环磷酸腺苷（cAMP）直接激活交换蛋白（Epac）在人胎盘 BeWo 细胞中 cAMP 依赖性功能分化和融合中的可能作用。

Possible role of the exchange protein directly activated by cyclic AMP (Epac) in the cyclic AMP-dependent functional differentiation and syncytialization of human placental BeWo cells.

机构信息

Department of Endocrine Pharmacology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.

出版信息

Hum Reprod. 2010 Sep;25(9):2229-38. doi: 10.1093/humrep/deq190. Epub 2010 Jul 27.

DOI:10.1093/humrep/deq190

PMID:20663796

Abstract

BACKGROUND

The mononuclear villous cytotrophoblast (CTB) differentiates and fuses to the multinucleated syncytiotrophoblast (STB), which produces hCG and progesterone. cAMP-mediated intracellular pathways are involved in the process of endocrine differentiation and fusion (syncytialization). The exchange protein directly activated by cAMP (Epac) is a mediator of cAMP signaling. We examined the differential roles of Epac and protein kinase A (PKA) signaling in the cell fusion and differentiation of trophoblast-derived BeWo cells.

METHODS

Epac1 and Epac2 were localized in human placental tissue (n = 9) by immunohistochemistry. The PKA-selective cAMP analog (N(6)-phenyl-cAMP, Phe) or Epac-selective cAMP analog (CPT) was tested for effects on hCG and progesterone production, and syncytialization in BeWo cells. The effect of knockdown of Epac or its downstream target molecule (Rap1) on syncytialization was evaluated.

RESULTS

Epac1 and Epac2 proteins were expressed in villous CTB, STB, stroma, blood vessels and extravillous CTB of the placenta. Phe increased the expression of hCG alpha/beta mRNA and secretion of hCG protein in BeWo cells (P < 0.01 versus control). CPT-stimulated production of hCG (P < 0.05), albeit to a lesser extent than Phe. Progesterone production was also enhanced by Phe or CPT (P < 0.01 and P < 0.05, respectively). CPT or a stable cAMP analog (dibutyryl-cAMP: Db) increased the number of syncytialized BeWo cells (P < 0.01), whereas Phe did not stimulate fusion. CPT- or Db-induced syncytialization was observed, even in the presence of a PKA inhibitor. Knockdown of Epac1 or Rap1 repressed the Db-, CPT- or forskolin-induced cell fusion.

CONCLUSIONS

The Epac signaling pathway may be associated with the cAMP-mediated functional differentiation and syncytialization of human trophoblasts.

摘要

背景

单核绒毛细胞滋养层（CTB）分化并融合为多核合体滋养层（STB），后者产生 hCG 和孕激素。cAMP 介导的细胞内途径参与内分泌分化和融合（合胞体化）过程。cAMP 信号的直接激活交换蛋白（Epac）是 cAMP 信号的介质。我们研究了 Epac 和蛋白激酶 A（PKA）信号在滋养层衍生的 BeWo 细胞融合和分化中的差异作用。

方法

通过免疫组织化学检测 Epac1 和 Epac2 在人胎盘组织中的定位（n = 9）。用 PKA 选择性 cAMP 类似物（N（6）-苯-cAMP，Phe）或 Epac 选择性 cAMP 类似物（CPT）检测对 hCG 和孕激素产生以及 BeWo 细胞合胞体化的影响。评价 Epac 或其下游靶分子（Rap1）敲低对合胞体化的影响。

结果

Epac1 和 Epac2 蛋白在胎盘绒毛 CTB、STB、基质、血管和绒毛外 CTB 中表达。Phe 增加了 BeWo 细胞中 hCG alpha/beta mRNA 的表达和 hCG 蛋白的分泌（与对照组相比，P < 0.01）。CPT 刺激 hCG 的产生（P < 0.05），尽管程度低于 Phe。Phe 或 CPT 也增强了孕激素的产生（分别为 P < 0.01 和 P < 0.05）。CPT 或稳定的 cAMP 类似物（二丁酰-cAMP：Db）增加了合胞化的 BeWo 细胞数量（P < 0.01），而 Phe 则不能刺激融合。即使存在 PKA 抑制剂，也观察到 CPT 或 Db 诱导的合胞体化。Epac1 或 Rap1 的敲低抑制了 Db、CPT 或 forskolin 诱导的细胞融合。