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Chintala SM, Tateiwa H, Qian M, Xu Y, Amtashar F, Chen ZW, Kirkpatrick CC, Bracamontes J, Germann AL, Akk G, Covey DF, Evers AS. Direct measurements of neurosteroid binding to specific sites on GABA A receptors. Br J Pharmacol 2024; 181:4229-4244. [PMID: 38978389 DOI: 10.1111/bph.16490] [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: 08/08/2023] [Revised: 05/12/2024] [Accepted: 05/30/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND AND PURPOSE Neurosteroids are allosteric modulators of GABAA currents, acting through several functional binding sites although their affinity and specificity for each site are unknown. The goal of this study was to measure steady-state binding affinities of various neurosteroids for specific sites on the GABAA receptor. EXPERIMENTAL APPROACH Two methods were developed to measure neurosteroid binding affinity: (1) quenching of specific tryptophan residues in neurosteroid binding sites by the neurosteroid 17-methylketone group, and (2) FRET between MQ290 (an intrinsically fluorescent neurosteroid) and tryptophan residues in the binding sites. The assays were developed using ELIC-α1GABAAR, a chimeric receptor containing transmembrane domains of the α1-GABAA receptor. Tryptophan mutagenesis was used to identify specific interactions. KEY RESULTS Allopregnanolone (3α-OH neurosteroid) was shown to bind at intersubunit and intrasubunit sites with equal affinity, whereas epi-allopregnanolone (3β-OH neurosteroid) binds at the intrasubunit site. MQ290 formed a strong FRET pair with W246, acting as a site-specific probe for the intersubunit site. The affinity and site-specificity of several neurosteroid agonists and inverse agonists was measured using the MQ290 binding assay. The FRET assay distinguishes between competitive and allosteric inhibition of MQ290 binding and demonstrated an allosteric interaction between the two neurosteroid binding sites. CONCLUSIONS AND IMPLICATIONS The affinity and specificity of neurosteroid binding to two sites in the ELIC-α1GABAAR were directly measured and an allosteric interaction between the sites was revealed. Adaptation of the MQ290 FRET assay to a plate-reader format will enable screening for high affinity agonists and antagonists for neurosteroid binding sites.
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Affiliation(s)
- Satyanarayana M Chintala
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hiroki Tateiwa
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Anesthesiology and Intensive Care Medicine, Kochi Medical School, Kochi, Japan
| | - Mingxing Qian
- Department of Developmental Biology (Pharmacology), Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yuanjian Xu
- Department of Developmental Biology (Pharmacology), Washington University School of Medicine, St. Louis, Missouri, USA
| | - Fatima Amtashar
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Zi-Wei Chen
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, Missouri, USA
| | | | - John Bracamontes
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Allison L Germann
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, Missouri, USA
| | - Douglas F Covey
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Anesthesiology and Intensive Care Medicine, Kochi Medical School, Kochi, Japan
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, Missouri, USA
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alex S Evers
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Anesthesiology and Intensive Care Medicine, Kochi Medical School, Kochi, Japan
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, Missouri, USA
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2
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Izumi Y, O’Dell KA, Cashikar AG, Paul SM, Covey DF, Mennerick SJ, Zorumski CF. Neurosteroids mediate and modulate the effects of pro-inflammatory stimulation and toll-like receptors on hippocampal plasticity and learning. PLoS One 2024; 19:e0304481. [PMID: 38875235 PMCID: PMC11178232 DOI: 10.1371/journal.pone.0304481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 05/13/2024] [Indexed: 06/16/2024] Open
Abstract
Pro-inflammatory changes contribute to multiple neuropsychiatric illnesses. Understanding how these changes are involved in illnesses and identifying strategies to alter inflammatory responses offer paths to potentially novel treatments. We previously found that acute pro-inflammatory stimulation with high (μg/ml) lipopolysaccharide (LPS) for 10-15 min dampens long-term potentiation (LTP) in the hippocampus and impairs learning. Effects of LPS involved non-canonical inflammasome signaling but were independent of toll-like receptor 4 (TLR4), a known LPS receptor. Low (ng/ml) LPS also inhibits LTP when administered for 2-4 h, and here we report that this LPS exposure requires TLR4. We also found that effects of low LPS on LTP involve the oxysterol, 25-hydroxycholesterol, akin to high LPS. Effects of high LPS on LTP are blocked by inhibiting synthesis of 5α-reduced neurosteroids, indicating that neurosteroids mediate LTP inhibition. 5α-Neurosteroids also have anti-inflammatory effects, and we found that exogenous allopregnanolone (AlloP), a key 5α-reduced steroid, prevented effects of low but not high LPS on LTP. We also found that activation of TLR2, TLR3 and TLR7 inhibited LTP and that AlloP prevented the effects of TLR2 and TLR7, but not TLR3. The enantiomer of AlloP, a steroid that has anti-inflammatory actions but low activity at GABAA receptors, prevented LTP inhibition by TLR2, TLR3 and TLR7. In vivo, both AlloP enantiomers prevented LPS-induced learning defects. These studies indicate that neurosteroids play complex roles in network effects of acute neuroinflammation and have potential importance for development of AlloP analogues as therapeutic agents.
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Affiliation(s)
- Yukitoshi Izumi
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Kazuko A. O’Dell
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Anil G. Cashikar
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Steven M. Paul
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Douglas F. Covey
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
- Developmental Biology and Anesthesiology, Washington University School of Medicine, St. Louis, MO, United States of America
- Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Steven J. Mennerick
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Charles F. Zorumski
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States of America
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, United States of America
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3
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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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4
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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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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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6
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Tateiwa H, Chintala SM, Chen Z, Wang L, Amtashar F, Bracamontes J, Germann AL, Pierce SR, Covey DF, Akk G, Evers AS. The Mechanism of Enantioselective Neurosteroid Actions on GABA A Receptors. Biomolecules 2023; 13:341. [PMID: 36830708 PMCID: PMC9953308 DOI: 10.3390/biom13020341] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 01/30/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
The neurosteroid allopregnanolone (ALLO) and pregnanolone (PREG), are equally effective positive allosteric modulators (PAMs) of GABAA receptors. Interestingly, the PAM effects of ALLO are strongly enantioselective, whereas those of PREG are not. This study was aimed at determining the basis for this difference in enantioselectivity. The oocyte electrophysiology studies showed that ent-ALLO potentiates GABA-elicited currents in α1β3 GABAA receptors with lower potency and efficacy than ALLO, PREG or ent-PREG. The small PAM effect of ent-ALLO was prevented by the α1(Q242L) mutation in the intersubunit neurosteroid binding site between the β3 and α1 subunits. Consistent with this result, neurosteroid analogue photolabeling with mass spectrometric readout, showed that ent-ALLO binds weakly to the β3-α1 intersubunit binding site in comparison to ALLO, PREG and ent-PREG. Rigid body docking predicted that ent-ALLO binds in the intersubunit site with a preferred orientation 180° different than ALLO, PREG or ent-PREG, potentially explaining its weak binding and effect. Photolabeling studies did not identify differences between ALLO and ent-ALLO binding to the α1 or β3 intrasubunit binding sites that also mediate neurosteroid modulation of GABAA receptors. The results demonstrate that differential binding of ent-ALLO and ent-PREG to the β3-α1 intersubunit site accounts for the difference in enantioselectivity between ALLO and PREG.
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Affiliation(s)
- Hiroki Tateiwa
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Anesthesiology and Intensive Care Medicine, Kochi Medical School, Kochi 7838505, Japan
| | | | - Ziwei Chen
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Taylor Institute for Innovative Psychiatric Research, St. Louis, MO 63110, USA
| | - Lei Wang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan 430074, China
| | - Fatima Amtashar
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John Bracamontes
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Allison L. Germann
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Spencer R. Pierce
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Douglas F. Covey
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Taylor Institute for Innovative Psychiatric Research, St. Louis, MO 63110, USA
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Developmental Biology (Pharmacology), Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Taylor Institute for Innovative Psychiatric Research, St. Louis, MO 63110, USA
| | - Alex S. Evers
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Taylor Institute for Innovative Psychiatric Research, St. Louis, MO 63110, USA
- Department of Developmental Biology (Pharmacology), Washington University School of Medicine, St. Louis, MO 63110, USA
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7
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Krishnan K, Qian M, Feltes M, Chen ZW, Gale S, Wang L, Sugasawa Y, Reichert DE, Schaffer JE, Ory DS, Evers AS, Covey DF. Validation of Trifluoromethylphenyl Diazirine Cholesterol Analogues As Cholesterol Mimetics and Photolabeling Reagents. ACS Chem Biol 2021; 16:1493-1507. [PMID: 34355883 DOI: 10.1021/acschembio.1c00364] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aliphatic diazirine analogues of cholesterol have been used previously to elaborate the cholesterol proteome and identify cholesterol binding sites on proteins. Cholesterol analogues containing the trifluoromethylphenyl diazirine (TPD) group have not been reported. Both classes of diazirines have been prepared for neurosteroid photolabeling studies and their combined use provided information that was not obtainable with either diazirine class alone. Hence, we prepared cholesterol TPD analogues and used them along with previously reported aliphatic diazirine analogues as photoaffinity labeling reagents to obtain additional information on the cholesterol binding sites of the pentameric Gloeobacter ligand-gated ion channel (GLIC). We first validated the TPD analogues as cholesterol substitutes and compared their actions with those of previously reported aliphatic diazirines in cell culture assays. All the probes bound to the same cholesterol binding site on GLIC but with differences in photolabeling efficiencies and residues identified. Photolabeling of mammalian (HEK) cell membranes demonstrated differences in the pattern of proteins labeled by the two classes of probes. Collectively, these date indicate that cholesterol photoaffinity labeling reagents containing an aliphatic diazirine or TPD group provide complementary information and will both be useful tools in future studies of cholesterol biology.
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8
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Sugasawa Y, Cheng WW, Bracamontes JR, Chen ZW, Wang L, Germann AL, Pierce SR, Senneff TC, Krishnan K, Reichert DE, Covey DF, Akk G, Evers AS. Site-specific effects of neurosteroids on GABA A receptor activation and desensitization. eLife 2020; 9:55331. [PMID: 32955433 PMCID: PMC7532004 DOI: 10.7554/elife.55331] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 09/20/2020] [Indexed: 12/16/2022] Open
Abstract
This study examines how site-specific binding to three identified neurosteroid-binding sites in the α1β3 GABAA receptor (GABAAR) contributes to neurosteroid allosteric modulation. We found that the potentiating neurosteroid, allopregnanolone, but not its inhibitory 3β-epimer epi-allopregnanolone, binds to the canonical β3(+)–α1(-) intersubunit site that mediates receptor activation by neurosteroids. In contrast, both allopregnanolone and epi-allopregnanolone bind to intrasubunit sites in the β3 subunit, promoting receptor desensitization and the α1 subunit promoting effects that vary between neurosteroids. Two neurosteroid analogues with diazirine moieties replacing the 3-hydroxyl (KK148 and KK150) bind to all three sites, but do not potentiate GABAAR currents. KK148 is a desensitizing agent, whereas KK150 is devoid of allosteric activity. These compounds provide potential chemical scaffolds for neurosteroid antagonists. Collectively, these data show that differential occupancy and efficacy at three discrete neurosteroid-binding sites determine whether a neurosteroid has potentiating, inhibitory, or competitive antagonist activity on GABAARs.
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Affiliation(s)
- Yusuke Sugasawa
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Wayland Wl Cheng
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - John R Bracamontes
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Zi-Wei Chen
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, United States
| | - Lei Wang
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Allison L Germann
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Spencer R Pierce
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Thomas C Senneff
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, United States
| | - David E Reichert
- Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, United States.,Department of Radiology, Washington University in St. Louis, St. Louis, United States
| | - Douglas F Covey
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, United States.,Department of Developmental Biology, Washington University in St. Louis, St. Louis, United States.,Department of Psychiatry, Washington University in St. Louis, St. Louis, United States
| | - Gustav Akk
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, United States
| | - Alex S Evers
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, United States.,Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, United States.,Department of Developmental Biology, Washington University in St. Louis, St. Louis, United States
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9
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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: 80] [Impact Index Per Article: 16.0] [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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10
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Sugasawa Y, Bracamontes JR, Krishnan K, Covey DF, Reichert DE, Akk G, Chen Q, Tang P, Evers AS, Cheng WWL. The molecular determinants of neurosteroid binding in the GABA(A) receptor. J Steroid Biochem Mol Biol 2019; 192:105383. [PMID: 31150831 PMCID: PMC6708749 DOI: 10.1016/j.jsbmb.2019.105383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/11/2019] [Accepted: 05/26/2019] [Indexed: 10/26/2022]
Abstract
Neurosteroids positively modulate GABA-A receptor (GABAAR) channel activity by binding to a transmembrane domain intersubunit site. Understanding the interactions in this site that determine neurosteroid binding and its effect is essential for the design of neurosteroid-based therapeutics. Using photo-affinity labeling and an ELIC-α1GABAAR chimera, we investigated the impact of mutations (Q242L, Q242W and W246L) within the intersubunit site on neurosteroid binding. These mutations, which abolish the thermal stabilizing effect of allopregnanolone on the chimera, reduce neither photolabeling within the intersubunit site nor competitive prevention of labeling by allopregnanolone. Instead, these mutations change the orientation of neurosteroid photolabeling. Molecular docking of allopregnanolone in WT and Q242W receptors confirms that the mutation favors re-orientation of allopregnanolone within the binding pocket. Collectively, the data indicate that mutations at Gln242 or Trp246 that eliminate neurosteroid effects do not eliminate neurosteroid binding within the intersubunit site, but significantly alter the preferred orientation of the neurosteroid within the site. The interactions formed by Gln242 and Trp246 within this pocket play a vital role in determining the orientation of the neurosteroid that may be necessary for its functional effect.
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Affiliation(s)
- Yusuke Sugasawa
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - John R Bracamontes
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Douglas F Covey
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA; Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA; Department of Psychiatry, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - David E Reichert
- Department of Radiology, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Gustav Akk
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Qiang Chen
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
| | - Pei Tang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
| | - Alex S Evers
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA; Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Wayland W L Cheng
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO 63110, USA.
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11
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Chen ZW, Bracamontes JR, Budelier MM, Germann AL, Shin DJ, Kathiresan K, Qian MX, Manion B, Cheng WWL, Reichert DE, Akk G, Covey DF, Evers AS. Multiple functional neurosteroid binding sites on GABAA receptors. PLoS Biol 2019; 17:e3000157. [PMID: 30845142 PMCID: PMC6424464 DOI: 10.1371/journal.pbio.3000157] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 03/19/2019] [Accepted: 02/05/2019] [Indexed: 11/18/2022] Open
Abstract
Neurosteroids are endogenous modulators of neuronal excitability and nervous system development and are being developed as anesthetic agents and treatments for psychiatric diseases. While gamma amino-butyric acid Type A (GABAA) receptors are the primary molecular targets of neurosteroid action, the structural details of neurosteroid binding to these proteins remain ill defined. We synthesized neurosteroid analogue photolabeling reagents in which the photolabeling groups were placed at three positions around the neurosteroid ring structure, enabling identification of binding sites and mapping of neurosteroid orientation within these sites. Using middle-down mass spectrometry (MS), we identified three clusters of photolabeled residues representing three distinct neurosteroid binding sites in the human α1β3 GABAA receptor. Novel intrasubunit binding sites were identified within the transmembrane helical bundles of both the α1 (labeled residues α1-N408, Y415) and β3 (labeled residue β3-Y442) subunits, adjacent to the extracellular domains (ECDs). An intersubunit site (labeled residues β3-L294 and G308) in the interface between the β3(+) and α1(−) subunits of the GABAA receptor pentamer was also identified. Computational docking studies of neurosteroid to the three sites predicted critical residues contributing to neurosteroid interaction with the GABAA receptors. Electrophysiological studies of receptors with mutations based on these predictions (α1-V227W, N408A/Y411F, and Q242L) indicate that both the α1 intrasubunit and β3-α1 intersubunit sites are critical for neurosteroid action. Novel neurosteroid analogue photolabeling reagents identify three specific neurosteroid binding sites on α1β3 GABAA receptors, showing that a site between the α and β subunits, as well as a site within the α-subunit, contribute to neurosteroid-mediated enhancement of GABAA currents. Neurosteroids are cholesterol metabolites produced by neurons and glial cells that participate in central nervous system (CNS) development, regulate neuronal excitability, and modulate complex behaviors such as mood. Exogenously administered neurosteroid analogues are effective sedative hypnotics and are being developed as antidepressants and anticonvulsants. Gamma amino-butyric acid Type A (GABAA) receptors, the principal ionotropic inhibitory neurotransmitter receptors in the brain, are the primary functional target of neurosteroids. Understanding the molecular details of neurosteroid interactions with GABAA receptors is critical to understanding their mechanism of action and developing specific and effective therapeutic agents. In the current study, we developed a suite of neurosteroid analogue affinity labeling reagents, which we used to identify three distinct binding sites on GABAA receptors and to determine the orientation of neurosteroid binding in each site. Electrophysiological studies performed on receptors with mutations designed to disrupt the identified binding sites showed that two of the three sites contribute to neurosteroid modulation of GABAA currents. The distinct patterns of neurosteroid affinity, binding orientation, and effect provide the potential for the development of isoform-specific agonists, partial agonists, and antagonists with targeted therapeutic effects.
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Affiliation(s)
- Zi-Wei Chen
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America.,Taylor Family Institute for Innovative Psychiatric Research, St Louis, Missouri, United States of America
| | - John R Bracamontes
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Melissa M Budelier
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Allison L Germann
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Daniel J Shin
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Krishnan Kathiresan
- Department of Developmental Biology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Ming-Xing Qian
- Department of Developmental Biology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Brad Manion
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Wayland W L Cheng
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - David E Reichert
- Taylor Family Institute for Innovative Psychiatric Research, St Louis, Missouri, United States of America.,Department of Radiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Gustav Akk
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Douglas F Covey
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America.,Taylor Family Institute for Innovative Psychiatric Research, St Louis, Missouri, United States of America.,Department of Developmental Biology, Washington University in St Louis, St Louis, Missouri, United States of America
| | - Alex S Evers
- Department of Anesthesiology, Washington University in St Louis, St Louis, Missouri, United States of America.,Taylor Family Institute for Innovative Psychiatric Research, St Louis, Missouri, United States of America.,Department of Developmental Biology, Washington University in St Louis, St Louis, Missouri, United States of America
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12
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Ratner MH, Kumaresan V, Farb DH. Neurosteroid Actions in Memory and Neurologic/Neuropsychiatric Disorders. Front Endocrinol (Lausanne) 2019; 10:169. [PMID: 31024441 PMCID: PMC6465949 DOI: 10.3389/fendo.2019.00169] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/28/2019] [Indexed: 12/24/2022] Open
Abstract
Memory dysfunction is a symptomatic feature of many neurologic and neuropsychiatric disorders; however, the basic underlying mechanisms of memory and altered states of circuitry function associated with disorders of memory remain a vast unexplored territory. The initial discovery of endogenous neurosteroids triggered a quest to elucidate their role as neuromodulators in normal and diseased brain function. In this review, based on the perspective of our own research, the advances leading to the discovery of positive and negative neurosteroid allosteric modulators of GABA type-A (GABAA), NMDA, and non-NMDA type glutamate receptors are brought together in a historical and conceptual framework. We extend the analysis toward a state-of-the art view of how neurosteroid modulation of neural circuitry function may affect memory and memory deficits. By aggregating the results from multiple laboratories using both animal models for disease and human clinical research on neuropsychiatric and age-related neurodegenerative disorders, elements of a circuitry level view begins to emerge. Lastly, the effects of both endogenously active and exogenously administered neurosteroids on neural networks across the life span of women and men point to a possible underlying pharmacological connectome by which these neuromodulators might act to modulate memory across diverse altered states of mind.
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13
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Chen DM, Ziolkowski L, Benz A, Qian M, Zorumski CF, Covey DF, Mennerick S. A Clickable Oxysterol Photolabel Retains NMDA Receptor Activity and Accumulates in Neurons. Front Neurosci 2018; 12:923. [PMID: 30574068 PMCID: PMC6291516 DOI: 10.3389/fnins.2018.00923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/23/2018] [Indexed: 01/22/2023] Open
Abstract
Oxysterol analogs that modulate NMDA receptor function are candidates for therapeutic development to treat neuropsychiatric disorders. However, the cellular actions of these compounds are still unclear. For instance, how these compounds are compartmentalized or trafficked in neurons is unknown. In this study, we utilized a chemical biology approach combining photolabeling and click chemistry. We introduce a biologically active oxysterol analog that contains: (1) a diazirine group, allowing for the permanent labeling of cellular targets, and (2) an alkyne group, allowing for subsequent in situ visualization using Cu2+ catalyzed cycloaddition of an azide-conjugated fluorophore. The physiological properties of this analog at NMDA receptors resemble those of other oxysterols, including occlusion with other oxysterol-like compounds. Fluorescent imaging reveals that the analog accumulates diffusely in the cytoplasm of neurons through an energy-independent mechanism. Overall, this work introduces a novel chemical biology approach to investigate oxysterol actions and introduces a tool useful for further cell biological and biochemical studies of oxysterols.
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Affiliation(s)
- Daniel M Chen
- Department of Psychiatry, Washington University, St. Louis, MO, United States
| | - Luke Ziolkowski
- Department of Psychiatry, Washington University, St. Louis, MO, United States
| | - Ann Benz
- Department of Psychiatry, Washington University, St. Louis, MO, United States.,Taylor Family Institute for Innovative Psychiatric Research, St. Louis, MO, United States
| | - Mingxing Qian
- Department of Developmental Biology, Washington University, St. Louis MO, United States
| | - Charles F Zorumski
- Department of Psychiatry, Washington University, St. Louis, MO, United States.,Taylor Family Institute for Innovative Psychiatric Research, St. Louis, MO, United States
| | - Douglas F Covey
- Taylor Family Institute for Innovative Psychiatric Research, St. Louis, MO, United States.,Department of Developmental Biology, Washington University, St. Louis MO, United States
| | - Steven Mennerick
- Department of Psychiatry, Washington University, St. Louis, MO, United States.,Taylor Family Institute for Innovative Psychiatric Research, St. Louis, MO, United States
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14
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Chisari M, Wilding TJ, Brunwasser S, Krishnan K, Qian M, Benz A, Huettner JE, Zorumski CF, Covey DF, Mennerick S. Visualizing pregnenolone sulfate-like modulators of NMDA receptor function reveals intracellular and plasma-membrane localization. Neuropharmacology 2018; 144:91-103. [PMID: 30332607 DOI: 10.1016/j.neuropharm.2018.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 09/07/2018] [Accepted: 10/12/2018] [Indexed: 12/27/2022]
Abstract
Positive modulators of NMDA receptors are important candidates for therapeutic development to treat psychiatric disorders including autism and schizophrenia. Sulfated neurosteroids have been studied as positive allosteric modulators of NMDA receptors for years, but we understand little about the cellular fate of these compounds, an important consideration for drug development. Here we focus on a visualizable sulfated neurosteroid analogue, KK-169. As expected of a pregnenolone sulfate analogue, the compound strongly potentiates NMDA receptor function, is an antagonist of GABAA receptors, exhibits occlusion with pregnenolone sulfate potentiation, and requires receptor domains important for pregnenolone sulfate potentiation. KK-169 exhibits somewhat higher potency than the natural parent, pregnenolone sulfate. The analogue contains a side-chain alkyne group, which we exploited for retrospective click labeling of neurons. Although the anionic sulfate group is expected to hinder cell entry, we detected significant accumulation of KK-169 in neurons with even brief incubations. Adding a photolabile diazirine group revealed that the expected plasma membrane localization of KK-169 is likely lost during fixation. Overall, our studies reveal new facets of the structure-activity relationship of neurosteroids at NMDA receptors, and their intracellular distribution suggests that sulfated neurosteroids could have unappreciated targets in addition to plasma membrane receptors.
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Affiliation(s)
- Mariangela Chisari
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Timothy J Wilding
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Samuel Brunwasser
- Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO, USA
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Mingxing Qian
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Ann Benz
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - James E Huettner
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA; 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; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO, USA.
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15
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Ge SS, Chen B, Wu YY, Long QS, Zhao YL, Wang PY, Yang S. Current advances of carbene-mediated photoaffinity labeling in medicinal chemistry. RSC Adv 2018; 8:29428-29454. [PMID: 35547988 PMCID: PMC9084484 DOI: 10.1039/c8ra03538e] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/07/2018] [Indexed: 12/21/2022] Open
Abstract
Photoaffinity labeling (PAL) in combination with a chemical probe to covalently bind its target upon UV irradiation has demonstrated considerable promise in drug discovery for identifying new drug targets and binding sites. In particular, carbene-mediated photoaffinity labeling (cmPAL) has been widely used in drug target identification owing to its excellent photolabeling efficiency, minimal steric interference and longer excitation wavelength. Specifically, diazirines, which are among the precursors of carbenes and have higher carbene yields and greater chemical stability than diazo compounds, have proved to be valuable photolabile reagents in a diverse range of biological systems. This review highlights current advances of cmPAL in medicinal chemistry, with a focus on structures and applications for identifying small molecule-protein and macromolecule-protein interactions and ligand-gated ion channels, coupled with advances in the discovery of targets and inhibitors using carbene precursor-based biological probes developed in recent decades.
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Affiliation(s)
- Sha-Sha Ge
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Biao Chen
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Yuan-Yuan Wu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Qing-Su Long
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Yong-Liang Zhao
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Pei-Yi Wang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals of Guizhou University Guiyang 550025 China +86-851-8829-2170 +86-851-8829-2171
- College of Pharmacy, East China University of Science & Technology Shanghai 200237 China
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16
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Abstract
Human studies examining the effects of the dissociative anesthetic ketamine as a model for psychosis and as a rapidly acting antidepressant have spurred great interest in understanding ketamine's actions at molecular, cellular, and network levels. Although ketamine has unequivocal uncompetitive inhibitory effects on N-methyl-d-aspartate receptors (NMDARs) and may preferentially alter the function of NMDARs on interneurons, recent work has questioned whether block of NMDARs is critical for its mood enhancing actions. In this viewpoint, we examine the evolving literature on ketamine supporting NMDARs as important triggers for certain psychiatric effects and the possibility that the antidepressant trigger is unrelated to NMDARs. The rapidly evolving story of ketamine offers great hope for untangling and treating the biology of both depressive and psychotic illnesses.
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17
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Budelier MM, Cheng WWL, Bergdoll L, Chen ZW, Abramson J, Krishnan K, Qian M, Covey DF, Janetka JW, Evers AS. Click Chemistry Reagent for Identification of Sites of Covalent Ligand Incorporation in Integral Membrane Proteins. Anal Chem 2017; 89:2636-2644. [PMID: 28194953 DOI: 10.1021/acs.analchem.6b05003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Identifying sites of protein-ligand interaction is important for structure-based drug discovery and understanding protein structure-function relationships. Mass spectrometry (MS) has emerged as a useful tool for identifying residues covalently modified by ligands. Current methods use database searches that are dependent on acquiring interpretable fragmentation spectra (MS2) of peptide-ligand adducts. This is problematic for identifying sites of hydrophobic ligand incorporation in integral membrane proteins (IMPs), where poor aqueous solubility and ionization of peptide-ligand adducts and collision-induced adduct loss hinder the acquisition of quality MS2 spectra. To address these issues, we developed a fast ligand identification (FLI) tag that can be attached to any alkyne-containing ligand via Cu(I)-catalyzed cycloaddition. The FLI tag adds charge to increase solubility and ionization, and utilizes stable isotope labeling for MS1 level identification of hydrophobic peptide-ligand adducts. The FLI tag was coupled to an alkyne-containing neurosteroid photolabeling reagent and used to identify peptide-steroid adducts in MS1 spectra via the stable heavy isotope pair. Peptide-steroid adducts were not identified in MS2-based database searches because collision-induced adduct loss was the dominant feature of collision-induced dissociation (CID) fragmentation, but targeted analysis of MS1 pairs using electron transfer dissociation (ETD) markedly reduced adduct loss. Using the FLI tag and ETD, we identified Glu73 as the site of photoincorporation of our neurosteroid ligand in the IMP, mouse voltage-dependent anion channel-1 (mVDAC1), and top-down MS confirmed a single site of photolabeling.
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Affiliation(s)
- Melissa M Budelier
- Department of Anesthesiology, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Wayland W L Cheng
- Department of Anesthesiology, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles , Los Angeles, California 90095, United States
| | - Zi-Wei Chen
- Department of Anesthesiology, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,The Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles , Los Angeles, California 90095, United States.,The Institute for Stem Cell Biology and Regenerative Medicine (instem), National Centre for Biological Sciences-Tata Institute of Fundamental Research , Bangalore 560065, Karnataka India
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Mingxing Qian
- Department of Developmental Biology, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Douglas F Covey
- Department of Anesthesiology, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,The Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,Department of Developmental Biology, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,Department of Psychiatry, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - James W Janetka
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis , St. Louis, Missouri 63110, United States
| | - Alex S Evers
- Department of Anesthesiology, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,The Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis , St. Louis, Missouri 63110, United States.,Department of Developmental Biology, Washington University in St. Louis , St. Louis, Missouri 63110, United States
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