Role of pregnenolone, dehydroepiandrosterone and their sulfate esters on learning and memory in cognitive aging

Biological characteristics of pregnancy in captive Yangtze finless porpoises revealed by urinary metabolomics†

The Yangtze finless porpoises (Neophocaena asiaeorientalis a.) are an endemic and critically endangered species in China. Intensive captive breeding is essential for understanding the biology of critically endangered species, especially their pregnancy characteristics, knowledge of which is crucial for effective breeding management. Urine metabolomics can reveal metabolic differences, arising from physiological changes across pregnancy stages. Therefore, we used the urinary metabolomic technology, to explore urinary metabolite changes in pregnant Yangtze finless porpoises. A total of 2281 metabolites were identified in all samples, which including organic acids and derivatives (24.45%), organoheterocyclic compounds (20.23%), benzenoids (18.05%), organic oxygen compounds (7.73%), and phenylpropanoids and polyketides (6.48%). There were 164, 387, and 522 metabolites demonstrating differential abundance during early pregnancy, mid pregnancy, and late pregnancy, respectively, from the levels observed in nonpregnancy. The levels of pregnenolone, 17α-hydroxyprogesterone, and tetrahydrocortisone were significantly higher during all pregnancy stages, indicating their important roles in fetal development. The differential metabolites between nonpregnancy and pregnancy were mainly associated with amino acid and carbohydrate metabolism. Moreover, metabolic activity varied across pregnancy stages; steroid hormone biosynthesis was predominant in early pregnancy, and amino acid biosynthesis and carbohydrate metabolism were predominant in mid pregnancy and late pregnancy, respectively. Our results provide new insights into metabolic characteristics in the Yangtze finless porpoises' urine during pregnancy, and indicate that the differential levels of urine metabolites can determine pregnancy in Yangtze finless porpoises, providing valuable information for the husbandry and management of pregnant Yangtze finless porpoises in captivity.

The role of genetic polymorphisms in the sulfation of pregnenolone by human cytosolic sulfotransferase SULT2B1a

Pregnenolone is a key intermediate in the biosynthesis of many steroid hormones and neuroprotective steroids. Sulfotransferase family cytosolic 2B member 1 (SULT2B1a) has been reported to be highly selective to sulfate pregnenolone. This study aimed to clarify the effect of missense single nucleotide polymorphisms (SNPs) of the human SULT2B1 gene on the sulfating activity of coded SULT2B1a allozymes toward Pregnenolone. To investigate the effects of single nucleotide polymorphisms of the SULT2B1 gene on the sulfation of pregnenolone by SULT2B1a allozymes, 13 recombinant SULT2B1a allozymes were generated, expressed, and purified using established procedures. Human SULT2B1a SNPs were identified by a comprehensive database search. 13 SULT2B1a nonsynonymous missense coding SNPs (cSNPs) were selected, and site-directed mutagenesis was used to generate the corresponding cDNAs, packaged in pGEX-2TK expression vector, encoding these 13 SULT2B1a allozymes, which were bacterially expressed in BL21 E. coli cells and purified by glutathione-Sepharose affinity chromatography. Purified SULT2B1a allozymes were analyzed for sulfating activities towards pregnenolone. In comparison with the wild-type SULT2B1a, of the 13 allozymes, 11 showed reduced activity toward pregnenolone at 0.1 µM. Specifically, P134L and R259Q allozymes, reported to be involved in autosomal-recessive congenital ichthyosis, displayed low activity (1-10%) toward pregnenolone. The findings of this study may demonstrate the impact of genetic polymorphism on the sulfation of pregnenolone in individuals with different SULT2B1 genotypes.

Advances in steroid research from the pioneering neurosteroid concept to metabolomics: New insights into pregnenolone function

Advances in neuroendocrinology have led to major discoveries since the 19th century, identifying adaptive loops for maintaining homeostasis. One of the most remarkable discoveries was the concept of neurosteroids, according to which the brain is not only a target but also a source of steroid production. The identification of new membrane steroid targets now underpins the neuromodulatory effects of neurosteroids such as pregnenolone, which is involved in functions mediated by the GPCR CB1 receptor. Structural analysis of steroids is a key feature of their interactions with the phospholipid membrane, receptors and resulting activity. Therefore, mass spectrometry-based methods have been developed to elucidate the metabolic pathways of steroids, the ultimate approach being metabolomics, which allows the identification of a large number of metabolites in a single sample. This approach should enable us to make progress in understanding the role of neurosteroids in the functioning of physiological and pathological processes.

The role of genetic polymorphisms in the sulfation of pregnenolone by human cytosolic sulfotransferase SULT2B1a

Pregnenolone is a key intermediate in the biosynthesis of many steroid hormones and neuroprotective steroids. Sulfotransferase family cytosolic 2B member 1 (SULT2B1a) has been reported to be highly selective to sulfate pregnenolone. This study aimed to clarify the effect of missense single nucleotide polymorphisms (SNPs) of the human SULT2B1 gene on the sulfating activity of coded SULT2B1a allozymes toward Pregnenolone. To investigate the effects of single nucleotide polymorphisms of the SULT2B1 gene on the sulfation of pregnenolone by SULT2B1a allozymes, 13 recombinant SULT2B1a allozymes were generated, expressed, and purified using established procedures. Human SULT2B1a SNPs were identified by a comprehensive database search. 13 SULT2B1a nonsynonymous missense coding SNPs (cSNPs) were selected, and site-directed mutagenesis was used to generate the corresponding cDNAs, packaged in pGEX-2TK expression vector, encoding these 13 SULT2B1a allozymes, which were bacterially expressed in BL21 E. coli cells and purified by glutathione-Sepharose affinity chromatography. Purified SULT2B1a allozymes were analyzed for sulfating activities towards pregnenolone. In comparison with the wild-type SULT2B1a, of the 13 allozymes, 11 showed reduced activity toward pregnenolone at 0.1 μM. Specifically, P134L and R259Q allozymes, reported to be involved in autosomal-recessive congenital ichthyosis, displayed low activity (1-10%) toward pregnenolone. The findings of this study may demonstrate the impact of genetic polymorphism on the sulfation of pregnenolone in individuals with different SULT2B1 genotypes.

Dehydroepiandrosterone (DHEA) increases undirected singing behavior and alters dopaminergic regulation of undirected song in non-breeding male European starlings (Sturnus vulgaris)

Introduction

It has been proposed that in species that defend territories across multiple life history stages, brain metabolism of adrenal dehydroepiandrosterone (DHEA) regulates aggressive behavior at times when gonadal androgen synthesis is low (i.e. the non-breeding season). To date, a role for DHEA in the regulation of other forms of social behavior that are expressed outside of the context of breeding remains unknown.

Methods

In this experiment, we used the European starling (Sturnus vulgaris) model system to investigate a role for DHEA in the neuroendocrine regulation of singing behavior by males in non-breeding condition. Starling song in a non-breeding context is spontaneous, not directed towards conspecifics, and functions to maintain cohesion of overwintering flocks.

Results

Using within-subjects design, we found that DHEA implants significantly increase undirected singing behavior by non-breeding condition male starlings. Given that DHEA is known to modulate multiple neurotransmitter systems including dopamine (DA) and DA regulates undirected song, we subsequently used immunohistochemistry for phosphorylated tyrosine hydroxylase (pTH, the active form of the rate-limiting enzyme in DA synthesis) to investigate the effect of DHEA on dopaminergic regulation of singing behavior in a non-breeding context. Pearson correlation analysis revealed a positive linear association between undirected singing behavior and pTH immunoreactivity in the ventral tegmental area and midbrain central gray of DHEA-implanted, but not control-implanted, males.

Discussion

Taken together, these data suggest that undirected singing behavior by non-breeding starlings is modulated by effects of DHEA on dopaminergic neurotransmission. More broadly, these data expand the social behavior functions of DHEA beyond territorial aggression to include undirected, affiliative social communication.

Neurosteroids as positive and negative allosteric modulators of ligand-gated ion channels: P2X receptor perspective

Neurosteroids are steroids synthesized de novo in the brain from cholesterol in an independent manner from peripheral steroid sources. The term "neuroactive steroid" includes all steroids independent of their origin, and newly synthesized analogs of neurosteroids that modify neuronal activities. In vivo application of neuroactive steroids induces potent anxiolytic, antidepressant, anticonvulsant, sedative, analgesic and amnesic effects, mainly through interaction with the γ-aminobutyric acid type-A receptor (GABA_AR). However, neuroactive steroids also act as positive or negative allosteric regulators on several ligand-gated channels including N-methyl-d-aspartate receptors (NMDARs), nicotinic acetylcholine receptors (nAChRs) and ATP-gated purinergic P2X receptors. Seven different P2X subunits (P2X1-7) can assemble to form homotrimeric or heterotrimeric ion channels permeable for monovalent cations and calcium. Among them, P2X2, P2X4, and P2X7 are the most abundant within the brain and can be regulated by neurosteroids. Transmembrane domains are necessary for neurosteroid binding, however, no generic motif of amino acids can accurately predict the neurosteroid binding site for any of the ligand-gated ion channels including P2X. Here, we will review what is currently known about the modulation of rat and human P2X by neuroactive steroids and the possible structural determinants underlying neurosteroid-induced potentiation and inhibition of the P2X2 and P2X4 receptors.

Age, adrenal steroids, and cognitive functioning in captive chimpanzees (Pan troglodytes)

Background

Dehydroepiandrosterone-sulfate is the most abundant circulating androgen in humans and other catarrhines. It is involved in several biological functions, such as testosterone production, glucocorticoid antagonist actions, neurogenesis and neuroplasticty. Although the role of dehydroepiandrosterone-sulfate (DHEAS) in cognition remains elusive, the DHEAS/cortisol ratio has been positively associated with a slower cognitive age-decline and improved mood in humans. Whether this relationship is found in nonhuman primates remains unknown.

Methods

We measured DHEAS and cortisol levels in serum of 107 adult chimpanzees to investigate the relationship between DHEAS levels and age. A subset of 21 chimpanzees was used to test the potential associations between DHEAS, cortisol, and DHEAS/cortisol ratio in cognitive function, taking into account age, sex, and their interactions. We tested for cognitive function using the primate cognitive test battery (PCTB) and principal component analyses to categorize cognition into three components: spatial relationship tasks, tool use and social communication tasks, and auditory-visual sensory perception tasks.

Results

DHEAS levels, but not the DHEAS/cortisol ratio, declined with age in chimpanzees. Our analyses for spatial relationships tasks revealed a significant, positive correlation with the DHEAS/cortisol ratio. Tool use and social communication had a negative relationship with age. Our data show that the DHEAS/cortisol ratio, but not DHEAS individually, is a promising predictor of spatial cognition in chimpanzees.

Pharmacogenetics of human sulfotransferases and impact of amino acid exchange on Phase II drug metabolism

Sulfotransferases (SULTs) are Phase II drug-metabolizing enzymes (DMEs) catalyzing the sulfation of a variety of endogenous compounds, natural products, and drugs. Various drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDS) can inhibit SULTs, affecting drug-drug interactions. Several polymorphisms have been identified for SULTs that might be crucial for interindividual variability in drug response and toxicity or for increased disease risk. Here, we review current knowledge on non-synonymous single nucleotide polymorphisms (nsSNPs) of human SULTs, focusing on the coded SULT allozymes and molecular mechanisms explaining their variable activity, which is essential for personalized medicine. We discuss the structural and dynamic bases of key amino acid (AA) variants implicated in the impacts on drug metabolism in the case of SULT1A1, as revealed by molecular modeling approaches.

Comparative Assessment of TSPO Modulators on Electroencephalogram Activity and Exploratory Behavior

Network communication in the CNS relies upon multiple neuronal and glial signaling pathways. In addition to synaptic transmission, other organelles such as mitochondria play roles in cellular signaling. One highly conserved mitochondrial signaling mechanism involves the 18 kDa translocator protein (TSPO) of the outer mitochondrial membrane. Originally, TSPO was identified as a binding site for benzodiazepines in the periphery. It was later discovered that TSPO is found in mitochondria, including in CNS cells. TSPO is implicated in multiple cellular processes, including the translocation of cholesterol and steroidogenesis, porphyrin transport, cellular responses to stress, inflammation, and tumor progression. Yet the impacts of modulating TSPO signaling on network activity and behavioral performance have not been characterized. In the present study, we assessed the effects of TSPO modulators PK11195, Ro5-4864, and XBD-173 via electroencephalography (EEG) and the open field test (OFT) at low to moderate doses. Cortical EEG recordings revealed increased power in the δ and θ frequency bands after administration of each of the three modulators, as well as compound- and dose-specific changes in α and γ. Behaviorally, these compounds reduced locomotor activity in the OFT in a dose-dependent manner, with XBD-173 having the subtlest behavioral effects while still strongly modulating the EEG. These findings indicate that TSPO modulators, despite their diversity, exert similar effects on the EEG while displaying a range of sedative/hypnotic effects at moderate to high doses. These findings bring us one step closer to understanding the functions of TSPO in the brain and as a target in CNS disease.

Neuropeptidergic control of neurosteroids biosynthesis

Neurosteroids are steroids synthesized within the central nervous system either from cholesterol or by metabolic reactions of circulating steroid hormone precursors. It has been suggested that neurosteroids exert pleiotropic activities within the central nervous system, such as organization and activation of the central nervous system and behavioral regulation. It is also increasingly becoming clear that neuropeptides exert pleiotropic activities within the central nervous system, such as modulation of neuronal functions and regulation of behavior, besides traditional neuroendocrinological functions. It was hypothesized that some of the physiological functions of neuropeptides acting within the central nervous system may be through the regulation of neurosteroids biosynthesis. Various neuropeptides reviewed in this study possibly regulate neurosteroids biosynthesis by controlling the activities of enzymes that catalyze the production of neurosteroids. It is now required to thoroughly investigate the neuropeptidergic control mechanisms of neurosteroids biosynthesis to characterize the physiological significance of this new neuroendocrinological phenomenon.

The influence of hormonal contraception on depression and female sexuality: a narrative review of the literature

OBJECTIVE

Over the past decades, an increasing number of women have been using hormonal contraception. The potential role of sex hormones in regulating vegetative, psychophysiological, and cognitive functions has been highlighted in several studies, and there is a need to further understand the impact of hormonal contraception on women's quality of life, especially as regards psychological health and sexuality.

METHODS

We conducted a narrative review aimed at clarifying the mechanisms involved in the interaction between sex hormones and the brain, also focusing on the association between hormonal contraception and mood and sexual function.

RESULTS

Our findings clarified that hormonal contraception may be associated with depressive symptoms, especially among adolescents, and with sexual dysfunction. However, the evidence included in this review was conflicting and did not support the hypothesis that hormonal contraception directly causes depressive symptoms, major depressive disorder, or sexual dysfunction.

CONCLUSIONS

The optimal hormonal contraception should be identified in the context of shared decision making, considering the preferences and needs of each woman, as well as her physical and psychosexual conditions.

Therapeutic potential of pregnenolone and pregnenolone methyl ether on depressive and CDKL5 deficiency disorders: Focus on microtubule targeting

Pregnenolone methyl-ether (PME) is a synthetic derivative of the endogenous neuroactive steroid pregnenolone (PREG), which is an important modulator of several brain functions. In addition to being the precursor of steroids, PREG acts directly on various targets including microtubules (MTs), the functioning of which is fundamental for the development and homeostasis of nervous system. The coordination of MT dynamics is supported by a plethora of MT-associated proteins (MAPs) and by a specific MT code that is defined by the post-translational modifications of tubulin. Defects associated with MAPs or tubulin post-translational modifications are linked to different neurological pathologies including mood and neurodevelopmental disorders. In this review, we describe the beneficial effect of PME in major depressive disorders (MDDs) and in CDKL5 deficiency disorder (CDD), two pathologies that are joint by defective MT dynamics. Growing evidence indeed suggests that PME, as well as PREG, is able to positively affect the MT-binding of MAP2 and the plus-end tracking protein CLIP170 that are both found to be deregulated in the above mentioned pathologies. Furthermore, PME influences the state of MT acetylation, the deregulation of which is often associated with neurological abnormalities including MDDs. By contrast to PREG, PME is not metabolised into other downstream molecules with specific biological properties, an aspect that makes this compound more suitable for therapeutic strategies. Thus, through the analysis of MDDs and CDD, this work focuses attention on the possible use of PME for neuronal pathologies associated with MT defects.

Blood Dehydroepiandrosterone and Dehydroepiandrosterone Sulfate as Pathophysiological Correlates of Chronic Pain: Analyses Using a National Sample of Midlife Adults in the United States

OBJECTIVE

Identifying biomarkers is a priority in translational chronic pain research. Dehydroepiandrosterone (DHEA) and its sulfated form, DHEA-S, are adrenocortical steroids in the blood with neuroprotective properties that also produce sex hormones. They may capture key sex-specific neuroendocrine mechanisms of chronic pain.

DESIGN

Cross-sectional study.

METHODS

Using data from 1,216 community-dwelling adults aged 34-84 from the Midlife in the United States (MIDUS) cohort, we examined blood DHEA and DHEA-S levels in association with chronic pain in men and women, adjusting for demographics, chronic diseases, medications including opioids, and psychosocial factors. If an association was found, we further explored dose-response relationships by the number of pain locations and the degree of pain interference.

RESULTS

In women, chronic pain was associated with 0.072 lower (95% confidence interval [CI], -0.127 to -0.017) log10 DHEA-S µg/dL, with pain in one to two locations associated with 0.068 lower (95% CI, -0.131 to -0.006) and in three or more locations 0.071 lower (95% CI, -0.148 to 0.007) log10 DHEA-S (P for trend = 0.074). Furthermore for women, low-interference pain was associated with 0.062 lower (95% CI, -0.125 to -0.000), whereas high-interference pain was associated with 0.138 lower (95% CI, -0.233 to -0.043) log10 DHEA-S (P for trend = 0.004). Chronic pain was not associated with DHEA or DHEA-S levels in men or DHEA levels in women.

CONCLUSIONS

Chronic pain and its functional interference correspond to lower blood DHEA-S levels in women.

Determination of neurosteroids in human cerebrospinal fluid in the 21st century: A review

Determination of steroid hormones synthesized by the human body plays an important role in various fields of endocrinology. Neurosteroids (NS) are steroids that are synthesized in the central (CNS) or peripheral nervous system (PNS), which is not only a source but also a target for neurosteroids. They are discussed as possible biomarkers in various cognitive disorders and research interest in this topic raises continuously. Nevertheless, knowledge on functions and metabolism is still limited, although the concept of neurosteroids was already introduced in the 1980s. Until today, the analysis of neurosteroids is truly challenging. The only accessible matrix for investigations of brain metabolism in living human beings is cerebrospinal fluid (CSF), which therefore becomes a very interesting specimen for analysis. However, neurosteroid concentrations are expected to be very low and the available amount of cerebrospinal fluid is limited. Further, high structural similarities of endogenous neurosteroids challenges analysis. Therefore, comprehensive methods, highly selective and sensitive for a large range of concentrations for different steroids in one aliquot are required and under continuous development. Although research has been increasingly intensified, still only few data are available on reference levels of neurosteroids in human cerebrospinal fluid. In this review, published literature of the last twenty years, as a period with relatively contemporary analytical methods, was systematically investigated. Considerations on human cerebrospinal fluid, different analytical approaches, and available data on levels of in analogy to periphery conceivable occurring neurosteroids, including (pro-) gestagens, androgens, corticoids, estrogens, and steroid conjugates, and their interpretation are intensively discussed.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

Hypothalamic Astrocyte Development and Physiology for Neuroprogesterone Induction of the Luteinizing Hormone Surge

Neural circuits in female rats sequentially exposed to estradiol and progesterone underlie so-called estrogen positive feedback that induce the surge release of pituitary luteinizing hormone (LH) leading to ovulation and luteinization of the corpus hemorrhagicum. It is now well-established that gonadotropin releasing hormone (GnRH) neurons express neither the reproductively critical estrogen receptor-α (ERα) nor classical progesterone receptor (PGR). Estradiol from developing ovarian follicles acts on ERα-expressing kisspeptin neurons in the rostral periventricular region of the third ventricle (RP3V) to induce PGR expression, and kisspeptin release. Circulating estradiol levels that induce positive feedback also induce neuroprogesterone (neuroP) synthesis in hypothalamic astrocytes. This local neuroP acts on kisspeptin neurons that express PGR to augment kisspeptin expression and release needed to stimulate GnRH release, triggering the LH surge. In vitro and in vivo studies demonstrate that neuroP signaling in kisspeptin neurons occurs through membrane PGR activation of Src family kinase (Src). This signaling cascade has been also implicated in PGR signaling in the arcuate nucleus of the hypothalamus, suggesting that Src may be a common mode of membrane PGR signaling. Sexual maturation requires that signaling between neuroP synthesizing astrocytes, kisspeptin and GnRH neurons be established. Prior to puberty, estradiol does not facilitate the synthesis of neuroP in hypothalamic astrocytes. During pubertal development, levels of membrane ERα increase in astrocytes coincident with an increase of PKA phosphorylation needed for neuroP synthesis. Currently, it is not clear whether these developmental changes occur in existing astrocytes or are due to a new population of astrocytes born during puberty. However, strong evidence suggests that it is the former. Blocking new cell addition during puberty attenuates the LH surge. Together these results demonstrate the importance of pubertal maturation involving hypothalamic astrocytes, estradiol-induced neuroP synthesis and membrane-initiated progesterone signaling for the CNS control of ovulation and reproduction.

Improvement of Remyelination in Demyelinated Corpus Callosum Using Human Adipose-Derived Stem Cells (hADSCs) and Pregnenolone in the Cuprizone Rat Model of Multiple Sclerosis

Adipose-derived stem cells (ASCs) have neuroprotective effects, and their repair ability has been approved in neurodegenerative studies. Pregnenolone as a neurosteroid plays significant roles in neurogenesis. We aimed to consider the effect of ADSCs and pregnenolone injection on the multiple sclerosis (MS) model created by cuprizone. Male Wistar rats (n = 36) were fed with an ordinary diet or a diet with cuprizone (0.6%) for 3 weeks. H-ADSCs were taken from patients with lipoaspirate surgery. The rats were divided into six groups (n = 6): healthy, MS, sham, pregnenolone injection, ADSCs injection, pregnenolone and ADSCs injection. Behavioral test, histological examination and TEM were conducted. The specific markers for myelin and cell differentiation were assessed using immunohistochemistry staining. Additionally, the measure of MBP and MOG gene expression and the amount of related proteins were determined using real-time RT-PCR and ELISA techniques, respectively. Histologic results showed that induced demyelination in corpus callosum fibers. TEM revealed an increased thickness of myelin in fibers in the treated groups (P < 0.05). Injection of hADSC and pregnenolone significantly increased the expression levels of MBP and MOG (P < 0.001). The mean percentage of MOG and MBP markers were significantly increased in the treated groups compared to MS and sham groups (P < 0.05). Moreover, the OD level of MBP and MOG proteins showed that their values in the ADSCs/pregnenolone group were close to those of the control group without a significant difference. Our data indicated the remyelination potency and cell differentiation can improve with ADSCs and pregnenolone treatments in the multiple sclerosis model which created by cuprizone in rats.

Effect of SULT2B1 genetic polymorphisms on the sulfation of dehydroepiandrosterone and pregnenolone by SULT2B1b allozymes

Pregnenolone and dehydroepiandrosterone (DHEA) are hydroxysteroids that serve as biosynthetic precursors for steroid hormones in human body. SULT2B1b has been reported to be critically involved in the sulfation of pregnenolone and DHEA, particularly in the sex steroid-responsive tissues. The current study was designed to investigate the impact of the genetic polymorphisms of SULT2B1 on the sulfation of DHEA and pregnenolone by SULT2B1b allozymes. Ten SULT2B1b allozymes previously prepared were shown to exhibit differential sulfating activities toward DHEA and pregnenolone in comparison to the wild-type enzyme. Kinetic studies revealed further significant changes in their substrate-binding affinity and catalytic activity toward DHEA and pregnenolone. Taken together, these results indicated clearly a profound effect of SULT2B1 genetic polymorphisms on the sulfating activity of SULT2B1b allozymes toward DHEA and pregnenolone, which may have implications in inter-individual variations in the homeostasis of these two important steroid precursors.

Spinal Nitric Oxide Synthase Type II Increases Neurosteroid-metabolizing Cytochrome P450c17 Expression in a Rodent Model of Neuropathic Pain

We have previously demonstrated that the neurosteroid dehydroepiandrosterone sulfate (DHEAS) induces functional potentiation of N-methyl-D-aspartate (NMDA) receptors via increases in phosphorylation of NMDA receptor GluN1 subunit (pGluN1). However, the modulatory mechanisms responsible for the expression of the DHEA-synthesizing enzyme, cytochrome P450c17 following peripheral nerve injury have yet to be examined. Here we determined whether oxidative stress induced by the spinal activation of nitric oxide synthase type II (NOS-II) modulates the expression of P450c17 and whether this process contributes to the development of neuropathic pain in rats. Chronic constriction injury (CCI) of the sciatic nerve induced a significant increase in the expression of NOS-II in microglial cells and NO levels in the lumbar spinal cord dorsal horn at postoperative day 5. Intrathecal administration of the NOS-II inhibitor, L-NIL during the induction phase of neuropathic pain (postoperative days 0~5) significantly reduced the CCI-induced development of mechanical allodynia and thermal hyperalgesia. Sciatic nerve injury increased the expression of PKC- and PKA-dependent pGluN1 as well as the mRNA and protein levels of P450c17 in the spinal cord at postoperative day 5, and these increases were suppressed by repeated administration of L-NIL. Co-administration of DHEAS together with L-NIL restored the development of neuropathic pain and pGluN1 that were originally inhibited by L-NIL administration alone. Collectively these results provide strong support for the hypothesis that activation of NOS-II increases the mRNA and protein levels of P450c17 in the spinal cord, ultimately leading to the development of central sensitization and neuropathic pain induced by peripheral nerve injury.

Hormonal Status and Cognitivo-Emotional Profile in Real-Life Patients With Neuropathic Pain: A Case Control Study

BACKGROUND

The specific impact of neuropathic pain and recommended neuropathic pain treatments on the hormonal and immune status of patients has been so far poorly explored. This study aimed at studying, in real life, the hypothalamic-pituitary-adrenal axis and the cytokine profile of patients with neuropathic pain. It also explored their links with cognition, emotion, quality of life, and drug treatment.

METHODS

This prospective study (clinicaltrials.gov NCT01543425) included 60 patients with neuropathic pain and 60 age- and gender-matched healthy volunteers after obtaining signatures of informed consent. A number of parameters were measured: adrenocorticotropic hormone, cortisol, cortisol awakening response, dehydroepiandrosterone sulphate, sex hormone binding globulin, testosterone, 17-β-estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, cytokines, brain-derived neurotrophic factor, and vitamin D. Psychological parameters were assessed by questionnaires.

RESULTS

Patients with neuropathic pain had lower levels of adrenocorticotropic hormone (P = 0.009) and dehydroepiandrosterone sulphate (P < 0.001) than controls, and the cortisol awakening response was impaired. Patients were more depressed and anxious (P < 0.001) and had a diminished quality of life (P < 0.001), which was influenced by cytokines (P = 0.0067) and testosterone (P = 0.028). Antidepressants and antiepileptics appeared to interfere with testosterone and cognitivo-emotional domains.

CONCLUSION

An impairment of the hormonal status and of the immune system was observed in patients. It identified testosterone as a potential pivotal mediator between antidepressants/antiepileptics and quality of life. Further studies must address the exact impact of different types of drugs on central effects, of gender differences, and of the immune system of neuropathic pain.

Effects of defined mixtures of POPs and endocrine disruptors on the steroid metabolome of the human H295R adrenocortical cell line

The presence of environmental pollutants in our ecosystem may impose harmful health effects to wildlife and humans. Several of these toxic chemicals have a potential to interfere with the endocrine system. The adrenal cortex has been identified as the main target organ affected by endocrine disrupting chemicals. The aim of this work was to assess exposure effects of defined and environmentally relevant mixtures of chlorinated, brominated and perfluorinated chemicals on steroidogenesis, using the H295R adrenocortical cell line model in combination with a newly developed liquid chromatography tandem mass spectrometry (LC-MS/MS) method. By using this approach, we could simultaneously analyze 19 of the steroids in the steroid biosynthesis pathway, revealing a deeper insight into possible disruption of steroidogenesis. Our results showed a noticeable down-regulation in steroid production when cells were exposed to the highest concentration of a mixture of brominated and fluorinated compounds (10,000-times human blood values). In contrast, up-regulation was observed with estrone under the same experimental condition, as well as with some other steroids when cells were exposed to a perfluorinated mixture (1000-times human blood values), and the mixture of chlorinated and fluorinated compounds. Interestingly, the low concentration of the perfluorinated mixture alone produced a significant, albeit small, down-regulation of pregnenolone, and the total mixture a similar effect on 17-hydroxypregnenolone. Other mixtures resulted in only slight deviations from the control. Indication of synergistic effects were noted when we used a statistical model to improve data interpretation. A potential for adverse outcomes of human exposures is indicated, pointing to the need for further investigation into these mixtures.

The neurosteroid pregnenolone promotes degradation of key proteins in the innate immune signaling to suppress inflammation

Pregnenolone is a steroid hormone precursor that is synthesized in various steroidogenic tissues, in the brain, and in lymphocytes. In addition to serving as the precursor for other steroid hormones, pregnenolone exerts its own effect as an anti-inflammatory molecule to maintain immune homeostasis in various inflammatory conditions. Pregnenolone and its metabolic derivatives have been shown to have beneficial effects in the brain, including enhancing memory and learning, reversing depressive disorders, and modulating cognitive functions. A decreased level of pregnenolone has been observed in neuroinflammatory diseases, which emphasizes its role in neuroprotection and neuroregeneration. Although the anti-inflammatory property of pregnenolone was recognized several decades ago, its mechanism of action remains unknown. Here we report that pregnenolone promotes ubiquitination and degradation of the TLR2/4 adaptor protein TIRAP and TLR2 in macrophages and microglial cells. Pregnenolone and its metabolites suppressed the secretion of tumor necrosis factor α and interleukin-6 mediated through TLR2 and TLR4 signaling. Pregnenolone has been reported to induce activation of cytoplasmic linker protein 170, and this protein has recently been shown to promote targeted degradation of TIRAP. We observed enhanced degradation of TIRAP and TLR4 suppression by cytoplasmic linker protein 170 in the presence of pregnenolone. Our experimental data reveal novel nongenomic targets of pregnenolone and provide important leads to understand its role in restoring immune homeostasis in various inflammatory conditions.

Physiological changes after spa treatment - a focus on endocrinology

The paper presents the results of our effort to reveal objective parameters for evaluation of the spa treatment for patients with anxiety-depressive disorders. The study was based on our previous experience with neuroactive steroids and neurosteroids, which play a crucial role in the psychological well-being of patients by maintaining balance of the organism. A total number of 94 steroids were determinated in a group of 70 female patients diagnosed with anxiety-depressive disorders. Patients underwent a month spa treatment while maintaining unchanged medication dosing with SSRI (selective serotonin reuptake inhibitors). The other investigated factors contributing to improving the health of treated subjects were amino-acid homocysteine and serotonin. The blood samples were collected at the beginning and the end of the spa treatment. Serotonin in all patients increased by a relative 23 % (results given as relative differences in percent), while homocysteine decreased by 17.1 %. Statistically significant increases were found in 21 steroids, which indicate activation of the adrenal cortex. It can be assumed, that the overall improvement in the mental condition of patients, which was proved by questionnaire from Knobloch and Hausner, the increase in immune suppressive substances and anti-autoimmune responses, will maintain for a longer time after the spa treatment.

Pregnenolone as a potential candidate for hormone therapy for female reproductive disorders targeting ERβ

Many steroid hormones such as estrogen (E2) bind to their receptors for the regulation of biological processes. Pregnenolone (P5) is the precursor form of almost all steroid hormones and is often used to treat skin disorders and neurological complications. However, the mechanism and physiological function of P5 in reproductive organs are not well established. In this study, we investigated the effects of P5 on activation and expression of E2 receptor (ER) in the uteri and ovaries. To study the mechanism of P5 directly, Ishikawa cells were transfected with E2 response element (ERE)-luciferase plasmid and isoforms of ER. ERE-luciferase activity induced by P5 was similar to that induced by E2, and P5 showed high activity for ERβ without any relevance to P5-metabolizing hormones such as progesterone (P4) and E2. In an animal study, immature female rats treated with P5 showed upregulation of ERα and downregulation of ERβ in the uteri, which is the main organ expressing ERα. In ERβ-expressing organ ovaries, estrogen receptor 1, estrogen receptor 2, and P4 receptor were all downregulated by P5 and E2. Also, a decrease of ovarian cell proliferation and viability was observed in response to P5 relative to the control, suggesting that P5 may be a candidate for antiproliferative hormone of ovarian cancer. These findings suggest that P5 stimulates ERE promoter by ERβ-mediated signaling in the uteri and ovaries. Activation of ERβ by P5 may help in understanding the mechanism of ER-related female reproductive diseases such as endometriosis and ovarian cancer.

Neurosteroids in Schizophrenia: Pathogenic and Therapeutic Implications

Neurosteroids are a group of important endogenous molecules affecting many neural functions in the brain. Increasing evidence suggests a possible role of these neurosteroids in the pathology and symptomatology of schizophrenia (SZ) and other mental disorders. The aim of this review is to summarize the current knowledge about the neural functions of neurosteroids in the brain, and to evaluate the role of the key neurosteroids as candidate modulators in the etiology and therapeutics of SZ. The present paper provides a brief introduction of neurosteroid metabolism and distribution, followed by a discussion of the mechanisms underlying neurosteroid actions in the brain. The content regarding the modulation of the GABAA receptor is elaborated, given the considerable knowledge of its interactions with other neurotransmitter and neuroprotective systems, as well as its ameliorating effects on stress that may play a role in the SZ pathophysiology. In addition, several preclinical and clinical studies suggested a therapeutic benefit of neurosteroids in SZ patients, even though the presence of altered neurosteroid pathways in the circulating blood and/or brain remains debatable. Following treatment of antipsychotic drugs in SZ, therapeutic benefits have also been linked to the regulation of neurosteroid signaling. Specifically, the neurosteroids such as pregnenolone and dehydroepiandrosterone affect a broad spectrum of behavioral functions through their unique molecular characteristics and may represent innovative therapeutic targets for SZ. Future investigations in larger cohorts with long-term follow-ups will be required to ascertain the neuropsychopharmacological role of this yet unexploited class of neurosteroid agents.

Uptake and metabolism of sulphated steroids by the blood-brain barrier in the adult male rat

Little is known about the origin of the neuroactive steroids dehydroepiandrosterone sulphate (DHEAS) and pregnenolone sulphate (PregS) in the brain or of their subsequent metabolism. Using rat brain perfusion in situ, we have found ³H‐PregS to enter more rapidly than ³H‐DHEAS and both to undergo extensive (> 50%) desulphation within 0.5 min of uptake. Enzyme activity for the steroid sulphatase catalysing this deconjugation was enriched in the capillary fraction of the blood–brain barrier and its mRNA expressed in cultures of rat brain endothelial cells and astrocytes. Although permeability measurements suggested a net efflux, addition of the efflux inhibitors GF120918 and/or MK571 to the perfusate reduced rather than enhanced the uptake of ³H‐DHEAS and ³H‐PregS; a further reduction was seen upon the addition of unlabelled steroid sulphate, suggesting a saturable uptake transporter. Analysis of brain fractions after 0.5 min perfusion with the ³H‐steroid sulphates showed no further metabolism of PregS beyond the liberation of free steroid pregnenolone. By contrast, DHEAS underwent 17‐hydroxylation to form androstenediol in both the steroid sulphate and the free steroid fractions, with some additional formation of androstenedione in the latter. Our results indicate a gain of free steroid from circulating steroid sulphates as hormone precursors at the blood–brain barrier, with implications for ageing, neurogenesis, neuronal survival, learning and memory.

Adjunctive Pregnenolone Ameliorates the Cognitive Deficits in Recent-Onset Schizophrenia: An 8-Week, Randomized, Double-Blind, Placebo-Controlled Trial

PURPOSE

This study aimed to examine the effect of add-on treatment with the neurosteroid pregnenolone (PREG) on neurocognitive dysfunctions of patients with recent-onset schizophrenia (SZ) and schizoaffective disorder (SA).

METHOD

Sixty out- and inpatients that met DSM-IV criteria for SZ/SA were randomized to an 8-week, double-blind, randomized, placebo-controlled, 2-center trial. Participants received either pregnenolone (50 mg/d) or placebo added on to antipsychotic medications. Computerized Cambridge Automated Neuropsychological Test Battery measures were administered at baseline and after 4 and 8 weeks of treatment. ANOVA and paired t- or z-tests were applied to examine between- and within-group differences over time.

RESULTS

Compared to placebo, adjunctive PREG significantly reduced the deficits in visual attention measured with the Matching to Sample Visual Search task (p=0.002), with moderate effect sizes (d=0.42). In addition, a significant improvement was observed from baseline to end-of-study with respect to the visual (p=0.008) and sustained attention (Rapid Visual Information Processing, p=0.038) deficits, and executive functions (Stockings of Cambridge, p=0.049; Spatial Working Memory, p<0.001) among patients receiving PREG but not among those receiving placebo (all p's>0.05). This beneficial effect of PREG was independent of the type of antipsychotic agents, gender, age, education, and illness duration.

CONCLUSIONS

Pregnenolone augmentation demonstrated significant amelioration of the visual attention deficit in recent-onset SZ/SA. Long-term, large-scale studies are required to obtain greater statistical significance and more confident clinical generalization.

Per- and polyfluoroalkyl substances (PFASs) - New endocrine disruptors in polar bears (Ursus maritimus)?

Per- and polyfluoroalkyl substances (PFASs) are emerging in the Arctic and accumulate in brain tissues of East Greenland (EG) polar bears. In vitro studies have shown that PFASs might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential PFAS induced alterations in brain steroid concentrations. The concentrations of eleven steroid hormones were determined in eight brain regions from ten EG polar bears. Pregnenolone (PRE), the dominant progestagen, was found in mean concentrations of 5-47ng/g (ww) depending on brain region. PRE showed significantly (p<0.01) higher concentrations in female compared to male bears. Dehydroepiandrosterone (DHEA) found in mean concentrations 0.67-4.58ng/g (ww) was the androgen found in highest concentrations. Among the estrogens estrone (E1) showed mean concentrations of 0.90-2.21ng/g (ww) and was the most abundant. Remaining steroid hormones were generally present in concentrations below 2ng/g (ww). Steroid levels in brain tissue could not be explained by steroid levels in plasma. There was however a trend towards increasing estrogen levels in plasma resulting in increasing levels of androgens in brain tissue. Correlative analyses showed positive associations between PFASs and 17α-hydroxypregnenolone (OH-PRE) (e.g. perflouroalkyl sulfonates (∑PFSA): p<0.01, r=0.39; perfluoroalkyl carboxylates (∑PFCA): p<0.01, r=0.61) and PFCA and testosterone (TS) (∑PFCA: p=0.03, r=0.30) across brain regions. Further when investigating correlative associations in specific brain regions significant positive correlations were found between ∑PFCA and several steroid hormones in the occipital lobe. Correlative positive associations between PFCAs and steroids were especially observed for PRE, progesterone (PRO), OH-PRE, DHEA, androstenedione (AN) and testosterone (TS) (all p≤0.01, r≥0.7). The results from the present study generally indicate that an increase in PFASs concentration seems to concur with an increase in steroid hormones of EG polar bears. It is, however, not possible to determine whether alterations in brain steroid concentrations arise from interference with de novo steroid synthesis or via disruption of peripheral steroidogenic tissues mainly in gonads and feedback mechanisms. Steroids are important for brain plasticity and gender specific behavior as well as postnatal development and sexually dimorph brain function. The present work indicates an urgent need for a better mechanistic understanding of how PFASs may affect the endocrine system of polar bears and potentially other mammal species.

Nongenomic actions of neurosteroid pregnenolone and its metabolites

Steroids have been widely used in the clinical setting. They bind and activate nuclear receptors to regulate gene expression. In addition to activating genomic transcription, steroids also exert nongenomic actions. The current article focuses on the nongenomic actions of neurosteroids, including pregnenolone (P5), 7α-hydroxypregnenolone, pregnenolone sulfate and allopregnanolone. Pregnenolone and its derivatives promote neuronal activity by enhancing learning and memory, relieving depression, enhancing locomotor activity, and promoting neuronal cell survival. They exert these effects by activating various target proteins located in the cytoplasm or cell membrane. Pregnenolone and its metabolites bind to receptors such as microtubule-associated proteins and neurotransmitter receptors to elicit a series of reactions including stabilization of microtubules, increase of ion flux into cells, and dopamine release. The wide actions of neurosteroids indicate that pregnenolone derivatives have great potential in future treatment of neurological diseases.

Naturally occurring marine steroid 24-methylenecholestane-3β,5α,6β,19-tetraol functions as a novel neuroprotectant

Steroids have been shown to have multiple effects on the nervous system including neuroprotective activities, and they have the potential to be used for the treatment of neurodegenerative diseases. In this current study, we tested the hypothesis that the marine steroid 24-methylenecholestane-3β,5α,6β,19-tetraol (Tetrol) has a neuroprotective effect. (1) We synthesized Tetrol through a multiple step reaction starting from hyodeoxycholic acid (HDCA). (2) We then evaluated the neuroprotective effect of Tetrol with a glutamate-induced neuronal injury model in vitro. Tetrol concentration dependently increased the survival rate of cerebellar granule neurons challenged with toxic concentration of glutamate. Consistently, Tetrol significantly decreased glutamate-induced lactate dehydrogenase (LDH) release with a threshold concentration of 2.5 μM. (3) We further evaluated the neuroprotective effect of Tetrol in a middle cerebral artery occlusion (MCAO)-induced cerebral ischemia model in rat. Tetrol, at a dose of 12 mg/kg, significantly decreased MCAO-induced infarction volume by ∼50%. (4) Finally, we probed the mechanism and found that Tetrol concentration dependently attenuated N-methyl-d-aspartate (NMDA)-induced intracellular calcium ([Ca(2+)]i) increase with an IC50 of 7.8±0.62 μM, and inhibited NMDA currents in cortical neurons with an IC50 of 10.28±0.71 μM. Taken together, we have synthesized and characterized Tetrol as a novel neuroprotectant through negative modulation of NMDA receptors.

Neuroplasticity in the maternal hippocampus: Relation to cognition and effects of repeated stress

This article is part of a Special Issue "Parental Care". It is becoming clear that the female brain has an inherent plasticity that is expressed during reproduction. The changes that occur benefit the offspring, which in turn secures the survival of the mother's genetic legacy. Thus, the onset of maternal motivation involves basic mechanisms from genetic expression profiles, to hormone release, to hormone-neuron interactions, all of which fundamentally change the neural architecture - and for a period of time that extends, interestingly, beyond the reproductive life of the female. Although multiple brain areas involved in maternal responses are discussed, this review focuses primarily on plasticity in the maternal hippocampus during pregnancy, the postpartum period and well into aging as it pertains to changes in cognition. In addition, the effects of prolonged and repeated stress on these dynamic responses are considered. The maternal brain is a marvel of directed change, extending into behaviors both obvious (infant-directed) and less obvious (predation, cognition). In sum, the far-reaching effects of reproduction on the female nervous system provide an opportunity to investigate neuroplasticity and behavioral flexibility in a natural mammalian model.

Endogenous 24S-hydroxycholesterol modulates NMDAR-mediated function in hippocampal slices

N-methyl-D-aspartate receptors (NMDARs), a major subtype of glutamate receptors mediating excitatory transmission throughout the central nervous system (CNS), play critical roles in governing brain function and cognition. Because NMDAR dysfunction contributes to the etiology of neurological and psychiatric disorders including stroke and schizophrenia, NMDAR modulators are potential drug candidates. Our group recently demonstrated that the major brain cholesterol metabolite, 24S-hydroxycholesterol (24S-HC), positively modulates NMDARs when exogenously administered. Here, we studied whether endogenous 24S-HC regulates NMDAR activity in hippocampal slices. In CYP46A1(-/-) (knockout; KO) slices where endogenous 24S-HC is greatly reduced, NMDAR tone, measured as NMDAR-to-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) excitatory postsynaptic current (EPSC) ratio, was reduced. This difference translated into more NMDAR-driven spiking in wild-type (WT) slices compared with KO slices. Application of SGE-301, a 24S-HC analog, had comparable potentiating effects on NMDAR EPSCs in both WT and KO slices, suggesting that endogenous 24S-HC does not saturate its NMDAR modulatory site in ex vivo slices. KO slices did not differ from WT slices in either spontaneous neurotransmission or in neuronal intrinsic excitability, and exhibited LTP indistinguishable from WT slices. However, KO slices exhibited higher resistance to persistent NMDAR-dependent depression of synaptic transmission induced by oxygen-glucose deprivation (OGD), an effect restored by SGE-301. Together, our results suggest that loss of positive NMDAR tone does not elicit compensatory changes in excitability or transmission, but it protects transmission against NMDAR-mediated dysfunction. We expect that manipulating this endogenous NMDAR modulator may offer new treatment strategies for neuropsychiatric dysfunction.

Dehydroepiandrosterone Attenuates Cocaine-Seeking Behaviour Independently of Corticosterone Fluctuations

The neurosteroid dehydroepiandrosterone (DHEA) is involved in the pathophysiology of several psychiatric disorders, including cocaine addiction. We have previously shown that DHEA attenuates cocaine-seeking behaviour, and also that DHEA decreases corticosterone (CORT) levels in plasma and the prefrontal cortex. Previous studies have found that rats demonstrate cocaine-seeking behaviour only when the level of CORT reaches a minimum threshold. In the present study, we investigated whether the attenuating effect of DHEA on cocaine seeking is a result of it reducing CORT levels rather than a result of any unique neurosteroid properties. Rats received either daily DHEA injections (2 mg/kg, i.p.) alone, daily DHEA (2 mg/kg, i.p.) with CORT infusion (to maintain stable basal levels of CORT; 15 mg/kg, s.c.) or vehicle (i.p.) as control, throughout self-administration training and extinction sessions. We found that both DHEA-treated and DHEA + CORT-treated groups showed a significantly lower number of active lever presses compared to controls throughout training and extinction sessions, as well as at cocaine-primed reinstatement. DHEA-treated rats showed lower CORT levels throughout the experimental phases compared to DHEA + CORT-treated and control rats. Additionally, we show that DHEA administered to cocaine-trained rats throughout extinction sessions, or immediately before reinstatement, attenuated cocaine seeking. These findings indicate that DHEA attenuates cocaine-seeking behaviour independently of fluctuations in CORT levels.

Analytical challenges for measuring steroid responses to stress, neurodegeneration and injury in the central nervous system

Levels of steroids in the adult central nervous system (CNS) show marked changes in response to stress, degenerative disorders and injury. However, their analysis in complex matrices such as fatty brain and spinal cord tissues, and even in plasma, requires accurate and precise analytical methods. Radioimmunoassays (RIA) and enzyme-linked immunosorbent assays, even with prepurification steps, do not provide sufficient specificity, and they are at the origin of many inconsistent results in the literature. The analysis of steroids by mass spectrometric methods has become the gold standard for accurate and sensitive steroid analysis. However, these technologies involve multiple purification steps prone to errors, and they only provide accurate reference values when combined with careful sample workup. In addition, the interpretation of changes in CNS steroid levels is not an easy task because of their multiple sources: the endocrine glands and the local synthesis by neural cells. In the CNS, decreased steroid levels may reflect alterations of their biosynthesis, as observed in the case of chronic stress, post-traumatic stress disorders or depressive episodes. In such cases, return to normalization by administering exogenous hormones or by stimulating their endogenous production may have beneficial effects. On the other hand, increases in CNS steroids in response to acute stress, degenerative processes or injury may be part of endogenous protective or rescue programs, contributing to the resistance of neural cells to stress and insults. The aim of this review is to encourage a more critical reading of the literature reporting steroid measures, and to draw attention to the absolute need for well-validated methods. We discuss reported findings concerning changing steroid levels in the nervous system by insisting on methodological issues. An important message is that even recent mass spectrometric methods have their limits, and they only become reliable tools if combined with careful sample preparation.

Ontogenetic Change in the Regional Distribution of Dehydroepiandrosterone-Synthesizing Enzyme and the Glucocorticoid Receptor in the Brain of the Spiny Mouse (Acomys cahirinus)

The androgen dehydroepiandrosterone (DHEA) has trophic and anti-glucocorticoid actions on brain growth. The adrenal gland of the spiny mouse (Acomys cahirinus) synthesizes DHEA. The aim of this study was to determine whether the brain of this precocial species is also able to produce DHEA de novo during fetal, neonatal and adult life. The expression of P450c17 and cytochrome b5 (Cytb5), the enzyme and accessory protein responsible for the synthesis of DHEA, was determined in fetal, neonatal and adult brains by immunocytochemistry, and P450c17 bioactivity was determined by the conversion of pregnenolone to DHEA. Homogenates of fetal brain produced significantly more DHEA after 48 h in culture (22.46 ± 2.0 ng/mg tissue) than adult brain homogenates (5.04 ± 2.0 ng/mg tissue; p < 0.0001). P450c17 and Cytb5 were co-expressed in fetal neurons but predominantly in oligodendrocytes and white matter tracts in the adult brain. Because DHEA modulates glucocorticoids actions, the expression of the glucocorticoid receptor (GR) was also determined. In the brainstem, medulla, midbrain, and cerebellum, the predominant GR localization changed from neurons in the fetal brain to oligodendrocytes and white matter tracts in the adult brain. The change of expression of P450c17, Cytb5 and GR proteins with cell type, brain region and developmental age indicates that DHEA is an endogenous neurosteroid in this species that may have important trophic and stress-modifying actions during both prenatal and postnatal life.

Reduced Sulfotransferase SULT2A1 Activity in Patients With Alzheimer´s Disease

Steroids are important components in the pathophysiology of Alzheimer’s disease (AD). Although their role has been studied, the corresponding metabolomic data is limited. In the present study we evaluate the role of steroid sulfotransferase SULT2A1 in the pathophysiology of AD on the basis of circulating steroids (measured by GC-MS), in which the sulfation catalyzed by SULT2A1 dominates over glucuronidation (pregnenolone/sulfate, DHEA/sulfate, androstenediol/sulfate and 5α-reduced pregnane and androstane catabolites). To estimate a general trend of SUL2A1 activity in AD patients we compared the ratios of steroid conjugates to their unconjugated counterparts (C/U) in controls (11 men and 22 women) and AD patients (18 men and 16 women) for individual circulating steroids after adjustment for age and BMI using ANCOVA model including the factors AD status and gender. Decreased C/U ratio for the C19 steroids demonstrate an association between attenuated sulfation of C19 steroids in adrenal zona reticularis and the pathophysiology of AD.

Characterization of a Synthetic Steroid 24-keto-cholest-5-en-3β, 19-diol as a Neuroprotectant

BACKGROUND

Neuroactive steroids represent promising candidates for the treatment of neurological disorders. Our previous studies identified an endogenous steroid cholestane-3β, 5α, 6β-triol (Triol) as a novel neuroprotectant.

AIM

We aimed to identify a potent candidate for stroke treatment through a screening of Triol analogs.

METHODS

Hypoxia- and glutamate-induced neuronal injury models in vitro, middle cerebral artery occlusion (MCAO)-induced cerebral ischemia model in vivo, fluorescein diacetate (FDA) for alive and propidium iodide (PI) for dead staining, LDH assay, and calcium imaging techniques were used.

RESULTS

24-keto-cholest-5-en-3β, 19-diol (Diol) showed the most potent neuroprotective effect among the screened structurally related compounds. FDA and PI staining showed that Diol concentration dependently increased the survival rate of cerebellar granule neurons (CGNs) challenged with glutamate or hypoxia, with an effective threshold concentration of 2.5 μM. Consistently, the quantitative LDH release assay showed the same concentration-dependent protection in both models. Diol, at 10 μM, potently decreased glutamate- and hypoxia-induced LDH release from 51.6 to 18.2% and 62.1 to 21.7%, respectively, which values are close to the normal LDH release (~16-18%). Moreover, we found Diol effectively decreased MCAO-induced infarction volume in mice from ~23% to 7%, at a dose of 6 mg/kg. We further explored the underlying mechanism and found that Diol attenuated NMDA-induced intracellular calcium ([Ca(2+) ]i ) increase in cortical neurons, suggesting a negative modulatory effect on NMDA receptor.

CONCLUSION

Taken together, we identified Diol as a potent neuroprotectant. It may represent a novel and promising neuroprotectant for stroke intervention.

Dehydroepiandrosterone: a neuroactive steroid

Dehydroepiandrosterone (DHEA) and its sulfate bound form (DHEAS) are important steroids of mainly adrenal origin. They are produced also in gonads and in the brain. Dehydroepiandrosterone easily crosses the brain-blood barrier and in part is also produced locally in the brain tissue. In the brain, DHEA exerts its effects after conversion to either testosterone and dihydrotestosterone or estradiol via androgen and estrogen receptors present in the most parts of the human brain, through mainly non-genomic mechanisms, or eventually indirectly via the effects of its metabolites formed locally in the brain. As a neuroactive hormone, DHEA in co-operation with other hormones and transmitters significantly affects some aspects of human mood, and modifies some features of human emotions and behavior. It has been reported that its administration can increase feelings of well-being and is useful in ameliorating atypical depressive disorders. It has neuroprotective and antiglucocorticoid activity and modifies immune reactions, and some authors have also reported its role in degenerative brain diseases. Here we present a short overview of the possible actions of dehydroepiandrosterone and its sulfate in the brain, calling attention to various mechanisms of their action as neurosteroids and to prospects for the knowledge of their role in brain disorders.

Neuroprotection by the synthetic neurosteroid enantiomers ent-PREGS and ent-DHEAS against Aβ₂₅₋₃₅ peptide-induced toxicity in vitro and in vivo in mice

RATIONALE

Pregnenolone sulfate (PREGS) and dehydroepiandrosterone sulphate (DHEAS) are pro-amnesic, anti-amnesic and neuroprotective steroids in rodents. In Alzheimer's disease (AD) patient's brains, their low concentrations are correlated with high levels of Aβ and tau proteins. The unnatural enantiomer ent-PREGS enhanced memory in rodents. We investigated here whether ent-PREGS and ent-DHEAS could be neuroprotective in AD models.

OBJECTIVE

The effects of PREGS, ent-PREGS, DHEAS and ent-DHEAS against Aβ25-35 peptide-induced toxicity were examined in vitro on B104 neuroblastoma cells and in vivo in mice.

METHODS

B104 cells pretreated with the steroids before Aβ25-35 were analysed by flow cytometry measuring cell viability and death processes. Mice injected intracerebroventricularly with Aβ25-35 and the steroids were analysed for their memory abilities. Additionally, lipid peroxidation levels in the hippocampus were measured.

RESULTS

ent-PREGS and PREGS significantly attenuated the Aβ25-35-induced decrease in cell viability. Both steroids prevented the Aβ25-35-induced increase in late apoptotic cells. PREGS further attenuated the ratio of necrotic cells. ent-DHEAS and DHEAS significantly reduced the Aβ25-35-induced toxicity and prevented the cells from entering late apoptosis and necrosis. All steroids stimulated neurite outgrowth per se and prevented the Aβ25-35-induced decrease. In vivo, ent-PREGS and ent-DHEAS significantly attenuated the Aβ25-35-induced decrease in memory (spontaneous alternation and passive avoidance) and an increase in lipid peroxidation levels. In contrast to the natural steroids, both enantiomers prevented amnesia when injected 6 h before Aβ25-35 in contrast to the natural steroids.

CONCLUSION

The unnatural steroids ent-PREGS and ent-DHEAS are potent neuroprotective agents and could be effective therapeutical tools in AD.

Proof-of-concept randomized controlled trial of pregnenolone in schizophrenia

RATIONALE

Preclinical and clinical data suggest that pregnenolone may be a promising therapeutic in schizophrenia. Pregnenolone is neuroprotective and enhances learning and memory, myelination, and microtubule polymerization. Treatment with pregnenolone elevates allopregnanolone (a neurosteroid that enhances GABAA receptor responses) and pregnenolone sulfate (a positive NMDA receptor modulator). Pregnenolone could thus potentially mitigate GABA dysregulation and/or NMDA receptor hypofunction in schizophrenia via metabolism to other neurosteroids.

OBJECTIVE

The objective of this study is to conduct a randomized controlled trial of adjunctive pregnenolone in schizophrenia.

METHODS

Following a placebo lead-in, 120 participants were randomized to pregnenolone or placebo for 8 weeks (Institute for Mental Health, Singapore). Primary endpoints were changes in MATRICS Consensus Cognitive Battery (MCCB) composite scores (cognitive symptoms), UCSD Performance-based Skills Assessment-Brief (UPSA-B) composite scores (functional capacity), and Scale for Assessment of Negative Symptoms (SANS) total scores (negative symptoms). A modified intent-to-treat analysis approach was utilized.

RESULTS

No significant changes compared to placebo were demonstrated in composite MCCB scores. In contrast, participants randomized to pregnenolone (n = 56) demonstrated greater improvements in functional capacity (UPSA-B composite changes) compared to placebo (n = 55), p = 0.03. Pregnenolone was also superior to placebo in the communication subscale of the UPSA-B (p < 0.001). Serum pregnenolone changes post-treatment were correlated with UPSA-B composite score changes in females (r s = 0.497, p < 0.042, n = 17) but not in males. Mean total SANS scores were very low at baseline and did not improve further post-treatment. Pregnenolone was well-tolerated.

CONCLUSIONS

Pregnenolone improved functional capacity in participants with schizophrenia, but did not improve cognitive symptoms over an 8-week treatment period. Neurosteroid changes correlated with functional improvements in female participants. Neurosteroid interventions may exhibit promise as new therapeutic leads for schizophrenia.

Exogenous dehydroisoandrosterone sulfate reverses the dendritic changes of the central neurons in aging male rats

Sex hormones are known to help maintaining the cognitive ability in male and female rats. Hypogonadism results in the reduction of the dendritic spines of central neurons which is believed to undermine memory and cognition and cause fatigue and poor concentration. In our previous studies, we have reported age-related regression in dendrite arbors along with loss of dendritic spines in the primary somatosensory cortical neurons in female rats. Furthermore, castration caused a reduction of dendritic spines in adult male rats. In light of this, it was surmised that dendritic structures might change in normal aging male rats with advancing age. Recently, dehydroepiandrosterone sulfate (DHEAS) has been reported to have memory-enhancing properties in aged rodents. In this study, normal aging male rats, with a reduced plasma testosterone level of 75-80%, were used to explore the changes in behavioral performance of neuronal dendritic arbor and spine density. Aging rats performed poorer in spatial learning memory (Morris water maze). Concomitantly, these rats showed regressed dendritic arbors and spine loss on the primary somatosensory cortical and hippocampal CA1 pyramidal neurons. Exogenous DHEAS and testosterone treatment reversed the behavioral deficits and partially restored the spine loss of cortical neurons in aging male rats but had no effects on the dendritic arbor shrinkage of the affected neurons. It is concluded therefore that DHEAS, has the efficacy as testosterone, and that it can exert its effects on the central neuron level to effectively ameliorate aging symptoms.