Somers G R, Bradbury R, Trute L, Conigrave A, Venter D J
Department of Pathology and Early Detection Laboratory, Peter MacCallum Cancer Institute, East Melbourne, Victoria, Australia.
Lab Invest. 1999 Feb;79(2):131-9.
The P2Y family of purinergic receptors are members of the G-protein-coupled receptor superfamily. The P2Y6 subtype is expressed at particularly high levels in the placenta, suggesting that P2Y6 plays an important role in placental function. However, the cellular localization of P2Y6 within the placenta is unknown. This study examined the expression of P2Y6 in first-trimester and full-term placental tissues, as well as examples of gestational trophoblastic disease, by Northern blot analysis and in situ hybridization. P2Y6 message was present at similar levels in first-trimester and full-term placenta, and in situ hybridization revealed that message was most abundant in the cytotrophoblast of the villi and chorionic plate at both gestational stages. The syncytiotrophoblast harbored lower levels of P2Y6 in first-trimester placenta, and by full-term, the syncytiotrophoblast only focally expressed P2Y6 transcripts. Neither the intermediate trophoblast nor nontrophoblastic elements of the placenta expressed P2Y6. Molar disease expressed P2Y6 in the villous trophoblast but not in the proliferative intermediate trophoblast, recapitulating the pattern of first-trimester placenta. Neither choriocarcinoma nor the choriocarcinoma cell lines JEG-3 and JAr expressed P2Y6 transcript. These findings reveal that P2Y6 mRNA production is highly characteristic of the epithelial-like cytotrophoblast and syncytiotrophoblast, whereas expression is absent in the mesenchymal-like intermediate trophoblast. Thus, P2Y6 may play an important role in trophoblastic development, differentiation, and neoplasia.
嘌呤能受体的P2Y家族是G蛋白偶联受体超家族的成员。P2Y6亚型在胎盘中表达水平特别高，这表明P2Y6在胎盘功能中起重要作用。然而，P2Y6在胎盘内的细胞定位尚不清楚。本研究通过Northern印迹分析和原位杂交检测了孕早期和足月胎盘组织以及妊娠滋养细胞疾病实例中P2Y6的表达。P2Y6信息在孕早期和足月胎盘中的水平相似，原位杂交显示在两个妊娠阶段，绒毛和绒毛膜板的细胞滋养层中该信息最为丰富。合体滋养层在孕早期胎盘中P2Y6水平较低，到足月时，合体滋养层仅局灶性表达P2Y6转录本。胎盘的中间滋养层和非滋养层成分均不表达P2Y6。葡萄胎在绒毛滋养层中表达P2Y6，但在增殖性中间滋养层中不表达，重现了孕早期胎盘的模式。绒毛膜癌以及绒毛膜癌细胞系JEG-3和JAr均不表达P2Y6转录本。这些发现表明，P2Y6 mRNA的产生是上皮样细胞滋养层和合体滋养层的高度特征，而在间充质样中间滋养层中不存在表达。因此，P2Y6可能在滋养层发育、分化和肿瘤形成中起重要作用。
