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Swenson CS, Pillai KS, Carlos AJ, Moellering RE. Spatial Chemoproteomics for Mapping the Active Proteome. Isr J Chem 2023; 63:e202200104. [PMID: 38046285 PMCID: PMC10688764 DOI: 10.1002/ijch.202200104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Indexed: 01/06/2023]
Abstract
Functional regulation of cell signaling through dynamic changes in protein activity state as well as spatial organization represent two dynamic, complex, and conserved phenomena in biology. Seemingly separate areas of -omics method development have focused on building tools that can detect and quantify protein activity states, as well as map sub-cellular and intercellular protein organization. Integration of these efforts, through the development of chemical tools and platforms that enable detection and quantification of protein functional states with spatial resolution provide opportunities to better understand heterogeneity in the proteome within cell organelles, multi-cellular tissues, and whole organisms. This review provides an overview of and considerations for major classes of chemical proteomic probes and technologies that enable protein activity mapping from sub-cellular compartments to live animals.
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Affiliation(s)
- Colin S Swenson
- Department of Chemistry, University of Chicago, 5735 S Ellis Dr. Chicago, IL 60637, USA
| | - Kavya Smitha Pillai
- Department of Chemistry, University of Chicago, 5735 S Ellis Dr. Chicago, IL 60637, USA
| | - Anthony J Carlos
- Department of Chemistry, University of Chicago, 5735 S Ellis Dr. Chicago, IL 60637, USA
| | - Raymond E Moellering
- Department of Chemistry, University of Chicago, 5735 S Ellis Dr. Chicago, IL 60637, USA
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2
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Ferreira PC, Bellaver B, Povala G, Brum WS, Tissot C, Badji A, Sloan ME, Benedet AL, Rosa-Neto P, Ashton NJ, Pascoal TA, Leuzy A, Zimmer ER. Endocannabinoid System Biomarkers in Alzheimer's Disease. Cannabis Cannabinoid Res 2023; 8:77-91. [PMID: 36394442 PMCID: PMC10081722 DOI: 10.1089/can.2022.0151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background: Alterations in the endocannabinoid system (ES) have been described in Alzheimer's disease (AD) pathophysiology. In the past years, multiple ES biomarkers have been developed, promising to advance our understanding of ES changes in AD. Discussion: ES biomarkers, including positron emission tomography with cannabinoid receptors tracers and biofluid-based endocannabinoids, are associated with AD disease progression and pathological features. Conclusion: Although not specific enough for AD diagnosis, ES biomarkers hold promise for prognosis, drug-target engagement, and a better understanding of the disease. Here, we summarize currently available ES biomarker findings and discuss their potential applications in the AD research field.
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Affiliation(s)
- Pâmela C.L. Ferreira
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Bruna Bellaver
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Guilherme Povala
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Wagner S. Brum
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Cécile Tissot
- Department of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Alzheimer's Disease Research Unit, Douglas Research Institute, Le Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l'Ouest-de-l'Île-de-Montréal, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, Psychiatry and Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Atef Badji
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
- Karolinska University Hospital, Theme Aging, Huddinge, Sweden
| | - Matthew E. Sloan
- Addictions Division, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Division of Neurosciences and Clinical Translation, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
- Department of Psychological Clinical Science, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Andréa L. Benedet
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Alzheimer's Disease Research Unit, Douglas Research Institute, Le Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l'Ouest-de-l'Île-de-Montréal, Montreal, QC, Canada
- Department of Neurology and Neurosurgery, Psychiatry and Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Nicholas J. Ashton
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
- King's College London, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Institute Clinical Neuroscience Institute, London, United Kingdom
- NIHR Biomedical Research Centre for Mental Health and Biomedical Research Unit for Dementia at South London and Maudsley NHS Foundation, London, United Kingdom
| | - Tharick A. Pascoal
- Department of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Antoine Leuzy
- Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Eduardo R. Zimmer
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Alzheimer's Disease Research Unit, Douglas Research Institute, Le Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l'Ouest-de-l'Île-de-Montréal, Montreal, QC, Canada
- Department of Pharmacology, UFRGS, Porto Alegre, Brazil
- Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil
- Brain Institute of Rio Grande do Sul, PUCRS, Porto Alegre, Brazil
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3
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Santoso AD, De Ridder D. Fatty Acid Amide Hydrolase: An Integrative Clinical Perspective. Cannabis Cannabinoid Res 2023; 8:56-76. [PMID: 35900294 DOI: 10.1089/can.2021.0237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Introduction: Fatty acid amide hydrolase (FAAH) is one of the main terminating enzymes of the endocannabinoid system (ECS). Since being discovered in 1996, the modulation of FAAH has been viewed as a compelling alternative strategy to obtain the beneficial effect of the ECS. With a considerable amount of FAAH-related publication over time, the next step would be to comprehend the proximity of this evidence for clinical application. Objective: This review intends to highlight the rationale of FAAH modulation and provide the latest evidence from clinical studies. Methods: Publication searches were conducted to gather information focused on FAAH-related clinical evidence with an extension to the experimental research to understand the biological plausibility. The subtopics were selected to be multidisciplinary to offer more perspective on the current state of the arts. Discussion: Experimental and clinical studies have demonstrated that FAAH was highly expressed not only in the central nervous system but also in the peripheral tissues. As the key regulator of endocannabinoid signaling, it would appear that FAAH plays a role in the modulation of mood and emotional response, reward system, pain perception, energy metabolism and appetite regulation, inflammation, and other biological processes. Genetic variants may be associated with some conditions such as substance/alcohol use disorders, obesity, and eating disorder. The advancement of functional neuroimaging has enabled the evaluation of the neurochemistry of FAAH in brain tissues and this can be incorporated into clinical trials. Intriguingly, the application of FAAH inhibitors in clinical trials seems to provide less striking results in comparison with the animal models, although some potential still can be seen. Conclusion: Modulation of FAAH has an immense potential to be a new therapeutic candidate for several disorders. Further exploration, however, is still needed to ensure who is the best candidate for the treatment strategy.
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Affiliation(s)
- Anugrah D Santoso
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
- Department of Urology, Faculty of Medicine Universitas Airlangga, Dr. Soetomo General Academic Hospital, Surabaya, Indonesia
| | - Dirk De Ridder
- Laboratory of Experimental Urology, Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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4
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Hou L, Rong J, Haider A, Ogasawara D, Varlow C, Schafroth MA, Mu L, Gan J, Xu H, Fowler CJ, Zhang MR, Vasdev N, Ametamey S, Cravatt BF, Wang L, Liang SH. Positron Emission Tomography Imaging of the Endocannabinoid System: Opportunities and Challenges in Radiotracer Development. J Med Chem 2020; 64:123-149. [PMID: 33379862 DOI: 10.1021/acs.jmedchem.0c01459] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocannabinoid system (ECS) is involved in a wide range of biological functions and comprises cannabinoid receptors and enzymes responsible for endocannabinoid synthesis and degradation. Over the past 2 decades, significant advances toward developing drugs and positron emission tomography (PET) tracers targeting different components of the ECS have been made. Herein, we summarized the recent development of PET tracers for imaging cannabinoid receptors 1 (CB1R) and 2 (CB2R) as well as the key enzymes monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), particularly focusing on PET neuroimaging applications. State-of-the-art PET tracers for the ECS will be reviewed including their chemical design, pharmacological properties, radiolabeling, as well as preclinical and human PET imaging. In addition, this review addresses the current challenges for ECS PET biomarker development and highlights the important role of PET ligands to study disease pathophysiology as well as to facilitate drug discovery.
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Affiliation(s)
- Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ahmed Haider
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Cassis Varlow
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Michael A Schafroth
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States.,Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health, and Department of Psychiatry/Institute of Medical Science, University of Toronto, 250 College Street, Toronto, M5T 1R8 ON, Canada
| | - Simon Ametamey
- Center for Radiopharmaceutical Sciences of ETH, PSI, and USZ, and Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, SR107, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, 613 West Huangpu Road, Tianhe District, Guangzhou 510630, China.,Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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5
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Chen Z, Hou L, Gan J, Cai Q, Ye W, Chen J, Tan Z, Zheng C, Li G, Xu H, Fowler CJ, Liang SH, Wang L. Synthesis and preliminary evaluation of a novel positron emission tomography (PET) ligand for imaging fatty acid amide hydrolase (FAAH). Bioorg Med Chem Lett 2020; 30:127513. [PMID: 32860981 DOI: 10.1016/j.bmcl.2020.127513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/14/2020] [Accepted: 08/20/2020] [Indexed: 01/09/2023]
Abstract
Fatty acid amide hydrolase (FAAH) exerts its main function in the catabolism of the endogenous chemical messenger anandamide (AEA), thus modulating the endocannabinoid (eCB) pathway. Inhibition of FAAH may serve as an effective strategy to relieve anxiety and possibly other central nervous system (CNS)-related disorders. Positron emission tomography (PET) would facilitate us to better understand the relationship between FAAH in certain disease conditions, and accelerate clinical translation of FAAH inhibitors by providing in vivo quantitative information. So far, most PET tracers show irreversible binding patterns with FAAH, which would result in complicated quantitative processes. Herein, we have identified a new FAAH inhibitor (1-((1-methyl-1H-indol-2-yl)methyl)piperidin-4-yl)(oxazol-2-yl)methanone (8) which inhibits the hydrolysis of AEA in the brain with high potency (IC50 value 11 nM at a substrate concentration of 0.5 µM), and without showing time-dependency. The PET tracer [11C]8 (also called [11C]FAAH-1906) was successfully radiolabeled with [11C]MeI in 17 ± 6% decay-corrected radiochemical yield (n = 7) with >74.0 GBq/μmol (2 Ci/μmol) molar activity and >99% radiochemical purity. Ex vivo biodistribution and blocking studies of [11C]8 in normal mice were also conducted, indicating good brain penetration, high brain target selectivity, and modest to excellent target selectivity in peripheral tissues. Thus, [11C]8 is a potentially useful PET ligand with enzyme inhibitory and target binding properties consistent with a reversible mode of action.
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Affiliation(s)
- Zhen Chen
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Jiefeng Gan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Qijun Cai
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Weijian Ye
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Jiahui Chen
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Zhiqiang Tan
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Chao Zheng
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Charlestown, Boston, MA 02129, USA
| | - Guocong Li
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Christopher J Fowler
- Department of Integrative Medical Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA 02114, USA.
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine and PET/CT-MRI Center, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
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6
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Abstract
Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents.
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Affiliation(s)
- Brian P Rempel
- 1 Department of Science, Augustana Faculty, University of Alberta, Edmonton, Alberta, Canada
| | - Eric W Price
- 2 Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Christopher P Phenix
- 2 Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.,3 Biomarker Discovery, Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
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7
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Yuan Y, Wang F, Tang W, Ding Z, Wang L, Liang L, Zheng Z, Zhang H, Liang G. Intracellular Self-Assembly of Cyclic d-Luciferin Nanoparticles for Persistent Bioluminescence Imaging of Fatty Acid Amide Hydrolase. ACS NANO 2016; 10:7147-7153. [PMID: 27348334 DOI: 10.1021/acsnano.6b03412] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fatty acid amide hydrolase (FAAH) overexpression induces several disorder symptoms in nerve systems, and therefore long-term tracing of FAAH activity in vivo is of high importance but remains challenging. Current bioluminescence (BL) methods are limited in detecting FAAH activity within 5 h. Herein, by rational design of a latent BL probe (d-Cys-Lys-CBT)2 (1), we developed a "smart" method of intracellular reduction-controlled self-assembly and FAAH-directed disassembly of its cyclic d-luciferin-based nanoparticles (i.e., 1-NPs) for persistent BL imaging of FAAH activity in vitro, in cells, and in vivo. Using aminoluciferin methyl amide (AMA), Lys-amino-d-luciferin (Lys-Luc), and amino-d-luciferin (NH2-Luc) as control BL probes, we validated that the persistent BL of 1 from luciferase-expressing cells or tumors was controlled by the activity of intracellular FAAH. With the property of long-term tracing of FAAH activity in vivo of 1, we envision that our BL precursor 1 could probably be applied for in vivo screening of FAAH inhibitors and the diagnosis of their related diseases (or disorders) in the future.
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Affiliation(s)
- Yue Yuan
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Fuqiang Wang
- State Key Laboratory of Reproductive Medicine, Analysis Center, Nanjing Medical University , Nanjing, Jiangsu 210093, China
| | - Wei Tang
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Zhanling Ding
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Lin Wang
- School of Life Sciences, University of Science and Technology of China , Hefei, Anhui 230027, China
| | - Lili Liang
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Zhen Zheng
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
| | - Huafeng Zhang
- School of Life Sciences, University of Science and Technology of China , Hefei, Anhui 230027, China
| | - Gaolin Liang
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , 96 Jinzhai Road, Hefei, Anhui 230026, China
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8
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Wang L, Yui J, Wang Q, Zhang Y, Mori W, Shimoda Y, Fujinaga M, Kumata K, Yamasaki T, Hatori A, Rotstein BH, Collier TL, Ran C, Vasdev N, Zhang MR, Liang SH. Synthesis and Preliminary PET Imaging Studies of a FAAH Radiotracer ([¹¹C]MPPO) Based on α-Ketoheterocyclic Scaffold. ACS Chem Neurosci 2016; 7:109-18. [PMID: 26505525 DOI: 10.1021/acschemneuro.5b00248] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is one of the principle enzymes for metabolizing endogenous cannabinoid neurotransmitters such as anandamide, and thus regulates endocannabinoid (eCB) signaling. Selective pharmacological blockade of FAAH has emerged as a potential therapy to discern the endogenous functions of anandamide-mediated eCB pathways in anxiety, pain, and addiction. Quantification of FAAH in the living brain by positron emission tomography (PET) would help our understanding of the endocannabinoid system in these conditions. While most FAAH radiotracers operate by an irreversible ("suicide") binding mechanism, a FAAH tracer with reversibility would facilitate quantitative analysis. We have identified and radiolabeled a reversible FAAH inhibitor, 7-(2-[(11)C]methoxyphenyl)-1-(5-(pyridin-2-yl)oxazol-2-yl)heptan-1-one ([(11)C]MPPO) in 13% radiochemical yield (nondecay corrected) with >99% radiochemical purity and 2 Ci/μmol (74 GBq/μmol) specific activity. The tracer showed moderate brain uptake (0.8 SUV) with heterogeneous brain distribution. However, blocking studies with a potent FAAH inhibitor URB597 demonstrated a low to modest specificity to the target. Measurement of lipophilicity, metabolite, and efflux pathway analysis were also performed to study the pharmacokinetic profile of [(11)C]MPPO. In all, we reported an efficient radiolabeling and preliminary evaluation of the first-in-class FAAH inhibitor [(11)C]MPPO with α-ketoheterocyclic scaffold.
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Affiliation(s)
- Lu Wang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Joji Yui
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Qifan Wang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Yiding Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Wakana Mori
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Yoko Shimoda
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Akiko Hatori
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Benjamin H. Rotstein
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Thomas Lee Collier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
- Advion BioSystems, 10 Brown Road, Suite 101, Ithaca, New York 14850, United States
| | - Chongzhao Ran
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Charlestown, Massachusetts 02129, United States
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Ming-Rong Zhang
- Molecular
Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Steven H. Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, Massachusetts 02114, United States
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9
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Shoup TM, Bonab AA, Wilson AA, Vasdev N. Synthesis and preclinical evaluation of [¹⁸F]FCHC for neuroimaging of fatty acid amide hydrolase. Mol Imaging Biol 2015; 17:257-63. [PMID: 25273322 DOI: 10.1007/s11307-014-0789-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE Fatty acid amide hydrolase (FAAH), a catabolic enzyme which regulates lipid transmitters in the endocannabinoid system, is an avidly sought therapeutic and positron emission tomography (PET) imaging target for studies involving addiction and neurological disorders. We report the synthesis of a new fluorine-18-labeled FAAH inhibitor, trans-3-(4, 5-dihydrooxazol-2-yl)phenyl-4-[(18)F]fluorocyclohexylcarbamate ([(18)F]FCHC), and its evaluation in rat brain. PROCEDURES The synthesis of [(18)F]FCHC was conducted via a 3-step, 1-pot reaction, resulting in uncorrected radiochemical yields between 10 and 20% (n = 5) relative to [(18)F]fluoride, with specific activities of >5 Ci/μmol at the end of the synthesis. The radiosynthesis was seamlessly automated using a commercial radiofluorination apparatus. Ex vivo biodistribution and preliminary PET imaging studies were carried out in male Sprague-Dawley rats. RESULTS Rat brain biodistribution at 2 min post-injection showed a standard uptake value of 4.6 ± 0.1 in the cortex, which increased to 7.8 ± 0.1 at 40 min. Pretreatment with the selective FAAH inhibitor URB597 reduced uptake of radioactivity in all brain regions by >90%, with 98 % blockade in the FAAH-rich cortex. PET imaging was consistent with biodistribution studies. CONCLUSIONS [(18)F]FCHC appears to be a highly sensitive (18)F-labeled radiotracer for imaging FAAH in the central nervous system, and these results warrant further imaging in nonhuman primates.
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Affiliation(s)
- Timothy M Shoup
- Division of Nuclear Medicine and Molecular Imaging, Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, MA, USA
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10
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Abstract
Eukaryotic and prokaryotic organisms possess huge numbers of uncharacterized enzymes. Selective inhibitors offer powerful probes for assigning functions to enzymes in native biological systems. Here, we discuss how the chemical proteomic platform activity-based protein profiling (ABPP) can be implemented to discover selective and in vivo-active inhibitors for enzymes. We further describe how these inhibitors have been used to delineate the biochemical and cellular functions of enzymes, leading to the discovery of metabolic and signaling pathways that make important contributions to human physiology and disease. These studies demonstrate the value of selective chemical probes as drivers of biological inquiry.
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Affiliation(s)
- Micah J Niphakis
- The Skaggs Institute for Chemical Biology and the Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037;
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11
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Kniess T, Laube M, Brust P, Steinbach J. 2-[18F]Fluoroethyl tosylate – a versatile tool for building18F-based radiotracers for positron emission tomography. MEDCHEMCOMM 2015. [DOI: 10.1039/c5md00303b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The review highlights the role of 2-[18F]fluoroethyltosylate ([18F]FETs) in PET radiotracer design since it is a preferred labeling reagent according to its high reactivity to phenolic, amine, thiophenolic and carboxylic functions.
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Affiliation(s)
- Torsten Kniess
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
| | - Jörg Steinbach
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- Dresden
- Germany
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12
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Barth V, Need A. Identifying novel radiotracers for PET imaging of the brain: application of LC-MS/MS to tracer identification. ACS Chem Neurosci 2014; 5:1148-53. [PMID: 24828747 DOI: 10.1021/cn500072r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Nuclear medicine imaging biomarker applications are limited by the radiotracers available. Radiotracers enable the measurement of target engagement, or occupancy in relation to plasma exposure. These tracers can also be used as pharmacodynamic biomarkers to demonstrate functional consequences of binding a target. More recently, radiotracers have also been used for patient tailoring in Alzheimer's disease seen with amyloid imaging. Radiotracers for the central nervous system (CNS) are challenging to identify, as they require a unique intersection of multiple properties. Recent advances in tangential technologies, along with the use of iterative learning for the purposes of deriving in silico models, have opened up additional opportunities to identify radiotracers. Mass spectral technologies and in silico modeling have made it possible to measure and predict in vivo characteristics of molecules to indicate potential tracer performance. By analyzing these data alongside other measures, it is possible to delineate guidelines to increase the likelihood of selecting compounds that can perform as radiotracers or serve as the best starting point to develop a radiotracer following additional structural modification. The application of mass spectrometry based technologies is an efficient way to evaluate compounds as tracers in vivo, but more importantly enables the testing of potential tracers that have either no label site or complex labeling chemistry which may deter assessment by traditional means; therefore, use of this technology allows for more rapid iterative learning. The ability to differentially distribute toward target rich tissues versus tissue with no/less target present is a unique defining feature of a tracer. By testing nonlabeled compounds in vivo and analyzing tissue levels by LC-MS/MS, rapid assessment of a compound's ability to differentially distribute in a manner consistent with target expression biology guides the focus of chemistry resources for both designing and labeling tracer candidates. LC-MS/MS has only recently been used for de novo tracer identification; however, this connection of mass spectral technology to imaging has initiated engagement from a wider community that brings diverse backgrounds into the tracer discovery arena.
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Affiliation(s)
- Vanessa Barth
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Anne Need
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
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13
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Rotstein BH, Wey HY, Shoup TM, Wilson AA, Liang SH, Hooker JM, Vasdev N. PET imaging of fatty acid amide hydrolase with [(18)F]DOPP in nonhuman primates. Mol Pharm 2014; 11:3832-8. [PMID: 25004399 PMCID: PMC4224570 DOI: 10.1021/mp500316h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Fatty acid amide hydrolase (FAAH) regulates endocannabinoid signaling. [(11)C]CURB, an irreversibly binding FAAH inhibitor, has been developed for clinical research imaging with PET. However, no fluorine-18 labeled radiotracer for FAAH has yet advanced to human studies. [(18)F]DOPP ([(18)F]3-(4,5-dihydrooxazol-2-yl)phenyl (5-fluoropentyl)carbamate) has been identified as a promising (18)F-labeled analogue based on rodent studies. The goal of this work is to evaluate [(18)F]DOPP in nonhuman primates to support its clinical translation. High specific activity [(18)F]DOPP (5-6 Ci·μmol(-1)) was administered intravenously (iv) to three baboons (2M/1F, 3-4 years old). The distribution and pharmacokinetics were quantified following a 2 h dynamic imaging session using a simultaneous PET/MR scanner. Pretreatment with the FAAH-selective inhibitor, URB597, was carried out at 200 or 300 μg/kg iv, 10 min prior to [(18)F]DOPP administration. Rapid arterial blood sampling for the first 3 min was followed by interval sampling with metabolite analysis to provide a parent radiotracer plasma input function that indicated ∼95% baseline metabolism at 60 min and a reduced rate of metabolism after pretreatment with URB597. Regional distribution data were analyzed with 1-, 2-, and 3-tissue compartment models (TCMs), with and without irreversible trapping since [(18)F]DOPP covalently links to the active site of FAAH. Consistent with previous findings for [(11)C]CURB, the 2TCM with irreversible binding was found to provide the best fit for modeling the data in all regions. The composite parameter λk3 was therefore used to evaluate whole brain (WB) and regional binding of [(18)F]DOPP. Pretreatment studies showed inhibition of λk3 across all brain regions (WB baseline: 0.112 mL/cm(3)/min; 300 μg/kg URB597: 0.058 mL/cm(3)/min), suggesting that [(18)F]DOPP binding is specific for FAAH, consistent with previous rodent data.
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Affiliation(s)
- Benjamin H Rotstein
- Division of Nuclear Medicine and Molecular Imaging & Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital , Boston, Massachusetts 02114, United States
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14
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Hicks JW, Parkes J, Tong J, Houle S, Vasdev N, Wilson AA. Radiosynthesis and ex vivo evaluation of [(11)C-carbonyl]carbamate- and urea-based monoacylglycerol lipase inhibitors. Nucl Med Biol 2014; 41:688-94. [PMID: 24969632 DOI: 10.1016/j.nucmedbio.2014.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 04/16/2014] [Accepted: 05/01/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are the two primary enzymes that regulate the tone of endocannabinoid signaling. Although new PET radiotracers have been discovered for imaging FAAH in vivo, no such radiotracer exists for imaging MAGL. Here we report the radiosynthesis of five candidate MAGL radiotracers and their ex vivo evaluations in mice and rats. METHODS Candidate carbamate and urea MAGL inhibitors were radiolabeled at the carbonyl position by [(11)C]CO2 fixation. Radiotracers were administered (tail-vein injection) to rodents and brain uptake of radioactivity measured at early and late time points ex vivo. Specificity of uptake was explored by pretreatment with unlabeled inhibitors (2 mg/kg, ip) 30 min prior to radiotracer administration. RESULTS All five candidate MAGL radiotracers were prepared in high specific activity (>65 GBq/μmol) and radiochemical purity (>98%). Moderate brain uptake (0.2-0.8 SUV) was observed for each candidate while pretreatment did not reduce uptake for four of the five tested. For two candidates ([(11)C]12 and [(11)C]14), high retention of radioactivity was observed in the blood (ca. 10 and 4 SUV at 40 min) which was blocked by pretreatment with unlabeled inhibitors. The most promising candidate, [(11)C]18, demonstrated moderate brain uptake (ca. 0.8 SUV) which showed circa 50% blockade by pretreatment with unlabeled 18. CONCLUSION One putative and four reported potent and selective MAGL inhibitors have been radiolabeled via [(11)C]CO2 fixation as radiotracers for this enzyme. Despite the promising in vitro pharmacological profile, none of the five candidate radiotracers exhibited in vivo behavior suitable for PET neuroimaging.
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Affiliation(s)
- Justin W Hicks
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, M5T 1R8; Institute of Medical Science, University of Toronto, Toronto, ON, Canada, M5S 1A8
| | - Jun Parkes
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, M5T 1R8
| | - Junchao Tong
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, M5T 1R8
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, M5T 1R8
| | - Neil Vasdev
- Department of Radiology, Harvard Medical School and Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA, 02114
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada, M5T 1R8; Institute of Medical Science, University of Toronto, Toronto, ON, Canada, M5S 1A8.
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15
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Holland JP, Liang SH, Rotstein BH, Collier TL, Stephenson NA, Greguric I, Vasdev N. Alternative approaches for PET radiotracer development in Alzheimer's disease: imaging beyond plaque. J Labelled Comp Radiopharm 2013; 57:323-31. [PMID: 24327420 DOI: 10.1002/jlcr.3158] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/29/2013] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) and related dementias show increasing clinical prevalence, yet our understanding of the etiology and pathobiology of disease-related neurodegeneration remains limited. In this regard, noninvasive imaging with radiotracers for positron emission tomography (PET) presents a unique tool for quantifying spatial and temporal changes in characteristic biological markers of brain disease and for assessing potential drug efficacy. PET radiotracers targeting different protein markers are being developed to address questions pertaining to the molecular and/or genetic heterogeneity of AD and related dementias. For example, radiotracers including [(11) C]-PiB and [(18) F]-AV-45 (Florbetapir) are being used to measure the density of Aβ-plaques in AD patients and to interrogate the biological mechanisms of disease initiation and progression. Our focus is on the development of novel PET imaging agents, targeting proteins beyond Aβ-plaques, which can be used to investigate the broader mechanism of AD pathogenesis. Here, we present the chemical basis of various radiotracers which show promise in preclinical or clinical studies for use in evaluating the phenotypic or biochemical characteristics of AD. Radiotracers for PET imaging neuroinflammation, metal ion association with Aβ-plaques, tau protein, cholinergic and cannabinoid receptors, and enzymes including glycogen-synthase kinase-3β and monoamine oxidase B amongst others, and their connection to AD are highlighted.
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Affiliation(s)
- Jason P Holland
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Department of Radiology, Harvard Medical School, 55 Fruit St., White 427, Boston, Massachusetts, 02114, USA; Life Sciences, Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales, 2232, Australia
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16
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Rotstein BH, Liang SH, Holland JP, Collier TL, Hooker JM, Wilson AA, Vasdev N. 11CO2 fixation: a renaissance in PET radiochemistry. Chem Commun (Camb) 2013; 49:5621-9. [PMID: 23673726 PMCID: PMC5604310 DOI: 10.1039/c3cc42236d] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Carbon-11 labelled carbon dioxide is the cyclotron-generated feedstock reagent for most positron emission tomography (PET) tracers using this radionuclide. Most carbon-11 labels, however, are installed using derivative reagents generated from [(11)C]CO2. In recent years, [(11)C]CO2 has seen a revival in applications for the direct incorporation of carbon-11 into functional groups such as ureas, carbamates, oxazolidinones, carboxylic acids, esters, and amides. This review summarizes classical [(11)C]CO2 fixation strategies using organometallic reagents and then focuses on newly developed methods that employ strong organic bases to reversibly capture [(11)C]CO2 into solution, thereby enabling highly functionalized labelled compounds to be prepared. Labelled compounds and radiopharmaceuticals that have been translated to the clinic are highlighted.
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Affiliation(s)
- Benjamin H Rotstein
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
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17
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Liu P, Hamill TG, Chioda M, Chobanian H, Fung S, Guo Y, Chang L, Bakshi R, Hong Q, Dellureficio J, Lin LS, Abbadie C, Alexander J, Jin H, Mandala S, Shiao LL, Li W, Sanabria S, Williams D, Zeng Z, Hajdu R, Jochnowitz N, Rosenbach M, Karanam B, Madeira M, Salituro G, Powell J, Xu L, Terebetski JL, Leone JF, Miller P, Cook J, Holahan M, Joshi A, O’Malley S, Purcell M, Posavec D, Chen TB, Riffel K, Williams M, Hargreaves R, Sullivan KA, Nargund RP, DeVita RJ. Discovery of MK-3168: A PET Tracer for Imaging Brain Fatty Acid Amide Hydrolase. ACS Med Chem Lett 2013; 4:509-13. [PMID: 24900701 DOI: 10.1021/ml4000996] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/20/2013] [Indexed: 11/29/2022] Open
Abstract
We report herein the discovery of a fatty acid amide hydrolase (FAAH) positron emission tomography (PET) tracer. Starting from a pyrazole lead, medicinal chemistry efforts directed toward reducing lipophilicity led to the synthesis of a series of imidazole analogues. Compound 6 was chosen for further profiling due to its appropriate physical chemical properties and excellent FAAH inhibition potency across species. [(11)C]-6 (MK-3168) exhibited good brain uptake and FAAH-specific signal in rhesus monkeys and is a suitable PET tracer for imaging FAAH in the brain.
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Affiliation(s)
| | - Terence G. Hamill
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Wenping Li
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Sandra Sanabria
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - David Williams
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Zhizhen Zeng
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | | | | | | | | | | | | | | | | | | | | | - Patricia Miller
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Jacquelynn Cook
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Marie Holahan
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Aniket Joshi
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Stacey O’Malley
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Mona Purcell
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Diane Posavec
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Tsing-Bau Chen
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Kerry Riffel
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Mangay Williams
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
| | - Richard Hargreaves
- Department of Imaging Research, Merck Research Laboratories, West Point, Pennsylvania
19486, United States
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18
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Hicks JW, Parkes J, Sadovski O, Tong J, Houle S, Vasdev N, Wilson AA. Synthesis and preclinical evaluation of [11C-carbonyl]PF-04457845 for neuroimaging of fatty acid amide hydrolase. Nucl Med Biol 2013; 40:740-6. [PMID: 23731552 DOI: 10.1016/j.nucmedbio.2013.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/09/2013] [Accepted: 04/17/2013] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Fatty acid amide hydrolase (FAAH) has a significant role in regulating endocannabinoid signaling in the central nervous system. As such, FAAH inhibitors are being actively sought for pain, addiction, and other indications. This has led to the recent pursuit of positron emission tomography (PET) radiotracers targeting FAAH. We report herein the preparation and preclinical evaluation of [(11)C-carbonyl]PF-04457845, an isotopologue of the potent irreversible FAAH inhibitor. METHODS PF-04457845 was radiolabeled at the carbonyl position via automated [(11)C]CO(2)-fixation. Ex vivo brain biodistribution of [(11)C-carbonyl]PF-04457845 was carried out in conscious rats. Specificity was determined by pre-administration of PF-04457845 or URB597 prior to [(11)C-carbonyl]PF-04457845. In a separate experiment, rats injected with the title radiotracer had whole brains excised, homogenized and extracted to examine irreversible binding to brain parenchyma. RESULTS The title compound was prepared in 5 ± 1% (n = 4) isolated radiochemical yield based on starting [(11)C]CO(2) (decay uncorrected) within 25 min from end-of-bombardment in >98% radiochemical purity and a specific activity of 73.5 ± 8.2 GBq/μmol at end-of-synthesis. Uptake of [(11)C-carbonyl]PF-04457845 into the rat brain was high (range of 1.2-4.4 SUV), heterogeneous, and in accordance with reported FAAH distribution. Saturable binding was demonstrated by a dose-dependent reduction in brain radioactivity uptake following pre-treatment with PF-04457845. Pre-treatment with the prototypical FAAH inhibitor, URB597, reduced the brain radiotracer uptake in all regions by 71-81%, demonstrating specificity for FAAH. The binding of [(11)C-carbonyl]PF-04457845 to FAAH at 40 min post injection was irreversible as 98% of the radioactivity in the brain could not be extracted. CONCLUSIONS [(11)C-carbonyl]PF-04457845 was rapidly synthesized via an automated radiosynthesis. Ex vivo biodistribution studies in conscious rodents demonstrate that [11C PF-04457845 is a promising candidate radiotracer for imaging FAAH in the brain with PET. These results coupled with the known pharmacology and toxicology of PF-04457845 should facilitate clinical translation of this radiotracer.
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Affiliation(s)
- Justin W Hicks
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
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19
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Development and characterization of a promising fluorine-18 labelled radiopharmaceutical for in vivo imaging of fatty acid amide hydrolase. Bioorg Med Chem 2013; 21:4351-7. [PMID: 23712084 DOI: 10.1016/j.bmc.2013.04.077] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/15/2013] [Accepted: 04/22/2013] [Indexed: 01/05/2023]
Abstract
Fatty acid amide hydrolase (FAAH), the enzyme responsible for terminating signaling by the endocannabinoid anandamide, plays an important role in the endocannabinoid system, and FAAH inhibitors are attractive drugs for pain, addiction, and neurological disorders. The synthesis, radiosynthesis, and evaluation, in vitro and ex vivo in rat, of an (18)F-radiotracer designed to image FAAH using positron emission tomography (PET) is described. Fluorine-18 labelled 3-(4,5-dihydrooxazol-2-yl)phenyl (5-fluoropentyl)carbamate, [(18)F]5, was synthesized at high specific activity in a one-pot three step reaction using a commercial module with a radiochemical yield of 17-22% (from [(18)F]fluoride). In vitro assay using rat brain homogenates showed that 5 inhibited FAAH in a time-dependent manner, with an IC50 value of 0.82nM after a preincubation of 60min. Ex vivo biodistribution studies and ex vivo autoradiography in rat brain demonstrated that [(18)F]5 had high brain penetration with standard uptake values of up to 4.6 and had a regional distribution which correlated with reported regional FAAH enzyme activity. Specificity of binding to FAAH with [(18)F]5 was high (>90%) as demonstrated by pharmacological challenges with potent and selective FAAH inhibitors and was irreversible as demonstrated by radioactivity measurements on homogenized brain tissue extracts. We infer from these results that [(18)F]5 is a highly promising candidate radiotracer with which to image FAAH in human subjects using PET and clinical studies are proceeding.
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21
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Holland JP, Cumming P, Vasdev N. PET radiopharmaceuticals for probing enzymes in the brain. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2013; 3:194-216. [PMID: 23638333 PMCID: PMC3627518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 03/07/2013] [Indexed: 06/02/2023]
Abstract
Biologically important processes in normal brain function and brain disease involve the action of various protein-based receptors, ion channels, transporters and enzymes. The ability to interrogate the location, abundance and activity of these entities in vivo using non-invasive molecular imaging can provide unprecedented information about the spatio-temporal dynamics of brain function. Indeed, positron emission tomography (PET) imaging is transforming our understanding of the central nervous system and brain disease. Great emphasis has historically been placed on developing radioligands for the non-invasive detection of neuroreceptors. In contrast, relatively few enzymes have been amenable to examination by PET imaging procedures based upon trapping or accumulation of enzymatic products, because only a subset of enzymes have sufficient catalytic rate to produce measureable accumulation within the practical time-limit of PET recordings. However, high affinity inhibitors are now serving as tracers for enzymes, particularly for measuring the abundance of enzymes mediating intracellular signal transduction in the brain, which offer a rich diversity of potential targets for drug discovery. The purpose of this review is to summarize well-known radiotracers for brain enzymes, and draw attention to recent developments in PET radiotracers for imaging signal transduction pathways in the brain. The review is organized by target class and focuses on structural chemistry of the best-established radiotracers identified in each class.
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Affiliation(s)
- Jason P Holland
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School55 Fruit St., White 427, Boston, MA 02114, USA
| | - Paul Cumming
- Department of Nuclear Medicine, Universitätsklinikum ErlangenUlmenweg 18, Erlangen, Germany, 91054
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School55 Fruit St., White 427, Boston, MA 02114, USA
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Model-based drug development: a rational approach to efficiently accelerate drug development. Clin Pharmacol Ther 2013; 93:502-14. [PMID: 23588322 DOI: 10.1038/clpt.2013.54] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The pharmaceutical industry continues to face significant challenges. Very few compounds that enter development reach the marketplace, and the investment required for each success can surpass $1.8 billion. Despite attempts to improve efficiency and increase productivity, total investment continues to rise whereas the output of new medicines declines. With costs increasing exponentially through each development phase, it is failure in phase II and phase III that is most wasteful. In today's development paradigm, late-stage failure is principally a result of insufficient efficacy. This is manifested as either a failure to differentiate sufficiently from placebo (shown for both novel and precedented mechanisms) or a failure to demonstrate sufficient differentiation from existing compounds. Set in this context, this article will discuss the role model-based drug development (MBDD) approaches can and do play in accelerating and optimizing compound development strategies through a series of illustrative examples.
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23
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Wilson AA, Hicks JW, Sadovski O, Parkes J, Tong J, Houle S, Fowler CJ, Vasdev N. Radiosynthesis and evaluation of [¹¹C-carbonyl]-labeled carbamates as fatty acid amide hydrolase radiotracers for positron emission tomography. J Med Chem 2012; 56:201-9. [PMID: 23214511 PMCID: PMC3544278 DOI: 10.1021/jm301492y] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Fatty acid amide hydrolase (FAAH) plays a key role in
regulating
the tone of the endocannabinoid system. Radiotracers are required
to image and quantify FAAH activity in vivo. We have synthesized a
series of potent FAAH inhibitors encompassing two classes of N-alkyl-O-arylcarbamates and radiolabeled
eight of them with carbon-11. The [11C-carbonyl]-radiotracers were evaluated in vitro and ex vivo in rats as potential
FAAH imaging agents for positron emission tomography (PET). Both sets
of [11C]O-arylcarbamates showed good to
excellent brain penetration and an appropriate regional distribution.
Pretreatments with a FAAH inhibitor demonstrated that 80–95%
of brain uptake of radioactivity constituted binding of the radiotracers
to FAAH. Brain extraction measurements showed that binding to FAAH
was irreversible and kinetically different for the two classes of
carbamates. These promising results are discussed in terms of the
requirements of a suitable radiotracer for the in vivo imaging of
FAAH using PET.
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Affiliation(s)
- Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
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