Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics, Institute of Urology, Peking University Shenzhen Hospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, 518036, China.
Department of Obstetrics, the People's Hospital of Longhua, Shenzhen, 518109, China.
Reprod Sci. 2020 Jul;27(7):1443-1454. doi: 10.1007/s43032-020-00156-z. Epub 2020 Jan 28.
Sertoli cells are important for spermatogenesis not only by directly interacting with germ line cells in the seminiferous epithelium but also by constituting the blood-testis barrier (BTB) structure to create a favorable environment for spermatogenesis. Blind sterile (bs) male mice are infertile, with excessive germ cell apoptosis and spermatogenesis arrest. TBC1D20 (TBC1 domain family member 20) deficiency has been identified as the causative mutation in bs mice. However, whether TBC1D20 loss of function also impairs BTB integrity, which further contributes to the failed spermatogenesis of bs male mice, remains unclear. In the present study, biotin tracer assay and transmission electron microscopy showed severely disrupted BTB integrity in bs testes. Compared to the wild-type Sertoli cells, BTB components of cultured bs Sertoli cells in vitro was perturbed with downregulation of E-cadherin, ZO-1, β-catenin, and Claudin 11. The obvious rearrangement of F-actin indicated disrupted epithelial-mesenchymal balance in TBC1D20-deficient Sertoli cells. The ability of bs Sertoli cells to maintain the clone formation of spermatogonia stem cells was also obviously limited. Furthermore, the decreasing of SOX9 (sex-determining region Y box 9) and WT1 (Wilms' tumor 1) and increasing of vimentin in bs Sertoli cells indicated that TBC1D20 loss of function attenuated the differentiation progression of bs Sertoli cells. In summary, TBC1D20 loss of function impedes the maturation of adult Sertoli cells and resulted in impaired BTB integrity, which is further implicated in the infertile phenotype of bs male mice.
支持细胞不仅通过与生精上皮中的生殖细胞直接相互作用,而且通过构成血睾屏障 (BTB) 结构为精子发生创造有利环境,对精子发生至关重要。盲不育 (bs) 雄性小鼠不育,具有过多的生殖细胞凋亡和精子发生停滞。已经确定 TBC1D20(TBC1 结构域家族成员 20)缺陷是 bs 小鼠的致病突变。然而,TBC1D20 功能丧失是否也会损害 BTB 完整性,从而进一步导致 bs 雄性小鼠的精子发生失败,尚不清楚。在本研究中,生物素示踪剂测定和透射电子显微镜显示 bs 睾丸中的 BTB 完整性严重受损。与野生型支持细胞相比,体外培养的 bs 支持细胞的 BTB 成分受到干扰,E-钙粘蛋白、ZO-1、β-连环蛋白和 Claudin 11 下调。F-肌动蛋白的明显重排表明 TBC1D20 缺陷的支持细胞中上皮-间充质平衡被破坏。bs 支持细胞维持精原干细胞克隆形成的能力也明显受到限制。此外,bs 支持细胞中 SOX9(性别决定区 Y 框 9)和 WT1(Wilms' 肿瘤 1)的减少和波形蛋白的增加表明 TBC1D20 功能丧失减弱了 bs 支持细胞的分化进展。总之,TBC1D20 功能丧失阻碍了成年支持细胞的成熟,并导致 BTB 完整性受损,这进一步表明 bs 雄性小鼠的不育表型。