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Simmons DA, James ML, Belichenko NP, Semaan S, Condon C, Kuan J, Shuhendler AJ, Miao Z, Chin FT, Longo FM. TSPO-PET imaging using [18F]PBR06 is a potential translatable biomarker for treatment response in Huntington's disease: preclinical evidence with the p75NTR ligand LM11A-31. Hum Mol Genet 2018; 27:2893-2912. [PMID: 29860333 PMCID: PMC6077813 DOI: 10.1093/hmg/ddy202] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder that has no cure. HD therapeutic development would benefit from a non-invasive translatable biomarker to track disease progression and treatment response. A potential biomarker is using positron emission tomography (PET) imaging with a translocator protein 18 kDa (TSPO) radiotracer to detect microglial activation, a key contributor to HD pathogenesis. The ability of TSPO-PET to identify microglial activation in HD mouse models, essential for a translatable biomarker, or therapeutic efficacy in HD patients or mice is unknown. Thus, this study assessed the feasibility of utilizing PET imaging with the TSPO tracer, [18F]PBR06, to detect activated microglia in two HD mouse models and to monitor response to treatment with LM11A-31, a p75NTR ligand known to reduce neuroinflammation in HD mice. [18F]PBR06-PET detected microglial activation in striatum, cortex and hippocampus of vehicle-treated R6/2 mice at a late disease stage and, notably, also in early and mid-stage symptomatic BACHD mice. After oral administration of LM11A-31 to R6/2 and BACHD mice, [18F]PBR06-PET discerned the reductive effects of LM11A-31 on neuroinflammation in both HD mouse models. [18F]PBR06-PET signal had a spatial distribution similar to ex vivo brain autoradiography and correlated with microglial activation markers: increased IBA-1 and TSPO immunostaining/blotting and striatal levels of cytokines IL-6 and TNFα. These results suggest that [18F]PBR06-PET is a useful surrogate marker of therapeutic efficacy in HD mice with high potential as a translatable biomarker for preclinical and clinical HD trials.
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Affiliation(s)
- Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle L James
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Sarah Semaan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Christina Condon
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Jason Kuan
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Adam J Shuhendler
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Zheng Miao
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frederick T Chin
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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Edison P, Donat CK, Sastre M. In vivo Imaging of Glial Activation in Alzheimer's Disease. Front Neurol 2018; 9:625. [PMID: 30131755 PMCID: PMC6090997 DOI: 10.3389/fneur.2018.00625] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/10/2018] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by memory loss and decline of cognitive function, associated with progressive neurodegeneration. While neuropathological processes like amyloid plaques and tau neurofibrillary tangles have been linked to neuronal death in AD, the precise role of glial activation on disease progression is still debated. It was suggested that neuroinflammation could occur well ahead of amyloid deposition and may be responsible for clearing amyloid, having a neuroprotective effect; however, later in the disease, glial activation could become deleterious, contributing to neuronal toxicity. Recent genetic and preclinical studies suggest that the different activation states of microglia and astrocytes are complex, not as polarized as previously thought, and that the heterogeneity in their phenotype can switch during disease progression. In the last few years, novel imaging techniques e.g., new radiotracers for assessing glia activation using positron emission tomography and advanced magnetic resonance imaging technologies have emerged, allowing the correlation of neuro-inflammatory markers with cognitive decline, brain function and brain pathology in vivo. Here we review all new imaging technology in AD patients and animal models that has the potential to serve for early diagnosis of the disease, to monitor disease progression and to test the efficacy and the most effective time window for potential anti-inflammatory treatments.
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Affiliation(s)
- Paul Edison
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
| | - Cornelius K Donat
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
| | - Magdalena Sastre
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom
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Metzger JM, Moore CF, Boettcher CA, Brunner KG, Fleddermann RA, Matsoff HN, Resnikoff HA, Bondarenko V, Kamp TJ, Hacker TA, Barnhart TE, Lao PJ, Christian BT, Nickles RJ, Gallagher CL, Holden JE, Emborg ME. In vivo imaging of inflammation and oxidative stress in a nonhuman primate model of cardiac sympathetic neurodegeneration. NPJ PARKINSONS DISEASE 2018; 4:22. [PMID: 30038956 PMCID: PMC6045637 DOI: 10.1038/s41531-018-0057-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 05/11/2018] [Accepted: 05/23/2018] [Indexed: 12/19/2022]
Abstract
Loss of cardiac postganglionic sympathetic innervation is a characteristic pathology of Parkinson’s disease (PD). It progresses over time independently of motor symptoms and is not responsive to typical anti-parkinsonian therapies. Cardiac sympathetic neurodegeneration can be mimicked in animals using systemic dosing of the neurotoxin 6-hydroxydopamine (6-OHDA). As in PD, 6-OHDA-induced neuronal loss is associated with increased inflammation and oxidative stress. To assess the feasibility of detecting changes over time in cardiac catecholaminergic innervation, inflammation, and oxidative stress, myocardial positron emission tomography with the radioligands [11C]meta-hydroxyephedrine (MHED), [11C]PBR28 (PBR28), and [61Cu]diacetyl-bis(N(4))-methylthiosemicarbazone (ATSM) was performed in 6-OHDA-intoxicated adult, male rhesus macaques (n = 10; 50 mg/kg i.v.). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist pioglitazone, which is known to have anti-inflammatory and anti-oxidative stress properties, was administered to five animals (5 mg/kg, PO); the other five were placebo-treated. One week after 6-OHDA, cardiac MHED uptake was significantly reduced in both groups (placebo, 86% decrease; pioglitazone, 82%); PBR28 and ATSM uptake increased in both groups but were attenuated in pioglitazone-treated animals (PBR28 Treatment × Level ANOVA p < 0.002; ATSM Mann–Whitney p = 0.032). At 12 weeks, partial recovery of MHED uptake was significantly greater in the pioglitazone-treated group, dependent on left ventricle circumferential region and axial level (Treatment × Region × Level ANOVA p = 0.034); 12-week MHED uptake significantly correlated with tyrosine hydroxylase immunoreactivity across cardiac anatomy (p < 0.000002). PBR28 and ATSM uptake returned to baseline levels by 12 weeks. These radioligands thus hold potential as in vivo biomarkers of mechanisms of cardiac neurodegeneration and neuroprotection. Three cardiac nerve loss biomarkers enable the visualization of cardiac neurodegeneration and response to neuroprotective treatment. The loss of sympathetic cardiac innervation in patients with PD causes symptoms such as postural hypotension, arrhythmia, and fatigue that do not respond to anti-parkinsonian medications. Marina Emborg and colleagues at University of Wisconsin–Madison, USA, used positron emission tomography with three radioligands to image changes in cardiac innervation, oxidative stress and inflammation in monkeys during neurotoxin-induced PD-like cardiac neurodegeneration. They were able to visualize the recruitment of inflammatory cells and increased production of reactive oxygen species during neurodegeneration as well as observe improvements in response to pioglitazone, a drug that has previously been shown to have neuroprotective effects in animal models of PD. These radioligands could be useful imaging biomarkers of cardiac nerve loss progression in patients with PD or cardiovascular disease.
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Affiliation(s)
- Jeanette M Metzger
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA.,2Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI USA
| | - Colleen F Moore
- 3Department of Psychology, University of Wisconsin-Madison, Madison, WI USA
| | - Carissa A Boettcher
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Kevin G Brunner
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Rachel A Fleddermann
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Helen N Matsoff
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Henry A Resnikoff
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Viktoriya Bondarenko
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA
| | - Timothy J Kamp
- 4Department of Medicine, University of Wisconsin-Madison, Madison, WI USA
| | - Timothy A Hacker
- 4Department of Medicine, University of Wisconsin-Madison, Madison, WI USA
| | - Todd E Barnhart
- 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
| | - Patrick J Lao
- 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
| | - Bradley T Christian
- 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
| | - R Jerry Nickles
- 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
| | | | - James E Holden
- 5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
| | - Marina E Emborg
- 1Preclinical Parkinson's Research Program, Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI USA.,2Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, WI USA.,5Department of Medical Physics, University of Wisconsin-Madison, Madison, WI USA
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105
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Expression and purification of the mammalian translocator protein for structural studies. PLoS One 2018; 13:e0198832. [PMID: 29897975 PMCID: PMC5999236 DOI: 10.1371/journal.pone.0198832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 05/26/2018] [Indexed: 11/19/2022] Open
Abstract
The translocator protein (TSPO) is an 18 kDa polytopic membrane protein of the outer mitochondrial membrane, abundantly present in the steroid-synthesising cells. TSPO has been linked to a number of disorders, and it is recognised as a promising drug target with a range of potential medical applications. Structural and biochemical characterisation of a mammalian TSPO requires expression and purification of the protein of high quality in sufficiently large quantities. Here we describe detailed procedures for heterologous expression and purification of mammalian TSPO in HEK293 cells. We demonstrate that the established procedures can be used for untagged TSPO as well as for C-terminally fused TSPO constructs. Our protocol can be routinely used to generate high-quality TSPO preparations for biochemical and structural studies.
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Abstract
PURPOSE OF REVIEW To present the new PET markers that could become in the coming years, relevant to advanced clinical approaches to dementia diagnosis, drug trials, and treatment strategies and discuss their advantages and limitations. RECENT FINDINGS The most advanced new PET tracers are the markers of the amyloid plaques, the τ compounds and the tracers of the translocator protein as markers of neuroinflammation. The main advantages but also the weaknesses of each of these markers are discussed. The main pitfall remains the heterogeneity of the available results that cast doubt to a rapid introduction of these new ligands in clinical practice. SUMMARY With the advent of biomarkers in clinical management and findings of molecular neuroimaging studies in the evaluation of patients with suspected dementia, the impact of functional neuroimaging has increased considerably these last years and has been integrated into many clinical guidelines in the field of dementia. In addition to conventional single PET brain perfusion and dopaminergic neurotransmission, 18F-fluorodeoxyglucose (18F-FDG) PET is used in advanced diagnosis procedures. Furthermore, new tracers are being developed to quantify key neuropathological features in the brain tissue as highly specific diagnosis is crucial to comply with the global medical and public health objectives in this domain. A strategic road map for further developments, adapted from the approach to cancer biomarkers, should be proposed so as to optimize the rationale of the PET-based molecular diagnosis of Alzheimer's disease and related disorders.
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107
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Dupont AC, Largeau B, Guilloteau D, Santiago Ribeiro MJ, Arlicot N. The Place of PET to Assess New Therapeutic Effectiveness in Neurodegenerative Diseases. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:7043578. [PMID: 29887768 PMCID: PMC5985069 DOI: 10.1155/2018/7043578] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/01/2018] [Indexed: 12/16/2022]
Abstract
In vivo exploration of neurodegenerative diseases by positron emission tomography (PET) imaging has matured over the last 20 years, using dedicated radiopharmaceuticals targeting cellular metabolism, neurotransmission, neuroinflammation, or abnormal protein aggregates (beta-amyloid and intracellular microtubule inclusions containing hyperphosphorylated tau). The ability of PET to characterize biological processes at the cellular and molecular levels enables early detection and identification of molecular mechanisms associated with disease progression, by providing accurate, reliable, and longitudinally reproducible quantitative biomarkers. Thus, PET imaging has become a relevant imaging method for monitoring response to therapy, approved as an outcome measure in bioclinical trials. The aim of this paper is to review and discuss the current inputs of PET in the assessment of therapeutic effectiveness in neurodegenerative diseases connected by common pathophysiological mechanisms, including Parkinson's disease, Huntington's disease, dementia, amyotrophic lateral sclerosis, multiple sclerosis, and also in psychiatric disorders. We also discuss opportunities for PET imaging to drive more personalized neuroprotective and therapeutic strategies, taking into account individual variability, within the growing framework of precision medicine.
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Affiliation(s)
- Anne-Claire Dupont
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
- CHRU de Tours, Unité de Radiopharmacie, Tours, France
| | | | - Denis Guilloteau
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
- CHRU de Tours, Service de Médecine Nucléaire in vitro, Tours, France
- INSERM CIC 1415, University Hospital, Tours, France
| | - Maria Joao Santiago Ribeiro
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
- INSERM CIC 1415, University Hospital, Tours, France
- CHRU de Tours, Service de Médecine Nucléaire in vivo, Tours, France
| | - Nicolas Arlicot
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
- CHRU de Tours, Unité de Radiopharmacie, Tours, France
- INSERM CIC 1415, University Hospital, Tours, France
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108
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Translocator protein (18kDa TSPO) binding, a marker of microglia, is reduced in major depression during cognitive-behavioral therapy. Prog Neuropsychopharmacol Biol Psychiatry 2018; 83:1-7. [PMID: 29269262 DOI: 10.1016/j.pnpbp.2017.12.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/27/2017] [Accepted: 12/18/2017] [Indexed: 12/27/2022]
Abstract
Prior studies indicated that neuroinflammation might play a role in the pathophysiology of major depressive disorder (MDD). The purpose of this study was to examine changes in a microglial marker in the brain of patients with MDD during cognitive-behavioral therapy (CBT) and supportive psychotherapy (SPT). Participants were newly diagnosed patients with MDD receiving CBT (n=20) or SPT (n=20) who were compared with 20 healthy control subjects. We used [18F]-FEPPA positron emission tomography (PET) to examine translocator protein total distribution volume (TSPO VT), a marker of microglial density and inflammation. Patients were scanned before and after CBT and SPT. Before therapy, TSPO VT was significantly elevated in neocortical grey matter, frontal cortex, temporal cortex, and hippocampus in MDD relative to the control subjects. In the CBT group, but not in the SPT group, TSPO VT was significantly reduced during the treatment period. Reductions in TSPO VT were correlated with the amelioration of depressive symptoms. This correlation was consistent in the hippocampus in both CBT and SPT groups. In conclusion, CBT, when it reduced symptoms, also decreased TSPO VT. Efficient psychosocial interventions were accompanied by the normalization of a glial marker in the brain of patients with MDD, which may indicate reduced pro-inflammatory activity.
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109
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Zinnhardt B, Wiesmann M, Honold L, Barca C, Schäfers M, Kiliaan AJ, Jacobs AH. In vivo imaging biomarkers of neuroinflammation in the development and assessment of stroke therapies - towards clinical translation. Theranostics 2018; 8:2603-2620. [PMID: 29774062 PMCID: PMC5956996 DOI: 10.7150/thno.24128] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/31/2018] [Indexed: 01/01/2023] Open
Abstract
Modulation of the inflammatory microenvironment after stroke opens a new avenue for the development of novel neurorestorative therapies in stroke. Understanding the spatio-temporal profile of (neuro-)inflammatory imaging biomarkers in detail thereby represents a crucial factor in the development and application of immunomodulatory therapies. The early integration of quantitative molecular imaging biomarkers in stroke drug development may provide key information about (i) early diagnosis and follow-up, (ii) spatio-temporal drug-target engagement (pharmacodynamic biomarker), (iii) differentiation of responders and non-responders in the patient cohort (inclusion/exclusion criteria; predictive biomarkers), and (iv) the mechanism of action. The use of targeted imaging biomarkers for may thus allow clinicians to decipher the profile of patient-specific inflammatory activity and the development of patient-tailored strategies for immunomodulatory and neuro-restorative therapies in stroke. Here, we highlight the recent developments in preclinical and clinical molecular imaging biomarkers of neuroinflammation (endothelial markers, microglia, MMPs, cell labeling, future developments) in stroke and outline how imaging biomarkers can be used in overcoming current translational roadblocks and attrition in order to advance new immunomodulatory compounds within the clinical pipeline.
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Affiliation(s)
- Bastian Zinnhardt
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
- EU 7 th FP Programme “Imaging Inflammation in Neurodegenerative Diseases (INMiND)”
- Cells in Motion (CiM) Cluster of Excellence, University of Münster, Münster, Germany
- PET Imaging in Drug Design and Development (PET3D)
- Department of Nuclear Medicine, Universitätsklinikum Münster, Münster, Germany
| | - Maximilian Wiesmann
- Department of Anatomy, Radboud university medical center, Donders Institute for Brain, Cognition & Behaviour, Nijmegen, The Netherlands
| | - Lisa Honold
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
| | - Cristina Barca
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
- PET Imaging in Drug Design and Development (PET3D)
| | - Michael Schäfers
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
- Cells in Motion (CiM) Cluster of Excellence, University of Münster, Münster, Germany
- Department of Nuclear Medicine, Universitätsklinikum Münster, Münster, Germany
| | - Amanda J Kiliaan
- Department of Anatomy, Radboud university medical center, Donders Institute for Brain, Cognition & Behaviour, Nijmegen, The Netherlands
| | - Andreas H Jacobs
- European Institute for Molecular Imaging (EIMI), Westfälische Wilhelms University Münster, Münster, Germany
- EU 7 th FP Programme “Imaging Inflammation in Neurodegenerative Diseases (INMiND)”
- Cells in Motion (CiM) Cluster of Excellence, University of Münster, Münster, Germany
- PET Imaging in Drug Design and Development (PET3D)
- Department of Geriatrics, Johanniter Hospital, Evangelische Kliniken, Bonn, Germany
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Wei L, Syed Mortadza SA, Yan J, Zhang L, Wang L, Yin Y, Li C, Chalon S, Emond P, Belzung C, Li D, Lu C, Roger S, Jiang LH. ATP-activated P2X7 receptor in the pathophysiology of mood disorders and as an emerging target for the development of novel antidepressant therapeutics. Neurosci Biobehav Rev 2018; 87:192-205. [PMID: 29453990 DOI: 10.1016/j.neubiorev.2018.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 02/01/2018] [Accepted: 02/08/2018] [Indexed: 12/11/2022]
Abstract
Mood disorders are a group of psychiatric conditions that represent leading global disease burdens. Increasing evidence from clinical and preclinical studies supports that innate immune system dysfunction plays an important part in the pathophysiology of mood disorders. P2X7 receptor, belonging to the ligand-gated ion channel P2X subfamily of purinergic P2 receptors for extracellular ATP, is highly expressed in immune cells including microglia in the central nervous system (CNS) and has a vital role in mediating innate immune response. The P2X7 receptor is also important in neuron-glia signalling in the CNS. The gene encoding human P2X7 receptor is located in a locus of susceptibility to mood disorders. In this review, we will discuss the recent progress in understanding the role of the P2X7 receptor in the pathogenesis and development of mood disorders and in discovering CNS-penetrable P2X7 antagonists for potential uses in in vivo imaging to monitor brain inflammation and antidepressant therapeutics.
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Affiliation(s)
- Linyu Wei
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom
| | - Sharifah A Syed Mortadza
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom; Faculty of Medicine and Health Science, University Putra Malaysia, Selangor, Malaysia
| | - Jing Yan
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Libin Zhang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Lu Wang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Yaling Yin
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Chaokun Li
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China
| | - Sylvie Chalon
- Inserm UMR 1253, iBrain, Université de Tours, Tours, France
| | - Patrick Emond
- Inserm UMR 1253, iBrain, Université de Tours, Tours, France; CHRU de Tours, Service de Médecine Nucléaire In Vitro, Tours, France
| | | | - Dongliang Li
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; Key Laboratory for the Brain Research of Henan Province, Xinxiang Medical University, China
| | - Chengbiao Lu
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; Key Laboratory for the Brain Research of Henan Province, Xinxiang Medical University, China
| | - Sebastien Roger
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université de Tours, France; Institut Universitaire de France, Paris Cedex 05, France
| | - Lin-Hua Jiang
- Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Xinxiang Medical University, China; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom; Institut Universitaire de France, Paris Cedex 05, France.
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111
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Biswas L, Zhou X, Dhillon B, Graham A, Shu X. Retinal pigment epithelium cholesterol efflux mediated by the 18 kDa translocator protein, TSPO, a potential target for treating age-related macular degeneration. Hum Mol Genet 2018; 26:4327-4339. [PMID: 28973423 DOI: 10.1093/hmg/ddx319] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 08/06/2017] [Indexed: 12/13/2022] Open
Abstract
Cholesterol accumulation beneath the retinal pigment epithelium (RPE) cells is supposed to contribute the pathogenesis of age-related macular degeneration (AMD). Cholesterol efflux genes (APOE and ABCA1) were identified as risk factors for AMD, although how cholesterol efflux influences accumulation of this lipid in sub-RPE deposits remains elusive. The 18 kDa translocator protein, TSPO, is a cholesterol-binding protein implicated in mitochondrial cholesterol transport. Here, we investigate the function of TSPO in cholesterol efflux from the RPE cells. We demonstrate in RPE cells that TSPO specific ligands promoted cholesterol efflux to acceptor (apo)lipoprotein and human serum, while loss of TSPO resulted in impaired cholesterol efflux. TSPO-/- RPE cells also had significantly increased production of reactive oxygen species (ROS) and upregulated expression of proinflammatory cytokines (IL-1β and TNFα). Cholesterol (oxidized LDL) uptake and accumulation were markedly increased in TSPO-/- RPE cells. Finally, in aged RPE cells, TSPO expression was reduced and cholesterol efflux impaired. These findings provide a new pharmacological concept to treat early AMD patients by stimulating cellular cholesterol removal with TSPO specific ligands or by overexpression of TSPO in RPE cells.
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Affiliation(s)
- Lincoln Biswas
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xinzhi Zhou
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Baljean Dhillon
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16?4SB, UK
| | - Annette Graham
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
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112
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Berroterán-Infante N, Balber T, Fürlinger P, Bergmann M, Lanzenberger R, Hacker M, Mitterhauser M, Wadsak W. [ 18F]FEPPA: Improved Automated Radiosynthesis, Binding Affinity, and Preliminary in Vitro Evaluation in Colorectal Cancer. ACS Med Chem Lett 2018. [PMID: 29541356 DOI: 10.1021/acsmedchemlett.7b00367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The overexpression of the translocator protein (TSPO) has been amply reported for a variety of conditions, including neurodegenerative disorders, heart failure, and cancer. Thus, TSPO has been proposed as an excellent imaging biomarker, allowing, in this manner, to obtain an accurate diagnosis and to follow disease progression and therapy response. Accordingly, several radioligands have been developed to accomplish this purpose. In this work, we selected [18F]FEPPA, as one of the clinical established tracers, and assessed its in vitro performance in colorectal cancer. Moreover, we setup an improved radiosynthesis method and assessed the in vitro binding affinity of the nonradioactive ligand toward the human TSPO. Our results show an excellent to moderate affinity, in the subnanomolar and nanomolar range, as well as the suitability of [18F]FEPPA as an imaging agent for the TSPO in colorectal cancer.
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Affiliation(s)
- Neydher Berroterán-Infante
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
- Department of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna A-1090, Austria
| | - Theresa Balber
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
- Department of Pharmaceutical Technology, Faculty of Life Sciences, University of Vienna, Vienna A-1090, Austria
| | - Petra Fürlinger
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
| | - Michael Bergmann
- Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna A-1090, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna A-1090, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
| | - Markus Mitterhauser
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
- Department of Pharmaceutical Technology, Faculty of Life Sciences, University of Vienna, Vienna A-1090, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, Vienna A-1090, Austria
| | - Wolfgang Wadsak
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna A-1090, Austria
- Department of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Vienna A-1090, Austria
- Center for Biomarker Research in Medicine, CBmed GmbH, Graz A-8010, Austria
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113
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Tang D, Fujinaga M, Hatori A, Zhang Y, Yamasaki T, Xie L, Mori W, Kumata K, Liu J, Manning HC, Huang G, Zhang MR. Evaluation of the novel TSPO radiotracer 2-(7-butyl-2-(4-(2-([ 18F]fluoroethoxy)phenyl)-5-methylpyrazolo[1,5-a]pyrimidin-3-yl)-N,N-diethylacetamide in a preclinical model of neuroinflammation. Eur J Med Chem 2018; 150:1-8. [PMID: 29505933 DOI: 10.1016/j.ejmech.2018.02.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 12/13/2022]
Abstract
Translocator Protein (18 kDa, TSPO) is regarded as a useful biomarker for neuroinflammation imaging. TSPO PET imaging could be used to understand the role of neuroinflammation in brain diseases and as a tool for evaluating novel therapeutic effects. As a promising TSPO probe, [18F]DPA-714 is highly specific and offers reliable quantification of TSPO in vivo. In this study, we further radiosynthesized and evaluated another novel TSPO probe, 2-(7-butyl-2-(4-(2-[18F]fluoroethoxy)phenyl)-5-methylpyrazolo[1,5-a]pyrimidin-3-yl)-N,N-diethylacetamide ([18F]VUIIS1018A), which features a 700-fold higher binding affinity for TSPO than that of [18F]DPA-714. We evaluated the performance of [18F]VUIIS1018A using dynamic in vivo PET imaging, radiometabolite analysis, in vitro autoradiography assays, biodistribution analysis, and blocking assays. In vivo study using this probe demonstrated high signal-to-noise ratio, binding potential (BPND), and binding specificity in preclinical neuroinflammation studies. Taken together, these findings indicate that [18F]VUIIS1018A may serve as a novel TSPO PET probe for neuroinflammation imaging.
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Affiliation(s)
- Dewei Tang
- Shanghai Key Laboratory for Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China; Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China; Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Akiko Hatori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Yiding Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Lin Xie
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Wakana Mori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Katsushi Kumata
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Jianjun Liu
- Shanghai Key Laboratory for Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China; Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pu Jian Road, Shanghai 200127, China; Institute of Clinical Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - H Charles Manning
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Gang Huang
- Shanghai Key Laboratory for Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China; Institute of Clinical Nuclear Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine (SJTUSM) & Shanghai Institute for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai 200025, China.
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Science, National Institute for Quantum and Radiological Science and Technology, Chiba, Japan.
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114
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Donat CK, Mirzaei N, Tang SP, Edison P, Sastre M. Imaging of Microglial Activation in Alzheimer's Disease by [ 11C]PBR28 PET. Methods Mol Biol 2018; 1750:323-339. [PMID: 29512083 DOI: 10.1007/978-1-4939-7704-8_22] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Deficits in neuronal function and synaptic plasticity in Alzheimer's disease (AD) are believed to be linked to microglial activation. A hallmark of reactive microglia is the upregulation of mitochondrial translocator protein (TSPO) expression. Positron emission tomography (PET) is a nuclear imaging technique that measures the distribution of trace doses of radiolabeled compounds in the body over time. PET imaging using the 2nd generation TSPO tracer [11C]PBR28 provides an opportunity for accurate visualization and quantification of changes in microglial density in transgenic mouse models of Alzheimer's disease (AD). Here, we describe the methodology for the in vivo use of [11C]PBR28 in AD patients and the 5XFAD transgenic mouse model of AD and compare the results against healthy individuals and wild-type controls. To confirm the results, autoradiography with [3H]PBR28 and immunochemistry was carried out in the same mouse brains. Our data shows that [11C]PBR28 is suitable as a tool for in vivo monitoring of microglial activation and may be useful to assess treatment response in future studies.
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Affiliation(s)
- Cornelius K Donat
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Nazanin Mirzaei
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | | | - Paul Edison
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Magdalena Sastre
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK.
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115
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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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116
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Pulagam KR, Colás L, Padro D, Plaza-García S, Gómez-Vallejo V, Higuchi M, Llop J, Martín A. Evaluation of the novel TSPO radiotracer [ 18F] VUIIS1008 in a preclinical model of cerebral ischemia in rats. EJNMMI Res 2017; 7:93. [PMID: 29177913 PMCID: PMC5701906 DOI: 10.1186/s13550-017-0343-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/12/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND In vivo positron-emission tomography (PET) imaging of transporter protein (TSPO) expression is an attractive and indispensable tool for the diagnosis and therapy evaluation of neuroinflammation after cerebral ischemia. Despite several radiotracers have shown an excellent capacity to image neuroinflammation, novel radiotracers such as [18F] VUIIS1008 have shown promising properties to visualize and quantify the in vivo expression of TSPO. METHODS Longitudinal in vivo magnetic resonance (MRI) and PET imaging studies with the novel TSPO radiotracer 2-(5,7-diethyl-2-(4-(2-[18F] fluoroethoxy) phenyl) pyrazolo [1,5-a] pyrimidin-3-yl)-N, N-diethylacetamide ([18F] VUIIS1008), and (N, N-diethyl-2-(2-[4-(2-fluoroethoxy)-phenyl]-5,7-dimethyl-pyrazolo [1,5-a] yrimidin-3-yl)-acetamide ([18F] DPA-714) were carried out before and at days 1, 3, 7, 14, 21, and 28 following the transient middle cerebral artery occlusion (MCAO) in rats. RESULTS MRI images showed the extension and evolution of the brain infarction after ischemic stroke in rats. PET imaging with [18F] VUIIS1008 and [18F] DPA714 showed a progressive increase in the ischemic brain hemisphere during the first week, peaking at day 7 and followed by a decline from days 14 to 28 after cerebral ischemia. [18F] DPA714 uptake showed a mild uptake increase compared to [18F] VUIIS1008 in TSPO-rich ischemic brain regions. In vivo [18F] VUIIS1008 binding displacement with VUIIS1008 was more efficient than DPA714. Finally, immunohistochemistry confirmed a high expression of TSPO in microglial cells at day 7 after the MCAO in rats. CONCLUSIONS Altogether, these results suggest that [18F] VUIIS1008 could become a valuable tool for the diagnosis and treatment evaluation of neuroinflammation following ischemic stroke.
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Affiliation(s)
- Krishna R Pulagam
- Radiochemistry and Nuclear Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Lorena Colás
- Experimental Molecular Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Daniel Padro
- Magnetic Resonance Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Sandra Plaza-García
- Magnetic Resonance Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Vanessa Gómez-Vallejo
- Radiochemistry and Nuclear Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Makoto Higuchi
- National Institutes for Quantum and Radiological Science and Technology, National Institute of Radiological Sciences, Chiba, Japan
| | - Jordi Llop
- Radiochemistry and Nuclear Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain
| | - Abraham Martín
- Experimental Molecular Imaging, Molecular Imaging Unit, CIC biomaGUNE, P° Miramon 182, San Sebastian, Spain.
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117
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Regulation of Mitochondrial, Cellular, and Organismal Functions by TSPO. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:103-136. [PMID: 29413517 DOI: 10.1016/bs.apha.2017.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In 1999, the enigma of the 18kDa mitochondrial translocator protein (TSPO), also known as the peripheral-type benzodiazepine receptor, was the seeming disparity of the many functions attributed to TSPO, ranging from the potential of TSPO acting as a housekeeping gene at molecular biological levels to adaptations to stress, and even involvement in higher emotional and cognitive functioning, such as anxiety and depression. In the years since then, knowledge regarding the many functions modulated by TSPO has expanded, and understanding has deepened. In addition, new functions could be firmly associated with TSPO, such as regulation of programmed cell death and modulation of gene expression. Interestingly, control by the mitochondrial TSPO over both of these life and death functions appears to include Ca++ homeostasis, generation of reactive oxygen species (ROS), and ATP production. Other mitochondrial functions under TSPO control are considered to be steroidogenesis and tetrapyrrole metabolism. As TSPO effects on gene expression and on programmed cell death can be related to the wide range of functions that can be associated with TSPO, several of these five elements of Ca++, ROS, ATP, steroids, and tetrapyrroles may indeed form the basis of TSPO's capability to operate as a multifunctional housekeeping gene to maintain homeostasis of the cell and of the whole multicellular organism.
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118
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Abstract
A compelling need in the field of neurodegenerative diseases is the development and validation of biomarkers for early identification and differential diagnosis. The availability of positron emission tomography (PET) neuroimaging tools for the assessment of molecular biology and neuropathology has opened new venues in the diagnostic design and the conduction of new clinical trials. PET techniques, allowing the in vivo assessment of brain function and pathology changes, are increasingly showing great potential in supporting clinical diagnosis also in the early and even preclinical phases of dementia. This review will summarize the most recent evidence on fluorine-18 fluorodeoxyglucose-, amyloid -, tau -, and neuroinflammation - PET tools, highlighting strengths and limitations and possible new perspectives in research and clinical applications. Appropriate use of PET tools is crucial for a prompt diagnosis and target evaluation of new developed drugs aimed at slowing or preventing dementia.
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Affiliation(s)
- Leonardo Iaccarino
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Arianna Sala
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Silvia Paola Caminiti
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Daniela Perani
- Vita-Salute San Raffaele University, Milan, Italy.,In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.,Nuclear Medicine Unit, IRCCS San Raffaele Hospital, Milan, Italy
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119
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Staffaroni AM, Elahi FM, McDermott D, Marton K, Karageorgiou E, Sacco S, Paoletti M, Caverzasi E, Hess CP, Rosen HJ, Geschwind MD. Neuroimaging in Dementia. Semin Neurol 2017; 37:510-537. [PMID: 29207412 PMCID: PMC5823524 DOI: 10.1055/s-0037-1608808] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Although the diagnosis of dementia still is primarily based on clinical criteria, neuroimaging is playing an increasingly important role. This is in large part due to advances in techniques that can assist with discriminating between different syndromes. Magnetic resonance imaging remains at the core of differential diagnosis, with specific patterns of cortical and subcortical changes having diagnostic significance. Recent developments in molecular PET imaging techniques have opened the door for not only antemortem but early, even preclinical, diagnosis of underlying pathology. This is vital, as treatment trials are underway for pharmacological agents with specific molecular targets, and numerous failed trials suggest that earlier treatment is needed. This article provides an overview of classic neuroimaging findings as well as new and cutting-edge research techniques that assist with clinical diagnosis of a range of dementia syndromes, with an emphasis on studies using pathologically proven cases.
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Affiliation(s)
- Adam M. Staffaroni
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
| | - Fanny M. Elahi
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
| | - Dana McDermott
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
| | - Kacey Marton
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
| | - Elissaios Karageorgiou
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
- Neurological Institute of Athens, Athens, Greece
| | - Simone Sacco
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
- Institute of Radiology, Department of Clinical Surgical Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Matteo Paoletti
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
- Institute of Radiology, Department of Clinical Surgical Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Eduardo Caverzasi
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Christopher P. Hess
- Division of Neuroradiology, Department of Radiology, University of California, San Francisco (UCSF), California
| | - Howard J. Rosen
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
| | - Michael D. Geschwind
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California
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120
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TSPO PET Imaging: From Microglial Activation to Peripheral Sterile Inflammatory Diseases? CONTRAST MEDIA & MOLECULAR IMAGING 2017; 2017:6592139. [PMID: 29114179 PMCID: PMC5632884 DOI: 10.1155/2017/6592139] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/01/2017] [Accepted: 08/07/2017] [Indexed: 02/07/2023]
Abstract
Peripheral sterile inflammatory diseases (PSIDs) are a heterogeneous group of disorders that gathers several chronic insults involving the cardiovascular, respiratory, gastrointestinal, or musculoskeletal system and wherein inflammation is the cornerstone of the pathophysiology. In PSID, timely characterization and localization of inflammatory foci are crucial for an adequate care for patients. In brain diseases, in vivo positron emission tomography (PET) exploration of inflammation has matured over the last 20 years, through the development of radiopharmaceuticals targeting the translocator protein-18 kDa (TSPO) as molecular biomarkers of activated microglia. Recently, TSPO has been introduced as a possible molecular target for PSIDs PET imaging, making this protein a potential biomarker to address disease heterogeneity, to assist in patient stratification, and to contribute to predicting treatment response. In this review, we summarized the major research advances recently made in the field of TSPO PET imaging in PSIDs. Promising preliminary results have been reported in bowel, cardiovascular, and rheumatic inflammatory diseases, consolidated by preclinical studies. Limitations of TSPO PET imaging in PSIDs, regarding both its large expression in healthy peripheral tissues, unlike in central nervous system, and the production of peripheral radiolabeled metabolites, are also discussed, regarding their possible consequences on TSPO PET signal's quantification.
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121
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Heurling K, Leuzy A, Jonasson M, Frick A, Zimmer ER, Nordberg A, Lubberink M. Quantitative positron emission tomography in brain research. Brain Res 2017; 1670:220-234. [PMID: 28652218 DOI: 10.1016/j.brainres.2017.06.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 12/21/2022]
Abstract
The application of positron emission tomography (PET) in brain research has increased substantially during the past 20years, and is still growing. PET provides a unique insight into physiological and pathological processes in vivo. In this article we introduce the fundamentals of PET, and the methods available for acquiring quantitative estimates of the parameters of interest. A short introduction to different areas of application is also given, including basic research of brain function and in neurology, psychiatry, drug receptor occupancy studies, and its application in diagnostics of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Our aim is to inform the unfamiliar reader of the underlying basics and potential applications of PET, hoping to inspire the reader into considering how the technique could be of benefit for his or her own research.
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Affiliation(s)
- Kerstin Heurling
- Wallenberg Centre for Molecular and Translational Medicine and the Department of Psychiatry and Neurochemistry, University of Gothenburg, Sweden; Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
| | - Antoine Leuzy
- Department Neurobiology, Care Sciences and Society, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - My Jonasson
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | - Andreas Frick
- Department of Psychology, Uppsala University, Uppsala, Sweden; Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Eduardo R Zimmer
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; Brain Institute of Rio Grande do Sul (BraIns), Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Agneta Nordberg
- Department Neurobiology, Care Sciences and Society, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Stockholm, Sweden; Department of Geriatric Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Mark Lubberink
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Medical Physics, Uppsala University Hospital, Uppsala, Sweden
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122
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Fujinaga M, Luo R, Kumata K, Zhang Y, Hatori A, Yamasaki T, Xie L, Mori W, Kurihara Y, Ogawa M, Nengaki N, Wang F, Zhang MR. Development of a 18F-Labeled Radiotracer with Improved Brain Kinetics for Positron Emission Tomography Imaging of Translocator Protein (18 kDa) in Ischemic Brain and Glioma. J Med Chem 2017; 60:4047-4061. [PMID: 28422499 DOI: 10.1021/acs.jmedchem.7b00374] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We designed four novel acetamidobenzoxazolone compounds 7a-d as candidates for positron emission tomography (PET) radiotracers for imaging the translocator protein (18 kDa, TSPO) in ischemic brain and glioma. Among these compounds, 2-(5-(6-fluoropyridin-3-yl)-2-oxobenzo[d]oxazol-3(2H)-yl)-N-methyl-N-phenylacetamide (7d) exhibited high binding affinity (Ki = 13.4 nM) with the TSPO and moderate lipophilicity (log D = 1.92). [18F]7d was radiosynthesized by [18F]fluorination of the bromopyridine precursor 7h with [18F]F- in 12 ± 5% radiochemical yield (n = 6, decay-corrected). In vitro autoradiography and PET studies of ischemic rat brain revealed higher binding of [18F]7d with TSPO on the ipsilateral side, as compared to the contralateral side, and improved brain kinetics compared with our previously developed radiotracers. Metabolite study of [18F]7d showed 93% of unchanged form in the ischemic brain at 30 min after injection. Moreover, PET study with [18F]7d provided a clear tumor image in a glioma-bearing rat model. We demonstrated that [18F]7d is a useful PET radiotracer for visualizing not only neuroinflammation but also glioma and will translate this radiotracer to a "first-in-human" study in our facility.
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Affiliation(s)
- Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Rui Luo
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University , 68 Chanle Road, Nanjing 210006, China
| | - Katsushi Kumata
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yiding Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Akiko Hatori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Lin Xie
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Wakana Mori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yusuke Kurihara
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.,SHI Accelerator Service Co. , 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Masanao Ogawa
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.,SHI Accelerator Service Co. , 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Nobuki Nengaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.,SHI Accelerator Service Co. , 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Feng Wang
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University , 68 Chanle Road, Nanjing 210006, China
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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