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Mei H, Han J, White S, Graham DJ, Izawa K, Sato T, Fustero S, Meanwell NA, Soloshonok VA. Tailor-Made Amino Acids and Fluorinated Motifs as Prominent Traits in Modern Pharmaceuticals. Chemistry 2020; 26:11349-11390. [PMID: 32359086 DOI: 10.1002/chem.202000617] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/23/2020] [Indexed: 12/11/2022]
Abstract
Structural analysis of modern pharmaceutical practices allows for the identification of two rapidly growing trends: the introduction of tailor-made amino acids and the exploitation of fluorinated motifs. Curiously, the former represents one of the most ubiquitous classes of naturally occurring compounds, whereas the latter is the most xenobiotic and comprised virtually entirely of man-made derivatives. Herein, 39 selected compounds, featuring both of these traits in the same molecule, are profiled. The total synthesis, source of the corresponding amino acids and fluorinated residues, and medicinal chemistry aspects and biological properties of the molecules are discussed.
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Affiliation(s)
- Haibo Mei
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, P.R. China
| | - Jianlin Han
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, P.R. China
| | - Sarah White
- Oakwood Chemical, Inc., 730 Columbia Hwy. N, Estill, SC, 29918, USA
| | - Daniel J Graham
- Oakwood Chemical, Inc., 730 Columbia Hwy. N, Estill, SC, 29918, USA
| | - Kunisuke Izawa
- Hamari Chemicals Ltd., 1-4-29 Kunijima, Higashi-Yodogawa-ku, Osaka, 533-0024, Japan
| | - Tatsunori Sato
- Hamari Chemicals Ltd., 1-4-29 Kunijima, Higashi-Yodogawa-ku, Osaka, 533-0024, Japan
| | - Santos Fustero
- Departamento de Química Orgánica, Universidad de Valencia, 46100, Burjassot, Valencia, Spain
| | - Nicholas A Meanwell
- Department of Small Molecule Drug Discovery, Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, NJ, 08543-4000, USA
| | - Vadim A Soloshonok
- Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018, San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, María Díaz de Haro 3, Plaza Bizkaia, 48013, Bilbao, Spain
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52
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Zheng QH. Radioligands targeting purinergic P2X7 receptor. Bioorg Med Chem Lett 2020; 30:127169. [DOI: 10.1016/j.bmcl.2020.127169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 12/12/2022]
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Berdyyeva T, Xia C, Taylor N, He Y, Chen G, Huang C, Zhang W, Kolb H, Letavic M, Bhattacharya A, Szardenings AK. PET Imaging of the P2X7 Ion Channel with a Novel Tracer [ 18F]JNJ-64413739 in a Rat Model of Neuroinflammation. Mol Imaging Biol 2020; 21:871-878. [PMID: 30632003 DOI: 10.1007/s11307-018-01313-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE The P2X7 receptor, an adenosine triphosphate (ATP)-gated purinoreceptor, has emerged as one of the key players in neuroinflammatory processes. Therefore, developing a positron emission tomography (PET) tracer for imaging of P2X7 receptors in vivo presents a promising approach to diagnose, monitor, and study neuroinflammation in a variety of brain disorders. To fulfill the goal of developing a P2X7 PET ligand as a biomarker of neuroinflammation, [18F]JNJ-64413739 has been recently disclosed. PROCEDURES We evaluated [18F]JNJ-64413739 in a rat model of neuroinflammation induced by an intracerebral injection of lipopolysaccharide (LPS). In vivo brain uptake was determined by PET imaging. Upregulation of neuroinflammatory biomarkers was determined by quantitative polymerase chain reaction (qPCR). Distribution of the tracer in the brain was determined by ex vivo autoradiography (ARG). The specificity of [18F]JNJ-64413739 was confirmed by performing blocking experiments with the P2X7 antagonist JNJ-54175446. RESULTS Brain regions of rats injected with LPS had a significantly increased uptake (34 % ± 3 % s.e.m., p = 0.036, t test, standardized uptake value measured over the entire scanning period) of [18F]JNJ-64413739 relative to the corresponding brain regions of control animals injected with phosphate-buffered saline (PBS). The uptake in the contralateral regions and cerebellum was not significantly different between the groups of animals. The increase in uptake of [18F]JNJ-64413739 at the LPS-injected site observed by PET imaging was concordant with ex vivo ARG, upregulation of neuroinflammatory biomarkers, and elevated P2X7 expression levels. CONCLUSIONS While further work is needed to study [18F]JNJ-64413739 in other types of neuroinflammation, the current results favorably characterize [18F]JNJ-64413739 as a potential PET tracer of central neuroinflammation.
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Affiliation(s)
- Tamara Berdyyeva
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA.
| | - Chunfang Xia
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Natalie Taylor
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Yingbo He
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Gang Chen
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Chaofeng Huang
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Wei Zhang
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Hartmuth Kolb
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Michael Letavic
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Anindya Bhattacharya
- Janssen Research & Development LLC, 3210 Merryfield Row, San Diego, CA, 92121, USA
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Hampel H, Caraci F, Cuello AC, Caruso G, Nisticò R, Corbo M, Baldacci F, Toschi N, Garaci F, Chiesa PA, Verdooner SR, Akman-Anderson L, Hernández F, Ávila J, Emanuele E, Valenzuela PL, Lucía A, Watling M, Imbimbo BP, Vergallo A, Lista S. A Path Toward Precision Medicine for Neuroinflammatory Mechanisms in Alzheimer's Disease. Front Immunol 2020; 11:456. [PMID: 32296418 PMCID: PMC7137904 DOI: 10.3389/fimmu.2020.00456] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 02/27/2020] [Indexed: 12/13/2022] Open
Abstract
Neuroinflammation commences decades before Alzheimer's disease (AD) clinical onset and represents one of the earliest pathomechanistic alterations throughout the AD continuum. Large-scale genome-wide association studies point out several genetic variants—TREM2, CD33, PILRA, CR1, MS4A, CLU, ABCA7, EPHA1, and HLA-DRB5-HLA-DRB1—potentially linked to neuroinflammation. Most of these genes are involved in proinflammatory intracellular signaling, cytokines/interleukins/cell turnover, synaptic activity, lipid metabolism, and vesicle trafficking. Proteomic studies indicate that a plethora of interconnected aberrant molecular pathways, set off and perpetuated by TNF-α, TGF-β, IL-1β, and the receptor protein TREM2, are involved in neuroinflammation. Microglia and astrocytes are key cellular drivers and regulators of neuroinflammation. Under physiological conditions, they are important for neurotransmission and synaptic homeostasis. In AD, there is a turning point throughout its pathophysiological evolution where glial cells sustain an overexpressed inflammatory response that synergizes with amyloid-β and tau accumulation, and drives synaptotoxicity and neurodegeneration in a self-reinforcing manner. Despite a strong therapeutic rationale, previous clinical trials investigating compounds with anti-inflammatory properties, including non-steroidal anti-inflammatory drugs (NSAIDs), did not achieve primary efficacy endpoints. It is conceivable that study design issues, including the lack of diagnostic accuracy and biomarkers for target population identification and proof of mechanism, may partially explain the negative outcomes. However, a recent meta-analysis indicates a potential biological effect of NSAIDs. In this regard, candidate fluid biomarkers of neuroinflammation are under analytical/clinical validation, i.e., TREM2, IL-1β, MCP-1, IL-6, TNF-α receptor complexes, TGF-β, and YKL-40. PET radio-ligands are investigated to accomplish in vivo and longitudinal regional exploration of neuroinflammation. Biomarkers tracking different molecular pathways (body fluid matrixes) along with brain neuroinflammatory endophenotypes (neuroimaging markers), can untangle temporal–spatial dynamics between neuroinflammation and other AD pathophysiological mechanisms. Robust biomarker–drug codevelopment pipelines are expected to enrich large-scale clinical trials testing new-generation compounds active, directly or indirectly, on neuroinflammatory targets and displaying putative disease-modifying effects: novel NSAIDs, AL002 (anti-TREM2 antibody), anti-Aβ protofibrils (BAN2401), and AL003 (anti-CD33 antibody). As a next step, taking advantage of breakthrough and multimodal techniques coupled with a systems biology approach is the path to pursue for developing individualized therapeutic strategies targeting neuroinflammation under the framework of precision medicine.
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Affiliation(s)
- Harald Hampel
- Sorbonne University, GRC no. 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'hôpital, Paris, France
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute-IRCCS, Troina, Italy
| | - A Claudio Cuello
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada.,Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | | | - Robert Nisticò
- Laboratory of Neuropharmacology, EBRI Rita Levi-Montalcini Foundation, Rome, Italy.,School of Pharmacy, Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Massimo Corbo
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
| | - Filippo Baldacci
- Sorbonne University, GRC no. 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'hôpital, Paris, France.,Brain & Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'hôpital, Paris, France.,Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.,Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Nicola Toschi
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.,Department of Radiology, "Athinoula A. Martinos" Center for Biomedical Imaging, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States
| | - Francesco Garaci
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.,Casa di Cura "San Raffaele Cassino", Cassino, Italy
| | - Patrizia A Chiesa
- Sorbonne University, GRC no. 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'hôpital, Paris, France.,Brain & Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'hôpital, Paris, France.,Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
| | | | | | - Félix Hernández
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Jesús Ávila
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | | | | | - Alejandro Lucía
- Faculty of Sport Sciences, Universidad Europea de Madrid, Madrid, Spain.,Research Institute of the Hospital 12 de Octubre ("imas"), Madrid, Spain.,Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | | | - Bruno P Imbimbo
- Research & Development Department, Chiesi Farmaceutici, Parma, Italy
| | - Andrea Vergallo
- Sorbonne University, GRC no. 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'hôpital, Paris, France
| | - Simone Lista
- Sorbonne University, GRC no. 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'hôpital, Paris, France.,Brain & Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'hôpital, Paris, France.,Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, Pitié-Salpêtrière Hospital, AP-HP, Paris, France
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Hupp S, Iliev AI. CSF-1 receptor inhibition as a highly effective tool for depletion of microglia in mixed glial cultures. J Neurosci Methods 2020; 332:108537. [PMID: 31790710 DOI: 10.1016/j.jneumeth.2019.108537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/26/2019] [Accepted: 11/28/2019] [Indexed: 11/15/2022]
Abstract
BACKGROUND A breakthrough in the microglia and macrophages field was the identification of the macrophage colony stimulating factor-1 (CSF-1) as a pro-survival factor. Its pharmacological inhibition in animals depletes rapidly all microglia and macrophages. Microglial depletion in mixed glial cultures has always represented a challenge and none of the existing approaches delivers satisfactory results. NEW METHOD We applied a CSF-1R inhibitor (PLX5622) in primary mouse glial cultures, analyzing microglial dose-responses, starting at different time-points and incubating for various periods of time. RESULTS We used two treatment modalities with 10 μM PLX5622 to deplete microglia: i) immediately after brain homogenization and ii) at day in vitro 12. The application of the inhibitor immediately after cell preparation depleted microglia to 8% at 1 week, to 2% at 4 weeks and to 0.5% at 6 weeks (half-time 3.5 days). When mixed glial cultures were treated starting at day in vitro 12, microglia depletion was slower (half-time 6 days) and not complete, indicating a decreased sensitivity to CSF-1. The remaining astrocytes preserved their proliferation ability, their migration in a scratch wound assay, and their pro-inflammatory (IL-6) response towards lipopolysaccharide. COMPARISON TO EXISTING METHODS The proposed approach for microglial depletion in mixed glial cultures is more effective than other existing methods and is non-toxic to non-microglial cells. CONCLUSIONS CSF-1R inhibitors are effective tools for depleting microglia in mixed glial cultures. Longer maturation of the cultures leads to a diminished sensitivity of microglia towards CSF-1. Thus, the treatment should start as early as possible after glial culture preparation.
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Affiliation(s)
- Sabrina Hupp
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland.
| | - Asparouh I Iliev
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland.
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56
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Abstract
This review discusses nuclear imaging of inflammation using molecular probes beyond fluoro-d-glucose, is structured by cellular targets, and focuses on those tracers that have been successfully applied clinically.
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Affiliation(s)
- Malte Kircher
- Department of Nuclear Medicine, University Hospital Augsburg, Stenglinstr. 2, Würzburg 86156, Germany
| | - Constantin Lapa
- Department of Nuclear Medicine, University Hospital Augsburg, Stenglinstr. 2, Würzburg 86156, Germany.
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57
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McCluskey SP, Plisson C, Rabiner EA, Howes O. Advances in CNS PET: the state-of-the-art for new imaging targets for pathophysiology and drug development. Eur J Nucl Med Mol Imaging 2020; 47:451-489. [PMID: 31541283 PMCID: PMC6974496 DOI: 10.1007/s00259-019-04488-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE A limit on developing new treatments for a number of central nervous system (CNS) disorders has been the inadequate understanding of the in vivo pathophysiology underlying neurological and psychiatric disorders and the lack of in vivo tools to determine brain penetrance, target engagement, and relevant molecular activity of novel drugs. Molecular neuroimaging provides the tools to address this. This article aims to provide a state-of-the-art review of new PET tracers for CNS targets, focusing on developments in the last 5 years for targets recently available for in-human imaging. METHODS We provide an overview of the criteria used to evaluate PET tracers. We then used the National Institute of Mental Health Research Priorities list to identify the key CNS targets. We conducted a PubMed search (search period 1st of January 2013 to 31st of December 2018), which yielded 40 new PET tracers across 16 CNS targets which met our selectivity criteria. For each tracer, we summarised the evidence of its properties and potential for use in studies of CNS pathophysiology and drug evaluation, including its target selectivity and affinity, inter and intra-subject variability, and pharmacokinetic parameters. We also consider its potential limitations and missing characterisation data, but not specific applications in drug development. Where multiple tracers were present for a target, we provide a comparison of their properties. RESULTS AND CONCLUSIONS Our review shows that multiple new tracers have been developed for proteinopathy targets, particularly tau, as well as the purinoceptor P2X7, phosphodiesterase enzyme PDE10A, and synaptic vesicle glycoprotein 2A (SV2A), amongst others. Some of the most promising of these include 18F-MK-6240 for tau imaging, 11C-UCB-J for imaging SV2A, 11C-CURB and 11C-MK-3168 for characterisation of fatty acid amide hydrolase, 18F-FIMX for metabotropic glutamate receptor 1, and 18F-MNI-444 for imaging adenosine 2A. Our review also identifies recurrent issues within the field. Many of the tracers discussed lack in vivo blocking data, reducing confidence in selectivity. Additionally, late-stage identification of substantial off-target sites for multiple tracers highlights incomplete pre-clinical characterisation prior to translation, as well as human disease state studies carried out without confirmation of test-retest reproducibility.
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Affiliation(s)
- Stuart P McCluskey
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Christophe Plisson
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Oliver Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
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58
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Li M, Luo S, Zhang Y, Jia L, Yang C, Peng X, Zhao R. Production, characterization, and application of a monoclonal antibody specific for the extracellular domain of human P2X7R. Appl Microbiol Biotechnol 2020; 104:2017-2028. [PMID: 31930453 DOI: 10.1007/s00253-019-10340-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/14/2019] [Accepted: 12/27/2019] [Indexed: 12/17/2022]
Abstract
This paper focuses on the production of a high-affinity monoclonal antibody (mAb) that can efficiently detect and block purinergic ligand-gated ion channel 7 receptor (P2X7R). To achieve this goal, the extracellular domain of human P2X7R, P2X7R-ECD, was used as an immunogen for BALB/c mice, inducing them to produce spleen lymphocytes that were subsequently fused with myeloma cells. Screening of the resultant hybridoma clones resulted in the selection of one stable positive clone that produced a qualified mAb, named 4B3A4. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that the purity of the purified 4B3A4 mAb was above 85%, with prominent bands corresponding to molecular weights of 55 kDa (heavy chain) and 25 kDa (light chain), and the BCA assay showed that the concentration of the purified 4B3A4 mAb was 0.3 mg/mL. Western blot analysis revealed that the 4B3A4 mAb could specifically recognize and bind both P2X7R-ECD and the full-length P2X7R protein. Laser scanning confocal microscopy (LSCM) revealed that the 4B3A4 mAb specifically bound to P2X7R on the membrane of human peripheral blood mononuclear cells (PBMCs). P2X7R expression was significantly different between healthy individuals and people with certain cancers as determined by flow cytometry (FCM). In addition, the 4B3A4 mAb significantly reduced ATP-stimulated Ca2+ entry and YO-PRO-1 uptake, which indicated that the 4B3A4 mAb effectively blocked P2X7R activity. These data indicate that the 4B3A4 mAb can be further used as not only an antibody to detect cell surface P2X7R but also as a therapeutic antibody to target P2X7R-related signaling pathways.
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Affiliation(s)
- Mingxuan Li
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Shuping Luo
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Yunfang Zhang
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Lina Jia
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Chuanyu Yang
- Department of Blood Transfusion, Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China
| | - Xiaoxiang Peng
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China
| | - Ronglan Zhao
- Department of Laboratory Medicine, Weifang Medical University, Weifang, Shandong, China.
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Kubota K, Ogawa M, Ji B, Watabe T, Zhang MR, Suzuki H, Sawada M, Nishi K, Kudo T. Basic Science of PET Imaging for Inflammatory Diseases. PET/CT FOR INFLAMMATORY DISEASES 2020. [PMCID: PMC7418531 DOI: 10.1007/978-981-15-0810-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
FDG-PET/CT has recently emerged as a useful tool for the evaluation of inflammatory diseases too, in addition to that of malignant diseases. The imaging is based on active glucose utilization by inflammatory tissue. Autoradiography studies have demonstrated high FDG uptake in macrophages, granulocytes, fibroblasts, and granulation tissue. Especially, activated macrophages are responsible for the elevated FDG uptake in some types of inflammation. According to one study, after activation by lipopolysaccharide of cultured macrophages, the [14C]2DG uptake by the cells doubled, reaching the level seen in glioblastoma cells. In activated macrophages, increase in the expression of total GLUT1 and redistributions from the intracellular compartments toward the cell surface have been reported. In one rheumatoid arthritis model, following stimulation by hypoxia or TNF-α, the highest elevation of the [3H]FDG uptake was observed in the fibroblasts, followed by that in macrophages and neutrophils. As the fundamental mechanism of elevated glucose uptake in both cancer cells and inflammatory cells, activation of glucose metabolism as an adaptive response to a hypoxic environment has been reported, with transcription factor HIF-1α playing a key role. Inflammatory cells and cancer cells seem to share the same molecular mechanism of elevated glucose metabolism, lending support to the notion of usefulness of FDGPET/CT for the evaluation of inflammatory diseases, besides cancer.
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60
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Aurelian L, Balan I. GABA AR α2-activated neuroimmune signal controls binge drinking and impulsivity through regulation of the CCL2/CX3CL1 balance. Psychopharmacology (Berl) 2019; 236:3023-3043. [PMID: 31030249 DOI: 10.1007/s00213-019-05220-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/04/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND PURPOSE Toll-like receptors (TLRs) are a family of innate immune system receptors that respond to pathogen-derived and tissue damage-related ligands and are increasingly recognized for their impact on homeostasis and its dysregulation in the nervous system. TLR signaling participates in brain injury and addiction, but its role in the alcohol-seeking behavior, which initiates alcohol drinking, is still poorly understood. In this review, we discuss our findings designed to elucidate the potential contribution of the activated TLR4 signal located in neurons, on impulsivity and the predisposition to initiate alcohol drinking (binge drinking). RESULTS Our findings indicate that the TLR4 signal is innately activated in neurons from alcohol-preferring subjects, identifying a genetic contribution to the regulation of impulsivity and the alcohol-seeking propensity. Signal activation is through the non-canonical, previously unknown, binding of TLR4 to the α2 subunit of the γ-aminobutyric 2 acid A receptor (GABAAR α2). Activation is sustained by the stress hormone corticotrophin-releasing factor (CRF) and additional still poorly recognized ligand/scaffold proteins. Focus is on the effect of TLR4 signal activation on the balance between pro- and anti-inflammatory chemokines [chemokine (C-C motif) ligand 2 (CCL2)/chemokine (C-X3-C motif) ligand 1 (CX3CL1)] and its effect on binge drinking. CONCLUSION The results are discussed within the context of current findings on the distinct activation and functions of TLR signals located in neurons, as opposed to immune cells. They indicate that the balance between pro- and anti-inflammatory TLR4 signaling plays a major role in binge drinking. These findings have major impact on future basic and translational research, including the development of potential therapeutic and preventative strategies.
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Affiliation(s)
- Laure Aurelian
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Stanford University School of Medicine OFDD, Stanford, CA, 94305, USA.
| | - Irina Balan
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Van Weehaeghe D, Koole M, Schmidt ME, Deman S, Jacobs AH, Souche E, Serdons K, Sunaert S, Bormans G, Vandenberghe W, Van Laere K. [ 11C]JNJ54173717, a novel P2X7 receptor radioligand as marker for neuroinflammation: human biodistribution, dosimetry, brain kinetic modelling and quantification of brain P2X7 receptors in patients with Parkinson's disease and healthy volunteers. Eur J Nucl Med Mol Imaging 2019; 46:2051-2064. [PMID: 31243495 DOI: 10.1007/s00259-019-04369-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/23/2019] [Indexed: 01/11/2023]
Abstract
PURPOSE The P2X7 receptor (P2X7R) is an ATP-gated ion channel predominantly expressed on activated microglia and is important in neurodegenerative diseases including Parkinson's disease (PD). In this first-in-human study, we investigated [11C]JNJ54173717 ([11C]JNJ717), a selective P2X7R tracer, in healthy volunteers (HV) and PD patients. Biodistribution, dosimetry, kinetic modelling and short-term test-retest variation (TRV), as well as possible genotype effects, were investigated. METHODS Biodistribution and radiation dosimetry studies were performed in three HV (mean age 30 ± 2 years, two women) using whole-body PET/CT. The most appropriate kinetic model was determined in 11 HV (mean age 62 ± 10 years, six women) and 10 PD patients (mean age 64 ± 8 years, three women; mean UPDRS motor score 21 ± 8) using 90-min dynamic simultaneous PET/MR scans. The total volume of distribution (VT) was calculated using a one-tissue and a two-tissue compartment model (1TCM, 2TCM) and Logan graphical analysis, and its time stability was assessed. Seven subjects underwent retest scans (mean age 60 ± 13 years, four HV, one woman). A group analysis was performed to compare PD patients and HV. Finally, 13 exons of P2X7R were genotyped in all subjects included in the second part of the study. RESULTS The mean effective dose was 4.47 ± 0.32 μSv/MBq, with the highest absorbed doses to the gallbladder, liver and small intestine. A reversible 2TCM was the most appropriate kinetic model with relatively homogeneous VT values in the grey and white matter. Average VT values were 3.4 ± 0.8 in HV and 3.3 ± 0.7 in PD patients, with no significant difference between the groups, but a possible genotype effect (rs3751143) was identified which can affect VT. Average TRV was 10-15%. The stability of VT over time allowed a reduction in scan time to 70 min. CONCLUSION [11C]JNJ717 is safe and suitable for quantifying P2X7R expression in human brain. In this pilot study, no significant differences in P2X7R binding were found between HV and PD patients. The results also suggest that genotype effects need to be incorporated in future P2X7R PET analyses.
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Affiliation(s)
- Donatienne Van Weehaeghe
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals of Leuven and KU Leuven, Leuven, Belgium.
| | - Michel Koole
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals of Leuven and KU Leuven, Leuven, Belgium
| | - Mark E Schmidt
- Janssen Research and Development: Beerse, Beerse, Belgium
| | - Stephanie Deman
- Genomics Core, UZ Leuven, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfalian Wilhelms University (WWU) Münster, Münster, Germany
- Department of Geriatrics and Neurology, Johanniter Hospital Bonn, Bonn, Germany
| | - Erika Souche
- Genomics Core, UZ Leuven, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Kim Serdons
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals of Leuven and KU Leuven, Leuven, Belgium
| | - Stefan Sunaert
- Department of Radiology, University Hospitals Leuven, Gasthuisberg, UZ, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, KU Leuven, Leuven, Belgium
| | - Wim Vandenberghe
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Koen Van Laere
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals of Leuven and KU Leuven, Leuven, Belgium
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Crabbé M, Van der Perren A, Bollaerts I, Kounelis S, Baekelandt V, Bormans G, Casteels C, Moons L, Van Laere K. Increased P2X7 Receptor Binding Is Associated With Neuroinflammation in Acute but Not Chronic Rodent Models for Parkinson's Disease. Front Neurosci 2019; 13:799. [PMID: 31417352 PMCID: PMC6684733 DOI: 10.3389/fnins.2019.00799] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/17/2019] [Indexed: 12/26/2022] Open
Abstract
The purinergic P2X7 receptor is a key mediator in (neuro)inflammation, a process that is associated with neurodegeneration and excitotoxicity in Parkinson’s disease (PD). Recently, P2X7 imaging has become possible with [11C]JNJ-(54173)717. We investigated P2X7 availability, in comparison with availability of the translocator protein (TSPO), in two well-characterized rat models of PD using in vitro autoradiography at multiple time points throughout the disease progression. Rats received either a unilateral injection with 6-hydroxydopamine (6-OHDA) in the striatum, or with recombinant adeno-associated viral vector overexpressing human A53T alpha-synuclein (α-SYN) in the substantia nigra. Transverse cryosections were incubated with [11C]JNJ-717 for P2X7 or [18F]DPA-714 for TSPO. [11C]JNJ-717 binding ratios were transiently elevated in the striatum of 6-OHDA rats at day 14–28 post-injection, with peak P2X7 binding at day 14. This largely coincided with the time course of striatal [18F]DPA-714 binding which was elevated at day 7–21, with peak TSPO binding at day 7. Increased P2X7 availability co-localized with microglial, but not astrocyte or neuronal markers. In the chronic α-SYN model, no significant differences were found in P2X7 binding, although in vitro TSPO overexpression was reported previously. This first study showed an increased P2X7 availability in the acute PD model in a time window corresponding with elevated TSPO binding and motor behavior changes. In contrast, the dynamics of TSPO and P2X7 were divergent in the chronic α-SYN model where no P2X7 changes were detectable. Overall, extended P2X7 phenotyping is warranted prior to implementation of P2X7 imaging for monitoring of neuroinflammation.
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Affiliation(s)
- Melissa Crabbé
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital Leuven, KU Leuven, Leuven, Belgium.,Molecular Small Animal Imaging Center, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Anke Van der Perren
- Laboratory for Neurobiology and Gene therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Viral Vector Core, KU Leuven, Leuven, Belgium
| | - Ilse Bollaerts
- Laboratory of Neuronal Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium
| | - Savannah Kounelis
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital Leuven, KU Leuven, Leuven, Belgium.,Molecular Small Animal Imaging Center, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Viral Vector Core, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Molecular Small Animal Imaging Center, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium.,Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Cindy Casteels
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital Leuven, KU Leuven, Leuven, Belgium.,Molecular Small Animal Imaging Center, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neuronal Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, University Hospital Leuven, KU Leuven, Leuven, Belgium.,Molecular Small Animal Imaging Center, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
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63
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Gao M, Wang M, Meyer JA, Territo PR, Hutchins GD, Zarrinmayeh H, Zheng QH. Synthesis and in vitro biological evaluation of new P2X7R radioligands [11C]halo-GSK1482160 analogs. Bioorg Med Chem Lett 2019; 29:1476-1480. [DOI: 10.1016/j.bmcl.2019.04.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 02/07/2023]
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64
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Jia L, Miao C, Dong F, Li W, Wang M, Zheng QH, Xu Z. Facile synthesis of carbon-11-labeled sEH/PDE4 dual inhibitors as new potential PET agents for imaging of sEH/PDE4 enzymes in neuroinflammation. Bioorg Med Chem Lett 2019; 29:1654-1659. [PMID: 31047754 DOI: 10.1016/j.bmcl.2019.04.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/15/2019] [Accepted: 04/24/2019] [Indexed: 02/05/2023]
Abstract
To develop PET tracers for imaging of neuroinflammation, new carbon-11-labeled sEH/PDE4 dual inhibitors have been synthesized. The reference standard N-(4-methoxy-2-(trifluoromethyl)benzyl)benzamide (1) and its corresponding desmethylated precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)benzamide (2) were synthesized from (4-methoxy-2-(trifluoromethyl)phenyl)methanamine and benzoic acid in one and two steps with 84% and 49% overall chemical yield, respectively. The standard N-(4-methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (MPPA, 4) and its precursor N-(4-hydroxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide (5) were synthesized from methyl 4-piperidinecarboxylate, propionyl chloride and (4-methoxy-2-(trifluoromethyl)phenyl)methanamine in two and three steps with 62% and 34% overall chemical yield, respectively. The target tracers N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)benzamide ([11C]1) and N-(4-[11C]methoxy-2-(trifluoromethyl)benzyl)-1-propionylpiperidine-4-carboxamide ([11C]MPPA, [11C]4) were prepared from their corresponding precursors 2 and 5 with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 25-35% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (AM) at EOB was 370-740 GBq/μmol with a total synthesis time of 35-40-minutes from EOB.
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Affiliation(s)
- Limeng Jia
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Caihong Miao
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Fugui Dong
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Wei Li
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16(th) Street, Room 202, Indianapolis, IN 46202, USA
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16(th) Street, Room 202, Indianapolis, IN 46202, USA.
| | - Zhidong Xu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China; College of Chemical & Pharmaceutical Engineering, Key Laboratory of Molecular Chemistry for Medicine of Hebei Province, Hebei University of Science & Technology, Shijiazhuang, Hebei 050018, China; Shijiazhuang Vince Pharmatech Co., Ltd., Shijiazhuang, Hebei 050030, China.
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65
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Aiello M, Cavaliere C, Fiorenza D, Duggento A, Passamonti L, Toschi N. Neuroinflammation in Neurodegenerative Diseases: Current Multi-modal Imaging Studies and Future Opportunities for Hybrid PET/MRI. Neuroscience 2019; 403:125-135. [DOI: 10.1016/j.neuroscience.2018.07.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/28/2022]
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66
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Scarpellino G, Genova T, Munaron L. Purinergic P2X7 Receptor: A Cation Channel Sensitive to Tumor Microenvironment. Recent Pat Anticancer Drug Discov 2019; 14:32-38. [DOI: 10.2174/1574892814666190116122256] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/06/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023]
Abstract
Background: Purinergic signalling is involved in several physiological and pathophysiological processes. P2X7 Receptor (P2X7R) is a calcium-permeable ion channel that is gaining interest as a potential therapeutic target for the treatment of different diseases including inflammation, pain, psychiatric disorders and cancer. P2X7R is ubiquitously expressed and sensitive to high ATP levels, usually found in tumor microenvironment. P2X7R regulates several cell functions, from migration to cell death, but its selective contribution to tumor progression remains controversial.Objective:Current review was conducted to check involvement of P2X7R use in cancer treatment.Methods:We review the most recent patents focused on the use of P2X7R in the treatment of cancer.Results:P2X7R is an intriguing purinergic receptor that plays different roles in tumor progression.Conclusion:Powerful strategies able to selectively interfere with its expression and function should reveal helpful in the development of new anti-cancer therapies.
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Affiliation(s)
- Giorgia Scarpellino
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Tullio Genova
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Luca Munaron
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
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67
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Kolb HC, Barret O, Bhattacharya A, Chen G, Constantinescu C, Huang C, Letavic M, Tamagnan G, Xia CA, Zhang W, Szardenings AK. Preclinical Evaluation and Nonhuman Primate Receptor Occupancy Study of 18F-JNJ-64413739, a PET Radioligand for P2X7 Receptors. J Nucl Med 2019; 60:1154-1159. [PMID: 30733317 DOI: 10.2967/jnumed.118.212696] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 01/01/2019] [Indexed: 12/24/2022] Open
Abstract
The P2X7 receptor is an adenosine triphosphate-gated ion channel, which is abundantly expressed in glial cells within the central nervous system and in the periphery. P2X7 receptor activation leads to the release of the proinflammatory cytokine IL-1β in the brain, and antagonism of the P2X7 receptor is a novel therapeutic strategy to dampen adenosine triphosphate-dependent IL-1β signaling. PET ligands for the P2X7 receptor will not only be valuable to assess central target engagement of drug candidates but also hold promise as surrogate markers of central neuroinflammation. Herein we describe the in vitro and in vivo evaluation of 18F-JNJ-64413739, an 18F-labeled PET ligand for imaging the P2X7 receptor in the brain. Methods: P2X7 receptor affinity and specificity, pharmacokinetics, metabolic stability, blood-brain barrier permeability, and off-target binding of JNJ-64413739 were evaluated in a series of in vitro, ex vivo, and in vivo assays. 18F-JNJ-64413739 was radiolabeled via a one-step nucleophilic aromatic substitution. The tracer was also studied in rhesus macaques, and PET images were analyzed with an arterial plasma input function-based Logan graphical analysis. Results: The potency (half-maximal inhibitory concentration) of the P2X7 receptor antagonist JNJ-64413739 is 1.0 ± 0.2 nM and 2.0 ± 0.6 nM at the recombinant human and rat P2X7 receptor, respectively, and the binding affinity is 2.7 nM (rat cortex binding assay) and 15.9 nM (human P2X7 receptor). In nonhuman primate PET imaging studies, dose-dependent receptor occupancy of JNJ-54175446 was observed in 2 rhesus monkeys. At a 0.1 mg/kg dose (intravenous) of JNJ-54175446, the receptor occupancy was calculated to be 17% by Logan graphical analysis, whereas a dose of 2.5 mg/kg yielded a receptor occupancy of 60%. Conclusion: The preclinical evaluation of 18F-JNJ-64413739 demonstrates that the tracer engages the P2X7 receptor. Reproducible and dose-dependent receptor occupancy studies with the P2X7 receptor antagonist JNJ-54175446 were obtained in rhesus monkeys. This novel PET tracer exhibits in vitro and in vivo characteristics suitable for imaging the P2X7 receptor in the brain and warrants further studies in humans.
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Affiliation(s)
- Hartmuth C Kolb
- Janssen Research and Development LLC, San Diego, California; and
| | | | | | - Gang Chen
- Janssen Research and Development LLC, San Diego, California; and
| | | | - Chaofeng Huang
- Janssen Research and Development LLC, San Diego, California; and
| | - Michael Letavic
- Janssen Research and Development LLC, San Diego, California; and
| | | | - Chunfang A Xia
- Janssen Research and Development LLC, San Diego, California; and
| | - Wei Zhang
- Janssen Research and Development LLC, San Diego, California; and
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68
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Gao M, Wang M, Glick-Wilson BE, Meyer JA, Peters JS, Territo PR, Green MA, Hutchins GD, Zarrinmayeh H, Zheng QH. Synthesis and initial in vitro characterization of a new P2X7R radioligand [18F]IUR-1602. Appl Radiat Isot 2019; 144:10-18. [DOI: 10.1016/j.apradiso.2018.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/29/2018] [Accepted: 11/13/2018] [Indexed: 11/25/2022]
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69
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Fu Z, Lin Q, Hu B, Zhang Y, Chen W, Zhu J, Zhao Y, Choi HS, Shi H, Cheng D. P2X7 PET Radioligand 18F-PTTP for Differentiation of Lung Tumor from Inflammation. J Nucl Med 2019; 60:930-936. [PMID: 30655332 DOI: 10.2967/jnumed.118.222547] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 12/10/2018] [Indexed: 12/28/2022] Open
Abstract
Site-specific imaging agents play a key role in tumor targeting, but only a few agents are currently available for inflammation targeting. Since the P2X7 receptor (P2X7R) is a promising molecular target for inflammation, we evaluated the potential value of the 18F-labeled tracer 18F-PTTP (5-{[2-Chloro-3-(trifluoromethyl)phenyl]carbonyl}-1-pyrimidin-2-yl-4,5,6,7-tetrahydro-1H-[1,2,3]triazolo[4,5-c]pyridin) for targeting P2X7Rs and thus differentiating inflammation from tumors. Methods: The radioligand 18F-PTTP was achieved by a 1-step 18F-trifluoromethylation reaction. The binding affinity of the ligand for P2X7R and its stability were evaluated in vitro. Blood pharmacokinetics tests and biodistribution studies were performed in vivo. Dynamic 18F-PTTP small-animal PET/CT imaging was performed for 60 min on A549 tumor-bearing mice and inflammation-model mice for targeting differentiation. Results: 18F-PTTP was afforded with decay-corrected radiochemical yields of 2.5%-7.0%, specific activity of 296-370 MBq/μmol, and radiochemical purity over 95%. 18F-PTTP showed excellent stability in 0.9% NaCl and 0.1% bovine serum albumin, good affinity to RAW264.7 cells, and rapid blood clearance in mice. In inflammation-model mice, uptake of 18F-PTTP peaked at 5 min after injection and kept at an imageable level till 30 min, whereas no significant radioactivity uptake was found in tumor grafts till 1 h after injection. The specificity of 18F-PTTP was verified by blocking studies and histologic analysis. Conclusion: The current study provides compelling data that 18F-PTTP is a novel radioligand targeting P2X7R and has potential to screen new drugs, quantify peripheral inflammation, and distinguish inflammation from certain solid tumors.
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Affiliation(s)
- Zhequan Fu
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qingyu Lin
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Medical Imaging, Shanghai, China; and
| | - Bingxin Hu
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yingying Zhang
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Weijia Chen
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Zhu
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yanzhao Zhao
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Hak Soo Choi
- Department of Radiology, Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hongcheng Shi
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China .,Shanghai Institute of Medical Imaging, Shanghai, China; and
| | - Dengfeng Cheng
- Department of Nuclear Medicine, Zhongshan Hospital, Fudan University, Shanghai, China .,Shanghai Institute of Medical Imaging, Shanghai, China; and
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Inhibitors of NF-κB and P2X7/NLRP3/Caspase 1 pathway in microglia: Novel therapeutic opportunities in neuroinflammation induced early-stage Alzheimer’s disease. J Neuroimmunol 2019; 326:62-74. [DOI: 10.1016/j.jneuroim.2018.11.010] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 12/21/2022]
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71
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Development of brain PET imaging agents: Strategies for imaging neuroinflammation in Alzheimer's disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 165:371-399. [DOI: 10.1016/bs.pmbts.2019.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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72
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Erickson EK, Grantham EK, Warden AS, Harris RA. Neuroimmune signaling in alcohol use disorder. Pharmacol Biochem Behav 2018; 177:34-60. [PMID: 30590091 DOI: 10.1016/j.pbb.2018.12.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/25/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023]
Abstract
Alcohol use disorder (AUD) is a widespread disease with limited treatment options. Targeting the neuroimmune system is a new avenue for developing or repurposing effective pharmacotherapies. Alcohol modulates innate immune signaling in different cell types in the brain by altering gene expression and the molecular pathways that regulate neuroinflammation. Chronic alcohol abuse may cause an imbalance in neuroimmune function, resulting in prolonged perturbations in brain function. Likewise, manipulating the neuroimmune system may change alcohol-related behaviors. Psychiatric disorders that are comorbid with AUD, such as post-traumatic stress disorder, major depressive disorder, and other substance use disorders, may also have underlying neuroimmune mechanisms; current evidence suggests that convergent immune pathways may be involved in AUD and in these comorbid disorders. In this review, we provide an overview of major neuroimmune cell-types and pathways involved in mediating alcohol behaviors, discuss potential mechanisms of alcohol-induced neuroimmune activation, and present recent clinical evidence for candidate immune-related drugs to treat AUD.
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Affiliation(s)
- Emma K Erickson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA.
| | - Emily K Grantham
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
| | - Anna S Warden
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
| | - R A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712-01095, USA
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73
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Beckers L, Ory D, Geric I, Declercq L, Koole M, Kassiou M, Bormans G, Baes M. Increased Expression of Translocator Protein (TSPO) Marks Pro-inflammatory Microglia but Does Not Predict Neurodegeneration. Mol Imaging Biol 2018; 20:94-102. [PMID: 28695372 DOI: 10.1007/s11307-017-1099-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE Activation of the innate immune system plays a significant role in pathologies of the central nervous system (CNS). In order to follow disease progression and evaluate effectiveness of potential treatments involved in neuroinflammation, it is important to track neuroinflammatory markers in vivo longitudinally. The translocator protein (TSPO) is used as a target to image neuroinflammation as its expression is upregulated in reactive glial cells during CNS pathologies. However, it remains unclear in which microglial phenotypes TSPO levels are upregulated, as microglia can display a plethora of activation states that can be protective or detrimental to the CNS. PROCEDURES We assessed the levels of TSPO transcripts in cultured microglia that were polarized into pro- and anti-inflammatory states in vitro and in the brain of mice in which an anti-inflammatory environment was induced in vivo. In addition, we used a mouse model of peroxisomal multifunctional protein-2 (MFP2) deficiency that exhibits widespread neuroinflammation despite no neuronal loss and monitored TSPO expression by immunohistochemistry and by imaging using the TSPO radiotracer [18F]DPA-714. RESULTS TSPO expression was selectively increased in so-called classically activated or M1 microglia but not in alternatively activated or M2 microglia in vitro. In agreement, TSPO transcript levels were not induced in an anti-inflammatory brain environment. We found that both transcript and protein levels of TSPO are significantly increased in the brain of Mfp2 -/- compared to those of the control mice and TSPO immunoreactivity colocalized predominantly with microglia in Mfp2 -/- brain. In vitro and ex vivo autoradiography in Mfp2 -/- mice using the TSPO radiotracer [18F]DPA-714 confirmed increased expression of TSPO. These data demonstrate that TSPO imaging reveals microgliosis in non-neurodegenerative brain pathologies. CONCLUSIONS We show that induced TSPO expression marks a pro-inflammatory brain environment that is not necessarily accompanied by neuronal loss.
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Affiliation(s)
- Lien Beckers
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Cell Metabolism, KU Leuven - University of Leuven, Campus Gasthuisberg O/N2, Herestraat 49, 3000, Leuven, Belgium
| | - Dieter Ory
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Radiopharmacy, KU Leuven - University of Leuven, Leuven, Belgium
| | - Ivana Geric
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Cell Metabolism, KU Leuven - University of Leuven, Campus Gasthuisberg O/N2, Herestraat 49, 3000, Leuven, Belgium
| | - Lieven Declercq
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Radiopharmacy, KU Leuven - University of Leuven, Leuven, Belgium
| | - Michel Koole
- Department of Nuclear Medicine and Molecular Imaging, KU Leuven- University of Leuven, Leuven, Belgium
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Guy Bormans
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Radiopharmacy, KU Leuven - University of Leuven, Leuven, Belgium
| | - Myriam Baes
- Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Cell Metabolism, KU Leuven - University of Leuven, Campus Gasthuisberg O/N2, Herestraat 49, 3000, Leuven, Belgium.
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Bhattacharya A, Lord B, Grigoleit JS, He Y, Fraser I, Campbell SN, Taylor N, Aluisio L, O’Connor JC, Papp M, Chrovian C, Carruthers N, Lovenberg TW, Letavic MA. Neuropsychopharmacology of JNJ-55308942: evaluation of a clinical candidate targeting P2X7 ion channels in animal models of neuroinflammation and anhedonia. Neuropsychopharmacology 2018; 43:2586-2596. [PMID: 30026598 PMCID: PMC6224414 DOI: 10.1038/s41386-018-0141-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 11/09/2022]
Abstract
Emerging data continues to point towards a relationship between neuroinflammation and neuropsychiatric disorders. ATP-induced activation of P2X7 results in IL-1β release causing neuroinflammation and microglial activation. This study describes the in-vitro and in-vivo neuropharmacology of a novel brain-penetrant P2X7 antagonist, JNJ-55308942, currently in clinical development. JNJ-55308942 is a high-affinity, selective, brain-penetrant (brain/plasma of 1) P2X7 functional antagonist. In human blood and in mouse blood and microglia, JNJ-55308942 attenuated IL-1β release in a potent and concentration-dependent manner. After oral dosing, the compound exhibited both dose and concentration-dependent occupancy of rat brain P2X7 with an ED50 of 0.07 mg/kg. The P2X7 antagonist (3 mg/kg, oral) blocked Bz-ATP-induced brain IL-1β release in conscious rats, demonstrating functional effects of target engagement in the brain. JNJ-55308942 (30 mg/kg, oral) attenuated LPS-induced microglial activation in mice, assessed at day 2 after a single systemic LPS injection (0.8 mg/kg, i.p.), suggesting a role for P2X7 in microglial activation. In a model of BCG-induced depression, JNJ-55308942 dosed orally (30 mg/kg), reversed the BCG-induced deficits of sucrose preference and social interaction, indicating for the first time a role of P2X7 in the BCG model of depression, probably due to the neuroinflammatory component induced by BCG inoculation. Finally, in a rat model of chronic stress induced sucrose intake deficit, JNJ-55308942 reversed the deficit with concurrent high P2X7 brain occupancy as measured by autoradiography. This body of data demonstrates that JNJ-55308942 is a potent P2X7 antagonist, engages the target in brain, modulates IL-1β release and microglial activation leading to efficacy in two models of anhedonia in rodents.
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Affiliation(s)
- Anindya Bhattacharya
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA, 92131, USA.
| | - Brian Lord
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | | | - Yingbo He
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Ian Fraser
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Shannon N. Campbell
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Natalie Taylor
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Leah Aluisio
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Jason C. O’Connor
- 0000 0004 0617 9080grid.414059.dDepartment of Pharmacology, UT Health San Antonio, 7703 Floyd Curl Dr. and Audie L. Murphy VA Hospital, 7400 Merton Minter Blvd, San Antonio, TX 78229 USA
| | - Mariusz Papp
- 0000 0001 2227 8271grid.418903.7Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, Krakow, 31-343 Poland
| | - Christa Chrovian
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Nicholas Carruthers
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Timothy W. Lovenberg
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
| | - Michael A. Letavic
- Janssen Research & Development, LLC. Neuroscience Therapeutic Area, San Diego, CA 92131 USA
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75
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Wissmann CL, Wang M, Gao M, Zheng QH, Green MA. Development, validation and implementation of radio-HPLC methods for the P2X7-receptor-targeted [11C]GSK1482160 radiopharmaceutical. Appl Radiat Isot 2018; 142:8-11. [DOI: 10.1016/j.apradiso.2018.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 10/28/2022]
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76
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Bhattacharya A, Jones DNC. Emerging role of the P2X7-NLRP3-IL1β pathway in mood disorders. Psychoneuroendocrinology 2018; 98:95-100. [PMID: 30121550 DOI: 10.1016/j.psyneuen.2018.08.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/03/2018] [Accepted: 08/09/2018] [Indexed: 12/30/2022]
Abstract
The science of neuroimmunopsychiatry has evolved rapidly in the last few years with the hope of tackling the unmet need in mood disorders. This article focuses on an inflammatory pathway, highly conserved in myeloid cells that may play a role in neuroinflammatory disorders including depression. Within the brain tissue, microglia are the myeloid cells that express the P2X7 ion channel that is connected through the NLRP3 inflammasome complex leading to release of IL-1β and IL-18. We present, in the way of reviewing relevant literature, the preclinical data and scientific rationale supporting the role of the P2X7-NLRP3-IL-1β pathway in mood disorders. We also highlight recent advances in drug discovery and development of P2X7 small molecule antagonists and P2X7 PET ligands which provide optimism that clinical tools are availableto address critical proof-of-concept experiments in mood disorders.
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Affiliation(s)
- Anindya Bhattacharya
- Janssen Research & Development, Neuroscience Therapeutic Area, 3210 Merryfield Row, San Diego, CA 92121, United States.
| | - Declan N C Jones
- Neuroscience External Innovation, Johnson & Johnson Innovation Centre, One Chapel Place, London, W1G 0BG, United Kingdom
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77
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Shen Z, Bao X, Wang R. Clinical PET Imaging of Microglial Activation: Implications for Microglial Therapeutics in Alzheimer's Disease. Front Aging Neurosci 2018; 10:314. [PMID: 30349474 PMCID: PMC6186779 DOI: 10.3389/fnagi.2018.00314] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
In addition to extracellular β-amyloid plaques and intracellular neurofibrillary tangles, neuroinflammation has been identified as a key pathological characteristic of Alzheimer's disease (AD). Once activated, neuroinflammatory cells called microglia acquire different activation phenotypes. At the early stage of AD, activated microglia are mainly dominated by the neuroprotective and anti-inflammatory M2 phenotype. Conversely, in the later stage of AD, the excessive activation of microglia is considered detrimental and pro-inflammatory, turning into the M1 phenotype. Therapeutic strategies targeting the modulation of microglia may regulate their specific phenotype. Fortunately, with the rapid development of in vivo imaging methodologies, visualization of microglial activation has been well-explored. In this review, we summarize the critical role of activated microglia during the pathogenesis of AD and current studies concerning imaging of microglial activation in AD patients. We explore the possibilities for identifying activated microglial phenotypes with imaging techniques and highlight promising therapies that regulate the microglial phenotype in AD mice.
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Affiliation(s)
- Zhiwei Shen
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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78
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Koole M, Schmidt ME, Hijzen A, Ravenstijn P, Vandermeulen C, Van Weehaeghe D, Serdons K, Celen S, Bormans G, Ceusters M, Zhang W, Van Nueten L, Kolb H, de Hoon J, Van Laere K. 18F-JNJ-64413739, a Novel PET Ligand for the P2X7 Ion Channel: Radiation Dosimetry, Kinetic Modeling, Test-Retest Variability, and Occupancy of the P2X7 Antagonist JNJ-54175446. J Nucl Med 2018; 60:683-690. [PMID: 30262518 DOI: 10.2967/jnumed.118.216747] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/18/2018] [Indexed: 12/27/2022] Open
Abstract
The P2X7 receptor (P2X7R) is an adenosine triphosphate-gated ion channel that is predominantly expressed on microglial cells in the central nervous system. We report the clinical qualification of P2X7-specific PET ligand 18F-JNJ-64413739 in healthy volunteers, including dosimetry, kinetic modeling, test-retest variability, and blocking by the P2X7 antagonist JNJ-54175446. Methods: Whole-body dosimetry was performed in 3 healthy male subjects by consecutive whole-body PET/CT scanning, estimation of the normalized cumulated activity, and calculation of the effective dose using OLINDA (v1.1). Next, 5 healthy male subjects underwent a 120-min dynamic 18F-JNJ-64413739 PET/MRI scan with arterial blood sampling to determine the appropriate kinetic model. For this purpose, 1- and 2-tissue compartment models and Logan graphic analysis (LGA) were evaluated for estimating regional volumes of distribution (VT). PET/MRI scanning was repeated in 4 of these subjects to evaluate medium-term test-retest variability (interscan interval, 26-97 d). For the single-dose occupancy study, 8 healthy male subjects underwent baseline and postdose 18F-JNJ-64413739 PET/MRI scans 4-6 h after the administration of a single oral dose of JNJ-54175446 (dose range, 5-300 mg). P2X7 occupancies were estimated using a Lassen plot and regional baseline and postdose VT Results: The average (mean ± SD) effective dose was 22.0 ± 1.0 μSv/MBq. The 2-tissue compartment model was the most appropriate kinetic model, with LGA showing very similar results. Regional 2-tissue compartment model VT values were about 3 and were rather homogeneous across all brain regions, with slightly higher estimates for the thalamus, striatum, and brain stem. Between-subject VT variability was relatively high, with cortical VT showing an approximate 3-fold range across subjects. As for time stability, the acquisition time could be reduced to 90 min. The average regional test-retest variability values were 10.7% ± 2.2% for 2-tissue compartment model VT and 11.9% ± 2.2% for LGA VT P2X7 occupancy approached saturation for single doses of JNJ-54175446 higher than 50 mg, and no reference region could be identified. Conclusion: 18F-JNJ-64413739 is a suitable PET ligand for the quantification of P2X7R expression in the human brain. It can be used to provide insight into P2X7R expression in health and disease, to evaluate target engagement by P2X7 antagonists, and to guide dose selection.
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Affiliation(s)
- Michel Koole
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium.,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | | | - Anja Hijzen
- Janssen Research and Development, Beerse, Belgium
| | | | - Corinne Vandermeulen
- Center for Clinical Pharmacology, University Hospitals Leuven, Leuven, Belgium; and
| | - Donatienne Van Weehaeghe
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium
| | - Kim Serdons
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium
| | - Sofie Celen
- Laboratory for Radiopharmaceutical Research, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, KU Leuven, Leuven, Belgium
| | | | - Wei Zhang
- Janssen Research and Development, Beerse, Belgium
| | | | | | - Jan de Hoon
- Center for Clinical Pharmacology, University Hospitals Leuven, Leuven, Belgium; and
| | - Koen Van Laere
- Division of Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Leuven, Belgium .,Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
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79
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Högel H, Rissanen E, Vuorimaa A, Airas L. Positron emission tomography imaging in evaluation of MS pathology in vivo. Mult Scler 2018; 24:1399-1412. [DOI: 10.1177/1352458518791680] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Positron emission tomography (PET) gives an opportunity to quantitate the expression of specific molecular targets in vivo and longitudinally in brain and thus enhances our possibilities to understand and follow up multiple sclerosis (MS)-related pathology. For successful PET imaging, one needs a relevant target molecule within the brain, to which a blood–brain barrier–penetrating specific radioligand will bind. 18-kDa translocator protein (TSPO)-binding radioligands have been used to detect activated microglial cells at different stages of MS, and remyelination has been measured using amyloid PET. Several PET ligands for the detection of other inflammatory targets, besides TSPO, have been developed but not yet been used for imaging MS patients. Finally, synaptic density evaluation has been successfully tested in human subjects and gives opportunities for the evaluation of the development of cortical and deep gray matter pathology in MS. This review will discuss PET imaging modalities relevant for MS today.
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Affiliation(s)
- Heidi Högel
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Anna Vuorimaa
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Laura Airas
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
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80
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Auberson YP, Briard E, Rudolph B, Kaupmann K, Smith P, Oberhauser B. PET Imaging of T Cells: Target Identification and Feasibility Assessment. ChemMedChem 2018; 13:1566-1579. [DOI: 10.1002/cmdc.201800241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/23/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Yves P. Auberson
- Global Discovery Chemistry Novartis Institutes for BioMedical Research 141 Klybeckstrasse 4057 Basel Switzerland
| | - Emmanuelle Briard
- Global Discovery Chemistry Novartis Institutes for BioMedical Research 141 Klybeckstrasse 4057 Basel Switzerland
| | - Bettina Rudolph
- Translational Medicine, Pharmacokinetics Sciences Novartis Institutes for BioMedical Research Novartis Campus 4056 Basel Switzerland
| | - Klemens Kaupmann
- Autoimmunity, Transplantation & Inflammation Novartis Institutes for BioMedical Research Novartis Campus 4056 Basel Switzerland
| | - Paul Smith
- Autoimmunity, Transplantation & Inflammation Novartis Institutes for BioMedical Research Novartis Campus 4056 Basel Switzerland
| | - Berndt Oberhauser
- Global Discovery Chemistry Novartis Institutes for BioMedical Research 141 Klybeckstrasse 4057 Basel Switzerland
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81
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Jiemy WF, Heeringa P, Kamps JA, van der Laken CJ, Slart RH, Brouwer E. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging of macrophages in large vessel vasculitis: Current status and future prospects. Autoimmun Rev 2018; 17:715-726. [DOI: 10.1016/j.autrev.2018.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 02/07/2018] [Indexed: 12/21/2022]
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82
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Janssen B, Vugts DJ, Wilkinson SM, Ory D, Chalon S, Hoozemans JJM, Schuit RC, Beaino W, Kooijman EJM, van den Hoek J, Chishty M, Doméné A, Van der Perren A, Villa A, Maggi A, Molenaar GT, Funke U, Shevchenko RV, Baekelandt V, Bormans G, Lammertsma AA, Kassiou M, Windhorst AD. Identification of the allosteric P2X 7 receptor antagonist [ 11C]SMW139 as a PET tracer of microglial activation. Sci Rep 2018; 8:6580. [PMID: 29700413 PMCID: PMC5920098 DOI: 10.1038/s41598-018-24814-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/15/2018] [Indexed: 02/07/2023] Open
Abstract
The P2X7 receptor plays a significant role in microglial activation, and as a potential drug target, the P2X7 receptor is also an interesting target in positron emission tomography. The current study aimed at the development and evaluation of a potent tracer targeting the P2X7 receptor, to which end four adamantanyl benzamide analogues with high affinity for the human P2X7 receptor were labelled with carbon-11. All four analogues could be obtained in excellent radiochemical yield and high radiochemical purity and molar activity, and all analogues entered the rat brain. [11C]SMW139 showed the highest metabolic stability in rat plasma, and showed high binding to the hP2X7 receptor in vivo in a hP2X7 receptor overexpressing rat model. Although no significant difference in binding of [11C]SMW139 was observed between post mortem brain tissue of Alzheimer's disease patients and that of healthy controls in in vitro autoradiography experiments, [11C]SMW139 could be a promising tracer for P2X7 receptor imaging using positron emission tomography, due to high receptor binding in vivo in the hP2X7 receptor overexpressing rat model. However, further investigation of both P2X7 receptor expression and binding of [11C]SMW139 in other neurological diseases involving microglial activation is warranted.
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Affiliation(s)
- Bieneke Janssen
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
| | - Danielle J Vugts
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Dieter Ory
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Sylvie Chalon
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
| | - Jeroen J M Hoozemans
- Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - Wissam Beaino
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - Esther J M Kooijman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - Johan van den Hoek
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - Mansoor Chishty
- Pharmidex Pharmaceutical Services Ltd., London, United Kingdom
| | - Aurélie Doméné
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
| | - Anke Van der Perren
- Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Alessandro Villa
- Center of Excellence on Neurodegenerative Diseases and Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Adriana Maggi
- Center of Excellence on Neurodegenerative Diseases and Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Ger T Molenaar
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
- BV Cyclotron VU, Amsterdam, The Netherlands
| | - Uta Funke
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
- BV Cyclotron VU, Amsterdam, The Netherlands
| | | | - Veerle Baekelandt
- Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - Michael Kassiou
- School of Chemistry, University of Sydney, Sydney, Australia
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
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83
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Linking Neuroinflammation and Neurodegeneration in Parkinson's Disease. J Immunol Res 2018; 2018:4784268. [PMID: 29850629 PMCID: PMC5926497 DOI: 10.1155/2018/4784268] [Citation(s) in RCA: 289] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/28/2018] [Indexed: 11/30/2022] Open
Abstract
Neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD) impose a pressing burden on our developed and consequently aging society. Misfolded protein aggregates are a critical aspect of several neurodegenerative diseases. Nevertheless, several questions remain unanswered regarding the role of misfolded protein aggregates and the cause of neuronal cell death. Recently, it has been postulated that neuroinflammatory processes might play a crucial role in the pathogenesis of PD. Numerous postmortem, brain imaging, epidemiological, and animal studies have documented the involvement of the innate and adaptive immunity in neurodegeneration. Whether these inflammatory processes are directly involved in the etiology of PD or represent secondary consequences of nigrostriatal pathway injury is the subject of intensive research. Immune alterations in response to extracellular α-synuclein may play a critical role in modulating Parkinson's disease progression. In this review, we address the current concept of neuroinflammation and its involvement in PD-associated neurodegeneration.
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84
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Airas L, Nylund M, Rissanen E. Evaluation of Microglial Activation in Multiple Sclerosis Patients Using Positron Emission Tomography. Front Neurol 2018; 9:181. [PMID: 29632509 PMCID: PMC5879102 DOI: 10.3389/fneur.2018.00181] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/08/2018] [Indexed: 01/24/2023] Open
Abstract
Understanding the mechanisms underlying progression in multiple sclerosis (MS) is one of the key elements contributing to the identification of appropriate therapeutic targets for this under-managed condition. In addition to plaque-related focal inflammatory pathology typical for relapsing remitting MS there are, in progressive MS, widespread diffuse alterations in brain areas outside the focal lesions. This diffuse pathology is tightly related to microglial activation and is co-localized with signs of neurodegeneration. Microglia are brain-resident cells of the innate immune system and overactivation of microglia is associated with several neurodegenerative diseases. Understanding the role of microglial activation in relation to developing neurodegeneration and disease progression may provide a key to developing therapies to target progressive MS. 18-kDa translocator protein (TSPO) is a mitochondrial molecule upregulated in microglia upon their activation. Positron emission tomography (PET) imaging using TSPO-binding radioligands provides a method to assess microglial activation in patients in vivo. In this mini-review, we summarize the current status of TSPO imaging in the field of MS. In addition, the review discusses new insights into the potential use of this method in treatment trials and in clinical assessment of progressive MS.
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Affiliation(s)
- Laura Airas
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Marjo Nylund
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
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85
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Gao M, Wang M, Glick-Wilson BE, Meyer JA, Peters JS, Territo PR, Green MA, Hutchins GD, Zarrinmayeh H, Zheng QH. Synthesis and preliminary biological evaluation of a novel P2X7R radioligand [ 18F]IUR-1601. Bioorg Med Chem Lett 2018; 28:1603-1609. [PMID: 29628324 DOI: 10.1016/j.bmcl.2018.03.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 02/27/2018] [Accepted: 03/17/2018] [Indexed: 01/02/2023]
Abstract
The reference standard IUR-1601 ((S)-N-(2-chloro-3-(trifluoromethyl)benzyl)-1-(2-fluoroethyl)-5-oxopyrrolidine-2-carboxamide) was synthesized from tert-butyl (S)-5-oxopyrrolidine-2-carboxylate, fluoroethylbromide, and 2-chloro-3-(trifluoromethyl)benzylamine with overall chemical yield 12% in three steps. The target tracer [18F]IUR-1601 ((S)-N-(2-chloro-3-(trifluoromethyl)benzyl)-1-(2-[18F]fluoroethyl)-5-oxopyrrolidine-2-carboxamide) was synthesized from desmethyl-GSK1482160 with 2-[18F]fluoroethyl tosylate, prepared from 1,2-ethylene glycol-bis-tosylate and K[18F]F/Kryptofix2.2.2, in two steps and isolated by HPLC combined with SPE in 1-3% decay corrected radiochemical yield. The radiochemical purity was >99%, and the molar activity at end of bombardment (EOB) was 74-370 GBq/μmol. The potency of IUR-1601 in comparison with GSK1482160 was determined by a radioligand competitive binding assay using [11C]GSK1482160, and the binding affinity Ki values for IUR-1601 and GSK1482160 are 4.31 and 5.14 nM, respectively.
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Affiliation(s)
- Mingzhang Gao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Barbara E Glick-Wilson
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Jill A Meyer
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Jonathan S Peters
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Paul R Territo
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Mark A Green
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Gary D Hutchins
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Hamideh Zarrinmayeh
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
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86
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Dal Ben D, Antonioli L, Lambertucci C, Fornai M, Blandizzi C, Volpini R. Purinergic Ligands as Potential Therapeutic Tools for the Treatment of Inflammation-Related Intestinal Diseases. Front Pharmacol 2018; 9:212. [PMID: 29593540 PMCID: PMC5861216 DOI: 10.3389/fphar.2018.00212] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/26/2018] [Indexed: 12/13/2022] Open
Abstract
Inflammation-related intestinal diseases are a set of various conditions presenting an overactive enteric immune system. A continuous overproduction of pro-inflammatory cytokines and a decreased production of anti-inflammatory modulators are generally observed, while morpho-functional alterations of the enteric nervous system lead to intestinal secretory and motor dysfunctions. The factors at the basis of these conditions are still to be totally identified and current therapeutic strategies are aimed only at achieving and maintaining remission states, by using therapeutic tools like aminosalicylates, corticosteroids, immunomodulators, biological drugs (i.e., monoclonal antibodies), and eventually surgery. Recent reports described a key role of purinergic mediators (i.e., adenosine and its nucleotides ATP and ADP) in the regulation of the activity of immune cells and enteric nervous system, showing also that alterations of the purinergic signaling are linked to pathological conditions of the intestinal tract. These data prompted to a series of investigations to test the therapeutic potential for inflammation-related intestinal conditions of compounds able to restore or modulate an altered purinergic signaling within the gut. This review provides an overview on these investigations, describing the results of preclinical and/or clinical evaluation of compounds able to stimulate or inhibit specific P2 (i.e., P2X7) or P1 (i.e., A2A or A3) receptor signaling and to modify the adenosine levels through the modulation of enzymes activity (i.e., Adenosine Deaminase) or nucleoside transporters. Recent developments in the field are also reported and the most promising purine-based therapeutic strategies for the treatment of inflammation-related gastrointestinal disorders are schematically summarized.
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Affiliation(s)
- Diego Dal Ben
- Medicinal Chemistry Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Luca Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Catia Lambertucci
- Medicinal Chemistry Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Matteo Fornai
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Corrado Blandizzi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Rosaria Volpini
- Medicinal Chemistry Unit, School of Pharmacy, University of Camerino, Camerino, Italy
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87
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Abstract
Neuroinflammation, which involves microglial activation, is thought to play a key role in the development and progression of neurodegenerative diseases and other brain pathologies. Positron emission tomography is an ideal imaging technique for studying biochemical processes in vivo, and particularly for studying the living brain. Neuroinflammation has been traditionally studied using radiotracers targeting the translocator protein 18 kDa, but this comes with certain limitations. The current review describes alternative biological targets that have gained interest for the imaging of microglial activation over recent years, such as the cannabinoid receptor type 2, cyclooxygenase-2, the P2X₇ receptor and reactive oxygen species, and some promising radiotracers for these targets. Although many advances have been made in the field of neuroinflammation imaging, current radiotracers all target the pro-inflammatory (M1) phenotype of activated microglia, since the number of known biological targets specific for the anti-inflammatory (M2) phenotype that are also suited as a target for radiotracer development is still limited. Next to proceeding the currently available tracers for M1 microglia into the clinic, the development of a suitable radiotracer for M2 microglia would mean a great advance in the field, as this would allow for imaging of the dynamics of microglial activation in different diseases.
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Affiliation(s)
- Bieneke Janssen
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Danielle J Vugts
- Department of Radiology & Nuclear Medicine, VU University Medical Center, 1081 HV Amsterdam, The Netherlands.
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, 1081 HV Amsterdam, The Netherlands.
| | - Robert H Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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88
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Burnstock G, Knight GE. The potential of P2X7 receptors as a therapeutic target, including inflammation and tumour progression. Purinergic Signal 2018; 14:1-18. [PMID: 29164451 PMCID: PMC5842154 DOI: 10.1007/s11302-017-9593-0] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/01/2017] [Indexed: 12/22/2022] Open
Abstract
Seven P2X ion channel nucleotide receptor subtypes have been cloned and characterised. P2X7 receptors (P2X7R) are unusual in that there are extra amino acids in the intracellular C terminus. Low concentrations of ATP open cation channels sometimes leading to cell proliferation, whereas high concentrations of ATP open large pores that release inflammatory cytokines and can lead to apoptotic cell death. Since many diseases involve inflammation and immune responses, and the P2X7R regulates inflammation, there has been recent interest in the pathophysiological roles of P2X7R and the potential of P2X7R antagonists to treat a variety of diseases. These include neurodegenerative diseases, psychiatric disorders, epilepsy and a number of diseases of peripheral organs, including the cardiovascular, airways, kidney, liver, bladder, skin and musculoskeletal. The potential of P2X7R drugs to treat tumour progression is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK.
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia.
- Florey Institute of Neuroscience and Mental Health, Parkville, Melbourne, Australia.
| | - Gillian E Knight
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK
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89
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Bhattacharya A. Recent Advances in CNS P2X7 Physiology and Pharmacology: Focus on Neuropsychiatric Disorders. Front Pharmacol 2018; 9:30. [PMID: 29449810 PMCID: PMC5799703 DOI: 10.3389/fphar.2018.00030] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/10/2018] [Indexed: 12/17/2022] Open
Abstract
The ATP-gated P2X7 ion channel is an abundant microglial protein in the CNS that plays an important pathological role in executing ATP-driven danger signal transduction. Emerging data has generated scientific interest and excitement around targeting the P2X7 ion channel as a potential drug target for CNS disorders. Over the past years, a wealth of data has been published on CNS P2X7 biology, in particular the role of P2X7 in microglial cells, and in vivo effects of brain-penetrant P2X7 antagonists. Likewise, significant progress has been made around the medicinal chemistry of CNS P2X7 ligands, as antagonists for in vivo target validation in models of CNS diseases, to identification of two clinical compounds (JNJ-54175446 and JNJ-55308942) and finally, discovery of P2X7 PET ligands. This review is an attempt to bring together the current understanding of P2X7 in the CNS with a focus on P2X7 as a drug target in neuropsychiatric disorders.
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Affiliation(s)
- Anindya Bhattacharya
- Neuroscience Therapeutic Area, Janssen Research and Development, LLC, San Diego, CA, United States
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90
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Pacilio M, Lauri C, Prosperi D, Petitti A, Signore A. New SPECT and PET Radiopharmaceuticals for Imaging Inflammatory Diseases: A Meta-analysis of the Last 10 Years. Semin Nucl Med 2018; 48:261-276. [PMID: 29626943 DOI: 10.1053/j.semnuclmed.2017.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Modern molecular nuclear medicine is rapidly developing in the field of imaging of chronic inflammatory diseases, and many new radiopharmaceuticals have been recently described and tested in animals and man. These can detect early pathophysiological changes before the development of anatomical changes and, often, before clinical onset of symptoms. This field includes new radiopharmaceuticals for SPECT and PET use to define new strategies for imaging immune cells as well as tissue modifications induced by the inflammatory process. In this review, we present the results of a meta-analysis based on radiopharmaceuticals (for SPECT or PET) that are not commercially available and that have been used, at least once, in humans in the last 10 years.
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Affiliation(s)
- Marta Pacilio
- Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, Italy
| | - Chiara Lauri
- Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, Italy.; Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Daniela Prosperi
- Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, Italy
| | - Agnese Petitti
- Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, Italy
| | - Alberto Signore
- Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, "Sapienza" University of Rome, Italy.; Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, The Netherlands.
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91
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Synthesis of N -(3-(4-[ 11 C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1 H -pyrazol-5-yl)pyrazolo[1,5- a ]pyrimidine-3-carboxamide as a new potential PET agent for imaging of IRAK4 enzyme in neuroinflammation. Appl Radiat Isot 2018; 132:6-12. [DOI: 10.1016/j.apradiso.2017.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/17/2017] [Accepted: 11/05/2017] [Indexed: 12/19/2022]
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92
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Narayanaswami V, Dahl K, Bernard-Gauthier V, Josephson L, Cumming P, Vasdev N. Emerging PET Radiotracers and Targets for Imaging of Neuroinflammation in Neurodegenerative Diseases: Outlook Beyond TSPO. Mol Imaging 2018; 17:1536012118792317. [PMID: 30203712 PMCID: PMC6134492 DOI: 10.1177/1536012118792317] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/31/2018] [Accepted: 07/09/2018] [Indexed: 11/16/2022] Open
Abstract
The dynamic and multicellular processes of neuroinflammation are mediated by the nonneuronal cells of the central nervous system, which include astrocytes and the brain's resident macrophages, microglia. Although initiation of an inflammatory response may be beneficial in response to injury of the nervous system, chronic or maladaptive neuroinflammation can have harmful outcomes in many neurological diseases. An acute neuroinflammatory response is protective when activated neuroglia facilitate tissue repair by releasing anti-inflammatory cytokines and neurotrophic factors. On the other hand, chronic neuroglial activation is a major pathological mechanism in neurodegenerative diseases, likely contributing to neuronal dysfunction, injury, and disease progression. Therefore, the development of specific and sensitive probes for positron emission tomography (PET) studies of neuroinflammation is attracting immense scientific and clinical interest. An early phase of this research emphasized PET studies of the prototypical imaging biomarker of glial activation, translocator protein-18 kDa (TSPO), which presents difficulties for quantitation and lacks absolute cellular specificity. Many alternate molecular targets present themselves for PET imaging of neuroinflammation in vivo, including enzymes, intracellular signaling molecules as well as ionotropic, G-protein coupled, and immunoglobulin receptors. We now review the lead structures in radiotracer development for PET studies of neuroinflammation targets for neurodegenerative diseases extending beyond TSPO, including glycogen synthase kinase 3, monoamine oxidase-B, reactive oxygen species, imidazoline-2 binding sites, cyclooxygenase, the phospholipase A2/arachidonic acid pathway, sphingosine-1-phosphate receptor-1, cannabinoid-2 receptor, the chemokine receptor CX3CR1, purinergic receptors: P2X7 and P2Y12, the receptor for advanced glycation end products, Mer tyrosine kinase, and triggering receptor expressed on myeloid cells-1. We provide a brief overview of the cellular expression and function of these targets, noting their selectivity for astrocytes and/or microglia, and highlight the classes of PET radiotracers that have been investigated in early-stage preclinical or clinical research studies of neuroinflammation.
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Affiliation(s)
- Vidya Narayanaswami
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Kenneth Dahl
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Vadim Bernard-Gauthier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Paul Cumming
- School of Psychology and Counselling and IHBI, Queensland University of Technology, Brisbane, Queensland, Australia
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Neil Vasdev
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, MA, USA
- Azrieli Centre for Neuro-Radiochemistry, Research Imaging Centre, Centre for Addiction and Mental Health & Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
- Department of Radiology, Harvard Medical School, Boston, MA, USA
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93
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Adinolfi E, Giuliani AL, De Marchi E, Pegoraro A, Orioli E, Di Virgilio F. The P2X7 receptor: A main player in inflammation. Biochem Pharmacol 2017; 151:234-244. [PMID: 29288626 DOI: 10.1016/j.bcp.2017.12.021] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022]
Abstract
Damage associated molecular patterns (DAMPs) are intracellular molecules released from infected or injured cells to activate inflammatory and reparatory responses. One of the most ancient and conserved DAMPs is extracellular ATP that exerts its phlogistic activity mainly through activation of the P2X7 receptor (P2X7R). The P2X7R is an ATP gated ion channel, expressed by most immune cells, including the monocyte-derived cell lineages, T and B lymphocytes and their precursors. Here we give an overview of recent and established literature on the role of P2X7R in septic and sterile inflammation. P2X7R ability in restraining intracellular bacteria and parasite infection by modulation of the immune response are described, with particular focus on Mycobacteria and Plasmodium. Emerging literature on the role of P2X7 in viral infections such as HIV-1 is also briefly covered. Finally, we describe the numerous intracellular pathways related to inflammation and activated by the P2X7R, including the NLRP3 inflammasome, NF-kB, NFAT, GSK3β and VEGF, and discuss the involvement of P2X7R in chronic diseases. The possible therapeutic applications of P2X7R antagonists are also described.
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Affiliation(s)
- Elena Adinolfi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Anna Lisa Giuliani
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Elena De Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Anna Pegoraro
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Elisa Orioli
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Francesco Di Virgilio
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
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94
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Jin H, Han J, Resing D, Liu H, Yue X, Miller RL, Schoch KM, Miller TM, Perlmutter JS, Egan TM, Tu Z. Synthesis and in vitro characterization of a P2X7 radioligand [ 123I]TZ6019 and its response to neuroinflammation in a mouse model of Alzheimer disease. Eur J Pharmacol 2017; 820:8-17. [PMID: 29225193 DOI: 10.1016/j.ejphar.2017.12.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/21/2017] [Accepted: 12/04/2017] [Indexed: 02/08/2023]
Abstract
The purinergic receptor P2X ligand-gated ion channel 7 (P2X7 receptor) is a promising imaging target to detect neuroinflammation. Herein, we report development of a potent iodinated radiotracer for P2X7 receptor, [123I]TZ6019. The radiosynthesis of [123I]TZ6019 was accomplished by allylic-tin precursor iodination using [123I]NaI with good radiochemical yield of 85% and high radiochemical purity of > 99%. Human embryonic kidney 293 (HEK-293) cell line stably transfected with the human P2X7 receptor was used to characterize the binding affinity of TZ6019 by fluorescence, radioactive competitive, and saturation binding assays. A radioligand competitive binding assay with [123I]TZ6019 demonstrated that the nonradioactive compound TZ6019 has an IC50 value of 9.49 ± 1.4nM, and the known P2X7 receptor compound GSK1482160 has an IC50 value of 4.30 ± 0.86nM, consistent with previous reports. The radioligand saturation binding assay and competitive assay revealed that [123I]TZ6019 specifically bound to the human P2X7 receptor with high affinity (Ki = 6.3 ± 0.9nM). In vitro autoradiography quantification with brain slices collected from 9-month old P301S tau transgenic mice along with wild type controls, revealed higher binding of [123I]TZ6019 (35% increase) in the brain of P301S transgenic mice (n = 3, p = 0.04) compared to wild type controls. The immunofluorescence microscopy confirmed that expression of P2X7 receptor was colocalized with astrocytes in the tauopathy P301S transgenic mice. [123I]TZ6019 has specific binding for P2X7 receptor and has great potential to be a radiotracer for screening new compounds and quantifying expression of P2X7 receptor in neuroinflammation related diseases.
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Affiliation(s)
- Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Junbin Han
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Derek Resing
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Xuyi Yue
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rebecca L Miller
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kathleen M Schoch
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy M Miller
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joel S Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA; Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Terrance M Egan
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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95
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Di Virgilio F, Dal Ben D, Sarti AC, Giuliani AL, Falzoni S. The P2X7 Receptor in Infection and Inflammation. Immunity 2017; 47:15-31. [PMID: 28723547 DOI: 10.1016/j.immuni.2017.06.020] [Citation(s) in RCA: 766] [Impact Index Per Article: 109.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/14/2017] [Accepted: 06/27/2017] [Indexed: 12/11/2022]
Abstract
Adenosine triphosphate (ATP) accumulates at sites of tissue injury and inflammation. Effects of extracellular ATP are mediated by plasma membrane receptors named P2 receptors (P2Rs). The P2R most involved in inflammation and immunity is the P2X7 receptor (P2X7R), expressed by virtually all cells of innate and adaptive immunity. P2X7R mediates NLRP3 inflammasome activation, cytokine and chemokine release, T lymphocyte survival and differentiation, transcription factor activation, and cell death. Ten human P2RX7 gene splice variants and several SNPs that produce complex haplotypes are known. The P2X7R is a potent stimulant of inflammation and immunity and a promoter of cancer cell growth. This makes P2X7R an appealing target for anti-inflammatory and anti-cancer therapy. However, an in-depth knowledge of its structure and of the associated signal transduction mechanisms is needed for an effective therapeutic development.
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Affiliation(s)
- Francesco Di Virgilio
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.
| | - Diego Dal Ben
- School of Pharmacy, University of Camerino, Camerino, Italy
| | - Alba Clara Sarti
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Anna Lisa Giuliani
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Simonetta Falzoni
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
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96
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Gao M, Wang M, Meyer JA, Peters JS, Zarrinmayeh H, Territo PR, Hutchins GD, Zheng QH. Synthesis and preliminary biological evaluation of [ 11 C]methyl (2-amino-5-(benzylthio)thiazolo[4,5- d ]pyrimidin-7-yl)- d -leucinate for the fractalkine receptor (CX 3 CR1). Bioorg Med Chem Lett 2017; 27:2727-2730. [DOI: 10.1016/j.bmcl.2017.04.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/14/2017] [Accepted: 04/15/2017] [Indexed: 12/19/2022]
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97
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Synthesis and preliminary biological evaluation of radiolabeled 5-BDBD analogs as new candidate PET radioligands for P2X4 receptor. Bioorg Med Chem 2017; 25:3835-3844. [PMID: 28554730 DOI: 10.1016/j.bmc.2017.05.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/10/2017] [Accepted: 05/15/2017] [Indexed: 01/01/2023]
Abstract
P2X4 receptor has become an interesting molecular target for treatment and PET imaging of neuroinflammation and associated brain diseases such as Alzheimer's disease. This study reports the first design, synthesis, radiolabeling and biological evaluation of new candidate PET P2X4 receptor radioligands using 5-BDBD, a specific P2X4 receptor antagonist, as a scaffold. 5-(3-Hydroxyphenyl)-1-[11C]methyl-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one (N-[11C]Me-5-BDBD analog, [11C]9) and 5-(3-Bromophenyl)-1-[11C]methyl-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one (N-[11C]Me-5-BDBD, [11C]8c) were prepared from their corresponding desmethylated precursors with [11C]CH3OTf through N-[11C]methylation and isolated by HPLC combined with SPE in 30-50% decay corrected radiochemical yields with 370-1110GBq/µmol specific activity at EOB. 5-(3-[18F]Fluorophenyl)-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one ([18F]F-5-BDBD, [18F]5a) and 5-(3-(2-[18F]fluoroethoxy)phenyl)-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one ([18F]FE-5-BDBD, [18F]11) were prepared from their corresponding nitro- and tosylated precursors by nucleophilic substitution with K[18F]F/Kryptofix 2.2.2 and isolated by HPLC-SPE in 5-25% decay corrected radiochemical yields with 111-740GBq/µmol specific activity at EOB. The preliminary biological evaluation of radiolabeled 5-BDBD analogs indicated these new radioligands have similar biological activity with their parent compound 5-BDBD.
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98
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Lagarde J, Sarazin M, Bottlaender M. In vivo PET imaging of neuroinflammation in Alzheimer's disease. J Neural Transm (Vienna) 2017; 125:847-867. [PMID: 28516240 DOI: 10.1007/s00702-017-1731-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022]
Abstract
Increasing evidence suggests that neuroinflammation contributes to the pathophysiology of many neurodegenerative diseases, especially Alzheimer's disease (AD). Molecular imaging by PET may be a useful tool to assess neuroinflammation in vivo, thus helping to decipher the complex role of inflammatory processes in the pathophysiology of neurodegenerative diseases and providing a potential means of monitoring the effect of new therapeutic approaches. For this objective, the main target of PET studies is the 18 kDa translocator protein (TSPO), as it is overexpressed by activated microglia. In the present review, we describe the most widely used PET tracers targeting the TSPO, the methodological issues in tracer quantification and summarize the results obtained by TSPO PET imaging in AD, as well as in neurodegenerative disorders associated with AD, in psychiatric disorders and ageing. We also briefly describe alternative PET targets and imaging modalities to study neuroinflammation. Lastly, we question the meaning of PET imaging data in the context of a highly complex and multifaceted role of neuroinflammation in neurodegenerative diseases. This overview leads to the conclusion that PET imaging of neuroinflammation is a promising way of deciphering the enigma of the pathophysiology of AD and of monitoring the effect of new therapies.
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Affiliation(s)
- Julien Lagarde
- Unit of Neurology of Memory and Language, Centre de Psychiatrie et Neurosciences, INSERM UMR S894, Centre Hospitalier Sainte-Anne and Université Paris Descartes, Sorbonne Paris Cité, 75014, Paris, France
| | - Marie Sarazin
- Unit of Neurology of Memory and Language, Centre de Psychiatrie et Neurosciences, INSERM UMR S894, Centre Hospitalier Sainte-Anne and Université Paris Descartes, Sorbonne Paris Cité, 75014, Paris, France
| | - Michel Bottlaender
- UNIACT, NeuroSpin, Institut d'Imagerie Biomédicale, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique, 91191, Gif-sur-Yvette, France. .,Laboratoire Imagerie Moléculaire in Vivo, UMR 1023, Service Hospitalier Frédéric Joliot, Institut d'Imagerie Biomédicale, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique, 91400, Orsay, France.
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Han J, Liu H, Liu C, Jin H, Perlmutter JS, Egan TM, Tu Z. Pharmacologic characterizations of a P2X7 receptor-specific radioligand, [11C]GSK1482160 for neuroinflammatory response. Nucl Med Commun 2017; 38:372-382. [PMID: 28338530 PMCID: PMC5401628 DOI: 10.1097/mnm.0000000000000660] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The P2X7 receptor (P2X7R) is a key regulatory element in the neuroinflammatory cascade that provides a promising target for imaging neuroinflammation. GSK1482160, a P2X7R modulator with nanomolar binding affinity and high selectivity, has been successfully radiolabeled and utilized for imaging P2X7 levels in a mouse model of lipopolysaccharide-induced systemic inflammation. In the current study, we further characterized its binding profile and determined whether [C]GSK1482160 can detect changes in P2X7R expression in a rodent model of multiple sclerosis. METHODS [C]GSK1482160 was synthesized with high specific activity and high radiochemical purity. Radioligand saturation and competition binding assays were performed for [C]GSK1482160 using HEK293-hP2X7R living cells. Micro-PET studies were carried out in nonhuman primates. In vitro autoradiography and immunohistochemistry studies were then carried out to evaluate tracer uptake and P2X7 expression in experimental autoimmune encephalomyelitis (EAE) rat lumbar spinal cord at EAE-peak and EAE-remitting stages compared with sham rats. RESULTS [C]GSK1482160 binds to HEK293-hP2X7R living cells with high binding affinity (Kd=5.09±0.98 nmol/l, Ki=2.63±0.6 nmol/l). Micro-PET studies showed high tracer retention and a homogeneous distribution in the brain of nonhuman primates. In the EAE rat model, tracer uptake of [C]GSK1482160 in rat lumbar spinal cord was the highest at the EAE-peak stage (277.74±79.74 PSL/mm), followed by the EAE-remitting stage(149.00±54.14 PSL/mm) and sham (66.37±1.48 PSL/mm). The tracer uptake correlated strongly with P2X7-positive cell counts, activated microglia numbers, and disease severity. CONCLUSION We conclude that [C]GSK1482160 has the potential for application in monitoring neuroinflammation.
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Affiliation(s)
- Junbin Han
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hui Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chunling Liu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hongjun Jin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joel S. Perlmutter
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Neurology, Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Terrance M. Egan
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Tronel C, Largeau B, Santiago Ribeiro MJ, Guilloteau D, Dupont AC, Arlicot N. Molecular Targets for PET Imaging of Activated Microglia: The Current Situation and Future Expectations. Int J Mol Sci 2017; 18:ijms18040802. [PMID: 28398245 PMCID: PMC5412386 DOI: 10.3390/ijms18040802] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/15/2017] [Accepted: 03/28/2017] [Indexed: 12/13/2022] Open
Abstract
Microglia, as cellular mediators of neuroinflammation, are implicated in the pathogenesis of a wide range of neurodegenerative diseases. Positron emission tomography (PET) imaging of microglia has matured over the last 20 years, through the development of radiopharmaceuticals targeting several molecular biomarkers of microglial activation and, among these, mainly the translocator protein-18 kDa (TSPO). Nevertheless, current limitations of TSPO as a PET microglial biomarker exist, such as low brain density, even in a neurodegenerative setting, expression by other cells than the microglia (astrocytes, peripheral macrophages in the case of blood brain barrier breakdown), genetic polymorphism, inducing a variation for most of TSPO PET radiopharmaceuticals’ binding affinity, or similar expression in activated microglia regardless of its polarization (pro- or anti-inflammatory state), and these limitations narrow its potential interest. We overview alternative molecular targets, for which dedicated radiopharmaceuticals have been proposed, including receptors (purinergic receptors P2X7, cannabinoid receptors, α7 and α4β2 nicotinic acetylcholine receptors, adenosine 2A receptor, folate receptor β) and enzymes (cyclooxygenase, nitric oxide synthase, matrix metalloproteinase, β-glucuronidase, and enzymes of the kynurenine pathway), with a particular focus on their respective contribution for the understanding of microglial involvement in neurodegenerative diseases. We discuss opportunities for these potential molecular targets for PET imaging regarding their selectivity for microglia expression and polarization, in relation to the mechanisms by which microglia actively participate in both toxic and neuroprotective actions in brain diseases, and then take into account current clinicians’ expectations.
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Affiliation(s)
- Claire Tronel
- INSERM U930, Université François Rabelais de Tours, 10 boulevard Tonnelé, 37032 Tours, France.
| | | | - Maria Joao Santiago Ribeiro
- INSERM U930, Université François Rabelais de Tours, 10 boulevard Tonnelé, 37032 Tours, France.
- CHRU de Tours, 37044 Tours, France.
| | - Denis Guilloteau
- INSERM U930, Université François Rabelais de Tours, 10 boulevard Tonnelé, 37032 Tours, France.
- CHRU de Tours, 37044 Tours, France.
| | - Anne-Claire Dupont
- INSERM U930, Université François Rabelais de Tours, 10 boulevard Tonnelé, 37032 Tours, France.
- CHRU de Tours, 37044 Tours, France.
| | - Nicolas Arlicot
- INSERM U930, Université François Rabelais de Tours, 10 boulevard Tonnelé, 37032 Tours, France.
- CHRU de Tours, 37044 Tours, France.
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