Higher decidual EBI3 and HLA-G mRNA expression in preeclampsia: Cause or consequence of preeclampsia.

The maternal immune system must adapt to tolerate the invasion of the allogeneic feto-placental unit. It is generally accepted that improper adaptation causes pregnancy complications like preeclampsia. The Epstein-Barr virus-induced gene 3 (EBI3) protein is a subunit of immune-modulatory cytokines interleukin 27 (IL-27) and IL-35. EBI3 has been reported to associate with HLA-G. In this small pilot study we find higher decidual EBI3 (p<0.05) and HLA-G (p<0.01) mRNA expression in preeclampsia (n=7) compared to normotensive (n=8) pregnancies. Whether the higher EBI3 and HLA-G mRNA expression is a consequence or cause of preeclampsia remains to be answered. Further research to determine the effects on IL-27 and IL-35 is needed.

Placental expression of heparan sulfate 3-O-sulfotransferase-3A1 in normotensive and pre-eclamptic pregnancies.

INTRODUCTION: The endothelial glycocalyx, consisting of membrane-bound proteoglycans and attached glycosaminoglycans plays an important role in vascular homeostasis. We aimed to assess whether glycocalyx mRNA transcripts are differentially expressed in placental tissue of pre-eclamptic and normotensive women. METHODS: We evaluated the expression of transcripts encoding for proteins involved in glycocalyx synthesis and degradation using a microarray analysis of placental mRNA obtained from pre-eclamptic and normotensive women. Participants were recruited from the department of obstetrics at a university hospital in Amsterdam, The Netherlands. The most prominent differentially expressed transcript was validated by qPCR on 112 additional placenta samples. RESULTS: Of 78 preselected genes involved in glycocalyx synthesis and degradation, only HS3ST3A1 mRNA was differentially expressed in placental tissue obtained from pre-eclamptic women (N = 12) compared to normotensive women (N = 12, fold change = 0.61, p = 0.02). Validation with qPCR in additional placental samples of 64 normotensive and 48 pre-eclamptic women confirmed that normalized mRNA expression of HS3ST3A1 was decreased by 27% (95% CI 14%-41%) in placental tissue obtained from pre-eclamptic compared to normotensive women (p < 0.001). HS3ST3A1 expression was positively correlated with neonatal birth weight in normotensive women (r = 0.35, p < 0.01) and inversely correlated with mean arterial pressure of women with pre-eclampsia (r = 0.32, p = 0.02). CONCLUSIONS: The mRNA expression of HS3ST3A1, which encodes for a 3-O sulfating enzyme of heparan sulfate (3-OST-3A1), is decreased in pre-eclamptic placental tissue. Expression of this glycocalyx synthesis transcript is correlated with maternal blood pressure and neonatal birth weight, suggesting a possible role in pre-eclampsia-associated placental dysfunction.

Increased glucocerebrosidase expression and activity in preeclamptic placenta.

INTRODUCTION: Lysosomal glucosidase beta acid (GBA) deficiency is inherent to Gaucher disease, Parkinsonism and Lewy-body dementia. Increased GBA expression has never been associated with human disease. We describe increased GBA expression and activity in placenta from preeclamptic pregnancies. METHODS: 112 placenta biopsies were available for qPCR, analysis of GBA gene expression and activity. Microanalysis was performed on 20 placenta samples. Alternatively spliced placental GBA transcripts were cloned, expressed in HEK293 cells and analyzed by Western blot and activity assay. RESULTS: GBA is expressed in the syncytiotrophoblast layer of human placenta already at 5 weeks of gestation. We identified five novel GBA transcripts in placenta that enzymatically inactive when expressed in HEK293 cells. Both GBA RNA expression and enzymatic activity are upregulated in preeclamptic placenta. Microarray analysis of 20 placenta tissues identified 158 genes co-regulating with GBA expression and gene enrichment analysis highlights lysosomal function. In our micro-array data GBA expression does not correlate with FLT1 expression, currently the most powerful marker for preeclampsia. There are 89 transcripts that are negatively correlated with GBA expression of which BMP4 and TFEB are interesting as they are essential to early placenta function. DISCUSSION: Although very speculative, we hypothesize that increased GBA expression might relate to placentation through decreased BMP4 signaling or vascularization through downregulation of TFEB. Ceramide, the product of hydrolysis of glucosylceramide by GBA and involved in the regulation of cell differentiation, survival and apoptosis, is another putative candidate linking increased GBA activity to preeclampsia. Both pathways merit further investigation.

Seven placental transcripts characterize HELLP-syndrome.

The human placenta is prerequisite for the development of gestational hypertensive diseases like early-onset preeclampsia (PE) and Hemolysis, Elevated Liver enzymes and Low platelets (HELLP) syndrome. Both syndromes are associated with extensive maternal and perinatal mortality, and morbidity with life long consequences. We aimed to investigate differences in gene expression between placental tissue obtained from normotensive pregnant women and women with PE and HELLP syndrome. Firstly, comparison of Serial Analysis of Gene Expression profiles of 28 weeks' control placenta (available after idiopathic premature delivery) to a HELLP/PE placenta matched for gestational age identified 404 differentially expressed transcripts. Secondly, using sqPCR, the expression levels of 37 of these transcripts were analyzed in placentas of 36 pregnant women, 22 with preeclampsia and HELLP syndrome. Thirdly, nearest centroid classification determined the HELLP specific molecular signature consisting of the upregulated expression of genes encoding the vascular endothelial growth factor receptor (FLT1), leptin (LEP), pappalysin 2 (PAPPA2), and WW domain containing transcription regulator 1 (WWTR1) combined with down regulated expression of the genes encoding cadherin-associated protein (CTNNAL), glutathione S-transferase pi (GSTP1) and calgranulin A (S100A8). This set discriminates HELLP placenta from control and PE placenta with a 24% misclassification rate (95% CI 8.3-41.9%), independent from known risk factors like parity and ethnicity. The transcripts involved correspond to diverse molecular pathways, exemplifying the multigenic molecular basis of the disorder. This distinct placental molecular signature suggests that HELLP is not a PE variant but a separate disease entity. Our data may prove fundamental for the further molecular analysis of PE and HELLP syndrome.