Department of Reproductive Medicine, Meizhou People's Hospital (Huangtang Hospital), Meizhou514000, Guangdong Province, China.
Zygote. 2023 Oct;31(5):498-506. doi: 10.1017/S0967199423000369. Epub 2023 Jul 24.
Placental trophoblastic cells play important roles in placental development and fetal health. However, the mechanism of trophoblastic cell fusion is still not entirely clear. The level of Tspan5 in the embryo culture medium was detected using enzyme-linked immunosorbent assay (ELISA). Fusion of BeWo cells was observed by immunofluorescence. Cell fusion-related factors and EMT-related factors were identified by qRT-PCR and western blotting. Notch protein repressor DAPT was used to verify the role of Tspan5 in BeWo cells. The expression of Tspan5 was significantly increased in embryo culture medium. The fusion of BeWo cells was observed after treatment with forskolin (FSK). Cell fusion-related factors (i.e. β-hCG and syncytin 1/2) and Tspan5 were significantly increased after FSK treatment. In addition, FSK treatment promoted EMT-related protein expression in BeWo cells. Knockdown of Tspan5 inhibited cell fusion and EMT-related protein levels. Notch-1 and Jagged-1 protein levels were significantly upregulated, and the EMT process was activated by overexpression of Tspan5 in FSK-treated BeWo cells. Interestingly, blocking the Notch pathway by the repressor DAPT had the opposite results. These results indicated that Tspan5 could promote the EMT process by activating the Notch pathway, thereby causing cell fusion. These findings contribute to a better understanding of trophoblast cell syncytialization and embryonic development. Tspan5 may be used as a therapeutic target for normal placental development.
胎盘滋养层细胞在胎盘发育和胎儿健康中发挥着重要作用。然而，滋养层细胞融合的机制尚不完全清楚。采用酶联免疫吸附试验（ELISA）检测胚胎培养液中 Tspan5 的水平。通过免疫荧光观察 BeWo 细胞的融合。通过 qRT-PCR 和 Western blot 鉴定细胞融合相关因子和 EMT 相关因子。使用 Notch 蛋白抑制剂 DAPT 验证 Tspan5 在 BeWo 细胞中的作用。胚胎培养液中 Tspan5 的表达明显增加。用forskolin (FSK)处理后观察到 BeWo 细胞的融合。FSK 处理后，细胞融合相关因子（即β-hCG 和 syncytin 1/2）和 Tspan5 的表达明显增加。此外，FSK 处理促进了 BeWo 细胞中 EMT 相关蛋白的表达。Tspan5 的敲低抑制了细胞融合和 EMT 相关蛋白的水平。Notch-1 和 Jagged-1 蛋白水平明显上调，在 FSK 处理的 BeWo 细胞中转染 Tspan5 可激活 EMT 过程。有趣的是，Notch 通路的抑制剂 DAPT 具有相反的结果。这些结果表明，Tspan5 可以通过激活 Notch 通路促进 EMT 过程，从而导致细胞融合。这些发现有助于更好地理解滋养层细胞的融合和胚胎发育。Tspan5 可能成为正常胎盘发育的治疗靶点。
