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Wong SQ, Pontifex MG, Phelan MM, Pidathala C, Kraemer BC, Barclay JW, Berry NG, O'Neill PM, Burgoyne RD, Morgan A. α-Methyl-α-phenylsuccinimide ameliorates neurodegeneration in a C. elegans model of TDP-43 proteinopathy. Neurobiol Dis 2018; 118:40-54. [PMID: 29940336 PMCID: PMC6097874 DOI: 10.1016/j.nbd.2018.06.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/06/2018] [Accepted: 06/15/2018] [Indexed: 12/12/2022] Open
Abstract
The antiepileptic drug ethosuximide has recently been shown to be neuroprotective in various Caenorhabditis elegans and rodent neurodegeneration models. It is therefore a promising repurposing candidate for the treatment of multiple neurodegenerative diseases. However, high concentrations of the drug are required for its protective effects in animal models, which may impact on its translational potential and impede the identification of its molecular mechanism of action. Therefore, we set out to develop more potent neuroprotective lead compounds based on ethosuximide as a starting scaffold. Chemoinformatic approaches were used to identify compounds with structural similarity to ethosuximide and to prioritise these based on good predicated blood-brain barrier permeability and C. elegans bioaccumulation properties. Selected compounds were initially screened for anti-convulsant activity in a C. elegans pentylenetetrazol-induced seizure assay, as a rapid primary readout of bioactivity; and then assessed for neuroprotective properties in a C. elegans TDP-43 proteinopathy model based on pan-neuronal expression of human A315T mutant TDP-43. The most potent compound screened, α-methyl-α-phenylsuccinimide (MPS), ameliorated the locomotion defects and extended the shortened lifespan of TDP-43 mutant worms. MPS also directly protected against neurodegeneration by reducing the number of neuronal breaks and cell body losses in GFP-labelled GABAergic motor neurons. Importantly, optimal neuroprotection was exhibited by external application of 50 μM MPS, compared to 8 mM for ethosuximide. This greater potency of MPS was not due to bioaccumulation to higher internal levels within the worm, based on 1H-nuclear magnetic resonance analysis. Like ethosuximide, the activity of MPS was abolished by mutation of the evolutionarily conserved FOXO transcription factor, daf-16, suggesting that both compounds act via the same neuroprotective pathway(s). In conclusion, we have revealed a novel neuroprotective activity of MPS that is >100-fold more potent than ethosuximide. This increased potency will facilitate future biochemical studies to identify the direct molecular target(s) of both compounds, as we have shown here that they share a common downstream DAF-16-dependent mechanism of action. Furthermore, MPS is the active metabolite of another approved antiepileptic drug, methsuximide. Therefore, methsuximide may have repurposing potential for treatment of TDP-43 proteinopathies and possibly other human neurodegenerative diseases.
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Affiliation(s)
- Shi Quan Wong
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Matthew G Pontifex
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Marie M Phelan
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
| | | | - Brian C Kraemer
- Geriatrics Research Education and Clinical Center, Seattle Veterans Affairs Puget Sound Health Care System, University of Washington Department of Medicine, Seattle, WA 98108, USA.
| | - Jeff W Barclay
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Neil G Berry
- Department of Chemistry, University of Liverpool, Liverpool, UK.
| | - Paul M O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, UK.
| | - Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Alan Morgan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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Krivoshein AV. Anticonvulsants Based on the α-Substituted Amide Group Pharmacophore Bind to and Inhibit Function of Neuronal Nicotinic Acetylcholine Receptors. ACS Chem Neurosci 2016; 7:316-26. [PMID: 26741746 DOI: 10.1021/acschemneuro.5b00259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although the antiepileptic properties of α-substituted lactams, acetamides, and cyclic imides have been known for over 60 years, the mechanism by which they act remains unclear. I report here that these compounds bind to the nicotinic acetylcholine receptor (nAChR) and inhibit its function. Using transient kinetic measurements with functionally active, nondesensitized receptors, I have discovered that (i) α-substituted lactams and cyclic imides are noncompetitive inhibitors of heteromeric subtypes (such as α4β2 and α3β4) of neuronal nAChRs and (ii) the binding affinity of these compounds toward the nAChR correlates with their potency in preventing maximal electroshock (MES)-induced convulsions in mice. Based on the hypothesis that α-substituted amide group is the essential pharmacophore of these drugs, I found and tested a simple compound, 2-phenylbutyramide. This compound indeed inhibits nAChR and shows good anticonvulsant activity in mice. Molecular docking simulations suggest that α-substituted lactams, acetamides, and cyclic imides bind to the same sites on the extracellular domain of the receptor. These new findings indicate that inhibition of brain nAChRs may play an important role in the action of these antiepileptic drugs, a role that has not been previously recognized.
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Affiliation(s)
- Arcadius V. Krivoshein
- Department of Basic and Social
Sciences, Albany College of Pharmacy and Health Sciences, 106
New Scotland Avenue, Albany, New York 12208, United States
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Ordonez C, Pavlovetc IM, Khrustalev VN. Crystal structure of 1,3-dimethyl-3-phenyl-pyrrolidine-2,5-dione: a clinically used anti-convulsant. Acta Crystallogr Sect E Struct Rep Online 2014; 70:o942-3. [PMID: 25309268 PMCID: PMC4186160 DOI: 10.1107/s1600536814016717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 07/18/2014] [Indexed: 11/25/2022]
Abstract
In the title compound, C12H13NO2, the five-membered ring has an envelope conformation; the disubstituted C atom lies out of the mean plane through the four other ring atoms (r.m.s. deviation = 0.0038 Å) by 0.1877 (18) Å. The plane of the phenyl substituent is practically perpendicular to that of the planar part of the five-membered ring, with a dihedral angle of 87.01 (5)°. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming inversion dimers. The dimers are linked by further C-H⋯O hydrogen bonds, as well as carbon-yl-carbonyl attractive inter-actions [O⋯C = 3.2879 (19) Å], forming a three-dimensional framework structure.
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Affiliation(s)
- Carlos Ordonez
- Department of Chemistry & Biology, New Mexico Highlands University, 803 University Avenue, Las Vegas, NM 87701, USA
| | - Ilia M. Pavlovetc
- Department of Engineering Photonics, St Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University), 49 Kronverkskiy Avenue, St Petersburg 197101, Russian Federation
| | - Victor N. Khrustalev
- X-Ray Structural Centre, A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, B-334, Moscow 119991, Russian Federation
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