Circular RNAs accumulate in aging human placental tissue and in stillbirth, leading to DNA damage and cellular senescence.

Background: Unexplained stillbirth may occur due to premature placental aging, with unexpected deterioration of placental function for gestational age. Circular RNAs (circRNAs) are enzyme-resistant RNA molecules that accumulate in aging tissues. Furthermore, circRNAs bind gDNA directly, forming complexes which can induce DNA breaks and genomic instability.

The first trimester human placenta responds to Zika virus infection inducing an interferon (IFN) and antiviral interferon stimulated gene (ISG) response.

Background: Zika virus (ZIKV) is a positive-strand RNA virus of the Flaviviridae family. Maternal ZIKV infection during pregnancy can spread to the placenta and fetus causing severe neurological defects and infants born with microcephaly. Here, we investigated ZIKV infection and the cellular innate antiviral immune response in first trimester human placental explant cultures and isolated primary villus cytotrophoblasts (CTBs).

Factors influencing RNA yield from placenta tissue.

High yield and integrity of placental RNA are crucial for placental transcriptomics studies. We assessed the effects of time to placental collection post-delivery; tissue storage, amount and method used for extraction; mode of delivery; and tissue type on total RNA yield. The optimal protocol for RNA extraction from placental tissue includes cryofreezing of the sample upon collection and RNA extraction from 50 mg of tissue using TRIzol reagent.

Elevated Maternal Folate Status and Changes in Maternal Prolactin, Placental Lactogen and Placental Growth Hormone Following Folic Acid Food Fortification: Evidence from Two Prospective Pregnancy Cohorts.

Folic acid (FA) food fortification in Australia has resulted in a higher-than-expected intake of FA during pregnancy. High FA intake is associated with increased insulin resistance and gestational diabetes. We aimed to establish whether maternal one-carbon metabolism and hormones that regulate glucose homeostasis change in healthy pregnancies post-FA food fortification.

DraculR: A Web-Based Application for In Silico Haemolysis Detection in High-Throughput microRNA Sequencing Data.

The search for novel microRNA (miRNA) biomarkers in plasma is hampered by haemolysis, the lysis and subsequent release of red blood cell contents, including miRNAs, into surrounding fluid. The biomarker potential of miRNAs comes in part from their multicompartment origin and the long-lived nature of miRNA transcripts in plasma, giving researchers a functional window for tissues that are otherwise difficult or disadvantageous to sample. The inclusion of red-blood-cell-derived miRNA transcripts in downstream analysis introduces a source of error that is difficult to identify posthoc and may lead to spurious results.

Haemolysis Detection in MicroRNA-Seq from Clinical Plasma Samples.

The abundance of cell-free microRNA (miRNA) has been measured in blood plasma and proposed as a source of novel, minimally invasive biomarkers for several diseases. Despite improvements in quantification methods, there is no consensus regarding how haemolysis affects plasma miRNA content. We propose a method for haemolysis detection in miRNA high-throughput sequencing (HTS) data from libraries prepared using human plasma.

Placental Transcription Profiling in 6-23 Weeks' Gestation Reveals Differential Transcript Usage in Early Development.

The human placenta is a rapidly developing transient organ that is key to pregnancy success. Early development of the conceptus occurs in a low oxygen environment before oxygenated maternal blood begins to flow into the placenta at ~10-12 weeks' gestation. This process is likely to substantially affect overall placental gene expression.

Placental Inflammasome mRNA Levels Differ by Mode of Delivery and Fetal Sex.

Parturition signals the end of immune tolerance in pregnancy. Term labour is usually a sterile inflammatory process triggered by damage associated molecular patterns (DAMPs) as a consequence of functional progesterone withdrawal. Activation of DAMPs recruits leukocytes and inflammatory cytokine responses in the myometrium, decidua, cervix and fetal membranes.

Large-scale transcriptome-wide profiling of microRNAs in human placenta and maternal plasma at early to mid gestation.

MicroRNAs (miRNAs) are increasingly seen as important regulators of placental development and opportunistic biomarker targets. Given the difficulty in obtaining samples from early gestation and subsequent paucity of the same, investigation of the role of miRNAs in early gestation human placenta has been limited. To address this, we generated miRNA profiles using 96 placentas from presumed normal pregnancies, across early gestation, in combination with matched profiles from maternal plasma.

Effect of Selenium and Iodine on Oxidative Stress in the First Trimester Human Placenta Explants.

Imbalanced maternal micronutrient status, poor placentation, and oxidative stress are associated with greater risk of pregnancy complications, which impact mother and offspring health. As selenium, iodine, and copper are essential micronutrients with key roles in antioxidant systems, this study investigated their potential protective effects on placenta against oxidative stress. First trimester human placenta explants were treated with different concentrations of selenium (sodium selenite), iodine (potassium iodide), their combination or copper (copper (II) sulfate).

The effect of zinc on human trophoblast proliferation and oxidative stress.

Adequate Zinc (Zn) intake is required to prevent multiple teratogenic effects however deviations from adequate Zn intake, including high maternal Zn status, have been linked to increased incidence of pregnancy complications, including those associated with inadequate placentation. Using placental trophoblast HTR8/SVneo cells and first trimester human placental explants (n = 12), we assessed the effects of varying Zn concentrations on trophoblast proliferation, viability, apoptosis and oxidative stress. Compared to physiologically normal Zn levels (20 µM), HTR-8/SVneo cell proliferation index was significantly lower in the presence of physiologically elevated (40 µM; P = .

Maternal folate, one-carbon metabolism and pregnancy outcomes.

Single nucleotide polymorphisms and pre- and peri-conception folic acid (FA) supplementation and dietary data were used to identify one-carbon metabolic factors associated with pregnancy outcomes in 3196 nulliparous women. In 325 participants, we also measured circulating folate, vitamin B12 and homocysteine. Pregnancy outcomes included preeclampsia (PE), gestational hypertension (GHT), small for gestational age (SGA), spontaneous preterm birth (sPTB) and gestational diabetes mellitus (GDM).

Quality control measures for placental sample purity in DNA methylation array analyses.

The purity of tissue samples can affect the accuracy and utility of DNA methylation array analyses. This is particularly important for the placenta which is globally hypomethylated compared to other tissues. Placental villous tissue from early pregnancy terminations can be difficult to separate from non-villous tissue, resulting in potentially inaccurate results.

Characterization of 5-methylcytosine and 5-hydroxymethylcytosine in human placenta cell types across gestation.

The placenta is an important organ in pregnancy, however, very little is understood about placental development at a molecular level. This includes the role of epigenetic mechanisms and how they change throughout gestation. DNA methylation studies in this organ are complicated by the different cell types that make up the placenta, each with their own unique transcriptome and epigenome.

Isolation of villous cytotrophoblasts from second trimester human placentas.

Human placental functional studies are often performed using immortalised trophoblast cells and cell lines established from human choriocarcinomas, which, while practical, may not truly reflect trophoblast function in vivo. Primary trophoblast cultures derived from human placentas following pregnancy termination or delivery are more clinically relevant, but trophoblast isolation protocols are only available for 1st trimester and term placental tissues. Here we report a method for isolation and purification of primary villous cytotrophoblasts from 2nd trimester human placentas, that yields >99% trophoblast purity as shown by immunofluorescence.