Endothelial protein C receptor is increased in preterm preeclampsia and fetal growth restriction.

Placental dysfunction is the leading cause of both preeclampsia and fetal growth restriction. This study aimed to characterize endothelial protein C receptor (EPCR) in preterm preeclampsia, term preeclampsia, and fetal growth restriction (defined by delivery of a small for gestational age [SGA] infant [<10% birthweight centile]) and examine its regulation in primary syncytiotrophoblast. Placental EPCR mRNA and protein were significantly increased in patients with preterm preeclampsia (<34 weeks gestation) compared to gestation-matched controls (p < .0001). In the plasma, EPCR was also significantly elevated (p = .01) in established preterm preeclampsia while its substrate, protein C (PC) was significantly reduced (p = .0083). Placentas from preterm small for gestational age (SGA) cases, had elevated EPCR mRNA expression (p < .0001) relative to controls. At 36 weeks, no significant changes in plasma EPCR were detected in samples from patients destined to develop preeclampsia or deliver an SGA infant at term. In terms of syncytiotrophoblast, hypoxia significantly increased EPCR mRNA expression (p = .008), but Tumor Necrosis Factor Alpha (TNF-α) decreased EPCR mRNA. Interleukin-6 (IL-6) had no significant effect on EPCR mRNA expression. When isolated syncytiotrophoblast was treated with metformin under hypoxia (1% O2 ) or normoxia (8% O2 ), EPCR mRNA expression was significantly reduced (p = .008) relative to control. In conclusion, EPCR is markedly elevated in the placenta and the circulation of patients with established preterm preeclampsia and placental increases may be associated with hypoxia. Additionally, fetal growth-restricted pregnancies (as defined by the delivery of an SGA infant) also demonstrated elevated placental EPCR.

Placental growth factor is negatively regulated by epidermal growth factor receptor (EGFR) signaling.

INTRODUCTION: Preeclampsia is associated with reduced pro-angiogenic Placental Growth Factor (PlGF) and increased levels of anti-angiogenic soluble FMS like tyrosine kinase-1 (sFlt-1). We have previously shown that sFlt-1 secretion is positively regulated via the Epidermal Growth Factor Receptor (EGFR) and mitochondrial respiration pathways. We assessed whether these pathways also regulate endothelial and placental secretion of PlGF. METHODS: Primary cytotrophoblast cells and primary human umbilical vein endothelial cells (HUVECs) were treated with EGFR inhibitor gefitinib, or small molecules that inhibit down-stream pathways of the receptor: U0126, PD98059 (ERK/MEK pathway inhibitors), ZM336372 (JAK/STAT inhibitor) or AG490 (JAK inhibitor). We inhibited mitochondrial respiration in primary cytotrophoblasts using mitochondrial complex inhibitors rotenone (complex I), antimycin (complex III) or oligomycin (complex IV). We then measured PlGF secretion in the condition media. RESULTS: Three inhibitors of the EGFR pathway significantly increased PlGF secretion: gefitinib (p = 0.03), AG490 (p < 0.0001) and U0126 (p = 0.03) in primary cytotrophoblasts, while PD98059 reduced PlGF secretion (p = 0.002). In the same cells, neither gefitinib or UO126 altered PlGF mRNA expression, but AG490 significantly increased its expression (p = 0.02). Primary endothelial cell PlGF secretion was significantly reduced when treated with PD98059 and U0126 while ZM336372 had no effect. Rotenone significantly reduced cytotrophoblast PlGF secretion (p = 0.0005). Neither antimycin (p = 0.9) or oligomycin (p = 0.9) had an effect. DISCUSSION: We have shown that PlGF secretion from primary cytotrophoblast and HUVECs is altered by inhibiting EGFR signaling and potentially mitochondrial respiration, coincident with reduced sFlt-1 secretion. This suggests that common pathways are regulating both pro and anti-angiogenic molecules that are changed in association with preeclampsia and provides insight into the pathogenesis of this serious disease.

Circulating syndecan-1 is reduced in pregnancies with poor fetal growth and its secretion regulated by matrix metalloproteinases and the mitochondria.

Fetal growth restriction is a leading cause of stillbirth that often remains undetected during pregnancy. Identifying novel biomarkers may improve detection of pregnancies at risk. This study aimed to assess syndecan-1 as a biomarker for small for gestational age (SGA) or fetal growth restricted (FGR) pregnancies and determine its molecular regulation. Circulating maternal syndecan-1 was measured in several cohorts; a large prospective cohort collected around 36 weeks' gestation (n = 1206), a case control study from the Manchester Antenatal Vascular service (285 women sampled at 24-34 weeks' gestation); two prospective cohorts collected on the day of delivery (36 + 3-41 + 3 weeks' gestation, n = 562 and n = 405 respectively) and a cohort who delivered for preterm FGR (< 34 weeks). Circulating syndecan-1 was consistently reduced in women destined to deliver growth restricted infants and those delivering for preterm disease. Syndecan-1 secretion was reduced by hypoxia, and its loss impaired proliferation. Matrix metalloproteinases and mitochondrial electron transport chain inhibitors significantly reduced syndecan-1 secretion, an effect that was rescued by coadministration of succinate, a mitochondrial electron transport chain activator. In conclusion, circulating syndecan-1 is reduced among cases of term and preterm growth restriction and has potential for inclusion in multi-marker algorithms to improve detection of poorly grown fetuses.