Steroid sulfatase in the human MG-63 preosteoblastic cell line: Antagonistic regulation by glucocorticoids and NFκB

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.

Estrogen sulfotransferase and sulfatase in steroid homeostasis, metabolic disease, and cancer

Sulfation and desulfation of steroids are opposing processes that regulate the activation, metabolism, excretion, and storage of steroids, which account for steroid homeostasis. Steroid sulfation and desulfation are catalyzed by cytosolic sulfotransferase and steroid sulfatase, respectively. By modifying and regulating steroids, cytosolic sulfotransferase (SULT) and steroid sulfatase (STS) are also involved in the pathophysiology of steroid-related diseases, such as hormonal dysregulation, metabolic disease, and cancer. The estrogen sulfotransferase (EST, or SULT1E1) is a typical member of the steroid SULTs. This review is aimed to summarize the roles of SULT1E1 and STS in steroid homeostasis and steroid-related diseases.

New structural insights provide a different angle on steroid sulfatase action

A central part of human sulfation pathways is the spatially and temporally controlled desulfation of biologically highly potent steroid hormones. The responsible enzyme - steroid sulfatase (STS) - is highly expressed in placenta and peripheral tissues, such as fat, colon, and the brain. The shape of this enzyme and its mechanism are probably unique in biochemistry. STS was believed to be a transmembrane protein, spanning the Golgi double-membrane by stem region formed by two extended internal alpha-helices. New crystallographic data however challenge this view. STS now is portraited as a trimeric membrane-associated complex. We discuss the impact of these results on STS function and sulfation pathways in general and we hypothesis that this new STS structural understanding suggests product inhibition to be a regulator of STS enzymatic activity.

The phytochemical curcumin inhibits steroid sulfatase activity in rat liver tissue and NIH-3T3 mouse fibroblast cells

Curcumin is a phytochemical derived from the spice turmeric that is reported to have therapeutic effects. We are studying the enzyme steroid sulfatase (STS), which removes the sulfate group from inactive steroid hormones in peripheral tissues and we were interested in the effect of curcumin on STS activity due to its structural composition (polyphenolic). We sought to determine if curcumin affects STS activity in two model systems, rat liver and NIH-3T3 mouse fibroblast cells. STS assays were performed on tissue extracts of rat liver, and on NIH-3T3 microsomes and cells, with and without curcumin. Male and female rat liver extracts contained substantial amounts of STS activity, with males averaging higher (4-11 %) levels. Estradiol inhibited STS activity in livers of both sexes at 20 and 10 µM. Curcumin acted as a competitive inhibitor of STS activity in rat liver extracts, with a Ki of 19.8 µM in males and 9.3 µM in females. Curcumin also inhibited STS activity in NIH-3T3 microsomes at both 20 µM and 10 µM, and in whole NIH-3T3 cells at 20 µM. These data are the first to demonstrate STS inhibition by curcumin. Inhibition of STS results in lower active steroid hormone (estrogens and androgens) levels in tissues, possibly altering modulation of immune responses by these steroids.

Steroid sulfatase in the mouse NIH-3T3 fibroblast cell line: Characterization, and downregulation by glucocorticoids

Steroid hormones often circulate in the blood 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. We have previously characterized STS activity in human and mouse breast and bone tissues, and we have shown that STS can provide estrogens to these tissues from circulating sulfated precursors. This study was designed to characterize STS activity in a mouse fibroblast cell line (NIH-3T3). Using a radioactive estrone sulfate (E1S) conversion assay, we detected STS activity in cultured NIH-3T3 cells. This activity was blocked by the STS inhibitors EMATE and STX-64, indicating authentic STS activity. We also found that microsomes prepared from NIH-3T3 cells had relatively high STS activity and that cytosols had low activity, consistent with the known distribution of this enzyme to the endoplasmic reticulum. Michaelis-Menten analysis of the NIH-3T3 microsomes indicated a Km of 10.9 µM using E1S as substrate. Primary fibroblasts prepared from mouse ears and tails also had measurable STS activity, as indicated by 3H-E1S conversion assay, further supporting the conclusion that fibroblasts possess STS. Furthermore, Western blotting confirmed the presence of immunoreactive STS in NIH-3T3 microsomes. With regard to regulation, treatments of cultured NIH-3T3 cells revealed that cortisol and the synthetic glucocorticoids dexamethasone and prednisolone decreased STS activity, as we have found for cell lines from other tissues. The effect of cortisol was seen at both 10 µM and 1.0 µM but not at 0.1 µM. Western blotting also indicated a decrease in STS immunoreactivity in cortisol-treated microsomes. The reduction in STS activity by dexamethasone in whole cells was reversed by the glucocorticoid receptor antagonist RU-486, indicating that glucocorticoid downregulation of STS activity is receptor mediated. An inhibition assay on NIH-3T3 microsomes revealed that STS activity was inhibited significantly by 10 µM estradiol-17β, a known substrate inhibitor of E1S for STS, but not by 10 µM cortisol. This is consistent with the idea that cortisol inhibits STS in NIH-3T3 cells through a regulatory mechanism rather than by substrate inhibition. Our results could have important implications regarding local estrogen production by STS in fibroblasts, which are the most common connective tissue cells in the body, and on possible regulation of local estrogen levels by cortisol.

Extremely preterm infant with persistent peeling skin: X-linked ichthyosis imitates prematurity

Objectives

X-linked ichthyosis (XLI) is a genetic disorder caused by a deficiency in steroid sulfatase, an enzyme which catalyzes a reaction in estrone synthesis. The disorder primarily manifests as dry, scaly skin which may be difficult to diagnose in extremely preterm infants, as the dermatological features may be falsely attributed to a normal variant of skin for this population.

Case presentation

In this case report, we describe a male with XLI, born at 24 weeks gestation, who had persistent dry, flaky and hyperpigmented skin. This case is notable for the age of diagnosis in an extremely premature infant; day of life 105. In addition, this infant experienced out of proportion bronchopulmonary symptoms that we postulate may be linked to the steroid sulfatase deficiency, as estrogen is a mediator of surfactant production.

Conclusions

This report underscores the need to potentially evaluate persistent dry, flaky skin in the preterm infant, as XLI may also impact long term neurodevelopmental outcomes.

Diet-derived fruit and vegetable metabolites show sex-specific inverse relationships to osteoporosis status

BACKGROUND

The impact of nutrition on the metabolic profile of osteoporosis (OS) is unknown.

OBJECTIVE

Identify biochemical factors driving the association of fruit and vegetable (FV) intakes with OS prevalence using an untargeted metabolomics approach.

DESIGN

Cross-sectional dietary, anthropometric and plasma metabolite data were examined from the Boston Puerto Rican Osteoporosis Study, n = 600 (46-79 yr).

METHODS

Bone mineral density was assessed by DXA. OS was defined by clinical standards. A culturally adapted FFQ assessed usual dietary intake. Principal components analysis (PCA) of 42 FV items created 6 factors. Metabolomic profiles derived from plasma samples were assessed on a commercial platform. Differences in levels of 525 plasma metabolites between disease groups (OS vs no-OS) were compared using logistic regression; and associations with FV intakes by multivariable linear regression, adjusted for covariates. Metabolites significantly associated with OS status or with total FV intake were analyzed for enrichment in various biological pathways using Mbrole 2.0, MetaboAnalyst, and Reactome, using FDR correction of P-values. Correlation coefficients were calculated as Spearman's rho rank correlations, followed by hierarchical clustering of the resulting correlation coefficients using PCA FV factors and sex-specific sets of OS-associated metabolites.

RESULTS

High FV intake was inversely related to OS prevalence (Odds Ratio = 0.73; 95% CI = 0.57, 0.94; P = 0.01). Several biological processes affiliated with the FV-associating metabolites, including caffeine metabolism, carnitines and fatty acids, and glycerophospholipids. Important processes identified with OS-associated metabolites were steroid hormone biosynthesis in women and branched-chain amino acid metabolism in men. Factors derived from PCA were correlated with the OS-associated metabolites, with high intake of dark leafy greens and berries/melons appearing protective in both sexes.

CONCLUSIONS

These data warrant investigation into whether increasing intakes of dark leafy greens, berries and melons causally affect bone turnover and BMD among middle-aged and older adults at risk for osteoporosis via sex-specific metabolic pathways, and how gene-diet interactions alter these sex-specific metabolomic-osteoporosis links. ClinicalTrials.gov Identifier: NCT01231958.

Shaoyao-Gancao Decoction alleviated hyperandrogenism in a letrozole-induced rat model of polycystic ovary syndrome by inhibition of NF-κB activation

Shaoyao-Gancao Decoction (SGD) has been widely used for the treatment of gynopathy. The present study aimed to evaluate the therapeutic effect and potential mechanism of SGD on hyperandrogenism in polycystic ovary syndrome (PCOS) rats. In the present work, SGD was orally administrated to the PCOS rats at the dose of 12.5, 25, and 50 g/kg/d for 14 consecutive days. UPLC–MS/MS was performed to identify the main chemical components of SGD. Body weight, ovarian weight, cystic dilating follicles, and serum levels of steroid hormones were tested to evaluate the therapeutic effect of SGD. In order to further clarify the underlying mechanism, we also measured mRNA and the protein levels of NF-κB, NF-κB p65, P-NF-κB p65, and IκB by RT-qPCR and Western blotting techniques. Our results showed that SGD treatment significantly alleviated hyperandrogenism in PCOS rats as evidenced by reduced serum levels of T and increased E₂ and FSH levels. In addition, SGD effectively reduced the phosphorylation of NF-κB p65 and increased the expression of IκB. Results of the present study demonstrated that SGD could ameliorate hyperandrogenism in PCOS rats, and the potential mechanism may relate to the NF-κB pathway.

Detection of a novel, primate-specific 'kill switch' tumor suppression mechanism that may fundamentally control cancer risk in humans: an unexpected twist in the basic biology of TP53

The activation of TP53 is well known to exert tumor suppressive effects. We have detected a primate-specific adrenal androgen-mediated tumor suppression system in which circulating DHEAS is converted to DHEA specifically in cells in which TP53 has been inactivated DHEA is an uncompetitive inhibitor of glucose-6-phosphate dehydrogenase (G6PD), an enzyme indispensable for maintaining reactive oxygen species within limits survivable by the cell. Uncompetitive inhibition is otherwise unknown in natural systems because it becomes irreversible in the presence of high concentrations of substrate and inhibitor. In addition to primate-specific circulating DHEAS, a unique, primate-specific sequence motif that disables an activating regulatory site in the glucose-6-phosphatase (G6PC) promoter was also required to enable function of this previously unrecognized tumor suppression system. In human somatic cells, loss of TP53 thus triggers activation of DHEAS transport proteins and steroid sulfatase, which converts circulating DHEAS into intracellular DHEA, and hexokinase which increases glucose-6-phosphate substrate concentration. The triggering of these enzymes in the TP53-affected cell combines with the primate-specific G6PC promoter sequence motif that enables G6P substrate accumulation, driving uncompetitive inhibition of G6PD to irreversibility and ROS-mediated cell death. By this catastrophic 'kill switch' mechanism, TP53 mutations are effectively prevented from initiating tumorigenesis in the somatic cells of humans, the primate with the highest peak levels of circulating DHEAS. TP53 mutations in human tumors therefore represent fossils of kill switch failure resulting from an age-related decline in circulating DHEAS, a potentially reversible artifact of hominid evolution.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

SULFATION PATHWAYS: The steroid sulfate axis and its relationship to maternal behaviour and mental health

Steroid hormones can exist in functionally dissociable sulfated and non-sulfated (free) forms and can exert profound effects on numerous aspects of mammalian physiology; the ratio of free-to-sulfated steroids is governed by the antagonistic actions of steroid sulfatase (STS) and sulfotransferase (SULT) enzymes. Here, I examine evidence from human and animal model studies, which suggests that STS and its major substrate (dehydroepiandrosterone sulfate, DHEAS) and product (DHEA) can influence brain function, behaviour and mental health, before summarising how the activity of this axis varies throughout mammalian pregnancy and the postpartum period. I then consider how the steroid sulfate axis might impact upon normal maternal behaviour and how its dysfunction might contribute towards risk of postpartum psychiatric illness. Understanding the biological substrates underlying normal and abnormal maternal behaviour will be important for maximising the wellbeing of new mothers and their offspring.

SULFATION PATHWAYS: Insights into steroid sulfation and desulfation pathways

Sulfation and desulfation pathways represent highly dynamic ways of shuttling, repressing and re-activating steroid hormones, thus controlling their immense biological potency at the very heart of endocrinology. This theme currently experiences growing research interest from various sides, including, but not limited to, novel insights about phospho-adenosine-5'-phosphosulfate synthase and sulfotransferase function and regulation, novel analytics for steroid conjugate detection and quantification. Within this review, we will also define how sulfation pathways are ripe for drug development strategies, which have translational potential to treat a number of conditions, including chronic inflammatory diseases and steroid-dependent cancers.

Solanum paniculatum L. decreases levels of inflammatory cytokines by reducing NFKB, TBET and GATA3 gene expression in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum paniculatum L., popularly known as jurubeba, is a common subtropical plant from Brazil, Paraguay, Bolivia and Argentina, that is used in folk medicine for the treatment of anemia, gastrointestinal disorders and inflammatory conditions in general. In addition to that, an ethnobotanical survey in "Todos os Santos" Bay have pointed out S. paniculatum as an herb to treat asthma. Previous publications have shown that S. paniculatum possesses antibiotic, antioxidant and modulatory effects on gastric acid secretion; however, its anti-inflammatory potential remains unexplored.

AIM OF THE STUDY

Herein, we analyzed the S. paniculatum fruits hexane extract (SpE) for the presence of stigmasterol and β-sitosterol and investigated the anti-inflammatory effect of SpE in vitro.

MATERIALS AND METHODS

SpE was subjected to high-performance liquid chromatography (HPLC) for standardization and quantification of stigmasterol and β-sitosterol. Spleen cells from BALB/c mice were cultivated and stimulated with pokeweed mitogen and also exposed to 15, 30 and 60µg/mL of SpE. Following treatment, levels of IFN-γ, IL-4 and IL-10 in the culture supernatants were assessed by ELISA. We also evaluated nitric oxide (NO) production by murine LPS-stimulated peritoneal macrophages using the Griess technique. In addition, the ability of SpE to stabilize membranes was assessed using a model of hemolysis induced by heat on murine erythrocytes. Gene expression of Th1-cell-specific Tbx21 transcription factor (TBET), zinc-finger transcription factor-3 (GATA3), and nuclear factor-κB (NFKB) in murine spleen cells were assessed by quantitative Polymerase Chain Reaction (qRT-PCR).

RESULTS

SpE at 15, 30 and 60µg/mL significantly attenuated cell proliferation, decreased IL-4 release, reduced NO production and improved erythrocyte membrane stabilization in a concentration-dependent manner. SpE was also able to decrease the release of IFN-γ without altering IL-10 levels. The mechanism whereby SpE decreased inflammatory markers may be related to the reduction of NFKB, TBET and GATA3 gene expression.

CONCLUSIONS

This study is the first to test the anti-inflammatory action of S. paniculatum. Herein, we provided evidence for the popular use of S. paniculatum in inflammatory conditions. Additional studies must be conducted to further explore the anti-inflammatory potential of SpE and to elucidate possible clinical applications.