1
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Griem-Krey N, Clarkson AN, Wellendorph P. CaMKIIα as a Promising Drug Target for Ischemic Grey Matter. Brain Sci 2022; 12:1639. [PMID: 36552099 PMCID: PMC9775128 DOI: 10.3390/brainsci12121639] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/26/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a major mediator of Ca2+-dependent signaling pathways in various cell types throughout the body. Its neuronal isoform CaMKIIα (alpha) centrally integrates physiological but also pathological glutamate signals directly downstream of glutamate receptors and has thus emerged as a target for ischemic stroke. Previous studies provided evidence for the involvement of CaMKII activity in ischemic cell death by showing that CaMKII inhibition affords substantial neuroprotection. However, broad inhibition of this central kinase is challenging because various essential physiological processes like synaptic plasticity rely on intact CaMKII regulation. Thus, specific strategies for targeting CaMKII after ischemia are warranted which would ideally only interfere with pathological activity of CaMKII. This review highlights recent advances in the understanding of how ischemia affects CaMKII and how pathospecific pharmacological targeting of CaMKII signaling could be achieved. Specifically, we discuss direct targeting of CaMKII kinase activity with peptide inhibitors versus indirect targeting of the association (hub) domain of CaMKIIα with analogues of γ-hydroxybutyrate (GHB) as a potential way to achieve more specific pharmacological modulation of CaMKII activity after ischemia.
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Affiliation(s)
- Nane Griem-Krey
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Andrew N. Clarkson
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9016, New Zealand
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
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2
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Tian Y, Shehata MA, Gauger SJ, Veronesi C, Hamborg L, Thiesen L, Bruus-Jensen J, Royssen JS, Leurs U, Larsen ASG, Krall J, Solbak SM, Wellendorph P, Frølund B. Exploring the NCS-382 Scaffold for CaMKIIα Modulation: Synthesis, Biochemical Pharmacology, and Biophysical Characterization of Ph-HTBA as a Novel High-Affinity Brain-Penetrant Stabilizer of the CaMKIIα Hub Domain. J Med Chem 2022; 65:15066-15084. [DOI: 10.1021/acs.jmedchem.2c00805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yongsong Tian
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Mohamed A. Shehata
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Stine Juul Gauger
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Carolina Veronesi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Louise Hamborg
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Louise Thiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jesper Bruus-Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Johanne Schlieper Royssen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Ulrike Leurs
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Anne Sofie G. Larsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Sara M.Ø. Solbak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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3
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Tian Y, Shehata MA, Gauger SJ, Ng CKL, Solbak S, Thiesen L, Bruus-Jensen J, Krall J, Bundgaard C, Gibson KM, Wellendorph P, Frølund B. Discovery and Optimization of 5-Hydroxy-Diclofenac toward a New Class of Ligands with Nanomolar Affinity for the CaMKIIα Hub Domain. J Med Chem 2022; 65:6656-6676. [PMID: 35500061 DOI: 10.1021/acs.jmedchem.1c02177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Ca2+/calmodulin-dependent protein kinase II α (CaMKIIα) is a brain-relevant kinase involved in long-term potentiation and synaptic plasticity. We have recently pinpointed the CaMKIIα hub domain as the long-sought-after high-affinity target of γ-hydroxybutyrate ligands substantiated with a high-resolution cocrystal of 5-hydroxydiclofenac (3). Herein, we employed in silico approaches to rationalize and guide the synthesis and pharmacological characterization of a new series of analogues circumventing chemical stability problems associated with 3. The oxygen-bridged analogue 4d showed mid-nanomolar affinity and notable ligand-induced stabilization effects toward the CaMKIIα hub oligomer. Importantly, 4d displayed superior chemical and metabolic stability over 3 by showing excellent chemical stability in phosphate-buffered saline and high resistance to form reactive intermediates and subsequent sulfur conjugates. Altogether, our study highlights 4d as a new CaMKIIα hub high-affinity ligand with enhanced pharmacokinetic properties, representing a powerful tool compound for allosteric regulation of kinase activity with subtype specificity.
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Affiliation(s)
- Yongsong Tian
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Mohamed A Shehata
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Stine Juul Gauger
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Clarissa K L Ng
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Sara Solbak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Louise Thiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jesper Bruus-Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | | | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington 99202, United States
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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4
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GHB analogs confer neuroprotection through specific interaction with the CaMKIIα hub domain. Proc Natl Acad Sci U S A 2021; 118:2108079118. [PMID: 34330837 PMCID: PMC8346900 DOI: 10.1073/pnas.2108079118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
GHB is a natural brain metabolite of GABA, previously reported to be neuroprotective. However, the high-affinity binding site for GHB has remained elusive for almost 40 y. We here unveil CaMKIIα, a highly important neuronal kinase, as the long-sought-after GHB high-affinity target. Via a specific interaction within the central hub domain of CaMKIIα, GHB analogs act to stabilize the hub oligomer complex. This interaction potentially explains pronounced neuroprotective effects of GHB analogs in cultured neurons exposed to a chemical insult and in mice exposed to ischemia. The postischemic treatment effects of GHB analogs underline these compounds as selective and high-affinity potential drug candidates and CaMKIIα as a relevant pharmacological target for stroke therapy. Ca2+/calmodulin-dependent protein kinase II alpha subunit (CaMKIIα) is a key neuronal signaling protein and an emerging drug target. The central hub domain regulates the activity of CaMKIIα by organizing the holoenzyme complex into functional oligomers, yet pharmacological modulation of the hub domain has never been demonstrated. Here, using a combination of photoaffinity labeling and chemical proteomics, we show that compounds related to the natural substance γ-hydroxybutyrate (GHB) bind selectively to CaMKIIα. By means of a 2.2-Å x-ray crystal structure of ligand-bound CaMKIIα hub, we reveal the molecular details of the binding site deep within the hub. Furthermore, we show that binding of GHB and related analogs to this site promotes concentration-dependent increases in hub thermal stability believed to alter holoenzyme functionality. Selectively under states of pathological CaMKIIα activation, hub ligands provide a significant and sustained neuroprotection, which is both time and dose dependent. This is demonstrated in neurons exposed to excitotoxicity and in a mouse model of cerebral ischemia with the selective GHB analog, HOCPCA (3-hydroxycyclopent-1-enecarboxylic acid). Together, our results indicate a hitherto unknown mechanism for neuroprotection by a highly specific and unforeseen interaction between the CaMKIIα hub domain and small molecule brain-penetrant GHB analogs. This establishes GHB analogs as powerful tools for investigating CaMKII neuropharmacology in general and as potential therapeutic compounds for cerebral ischemia in particular.
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5
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Griem‐Krey N, Frølund B, Marek A, Wellendorph P. Radiolabeled HOCPCA as a highly useful tool in drug discovery and pharmacology. J Labelled Comp Radiopharm 2020. [DOI: 10.1002/jlcr.3870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nane Griem‐Krey
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Prague Czech Republic
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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6
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Thiesen L, Belew ZM, Griem-Krey N, Pedersen SF, Crocoll C, Nour-Eldin HH, Wellendorph P. The γ-hydroxybutyric acid (GHB) analogue NCS-382 is a substrate for both monocarboxylate transporters subtypes 1 and 4. Eur J Pharm Sci 2020; 143:105203. [PMID: 31866563 DOI: 10.1016/j.ejps.2019.105203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/11/2019] [Accepted: 12/19/2019] [Indexed: 11/20/2022]
Abstract
The small-molecule ligand (E)-2-(5-hydroxy-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-ylidene)acetic acid (NCS-382) is an analogue of γ-hydroxybutyric acid (GHB) and is widely used for probing the brain-specific GHB high-affinity binding sites. To reach these, brain uptake is imperative, and it is therefore important to understand the molecular mechanisms of NCS-382 transport in order to direct in vivo studies. In this study, we hypothesized that NCS-382 is a substrate for the monocarboxylate transporter subtype 1 (MCT1) which is known to mediate blood-brain barrier (BBB) permeation of GHB. For this purpose, we investigated NCS-382 uptake by MCT subtypes endogenously expressed in tsA201 and MDA-MB-231 cell lines in assays of radioligand-based competition and fluorescence-based intracellular pH measurements. To further verify the results, we measured NCS-382 uptake by means of mass spectrometry in Xenopus laevis oocytes heterologously expressing MCT subtypes. As expected, we found that NCS-382 is a substrate for MCT1 with half-maximal effective concentrations in the low millimolar range. Surprisingly, NCS-382 also showed substrate activity at MCT4 as well as uptake in water-injected oocytes, suggesting a component of passive diffusion. In conclusion, transport of NCS-382 across membranes differs from GHB as it also involves MCT4 and/or passive diffusion. This should be taken into consideration when designing pharmacological studies with this compound and its closely related analogues. The combination of MCT assays used here exemplifies a setup that may be suitable for a reliable characterization of MCT ligands in general.
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Affiliation(s)
- Louise Thiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zeinu Mussa Belew
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Nane Griem-Krey
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen Ø, Denmark
| | - Christoph Crocoll
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Hussam Hassan Nour-Eldin
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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7
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Doubková S, Marek A. Frustrated Lewis pairs: A real alternative to deuteride/tritide reductions. J Labelled Comp Radiopharm 2019; 62:729-742. [PMID: 31170318 DOI: 10.1002/jlcr.3774] [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: 03/29/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 11/11/2022]
Abstract
Deuterium- and tritium-labeled compounds play a principal role in tracing of biologically active molecules in complicated biochemical systems. The state-of-the-art techniques using noble metal catalysts or strong reducing agents often suffers from low functional group tolerances, poor selectivity, tricky or multistep synthesis of reagents, and low specific activity of the labeled product. Herein, we demonstrate a mild and nonmetallic technique of deuteration and tritiation of polarized double bonds, such as carbonyl compounds, yielding labeled alcohols of high specific activities. This one-pot synthesis uses carrier-free hydrogen gas in situ activated by a freshly prepared frustrated Lewis pair, generating reducing reagents. This labeling strategy shows better selectivity and functional group tolerances compared with current reductive methods. Reported is an example of the selective reduction of the aldehyde moiety of 3-acetylbenzaldehyde. What makes this technology groundbreaking is its mildness, selectivity, and generation of limited amount of radioactive waste as almost no byproducts were generated after use of (B(C6 F5 )3 3 H)(3 HTMP) reducing reagent. Radiochemical purity of desired 3 H-labeled product in a crude reaction mixture was determined of over 94%. This work provides, to the community of radiochemists, a practical protocol for frustrated Lewis pairs (FLP)-assisted deuterium/tritium labeling technology.
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Affiliation(s)
- Sabina Doubková
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Marek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
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8
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Krall J, Bavo F, Falk-Petersen CB, Jensen CH, Nielsen JO, Tian Y, Anglani V, Kongstad KT, Piilgaard L, Nielsen B, Gloriam DE, Kehler J, Jensen AA, Harpsøe K, Wellendorph P, Frølund B. Discovery of 2-(Imidazo[1,2-b]pyridazin-2-yl)acetic Acid as a New Class of Ligands Selective for the γ-Hydroxybutyric Acid (GHB) High-Affinity Binding Sites. J Med Chem 2019; 62:2798-2813. [DOI: 10.1021/acs.jmedchem.9b00131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Francesco Bavo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
- Department of Pharmaceutical Sciences, University of Milan, via Mangiagalli 25, 20133 Milano, Italy
| | - Christina B. Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Claus H. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Julie O. Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Yongsong Tian
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Valeria Anglani
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kenneth T. Kongstad
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Louise Piilgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - David E. Gloriam
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jan Kehler
- Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, DK-2500 Valby, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kasper Harpsøe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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9
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Thiesen L, Frølund B, Wellendorph P. Lack of evidence for synaptic high-affinity γ-hydroxybutyric acid (GHB) transport in rat brain synaptosomes and 11 Na + -dependent SLC neurotransmitter transporters. J Neurochem 2018; 149:195-210. [PMID: 30570143 DOI: 10.1111/jnc.14649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 01/14/2023]
Abstract
γ-Hydroxybutyric acid (GHB) is an endogenous compound proposed to act as a neurotransmitter. Na+ -dependent, high-affinity GHB transport has long been considered important evidence supporting this hypothesis. However, the molecular identity of such a high-affinity transporter remains unknown. In this study, we sought to identify and characterize GHB synaptic transport through a series of studies using both native and recombinant systems with the ultimate aim of providing evidence to clarify the proposed role of GHB as a neurotransmitter in the mammalian brain. Native [3 H]GHB transport was studied in isolated rat brain synaptosomes and compared to synaptic membranes. As a targeted approach, GHB was also screened against a panel of Na+ -dependent SLC6 neurotransmitter transporters recombinantly expressed in Xenopus laevis oocytes or tsA201 cells. Finally, the low-affinity GHB transporters, MCT1/2 and SMCT1, were probed as GHB transporters in L-[14 C]lactate uptake assays in synaptosomes. We found no evidence of high-affinity [3 H]GHB transport in purified rat brain cortical or striatal synaptosomes or at any of the 11 SLC6 transporters tested. Instead, our results indicate the binding of [3 H]GHB to an unidentified membrane component, distinct from any of the known GHB targets. In accordance with others, we found that GHB and the analog 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) can, in millimolar concentrations, inhibit L-[14 C]lactate uptake at MCT1 and/or MCT2 and that this also can occur in synaptosomes. In conclusion, through a variety of in vitro pharmacological studies, we were unsuccessful in identifying a specific synaptic high-affinity transporter for GHB. Our findings emphasize the need to reevaluate GHB's role as a potential neurotransmitter. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Louise Thiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Vogel KR, Ainslie GR, Walters DC, McConnell A, Dhamne SC, Rotenberg A, Roullet JB, Gibson KM. Succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism: an update on pharmacological and enzyme-replacement therapeutic strategies. J Inherit Metab Dis 2018; 41:699-708. [PMID: 29460030 PMCID: PMC6041169 DOI: 10.1007/s10545-018-0153-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 12/16/2022]
Abstract
We present an update to the status of research on succinic semialdehyde dehydrogenase (SSADH) deficiency (SSADHD), a rare disorder of GABA metabolism. This is an unusual disorder featuring the accumulation of both GABA and its neuromodulatory analog, gamma-hydroxybutyric acid (GHB), and recent studies have advanced the potential clinical application of NCS-382, a putative GHB receptor antagonist. Animal studies have provided proof-of-concept that enzyme replacement therapy could represent a long-term therapeutic option. The characterization of neuronal stem cells (NSCs) derived from aldehyde dehydrogenase 5a1-/- (aldh5a1-/-) mice, the murine model of SSADHD, has highlighted NSC utility as an in vitro system in which to study therapeutics and associated toxicological properties. Gene expression analyses have revealed that transcripts encoding GABAA receptors are down-regulated and may remain largely immature in aldh5a1-/- brain, characterized by excitatory as opposed to inhibitory outputs, the latter being the expected action in the mature central nervous system. This indicates that agents altering chloride channel activity may be therapeutically relevant in SSADHD. The most recent therapeutic prospects include mTOR (mechanistic target of rapamycin) inhibitors, drugs that have received attention with the elucidation of the effects of elevated GABA on autophagy. The outlook for novel therapeutic trials in SSADHD continues to improve.
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Affiliation(s)
- Kara R Vogel
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | | | - Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | | | - Sameer C Dhamne
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA.
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11
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Krall J, Jensen CH, Bavo F, Falk-Petersen CB, Haugaard AS, Vogensen SB, Tian Y, Nittegaard-Nielsen M, Sigurdardóttir SB, Kehler J, Kongstad KT, Gloriam DE, Clausen RP, Harpsøe K, Wellendorph P, Frølund B. Molecular Hybridization of Potent and Selective γ-Hydroxybutyric Acid (GHB) Ligands: Design, Synthesis, Binding Studies, and Molecular Modeling of Novel 3-Hydroxycyclopent-1-enecarboxylic Acid (HOCPCA) and trans-γ-Hydroxycrotonic Acid (T-HCA) Analogs. J Med Chem 2017; 60:9022-9039. [DOI: 10.1021/acs.jmedchem.7b01351] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacob Krall
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Claus Hatt Jensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Francesco Bavo
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Department
of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy
| | - Christina Birkedahl Falk-Petersen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Anne Stæhr Haugaard
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Stine Byskov Vogensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yongsong Tian
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Mia Nittegaard-Nielsen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Sara Björk Sigurdardóttir
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Jan Kehler
- Discovery
Chemistry, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | - Kenneth Thermann Kongstad
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - David E. Gloriam
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Rasmus Prætorius Clausen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Kasper Harpsøe
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Bente Frølund
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
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12
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Jensen CH, Hansen HD, Bay T, Vogensen SB, Lehel S, Thiesen L, Bundgaard C, Clausen RP, Knudsen GM, Herth MM, Wellendorph P, Frølund B. Radiosynthesis and Evaluation of [ 11C]3-Hydroxycyclopent-1-enecarboxylic Acid as Potential PET Ligand for the High-Affinity γ-Hydroxybutyric Acid Binding Sites. ACS Chem Neurosci 2017; 8:22-27. [PMID: 28095676 DOI: 10.1021/acschemneuro.6b00335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
γ-Hydroxybutyric acid (GHB) is an endogenous neuroactive substance and proposed neurotransmitter with affinity for both low- and high-affinity binding sites. A radioligand with high and specific affinity toward the high-affinity GHB binding site would be a unique tool toward a more complete understanding of this population of binding sites. With its high specific affinity and monocarboxylate transporter (MCT1) mediated transport across the blood-brain barrier in pharmacological doses, 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) seems like a suitable PET radiotracer candidate. Here, we report the 11C-labeling and subsequent evaluation of [11C]HOCPCA in a domestic pig, as a PET-radioligand for visualization of the high-affinity GHB binding sites in the live pig brain. To investigate the regional binding of HOCPCA in pig brain prior to in vivo PET studies, in vitro quantitative autoradiography on sections of pig brain was performed using [3H]HOCPCA. In vivo evaluation of [11C]HOCPCA showed no brain uptake, possibly due to a limited uptake of HOCPCA by the MCT1 transporter at tracer doses of [11C]HOCPCA.
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Affiliation(s)
- Claus H. Jensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Hanne D. Hansen
- Neurobiology
Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Tina Bay
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Stine B. Vogensen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Szabolcs Lehel
- PET
and Cyclotron Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Louise Thiesen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | - Rasmus P. Clausen
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Gitte M. Knudsen
- Neurobiology
Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Matthias M. Herth
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
- Neurobiology
Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100 Copenhagen, Denmark
- PET
and Cyclotron Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Petrine Wellendorph
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bente Frølund
- Department
of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
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13
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Kamal RM, van Noorden MS, Wannet W, Beurmanjer H, Dijkstra BAG, Schellekens A. Pharmacological Treatment in γ-Hydroxybutyrate (GHB) and γ-Butyrolactone (GBL) Dependence: Detoxification and Relapse Prevention. CNS Drugs 2017; 31:51-64. [PMID: 28004314 DOI: 10.1007/s40263-016-0402-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The misuse of γ-hydroxybutyrate (GHB) for recreational purposes has resulted in an increase in GHB-related problems such as intoxications, dependence and withdrawal in several countries in Europe, Australia and the US over the last decade. However, prevalence rates of misuse of GHB and its precursor, γ-butyrolactone (GBL), are still relatively low. In this qualitative review paper, after a short introduction on the pharmacology of GHB/GBL, followed by a summary of the epidemiology of GHB abuse, an overview of GHB dependence syndrome and GHB/GBL withdrawal syndrome is provided. Finally, the existing literature on management of GHB detoxification, both planned and unplanned, as well as the available management of GHB withdrawal syndrome, is summarized. Although no systematic studies on detoxification and management of withdrawal have been performed to date, general recommendations are given on pharmacological treatment and preferred treatment setting.
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Affiliation(s)
- Rama M Kamal
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Toernooiveld 5, 6525 ED, Nijmegen, The Netherlands.
- Novadic-Kentron Addiction Care Network, Hogedwarsstraat 3, PO Box 243, 5260 AE, Vught, The Netherlands.
| | | | - Wim Wannet
- Scientific Research Committee IrisZorg, Kronenburgsingel 545, 6831 GM, Arnhem, The Netherlands
| | - Harmen Beurmanjer
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Toernooiveld 5, 6525 ED, Nijmegen, The Netherlands
- Novadic-Kentron Addiction Care Network, Hogedwarsstraat 3, PO Box 243, 5260 AE, Vught, The Netherlands
| | - Boukje A G Dijkstra
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Toernooiveld 5, 6525 ED, Nijmegen, The Netherlands
| | - Arnt Schellekens
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Toernooiveld 5, 6525 ED, Nijmegen, The Netherlands
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14
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Klein AB, Bay T, Villumsen IS, Falk-Petersen CB, Marek A, Frølund B, Clausen RP, Hansen HD, Knudsen GM, Wellendorph P. Autoradiographic imaging and quantification of the high-affinity GHB binding sites in rodent brain using 3H-HOCPCA. Neurochem Int 2016; 100:138-145. [PMID: 27615059 DOI: 10.1016/j.neuint.2016.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 09/02/2016] [Accepted: 09/06/2016] [Indexed: 11/25/2022]
Abstract
GHB (γ-hydroxybutyric acid) is a compound endogenous to mammalian brain with high structural resemblance to GABA. GHB possesses nanomolar-micromolar affinity for a unique population of binding sites, but the exact nature of these remains elusive. In this study we utilized the highly selective GHB analogue, 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) as a tritiated version (3H-HOCPCA) to radioactively label the specific GHB high-affinity binding site and gain further insight into the density, distribution and developmental profile of this protein. We show that, in low nanomolar concentrations, 3H-HOCPCA displays excellent signal-to-noise ratios using rodent brain autoradiography, which makes it a valuable ligand for anatomical quantification of native GHB binding site levels. Our data confirmed that 3H-HOCPCA labels only the high-affinity specific GHB binding site, found in high density in cortical and hippocampal regions. The experiments revealed markedly stronger binding at pH 6.0 (Kd 73.8 nM) compared to pH 7.4 (Kd 2312 nM), as previously reported for other GHB radioligands but similar Bmax values. Using 3H-HOCPCA we analyzed the GHB binding protein profile during mouse brain development. Due to the high sensitivity of this radioligand, we were able to detect low levels of specific binding already at E15 in mouse brain, which increased progressively until adulthood. Collectively, we show that 3H-HOCPCA is a highly sensitive radioligand, offering advantages over the commonly used radioligand 3H-NCS-382, and thus a very suitable in vitro tool for qualitative and quantitative autoradiography of the GHB high-affinity site.
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Affiliation(s)
- A B Klein
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - T Bay
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - I S Villumsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - C B Falk-Petersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - A Marek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 6 Prague, Czech Republic
| | - B Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - R P Clausen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - H D Hansen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - G M Knudsen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - P Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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15
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Marek A, Pedersen MH, Vogensen SB, Clausen RP, Frølund B, Elbert T. The labeling of unsaturated γ-hydroxybutyric acid by heavy isotopes of hydrogen: iridium complex-mediated H/D exchange by C─H bond activation vs reduction by boro-deuterides/tritides. J Labelled Comp Radiopharm 2016; 59:476-483. [DOI: 10.1002/jlcr.3432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/26/2016] [Accepted: 07/22/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Aleš Marek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, v.v.i.; Flemingovo nám. 2 Prague 6 16610 Czech Republic
- Center for Nuclear Technologies, DTU Nutech/Hevesy Laboratory; Technical University of Denmark; Frederiksborgvej 399, Building 202 Roskilde 4000 Denmark
| | - Martin H.F. Pedersen
- Center for Nuclear Technologies, DTU Nutech/Hevesy Laboratory; Technical University of Denmark; Frederiksborgvej 399, Building 202 Roskilde 4000 Denmark
| | - Stine B. Vogensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Denmark
| | - Rasmus P. Clausen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; 2100 Copenhagen Denmark
| | - Tomáš Elbert
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, v.v.i.; Flemingovo nám. 2 Prague 6 16610 Czech Republic
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16
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Thiesen L, Kehler J, Clausen RP, Frølund B, Bundgaard C, Wellendorph P. In Vitro and In Vivo Evidence for Active Brain Uptake of the GHB Analog HOCPCA by the Monocarboxylate Transporter Subtype 1. J Pharmacol Exp Ther 2015; 354:166-74. [PMID: 25986445 DOI: 10.1124/jpet.115.224543] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/11/2015] [Indexed: 01/03/2023] Open
Abstract
γ-Hydroxybutyric acid (GHB) is a recreational drug, a clinically prescribed drug in narcolepsy and alcohol dependence, and an endogenous substance that binds to both high- and low-affinity sites in the brain. For studying the molecular mechanisms and the biologic role of the GHB high-affinity binding sites, ligands with high and specific affinity are essential. The conformationally restricted GHB analog HOCPCA (3-hydroxycyclopent-1-enecarboxylic acid) is one such compound. The objective of this study was to investigate the transport of HOCPCA across the blood-brain barrier in vitro and in vivo and to investigate the hypothesis that HOCPCA, like GHB, is a substrate for the monocarboxylate transporters (MCTs). For in vitro uptake studies, MCT1, -2, and -4 were recombinantly expressed in Xenopus laevis oocytes, and the previously reported radioligand [(3)H]HOCPCA was used as substrate. HOCPCA inhibited the uptake of the endogenous MCT substrate l-[(14)C]lactate, and [(3)H]HOCPCA was shown to act as substrate for MCT1 and 2 (Km values in the low- to mid-millimolar range). Introducing single-point amino acid mutations into positions essential for MCT function supported that HOCPCA binds to the endogenous substrate pocket of MCTs. MCT1-mediated brain entry of HOCPCA (10 mg/kg s.c.) was further confirmed in vivo in mice by coadministration of increasing doses of the MCT inhibitor AR-C141990 [(R)-5-(3-hydroxypyrrolidine-1-carbonyl)-1-isobutyl-3-methyl-6-(quinolin-4-ylmethyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione], which inhibited brain penetration of HOCPCA in a dose-dependent manner (ID50 = 4.6 mg/kg). Overall, our study provides evidence that MCT1 is an important brain entry site for HOCPCA and qualifies for future in vivo studies with HOCPCA.
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Affiliation(s)
- Louise Thiesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
| | - Jan Kehler
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
| | - Rasmus P Clausen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
| | - Christoffer Bundgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.T., R.P.C., B.F., P.W.); and Discovery Chemistry and DMPK, H. Lundbeck A/S, Ottiliavej, Valby, Denmark (J.K., C.B.)
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17
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18
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Management of Gamma-Butyrolactone Dependence with Assisted Self-Administration of GBL. Case Rep Neurol Med 2014; 2014:485178. [PMID: 25054071 PMCID: PMC4099022 DOI: 10.1155/2014/485178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 06/17/2014] [Indexed: 11/17/2022] Open
Abstract
Gamma-hydroxybutyric acid (GHB) and its liquid precursor gamma-butyrolactone (GBL) have become increasingly popular beyond the clubbing culture resulting in daily consumption and dependence in the broader population. This case report illustrates the challenges of managing GHB-withdrawal and a possibly superior future approach of its management by titration and tapering of the addictive agent.
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19
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Positive allosteric modulation of the GHB high-affinity binding site by the GABAA receptor modulator monastrol and the flavonoid catechin. Eur J Pharmacol 2014; 740:570-7. [PMID: 24973695 DOI: 10.1016/j.ejphar.2014.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 06/16/2014] [Accepted: 06/18/2014] [Indexed: 11/21/2022]
Abstract
γ-Hydroxybutyric acid (GHB) is a metabolite of γ-aminobutyric acid (GABA) and a proposed neurotransmitter in the mammalian brain. We recently identified α4βδ GABAA receptors as possible high-affinity GHB targets. GABAA receptors are highly sensitive to allosteric modulation. Thus to investigate whether GHB high-affinity binding sites are also sensitive to allosteric modulation, we screened both known GABAA receptor ligands and a library of natural compounds in the rat cortical membrane GHB specific high-affinity [3H]NCS-382 binding assay. Two hits were identified: Monastrol, a positive allosteric modulator of GABA function at δ-containing GABAA receptors, and the naturally occurring flavonoid catechin. These compounds increased [3H]NCS-382 binding to 185-272% in high micromolar concentrations. Monastrol and (+)-catechin significantly reduced [3H]NCS-382 dissociation rates and induced conformational changes in the binding site, demonstrating a positive allosteric modulation of radioligand binding. Surprisingly, binding of [3H]GHB and the GHB high-affinity site-specific radioligands [125I]BnOPh-GHB and [3H]HOCPCA was either decreased or only weakly increased, indicating that the observed modulation was critically probe-dependent. Both monastrol and (+)-catechin were agonists at recombinant α4β3δ receptors expressed in Xenopus laevis oocytes. When monastrol and GHB were co-applied no changes were seen compared to the individual responses. In summary, we have identified the compounds monastrol and catechin as the first allosteric modulators of GHB high-affinity binding sites. Despite their relatively weak affinity, these compounds may aid in further characterization of the GHB high-affinity sites that are likely to represent certain GABAA receptors.
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