Sun Tao, Xin Zhongcheng, Jin Zhe, Wu Yiguang, Gong Yanqing
Andrology Center, Peking University First Hospital, Peking University, Xicheng District, Beijing, People's Republic of China.
Mol Cell Biochem. 2008 Dec;319(1-2):1-7. doi: 10.1007/s11010-008-9869-3. Epub 2008 Jul 22.
The roles of TGF-beta and the interaction between TGF-beta and EGFR signaling are critical in Sertoli cell, though the knowledge about them is limited. RT-PCR was used to characterize the status of TGF-beta signaling in clinical testicular specimens with complete Sertoli cell-only syndrome (SCOS). The mouse Sertoli cell TM4 was used to investigate the interaction between TGF-beta and EGFR signaling by using mitogenic assay, luciferase assay, and western blot, while TM3 (mouse leydig cell), 3T3 (mouse embryo fibroblasts), and B82 (mouse lung fibroblasts) were selected as control. The RT-PCR assay indicated that the expression levels of TbetaRII and Smad2 in SCOS testes were upregulated compared to that in the normal controls. In the in vitro experiment, the TGF-beta1 downregulated cellular proliferation of TM3 and B82 cell (P < 0.05), but it did not changed the proliferation of TM4 and 3T3 cells (P > 0.05). On contrast, TGF-beta1 only increased the TGF response elements p3TP-lux activity significantly (P < 0.05) in Sertoli cell TM4. Also, the Western blot assay shows an obvious increase of Smad2 in TM4, 3T3, and TM3 cells after TGF-beta1 treatment while the EGFR expression level was significantly increased in TM4 cells only. In conclusion, the TGF-beta pathway and the cross-link between TGF-beta and EGFR signaling may play an important role on the dysfunction of Sertoli cells which induce germ stem cells' disappearance in SCOS.
转化生长因子β（TGF-β）的作用以及TGF-β与表皮生长因子受体（EGFR）信号之间的相互作用在支持细胞中至关重要，尽管对此的了解有限。采用逆转录聚合酶链反应（RT-PCR）来表征完全性唯支持细胞综合征（SCOS）临床睾丸标本中TGF-β信号的状态。利用促有丝分裂试验、荧光素酶试验和蛋白质免疫印迹法，选用小鼠支持细胞TM4来研究TGF-β与EGFR信号之间的相互作用，同时选用TM3（小鼠睾丸间质细胞）、3T3（小鼠胚胎成纤维细胞）和B82（小鼠肺成纤维细胞）作为对照。RT-PCR检测表明，与正常对照相比，SCOS睾丸中TβRII和Smad2的表达水平上调。在体外实验中，TGF-β1下调了TM3和B82细胞的细胞增殖（P<0.05），但未改变TM4和3T3细胞的增殖（P>0.05）。相反，TGF-β1仅显著增加了支持细胞TM4中TGF反应元件p3TP-lux的活性（P<0.05）。此外，蛋白质免疫印迹分析显示，TGF-β1处理后，TM4、3T3和TM3细胞中Smad2明显增加，而仅TM4细胞中EGFR表达水平显著增加。总之，TGF-β信号通路以及TGF-β与EGFR信号之间的交联可能在导致SCOS中生殖干细胞消失的支持细胞功能障碍中起重要作用。
