后，这些SLC在免疫缺陷裸鼠和[此处原文缺失小鼠品系信息]小鼠睾丸的生精小管基底膜处增殖并定植，不过完整的精子发生可能需要人类信号因子和微环境的支持。综上所述，我们的研究从功能上定义了PSC来源的SLC的细胞特性，并支持使用遗传性不育受体进行异种移植，作为从功能上评估不同物种来源的精原细胞的便捷模型。
