Department of Physiology, Obstetrics and Gynecology and Medicine, University of Toronto, Toronto, Canada.
Reprod Sci. 2010 Sep;17(9):833-43. doi: 10.1177/1933719110373147. Epub 2010 Jul 8.
Urocortin 2 (Ucn2) and urocortin 3 (Ucn3) are new members of the corticotrophin-releasing hormone (CRH) family of peptides expressed and localized in human placenta. In the current study, we aimed to asses whether hypoxia affects placental Ucn2/Ucn3 messenger RNA (mRNA) expression and protein localization in physiological or pathological hypoxia and to evaluate whether the effect is modulated by the hypoxia-inducible factor 1alpha (HIF-1alpha).
Early first-trimester placental specimens from elective termination of pregnancy were used for villous explants and term placental tissue were used for primary cell cultures. The samples were incubated under different oxygen conditions; parallel sets exposed to hypoxia re-oxygenation (HR). Dimethyloxalylglycine (DMOG), an HIF-1alpha stabilizer, was used to mimic the effects of hypoxia in villous explants. Real-time polymerase chain reaction (PCR) and immunohystochemistry were performed on early pregnancy and preeclamptic (PE) placentae. mRNA levels were measured on villous explants and cell cultures incubated under different oxygen and reagent conditions.
Both Ucn2 and Ucn3 mRNA expression was significantly higher at 6 to 9 weeks of gestation than 10 to 12 wks and in primary trophoblast cell cultures and explants exposed to low O(2) tension (3%) compared to 20% O(2). Strong Ucn2/Ucn3 immunoreactivity was present in trophoblast villi from 6 weeks placentae. Ucn2 immunostaining was stronger in early PE (E-PE) samples relative to controls whereas Ucn3 showed stronger immunoreactivity in late-PE (L-PE) placentae. Only Ucn2 transcript levels increased in HR explants. Ucn2 and Ucn3 expression by first-trimester explants was significantly greater in the presence of DMOG. All PE placentae expressed significantly higher Ucn2 and Ucn3 mRNA compared to controls.
Placental Ucn2 and Ucn3 expression is sensitive to O(2) tensions and mediated by HIF-1alpha. During early pregnancy, Ucn2/Ucn3 may influence trophoblast proliferation and establishment of pregnancy. In PE placentae, the increased expression of both peptides may reflect a response to the oxidative stress.
尿皮质素 2（Ucn2）和尿皮质素 3（Ucn3）是新的促肾上腺皮质激素释放激素（CRH）家族肽，在人胎盘内表达和定位。在本研究中，我们旨在评估低氧是否影响生理或病理低氧条件下胎盘 Ucn2/Ucn3 信使 RNA（mRNA）表达和蛋白定位，并评估这种影响是否受缺氧诱导因子 1alpha（HIF-1alpha）调节。
采用选择性终止妊娠的早期第一孕期胎盘标本进行绒毛外植体和足月胎盘组织的原代细胞培养。将标本在不同的氧条件下孵育；平行组进行缺氧再氧合（HR）。二甲氧酰基甘氨酸（DMOG），一种 HIF-1alpha 稳定剂，用于模拟绒毛外植体中的低氧效应。对早孕期和子痫前期（PE）胎盘进行实时聚合酶链反应（PCR）和免疫组织化学分析。在不同的氧和试剂条件下孵育绒毛外植体和细胞培养物，测量 mRNA 水平。
Ucn2 和 Ucn3 mRNA 表达在 6 至 9 孕周时明显高于 10 至 12 孕周，在低氧张力（3%）下暴露于低氧张力（3%）的绒毛外植体和原代滋养层细胞培养物中明显高于 20%O2。6 周胎盘滋养层绒毛中存在强烈的 Ucn2/Ucn3 免疫反应性。与对照组相比，早期 PE（E-PE）样本中 Ucn2 免疫染色强度更强，而晚期 PE（L-PE）胎盘 Ucn3 免疫反应性更强。仅 HR 外植体中的 Ucn2 转录水平增加。DMOG 存在时，第一孕期外植体的 Ucn2 和 Ucn3 表达显著增加。与对照组相比，所有 PE 胎盘的 Ucn2 和 Ucn3 mRNA 表达均显著升高。
胎盘 Ucn2 和 Ucn3 表达对 O2 张力敏感，并受 HIF-1alpha 调节。在妊娠早期，Ucn2/Ucn3 可能影响滋养层细胞的增殖和妊娠的建立。在 PE 胎盘，两种肽的表达增加可能反映了对氧化应激的反应。
