Fu J-J, Lin P, Lv X-Y, Yan X-J, Wang H-X, Zhu C, Tsang B K, Yu X-G, Wang H
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China.
Placenta. 2009 Apr;30(4):305-12. doi: 10.1016/j.placenta.2009.01.005. Epub 2009 Feb 13.
Embryo implantation involves invasion of placental extravillous trophoblast cell (EVTs) into the uterus. Hyperactive EVT invasion occurs in hydatidiform moles and choriocarcinomas. We have previously demonstrated that the 20S proteasome is involved in mouse embryo implantation and its action is mediated via regulating the expression and activities of matrix metalloproteinase (MMP)-2 and MMP-9 in the EVTs. Our objective was to investigate whether low molecular mass polypeptide-2 (LMP2), a beta subunit of the 20S proteasome, is involved in the regulation of human trophoblast invasion. Normal human placentas or placentas from hydatidiform mole patients were collected and the expression of LMP2 in different cell types including trophoblastic column (TC), cytotrophoblast cells (CTB) and syncytiotrophoblast (STB) under different pathological states were studied by immunohistochemical analysis. Furthermore, the effect of LMP2 or proteasome on cell invasion was measured by using RNAi and inhibitors in a Matrigel invasion assay system in HTR-8/SVneo cells, a human invasive extravillous trophoblast cell line. Changes in the invasion-related molecules including MMP-2 and MMP-9 were also examined by using real time PCR and gelatin zymography. We demonstrated that the expression of LMP2 in TC of partial hydatidiform mole and complete hydatidiform mole, is higher than that in TC of normal human placentas. Besides, LMP2 knockdown significantly attenuated IL-1beta-induced cell invasion in vitro, a response readily induced by proteasome inhibitors. In summary, over-expression of the 20S proteasome beta-subunit LMP2 in trophoblast cells of hydatidiform moles may contribute to its highly invasive phenotype.
胚胎植入涉及胎盘绒毛外滋养层细胞（EVT）侵入子宫。EVT过度活跃的侵入发生在葡萄胎和绒毛膜癌中。我们之前已经证明20S蛋白酶体参与小鼠胚胎植入，其作用是通过调节EVT中基质金属蛋白酶（MMP）-2和MMP-9的表达及活性来介导的。我们的目的是研究20S蛋白酶体的β亚基低分子量多肽-2（LMP2）是否参与人类滋养层细胞侵入的调节。收集正常人类胎盘或葡萄胎患者的胎盘，通过免疫组织化学分析研究LMP2在不同病理状态下不同细胞类型（包括滋养层柱（TC）、细胞滋养层细胞（CTB）和合体滋养层（STB））中的表达。此外，在人侵袭性绒毛外滋养层细胞系HTR-8/SVneo细胞的基质胶侵袭试验系统中，使用RNA干扰和抑制剂来检测LMP2或蛋白酶体对细胞侵袭的影响。还通过实时PCR和明胶酶谱法检测包括MMP-2和MMP-9在内的侵袭相关分子的变化。我们证明，部分性葡萄胎和完全性葡萄胎的TC中LMP2的表达高于正常人类胎盘的TC。此外，LMP2基因敲低显著减弱了白细胞介素-1β诱导的体外细胞侵袭，蛋白酶体抑制剂很容易诱导这种反应。总之，葡萄胎滋养层细胞中20S蛋白酶体β亚基LMP2的过表达可能导致其高度侵袭性表型。
