人精原干细胞表面标志物NGFR及配体NGF对其自我更新的作用与机制

Spermatogenesis is a process that spermatogonial stem cells (SSCs) self-renew and differentiate into the mature spermatozoa. Through comparing the mRNA profiles of germ cell of each stage in human spermatogenesis, we have predicted that NGFR was specifically expressed in human SSCs. In our previous study, cell-specific expression pattern of Ngfr and its ligand Ngf has been detected in mice seminiferous tubule. Moreover, we have verified that Ngf could promote the proliferation and self-renewal of mouse SSCs. Numerous studies have illustrated that NGF-NGFR is a key signal pathway involved in regulation of self-renewal and differentiation in stem cells, whereas its effect in human SSCs remains unknown. In this project, the following studies will be conducted: 1) Identification of NGFR and NGF localization in human testicular tissue; 2) The effect of NGFR and NGF in proliferation and self-renewal of human SSCs; 3) The mechanism of NGFR and NGF in proliferation and self-renewal of human SSCs. This study will demonstrate that NGFR is a surface marker of human SSCs. What’s more, it would be proved that NGF-NGFR is the key signal pathway in regulation of the self-renewal of human SSCs. In conclusion, this project will provide insightful information into the etiology of male infertility, the regulation of the human spermatogenesis and the future male fertility preservation.

精子发生是精原干细胞（SSCs）自我更新和分化为精子的过程。本团队通过人精子发生转录组学研究，预测并初步验证NGFR为SSCs特异表面标志物。前期研究证实Ngfr及其配体Ngf在小鼠精子发生过程中具有特异时空表达模式，并可以促进SSCs增殖和自我更新。相关研究表明，NGF-NGFR是调控干细胞命运的关键通路，但对人SSCs的作用及机制未见报道。本项目拟开展以下研究：1）明确NGFR及其配体NGF在人睾丸生精小管的时空表达特征；2）探讨NGFR及其配体NGF对人SSCs增殖和自我更新的调控作用；3）揭示NGFR及其配体NGF调控人SSCs增殖与自我更新的信号转导机制。本研究将证实NGFR为SSCs的特异表面标志物，NGF-NGFR是调控SSCs自我更新的关键通路，为阐明人SSCs自我更新机制提供理论基础，为治疗生精障碍及未成年男性肿瘤患者的生育力保存提供新靶标。

精子发生是一个极其重要和复杂的过程，本研究基于单细胞测序技术探讨NGFR在正常睾丸和非梗阻性无精子症患者睾丸中的表达特征，明确NGFR在人睾丸组织中的时空表达特征，提示神经生长因子通路在间质干细胞的自我更细与分化过程中起到非常重要的作用。NGFR在OA患者以及SCOS患者的睾丸组织中的间质干细胞的表达差异明显，OA患者中的NGFR的表达比SCOS患者睾丸组织中的表达含量高，提示间质干细胞的NGFR通路对于非梗阻性无精子症的发病起到一定影响。克氏综合征患者的Leydig细胞和管周细胞受额外X染色体的影响相对其他细胞较小；克氏综合征病人支持细胞发生较大的转录组特征改变与其XIST表达缺失相关，而Leydig细胞等睾丸体细胞高表达XIST，具有良好的X染色体沉默机制，能够减弱额外X染色体造成的影响。进一步证实NGFR为间质干细胞的特异表面标志物，为阐明不同类型生精障碍中睾丸间质细胞功能和作用，为治疗生精障碍和研究精子发生提供新靶标。