Increasing maternal glucose concentrations is insufficient to restore placental glucose transfer in chorionic somatomammotropin RNA interference pregnancies

We previously demonstrated impaired placental nutrient transfer in chorionic somatomammotropin (CSH) RNA interference (RNAi) pregnancies, with glucose transfer being the most impacted. Thus, we hypothesized that despite experimentally elevating maternal glucose, diminished umbilical glucose uptake would persist in CSH RNAi pregnancies, demonstrating the necessity of CSH for adequate placental glucose transfer. Trophectoderm of sheep blastocysts (9 days of gestational age; dGA) were infected with a lentivirus expressing either nontargeting control (CON RNAi; n = 5) or CSH-specific shRNA (CSH RNAi; n = 7) before transfer into recipient sheep. At 126 dGA, pregnancies were fitted with vascular catheters and underwent steady-state metabolic studies (3H2O transplacental diffusion) at 137 ± 0 dGA, before and during a maternal hyperglycemic clamp. Umbilical glucose and oxygen uptakes, as well as insulin and IGF1 concentrations, were impaired (P ≤ 0.01) in CSH RNAi fetuses and were not rescued by elevated maternal glucose. This is partially due to impaired uterine and umbilical blood flow (P ≤ 0.01). However, uteroplacental oxygen utilization was greater (P ≤ 0.05) during the maternal hyperglycemic clamp, consistent with greater placental oxidation of substrates. The relationship between umbilical glucose uptake and the maternal-fetal glucose gradient was analyzed, and while the slope (CON RNAi, Y = 29.54X +74.15; CSH RNAi, Y = 19.05X + 52.40) was not different, the y-intercepts and elevation were (P = 0.003), indicating reduced maximal glucose transport during maternal hyperglycemia. Together, these data suggested that CSH plays a key role in modulating placental metabolism that ultimately promotes maximal placental glucose transfer.NEW & NOTEWORTHY The current study demonstrated a novel, critical autocrine role for chorionic somatomammotropin in augmenting placental glucose transfer and maintaining placental oxidative metabolism. In pregnancies with CSH deficiency, excess glucose in maternal circulation is insufficient to overcome fetal hypoglycemia due to impaired placental glucose transfer and elevated placental metabolic demands. This suggests that perturbations in glucose transfer in CSH RNAi pregnancies are due to compromised metabolic efficiency along with reduced placental mass.

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. Circulating folate, B12, homocysteine, prolactin (PRL), human placental lactogen (hPL) and placental growth hormone (GH2) were measured in early pregnancy maternal blood in women with uncomplicated pregnancies prior to (SCOPE: N = 604) and post (STOP: N = 711)-FA food fortification. FA food fortification resulted in 63% higher maternal folate. STOP women had lower hPL (33%) and GH2 (43%) after 10 weeks of gestation, but they had higher PRL (29%) and hPL (28%) after 16 weeks. FA supplementation during pregnancy increased maternal folate and reduced homocysteine but only in the SCOPE group, and it was associated with 54% higher PRL in SCOPE but 28% lower PRL in STOP. FA food fortification increased maternal folate status, but supplements no longer had an effect, thereby calling into question their utility. An altered secretion of hormones that regulate glucose homeostasis in pregnancy could place women post-fortification at an increased risk of insulin resistance and gestational diabetes, particularly for older women and those with obesity.

Impact of Placental SLC2A3 Deficiency during the First-Half of Gestation

In the ruminant placenta, glucose uptake and transfer are mediated by facilitative glucose transporters SLC2A1 (GLUT1) and SLC2A3 (GLUT3). SLC2A1 is located on the basolateral trophoblast membrane, whereas SLC2A3 is located solely on the maternal-facing, apical trophoblast membrane. While SLC2A3 is less abundant than SLC2A1, SLC2A3 has a five-fold greater affinity and transport capacity. Based on its location, SLC2A3 likely plays a significant role in the uptake of glucose into the trophoblast. Fetal hypoglycemia is a hallmark of fetal growth restriction (FGR), and as such, any deficiency in SLC2A3 could impact trophoblast glucose uptake and transfer to the fetus, thus potentially setting the stage for FGR. By utilizing in vivo placenta-specific lentiviral-mediated RNA interference (RNAi) in sheep, we were able to significantly diminish (p ≤ 0.05) placental SLC2A3 concentration, and determine the impact at mid-gestation (75 dGA). In response to SLC2A3 RNAi (n = 6), the fetuses were hypoglycemic (p ≤ 0.05), exhibited reduced fetal growth, including reduced fetal pancreas weight (p ≤ 0.05), which was associated with reduced umbilical artery insulin and glucagon concentrations, when compared to the non-targeting sequence (NTS) RNAi controls (n = 6). By contrast, fetal liver weights were not impacted, nor were umbilical artery concentrations of IGF1, possibly resulting from a 70% increase (p ≤ 0.05) in umbilical vein chorionic somatomammotropin (CSH) concentrations. Thus, during the first half of gestation, a deficiency in SLC2A3 results in fetal hypoglycemia, reduced fetal development, and altered metabolic hormone concentrations. These results suggest that SLC2A3 may be the rate-limiting placental glucose transporter during the first-half of gestation in sheep.

Uptake of Phosphate, Calcium, and Vitamin D by the Pregnant Uterus of Sheep in Late Gestation: Regulation by Chorionic Somatomammotropin Hormone

Minerals are required for the establishment and maintenance of pregnancy and regulation of fetal growth in mammals. Lentiviral-mediated RNA interference (RNAi) of chorionic somatomammotropin hormone (CSH) results in both an intrauterine growth restriction (IUGR) and a non-IUGR phenotype in sheep. This study determined the effects of CSH RNAi on the concentration and uptake of calcium, phosphate, and vitamin D, and the expression of candidate mRNAs known to mediate mineral signaling in caruncles (maternal component of placentome) and cotyledons (fetal component of placentome) on gestational day 132. CSH RNAi Non-IUGR pregnancies had a lower umbilical vein−umbilical artery calcium gradient (p < 0.05) and less cotyledonary calcium (p < 0.05) and phosphate (p < 0.05) compared to Control RNAi pregnancies. CSH RNAi IUGR pregnancies had less umbilical calcium uptake (p < 0.05), lower uterine arterial and venous concentrations of 25(OH)D (p < 0.05), and trends for lower umbilical 25(OH)D uptake (p = 0.059) compared to Control RNAi pregnancies. Furthermore, CSH RNAi IUGR pregnancies had decreased umbilical uptake of calcium (p < 0.05), less uterine venous 25(OH)D (vitamin D metabolite; p = 0.055), lower caruncular expression of SLC20A2 (sodium-dependent phosphate transporter; p < 0.05) mRNA, and lower cotyledonary expression of KL (klotho; p < 0.01), FGFR1 (fibroblast growth factor receptor 1; p < 0.05), FGFR2 (p < 0.05), and TRPV6 (transient receptor potential vanilloid member 6; p < 0.05) mRNAs compared to CSH RNAi Non-IUGR pregnancies. This study has provided novel insights into the regulatory role of CSH for calcium, phosphate, and vitamin D utilization in late gestation.

Maternal Hypothyroidism in Rats Reduces Placental Lactogen, Lowers Insulin Levels, and Causes Glucose Intolerance

Hypothyroidism increases the incidence of gestational diabetes mellitus (GDM) but the mechanisms responsible are unknown. This study aimed to assess the pathophysiological mechanisms by which hypothyroidism leads to glucose intolerance in pregnancy. Hypothyroidism was induced in female Sprague-Dawley rats by adding methimazole (MMI) to drinking water at moderate (MOD, MMI at 0.005% w/v) and severe (SEV, MMI at 0.02% w/v) doses from 1 week before pregnancy and throughout gestation. A nonpregnant cohort received the same dose for the same duration but were not mated. On gestational day 16 (GD16), or nonpregnant day 16 (NP16), animals were subjected to an intraperitoneal glucose tolerance test. Tissues and blood samples were collected 4 days later. Hypothyroidism induced a diabetic-like phenotype by GD16 in pregnant females only. Pregnant MOD and SEV females had reduced fasting plasma insulin, less insulin following a glucose load, and altered expression of genes involved in insulin signaling within skeletal muscle and adipose tissue. Hypothyroidism reduced rat placental lactogen concentrations, which was accompanied by reduced percentage β-cell cross-sectional area (CSA) relative to total pancreas CSA, and a reduced number of large β-cell clusters in the SEV hypothyroid group. Plasma triglycerides and free fatty acids were reduced by hypothyroidism in pregnant rats, as was the expression of genes that regulate lipid homeostasis. Hypothyroidism in pregnant rats results in a diabetic-like phenotype that is likely mediated by impaired β-cell expansion in pregnancy. This pregnancy-specific phenomenon is likely due to reduced placental lactogen secretion.

Adiponectin Promotes Maternal β-Cell Expansion Through Placental Lactogen Expression

Hypoadiponectinemia is a risk factor of gestational diabetes mellitus (GDM). Our previous study reported that adiponectin gene knockout mice (Adipoq ^-/- ) develop GDM due to insulin insufficiency. The main objective of this study was to elucidate the underlying mechanism through which adiponectin controls islet expansion during pregnancy. A significant reduction in β-cell proliferation rates, β-cell areas, and blood insulin concentrations was detected in Adipoq ^-/- mice at midpregnancy. Surprisingly, conditionally knocking down adiponectin receptor 1 (AdipoR1) or AdipoR2 genes in β-cells during pregnancy did not reduce β-cell proliferation rates or blood insulin concentrations. In vitro adiponectin treatment also failed to show any effect on β-cell proliferation of isolated pancreatic islets. It was reported that placental lactogen (PL) plays a crucial role in pregnancy-induced maternal β-cell proliferation. A significant decrease in phosphorylation of signal transducer and activator of transcription 5, a downstream molecule of PL signaling, was observed in islets from Adipoq ^-/- dams. The mRNA levels of mouse PL genes were robustly decreased in the placentas of Adipoq ^-/- dams. In contrast, adiponectin treatment increased PL expression in human placenta explants and JEG3 trophoblast cells. Most importantly, bovine PL injection restored β-cell proliferation and blood insulin concentrations in Adipoq ^-/- dams. Together, these results demonstrate that adiponectin plays a vital role in pregnancy-induced β-cell proliferation by promoting PL expression in trophoblast cells.

Chorionic somatomammotropin RNA interference alters fetal liver glucose utilization

Chorionic somatomammotropin (CSH) is a placenta-specific hormone associated with fetal growth, and fetal and maternal metabolism in both humans and sheep. We hypothesized that CSH deficiency could impact sheep fetal liver glucose utilization. To generate CSH-deficient pregnancies, day 9 hatched blastocysts were infected with lentiviral particles expressing CSH-specific shRNA (RNAi) or scramble control shRNA (SC) and transferred to synchronized recipients. CSH RNAi generated two distinct phenotypes at 135 days of gestational age (dGA); pregnancies with IUGR (RNAi-IUGR) or with normal fetal weight (RNAi-NW). Fetal body, fetal liver and placental weights were reduced (P < 0.05) only in RNAi-IUGR pregnancies compared to SC. Umbilical artery plasma insulin and insulin-like growth factor 1 (IGF1) concentrations were decreased, whereas insulin receptor beta (INSR) concentration in fetal liver was increased (P < 0.05) in both RNAi phenotypes. The mRNA concentrations of IGF1, IGF2, IGF binding protein 2 (IGFBP2) and IGFBP3 were decreased (P < 0.05) in fetal livers from both RNAi phenotypes. Fetal liver glycogen concentration and glycogen synthase 1 (GYS1) concentration were increased (P < 0.05), whereas fetal liver phosphorylated-GYS (inactive GYS) concentration was reduced (P < 0.05) in both RNAi phenotypes. Lactate dehydrogenase B (LDHB) concentration was increased (P < 0.05) and IGF2 concentration was decreased (P < 0.05) in RNAi-IUGR fetal livers only. Our findings suggest that fetal liver glucose utilization is impacted by CSH RNAi, independent of IUGR, and is likely tied to enhanced fetal liver insulin sensitivity in both RNAi phenotypes. Determining the physiological ramifications of both phenotypes, may help to differentiate direct effect of CSH deficiency or its indirect effect through IUGR.

Prolactin receptor-mediated activation of pSTAT5 in the pregnant mouse brain

Pregnancy represents a period of remarkable adaptive physiology throughout the body, with many of these important adaptations mediated by changes in gene transcription in the brain. A marked activation of the transcription factor signal transducer and activator of transcription 5 (STAT5) has been described in the brain during pregnancy and likely drives some of these changes. We aimed to investigate the physiological mechanism causing this increase in phosphorylated STAT5 (pSTAT5) during pregnancy. In various tissues, STAT5 is known to be activated by a number of different cytokines, including erythropoietin, growth hormone and prolactin. Because the lactogenic hormones that act through the prolactin receptor (PRLR), prolactin and its closely-related placental analogue placental lactogen, are significantly increased during pregnancy, we hypothesised that this receptor was primarily responsible for the pregnancy-induced increase in pSTAT5 in the brain. By examining temporal changes in plasma prolactin levels and the pattern of pSTAT5 immunoreactivity in the hypothalamus during early pregnancy, we found that the level of pSTAT5 was sensitive to circulating levels of endogenous prolactin. Using a transgenic model to conditionally delete PRLRs from forebrain neurones (Prlr^lox/lox /CamK-Cre), we assessed the relative contribution of the PRLR to the up-regulation of pSTAT5 in the brain of pregnant mice. In the absence of PRLRs on most forebrain neurones, a significant reduction in pSTAT5 was observed throughout the hypothalamus and amygdala in late pregnancy, confirming that PRLR is key in mediating this response. The exception to this was the hypothalamic paraventricular nucleus, where only 17% of pSTAT5 immunoreactivity during pregnancy was in PRLR-expressing cells. Taken together, these data indicate that, although there are region-specific mechanisms involved, lactogenic activity through the PRLR is the primary signal activating STAT5 in the brain during pregnancy.

Igf2 deletion alters mouse placenta endocrine capacity in a sexually dimorphic manner

The placenta regulates materno-fetal nutrient transfer and secretes hormones that enable maternal physiological support of the pregnancy. In mice, these functions are performed by the labyrinth (Lz) and junctional (Jz) zones, respectively. Insulin-like growth factor 2 (Igf2) is an imprinted gene expressed by the conceptus that is important for promoting fetal growth and placenta formation. However, the specific role of Igf2 in the Jz in regulating placental endocrine function and fetal development is unknown. This study used a novel model to investigate the effect of conditional loss of Igf2 in the Jz (Jz-Igf2UE) on placental endocrine cell formation and the expression of hormones and IGF signaling components in placentas from female and male fetuses. Jz-Igf2UE altered gross placental structure and expression of key endocrine and signaling genes in a sexually dimorphic manner. The volumes of spongiotrophoblast and glycogen trophoblast in the Jz were decreased in placentas from female but not male fetuses. Expression of insulin receptor was increased and expression the MAPK pathway genes (Mek1, P38α) decreased in the placental Jz of female but not male fetuses. In contrast, expression of the type-1 and -2 IGF receptors and the MAPK pathway genes (H-ras, N-ras, K-ras) was decreased in the placental Jz from male but not female fetuses. Expression of the steroidogenic gene, Cyp17a1, was increased and placental lactogen-2 was decreased in the placenta of both sexes. In summary, we report that Jz-Igf2UE alters the cellular composition, IGF signaling components and hormone expression of the placental Jz in a manner largely dependent on fetal sex.

Determinants of Maternal Insulin Resistance during Pregnancy: An Updated Overview

Insulin resistance changes over time during pregnancy, and in the last half of the pregnancy, insulin resistance increases considerably and can become severe, especially in women with gestational diabetes and type 2 diabetes. Numerous factors such as placental hormones, obesity, inactivity, an unhealthy diet, and genetic and epigenetic contributions influence insulin resistance in pregnancy, but the causal mechanisms are complex and still not completely elucidated. In this review, we strive to give an overview of the many components that have been ascribed to contribute to the insulin resistance in pregnancy. Knowledge about the causes and consequences of insulin resistance is of extreme importance in order to establish the best possible treatment during pregnancy as severe insulin resistance can result in metabolic dysfunction in both mother and offspring on a short as well as long-term basis.

Chromosomal architecture and placental expression of the human growth hormone gene family are targeted by pre-pregnancy maternal obesity

The human (h) placental lactogenic hormone chorionic somatomammotropin (CS) is highly produced during pregnancy and acts as a metabolic adaptor in response to maternal insulin resistance. Maternal obesity can exacerbate this "resistance", and a >75% decrease in CS RNA levels was observed in term placentas from obese vs. lean women. The genes coding for hCS ( hCS-A and hCS-B) and placental growth hormone ( hGH-V) as well as the hCS-L pseudogene and pituitary growth hormone (GH) gene ( hGH-N) are located at a single locus on chromosome 17. Three remote hypersensitive sites (HS III-V) located >28 kb upstream of hGH-N as well as local hCS gene promoter and enhancer regions are implicated in hCS gene expression. A placenta-specific chromosomal architecture, including interaction between HS III-V and hCS but not hGH gene promoters, was detected in placentas from lean women (BMI <25 kg/m²) by using the chromosome conformation capture assay. This architecture was disrupted by pre-pregnancy maternal obesity (BMI >35 kg/m²), resulting in a predominant interaction between HS III and the hGH-N promoter, which was also observed in nonplacental tissues. This was accompanied by a decrease in hCS levels, which was consistent with reduced RNA polymerase II and CCAAT/enhancer-binding protein-β association with individual hCS promoter and enhancer sequences, respectively. Thus, pre-pregnancy maternal obesity disrupts the placental hGH/CS gene locus chromosomal architecture. However, based on data from obese women who develop GDM, insulin treatment partially recapitulates the chromosomal architecture seen in lean women and positively affects hCS production, presumably facilitating prolactin receptor-related signaling by hCS.

Somatolactogens and diabetic retinopathy

IMPORTANCE

Diabetic retinopathy (DR) is one of the most common of all diabetic complications. The number of people with DR in the United States is expected to increase to 16 million by 2050. DR is the leading cause of blindness among working-age adults in many different countries, including the United States. In later DR stages, neovascularization is associated with extensive retinal capillary non-perfusion and vitreo-proliferation leading to retinal detachment. This neovascularization is orchestrated by an imbalance of growth factors in the retina from which somatolactogens (pituitary growth hormone, GH-N; placental growth hormone, GH-V; prolactin, PRL; and placental lactogen, PL, also referred as chorionic somatomammotropin, CSH), may play an important role.

OBSERVATIONS

Somatolactogens are a group of hormones that share many structural and functional features. They are important for physiological changes in pregnancy, for adequate development of the fetus, and in the case of GH-N, for promoting growth after birth. GH-N is synthesized by the anterior pituitary, GH-V and PL are secreted by the placenta, whereas, PRL is synthesized by the anterior pituitary and uterine decidua. However, in recent years the expression of GH-N and PRL and their receptors have been detected in other tissues including the retina, acting as neuroprotective and pro-angiogenic agents. The relationship of GH-N and diabetic retinopathy (DR) was established many years ago when it was observed that its deficiency was related to regression of DR while an increase in serum levels of GH-N, GH-V, and PL promoted DR. While more studies are needed to define the potential implications of GH-V and PL in DR pathogenesis, it has been demonstrated that GH-N and PRL participate in DR by enhancing neovascularization. Some PRL isoforms, however, have shown an anti-angiogenic activity rather than pro-angiogenesis and appears to be PRL's main role in the regulation of retinal vasculature.

CONCLUSIONS

Somatolactogens are a group of hormones with a significant role in neuroprotection and angiogenesis regulation in the eye. Understanding the mechanisms of angiogenesis regulation by somatolactogens will potentially lead to the development of new drugs for DR.

Screening for fetal growth restriction using fetal biometry combined with maternal biomarkers

Fetal growth restriction is a major determinant of perinatal morbidity and mortality. Screening for fetal growth restriction is a key element of prenatal care but it is recognized to be problematic. Screening using clinical risk assessment and targeting ultrasound to high-risk women is the standard of care in the United States and United Kingdom, but the approach is known to have low sensitivity. Systematic reviews of randomized controlled trials do not demonstrate any benefit from universal ultrasound screening for fetal growth restriction in the third trimester, but the evidence base is not strong. Implementation of universal ultrasound screening in low-risk women in France failed to reduce the risk of complications among small-for-gestational-age infants but did appear to cause iatrogenic harm to false positives. One strategy to making progress is to improve screening by developing more sensitive and specific tests with the key goal of differentiating between healthy small fetuses and those that are small through fetal growth restriction. As abnormal placentation is thought to be the major cause of fetal growth restriction, one approach is to combine fetal biometry with an indicator of placental dysfunction. In the past, these indicators were generally ultrasonic measurements, such as Doppler flow velocimetry of the uteroplacental circulation. However, another promising approach is to combine ultrasonic suspicion of small-for-gestational-age infant with a blood test indicating placental dysfunction. Thus far, much of the research on maternal serum biomarkers for fetal growth restriction has involved the secondary analysis of tests performed for other indications, such as fetal aneuploidies. An exemplar of this is pregnancy-associated plasma protein A. This blood test is performed primarily to assess the risk of Down syndrome, but women with low first-trimester levels are now serially scanned in later pregnancy due to associations with placental causes of stillbirth, including fetal growth restriction. The development of "omic" technologies presents a huge opportunity to identify novel biomarkers for fetal growth restriction. The hope is that when such markers are measured alongside ultrasonic fetal biometry, the combination would have strong predictive power for fetal growth restriction and its related complications. However, a series of important methodological considerations in assessing the diagnostic effectiveness of new tests will have to be addressed. The challenge thereafter will be to identify novel disease-modifying interventions, which are the essential partner to an effective screening test to achieve clinically effective population-based screening.

FGF-2b and h-PL Transform Duct and Non-Endocrine Human Pancreatic Cells into Endocrine Insulin Secreting Cells by Modulating Differentiating Genes

Background: Diabetes mellitus (DM) is a multifactorial disease orphan of a cure. Regenerative medicine has been proposed as novel strategy for DM therapy. Human fibroblast growth factor (FGF)-2b controls β-cell clusters via autocrine action, and human placental lactogen (hPL)-A increases functional β-cells. We hypothesized whether FGF-2b/hPL-A treatment induces β-cell differentiation from ductal/non-endocrine precursor(s) by modulating specific genes expression. Methods: Human pancreatic ductal-cells (PANC-1) and non-endocrine pancreatic cells were treated with FGF-2b plus hPL-A at 500 ng/mL. Cytofluorimetry and Immunofluorescence have been performed to detect expression of endocrine, ductal and acinar markers. Bromodeoxyuridine incorporation and annexin-V quantified cells proliferation and apoptosis. Insulin secretion was assessed by RIA kit, and electron microscopy analyzed islet-like clusters. Results: Increase in PANC-1 duct cells de-differentiation into islet-like aggregates was observed after FGF-2b/hPL-A treatment showing ultrastructure typical of islets-aggregates. These clusters, after stimulation with FGF-2b/hPL-A, had significant (p < 0.05) increase in insulin, C-peptide, pancreatic and duodenal homeobox 1 (PDX-1), Nkx2.2, Nkx6.1, somatostatin, glucagon, and glucose transporter 2 (Glut-2), compared with control cells. Markers of PANC-1 (Cytokeratin-19, MUC-1, CA19-9) were decreased (p < 0.05). These aggregates after treatment with FGF-2b/hPL-A significantly reduced levels of apoptosis. Conclusions: FGF-2b and hPL-A are promising candidates for regenerative therapy in DM by inducing de-differentiation of stem cells modulating pivotal endocrine genes.

Maternal prenatal depression is associated with decreased placental expression of the imprinted gene PEG3

BACKGROUND

Maternal prenatal stress during pregnancy is associated with fetal growth restriction and adverse neurodevelopmental outcomes, which may be mediated by impaired placental function. Imprinted genes control fetal growth, placental development, adult behaviour (including maternal behaviour) and placental lactogen production. This study examined whether maternal prenatal depression was associated with aberrant placental expression of the imprinted genes paternally expressed gene 3 (PEG3), paternally expressed gene 10 (PEG10), pleckstrin homology-like domain family a member 2 (PHLDA2) and cyclin-dependent kinase inhibitor 1C (CDKN1C), and resulting impaired placental human placental lactogen (hPL) expression.

METHOD

A diagnosis of depression during pregnancy was recorded from Manchester cohort participants' medical notes (n = 75). Queen Charlotte's (n = 40) and My Baby and Me study (MBAM) (n = 81) cohort participants completed the Edinburgh Postnatal Depression Scale self-rating psychometric questionnaire. Villous trophoblast tissue samples were analysed for gene expression.

RESULTS

In a pilot study, diagnosed depression during pregnancy was associated with a significant reduction in placental PEG3 expression (41%, p = 0.02). In two further independent cohorts, the Queen Charlotte's and MBAM cohorts, placental PEG3 expression was also inversely associated with maternal depression scores, an association that was significant in male but not female placentas. Finally, hPL expression was significantly decreased in women with clinically diagnosed depression (44%, p < 0.05) and in those with high depression scores (31% and 21%, respectively).

CONCLUSIONS

This study provides the first evidence that maternal prenatal depression is associated with changes in the placental expression of PEG3, co-incident with decreased expression of hPL. This aberrant placental gene expression could provide a possible mechanistic explanation for the co-occurrence of maternal depression, fetal growth restriction, impaired maternal behaviour and poorer offspring outcomes.

β-Cell adaptation in pregnancy

Pregnancy in placental mammals places unique demands on the insulin-producing β-cells in the pancreatic islets of Langerhans. The pancreas anticipates the increase in insulin resistance that occurs late in pregnancy by increasing β-cell numbers and function earlier in pregnancy. In rodents, this β-cell expansion depends on secreted placental lactogens that signal through the prolactin receptor. Then at the end of pregnancy, the β-cell population contracts back to its pre-pregnancy size. In the current review, we focus on how glucose metabolism changes during pregnancy, how β-cells anticipate these changes through their response to lactogens and what molecular mechanisms guide the adaptive compensation. In addition, we summarize current knowledge of β-cell adaptation during human pregnancy and what happens when adaptation fails and gestational diabetes ensues. A better understanding of human β-cell adaptation to pregnancy would benefit efforts to predict, prevent and treat gestational diabetes.

ETS1 induces human trophoblast differentiation

A possible role for the transcription factor v-ets avian erythroblastosis virus E26 oncogene homolog 1 (ETS1) in human trophoblast cell differentiation was examined using a highly enriched fraction of human mononuclear cytotrophoblast cells (CTBs) that differentiate spontaneously in vitro to a multinucleated syncytiotrophoblast cell (STB) phenotype. ETS1 mRNA and protein levels were abundant in freshly isolated CTBs and decreased as the cells differentiated. Silencing of ETS1 expression in freshly prepared CTBs markedly attenuated syncytialization, as demonstrated by desmoplakin staining, and blocked the induction of syncytin, the transcription factor activator protein-2α, placental lactogen, and other STB-specific genes. Conversely, overexpression of ETS1 in primary trophoblast cells induced STB marker gene mRNAs and transactivated each of the gene proximal promoters. Taken together, these findings strongly suggest a critical role for ETS1 in the induction of human villus CTB differentiation. The effect of ETS1 on syncytialization likely results, at least in part, from inhibition of syncytin expression, whereas the induction of STB marker genes likely results in part from transactivation by activator protein-2α.

Hectd1 is required for development of the junctional zone of the placenta

The placenta plays a critical role in the growth and survival of the fetus. Here we demonstrate that the Homologous to the E6-AP Carboxyl Terminus (HECT) domain E3 ubiquitin ligase, Hectd1, is essential for development of the mouse placenta. Hectd1 is widely expressed during placentation with enrichment in trophoblast giant cells (TGCs) and other trophoblast-derived cell subtypes in the junctional and labyrinth zones of the placenta. Disruption of Hectd1 results in mid-gestation lethality and intrauterine growth restriction (IUGR). Variable defects in the gross structure of the mutant placenta are found including alterations in diameter, thickness and lamination. The number and nuclear size of TGCs is reduced. Examination of subtype specific markers reveals altered TGC development with decreased expression of Placental lactogen-1 and -2 (Pl1 and Pl2) and increased expression of Proliferin (Plf). Reduced numbers of spongiotrophoblasts and glycogen trophoblasts were also found at the junctional zone of the Hectd1 mutant placenta. Finally, there was an increase in immature uterine natural killer (uNK) cells in the maternal decidua of the Hectd1 mutant placenta. Proliferation and apoptosis are differentially altered in the layers of the placenta with an increase in both apoptosis and proliferation in the maternal decidua, a decrease in proliferation and increase in apoptosis in the labyrinth layer and both unchanged in the junctional zone. Together these data demonstrate that Hectd1 is required for development of multiple cell types within the junctional zone of the placenta.

Differential placental expression profile of human Growth Hormone/Chorionic Somatomammotropin genes in pregnancies with pre-eclampsia and gestational diabetes mellitus

The human GH/CSH cluster consisting of one pituitary-expressed (GH1) and four placenta-expressed loci has been implicated in maternal metabolic adaptation to pregnancy, regulation of intrauterine and postnatal growth. We investigated how the mRNA expression profile of placental GH2, CSH1 and CSH2 genes and their alternative transcripts correlates with maternal pre-eclampsia (PE) and/or gestational diabetes mellitus (GD). The expression of studied genes in PE placentas (n=17) compared to controls (n=17) exhibited a trend for reduced transcript levels. The alternative transcripts retaining intron 4, GH2-2 and CSH1-2 showed significantly reduced expression in PE cases without growth restriction (P=0.007, P=0.008, respectively). In maternal GD (n=23), a tendency of differential expression was detected only for the GH2 gene and in pregnancies with large-for-gestational-age newborns. Our results, together with those reported by others, are consistent with a pleiotropic effect of placental hGH/CSH genes at the maternal-fetal interface relating to the regulation of fetal growth and the risk of affected maternal metabolism.

Tumor expression of human growth hormone and human prolactin predict a worse survival outcome in patients with mammary or endometrial carcinoma

CONTEXT

Evidence suggests that human GH (hGH) and human prolactin (hPRL) possess an autocrine or paracrine oncogenic role in mammary and endometrial carcinoma. However, especially for hGH, the prognostic relevance of tumor expression of these hormones is not well defined.

OBJECTIVE

We investigated the potential association of tumor mRNA and protein expression of hGH and hPRL with the clinicopathological features of mammary and endometrial carcinoma. The prognostic relevance of the individual or combined expression of hGH and hPRL in mammary and endometrial carcinoma was also determined.

DESIGN

The expression of hGH and hPRL was analyzed in histopathological samples of mammary and endometrial carcinoma, and the respective normal tissues, by in situ hybridization and immunohistochemistry. Kaplan-Meier and Cox regression analysis was performed to examine the association of tumor hGH and hPRL expression with relapse-free survival and overall survival of patients.

RESULTS

hGH expression was significantly associated with lymph node metastasis, tumor stage, human epidermal growth factor receptor-2 status, and proliferative index in mammary carcinoma and with International Federation of Gynecology and Obstetrics grade, myometrial invasion, and ovarian metastases in endometrial carcinoma. hPRL expression was associated with lymph node metastasis, tumor grade, and tumor stage in mammary carcinoma and with International Federation of Gynecology and Obstetrics stage and myometrial invasion in endometrial carcinoma. Both hGH and hPRL expression, individually and combined, are associated with worse relapse-free survival and overall survival in patients with mammary or endometrial carcinoma.

CONCLUSION

Tumor expression of both hGH or hPRL in mammary or endometrial carcinoma is associated with a large and significant difference in survival outcome for patients with these tumors.

Human placental lactogen (hPL-A) activates signaling pathways linked to cell survival and improves insulin secretion in human pancreatic islets

The search for factors either promoting islets proliferation or survival during adult life is a major issue for both type 1 and 2 diabetes mellitus. Among factors with mitogenic activity on pancreatic β-cells, human placental lactogen (hPL) showed stronger activity when compared to the other lactogen hormones: growth hormone (GH) and prolactin (PRL). The aim of the present work is to elucidate the biological and molecular events of hPL isoform A (hPL-A) activity on human cultured islets. We used pure human pancreatic islets and insulinoma cell lines (βTC-1 and RIN, murine and rat respectively) stimulated with hPL-A recombinant protein and we compared hPL-A activity with that of hGH. We showed that hPL-A inhibits apoptosis, both in insulinoma and human islets, by the phosphorylation of AKT protein. Indeed, the antiapoptotic role of hPL-A was mediated by PI3K, p38 and it was independent by PKA, Erk1/2. Compared with hGH, hPL-A modulated at different intervals and/or intensity by the phosphorylation of JAKs/STATs and MAPKinases. Moreover, hPL-A induced PDX-1 intracellular expression, improving beta cell activity and ameliorating insulin secretion in response to high glucose stimulation. Our data support the idea that hPL-A is involved in the regulation of beta cells activity. Importantly, we found that hPL-A can preserve and improve the ability of purified human pancreatic islets cultured to secrete insulin in vitro.

Prolactin and lactation as modifiers of diabetes risk in gestational diabetes

Pregnancy and puerperium are periods of intense hormonal changes. Maternal metabolism adapts to spare the mother from harm on behalf of her developing offspring and major alterations maintain normal glucose tolerance. Insulin secretion increases during a normal pregnancy to compensate for pregnancy-induced insulin resistance and maintain euglycemia. Women at risk for gestational diabetes have insulin resistance before conception. Gestational diabetes develops when a woman at risk is unable to meet the insulin secretory demands imposed by the additional insulin resistance characteristic of pregnancy. The lactogens, human placental lactogen and prolactin, are major stimuli for the adaptation of the endocrine pancreas during gestation. This review discusses the role of lactogens on glucose homeostasis during pregnancy and proposes a mechanism by which the hormonal control of lactation, led by prolactin, may regulate adipocyte biology, glucose and lipid metabolism, and guard postpartum women against type 2 diabetes.

Perfluorooctanoic acid-induced inhibition of placental prolactin-family hormone and fetal growth retardation in mice

Perfluorooctanoic acid (PFOA) is a persistent pollutant worldwide and even found in human cord blood and breast milk. Some animal studies have reported that PFOA causes developmental toxicity such as fetal weight loss, but the mechanism is still unclear. This study focused on developmental toxicity of PFOA, particularly impacts of PFOA on placental endocrine function such as placental prolactin (PRL)-family hormone gene expression and fetal growth in mouse. Time-mated CD-1 mice were dosed by gavage with 0, 2, 10 and 25 mg/kg B.W/day of PFOA (n-10) dissolved with de-ionized water from gestational day (GD) 11-16. During treatment, body weight of each pregnant mouse was measured daily. On day 16, caesarean sections were performed and developmental data were observed. Three placentas from three different pregnant mice were assigned to each of the following experiments. The mRNA levels of mouse placental lactogen (mPL)-II, prolactin like protein (mPLP)-E, -F and Pit-1α and β isotype mRNAs, a transacting factor of mPLs and mPLPs genes, were analyzed using northern blot, in situ hybridization and RT-PCR, respectively. Maternal body weight gain was significantly declined from GD 13 in the PFOA treated groups compared to control. Developmental data such as fetal and placental weights were significantly decreased in accordance with PFOA dosage. Number of dead fetuses and post-implantation losses were significantly increased in the PFOA-exposed groups. In addition, placental efficiency (fetal weight/placental weight) was significantly reduced in PFOA treated groups in accordance with PFOA dosage. Histopathologic changes were observed in placenta. Dose dependent necrotic changes were observed in both 10 mg and 25 mg PFOA treated groups. Cell frequency of glycogen trophoblast cell and parietal trophoblast giant cell were decreased dose dependently in the junctional zone. In the labyrinth zone, sinusoidal trophoblast giant cell frequency was decreased in the 25 mg PFOA treated group. Also, morphological change such as crushed nuclear (atrophy) of trophoblast cells was observed in 25 mg PFOA treated group. Finally, mRNA levels of the mPL-II, mPLP-E, -F and Pit-1α and β were significantly reduced in the PFOA treated groups dose dependently. In addition, the changing pattern between mPL-II, mPLP-E, -F mRNA levels and fetal body weight showed positive relationship. In conclusion, the inhibitory effects of PFOA on the placental prolactin-family hormone genes expression may be secondary effects to insufficient trophoblast cell type differentiation and/or increased trophoblast cell necrosis. The impacts of PFOA on placental development and endocrine function reduced the placental efficiency and partly contributed to the fetal growth retardation in the mouse.

Angiotensin II and angiotensin-(1-7) decrease sFlt1 release in normal but not preeclamptic chorionic villi: an in vitro study

BACKGROUND

During preeclampsia, placental angiogenesis is impaired. Factors released from the placenta including vascular endothelial growth factor (VEGF), placental growth factor (PLGF), soluble VEGF receptor 1 (sFlt1), and soluble endoglin (sEng) are regulatory molecules of placental development and function. While the renin angiotensin system has been shown to regulate angiogenic factors in other research fields, these mechanisms have not been extensively studied during pregnancy.

METHODS

We evaluated the effects of angiotensin II (Ang II) and angiotensin-(1-7) [Ang-(1-7)] on the release of VEGF, PLGF, sFlt1, and sEng from placental chorionic villi (CV). CV were collected from nulliparous third-trimester normotensive and preeclamptic subjects. CV were incubated for 0, 2, 4, and 16 hours with or without Ang II (1 nM and 1 microM) or Ang-(1-7) (1 nM and 1 microM). The release of VEGF, PLGF, sFlt1, sEng, lactate dehydrogenase (LDH), and human placenta lactogen (HPL) was measured by ELISA.

RESULTS

The release of sFlt1, PLGF, sEng from normal and preeclamptic CV increased over time. Release of sFlt1 and sEng was significantly higher from preeclamptic CV. VEGF was below the detectable level of the assay in normal and preeclamptic CV. After 2 hours, sFlt1 release from normal CV was significantly inhibited with Ang II (1 nM and 1 microM) and Ang-(1-7) (1 nM and 1 microM). There was a time-dependent increase in HPL indicating that the CV were functioning normally.

CONCLUSIONS

Our study demonstrates a critical inhibitory role of angiotensin peptides on sFlt1 in normal pregnancy. Loss of this regulation in preeclampsia may allow sFlt1 to increase resulting in anti-angiogenesis and end organ damage in the mother.

Insulin-like Growth Factors-I and -II and Insulin-like Growth Factor Binding Protein-1 during normal pregnancy: pattern of secretion and correlation with other placental hormones

OBJECTIVES

To describe pattern of secretion of insulin-like growth factor (IGF)-I, IGF-II, IGF binding protein (IGFBP)-1 and their correlation with each other and major placental hormones during normal pregnancy.

DESIGN

Longitudinal study.

SETTING

Academic Institutions and a Tertiary Care Maternity Hospital.

PARTICIPANTS

Healthy women with singleton uncomplicated pregnancies (N = 35).

MEASUREMENTS

Serum levels of IGF-I, IGF-II, IGFBP-1, chorionic gonadotrophin (HCG), placental lactogen (HPL), prolactin, oestradiol and progesterone were studied thrice during the antenatal period and within 24 h of delivery.

RESULTS

IGF-I, IGFBP-1, HPL, prolactin, oestradiol and progesterone increased and HCG decreased significantly with advancing gestation (Repeated measures ANOVA: P < 0.01 to 0.0001). IGF-II levels were not significantly affected by period of gestation. Significant negative correlations (multiple regression analysis) were seen between IGFBP-1 and prolactin at 28 +/- 2 (P = 0.0226) and 36 +/- 2 (P = 0.0417) weeks of amenorrhoea (WOA) and between oestradiol and IGF-II at 36 +/- 2 WOA (P = 0.037). Prolactin and IGF-I at 14 +/- 2 WOA (P = 0.0225) and progesterone and IGFBP-1 at 28 +/- 2 WOA (P = 0.0216) correlated positively.

CONCLUSIONS

Maternal IGF-I and IGFBP-1 but not IGF-II significantly increase as pregnancy advances. Components of the IGF system regulate or are affected by some of the placental hormones and the effects vary with the period of gestation.

[Clinicopathologic analysis of uterine epithelioid trophoblastic tumor]

OBJECTIVE

To study the clinicopathologic features, immunophenotype, differential diagnosis and prognosis of uterine epithelioid trophoblastic tumor(ETT).

METHODS

From 2000 to 2007, 5 ETTs cases were diagnosed in the affiliated Women's Hospital, School of Medicine, Zhejiang University. The pathologic characteristics and immunophenotype of the tumors were analyzed by histological examination and immunohistochemistry of CK18, p63, inhibin-alpha, HCG, HPL, PLAP and Ki-67. The clinical prognostic factors were evaluated based on a following-up data with a period of 11 - 50 months.

RESULTS

The overall prevalence of ETT was 0.48% among all the gestational trophoblastic diseases patients received in the same period. Five ETT patients were in the reproductive ages with a median of 33 years. Histologically, the tumor showed an invasive, nodular growth consisting of uniform mononuclear trophoblastic cells. There were zones of hyaline material in the tumour nests. Necrosis was commonly seen with a characteristic geographic pattern. Immunohistochemically, all cases displayed a diffuse CK18 and p63 positivity, to be either positive focally or negative for HCG, HPL and PLAP staining. Inhibin-alpha staining was positive or negative either in the 5 cases. Two patients died of the tumour relapse: one died after 1 year with the tumor having a high mitotic activity (averagely 15 mitotic figures per 10 high-power fields), and the other died of lung metastasis 2 years after the diagnosis.

CONCLUSIONS

ETT is a rare trophoblastic disease with distinct clinicopathological features and immunostaining patterns. A high mitotic index and lung metastasis are indicators for an unfavorable prognosis.

Effects of cadmium on the expression of placental lactogens and Pit-1 genes in the rat placental trophoblast cells

Cadmium is an endocrine disrupter (ED) with detrimental effects on mammalian reproduction. The placenta is a primary target for cadmium toxicity during pregnancy. Very little of this metal crosses the placenta to the fetus, and consequently it accumulates in high concentrations in the placenta. Cadmium affects on steroid synthesis and has estrogen- and androgen-like activities. In this study, we investigated the toxic effects of cadmium on placental trophoblast cells as well as the mRNA levels of placental lactogens (PLs), which are under the control of estrogen and play a pivotal role during pregnancy. Pregnant F344 Fisher rats were injected subcutaneously with 0, 0.2, and 2.0mg/kg BW/day of cadmium (CdCl(2)) dissolved in saline from days 11 to 19 of pregnancy and were sacrificed on day 20. The mRNA levels of the PL-Iv and -II genes and Pit-1alpha and beta isotype genes, the trans-acting factor of PLs, were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction, respectively. The frequency of the placental trophoblast cells was observed histochemically. Developmental data and apoptotic chromosomal DNA fragmentation of placental cells were also observed. The mRNA levels of PL-Iv and -II were reduced in a dose-dependent manner by cadmium. The mRNA levels of the Pit-1alpha and beta isotype genes were also reduced by cadmium. In the uterus-conjugated region of the placental junctional zone, the frequency rates of trophoblast cells were lower in the cadmium-treated groups than in the control group. High-dose cadmium exposure (2.0mg) induced not only the reduction of trophoblast cell frequency but also apoptotic chromosomal DNA fragmentation in the junctional zone of the placenta. Developmental metrics such as placental and fetal weights and a number of live fetuses, decreased, while a numbers of resorptions, dead fetuses, and post-implantation losses increased significantly (p<0.05) in the cadmium-treated groups compared to the control. These data suggested that cadmium inhibits the expression of PL genes and reduces the number of trophoblast cells in the rat placenta via an estrogen-like activity, leading to significant toxic effects on placental growth and physiological function in rats.

Effects of prenatal tobacco exposure on gene expression profiling in umbilical cord tissue

Maternal smoking doubles the risk of delivering a low birth weight infant. The purpose of this study was to analyze differential gene expression in umbilical cord tissue as a function of maternal smoking, with an emphasis on growth-related genes. We recruited 15 pregnant smokers and 15 women who never smoked during pregnancy to participate. RNA was isolated from umbilical cord tissue collected and snap frozen at the time of delivery. Microarray analysis was performed using the Affymetrix GeneChip Scanner 3000. Six hundred seventy-eight probes corresponding to 545 genes were differentially expressed (i.e. had an intensity ratio > +/- 1.3 and a corrected significance value p < 0.005) in tissue obtained from smokers versus nonsmokers. Genes important for fetal growth, angiogenesis, or development of connective tissue matrix were upregulated among smokers. The most highly upregulated gene was CSH1, a somatomammotropin gene. Two other somatomammotropin genes (CSH2 and CSH-L1) were also upregulated. The most highly downregulated gene was APOBEC3A; other downregulated genes included those that may be important in immune and barrier protection. Validation of the three somatomammotropin genes showed a high correlation between qPCR and microarray expression. We conclude that maternal smoking may be associated with altered gene expression in the offspring.

Induction of central leptin resistance in hyperphagic pseudopregnant rats by chronic prolactin infusion

Pregnancy in rats is associated with hyperphagia, increased fat deposition, and elevated plasma leptin concentrations. Elevated leptin would be expected to inhibit food intake, but hypothalamic leptin resistance develops around midpregnancy, allowing hyperphagia to be maintained and excess energy to be stored as fat in preparation for future metabolic demands of lactation. To investigate the hormonal mechanisms inducing leptin resistance during pregnancy, the anorectic response to leptin was examined during pseudopregnancy. Pseudopregnant rats have identical hormonal profiles to early pregnancy, but no placenta formation, allowing differentiation of maternal and placental hormone effects on appetite. To investigate the effect of leptin on food intake, d-9 pseudopregnant rats were injected with leptin (4 microg) via an intracerebroventricular (icv) cannula, and then food intake was measured 24 h later. Pseudopregnant rats were hyperphagic but had normal anorectic responses to leptin. We therefore hypothesized that a longer exposure time to high concentrations of progesterone might be required to mimic the leptin resistance that occurs on d 14 of pregnancy. Pseudopregnant rats were given progesterone to prolong pseudopregnancy beyond the time that leptin resistance develops during pregnancy. However, rats remained responsive to icv leptin. To model the placental lactogen secretion that occurs during pregnancy, pseudopregnant rats were given progesterone and chronic icv ovine prolactin infusion. Central icv injection of leptin had no effect on food intake in pseudopregnant rats receiving chronic ovine prolactin. These results suggest that chronically high lactogen levels, secreted by the placenta during the second half of pregnancy, induce central leptin resistance.

Lactogens promote beta cell survival through JAK2/STAT5 activation and Bcl-XL upregulation

One of the goals in the treatment for diabetes is to enhance pancreatic beta cell function, proliferation, and survival. This study explores the role of lactogenic hormones, prolactin (PRL) and placental lactogen (PL), in beta cell survival. We have previously shown that transgenic mice expressing mouse placental lactogen-1 (mPL1) in beta cells under the rat insulin II promoter (RIP) are resistant to the diabetogenic and cytotoxic effects of streptozotocin (STZ) in vivo. The current study demonstrates that lactogens protect rat insulinoma (INS-1) cells and primary mouse beta cells against two distinct beta cell death inducers, STZ and dexamethasone (DEX), in vitro. Further, we identify the mechanism through which lactogens protect beta cells against DEX-induced death. The signaling pathway mediating this protective effect is the janus-activated-kinase-2/signal transducer and activator of transcription-5 (JAK2/STAT5) pathway. This is demonstrated in INS-1 cells and primary mouse beta cells using three separate approaches, pharmacological inhibitors, JAK2-specific siRNAs and a dominant-negative STAT5 mutant. Furthermore, lactogens specifically and significantly increase the anti-apoptotic protein Bcl-XL in insulinoma cells and mouse islets. Bcl-XL-specific siRNA significantly inhibits lactogen-mediated protection against DEX-induced beta cell death. We believe this is the first direct demonstration of lactogens mediating their protective effect through the JAK2/STAT5 pathway in the beta cell and through Bcl-XL in any cell type.

Trophogram, an immunohistochemistry-based algorithmic approach, in the differential diagnosis of trophoblastic tumors and tumorlike lesions

Recent histopathologic and molecular studies of trophoblastic cells in the normal placenta and in a variety of trophoblastic diseases have revealed that the latter recapitulate the differentiation of normal trophoblast in the early developing placenta. This new knowledge, especially the identification and characterization of the protein markers expressed in human trophoblast, not only helps elucidate the pathogenesis of trophoblastic lesions but also provides a repertoire of immunohistochemical markers that may facilitate the diagnosis of various trophoblastic diseases. This article reviews the recent advances in the trophoblast-associated markers that have been reported to be useful in the differential diagnosis of trophoblastic tumors and tumorlike lesions. Moreover, a "trophogram," which is a stepwise and rational immunohistochemistry-based approach, will be introduced. The trophogram may prove to be useful in assisting the differential diagnosis of various trophoblastic diseases in diagnostic pathology.

Lysyl Oxidase Interacts with Hormone Placental Lactogen and Synergistically Promotes Breast Epithelial Cell Proliferation and Migration

Lysyl oxidase (LOX), an extracellular amine oxidase, catalyzes the cross-linking of collagen and elastin. LOX has been also shown to play an essential role in promoting the invasive and metastatic potential of breast tumor cells. However, the LOX-interacting factors in these processes are not known. In this study, we identified placental lactogen (PL), a member of the growth hormone/prolactin hormone family, as a LOX-interacting partner using yeast two-hybrid screens. PL is normally only expressed in placental syncytiotrophoblasts, but PL genes are amplified and expressed in a high percentage of invasive ductal breast carcinomas. We confirmed LOX-PL interactions using far Western and solid phase binding assays. In activity assays, PL was not a substrate or inhibitor of LOX. We further demonstrated that PL is expressed in breast tumor epithelial cells and detected LOX-PL interactions by coimmunoprecipitation in invasive breast cancer cells. In MCF-10A normal breast epithelial cells stably expressing LOX, PL, or both, LOX had no effect on cell proliferation, PL alone increased proliferation by 49%, and coexpression of LOX and PL led to a 121% increase in cell proliferation. Unlike in tumor cells, LOX did not induce a more migratory phenotype in MCF-10A cells; nor did PL. However, their coexpression resulted in a 240% increase in cell migration, suggesting that these interactions may be highly relevant to the transition of epithelial cells toward a migratory phenotype during the development and progression of breast carcinoma and a significant role for LOX-PL interactions in epithelial cell behavior.

[Clinicopathologic study of tumors of intermediate trophoblasts]

OBJECTIVE

To study the clinicopathologic features and immunophenotype of placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT).

METHODS

During the period from 1959 to 2005, a total of 1012 cases of gestational trophoblastic disease were diagnosed in Beijing Obstetrics and Gynecology Hospital. Six cases of PSTT and a case of ETT were retrieved from the archives of Beijing Obstetrics and Gynecology Hospital. Immunohistochemical study for cytokeratin 18, human chorionic gonadotropin (hCG), human placental lactogen (hPL), Mel-CAM (CD146), placental-like alkaline phosphatase (PLAP), epithelial membrane antigen (EMA), inhibin-alpha and proliferative cell nuclear antigen (PCNA) were performed. The morphologic features and immunohistochemical findings were compared with those of the controlled group which consisted of 20 cases of early gestational villi with decidua basalis and 20 cases of hydatidiform moles with implantation site.

RESULTS

The mean age of patients with PSTT was 32.4, while the age of patients with ETT was 36. Major clinical findings included irregular vaginal bleeding and amenorrhea. Preoperative serum hCG level varied from normal to moderately elevated. Serum testosterone level was raised in 1 case. Uterine curettage could achieve an accurate pathologic diagnosis in 60% of cases. ETT involved mainly the lower uterine segment and endocervix. Histologically, PSTT cells permeated between the myometrial fibers and vessels either individually or connecting in cords or sheets in a manner reminiscent of the implantation site reaction. ETT composed of a relatively uniform population of mononuclear trophoblastic cells, clumping together in nests as the cell islets associating with eosinophilic, fibrillary and hyaline material and necrotic debris, forming a "geographic map" like pattern. Immunohistochemical study for hPL, hCG, Mel-CAM (CD146) and PLAP was most helpful for the differential diagnosis. The duration of follow-up varied from 14 months to 19 years. One case of PSTT developed metastasis in pancreas, 5 months after the operation. The remaining patients survived without tumor recurrence.

CONCLUSIONS

PSTT is a tumor of implantation site intermediate trophoblasts while ETT differentiates towards chorionic-type intermediate trophoblasts. The different pathologic features and immunophenotype observed were closely related with the difference in tumor cell differentiation. An accurate pathologic diagnosis of the uterine curettage material is important for the clinical management. According to the limited follow-up data available, the clinical behavior of ETT is seemed similar to that of PSTT.

Structural and mechanistic studies on the inhibition of the hypoxia-inducible transcription factor hydroxylases by tricarboxylic acid cycle intermediates

In humans both the levels and activity of the alpha-subunit of the hypoxia-inducible transcription factor (HIF-alpha) are regulated by its post-translation hydroxylation as catalyzed by iron- and 2-oxoglutarate (2OG)-dependent prolyl and asparaginyl hydroxylases (PHD1-3 and factor-inhibiting HIF (FIH), respectively). One consequence of hypoxia is the accumulation of tricarboxylic acid cycle intermediates (TCAIs). In vitro assays were used to assess non-2OG TCAIs as inhibitors of purified PHD2 and FIH. Under the assay conditions, no significant FIH inhibition was observed by the TCAIs or pyruvate, but fumarate, succinate, and isocitrate inhibited PHD2. Mass spectrometric analyses under nondenaturing conditions were used to investigate the binding of TCAIs to PHD2 and supported the solution studies. X-ray crystal structures of FIH in complex with Fe(II) and fumarate or succinate revealed similar binding modes for each in the 2OG co-substrate binding site. The in vitro results suggest that the cellular inhibition of PHD2, but probably not FIH, by fumarate and succinate may play a role in the Warburg effect providing that appropriate relative concentrations of the components are achieved under physiological conditions.

Effect of leptin on the regulation of placental hormone secretion in cultured human placental cells

Placenta is an important source of leptin during pregnancy that contributes to the high plasma leptin levels in pregnant women. Leptin and its functional receptors are synthesized in trophoblast cells that, in turn, secrete gestational hormones supporting a paracrine or autocrine role for leptin in the endocrine activity of the placenta. In the present study we examined the effect of leptin on in vitro release of gestational hormones (human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogens and testosterone) by human term placental cells in culture. Placentas at term were obtained immediately after delivery from mothers with uncomplicated pregnancies. Progesterone, hCG, hPL, estradiol, estrone, estriol and testosterone levels were measured by different assays in culture media of cells maintained in monolayer culture after incubation for 12, 24, 48 or 72 h with leptin or placebo. Incubation with leptin did not modify hCG, hPL, progesterone, estriol and estrone secretion for any of the doses and times assayed. However, leptin led to a dose-dependent decrease in estradiol release. This effect was observed when treatment with recombinant human leptin spanned from 12 to 72 h. At this time an increase in testosterone levels was observed in leptin-treated cells versus placebo. These results indicate that leptin can be considered a gestational hormone implied in the endocrine function of the placenta, with an important role in control of the production of steroid reproductive hormones in placental cells in vitro.

Expression profiling of mouse placental lactogen II and its correlative genes using a cDNA microarray analysis in the developmental mouse placenta

The placenta is a highly differentiated organ essential for embryonic growth and development. In order to search for key molecules that are associated with mouse placental lactogen II (mPL-II) gene expression, we applied mouse cDNA microarray analysis to RNAs extracted from placentae on days 10, 12, 14, 16 and 18 of pregnancy. Changes in gene expression were categorized between days 10 and 12, 12 and 14, 14 and 16 and 16 and 18 of pregnancy. After microarray analysis, which had a minimum detectable fold change for differential expression of 2, we selected 10 genes, Apoa2, Apoc2, Ceacam14, Creg1, Fmo1, Igf2, Slc2a1, Spink3, Spi1-1 and Tpbpa, exhibiting a expression pattern similar to the mPL-II gene. Furthermore, we performed real-time PCR analysis and in situ hybridization (ISH) to find correlative expression genes for the mPL-II gene. From these results, we identified a resemblance in gene expression between mPL-II and Igf2 and selected these genes for performance of double-fluorescence immunohistochemical staining. We colocalized these proteins in labyrinthine trophoblast cells. These results strongly suggest that the expression of mPL-II and Igf2 is highly related to placental development in mice. This large-scale identification of genes regulated during placentogenesis assists in further elucidation of the molecular basis of extraembryonic development and function.

Molecular analysis of circulating RNA in plasma

Circulating RNA in plasma and serum is a newly developed area for molecular diagnosis. To date, increasing numbers of studies show that plasma and serum RNA could serve as both tumor- and fetal-specific markers for cancer detection and prenatal diagnosis, respectively. Recently, by introducing the highly sensitive one-step real-time quantitative reverse-transcription (RT)-polymerase chain reaction (PCR), these potentially valuable RNA species, which often only exist at low concentrations in plasma and serum, can now be readily detected and quantified. Following the successful quantification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in plasma of normal individuals, several placenta-derived mRNA species, including the mRNA transcripts of human placental lactogen (hPL), the beta-subunit of human chorionic gonadotropin (betahCG), and corticotropin-releasing hormone (CRH) were also quantified in plasma of pregnant women. These circulating placental RNA species have provided the fetal-polymorphism-independent markers for prenatal diagnosis. The achievement in detecting the placental RNA in maternal plasma represents a significant step toward the development of RNA markers for noninvasive prenatal gene expression profiling. This detection technique can be extended to access a wide range of disease conditions, such as cancer and trauma. The one-step, real-time quantitative RT-PCR is a highly sensitive and specific, yet practically simple, RNA detection technique. This powerful technology may allow the practical employment of circulating RNA in the high-throughput clinical screening and monitoring applications.

Syncytiotrophoblastic vesicles in placental intervillous space

OBJECTIVE

This study was undertaken to investigate the origin and function of vesicles found in the intervillous space.

STUDY DESIGN

A retrospective study was performed by using placental sections of different gestational ages. The number of vesicles was counted in each section of gestational age groups. Immunohistochemical staining for beta-human chorionic gonadotropin (beta-hCG) and human placental lactogen (hPL) was conducted to confirm the origin of vesicles.

RESULTS

Staining for beta-hCG and hPL was prominent in vesicles separating from syncytiotrophoblast into the intervillous space. The numbers of vesicles were not significantly different in gestational age groups of 42 to 30 weeks and all vesicles disappeared in 9- to 5-week groups. Large vesicles tended to show degeneration and disintegration in the intervillous space.

CONCLUSION

The vesicles containing beta-hCG and hPL suggest a different secretory mechanism of syncytiotrophoblast.

C-Reactive Protein Production in Term Human Placental Tissue

OBJECTIVE

C-reactive protein (CRP) is a marker of systemic inflammation. Recently, it has been shown that CRP is present in amniotic fluid and fetal urine, and that elevated levels are associated with adverse pregnancy outcome. However, the precise source of amniotic fluid CRP, its regulation, and function during pregnancy is still a matter of debate. The present in vivo and in vitro studies were designed to investigate the production of CRP in human placental tissues.

MATERIAL AND METHODS

Ten paired blood samples from peripheral maternal vein (MV), umbilical cord artery (UA) and umbilical vein (UV) were collected from women with elective caesarean sections at term. The placental protein accumulation capacity of hCG, hPL, leptin and CRP was compared with the dual in vitro perfusion method of an isolated cotyledon of human term placentae and quantified by ELISA. Values for accumulation (release) were calculated as total accumulation of maternal and fetal circuits normalized for tissue weight and duration of perfusion. For gene expression, RNA was extracted from placental tissue and reverse transcribed. RT-PCR and real-time PCR were performed using specific primers.

RESULTS

The median (range) CRP level was significantly different between UA and UV [50.1 ng/ml (12.1-684.6) vs. 61 ng/ml (16.9-708.1)]. The median (range) difference between UV and UA was 9.3 ng/ml (2.2-31.6). A significant correlation was found between MV CRP and both UA and UV CRP levels. Median (range) MV CRP levels [2649 ng/ml (260.1-8299)] were 61.2 (6.5-96.8) fold higher than in the fetus. In vitro, the total accumulation rates (mean+/-SD) were 31+/-13 (mU/g/min, hCG), 1.16+/-0.19 (microg/g/min, hPL), 4.71+/-1.91 (ng/g/min, CRP), and 259+/-118 (pg/g/min, leptin). mRNA for hCG, hPL and leptin was detectable using conventional RT-PCR, while CRP mRNA could only be demonstrated by applying real-time RT-PCR. In the perfused tissue the transcript levels for the four proteins were comparable to those detected in the native control tissue.

CONCLUSIONS

Our results demonstrate that the human placenta produces and releases CRP mainly into the maternal circulation similarly to other analyzed placental proteins under in vitro conditions. Further studies are needed to explore the exact role of placental CRP during pregnancy.

Crystal Structure and Site 1 Binding Energetics of Human Placental Lactogen

In primates, placental lactogen (PL) is a pituitary hormone with fundamental roles during pregnancy involving fetal growth, metabolism, and stimulating lactation in the mother. Human placental lactogen (hPL) is highly conserved with human growth hormone (hGH) and both hormones bind to the hPRLR extracellular domain (ECD), the first step in receptor homodimerization, in a Zn2+-dependent manner. A modified surface plasmon resonance method was developed to measure the kinetics for hPL and hGH binding to the hPRLR ECD, with and without Zn2+ and showed that hPL has about a tenfold higher affinity for the hPRLR ECD1 than hGH. The crystal structure of the free state of hPL has been determined to 2.0 A resolution showing the molecule possesses an overall structure similar to other long chain four-helix bundle cytokines. Comparison of the free hPL structure with the 1:1 complex structure of hGH bound to the hPRLR ECD1 suggests that two surface loops undergo conformational changes >10 A upon binding. An 18 residue Ala-scan was used to characterize the binding energy epitope for the site 1 interface of hPL. Individual alanine substitutions at five positions reduced binding affinity by a DeltaDeltaG > or = 3 kcal mol(-1). A comparison of the hPL site 1 epitope with that previously determined for hGH indicates contributions of individual residues track reasonably well between hPL and hGH. In particular, residues involved in the zinc-binding site and Lys172 constitute the principal binding determinants for both hormones. However, several residues that are identical between hPL and hGH contribute quite differently to the binding of the hPRLR ECD1. Additionally, the overall magnitudes of the DeltaDeltaG changes observed from the Ala-scan of hPL were markedly larger than those determined in the comparative scan of hGH to the hPRLR ECD1. The structural and biophysical data presented here show that subtle changes in the structural context of an interaction can lead to significantly different effects at the individual residue level.

The Transcription Factor PLA-1/SKN-1A is Expressed in Human Placenta and Regulates the Placental Lactogen-3 Gene Expression

Here we report the selective expression of two POU transcription factor genes, PLA-1 and OCT-1, in human placenta and choriocarcinoma cell lines JAR, JEG-3 and BeWo. Pla-1 protein binds to a POU-consensus DNA sequence in the human placental lactogen-3 (PL-3) promoter and it is capable of trans-activating its transcription up to 18-fold. Other tissue-specific or ubiquitous POU transcription factors such as Pit-1/GHF-1 or Oct-1 showed none or low levels of trans-activation of the PL-3 promoter. In addition, we identified an unique and highly charged region in the N-terminal portion of Pla-1 protein required for full trans-activation of the PL-3 promoter.

Src family kinases play multiple roles in differentiation of trophoblasts from human term placenta

Tyrosine phosphorylation plays a major role in controlling many biological processes in different cell types. Src family kinases (SFKs) are one of the most studied groups of tyrosine kinases and can mediate a variety of signalling pathways. However, little is known about the expression of SFKs in human term placenta and their implication in trophoblast differentiation. Therefore, we examined the expression profile of SFK members over time in culture and their implication in differentiation. In vitro, freshly isolated cytotrophoblast cells, cultured in 10% fetal bovine serum (FBS), spontaneously aggregate and fuse to form multinucleated cells that resemble phenotypically mature syncytiotrophoblasts, that concomitantly produce human chorionic gonadotropin (hCG) and human placental lactogen (hPL). In this study, we showed that trophoblasts expressed all SFK members and some of them are expressed as different splice variants. Moreover, using real-time PCR, this study showed two different expression profiles of SFKs in human trophoblasts during culture. In addition, the protein level and phosphorylation status of Src were evaluated using specific antibodies. Src was rapidly phosphorylated at Tyr-416 and dephosphorylated at Tyr-527 after FBS addition. Surprisingly, inhibition of SFKs by 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2) or herbimycin A had different effects on trophoblast differentiation. While herbimycin A inhibited morphological and hormonal differentiation, PP2 stimulated hormonal differentiation and inhibited cell adhesion and spreading with no effect on cell fusion. In summary, this study showed that SFKs play different roles in trophoblast differentiation, probably depending on SFK members activated. Thus, this study increases our knowledge and understanding of pathology related to impaired trophoblast differentiation such as pre-eclampsia and trophoblast neoplasm.

Evaluation of beta-cell replication in mice transgenic for hepatocyte growth factor and placental lactogen: comprehensive characterization of the G1/S regulatory proteins reveals unique involvement of p21cip

We hypothesized that combined transgenic overexpression of hepatocyte growth factor (HGF) and placental lactogen in islets would lead to even greater increases in beta-cell mass and replication than either growth factor alone. This did not occur, suggesting that beta-cell replication is saturable or subject to molecular restraint. We therefore performed the first comprehensive G(1)/S cell cycle survey in islets, cataloguing the broad range of kinases, cyclins, and kinase inhibitors that control the G(1)/S transition in islets from normal, HGF, placental lactogen, and doubly transgenic mice. Many of the G(1)/S checkpoint regulators (E2Fs; pRb; p107; p130; cyclins D(1),(2),(3), A, and E; cdk-2; cdk-4; p15; p16; p18; p19; p21; p27; MDM2; p53; c-Myc; and Egr-1) are present in the murine islet. Most of these proteins were unaltered by overexpression of HGF or placental lactogen, either alone or in combination. In contrast, p21(cip) was uniquely, dramatically, and reproducibly upregulated in placental lactogen and HGF islets. p21(cip) was also present in, and upregulated in, proliferating human islets, localizing specifically in beta-cells and translocating to the nucleus on mitogenic stimulation. Homozygous p21(cip) loss releases islets from growth inhibition, markedly enhancing proliferation in response to HGF and placental lactogen.

Effect of IPs, cAMP, and cGMP on the hPL and hCG secretion from human term placenta

The acute control of human placental lactogen (hPL) and chorionic gonadotrophin (hCG) secretion by the placenta remains elusive. The in vitro release of both hormones can be stimulated by calcium inflow and by albumin. To investigate the placental secretory response to putative ligand(s) present in the maternal circulation, we evaluated the coupling of the hPL and hCG releases from term placenta with intracellular signaling pathways. Addition of NaF, forskolin or sodium nitroprusside, activators of the inositol phosphates (IPs), cAMP and cGMP pathways, significantly increased their respective messengers in villous explants but failed to affect the hPL and hCG releases from syncytiotrophoblast. By contrast, albumin did not modify the IPs, cAMP and cGMP villous content but significantly stimulated the placental hormonal release. These data suggest that the hPL and hCG secretion is not regulated through the IPs, cAMP and cGMP signaling pathways.

Temporospatial expression of placental lactogen and prolactin-related protein-1 genes in the bovine placenta and uterus during pregnancy

The anatomical location of binucleate cells (BNC) influences protein expression but not steroid synthesis in ruminants. In order to determine if BNC in disparate locations differentially express bovine placental lactogen (bPL) and prolactin-related protein-1 (bPRP-1), we quantitated bPL and bPRP-1 transcripts in placentomal (cotyledonary, caruncular) and interplacentomal (intercotyledonary, intercaruncular) tissues throughout pregnancy in the bovine using real-time reverse transcription PCR (RT-PCR) and in situ hybridization. Levels of both bPL and bPRP-1 transcripts at peri-implantation were significantly higher (P < 0.01) in the fetal membrane than in caruncular and intercaruncular tissues. Thereafter, mRNA for these related proteins demonstrated different spatial as well as temporal patterns of expression. Levels of bPRP-1 transcripts peaked at day 60 of pregnancy. Between day 60 and 100, bPRP-1 transcripts fell by approximately sevenfold (P < 0.01) in cotyledonary and intercotyledonary tissues, and fourfold in caruncular (P < 0.01) tissue. Levels of bPRP-1 transcripts remained low in the cotyledonary, intercotyledonary, and caruncular tissues until peripartum. In contrast, bPL expression in placentomes increased with progression of gestation (P < 0.01), but decreased in interplacentomal tissue around peripartum. To conclude, disparate patterns of bPRP-1 and bPL genes are transcribed in the placentomal and interplacentomal tissues during gestation in the bovine, suggesting that these prolactin-like hormones serve distinct functions and are regulated differently in the uteroplacental unit in this species.

Hepatocyte nuclear factor-3alpha binding at P sequences of the human growth hormone locus is associated with pituitary repressor function

The human GH family consists of five genes, including the placental chorionic somatomammotropins (CS), within a single locus on chromosome 17. Based on nuclease sensitivity, the entire GH/CS locus is accessible in pituitary chromatin, yet only GH-N is expressed. Previously, we reported a P sequence element (263P) capable of repressing placental CS-A promoter activity in transfected pituitary (GC) cells, and our data indicated a possible role for nuclear factor-1 (NF-1) and regulatory factor X1 in this repression. In this study we show the formation of two independent pituitary complexes in vitro: a repressor complex containing NF-1 and a nonfunctional complex containing regulatory factor X1. In vitro repressor function is stabilized by the presence of P sequence element C (PSE-C), downstream of the previously characterized PSE-A and PSE-B. Repressor function is also dependent on an intact Pit-1 binding site in the CS-A promoter. EMSAs with PSE-C reveal binding of the hepatocyte nuclear factor-3/forkhead (HNF-3/fkh) family of transcription factors in rat pituitary GC cells. This observation is extended to human pituitary tissue, where HNF-3alpha's association with P sequences is confirmed by chromatin immunoprecipitation. Furthermore, protein-protein interactions between HNF-3alpha and NF-1 family members are demonstrated. These results identify HNF-3alpha as an additional member of the pituitary P sequence regulatory complex, implicating it in tissue-specific expression of the human GH/CS family.

Regulation of embryo outgrowth by a morphogenic factor, epimorphin, in the mouse

Conceptus implantation to the uterine endometrium represents a complex series of events, including synchronized development of conceptus and uterus through up- and/or down-regulation of numerous gene products. In a previous study using the DNA microarray technique, we had discovered evidence that increase in a transcript for mesenchymal morphogen, epimorphin, was noted as the conceptus attached to the matrix in vitro (Qin et al., 2003). In the present study, the expression and potential function of epimorphin in developing conceptuses was investigated through the use of reverse transcription-polymerase chain reaction (RT-PCR), whole mount in situ hybridization/immunohistochemistry, and in vitro blastocyst culture. RT-PCR and in situ hybridization analysis revealed that epimorphin mRNA was expressed weakly in murine conceptuses during early developmental stages (1 cell to post-adhesion blastocyst stages) and higher levels of epimorphin transcripts were observed in both inner cell mass (ICM) and trophectoderm of outgrowing blastocysts. Immunohistochemical analysis confirmed that epimorphin was localized in outgrowing trophoblast cells and ICM. Treating blastocysts in culture with a 115 kDa form of recombinant epimorphin promoted trophoblast outgrowth (P < 0.05), but a 34 kDa form of recombinant epimorphin had no effect. Treatment with a function inhibitor, rat anti-mouse epimorphin IgM, reduced the number of embryos progressing to blastocyst outgrowth to the levels similar to those observed with plain culture medium. Reverse transcription-polymerase chain reaction (RT-PCR) analysis also revealed that epimorphin increased the expression of a trophoblast cell differentiation marker, placental lactogen-1 (PL-1), mRNA (P < 0.01). These results suggest that epimorphin is involved in trophoblast outgrowth, a process required for conceptus implantation into the endometrium.

Regulatory role of hepatocyte nuclear factor-4alpha on gastric choriocarcinoma function

Gastric choriocarcinoma is a highly aggressive carcinoma, most probably originating from somatic cells in the gastric mucosal layer. We herein investigated the regulatory role of hepatocyte nuclear factor (HNF)-4alpha, a transcriptional regulator expressed in non-neoplastic and neoplastic gastric tissues, on functions of gastric choriocarcinoma cells. HNF-4alpha cDNA was stably transfected to a gastric choriocarcinoma cell line, SCH. Alterations in SCH cell functions such as histology, ultrastructure, proliferation, production of trophoblast-specific proteins, and chemosensitivity to methotrexate (MTX) were examined. Neither in vitro and in vivo proliferations nor HLA-G expression differed significantly between the mock-transfected and HNF-4alpha-transfected SCH cells, while suppressed human chorionic gonadotropin (hCG) secretions, increased human placental lactogen (hPL) and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) immunoreactivity, and decreased chemosensitivity to MTX were seen in HNF-4alpha-transfected SCH cells. General histologic features in xenograft nodules were unaltered, but, ultrastructurally, fascicles of paranuclear filaments were significantly more numerous in HNF-4alpha-transfected SCH cells. These results indicated an HNF-4alpha-rendered functional regulation in SCH cells, suggesting a role of transcriptional factors abundant in gastric but not in trophoblastic tissues/cells on the functional modulation of gastric choriocarcinoma cells.