HIF1 inhibitor acriflavine rescues early-onset preeclampsia phenotype in mice lacking placental prolyl hydroxylase domain protein 2
Julien Sallais, Chanho Park, Sruthi Alahari, Tyler Porter, Ruizhe Liu, Merve Kurt, Abby Farrell, Martin Post, Isabella Caniggia
Julien Sallais, Chanho Park, Sruthi Alahari, Tyler Porter, Ruizhe Liu, Merve Kurt, Abby Farrell, Martin Post, Isabella Caniggia
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Research Article Development Reproductive biology

HIF1 inhibitor acriflavine rescues early-onset preeclampsia phenotype in mice lacking placental prolyl hydroxylase domain protein 2

Abstract

Preeclampsia is a serious pregnancy disorder that lacks effective treatments other than delivery. Improper sensing of oxygen changes during placentation by prolyl hydroxylases (PHDs), specifically PHD2, causes placental hypoxia-inducible factor-1 (HIF1) buildup and abnormal downstream signaling in early-onset preeclampsia, yet therapeutic targeting of HIF1 has never been attempted. Here we generated a conditional (placenta-specific) knockout of Phd2 in mice (Phd2–/– cKO) to reproduce HIF1 excess and to assess anti-HIF therapy. Conditional deletion of Phd2 in the junctional zone during pregnancy increased placental HIF1 content, resulting in abnormal placentation, impaired remodeling of the uterine spiral arteries, and fetal growth restriction. Pregnant dams developed new-onset hypertension at midgestation (E9.5) in addition to proteinuria and renal and cardiac pathology, hallmarks of severe preeclampsia in humans. Daily injection of acriflavine, a small molecule inhibitor of HIF1, to pregnant Phd2–/– cKO mice from E7.5 (prior to hypertension) or E10.5 (after hypertension had been established) to E14.5 corrected placental dysmorphologies and improved fetal growth. Moreover, it reduced maternal blood pressure and reverted renal and myocardial pathology. Thus, therapeutic targeting of the HIF pathway may improve placental development and function, as well as maternal and fetal health, in preeclampsia.

Authors

Julien Sallais, Chanho Park, Sruthi Alahari, Tyler Porter, Ruizhe Liu, Merve Kurt, Abby Farrell, Martin Post, Isabella Caniggia

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Figure 1

Deletion of Phd2 in JZ layer increases placental HIF1A content and activity.

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Deletion of Phd2 in JZ layer increases placental HIF1A content and activ...
(A) IHC staining for PHD2 (top panel, scale bars = 500 μm) and Tpbpa (bottom panel, scale bars = 100 μm) in WT and Phd2–/– cKO placental sections at E14.5 (n = 3 WT and Phd2–/– cKO placentae, respectively). (B) Immunofluorescence (IF) staining for GFP (marks Cre recombinase expression) in sections from WT and Phd2–/– cKO placentae at E14.5 (n = 3 WT and Phd2–/– cKO placentae respectively; all scale bars represent 45 μm). (C) Quantitative PCR (qPCR) for Phd2 in E14.5 WT and Phd2–/– cKO placentae (Phd2, ***P < 0.001 relative to WT, unpaired Student’s t test, n = 16 WT, n = 18 Phd2–/– cKO placentae). (D) Representative Western blot (WB) for PHD2, HIF1A, and HIF2A and associated densitometry in whole placental lysates from WT and Phd2–/– cKO placentae (PHD2, **P < 0.01 relative to WT, unpaired Student’s t test, n = 15 WT and n = 16 Phd2–/– cKO placentae; HIF1A, ***P < 0.001 relative to WT, unpaired Student’s t test, n = 14 WT and n = 16 Phd2–/– cKO placentae; HIF2A, no significant difference relative to WT, n = 8 WT and n = 10 Phd2–/– cKO placentae; bottom panel HIF2A and ACTB lanes were run on the same gel but were noncontiguous). (E) IHC staining for HIF1A and HIF2A in placenta sections from WT and Phd2–/– cKO placentae at E14.5 (n = 3 WT and Phd2–/– cKO placentae respectively, scale bar = 50 μm). (F) Lactate content measured by tandem mass spectrometry in E14.5 WT and Phd2–/– cKO placentae (*P < 0.05 compared to WT, unpaired Student’s t test, n =11 WT and n = 18 Phd2–/– cKO placentae). (G) qPCR for Vegfa and Hyou1 in E14.5 WT and Phd2–/– cKO placentae (*P < 0.05 compared with WT, unpaired Student’s t test; Vegfa, n = 12 WT and n = 13 Phd2–/– cKO placentae; Hyou1, n = 13 WT and n = 14 Phd2–/– cKO placentae). Data are expressed as fold change, relative to the 18S. D, decidua; JZ, junctional zone; L, labyrinth; WT, wild-type; cKO, conditional knockout.