Laboratorio de Biología de la Reproducción, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO)- CONICET- Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155 (1121) Buenos Aires, Argentina.
Laboratorio de Biología de la Reproducción, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO)- CONICET- Facultad de Medicina, Universidad de Buenos Aires. Paraguay 2155 (1121) Buenos Aires, Argentina; Cátedra de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Junín 956 (1113) Buenos Aires, Argentina.
Reprod Biomed Online. 2018 Nov;37(5):601-612. doi: 10.1016/j.rbmo.2018.08.015. Epub 2018 Oct 6.
We recently reported that blocking of placental aquaporins (AQP) abrogates the apoptotic response of the trophoblast. As trophoblast apoptosis is exacerbated in pre-eclampsia, we hypothesized that changes in AQP in these placentae may trigger programmed cell death. We analysed AQP4 expression in pre-eclamptic placentae and its regulation by oxygen tension.
AQP4 expression was studied in placentae from non-pathological and pre-eclamptic pregnancies by reverse transcription polymerase chain reaction (RT-PCR), Western blot, immunofluorescence and immunohistochemistry. Explants from non-pathological placentae were cultured in normoxia, hypoxia, hypoxia-reoxygenation and CoCl. AQP4 expression was investigated by RT-PCR and Western blot. Hypoxia responsive elements sites on AQP4 promotor were investigated by in-silico analysis. AQP4 degradation was studied in the presence of proteosomal and lysosomal inhibitors.
AQP4 protein expression was weakly detectable in pre-eclamptic placentae, but its mRNA was elevated compared with non-pathological placentae. In non-pathological explants cultured in hypoxia, AQP4 mRNA and protein were increased compared with placentae cultured in ambient oxygen but decreased after reoxygenation. Incubation with CoCl, that stabilizes hypoxia inducible factor (HIF)-1α, also increased AQP4 levels. In-silico analysis showed three putative binding sites for HIF-1α in AQP4 promotor.
Oxygen may regulate AQP4 expression in human placenta, possibly through HIF-1α. Therefore, the decrease in AQP4 throughout pregnancy, previously reported, is consistent with changes in HIF-1α, and suggests that AQP4 might have a crucial role during placentation. Therefore, the abnormal expression of AQP4 may be involved in the cause of pre-eclampsia, but it does not seem to take part in the apoptotic events.
我们最近报道称，胎盘水通道蛋白（AQP）的阻断可消除滋养细胞的凋亡反应。由于子痫前期中滋养细胞凋亡加剧，我们假设这些胎盘中 AQP 的变化可能触发程序性细胞死亡。我们分析了子痫前期胎盘的 AQP4 表达及其氧张力调节。
通过逆转录聚合酶链反应（RT-PCR）、Western blot、免疫荧光和免疫组化分析非病理性和子痫前期胎盘的 AQP4 表达。非病理性胎盘的外植体在常氧、缺氧、缺氧复氧和 CoCl 中培养。通过 RT-PCR 和 Western blot 研究 AQP4 表达。通过计算机分析研究 AQP4 启动子上的缺氧反应元件位点。在存在蛋白酶体和溶酶体抑制剂的情况下研究 AQP4 降解。
AQP4 蛋白在子痫前期胎盘的表达较弱，但与其相比，其 mRNA 升高。在常氧培养的非病理性外植体中，AQP4 mRNA 和蛋白较在大气氧中培养的胎盘增加，但复氧后减少。用 CoCl 孵育可稳定缺氧诱导因子（HIF）-1α，也增加了 AQP4 水平。计算机分析显示 AQP4 启动子上有三个可能与 HIF-1α 结合的位点。
氧可能通过 HIF-1α调节人胎盘的 AQP4 表达。因此，先前报道的整个妊娠期间 AQP4 的减少与 HIF-1α 的变化一致，这表明 AQP4 在胎盘形成过程中可能具有重要作用。因此，AQP4 的异常表达可能与子痫前期的病因有关，但它似乎不参与凋亡事件。
