Oxygen regulation of aquaporin-4 in human placenta

NATALIA SZPILBARG; ABRIL SEYAHIAN ; MAURICIO DI PAOLA; MAURICIO CASTRO-PARODI; NORA MARTINEZ; MARIANA FARINA; ALICIA E DAMIANO

REPRODUCTIVE BIOMEDICINE ONLINE

REPRODUCTIVE HEALTHCARE LTD

Lugar: Amsterdam; Año: 2018

1472-6483

Research question: 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.Design: 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 CoCl2. 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.Results: 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 CoCl2, that stabilizes hypoxia inducible factor (HIF)-1, also increased AQP4 levels. In-silico analysis showed three putative binding sites for HIF-1in AQP4 promotor.