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Mortensen M, Bright DP, Fagotti J, Dorovykh V, Cerna B, Smart TG. Forty Years Searching for Neurosteroid Binding Sites on GABA A Receptors. Neuroscience 2024:S0306-4522(24)00257-4. [PMID: 38852898 DOI: 10.1016/j.neuroscience.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/11/2024]
Abstract
Brain inhibition is a vital process for controlling and sculpting the excitability of the central nervous system in healthy individuals. This level of control is provided over several timescales and involves the neurotransmitter GABA acting at inhibitory synapses to: rapidly inhibit neurons by activating the GABAA receptor; over a slower timescale, to tonically activate extrasynaptic GABAA receptors to provide a low level of background inhibition; and finally, to activate G-protein coupled GABAB receptors to control transmitter release by inhibiting presynaptic Ca2+ channels whilst providing postsynaptic inhibition via K+ channel activation. From this plethora of roles for GABA and its receptors, the GABAA receptor isoform is of major interest due to its dynamic functional plasticity, which in part, is due to being targeted by modulatory brain neurosteroids derived from sex and stress hormones. This family of neurosteroids can, depending on their structure, potentiate, activate and also inhibit the activity of GABAA receptors to affect brain inhibition. This review tracks the methods that have been deployed in probing GABAA receptors, and charts the sterling efforts made by several groups to locate the key neurosteroid binding sites that affect these important receptors. Increasing our knowledge of these binding sites will greatly facilitate our understanding of the physiological roles of neurosteroids and will help to advance their use as novel therapeutics to combat debilitating brain diseases.
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Affiliation(s)
- Martin Mortensen
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom
| | - Damian P Bright
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom
| | - Juliane Fagotti
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom
| | - Valentina Dorovykh
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom
| | - Barbora Cerna
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom
| | - Trevor G Smart
- University College London, Dept Neuroscience, Physiology & Pharmacology, Gower Street, London WC1E 6BT, United Kingdom.
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2
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Salvatore SV, Ilagan MXG, Shu H, Lambert PM, Benz A, Qian M, Covey DF, Zorumski CF, Mennerick S. Neuroactive steroid effects on autophagy in a human embryonic kidney 293 (HEK) cell model. Sci Rep 2024; 14:1042. [PMID: 38200205 PMCID: PMC10781668 DOI: 10.1038/s41598-024-51582-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 01/07/2024] [Indexed: 01/12/2024] Open
Abstract
Neuropsychiatric and neurodegenerative disorders are correlated with cellular stress. Macroautophagy (autophagy) may represent an important protective pathway to maintain cellular homeostasis and functionality, as it targets cytoplasmic components to lysosomes for degradation and recycling. Given recent evidence that some novel psychiatric treatments, such as the neuroactive steroid (NAS) allopregnanolone (AlloP, brexanolone), may induce autophagy, we stably transfected human embryonic kidney 293 (HEK) cells with a ratiometric fluorescent probe to assay NAS effects on autophagy. We hypothesized that NAS may modulate autophagy in part by the ability of uncharged NAS to readily permeate membranes. Microscopy revealed a weak effect of AlloP on autophagic flux compared with the positive control treatment of Torin1. In high-throughput microplate experiments, we found that autophagy induction was more robust in early passages of HEK cells. Despite limiting studies to early passages for maximum sensitivity, a range of NAS structures failed to reliably induce autophagy or interact with Torin1 or starvation effects. To probe NAS in a system where AlloP effects have been shown previously, we surveyed astrocytes and again saw minimal autophagy induction by AlloP. Combined with other published results, our results suggest that NAS may modulate autophagy in a cell-specific or context-specific manner. Although there is merit to cell lines as a screening tool, future studies may require assaying NAS in cells from brain regions involved in neuropsychiatric disorders.
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Affiliation(s)
- Sofia V Salvatore
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Ma Xenia G Ilagan
- High-Throughput Screening Core, Center for Drug Discovery, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Hongjin Shu
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Peter M Lambert
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
- Medical Scientist Training Program, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Ann Benz
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Mingxing Qian
- Developmental Biology, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Douglas F Covey
- Developmental Biology, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Charles F Zorumski
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA
| | - Steven Mennerick
- Departments of Psychiatry, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA.
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., MSC 8134-0181-0G, St. Louis, MO, 63110, USA.
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3
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Maguire JL, Mennerick S. Neurosteroids: mechanistic considerations and clinical prospects. Neuropsychopharmacology 2024; 49:73-82. [PMID: 37369775 PMCID: PMC10700537 DOI: 10.1038/s41386-023-01626-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/15/2023] [Accepted: 05/17/2023] [Indexed: 06/29/2023]
Abstract
Like other classes of treatments described in this issue's section, neuroactive steroids have been studied for decades but have risen as a new class of rapid-acting, durable antidepressants with a distinct mechanism of action from previous antidepressant treatments and from other compounds covered in this issue. Neuroactive steroids are natural derivatives of progesterone but are proving effective as exogenous treatments. The best understood mechanism is that of positive allosteric modulation of GABAA receptors, where subunit selectivity may promote their profile of action. Mechanistically, there is some reason to think that neuroactive steroids may separate themselves from liabilities of other GABA modulators, although research is ongoing. It is also possible that intracellular targets, including inflammatory pathways, may be relevant to beneficial actions. Strengths and opportunities for further development include exploiting non-GABAergic targets, structural analogs, enzymatic production of natural steroids, precursor loading, and novel formulations. The molecular mechanisms of behavioral effects are not fully understood, but study of brain network states involved in emotional processing demonstrate a robust influence on affective states not evident with at least some other GABAergic drugs including benzodiazepines. Ongoing studies with neuroactive steroids will further elucidate the brain and behavioral effects of these compounds as well as likely underpinnings of disease.
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Affiliation(s)
- Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Steven Mennerick
- Department of Psychiatry and Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., St. Louis, MO, 63110, USA.
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4
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Covey DF, Evers AS, Izumi Y, Maguire JL, Mennerick SJ, Zorumski CF. Neurosteroid enantiomers as potentially novel neurotherapeutics. Neurosci Biobehav Rev 2023; 149:105191. [PMID: 37085023 PMCID: PMC10750765 DOI: 10.1016/j.neubiorev.2023.105191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/23/2023]
Abstract
Endogenous neurosteroids and synthetic neuroactive steroids (NAS) are important targets for therapeutic development in neuropsychiatric disorders. These steroids modulate major signaling systems in the brain and intracellular processes including inflammation, cellular stress and autophagy. In this review, we describe studies performed using unnatural enantiomers of key neurosteroids, which are physiochemically identical to their natural counterparts except for rotation of polarized light. These studies led to insights in how NAS interact with receptors, ion channels and intracellular sites of action. Certain effects of NAS show high enantioselectivity, consistent with actions in chiral environments and likely direct interactions with signaling proteins. Other effects show no enantioselectivity and even reverse enantioselectivity. The spectrum of effects of NAS enantiomers raises the possibility that these agents, once considered only as tools for preclinical studies, have therapeutic potential that complements and in some cases may exceed their natural counterparts. Here we review studies of NAS enantiomers from the perspective of their potential development as novel neurotherapeutics.
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Affiliation(s)
- Douglas F Covey
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; Anesthesiology Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Alex S Evers
- Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; Anesthesiology Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Yukitoshi Izumi
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Steven J Mennerick
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles F Zorumski
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
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5
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Izumi Y, Ishikawa M, Nakazawa T, Kunikata H, Sato K, Covey DF, Zorumski CF. Neurosteroids as stress modulators and neurotherapeutics: lessons from the retina. Neural Regen Res 2023; 18:1004-1008. [PMID: 36254981 PMCID: PMC9827771 DOI: 10.4103/1673-5374.355752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Neurosteroids are rapidly emerging as important new therapies in neuropsychiatry, with one such agent, brexanolone, already approved for treatment of postpartum depression, and others on the horizon. These steroids have unique properties, including neuroprotective effects that could benefit a wide range of brain illnesses including depression, anxiety, epilepsy, and neurodegeneration. Over the past 25 years, our group has developed ex vivo rodent models to examine factors contributing to several forms of neurodegeneration in the retina. In the course of this work, we have developed a model of acute closed angle glaucoma that involves incubation of ex vivo retinas under hyperbaric conditions and results in neuronal and axonal changes that mimic glaucoma. We have used this model to determine neuroprotective mechanisms that could have therapeutic implications. In particular, we have focused on the role of both endogenous and exogenous neurosteroids in modulating the effects of acute high pressure. Endogenous allopregnanolone, a major stress-activated neurosteroid in the brain and retina, helps to prevent severe pressure-induced retinal excitotoxicity but is unable to protect against degenerative changes in ganglion cells and their axons under hyperbaric conditions. However, exogenous allopregnanolone, at a pharmacological concentration, completely preserves retinal structure and does so by combined effects on gamma-aminobutyric acid type A receptors and stimulation of the cellular process of macroautophagy. Surprisingly, the enantiomer of allopregnanolone, which is inactive at gamma-aminobutyric acid type A receptors, is equally retinoprotective and acts primarily via autophagy. Both enantiomers are also equally effective in preserving retinal structure and function in an in vivo glaucoma model. These studies in the retina have important implications for the ongoing development of allopregnanolone and other neurosteroids as therapeutics for neuropsychiatric illnesses.
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Affiliation(s)
- Yukitoshi Izumi
- Department of Psychiatry and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Makoto Ishikawa
- Department of Ophthalmic Imaging and Information Analytics; Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Toru Nakazawa
- Department of Ophthalmic Imaging and Information Analytics; Department of Ophthalmology; Department of Retinal Disease Control; Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hiroshi Kunikata
- Department of Ophthalmology; Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kota Sato
- Department of Ophthalmic Imaging and Information Analytics; Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Douglas F Covey
- Department of Psychiatry and Taylor Family Institute for Innovative Psychiatric Research; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles F Zorumski
- Department of Psychiatry and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
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Holubova K, Chvojkova M, Hrcka Krausova B, Vyklicky V, Kudova E, Chodounska H, Vyklicky L, Vales K. Pitfalls of NMDA Receptor Modulation by Neuroactive Steroids. The Effect of Positive and Negative Modulation of NMDA Receptors in an Animal Model of Schizophrenia. Biomolecules 2021; 11:1026. [PMID: 34356650 PMCID: PMC8301783 DOI: 10.3390/biom11071026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 12/26/2022] Open
Abstract
Evidence from clinical and preclinical studies implicates dysfunction of N-methyl-D-aspartate receptors (NMDARs) in schizophrenia progression and symptoms. We investigated the antipsychotic effect of two neuroactive steroids in an animal model of schizophrenia induced by systemic application of MK-801. The neuroactive steroids differ in their mechanism of action at NMDARs. MS-249 is positive, while PA-Glu is a negative allosteric NMDAR modulator. We hypothesized that the positive NMDA receptor modulator would attenuate deficits caused by MK-801 co-application more effectively than PA-Glu. The rats were tested in a battery of tests assessing spontaneous locomotion, anxiety and cognition. Contrary to our expectations, PA-Glu exhibited a superior antipsychotic effect to MS-249. The performance of MS-249-treated rats in cognitive tests differed depending on the level of stress the rats were exposed to during test sessions. In particular, with the increasing severity of stress exposure, the performance of animals worsened. Our results demonstrate that enhancement of NMDAR function may result in unspecific behavioral responses. Positive NMDAR modulation can influence other neurobiological processes besides memory formation, such as anxiety and response to stress.
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Affiliation(s)
- Kristina Holubova
- National Institute of Mental Health, Topolova 748, 25067 Klecany, Czech Republic; (M.C.); (K.V.)
| | - Marketa Chvojkova
- National Institute of Mental Health, Topolova 748, 25067 Klecany, Czech Republic; (M.C.); (K.V.)
| | - Barbora Hrcka Krausova
- Institute of Physiology CAS, Videnska 1083, 14220 Prague, Czech Republic; (B.H.K.); (V.V.); (L.V.)
| | - Vojtech Vyklicky
- Institute of Physiology CAS, Videnska 1083, 14220 Prague, Czech Republic; (B.H.K.); (V.V.); (L.V.)
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry CAS, Flemingovo namesti 542/2, 16000 Prague, Czech Republic; (E.K.); (H.C.)
| | - Hana Chodounska
- Institute of Organic Chemistry and Biochemistry CAS, Flemingovo namesti 542/2, 16000 Prague, Czech Republic; (E.K.); (H.C.)
| | - Ladislav Vyklicky
- Institute of Physiology CAS, Videnska 1083, 14220 Prague, Czech Republic; (B.H.K.); (V.V.); (L.V.)
| | - Karel Vales
- National Institute of Mental Health, Topolova 748, 25067 Klecany, Czech Republic; (M.C.); (K.V.)
- Institute of Physiology CAS, Videnska 1083, 14220 Prague, Czech Republic; (B.H.K.); (V.V.); (L.V.)
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7
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Ziolkowski L, Mordukhovich I, Chen DM, Chisari M, Shu HJ, Lambert PM, Qian M, Zorumski CF, Covey DF, Mennerick S. A neuroactive steroid with a therapeutically interesting constellation of actions at GABA A and NMDA receptors. Neuropharmacology 2021; 183:108358. [PMID: 33115614 PMCID: PMC7736525 DOI: 10.1016/j.neuropharm.2020.108358] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/29/2020] [Accepted: 10/13/2020] [Indexed: 12/30/2022]
Abstract
Neuroactive steroids are an ascendant class of treatment for neuropsychiatric illness. Effects on ligand-gated neurotransmitter receptors appear to be a major mechanism of action. Here we describe a neuroactive steroid with a unique constellation of receptor actions. MQ-221 is a sulfated, 3β-hydroxy neurosteroid analogue that inhibits NMDAR function but also potentiates GABAAR function, thereby exhibiting unusual but potentially clinically desirable effects. Although the compound also exhibited features of other sulfated steroids, namely activation-dependent inhibition of GABAAR function, net potentiation dominated under physiological conditions. Potentiation of GABAAR function was distinct from the mechanism governing potentiation by anesthetic neurosteroids. Inhibition of NMDAR function showed weaker channel activation dependence than pregnanolone sulfate (3α5βPS). MQ-221 was unique among four stereoisomers explored in the pattern of effects at GABAA and NMDARs. Taken together, MQ-221 may represent a new class of compound with unique psychoactive effects and beneficial prospects for treating neuropsychiatric disorders.
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Affiliation(s)
- Luke Ziolkowski
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Isaac Mordukhovich
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Daniel M Chen
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Mariangela Chisari
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Hong-Jin Shu
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Peter M Lambert
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Mingxing Qian
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Charles F Zorumski
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Douglas F Covey
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA; Department of Developmental Biology, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA.
| | - Steven Mennerick
- Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA.
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8
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Chustecka M, Blügental N, Majewski PM, Adamska I. 24 hour patterning in gene expression of pineal neurosteroid biosynthesis in young chickens ( Gallus gallus domesticus L.). Chronobiol Int 2020; 38:46-60. [PMID: 32990093 DOI: 10.1080/07420528.2020.1823404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The pineal gland, one of the three equivalent avian biological clock structures, is also the site of intensive neurosteroid synthesis (7α-hydroxypregnenolone and allopregnanolone). Pineal neurosteroid biosynthesis involves six enzymes: cytochrome P450 side-chain cleavage - Cyp11a1 encoded, cytochrome P4507α - Cyp7b1, 3β-hydroxysteroid dehydrogenase - Hsd3b2, 5α-reductase - Srd5a1, 3α-hydroxysteroid dehydrogenase - Akr1d1, and 5β-reductase - Srd5a3. Regulation of neurosteroid biosynthesis is not fully understood; although it is known that the E4BP4 transcription factor induces activation of biosynthetic cholesterol genes, which are the targets for SREBP (element-binding protein transcription factor). SREBP principal activity in the pineal gland is suppression and inhibition of the Period2 canonical clock gene, suggesting our hypothesis that genes encoding enzymes involved in neurosteroidogenesis are under circadian clock control and are the Clock Control Genes (CCGs). Therefore, through investigation of daily changes in Cyp11a1, Cyp7b1, Hsd3b2, Akr1d1, Srd5a1, and Srd5a3, pineal genes were tested in vivo and in vitro, in cultured pinealocytes. Experiments were carried out on pineal glands taken from 16-day-old chickens in vivo or using in vitro cultures of pinealocytes collected from 16-day-old animals. Both the birds in the in vivo experiments and the pinealocytes were kept under controlled light conditions (LD 12:12) or in constant darkness (DD). Subsequently, materials were prepared for RT-qPCR analysis. Results revealed that three of the six tested genes: Cyp11a1, Cyp7b1, and Srd5a3 demonstrated significant 24-hour variation in in vivo and in vitro. Findings of this study confirm that these genes could be under clock control and satisfy many of the requirements to be identified as CCGs.
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Affiliation(s)
- Magdalena Chustecka
- Department of Animal Physiology, Faculty of Biology, University of Warsaw , Warsaw, Poland
| | - Natalia Blügental
- Department of Animal Physiology, Faculty of Biology, University of Warsaw , Warsaw, Poland
| | - Pawel Marek Majewski
- Department of Animal Physiology, Faculty of Biology, University of Warsaw , Warsaw, Poland
| | - Iwona Adamska
- Department of Animal Physiology, Faculty of Biology, University of Warsaw , Warsaw, Poland
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9
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Tonon MC, Vaudry H, Chuquet J, Guillebaud F, Fan J, Masmoudi-Kouki O, Vaudry D, Lanfray D, Morin F, Prevot V, Papadopoulos V, Troadec JD, Leprince J. Endozepines and their receptors: Structure, functions and pathophysiological significance. Pharmacol Ther 2020; 208:107386. [DOI: 10.1016/j.pharmthera.2019.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/20/2019] [Indexed: 02/06/2023]
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10
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Zorumski CF, Paul SM, Covey DF, Mennerick S. Neurosteroids as novel antidepressants and anxiolytics: GABA-A receptors and beyond. Neurobiol Stress 2019; 11:100196. [PMID: 31649968 PMCID: PMC6804800 DOI: 10.1016/j.ynstr.2019.100196] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 09/24/2019] [Indexed: 01/22/2023] Open
Abstract
The recent FDA approval of the neurosteroid, brexanolone (allopregnanolone), as a treatment for women with postpartum depression, and successful trials of a related neuroactive steroid, SGE-217, for men and women with major depressive disorder offer the hope of a new era in treating mood and anxiety disorders based on the potential of neurosteroids as modulators of brain function. This review considers potential mechanisms contributing to antidepressant and anxiolytic effects of allopregnanolone and other GABAergic neurosteroids focusing on their actions as positive allosteric modulators of GABAA receptors. We also consider their roles as endogenous "stress" modulators and possible additional mechanisms contributing to their therapeutic effects. We argue that further understanding of the molecular, cellular, network and psychiatric effects of neurosteroids offers the hope of further advances in the treatment of mood and anxiety disorders.
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Affiliation(s)
- Charles F. Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Steven M. Paul
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Douglas F. Covey
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Steven Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
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11
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Moffett SX, Klein EA, Brannigan G, Martin JV. L-3,3',5-triiodothyronine and pregnenolone sulfate inhibit Torpedo nicotinic acetylcholine receptors. PLoS One 2019; 14:e0223272. [PMID: 31584962 PMCID: PMC6777777 DOI: 10.1371/journal.pone.0223272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/17/2019] [Indexed: 11/19/2022] Open
Abstract
The nicotinic acetylcholine receptor (nAChR) is an excitatory pentameric ligand-gated ion channel (pLGIC), homologous to the inhibitory γ-aminobutyric acid (GABA) type A receptor targeted by pharmaceuticals and endogenous sedatives. Activation of the GABAA receptor by the neurosteroid allopregnanolone can be inhibited competitively by thyroid hormone (L-3,3’,5-triiodothyronine, or T3), but modulation of nAChR by T3 or neurosteroids has not been investigated. Here we show that allopregnanolone inhibits the nAChR from Torpedo californica at micromolar concentrations, as do T3 and the anionic neurosteroid pregnenolone sulfate (PS). We test for the role of protein and ligand charge in mediated receptor inhibition by varying pH in a narrow range around physiological pH. We find that both T3 and PS become less potent with increasing pH, with remarkably similar trends in IC50 when T3 is neutral at pH < 7.3. After deprotonation of T3 (but no additional deprotonation of PS) at pH 7.3, T3 loses potency more slowly with increasing pH than PS. We interpret this result as indicating the negative charge is not required for inhibition but does increase activity. Finally, we show that both T3 and PS affect nAChR channel desensitization, which may implicate a binding site homologous to one that was recently indicated for accelerated desensitization of the GABAA receptor by PS.
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Affiliation(s)
- Steven X. Moffett
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Eric A. Klein
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Grace Brannigan
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Physics, Rutgers University—Camden, Camden, New Jersey, United States of America
| | - Joseph V. Martin
- Center for Computational and Integrative Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- Department of Biology, Rutgers University—Camden, Camden, New Jersey, United States of America
- * E-mail:
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12
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A neurosteroid analogue with T-type calcium channel blocking properties is an effective hypnotic, but is not harmful to neonatal rat brain. Br J Anaesth 2018; 120:768-778. [PMID: 29576117 DOI: 10.1016/j.bja.2017.12.039] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/22/2017] [Accepted: 01/02/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND More than 4 million children are exposed annually to sedatives and general anaesthetics (GAs) in the USA alone. Recent data suggest that common GAs can be detrimental to brain development causing neurodegeneration and long-term cognitive impairments. Challenged by a recent US Food and Drug Administration (FDA) warning about potentially neurotoxic effects of GAs in children, there is an urgent need to develop safer GAs. METHODS Postnatal Day 7 (P7) rat pups of both sexes were exposed to six (repeated every 2 h) injections of equipotent hypnotic doses of ketamine or the neuroactive steroid (3β,5β,17β)-3-hydroxyandrostane-17-carbonitrile (3β-OH) for 12 h. Loss of righting reflex was used to assess hypnotic properties and therapeutic index; quantitative caspase-3 immunohistochemistry was used to assess developmental neuroapoptosis; patch-clamp recordings in acute brain slices were used to assess the effects of 3β-OH on neuronal excitability and synaptic transmission. Cognitive abilities of rats exposed to ketamine, 3β-OH, or vehicle at P7 were assessed in young adulthood using the radial arm maze. RESULTS The neuroactive steroid 3β-OH has a therapeutic index similar to ketamine, a commonly used clinical GA. We report that 3β-OH is safe and, unlike ketamine, does not cause neuroapoptosis or impair cognitive development when administered to P7 rat pups. Interestingly, 3β-OH blocks T-type calcium channels and presynaptically dampens synaptic transmission at hypnotically-relevant brain concentrations, but it lacks a direct effect on γ-aminobutyric acid A or glutamate-gated ion channels. CONCLUSIONS The neurosteroid 3β-OH is a relatively safe hypnotic that warrants further consideration for paediatric anaesthesia.
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13
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Vallée M. Neurosteroids and potential therapeutics: Focus on pregnenolone. J Steroid Biochem Mol Biol 2016; 160:78-87. [PMID: 26433186 DOI: 10.1016/j.jsbmb.2015.09.030] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/18/2015] [Accepted: 09/21/2015] [Indexed: 12/26/2022]
Abstract
Considerable evidence from preclinical and clinical studies shows that steroids and in particular neurosteroids are important endogenous modulators of several brain-related functions. In this context, it remains to be elucidated whether neurosteroids may serve as biomarkers in the diagnosis of disorders and might have therapeutic potential for the treatment of these disorders. Pregnenolone (PREG) is the main steroid synthesized from cholesterol in mammals and invertebrates. PREG has three main sources of synthesis, the gonads, adrenal glands and brain and is submitted to various metabolizing pathways which are modulated depending on various factors including species, steroidogenic tissues and steroidogenic enzymes. Looking at the whole picture of steroids, PREG is often known as the precursor to other steroids and not as an active steroid per se. Actually, physiological and brain functions have been studied mainly for steroids that are very active either binding to specific intracellular receptors, or modulating with high affinity the abundant membrane receptors, GABAA or NMDA receptors. However, when high sensitive and specific methodological approaches were available to analyze low concentrations of steroids and then match endogenous levels of different steroid metabolomes, several studies have reported more significant alterations in PREG than in other steroids in extraphysiological or pathological conditions, suggesting that PREG could play a functional role as well. Additionally, several molecular targets of PREG were revealed in the mammalian brain and beneficial effects of PREG have been demonstrated in preclinical and clinical studies. On this basis, this review will be divided into three parts. The first provides a brief overview of the molecular targets of PREG and the pharmacological effects observed in animal and human studies. The second will focus on the possible functional role of PREG with an outline of the modulation of PREG levels in animal and in human research. Finally, the review will highlight the possible therapeutic uses of PREG that point towards the development of pregnenolone-like molecules.
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Affiliation(s)
- Monique Vallée
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction, Bordeaux F33077, France; Université de Bordeaux, Bordeaux F33077, France.
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14
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El-Desoky ESI, Reyad M, Afsah EM, Dawidar AAM. Synthesis and chemical reactions of the steroidal hormone 17α-methyltestosterone. Steroids 2016; 105:68-95. [PMID: 26639430 DOI: 10.1016/j.steroids.2015.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 11/11/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022]
Abstract
Structural modifications of natural products with complex structures like steroids require great synthetic effort. A review of literature is presented on the chemistry of the steroidal hormone 17α-methyltestosterone that is approved by Food and Drug Administration (FDA) in the United States as an androgen for estrogen-androgen hormone replacement therapy treatment. The analog also offers special possibilities for the prevention/treatment of hormone-sensitive cancers. The testosterone skeleton has important functionalities in the molecule that can act as a carbonyl component, an active methylene compound, α,β-unsaturated enone and tertiary hydroxyl group in various chemical reactions to access stereoisomeric steroidal compounds with potent activity. In addition, microbiological methods of synthesis and transformation of this hormone are presented.
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Affiliation(s)
- El-Sayed Ibrahim El-Desoky
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
| | - Mahmoud Reyad
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt.
| | - Elsayed Mohammed Afsah
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
| | - Abdel-Aziz Mahmoud Dawidar
- Chemistry Department, Faculty of Science, Mansoura University, 60, El Gomhoria Street, Mansoura Dakahlia 35516, Egypt
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15
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Interactions of L-3,5,3'-Triiodothyronine [corrected], Allopregnanolone, and Ivermectin with the GABAA Receptor: Evidence for Overlapping Intersubunit Binding Modes. PLoS One 2015; 10:e0139072. [PMID: 26421724 PMCID: PMC4589331 DOI: 10.1371/journal.pone.0139072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/09/2015] [Indexed: 11/28/2022] Open
Abstract
Structural mechanisms of modulation of γ-aminobutyric acid (GABA) type A receptors by neurosteroids and hormones remain unclear. The thyroid hormone L-3,5,3’-triiodothyronine (T3) inhibits GABAA receptors at micromolar concentrations and has common features with neurosteroids such as allopregnanolone (ALLOP). Here we use functional experiments on α2β1γ2 GABAA receptors expressed in Xenopus oocytes to detect competitive interactions between T3 and an agonist (ivermectin, IVM) with a crystallographically determined binding site at subunit interfaces in the transmembrane domain of a homologous receptor (glutamate-gated chloride channel, GluCl). T3 and ALLOP also show competitive effects, supporting the presence of both a T3 and ALLOP binding site at one or more subunit interfaces. Molecular dynamics (MD) simulations over 200 ns are used to investigate the dynamics and energetics of T3 in the identified intersubunit sites. In these simulations, T3 molecules occupying all intersubunit sites (with the exception of the α-β interface) display numerous energetically favorable conformations with multiple hydrogen bonding partners, including previously implicated polar/acidic sidechains and a structurally conserved deformation in the M1 backbone.
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16
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Seljeset S, Laverty D, Smart TG. Inhibitory Neurosteroids and the GABAA Receptor. DIVERSITY AND FUNCTIONS OF GABA RECEPTORS: A TRIBUTE TO HANNS MÖHLER, PART A 2015; 72:165-87. [DOI: 10.1016/bs.apha.2014.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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17
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Hénin J, Salari R, Murlidaran S, Brannigan G. A predicted binding site for cholesterol on the GABAA receptor. Biophys J 2014; 106:1938-49. [PMID: 24806926 DOI: 10.1016/j.bpj.2014.03.024] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/03/2014] [Accepted: 03/14/2014] [Indexed: 12/29/2022] Open
Abstract
Modulation of the GABA type A receptor (GABAAR) function by cholesterol and other steroids is documented at the functional level, yet its structural basis is largely unknown. Current data on structurally related modulators suggest that cholesterol binds to subunit interfaces between transmembrane domains of the GABAAR. We construct homology models of a human GABAAR based on the structure of the glutamate-gated chloride channel GluCl of Caenorhabditis elegans. The models show the possibility of previously unreported disulfide bridges linking the M1 and M3 transmembrane helices in the α and γ subunits. We discuss the biological relevance of such disulfide bridges. Using our models, we investigate cholesterol binding to intersubunit cavities of the GABAAR transmembrane domain. We find that very similar binding modes are predicted independently by three approaches: analogy with ivermectin in the GluCl crystal structure, automated docking by AutoDock, and spontaneous rebinding events in unbiased molecular dynamics simulations. Taken together, the models and atomistic simulations suggest a somewhat flexible binding mode, with several possible orientations. Finally, we explore the possibility that cholesterol promotes pore opening through a wedge mechanism.
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Affiliation(s)
- Jérôme Hénin
- Laboratoire de Biochimie Théorique, CNRS, IBPC, and Université Paris Diderot, Paris, France
| | - Reza Salari
- Department of Physics, Rutgers University-Camden, Camden, New Jersey; Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, New Jersey
| | - Sruthi Murlidaran
- Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, New Jersey
| | - Grace Brannigan
- Department of Physics, Rutgers University-Camden, Camden, New Jersey; Center for Computational and Integrative Biology, Rutgers University-Camden, Camden, New Jersey.
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18
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Challal S, Buenafe OEM, Queiroz EF, Maljevic S, Marcourt L, Bock M, Kloeti W, Dayrit FM, Harvey AL, Lerche H, Esguerra CV, de Witte PAM, Wolfender JL, Crawford AD. Zebrafish bioassay-guided microfractionation identifies anticonvulsant steroid glycosides from the Philippine medicinal plant Solanum torvum. ACS Chem Neurosci 2014; 5:993-1004. [PMID: 25127088 DOI: 10.1021/cn5001342] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Medicinal plants used for the treatment of epilepsy are potentially a valuable source of novel antiepileptic small molecules. To identify anticonvulsant secondary metabolites, we performed an in vivo, zebrafish-based screen of medicinal plants used in Southeast Asia for the treatment of seizures. Solanum torvum Sw. (Solanaceae) was identified as having significant anticonvulsant activity in zebrafish larvae with seizures induced by the GABAA antagonist pentylenetetrazol (PTZ). This finding correlates well with the ethnomedical use of this plant in the Philippines, where a water decoction of S. torvum leaves is used to treat epileptic seizures. HPLC microfractionation of the bioactive crude extract, in combination with the in vivo zebrafish seizure assay, enabled the rapid localization of several bioactive compounds that were partially identified online by UHPLC-TOF-MS as steroid glycosides. Targeted isolation of the active constituents from the methanolic extract enabled the complete de novo structure identification of the six main bioactive compounds that were also present in the traditional preparation. To partially mimic the in vivo metabolism of these triterpene glycosides, their common aglycone was generated by acid hydrolysis. The isolated molecules exhibited significant anticonvulsant activity in zebrafish seizure assays. These results underscore the potential of zebrafish bioassay-guided microfractionation to rapidly identify novel bioactive small molecules of natural origin.
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Affiliation(s)
- Soura Challal
- School
of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Olivia E. M. Buenafe
- Laboratory
for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological
Sciences, KU Leuven - University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Emerson F. Queiroz
- School
of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Snezana Maljevic
- Department
of Neurology and Epileptology, Hertie Institute for Clinical Brain
Research, University of Tübingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany
| | - Laurence Marcourt
- School
of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Merle Bock
- Department
of Neurology and Epileptology, Hertie Institute for Clinical Brain
Research, University of Tübingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany
| | - Werner Kloeti
- School
of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Fabian M. Dayrit
- Department
of Chemistry, Ateneo de Manila University, Loyola Heights, 1108 Quezon City, Philippines
| | - Alan L. Harvey
- Strathclyde
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, Scotland, United Kingdom
| | - Holger Lerche
- Department
of Neurology and Epileptology, Hertie Institute for Clinical Brain
Research, University of Tübingen, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany
| | - Camila V. Esguerra
- Laboratory
for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological
Sciences, KU Leuven - University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Peter A. M. de Witte
- Laboratory
for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological
Sciences, KU Leuven - University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Jean-Luc Wolfender
- School
of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Alexander D. Crawford
- Laboratory
for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological
Sciences, KU Leuven - University of Leuven, Herestraat 49, 3000 Leuven, Belgium
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Neuroprotection by the synthetic neurosteroid enantiomers ent-PREGS and ent-DHEAS against Aβ₂₅₋₃₅ peptide-induced toxicity in vitro and in vivo in mice. Psychopharmacology (Berl) 2014; 231:3293-3312. [PMID: 24481566 PMCID: PMC4188413 DOI: 10.1007/s00213-014-3435-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
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.
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20
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Vallée M. Structure-activity relationship studies on neuroactive steroids in memory, alcohol and stress-related functions: a crucial benefit from endogenous level analysis. Psychopharmacology (Berl) 2014; 231:3243-55. [PMID: 24781520 DOI: 10.1007/s00213-014-3593-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/11/2014] [Indexed: 02/07/2023]
Abstract
RATIONALE New research findings in the field of neuroactive steroids strongly suggest that to understand their role in physiopathology, it is essential to accurately measure their tissue levels. Through his broad chemical expertise and extensive knowledge of steroids, Dr. Robert H. Purdy pioneered structure-activity relationship studies on these compounds and developed innovative detection assays that are essential to assess their function in biological tissues. OBJECTIVE The goal of the present paper is to point out the specific contributions of Dr. Purdy and his collaborators to the current knowledge on the role of neuroactive steroids in the modulation of memory and alcohol- and stress-related effects with particular emphasis on the detection assays he developed to assess their endogenous levels. Reviewed here are the major results as well as the original and valuable methodological strategies issued by the long-term collaboration between Dr Purdy and many scientists worldwide on the investigation of the structure-activity relationship of neuroactive steroids. RESULTS Altogether, the data presented herein put forward the original notion that knowledge of the chemical structure of steroids is essential for their detection and the understanding of their role in physiological and pathological conditions, including the stress response. CONCLUSIONS The current challenge is to identify and quantify using appropriate methods neuroactive steroids in the context of both animal and clinical studies in order to reveal how their levels change under physiological and disease states. Dr. Purdy passed away in September 2012, but scientists all over the world will always be grateful for his pioneering work on steroid chemistry and for his great enthusiasm in research.
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Affiliation(s)
- Monique Vallée
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction, Bordeaux, 33077, France,
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Szánti-Pintér E, Csók Z, Berente Z, Kollár L, Skoda-Földes R. Synthesis of novel 13α-18-nor-16-carboxamido steroids via a palladium-catalyzed aminocarbonylation reaction. Steroids 2013; 78:1177-82. [PMID: 24012726 DOI: 10.1016/j.steroids.2013.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 08/07/2013] [Accepted: 08/20/2013] [Indexed: 10/26/2022]
Abstract
13α-18-nor-16-Carboxamido steroids were synthesized via a palladium-catalyzed aminocarbonylation reaction of the corresponding iodoalkenes. The starting material was an unnatural 13α-16-keto steroid, obtained by a Wagner-Meerwein rearrangement of a 16α,17α-epoxide in the presence of [BMIM][BF4]. The 13α-16-keto steroid was converted to a mixture of 16-iodo-16-ene and 16-iodo-15-ene derivatives in two steps by Barton's methodology. Aminocarbonylation of the steroidal alkenyl iodides was carried out using different primary and secondary amines as nucleophiles. The products, 16-carboxamido-16-ene and 16-carboxamido-15-ene derivatives, were obtained in good yields and were characterized by (1)H and (13)C NMR, IR and MS. The reduction of the above two unsaturated carboxamides resulted in the same product, 17α-methyl-16α-carboxamido-androstane.
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Affiliation(s)
- Eszter Szánti-Pintér
- University of Pannonia, Institute of Chemistry, Department of Organic Chemistry, Egyetem u. 10, P.O. Box 158, H-8200 Veszprém, Hungary
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di Michele F, Luchetti S, Bernardi G, Romeo E, Longone P. Neurosteroid and neurotransmitter alterations in Parkinson's disease. Front Neuroendocrinol 2013; 34:132-42. [PMID: 23563222 DOI: 10.1016/j.yfrne.2013.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/17/2013] [Accepted: 03/25/2013] [Indexed: 01/13/2023]
Abstract
Parkinson's disease (PD) is associated with a massive loss of dopaminergic cells in the substantia nigra leading to dopamine hypofunction and alteration of the basal ganglia circuitry. These neurons, are under the control, among others, of the excitatory glutamatergic and inhibitory γ-aminobutyric acid (GABA) systems. An imbalance between these systems may contribute to excitotoxicity and dopaminergic cell death. Neurosteroids, a group of steroid hormones synthesized in the brain, modulate the function of several neurotransmitter systems. The substantia nigra of the human brain expresses high concentrations of allopregnanolone (3α, 5αtetrahydroprogesterone), a neurosteroid that positively modulates the action of GABA at GABAA receptors and of 5α-dihydroprogesterone, a neurosteroid acting at the genomic level. This article reviews the roles of NS acting as neuroprotectants and as GABAA receptor agonists in the physiology and pathophysiology of the basal ganglia, their impact on dopaminergic cell activity and survival, and potential therapeutic application in PD.
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Neurosteroids, stress and depression: potential therapeutic opportunities. Neurosci Biobehav Rev 2012; 37:109-22. [PMID: 23085210 DOI: 10.1016/j.neubiorev.2012.10.005] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/28/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022]
Abstract
Neurosteroids are potent and effective neuromodulators that are synthesized from cholesterol in the brain. These agents and their synthetic derivatives influence the function of multiple signaling pathways including receptors for γ-aminobutyric acid (GABA) and glutamate, the major inhibitory and excitatory neurotransmitters in the central nervous system (CNS). Increasing evidence indicates that dysregulation of neurosteroid production plays a role in the pathophysiology of stress and stress-related psychiatric disorders, including mood and anxiety disorders. In this paper, we review the mechanisms of neurosteroid action in brain with an emphasis on those neurosteroids that potently modulate the function of GABA(A) receptors. We then discuss evidence indicating a role for GABA and neurosteroids in stress and depression, and focus on potential strategies that can be used to manipulate CNS neurosteroid synthesis and function for therapeutic purposes.
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Zorumski CF, Izumi Y. NMDA receptors and metaplasticity: mechanisms and possible roles in neuropsychiatric disorders. Neurosci Biobehav Rev 2012; 36:989-1000. [PMID: 22230702 DOI: 10.1016/j.neubiorev.2011.12.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 11/14/2011] [Accepted: 12/22/2011] [Indexed: 02/08/2023]
Abstract
N-methyl-D-aspartate receptors (NMDARs) are key components of neural signaling, playing roles in synaptic transmission and in the synaptic plasticity thought to underlie learning and memory. NMDAR activation can also have neurotoxic consequences contributing to several forms of neurodegeneration. Additionally, NMDARs can modulate neuronal function and regulate the ability of synapses to undergo synaptic plasticity. Evidence gathered over the past 20 years strongly supports the idea that untimely activation of NMDARs impairs the induction of long-term potentiation (LTP) by a form of metaplasticity. This metaplasticity can be triggered by multiple stimuli including physiological receptor activation, and metabolic and behavioral stressors. These latter findings raise the possibility that NMDARs contribute to cognitive dysfunction associated with neuropsychiatric disorders. This paper examines NMDAR metaplasticity and its potential role in cognition. Recent studies using NMDAR antagonists for therapeutic purposes also raise the possibility that metaplasticity may contribute to clinical effects of certain drugs.
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Affiliation(s)
- Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Panzica GC, Balthazart J, Frye CA, Garcia-Segura LM, Herbison AE, Mensah-Nyagan AG, McCarthy MM, Melcangi RC. Milestones on Steroids and the Nervous System: 10 years of basic and translational research. J Neuroendocrinol 2012; 24:1-15. [PMID: 22188420 DOI: 10.1111/j.1365-2826.2011.02265.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
During the last 10 years, the conference on 'Steroids and Nervous System' held in Torino (Italy) has been an important international point of discussion for scientists involved in this exciting and expanding research field. The present review aims to recapitulate the main topics that have been presented through the various meetings. Two broad areas have been explored: the impact of gonadal hormones on brain circuits and behaviour, as well as the mechanism of action of neuroactive steroids. Relationships among steroids, brain and behaviour, the sexual differentiation of the brain and the impact of gonadal hormones, the interactions of exogenous steroidal molecules (endocrine disrupters) with neural circuits and behaviour, and how gonadal steroids modulate the behaviour of gonadotrophin-releasing hormone neurones, have been the topics of several lectures and symposia during this series of meetings. At the same time, many contributions have been dedicated to the biosynthetic pathways, the physiopathological relevance of neurosteroids, the demonstration of the cellular localisation of different enzymes involved in neurosteroidogenesis, the mechanisms by which steroids may exert some of their effects, both the classical and nonclassical actions of different steroids, the role of neuroactive steroids on neurodegeneration, neuroprotection, and the response of the neural tissue to injury. In these 10 years, this field has significantly advanced and neuroactive steroids have emerged as new potential therapeutic tools to counteract neurodegenerative events.
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Affiliation(s)
- G C Panzica
- Laboratory of Neuroendocrinology, Department of Anatomy, Pharmacology and Forensic Medicine, Neuroscience Institute of Turin (NIT), University of Torino, Torino, Italy.
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Krasowski MD, Hopfinger AJ. The discovery of new anesthetics by targeting GABAAreceptors. Expert Opin Drug Discov 2011; 6:1187-201. [DOI: 10.1517/17460441.2011.627324] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Rammouz G, Lecanu L, Papadopoulos V. Oxidative Stress-Mediated Brain Dehydroepiandrosterone (DHEA) Formation in Alzheimer's Disease Diagnosis. Front Endocrinol (Lausanne) 2011; 2:69. [PMID: 22654823 PMCID: PMC3356139 DOI: 10.3389/fendo.2011.00069] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/19/2011] [Indexed: 02/06/2023] Open
Abstract
Neurosteroids are steroids made by brain cells independently of peripheral steroidogenic sources. The biosynthesis of most neurosteroids is mediated by proteins and enzymes similar to those identified in the steroidogenic pathway of adrenal and gonadal cells. Dehydroepiandrosterone (DHEA) is a major neurosteroid identified in the brain. Over the years we have reported that, unlike other neurosteroids, DHEA biosynthesis in rat, bovine, and human brain is mediated by an oxidative stress-mediated mechanism, independent of the cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17A1) enzyme activity found in the periphery. This alternative pathway is induced by pro-oxidant agents, such as Fe(2+) and β-amyloid peptide. Neurosteroids are involved in many aspects of brain function, and as such, are involved in various neuropathologies, including Alzheimer's disease (AD). AD is a progressive, yet irreversible neurodegenerative disease for which there are limited means for ante-mortem diagnosis. Using brain tissue specimens from control and AD patients, we provided evidence that DHEA is formed in the AD brain by the oxidative stress-mediated metabolism of an unidentified precursor, thus depleting levels of the precursor in the blood stream. We tested for the presence of this DHEA precursor in human serum using a Fe(2+)-based reaction and determined the amounts of DHEA formed. Fe(2+) treatment of the serum resulted in a dramatic increase in DHEA levels in control patients, whereas only a moderate or no increase was observed in AD patients. The DHEA variation after oxidation correlated with the patients' cognitive and mental status. In this review, we present the cumulative evidence for oxidative stress as a natural regulator of DHEA formation and the use of this concept to develop a blood-based diagnostic tool for neurodegenerative diseases linked to oxidative stress, such as AD.
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Affiliation(s)
- Georges Rammouz
- Department of Medicine, The Research Institute of the McGill University Health Centre, McGill UniversityMontreal, QC, Canada
| | - Laurent Lecanu
- Department of Medicine, The Research Institute of the McGill University Health Centre, McGill UniversityMontreal, QC, Canada
| | - Vassilios Papadopoulos
- Department of Medicine, The Research Institute of the McGill University Health Centre, McGill UniversityMontreal, QC, Canada
- Department of Biochemistry, McGill UniversityMontreal, QC, Canada
- Department of Pharmacology and Therapeutics, McGill UniversityMontreal, QC, Canada
- *Correspondence: Vassilios Papadopoulos, The Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, C10-148, Montreal, QC, Canada H3G 1A4. e-mail:
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Do Rego JL, Seong JY, Burel D, Leprince J, Luu-The V, Tsutsui K, Tonon MC, Pelletier G, Vaudry H. Neurosteroid biosynthesis: enzymatic pathways and neuroendocrine regulation by neurotransmitters and neuropeptides. Front Neuroendocrinol 2009; 30:259-301. [PMID: 19505496 DOI: 10.1016/j.yfrne.2009.05.006] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 05/12/2009] [Accepted: 05/21/2009] [Indexed: 01/09/2023]
Abstract
Neuroactive steroids synthesized in neuronal tissue, referred to as neurosteroids, are implicated in proliferation, differentiation, activity and survival of nerve cells. Neurosteroids are also involved in the control of a number of behavioral, neuroendocrine and metabolic processes such as regulation of food intake, locomotor activity, sexual activity, aggressiveness, anxiety, depression, body temperature and blood pressure. In this article, we summarize the current knowledge regarding the existence, neuroanatomical distribution and biological activity of the enzymes responsible for the biosynthesis of neurosteroids in the brain of vertebrates, and we review the neuronal mechanisms that control the activity of these enzymes. The observation that the activity of key steroidogenic enzymes is finely tuned by various neurotransmitters and neuropeptides strongly suggests that some of the central effects of these neuromodulators may be mediated via the regulation of neurosteroid production.
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Affiliation(s)
- Jean Luc Do Rego
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 413, 76821 Mont-Saint-Aignan, France
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Shu HJ, Eisenman LN, Wang C, Bandyopadhyaya AK, Krishnan K, Taylor A, Benz AM, Manion B, Evers AS, Covey DF, Zorumski CF, Mennerick S. Photodynamic effects of steroid-conjugated fluorophores on GABAA receptors. Mol Pharmacol 2009; 76:754-65. [PMID: 19596835 DOI: 10.1124/mol.109.057687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have shown that fluorescent, 7-nitro-2,1,3-benzoxadiazol-4-yl amino (NBD)-conjugated neurosteroid analogs photopotentiate GABA(A) receptor function. These compounds seem to photosensitize a modification of receptor function, resulting in long-lived increases in responses to exogenous or synaptic GABA. Here we extend this work to examine the effectiveness of different fluorophore positions, conjugations, steroid structures, and fluorophores. Our results are generally in agreement with the idea that steroids with activity at GABA(A) receptors are the most potent photopotentiators. In particular, we find that an unnatural enantiomer of an effective photopotentiating steroid is relatively weak, excluding the idea that membrane solubility alone, which is identical for enantiomer pairs, is solely responsible for potent photopotentiation. Furthermore, there is a significant correlation between baseline GABA(A) receptor activity and photopotentiation. Curiously, both sulfated steroids, which bind a presumed external neurosteroid antagonist site, and hydroxysteroids, which bind an independent site, are effective. We also find that a rhodamine dye conjugated to a 5beta-reduced 3alpha-hydroxy steroid is a particularly potent and effective photopotentiator, with minimal baseline receptor activity up to 10 muM. Steroid conjugated fluorescein and Alexa Fluor 546 also supported photopotentiation, although the Alexa Fluor conjugate was weaker and required 10-fold higher concentration to achieve similar potentiation to the best NBD and rhodamine conjugates. Filling cells with steroid-conjugated or free fluorophores via whole-cell patch pipette did not support photopotentiation. FM1-43, another membrane-targeted, structurally unrelated fluorophore, also produced photopotentiation at micromolar concentrations. We conclude that further optimization of fluorophore and carrier could produce an effective, selective, light-sensitive GABA(A) receptor modulator.
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Affiliation(s)
- Hong-Jin Shu
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
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Rego JLD, Seong JY, Burel D, Luu-The V, Larhammar D, Tsutsui K, Pelletier G, Tonon MC, Vaudry H. Steroid Biosynthesis within the Frog Brain. Ann N Y Acad Sci 2009; 1163:83-92. [DOI: 10.1111/j.1749-6632.2008.03664.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Involvement of GABAA receptor in Bufo arenarum oocyte maturation. ZYGOTE 2008; 16:135-44. [PMID: 18405434 DOI: 10.1017/s0967199408004656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Amphibian oocytes meiotic arrest is released under the stimulus of progesterone; this hormone interacts with the oocyte surface and starts a cascade of events leading to the activation of a cytoplasmic maturation promoting factor (MPF) that induces germinal vesicle breakdown (GVBD), chromosome condensation and extrusion of the first polar body. The aim of this work was to determine whether the activation of a GABAA receptor is able to induce GVBD in fully grown denuded oocytes of Bufo arenarum and to analyse its possible participation in progesterone-induced maturation. We also evaluated the role of purines and phospholipids in the maturation process induced by a GABAA receptor agonist such as muscimol. Our results indicated that the activation of the GABAA receptor by muscimol induces maturation in a dose- and time-dependent manner and that this activation is a genuine maturation that enables oocytes to form pronuclei. Assays with a receptor antagonist, picrotoxine, showed that the maturation induced by muscimol was inhibited. Treatment with picrotoxine, however, shows that the participation of GABAA receptor in progesterone-induced maturation is not significant. In addition, our results indicate that high intracellular levels of purines obtained by the use of db-AMPc and theophylline or the inhibition of the phosphatidylinositol 4,5-bisphosphate (PIP2 hydrolysis by neomycin and PIP2 turn over by LiCl, respectively, inhibited the maturation induced by muscimol. Treatment with H-7 indicated, however, that PKC activation is not necessary for GVBD induced by the GABAA receptor agonist. Results suggest that the transduction pathway used by the GABAA receptor to induce maturation is different from those used by progesterone.
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Wang MD, Borra VB, Strömberg J, Lundgren P, Haage D, Bäckström T. Neurosteroids 3beta, 20 (R/S)-pregnandiols decrease offset rate of the GABA-site activation at the recombinant GABA A receptor. Eur J Pharmacol 2008; 586:67-73. [PMID: 18374329 DOI: 10.1016/j.ejphar.2008.02.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2007] [Revised: 02/07/2008] [Accepted: 02/20/2008] [Indexed: 10/22/2022]
Abstract
Neurosteroids directly modulate ligand gated ion channels such as GABA A receptors. Two such molecules, 3beta-OH A-ring reduced pregnane steroids and pregnenolone sulfate (PS), inhibit recombinant GABA A receptor. Using a two-electrode voltage-clamp technique, we compared the effect of 5alpha-pregnan-3beta,20(S)-diol (UC1019), 5beta-pregnan-3beta, 20(R)-diol (UC1020) and PS on the activation onset and offset times of the recombinant GABA A receptor (rat alpha1beta2gamma2L) in Xenopus oocytes. Rapid solution changes allowed the kinetic analysis of GABA-evoked currents. Steroids were co-applied with 30 microM GABA for 10 s, followed by a 80 s washout period. PS (> ir =0.3 microM) moderately increased the slow onset rate (k(on-S)) of GABA-response. PS had no significant effects on the fast onset rate (k(on-F)). UC1019 and UC1020 decreased the k(on-S) of the GABA-response in a concentration-dependent manner with no significant effects on the k(on-F). Like PS, UC1019 and UC1020 decreased the slow offset rates (k(off-S)). In addition, PS increased the fast offset rate (k(off-F)) in a concentration-dependent manner, while UC1019 and UC1020 decreased k(off-F). The EC50 of PS to increase k(off-F) was calculated as 0.47+/-0.1 microM. The corresponding IC50 values of UC1019 and UC1020 to decrease k(off-F) were 5.0+/-0.5 microM and 8.4+/-0.9 microM, respectively. These results suggest differential actions of PS and 3beta, 20(R/S)-pregnandiols on the offset time course of GABA-site activation.
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Affiliation(s)
- Ming-De Wang
- Umeå Neurosteroid Research Center, Department of Clinical Science, Obstetrics and Gynecology, Sweden.
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Scaglione JB, Jastrzebska I, Krishnan K, Li P, Akk G, Manion BD, Benz A, Taylor A, Rath NP, Evers AS, Zorumski CF, Mennerick S, Covey DF. Neurosteroid analogues. 14. Alternative ring system scaffolds: GABA modulatory and anesthetic actions of cyclopenta[b]phenanthrenes and cyclopenta[b]anthracenes. J Med Chem 2008; 51:1309-18. [PMID: 18275132 DOI: 10.1021/jm701128r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although the structural features of binding sites for neuroactive steroids on gamma-aminobutryic acid type A (GABA A) receptors are still largely unknown, structure-activity studies have established a pharmacophore for potent enhancement of GABA A receptor function by neuroactive steroids. This pharmacophore emphasizes the importance of the position and stereochemistry of hydrogen-bonding groups on the steroid. However, the importance of the steroid ring system in mediating hydrophobic interactions with the GABA A receptor is unclear. We have taken the cyclopenta[ b]phenanthrene (tetracyclic compounds with a nonlinear ring system different from that of steroids) and cyclopenta[ b]anthracene (tetracyclic molecules with a linear 6-6-6-5 carbocyclic ring system) ring systems and properly substituted them to satisfy the pharmacophore requirements of the critical hydrogen-bond donor and acceptor groups found in neuroactive steroids. We have found these cyclopenta[ b]phenanthrene and cyclopenta[ b]anthracene analogues to have potent activity at the GABA A receptor, rivaling that of the most potent steroid modulators. Single-channel analysis of electrophysiological data indicates that similarly substituted analogues in the different ring systems affect the kinetic components of macroscopic currents in different ways. Mutations to the hydrogen bonding amino acids at the putative steroid binding site (alpha1Q241L mutation and alpha1N407A/Y410F double mutation) produce similar effects on macroscopic current amplitude by the different ring system analogues suggesting that the different kinetic effects are explained by the precise interactions of each analogue with the same binding site(s).
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Affiliation(s)
- Jamie B Scaglione
- Department of Molecular Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Schumacher M, Liere P, Akwa Y, Rajkowski K, Griffiths W, Bodin K, Sjövall J, Baulieu EE. Pregnenolone sulfate in the brain: a controversial neurosteroid. Neurochem Int 2007; 52:522-40. [PMID: 18068870 DOI: 10.1016/j.neuint.2007.08.022] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 07/25/2007] [Accepted: 08/31/2007] [Indexed: 12/30/2022]
Abstract
Pregnenolone sulfate (PREGS) has been shown, either at high nanomolar or at micromolar concentrations, to increase neuronal activity by inhibiting GABAergic and by stimulating glutamatergic neurotransmission. PREGS is also a potent modulator of sigma type 1 (sigma1) receptors. It has been proposed that these actions of PREGS underlie its neuropharmacological effects, and in particular its influence on memory processes. On the other hand, the PREGS-mediated increase in neuronal excitability may become dangerous under particular conditions, for example in the case of excitotoxic stress or convulsions. However, the physiopathological significance of these observations has recently been put into question by the failure to detect significant levels of PREGS within the brain and plasma of rats and mice, either by direct analytical methods based on liquid chromatography/mass spectrometry (LC/MS) or enzyme linked immunosorbent assay (ELISA) with specific antibodies against PREGS, or by indirect gas chromatography/mass spectrometry (GC/MS) analysis with improved sample workup. These recent results have not come to the attention of a large number of neurobiologists interested in steroid sulfates. However, although available direct analytical methods have failed to detect levels of PREGS above 0.1-0.3 ng/g in brain tissue, it may be premature to completely exclude the local formation of biologically active PREGS within specific and limited compartments of the nervous system. In contrast to the situation in rodents, significant levels of sulfated 3beta-hydroxysteroids have been measured in human plasma and brain. Previous indirect measures of steroid sulfates by radioimmunoassays (RIA) or GC/MS had detected elevated levels of PREGS in rodent brain. The discrepancies between the results of different assay procedures have revealed the danger of indirect analysis of steroid sulfates. Indeed, PREGS must be solvolyzed/hydrolyzed prior to RIA or GC/MS analysis, and it is the released, unconjugated PREG which is then quantified. Extreme caution needs to be exercised during the preparation of samples for RIA or GC/MS analysis, because the fraction presumed to contain only steroid sulfates can be contaminated by nonpolar components from which PREG is generated by the solvolysis/hydrolysis/derivatization reactions.
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Affiliation(s)
- Michael Schumacher
- UMR 788 Inserm, University Paris-Sud 11, 80 rue du Général Leclerc, 94276 Kremlin-Bicêtre, France.
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Schumacher M, Guennoun R, Stein DG, De Nicola AF. Progesterone: Therapeutic opportunities for neuroprotection and myelin repair. Pharmacol Ther 2007; 116:77-106. [PMID: 17659348 DOI: 10.1016/j.pharmthera.2007.06.001] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 06/01/2007] [Indexed: 11/24/2022]
Abstract
Progesterone and its metabolites promote the viability of neurons in the brain and spinal cord. Their neuroprotective effects have been documented in different lesion models, including traumatic brain injury (TBI), experimentally induced ischemia, spinal cord lesions and a genetic model of motoneuron disease. Progesterone plays an important role in developmental myelination and in myelin repair, and the aging nervous system appears to remain sensitive to some of progesterone's beneficial effects. Thus, the hormone may promote neuroregeneration by several different actions by reducing inflammation, swelling and apoptosis, thereby increasing the survival of neurons, and by promoting the formation of new myelin sheaths. Recognition of the important pleiotropic effects of progesterone opens novel perspectives for the treatment of brain lesions and diseases of the nervous system. Over the last decade, there have been a growing number of studies showing that exogenous administration of progesterone or some of its metabolites can be successfully used to treat traumatic brain and spinal cord injury, as well as ischemic stroke. Progesterone can also be synthesized by neurons and by glial cells within the nervous system. This finding opens the way for a promising therapeutic strategy, the use of pharmacological agents, such as ligands of the translocator protein (18 kDa) (TSPO; the former peripheral benzodiazepine receptor or PBR), to locally increase the synthesis of steroids with neuroprotective and neuroregenerative properties. A concept is emerging that progesterone may exert different actions and use different signaling mechanisms in normal and injured neural tissue.
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Twede V, Tartaglia AL, Covey DF, Bamber BA. The neurosteroids dehydroepiandrosterone sulfate and pregnenolone sulfate inhibit the UNC-49 GABA receptor through a common set of residues. Mol Pharmacol 2007; 72:1322-9. [PMID: 17715402 DOI: 10.1124/mol.107.034058] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurosteroids are endogenous neuromodulators that bind and allosterically regulate GABA(A) receptors. Residues were recently identified in the first transmembrane domain (M1) of GABA(A) receptor subunits that are important for neurosteroid modulation. We are studying the inhibition of GABA(A) receptors by sulfated neurosteroids. One of these neurosteroid, pregnenolone sulfate (PS), depends on six identified M1 residues to inhibit the UNC-49 GABA receptor, a homomeric GABA receptor from Caenorhabditis elegans that is homologous to the mammalian GABA(A) receptor. Here, we investigate the inhibition of the UNC-49 GABA receptor by another sulfated neurosteroid, dehydroepiandrosterone sulfate (DHEAS). DHEAS is identical to PS except that it contains a carbonyl oxygen instead of an acetyl group at C17 on the steroid D ring. UNC-49 mutations that affect PS inhibition had broadly parallel effects on DHEAS, suggesting the two neurosteroids act through similar mechanisms. However, certain M1 mutations affected DHEAS differently than PS. Considering that first, the D ring contains the only structural difference between PS and DHEAS, and second, the strongest chemical and steric effects of a mutation are likely to be felt in the local environment of the altered residues, this result implies that the steroid D ring may contact M1 near the mutated residues. This possibility is interesting because current models of neurosteroid interactions with GABA(A) receptors, based on pregnane steroids, suggest that the steroid A ring binds M1, whereas the D ring binds M4. Our findings suggest that there may be considerable diversity in the way different classes of neurosteroids interact with GABA(A) receptors.
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Affiliation(s)
- Vernon Twede
- Department of Biological Sciences, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606-3390, USA
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Wang C, Rath NP, Covey DF. Neurosteroid Analogues. 13. Synthetic methods for the preparation of 2beta-hydroxygonane derivatives as structural mimics of ent-3alpha-hydroxysteroid modulators of GABA(A) receptors. Tetrahedron 2007; 63:7977-7984. [PMID: 18698337 DOI: 10.1016/j.tet.2007.05.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Many different 3alpha-hydroxysteroids in the androstane and pregnane steroid series enhance the actions of gamma-aminobutyric acid (GABA) at GABA type-A (GABA(A)) receptors in the mammalian central nervous system. Recent studies have shown that (3alpha,5alpha)-3-hydroxyandrostan-17-one (androsterone) is less active at these receptors than its enantiomer ent-androsterone. Further structure-activity relationship (SAR) studies are needed to explore the structural features of ent-androsterone that are important for its enhanced action at these receptors. Molecular modeling shows that 2beta-hydroxysteroids are similar in three-dimensional shape to the enantiomers of 3alpha-hydroxysteroids. The development of synthtetic methods to gain access to C(17)-substituted analogues of 2beta-hydroxygonanes for SAR studies is demonstrated with the synthesis of (2beta,5alpha,13beta,14beta)-2-hydroxygonan-17-one.
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Affiliation(s)
- Cunde Wang
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, Campus Box 8103, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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Maksay G, Fodor L, Bíró T, Avlonitis N, Calogeropoulou T. A 17beta-derivative of allopregnanolone is a neurosteroid antagonist at a cerebellar subpopulation of GABA A receptors with nanomolar affinity. Br J Pharmacol 2007; 151:1078-86. [PMID: 17558438 PMCID: PMC2042931 DOI: 10.1038/sj.bjp.0707316] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE High-affinity, subtype-selective antagonists of the neurosteroid binding sites of GABA(A) receptors are not available. We have characterized an allopregnanolone derivative as an antagonist of cerebellar GABA(A) receptors with nanomolar affinity. EXPERIMENTAL APPROACH Receptor binding and electrophysiological methods were used for the allosteric modulation of cerebellar GABA(A) receptors by an allopregnanolone derivative, (20R)-17beta-(1-hydroxy-2,3-butadienyl)-5alpha-androstane-3alpha-ol (HBAO). GABA(A) receptors of rat cerebellar membranes were labelled with the chloride channel blocker [(3)H]ethynylbicycloorthobenzoate (EBOB). The ionophore function of GABA(A) receptors was studied by whole-cell patch clamp electrophysiology in cultured rat cerebellar granule and cortical cells. KEY RESULTS Partial displacement of cerebellar [(3)H]EBOB binding by nanomolar HBAO was attenuated by 0.1 mM furosemide, an antagonist of alpha(6) and beta(2-3) subunit-containing GABA(A) receptors. Displacement curves of HBAO were reshaped by 30 nM GABA and shifted to the right. However, the micromolar potency of full displacement by allopregnanolone was not affected by 0.1 mM furosemide or 30 nM GABA. The nanomolar, but not the micromolar phase of displacement of [(3)H]EBOB binding by GABA was attenuated by 100 nM HBAO. Submicromolar HBAO did not affect [(3)H]EBOB binding to cortical and hippocampal GABA(A) receptors. HBAO up to 1 microM did not affect chloride currents elicited by 0.3-10 microM GABA, while it abolished potentiation by 1 microM allopregnanolone with nanomolar potency in cerebellar but not in cortical cells. Furosemide attenuated cerebellar inhibition by 100 nM HBAO. CONCLUSIONS AND IMPLICATIONS HBAO is a selective antagonist of allopregnanolone, a major endogenous positive modulator via neurosteroid sites of cerebellar (probably alpha(6)beta(2-3)delta) GABA(A) receptors.
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Affiliation(s)
- G Maksay
- Department of Molecular Pharmacology, Institute of Biomolecular Chemistry, Chemical Research Centre, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.
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Schumacher M, Guennoun R, Ghoumari A, Massaad C, Robert F, El-Etr M, Akwa Y, Rajkowski K, Baulieu EE. Novel perspectives for progesterone in hormone replacement therapy, with special reference to the nervous system. Endocr Rev 2007; 28:387-439. [PMID: 17431228 DOI: 10.1210/er.2006-0050] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The utility and safety of postmenopausal hormone replacement therapy has recently been put into question by large clinical trials. Their outcome has been extensively commented upon, but discussions have mainly been limited to the effects of estrogens. In fact, progestagens are generally only considered with respect to their usefulness in preventing estrogen stimulation of uterine hyperplasia and malignancy. In addition, various risks have been attributed to progestagens and their omission from hormone replacement therapy has been considered, but this may underestimate their potential benefits and therapeutic promises. A major reason for the controversial reputation of progestagens is that they are generally considered as a single class. Moreover, the term progesterone is often used as a generic one for the different types of both natural and synthetic progestagens. This is not appropriate because natural progesterone has properties very distinct from the synthetic progestins. Within the nervous system, the neuroprotective and promyelinating effects of progesterone are promising, not only for preventing but also for reversing age-dependent changes and dysfunctions. There is indeed strong evidence that the aging nervous system remains at least to some extent sensitive to these beneficial effects of progesterone. The actions of progesterone in peripheral target tissues including breast, blood vessels, and bones are less well understood, but there is evidence for the beneficial effects of progesterone. The variety of signaling mechanisms of progesterone offers exciting possibilities for the development of more selective, efficient, and safe progestagens. The recognition that progesterone is synthesized by neurons and glial cells requires a reevaluation of hormonal aging.
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Affiliation(s)
- Michael Schumacher
- INSERM UMR 788, 80, rue du Général Leclerc, 94276 Kremlin-Bicêtre, France.
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Hosie AM, Wilkins ME, Smart TG. Neurosteroid binding sites on GABA(A) receptors. Pharmacol Ther 2007; 116:7-19. [PMID: 17560657 DOI: 10.1016/j.pharmthera.2007.03.011] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Controlling neuronal excitability is vitally important for maintaining a healthy central nervous system (CNS) and this relies on the activity of type A gamma-aminobutyric acid (GABA(A)) neurotransmitter receptors. Given this role, it is therefore important to understand how these receptors are regulated by endogenous modulators in the brain and determine where they bind to the receptor. One of the most potent groups of modulators is the neurosteroids which regulate the activity of synaptic and extrasynaptic GABA(A) receptors. This level of regulation is thought to be physiologically important and its dysfunction may be relevant to numerous neurological conditions. The aim of this review is to summarise those studies that over the last 20 years have focussed upon finding the binding sites for neurosteroids on GABA(A) receptors. We consider the nature of steroid binding sites in other proteins where this has been determined at atomic resolution and how their generic features were mapped onto GABA(A) receptors to help locate 2 putative steroid binding sites. Altogether, the findings strongly suggest that neurosteroids do bind to discrete sites on the GABA(A) receptor and that these are located within the transmembrane domains of alpha and beta receptor subunits. The implications for neurosteroid binding to other inhibitory receptors such as glycine and GABA(C) receptors are also considered. Identifying neurosteroid binding sites may enable the precise pathophysiological role(s) of neurosteroids in the CNS to be established for the first time, as well as providing opportunities for the design of novel drug entities.
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Affiliation(s)
- Alastair M Hosie
- University College London, Department of Pharmacology, Gower Street, London, WC1E 6BT
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Akk G, Covey DF, Evers AS, Steinbach JH, Zorumski CF, Mennerick S. Mechanisms of neurosteroid interactions with GABA(A) receptors. Pharmacol Ther 2007; 116:35-57. [PMID: 17524487 PMCID: PMC2047817 DOI: 10.1016/j.pharmthera.2007.03.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 03/29/2007] [Indexed: 11/20/2022]
Abstract
Neuroactive steroids have some of their most potent actions by augmenting the function of GABA(A) receptors. Endogenous steroid actions on GABA(A) receptors may underlie important effects on mood and behavior. Exogenous neuroactive steroids have potential as anesthetics, anticonvulsants, and neuroprotectants. We have taken multiple approaches to understand more completely the interaction of neuroactive steroids with GABA(A) receptors. We have developed many novel steroid analogues in this effort. Recent work has resulted in synthesis of new enantiomer analogue pairs, novel ligands that probe various properties of the steroid pharmacophore, fluorescent neuroactive steroid analogues, and photoaffinity labels. Using these tools, combined with receptor binding and electrophysiological assays, we have begun to untangle the complexity of steroid actions at this important class of ligand-gated ion channel.
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Affiliation(s)
- Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Douglas F. Covey
- Department of Molecular Biology & Pharmacology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Alex S. Evers
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Molecular Biology & Pharmacology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Joe Henry Steinbach
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Anatomy & Neurobiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Charles F. Zorumski
- Department of Anatomy & Neurobiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
| | - Steven Mennerick
- Department of Anatomy & Neurobiology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
- Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110
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Eisenman LN, Shu HJ, Akk G, Wang C, Manion BD, Kress GJ, Evers AS, Steinbach JH, Covey DF, Zorumski CF, Mennerick S. Anticonvulsant and anesthetic effects of a fluorescent neurosteroid analog activated by visible light. Nat Neurosci 2007; 10:523-30. [PMID: 17322875 DOI: 10.1038/nn1862] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 02/01/2007] [Indexed: 11/08/2022]
Abstract
Most photoactivatable compounds suffer from the limitations of the ultraviolet wavelengths that are required for activation. We synthesized a neuroactive steroid analog with a fluorescent (7-nitro-2,1,3-benzoxadiazol-4-yl) amino (NBD) group in the beta configuration at the C2 position of (3alpha,5alpha)-3-hydroxypregnan-20-one (allopregnanolone, 3alpha5alphaP). Light wavelengths (480 nm) that excite compound fluorescence strongly potentiate GABAA receptor function. Potentiation is limited by photodepletion of the receptor-active species. Photopotentiation is long-lived and stereoselective and shows single-channel hallmarks similar to steroid potentiation. Other NBD-conjugated compounds also generate photopotentiation, albeit with lower potency. Thus, photopotentiation does not require a known ligand for neurosteroid potentiating sites on the GABAA receptor. Photoactivation of a membrane-impermeant, fluorescent steroid analog demonstrates that membrane localization is critical for activity. The photoactivatable steroid silences pathological spiking in cultured rat hippocampal neurons and anesthetizes tadpoles. Fluorescent steroids photoactivated by visible light may be useful for modulating GABAA receptor function in a spatiotemporally defined manner.
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Affiliation(s)
- Lawrence N Eisenman
- Department of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, Missouri 63110, USA
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Scaglione JB, Manion BD, Benz A, Taylor A, DeKoster GT, Rath NP, Evers AS, Zorumski CF, Mennerick S, Covey DF. Neurosteroid analogues. 11. Alternative ring system scaffolds: gamma-aminobutyric acid receptor modulation and anesthetic actions of benz[f]indenes. J Med Chem 2006; 49:4595-605. [PMID: 16854065 DOI: 10.1021/jm0602920] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benz[f]indenes are tricyclic compounds with a linear 6-6-5 fused carbocyclic ring system. When properly substituted, benz[f]indenes can satisfy the pharmacophore requirements of the critical hydrogen-bond donor and acceptor groups found in neuroactive steroids that modulate gamma-aminobutyric acidA (GABAA) receptor function. Thus, the benz[f]indene ring system provides an opportunity to extend the previously well-studied GABAA receptor structure-activity relationships (SAR) of neuroactive steroids to a different ring system. Depending on whether the stereochemistry of the 6-6-5 ring fusions are trans-trans or cis-trans, either planar or nonplanar benz[f]indenes are obtained. We found that the planar trans-trans benz[f]indenes are active, but less active than the steroids they were designed to mimic, whereas the nonplanar cis-trans compounds have little, if any, activity. The results provide new insight into the importance of the steroid framework for the actions of neuroactive steroids at GABAA receptors.
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Affiliation(s)
- Jamie B Scaglione
- Department of Molecular Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Schlichter R, Keller AF, De Roo M, Breton JD, Inquimbert P, Poisbeau P. Fast nongenomic effects of steroids on synaptic transmission and role of endogenous neurosteroids in spinal pain pathways. J Mol Neurosci 2006; 28:33-51. [PMID: 16632874 DOI: 10.1385/jmn:28:1:33] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 11/30/1999] [Accepted: 06/28/2005] [Indexed: 11/11/2022]
Abstract
Steroids exert long-term modulatory effects on numerous physiological functions by acting at intracellular/nuclear receptors influencing gene transcription. Steroids and neurosteroids can also rapidly modulate membrane excitability and synaptic transmission by interacting with ion channels, that is, ionotropic neurotransmitter receptors or voltage-dependent Ca2+ or K+ channels. More recently, the cloning of a plasma membrane-located G protein-coupled receptor for progestins in various species has suggested that steroids/neurosteroids could also influence second-messenger pathways by directly interacting with specific membrane receptors. Here we review the experimental evidence implicating steroids/neurosteroids in the modulation of synaptic transmission and the evidence for a role of endogenously produced neurosteroids in such modulatory effects. We present some of our recent results concerning inhibitory synaptic transmission in lamina II of the spinal cord and show that endogenous 5alpha-reduced neurosteroids are produced locally in lamina II and modulate synaptic gamma-aminobutyric acid A(GABAA) receptor function during development, as well as during inflammatory pain. The production of 5alpha-reduced neurosteroids is controlled by the endogenous activation of the peripheral benzodiazepine receptor (PBR), which initiates the first step of neurosteroidogenesis by stimulating the translocation of cholesterol across the inner mitochondrial membrane. Tonic neurosteroidogenesis observed in immature animals was decreased during postnatal development, resulting in an acceleration of GABAA receptor-mediated miniature inhibitory postsynaptic current (mIPSC) kinetics observed in the adult. Stimulation of the PBR resulted in a prolongation of GABAergic mIPSCs at all ages and was observed during inflammatory pain. Neurosteroidogenesis might play an important role in the control of nociception at least at the spinal cord level.
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Affiliation(s)
- Rémy Schlichter
- Institut des Neurosciences Cellulaires et Intégratives-Centre National de la Recherche Scientifique (CNRS), Université Louis Pasteur, 67084 Strasbourg Cedex, France.
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Fregoso-Aguilar TA, Zamudio SR. Differential effect of testosterone and repetitive induction on cataleptic and dorsal immobility in mice. Horm Behav 2006; 50:27-32. [PMID: 16473354 DOI: 10.1016/j.yhbeh.2005.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 12/08/2005] [Accepted: 12/13/2005] [Indexed: 11/16/2022]
Abstract
In nature, many species under conditions of stress (e.g., predator attack, pups carried by the mother, mating) show immobility states called "immobility responses" (IRs), which are characterized by the complete absence of movement and a relative unresponsiveness. These IR states can be induced by several kinds of sensorial stimuli. Many brain neurotransmitters from diverse cerebral areas participate in the expression of IRs. Other factors are also involved in IRs, such as learning and hormones, but at present, there is not enough experimental support about these factors. Our purpose was to investigate whether the IRs are subject to sexual hormone modulation and to examine the possible relation to learning processes. We tested the effects of acute testosterone decanoate (30 mg/kg, s.c.) and repetitive induction of two IRs; cataleptic immobility (CAT) and dorsal immobility (DI). These were tested in mice of both sexes which were either gonadectomized or sham-treated. CAT and DI were measured before and then 1 and 5 h after testosterone injection. The results show a differential effect of the repetitive induction on CAT and DI. CAT was augmented with repetition, and DI was decreased. Sex differences of the effects of the acute testosterone treatment were observed. Sham and castrated male mice showed CAT potentiation; in contrast, DI was reduced albeit only in sham male mice. Sham and ovariectomized female mice were not affected by testosterone. These results support the hypothesis that there are multiple immobility systems that can be differentially modulated by brain regions associated with processes of learning.
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Affiliation(s)
- Tomás A Fregoso-Aguilar
- Department of Physiology, National School of Biological Sciences, National Polytechnic Institute, Prolongación de Carpio y Plan de Ayala, 11340 México D.F., México
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Hirst JJ, Yawno T, Nguyen P, Walker DW. Stress in pregnancy activates neurosteroid production in the fetal brain. Neuroendocrinology 2006; 84:264-74. [PMID: 17164539 DOI: 10.1159/000097990] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 10/17/2006] [Indexed: 11/19/2022]
Abstract
Neurosteroids such as allopregnanolone are potent agonists at the GABA(A) receptor and suppress the fetal CNS activity. These steroids are synthesized in the fetal brain either from cholesterol or from circulating precursors derived from the placenta. The concentrations of allopregnanolone are remarkably high in the fetal brain and rise further in response to acute hypoxic stress, induced by constriction of the umbilical cord. This response may result from the increased 5alpha-reductase and cytochrome P-450(SCC) expression in the brain. These observations suggest that the rise in neurosteroid concentrations in response to acute hypoxia may represent an endogenous protective mechanism that reduces excitotoxicity following hypoxic stress in the developing brain. In contrast to acute stress, chronic hypoxemia induces neurosteroidogenic enzyme expression without an increase in neurosteroid concentrations and, therefore, may pose a greater risk to the fetus. At birth, the allopregnanolone concentrations in the brain fall markedly, probably due to the loss of placental precursors; however, stressors, including hypoxia and endotoxin-induced inflammation, raise allopregnanolone concentrations in the newborn brain. This may protect the newborn brain from hypoxia-induced damage. However, the rise in allopregnanolone concentrations was also associated with increased sleep. This rise in sedative steroid levels may depress arousal and contribute to the risk of sudden infant death syndrome. Our recent findings indicate that acute hypoxic stress in pregnancy initiates a neurosteroid response that may protect the fetal brain from hypoxia-induced cell death, whereas the decline in allopregnanolone levels after birth may result in greater vulnerability to brain injury in neonates.
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Affiliation(s)
- Jonathan J Hirst
- School of Biomedical Sciences, University of Newcastle, Callaghan, Australia.
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Vallée M, George O, Vitiello S, Le Moal M, Mayo W. New insights into the role of neuroactive steroids in cognitive aging. Exp Gerontol 2005; 39:1695-704. [PMID: 15582285 DOI: 10.1016/j.exger.2004.07.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Accepted: 07/07/2004] [Indexed: 01/19/2023]
Abstract
The aim of this article is to describe neuroactive steroid research that has been focused on their physiological role in cognitive aging, an attractive new field in experimental gerontology. Neuroactive steroids have been recently proposed as biomarkers of cognitive aging, however, their specific functions have not yet been fully established. For instance, data emerging from human and animal studies suggest a complex relationship between neuroactive steroids and/or metabolites and cognitive processes during aging. Thus, a better knowledge of neuroactive steroid brain distribution and function could broaden our understanding of their physiological roles and lead to novel and more effective treatments for the management of age-related brain disorders. To this end, newly developed sensitive, specific, and accurate mass spectrometry assays may allow the quantification of neuroactive steroids in discrete brain regions and greatly contribute to unravel their role in age-related cognitive deficits.
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Affiliation(s)
- M Vallée
- INSERM U588, Institut F. Magendie, 1 rue Camille Saint Saëns, Bordeaux 33077, France.
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48
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Vickers K, McNally RJ. Is premenstrual dysphoria a variant of panic disorder? A review. Clin Psychol Rev 2005; 24:933-56. [PMID: 15533279 DOI: 10.1016/j.cpr.2004.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2003] [Revised: 05/24/2004] [Accepted: 08/10/2004] [Indexed: 11/28/2022]
Abstract
Patients with premenstrual dysphoric disorder (PMDD) and patients with panic disorder (PD) both experience high rates of panic attacks in laboratory panic provocation studies. Recently, this shared elevated rate of challenge-induced panic has received increasing attention. Researchers have suggested that PMDD and panic disorder may share a pathophysiological or psychobiological link. The purpose of this paper is to review the findings from PMDD challenge studies and the theories advanced to connect PMDD to panic disorder. Taken together, the results of the PMDD challenge studies confirm that agents that incite panic in PD patients do so as well in PMDD women. This shared elevated challenge-induced panic cannot be accounted for by explanations such as a history of PD in PMDD women. None of the physiological theories as currently expressed--suffocation false alarm, gamma-aminobutyric acid (GABA), noradrenergic, serotonergic, and cholecystokinin--yet provides a compelling candidate to account for shared elevated challenge-induced panic in PD and PMDD patients. Psychological perspectives on panic emphasize that bodily sensations themselves can cause fear. Researchers have yet to apply several influential psychological approaches--conditioning, catastrophic misinterpretation, and anxiety sensitivity--to PMDD patients. Because psychological factors influence anxious responding in challenge studies, the search for the biological abnormality best accounting for PMDD panic might benefit from a reframing of the question to one that considers the psychological perspective as well.
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Affiliation(s)
- Kristin Vickers
- Department of Psychology, Harvard University, Department of Psychology, Cambridge MA 02138, USA.
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49
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Pillai GV, Smith AJ, Hunt PA, Simpson PB. Multiple structural features of steroids mediate subtype-selective effects on human α4β3δ GABAA receptors. Biochem Pharmacol 2004; 68:819-31. [PMID: 15294445 DOI: 10.1016/j.bcp.2004.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Accepted: 05/10/2004] [Indexed: 11/18/2022]
Abstract
Neurosteroids have been shown to mediate some of their physiological effects via a modulatory site on type A inhibitory gamma-aminobutyric acid (GABAA) receptors. In particular, recent evidence has implicated selective potentiation of the delta subunit of GABAA receptors as an important mediator of in vitro and in vivo neurosteroid activity. However, this has been demonstrated for only a very small number of steroids, so both the generality of this finding, and the structural features of steroids which mediate functional delta-selectivity, are unclear. We have used a potentiometric assay based on fluorescence resonance energy transfer to measure GABA-activated responses in L(tk-) cells stably transfected with human GABAA receptor alpha4beta3delta and alpha4beta3gamma2 receptor subtypes. A set of 28 steroids were evaluated on these subtypes to characterise their functional potency and efficacy in modulating GABA responses. For most compounds there was a clear separation of their efficacy profiles between the receptor subtypes, with a substantially larger maximal response at the alpha4beta3delta receptor. 5beta-Pregnan-3beta-ol-20-one, 5beta-pregnane-3alpha,20beta-diol and 5beta-pregnane-3alpha,17alpha-diol-11,20-dione showed particularly high efficacy for alpha4beta3delta. No compounds were identified that simply inhibited responses at delta-containing receptors. However, 5beta-pregnane-3alpha,17alpha,20beta-triol, prednisolone 21-acetate, 4-pregnene-17alpha,20alpha-diol-3-one-20-acetate, 4-pregnen-20alpha-ol-3-one, and 5beta-pregnane-3alpha,17alpha,21-triol-20-one inhibited, though did not abolish, GABA responses at the alpha4beta3gamma2 subtype, while evoking modest-amplitude potentiation of alpha4beta3delta responses. Molecular modelling on this compound series using principal components analysis indicates that several structural features of steroids underlie their relative functional selectivity for potentiation of delta-containing GABAA receptors.
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Affiliation(s)
- Gopalan V Pillai
- Neuroscience Research Centre, Merck Sharp and Dohme, Terlings Park, Harlow, Essex CM20 2QR, UK.
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50
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Abstract
Rho(1) receptor-channels (rho(1)Rs) are GABA-gated chloride channels that exhibit slow kinetics, little desensitization, and inert pharmacology to most anesthetics, except for neuroactive steroids (NSs). NSs differentially modulate rho(1)Rs dependent on the steric arrangement of the hydrogen atom at the fifth carbon position. In particular, the NS allotetrahydrodeoxycorticosterone (5alpha-THDOC) potentiates, whereas 5beta-pregnane-3alpha-ol-20-one (pregnanolone) and 5beta-dihydroprogesterone (5beta-DHP) inhibit rho(1) GABA currents. Here, we used Xenopus laevis oocytes expressing rho(1)Rs as a model system to study the mechanism of NS modulation. The second transmembrane residue, Ile307, was mutated to 16 amino acids. Subsequent testing of these mutants with 5alpha- and 5beta-NSs, at equivalent GABA activity, showed the following paradigm. For 5beta-DHP, Ile307 mutation either altered the degree of inhibition or entirely reversed the direction of modulation, rendering 5beta-DHP a potentiator. Dependent on the mutation, pregnanolone remained an inhibitor, transformed into a potentiator, or converted to inhibitor and potentiator based on concentration. The extent of mode reversal for both 5beta compounds showed a correlation with the side-chain hydrophilicity of the 307 residue. In contrast, Ile307 substitutions did not alter the direction of modulation for 5alpha-THDOC but caused a significant increase in the level of potentiation. Paradoxical to their impact on the mode and/or the degree of modulation, none of the mutations altered the concentration range producing the response significantly for any of the above NSs. Moreover, preincubation of Ile307 mutants with 5alpha or 5beta alone produced an equivalent effect on the activation time course. Based on the above data, a universal model is presented wherein anesthetic compounds like NSs can potentiate or inhibit the activity of ligand-gated ion channels distinct from interaction with alternative binding sites.
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Affiliation(s)
- Kendall D W Morris
- University of South Florida, College of Medicine, Department of Pharmacology, MDC Box 9, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
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