Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.
Hum Reprod. 2011 May;26(5):1025-34. doi: 10.1093/humrep/der053. Epub 2011 Mar 15.
Severe pre-eclampsia (sPE) causes significant maternal morbidity and intrauterine growth restriction as a result of severe placental dysfunction. Defects in the formation of both extra-villous and villous trophoblast are characteristic of this disease. The outer syncytiotrophoblast layer covering the placental villi develops syncytial knots and focal necrosis while reduced invasion of the extra-villous trophoblast results in a reduced maternal blood supply and ischemia of the placental villi. The transcription factor glial cell missing-1 (GCM1) regulates formation of both types of trophoblast. GCM1 expression is reduced in placental villi of women with sPE but the functional downstream consequences of reduced GCM1 expression are unknown.
In floating first trimester villous explants we demonstrated increased mRNA (2.5-fold, n = 12) and protein level (9.8-fold) of tissue inhibitor of metalloproteinase-4 (TIMP4) following repression of GCM1 (70 ± 7%) by small interfering-RNA, using RT-PCR and western blot, respectively. Similar increases in TIMP4 mRNA (4.2-fold, n = 7, P< 0.001 versus control) and protein levels were found following gene silencing of GCM1 in BeWo cells (<90% knock down of protein). TIMP4 protein was increased in placenta from women with sPE (3.5 ± 0.4 pg/µg, n = 8), compared with preterm (1.7 ± 0.17 pg/µg, n = 9) and term controls (1.6 ± 0.16 pg/µg, n = 9; P< 0.01; quantified by enzyme-linked immunosorbent assay and visualized using immunohistochemistry) with reduced GCM1 expression, mostly in the pathologic syncytial knots.
TIMP4 is a downstream target of GCM1 that may link the consequences of reduced GCM-1-directed trophoblast differentiation to histologic and functional components of disordered placentation in sPE.
严重子痫前期（sPE）会导致严重的胎盘功能障碍，从而导致母体发病率增加和宫内生长受限。这种疾病的特征是绒毛外和绒毛滋养层的形成缺陷。覆盖胎盘绒毛的外层合胞滋养层形成合胞体结节和局灶性坏死，而绒毛外滋养层的侵袭减少会导致母体血液供应减少和胎盘绒毛缺血。胶质细胞缺失 1（GCM1）转录因子调节两种滋养层的形成。sPE 妇女胎盘绒毛中 GCM1 的表达减少，但减少的 GCM1 表达的功能下游后果尚不清楚。
在漂浮的第一孕期绒毛外植体中，我们通过 RT-PCR 和 Western blot 分别证明，用小干扰 RNA 抑制 GCM1（70±7%）后，基质金属蛋白酶组织抑制剂 4（TIMP4）的 mRNA（2.5 倍，n=12）和蛋白水平（9.8 倍）增加。在 BeWo 细胞中基因沉默 GCM1 后也发现了类似的 TIMP4 mRNA（4.2 倍，n=7，P<0.001 与对照相比）和蛋白水平增加（蛋白减少<90%）。与早产（1.7±0.17pg/µg，n=9）和足月对照组（1.6±0.16pg/µg，n=9相比，sPE 妇女胎盘的 TIMP4 蛋白增加（3.5±0.4pg/µg，n=8）；n=9；P<0.01；通过酶联免疫吸附试验定量，免疫组织化学染色可视化）与 GCM1 表达减少有关，主要是在病理性合胞体结节中。
TIMP4 是 GCM1 的下游靶标，它可能将减少的 GCM1 指导的滋养层分化与 sPE 中紊乱的胎盘形成的组织学和功能成分联系起来。
