The Department of Obstetrics and Gynaecology, Mercy Hospital for Women, University of Melbourne, 163 Studley Road, Heidelberg Victoria, 3084, Australia.
Mercy Perinatal, Mercy Hospital for Women, Victoria, Australia.
Reprod Biol Endocrinol. 2023 Jul 18;21(1):65. doi: 10.1186/s12958-023-01116-3.
Preeclampsia is a severe complication of pregnancy which is attributed to placental dysfunction. The retrotransposon, Paternal Expressed Gene 10 (PEG10) harbours critical placental functions pertaining to placental trophoblast cells. Limited evidence exists on whether PEG10 is involved in preeclampsia pathogenesis. This study characterised the expression and regulation of PEG10 in placentas from patients with early-onset preeclampsia compared to gestation-matched controls.
PEG10 expression was measured in plasma and placentas collected from patients with early-onset preeclampsia (< 34 weeks') and gestation-matched controls using ELISA (protein) and RT-qPCR (mRNA). First-trimester human trophoblast stem cells (hTSCs) were used for in vitro studies. PEG10 expression was measured during hTSC differentiation and hTSC exposure to hypoxia (1% O) and inflammatory cytokines (IL-6 and TNFα) using RT-qPCR. Functional studies used PEG10 siRNA to measure the effect of reduced PEG10 on canonical TGF-[Formula: see text] signalling and proliferation using luciferase and xCELLigence assays, respectively.
PEG10 mRNA expression was significantly reduced in placentas from patients with early-onset preeclampsia (< 34 weeks' gestation) relative to controls (p = 0.04, n = 78 vs n = 18 controls). PEG10 protein expression was also reduced in preeclamptic placentas (p = 0.03, n = 5 vs n = 5 controls, blinded assessment of immunohistochemical staining), but neither PEG10 mRNA nor protein could be detected in maternal circulation. PEG10 was most highly expressed in hTSCs, and its expression was reduced as hTSCs differentiated into syncytiotrophoblasts (p < 0.0001) and extravillous trophoblasts (p < 0.001). Trophoblast differentiation was not altered when hTSCs were treated with PEG10 siRNA (n = 5 vs n = 5 controls). PEG10 was significantly reduced in hTSCs exposed to hypoxia (p < 0.01). PEG10 was also reduced in hTSCs treated with the inflammatory cytokine TNF [Formula: see text] (p < 0.01), but not IL-6. PEG10 knocked down (siRNA) in hTSCs showed reduced activation of the canonical TGF-β signalling effector, the SMAD binding element (p < 0.05) relative to controls. PEG10 knockdown in hTSCs however was not associated with any significant alterations in proliferation.
Placental PEG10 is reduced in patients with early-onset preeclampsia. In vitro studies suggest that hypoxia and inflammation may contribute to PEG10 downregulation. Reduced PEG10 alters canonical TGF-[Formula: see text] signalling, and thus may be involved in trophoblast dysfunction associated with this pathway.
子痫前期是一种严重的妊娠并发症，其与胎盘功能障碍有关。反转录转座子父源表达基因 10（PEG10）具有与胎盘滋养层细胞有关的关键胎盘功能。目前关于 PEG10 是否参与子痫前期发病机制的证据有限。本研究旨在比较早发型子痫前期（<34 周）患者与妊娠匹配对照者胎盘内 PEG10 的表达和调控。
采用 ELISA（蛋白）和 RT-qPCR（mRNA）法检测早发型子痫前期（<34 周）患者和妊娠匹配对照者血浆和胎盘内 PEG10 的表达。采用人早孕滋养层干细胞（hTSC）进行体外研究。采用 RT-qPCR 法检测 hTSC 分化过程中以及 hTSC 暴露于低氧（1% O2）和炎症细胞因子（IL-6 和 TNFα）时 PEG10 的表达。采用 PEG10 siRNA 进行功能研究，以评估降低 PEG10 对经典 TGF-β 信号转导和增殖的影响，分别采用荧光素酶和 xCELLigence 检测。
早发型子痫前期患者（<34 周妊娠）胎盘内 PEG10 mRNA 表达明显低于对照组（p=0.04，n=78 对 n=18 例对照）。子痫前期患者胎盘内 PEG10 蛋白表达也降低（p=0.03，n=5 对 n=5 例对照，免疫组化染色的盲法评估），但母体外周血中均无法检测到 PEG10。PEG10 在 hTSC 中表达最高，随着 hTSC 分化为合体滋养层细胞（p<0.0001）和细胞滋养层细胞外突（p<0.001），其表达减少。当用 PEG10 siRNA 处理 hTSC 时，滋养层分化没有改变（n=5 对 n=5 例对照）。hTSC 暴露于低氧时 PEG10 显著减少（p<0.01）。hTSC 用炎症细胞因子 TNFα 处理时 PEG10 也减少（p<0.01），但 IL-6 则没有。与对照组相比，hTSC 中的 PEG10 敲低（siRNA）与经典 TGF-β 信号转导效应物 SMAD 结合元件的活性降低有关（p<0.05）。然而，hTSC 中 PEG10 的敲低与增殖无明显相关性。
早发型子痫前期患者胎盘内 PEG10 减少。体外研究表明，低氧和炎症可能导致 PEG10 下调。减少的 PEG10 改变了经典的 TGF-β 信号转导，因此可能与该途径相关的滋养层功能障碍有关。
