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Lee KH, Camacho-Hernandez GA, Newman AH, Shi L. The Structural Basis of the Activity Cliff in Modafinil-Based Dopamine Transporter Inhibitors. Biomolecules 2024; 14:713. [PMID: 38927116 PMCID: PMC11202288 DOI: 10.3390/biom14060713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/01/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
Modafinil analogs with either a sulfoxide or sulfide moiety have improved binding affinities at the human dopamine transporter (hDAT) compared to modafinil, with lead sulfoxide-substituted analogs showing characteristics of atypical inhibition (e.g., JJC8-091). Interestingly, the only distinction between sulfoxide and sulfide substitution is the presence of one additional oxygen atom. To elucidate why such a subtle difference in ligand structure can result in different typical or atypical profiles, we investigated two pairs of analogs. Our quantum mechanical calculations revealed a more negatively charged distribution of the electrostatic potential surface of the sulfoxide substitution. Using molecular dynamics simulations, we demonstrated that sulfoxide-substituted modafinil analogs have a propensity to attract more water into the binding pocket. They also exhibited a tendency to dissociate from Asp79 and form a new interaction with Asp421, consequently promoting an inward-facing conformation of hDAT. In contrast, sulfide-substituted analogs did not display these effects. These findings elucidate the structural basis of the activity cliff observed with modafinil analogs and also enhance our understanding of the functionally relevant conformational spectrum of hDAT.
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Affiliation(s)
| | | | | | - Lei Shi
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse–Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA; (K.-H.L.); (G.A.C.-H.); (A.H.N.)
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2
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Ecevitoglu A, Meka N, Rotolo RA, Edelstein GA, Srinath S, Beard KR, Carratala-Ros C, Presby RE, Cao J, Okorom A, Newman AH, Correa M, Salamone JD. Potential therapeutics for effort-related motivational dysfunction: assessing novel atypical dopamine transport inhibitors. Neuropsychopharmacology 2024:10.1038/s41386-024-01826-1. [PMID: 38429498 DOI: 10.1038/s41386-024-01826-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/28/2024] [Accepted: 02/05/2024] [Indexed: 03/03/2024]
Abstract
People with depression and other neuropsychiatric disorders can experience motivational dysfunctions such as fatigue and anergia, which involve reduced exertion of effort in goal-directed activity. To model effort-related motivational dysfunction, effort-based choice tasks can be used, in which rats can select between obtaining a preferred reinforcer by high exertion of effort vs. a low effort/less preferred option. Preclinical data indicate that dopamine transport (DAT) inhibitors can reverse pharmacologically-induced low-effort biases and increase selection of high-effort options in effort-based choice tasks. Although classical DAT blockers like cocaine can produce undesirable effects such as liability for misuse and psychotic reactions, not all DAT inhibitors have the same neurochemical profile. The current study characterized the effort-related effects of novel DAT inhibitors that are modafinil analogs and have a range of binding profiles and neurochemical actions (JJC8-088, JJC8-089, RDS3-094, and JJC8-091) by using two different effort-related choice behavior tasks in male Sprague-Dawley rats. JJC8-088, JJC8-089, and RDS3-094 significantly reversed the low-effort bias induced by the VMAT-2 inhibitor tetrabenazine, increasing selection of high-effort fixed ratio 5 lever pressing vs. chow intake. In addition, JJC8-089 reversed the effects of tetrabenazine in female rats. JJC8-088 and JJC8-089 also increased selection of high-effort progressive ratio responding in a choice task. However, JJC8-091 failed to produce these outcomes, potentially due to its unique pharmacological profile (i.e., binding to an occluded conformation of DAT). Assessment of a broad range of DAT inhibitors with different neurochemical characteristics may lead to the identification of compounds that are useful for treating motivational dysfunction in humans.
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Affiliation(s)
- Alev Ecevitoglu
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Nicolette Meka
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Renee A Rotolo
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Gayle A Edelstein
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Sonya Srinath
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Kathryn R Beard
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Carla Carratala-Ros
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
- Area de Psicobiología. Universitat Jaume I, Castelló, Spain
| | - Rose E Presby
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Jianjing Cao
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Amarachi Okorom
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Amy H Newman
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Mercè Correa
- Area de Psicobiología. Universitat Jaume I, Castelló, Spain
| | - John D Salamone
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA.
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Okorom AV, Camacho-Hernandez GA, Salomon K, Lee KH, Ku TC, Cao J, Won SJ, Friedman J, Lam J, Paule J, Rais R, Klein B, Xi ZX, Shi L, Loland CJ, Newman AH. Modifications to 1-(4-(2-Bis(4-fluorophenyl)methyl)sulfinyl)alkyl Alicyclic Amines That Improve Metabolic Stability and Retain an Atypical DAT Inhibitor Profile. J Med Chem 2024; 67:709-727. [PMID: 38117239 DOI: 10.1021/acs.jmedchem.3c02037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Atypical dopamine transporter (DAT) inhibitors have shown therapeutic potential in the preclinical models of psychostimulant use disorders (PSUD). In rats, 1-(4-(2-((bis(4-fluorophenyl)methyl)sulfinyl)ethyl)-piperazin-1-yl)-propan-2-ol (JJC8-091, 3b) was effective in reducing the reinforcing effects of both cocaine and methamphetamine but did not exhibit psychostimulant behaviors itself. Improvements in DAT affinity and metabolic stability were desirable for discovering pipeline drug candidates. Thus, a series of 1-(4-(2-bis(4-fluorophenyl)methyl)sulfinyl)alkyl alicyclic amines were synthesized and evaluated for binding affinities at DAT and the serotonin transporter (SERT). Replacement of the piperazine with either a homopiperazine or a piperidine ring system was well tolerated at DAT (Ki range = 3-382 nM). However, only the piperidine analogues (20a-d) showed improved metabolic stability in rat liver microsomes as compared to the previously reported analogues. Compounds 12b and 20a appeared to retain an atypical DAT inhibitor profile, based on negligible locomotor activity in mice and molecular modeling that predicts binding to an inward-facing conformation of DAT.
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Affiliation(s)
- Amarachi V Okorom
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Gisela Andrea Camacho-Hernandez
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Kristine Salomon
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Kuo Hao Lee
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Therese C Ku
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Jianjing Cao
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Sung Joon Won
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Jacob Friedman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Jenny Lam
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - James Paule
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Rana Rais
- Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Benjamin Klein
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Zheng-Xiong Xi
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Lei Shi
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Claus J Loland
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Amy Hauck Newman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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Allen MI, Johnson BN, Nader MA. A comparison of the reinforcing strength of cocaethylene and cocaine in monkeys responding under progressive-ratio and concurrent choice schedules of reinforcement. Drug Alcohol Depend 2023; 251:110952. [PMID: 37699287 PMCID: PMC10538368 DOI: 10.1016/j.drugalcdep.2023.110952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND Individuals who use cocaine have high rates of co-morbid alcohol use and when ethanol and cocaine are administered concurrently, the metabolite cocaethylene is formed. Cocaethylene is equipotent to cocaine in blocking dopamine reuptake and substitutes for cocaine in drug discrimination studies. However, no previous work has directly compared the reinforcing strength of cocaine to cocaethylene. METHODS In Experiment 1, three individually-housed adult male rhesus macaques self-administer cocaine under a progressive-ratio (PR) schedule of reinforcement, during daily 4-hr sessions. Under this schedule, the primary dependent variable is the number of injections received, or the break point (BP). Saline, cocaine (0.001-0.3mg/kg/injection) and cocaethylene (0.0003-0.1mg/kg/injection) dose-response curves were determined. In Experiment 2, two female cynomolgus and one rhesus macaque responded under a concurrent schedule of drug (cocaine or cocaethylene) vs. 1.0-g banana-flavored food pellets, during daily 1-hr sessions. RESULTS Both cocaine and cocaethylene functioned as reinforcers under the PR and concurrent choice schedules of reinforcement. Under the PR schedule, peak BPs were not significantly different, nor were ED50 values on the ascending limb, suggesting that cocaethylene has equal reinforcing strength and potency to cocaine. Under the concurrent drug-food choice procedure, cocaethylene was also equally potent to cocaine. CONCLUSIONS Under two schedules of reinforcement designed to assess reinforcing strength, cocaethylene and cocaine were equipotent and of equal reinforcing strength. Because cocaethylene has a longer duration of action, it is important for studies designed to evaluate treatments for cocaine use to also consider the effects of these interventions on cocaethylene.
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Affiliation(s)
- Mia I Allen
- Department of Physiology and Pharmacology, Graduate Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Bernard N Johnson
- Department of Physiology and Pharmacology, Graduate Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Michael A Nader
- Department of Physiology and Pharmacology, Graduate Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Hersey M, Chen AY, Bartole MK, Anand J, Newman AH, Tanda G. An FSCV Study on the Effects of Targeted Typical and Atypical DAT Inhibition on Dopamine Dynamics in the Nucleus Accumbens Shell of Male and Female Mice. ACS Chem Neurosci 2023; 14:2802-2810. [PMID: 37466616 PMCID: PMC10766117 DOI: 10.1021/acschemneuro.3c00354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Understanding the neurochemistry underlying sex differences in psychostimulant use disorders (PSUD) is essential for developing related therapeutics. Many psychostimulants, like cocaine, inhibit the dopamine transporter (DAT), which is largely thought to account for actions related to their misuse and dependence. Cocaine-like, typical DAT inhibitors preferentially bind DAT in an outward-facing conformation, while atypical DAT inhibitors, like modafinil, prefer a more inward-facing DAT conformation. Modafinil and R-modafinil have emerged as potential therapeutic options for selected populations of individuals affected by PSUD. In addition, analogs of modafinil (JJC8-088 and JJC8-091) with different pharmacological profiles have been explored as potential PSUD medications in preclinical models. In this work, we employ fast scan cyclic voltammetry (FSCV) to probe nucleus accumbens shell (NAS) dopamine (DA) dynamics in C57BL/6 male and female mice. We find that cocaine slowed DA clearance in both male and female mice but produced more robust increases in evoked NAS DA in female mice. R-Modafinil produced mild increases in evoked NAS DA and slowed DA clearance across the sexes. The modafinil analog JJC8-088, a typical DAT inhibitor, produced increases in evoked NAS DA in female and male mice. Finally, JJC8-091, an atypical DAT inhibitor, produced limited increases in evoked NAS DA and slowed DA clearance in both sexes. In this work we begin to tease out how sex differences may alter the effects of DAT targeting and highlight how this may help focus research toward effective treatment options for PSUD.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, NIDA IRP, Baltimore, MD 21224
| | - Andy Y. Chen
- Medication Development Program, NIDA IRP, Baltimore, MD 21224
| | | | - Jayati Anand
- Medication Development Program, NIDA IRP, Baltimore, MD 21224
| | - Amy Hauck Newman
- Medication Development Program, NIDA IRP, Baltimore, MD 21224
- Medicinal Chemistry Section, NIDA IRP, Baltimore, MD 21224
| | - Gianluigi Tanda
- Medication Development Program, NIDA IRP, Baltimore, MD 21224
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Hersey M, Bartole MK, Jones CS, Newman AH, Tanda G. Are There Prevalent Sex Differences in Psychostimulant Use Disorder? A Focus on the Potential Therapeutic Efficacy of Atypical Dopamine Uptake Inhibitors. Molecules 2023; 28:5270. [PMID: 37446929 DOI: 10.3390/molecules28135270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
Psychostimulant use disorders (PSUD) affect a growing number of men and women and exert sizable public health and economic burdens on our global society. Notably, there are some sex differences in the onset of dependence, relapse rates, and treatment success with PSUD observed in preclinical and clinical studies. The subtle sex differences observed in the behavioral aspects of PSUD may be associated with differences in the neurochemistry of the dopaminergic system between sexes. Preclinically, psychostimulants have been shown to increase synaptic dopamine (DA) levels and may downregulate the dopamine transporter (DAT). This effect is greatest in females during the high estradiol phase of the estrous cycle. Interestingly, women have been shown to be more likely to begin drug use at younger ages and report higher levels of desire to use cocaine than males. Even though there is currently no FDA-approved medication, modafinil, a DAT inhibitor approved for use in the treatment of narcolepsy and sleep disorders, has shown promise in the treatment of PSUD among specific populations of affected individuals. In this review, we highlight the therapeutic potential of modafinil and other atypical DAT inhibitors focusing on the lack of sex differences in the actions of these agents.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | | | - Claire S Jones
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Amy Hauck Newman
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Gianluigi Tanda
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
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