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Lu S, Haskali MB, Ruley KM, Dreyfus NJF, DuBois SL, Paul S, Liow JS, Morse CL, Kowalski A, Gladding RL, Gilmore J, Mogg AJ, Morin SM, Lindsay-Scott PJ, Ruble JC, Kant NA, Shcherbinin S, Barth VN, Johnson MP, Cuadrado M, Jambrina E, Mannes AJ, Nuthall HN, Zoghbi SS, Jesudason CD, Innis RB, Pike VW. PET ligands [ 18F]LSN3316612 and [ 11C]LSN3316612 quantify O-linked-β- N-acetyl-glucosamine hydrolase in the brain. Sci Transl Med 2020; 12:eaau2939. [PMID: 32404505 PMCID: PMC8494060 DOI: 10.1126/scitranslmed.aau2939] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 03/11/2020] [Indexed: 12/22/2023]
Abstract
We aimed to develop effective radioligands for quantifying brain O-linked-β-N-acetyl-glucosamine (O-GlcNAc) hydrolase (OGA) using positron emission tomography in living subjects as tools for evaluating drug target engagement. Posttranslational modifications of tau, a biomarker of Alzheimer's disease, by O-GlcNAc through the enzyme pair OGA and O-GlcNAc transferase (OGT) are inversely related to the amounts of its insoluble hyperphosphorylated form. Increase in tau O-GlcNAcylation by OGA inhibition is believed to reduce tau aggregation. LSN3316612, a highly selective and potent OGA ligand [half-maximal inhibitory concentration (IC50) = 1.9 nM], emerged as a lead ligand after in silico analysis and in vitro evaluations. [3H]LSN3316612 imaged and quantified OGA in postmortem brains of rat, monkey, and human. The presence of fluorine and carbonyl functionality in LSN3316612 enabled labeling with positron-emitting fluorine-18 or carbon-11. Both [18F]LSN3316612 and [11C]LSN3316612 bound reversibly to OGA in vivo, and such binding was blocked by pharmacological doses of thiamet G, an OGA inhibitor of different chemotype, in monkeys. [18F]LSN3316612 entered healthy human brain avidly (~4 SUV) without radiodefluorination or adverse effect from other radiometabolites, as evidenced by stable brain total volume of distribution (VT) values by 110 min of scanning. Overall, [18F]LSN3316612 is preferred over [11C]LSN3316612 for future human studies, whereas either may be an effective positron emission tomography radioligand for quantifying brain OGA in rodent and monkey.
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Affiliation(s)
- Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Mohammad B Haskali
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | | | | | | | - Soumen Paul
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Aneta Kowalski
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | | | | | | | | | | | | | | | | | | | - Maria Cuadrado
- Lilly, S. A. Avenida de la Industria 30, 28108 Alcobendas, Madrid, Spain
| | - Enrique Jambrina
- Lilly, S. A. Avenida de la Industria 30, 28108 Alcobendas, Madrid, Spain
| | - Andrew J Mannes
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892-1510, USA
| | | | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | | | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA.
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Broad LM, Sanger HE, Mogg AJ, Colvin EM, Zwart R, Evans DA, Pasqui F, Sher E, Wishart GN, Barth VN, Felder CC, Goldsmith PJ. Identification and pharmacological profile of SPP1, a potent, functionally selective and brain penetrant agonist at muscarinic M 1 receptors. Br J Pharmacol 2019; 176:110-126. [PMID: 30276808 PMCID: PMC6284335 DOI: 10.1111/bph.14510] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 09/14/2018] [Accepted: 09/18/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE We aimed to identify and develop novel, selective muscarinic M1 receptor agonists as potential therapeutic agents for the symptomatic treatment of Alzheimer's disease. EXPERIMENTAL APPROACH We developed and utilized a novel M1 receptor occupancy assay to drive a structure activity relationship in a relevant brain region while simultaneously tracking drug levels in plasma and brain to optimize for central penetration. Functional activity was tracked in relevant native in vitro assays allowing translational (rat-human) benchmarking of structure-activity relationship molecules to clinical comparators. KEY RESULTS Using this paradigm, we identified a series of M1 receptor selective molecules displaying desirable in vitro and in vivo properties and optimized key features, such as central penetration while maintaining selectivity and a partial agonist profile. From these compounds, we selected spiropiperidine 1 (SPP1). In vitro, SPP1 is a potent, partial agonist of cortical and hippocampal M1 receptors with activity conserved across species. SPP1 displays high functional selectivity for M1 receptors over native M2 and M3 receptor anti-targets and over a panel of other targets. Assessment of central target engagement by receptor occupancy reveals SPP1 significantly and dose-dependently occupies rodent cortical M1 receptors. CONCLUSIONS AND IMPLICATIONS We report the discovery of SPP1, a novel, functionally selective, brain penetrant partial orthosteric agonist at M1 receptors, identified by a novel receptor occupancy assay. SPP1 is amenable to in vitro and in vivo study and provides a valuable research tool to further probe the role of M1 receptors in physiology and disease.
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Affiliation(s)
- Lisa M Broad
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | - Helen E Sanger
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | - Adrian J Mogg
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | - Ellen M Colvin
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | - Ruud Zwart
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | - David A Evans
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | | | - Emanuele Sher
- Eli Lilly and Company, Lilly Research CentreWindleshamSurreyUK
| | | | - Vanessa N Barth
- Eli Lilly and Company, Lilly Corporate CenterIndianapolisINUSA
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Paul S, Haskali MB, Liow JS, Zoghbi SS, Barth VN, Kolodrubetz MC, Bond MR, Morse CL, Gladding RL, Frankland MP, Kant N, Slieker L, Shcherbinin S, Nuthall HN, Zanotti-Fregonara P, Hanover JA, Jesudason C, Pike VW, Innis RB. Evaluation of a PET Radioligand to Image O-GlcNAcase in Brain and Periphery of Rhesus Monkey and Knock-Out Mouse. J Nucl Med 2018; 60:129-134. [PMID: 30213846 DOI: 10.2967/jnumed.118.213231] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/09/2018] [Indexed: 02/07/2023] Open
Abstract
Accumulation of hyperphosphorylated tau, a microtubule-associated protein, plays an important role in the progression of Alzheimer disease. Animal studies suggest that one strategy for treating Alzheimer disease and related tauopathies may be inhibition of O-GlcNAcase (OGA), which may subsequently decrease pathologic tau phosphorylation. Here, we report the pharmacokinetics of a novel PET radioligand, 18F-LSN3316612, which binds with high affinity and selectivity to OGA. Methods: PET imaging was performed on rhesus monkeys at baseline and after administration of either thiamet-G, a potent OGA inhibitor, or nonradioactive LSN3316612. The density of the enzyme was calculated as distribution volume using a 2-tissue-compartment model and serial concentrations of parent radioligand in arterial plasma. The radiation burden for future studies was based on whole-body imaging of monkeys. Oga ∆Br, a mouse brain-specific knockout of Oga, was also scanned to assess the specificity of the radioligand for its target enzyme. Results: Uptake of radioactivity in monkey brain was high (∼5 SUV) and followed by slow washout. The highest uptake was in the amygdala, followed by striatum and hippocampus. Pretreatment with thiamet-G or nonradioactive LSN3316612 reduced brain uptake to a low and uniform concentration in all regions, corresponding to an approximately 90% decrease in distribution volume. Whole-body imaging of rhesus monkeys showed high uptake in kidney, spleen, liver, and testes. In Oga ∆Br mice, brain uptake of 18F-LSN3316612 was reduced by 82% compared with control mice. Peripheral organs were unaffected in Oga ∆Br mice, consistent with loss of OGA expression exclusively in the brain. The effective dose of 18F-LSN3316612 in humans was calculated to be 22 μSv/MBq, which is typical for 18F-labeled radioligands. Conclusion: These results show that 18F-LSN3316612 is an excellent radioligand for imaging and quantifying OGA in rhesus monkeys and mice. On the basis of these data, 18F-LSN3316612 merits evaluation in humans.
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Affiliation(s)
- Soumen Paul
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Mohammad B Haskali
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland.,Peter MacCallum Cancer Centre, Melbourne, Australia
| | - Jeih-San Liow
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Sami S Zoghbi
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | | | | | - Michelle R Bond
- LCMB, NIDDK, National Institutes of Health, Bethesda, Maryland
| | - Cheryl L Morse
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Robert L Gladding
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Michael P Frankland
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Nancy Kant
- Eli Lilly and Company, Indianapolis, Indiana
| | | | | | | | | | - John A Hanover
- LCMB, NIDDK, National Institutes of Health, Bethesda, Maryland
| | | | - Victor W Pike
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Robert B Innis
- Molecular Imaging Branch, NIMH, National Institutes of Health, Bethesda, Maryland
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Mogg AJ, Eessalu T, Johnson M, Wright R, Sanger HE, Xiao H, Crabtree MG, Smith A, Colvin EM, Schober D, Gehlert D, Jesudason C, Goldsmith PJ, Johnson MP, Felder CC, Barth VN, Broad LM. In Vitro Pharmacological Characterization and In Vivo Validation of LSN3172176 a Novel M1 Selective Muscarinic Receptor Agonist Tracer Molecule for Positron Emission Tomography. J Pharmacol Exp Ther 2018; 365:602-613. [PMID: 29643252 DOI: 10.1124/jpet.117.246454] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 04/05/2018] [Indexed: 12/20/2022] Open
Abstract
In the search for improved symptomatic treatment options for neurodegenerative and neuropsychiatric diseases, muscarinic acetylcholine M1 receptors (M1 mAChRs) have received significant attention. Drug development efforts have identified a number of novel ligands, some of which have advanced to the clinic. However, a significant issue for progressing these therapeutics is the lack of robust, translatable, and validated biomarkers. One valuable approach to assessing target engagement is to use positron emission tomography (PET) tracers. In this study we describe the pharmacological characterization of a selective M1 agonist amenable for in vivo tracer studies. We used a novel direct binding assay to identify nonradiolabeled ligands, including LSN3172176, with the favorable characteristics required for a PET tracer. In vitro functional and radioligand binding experiments revealed that LSN3172176 was a potent partial agonist (EC50 2.4-7.0 nM, Emax 43%-73%), displaying binding selectivity for M1 mAChRs (Kd = 1.5 nM) that was conserved across species (native tissue Kd = 1.02, 2.66, 8, and 1.03 at mouse, rat, monkey, and human, respectively). Overall selectivity of LSN3172176 appeared to be a product of potency and stabilization of the high-affinity state of the M1 receptor, relative to other mAChR subtypes (M1 > M2, M4, M5 > M3). In vivo, use of wild-type and mAChR knockout mice further supported the M1-preferring selectivity profile of LSN3172176 for the M1 receptor (78% reduction in cortical occupancy in M1 KO mice). These findings support the development of LSN3172176 as a potential PET tracer for assessment of M1 mAChR target engagement in the clinic and to further elucidate the function of M1 mAChRs in health and disease.
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Affiliation(s)
- Adrian J Mogg
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Thomas Eessalu
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Megan Johnson
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Rebecca Wright
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Helen E Sanger
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Hongling Xiao
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Michael G Crabtree
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Alex Smith
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Ellen M Colvin
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Douglas Schober
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Donald Gehlert
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Cynthia Jesudason
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Paul J Goldsmith
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Michael P Johnson
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Christian C Felder
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Vanessa N Barth
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
| | - Lisa M Broad
- Eli Lilly & Co. Ltd., Lilly Research Centre, Windlesham, Surrey, United Kingdom (A.J.M., H.E.S., M.G.C., A.S., E.M.C., P.J.G., L.M.B.) and Eli Lilly & Co. Ltd., Lilly Corporate Center, Indianapolis, Indiana (T.E., M.J., R.W., H.X., D.S., D.G., C.J., M.P.J., C.C.F., V.N.B.)
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5
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Albrecht DS, Normandin MD, Shcherbinin S, Wooten DW, Schwarz AJ, Zürcher NR, Barth VN, Guehl NJ, Akeju O, Atassi N, Veronese M, Turkheimer F, Hooker JM, Loggia ML. Pseudoreference Regions for Glial Imaging with 11C-PBR28: Investigation in 2 Clinical Cohorts. J Nucl Med 2018; 59:107-114. [PMID: 28818984 PMCID: PMC5750517 DOI: 10.2967/jnumed.116.178335] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 07/17/2017] [Indexed: 12/12/2022] Open
Abstract
The translocator protein (TSPO) is a commonly used imaging target to investigate neuroinflammation. Although TSPO imaging demonstrates great promise, its signal exhibits substantial interindividual variability, which needs to be accounted for to uncover group effects that are truly reflective of neuroimmune activation. Recent evidence suggests that relative metrics computed using pseudoreference approaches can minimize within-group variability and increase sensitivity to detect physiologically meaningful group differences. Here, we evaluated various ratio approaches for TSPO imaging and compared them with standard kinetic modeling techniques, analyzing 2 different disease cohorts. Patients with chronic low back pain (cLBP) or amyotrophic lateral sclerosis (ALS) and matching healthy controls received 11C-PBR28 PET scans. The occipital cortex, cerebellum and whole brain were first evaluated as candidate pseudoreference regions by testing for the absence of group differences in SUV and distribution volume (VT) estimated with an arterial input function. The SUV from target regions (cLBP study, thalamus; ALS study, precentral gyrus) was normalized with the SUV from candidate pseudoreference regions (i.e., occipital cortex, cerebellum, and whole brain) to obtain SUVRoccip, SUVRcereb, and SUVRWB The sensitivity to detect group differences in target regions was compared using various SUVR approaches, as well as distribution volume ratio (DVR) estimated with (blDVR) or without arterial input function (refDVR), and VT Additional voxelwise SUVR group analyses were performed. We observed no significant group differences in pseudoreference VT or SUV, excepting whole-brain VT, which was higher in cLBP patients than controls. Target VT elevations in patients (P = 0.028 and 0.051 in cLBP and ALS, respectively) were similarly detected by SUVRoccip and SUVRWB, and by refDVR and blDVR (less reliably by SUVRcereb). In voxelwise analyses, SUVRoccip, but not SUVRcereb, identified regional group differences initially observed with SUVRWB, and in additional areas suspected to be affected in the pathology examined. All ratio metrics were highly cross-correlated, but generally were not associated with VT. Although important caveats need to be considered when using relative metrics, ratio analyses appear to be similarly sensitive to detect pathology-related group differences in 11C-PBR28 signal as classic kinetic modeling techniques. The occipital cortex may be a suitable pseudoreference region, at least for the populations evaluated, pending further validation in larger cohorts.
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Affiliation(s)
- Daniel S Albrecht
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | - Marc D Normandin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | | | - Dustin W Wooten
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | | | - Nicole R Zürcher
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | | | - Nicolas J Guehl
- Gordon Center for Medical Imaging, NMMI, Radiology Department, Massachusetts General Hospital & Harvard Medical School, Boston, Massachusetts
| | - Oluwaseun Akeju
- Department of Anesthesiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Nazem Atassi
- Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, King's College London, London, United Kingdom
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Marco L Loggia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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6
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Witkin JM, Rorick-Kehn LM, Benvenga MJ, Adams BL, Gleason SD, Knitowski KM, Li X, Chaney S, Falcone JF, Smith JW, Foss J, Lloyd K, Catlow JT, McKinzie DL, Svensson KA, Barth VN, Toledo MA, Diaz N, Lafuente C, Jiménez A, Benito A, Pedregal C, Martínez-Grau MA, Post A, Ansonoff MA, Pintar JE, Statnick MA. Preclinical findings predicting efficacy and side-effect profile of LY2940094, an antagonist of nociceptin receptors. Pharmacol Res Perspect 2016; 4:e00275. [PMID: 28097008 PMCID: PMC5226289 DOI: 10.1002/prp2.275] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 12/28/2022] Open
Abstract
Nociceptin/Orphanin FQ (N/OFQ) is a 17 amino acid peptide whose receptor is designated ORL1 or nociceptin receptor (NOP). We utilized a potent, selective, and orally bioavailable antagonist with documented engagement with NOP receptors in vivo to assess antidepressant‐ and anxiolytic‐related pharmacological effects of NOP receptor blockade along with measures of cognitive and motor impingement. LY2940094 ([2‐[4‐[(2‐chloro‐4,4‐difluoro‐spiro[5H‐thieno[2,3‐c]pyran‐7,4′‐piperidine]‐1′‐yl)methyl]‐3‐methyl‐pyrazol‐1‐yl]‐3‐pyridyl]methanol) displayed antidepressant‐like behavioral effects in the forced‐swim test in mice, an effect absent in NOP−/− mice. LY2940094 also augmented the behavioral effect of fluoxetine without changing target occupancies (NOP and serotonin reuptake transporter [SERT]). LY2940094 did not have effects under a differential‐reinforcement of low rate schedule. Although anxiolytic‐like effects were not observed in some animal models (conditioned suppression, 4‐plate test, novelty‐suppressed feeding), LY2940094 had effects like that of anxiolytic drugs in three assays: fear‐conditioned freezing in mice, stress‐induced increases in cerebellar cGMP in mice, and stress‐induced hyperthermia in rats. These are the first reports of anxiolytic‐like activity with a systemically viable NOP receptor antagonist. LY2940094 did not disrupt performance in either a 5‐choice serial reaction time or delayed matching‐to‐position assay. LY2940094 was also not an activator or suppressor of locomotion in rodents nor did it induce failures of rotarod performance. These data suggest that LY2940094 has unique antidepressant‐ and anxiolytic‐related pharmacological effects in rodents. Clinical proof of concept data on this molecule in depressed patients have been reported elsewhere.
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Affiliation(s)
- Jeffrey M Witkin
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | | | - Mark J Benvenga
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Benjamin L Adams
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Scott D Gleason
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Karen M Knitowski
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Xia Li
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Steven Chaney
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Julie F Falcone
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Janice W Smith
- Lilly Research Laboratories Eli Lilly and Company Windlesham Surrey United Kingdom
| | - Julie Foss
- Lilly Research Laboratories Eli Lilly and Company Windlesham Surrey United Kingdom
| | - Kirsti Lloyd
- Lilly Research Laboratories Eli Lilly and Company Windlesham Surrey United Kingdom
| | - John T Catlow
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - David L McKinzie
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Kjell A Svensson
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Vanessa N Barth
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana
| | - Miguel A Toledo
- Lilly Research Laboratories Eli Lilly and Company Indianapolis Indiana; Lilly Research Laboratories Eli Lilly and Company Alcobendas Madrid Spain
| | - Nuria Diaz
- Lilly Research Laboratories Eli Lilly and Company Alcobendas Madrid Spain
| | - Celia Lafuente
- Lilly Research Laboratories Eli Lilly and Company Alcobendas Madrid Spain
| | - Alma Jiménez
- Lilly Research Laboratories Eli Lilly and Company Alcobendas Madrid Spain
| | - Alfonso Benito
- Lilly Research Laboratories Eli Lilly and Company Alcobendas Madrid Spain
| | | | | | - Anke Post
- Lilly Research Laboratories Eli Lilly and Company Windlesham Surrey United Kingdom
| | - Michael A Ansonoff
- Lilly Research Laboratories Eli Lilly and Company Rutgers-Robert Wood Johnson Medical School New Brunswick New Jersey
| | - John E Pintar
- Lilly Research Laboratories Eli Lilly and Company Rutgers-Robert Wood Johnson Medical School New Brunswick New Jersey
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7
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Gardinier KM, Gernert DL, Porter WJ, Reel JK, Ornstein PL, Spinazze P, Stevens FC, Hahn P, Hollinshead SP, Mayhugh D, Schkeryantz J, Khilevich A, De Frutos O, Gleason SD, Kato AS, Luffer-Atlas D, Desai PV, Swanson S, Burris KD, Ding C, Heinz BA, Need AB, Barth VN, Stephenson GA, Diseroad BA, Woods TA, Yu H, Bredt D, Witkin JM. Discovery of the First α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor Antagonist Dependent upon Transmembrane AMPA Receptor Regulatory Protein (TARP) γ-8. J Med Chem 2016; 59:4753-68. [PMID: 27067148 DOI: 10.1021/acs.jmedchem.6b00125] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transmembrane AMPA receptor regulatory proteins (TARPs) are a family of scaffolding proteins that regulate AMPA receptor trafficking and function. TARP γ-8 is one member of this family and is highly expressed within the hippocampus relative to the cerebellum. A selective TARP γ-8-dependent AMPA receptor antagonist (TDAA) is an innovative approach to modulate AMPA receptors in specific brain regions to potentially increase the therapeutic index relative to known non-TARP-dependent AMPA antagonists. We describe here, for the first time, the discovery of a noncompetitive AMPA receptor antagonist that is dependent on the presence of TARP γ-8. Three major iteration cycles were employed to improve upon potency, CYP1A2-dependent challenges, and in vivo clearance. An optimized molecule, compound (-)-25 (LY3130481), was fully protective against pentylenetetrazole-induced convulsions in rats without the motor impairment associated with non-TARP-dependent AMPA receptor antagonists. Compound (-)-25 could be utilized to provide proof of concept for antiepileptic efficacy with reduced motor side effects in patients.
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Affiliation(s)
- Kevin M Gardinier
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Douglas L Gernert
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Warren J Porter
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Jon K Reel
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Paul L Ornstein
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Patrick Spinazze
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - F Craig Stevens
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Patric Hahn
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Sean P Hollinshead
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Daniel Mayhugh
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Jeff Schkeryantz
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Albert Khilevich
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Oscar De Frutos
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Scott D Gleason
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Akihiko S Kato
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Debra Luffer-Atlas
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Prashant V Desai
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Steven Swanson
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Kevin D Burris
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Chunjin Ding
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Beverly A Heinz
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Anne B Need
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Vanessa N Barth
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Gregory A Stephenson
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Benjamin A Diseroad
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Tim A Woods
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Hong Yu
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - David Bredt
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
| | - Jeffrey M Witkin
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana 46285 United States
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8
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Bakker G, Vingerhoets WA, Wieringen JV, de Bruin K, Eersels J, de Jong J, Chahid Y, Rutten BP, DuBois S, Watson M, Mogg AJ, Xiao H, Crabtree M, Collier DA, Felder CC, Barth VN, Broad LM, Bloemen OJ, van Amelsvoort TA, Booij J. 123I-Iododexetimide Preferentially Binds to the Muscarinic Receptor Subtype M1 In Vivo. J Nucl Med 2015; 56:317-22. [DOI: 10.2967/jnumed.114.147488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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9
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Toledo MA, Pedregal C, Lafuente C, Diaz N, Martinez-Grau MA, Jiménez A, Benito A, Torrado A, Mateos C, Joshi EM, Kahl SD, Rash KS, Mudra DR, Barth VN, Shaw DB, McKinzie D, Witkin JM, Statnick MA. Discovery of a novel series of orally active nociceptin/orphanin FQ (NOP) receptor antagonists based on a dihydrospiro(piperidine-4,7'-thieno[2,3-c]pyran) scaffold. J Med Chem 2014; 57:3418-29. [PMID: 24678969 DOI: 10.1021/jm500117r] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Nociceptin/OFQ (N/OFQ) is a 17 amino acid peptide that is the endogenous ligand for the ORL1/NOP receptor. Nociceptin appears to regulate a host of physiological functions such as biological reactions to stress, anxiety, mood, and drug abuse, in addition to feeding behaviors. To develop tools to study the function of nociceptin and NOP receptor, our research effort sought to identify orally available NOP antagonists. Our effort led to the discovery of a novel chemical series based on the dihydrospiro(piperidine-4,7'-thieno[2,3-c]pyran) scaffold. Herein we show that dihydrospiro(piperidine-4,7'-thieno[2,3-c]pyran)-derived compounds are potent NOP antagonists with high selectivity versus classical opioid receptors (μ, δ, and κ). Moreover, these compounds exhibit sufficient bioavailability to produce a high level of NOP receptor occupancy in the brain following oral administration in rats.
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Affiliation(s)
- Miguel A Toledo
- Centro de Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas, Madrid, Spain
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Lohith TG, Zoghbi SS, Morse CL, Araneta MDF, Barth VN, Goebl NA, Tauscher JT, Pike VW, Innis RB, Fujita M. Retest imaging of [11C]NOP-1A binding to nociceptin/orphanin FQ peptide (NOP) receptors in the brain of healthy humans. Neuroimage 2014; 87:89-95. [PMID: 24225488 PMCID: PMC3928240 DOI: 10.1016/j.neuroimage.2013.10.068] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 09/26/2013] [Accepted: 10/31/2013] [Indexed: 11/27/2022] Open
Abstract
[(11)C]NOP-1A is a novel high-affinity PET ligand for imaging nociceptin/orphanin FQ peptide (NOP) receptors. Here, we report reproducibility and reliability measures of binding parameter estimates for [(11)C]NOP-1A binding in the brain of healthy humans. After intravenous injection of [(11)C]NOP-1A, PET scans were conducted twice on eleven healthy volunteers on the same (10/11 subjects) or different (1/11 subjects) days. Subjects underwent serial sampling of radial arterial blood to measure parent radioligand concentrations. Distribution volume (VT; a measure of receptor density) was determined by compartmental (one- and two-tissue) modeling in large regions and by simpler regression methods (graphical Logan and bilinear MA1) in both large regions and voxel data. Retest variability and intraclass correlation coefficient (ICC) of VT were determined as measures of reproducibility and reliability respectively. Regional [(11)C]NOP-1A uptake in the brain was high, with a peak radioactivity concentration of 4-7 SUV (standardized uptake value) and a rank order of putamen>cingulate cortex>cerebellum. Brain time-activity curves fitted well in 10 of 11 subjects by unconstrained two-tissue compartmental model. The retest variability of VT was moderately good across brain regions except cerebellum, and was similar across different modeling methods, averaging 12% for large regions and 14% for voxel-based methods. The retest reliability of VT was also moderately good in most brain regions, except thalamus and cerebellum, and was similar across different modeling methods averaging 0.46 for large regions and 0.48 for voxels having gray matter probability >20%. The lowest retest variability and highest retest reliability of VT were achieved by compartmental modeling for large regions, and by the parametric Logan method for voxel-based methods. Moderately good reproducibility and reliability measures of VT for [(11)C]NOP-1A make it a useful PET ligand for comparing NOP receptor binding between different subject groups or under different conditions in the same subject.
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Affiliation(s)
- Talakad G Lohith
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Maria D Ferraris Araneta
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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11
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Wang C, Eessalu TE, Barth VN, Mitch CH, Wagner FF, Hong Y, Neelamegam R, Schroeder FA, Holson EB, Haggarty SJ, Hooker JM. Design, synthesis, and evaluation of hydroxamic acid-based molecular probes for in vivo imaging of histone deacetylase (HDAC) in brain. Am J Nucl Med Mol Imaging 2013; 4:29-38. [PMID: 24380043 PMCID: PMC3867727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/01/2013] [Indexed: 06/03/2023]
Abstract
Hydroxamic acid-based histone deacetylase inhibitors (HDACis) are a class of molecules with therapeutic potential currently reflected in the use of suberoylanilide hydroxamic acid (SAHA; Vorinostat) to treat cutaneous T-cell lymphomas (CTCL). HDACis may have utility beyond cancer therapy, as preclinical studies have ascribed HDAC inhibition as beneficial in areas such as heart disease, diabetes, depression, neurodegeneration, and other disorders of the central nervous system (CNS). However, little is known about the pharmacokinetics (PK) of hydroxamates, particularly with respect to CNS-penetration, distribution, and retention. To explore the rodent and non-human primate (NHP) brain permeability of hydroxamic acid-based HDAC inhibitors using positron emission tomography (PET), we modified the structures of belinostat (PXD101) and panobinostat (LBH-589) to incorporate carbon-11. We also labeled PCI 34051 through carbon isotope substitution. After characterizing the in vitro affinity and efficacy of these compounds across nine recombinant HDAC isoforms spanning Class I and Class II family members, we determined the brain uptake of each inhibitor. Each labeled compound has low uptake in brain tissue when administered intravenously to rodents and NHPs. In rodent studies, we observed that brain accumulation of the radiotracers were unaffected by the pre-administration of unlabeled inhibitors. Knowing that CNS-penetration may be desirable for both imaging applications and therapy, we explored whether a liquid chromatography, tandem mass spectrometry (LC-MS-MS) method to predict brain penetrance would be an appropriate method to pre-screen compounds (hydroxamic acid-based HDACi) prior to PET radiolabeling. LC-MS-MS data were indeed useful in identifying additional lead molecules to explore as PET imaging agents to visualize HDAC enzymes in vivo. However, HDACi brain penetrance predicted by LC-MS-MS did not strongly correlate with PET imaging results. This underscores the importance of in vivo PET imaging tools in characterizing putative CNS drug lead compounds and the continued need to discover effect PET tracers for neuroepigenetic imaging.
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Affiliation(s)
- Changning Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA 02129, USA
| | | | | | | | - Florence F Wagner
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT7 Cambridge Center, Cambridge, MA 02142, USA
| | - Yijia Hong
- Department of Molecular and Cell Biology, University of CaliforniaBerkeley, CA 94720, USA
| | - Ramesh Neelamegam
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA 02129, USA
| | - Frederick A Schroeder
- Chemical Neurobiology Laboratory, Departments of Neurology and Psychiatry, Center for Human Genetic Research, Massachusetts General Hospital185 Cambridge Street, Boston, MA 02114, USA
| | - Edward B Holson
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT7 Cambridge Center, Cambridge, MA 02142, USA
| | - Stephen J Haggarty
- Chemical Neurobiology Laboratory, Departments of Neurology and Psychiatry, Center for Human Genetic Research, Massachusetts General Hospital185 Cambridge Street, Boston, MA 02114, USA
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA 02129, USA
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12
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Zanotti-Fregonara P, Barth VN, Zoghbi SS, Liow JS, Nisenbaum E, Siuda E, Gladding RL, Rallis-Frutos D, Morse C, Tauscher J, Pike VW, Innis RB. 11C-LY2428703, a positron emission tomographic radioligand for the metabotropic glutamate receptor 1, is unsuitable for imaging in monkey and human brains. EJNMMI Res 2013; 3:47. [PMID: 23758896 PMCID: PMC3683333 DOI: 10.1186/2191-219x-3-47] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/31/2013] [Indexed: 02/03/2023] Open
Abstract
Background A recent study from our laboratory demonstrated that 11C-LY2428703, a new positron emission tomographic radioligand for metabotropic glutamate receptor 1 (mGluR1), has promising in vitro properties and excellent in vivo performance for imaging rat brain. The present study evaluated 11C-LY2428703 for imaging mGluR1 in monkey and human brains. Methods Rhesus monkeys were imaged at baseline and after administration of an mGluR1 blocking agent to calculate nonspecific binding, as well as after the administration of permeability glycoprotein (P-gp) and breast cancer resistance protein (BCRP) blockers to assess whether 11C-LY2428703 is a substrate for efflux transporters at the blood–brain barrier. Human imaging was performed at baseline in three healthy volunteers, and arterial input function was measured. Results Overall brain uptake was low in monkeys, though slightly higher in the cerebellum, where mGluR1s are concentrated. However, the uptake was not clearly displaceable in the scans after mGluR1 blockade. Brain penetration of the ligand did not increase after P-gp and BCRP blockade. Brain uptake was similarly low in all human subjects (mean VT with a two-tissue compartment model, 0.093 ± 0.012 mL/cm3) and for all regions, including the cerebellum. Conclusions Despite promising in vitro and in vivo results in rodents, 11C-LY2428703 was unsuitable for imaging mGluR1s in monkey or human brain because of low brain uptake, which was likely caused by high binding to plasma proteins.
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Affiliation(s)
- Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, 10 Center Drive, Bethesda, MD 20892, USA.
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13
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Zanotti-Fregonara P, Barth VN, Liow JS, Zoghbi SS, Clark DT, Rhoads E, Siuda E, Heinz BA, Nisenbaum E, Dressman B, Joshi E, Luffer-Atlas D, Fisher MJ, Masters JJ, Goebl N, Kuklish SL, Morse C, Tauscher J, Pike VW, Innis RB. Evaluation in vitro and in animals of a new 11C-labeled PET radioligand for metabotropic glutamate receptors 1 in brain. Eur J Nucl Med Mol Imaging 2012; 40:245-53. [PMID: 23135321 DOI: 10.1007/s00259-012-2269-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE Two allosteric modulators of the group I metabotropic glutamate receptors (mGluR1 and mGluR5) were evaluated as positron emission tomography (PET) radioligands for mGluR1. METHODS LY2428703, a full mGluR1 antagonist (IC(50) 8.9 nM) and partial mGluR5 antagonist (IC(50) 118 nM), and LSN2606428, a full mGluR1 and mGluR5 antagonist (IC(50) 35.3 nM and 10.2 nM, respectively) were successfully labeled with (11)C and evaluated as radioligands for mGluR1. The pharmacology of LY2428703 was comprehensively assessed in vitro and in vivo, and its biodistribution was investigated by liquid chromatography-mass spectrometry/mass spectrometry, and by PET imaging in the rat. In contrast, LSN2606428 was only evaluated in vitro; further evaluation was stopped due to its unfavorable pharmacological properties and binding affinity. RESULTS (11)C-LY2428703 showed promising characteristics, including: (1) high potency for binding to human mGluR1 (IC(50) 8.9 nM) with no significant affinity for other human mGlu receptors (mGluR2 through mGluR8); (2) binding to brain displaceable by administration of an mGluR1 antagonist; (3) only one major radiometabolite in both plasma and brain, with a negligible brain concentration (with 3.5 % of the total radioactivity in cerebellum) and no receptor affinity; (4) a large specific and displaceable signal in the mGluR1-rich cerebellum with no significant in vivo affinity for mGluR5, as shown by PET studies in rats; and (5) lack of substrate behavior for efflux transporters at the blood-brain barrier, as shown by PET studies conducted in wild-type and knockout mice. CONCLUSION (11)C-LY2428703, a new PET radioligand for mGluR1 quantification, displayed promising characteristics both in vitro and in vivo in rodents.
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Affiliation(s)
- Paolo Zanotti-Fregonara
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA
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14
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Pedregal C, Joshi EM, Toledo MA, Lafuente C, Diaz N, Martinez-Grau MA, Jiménez A, Benito A, Navarro A, Chen Z, Mudra DR, Kahl SD, Rash KS, Statnick MA, Barth VN. Development of LC-MS/MS-Based Receptor Occupancy Tracers and Positron Emission Tomography Radioligands for the Nociceptin/Orphanin FQ (NOP) Receptor. J Med Chem 2012; 55:4955-67. [DOI: 10.1021/jm201629q] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Concepción Pedregal
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Elizabeth M. Joshi
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Miguel A. Toledo
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Celia Lafuente
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Nuria Diaz
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Maria A. Martinez-Grau
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Alma Jiménez
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Ana Benito
- Centro de
Investigación Lilly, Avenida de la Industria 30, 28108-Alcobendas,
Madrid, Spain
| | - Antonio Navarro
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Zhaogen Chen
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Daniel R. Mudra
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Steven D. Kahl
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Karen S. Rash
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Michael A. Statnick
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Vanessa N. Barth
- Eli Lilly & Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
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15
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Lohith TG, Zoghbi SS, Morse CL, Araneta MF, Barth VN, Goebl NA, Tauscher JT, Pike VW, Innis RB, Fujita M. Brain and whole-body imaging of nociceptin/orphanin FQ peptide receptor in humans using the PET ligand 11C-NOP-1A. J Nucl Med 2012; 53:385-92. [PMID: 22312136 PMCID: PMC3835399 DOI: 10.2967/jnumed.111.097162] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Nociceptin/orphanin FQ peptide (NOP) receptor is a new class of opioid receptor that may play a pathophysiologic role in anxiety and drug abuse and is a potential therapeutic target in these disorders. We previously developed a high-affinity PET ligand, (11)C-NOP-1A, which yielded promising results in monkey brain. Here, we assessed the ability of (11)C-NOP-1A to quantify NOP receptors in human brain and estimated its radiation safety profile. METHODS After intravenous injection of (11)C-NOP-1A, 7 healthy subjects underwent brain PET for 2 h and serial sampling of radial arterial blood to measure parent radioligand concentrations. Distribution volume (V(T); a measure of receptor density) was determined by compartmental (1- and 2-tissue) and noncompartmental (Logan analysis and Ichise's bilinear analysis [MA1]) methods. A separate group of 9 healthy subjects underwent whole-body PET to estimate whole-body radiation exposure (effective dose). RESULTS After (11)C-NOP-1A injection, the peak concentration of radioactivity in brain was high (∼5-7 standardized uptake values), occurred early (∼10 min), and then washed out quickly. The unconstrained 2-tissue-compartment model gave excellent V(T) identifiability (∼1.1% SE) and fitted the data better than a 1-tissue-compartment model. Regional V(T) values (mL·cm(-3)) ranged from 10.1 in temporal cortex to 5.6 in cerebellum. V(T) was well identified in the initial 70 min of imaging and remained stable for the remaining 50 min, suggesting that brain radioactivity was most likely parent radioligand, as supported by the fact that all plasma radiometabolites of (11)C-NOP-1A were less lipophilic than the parent radioligand. Voxel-based MA1 V(T) values correlated well with results from the 2-tissue-compartment model, showing that parametric methods can be used to compare populations. Whole-body scans showed radioactivity in brain and in peripheral organs expressing NOP receptors, such as heart, pancreas, and spleen. (11)C-NOP-1A was significantly metabolized and excreted via the hepatobiliary route. Gallbladder had the highest radiation exposure (21 μSv/MBq), and the effective dose was 4.3 μSv/MBq. CONCLUSION (11)C-NOP-1A is a promising radioligand that reliably quantifies NOP receptors in human brain. The effective dose in humans is low and similar to that of other (11)C-labeled radioligands, allowing multiple scans in 1 subject.
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Affiliation(s)
- Talakad G. Lohith
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Sami S. Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Cheryl L. Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Maria F. Araneta
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | | | | | | | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Robert B. Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
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Mitch CH, Quimby SJ, Diaz N, Pedregal C, de la Torre MG, Jimenez A, Shi Q, Canada EJ, Kahl SD, Statnick MA, McKinzie DL, Benesh DR, Rash KS, Barth VN. Discovery of aminobenzyloxyarylamides as κ opioid receptor selective antagonists: application to preclinical development of a κ opioid receptor antagonist receptor occupancy tracer. J Med Chem 2011; 54:8000-12. [PMID: 21958337 DOI: 10.1021/jm200789r] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Arylphenylpyrrolidinylmethylphenoxybenzamides were found to have high affinity and selectivity for κ opioid receptors. On the basis of receptor binding assays in Chinese hamster ovary (CHO) cells expressing cloned human opioid receptors, (S)-3-fluoro-4-(4-((2-(3-fluorophenyl)pyrrolidin-1-yl)methyl)phenoxy)benzamide (25) had a K(i) = 0.565 nM for κ opioid receptor binding while having a K(i) = 35.8 nM for μ opioid receptors and a K(i) = 211 nM for δ opioid receptor binding. Compound 25 was also a potent antagonist of κ opioid receptors when tested in vitro using a [(35)S]-guanosine 5'O-[3-thiotriphosphate] ([(35)S]GTP-γ-S) functional assay in CHO cells expressing cloned human opioid receptors. Compounds were also evaluated for potential use as receptor occupancy tracers. Tracer evaluation was done in vivo, using liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods, precluding the need for radiolabeling. (S)-3-Chloro-4-(4-((2-(pyridine-3-yl)pyrrolidin-1-yl)methyl)phenoxy)benzamide (18) was found to have favorable properties for a tracer for receptor occupancy, including good specific versus nonspecific binding and good brain uptake.
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Affiliation(s)
- Charles H Mitch
- Lilly Research Laboratories, Lilly Corporate Center, Eli Lilly and Company, Indianapolis, Indiana 46285-0150, United States.
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Kimura Y, Fujita M, Hong J, Lohith TG, Gladding RL, Zoghbi SS, Tauscher JA, Goebl N, Rash KS, Chen Z, Pedregal C, Barth VN, Pike VW, Innis RB. Brain and whole-body imaging in rhesus monkeys of 11C-NOP-1A, a promising PET radioligand for nociceptin/orphanin FQ peptide receptors. J Nucl Med 2011; 52:1638-45. [PMID: 21880575 DOI: 10.2967/jnumed.111.091181] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Our laboratory developed (S)-3-(2'-fluoro-6',7'-dihydrospiro[piperidine-4,4'-thieno[3,2-c]pyran]-1-yl)-2-(2-fluorobenzyl)-N-methylpropanamide ((11)C-NOP-1A), a new radioligand for the nociceptin/orphanin FQ peptide (NOP) receptor, with high affinity (K(i), 0.15 nM) and appropriate lipophilicity (measured logD, 3.4) for PET brain imaging. Here, we assessed the utility of (11)C-NOP-1A for quantifying NOP receptors in the monkey brain and estimated the radiation safety profile of this radioligand based on its biodistribution in monkeys. METHODS Baseline and blocking PET scans were acquired from head to thigh for 3 rhesus monkeys for approximately 120 min after (11)C-NOP-1A injection. These 6 PET scans were used to quantify NOP receptors in the brain and to estimate radiation exposure to organs of the body. In the blocked scans, a selective nonradioactive NOP receptor antagonist (SB-612111; 1 mg/kg intravenously) was administered before (11)C-NOP-1A. In all scans, arterial blood was sampled to measure the parent radioligand (11)C-NOP-1A. Distribution volume (V(T); a measure of receptor density) was calculated with a compartment model using brain and arterial plasma data. Radiation-absorbed doses were calculated using the MIRD Committee scheme. RESULTS After (11)C-NOP-1A injection, peak uptake of radioactivity in the brain had a high concentration (∼5 standardized uptake value), occurred early (∼12 min), and thereafter washed out quickly. V(T) (mL · cm(-3)) was highest in the neocortex (∼20) and lowest in hypothalamus and cerebellum (∼13). SB-612111 blocked approximately 50%-70% of uptake and reduced V(T) in all brain regions to approximately 7 mL · cm(-3). Distribution was well identified within 60 min of injection and stable for the remaining 60 min, consistent with only parent radioligand and not radiometabolites entering the brain. Whole-body scans confirmed that the brain had specific (i.e., displaceable) binding but could not detect specific binding in peripheral organs. The effective dose for humans estimated from the baseline scans in monkeys was 5.0 μSv/MBq. CONCLUSION (11)C-NOP-1A is a useful radioligand for quantifying NOP receptors in the monkey brain, and its radiation dose is similar to that of other (11)C-labeled ligands for neuroreceptors. (11)C-NOP-1A appears to be a promising candidate for measuring NOP receptors in the human brain.
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Affiliation(s)
- Yasuyuki Kimura
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1026, USA
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18
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Pike VW, Rash KS, Chen Z, Pedregal C, Statnick MA, Kimura Y, Hong J, Zoghbi SS, Fujita M, Toledo MA, Diaz N, Gackenheimer SL, Tauscher JT, Barth VN, Innis RB. Synthesis and evaluation of radioligands for imaging brain nociceptin/orphanin FQ peptide (NOP) receptors with positron emission tomography. J Med Chem 2011; 54:2687-700. [PMID: 21438532 PMCID: PMC3081360 DOI: 10.1021/jm101487v] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Positron emission tomography (PET) coupled to an effective radioligand could provide an important tool for understanding possible links between neuropsychiatric disorders and brain NOP (nociceptin/orphanin FQ peptide) receptors. We sought to develop such a PET radioligand. High-affinity NOP ligands were synthesized based on a 3-(2'-fluoro-4',5'-dihydrospiro[piperidine-4,7'-thieno[2,3-c]pyran]-1-yl)-2(2-halobenzyl)-N-alkylpropanamide scaffold and from experimental screens in rats, with ex vivo LC-MS/MS measures, three ligands were identified for labeling with carbon-11 and evaluation with PET in monkey. Each ligand was labeled by (11)C-methylation of an N-desmethyl precursor and studied in monkey under baseline and NOP receptor-preblock conditions. The three radioligands, [(11)C](S)-10a-c, gave similar results. Baseline scans showed high entry of radioactivity into the brain to give a distribution reflecting that expected for NOP receptors. Preblock experiments showed high early peak levels of brain radioactivity, which rapidly declined to a much lower level than seen in baseline scans, thereby indicating a high level of receptor-specific binding in baseline experiments. Overall, [(11)C](S)-10c showed the most favorable receptor-specific signal and kinetics and is now selected for evaluation in human subjects.
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Affiliation(s)
- Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States.
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Fell MJ, Perry KW, Falcone JF, Johnson BG, Barth VN, Rash KS, Lucaites VL, Threlkeld PG, Monn JA, McKinzie DL, Marek GJ, Svensson KA, Nelson DL. In vitro and in vivo evidence for a lack of interaction with dopamine D2 receptors by the metabotropic glutamate 2/3 receptor agonists 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicaroxylate monohydrate (LY354740) and (-)-2-oxa-4-aminobicyclo[3.1.0] Hexane-4,6-dicarboxylic acid (LY379268). J Pharmacol Exp Ther 2009; 331:1126-36. [PMID: 19755662 DOI: 10.1124/jpet.109.160598] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Some recently published in vitro studies with two metabotropic glutamate 2/3 receptor (mGluR(2/3)) agonists [(-)-2-oxa-4-aminobicyclo[3.1.0] hexane-4,6-dicarboxylic acid (LY379268) and 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicaroxylate monohydrate (LY354740)] suggest that these compounds may also directly interact with dopamine (DA) D(2) receptors. The current in vitro and in vivo studies were undertaken to further explore this potential interaction with D(2) receptors. LY379268 and LY354740 failed to inhibit D(2) binding in both native striatal tissue homogenates and cloned receptors at concentrations up to 10 microM. LY379268 and LY354740 (up to 10 microM) also failed to stimulate [(35)S]GTPgammaS binding in D(2L)- and D(2S)-expressing clones in the presence of NaCl or N-methyl-d-glucamine. In an in vivo striatal D(2) receptor occupancy assay, LY379268 (3-30 mg/kg) or LY354740 (1-10 mg/kg) failed to displace raclopride (3 microg/kg i.v.), whereas aripiprazole (10-60 mg/kg) showed up to 90% striatal D(2) receptor occupancy. LY379268 (10 mg/kg) and raclopride (3 mg/kg) blocked d-amphetamine and phencyclidine (PCP)-induced hyperactivity in wild-type mice. However, the effects of LY379268 were lost in mGlu(2/3) receptor knockout mice. In DA D(2) receptor-deficient mice, LY379268 but not raclopride blocked both PCP and d-amphetamine-evoked hyperactivity. In the striatum and nucleus accumbens, LY379268 (3 and 10 mg/kg) was without effect on the DA synthesis rate in reserpinized rats and also failed to prevent S-(-)-3-(3-hydroxyphenyl)-N-propylpiperidine-induced reductions in DA synthesis rate. Taken together, the current data fail to show evidence of direct DA D(2) receptor interactions of LY379268 and LY354740 in vitro or in vivo. Instead, these results provide further evidence for a novel antipsychotic mechanism of action for mGluR(2/3) agonists.
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Affiliation(s)
- Matthew J Fell
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.
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Barth VN, Chernet E, Martin LJ, Need AB, Rash KS, Morin M, Phebus LA. Comparison of rat dopamine D2 receptor occupancy for a series of antipsychotic drugs measured using radiolabeled or nonlabeled raclopride tracer. Life Sci 2006; 78:3007-12. [PMID: 16434058 DOI: 10.1016/j.lfs.2005.11.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 11/18/2005] [Accepted: 11/27/2005] [Indexed: 11/24/2022]
Abstract
Preclinical brain receptor occupancy measures have heretofore been conducted by quantifying the brain distribution of a radiolabeled tracer ligand using either scintillation spectroscopy or tomographic imaging. For smaller animals like rodents, the majority of studies employ tissue dissection and scintillation spectroscopy. These measurements can also be accomplished using liquid chromatography coupled to mass spectral detection to measure the brain distribution of tracer molecules, obviating the need for radioligands. In order to validate mass spectroscopy-based receptor occupancy methods, we examined dopamine D2 receptor dose-occupancy curves for a number of antipsychotic drugs in parallel experiments using either mass spectroscopy or radioligand-based approaches. Oral dose-occupancy curves were generated for 8 antipsychotic compounds in parallel experiments using either radiolabeled or unlabeled raclopride tracer. When curves generated by these two methods were compared and ED(50) values determined, remarkably similar data were obtained. Occupancy ED(50) values were (mg/kg): chlorpromazine, 5.1 and 2.7; clozapine, 41 and 40; haloperidol, 0.2 and 0.3; olanzapine, 2.1 and 2.2; risperidone, 0.1 and 0.4; spiperone, 0.5 and 0.4; thioridazine 9.2 and 9.5; and ziprasidone 1.4 and 2.1 (unlabeled and radiolabeled raclopride tracer, respectively). The observation that in vivo application of both techniques led to comparable data adds to the validation state of the mass spectroscopy-based approach to receptor occupancy assays.
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Affiliation(s)
- Vanessa N Barth
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, 46285, USA
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Chernet E, Martin LJ, Li D, Need AB, Barth VN, Rash KS, Phebus LA. Use of LC/MS to assess brain tracer distribution in preclinical, in vivo receptor occupancy studies: Dopamine D2, serotonin 2A and NK-1 receptors as examples. Life Sci 2005; 78:340-6. [PMID: 16139310 DOI: 10.1016/j.lfs.2005.04.075] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 04/22/2005] [Indexed: 11/19/2022]
Abstract
High performance liquid chromatography combined with either single quad or triple quad mass spectral detectors (LC/MS) was used to measure the brain distribution of receptor occupancy tracers targeting dopamine D2, serotonin 5-HT2A and neurokinin NK-1 receptors using the ligands raclopride, MDL-100907 and GR205171, respectively. All three non-radiolabeled tracer molecules were easily detectable in discrete rat brain areas after intravenous doses of 3, 3 and 30 microg/kg, respectively. These levels showed a differential brain distribution caused by differences in receptor density, as demonstrated by the observation that pretreatment with compounds that occupy these receptors reduced this differential distribution in a dose-dependent manner. Intravenous, subcutaneous and oral dose-occupancy curves were generated for haloperidol at the dopamine D2 receptor as were oral curves for the antipsychotic drugs olanzapine and clozapine. In vivo dose-occupancy curves were also generated for orally administered clozapine, olanzapine and haloperidol at the cortical 5-HT2A binding site. In vivo occupancy at the striatal neurokinin NK-1 binding site by various doses of orally administered MK-869 was also measured. Our results demonstrate the utility of LC/MS to quantify tracer distribution in preclinical brain receptor occupancy studies.
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Affiliation(s)
- Eyassu Chernet
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana 46285, USA
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Seager MA, Barth VN, Phebus LA, Rasmussen K. Chronic coadministration of olanzapine and fluoxetine activates locus coeruleus neurons in rats: implications for bipolar disorder. Psychopharmacology (Berl) 2005; 181:126-33. [PMID: 15719213 DOI: 10.1007/s00213-005-2198-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Accepted: 01/18/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE The depressive phase of bipolar disorder (bipolar depression) is a difficult-to-treat form of depression. The olanzapine/fluoxetine combination (Symbyax) is the only medication approved to treat this disorder. The precise neural mechanisms responsible for its efficacy are not clearly understood. OBJECTIVES In order to further elucidate the neurobiological mechanisms responsible for the beneficial clinical effects of the olanzapine/fluoxetine combination, the current experiment was designed to investigate the effects of chronic coadministration of olanzapine and fluoxetine on electrophysiological activity in the locus coeruleus (LC). METHODS Rats received olanzapine for 3 weeks via subcutaneous osmotic pumps while simultaneously receiving daily intraperitoneal injections of fluoxetine. These chronically treated rats were anesthetized, and single-unit recordings of LC neurons were made. RESULTS Chronic administration of olanzapine alone significantly increased firing of LC neurons, while, as reported previously, chronic administration of fluoxetine alone significantly reduced firing of LC neurons. However, in the combination condition, olanzapine was able to block the fluoxetine-induced suppression of the LC, and a significant increase in LC activity was observed. CONCLUSIONS The observed increase in firing of LC neurons could lead to enhanced levels of norepinephrine release in projection areas and amelioration of the clinical symptoms of bipolar depression.
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Affiliation(s)
- Matthew A Seager
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA
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Seager MA, Huff KD, Barth VN, Phebus LA, Rasmussen K. Fluoxetine administration potentiates the effect of olanzapine on locus coeruleus neuronal activity. Biol Psychiatry 2004; 55:1103-9. [PMID: 15158430 DOI: 10.1016/j.biopsych.2004.02.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Revised: 02/09/2004] [Accepted: 02/12/2004] [Indexed: 11/24/2022]
Abstract
BACKGROUND As many as 30% of individuals diagnosed with depression are nonresponsive to traditional antidepressant medication. Augmentation and combination strategies have emerged in an attempt to address this issue. Atypical antipsychotics (e.g., olanzapine), when added to a selective serotonin reuptake inhibitor (e.g., fluoxetine) have shown great promise in the treatment of these treatment-resistant patients. As of yet, the precise neural mechanisms responsible for the beneficial clinical effect of these combinations are not completely understood. METHODS Separate groups of rats received either saline or fluoxetine (10 mg/kg/day) for 24 hours or 3 weeks via subcutaneously implanted osmotic pumps. The effects of either intravenous saline or olanzapine (.3, 1.0, or 3.0 mg/kg) on locus coeruleus (LC) neuronal activity were then assessed via extracellular single-unit recordings. RESULTS Acute administration of olanzapine produced a significant elevation of the firing rate and burst firing of LC cells, and chronic, but not acute, administration of fluoxetine decreased baseline and burst firing of LC cells; however, when given in combination, an interaction of fluoxetine and olanzapine was observed, with olanzapine causing a significantly greater increase in LC firing rate and burst firing after acute and chronic administration of fluoxetine. CONCLUSIONS These results provide a potential neural mechanism for the beneficial clinical effects of the olanzapine/fluoxetine combination. The increase in baseline and burst firing of LC neurons in the groups receiving both fluoxetine and olanzapine would result in enhanced norepinephrine release in projection areas (e.g., prefrontal cortex), which could lead to a reduction in depressive symptoms.
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Affiliation(s)
- Matthew A Seager
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA
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