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Casey AB, Mukherjee M, McGlynn RP, Cui M, Kohut SJ, Booth RG. A new class of serotonin 5-HT 2A /5-HT 2C receptor inverse agonists: Synthesis, molecular modeling, in vitro and in vivo pharmacology of novel 2-aminotetralins. Br J Pharmacol 2021; 179:2610-2630. [PMID: 34837227 DOI: 10.1111/bph.15756] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The 5-HT receptor (5-HTR) subtypes 5-HT2A and 5-HT2C are important neurotherapeutic targets, though, obtaining selectivity over 5-HT2B and closely related histamine H1 Rs is challenging. Here, we delineated molecular determinants of selective binding to 5-HT2A and 5-HT2C Rs for novel 4-phenyl-2-dimethylaminotetralins (4-PATs). EXPERIMENTAL APPROACH We synthesized 42 novel 4-PATs with halogen or aryl moieties at the C(4)-phenyl meta position. Affinity, function, molecular modeling, and 5-HT2A R mutagenesis studies were undertaken to understand structure-activity relationships at 5-HT2 -type and H1 Rs. Lead 4-PAT-type selective 5-HT2A /5-HT2C R inverse agonists were compared to pimavanserin, a selective 5-HT2A /5-HT2C R inverse agonist approved to treat psychoses, in the mouse head twitch response, and locomotor activity assays, as models relevant to antipsychotic drug development. KEY RESULTS Most 4-PAT diastereomers in the (2S,4R)-configuration bound non-selectively to 5-HT2A , 5-HT2C, and H1 Rs, with >100-fold selectivity over 5-HT2B Rs, whereas, diastereomers in the (2R,4R)-configuration bound preferentially to 5-HT2A over 5-HT2C Rs and had >100-fold selectivity over 5-HT2B and H1 Rs. Results suggest that G2385.42 and V2355.39 in 5-HT2A Rs (conserved in 5-HT2C Rs) are important for high affinity binding, whereas, interactions with T1945.42 and W1584.56 determine H1 R affinity. The 4-PAT (2S,4R)-2k, a potent and selective 5-HT2A /5-HT2C R inverse agonist, had activity like pimavanserin in the mouse head-twitch response assay, but was distinct in not suppressing locomotor activity. CONCLUSIONS AND IMPLICATIONS We provide evidence that the novel 4-PAT chemotype can yield selective 5-HT2A /5-HT2C R inverse agonists for antipsychotic drug development by optimizing ligand-receptor interactions in transmembrane domain 5. We also show that chirality can be exploited to attain selectivity over H1 Rs which may circumvent sedative effects.
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Affiliation(s)
- Austen B Casey
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Munmun Mukherjee
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Ryan P McGlynn
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
| | - Meng Cui
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States
| | - Stephen J Kohut
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Behavioral Neuroimaging Laboratory, McLean Hospital and Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts, United States
| | - Raymond G Booth
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States.,Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States.,Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts, United States
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Perry CK, Casey AB, Felsing DE, Vemula R, Zaka M, Herrington NB, Cui M, Kellogg GE, Canal CE, Booth RG. Synthesis of novel 5-substituted-2-aminotetralin analogs: 5-HT1A and 5-HT7 G protein-coupled receptor affinity, 3D-QSAR and molecular modeling. Bioorg Med Chem 2020; 28:115262. [DOI: 10.1016/j.bmc.2019.115262] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/21/2019] [Accepted: 12/09/2019] [Indexed: 11/30/2022]
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Felsing DE, Canal CE, Booth RG. Ligand-directed serotonin 5-HT 2C receptor desensitization and sensitization. Eur J Pharmacol 2019; 848:131-139. [PMID: 30689993 DOI: 10.1016/j.ejphar.2019.01.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022]
Abstract
Exposure of G protein-coupled receptors (GPCRs) to agonists can desensitize receptor signaling and lead to drug tolerance, whereas inverse agonists can sensitize signaling. For example, activation of serotonin 5-HT2C GPCRs is pharmacotherapeutic for obesity, but there is tolerance to the anorectic effect of the only approved 5-HT2C agonist, lorcaserin. We tested the hypothesis that different agonists or inverse agonists differentially desensitize or sensitize, respectively, canonical 5-HT2C-mediated activation of phospholipase C (PLC) signaling in vitro. Lorcaserin, which displays potency and efficacy equal to 5-HT, desensitized the 5-HT2C receptor significantly more than 5-HT (p<0.05). Agonist chemotypes such as 2-aminotetralins, with similar potency but lower efficacy than 5-HT, produced little 5-HT2C desensitization. The piperazine agonist 1-(3-chlorophenyl)piperazine (mCPP), with lower potency but similar efficacy as 5-HT, elicited desensitization indistinguishable from 5-HT, while the piperazine agonist aripiprazole, with lower potency and efficacy, did not desensitize 5-HT2C-PLC signaling. Several 5-HT2C agonists also were assessed for β-arrestin recruitment-lorcaserin was a 'super-agonist', but a 2-aminotetralin and aripiprazole had nil activity, suggesting they are biased towards 5-HT2C-PLC signaling. We observed robust positive correlations between the magnitude of 5-HT2C desensitization and agonist efficacy to stimulate PLC or to recruit β-arrestin. In contrast, different inverse agonists caused different magnitudes of 5-HT2C sensitization that did not correlate with efficacy (or potency) to inhibit constitutive 5-HT2C-PLC signaling. Assessment of the 5-HT2C-S407A point-mutated receptor indicated this residue's involvement in ligand-dependent desensitization, but we did not observe a role for protein kinase C.These data show that ligand structure uniquely impacts 5-HT2C desensitization and sensitization processes..
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Affiliation(s)
- Daniel E Felsing
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, United States; Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610, United States.
| | - Clinton E Canal
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, United States.
| | - Raymond G Booth
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, United States; Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, United States; Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610, United States.
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Liu Y, Canal CE, Cordova-Sintjago TC, Zhu W, Booth RG. Mutagenesis Analysis Reveals Distinct Amino Acids of the Human Serotonin 5-HT 2C Receptor Underlying the Pharmacology of Distinct Ligands. ACS Chem Neurosci 2017; 8:28-39. [PMID: 27580242 DOI: 10.1021/acschemneuro.6b00124] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
While exploring the structure-activity relationship of 4-phenyl-2-dimethylaminotetralins (PATs) at serotonin 5-HT2C receptors, we discovered that relatively minor modification of PAT chemistry impacts function at 5-HT2C receptors. In HEK293 cells expressing human 5-HT2C-INI receptors, for example, (-)-trans-3'-Br-PAT and (-)-trans-3'-Cl-PAT are agonists regarding Gαq-inositol phosphate signaling, whereas (-)-trans-3'-CF3-PAT is an inverse agonist. To investigate the ligand-receptor interactions that govern this change in function, we performed site-directed mutagenesis of 14 amino acids of the 5-HT2C receptor based on molecular modeling and reported G protein-coupled receptor crystal structures, followed by molecular pharmacology studies. We found that S3.36, T3.37, and F5.47 in the orthosteric binding pocket are critical for affinity (Ki) of all PATs tested, we also found that F6.44, M6.47, C7.45, and S7.46 are primarily involved in regulating EC/IC50 functional potencies of PATs. We discovered that when residue S5.43, N6.55, or both are mutated to alanine, (-)-trans-3'-CF3-PAT switches from inverse agonist to agonist function, and when N6.55 is mutated to leucine, (-)-trans-3'-Br-PAT switches from agonist to inverse agonist function. Notably, most point-mutations that affected PAT pharmacology did not significantly alter affinity (KD) of the antagonist radioligand [3H]mesulergine, but every mutation tested negatively impacted serotonin binding. Also, amino acid mutations differentially affected the pharmacology of other commercially available 5-HT2C ligands tested. Collectively, the data show that functional outcomes shared by different ligands are mediated by different amino acids and that some 5-HT2C receptor residues important for pharmacology of one ligand are not necessarily important for another ligand.
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Affiliation(s)
- Yue Liu
- Center
for Drug Discovery, Department of Pharmaceutical Sciences, and Department
of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Clinton E. Canal
- Center
for Drug Discovery, Department of Pharmaceutical Sciences, and Department
of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Tania C. Cordova-Sintjago
- Center
for Drug Discovery, Department of Pharmaceutical Sciences, and Department
of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Department
of Medicinal Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Wanying Zhu
- Center
for Drug Discovery, Department of Pharmaceutical Sciences, and Department
of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Raymond G. Booth
- Center
for Drug Discovery, Department of Pharmaceutical Sciences, and Department
of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
- Department
of Medicinal Chemistry, University of Florida, Gainesville, Florida 32611, United States
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