HtrA4 is well conserved only in higher primates and functionally important for EVT differentiation

INTRODUCTION

The placenta differs greatly among species, and deep extra-villous trophoblast (EVT) invasion is a unique feature of placentation of higher primates including humans. We reported serine protease HtrA4 being found predominantly in human placentas with aberrant expression linked to preeclampsia. However, it remains unclear where HtrA4 is produced in the placenta, how it is expressed in other species, and whether it is essential for human placentation.

METHODS

We first compared HtrA4 protein sequences of over 100 species, then scrutinized the key characteristics of HtrA4 in the human, rhesus macaque and mouse, and determined cellular localization in the placenta. We next investigated functional significance of HtrA4 in EVT differentiation using human trophoblast stem cells (TSCs).

RESULTS

Across broader species HtrA4 is well conserved only in higher primates. In humans, only the placenta expressed HtrA4, localising to trophoblasts of villous as well as extra-villous lineages. Rhesus macaques produced HtrA4 but again only in placentas, whereas mice showed no abundant HtrA4 expression anywhere including the placenta, yet it was an active protease if produced. The functional importance of HtrA4 in human EVT was demonstrated using TSCs, which expressed low levels of HtrA4 but significantly up-regulated it during EVT differentiation, and knockdown of HtrA4 severely inhibited the differentiation process.

DISCUSSION

HtrA4 is expressed in placentas of humans and macaques but not mice; it is critical for human EVT differentiation. Together with previous reports showing HtrA4 is also indispensable for syncytialization, this study further revealed HtrA4 as a functionally important protease for human placentation.

Podocalyxin promotes the formation of compact and chemoresistant cancer spheroids in high grade serous carcinoma

High grade serous carcinoma (HGSC) metastasises primarily intraperitoneally via cancer spheroids. Podocalyxin (PODXL), an anti-adhesive transmembrane protein, has been reported to promote cancer survival against chemotherapy, however its role in HGSC chemoresistance is unclear. This study investigated whether PODXL plays a role in promoting chemoresistance of HGSC spheroids. We first showed that PODXL was expressed variably in HGSC patient tissues (n = 17) as well as in ovarian cancer cell lines (n = 28) that are more likely categorised as HGSC. We next demonstrated that PODXL-knockout (KO) cells proliferated more slowly, formed less compact spheroids and were more fragile than control cells. Furthermore, when treated with carboplatin and examined for post-treatment recovery, PODXL-KO spheroids showed significantly poorer cell viability, lower number of live cells, and less Ki-67 staining than controls. A similar trend was also observed in ascites-derived primary HGSC cells (n = 6)-spheroids expressing lower PODXL formed looser spheroids, were more vulnerable to fragmentation and more sensitive to carboplatin than spheroids with higher PODXL. Our studies thus suggests that PODXL plays an important role in promoting the formation of compact/hardy HGSC spheroids which are more resilient to chemotherapy drugs; these characteristics may contribute to the chemoresistant nature of HGSC.

HtrA4 is required for human trophoblast stem cell differentiation into syncytiotrophoblast

INTRODUCTION

The syncytiotrophoblast (STB) of the human placenta facilitates vital maternal-fetal communication and is maintained by fusion (syncytialization) of cytotrophoblasts. Serine protease HtrA4 (high temperature requirement factor A4) is highly expressed only in the human placenta and was previously reported to be important for BeWo fusion. This study investigated whether HtrA4 is critical for differentiation of human trophoblast stem cells (TSCs) into STB.

METHODS

Primary TSCs were isolated from first trimester placentas (n = 5) and validated by immunofluorescence (IF) for CD49f, CK7 and vimentin. TSCs were then differentiated into STB and the success of syncytialization was confirmed by RT-PCR, IF and ELISA of known markers. TSCs were next stably transfected with a HtrA4-targetting CRISPR/Cas9 plasmid, and cells with severe HtrA4 knockdown (HtrA4-KD) were analyzed to investigate the impact on STB differentiation.

RESULTS

Primary TSCs were confirmed to be of high purity by staining positively for CD49f and CK7 but negatively for vimentin. These TSCs readily syncytialized when stimulated for STB differentiation, significantly increasing β-hCG and syncytin-1, substantially decreasing E-cadherin, and markedly losing cell borders. While TSCs produced very low levels of HtrA4, upon stimulation for STB differentiation the cells drastically upregulated HtrA4 expression; secretion of HtrA4 protein also increased sharply, correlating positively and significantly with that of β-hCG. The HtrA4-KD TSCs, however, failed to show this surge of HtrA4 production upon stimulation, and ultimately remained primarily mononucleated with no significant STB differentiation.

DISCUSSION

This study demonstrates that HtrA4 plays a critical role in TSC differentiation into syncytiotrophoblast.

Acupuncture and Chinese herbal medicine for menopausal mood disorder: a randomized controlled trial

OBJECTIVE

This study aimed to analyze the effectiveness of acupuncture combined with Chinese herbal medicine (CHM) on mood disorder symptoms for menopausal women.

METHODS

A total of 95 qualified Chinese participants were randomly assigned to one of three groups: 31 in the acupuncture combined with CHM group (combined group), 32 in the acupuncture combined with CHM placebo group (acupuncture group) and 32 in the CHM combined with sham acupuncture group (CHM group). The patients were treated for 8 weeks and followed up for 4 weeks. The data were collected using the Greene Climacteric Scale (GCS), self-rating depression scale (SDS), self-rating anxiety scale (SAS) and safety index.

RESULTS

The three groups each showed significant decreases in the GCS, SDS and SAS after treatment (p < 0.05). Furthermore, the effect on the GCS total score and the anxiety domain lasted until the follow-up period in the combined group (p < 0.05). Within the three groups, there was no difference in GCS and SAS between the three groups after treatment (p > 0.05). However, the combined group showed significant improvement in the SDS, compared with both the acupuncture group and the CHM group at 8 weeks and 12 weeks (p < 0.05). No obvious abnormal cases were found in any of the safety indexes.

CONCLUSIONS

The results suggest that either acupuncture, or CHM or combined therapy offer safe improvement of mood disorder symptoms for menopausal women. However, the combination therapy was associated with more stable effects in the follow-up period and a superior effect on improving depression symptoms.

A placental model of SARS-CoV-2 infection reveals ACE2-dependent susceptibility and differentiation impairment in syncytiotrophoblasts

SARS-CoV-2 infection causes COVID-19. Several clinical reports have linked COVID-19 during pregnancy to negative birth outcomes and placentitis. However, the pathophysiological mechanisms underpinning SARS-CoV-2 infection during placentation and early pregnancy are not clear. Here, to shed light on this, we used induced trophoblast stem cells to generate an in vitro early placenta infection model. We identified that syncytiotrophoblasts could be infected through angiotensin-converting enzyme 2 (ACE2). Using a co-culture model of vertical transmission, we confirmed the ability of the virus to infect syncytiotrophoblasts through a previous endometrial cell infection. We further demonstrated transcriptional changes in infected syncytiotrophoblasts that led to impairment of cellular processes, reduced secretion of HCG hormone and morphological changes vital for syncytiotrophoblast function. Furthermore, different antibody strategies and antiviral drugs restore these impairments. In summary, we have established a scalable and tractable platform to study early placental cell types and highlighted its use in studying strategies to protect the placenta.

Detrimental actions of obesity-associated advanced glycation end-products on endometrial epithelial cell proliferation are alleviated by antioxidants

RESEARCH QUESTION

Advanced glycation end-products (AGE) are elevated in the uterine environment of obese infertile women. Can the detrimental effects of AGE on endometrial epithelial cells be mitigated with therapeutics, and recapitulated in a more physiologically relevant primary model (organoids)?

DESIGN

Human endometrial epithelial cells (ECC-1) were exposed to AGE at concentrations physiologically representative of uterine fluid in lean or obese individuals, and three potential therapeutics: 25 nmol/l receptor for AGE (RAGE) antagonist FPS-ZM1, 100 μmol/l metformin, or a combination of antioxidants (10 μmol/l N-acetyl-l-cysteine, 10 μmol/l N-acetyl-l-carnitine and 5 μmol/l α-lipoic acid). Real-time cell analysis (xCELLigence, ACEA Biosciences) determined the rate of adhesion and proliferation. The proliferation of organoid-derived cells and secretion of cytokines from organoids was characterized in the presence of AGE (n = 5). The uterine fluid of women undergoing assisted reproduction was profiled for AGE-associated inflammatory markers (n = 77).

RESULTS

ECC-1 proliferation was reduced by AGE from obese versus lean conditions and vehicle control (P = 0.04 and P < 0.001, respectively), and restored to a proliferation corresponding to lean conditions by antioxidants. AGE influenced organoid derived primary endometrial epithelial cell proliferation in a donor-dependent manner. AGE increased the organoid secretion of the proinflammatory cytokine CXCL16 (P = 0.006). Clinically, CXCL16 correlated positively to maternal body mass index (R = 0.264, P = 0.021) and intrauterine glucose concentration (R = 0.736, P < 0.0001).

CONCLUSIONS

Physiologically relevant concentrations of AGE alter endometrial epithelial cell function. Antioxidants restore the rate of proliferation of AGE-treated endometrial epithelial (ECC-1) cells. Primary endometrial epithelial cells, cultured as organoids, demonstrate altered proliferation and CXCL16 secretion in the presence of AGE equimolar with the uterine fluid from obese individuals.

Progesterone suppresses podocalyxin partly by up-regulating miR-145 and miR-199 in human endometrial epithelial cells to enhance receptivity in in-vitro models

Establishment of endometrial surface receptivity is crucial for the initiation of embryo implantation, yet the molecular mechanisms are not well understood especially in the human. We have recently discovered that podocalyxin (PODXL) is a critical negative regulator of human endometrial surface receptivity. PODXL is highly expressed in all epithelial and endothelial cells in the non-receptive endometrium, but down-regulated specifically in the luminal epithelium at receptivity. We have further shown that PODXL inhibits embryo implantation, and that PODXL down-regulation is essential for endometrial surface receptivity. Our previous study also indicated that progesterone down-regulates PODXL, however, the exact molecular regulations are unknown. Here we investigated whether progesterone suppresses PODXL via microRNAs (miRNAs). We first bioinformatically predicted 13 miRNAs that may potentially target human PODXL, then experimentally determined whether any of these 13 miRNAs are altered in primary human endometrial epithelial cells (HEECs) by progesterone, and whether the identified miRNAs can affect PODXL expression in Ishikawa cells without progesterone and alter receptivity to embryo implantation. Progesterone significantly up-regulated miR-145 and miR-199 while suppressing PODXL in HEECs. When these two miRNAs were transfected into Ishikawa cells, both significantly down-regulated PODXL mRNA and protein in the absence of progesterone. Moreover, both miR-145 and miR-199 significantly enhanced receptivity of the Ishikawa monolayer to embryo implantation in in-vitro models. This study thus provides in-vitro evidence that PODXL is down-regulated by progesterone partly via miR-145 and miR-199 during the development of human endometrial epithelial receptivity. These results also reveal the likely importance of hormonal regulation of microRNAs for embryo implantation.

MicroRNAs in the Regulation of Endometrial Receptivity for Embryo Implantation

Development of endometrial receptivity is crucial for successful embryo implantation and pregnancy initiation. Understanding the molecular regulation underpinning endometrial transformation to a receptive state is key to improving implantation rates in fertility treatments such as IVF. With microRNAs (miRNAs) increasingly recognized as important gene regulators, recent studies have investigated the role of miRNAs in the endometrium. Studies on miRNAs in endometrial disorders such as endometriosis and endometrial cancer have been reviewed previously. In this minireview, we aim to provide an up-to-date knowledge of miRNAs in the regulation of endometrial receptivity. Since endometrial remodelling differs considerably between species, we firstly summarised the key events of the endometrial cycle in humans and mice and then reviewed the miRNAs identified so far in these two species with likely functional significance in receptivity establishment. To date, 29 miRNAs have been reported in humans and 15 miRNAs in mice within various compartments of the endometrium that may potentially modulate receptivity; miRNAs regulating the Wnt signalling and those from the let-7, miR-23, miR-30, miR-200 and miR-183 families are found in both species. Future studies are warranted to investigate miRNAs as biomarkers and/or therapeutic targets to detect/improve endometrial receptivity in human fertility treatment.

Podocalyxin molecular characteristics and endometrial expression: high conservation between humans and macaques but divergence in mice†

Podocalyxin (PODXL) is a newly identified key negative regulator of human endometrial receptivity, specifically down-regulated in the luminal epithelium at receptivity to permit embryo implantation. Here, we bioinformatically compared the molecular characteristics of PODXL among the human, rhesus macaque and mouse, determined by immunohistochemistry and in situ hybridization (mouse tissues) whether endometrial PODXL expression is conserved across the three species, and examined if PODXL inhibits mouse embryo attachment in vitro. The PODXL gene, mRNA and protein sequences showed greater similarities between humans and macaques than with mice. In all species, PODXL was expressed in endometrial luminal/glandular epithelia and endothelia. In macaques (n = 9), luminal PODXL was significantly down-regulated when receptivity is developed, consistent with the pattern found in women. At receptivity PODXL was also reduced in shallow glands, whereas endothelial expression was unchanged across the menstrual cycle. In mice, endometrial PODXL did not vary considerably across the estrous cycle (n = 16); however, around embryo attachment on d4.5 of pregnancy (n = 4), luminal PODXL was greatly reduced especially near the site of embryo attachment. Mouse embryos failed to attach or thrive when co-cultured on a monolayer of Ishikawa cells overexpressing PODXL. Thus, endometrial luminal PODXL expression is down-regulated for embryo implantation in all species examined, and PODXL inhibits mouse embryo implantation. Rhesus macaques share greater conservations with humans than mice in PODXL molecular characteristics and regulation, thus represent a better animal model for functional studies of endometrial PODXL for treatment of human fertility.

Podocalyxin promotes an impermeable epithelium and inhibits pro-implantation factors to negatively regulate endometrial receptivity

Embryo implantation is a key step in establishing pregnancy and a major limiting factor in IVF. Implantation requires a receptive endometrium but the mechanisms governing receptivity are not well understood. We have recently discovered that podocalyxin (PCX or PODXL) is a key negative regulator of human endometrial receptivity. PCX is expressed in all endometrial epithelial cells in the non-receptive endometrium but selectively down-regulated in the luminal epithelium at receptivity. We have further demonstrated that this down-regulation is essential for implantation because PCX inhibits embryo attachment and penetration. However, how PCX confers this role is unknown. In this study, through RNAseq analysis of Ishikawa cell line stably overexpressing PCX, we discovered that PCX suppresses expression of genes controlling cell adhesion and communication, but increases those governing epithelial barrier functions, especially the adherens and tight junctions. Moreover, PCX suppresses multiple factors such as LIF and signaling pathways including Wnt and calcium signaling that support receptivity but stimulates anti-implantation genes such as LEFTY2. Functional studies confirmed that PCX promotes epithelial barrier functions by increasing key epithelial junction proteins such as E-cadherin and claudin 4. PCX thus promotes an anti-adhesive and impermeable epithelium while impedes pro-implantation factors to negatively control endometrial receptivity for implantation.

Podocalyxin inhibits human embryo implantation in vitro and luminal podocalyxin in putative receptive endometrium is associated with implantation failure in fertility treatment

OBJECTIVE

To study whether endometrial epithelial podocalyxin (PCX) inhibits implantation of human embryos in vitro and in patients undergoing in vitro fertilization (IVF).

DESIGN

We have recently identified PCX as a key negative regulator of endometrial epithelial receptivity. Podocalyxin is expressed in all epithelial cells in the nonreceptive endometrium, but is selectively downregulated in the luminal epithelium (LE) for receptivity. In the current study, we first investigated whether high levels of PCX in Ishikawa monolayer inhibit attachment and/or penetration of human blastocysts in in vitro models. We then examined PCX by immunohistochemistry in putative receptive endometrial tissues biopsied from 81 IVF patients who underwent frozen embryo transfer in the next natural cycle and retrospectively analyzed the association between PCX staining in LE and clinical pregnancy as a proxy of successful implantation.

SETTING

RMIT University, Australia; Vrije Universiteit Brussel, Belgium.

PATIENT(S)

In vitro fertilization patients undergoing frozen/thawed embryo transfer.

INTERVENTION(S)

N/A.

MAIN OUTCOME MEASURE(S)

Endometrial epithelial PCX inhibits implantation of human embryos in vitro and in IVF patients.

RESULT(S)

High levels of PCX in Ishikawa monolayer significantly inhibited blastocyst attachment and penetration. Among the 81 putative receptive tissues, 73% were negative, but 27% were heterogeneously positive for PCX in LE. The clinical pregnancy rate was 53% in those with a PCX-negative LE but only 18% in those with a PCX-positive LE. If LE was positive for PCX, the odds ratio of no clinical pregnancy was 4.95 (95% Confidence interval, 1.48-14.63).

CONCLUSION(S)

Podocalyxin inhibits embryo implantation. Assessment of PCX may aid the evaluation and optimization of endometrial receptivity in fertility treatment.

Podocalyxin is a key negative regulator of human endometrial epithelial receptivity for embryo implantation

STUDY QUESTION

How is endometrial epithelial receptivity, particularly adhesiveness, regulated at the luminal epithelial surface for embryo implantation in the human?

SUMMARY ANSWER

Podocalyxin (PCX), a transmembrane protein, was identified as a key negative regulator of endometrial epithelial receptivity; specific downregulation of PCX in the luminal epithelium in the mid-secretory phase, likely mediated by progesterone, may act as a critical step in converting endometrial surface from a non-receptive to an implantation-permitting state.

WHAT IS KNOWN ALREADY

The human endometrium must undergo major molecular and cellular changes to transform from a non-receptive to a receptive state to accommodate embryo implantation. However, the fundamental mechanisms governing receptivity, particularly at the luminal surface where the embryo first interacts with, are not well understood. A widely held view is that upregulation of adhesion-promoting molecules is important, but the details are not well characterized.

STUDY DESIGN, SIZE, DURATION

This study first aimed to identify novel adhesion-related membrane proteins with potential roles in receptivity in primary human endometrial epithelial cells (HEECs). Further experiments were then conducted to determine candidates' in vivo expression pattern in the human endometrium across the menstrual cycle, regulation by progesterone using cell culture, and functional importance in receptivity using in vitro human embryo attachment and invasion models.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Primary HEECs (n = 9) were isolated from the proliferative phase endometrial tissue, combined into three pools, subjected to plasma membrane protein enrichment by ultracentrifugation followed by proteomics analysis, which led to the discovery of PCX as a novel candidate of interest. Immunohistochemical analysis determined the in vivo expression pattern and cellular localization of PCX in the human endometrium across the menstrual cycle (n = 23). To investigate whether PCX is regulated by progesterone, the master driver of endometrial differentiation, primary HEECs were treated in culture with estradiol and progesterone and analyzed by RT-PCR (n = 5) and western blot (n = 4). To demonstrate that PCX acts as a negative regulator of receptivity, PCX was overexpressed in Ishikawa cells (a receptive line) and the impact on receptivity was determined using in vitro attachment (n = 3-5) and invasion models (n = 4-6), in which an Ishikawa monolayer mimicked the endometrial surface and primary human trophoblast spheroids mimicked embryos. Mann-Whitney U-test and ANOVA analyses established statistical significance at *P ≤ 0.05 and **P ≤ 0.01.

MAIN RESULTS AND THE ROLE OF CHANCE

PCX was expressed on the apical surface of all epithelial and endothelial cells in the non-receptive endometrium, but selectively downregulated in the luminal epithelium from the mid-secretory phase coinciding with the establishment of receptivity. Progesterone was confirmed to be able to suppress PCX in primary HEECs, suggesting this hormone likely mediates the downregulation of luminal PCX in vivo for receptivity. Overexpression of PCX in Ishikawa monolayer inhibited not only the attachment but also the penetration of human embryo surrogates, demonstrating that PCX acts as an important negative regulator of epithelial receptivity for implantation.

LIMITATIONS, REASONS FOR CAUTION

Primary HEECs isolated from the human endometrial tissue contained a mixture of luminal and glandular epithelial cells, as further purification into subtypes was not possible due to the lack of specific markers. Future study would need to investigate how progesterone differentially regulates PCX in endometrial epithelial subtypes. In addition, this study used primary human trophoblast spheroids as human embryo mimics and Ishikawa as endometrial epithelial cells in functional models, future studies with human blastocysts and primary epithelial cells would further validate the findings.

WIDER IMPLICATIONS OF THE FINDINGS

The findings of this study add important new knowledge to the understanding of human endometrial remodeling for receptivity. The identification of PCX as a negative regulator of epithelial receptivity and the knowledge that its specific downregulation in the luminal epithelium coincides with receptivity development may provide new avenues to assess endometrial receptivity and individualize endometrial preparation protocols in assisted reproductive technology (ART). The study also discovered PCX as progesterone target in HEECs, identifying a potentially useful functional biomarker to monitor progesterone action, such as in the optimization of progesterone type/dose/route of administration for luteal support.

STUDY FUNDING/COMPETING INTEREST(S)

Study funding was obtained from ESHRE, Monash IVF and NHMRC. LR reports potential conflict of interests (received grants from Ferring Australia; personal fees from Monash IVF Group and Ferring Australia; and non-financial support from Merck Serono, MSD, and Guerbet outside the submitted work. LR is also a minority shareholder and the Group Medical Director for Monash IVF Group, a provider of fertility preservation services). The remaining authors have no potential conflict of interest to declare.

TRIAL REGISTRATION NUMBER

NA.

Second and third trimester serum levels of HtrA1 in pregnancies affected by pre-eclampsia

INTRODUCTION

Altered placental expression of high temperature requirement factor A1 (HtrA1) is implicated in abnormal trophoblastic invasion and endothelial dysfunction in pre-eclampsia (PE). Serum levels of HtrA1 have been proposed as a novel biomarker to improve the prediction of PE. This study assesses serum HtrA1 levels in prospectively collected samples of women who developed PE compared to normotensive pregnancies.

METHODS

This was a case-control study of serum HtrA1 levels in second and third trimester samples in women who later developed preterm or term PE compared to controls. Overall, 300 serum samples were drawn from a prospective observational study of adverse pregnancy outcomes in three different gestational age windows (19-24, 30-34 and 35-37 weeks) at the Fetal Medicine Research Institute, King's College Hospital, London. Serum HtrA1 levels were determined by enzyme-linked immunosorbent assay (ELISA) by a blinded laboratory professional. Median HtrA1 MoM values, adjusted for gestational age and maternal characteristics, were compared between cases and controls at each gestational age group.

RESULTS

Women who later developed PE, compared to controls, had significantly higher maternal weight and more frequently had chronic hypertension or a history of PE in a previous pregnancy. In normotensive pregnancies, serum HtrA1 increased with increasing gestational age, whereas, in PE pregnancies HtrA1 levels remained stable, but were not significantly different from control pregnancies at any gestational age.

DISCUSSION

Serum HtrA1 levels are not significantly different in women who develop PE compared to controls.

Second- and third-trimester serum levels of growth-differentiation factor-15 in prediction of pre-eclampsia

OBJECTIVE

Pre-eclampsia (PE) is a significant contributor to adverse maternal and perinatal outcome; however, accurate prediction and early diagnosis of this condition remain a challenge. The aim of this study was to compare serum levels of growth-differentiation factor-15 (GDF-15) at three different gestational ages between asymptomatic women who subsequently developed preterm or term PE and healthy controls.

METHODS

This was a case-control study drawn from a prospective observational study on adverse pregnancy outcomes in women attending for their routine second- and third-trimester hospital visits. Serum GDF-15 was determined in 300 samples using a commercial GDF-15 enzyme-linked immunosorbent assay: 120 samples at 19-24 weeks of gestation, 120 samples at 30-34 weeks and 60 samples at 35-37 weeks. Multiple linear regression was applied to logarithmically transformed GDF-15 control values to evaluate the influence of gestational age at blood sampling and maternal characteristics on GDF-15 results. GDF-15 multiples of the normal median (MoM) values, adjusted for gestational age and maternal characteristics, were compared between pregnancies that subsequently developed preterm or term PE and healthy controls.

RESULTS

Values of GDF-15 increased with gestational age. There were no significant differences in GDF-15 MoM values between cases of preterm or term PE and normotensive pregnancies at 19-24 or 35-37 weeks of gestation. At 30-34 weeks, GDF-15 MoM values were significantly increased in cases of preterm PE, but not in those who later developed term PE. Elevated GDF-15 MoM values were associated significantly with a shorter interval between sampling at 30-34 weeks and delivery with PE (P = 0.005).

CONCLUSION

Serum GDF-15 levels at 19-24 or 35-37 weeks of gestation are not predictive of preterm or term PE. At 30-34 weeks, GDF-15 levels are higher in women who subsequently develop preterm PE; however, this difference is small and GDF-15 is unlikely to be useful in clinical practice when used in isolation. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Prevalence and risk factors of intrahepatic cholestasis of pregnancy in a Chinese population

Studies on the risk factors for intrahepatic cholestasis of pregnancy (ICP) in a population-based cohort are lacking. We assess the prevalence and risk factors of ICP in a Chinese population. In this study, a cohort study was conducted that included 12,200 eligible pregnant women. The overall incidence of ICP in this cohort was 6.06%. With increasing maternal age, the incidence of ICP decreased in women younger than 30 years of age but increased in those older than 30. With increasing pre-pregnancy BMI, the incidence of ICP decreased if the pre-pregnancy BMI was less than 23 kg/m² but increased if it was 23 kg/m² or higher. Further analysis showed that the risk of ICP increased when maternal age was < 25 years (Adjusted RR  2.01; 95% CI 1.64–2.47) or ≥ 35 years (Adjusted RR  1.34; 95% CI 1.02–1.76). Furthermore, an increased risk of ICP was associated with pre-pregnancy underweight (adjusted RR  1.27; 95% CI 1.04–1.56), inadequate gestational weight gain (GWG) (adjusted RR  1.58; 95% CI 1.28–1.96), lower maternal education (adjusted RR  2.96; 95% CI 2.35–3.74), multiparity (adjusted RR  1.54; 95% CI 1.23–1.93), and twin/multiple pregnancies (adjusted RR  2.12; 95% CI 1.25–3.58). Maternal age (< 25 or ≥ 35 years), underweight, inadequate GWG, lower maternal education, multiparity, and twin/multiple pregnancies were identified as risk factors of ICP.

Metabolic regulation of polyamines and γ-aminobutyric acid in relation to spermidine-induced heat tolerance in white clover

Heat stress decreases crop growth and yield worldwide. Spermidine (Spd) is a small aliphatic amine and acts as a ubiquitous regulator for plant growth, development and stress tolerance. Objectives of this study were to determine effects of exogenous Spd on changes in endogenous polyamine (PA) and γ-aminobutyric acid (GABA) metabolism, oxidative damage, senescence and heat shock protein (HSP) expression in white clover subjected to heat stress. Physiological and molecular methods, including colorimetric assay, high performance liquid chromatography and qRT-PCR, were applied. Results showed that exogenous Spd significantly alleviated heat-induced stress damage. Application of Spd not only increased endogenous putrescine, Spd, spermine and total PA accumulation, but also accelerated PA oxidation and improved glutamic acid decarboxylase activity, leading to GABA accumulation in leaves under heat stress. The Spd-pretreated white clover maintained a significantly higher chlorophyll (Chl) content than untreated plants under heat stress, which could be related to the roles of Spd in up-regulating genes encoding Chl synthesis (PBGD and Mg-CHT) and maintaining reduced Chl degradation (PaO and CHLASE) during heat stress. In addition, Spd up-regulated HSP70, HSP70B and HSP70-5 expression, which might function in stabilizing denatured proteins and helping proteins to folding correctly in white clover under high temperature stress. In summary, exogenous Spd treatment improves the heat tolerance of white clover by altering endogenous PA and GABA content and metabolism, enhancing the antioxidant system and HSP expression and slowing leaf senescence related to an increase in Chl biosynthesis and a decrease in Chl degradation during heat stress.

[Effects of Prrx2 gene silencing on the proliferation of breast cancer and its molecular mechanisms]

Objective: The aim of this study was to investigate the effects of silencing Paired related homoeobox 2 (Prrx2) expression on the proliferation of breast cancer and its molecular mechanisms. Methods: Short hairpin RNA knockdown of Prrx2 was used to examine cellular effects of Prrx2. The level of Prrx2 was verified by Western blot. MTT assay was used to analyze the proliferation of breast cancer cells in vitro. To investigate the effect of Prrx2 depletion on tumor growth in vivo, a nude mouse xenograft model was performed. Results: The expression of Prrx2 decreased 91.2% in MDA-MB-231 cells and 88.7% in MCF-7 cells after transfection with interfering vectors (P<0.05). MTT assay showed that the proliferation of cells in silenced Prrx2 expression group was significantly inhibited compared with the control group (P<0.05). Nude mice transplanted tumors showed that the growth of transplanted tumors was slow after silencing Prrx2 expression, and the weight of the tumors of silenced Prrx2 expression group were smaller than those of the control group ((160.2±26.3)mg vs (365.4±19.7)mg, P<0.05). Western blot showed that silencing Prrx2 expression inhibited the expression of β-catenin in breast cancer cell nucleus and down-regulated the activity of Wnt/β-catenin signaling pathway. Conclusions: Silencing Prrx2 expression can effectively inhibit the proliferation and growth of breast cancer, suggesting that Prrx2 may become a new target for the treatment of breast cancer.

Elevated circulating HtrA4 in preeclampsia may alter endothelial expression of senescence genes

INTRODUCTION

Preeclampsia (PE) is a serious complication of human pregnancy. Women who have had PE, especially early-onset PE (EPE), have an increased risk of cardiovascular disease (CVD) later in life. However, how PE is linked to CVD is not well understood. We previously reported that HtrA4, a placenta-specific protease, is significantly elevated in EPE, and inhibits the proliferation of endothelial cells as well as endothelial progenitor cells (EPCs). This can potentially impair endothelial repair and regeneration, leading to endothelial aging, which is a major risk factor of CVD. In this study, we examined whether HtrA4 can alter endothelial expression of senescence genes.

METHODS

Human umbilical vein endothelial cells (HUVECs) and primary EPCs isolated from cord blood of healthy pregnancies were used as in vitro models. Firstly, HUVECs were treated with HtrA4 at the highest levels detected in EPE for 48h and screened with a senescence PCR array. The results were then validated by RT-PCR and ELISA in HUVECs and EPCs treated with HtrA4 for 24 and 48h.

RESULTS

We observed that HtrA4 significantly up-regulated IGFBP3, SERPINE1 and SERPINB2, which all promote senescence. IGFBP-3 protein was also significantly elevated in the media of HtrA4-treated HUVECs. Conversely, a number of genes including CDKN2C, PCNA, CALR, CHEK2 and NOX4 were downregulated by HtrA4. Many of these genes also showed a similar trend of change in EPCs following HtrA4 treatment.

DISCUSSION

Elevation of placenta-derived HtrA4 in PE alters the expression of endothelial genes to promote cellular senescence and may contribute to premature endothelial aging.

Serum podocalyxin at 11-13 weeks of gestation in the prediction of small for gestational age neonates

OBJECTIVE

To investigate a potential new marker for the prediction of small for gestational age (SGA) infants.

STUDY DESIGN

Nested case-control study involving 280 uncomplicated pregnancies and 70 cases of SGA without pre-eclampsia. Serum podocalyxin was measured at 11-13 weeks of gestation and results were expressed in multiples of the median (MoM). The performance of screening by a combination of maternal history and podocalyxin levels was assessed with ROC curves.

RESULTS

SGA was predicted by maternal age, height, South Asian ethnicity, and previous delivery without pre-eclampsia. Median podocalyxin levels were higher in affected than uncomplicated pregnancies (1.303 versus 0.994 MoM, p < 0.001). At a 10% false-positive rate, maternal history identified 40.0% of the cases (AUC = 0.74, 95%CI 0.671-0.809). The addition of podocalyxin increased the detection to 54.3% (AUC = 0.78, 95%CI 0.771-0.842, p = 0.027 for the difference in ROC curves).

CONCLUSION

First-trimester podocalyxin may be useful in screening for SGA infants.

Low Serum Levels of HtrA3 at 15 Weeks of Gestation Are Associated with Late-Onset Preeclampsia Development and Small for Gestational Age Birth

OBJECTIVE

The aim of this study was to investigate the potential utility of serum HtrA1 and HtrA3, serine proteases that are highly expressed in the developing placenta, at 15 and 20 weeks of gestation for predicting later development of adverse pregnancy outcomes of preeclampsia (PE), gestational hypertension (GHT), preterm birth (PTB), and small for gestational age (SGA) birth.

METHODS

This is a nested case control study of 665 samples (330 controls, 335 cases) from the Adelaide SCOPE cohort. The cases included were 92 PE, 71 GHT, 56 PTB, and 116 SGA. Samples were assessed by ELISA and data adjusted for maternal age, BMI, socioeconomic index, hCG, and smoking status. Multivariate logistic regression was performed with other biochemical and biophysical parameters available for these samples.

RESULTS

HtrA1 did not differ between the controls and cases. In contrast, HtrA3 was significantly lower at 15 weeks in pregnancies that later developed late-onset PE (LPE) or resulted in SGA birth, with an area under the ROC curve (AUC) of 0.716 and 0.790, respectively. The combination of HtrA3 with PAPP-A, uterine, and umbilical Doppler improved the AUC to 0.755 for LPE and 0.844 for SGA.

CONCLUSION

HtrA3 at 15 weeks is associated with, and may be useful for, the early detection of LPE development and SGA birth.

MiRNA-106a promotes breast cancer progression by regulating DAX-1

OBJECTIVE

The aim of this study was to explore the expression of microRNA-106a in breast cancer (BC) and to further investigate its role in BC development and the potential regulatory mechanism.

PATIENTS AND METHODS

72 pairs of BC tissues and para-cancerous tissues were collected, and microRNA-106a expression was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between microRNA-106a expression and BC pathological parameters was analyzed. Meanwhile, the expression of microRNA-106a in BC cells was verified by qRT-PCR as well. In addition, microRNA-106a knockdown model was constructed by transfecting small interfering RNA in BC cell lines including MCF-7 and SKBR3. Subsequently, the effects of microRNA-106a on biological functions of BC cells were analyzed by cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EDU), and transwell invasion and migration assays, respectively. Finally, the underlying mechanism was explored by cellular rescue experiment.

RESULTS

QRT-PCR results illustrated that microRNA-106a expression in BC tissues was markedly higher than that of normal tissues. Patients with high expression of microRNA-106a exhibited significantly higher tumor stage as well as higher incidence of lymph node metastasis and distant metastasis when compared with those with low expression. Cell proliferation, invasion, and migration abilities in microRNA-106a inhibitor group were markedly decreased when compared with control group. Subsequent experiments demonstrated that DAX-1 expression was reduced in BC cell lines and tissues. Moreover, DAX-1 expression was negatively correlated with microRNA-106a expression. In addition, a recovery experiment found that microRNA-106a and DAX-1 had mutual regulation, which could affect the malignant progression of BC.

CONCLUSIONS

We found that the expression of microRNA-106a was significantly increased in BC. Meanwhile, microRNA-106a expression was closely related to BC stage, distant metastasis, lymph node metastasis, and poor prognosis. Therefore, microRNA-106a promoted the invasion, migration, and proliferation of BC by targeting DAX-1.

HtrA4 may play a major role in inhibiting endothelial repair in pregnancy complication preeclampsia

Preeclampsia (PE) is a life-threatening complication of human pregnancy with no effective treatment other than premature delivery. It is hallmarked by systemic endothelial injury/dysfunction which is believed to be caused by abnormal levels/types of placenta-derived factors that are circulating in the maternal blood. Emerging evidence suggests that endothelial repair is also dysregulated in PE, as circulating endothelial progenitor cells (EPCs) critical for endothelial regeneration are reduced in number and functionality. However, the underlying mechanisms are poorly understood. HtrA4 is a placenta-specific protease that is secreted into the circulation and significantly elevated in early-onset PE. Here we investigated the impact of HtrA4 on endothelial proliferation and repair. We demonstrated that high levels of HtrA4 halted endothelial cell proliferation and significantly down-regulated a number of genes that are critical for cell cycle progression, including CDKN3, BIRC5, CDK1 and MKI67. Furthermore, HtrA4 significantly inhibited the proliferation of primary EPCs isolated from term human umbilical cord blood and impeded their differentiation into mature endothelial cells. Our data thus suggests that elevated levels of HtrA4 in the early-onset PE circulation may impair endothelial cell repair, not only by halting endothelial cell proliferation, but also by inhibiting the proliferation and differentiation of circulating EPCs.