The role of sulfated steroid hormones in reproductive processes

Cytosolic sulfotransferases in endocrine disruption

The mammalian cytosolic sulfotransferases (SULTs) catalyze the sulfation of endocrine hormones as well as a broad array of drugs, environmental chemicals, and other xenobiotics. Many endocrine-disrupting chemicals (EDCs) interact with these SULTs as substrates and inhibitors, and thereby alter sulfation reactions responsible for metabolism and regulation of endocrine hormones such as estrogens and thyroid hormones. EDCs or their metabolites may also regulate expression of SULTs through direct interaction with nuclear receptors and other transcription factors. Moreover, some sulfate esters derived from EDCs (EDC-sulfates) may serve as ligands for endocrine hormone receptors. While the sulfation of an EDC can lead to its excretion in the urine or bile, it may also result in retention of the EDC-sulfate through its reversible binding to serum proteins and thereby enable transport to other tissues for intracellular hydrolysis and subsequent endocrine disruption. This mini-review outlines the potential roles of SULTs and sulfation in the effects of EDCs and our evolving understanding of these processes.

Steroid sulfatase and sulfotransferases in the estrogen and androgen action of gynecological cancers: current status and perspectives

Sulfatase (STS) and sulfotransferases (SULT) have important role in the biosynthesis and action of steroid hormones. STS catalyzes the hydrolysis of estrone-sulfate (E1-S) and dehydroepiandrosterone-sulfate (DHEA-S), while sulfotransferases catalyze the reverse reaction and require 3-phosphoadenosine-5-phosphosulfate as a sulfate donor. These enzymes control the concentration of active estrogens and androgens in peripheral tissues. Aberant expression of STS and SULT genes has been found in both, benign hormone-dependent diseases and hormone-dependent cancers. The aim of this review is to present the current knowledge on the role of STS and SULT in gynecological cancers, endometrial (EC) and ovarian cancer (OC). EC is the most common and OC the most lethal gynecological cancer. These cancers primarily affect postmenopausal women and therefore rely on the local production of steroid hormones from inactive precursors, either DHEA-S or E1-S. Following cellular uptake by organic anion transporting polypeptides (OATP) or organic anion transporters (OAT), STS and SULT regulate the formation of active estrogens and androgens, thus disturbed balance between STS and SULT can contribute to the onset and progression of cancer. The importance of these enzymes in peripheral estrogen biosynthesis has long been recognized, and this review provides new data on the important role of STS and SULT in the formation and action of androgens, their regulation and inhibition, and their potential as prognostic biomarkers.

Structure-Activity Relationships and Target Selectivity of Phenylsulfonylamino-Benzanilide Inhibitors Based on S1647 at the SLC10 Carriers ASBT, NTCP, and SOAT

The intestinal bile acid carrier ASBT (SLC10A2), the hepatic bile acid carrier NTCP (SLC10A1), and the steroid sulfate carrier SOAT (SLC10A6), all members of the solute carrier family SLC10, are established drug targets. The ASBT inhibitors odevixibat, maralixibat, and elobixibat are used to treat intrahepatic cholestasis, cholestatic pruritus, and obstipation. The peptide drug bulevirtide blocks binding of the hepatitis B and D viruses to NTCP and thereby inhibits the virus's entry into hepatocytes. Experimental SOAT inhibitors have antiproliferative effects on hormone-dependent breast cancer cells. The phenylsulfonylamino-benzanilide S1647 is an inhibitor of ASBT and SOAT. The present study aimed to comparatively analyze a set of newly synthesized and commercially available S1647 derivatives for their transport inhibition against ASBT, NTCP, and SOAT. Structure-activity relationships were systematically analyzed regarding potency and target specificity to elucidate whether this compound class is worth being further developed in preclinical studies for pharmacological ASBT, NTCP, and/or SOAT inhibition.

Can longer lifespan be associated with gut microbiota involvement in lipid metabolism?

Biological aging is linked to altered body composition and reduced neuroactive steroid hormones like dehydroepiandrosterone sulfate (DHEAS), which can stimulate the GABA signaling pathway via gut microbiota. Our study examined the association of gut microbiota with lifespan in mice through comprehensive analysis of its composition and functional involvement in cholesterol sulfate, a precursor of DHEAS, metabolism. We used 16S rRNA and metagenomic sequencing, followed by metabolic pathway prediction and thin layer chromatography and MALDI-TOF cholesterol sulfate identification. Significant increases in bacteria such as Bacteroides, typical for long-lived and Odoribacter and Colidextribacter, specific for short-lived mice were detected. Furthermore, for males (Rikenella and Alloprevotella) and females (Lactobacillus and Bacteroides), specific bacterial groups emerged as predictors (AUC = 1), highlighting sex-specific patterns. Long-lived mice showed a strong correlation of Bacteroides (0.918) with lipid and steroid hormone metabolism, while a negative correlation of GABAergic synapse with body weight (-0.589). We found that several Bacteroides species harboring the sulfotransferase gene and gene cluster for sulfonate donor synthesis are involved in converting cholesterol to cholesterol sulfate, significantly higher in the feces of long-lived individuals. Overall, we suggest that increased involvement of gut bacteria, mainly Bacteroides spp., in cholesterol sulfate synthesis could ameliorate aging through lipid metabolism.

Steroid sulfatase in mouse liver and testis: Characterization, ontogeny and localization

Steroid hormones often circulate in the plasma as inactive sulfated forms, such as estrone sulfate and dehydroepiandrosterone sulfate. The enzyme steroid sulfatase (STS) converts these steroids into active forms, mainly estrogens, in peripheral tissues. STS is present in most tissues, but it occurs at higher levels in certain organs, notably liver and placenta. In this study, we examined the tissue distribution of STS in a prominent laboratory model, the house mouse (Mus musculus). Tissues included were heart, liver, small intestine, skeletal muscle, and gonads of both sexes. An 3H-estrone-sulfate conversion assay was used to measure STS activity in tissue homogenates and extracts. STS activities were high for hepatic tissue homogenates of both genders. Testicular STS levels were similar to those of liver, while STS activities of ovary, small intestine, heart, and muscle were considerably lower. The specific STS inhibitors, EMATE and STX-64 virtually eliminated STS activity in hepatic microsomes and cytosols, verifying that the observed enzyme activity was due to STS. Enzyme kinetic assays showed Km values of 8.6 µM for liver and 9.1 µM for testis, using E1S as substrate. Hepatic and testicular STS activities, measured in CHAPS-extracted microsome, were low up to 5 weeks of age and were higher through 56 weeks. Western blotting, with a specific STS antibody, confirmed the presence of STS protein (65 Da) in both liver and testis. Immunofluorescence of tissue sections detected the presence of STS protein in hepatocytes, in testicular Leydig cells and in seminiferous tubules (Leydig cells and developing germ cells). These results suggest that STS may have a significant role in testicular function.

Evolutionary analysis of SLC10 family members and insights into function and expression regulation of lamprey NTCP

The Na ( +)-taurocholate cotransporting polypeptide (NTCP) is a member of the solute carrier family 10 (SLC10), which consists of 7 members (SLC10a1-SLC10a7). NTCP is a transporter localized to the basolateral membrane of hepatocytes and is primarily responsible for the absorption of bile acids. Although mammalian NTCP has been extensively studied, little is known about the lamprey NTCP (L-NTCP). Here we show that L-NTCP follows the biological evolutionary history of vertebrates, with conserved domain, motif, and similar tertiary structure to higher vertebrates. L-NTCP is localized to the cell surface of lamprey primary hepatocytes by immunofluorescence analysis. HepG2 cells overexpressing L-NTCP also showed the distribution of L-NTCP on the cell surface. The expression profile of L-NTCP showed that the expression of NTCP is highest in lamprey liver tissue. L-NTCP also has the ability to transport bile acids, consistent with its higher vertebrate orthologs. Finally, using a farnesoid X receptor (FXR) antagonist, RT-qPCR and flow cytometry results showed that L-NTCP is negatively regulated by the nuclear receptor FXR. This study is important for understanding the adaptive mechanisms of bile acid metabolism after lamprey biliary atresia based on understanding the origin, evolution, expression profile, biological function, and expression regulation of L-NTCP.

Complex roles for sulfation in the toxicities of polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are persistent organic toxicants derived from legacy pollution sources and their formation as inadvertent byproducts of some current manufacturing processes. Metabolism of PCBs is often a critical component in their toxicity, and relevant metabolic pathways usually include their initial oxidation to form hydroxylated polychlorinated biphenyls (OH-PCBs). Subsequent sulfation of OH-PCBs was originally thought to be primarily a means of detoxication; however, there is strong evidence that it may also contribute to toxicities associated with PCBs and OH-PCBs. These contributions include either the direct interaction of PCB sulfates with receptors or their serving as a localized precursor for OH-PCBs. The formation of PCB sulfates is catalyzed by cytosolic sulfotransferases, and, when transported into the serum, these metabolites may be retained, taken up by other tissues, and subjected to hydrolysis catalyzed by intracellular sulfatase(s) to regenerate OH-PCBs. Dynamic cycling between PCB sulfates and OH-PCBs may lead to further metabolic activation of the resulting OH-PCBs. Ultimate toxic endpoints of such processes may include endocrine disruption, neurotoxicities, and many others that are associated with exposures to PCBs and OH-PCBs. This review highlights the current understanding of the complex roles that PCB sulfates can have in the toxicities of PCBs and OH-PCBs and research on the varied mechanisms that control these roles.

Comparative transcriptomic analysis of the different developmental stages of ovary in the cuttlefish Sepia pharaonis

The cuttlefish, Sepia pharaonis, is characterized by rapid growth and strong disease resistance, making it an important commercially farmed cephalopod species in the southeastern coastal regions of China. However, in the reproductive process of S. pharaonis, there are challenges such as a low output of eggs, poor quality, and low survival rates of newly hatched juveniles. Therefore, there is an urgent need to study the molecular mechanisms underlying ovarian development in this species. In this study, we conducted the first transcriptomic analysis of the ovary at four developmental stages: the undeveloped stage, developing stage, nearly-ripe stage, and ripe stage, and compared the transcriptomics among these four stages using Illumina sequencing technology. The total numbers of clean reads of the four stages ranged from 40,890,772 to 52,055,714 reads. A total of 136,829 DEGs were obtained, GC base ratios of raw data were between 38.44 and 44.59%, and the number of uniquely mapped reads spanned from 88.08 to 95.90%. The Pearson correlation coefficient demonstrated a strong correlation among different samples within the same group, PCA and Anosim analysis also revealed that the grouping of these four stages was feasible, and each stage could be distinguished from the others. GO enrichment analysis demonstrated that ovarian follicle growth, sex differentiation, and transforming growth factor beta receptor, played a foreshadowing role at the early ovarian development stage, and the terms of small molecule metabolic process, peptide metabolic process, and catalytic activity were prominent at the mature stage. Meanwhile, KEGG analysis showed that the early ovarian development of S. pharaonis was mainly associated with the cell cycle, DNA replication, and carbon metabolism, while the mid-late ovarian development was involved with the signal transduction, endocrine system, and reproduction pathway. RT-qPCR further confirmed the consistent expression patterns of genes such as 17β-HSD, GH, VGS, NFR, and NYR in the ovaries of S. pharaonis, exhibiting elevated levels of expression during the maturation stage. Conversely, ER and OM exhibited high expression levels during the early stages of ovarian development. These transcriptomic data provide insights into the molecular mechanisms of S. pharaonis ovarian development. The findings of this study will contribute to improving the reproduction and development of cuttlefish and enriching the bioinformatics knowledge of cephalopods.

Steroid Conjugates and Their Physiological Role

While there are hundreds of synthetic steroids conjugates with acids, sugars, proteins and other molecules, only two types of conjugates occur in living organisms, namely sulfates and glucuronides. Steroid glucuronidation in the human liver is the main mechanism controlling the levels and biological activity of unconjugated hormones, and glucuronides are their main excretion products. This process is generally irreversible. On the other hand, sulfates possess their own biological activity that differs from that of the unconjugated steroid, emphasizing the importance of steroid sulfatases and sulfotransferases. Due to their negative charge, steroid sulfates cannot cross the blood-cell barrier and have to use transporters. Their efflux is mediated by specific transporters of the ATP binding cassette protein group, which thus are further factors controlling their physiological effects. Steroid sulfates, especially dehydroepiandrosterone sulfate (DHEAS) are neuroactive steroids, with well-known effects as allosteric modulators of some neurotransmitter receptors, functioning as ion channels, such as gamma-aminobutyric acid, type A (GABAA) receptors or N-methyl-D-aspartate (NMDA) receptors. In this minireview, we highlight some recent findings of non-genomic steroid sulfate actions through specific G-protein coupled receptors (GPCR), which we believe show the way of further research. A few studies have even indicated that sulfates such as DHEAS may even indirectly regulate gene expression via ligand binding to the membrane receptor and, through G-protein and second messenger formation, activate proteins like cAMP Regulated Elements Binding protein (CREB), which then binds to regulated DNA elements of the expressed gene, in a "classical" genomic effect.

Biosynthesis of estetrol in human pregnancy: Potential pathways

Estetrol (E4) has emerged as a novel and highly promising estrogen for therapeutic use. E4 is a weak natural estrogen produced only in pregnancy. Because of its novelty, there is considerable interest by clinicians in how it is produced in pregnancy. Although the fetal liver plays a key role in its production, the placenta is also involved. A current view is that estradiol (E2) formed in the placenta enters the fetal compartment and is then rapidly sulfated. E2 sulfate then undergoes 15α-/16α-hydroxylation in the fetal liver thereby forming E4 sulfate (phenolic pathway). However, another pathway involving 15α,16α-dihydroxy-DHEAS formed in the fetal liver and converted to E4 in the placenta also plays a significant role (neutral pathway). It is not known which pathway predominates, but both pathways appear to be important in E4 biosynthesis. In this commentary, we summarize the well-established pathways in the formation of estrogens in the nonpregnant and pregnant female. We then review what is known about the biosynthesis of E4 and describe the 2 proposed pathways involving the fetus and placenta.

Role of the Sodium-Dependent Organic Anion Transporter (SOAT/SLC10A6) in Physiology and Pathophysiology

The sodium-dependent organic anion transporter (SOAT, gene symbol SLC10A6) specifically transports 3'- and 17'-monosulfated steroid hormones, such as estrone sulfate and dehydroepiandrosterone sulfate, into specific target cells. These biologically inactive sulfo-conjugated steroids occur in high concentrations in the blood circulation and serve as precursors for the intracrine formation of active estrogens and androgens that contribute to the overall regulation of steroids in many peripheral tissues. Although SOAT expression has been detected in several hormone-responsive peripheral tissues, its quantitative contribution to steroid sulfate uptake in different organs is still not completely clear. Given this fact, the present review provides a comprehensive overview of the current knowledge about the SOAT by summarizing all experimental findings obtained since its first cloning in 2004 and by processing SOAT/SLC10A6-related data from genome-wide protein and mRNA expression databases. In conclusion, despite a significantly increased understanding of the function and physiological significance of the SOAT over the past 20 years, further studies are needed to finally establish it as a potential drug target for endocrine-based therapy of steroid-responsive diseases such as hormone-dependent breast cancer.

The fate of bisphenol A, bisphenol S, and their respective glucuronide metabolites in ovarian cells

Ovarian cells are critical for reproduction and steroidogenesis, which are functions that can be impacted by exposure to xenobiotics. As in other extra-hepatic tissues, biotransformation events may occur at the ovarian level. Such metabolic events deserve interest, notably as they may modulate the overall exposure and toxicity of xenobiotics. In this study, the comparative metabolic fate of two bisphenols was investigated in ovarian cells. Bisphenol A (BPA), a model endocrine disruptor, and its major substitute bisphenol S (BPS) were selected. Bovine granulosa cells (primary cultures) and theca explants (ex vivo tissue) were exposed for 24hr to tritium-labeled BPA, BPS and their respective glucuronides (i.e. their major circulating forms), at concentrations consistent with low-dose exposure scenarios. Mass balance studies were performed, followed by radio-HPLC profiling. The capability of both cell compartments to biotransform BPA and BPS into their respective sulfo-conjugates was demonstrated, with sulfation being the predominant metabolic route. In theca, there was a significantly higher persistence of BPA (compared to BPS) residues over 24hr. Moreover, only theca explants were able to deconjugate inactive BPA-glucuronide and BPS-glucuronide back into their biologically active aglycone forms. Deconjugation rates were demonstrated to be higher for BPS-G than for BPA-G. These findings raise concerns about the in situ direct release of bisphenols at the level of the ovary and demonstrate the relevance of exploring the biotransformation of bisphenols and their circulating metabolites in different ovarian cells with specific metabolic capabilities. This work also provides essential knowledge for the improved risk assessment of bisphenols.

Transfer of quercetin ingested by maternal mice to neonatal mice via breast milk

This is the first study that quantified quercetin (QUE) and its 16 metabolites in the breast milk of QUE-fed maternal mice, the plasma and urine of that, and neonatal mice. Interestingly, the QUE aglycone concentration in the milk was much higher than in the plasma of maternal mice, suggesting that QUE may exert biological activity in neonates.

A 'new' estrogen metabolite: an epoxide of estrone as a sulfated steroid

Current heightened recognition of the importance of sulfated steroids led to the examination of conjugates in media from incubations of estrogens in tissues from the reproductive tract of stallions. Previously, we had reported a 'new' unidentified metabolite of estrone (E1) and [3H]-E1, located between 17β-estradiol (E2) and E1 reference standards on chromatography (HPLC) and identified tentatively as a stable 5α,6α-estrone epoxide. Stallion tissues were minced and incubated for 2 h with [3H]-E1 (1 × 106 cpm). Solid-phase extraction of unconjugated and conjugated steroids from media was followed by liquid scintillation counting (LSC), where radioactivity was mostly in the conjugate fractions (>80%). HPLC of conjugated steroids used an isocratic solvent system of acetonitrile/water (8:92) at 700 µL/min with detection by LSC. A radioactive peak between reference standards of E1 and E2 sulfates was examined, after solvolysis, in a second solvent system. Sulfated steroids yielded largely E1, whereas acid treatment of the unconjugated E1 epoxide had earlier formed 6α-OH-E1 almost exclusively. With sulfatase enzyme, at neutral pH, radioactivity was also seen mostly as E1 with trace amounts of polar material. Reduction with KBH4, however, led also to desulfation; radioactivity had alignment with E2 but even more had low retention times as for 6α/6β-OH-E2. These findings point to a different hydrolysis for desulfation; even more, they reveal an additional oxygen atom at C6 and are supportive of biological formation of 5α,6α-epoxides of E1 and E2. As possible alternatives to catechol estrogens, implicated in cancer, the 'new' estrogen metabolites and their sulfated forms may have special interest.

Sex at the interface: the origin and impact of sex differences in the developing human placenta

The fetal placenta is a source of hormones and immune factors that play a vital role in maintaining pregnancy and facilitating fetal growth. Cells in this extraembryonic compartment match the chromosomal sex of the embryo itself. Sex differences have been observed in common gestational pathologies, highlighting the importance of maternal immune tolerance to the fetal compartment. Over the past decade, several studies examining placentas from term pregnancies have revealed widespread sex differences in hormone signaling, immune signaling, and metabolic functions. Given the rapid and dynamic development of the human placenta, sex differences that exist at term (37–42 weeks gestation) are unlikely to align precisely with those present at earlier stages when the fetal–maternal interface is being formed and the foundations of a healthy or diseased pregnancy are established. While fetal sex as a variable is often left unreported in studies performing transcriptomic profiling of the first-trimester human placenta, four recent studies have specifically examined fetal sex in early human placental development. In this review, we discuss the findings from these publications and consider the evidence for the genetic, hormonal, and immune mechanisms that are theorized to account for sex differences in early human placenta. We also highlight the cellular and molecular processes that are most likely to be impacted by fetal sex and the evolutionary pressures that may have given rise to these differences. With growing recognition of the fetal origins of health and disease, it is important to shed light on sex differences in early prenatal development, as these observations may unlock insight into the foundations of sex-biased pathologies that emerge later in life.

Placental sex differences exist from early prenatal development, and may help explain sex differences in pregnancy outcomes.

Transcriptome profiling of early to mid-gestation placenta reveals that immune signaling is a hub of early prenatal sex differences.

Differentially expressed genes between male and female placenta fall into the following functional associations: chromatin modification, transcription, splicing, translation, signal transduction, metabolic regulation, cell death and autophagy regulation, ubiquitination, cell adhesion and cell–cell interaction.

Placental sex differences likely reflect the interaction of cell-intrinsic chromosome complement with extrinsic endocrine signals from the fetal compartment that accompany gonadal differentiation.

Understanding the mechanisms behind sex differences in placental development and function will provide key insight into molecular targets that can be modulated to improve sex-biased obstetrical complications.

Circulatory Metabolomics Reveals the Association of the Metabolites With Clinical Features in the Patients With Intrahepatic Cholestasis of Pregnancy

Objective: Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of adverse pregnancy to the mother and fetus. As yet, the metabolic profiles and the association of the clinical features remain obscure.

Methods: Fifty-seven healthy pregnant women and 52 patients with ICP were recruited in this study. Plasma samples were collected from pregnancies who received prenatal care between 30 and 36 weeks. Untargeted metabolomics to portray the metabolic profiles were performed by LC/MS. Multivariate combined with the univariate analysis was performed to screen out differential metabolites between the ICP and control groups. A de-biased sparse partial correlation (DSPC) network analysis of differential metabolites was conducted to explore the potential mutual regulation among metabolites on the basis of de-sparsified graphical lasso modeling. The pathway analysis was carried out using MetaboAnalyst. Linear regression and Pearson correlation analysis was applied to analyze correlations of bile acid levels, metabolites, newborn weights, and pregnancy outcomes in ICP patients.

Results: Conspicuous metabolic changes and choreographed metabolic profiles were disclosed: 125 annotated metabolites and 18 metabolic pathways were disturbed in ICP patients. DSPC networks indicated dense interactions among amino acids and their derivatives, bile acids, carbohydrates, and organic acids. The levels of total bile acid (TBA) were increased in ICP patients with meconium-stained amniotic fluid (MSAF) compared with those without MSAF. An abnormal tryptophan metabolism, elevated long chain saturated fatty acids and estrone sulfate levels, and a low-antioxidant capacity were relevant to increased bile acid levels. Newborn weights were significantly associated with the levels of bile acids and some metabolites of amino acids.

Conclusion: Our study revealed the metabolomic profiles in circulation and the correlation of the metabolites with clinical features in ICP patients. Our data suggest that disturbances in metabolic pathways might be associated with adverse pregnancy outcomes.

Reproductive Hormones Mediate Intestinal Microbiota Shifts during Estrus Synchronization in Grazing Simmental Cows

To study shifts in the intestinal microbiota during estrus synchronization in ruminants, we characterized the intestinal microbiota in grazing Simmental cows and the possible mechanism that mediates this shift. Fourteen postpartum Simmental beef cows were synchronized beginning on day 0 (D0) with a controlled internal release device (CIDR), and cloprostenol was injected on D9 when the CIDR was withdrawn. Synchronization ended with timed artificial insemination on D12. Serum and rectal samples harvested on D0, D9, and D12 were analyzed to assess the reproductive hormones and microbiota. Reproductive hormones in the serum of the host were measured using enzyme-linked immunosorbent assay. The microbiota was characterized using 16S rRNA sequencing of the V3−V4 hypervariable region, alpha diversity and beta diversity analyses (principal coordinate analysis, PCoA), cladogram of the linear discriminant analysis effect size (LEfSe) analysis, and microbiota function analysis. Levels of the reproductive hormones, except gonadotropin-releasing hormone (p > 0.05), shifted among D0, D9, and D12 (p < 0.05). Decreased community diversity (Chao1 and ACE) was observed on D12 compared with D0 (p < 0.05). The beta diversity (PCoA) of the microbiota shifted markedly among D0, D9, and D12 (p < 0.05). The LEfSe analysis revealed shifts in the intestinal microbiota communities among D0, D9, and D12 (p < 0.05 and LDA cutoff >3.0). The KEGG pathway analysis showed that carbohydrate metabolism, genetic information and processing, the excretory system, cellular processes and signaling, immune system diseases, and the metabolism were altered (p < 0.05). Reproductive hormones (especially estradiol) were correlated with the alpha diversity indices, beta diversity indices, and an abundance of biomarkers of the shifting intestinal microbiota (p < 0.05). In conclusion, the structure, composition, and function of the intestinal microbiota were shifted during estrus synchronization in a grazing Simmental cow model, and these shifts were mediated by reproductive hormones.

Online In-Tube Solid-Phase Microextraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry for Automated Analysis of Four Sulfated Steroid Metabolites in Saliva Samples

Accurate measurement of sulfated steroid metabolite concentrations can not only enable the elucidation of the mechanisms regulating steroid metabolism, but also lead to the diagnosis of various related diseases. The present study describes a simple and sensitive method for the simultaneous determination of four sulfated steroid metabolites in saliva, pregnenolone sulfate (PREGS), dehydroepiandrosterone sulfate (DHEAS), cortisol sulfate (CRTS), and 17β-estradiol-3-sulfate (E2S), by online coupling of in-tube solid-phase microextraction (IT-SPME) and stable isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). These compounds were extracted and concentrated on Supel-Q PLOT capillary tubes by IT-SPME and separated and detected within 6 min by LC-MS/MS using an InertSustain swift C18 column and negative ion mode multiple reaction monitoring systems. These operations were fully automated by an online program. Calibration curves using their stable isotope-labeled internal standards showed good linearity in the range of 0.01-2 ng mL^-1 for PREGS, DHEAS, and CRTS and of 0.05-10 ng mL^-1 for E2S. The limits of detection (S/N = 3) of PREGS, DHEAS, CRTS, and E2S were 0.59, 0.30, 0.80, and 3.20 pg mL^-1, respectively. Moreover, intraday and interday variations were lower than 11.1% (n = 5). The recoveries of these compounds from saliva samples were in the range of 86.6-112.9%. The developed method is highly sensitive and specific and can easily measure sulfated steroid metabolite concentrations in 50 μL saliva samples.

Role of Uptake Transporters OAT4, OATP2A1, and OATP1A2 in Human Placental Bio-disposition of Pravastatin

Pravastatin is currently under evaluation for prevention of preeclampsia. Factors contributing to placental disposition of pravastatin are important in assessment of potential undesirable fetal effects. The purpose of this study was to identify the uptake transporters that contribute to the placental disposition of pravastatin. Our data revealed the expression of organic anion transporting polypeptide 1A2 (OATP1A2) and OATP2A1 in the apical, and OATP2B1 and OATP5A1 in the basolateral membranes of the placenta, while organic anion transporter 4 (OAT4) exhibited higher expression in basolateral membrane but was detected in both membranes. Preloading placental membrane vesicles with glutarate increased the uptake of pravastatin suggesting involvement of glutarate-dependent transporters such as OAT4. In the HEK293 cells overexpressing individual uptake transporters, OATP2A1, OATP1A2 and OAT4 were determined to accept pravastatin as a substrate at physiological pH, while the uptake of pravastatin by OATP2B1 (known to interact with pravastatin at acidic pH) and OATP5A1 was not detected at pH 7.4. These findings led us to propose that OATP1A2 and OATP2A1 are responsible for the placental uptake of pravastatin from the maternal circulation, while OAT4 mediates the passage of the drug across placental basolateral membrane in the fetal-to-maternal direction.

Multitasking Na+/Taurocholate Cotransporting Polypeptide (NTCP) as a Drug Target for HBV Infection: From Protein Engineering to Drug Discovery

Hepatitis B virus (HBV) infections are among the major public health concerns worldwide with more than 250 million of chronically ill individuals. Many of them are additionally infected with the Hepatitis D virus, a satellite virus to HBV. Chronic infection frequently leads to serious liver diseases including cirrhosis and hepatocellular carcinoma, the most common type of liver cancer. Although current antiviral therapies can control HBV replication and slow down disease progress, there is an unmet medical need to identify therapies to cure this chronic infectious disease. Lately, a noteworthy progress in fighting against HBV has been made by identification of the high-affinity hepatic host receptor for HBV and HDV, namely Na⁺/taurocholate cotransporting polypeptide (NTCP, gene symbol SLC10A1). Next to its primary function as hepatic uptake transporter for bile acids, NTCP is essential for the cellular entry of HBV and HDV into hepatocytes. Due to this high-ranking discovery, NTCP has become a valuable target for drug development strategies for HBV/HDV-infected patients. In this review, we will focus on a newly predicted three-dimensional NTCP model that was generated using computational approaches and discuss its value in understanding the NTCP’s membrane topology, substrate and virus binding taking place in plasma membranes. We will review existing data on structural, functional, and biological consequences of amino acid residue changes and mutations that lead to loss of NTCP’s transport and virus receptor functions. Finally, we will discuss new directions for future investigations aiming at development of new NTCP-based HBV entry blockers that inhibit HBV tropism in human hepatocytes.

Circulating Innate Lymphoid Cells Exhibit Distinctive Distribution During Normal Pregnancy

Over the past decades, the investigation of innate lymphoid cells (ILCs) has revealed their significance in successful pregnancy. Sex hormones, such as estradiol and progesterone, show specific changes during pregnancy and modulate both adaptive and innate immune systems. ILC subset distribution in peripheral blood of pregnant women and its potential association with sex hormone levels have not been well revealed. Peripheral blood was obtained from healthy non-pregnant, early-pregnant, and late-pregnant women. Radioimmunoassay was performed to measure plasma estradiol and progesterone levels. The levels of type 1 ILCs (ILC1s), type 2 ILCs (ILC2s), type 3 ILCs (ILC3s), and total ILCs as well as estrogen and progesterone receptors of ILC2s in peripheral blood were analyzed using flow cytometry. The proportion of total ILCs and distribution of ILC subsets in peripheral blood changed dynamically during pregnancy. Compared to non-pregnant women, late-pregnant women displayed significantly higher proportion of circulating ILCs, among which ILC2s accounted for the majority in late-pregnant women while a smaller part in others, and ILC3s displayed the opposite. Plasma estradiol and progesterone levels elevated while pregnancy proceeded and the expression of their receptors in ILC2s increased consisted with the proportion of circulating ILC2s. Our work first observed the existence of progesterone receptors in human circulating ILC2s and revealed the distribution pattern of circulating ILC subsets and their interrelation with plasma sex hormone levels during pregnancy. Our results suggested that the estradiol and progesterone levels might partly influence the distribution of circulating ILC subsets and implied the interplay between circulating ILCs and pregnancy.

American Bison (Bison bison) reproductive endocrinology: serum Pregnancy Associated Glycoproteins (PAG), Progesterone, Estrone and Estrone-Sulfate in non pregnant animals and during gestation

This study describes concentrations of Pregnancy Associated Glycoproteins (PAG), progesterone (P4), estrone (E1) and estrone-sulfate (E1S) in American Bison sera. In 2 ranches, mature American Bison were sampled once a year for 2 yr. Subsequent American Bison cows calving days were reported. PAG concentration was determined by Radio-Immuno Assay, whereas P4, E1 and E1S were assayed using Liquid Chromatography and Mass Spectrometry. Concentrations were compared between American Bison bulls (B, n = 7), Nonpregnant cows (NP, n = 32), first (1TP, n = 3), second (2TP, n = 26) and third (3TP, n = 15) trimester of pregnancy. Seven American Bison bulls and 92 cows were sampled, 51 calved during these 2 yr. Calving occurred mostly in spring (74.5%), but also in summer (13.7%) and fall (11.8%). PAG and P4 were higher in 2TP and 3TP than B and NP (P< 0.0001). P4 was non-basal in B and NP. E1 and E1S were correlated (P< 0.0001; r = 0.76) and increased in 2TP and 3TP when compared with B and NP (P< 0.01). Moreover, E1S was higher in 3TP than in 2TP (P< 0.0001) and correlated to pregnancy day (P< 0.0001; r = 0.60). Breeding American Bison in Belgium induces a calving seasonality loss. P4 slowly increases in 1TP and remains steady and high in 2 and 3TP. P4 non-basal and variable concentrations in B or NP disable its use as gestation marker. American Bison produce PAG in the 2 and 3TP, but Estrone-sulfate assay seems to be the best pregnancy marker during the 2 last trimesters as it could help to estimate the gestation period.

Role of sex steroids and prostaglandins during the luteal life cycle in domestic cats and lynxes

Although lynxes and domestic cats are both felids, their luteal life cycles differ. As in many species, corpora lutea (CLs) of domestic cats regress after pregnancy or pseudopregnancy. By contrast, CLs of lynxes do not functionally regress following the cycle of their formation. They stay physiologically active and persist for several years. To obtain an improved understanding of the life cycle of both species, we comparatively studied the CLs of these species in detail. In this review, we summarize the similarities and differences of their CLs regarding sex steroid and prostaglandin generation and receptors. The most evident differences were visible in the CLs of lynxes, which persist from previous cycles, compared with CLs of lynxes and domestic cats from the recent luteal cycle. We assume that these differences could indicate processes ensuring long-term luteal survival and functionality, for example, by high estrogen production/metabolism or by antioxidative effects.

17β-Estradiol Enhances Porcine Meiosis Resumption from Autophagy-Induced Gap Junction Intercellular Communications and Connexin 43 Phosphorylation via the MEK/ERK Signaling Pathway

Estrogen and its analogues are ubiquitous in agricultural environments, with large biological functions of oocyte development. Gap junction intercellular communications (GJICs) are the structural basis in cumulus-oocyte complexes (COCs) and regulate oocyte maturation and developmental material transport through a number of pathways. This study mainly determines the effect and potential mechanism of estrogen (17β-estradiol) in regulating GJICs in porcine COCs. In our study, 17β-estradiol increased porcine nuclear maturation in a time-dependent manner. The analysis revealed that 17β-estradiol upregulated the autophagy in COCs during in vitro maturation. In contrast with the control, 17β-estradiol decreased GJICs in a time-dependent manner between cumulus cells and oocytes, while it was consistent with the control group at 24 h. Carbenoxolone (CBX) blocks GJICs as a negative control group used in our system. Autophagy inhibitor autophinib decreased oocyte maturation, and the reduced nuclear maturation treated with autophinib was abolished by 17β-estradiol. Besides, the upregulation effect of autophinib on GJICs and transzonal projections (TZPs) was decreased by 17β-estradiol. 17β-Estradiol could reduce serine 368 phosphorylation of connexin 43 (Cx43) protein by autophinib in porcine COCs. These results were dependent upon the MEK/ERK signaling pathway. Furthermore, 17β-estradiol-induced GJICs and Cx43 phosphorylation were inhibited by autophinib or the MEK/ERK pathway inhibitors (Trametinib and FR 180204), indicating that 17β-estradiol regulated GJICs through the MEK/ERK signaling pathway. In conclusion, 17β-estradiol improves the autophagy-mediated nuclear maturation with downregulating GJICs and TZPs in porcine COCs. Such an effect occurs by phosphorylation of Cx43, which was regulated via the MEK/ERK signaling pathway.

G protein-coupled estrogen receptor signaling dependent epidermal growth-like factor expression is required for NPR2 inhibition and meiotic resumption in goat oocytes

G protein-coupled estrogen receptor (GPER), which is different from traditional estrogen nuclear receptors (ERs), mediates the rapid transduction of nongenomic signals in cells, and works by regulating transcription and intracellular second messengers. Studies have shown that GPER may regulate oocyte maturation, but the relevant mechanism is not entirely clear. Here, goat cumulus-oocyte complexes (COCs) were used as a model to explore the regulation and mechanism of GPER on oocyte maturation. Our study showed that 17β-estradiol (E₂) significantly reduced cyclic guanosine monophosphate (cGMP) synthesis in COCs and accelerated the meiotic resumption of goat oocytes via GPER. Further investigation found that GPER mediated the downregulation of natriuretic peptide receptor 2 (NPR2) protein expression in goat cumulus cells by E₂. In addition, we found that E₂ significantly upregulated the mRNA levels of epidermal growth (EGF)-like factors in goat cumulus cells through GPER, and activated the downstream EGF receptor (EGFR) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways. Both AG1478 (EGFR inhibitor) and U0126 (ERK1/2 inhibitor) abolished the inhibitory effect of E₂ on the protein expression of NPR2. These results indicate that, through GPER, E₂ upregulates the mRNA levels of EGF-like factors in goat cumulus cells and activates the downstream EGF signaling network to suppress the expression of NPR2 protein, which results in a decrease in cGMP synthesis and acceleration of meiotic resumption in goat oocytes.

Simultaneous expression of steroid sulfatase and androgen receptor reduced overall survival of patients with epithelial ovarian tumors

BACKGROUND

Ovarian cancer is usually diagnosed at an advanced stage due to its early asymptomatic course and late-stage non-specific symptoms. This highlights the importance of researching the molecular mechanisms involved in ovarian carcinogenesis as well as the discovery of novel prognostic markers that could help improve the survival outcome of patients. The aim of this study was to evaluate the expression of the steroid sulfatase (STS) in 154 samples of primary ovarian tumors. This protein is crucial in the intracellular conversion of sulfated steroid hormones to active steroid hormones. The presence of STS, 3β-HSD, and 17β-HSD1 result in the production of testosterone which act through the androgen receptor (AR) in the tumor cell. The presence of STS and AR in epithelial ovarian tumors and their association to the overall survival of patients was evaluated using Kaplan-Meier and Cox regression analyses.

RESULTS

Immunoreactivity for STS was detected in 65% of the tumors and no association was observed with histological subtypes and clinical stages of the tumor. The STS expression in the tumors exhibiting immunoreactive AR resulted in a reduced survival (log-rank test, p = 0.032) and a risk factor in univariate and multivariate analysis, HR = 3.46, CI_95% 1.00-11.92, p = 0.049 and HR = 5.92, CI_95% 1.34-26.09, p = 0.019, respectively.

CONCLUSIONS

These findings suggest that the intracellular synthesis of testosterone acting through its receptor can promote tumor growth and progression. Moreover, the simultaneous expression of STS and AR constitutes an independent predictor of poor prognosis in epithelial ovarian tumors.

Steroid sulfates in domestic mammals and laboratory rodents

Historically steroid sulfates have been considered predominantly as inactive metabolites. It was later discovered that by cleavage of the sulfate residue by steroid sulfatase (STS), they can be (re-)converted into active forms or into precursors for the local production of active steroids. This sulfatase pathway is now a very active field of research, which has gained considerable interest particularly in connection with the steroid metabolism of human steroid hormone-dependent cancer tissue. In comparison, there is much less information available on the occurrence of the sulfatase pathway in physiological settings, where the targeted uptake of steroid sulfates by specific transporters and their hydrolysis could serve to limit steroid effects to a subgroup of potentially steroid responsive cells. In humans, steroid sulfates of adrenal origin circulate in intriguingly high concentrations throughout most of life. Thus, ample substrate is available for the sulfatase pathway regardless of sex. However, the abundant adrenal output of steroid sulfates is a specific feature of select primates. Compared to humans, in our domestic mammals (dogs, cats, domestic ungulates) and laboratory rodents (mouse, rat) research into the biology of steroid sulfates is still in its infancy and information on the subject has so far been largely limited to punctual observations, which indicate considerable species-specific peculiarities. The aim of this overview is to provide a summary of the relevant information available in the above-mentioned species, predominantly taking into account data on concentrations of steroid sulfates in blood as well as the expression patterns and activities of relevant sulfotransferases and STS.

Substrate Specificities and Inhibition Pattern of the Solute Carrier Family 10 Members NTCP, ASBT and SOAT

Three carriers of the solute carrier family SLC10 have been functionally characterized so far. Na⁺/taurocholate cotransporting polypeptide NTCP is a hepatic bile acid transporter and the cellular entry receptor for the hepatitis B and D viruses. Its intestinal counterpart, apical sodium-dependent bile acid transporter ASBT, is responsible for the reabsorption of bile acids from the intestinal lumen. In addition, sodium-dependent organic anion transporter SOAT specifically transports sulfated steroid hormones, but not bile acids. All three carriers show high sequence homology, but significant differences in substrate recognition that makes a systematic structure-activity comparison attractive in order to define the protein domains involved in substrate binding and transport. By using stably transfected NTCP-, ASBT-, and SOAT-HEK293 cells, systematic comparative transport and inhibition experiments were performed with more than 20 bile acid and steroid substrates as well as different inhibitors. Taurolithocholic acid (TLC) was identified as the first common substrate of NTCP, ASBT and SOAT with K _m values of 18.4, 5.9, and 19.3 µM, respectively. In contrast, lithocholic acid was the only bile acid that was not transported by any of these carriers. Troglitazone, BSP and erythrosine B were identified as pan-SLC10 inhibitors, whereas cyclosporine A, irbesartan, ginkgolic acid 17:1, and betulinic acid only inhibited NTCP and SOAT, but not ASBT. The HBV/HDV-derived myr-preS1 peptide showed equipotent inhibition of the NTCP-mediated substrate transport of taurocholic acid (TC), dehydroepiandrosterone sulfate (DHEAS), and TLC with IC₅₀ values of 182 nM, 167 nM, and 316 nM, respectively. In contrast, TLC was more potent to inhibit myr-preS1 peptide binding to NTCP with IC₅₀ of 4.3 µM compared to TC (IC₅₀ = 70.4 µM) and DHEAS (IC₅₀ = 52.0 µM). Based on the data of the present study, we propose several overlapping, but differently active binding sites for substrates and inhibitors in the carriers NTCP, ASBT, SOAT.

A guide to plasma membrane solute carrier proteins

This review aims to serve as an introduction to the solute carrier proteins (SLC) superfamily of transporter proteins and their roles in human cells. The SLC superfamily currently includes 458 transport proteins in 65 families that carry a wide variety of substances across cellular membranes. While members of this superfamily are found throughout cellular organelles, this review focuses on transporters expressed at the plasma membrane. At the cell surface, SLC proteins may be viewed as gatekeepers of the cellular milieu, dynamically responding to different metabolic states. With altered metabolism being one of the hallmarks of cancer, we also briefly review the roles that surface SLC proteins play in the development and progression of cancer through their influence on regulating metabolism and environmental conditions.

Effect of follicle size on hormonal status of follicular fluid, oocyte ATP content, and in vitro embryo production in prepubertal sheep

The aim of this study was to assess the effect of follicular size on estradiol (E₂) and progesterone (P₄) levels in intrafollicular fluid, ATP content in oocytes, and the embryo development rate in prepubertal sheep. Slaughterhouse ovaries were dissected to recover the follicles, which were classified according to the follicle diameter as <3 mm (n = 20) and ≥3 mm (n = 17). Then, follicular fluid was obtained and analyzed by radioimmunoassay to determine the E₂ and P₄ concentrations. Another group of ovaries was used to recover cumulus-oocyte complexes according to follicle size. In vitro maturation (IVM), in vitro fertilization (IVF), and embryo culture were performed using standard procedures, and ATP level was assessed at 0 and 24 h of IVM. Intrafollicular concentrations of E₂ and P₄ and E₂:P₄ ratio were higher in ≥3 mm (18.7 ± 5.9 ng/mL, 7.8 ± 1.2 ng/mL, and 3.6 ± 1.3, respectively) than <3 mm (1.8 ± 0.4 ng/mL, 2.6 ± 0.3 ng/mL and 0.9 ± 0.3, respectively) follicles. The rate of ATP increased during IVM and was higher in oocytes from ≥3 mm than <3 mm (22.4 ± 0.7 and 8.6 ± 2.2-fold change; respectively) follicles. After IVF, the blastocyst development was higher in oocytes recovered from ≥3 mm (11.1 ± 0.9%) than from <3 mm (6.5 ± 0.7%) follicles. These results indicate an improvement in the competence and development of oocytes from ≥3 mm follicles with a higher E₂:P₄ ratio. Thus, this ratio could be used as reference to design IVM medium and to enhance the in vitro embryo production in lambs.

Chronic Exposure to 4-Nonylphenol Alters UDP-Glycosyltransferase and Sulfotransferase Clearance of Steroids in the Hard Coral, Pocillopora damicornis

The effects of the xenoestrogen 4-nonylphenol (4NP) on endocrine and metabolic homeostasis in the reef building coral, Pocillopora damicornis were investigated. The aim was to understand if ubiquitous nonylphenol ethoxylate contaminants in the marine environment result in altered homeostatic function. Coral colonies were chronically exposed (6 weeks) to a sublethal concentration (1 ppb) of 4NP and sampled over the coral's lunar reproductive cycle. Although activity of steroidogenic enzymes [cytochrome P450 (CYP) 17, CYP 19, and 3-β-Hydroxysteroid dehydrogenase] and the conjugation enzyme glutathione-S-transferase was not altered, significant increases in the activity of the steroid clearing enzyme UDP-glycosyltransferase (UGT) were observed. The natural fluctuation of UGT activity with the lunar cycle was replaced with consistently high UGT activity throughout the reproductive cycle during 4NP exposure. No effect of 4NP on the reverse reaction, mediated by β-glucuronidase, was observed. Thus, 4NP shifts the UGT:β-glucuronidase ratio toward greater clearance at points in the lunar cycle where retention of compounds is typically favored. Additionally, 4NP reduced activity of the steroid regeneration enzyme steroid sulfatase, further shifting the system toward clearance rather than regeneration. These data imply that environmentally relevant levels of 4NP may be impacting the reproductive health of corals and threatening the persistence of coral reefs.

Longitudinal study on steroid hormone variations during the second trimester of gestation: a useful tool to confirm adequate foetal development

Background

The interaction of hormonal factors are crucial for good foetal development. During the second trimester of gestation, most of the main physiological processes of foetal development occur. Therefore, the aim of this study was to determine the variations in the physiological levels of cortisol, estriol, estrone sulphate, and progesterone during the second trimester (weeks 12–26) in order to establish normal ranges that can serve as indicators of foetal well-being and good functioning of the foetal-placental unit.

Methods

Saliva samples from 106 pregnant women were collected weekly (from week 12 to week 26 of gestation), and hormonal measurements were assayed by an enzyme immunoassay. The technique used for hormone measurements was highly sensitive and served as a non-invasive method for sample collection.

Results

The results revealed a statistically significant (p<0.05) difference between cortisol, progesterone, and oestrogens throughout the second trimester, with a more substantial relationship between oestrogens and progesterone [P4-E3 (r=0.427); P4-E1SO4 (r=0.419)]. By analysing these hormone concentrations, statistically significant (p<0.05) elevations in progesterone, cortisol, and estriol levels were found at the 16^th [(P4 (0.78±0.088), C(1.99±0.116), E3(2.513±0.114)]; 18th [(P4 (1.116±0.144), C(3.409±0.137), E3(3.043±0.123)] and 23rd week of gestation [(P4(1.36±0.153), C(1.936±0.11), E3(2.657±0.07)]. Estrone sulphate levels appeared to increase progressively throughout the second trimester [from 1.103±0.03 to 2.244±0.09].

Conclusion

The 18th week of gestation seems to constitute a very important week during foetal adrenal development, and the analysis of the main hormones involved in foetal development, provided more precise information regarding the proper functioning of the foetal unit and foetal development.

Steroid hormones sulfatase inactivation extends lifespan and ameliorates age-related diseases

Aging and fertility are two interconnected processes. From invertebrates to mammals, absence of the germline increases longevity. Here we show that loss of function of sul-2, the Caenorhabditis elegans steroid sulfatase (STS), raises the pool of sulfated steroid hormones, increases longevity and ameliorates protein aggregation diseases. This increased longevity requires factors involved in germline-mediated longevity (daf-16, daf-12, kri-1, tcer-1 and daf-36 genes) although sul-2 mutations do not affect fertility. Interestingly, sul-2 is only expressed in sensory neurons, suggesting a regulation of sulfated hormones state by environmental cues. Treatment with the specific STS inhibitor STX64, as well as with testosterone-derived sulfated hormones reproduces the longevity phenotype of sul-2 mutants. Remarkably, those treatments ameliorate protein aggregation diseases in C. elegans, and STX64 also Alzheimer’s disease in a mammalian model. These results open the possibility of reallocating steroid sulfatase inhibitors or derivates for the treatment of aging and aging related diseases.

Sul-2 is a steroid sulfatase in c.elegans. Here the authors show that, in the absence of sul-2 enzymatic activity, worm lifespan is increased, and that chemical inhibition ameliorates symptoms of neurodegenerative disorders in worms and mice.

A new molecular risk pathway for postpartum mood disorders: clues from steroid sulfatase-deficient individuals

Postpartum mood disorders develop shortly after childbirth in a significant proportion of women. These conditions are associated with a range of symptoms including abnormally high or low mood, irritability, cognitive disorganisation, disrupted sleep, hallucinations/delusions, and occasionally suicidal or infanticidal ideation; if not treated promptly, they can substantially impact upon the mother's health, mother-infant bonding, and family dynamics. The biological precipitants of such disorders remain unclear, although large changes in maternal immune and hormonal physiology following childbirth are likely to play a role. Pharmacological therapies for postpartum mood disorders can be effective, but may be associated with side effects, concerns relating to breastfeeding, and teratogenicity risks when used prophylactically. Furthermore, most of the drugs that are used to treat postpartum mood disorders are the same ones that are used to treat mood episodes during non-postpartum periods. A better understanding of the biological factors predisposing to postpartum mood disorders would allow for rational drug development, and the identification of predictive biomarkers to ensure that 'at risk' mothers receive earlier and more effective clinical management. We describe new findings relating to the role of the enzyme steroid sulfatase in maternal postpartum behavioural processes, and discuss how these point to a novel molecular risk pathway underlying postpartum mood disorders. Specifically, we suggest that aberrant steroid hormone-dependent regulation of neuronal calcium influx via extracellular matrix proteins and membrane receptors involved in responding to the cell's microenvironment might be important. Testing of this hypothesis might identify novel therapeutic targets and predictive biomarkers.

Targeted LC-MS/MS analysis of steroid glucuronides in human urine

Conjugation with glucuronic acid is one of the major metabolic reactions in human steroid hormone catabolism. Recently, increasing interest has been raised concerning the biological roles of steroid glucuronides. We have therefore developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of 15 urinary steroid hormone glucuronides in human urine: androsterone glucuronide (An-G), etiocholanolone glucuronide (Etio-G), epiandrosterone glucuronide (epiAn-G), dihydrotestosterone glucuronide (DHT-G), dehydroepiandrosterone glucuronide (DHEA-G), testosterone glucuronide (T-G), epitestosterone glucuronide (epiT-G), estrone glucuronide (E1-3 G), 17β-estradiol 17-glucuronide (E2-17 G), 17β-estradiol 3-glucuronide (E2-3 G), estriol 16-glucuronide (E3-16 G), pregnenolone glucuronide (Preg-G), tetrahydro-11-deoxycorticosterone 3-glucuronide (THDOC-3 G), cortisol 21-glucuronide (F-G) and pregnanediol glucuronide (PD-G). Sample workup included protein precipitation and solid phase extraction. Internal standards were used to correct for the loss of analytes during sample preparation and analysis. The method showed good linearity (R²≥0.99) and recovery ranged from 89.6 % to 113.8 %. Limit of quantification ranged from 1.9 nmol/L for F-G to 21.4 nmol/L for An-G. Intra-day and inter-day accuracy and precision were below 15 % for all quality controls. The method was successfully applied to 67 urine samples from children and adolescents in whom total concentrations of free and conjugated steroids had been previously determined by GC-MS after enzymatic hydrolysis. Free and sulfated steroids were also measured by LC-MS/MS. In general, the sums of the respective glucuronidated, sulfated and free forms of an analyte corresponded well with its total amount determined after enzymatic hydrolysis by GC-MS. Regarding the most prominent steroid metabolites, the total mean levels of androsterone and etiocholanolone showed an increase up to 5820.0 nmol/L and 4017.8 nmol/L in the group of 15-20 year-old children, respectively. Glucuronide conjugates (4374.3 nmol/L and 3588.5 nmol/L, respectively) dominated. DHEA was excreted mostly as sulfate (0-1 month of age: 184.5 nmol/L; 15-20 years of age: 1618.4 nmol/L) in all age groups. Cortisol was present predominantly as sulfate (mean: 173.8 nmol/L) in newborns. Levels of sulfated cortisol decreased with age, its glucuronidated form increased. The levels of free cortisol were relatively constant throughout childhood. Sex hormones were preferably excreted as glucuronides. In general, steroid hormone metabolites were conjugated to various extents with glucuronic acid or sulfuric acid and their ratio changed over lifetime.

Blood Metabolomic Profiling Confirms and Identifies Biomarkers of Food Intake

Metabolomics can be a tool to identify dietary biomarkers. However, reported food-metabolite associations have been inconsistent, and there is a need to explore further associations. Our aims were to confirm previously reported food-metabolite associations and to identify novel food-metabolite associations. We conducted a cross-sectional analysis of data from 849 participants (57% men) of the PopGen cohort. Dietary intake was obtained using FFQ and serum metabolites were profiled by an untargeted metabolomics approach. We conducted a systematic literature search to identify previously reported food-metabolite associations and analyzed these associations using linear regression. To identify potential novel food-metabolite associations, datasets were split into training and test datasets and linear regression models were fitted to the training datasets. Significant food-metabolite associations were evaluated in the test datasets. Models were adjusted for covariates. In the literature, we identified 82 food-metabolite associations. Of these, 44 associations were testable in our data and confirmed associations of coffee with 12 metabolites, of fish with five, of chocolate with two, of alcohol with four, and of butter, poultry and wine with one metabolite each. We did not identify novel food-metabolite associations; however, some associations were sex-specific. Potential use of some metabolites as biomarkers should consider sex differences in metabolism.

Estrogen improves the development of yak (Bos grunniens) oocytes by targeting cumulus expansion and levels of oocyte-secreted factors during in vitro maturation

The estrogen-signalling pathway is critical for normal follicular development; however, little is known about its importance during in vitro maturation (IVM) in large animals, particularly yaks (Bos grunniens). Through the present study, we aimed to determine the mechanisms underlying estrogen involvement in cumulus expansion and the subsequent development of cumulus-oocyte complexes (COCs). COCs were cultured in the maturation medium supplemented with different concentrations (10⁻⁶–10⁻³ mM) of 17β-estradiol (E2) or its receptor antagonist, fulvestrant, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blot were performed to determine the expression of cumulus-expansion related factors and oocyte-secreted factors (OSFs). The cumulus expansion of COCs was observed using an inverted microscope, and COCs developmental ability were judged by the evaluation of cleavage and blastulation rates per inseminated oocytes by IVF, and the number of cells in the blastocyst. Cumulus expansion increased with 10⁻⁶–10⁻³ mM E2, but decreased with fulvestrant. HAS2, PTGS2, PTX3 and OSFs expression increased in the 10⁻⁶–10⁻³ mM E2 groups. Significantly higher cleavage and blastocyst rates were observed in the 10⁻⁴ mM E2 group than in the fulvestrant and 0 mM E2 groups. Moreover, in the 10⁻⁴ mM group, blastocysts at 7 days had higher cell counts than the other groups. In conclusion, the increase in cumulus expansion and subsequent oocyte development after the addition of E2 to IVM medium may have resulted from increased cumulus-expansion-related factor expression and OSF levels.

Antitumor and hepatoprotective activity of natural and synthetic neo steroids

In this review, steroids with a tertiary butyl group, which are usually called neo steroids, are a small group of natural lipids isolated from higher plants, fungi, marine sponges, and yeast. In addition, steroids with a tertiary butyl group have been synthesized in some laboratories in Canada, USA, Europe, and Japan and their biological activity was studied. Some natural neo steroids demonstrate antitumor or hepatoprotective activities. In addition, synthetic neo steroids exhibit anticancer and neuroprotective properties. However, to confirm the above data, both practical and clinical experimental studies are necessary. Nevertheless, the results may be useful for pharmacologists, chemists, biochemists, and the pharmaceutical industry.

Very High Dehydroepiandrosterone Sulfate (DHEAS) in Serum of an Overweight Female Adolescent Without a Tumor

Introduction: An increase of serum dehydroepiandrosterone (DHEA) sulfate (DHEAS) is observed in premature adrenarche and congenital adrenal hyperplasia. Very high DHEAS levels are typical for adrenal tumors. Approximately 74% of DHEAS is hydrolyzed to DHEA by the steroid sulfatase (STS). The reverse reaction is DHEA sulfation. Besides these two enzyme reactions, the DHEAS transported through the cell membrane is important for its distribution and excretion. Case Presentation: We present a female adolescent with overweight and a very high DHEAS. The presence of a DHEAS-producing tumor was rejected using ultrasonography, Magnetic Resonance Tomography (MRT), and dexamethasone suppression. STS deficiency was suspected. Sequence analysis revealed a heterozygous nonsense mutation which predicts a truncation of the carboxyl region of the STS that is implicated in substrate binding. No partial gene deletion outside exon 5 was detected by multiplex ligation-dependent probe amplification. The bioassay revealed normal enzyme activity in the patient's leukocytes. A defect of transporter proteins was suggested. Both efflux [multidrug-resistance protein (MRP)2 and breast cancer-resistance protein (BCRP)] and uptake [organic anion-transporting polypeptide (OATP) and organic anion transporter (OAT) carriers] transporters were studied. Sequence analysis of exons revealed a heterozygous Q141K variant for BCRP. Conclusions: A novel heterozygous nonsense mutation in the STS gene and a known heterozygous missense variant in the BCRP gene were found. The heterozygous nonsense mutation in the STS gene is not supposed to be responsible for STS deficiency. The BCRP variant is associated with reduced efflux transport activity only in its homozygous state. The combination of the two heterozygous mutations could possibly explain the observed high levels of DHEAS and other sulfated steroids.

Genome-wide analysis of the role of DNA methylation in inbreeding depression of reproduction in Langshan chicken

Inbreeding depression of chicken reproduction is a major concern in the conservation of chicken genetic resources. To investigate the potential DNA methylation sites involved in the inbreeding depression of chicken reproduction, we carried out whole-genome bisulfite sequencing (WGBS) of hypothalamus and ovary tissues from the strongly and weakly inbred Langshan chickens, respectively. 5948 and 4593 differentially methylated regions (DMRs) were identified in the hypothalamus and ovary between the strongly and weakly inbred Langshan chickens, respectively. Large numbers of DMR-related genes (DMGs) were enriched in reproduction-related pathways. By combining the WGBS and transcriptome data, two DMRs in SRD5A1 and CDC27 genes were inferred as the most likely biomarkers of inbreeding depression of reproduction in Langshan chicken. Our study provides the first systematic investigation of the DNA methylation changes in strongly inbred chickens, and extends our understanding of the regulatory mechanisms underlying inbreeding depression in chicken reproduction.

Evaluating the effects on steroidogenesis of estragole and trans-anethole in a feto-placental co-culture model

In this study, we determined whether estragole and its isomer trans-anethole interfered with feto-placental steroidogenesis in a human co-culture model composed of fetal-like adrenocortical (H295R) and placental trophoblast-like (BeWo) cells. Estragole and trans-anethole are considered the biologically active compounds within basil and fennel seed essential oils, respectively. After a 24 h exposure of the co-culture to 2.5, 5.2 and 25 μM estragole or trans-anethole, hormone concentrations of estradiol, estrone, dehydroepiandrosterone, androstenedione, progesterone and estriol were significantly increased. Using RT-qPCR, estragole and trans-anethole were shown to significantly alter the expression of several key steroidogenic enzymes, such as those involved in cholesterol transport and steroid hormone biosynthesis, including StAR, CYP11A1, HSD3B1/2, SULT2A1, and HSD17B1, -4, and -5. Furthermore, we provided mechanistic insight into the ability of estragole and trans-anethole to stimulate promoter-specific expression of CYP19 through activation of the PKA pathway in H295R cells and the PKC pathway in BeWo cells, in both cases associated with increased cAMP levels. Moreover, we show new evidence suggesting a role for progesterone in regulating steroid hormone biosynthesis through regulation of the StAR gene.

Prognostic Relevance of Steroid Sulfation in Adrenocortical Carcinoma Revealed by Molecular Phenotyping Using High-Resolution Mass Spectrometry Imaging

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare tumor with variable prognosis even within the same tumor stage. Cancer-related sex hormones and their sulfated metabolites in body fluids can be used as tumor markers. The role of steroid sulfation in ACC has not yet been studied. MALDI mass spectrometry imaging (MALDI-MSI) is a novel tool for tissue-based chemical phenotyping.

METHODS

We performed phenotyping of formalin-fixed, paraffin-embedded tissue samples from 72 ACC by MALDI-MSI at a metabolomics level.

RESULTS

Tumoral steroid hormone metabolites-estradiol sulfate [hazard ratio (HR) 0.26; 95% CI, 0.10-0.69; P = 0.005] and estrone 3-sulfate (HR 0.22; 95% CI, 0.07-0.63; P = 0.003)-were significantly associated with prognosis in Kaplan-Meier analyses and after multivariable adjustment for age, tumor stage, and sex (HR 0.29; 95% CI, 0.11-0.79; P = 0.015 and HR 0.30; 95% CI, 0.10-0.91; P = 0.033, respectively). Expression of sulfotransferase SULT2A1 was associated with prognosis to a similar extent and was validated to be a prognostic factor in two published data sets. We discovered the presence of estradiol-17β 3,17-disulfate (E2S2) in a subset of tumors with particularly poor overall survival. Electron microscopy revealed novel membrane-delimited organelles in only these tumors. By applying cluster analyses of metabolomic data, 3 sulfation-related phenotypes exhibited specific metabolic features unrelated to steroid metabolism.

CONCLUSIONS

MALDI-MSI provides novel insights into the pathophysiology of ACC. Steroid hormone sulfation may be used for prognostication and treatment stratification. Sulfation-related metabolic reprogramming may be of relevance also in conditions beyond the rare ACC and can be directly investigated by the use of MALDI-MSI.

Comparison of Strategies for the Determination of Sterol Sulfates via GC-MS Leading to a Novel Deconjugation-Derivatization Protocol

Sulfoconjugates of sterols play important roles as neurosteroids, neurotransmitters, and ion channel ligands in health and disease. In most cases, sterol conjugate analysis is performed with liquid chromatography-mass spectrometry. This is a valuable tool for routine analytics with the advantage of direct sterol sulfates analysis without previous cleavage and/or derivatization. The complementary technique gas chromatography-mass spectrometry (GC-MS) is a preeminent discovery tool in the field of sterolomics, but the analysis of sterol sulfates is hampered by mandatory deconjugation and derivatization. Despite the difficulties in sample workup, GC-MS is an indispensable tool for untargeted analysis and steroid profiling. There are no general sample preparation protocols for sterol sulfate analysis using GC-MS. In this study we present a reinvestigation and evaluation of different deconjugation and derivatization procedures with a set of representative sterol sulfates. The advantages and disadvantages of trimethylsilyl (TMS), methyloxime-trimethylsilyl (MO-TMS), and trifluoroacetyl (TFA) derivatives were examined. Different published procedures of sterol sulfate deconjugation, including enzymatic and chemical cleavage, were reinvestigated and examined for diverse sterol sulfates. Finally, we present a new protocol for the chemical cleavage of sterol sulfates, allowing for simultaneous deconjugation and derivatization, simplifying GC-MS based sterol sulfate analysis.

Steroid hormones and pregnancy

Pregnancy is associated with physiological adjustments in order to allow adequate growth and fetal development. In particular, steroids are necessary to maintain in balance numerous functions during gestation. Steroidogenesis in the maternal, placental and fetal compartments and the biological effects of progestins and estrogens that play a pivotal role before and during pregnancy are described. Although it is well-known that androgens are considered as substrate for estrogens biosynthesis, their biosynthesis and functionality in placental and other tissues have been questioned. As compared with healthy pregnancy, steroid hormones levels have been found altered in complicated pregnancies and hormonal treatments have been used is some pathologies. Therefore, the aim of this work was to review the biosynthesis, function and regulation of progestins, androgens and estrogens during gestation. Furthermore, steroid hormones concentrations during healthy and complicated pregnancy as well hormonal therapies for the prevention of miscarriages and preterm deliveries are discussed in the present review.

Concentrations of sulphated estrone, estradiol and dehydroepiandrosterone measured by mass spectrometry in pregnant mares

BACKGROUND

Few studies have provided a longitudinal analysis of systemic concentrations of conjugated oestrogens (and androgens) throughout pregnancy in mares, and those only using immunoassay. The use of liquid chromatography tandem mass spectrometry (LC-MS/MS) will provide more accurate concentrations of circulating conjugated steroids.

OBJECTIVES

To characterise circulating concentrations of individual conjugated steroids throughout equine gestation by using LC-MS/MS.

STUDY DESIGN

Longitudinal study and comparison of pregnant mares treated with vehicle or letrozole in late gestation.

METHODS

Sulphated oestrogens and androgens were measured in mares throughout gestation and mares in late gestation (8-11 months) treated with vehicle or letrozole to inhibit oestrogen synthesis in late gestation. An analytical method was developed using LC-MS/MS to evaluate sulphated estrone, estradiol, testosterone and dehydroepiandrosterone (DHEAS) during equine gestation.

RESULTS

Estrone sulphate concentrations peaked by week 26 at almost 60 μg/mL, 50-fold higher than have been reported in studies using immunoassays. An increase in DHEAS was detected from 7 to 9 weeks of gestation, but concentrations remained consistently low (if detected) for the remainder of gestation and testosterone sulphate was undetectable at any stage. Estradiol sulphate concentrations were highly correlated with estrone sulphate but were a fraction of their level. Concentrations of both oestrogen sulphates decreased from their peak to parturition. Letrozole inhibited estrone and estradiol sulphate concentrations at 9.25 and 10.5 months of gestation but, no increase in DHEAS was observed.

MAIN LIMITATIONS

Limited number of mares sampled and available for analysis, lack of analysis of 5α-reduced and B-ring unsaturated steroids due to lack of available standards.

CONCLUSIONS

Dependent on methods of extraction and chromatography, and the specificity of primary antisera, immunoassays may underestimate oestrogen conjugate concentrations in blood from pregnant mares and may detect androgen conjugates (neither testosterone sulphate nor DHEAS were detected here by LC-MS/MS) that probably peak coincident with oestrogen conjugates between 6 and 7 months of equine gestation.

A tale of two steroids: The importance of the androgens DHEA and DHEAS for early neurodevelopment

DHEA and DHEAS are neuroactive neurosteroids that interact with several major receptor systems in the brain, including sigma (σ), glutamate, and GABA-A receptors. It has been recognized as early as 1952, that the loss of DHEA/DHEAS in adult life is associated with neuropsychiatric disorders (eg schizophrenia, depression). However, the mechanistic role for DHEA/DHEAS in any of these domains remains speculative, not the least because the presence of these androgens in the adrenal gland and brain is largely confined to humans and only some non-human primates. DHEA and DHEAS are dynamically regulated from before birth and before the onset of puberty, and therefore an understanding of the synthesis, regulation, and functions of this important androgen pathway warrants attention. Here, we draw attention to the possible modulating influence of DHEA/DHEAS in early brain development from fetal life to the remarkable increase of these steroids in early childhood - the adrenarche. We propose that the pre-pubertal DHEA/DHEAS surge plays a key role in modulating early brain development, perhaps by prolonging brain plasticity during childhood to allow the pre-adolescent brain to adapt and re-wire in response to new, and ever-changing social challenges. Nonetheless, the aetiology of neurodevelopmental phenomena in relation to DHEA/DHEAS synthesis and action cannot be easily studied in humans due to the obvious ethical restrictions on mechanistic studies, the uncertainty of predicting the future mental characteristics of individuals, and the difficulty of conducting retrospective investigations based on pre-birth and/or neonatal complications. We discuss new opportunities for animal studies to resolve these important questions.

G protein-coupled receptor 30 mediates meiosis resumption and gap junction communications downregulation in goat cumulus-oocyte complexes by 17β-estradiol

Estrogen plays a critical role in the regulation of gap junctions between oocytes and granulosa cells in mammalian ovaries. G protein-coupled receptor 30 (GPR30) was identified as a membrane estrogen receptor, mediating rapid, nongenomic signaling events that might be responsible for the regulation of oocyte meiosis resumption and gap junction intercellular communications (GJICs). The present study aimed to determine the expression and localization of GPR30 and its role in oocyte meiotic progression and GJICs in goat cumulus-oocyte complexes (COCs). Immunofluorescence experiments revealed that GPR30 was primarily located in the plasma membrane of cumulus cells and oocytes in goats. 17β-estradiol could promote oocyte meiotic progression, which was blocked by G15 (a selective GPR30 antagonist) but not ICI182780 (a nuclear estrogen receptor inhibitor) in the early stage of in vitro culture. The effect of 17β-estradiol on the GJICs was quantified by lucifer yellow (LY) microinjection and calcein-AM fluorescent dye diffusion. 17β-estradiol treatment of goat COCs resulted in rapid downregulation of GJICs. The transfer of calcein from cumulus cells to oocytes could be significantly inhibited by carbenoxolone (a known gap junction blocker), 17β-estradiol or G1 (a GPR30 agonist), and this inhibition could be reversed by G15 but not ICI182780, indicating that GPR30 mediates the effect of 17β-estradiol on the rapid downregulation of GJICs. 17β-estradiol also stimulated the serine 368 phosphorylation of connexin 43 (Cx43) when COCs were in vitro cultured for 4 h, 6 h, and 8 h. More importantly, 17β-estradiol or G1 could separately promote the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and Cx43 significantly when COCs were cultured for 4 h. Furthermore, both ERK1/2 and Cx43 phosphorylation could be inhibited by G15 and the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478 or by the ERK1/2 inhibitor PD98059, indicating that EGFR-ERK1/2 signaling was involved in these events. These results supported the hypothesis that GPR30 mediated 17β-estradiol-stimulated meiotic resumption and GJIC reduction in goat COCs. Thus, the present study provides novel insights into elucidating the mechanisms for steroid hormone action in the regulation of oocyte maturation.

Synthesis of steroid bisglucuronide and sulfate glucuronide reference materials: Unearthing neglected treasures of steroid metabolism

Doubly or bisconjugated steroid metabolites have long been known as minor components of the steroid profile that have traditionally been studied by laborious and indirect fractionation, hydrolysis and gas chromatography-mass spectrometry (GC-MS) analysis. Recently, the synthesis and characterisation of steroid bis(sulfate) (aka disulfate or bis-sulfate) reference materials enabled the liquid chromatography-tandem mass spectrometry (LC-MS/MS) study of this metabolite class and the development of a constant ion loss (CIL) scan method for the direct and untargeted detection of steroid bis(sulfate) metabolites. Methods for the direct LC-MS/MS detection of other bisconjugated steroids, such as steroid bisglucuronide and mixed steroid sulfate glucuronide metabolites, have great potential to reveal a more complete picture of the steroid profile. However, access to steroid bisglucuronide or sulfate glucuronide reference materials necessary for LC-MS/MS method development, metabolite identification or quantification is severely limited. In this work, ten steroid bisglucuronide and ten steroid sulfate glucuronide reference materials were synthesised through an ordered combination of chemical sulfation and/or enzymatic glucuronylation reactions. All compounds were purified and characterised using NMR and MS methods. Chemistry for the preparation of stable isotope labelled steroid {¹³C₆}-glucuronide internal standards has also been developed and applied to the preparation of two selectively mono-labelled steroid bisglucuronide reference materials used to characterise more completely MS fragmentation pathways. The electrospray ionisation and fragmentation of the bisconjugated steroid reference materials has been studied. Preliminary targeted ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis of the reference materials prepared revealed the presence of three steroid sulfate glucuronides as endogenous human urinary metabolites.

Identification of zebrafish steroid sulfatase and comparative analysis of the enzymatic properties with human steroid sulfatase

Steroid sulfatase (STS) plays an important role in the regulation of steroid hormones. Metabolism of steroid hormones in zebrafish has been investigated, but the action of steroid sulfatase remains unknown. In this study, a zebrafish sts was cloned, expressed, purified, and characterized in comparison with the orthologous human enzyme. Enzymatic assays demonstrated that similar to human STS, zebrafish Sts was most active in catalyzing the hydrolysis of estrone-sulfate and estradiol-sulfate, among five steroid sulfates tested as substrates. Kinetic analyses revealed that the Km values of zebrafish Sts and human STS differed with respective substrates, but the catalytic efficiency as reflected by the Vmax/Km appeared comparable, except for DHEA-sulfate with which zebrafish Sts appeared less efficient. While zebrafish Sts was catalytically active at 28 °C, the enzyme appeared more active at 37 °C and with similar Km values to those determined at 28 °C. Assays performed in the presence of different divalent cations showed that the activities of both zebrafish and human STSs were stimulated by Ca2+, Mg2+, and Mn2+, and inhibited by Zn+2 and Fe2+. EMATE and STX64, two known mammalian steroid sulafatase inhibitors, were shown to be capable of inhibiting the activity of zebrafish Sts. Collectively, the results obtained indicated that zebrafish Sts exhibited enzymatic characteristics comparable to the human STS, suggesting that the physiological function of STS may be conserved between zebrafish and humans.