Showing papers on "Pregnenolone published in 2011"
TL;DR: The crystal structure of the complex of human Adx and CYP11A1 is presented—the first of a complex between a eukaryotic CYP and its redox partner and suggests that after an initial protein–protein association driven by electrostatic forces, the complex adopts an optimized geometry between the redox centers.
Abstract: In humans, the precursor to all steroid hormones, pregnenolone, is synthesized from cholesterol by an enzyme complex comprising adrenodoxin reductase (AdR), adrenodoxin (Adx), and a cytochrome P450 (P450scc or CYP11A1). This complex not only plays a key role in steroidogenesis, but also has long been a model to study electron transfer, multistep catalysis, and C-C bond cleavage performed by monooxygenases. Detailed mechanistic understanding of these processes has been hindered by a lack of structural information. Here we present the crystal structure of the complex of human Adx and CYP11A1--the first of a complex between a eukaryotic CYP and its redox partner. The structures with substrate and a series of reaction intermediates allow us to define the mechanism underlying sequential hydroxylations of the cholesterol and suggest the mechanism of C-C bond cleavage. In the complex the [2Fe-2S] cluster of Adx is positioned 17.4 A away from the heme iron of CYP11A1. This structure suggests that after an initial protein-protein association driven by electrostatic forces, the complex adopts an optimized geometry between the redox centers. Conservation of the interaction interface suggests that this mechanism is common for all mitochondrial P450s.
252 citations
TL;DR: Data show that BPA targets the estradiol biosynthesis pathway in the ovary, and pregnenolone was unable to protect follicles from BPA induced inhibition of steroidogenic enzymes compared with the DMSO control.
155 citations
TL;DR: Many endocrine disruptors act as antiandrogens via directly inhibiting one or more enzymes for testosterone biosynthesis and metabolic activation, including industrial materials and pesticides/biocides and plant constituents.
Abstract: The Leydig cells of the testis have the capacity to biosynthesize testosterone from cholesterol. Testosterone and its metabolically activated product dihydrotestosterone are critical for the development of male reproductive system and spermatogenesis. At least four steroidogenic enzymes are involved in testosterone biosynthesis: Cholesterol side chain cleavage enzyme (CYP11A1) for the conversion of cholesterol into pregnenolone within the mitochondria, 3β-hydroxysteroid dehydrogenase (HSD3B), for the conversion of pregnenolone into progesterone, 17α-hydroxylase/17,20-lyase (CYP17A1) for the conversion of progesterone into androstenedione and 17β-hydroxysteroid dehydrogenase (HSD17B3) for the formation of testosterone from androstenedione. Testosterone is also metabolically activated into more potent androgen dihydrotestosterone by two isoforms 5α-reductase 1 (SRD5A1) and 2 (SRD5A2) in Leydig cells and peripheral tissues. Many endocrine disruptors act as antiandrogens via directly inhibiting one or more enzymes for testosterone biosynthesis and metabolic activation. These chemicals include industrial materials (perfluoroalkyl compounds, phthalates, bisphenol A and benzophenone) and pesticides/biocides (methoxychlor, organotins, 1,2-dibromo-3-chloropropane and prochloraz) and plant constituents (genistein and gossypol). This paper reviews these endocrine disruptors targeting steroidogenic enzymes.
134 citations
TL;DR: Pregnenolone is a neurosteroid with pleiotropic actions in rodents that include the enhancement of learning and memory, neuritic outgrowth, and myelination that also increases neurogenesis, decreases apoptosis and inflammation and the mitigation of GABA dysregulation.
130 citations
TL;DR: Antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs) or mirtazapine apparently have an impact on key enzymes of neurosteroidogenesis and have been shown to normalize the disequilibrium of neuroactive steroids in depression by increasing 3α-reduced pregnane steroids and decreasing 3β,5α-tetrahydroprogesterone.
124 citations
TL;DR: In the present review, the current information on CYP17 is analyzed and discussed.
96 citations
TL;DR: The development, optimization and validation of a methodology to determine nine key steroid hormones expressed in the steroidogenesis in biological fluids and the accuracy was 50–112% in the range 0.10 to 2.00 ng/mL.
Abstract: This paper presents the development, optimization and validation of a methodology to determine nine key steroid hormones (viz. pregnenolone, progesterone, dehydroepiandrosterone, androstenedione, testosterone, dihydrotestosterone, estrone, 17α-estradiol and 17β-estradiol) expressed in the steroidogenesis in biological fluids. The analytical method allows for the determination of steroid hormones in blood plasma and serum down to 0.08-0.16 ng/mL for estrogens, 0.20-0.36 ng/mL for androgens and 0.36-0.43 ng/mL for progestagens. These limits of detection were obtainable using a two-step solid-phase clean-up for fractionation and elimination of interfering lipids (fatty acids, phospholipids, glycerides and sterols) from the steroid hormones. The accuracy of the method was 50-112% in the range 0.10 to 2.00 ng/mL.
94 citations
TL;DR: It is demonstrated by high‐performance liquid chromatography that the zebrafish brain has the ability to convert [3H]‐pregnenolone into a variety of radiolabeled steroids, and messengers for key steroidogenic enzymes, such as Cyp11a1 (P450SCC), 3β‐Hsd, Cyp17 and Cyp19a1b, are widely expressed in the forebrain where they exhibit an overall similar pattern.
Abstract: The brain of adult teleost fish exhibits several unique and interesting features, notably an intense neurogenic activity linked to persistence of radial glial cells acting as neural progenitors, and a high aromatase activity supported by strong expression of the cyp19a1b gene Strikingly, cyp19a1b expression is restricted to radial glial cells, suggesting that estrogens are able to modulate their activity This raises the question of the origin, central or peripheral, of C19 androgens available for aromatization This study aimed to investigate the activity and expression of other main steroidogenic enzymes in the brain of adult zebrafish We demonstrate by high-performance liquid chromatography that the zebrafish brain has the ability to convert [³H]-pregnenolone into a variety of radiolabeled steroids such as 17OH-pregnenolone, dehydroepiandrosterone, androstenedione, testosterone, dihydro-testosterone, estrone, estradiol, progesterone, and dihydro- and tetrahydro-progesterone Next, we show by in situ hybridization that messengers for key steroidogenic enzymes, such as Cyp11a1 (P450(SCC)), 3β-Hsd, Cyp17 and Cyp19a1b, are widely expressed in the forebrain where they exhibit an overall similar pattern By combining aromatase B immunohistochemistry with in situ hybridization, we show that cyp11a1, 3β-hsd and cyp17 messengers are found in part in aromatase B-positive radial processes, suggesting mRNA export This set of results provides the first demonstration that the brain of fish can produce true neurosteroids, possibly in radial glial cells Given that radial glial cells are brain stem cells during the entire lifespan of fish, it is suggested that at least some of these neurosteroids are implicated in the persisting neurogenic process
89 citations
TL;DR: Primary human keratinocytes (PHK) are capable of extra-adrenal cortisol synthesis, which could be a fundamental pathway in skin biology with implications in psoriasis and atopic dermatitis.
84 citations
TL;DR: Brain synthesis may provide minimal level of neurosteroids, which are indispensable for the CNS functions, but substantial part of the steroid metabolites may be also synthesized in the CNS from the steroid precursors or directly transported through BBB from the periphery.
67 citations
TL;DR: Pregenolone sulfate induces a signaling cascade in insulinoma cells that is very similar to the signaling cascade induced by glucose in β-cells, and is linked to enhanced expression of the zinc finger transcription factor Egr-1 and EGr-1-responsive target genes.
TL;DR: Transient receptor potential canonical 5 (TRPC5) channels are widely expressed, including in the CNS, where they potentiate fear responses, and whether TRPC5 exhibited sensitivity to steroids was investigated.
Abstract: BACKGROUND AND PURPOSE
Transient receptor potential canonical 5 (TRPC5) channels are widely expressed, including in the CNS, where they potentiate fear responses. They also contribute to other non-selective cation channels that are stimulated by G-protein-coupled receptor agonists and lipid and redox factors. Steroids are known to modulate fear and anxiety states, and we therefore investigated whether TRPC5 exhibited sensitivity to steroids.
TL;DR: Findings from clinical studies have revealed that PREG, DHEA, and their sulfates might be involved in the pathophysiology of schizophrenia, and in some of its manifestations.
TL;DR: The furanyl bearing enone 8, and its pyrazoline derivative 48 were identified as the most active compounds in all derivatives of pregnenolone, which increased the cytotoxicity of all compounds significantly.
TL;DR: This article showed that 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2) formed a transient association with the translocases Tim50 and Tom22 and with Tim23.
TL;DR: Extended in vivo treatment with testosterone decreased the expression of Scarb1 (scavenger receptor class B type 1), Tspo (translocator protein), Star (steroidogenic acute regulatory protein), Cyp11a1 (cholesterol side-chain cleavage enzyme), and Cyp17a1
TL;DR: The potential of Fusarium oxysporum var.
TL;DR: An efficient and facile synthesis of 17-chalconyl derivatives of pregnenolone and their evaluation as antimicrobial agents against various microbial strains is reported.
TL;DR: These results imply the complete pathway of corticosteroid synthesis of ‘pregnenolone →PROG→DOC→CORT’ in the hippocampal neurons and may play a role in modulation of synaptic plasticity, in contrast to the stress effects by micromolar CORT from adrenal glands.
Abstract: Background: Brain synthesis of steroids including sex-steroids is attracting much attention. The endogenous synthesis of corticosteroids in the hippocampus, however, has been doubted because of the inability to detect deoxycorticosterone (DOC) synthase, cytochrome P450(c21). Methodology/Principal Findings: The expression of P450(c21) was demonstrated using mRNA analysis and immmunogold electron microscopic analysis in the adult male rat hippocampus. DOC production from progesterone (PROG) was demonstrated by metabolism analysis of 3 H-steroids. All the enzymes required for corticosteroid synthesis including P450(c21), P450(2D4), P450(11b1) and 3b-hydroxysteroid dehydrogenase (3b-HSD) were localized in the hippocampal principal neurons as shown via in situ hybridization and immunoelectron microscopic analysis. Accurate corticosteroid concentrations in rat hippocampus were determined by liquid chromatography-tandem mass spectrometry. In adrenalectomized rats, net hippocampus-synthesized corticosterone (CORT) and DOC were determined to 6.9 and 5.8 nM, respectively. Enhanced spinogenesis was observed in the hippocampus following application of low nanomolar (10 nM) doses of CORT for 1 h. Conclusions/Significance: These results imply the complete pathway of corticosteroid synthesis of ‘pregnenolone RPROGRDOCRCORT’ in the hippocampal neurons. Both P450(c21) and P450(2D4) can catalyze conversion of PROG to DOC. The low nanomolar level of CORT synthesized in hippocampal neurons may play a role in modulation of synaptic plasticity, in contrast to the stress effects by micromolar CORT from adrenal glands.
TL;DR: Pharmacological and genetic experiments revealed that both L-type Ca2+ channels and transient receptor potential melastatin 3 (TRPM3) channels are essential for connecting pregnenolone sulfate stimulation with enhanced AP-1 activity and bZIP-mediated transcription in insulinoma cells.
Abstract: The neurosteroid pregnenolone sulfate activates a signaling cascade in insulinoma cells involving activation of extracellular signal-regulated protein kinase and enhanced expression of the transcription factor Egr-1. Here, we show that pregnenolone sulfate stimulation leads to a significant elevation of activator protein-1 (AP-1) activity in insulinoma cells. Expression of the basic region leucine zipper (bZIP) transcription factors c-Jun and c-Fos is up-regulated in insulinoma cells and pancreatic β-cells in primary culture after pregnenolone sulfate stimulation. Up-regulation of a chromatin-embedded c-Jun promoter/luciferase reporter gene transcription in pregnenolone sulfate-stimulated insulinoma cells was impaired when the AP-1 binding sites were mutated, indicating that these motifs function as pregnenolone sulfate response elements. In addition, phosphorylation of cAMP response element (CRE)-binding protein is induced and transcription of a CRE-controlled reporter gene is stimulated after pregnenolone sulfate treatment, indicating that the CRE functions as a pregnenolone sulfate response element as well. Pharmacological and genetic experiments revealed that both L-type Ca(2+) channels and transient receptor potential melastatin 3 (TRPM3) channels are essential for connecting pregnenolone sulfate stimulation with enhanced AP-1 activity and bZIP-mediated transcription in insulinoma cells. In contrast, pregnenolone sulfate stimulation did not enhance AP-1 activity or c-Jun and c-Fos expression in pituitary corticotrophs that express functional L-type Ca(2+) channels but only trace amounts of TRPM3. We conclude that expression of L-type Ca(2+) channels is not sufficient to activate bZIP-mediated gene transcription by pregnenolone sulfate. Rather, additional expression of TRPM3 or depolarization of the cells is required to connect pregnenolone sulfate stimulation with enhanced gene transcription.
TL;DR: The results suggest that glutamate release at CF-to-PC synapses is an important target of PregS in the neonatal cerebellar cortex, an effect that may play a role in the refinement of these synapses.
TL;DR: The formation and metabolism of neurosteroids from cholesterol is now known to occur in the brain of birds, and it is recently found that the quail brain expresses cytochrome P4507α and produces 7α- and 7β-hydroxypregnenolone, previously undescribed avian neurosteroid, from pregnenolones.
Abstract: It is now established that the brain and other nervous systems have the capability of forming steroids de novo, the so-called “neurosteroids” The pioneering discovery of Baulieu and his colleagues, using rodents, has opened the door to a new research field of "neurosteroids" In contrast to mammalian vertebrates, little has been known regarding de novo neurosteroidogenesis in the brain of birds We therefore investigated neurosteroid formation and metabolism in the brain of quail, a domestic bird Our studies over the past two decades demonstrated that the quail brain possesses cytochrome P450 side-chain cleavage enzyme (P450scc), 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3beta-HSD), 5beta-reductase, cytochrome P450 17alpha-hydroxylase/c17,20-lyase (P45017alpha,lyase), 17beta-HSD, etc, and produces pregnenolone, progesterone, 5beta-dihydroprogesterone (5beta-DHP), 3beta, 5beta-tetrahydroprogesterone (3beta, 5beta-THP), androstenedione, testosterone, and estradiol from cholesterol Independently, Schlinger's laboratory demonstrated that the brain of zebra finch, a songbird, also produces various neurosteroids Thus, the formation and metabolism of neurosteroids from cholesterol is now known to occur in the brain of birds In addition, we recently found that the quail brain expresses cytochrome P4507alpha and produces 7alpha-and 7beta-hydroxypregnenolone, previously undescribed avian neurosteroids, from pregnenolone This paper summarizes the advances made in our understanding of neurosteroid formation and metabolism in the brain of domestic birds This paper also describes what are currently known about physiological changes in neurosteroid formation and biological functions of neurosteroids in the brain of domestic and other birds
TL;DR: In this article, the effects of PS on NMDAR function are diverse, varying with subunit composition and NR1 splice variant, and additional tuning of the PS response by PS comes via the N-terminal exon-5 splicing insert of NR1-1b, which regulates the magnitude of proton-dependent PS potentiation.
Abstract: NMDA receptor (NMDAR)-mediated excitatory synaptic transmission plays a critical role in synaptic plasticity and memory formation, whereas its dysfunction may underlie neuropsychiatric and neurodegenerative diseases. The neuroactive steroid pregnenolone sulfate (PS) acts as a cognitive enhancer in impaired animals, augments LTP in hippocampal slices by enhancing NMDAR activity, and may participate in the reduction of schizophrenia's negative symptoms by systemic pregnenolone. We report that the effects of PS on NMDAR function are diverse, varying with subunit composition and NR1 splice variant. While PS potentiates NR1-1a/NR2B receptors through a critical steroid modulatory domain in NR2B that also modulates tonic proton inhibition, potentiation of the NMDA response is not dependent upon relief of such inhibition, a finding that distinguishes it from spermine. In contrast, the presence of an NR2A subunit confers enhanced PS-potentiation at reduced pH, suggesting that it may indeed act like spermine does at NR2B-containing receptors. Additional tuning of the NMDAR response by PS comes via the N-terminal exon-5 splicing insert of NR1-1b, which regulates the magnitude of proton-dependent PS potentiation. For NR2C- and NR2D-containing receptors, negative modulation at NR2C receptors is pH-independent (like NR2B) while negative modulation at NR2D receptors is pH-dependent (like NR2A). Taken together, PS displays a rich modulatory repertoire that takes advantage of the structural diversity of NMDARs in the CNS. The differential pH sensitivity of NMDAR isoforms to PS modulation may be especially important given the emerging role of proton sensors to both learning and memory, as well as brain injury.
TL;DR: The results imply that Mamld1 enhances Cyp17a1 expression primarily in Leydig cells and permit to produce a sufficient amount of testosterone for male sex development, independently of the Hes3-related non-canonical Notch signaling.
Abstract: Background
MAMLD1 is known to be a causative gene for hypospadias. Although previous studies have indicated that MAMLD1 mutations result in hypospadias primarily because of compromised testosterone production around the critical period for fetal sex development, the underlying mechanism(s) remains to be clarified. Furthermore, although functional studies have indicated a transactivation function of MAMLD1 for the non-canonical Notch target Hes3, its relevance to testosterone production remains unknown. To examine these matters, we performed Mamld1 knockdown experiments.
Methodology/Principal Findings
Mamld1 knockdown was performed with two siRNAs, using mouse Leydig tumor cells (MLTCs). Mamld1 knockdown did not influence the concentrations of pregnenolone and progesterone but significantly reduced those of 17-OH pregnenolone, 17-OH progesterone, dehydroepiandrosterone, androstenedione, and testosterone in the culture media. Furthermore, Mamld1 knockdown significantly decreased Cyp17a1 expression, but did not affect expressions of other genes involved in testosterone biosynthesis as well as in insulin-like 3 production. Hes3 expression was not significantly altered. In addition, while 47 genes were significantly up-regulated (fold change >2.0×) and 38 genes were significantly down-regulated (fold change <0.5×), none of them was known to be involved in testosterone production. Cell proliferation analysis revealed no evidence for compromised proliferation of siRNA-transfected MLTCs.
Conclusions/Significance
The results, in conjunction with the previous data, imply that Mamld1 enhances Cyp17a1 expression primarily in Leydig cells and permit to produce a sufficient amount of testosterone for male sex development, independently of the Hes3-related non-canonical Notch signaling.
TL;DR: JOHANNESSON, T. eC.
Abstract: JOHANNESSON, T. eC. WOODS, L. A. (1964). KAYMAKCALAN, S. & WOODS, L. A. (1956). LOH, H. H., SHE^, F. H. & WAY, E. L. (1969). SMITHS, S. E. & TAKEMORI, A. E. (1968). TIRRI, R. (1967). UNGAR, G. & COHEN, M. (1966). Br. J. Pharmac., 38, 157-170. In Scientific basis of drug dependence, Editor: Steinberg, H., pp. 77-86. London: J. and A. Churchill Ltd. Acta pharmac. tox., 21, 381-396. J. Pharmac. exp. Ther., 117, 112-116.
Patent•
28 Mar 2011TL;DR: In this paper, the modified neuroactive steroids can be used to treat, prevent and/or ameliorate a phenotypic state of interest in a subject, such as hypertension.
Abstract: The present disclosure provides modified neuroactive steroids. The modified neuroactive steroids may comprise, consist of, or consist essentially of a therapeutic agent and/or a modifying moiety. The modified neuroactive steroid can have modified characteristics as compared to native neuroactive steroids that do not include a modifying moiety and/or therapeutic agent. The modified neuroactive steroid may be, for example, modified pregnenolone, pregnenolone metabolites, allopregnanolone, and/or allopregnanolone metabolites. The modified neuroactive steroids can be used to treat, prevent and/or ameliorating a phenotypic state of interest in a subject.
TL;DR: In this paper, ammonium perfluorooctanoate (APFO) at doses of 0, 1.0, or 5.0 mg/kg/day was administered to 129/sv wild-type (mPPARα), Pparα -null and PPARα-humanized ( hPPAR α ) mice for 6 weeks.
TL;DR: It is suggested that low concentrations of PBDE-710 could stimulate testosterone secretion by acting directly on Leydig cells to activate the cAMP pathway and increase expression of StAR.
Abstract: background: Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants that have been defined as major environmental pollutants. While previous studies have found that PBDEs may enhance the levels of sex-steroid hormones, their effects on testosterone secretion from rat Leydig cells are unclear. This study investigated the effects and mechanisms of PBDE-710, a mixture of tetra- and penta-PBDEs, on testosterone biosynthesis in rat Leydig cells. methods: Leydig cells from adult male rats were challenged with different concentrations of PBDE-710 (0.5 –15 ng/ml) to evaluate the effects on testosterone steroidogenesis. Concentrations of testosterone and of cAMP and pregnenolone in medium were measured by radioimmunoassay (RIA) and by enzyme-linked immunosorbent assay, respectively. Nuclear translocation of protein kinase A a (PKAa )w as determined by immunofluorence assay and western blot assay, and the mRNA expression of steroidogenic acute regulatory protein (StAR) was analyzed by quantitative real-time polymerase chain reaction. results: In this in vitro study, PBDE-710 (5 or 15 ng/ml) increased basal testosterone secretion and cAMP production by 3- and 2-fold, respectively. The stimulatory effect was abolished by adenylyl cyclase inhibitor. Enzyme activity of CYP11A1, as determined by the pregnenolone concentration, was stimulated by PBDE-710 treatment. Furthermore, nuclear translocation of PKAa was increased by 20% and StAR gene expression was elevated by 4-fold after PBDE-710 treatment. conclusions: These results suggest that low concentrations of PBDE-710 could stimulate testosterone secretion by acting directly on Leydig cells to activate the cAMP pathway and increase expression of StAR.
TL;DR: Sulfonation of cholesterol, oxysterols, and neurosteroids in the brain is apparently catalyzed by SULT2B1b since expression of neither Sult2A1 nor SULT1E1 was detected in human brain sections, which suggests a role for regulation of sterol metabolism by LXR and SULT 2B 1b.
Abstract: Steroid sulfonation in the human brain has not been well characterized. The major sulfotransferase (SULT) isoforms that conjugate steroids in humans are SULT1E1, SULT2A1, and SULT2B1b. SULT2B1b catalyzes the sulfonation of 3β-hydroxysteroids, including neurosteroids dehydroepiandrosterone and pregnenolone, as well as cholesterol and several hydroxycholesterols. SULT2B1b mRNA and protein expression were detected in adult and fetal human brain sections, whereas neither mRNA, nor protein expression were identified for SULT1E1 or SULT2A1. Using immunohistochemical analysis, SULT2B1b expression was detected in neurons and oligodendrocytes in adult brain and in epithelial tissues in 28-week-old fetal brain. Sulfonation of cholesterol, oxysterols, and neurosteroids in the brain is apparently catalyzed by SULT2B1b since expression of neither SULT2A1 nor SULT1E1 was detected in human brain sections. SULT2B1b mRNA and protein were also detected in human U373-MG glioblastoma cells. Both mRNA and protein expression of liver X receptor (LXR)-β, but not LXR-α, were detected in U373-MG cells, and LXR-β activation resulted in a decrease in SULT2B1b protein expression. Since hydroxycholesterols are important physiological LXR activators, this suggests a role for regulation of sterol metabolism by LXR and SULT2B1b. Therefore, elucidating key enzymes in the metabolism of cholesterol and neurosteroids could help define the properties of steroid conjugation in the human brain.
TL;DR: The data accumulated over the past two decades demonstrate that discrete populations of neurons and/or glial cells in the frog and newt brains express the major steroidogenic enzymes and are able to synthesize de novo a number of neurosteroids from cholesterol/pregnenolone.
Abstract: Amphibians have been widely used to investigate the synthesis of biologically active steroids in the brain and the regulation of neurosteroid production by neurotransmitters and neuropeptides. The aim of the present review is to summarize the current knowledge regarding the neuroanatomical distribution and biochemical activity of steroidogenic enzymes in the brain of anurans and urodeles. The data accumulated over the past two decades demonstrate that discrete populations of neurons and/or glial cells in the frog and newt brains express the major steroidogenic enzymes and are able to synthesize de novo a number of neurosteroids from cholesterol/pregnenolone. Since neurosteroidogenesis has been conserved during evolution from amphibians to mammals, it appears that neurosteroids must play important physiological functions in the central nervous system of vertebrates