1
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Walby GD, Gu Q, Yang H, Martin SF. Structure-Affinity relationships of novel σ 2R/TMEM97 ligands. Bioorg Chem 2024; 145:107191. [PMID: 38432153 DOI: 10.1016/j.bioorg.2024.107191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/24/2024] [Accepted: 02/06/2024] [Indexed: 03/05/2024]
Abstract
The sigma 2 receptor (σ2R), which was recently identified as the transmembrane protein 97 (TMEM97), is increasingly attracting interest as a possible therapeutic target for indications in neuroscience. Toward identifying novel modulators of σ2R/TMEM97, we prepared a collection of benzoxazocine, benzomorphan, and methanobenzazepine ligands related to the known bioactive norbenzomorphans DKR-1677, FEM-1689, and EES-1686 and determined their Ki values for σ2R/TMEM97 and the sigma 1 receptor (σ1R). The σ2R/TMEM97 binding affinities and selectivities relative to σ1R of these new benzoxazocine, benzomorphan, and methanobenzazepine analogs are lower, often significantly lower, than their respective norbenzomorphan counterparts, suggesting the spatial orientation of pharmacophoric substituents is critical for binding to the two proteins. The benzoxazocine, benzomorphan, and methanobenzazepine congeners of DKR-1677 and FEM-1689 tend to be weakly selective for σ2R/TMEM97 versus σ1R, whereas EES-1686 derivatives exhibit the greatest selectivity, suggesting the size and/or nature of the substituent on the nitrogen atom of the scaffold may be important for selectivity. Computational docking studies were performed for the 1S,5R-and 1R,5S-enantiomers of DKR-1677, FEM-1689, and EES-1686 and their benzoxazocine, benzomorphan, and methanobenzazepine counterparts. These computations predict that the protonated amino group of each ligand forms a highly conserved salt bridge and a H-bonding interaction with Asp29 as well as a cation-π interaction with Tyr150 of σ2R/TMEM97. These electrostatic interactions are major driving forces for binding to σ2R/TMEM97 and are similar, though not identical, for each ligand. Other interactions within the well-defined binding pocket also tend to be comparable, but there are some major differences in how the hydrophobic aryl groups of various ligands interact with the protein surface external to the binding pocket. Overall, these studies show that the orientations of aryl and N-substituents on the norbenzomorphan and related scaffolds are important determinants of binding affinity of σ2R/TMEM97 ligands, and small changes can have significant effects upon binding profiles.
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Affiliation(s)
- Grant D Walby
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Qi Gu
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Hongfen Yang
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, United States.
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2
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Lu Y, Gu Q, Martin SF. Structure-affinity relationships of stereoisomers of norbenzomorphan-derived σ 2R/TMEM97 modulators. Eur J Med Chem 2023; 257:115488. [PMID: 37247506 DOI: 10.1016/j.ejmech.2023.115488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/24/2023] [Accepted: 05/13/2023] [Indexed: 05/31/2023]
Abstract
The sigma 2 receptor (σ2R), which is identical to transmembrane protein 97 (TMEM97), is attracting increasing interest as a possible therapeutic target for various indications in neuroscience. In continuation of a program to identify novel compounds that bind with high affinity and selectivity to σ2R/TMEM97, we performed structure-affinity-relationship (SAfiR) studies of several sets of σ2R/TMEM97 ligands having a B-norbenzomorphan ring core. Binding data for σ2R/TMEM97 and σ1R of several enantiomeric pairs of piperazine-substituted norbenzomorphans show the (1S,5R)-enantiomers have affinities (Ki = 9-75 nM) for σ2R/TMEM97 that are 2-3-fold higher than their enantiomorphic (1R,5S)-analogs; however, there is no clear trend for selectivity for σ2R/TMEM97 vs σ1R. A series of N-alkyl piperazino (1S,5R)-norbenzomorphans was then evaluated, and with the exception of compounds having N-alkyl groups substituted with oxygen or amino groups at C (2) of an ethylene chain, Ki values for σ2R/TMEM97 are less than 25 nM, and several compounds have good selectivities (ca 7-16-fold) for σ2R/TMEM97 vs σ1R. Mono-substituted carbobenzyloxy analogs have Ki values for σ2R/TMEM97 comparable to the unsubstituted parent (Ki = ca 7-27 nM), but replacing the N-acyloxy group with N-acyl or N-arylsulfonyl groups provides analogs having lower affinity and selectivity. Some congeners with bioisosteric replacements of the piperazine group on the (1S,5R)-norbenzomorphan core have high affinity (Ki = <30 nM) for σ2R/TMEM97, but selectivities are modest. Computational docking studies for racemic pairs of piperazino norbenzomorphans show that individual (1S,5R)- and (1R,5S)-enantiomers adopt distinct poses upon binding to σ2R/TMEM97, whereas ligands belongingto the same enantiomeric series adopt closely similar binding poses. The protonated amino group in each of the enantiomorphic ligands engages in highly conserved salt bridges with Asp29 and cation-π interactions with Tyr150 that are the primary determinants of binding affinity. There is no correlation between any of the computational parameter outputs and Ki values, but this is unsurprising given the small energetic differences involved. Modeling also suggest sthat some compounds can extend deeper into σ2R/TMEM97 binding pocket forming salt bridges with Glu73.
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Affiliation(s)
- Yan Lu
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Qi Gu
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States.
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3
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Jin J, Arbez N, Sahn JJ, Lu Y, Linkens KT, Hodges TR, Tang A, Wiseman R, Martin SF, Ross CA. Neuroprotective Effects of σ 2R/TMEM97 Receptor Modulators in the Neuronal Model of Huntington's Disease. ACS Chem Neurosci 2022; 13:2852-2862. [PMID: 36108101 PMCID: PMC9547941 DOI: 10.1021/acschemneuro.2c00274] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disease caused by an expanded CAG repeat in the Huntingtin (HTT) gene that encodes for an expanded polyglutamine (polyQ) repeat in exon-1 of the human mutant huntingtin (mHTT) protein. The presence of this polyQ repeat results in neuronal degeneration, for which there is no cure or treatment that modifies disease progression. In previous studies, we have shown that small molecules that bind selectively to σ2R/TMEM97 can have significant neuroprotective effects in models of Alzheimer's disease, traumatic brain injury, and several other neurodegenerative diseases. In the present work, we extend these investigations and show that certain σ2R/TMEM97-selective ligands decrease mHTT-induced neuronal toxicity. We first synthesized a set of compounds designed to bind to σ2R/TMEM97 and determined their binding profiles (Ki values) for σ2R/TMEM97 and other proteins in the central nervous system. Modulators with high affinity and selectivity for σ2R/TMEM97 were then tested in our HD cell model. Primary cortical neurons were cultured in vitro for 7 days and then co-transfected with either a normal HTT construct (Htt N-586-22Q/GFP) or the mHTT construct Htt-N586-82Q/GFP. Transfected neurons were treated with either σ2R/TMEM97 or σ1R modulators for 48 h. After treatment, neurons were fixed and stained with Hoechst, and condensed nuclei were quantified to assess cell death in the transfected neurons. Significantly, σ2R/TMEM97 modulators reduce the neuronal toxicity induced by mHTT, and their neuroprotective effects are not blocked by NE-100, a selective σ1R antagonist known to block neuroprotection by σ1R ligands. These results indicate for the first time that σ2R/TMEM97 modulators can protect neurons from mHTT-induced neuronal toxicity, suggesting that targeting σ2R/TMEM97 may lead to a novel therapeutic approach to treat patients with HD.
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Affiliation(s)
- Jing Jin
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore Maryland, 21287, United States
| | - Nicolas Arbez
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore Maryland, 21287, United States
- Cellular Sciences Department, IdRS, Croissy-sur-Seine, France
| | - James J. Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Yan Lu
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Kathryn T. Linkens
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Timothy R. Hodges
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Anthony Tang
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore Maryland, 21287, United States
| | - Robyn Wiseman
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore Maryland, 21287, United States
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, United States
| | - Stephen F. Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712, United States
| | - Christopher A. Ross
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore Maryland, 21287, United States
- Departments of Neurology, Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, United States
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4
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Martin SF. Bridging Known and Unknown Unknowns: From Natural Products and Their Mimics to Unmet Needs in Neuroscience. Acc Chem Res 2022; 55:2397-2408. [PMID: 35960884 DOI: 10.1021/acs.accounts.1c00773] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Scientific excursions into the unknown are often characterized by unanticipated twists and turns that may lead in directions that never could have been predicted. Decisions made during the course of these explorations determine what we discover. This Account chronicles one such journey that began with a challenge encountered during the synthesis of a natural product and then unfolded over more than 30 years to focus on unmet needs in neuroscience. Specifically, while developing a concise approach to tetrahydroalstonine, a heteroyohimboid alkaloid having α-adrenergic activity, we faced the predicament of assembling a key intermediate. Solving this problem resulted in the serendipitous discovery of the vinylogous Mannich reaction and a productive program wherein we used this powerful construction as a key step in the syntheses of numerous alkaloids. However, we also realized that lessons learned from the synthesis of tetrahydroalstonine could be generalized to invent a new strategy for preparing diverse collections of substituted nitrogen heterocycles that could be screened against biological targets. The approach featured the combination of several reactants in a multicomponent assembly process to give a functionalized intermediate that could be elaborated by various ring-forming reactions to give heterocyclic scaffolds that could be further diversified. Screening these compound sets against a broad range of biological targets revealed some intriguing hits, but none of them led to a productive collaboration in translational research. Notwithstanding this setback, we screened curated members of our collections against proteins in the central nervous system and discovered some substituted B-norbenzomorphans that were selective for the enigmatic sigma-2 receptor (σ2R), an understudied protein that had been primarily associated with cancer. With scant knowledge of its role in neuroscience, we posited that small molecules that bind to σ2R might be neuroprotective, thus launching a new venture. In parallel investigations we prepared analogues of the initial hits, explored their effects in animal models of neurodegenerative and neurological conditions, and identified σ2R as transmembrane protein 97 (TMEM97). After first establishing the neuroprotective effects of several σ2R/TMEM97 ligands in a transgenic Caenorhabditis elegans model of neurodegeneration, we showed that one of these has procognitive effects and reduces levels of proinflammatory cytokines in a transgenic mouse model of Alzheimer's disease. We then identified a closely related σ2R/TMEM97 ligand that mitigates hippocampal-dependent memory deficits, prevents axon degeneration, and protects neurons and oligodendrocytes after traumatic brain injury. In a recent study, this compound was shown to protect retinal ganglion cells from retinal ischemia/reperfusion injury. In other collaborative investigations, we have shown that related, but structurally distinct, σ2R/TMEM97 ligands alleviate neuropathic pain, while a σ2R/TMEM97 ligand representing yet another chemotype reduces impairments associated with alcohol withdrawal. More recently, we have shown that σ2R/TMEM97 ligands enhance survival of cortical neurons in a neuronal model of Huntington's disease. Translational and mechanistic studies in these and other areas are in progress. Solving a problem we faced in natural product synthesis thus served as an unexpected gateway to discoveries that could lead to entirely new approaches to treat neurodegenerative and neurological conditions by targeting σ2R/TMEM97, a protein that has never been associated with these afflictions.
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Affiliation(s)
- Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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5
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Targeting σ2R/TMEM97 with novel aminotetralins. Eur J Med Chem 2022; 243:114696. [DOI: 10.1016/j.ejmech.2022.114696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022]
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6
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Preparation of novel analogs of 2-arylpiperidines and evaluation of their sigma receptor binding affinities. Eur J Med Chem 2022; 235:114310. [DOI: 10.1016/j.ejmech.2022.114310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/18/2022]
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7
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Xie XY, Li YY, Ma WH, Chen AF, Sun YT, Lee JY, Riad A, Xu DH, Mach RH, Huang YS. Synthesis, binding, and functional properties of tetrahydroisoquinolino-2-alkyl phenones as selective σ 2R/TMEM97 ligands. Eur J Med Chem 2021; 209:112906. [PMID: 33049607 DOI: 10.1016/j.ejmech.2020.112906] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/01/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023]
Abstract
Sigma-2 receptor (σ2R/TMEM97) has been implicated to play important roles in multiple cellular dysfunctions, such as cell neoplastic proliferation, neuro-inflammation, neurodegeneration, etc. Selective σ2 ligands are believed to be promising pharmacological tools to regulate or diagnose various disorders. As an ongoing effort of discovery of new and selective σ2 ligands, we have synthesized a series of tetrahydroisoquinolino-2-alkyl phenone analogs and identified that 10 of them have moderate to potent affinity and selectivity for σ2R/TMEM97. Especially, 4 analogs showed Ki values ranging from 0.38 to 5.1 nM for σ2R/TMEM97 with no or low affinity for sigma-1 receptor (σ1R). Functional assays indicated that these 4 most potent analogs had no effects on intracellular calcium concentration and were classified as putative σ2R/TMEM97 antagonists according to current understanding. The σ2R/TMEM97 has been suggested to play important roles in the central nervous system. Based on published pharmacological and clinical results from several regarded σ2R/TMEM97 antagonists, these analogs may potentially be useful for the treatment of various neurodegenerative diseases.
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Affiliation(s)
- Xiao-Yang Xie
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Yu-Yun Li
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Wen-Hui Ma
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Ai-Fang Chen
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Yu-Tong Sun
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Ji Youn Lee
- Department of Radiology, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA
| | - Aladdin Riad
- Department of Radiology, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA
| | - Dao-Hua Xu
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China
| | - Robert H Mach
- Department of Radiology, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA.
| | - Yun-Sheng Huang
- School of Pharmacy, Guangdong Medical University, 1 Xincheng Ave, Songshan Lake Technology Park, Dongguan, Guangdong 523808, China.
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8
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Greenfield DA, Schmidt HR, Skiba MA, Mandler MD, Anderson JR, Sliz P, Kruse AC. Virtual Screening for Ligand Discovery at the σ 1 Receptor. ACS Med Chem Lett 2020; 11:1555-1561. [PMID: 32832023 DOI: 10.1021/acsmedchemlett.9b00314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/27/2020] [Indexed: 01/04/2023] Open
Abstract
The σ1 receptor is a transmembrane protein implicated in several pathophysiological conditions, including neurodegenerative disease (J. Pharmacol. Sci.2015127 (1), 1729), drug addiction (Behav. Pharmacol.201627 (2-3 Spec Issue), 10015), cancer (Handb. Exp. Pharmacol.2017244237308), and pain (Neural Regener. Res.201813 (5), 775778). However, there are no high-throughput functional assays for σ1 receptor drug discovery. Here, we assessed high-throughput structure-based computational docking for discovery of novel ligands of the σ1 receptor. We screened a library of over 6 million compounds using the Schrödinger Glide package, followed by experimental characterization of top-scoring candidates. 77% of tested candidates bound σ1 with high affinity (KD < 1 μM). These include compounds with high selectivity for the σ1 receptor compared to the genetically unrelated but pharmacologically similar σ2 receptor, as well as compounds with substantial crossreactivity between the two receptors. These results establish structure-based virtual screening as a highly effective platform for σ1 receptor ligand discovery and provide compounds to prioritize in studies of σ1 biology.
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Affiliation(s)
- Daniel A. Greenfield
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
| | - Hayden R. Schmidt
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
| | - Meredith A. Skiba
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
| | - Michael D. Mandler
- Harvard University, Department of Chemistry and Chemical Biology, Cambridge, Massachusetts 02138, United States
| | - Jacob R. Anderson
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
| | - Piotr Sliz
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
- Boston Children’s Hospital, Boston, Massachusetts 02115, United States
| | - Andrew C. Kruse
- Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology, Boston, Massachusetts 02115, United States
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9
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Ma JT, Cheng Y. Construction of enantiopure imine bridged benzo[c]azepinones by a silver(i) and chiral N-heterocyclic carbene multicatalytic reaction sequence of N′-(2-alkynylbenzylidene)hydrazides and cyclopropanecarbaldehydes. Org Chem Front 2020. [DOI: 10.1039/d0qo00877j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel and efficient method for the synthesis of enantiopure bridged benzo[c]azepinone compounds has been developed by metal/N-heterocyclic carbene multicatalysis.
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Affiliation(s)
- Jin-Tao Ma
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
| | - Ying Cheng
- College of Chemistry
- Beijing Normal University
- Beijing 100875
- China
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10
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Iyamu ID, Lv W, Malik N, Mishra RK, Schiltz GE. Development of Tetrahydroindazole-Based Potent and Selective Sigma-2 Receptor Ligands. ChemMedChem 2019; 14:1248-1256. [PMID: 31071238 PMCID: PMC6613831 DOI: 10.1002/cmdc.201900203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/08/2019] [Indexed: 11/08/2022]
Abstract
The sigma-2 receptor has been shown to play important roles in a number of important diseases, including central nervous system (CNS) disorders and cancer. However, mechanisms by which sigma-2 contributes to these diseases remain unclear. The development of new sigma-2 ligands that can be used to probe the function of this protein and potentially as drug discovery leads is therefore of great importance. Herein we report the development of a series of tetrahydroindazole compounds that are highly potent and selective for sigma-2. Structure-activity relationship data were used to generate a pharmacophore model that summarizes the common features present in the potent ligands. Assays for solubility and microsomal stability showed that several members of this compound series possess promising characteristics for further development of useful chemical probes or drug discovery leads.
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Affiliation(s)
- Iredia D Iyamu
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, 60208, USA
| | - Wei Lv
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, 60208, USA
| | - Neha Malik
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, 60208, USA
| | - Rama K Mishra
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, 60208, USA
- Department of Pharmacology, Northwestern University, Chicago, IL, 60611, USA
| | - Gary E Schiltz
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, 60208, USA
- Department of Pharmacology, Northwestern University, Chicago, IL, 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
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11
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Iyamu ID, Lv W, Malik N, Mishra RK, Schiltz GE. Discovery of a novel class of potent and selective tetrahydroindazole-based sigma-1 receptor ligands. Bioorg Med Chem 2019; 27:1824-1835. [PMID: 30904383 PMCID: PMC6548570 DOI: 10.1016/j.bmc.2019.03.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 03/14/2019] [Accepted: 03/16/2019] [Indexed: 11/20/2022]
Abstract
The sigma-1 and sigma-2 receptors have been shown to play important roles in CNS diseases, cancer, and other disorders. These findings suggest that targeting these proteins with small-molecule modulators may be of important therapeutic value. Here we report the development of a new class of tetrahydroindazoles that are highly potent and selective ligands for sigma-1. Molecular modeling was used to rationalize the observed structure-activity relationships and identify key interactions responsible for increased potency of the optimized compounds. Assays for solubility and microsomal stability showed this series possesses favorable characteristics and is amenable to further therapeutic development. The compounds described herein will be useful in the development of new chemical probes for sigma-1 and to aid in future work therapeutically targeting this protein.
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Affiliation(s)
- Iredia D Iyamu
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, United States
| | - Wei Lv
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, United States
| | - Neha Malik
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, United States
| | - Rama K Mishra
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, United States; Department of Pharmacology, Northwestern University, Chicago, IL 60611, United States
| | - Gary E Schiltz
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60208, United States; Department of Pharmacology, Northwestern University, Chicago, IL 60611, United States; Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States.
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12
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Vázquez-Rosa E, Watson MR, Sahn JJ, Hodges TR, Schroeder RE, Cintrón-Pérez CJ, Shin MK, Yin TC, Emery JL, Martin SF, Liebl DJ, Pieper AA. Neuroprotective Efficacy of a Sigma 2 Receptor/TMEM97 Modulator (DKR-1677) after Traumatic Brain Injury. ACS Chem Neurosci 2019; 10:1595-1602. [PMID: 30421909 DOI: 10.1021/acschemneuro.8b00543] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Compounds targeting the sigma 2 receptor, which we recently cloned and showed to be identical with transmembrane protein 97 (σ2R/TMEM97), are broadly applicable therapeutic agents currently in clinical trials for imaging in breast cancer and for treatment of Alzheimer's disease and schizophrenia. These promising applications coupled with our previous observation that the σ2R/TMEM97 modulator SAS-0132 has neuroprotective attributes and improves cognition in wild-type mice suggests that modulating σ2R/TMEM97 may also have therapeutic benefits in other neurodegenerative conditions such as traumatic brain injury (TBI). Herein, we report that DKR-1677, a novel derivative of SAS-0132 with increased affinity and selectivity for σ2R/Tmem97 ( Ki = 5.1 nM), is neuroprotective after blast-induced and controlled cortical impact (CCI) TBI in mice. Specifically, we discovered that treatment with DKR-1677 decreases axonal degeneration after blast-induced TBI and enhances survival of cortical neurons and oligodendrocytes after CCI injury. Furthermore, treatment with DKR-1677 preserves cognition in the Morris water maze after blast TBI. Our results support an increasingly broad role for σ2R/Tmem97 modulation in neuroprotection and suggest a new approach for treating patients suffering from TBI.
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Affiliation(s)
- Edwin Vázquez-Rosa
- Department of Psychiatry and Department of Free Radical, Radiation Biology Program, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
- Department of Psychiatry Case Western Reserve University, Geriatric Research Education and Clinical Centers, Harrington Discovery Institute, University Hospital, Case Medical Center, Louis Stokes Cleveland VAMC, Cleveland, Ohio 44106, United States
| | - Michael R. Watson
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida 33136, United States
| | - James J. Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Timothy R. Hodges
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Rachel E. Schroeder
- Department of Psychiatry and Department of Free Radical, Radiation Biology Program, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
| | - Coral J. Cintrón-Pérez
- Department of Psychiatry Case Western Reserve University, Geriatric Research Education and Clinical Centers, Harrington Discovery Institute, University Hospital, Case Medical Center, Louis Stokes Cleveland VAMC, Cleveland, Ohio 44106, United States
| | - Min-Kyoo Shin
- Department of Psychiatry Case Western Reserve University, Geriatric Research Education and Clinical Centers, Harrington Discovery Institute, University Hospital, Case Medical Center, Louis Stokes Cleveland VAMC, Cleveland, Ohio 44106, United States
| | - Terry C. Yin
- Department of Psychiatry and Department of Free Radical, Radiation Biology Program, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
| | - Josie L. Emery
- Department of Psychiatry and Department of Free Radical, Radiation Biology Program, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
| | - Stephen F. Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Daniel J. Liebl
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida 33136, United States
| | - Andrew A. Pieper
- Department of Psychiatry and Department of Free Radical, Radiation Biology Program, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, United States
- Department of Psychiatry Case Western Reserve University, Geriatric Research Education and Clinical Centers, Harrington Discovery Institute, University Hospital, Case Medical Center, Louis Stokes Cleveland VAMC, Cleveland, Ohio 44106, United States
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13
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Singh A, Mobin SM, Mathur P. Preparation of the Ru 3(CO) 8-pyridine-alcohol cluster and its use for the selective catalytic transformation of primary to secondary amines. Dalton Trans 2018; 47:14033-14040. [PMID: 30232491 DOI: 10.1039/c8dt02972e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of pyridine alcohol based ruthenium carbonyl clusters Ru3(hep)2(CO)8 (1), Ru3(hpp)2(CO)8 (2), and Ru3(bhmp-H)2(CO)8 (3) {hep-H = 2-(2-hydroxyethyl)pyridine, hpp-H = 2-(3-hydroxypropyl)pyridine and bhmp-H2 = 2,6-bis(hydroxymethyl)pyridine} has been carried out by the reaction of the corresponding pyridine-alcohol ligands with Ru3(CO)12. Clusters 1-3 have been characterized using elemental analysis, NMR, FT-IR, mass spectrometry and single-crystal X-ray structures. The clusters were explored for the selective catalytic transformation of primary amines into secondary amines using alcohols as the mono-alkylating agents via hydrogen transfer reactions. All three display efficient catalytic activity with 1 being the most effective.
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Affiliation(s)
- Ajeet Singh
- Discipline of Chemistry, Indian Institute of Technology Indore, Simrol, Khandwa Road, Indore 453552, India.
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14
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Small molecule modulators of σ2R/Tmem97 reduce alcohol withdrawal-induced behaviors. Neuropsychopharmacology 2018; 43:1867-1875. [PMID: 29728649 PMCID: PMC6046036 DOI: 10.1038/s41386-018-0067-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/09/2018] [Accepted: 04/05/2018] [Indexed: 12/29/2022]
Abstract
Repeated cycles of intoxication and withdrawal enhance the negative reinforcing properties of alcohol and lead to neuroadaptations that underlie withdrawal symptoms driving alcohol dependence. Pharmacotherapies that target these neuroadaptations may help break the cycle of dependence. The sigma-1 receptor (σ1R) subtype has attracted interest as a possible modulator of the rewarding and reinforcing effects of alcohol. However, whether the sigma-2 receptor, recently cloned and identified as transmembrane protein 97 (σ2R/TMEM97), plays a role in alcohol-related behaviors is currently unknown. Using a Caenorhabditis elegans model, we identified two novel, selective σ2R/Tmem97 modulators that reduce alcohol withdrawal behavior via an ortholog of σ2R/TMEM97. We then show that one of these compounds blunted withdrawal-induced excessive alcohol drinking in a well-established rodent model of alcohol dependence. These discoveries provide the first evidence that σ2R/TMEM97 is involved in alcohol withdrawal behaviors and that this receptor is a potential new target for treating alcohol use disorder.
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15
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Turnaturi R, Montenegro L, Marrazzo A, Parenti R, Pasquinucci L, Parenti C. Benzomorphan skeleton, a versatile scaffold for different targets: A comprehensive review. Eur J Med Chem 2018; 155:492-502. [PMID: 29908442 DOI: 10.1016/j.ejmech.2018.06.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/23/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022]
Abstract
Despite the fact that the benzomorphan skeleton has mainly been employed in medicinal chemistry for the development of opioid analgesics, it is a versatile structure. Its stereochemistry, as well as opportune modifications at the phenolic hydroxyl group and at the basic nitrogen, play a pivotal role addressing the benzomorphan-based compounds to a specific target. In this review, we describe the structure activity-relationships (SARs) of benzomorphan-based compounds acting at sigma 1 receptor (σ1R), sigma 2 receptor (σ2R), voltage-dependent sodium channel, N-Methyl-d-Aspartate (NMDA) receptor-channel complex and other targets. Collectively, the SARs data have highlighted that the benzomorphan nucleus could be regarded as a useful template for the synthesis of drug candidates for different targets.
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Affiliation(s)
- Rita Turnaturi
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy.
| | - Lucia Montenegro
- Department of Drug Sciences, Pharmaceutical Technology Section, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Agostino Marrazzo
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
| | - Rosalba Parenti
- Department of Biomedical and Biotechnological Sciences, Physiology Section, University of Catania, Catania, Italy
| | - Lorella Pasquinucci
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
| | - Carmela Parenti
- Department of Drug Sciences, Pharmacology Section, University of Catania, Viale A. Doria, 6, 95100, Catania, Italy
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16
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Mondal S, Hegarty E, Sahn JJ, Scott LL, Gökçe SK, Martin C, Ghorashian N, Satarasinghe PN, Iyer S, Sae-Lee W, Hodges TR, Pierce JT, Martin SF, Ben-Yakar A. High-Content Microfluidic Screening Platform Used To Identify σ2R/Tmem97 Binding Ligands that Reduce Age-Dependent Neurodegeneration in C. elegans SC_APP Model. ACS Chem Neurosci 2018; 9:1014-1026. [PMID: 29426225 DOI: 10.1021/acschemneuro.7b00428] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nematode Caenorhabditis elegans, with tractable genetics and a well-defined nervous system, provides a unique whole-animal model system to identify novel drug targets and therapies for neurodegenerative diseases. Large-scale drug or target screens in models that recapitulate the subtle age- and cell-specific aspects of neurodegenerative diseases are limited by a technological requirement for high-throughput analysis of neuronal morphology. Recently, we developed a single-copy model of amyloid precursor protein (SC_APP) induced neurodegeneration that exhibits progressive degeneration of select cholinergic neurons. Our previous work with this model suggests that small molecule ligands of the sigma 2 receptor (σ2R), which was recently cloned and identified as transmembrane protein 97 (TMEM97), are neuroprotective. To determine structure-activity relationships for unexplored chemical space in our σ2R/Tmem97 ligand collection, we developed an in vivo high-content screening (HCS) assay to identify potential drug leads. The HCS assay uses our recently developed large-scale microfluidic immobilization chip and automated imaging platform. We discovered norbenzomorphans that reduced neurodegeneration in our C. elegans model, including two compounds that demonstrated significant neuroprotective activity at multiple doses. These findings provide further evidence that σ2R/Tmem97-binding norbenzomorphans may represent a new drug class for treating neurodegenerative diseases.
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17
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Linkens K, Schmidt HR, Sahn JJ, Kruse AC, Martin SF. Investigating isoindoline, tetrahydroisoquinoline, and tetrahydrobenzazepine scaffolds for their sigma receptor binding properties. Eur J Med Chem 2018; 151:557-567. [DOI: 10.1016/j.ejmech.2018.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/13/2022]
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18
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Abstract
Diverse structural types of natural products and their mimics have served as targets of opportunity in our laboratory to inspire the discovery and development of new methods and strategies to assemble polyfunctional and polycyclic molecular architectures. Furthermore, our efforts toward identifying novel compounds having useful biological properties led to the creation of new targets, many of which posed synthetic challenges that required the invention of new methodology. In this Perspective, selected examples of how we have exploited a diverse range of natural products and their mimics to create, explore, and solve a variety of problems in chemistry and biology will be discussed. The journey was not without its twists and turns, but the unexpected often led to new revelations and insights. Indeed, in our recent excursion into applications of synthetic organic chemistry to neuroscience, avoiding the more-traveled paths was richly rewarding.
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Affiliation(s)
- Stephen F Martin
- Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States
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19
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Sahn JJ, Mejia GL, Ray PR, Martin SF, Price TJ. Sigma 2 Receptor/Tmem97 Agonists Produce Long Lasting Antineuropathic Pain Effects in Mice. ACS Chem Neurosci 2017; 8:1801-1811. [PMID: 28644012 PMCID: PMC5715471 DOI: 10.1021/acschemneuro.7b00200] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neuropathic pain is an important medical problem with few effective treatments. The sigma 1 receptor (σ1R) is known to be a potential target for neuropathic pain therapeutics, and antagonists for this receptor are effective in preclinical models and are currently in phase II clinical trials. Conversely, relatively little is known about σ2R, which has recently been identified as transmembrane protein 97 (Tmem97). We generated a series of σ1R and σ2R/Tmem97 agonists and antagonists and tested them for efficacy in the mouse spared nerve injury (SNI) model. In agreement with previous reports, we find that σ1R ligands given intrathecally (IT) produce relief of SNI-induced mechanical hypersensitivity. We also find that the putative σ2R/Tmem97 agonists DKR-1005, DKR-1051, and UKH-1114 (Ki ∼ 46 nM) lead to relief of SNI-induced mechanical hypersensitivity, peaking at 48 h after dosing when given IT. This effect is blocked by the putative σ2R/Tmem97 antagonist SAS-0132. Systemic administration of UKH-1114 (10 mg/kg) relieves SNI-induced mechanical hypersensitivity for 48 h with a peak magnitude of effect equivalent to 100 mg/kg gabapentin and without producing any motor impairment. Finally, we find that the TMEM97 gene is expressed in mouse and human dorsal root ganglion (DRG) including populations of neurons that are involved in pain; however, the gene is also likely expressed in non-neuronal cells that may contribute to the observed behavioral effects. Our results show robust antineuropathic pain effects of σ1R and σ2R/Tmem97 ligands, demonstrate that σ2R/Tmem97 is a novel neuropathic pain target, and identify UKH-1114 as a lead molecule for further development.
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MESH Headings
- Amines/pharmacology
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/pharmacology
- Animals
- Cyclohexanecarboxylic Acids/pharmacology
- Disease Models, Animal
- Gabapentin
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Humans
- Hyperalgesia/drug therapy
- Hyperalgesia/metabolism
- Male
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Molecular Structure
- Motor Activity/drug effects
- Neuralgia/drug therapy
- Neuralgia/metabolism
- RNA, Messenger/metabolism
- Receptors, sigma/agonists
- Receptors, sigma/antagonists & inhibitors
- Receptors, sigma/metabolism
- Touch
- gamma-Aminobutyric Acid/pharmacology
- Sigma-1 Receptor
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Affiliation(s)
- James J. Sahn
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Galo L. Mejia
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Pradipta R. Ray
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Stephen F. Martin
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Theodore J. Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
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20
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Yi B, Sahn JJ, Ardestani PM, Evans AK, Scott LL, Chan JZ, Iyer S, Crisp A, Zuniga G, Pierce JT, Martin SF, Shamloo M. Small molecule modulator of sigma 2 receptor is neuroprotective and reduces cognitive deficits and neuroinflammation in experimental models of Alzheimer's disease. J Neurochem 2017; 140:561-575. [PMID: 27926996 DOI: 10.1111/jnc.13917] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 12/29/2022]
Abstract
Accumulating evidence suggests that modulating the sigma 2 receptor (Sig2R) can provide beneficial effects for neurodegenerative diseases. Herein, we report the identification of a novel class of Sig2R ligands and their cellular and in vivo activity in experimental models of Alzheimer's disease (AD). We report that SAS-0132 and DKR-1051, selective ligands of Sig2R, modulate intracellular Ca2+ levels in human SK-N-SH neuroblastoma cells. The Sig2R ligands SAS-0132 and JVW-1009 are neuroprotective in a C. elegans model of amyloid precursor protein-mediated neurodegeneration. Since this neuroprotective effect is replicated by genetic knockdown and knockout of vem-1, the ortholog of progesterone receptor membrane component-1 (PGRMC1), these results suggest that Sig2R ligands modulate a PGRMC1-related pathway. Last, we demonstrate that SAS-0132 improves cognitive performance both in the Thy-1 hAPPLond/Swe+ transgenic mouse model of AD and in healthy wild-type mice. These results demonstrate that Sig2R is a promising therapeutic target for neurocognitive disorders including AD.
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Affiliation(s)
- Bitna Yi
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California, USA
| | - James J Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Pooneh Memar Ardestani
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California, USA
| | - Andrew K Evans
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California, USA
| | - Luisa L Scott
- Waggoner Center for Alcohol and Addiction Research, Institute of Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution and Department of Neuroscience, The University of Texas at Austin, Austin, Texas, USA
| | - Jessica Z Chan
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Sangeetha Iyer
- Waggoner Center for Alcohol and Addiction Research, Institute of Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution and Department of Neuroscience, The University of Texas at Austin, Austin, Texas, USA
| | - Ashley Crisp
- Waggoner Center for Alcohol and Addiction Research, Institute of Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution and Department of Neuroscience, The University of Texas at Austin, Austin, Texas, USA
| | - Gabriella Zuniga
- Waggoner Center for Alcohol and Addiction Research, Institute of Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution and Department of Neuroscience, The University of Texas at Austin, Austin, Texas, USA
| | - Jonathan T Pierce
- Waggoner Center for Alcohol and Addiction Research, Institute of Neuroscience, Center for Learning and Memory, Center for Brain, Behavior and Evolution and Department of Neuroscience, The University of Texas at Austin, Austin, Texas, USA
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Mehrdad Shamloo
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, California, USA
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21
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Alon A, Schmidt HR, Wood MD, Sahn JJ, Martin SF, Kruse AC. Identification of the gene that codes for the σ 2 receptor. Proc Natl Acad Sci U S A 2017; 114:7160-7165. [PMID: 28559337 PMCID: PMC5502638 DOI: 10.1073/pnas.1705154114] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The σ2 receptor is an enigmatic protein that has attracted significant attention because of its involvement in diseases as diverse as cancer and neurological disorders. Unlike virtually all other receptors of medical interest, it has eluded molecular cloning since its discovery, and the gene that codes for the receptor remains unknown, precluding the use of modern biological methods to study its function. Using a chemical biology approach, we purified the σ2 receptor from tissue, revealing its identity as TMEM97, an endoplasmic reticulum-resident transmembrane protein that regulates the sterol transporter NPC1. We show that TMEM97 possesses the full suite of molecular properties that define the σ2 receptor, and we identify Asp29 and Asp56 as essential for ligand recognition. Cloning the σ2 receptor resolves a longstanding mystery and will enable therapeutic targeting of this potential drug target.
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Affiliation(s)
- Assaf Alon
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Hayden R Schmidt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Michael D Wood
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - James J Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Stephen F Martin
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115;
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22
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Sahn JJ, Hodges TR, Chan JZ, Martin SF. Norbenzomorphan Scaffold: Chemical Tool for Modulating Sigma Receptor-Subtype Selectivity. ACS Med Chem Lett 2017; 8:455-460. [PMID: 28435536 DOI: 10.1021/acsmedchemlett.7b00066] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/21/2017] [Indexed: 01/11/2023] Open
Abstract
Some norbenzomorphans exhibit high affinity for sigma 1 and sigma 2 receptors, and varying the position of substituents on the aromatic ring of this scaffold has a significant effect on subtype selectivity. In particular, compounds bearing several different substituents at C7 of the norbenzomorphan ring system exhibit a general preference for the sigma 1 receptor, whereas the corresponding C8-substituted analogues preferentially bind at the sigma 2 receptor. These findings suggest that the norbenzomorphan scaffold may be a unique chemical template that can be easily tuned to prepare small molecules for use as tool compounds to study the specific biological effects arising from preferential binding at either sigma receptor subtype. In the absence of structural characterization data for the sigma 2 receptor, such compounds will be useful toward refining the pharmacophore model of its binding site.
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Affiliation(s)
- James J. Sahn
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Timothy R. Hodges
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jessica Z. Chan
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Stephen F. Martin
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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