Human placental 3β-hydroxysteroid dehydrogenase/steroid Δ5,4-isomerase 1: Identity, regulation and environmental inhibitors

The metabolic activation of pentachlorophenol to chloranil as a potent inhibitor of human and rat placental 3β-hydroxysteroid dehydrogenases

Pentachlorophenol (PCP) is a widely used pesticide. However, whether PCP and its metabolite chloranil have endocrine-disrupting effects by inhibiting placental 3β-hydroxysteroid dehydrogenase 1 (3β-HSD1) remains unclear. The study used in vitro assays with human and rat placental microsomes to measure 3β-HSD activity as well as human JAr cells to evaluate progesterone production. The results showed that PCP exhibited moderate inhibition of human 3β-HSD1, with an IC50 value of 29.83 μM and displayed mixed inhibition in terms of mode of action. Conversely, chloranil proved to be a potent inhibitor, demonstrating an IC50 value of 147 nM, and displaying a mixed mode of action. PCP significantly decreased progesterone production by JAr cells at 50 μM, while chloranil markedly reduced progesterone production at ≥1 μM. Interestingly, PCP and chloranil moderately inhibited rat placental homolog 3β-HSD4, with IC50 values of 27.94 and 23.42 μM, respectively. Dithiothreitol (DTT) alone significantly increased human 3β-HSD1 activity. Chloranil not PCP mediated inhibition of human 3β-HSD1 activity was completely reversed by DTT and that of rat 3β-HSD4 was partially reversed by DTT. Docking analysis revealed that both PCP and chloranil can bind to the catalytic domain of 3β-HSDs. The difference in the amino acid residue Cys83 in human 3β-HSD1 may explain why chloranil is a potent inhibitor through its interaction with the cysteine residue of human 3β-HSD1. In conclusion, PCP is metabolically activated to chloranil as a potent inhibitor of human 3β-HSD1.

A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical exposures during pregnancy include several developmental and reproductive disorders. However, considering the tens of thousands of chemicals present on the market, the effects of chemical mixtures on the developing fetus is still likely underestimated. In this critical review, we discuss the potential to apply innovative biomonitoring methods using high-resolution mass spectrometry (HRMS) on placenta to improve the monitoring of chemical exposure during pregnancy. The physiology of the placenta and its relevance as a matrix for monitoring chemical exposures and their effects on fetal health is first outlined. We then identify several key parameters that require further investigations before placenta can be used for large-scale monitoring in a robust manner. Most critical is the need for standardization of placental sampling. Placenta is a highly heterogeneous organ, and knowledge of the intraplacenta variability of chemical composition is required to ensure unbiased and robust interindividual comparisons. Other important variables include the time of collection, the sex of the fetus, and mode of delivery. Finally, we discuss the first applications of HRMS methods on the placenta to decipher the chemical exposome and describe how the use of placenta can complement biofluids collected on the mother or the fetus.

Probiotic and prebiotic supplementation ameliorates chronic restraint stress-induced male reproductive dysfunction

Restraint stress (RS) can induce male reproductive deficits by activating the hypothalamic-pituitary-adrenal (HPA) axis and causing oxidative stress. Previous studies have shown that probiotics can alleviate neurological and metabolic disorders induced by stress. However, the effects of probiotics on RS-induced reproductive deficits have not been fully elucidated. This study aimed to investigate whether Lactobacillus rhamnosus NCDC-610 (Probiotic-1) and Lactobacillus fermentum NCDC-400 (Probiotic-2) with prebiotic (fructooligosaccharides (FOS)) could prevent RS-induced reproductive deficits. C57BL6/J mice were subjected to RS for four hours daily before oral administration of probiotics (4 × 109 CFU per mice) either separately or concurrently with FOS. The results showed that oral administration of Probiotic-1 and Probiotic-2 protected against RS-induced sperm deficits, including sperm count, motility, morphology, and histopathology of testes, and improved intestinal health. Furthermore, Probiotic-1 and Probiotic-2 prevented RS-induced changes in testosterone levels by up-regulating the expressions of steroidogenic acute regulatory protein (StAR), cytochrome P450 side-chain cleavage enzyme (P450scc), and 17β-hydroxysteroid dehydrogenase (17βHSD) in the testes. Additionally, Probiotic-1 and Probiotic-2 increased the activities of catalase and superoxide dismutase and reduced the fold change of interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-α), indicating a protective effect against RS-induced oxidative stress. Oral administration of Probiotic-1 and Probiotic-2, either separately or concurrently with FOS (probiotic dose of 4 × 109 CFU per mice and prebiotic 5% w/v), prevented RS-induced activation of the HPA axis and improved male fertility. These findings suggest that L. rhamnosus NCDC-610 and L. fermentum NCDC-400 are safe and effective probiotics for mitigating stress-induced male reproductive deficits.

3βHSD activity saturates at physiological substrate concentrations in intact cells

BACKGROUND

Conversion of adrenally produced dehydroepiandrosterone (DHEA) to the potent androgen dihydrotestosterone (DHT) is an important mechanism by which prostate cancer reaches castration resistance. At the start of this pathway is a branch point at which DHEA can be converted to Δ4 -androstenedione by the enzyme 3β-hydroxysteroid dehydrogenase (3βHSD) or to Δ5 -androstenediol by 17βHSD. To better understand this process, we studied the kinetics of these reactions in cells.

METHODS

Prostate cancer cells (LNCaP cell line) were incubated with steroids (DHEA and Δ5 -androstenediol) over a range of concentrations and the steroid metabolism reaction products were measured by mass spectrometry or by high-performance liquid chromatography to determine reaction kinetics. To confirm the generalizability of results, experiments were also performed in JEG-3 placental choriocarcinoma cells.

RESULTS

The two reactions displayed very different saturation profiles, with only the 3βHSD-catalyzed reaction beginning to saturate within a physiological substrate concentration range. Strikingly, incubating LNCaP cells with low (in the ~10 nM range) concentrations of DHEA resulted in a large majority of the DHEA undergoing 3βHSD-catalyzed conversion to Δ4 -androstenedione, whereas high concentrations of DHEA (in the 100s of nM range) resulted in most of the DHEA undergoing 17βHSD-catalyzed conversion to Δ5 -androstenediol.

CONCLUSION

Contrary to expectations from previous studies that used purified enzyme, cellular metabolism of DHEA by 3βHSD begins to saturate in the physiological concentration range, suggesting that fluctuations in DHEA concentrations could be buffered at the downstream active androgen level.

Development of a human iPSC-derived placental barrier-on-chip model

Although recently developed placenta-on-chip systems opened promising perspectives for placental barrier modeling, they still lack physiologically relevant trophoblasts and are poorly amenable to high-throughput studies. We aimed to implement human-induced pluripotent stem cells (hiPSC)-derived trophoblasts into a multi-well microfluidic device to develop a physiologically relevant and scalable placental barrier model. When cultured in a perfused micro-channel against a collagen-based matrix, hiPSC-derived trophoblasts self-arranged into a 3D structure showing invasive behavior, fusogenic and endocrine activities, structural integrity, and expressing placental transporters. RNA-seq analysis revealed that the microfluidic 3D environment boosted expression of genes related to early placental structural development, mainly involved in mechanosensing and cell surface receptor signaling. These results demonstrated the feasibility of generating a differentiated primitive syncytium from hiPSC in a microfluidic platform. Besides expanding hiPSC-derived trophoblast scope of applications, this study constitutes an important resource to improve placental barrier models and boost research and therapeutics evaluation in pregnancy.

Inhibition of Resveratrol Analogs on Human and Rat 3β-Hydroxysteroid Dehydrogenases: Structure-Activity Relationship and Docking Analysis

Resveratrol and its analogs are phytochemicals. Human 3β-hydroxysteroid dehydrogenase 1 (3β-HSD1) synthesizes steroid hormones for normal pregnancy or promoting cancer metastasis. Whether they inhibit 3β-HSD1 remains unclear. In this study, the inhibitory potency, mode of action, structure-activity relationship, and docking parameters of resveratrol and its analogs on 3β-HSD1 and rat homolog 3β-HSD4 were analyzed. The inhibitory potency of these chemicals on human 3β-HSD1 was 4,4'-dihydroxystilbene (IC₅₀, 3.68 μM) > pinostilbene (8.07 μM) > pinosylvin (10.60 μM) > lunularin (26.84 μM) > resveratrol (30.20 μM) > dihydroresveratrol (>100 μM) = oxyresveratrol (>100 μM) > dihydropinosylvin (ineffective at 100 μM). Resveratrol analogs and metabolites are mixed or competitive inhibitors of human 3β-HSD1. Resveratrol and 4,4'-dihydroxystilbene inhibited progesterone secretion by human JAr cells at ≥1 μM. Resveratrol (IC₅₀, 32.09 μM) and pinosylvin (34.71 μM) significantly inhibited rat placental 3β-HSD4 activity. Docking analysis shows that resveratrol analogs and metabolites bind the steroid-binding sites of human 3β-HSD1 and rat 3β-HSD4 and interact with the catalytic residues Ser125/Thr125 and Tyr155. The negative correlation of LogP and IC₅₀ values for human 3β-HSD1 indicates that lipophilicity of chemicals plays a critical role in the inhibitory effect of chemicals. In conclusion, 4,4'-dihydroxystilbene, pinostilbene, and pinosylvin effectively inhibit human 3β-HSD1 depending on their lipophilicity, thereby acting as potential therapeutic agents.

The analysis of pesticides and fungicides in the inhibition of human and rat placental 3β-hydroxysteroid dehydrogenase activity: mode of inhibition and mechanism

3β-Hydroxysteroid dehydrogenase/steroid Δ^5,4-isomerase 1 (3β-HSD1) plays a critical role in the biosynthesis of progesterone from pregnenolone in the human placenta to maintain normal pregnancy. Whether they inhibit placental 3β-HSD1 and mode of inhibition remains unclear. In this study, we screened 21 pesticides and fungicides in five classes to inhibit human 3β-HSD1 and compared them to rat homolog 3β-HSD4. 3β-HSD activity was measured by catalyzing pregnenolone to progesterone in the presence of NAD⁺. Of the 21 chemicals, azoles (difenoconazole), thiocarbamates (thiram and ferbam) and organochlorine (hexachlorophene) significantly inhibited human 3β-HSD1 with half maximal inhibitory concentration (IC₅₀) values of 2.77, 0.24, 0.68, and 17.96 μM, respectively. We also found that difenoconazole, ferbam and hexachlorophene are mixed/competitive inhibitors of 3β-HSD1 while thiram is a mixed/noncompetitive inhibitor. Docking analysis showed that difenoconazole and hexachlorophene bound steroid-binding site. Difenoconazole and hexachlorophene except thiram and ferbam also significantly inhibited rat 3β-HSD4 activity with IC₅₀ of 1.12 and 2.28µM, respectively. Thiram and ferbam significantly inhibited human 3β-HSD1 possibly by interfering with cysteine residues, while they had no effects on rat 3β-HSD4. In conclusion, some pesticides potently inhibit placental 3β-HSD, leading to the reduction of progesterone formation.

Long-read sequencing reveals the effect of follicle-stimulating hormone on the mRNA profile of chicken granulosa cells from prehierarchical follicles

Follicle selection is an important step in the laying process of chicken, which is closely related to the laying performance and fecundity of hens. Follicle selection mainly depends on the regulation of follicle-stimulating hormone (FSH) secreted by pituitary gland and the expression of follicle stimulation hormone receptor. To uncover the role of FSH in chicken follicle selection, in this study, we analyzed the changes in the mRNA transcriptome profiles of FSH-treated chicken granulosa cells from prehierarchical follicles by long-read sequencing Oxford Nanopore Technologies (ONT) approach. Among the 10,764 genes detected, 31 differentially expressed (DE) transcripts of 28 DE genes were significantly upregulated by FSH treatment. These DE transcripts (DETs) were mainly related to the steroid biosynthetic process by GO analysis and enriched in pathways of ovarian steroidogenesis and aldosterone synthesis and secretion by KEGG analysis. Among these genes, the mRNA and protein expression of TNF receptor associated factor 7 (TRAF7) was upregulated after FSH treatment. Further study revealed that TRAF7 stimulated the mRNA expression of steroidogenic enzymes steroidogenic acute regulatory protein (StAR) and cytochrome P450 family 11 subfamily A member 1 (CYP11A1) genes and the proliferation of granulosa cells. This is the first study to investigate differences in chicken prehierarchical follicular granulosa cells before and after FSH treatment by using ONT transcriptome sequencing, which provides a reference for a more comprehensive understanding of the molecular mechanism of follicle selection in chicken.

Inhibition of human and rat placental 3β-hydroxysteroid dehydrogenase/Δ5,4-isomerase activities by insecticides and fungicides: Mode action by docking analysis

Many insecticides and fungicides are endocrine-disrupting compounds, which possibly interfere with the placental endocrine system. In the placenta, 3β-hydroxysteroid dehydrogenase/Δ^5,4-isomerase type 1 (HSD3B1) is the major steroidogenic enzyme, which makes progesterone from pregnenolone to support the placental stability. In this study, we screened 12 classes of insecticides and fungicides to inhibit placental HSD3B1 activity and compared them to the rat homolog type 4 (HSD3B4) isoform. Human HSD3B1 activity and rat HSD3B4 activity were measured in the presence of 200 nM pregnenolone and 0.2 mM NAD⁺ and 100 μM of test chemical. Triclosan, triflumizole, dichlone, and oxine at 100 μM significantly inhibited human HSD3B1 activity with the residual activity being less than 50% of the control. Further study showed that the half-maximal inhibitory concentration (IC₅₀) values of triclosan, triflumizole, dichlone, and oxine were 85.53 ± 9.14, 73.75 ± 3.42, 2.54 ± 0.40, and 102.93 ± 6.10 μM, respectively. In the presence of pregnenolone, triclosan, triflumizole, and dichlone were mixed inhibitors of HSD3B1, while oxine was a noncompetitive inhibitor. In the presence of NAD⁺, triclosan exhibited competitive inhibition while triflumizole possessed uncompetitive inhibition. Docking analysis showed that triclosan bound NAD⁺-binding site, while triflumizole, dichlone, and oxine mostly bound steroid-binding site. When the effect of these insecticides on rat placental HSD3B4 activity was screened in the presence of 200 nM pregnenolone, atrazine, triclosan, triflumizole, oxine, cyprodinil, and diphenyltin at 100 μM significantly inhibited rat HSD3B4 activity, with IC₅₀ values of triclosan, triflumizole, oxine, and cyprodinil were 82.99 ± 6.48, 35.45 ± 2.73, 105.59 ± 12.04, and 43.37 ± 3.00 μM, respectively. The mode action analysis showed that triflumizole and cyprodinil were almost competitive inhibitors, while triclosan and oxine were almost noncompetitive inhibitors of rat HSD3B4. Docking analysis showed that triclosan and oxine bound cofactor NAD⁺ binding residues more than steroid-binding residues of rat HSD3B4 while triflumizole and cyprodinil bound most pregnenolone-interactive residues. In conclusion, some insecticides such as triclosan, triflumizole, and oxine can effectively inhibit both human and rat placental HSD3B activity and they have unique mode action due to the structure difference.

Structure-activity relationship analysis of perfluoroalkyl carbonic acids on human and rat placental 3β-hydroxysteroid dehydrogenase activity

Placenta contains 3β-hydroxysteroid dehydrogenase/steroid Δ^5,4-isomerase (HSD3B), which catalyzes pregnenolone to progesterone for maintaining pregnancy. Perfluoroalkyl carbonic acids (PFC) are subclass of perfluoroalkyl substances containing 4-14 carbons (C4-C14) in the carbon backbone and are potential endocrine disruptors. Whether PFC inhibit HSD3B and structure-activity relationship (SAR) remains unclear. Herein, we screened 11 PFC for inhibiting human type I HSD3B (HSD3B1) and rat type IV HSD3B (HSD3B4) activities and determined SAR and mode of inhibition. HSD3B was measured by converting pregnenolone to progesterone assisted by NAD⁺ in placental microsomes. Of the 11 PFC, C9-C14 significantly inhibited human HSD3B1 activity at 100 μM. Half-maximal inhibitory concentration (IC₅₀) values of C9-C14 compounds were 363.56 ± 12.14, 12.78 ± 0.69, 6.54 ± 0.65, 20.88 ± 0.41, 118.35 ± 0.16, and 149.26 ± 21.67 μM, respectively. We determined Ki values and mode of inhibition of three most potent PFC (C10-C12), and found that they were mixed inhibitors against pregnenolone, with Ki values of 5.57 ± 4.37, 2.04 ± 2.26, and 9.93 ± 7.71, respectively. Docking analysis showed that they bound steroid-binding site. Effects of PFC on rat placental HSD3B4 were performed. Of the 11 PFC, C10-C12 significantly inhibited rat HSD3B4 activity at 100 μM. IC₅₀ values of C10-C12 compounds were 45.85 ± 1.49, 36.08 ± 1.50, and 88.74 ± 1.99 µM, respectively. Ki values and inhibition modes of the three most potent PFC (C10-C12) were studied. It was found that they were mixed inhibitors against pregnenolone, with Ki values of 48.16 ± 20.44, 36.28 ± 53.07, and 91.79 ± 21.75 μM, respectively. Docking analysis showed that they bound steroid-binding site of rat HSD3B4. In conclusion, PFC showed significant SAR differences. The potency of inhibiting HSD3B activity increased from C9 to C11, and then declined. Human HSD3B1 was more sensitive to the inhibition of rat HSD3B4.

Uptake, Transport, and Toxicity of Pristine and Weathered Micro- and Nanoplastics in Human Placenta Cells

BACKGROUND

The first evidence of micro- and nanoplastic (MNP) exposure in the human placenta is emerging. However, the toxicokinetics and toxicity of MNPs in the placenta, specifically environmentally relevant particles, remain unclear.

OBJECTIVES

We examined the transport, uptake, and toxicity of pristine and experimentally weathered MNPs in nonsyncytialized and syncytialized BeWo b30 choriocarcinoma cells.

METHODS

We performed untargeted chemical characterization of pristine and weathered MNPs using liquid chromatography high-resolution mass spectrometry to evaluate compositional differences following particle weathering. We investigated cellular internalization of pristine and weathered polystyrene (PS; 0.05-10μm) and high-density polyethylene (HDPE; 0-80μm) particles using high-resolution confocal imaging and three-dimensional rendering. We investigated the influence of particle coating with human plasma on the cellular transport of PS particles using a transwell setup and examined the influence of acute MNP exposure on cell viability, damage to the plasma membrane, and expression of genes involved in steroidogenesis.

RESULTS

Chemical characterization of MNPs showed a significantly higher number of unique features in pristine particles in comparison with weathered particles. Size-dependent placental uptake of pristine and weathered MNPs was observed in both placental cell types after 24 h exposure. Cellular transport was limited and size-dependent and was not influenced by particle coating with human plasma. None of the MNPs affected cell viability. Damage to the plasma membrane was observed only for 0.05μm PS particles in the nonsyncytialized cells at the highest concentration tested (100μg/mL). Modest down-regulation of hsd17b1 was observed in syncytialized cells exposed to pristine MNPs.

DISCUSSION

Our results suggest that pristine and weathered MNPs are internalized and translocated in placental cells in vitro. Effects on gene expression observed upon pristine PS and HDPE particle exposure warrant further examination. More in-depth investigations are needed to better understand the potential health risks of MNP and chemicals associated with them under environmentally relevant exposure scenarios. https://doi.org/10.1289/EHP10873.

Natural disaster stress during pregnancy is linked to reprogramming of the placenta transcriptome in relation to anxiety and stress hormones in young offspring

Prenatal stress can lead to long-term adverse effects that increase the risk of anxiety and other emotional disorders in offspring. The in utero underpinnings contributing to such phenotypes remain unknown. We profiled the transcriptome of placental specimens from women who lived through Hurricane Sandy during pregnancy compared to those pregnant during non-Sandy conditions. Following birth, longitudinal assessments were conducted in their offspring during childhood (~3-4 years old) to measure steroid hormones (in hair) and behavioral and emotional problems. This revealed a significant link between prenatal Sandy stress (PNSS) and child HPA dysfunction, evident by altered cortisol, dehydroepiandrosterone (DHEA), and cortisol:DHEA levels. In addition, PNSS was associated with significantly increased anxiety and aggression. These findings coincided with significant reorganization of the placental transcriptome via vascular, immune, and endocrine gene pathways. Interestingly, many of the most prominently altered genes were known to be uniquely expressed in syncytiotrophoblast (STB)-subtype of placental cells and harbored glucocorticoid response elements in promoter regions. Finally, several vascular development- and immune-related placental gene sets were found to mediate the relationship between PNSS and childhood phenotypes. Overall, these findings suggest that natural disaster-related stress during pregnancy reprograms the placental molecular signature, potentially driving long-lasting changes in stress regulation and emotional health. Further examination of placental mechanisms may elucidate the environment's contribution to subsequent risk for anxiety disorders later in life.

miR-27b-5p inhibits BeWo cells fusion by regulating WNT2B and enzyme involved in progesterone synthesis

PROBLEM

The miRNAs show placenta-specific expression patterns, which alter during pregnancy-related complications. In present study, the role of miR-27b-5p during forskolin-mediated BeWo cells fusion has been investigated.

METHOD OF STUDY

The fusion of BeWo cells in response to forskolin treatment (25 µM) was studied by desmoplakin I+II staining. Expression profile of miR-27b-5p by qRT-PCR and its targets HSD3β1 and WNT2B by qRT-PCR and in Western blot were studied. The effect of overexpression of miR-27b-5p and silencing of HSD3β1 & WNT2B by siRNA on forskolin-mediated BeWo cells fusion and secretion of hCG and progesterone by ELISA was investigated.

RESULTS

Time-dependent down-regulation in the expression of miR-27b-5p in forskolin-treated BeWo cells has been confirmed by qRT-PCR. Overexpression of miR-27b-5p significantly inhibits forskolin-mediated BeWo cells fusion as well as hCG & progesterone secretion. HSD3β1 and WNT2B were identified as targets of miR-27b-5p and are up-regulated in forskolin-treated BeWo cells. Overexpression of miR-27b-5p in BeWo cells downregulates their expression. Further, luciferase reporter assay revealed that miR-27b-5p directly target expression of both HSD3β1 and WNT2B. Silencing of both HSD3β1 and WNT2B leads to a significant reduction in forskolin-mediated BeWo cells fusion with concomitant decrease in the secretion of progesterone or/and hCG. Decrease in forskolin-mediated cells fusion observed in miR-27b-5p mimic transfected BeWo cells could be rescued by the overexpression of both HSD3β1 and WNT2B.

CONCLUSION

These observations suggest that reduced miR-27b-5p in forskolin-treated BeWo cells leads to increased secretion of progesterone and hCG due to loss of repressional control on HSD3β1 and WNT2B.

Effects of dibenzothiophene, a sulfur-containing heterocyclic aromatic hydrocarbon, and its alkylated congener, 2,4,7-trimethyldibenzothiophene, on placental trophoblast cell function

Worldwide demand for petroleum products has resulted in increased oil and gas activities in many countries. Conventional and unconventional oil and gas extraction, production, and transport lead to increased levels of petroleum-derived polycyclic aromatic hydrocarbons (PAHs) in the environment. PAH exposure has profound effects on reproduction by affecting pathways involved in placental trophoblast cell function and impairing normal placental development and function-key contributors to reproductive success. However, other components found in petroleum and wastewaters from oil and gas extraction, including the sulfur-containing heterocyclic aromatic compounds such as dibenzothiophene (DBT) and its alkylated derivatives, may also impact reproductive success. The goal of this study was to examine the effect of exposure to DBT, a compound commonly detected in the environment, and one of its alkylated analogues, 2,4,7-trimethyldibenzothiophene (2,4,7-DBT), on steroidogenic and angiogenic pathways critical for mammalian development in placental trophoblast cells (HTR-8/SVneo cells). 2,4,7-DBT but not DBT increased estradiol output in association with increased tube-like formation (surrogate for angiogenesis). These changes in angiogenesis did not appear to be related to altered expression of the key placental angiogenic gene targets (ANGPTL4, VEGFA, and PGF). Neither compound showed a concentration related effect on progesterone synthesis or its receptor expression. Our results suggest that 2,4,7-DBT can disrupt key pathways important for placental trophoblast function and highlight the importance of determining the impact of exposure to both parent and alkylated compounds. Further, these data suggest that exposure to sulfur-containing heterocyclic aromatic compounds may lead to placental dysfunction and impact reproductive success at environmentally relevant levels.