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Zahn N, Roni MSR, Yocum GT, Meyer MJ, Webb DA, Mian MY, Cook JM, Stafford DC, Emala CW, Arnold LA. Development of Inhaled GABA A Receptor Modulators to Improve Airway Function in Bronchoconstrictive Disorders. ACS Pharmacol Transl Sci 2022; 5:80-88. [PMID: 35187417 PMCID: PMC8844962 DOI: 10.1021/acsptsci.1c00238] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Indexed: 02/03/2023]
Abstract
We report the modification of MIDD0301, an imidazodiazepine GABAA receptor (GABAAR) ligand, using two alkyl substituents. We developed PI310 with a 6-(4-phenylbutoxy)hexyl chain as used in the long-acting β2-agonist salmeterol and PI320 with a poly(ethylene glycol) chain as used to improve the brain:plasma ratio of naloxegol, a naloxone analogue. Both imidazodiazepines showed affinity toward the GABAAR binding site of clonazepam, with IC50 values of 576 and 242 nM, respectively. Molecular docking analysis, using the available α1β3γ2 GABAAR structural data, suggests binding of the diazepine core between the α1+/γ2- interface, whereas alkyl substituents are located outside the binding site and thus interact with the protein surface and solvent molecules. The physicochemical properties of these compounds are very different. The solubility of PI310 is low in water. PEGylation of PI320 significantly improves aqueous solubility and cell permeability. Neither compound is toxic in HEK293 cells following exposure at >300 μM for 18 h. Ex vivo studies using guinea pig tracheal rings showed that PI310 was unable to relax the constricted airway smooth muscle. In contrast, PI320 induced muscle relaxation at organ bath concentrations as low as 5 μM, with rapid onset (15 min) at 25 μM. PI320 also reduced airway hyper-responsiveness in vivo in a mouse model of steroid-resistant lung inflammation induced by intratracheal challenge with INFγ and lipopolysaccharide (LPS). At nebulized doses of 7.2 mg/kg, PI320 and albuterol were equally effective in reducing airway hyper-responsiveness. Ten minutes after nebulization, the lung concentration of PI320 was 50-fold that of PI310, indicating superior availability of PI320 when nebulized as an aqueous solution. Overall, PI320 is a promising inhaled drug candidate to quickly relax airway smooth muscle in bronchoconstrictive disorders, such as asthma. Future studies will evaluate the pharmacokinetic/pharmacodynamic properties of PI320 when administered orally.
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Affiliation(s)
- Nicolas
M. Zahn
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - M. S. Rashid Roni
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Gene T. Yocum
- Department
of Anesthesiology, Columbia University, New York, New York 10032, United States
| | - Michelle J. Meyer
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Daniel A. Webb
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Md Yeunus Mian
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - James M. Cook
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | | | - Charles W. Emala
- Department
of Anesthesiology, Columbia University, New York, New York 10032, United States
| | - Leggy A. Arnold
- Department
of Chemistry and Biochemistry and the Milwaukee Institute for Drug
Discovery, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States,Pantherics
Incorporated, La Jolla, California 92037, United States,
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Majeed K, Wang L, Liu B, Guo Z, Zhou F, Zhang Q. Metal-Free Tandem Approach for Triazole-Fused Diazepinone Scaffolds via [3 + 2]Cycloaddition/C–N Coupling Reaction. J Org Chem 2020; 86:207-222. [DOI: 10.1021/acs.joc.0c02022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Kashif Majeed
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
| | - Lingna Wang
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
| | - Bangjie Liu
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
| | - Zijian Guo
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
| | - Fengtao Zhou
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
| | - Qiuyu Zhang
- Xi’an Key Laboratory of Functional Organic Porous Materials, Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, P. R. China
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3
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Wu D, Zhang X, Li Y, Ying S, Zhu L, Li Z, Yang G, Van der Eycken EV. Divergent Access to Imidazopyrazinones and Imidazodiazepinones by Regioswitchable Post-Ugi Heteroannulation. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901511] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Danjun Wu
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Xueling Zhang
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Yi Li
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Sanjun Ying
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Lixi Zhu
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Zhenghua Li
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC); Department of Chemistry; KU Leuven; Celestijnenlaan 200F 3001 Leuven Heverlee Belgium
| | - Gensheng Yang
- College of Pharmaceutical Science; Zhejiang University of Technology; 18 Chaowang Road 310014 Hangzhou China
| | - Erik V. Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC); Department of Chemistry; KU Leuven; Celestijnenlaan 200F 3001 Leuven Heverlee Belgium
- Peoples Friendship University of Russia (RUDN University); 117198 Moscow Russia
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4
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Kaur N. Synthesis of six- and seven-membered and larger heterocylces using Au and Ag catalysts. INORG NANO-MET CHEM 2019. [DOI: 10.1080/24701556.2019.1567544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Navjeet Kaur
- Department of Chemistry, Banasthali Vidyapith, Banasthali, Rajasthan, India
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5
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Sieghart W, Savić MM. International Union of Basic and Clinical Pharmacology. CVI: GABAA Receptor Subtype- and Function-selective Ligands: Key Issues in Translation to Humans. Pharmacol Rev 2018; 70:836-878. [DOI: 10.1124/pr.117.014449] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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6
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Chandler CM, Overton JS, Rüedi-Bettschen D, Platt DM. GABA A Receptor Subtype Mechanisms and the Abuse-Related Effects of Ethanol: Genetic and Pharmacological Evidence. Handb Exp Pharmacol 2018; 248:3-27. [PMID: 29204713 DOI: 10.1007/164_2017_80] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ethanol's reinforcing and subjective effects, as well as its ability to induce relapse, are powerful factors contributing to its widespread use and abuse. A significant mediator of these behavioral effects is the GABAA receptor system. GABAA receptors are the target for γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the CNS. Structurally, they are pentameric, transmembrane chloride ion channels comprised of subunits from at least eight different families of distinct proteins. The contribution of different GABAA subunits to ethanol's diverse abuse-related effects is not clear and remains an area of research focus. This chapter details the clinical and preclinical findings supporting roles for different α, β, γ, and δ subunit-containing GABAA receptors in ethanol's reinforcing, subjective/discriminative stimulus, and relapse-inducing effects. The reinforcing properties of ethanol have been studied the most systematically, and convergent preclinical evidence suggests a key role for the α5 subunit in those effects. Regarding ethanol's subjective/discriminative stimulus effects, clinical and genetic findings support a primary role for the α2 subunit, whereas preclinical evidence implicates the α5 subunit. At present, too few studies investigating ethanol relapse exist to make any solid conclusions regarding the role of specific GABAA subunits in this abuse-related effect.
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Affiliation(s)
- Cassie M Chandler
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA
| | - John S Overton
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Daniela Rüedi-Bettschen
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Donna M Platt
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA.
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
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Fischer BD, Platt DM, Rallapalli SK, Namjoshi OA, Cook JM, Rowlett JK. Antagonism of triazolam self-administration in rhesus monkeys responding under a progressive-ratio schedule: In vivo apparent pA2 analysis. Drug Alcohol Depend 2016; 158:22-9. [PMID: 26596587 PMCID: PMC4698084 DOI: 10.1016/j.drugalcdep.2015.10.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/19/2015] [Accepted: 10/19/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Conventional benzodiazepines bind non-selectively to GABAA receptors containing α1, α2, α3, and α5 subunits (α1GABAA, α2GABAA, α3GABAA, and α5GABAA receptors, respectively), and the role of these different GABAA receptor subtypes in the reinforcing effects of benzodiazepines has not been characterized fully. We used a pharmacological antagonist approach with available subtype-selective ligands to evaluate the role of GABAA receptor subtypes in the reinforcing effects of the non-selective conventional benzodiazepine, triazolam. METHODS Rhesus monkeys (n=4) were trained under a progressive-ratio schedule of intravenous midazolam delivery and dose-response functions were determined for triazolam, in the absence and presence of flumazenil (non-selective antagonist), βCCT and 3-PBC (α1GABAA-preferring antagonists), and XLi-093 (α5GABAA-selective antagonist). RESULTS Flumazenil, βCCT and 3-PBC shifted the dose-response functions for triazolam to the right in a surmountable fashion, whereas XLi-093 was ineffective. Schild analyses revealed rank orders of potencies of flumazenil=βCCT>3-PBC. Comparison of potencies between self-administration and previous binding studies with human cloned GABAA receptor subtypes suggested that the potencies for βCCT and 3-PBC were most consistent with binding at α2GABAA and α3GABAA receptors, but not α1GABAA or α5GABAA receptor subtypes. CONCLUSIONS Our findings were not entirely consistent with blockade of α1GABAA receptors and are consistent with the possibility of α2GABAA and/or α3GABAA subtype involvement in antagonism of the reinforcing effects of triazolam. The α5GABAA receptor subtype likely does not play a substantial role in self-administration under these conditions.
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Affiliation(s)
- Bradford D. Fischer
- Harvard Medical School, New England Primate Research Center, One Pine Hill Drive, PO Box 9102, Southborough, MA 01772-9102, USA
| | - Donna M. Platt
- Harvard Medical School, New England Primate Research Center, One Pine Hill Drive, PO Box 9102, Southborough, MA 01772-9102, USA
| | - Sundari K. Rallapalli
- University of Wisconsin–Milwaukee, Department of Chemistry and Biochemistry, Milwaukee, WI 53201, USA
| | - Ojas A. Namjoshi
- University of Wisconsin–Milwaukee, Department of Chemistry and Biochemistry, Milwaukee, WI 53201, USA
| | - James M. Cook
- University of Wisconsin–Milwaukee, Department of Chemistry and Biochemistry, Milwaukee, WI 53201, USA
| | - James K. Rowlett
- Harvard Medical School, New England Primate Research Center, One Pine Hill Drive, PO Box 9102, Southborough, MA 01772-9102, USA,Corresponding author. Current address: Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, USA. Tel.: +1 601 984 4488. (J.K. Rowlett)
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8
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Li SQ, Gao H, Lei J, Wang J, Xu J, Chen ZZ, Xu ZG. Efficient and facile synthesis of fused benzimidazole-diazepinones and dibenzimidazole-diazepines via a UDC strategy and the hydroamination of an alkyne. RSC Adv 2016. [DOI: 10.1039/c5ra24813b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microwave assisted synthesis of fused benzimidazole-diazepinones and dibenzimidazole-diazepines using a one-pot procedure.
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Affiliation(s)
- Shi-Qiang Li
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
| | - Hongyan Gao
- Department of Medical Administration
- General Hospital of Beijing Military Command
- China 100700
| | - Jie Lei
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
| | - Jun Wang
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
| | - Jia Xu
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
| | - Zhong-Zhu Chen
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
| | - Zhi-Gang Xu
- International Academy of Targeted Therapeutics
- and Innovation
- Chongqing University of Arts and Sciences
- Chongqing
- China 402160
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9
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A Review of the Updated Pharmacophore for the Alpha 5 GABA(A) Benzodiazepine Receptor Model. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2015; 2015:430248. [PMID: 26682068 PMCID: PMC4657098 DOI: 10.1155/2015/430248] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/16/2015] [Accepted: 07/02/2015] [Indexed: 12/22/2022]
Abstract
An updated model of the GABA(A) benzodiazepine receptor pharmacophore of the α5-BzR/GABA(A) subtype has been constructed prompted by the synthesis of subtype selective ligands in light of the recent developments in both ligand synthesis, behavioral studies, and molecular modeling studies of the binding site itself. A number of BzR/GABA(A) α5 subtype selective compounds were synthesized, notably α5-subtype selective inverse agonist PWZ-029 (1) which is active in enhancing cognition in both rodents and primates. In addition, a chiral positive allosteric modulator (PAM), SH-053-2′F-R-CH3 (2), has been shown to reverse the deleterious effects in the MAM-model of schizophrenia as well as alleviate constriction in airway smooth muscle. Presented here is an updated model of the pharmacophore for α5β2γ2 Bz/GABA(A) receptors, including a rendering of PWZ-029 docked within the α5-binding pocket showing specific interactions of the molecule with the receptor. Differences in the included volume as compared to α1β2γ2, α2β2γ2, and α3β2γ2 will be illustrated for clarity. These new models enhance the ability to understand structural characteristics of ligands which act as agonists, antagonists, or inverse agonists at the Bz BS of GABA(A) receptors.
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10
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Varagic Z, Ramerstorfer J, Huang S, Rallapalli S, Sarto-Jackson I, Cook J, Sieghart W, Ernst M. Subtype selectivity of α+β- site ligands of GABAA receptors: identification of the first highly specific positive modulators at α6β2/3γ2 receptors. Br J Pharmacol 2014; 169:384-99. [PMID: 23472935 DOI: 10.1111/bph.12153] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 12/21/2012] [Accepted: 01/31/2013] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors are the major inhibitory neurotransmitter receptors in the mammalian brain and the target of many clinically important drugs interacting with different binding sites. Recently, we demonstrated that CGS 9895 (2-(4-methoxyphenyl)-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) elicits a strong and subtype-dependent enhancement of GABA-induced currents via a novel drug-binding site at extracellular αx+βy- (x = 1-6, y = 1-3) interfaces. Here, we investigated 16 structural analogues of CGS 9895 for their ability to modulate GABA-induced currents of various GABAA receptor subtypes. EXPERIMENTAL APPROACH Recombinant GABAA receptor subtypes were expressed in Xenopus laevis oocytes and investigated by the two-electrode voltage clamp method. KEY RESULTS Most of the compounds investigated were able to modulate GABA-induced currents of αβ and αβγ receptors to a comparable extent, suggesting that the effect of these drugs is not dependent on the benzodiazepine site of GABAA receptors. Steric hindrance experiments demonstrated that these compounds exert their action predominantly via the αx+βy- (x = 1-6, y = 1-3) interfaces. Whereas some compounds are unselectively modulating a broad range of receptor subtypes, other compounds feature remarkable functional selectivity for the α6β3γ2 receptor, or behave as null modulators at some receptor subtypes investigated. CONCLUSION AND IMPLICATIONS Pyrazoloquinolinones and pyrazolopyridinones represent the first prototypes of drugs exerting benzodiazepine-like modulatory effects via the α+β- interface of GABAA receptors. The discovery of modulators with functional subtype selectivity at this class of binding sites provides a highly useful tool for the investigation of α6β2/3γ2 receptor function, and may lead to novel therapeutic principles.
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Affiliation(s)
- Zdravko Varagic
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Vienna, Austria
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11
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Varagic Z, Wimmer L, Schnürch M, Mihovilovic MD, Huang S, Rallapalli S, Cook JM, Mirheydari P, Ecker GF, Sieghart W, Ernst M. Identification of novel positive allosteric modulators and null modulators at the GABAA receptor α+β- interface. Br J Pharmacol 2014; 169:371-83. [PMID: 23472852 DOI: 10.1111/bph.12151] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 12/21/2012] [Accepted: 01/31/2013] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors are the major inhibitory neurotransmitter receptors in the mammalian brain and the target of many clinically important drugs interacting with different binding sites. Recently, we demonstrated that CGS 9895 (2-(4-methoxyphenyl)-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) acts as a null modulator (antagonist) at the high affinity benzodiazepine binding site, but in addition elicits a strong enhancement of GABA-induced currents via a novel drug binding site at the extracellular α+β- interface. Here, we investigated 32 structural analogues of CGS 9895 for their ability to mediate their effects via the α1+β3- interface of GABAA receptors. EXPERIMENTAL APPROACH GABAA receptors were expressed in Xenopus laevis oocytes and investigated by the two-electrode voltage clamp method. KEY RESULTS We not only identified compounds with higher efficacy/potency than CGS 9895 for stimulating GABA-induced currents via the α1+β3-binding site, but also discovered compounds acting as null modulators at this site. Most of the compounds also acted as null modulators via the benzodiazepine binding site of GABAA receptors. But some of the positive allosteric modulators or null modulators exclusively exerted their action via the α+β- binding site. CONCLUSION AND IMPLICATIONS Pyrazoloquinolinones and pyrazolopyridinones represent the first prototype of drug candidates mediating benzodiazepine like modulatory effects via the α+β-interface of GABAA receptors. The discovery of null modulators acting as inhibitors of the plus modulators provides a highly useful tool for the discovery of additional classes of compounds that can modulate GABAA receptors via this site, which may lead to novel therapeutic principles.
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Affiliation(s)
- Zdravko Varagic
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, Vienna, Austria
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12
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Sengupta S, Weeraratne SD, Sun H, Phallen J, Rallapalli SK, Teider N, Kosaras B, Amani V, Pierre-Francois J, Tang Y, Nguyen B, Yu F, Schubert S, Balansay B, Mathios D, Lechpammer M, Archer TC, Tran P, Reimer RJ, Cook JM, Lim M, Jensen FE, Pomeroy SL, Cho YJ. α5-GABAA receptors negatively regulate MYC-amplified medulloblastoma growth. Acta Neuropathol 2014; 127:593-603. [PMID: 24196163 DOI: 10.1007/s00401-013-1205-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 10/28/2013] [Indexed: 11/25/2022]
Abstract
Neural tumors often express neurotransmitter receptors as markers of their developmental lineage. Although these receptors have been well characterized in electrophysiological, developmental and pharmacological settings, their importance in the maintenance and progression of brain tumors and, importantly, the effect of their targeting in brain cancers remains obscure. Here, we demonstrate high levels of GABRA5, which encodes the α5-subunit of the GABAA receptor complex, in aggressive MYC-driven, "Group 3" medulloblastomas. We hypothesized that modulation of α5-GABAA receptors alters medulloblastoma cell survival and monitored biological and electrophysiological responses of GABRA5-expressing medulloblastoma cells upon pharmacological targeting of the GABAA receptor. While antagonists, inverse agonists and non-specific positive allosteric modulators had limited effects on medulloblastoma cells, a highly specific and potent α5-GABAA receptor agonist, QHii066, resulted in marked membrane depolarization and a significant decrease in cell survival. This effect was GABRA5 dependent and mediated through the induction of apoptosis as well as accumulation of cells in S and G2 phases of the cell cycle. Chemical genomic profiling of QHii066-treated medulloblastoma cells confirmed inhibition of MYC-related transcriptional activity and revealed an enrichment of HOXA5 target gene expression. siRNA-mediated knockdown of HOXA5 markedly blunted the response of medulloblastoma cells to QHii066. Furthermore, QHii066 sensitized GABRA5 positive medulloblastoma cells to radiation and chemotherapy consistent with the role of HOXA5 in directly regulating p53 expression and inducing apoptosis. Thus, our results provide novel insights into the synthetic lethal nature of α5-GABAA receptor activation in MYC-driven/Group 3 medulloblastomas and propose its targeting as a novel strategy for the management of this highly aggressive tumor.
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Affiliation(s)
- Soma Sengupta
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
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Microwave-assisted synthesis of 4H-benzo[f]imidazo[1,4]diazepin-6-ones via a post-Ugi copper-catalyzed intramolecular Ullmann coupling. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.02.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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14
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Hussain MK, Ansari MI, Kant R, Hajela K. Tandem C-2 Functionalization–Intramolecular Azide–Alkyne 1,3-Dipolar Cycloaddition Reaction: A Convenient Route to Highly Diversified 9H-Benzo[b]pyrrolo[1,2-g][1,2,3]triazolo[1,5-d][1,4]diazepines. Org Lett 2013; 16:560-3. [DOI: 10.1021/ol403420z] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Mohd. Kamil Hussain
- Medicinal and Process Chemistry
Division and §Molecular and Structural Biology
Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension,
Sitapur Road Lucknow 226031, India
| | - Mohd. Imran Ansari
- Medicinal and Process Chemistry
Division and §Molecular and Structural Biology
Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension,
Sitapur Road Lucknow 226031, India
| | - Ruchir Kant
- Medicinal and Process Chemistry
Division and §Molecular and Structural Biology
Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension,
Sitapur Road Lucknow 226031, India
| | - Kanchan Hajela
- Medicinal and Process Chemistry
Division and §Molecular and Structural Biology
Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension,
Sitapur Road Lucknow 226031, India
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Kumar A, Li Z, Sharma SK, Parmar VS, Eycken EVVD. An Expedient Route to Imidazo[1,4]diazepin-7-ones via A Post-Ugi Gold-Catalyzed Heteroannulation. Org Lett 2013; 15:1874-7. [DOI: 10.1021/ol400526a] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Amit Kumar
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Zhenghua Li
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Sunil K. Sharma
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Virinder S. Parmar
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
| | - Erik V. Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven), Celestijnenlaan 200F, B-3001 Leuven, Belgium, and Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India
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Rüedi-Bettschen D, Rowlett JK, Rallapalli S, Clayton T, Cook JM, Platt DM. Modulation of α5 subunit-containing GABAA receptors alters alcohol drinking by rhesus monkeys. Alcohol Clin Exp Res 2013; 37:624-34. [PMID: 23126673 PMCID: PMC3951841 DOI: 10.1111/acer.12018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 08/22/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Alcohol's ability to potentiate the activity of γ-aminobutyric acid (GABA) at GABAA receptors has been implicated as a key mechanism underlying the behavioral effects of alcohol. The complex molecular biology of these receptors raises the possibility that particular receptor subtypes may play unique roles in alcohol's abuse-related effects and that subtype-selective ligands with therapeutic specificity against alcohol might be developed. This study evaluated the capacity of α5GABAA receptor ligands to alter selectively the reinforcing effects of alcohol. METHODS Two groups of rhesus monkeys were trained to orally self-administer alcohol or sucrose under fixed-ratio schedules and limited daily access conditions. In addition, following daily self-administration sessions, the behavior of each monkey was scored for both species-typical and drug-induced behaviors. RESULTS Concentrations of 1 to 6% alcohol maintained self-administration above water levels, engendered pharmacologically relevant blood alcohol levels ranging from 90 to 160 mg/dl, and produced changes in behavior typical of alcohol intoxication. Concentrations of 0.3 to 3% sucrose also reliably maintained self-administration. The α5GABAA receptor agonist QH-ii-066 enhanced and the α5GABAA receptor inverse agonist L-655,708 inhibited alcohol, but not sucrose drinking. The changes in alcohol drinking could be reversed with the α5GABAA receptor antagonist XLi-093. However, L-655,708 increased yawning in both alcohol and sucrose drinkers, possibly indicative of an anxiogenic effect. CONCLUSIONS These findings suggest a prominent and specific role for α5GABAA receptor mechanisms in the reinforcing effects of alcohol. Moreover, these results suggest that α5GABAA receptors may represent a novel pharmacological target for the development of medications to reduce drinking. Of ligands modulating this receptor, α5GABAA receptor inverse agonists may hold the most promise as alcohol pharmacotherapies.
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17
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Makaron L, Moran CA, Namjoshi O, Rallapalli S, Cook JM, Rowlett JK. Cognition-impairing effects of benzodiazepine-type drugs: role of GABAA receptor subtypes in an executive function task in rhesus monkeys. Pharmacol Biochem Behav 2013; 104:62-8. [PMID: 23290931 DOI: 10.1016/j.pbb.2012.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/19/2012] [Accepted: 12/22/2012] [Indexed: 10/27/2022]
Abstract
The present studies evaluated the role of α1 and α5 subunit-containing GABAA receptors (α1GABAA and α5GABAA receptors, respectively) in the ability of benzodiazepine (BZ)-type drugs to alter performance in the cognitive domain of executive function. Five adult female rhesus monkeys (ages of 9-17years old) were trained on the object retrieval with detours (ORD) task of executive function. For the ORD task, the monkeys were required to retrieve food items from a clear box with one open end that was rotated to different positions along with varying placements of food. When the non-selective BZ triazolam and the α1GABAA-preferring agonists zolpidem and zaleplon were evaluated in the ORD task, deficits in performance occurred at doses that did not increase the latency of monkeys to initiate responding and/or increase the percentage of reaches that were incorrect (i.e., reaches in which food was not obtained). Cognition-impairing effects of triazolam and zolpidem in ORD were blocked by the α1GABAA-preferring antagonist, βCCT, whereas the α5GABAA-preferring antagonist XLi-093 blocked the effects of triazolam but not zolpidem. While these findings suggest a role for both α1GABAA and α5GABAA receptor mechanisms, α1GABAA receptor mechanisms appear to be sufficient for impairments in executive function induced by BZ-type drugs.
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Affiliation(s)
- Leah Makaron
- Division of Neuroscience, New England Primate Research Center, Harvard Medical School, Box 9102, 1 Pine Hill Drive, Southborough, MA 01772, USA.
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18
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The role of α1 and α5 subunit-containing GABAA receptors in motor impairment induced by benzodiazepines in rats. Behav Pharmacol 2012; 23:191-7. [PMID: 22327019 DOI: 10.1097/fbp.0b013e3283512c85] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Benzodiazepines negatively affect motor coordination and balance and produce myorelaxation. The aim of the present study was to examine the extent to which populations of γ-aminobutyric acid A (GABAA) receptors containing α1 and α5 subunits contribute to these motor-impairing effects in rats. We used the nonselective agonist diazepam and the α1-selective agonist zolpidem, as well as nonselective, α1-subunit and α5-subunit-selective antagonists flumazenil, βCCt, and XLi093, respectively. Ataxia and muscle relaxation were assessed by rotarod and grip strength tests performed 20 min after intraperitoneal treatment. Diazepam (2 mg/kg) induced significant ataxia and muscle relaxation, which were completely prevented by pretreatment with flumazenil (10 mg/kg) and βCCt (20 mg/kg). XLi093 antagonized the myorelaxant, but not the ataxic actions of diazepam. All three doses of zolpidem (1, 2, and 5 mg/kg) produced ataxia, but only the highest dose (5 mg/kg) significantly decreased the grip strength. These effects of zolpidem were reversed by βCCt at doses of 5 and 10 mg/kg, respectively. The present study demonstrates that α1 GABAA receptors mediate ataxia and indirectly contribute to myorelaxation in rats, whereas α5 GABAA receptors contribute significantly, although not dominantly, to muscle relaxation but not ataxia.
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19
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Tretter V, Kerschner B, Milenkovic I, Ramsden SL, Ramerstorfer J, Saiepour L, Maric HM, Moss SJ, Schindelin H, Harvey RJ, Sieghart W, Harvey K. Molecular basis of the γ-aminobutyric acid A receptor α3 subunit interaction with the clustering protein gephyrin. J Biol Chem 2011; 286:37702-11. [PMID: 21880742 DOI: 10.1074/jbc.m111.291336] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The multifunctional scaffolding protein gephyrin is a key player in the formation of the postsynaptic scaffold at inhibitory synapses, clustering both inhibitory glycine receptors (GlyRs) and selected GABA(A) receptor (GABA(A)R) subtypes. We report a direct interaction between the GABA(A)R α3 subunit and gephyrin, mapping reciprocal binding sites using mutagenesis, overlay, and yeast two-hybrid assays. This analysis reveals that critical determinants of this interaction are located in the motif FNIVGTTYPI in the GABA(A)R α3 M3-M4 domain and the motif SMDKAFITVL at the N terminus of the gephyrin E domain. GABA(A)R α3 gephyrin binding-site mutants were unable to co-localize with endogenous gephyrin in transfected hippocampal neurons, despite being able to traffic to the cell membrane and form functional benzodiazepine-responsive GABA(A)Rs in recombinant systems. Interestingly, motifs responsible for interactions with GABA(A)R α2, GABA(A)R α3, and collybistin on gephyrin overlap. Curiously, two key residues (Asp-327 and Phe-330) in the GABA(A)R α2 and α3 binding sites on gephyrin also contribute to GlyR β subunit-E domain interactions. However, isothermal titration calorimetry reveals a 27-fold difference in the interaction strength between GABA(A)R α3 and GlyR β subunits with gephyrin with dissociation constants of 5.3 μm and 0.2 μm, respectively. Taken together, these observations suggest that clustering of GABA(A)R α2, α3, and GlyRs by gephyrin is mediated by distinct mechanisms at mixed glycinergic/GABAergic synapses.
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Affiliation(s)
- Verena Tretter
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
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20
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Abstract
GABA(A) receptors mediate the action of many clinically important drugs interacting with different binding sites. For some potential binding sites, no interacting drugs have yet been identified. Here, we established a steric hindrance procedure for the identification of drugs acting at the extracellular α1+β3- interface, which is homologous to the benzodiazepine binding site at the α1+γ2- interface. On screening of >100 benzodiazepine site ligands, the anxiolytic pyrazoloquinoline 2-p-methoxyphenylpyrazolo[4,3-c]quinolin-3(5H)-one (CGS 9895) was able to enhance GABA-induced currents at α1β3 receptors from rat. CGS 9895 acts as an antagonist at the benzodiazepine binding site at nanomolar concentrations, but enhances GABA-induced currents via a different site present at α1β3γ2 and α1β3 receptors. By mutating pocket-forming amino acid residues at the α1+ and the β3- side to cysteines, we demonstrated that covalent labeling of these cysteines by the methanethiosulfonate ethylamine reagent MTSEA-biotin was able to inhibit the effect of CGS 9895. The inhibition was not caused by a general inactivation of GABA(A) receptors, because the GABA-enhancing effect of ROD 188 or the steroid α-tetrahydrodeoxycorticosterone was not influenced by MTSEA-biotin. Other experiments indicated that the CGS 9895 effect was dependent on the α and β subunit types forming the interface. CGS 9895 thus represents the first prototype of drugs mediating benzodiazepine-like modulatory effects via the α+β- interface of GABA(A) receptors. Since such binding sites are present at αβ, αβγ, and αβδ receptors, such drugs will have a much broader action than benzodiazepines and might become clinical important for the treatment of epilepsy.
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21
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Yin W, Majumder S, Clayton T, Petrou S, VanLinn ML, Namjoshi OA, Ma C, Cromer BA, Roth BL, Platt DM, Cook JM. Design, synthesis, and subtype selectivity of 3,6-disubstituted β-carbolines at Bz/GABA(A)ergic receptors. SAR and studies directed toward agents for treatment of alcohol abuse. Bioorg Med Chem 2010; 18:7548-64. [PMID: 20888240 PMCID: PMC2972656 DOI: 10.1016/j.bmc.2010.08.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 11/29/2022]
Abstract
A series of 3,6-disubstituted β-carbolines was synthesized and evaluated for their in vitro affinities at α(x)β(3)γ(2) GABA(A)/benzodiazepine receptor subtypes by radioligand binding assays in search of α(1) subtype selective ligands to treat alcohol abuse. Analogues of β-carboline-3-carboxylate-t-butyl ester (βCCt, 1) were synthesized via a CDI-mediated process and the related 6-substituted β-carboline-3-carboxylates 6 including WYS8 (7) were synthesized via a Sonogashira or Stille coupling processes from 6-iodo-βCCt (5). The bivalent ligands of βCCt (32 and 33) were also designed and prepared via a palladium-catalyzed homocoupling process to expand the structure-activity relationships (SAR) to larger ligands. Based on the pharmacophore/receptor model, a preliminary SAR study on 34 analogues illustrated that large substituents at position-6 of the β-carbolines were well tolerated. As expected, these groups are proposed to project into the extracellular domain (L(Di) region) of GABA(A)/Bz receptors (see 32 and 33). Moreover, substituents located at position-3 of the β-carboline nucleus exhibited a conserved stereo interaction in lipophilic pocket L(1), while N(2) presumably underwent a hydrogen bonding interaction with H(1). Three novel β-carboline ligands (βCCt, 3PBC and WYS8), which preferentially bound to α1 BzR subtypes permitted a comparison of the pharmacological efficacies with a range of classical BzR antagonists (flumazenil, ZK93426) from several different structural groups and indicated these β-carbolines were 'near GABA neutral antagonists'. Based on the SAR, the most potent (in vitro) α(1) selective ligand was the 6-substituted acetylenyl βCCt (WYS8, 7). Earlier both βCCt and 3PBC had been shown to reduce alcohol self-administration in alcohol preferring (P) and high alcohol drinking (HAD) rats but had little or no effect on sucrose self-administration.(1-3) Moreover, these two β-carbolines were orally active, and in addition, were anxiolytic in P rats but were only weakly anxiolytic in rodents. These data prompted the synthesis of the β-carbolines presented here.
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Affiliation(s)
- Wenyuan Yin
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413
| | - Samarpan Majumder
- Department of Pharmacology and Division of Medicinal Chemistry, University of North Carolina-Chapel Hill Medical School and School of Pharmacy and NIMH Psychoactive Drug Screening Program, 120 Mason Farm Road, 4072 Genetics Medicine Bldg, Chapel Hill, NC 27599-7365
| | - Terry Clayton
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413
| | - Steven Petrou
- Howard Florey Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael L. VanLinn
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413
| | | | - Chunrong Ma
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413
| | - Brett A. Cromer
- Howard Florey Institute, University of Melbourne, Parkville, VIC 3010, Australia
- Department of Pharmacology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Bryan L. Roth
- Department of Pharmacology and Division of Medicinal Chemistry, University of North Carolina-Chapel Hill Medical School and School of Pharmacy and NIMH Psychoactive Drug Screening Program, 120 Mason Farm Road, 4072 Genetics Medicine Bldg, Chapel Hill, NC 27599-7365
| | - Donna M. Platt
- Harvard Medical School, New England Primate Research Center, One Pine Hill Drive, Box 9102, Southborough, MA 01772-9102
| | - James M. Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201-0413
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22
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Ramerstorfer J, Furtmüller R, Vogel E, Huck S, Sieghart W. The point mutation gamma 2F77I changes the potency and efficacy of benzodiazepine site ligands in different GABAA receptor subtypes. Eur J Pharmacol 2010; 636:18-27. [PMID: 20303942 PMCID: PMC7615656 DOI: 10.1016/j.ejphar.2010.03.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 02/17/2010] [Accepted: 03/03/2010] [Indexed: 11/26/2022]
Abstract
Benzodiazepine site agonists or inverse agonists enhance or reduce gamma-aminobutyric acid(A) (GABA(A)) receptor-mediated inhibition of neurons, respectively. Recently, it was demonstrated that the point mutation gamma 2F77I causes a drastic change in the affinity of a variety of benzodiazepine agonists or inverse agonists in receptor binding studies. Here we investigated the potency and efficacy of 10 benzodiazepine site ligands from 6 structural classes in wild-type and gamma 2F77I point mutated recombinant GABA(A) receptors composed of alpha 1 beta 3 gamma 2, alpha 2 beta 3 gamma 2, alpha 3 beta 3 gamma 2, alpha 4 beta 3 gamma 2, alpha 5 beta 3 gamma 2, and alpha 6 beta 3 gamma 2 subunits. Results indicate that the effects of the benzodiazepine site ligands zolpidem, zopiclone, Cl218872, L-655,708 and DMCM were nearly completely eliminated in all mutated receptors up to a 1 microM concentration. The effects of bretazenil, Ro15-1788 or abecarnil were eliminated in some, but not all mutated receptors, suggesting that the gamma 2F77I mutation differentially influences the actions of these ligands in different receptor subtypes. In addition, this point mutation also influences the efficacy of diazepam for enhancing GABA-induced chloride flux, suggesting that the amino acid residue gamma 2F77 might also be involved in the transduction of the effect of benzodiazepines from binding to gating. The application of these drugs in a novel mouse model is discussed.
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Affiliation(s)
- Joachim Ramerstorfer
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Roman Furtmüller
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Elisabeth Vogel
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Sigismund Huck
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Werner Sieghart
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna, Spitalgasse 4, 1090 Vienna, Austria
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23
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Lorenz M, Kabir MS, Cook JM. A two step synthesis of BzR/GABAergic active flavones via a Wacker-related oxidation. Tetrahedron Lett 2010; 51:1095. [PMID: 20161661 DOI: 10.1016/j.tetlet.2009.12.107] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A general route for the synthesis of biologically important flavones is reported via a two step sequence employing a catalytic Wacker-Cook oxidation4b as the key step.
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Affiliation(s)
- Michael Lorenz
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
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24
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The differential role of alpha1- and alpha5-containing GABA(A) receptors in mediating diazepam effects on spontaneous locomotor activity and water-maze learning and memory in rats. Int J Neuropsychopharmacol 2009; 12:1179-93. [PMID: 19265570 PMCID: PMC2778330 DOI: 10.1017/s1461145709000108] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The clinical use of benzodiazepines (BZs) is hampered by sedation and cognitive deterioration. Although genetic and pharmacological studies suggest that alpha1- and alpha5-containing GABA(A) receptors mediate and/or modulate these effects, their molecular substrate is not fully elucidated. By the use of two selective ligands: the alpha1-subunit affinity-selective antagonist beta-CCt, and the alpha5-subunit affinity- and efficacy-selective antagonist XLi093, we examined the mechanisms of behavioural effects of diazepam in the tests of spontaneous locomotor activity and water-maze acquisition and recall, the two paradigms indicative of sedative- and cognition-impairing effects of BZs, respectively. The locomotor-activity decreasing propensity of diazepam (significant at 1.5 and 5 mg/kg) was antagonized by beta-CCt (5 and 15 mg/kg), while it tended to be potentiated by XLi093 in doses of 10 mg/kg, and especially 20 mg/kg. Diazepam decreased acquisition and recall in the water maze, with a minimum effective dose of 1.5 mg/kg. Both antagonists reversed the thigmotaxis induced by 2 mg/kg diazepam throughout the test, suggesting that both GABA(A) receptor subtypes participate in BZ effects on the procedural component of the task. Diazepam-induced impairment in the declarative component of the task, as assessed by path efficiency, the latency and distance before finding the platform across acquisition trials, and also by the spatial parameters in the probe trial, was partially prevented by both, 15 mg/kg beta-CCt and 10 mg/kg XLi093. Combining a BZ with beta-CCt results in the near to control level of performance of a cognitive task, without sedation, and may be worth testing on human subjects.
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25
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Zhang S, Cheng J, Liu Y, Xu L, Trudell ML, Izenwasser S, Wade D. Synthesis and nicotinic acetylcholine receptor affinity of bivalent tropane-3-carboxylates. J Heterocycl Chem 2009. [DOI: 10.1002/jhet.5570440629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Han D, Holger Försterling F, Li X, Deschamps JR, Parrish D, Cao H, Rallapalli S, Clayton T, Teng Y, Majumder S, Sankar S, Roth BL, Sieghart W, Furtmuller R, Rowlett JK, Weed MR, Cook JM. A study of the structure-activity relationship of GABA(A)-benzodiazepine receptor bivalent ligands by conformational analysis with low temperature NMR and X-ray analysis. Bioorg Med Chem 2008; 16:8853-62. [PMID: 18790643 DOI: 10.1016/j.bmc.2008.08.072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 08/21/2008] [Accepted: 08/28/2008] [Indexed: 11/29/2022]
Abstract
The stable conformations of GABA(A)-benzodiazepine receptor bivalent ligands were determined by low temperature NMR spectroscopy and confirmed by single crystal X-ray analysis. The stable conformations in solution correlated well with those in the solid state. The linear conformation was important for these dimers to access the binding site and exhibit potent in vitro affinity and was illustrated for alpha5 subtype selective ligands. Bivalent ligands with an oxygen-containing linker folded back upon themselves both in solution and the solid state. Dimers which are folded do not bind to Bz receptors.
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Affiliation(s)
- Dongmei Han
- Department of Chemistry, University of Wisconsin-Milwaukee, PO Box 413, Milwaukee, WI 53211, USA
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27
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Furtmueller R, Furtmueller B, Ramerstorfer J, Paladini AC, Wasowski C, Marder M, Huck S, Sieghart W. 6,3′-Dinitroflavone is a low efficacy modulator of GABAA receptors. Eur J Pharmacol 2008; 591:142-6. [DOI: 10.1016/j.ejphar.2008.06.093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Revised: 06/20/2008] [Accepted: 06/27/2008] [Indexed: 10/21/2022]
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28
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Jansen M, Rabe H, Strehle A, Dieler S, Debus F, Dannhardt G, Akabas MH, Lüddens H. Synthesis of GABAA receptor agonists and evaluation of their alpha-subunit selectivity and orientation in the GABA binding site. J Med Chem 2008; 51:4430-48. [PMID: 18651727 DOI: 10.1021/jm701562x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Drugs used to treat various disorders target GABA A receptors. To develop alpha subunit selective compounds, we synthesized 5-(4-piperidyl)-3-isoxazolol (4-PIOL) derivatives. The 3-isoxazolol moiety was substituted by 1,3,5-oxadiazol-2-one, 1,3,5-oxadiazol-2-thione, and substituted 1,2,4-triazol-3-ol heterocycles with modifications to the basic piperidine substituent as well as substituents without basic nitrogen. Compounds were screened by [(3)H]muscimol binding and in patch-clamp experiments with heterologously expressed GABA A alpha ibeta 3gamma 2 receptors (i = 1-6). The effects of 5-aminomethyl-3 H-[1,3,4]oxadiazol-2-one 5d were comparable to GABA for all alpha subunit isoforms. 5-piperidin-4-yl-3 H-[1,3,4]oxadiazol-2-one 5a and 5-piperidin-4-yl-3 H-[1,3,4]oxadiazol-2-thione 6a were weak agonists at alpha 2-, alpha 3-, and alpha 5-containing receptors. When coapplied with GABA, they were antagonistic in alpha 2-, alpha 4-, and alpha 6-containing receptors and potentiated alpha 3-containing receptors. 6a protected GABA binding site cysteine-substitution mutants alpha 1F64C and alpha 1S68C from reacting with methanethiosulfonate-ethylsulfonate. 6a specifically covalently modified the alpha 1R66C thiol, in the GABA binding site, through its oxadiazolethione sulfur. These results demonstrate the feasibility of synthesizing alpha subtype selective GABA mimetic drugs.
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Affiliation(s)
- Michaela Jansen
- Department of Medicinal Chemistry, Johannes Gutenberg-UniVersity, Mainz, Germany
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29
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Sieghart W. Structure, pharmacology, and function of GABAA receptor subtypes. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2006; 54:231-63. [PMID: 17175817 DOI: 10.1016/s1054-3589(06)54010-4] [Citation(s) in RCA: 224] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Werner Sieghart
- Division of Biochemistry and Molecular Biology, Center for Brain Research, and Section of Biochemical Psychiatry, University Clinic for Psychiatry, Medical University Vienna, Austria
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30
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Synthesis of bivalent ligands of β-carboline-3-carboxylates via a palladium-catalyzed homocoupling process. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.07.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Abstract
Drugs modulating gamma-aminobutyric acid (GABA) transmission via the benzodiazepine (BZ) site on the gamma-aminobutyric acid type A (GABAA) receptor have been in widespread use for more than 40 years to treat anxiety, epilepsy, and sleep disorders. These drugs have been shown to be safe, well tolerated, and effective although the mechanism by they produce a myriad of pharmacologic effects remains elusive. In recent years it has been discovered that, although the GABAA receptor is widely distributed in the brain, the substructure and composition of the receptor differs from between brain regions. Termed "GABAA receptor subtypes" their discovery leads to speculation that different subtypes may mediate specific effects of BZs such as anxiety or sedation. The phenotypic analysis of transgenic knock-in and knock-out mice in which particular GABAA receptors were rendered insensitive to the effects of BZ while others were unaffected confirmed this speculation. Subsequently, subtype-specific GABAA ligands were developed that, for example, retained the anxiolytic effects of BZs but were devoid of their sedative effects. Therefore, it may be possible to develop effective anxiolytic compounds that have a much reduced side-effect profile compared with existing drugs.
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Affiliation(s)
- Gerard R Dawson
- Merck Sharp & Dohme Research Laboratories, Terlings Park, Eastwick Road, Essex CM20 1QR, England
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32
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Han D, Försterling FH, Li X, Deschamps JR, Cao H, Cook JM. Determination of the stable conformation of GABA(A)-benzodiazepine receptor bivalent ligands by low temperature NMR and X-ray analysis. Bioorg Med Chem Lett 2004; 14:1465-9. [PMID: 15006383 DOI: 10.1016/j.bmcl.2004.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 12/23/2003] [Accepted: 01/10/2004] [Indexed: 11/19/2022]
Abstract
The stable conformations of GABA(A)-benzodiazepine receptor bivalent ligands 2 and 3 were determined by low temperature NMR spectroscopy and confirmed by single crystal X-ray analysis. The linear conformation was important for these dimers to access the binding site and exhibit potent in vitro affinity as illustrated for alpha5 subtype selective ligand 2 (15 nM). Bivalent ligand 3 with the 5 atom linker folded back upon itself both in solution and in the solid state, moreover, it did not bind to Bz receptors.
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Affiliation(s)
- Dongmei Han
- Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201, USA
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