腎上腺髓素調控人類胎盤細胞之入侵能力

Abstract

在懷孕初期，人類絨毛外滋養層細胞入侵到母體子宮內膜是胎盤發育的關鍵作用。人類胎盤專一性轉錄因子glia cell missing 1 (GCM1)具有調控滋養層細胞分化及融合的能力，我們之前透過染色質免疫沉澱結合晶片分析技術鑑定HtrA4及SYDE1為GCM1目標基因，GCM1藉由轉錄活化HtrA4及SYDE1的基因表現來促進滋養層細胞的入侵能力。在最近的分析中鑑定了Adrenomedullin (ADM)可作為GCM1新的目標基因，已知此胜肽為降鈣素基因相關胜肽超級家族的成員之一，並廣泛表現在人類的生殖系統中。為了進一步了解人類絨毛外滋養層細胞的入侵機制，我們進行實驗探討GCM1是否也可通過調控ADM的表現來影響胎盤細胞的侵襲能力。在細胞入侵試驗中，利用內生性GCM1及ADM含量較低的JAR細胞株經由ADM處理後可促進細胞之入侵能力；相反使用內生性GCM1及ADM含量較高的BeWo細胞株，阻斷ADM的表現後會抑制細胞的入侵能力。更進一步發現ADM可調控TG2在胎盤細胞的表現，同時藉由調控TG2來影響胎盤細胞的入侵能力。除此之外，利用多西環素誘導JAR穩定表現ADM細胞株與T-HESC子宮內膜細胞進行共同培養試驗後發現，在細胞中大量持續表現ADM可促使胎盤細胞的移行能力。綜合上述結果，本研究證實在胎盤的發育過程中，GCM1可藉由調控ADM的表現來影響胎盤細胞的入侵能力，以及促進胎盤細胞與子宮內膜細胞之間的交互作用。

Invasion of human extravillous trophoblast (EVT) into the maternal endometrium in the early stages of pregnancy is a crucial process of placental development. Human glia cell missing 1 (GCM1) is placenta-specific transcription factor, which plays important roles in regulation of trophoblast differentiation and fusion. Our recent ChIP-chip experiments have demonstrated that GCM1 promotes trophoblast cell invasion via transactivation of HtrA4 and SYDE1 gene expression. Along this line, we have identified adrenomedullin (ADM) as a potential GCM1 target gene. ADM belongs to the calcitonin gene related peptide (CGRP) superfamily, and is widely expressed in human reproductive tissues. To better understand the mechanism of EVT invasion, we studied whether GCM1 also regulates placental cell invasion through ADM. In cell invasion assay, we observed that treatment with ADM significantly enhanced the invasion activity of placental JAR cells, which exhibit low endogenous levels of GCM1 and ADM. In contrast, ADM-knockdown suppressed the invasion activity of placental BeWo cells, which exhibit high endogenous levels of GCM1 and ADM. Furthermore, we demonstrated ADM may stimulate plascental cell invasion through upregulation of transglutaminase 2 (TG2) expression. By co-culture of tetracycline-inducible ADM-expressing JAR cells with decidualized T-HESC monolayer, we also demonstrated enhanced ADM-mediated JAR cell migration in the presence of doxycycline. Our study reveals a novel GCM1-ADM axis in regulation of trophoblast cell invasion and trophoblast-decidual cell interaction during placental development.