CD74-Downregulation of Placental Macrophage-Trophoblastic Interactions in Preeclampsia.

RATIONALE: We hypothesized that cluster of differentiation 74 (CD74) downregulation on placental macrophages, leading to altered macrophage-trophoblast interaction, is involved in preeclampsia. OBJECTIVE: Preeclamptic pregnancies feature hypertension, proteinuria, and placental anomalies. Feto-placental macrophages regulate villous trophoblast differentiation during placental development. Disturbance of this well-balanced regulation can lead to pathological pregnancies. METHODS AND RESULTS: We performed whole-genome expression analysis of placental tissue. CD74 was one of the most downregulated genes in placentas from preeclamptic women. By reverse transcriptase-polymerase chain reaction, we confirmed this finding in early-onset (<34 gestational week, n=26) and late-onset (≥34 gestational week, n=24) samples from preeclamptic women, compared with healthy pregnant controls (n=28). CD74 protein levels were analyzed by Western blot and flow cytometry. We identified placental macrophages to express CD74 by immunofluorescence, flow cytometry, and RT-PCR. CD74-positive macrophages were significantly reduced in preeclamptic placentas compared with controls. CD74-silenced macrophages showed that the adhesion molecules ALCAM, ICAM4, and Syndecan-2, as well as macrophage adhesion to trophoblasts were diminished. Naive and activated macrophages lacking CD74 showed a shift toward a proinflammatory signature with an increased secretion of tumor necrosis factor-α, chemokine (C-C motif) ligand 5, and monocyte chemotactic protein-1, when cocultured with trophoblasts compared with control macrophages. Trophoblasts stimulated by these factors express more CYP2J2, sFlt1, TNFα, and IL-8. CD74-knockout mice showed disturbed placental morphology, reduced junctional zone, smaller placentas, and impaired spiral artery remodeling with fetal growth restriction. CONCLUSIONS: CD74 downregulation in placental macrophages is present in preeclampsia. CD74 downregulation leads to altered macrophage activation toward a proinflammatory signature and a disturbed crosstalk with trophoblasts.

The association of single nucleotide polymorphisms of the maternal cystathionine-ß-synthase gene with early-onset preeclampsia.

OBJECTIVES: Preeclampsia (PE) is a pregnancy complication, characterized by hypertension and proteinuria. The transsulfuration pathway may be involved in its pathophysiology, since homocysteine, cystathionine and cysteine are increased in PE. Cystathionine-ß-synthase (CBS) is a key-enzyme in the pathway, converting homocysteine into cysteine via cystathionine. Another product of CBS is hydrogen sulfide (H2S), a vasodilatory, proangiogenic and cytoprotective gas that is thought to play a role in placental and vascular function during pregnancy. Since single nucleotide polymorphisms (SNPs) can affect CBS expression and/or function, we studied tag-SNPs in the CBS gene in PE patients. STUDY DESIGN: Controls (n=75), early-onset (n=45), and late-onset PE (n=52) cases were genotyped for six tag-SNPs in the CBS gene; rs12329764, rs2851391, rs234713, rs234706, rs1789953, and rs11203172. Plasma homocysteine, cysteine and cystathionine were determined during pregnancy. MAIN OUTCOME MEASURES: Early-onset PE, late-onset PE. RESULTS: Women with the minor allele of rs11203172 have a reduced risk for early-onset PE. Compared to women without the minor allele, normotensive pregnant women with the minor allele of rs11203172 and rs234713 have lower cysteine levels. Women with the minor allele of rs1789953 have increased levels of cysteine and cystathionine, compared to women without. CONCLUSION: The CBS tag-SNP rs11203172 is associated with a decreased risk for early-onset PE. Decreased cysteine concentrations in normotensive pregnant women carrying the minor allele of rs11203172, may be due to increased cysteine conversion to H2S by CBS. Higher H2S levels may positively affect placentation and vascular function during pregnancy and decrease their risk for PE.

OP008. Different dysregulation of placental mirnas in early- and late-onset preeclampsia.

INTRODUCTION: miRNAs are small ∼22nt RNAs, important in the fine-tuning of mRNA in many organs including placenta. Preeclampsia (PE) is a heterogenous disease which may be divided into early-onset PE, which is a more severe form with assumed placental origin, and late-onset PE, with assumed maternal origin. OBJECTIVES: The aim of this study was to investigate the differential expression of miRNAs in early and late-onset PE compared to controls using high throughput sequencing. METHODS: Placentas were obtained from an ongoing biobank collection at Oslo University Hospital. 23 normotensive controls, 23 early-onset PE (delivery at gestational week <34) and 26 late-onset PE (week⩾34) samples were sequenced using Illumina sequencing technology. Differential expressed miRNAs were identified by the EdgeR package in R and predicted targets were estimated by miRWalk. RESULTS: 3 placental miRNAs were differentially expressed between controls and late-onset PE, 4 miRNAs were differentially expressed between early- and late-onset PE and 51 miRNAs were differentially expressed between early-onset PE and controls. Combining with mRNA array data from a subgroup of the same patients, we identified predicted targets of some of these miRNAs with significant inverse correlation between the respective mRNAs/miRNAs. CONCLUSION: These preliminary results suggest that miRNAs in placenta could be more important in the dysregulation of mRNAs in early-onset PE than in late-onset of the disease.

Activation of LXR increases acyl-CoA synthetase activity through direct regulation of ACSL3 in human placental trophoblast cells.

Placental fatty acid transport and metabolism are important for proper growth and development of the feto-placental unit. The nuclear receptors, liver X receptors alpha and beta (LXRalpha and LXRbeta), are key regulators of lipid metabolism in many tissues, but little is known about their role in fatty acid transport and metabolism in placenta. The current study investigates the LXR-mediated regulation of long-chain acyl-CoA synthetase 3 (ACSL3) and its functions in human placental trophoblast cells. We demonstrate that activation of LXR increases ACSL3 expression, acyl-CoA synthetase activity, and fatty acid uptake in human tropholast cells. Silencing of ACSL3 in these cells attenuates the LXR-mediated increase in acyl-CoA synthetase activity. Furthermore, we show that ACSL3 is directly regulated by LXR through a conserved LXR responsive element in the ACSL3 promoter. Our results suggest that LXR plays a regulatory role in fatty acid metabolism by direct regulation of ACSL3 in human placental trophoblast cells.

Circulating and placental growth-differentiation factor 15 in preeclampsia and in pregnancy complicated by diabetes mellitus.

Growth-differentiation factor 15 (GDF-15), a stress-responsive transforming growth factor-beta-related cytokine, is emerging as a new risk marker in patients with cardiovascular disease. We explored GDF-15 in preeclampsia and in diabetic pregnancies, because these conditions are associated with augmented risk for cardiovascular disease, both in mother and in offspring. Plasma from pregnant women (n=267; controls: n=59, preeclampsia: n=85, diabetes mellitus: n=112, and superimposed preeclampsia in diabetes mellitus: n=11), fetal plasma (n=72), and amniotic fluid (n=99) were analyzed by immunoassay for GDF-15. Placental GDF-15 mRNA and protein expression levels were analyzed by quantitative real-time PCR and immunoblots in 78 and 18 pregnancies, respectively. Conditioned media from preeclamptic (n=6) and control (n=6) villous placenta explants were analyzed by immunoassay for GDF-15. Median maternal GDF-15 concentration was elevated in those with diabetes mellitus, as compared with controls (91 549 versus 79 875 ng/L; P=0.02). Median GDF-15 concentration was higher in patients with preeclampsia than in controls in term maternal blood samples (127 061 versus 80 319 ng/L; P<0.001). In the fetal circulation and amniotic fluid, GDF-15 was elevated in preeclampsia and superimposed preeclampsia in diabetes mellitus, as compared with controls. GDF-15 placental mRNA expression was elevated in preeclampsia, as compared with controls (P=0.002). Placenta immunoblots confirmed a single GDF-15 protein band, and a time-dependent increase in GDF-15 protein was detected in the conditioned media. Our study is the first to show that GDF-15 is dysregulated, both in preeclampsia and in diabetic pregnancies. The mechanisms and diagnostic implications of these findings remain to be explored.