1
|
Lee N, Choi JY, Ryu YH. The development status of PET radiotracers for evaluating neuroinflammation. Nucl Med Mol Imaging 2024; 58:160-176. [PMID: 38932754 PMCID: PMC11196502 DOI: 10.1007/s13139-023-00831-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/16/2023] [Accepted: 12/05/2023] [Indexed: 06/28/2024] Open
Abstract
Neuroinflammation is associated with the pathophysiologies of neurodegenerative and psychiatric disorders. Evaluating neuroinflammation using positron emission tomography (PET) plays an important role in the early diagnosis and determination of proper treatment of brain diseases. To quantify neuroinflammatory responses in vivo, many PET tracers have been developed using translocator proteins, imidazole-2 binding site, cyclooxygenase, monoamine oxidase-B, adenosine, cannabinoid, purinergic P2X7, and CSF-1 receptors as biomarkers. In this review, we introduce the latest developments in PET tracers that can image neuroinflammation, focusing on clinical trials, and further consider their current implications.
Collapse
Affiliation(s)
- Namhun Lee
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
| | - Jae Yong Choi
- Division of Applied RI, Korea Institute of Radiological & Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 01812 Korea
- Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| |
Collapse
|
2
|
Singhal T, Cicero S, Rissanen E, Ficke J, Kukreja P, Vaquerano S, Glanz B, Dubey S, Sticka W, Seaver K, Kijewski M, Callen AM, Chu R, Carter K, Silbersweig D, Chitnis T, Bakshi R, Weiner HL. Glial Activity Load on PET Reveals Persistent "Smoldering" Inflammation in MS Despite Disease-Modifying Treatment: 18 F-PBR06 Study. Clin Nucl Med 2024; 49:491-499. [PMID: 38630948 DOI: 10.1097/rlu.0000000000005201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
PURPOSE OF THE REPORT 18 F-PBR06-PET targeting 18-kDa translocator protein can detect abnormal microglial activation (MA) in multiple sclerosis (MS). The objectives of this study are to develop individualized mapping of MA using 18 F-PBR06, to determine the effect of disease-modifying treatment (DMT) efficacy on reducing MA, and to determine its clinical, radiological, and serological correlates in MS patients. PATIENTS AND METHODS Thirty 18 F-PBR06-PET scans were performed in 22 MS patients (mean age, 46 ± 13 years; 16 females) and 8 healthy controls (HCs). Logarithmically transformed "glial activity load on PET" scores (calculated as the sum of voxel-by-voxel z -scores ≥4), "lnGALP," were compared between MS and HC and between MS subjects on high-efficacy DMTs (H-DMT, n = 13) and those on no or lower-efficacy treatment, and correlated with clinical measures, serum biomarkers, and cortical thickness. RESULTS Cortical gray matter (CoGM) and white matter (WM) lnGALP scores were higher in MS versus HC (+33% and +48%, P < 0.001). In H-DMT group, CoGM and WM lnGALP scores were significantly lower than lower-efficacy treatment ( P < 0.01) but remained abnormally higher than in HC group ( P = 0.006). Within H-DMT patients, CoGM lnGALP scores correlated positively with physical disability, fatigue and serum glial fibrillary acid protein levels ( r = 0.65-0.79, all P 's < 0.05), and inversely with cortical thickness ( r = -0.66, P < 0.05). CONCLUSIONS High-efficacy DMTs decrease, but do not normalize, CoGM and WM MA in MS patients. Such "residual" MA in CoGM is associated with clinical disability, serum biomarkers, and cortical degeneration. Individualized mapping of translocator protein PET using 18 F-PBR06 is clinically feasible and can potentially serve as an imaging biomarker for evaluating "smoldering" inflammation in MS patients.
Collapse
Affiliation(s)
| | - Steven Cicero
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - Eero Rissanen
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - John Ficke
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - Preksha Kukreja
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - Steven Vaquerano
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - Bonnie Glanz
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| | - Shipra Dubey
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology
| | - William Sticka
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology
| | - Kyle Seaver
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology
| | - Marie Kijewski
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology
| | - Alexis M Callen
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| | - Renxin Chu
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| | - Kelsey Carter
- From the Department of Neurology, PET Imaging Program in Neurologic Diseases
| | - David Silbersweig
- Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Tanuja Chitnis
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| | - Rohit Bakshi
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| | - Howard L Weiner
- Department of Neurology, Brigham Multiple Sclerosis Center, Ann Romney Center for Neurologic Diseases
| |
Collapse
|
3
|
Cools R, Kerkhofs K, Leitao RCF, Bormans G. Preclinical Evaluation of Novel PET Probes for Dementia. Semin Nucl Med 2023; 53:599-629. [PMID: 37149435 DOI: 10.1053/j.semnuclmed.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/24/2023] [Indexed: 05/08/2023]
Abstract
The development of novel PET imaging agents that selectively bind specific dementia-related targets can contribute significantly to accurate, differential and early diagnosis of dementia causing diseases and support the development of therapeutic agents. Consequently, in recent years there has been a growing body of literature describing the development and evaluation of potential new promising PET tracers for dementia. This review article provides a comprehensive overview of novel dementia PET probes under development, classified by their target, and pinpoints their preclinical evaluation pathway, typically involving in silico, in vitro and ex/in vivo evaluation. Specific target-associated challenges and pitfalls, requiring extensive and well-designed preclinical experimental evaluation assays to enable successful clinical translation and avoid shortcomings observed for previously developed 'well-established' dementia PET tracers are highlighted in this review.
Collapse
Affiliation(s)
- Romy Cools
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Kobe Kerkhofs
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; NURA, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Renan C F Leitao
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium.
| |
Collapse
|
4
|
Rapid Purification and Formulation of Radiopharmaceuticals via Thin-Layer Chromatography. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238178. [PMID: 36500272 PMCID: PMC9738419 DOI: 10.3390/molecules27238178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/25/2022]
Abstract
Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g., semi-preparative radio-HPLC) to ensure adequate purity of the radiopharmaceutical. Due to the use of organic solvents during purification, additional processing is needed to reformulate the radiopharmaceutical into an injectable buffer. Recent developments in microscale radiosynthesis have made it possible to synthesize radiopharmaceuticals with vastly reduced reagent masses, minimizing impurities. This enables purification with lower-capacity methods, such as analytical HPLC, with a reduction of purification time and volume (that shortens downstream re-formulation). Still, the need for a bulky and expensive HPLC system undermines many of the advantages of microfluidics. This study demonstrates the feasibility of using radio-TLC for the purification of radiopharmaceuticals. This technique combines high-performance (high-resolution, high-speed separation) with the advantages of a compact and low-cost setup. A further advantage is that no downstream re-formulation step is needed. Production and purification of clinical scale batches of [18F]PBR-06 and [18F]Fallypride are demonstrated with high yield, purity, and specific activity. Automating this radio-TLC method could provide an attractive solution for the purification step in microscale radiochemistry systems.
Collapse
|
5
|
18F-Radiolabeled Translocator Protein (TSPO) PET Tracers: Recent Development of TSPO Radioligands and Their Application to PET Study. Pharmaceutics 2022; 14:pharmaceutics14112545. [PMID: 36432736 PMCID: PMC9697781 DOI: 10.3390/pharmaceutics14112545] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Translocator protein 18 kDa (TSPO) is a transmembrane protein in the mitochondrial membrane, which has been identified as a peripheral benzodiazepine receptor. TSPO is generally present at high concentrations in steroid-producing cells and plays an important role in steroid synthesis, apoptosis, and cell proliferation. In the central nervous system, TSPO expression is relatively modest under normal physiological circumstances. However, some pathological disorders can lead to changes in TSPO expression. Overexpression of TSPO is associated with several diseases, such as neurodegenerative diseases, neuroinflammation, brain injury, and cancers. TSPO has therefore become an effective biomarker of related diseases. Positron emission tomography (PET), a non-invasive molecular imaging technique used for the clinical diagnosis of numerous diseases, can detect diseases related to TSPO expression. Several radiolabeled TSPO ligands have been developed for PET. In this review, we describe recent advances in the development of TSPO ligands, and 18F-radiolabeled TSPO in particular, as PET tracers. This review covers pharmacokinetic studies, preclinical and clinical trials of 18F-labeled TSPO PET ligands, and the synthesis of TSPO ligands.
Collapse
|
6
|
Ni R, Müller Herde A, Haider A, Keller C, Louloudis G, Vaas M, Schibli R, Ametamey SM, Klohs J, Mu L. In vivo Imaging of Cannabinoid Type 2 Receptors: Functional and Structural Alterations in Mouse Model of Cerebral Ischemia by PET and MRI. Mol Imaging Biol 2022; 24:700-709. [PMID: 34642898 PMCID: PMC9581861 DOI: 10.1007/s11307-021-01655-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE Stroke is one of the most prevalent vascular diseases. Non-invasive molecular imaging methods have the potential to provide critical insights into the temporal dynamics and follow alterations of receptor expression and metabolism in ischemic stroke. The aim of this study was to assess the cannabinoid type 2 receptor (CB2R) levels in transient middle cerebral artery occlusion (tMCAO) mouse models at subacute stage using positron emission tomography (PET) with our novel tracer [18F]RoSMA-18-d6 and structural imaging by magnetic resonance imaging (MRI). PROCEDURES Our recently developed CB2R PET tracer [18F]RoSMA-18-d6 was used for imaging neuroinflammation at 24 h after reperfusion in tMCAO mice. The RNA expression levels of CB2R and other inflammatory markers were analyzed by quantitative real-time polymerase chain reaction using brain tissues from tMCAO (1 h occlusion) and sham-operated mice. [18F]fluorodeoxyglucose (FDG) was included for evaluation of the cerebral metabolic rate of glucose (CMRglc). In addition, diffusion-weighted imaging and T2-weighted imaging were performed for anatomical reference and delineating the lesion in tMCAO mice. RESULTS mRNA expressions of inflammatory markers TNF-α, Iba1, MMP9 and GFAP, CNR2 were increased to 1.3-2.5 fold at 24 h after reperfusion in the ipsilateral compared to contralateral hemisphere of tMCAO mice, while mRNA expression of the neuronal marker MAP-2 was markedly reduced to ca. 50 %. Reduced [18F]FDG uptake was observed in the ischemic striatum of tMCAO mouse brain at 24 h after reperfusion. Although higher activity of [18F]RoSMA-18-d6 in ex vivo biodistribution studies and higher standard uptake value ratio (SUVR) were detected in the ischemic ipsilateral compared to contralateral striatum in tMCAO mice, the in vivo specificity of [18F]RoSMA-18-d6 was confirmed only in the CB2R-rich spleen. CONCLUSIONS This study revealed an increased [18F]RoSMA-18-d6 measure of CB2R and a reduced [18F]FDG measure of CMRglc in the ischemic striatum of tMCAO mice at subacute stage. [18F]RoSMA-18-d6 might be a promising PET tracer for detecting CB2R alterations in animal models of neuroinflammation without neuronal loss.
Collapse
Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Adrienne Müller Herde
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Ahmed Haider
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Claudia Keller
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Georgios Louloudis
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Markus Vaas
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Roger Schibli
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Simon M Ametamey
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Linjing Mu
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI H427 Vladimir-Prelog-Weg 1-5/10, 8093, Zurich, Switzerland.
- Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland.
| |
Collapse
|
7
|
Microglia and Stem-Cell Mediated Neuroprotection after Neonatal Hypoxia-Ischemia. Stem Cell Rev Rep 2021; 18:474-522. [PMID: 34382141 PMCID: PMC8930888 DOI: 10.1007/s12015-021-10213-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 12/14/2022]
Abstract
Neonatal hypoxia-ischemia encephalopathy (HIE) refers to a brain injury in term infants that can lead to death or lifelong neurological deficits such as cerebral palsy (CP). The pathogenesis of this disease involves multiple cellular and molecular events, notably a neuroinflammatory response driven partly by microglia, the brain resident macrophages. Treatment options are currently very limited, but stem cell (SC) therapy holds promise, as beneficial outcomes are reported in animal studies and to a lesser degree in human trials. Among putative mechanisms of action, immunomodulation is considered a major contributor to SC associated benefits. The goal of this review is to examine whether microglia is a cellular target of SC-mediated immunomodulation and whether the recruitment of microglia is linked to brain repair. We will first provide an overview on microglial activation in the rodent model of neonatal HI, and highlight its sensitivity to developmental age. Two complementary questions are then addressed: (i) do immune-related treatments impact microglia and provide neuroprotection, (ii) does stem cell treatment modulates microglia? Finally, the immune-related findings in patients enrolled in SC based clinical trials are discussed. Our review points to an impact of SCs on the microglial phenotype, but heterogeneity in experimental designs and methodological limitations hamper our understanding of a potential contribution of microglia to SC associated benefits. Thorough analyses of the microglial phenotype are warranted to better address the relevance of the neuroimmune crosstalk in brain repair and improve or advance the development of SC protocols in humans.
Collapse
|
8
|
Song YS, Lee SH, Jung JH, Song IH, Park HS, Moon BS, Kim SE, Lee BC. TSPO Expression Modulatory Effect of Acetylcholinesterase Inhibitor in the Ischemic Stroke Rat Model. Cells 2021; 10:cells10061350. [PMID: 34072449 PMCID: PMC8227181 DOI: 10.3390/cells10061350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/21/2022] Open
Abstract
We performed in vivo PET imaging with 3-[18F]F-CP118,954 (1) for acetylcholinesterase (AChE) and [18F]fluoromethyl-PBR28-d2 (2) for translocator protein 18-kDa (TSPO) to investigate the inflammatory brain response after stroke. Imaging studies were performed in the middle cerebral artery occlusion (MCAO) Sprague-Dawley rat model for a period of three weeks. The percentage injected dose per tissue weight (%ID/g) of striatum of 1, and cortex of 2 were obtained, respectively. To trace the sequential inflammatory responses, AChE imaging of 1 was done on post-MCAO day 2, after giving cold PK-11195 for 1 day, and TSPO imaging of 2 was carried out on post-MCAO day 11, after giving donepezil for 10 days. AChE activity in the MCAO-lesioned side were significantly higher than that of the contralateral side on day one, and TSPO activity was highest on day 11. TSPO inhibitor, PK-11195 did not affect AChE activity on day two, while AChE inhibitor, donepezil significantly lowered TSPO binding on day 12. Our study demonstrates that AChE level is elevated in the early course of brain ischemia as a trigger for the inflammatory response, and TSPO level is elevated persistently throughout the post-ischemic injury in the brain. Also, the AChE inhibitor may be able to inhibit or delay neurotoxic inflammatory responses and serve as a beneficial treatment option.
Collapse
Affiliation(s)
- Yoo Sung Song
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
| | - Sang Hee Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea
| | - Jae Ho Jung
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
| | - In Ho Song
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
| | - Hyun Soo Park
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
| | - Byung Seok Moon
- Department of Nuclear Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul 07804, Korea;
| | - Sang Eun Kim
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea
- Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Korea
- Correspondence: (S.E.K.); (B.C.L.); Tel.: +82-31-787-7671 (S.E.K.); +82-31-787-2956 (B.C.L.)
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 13620, Korea; (Y.S.S.); (S.H.L.); (J.H.J.); (I.H.S.); (H.S.P.)
- Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Korea
- Correspondence: (S.E.K.); (B.C.L.); Tel.: +82-31-787-7671 (S.E.K.); +82-31-787-2956 (B.C.L.)
| |
Collapse
|
9
|
Welcome MO, Mastorakis NE. The taste of neuroinflammation: Molecular mechanisms linking taste sensing to neuroinflammatory responses. Pharmacol Res 2021; 167:105557. [PMID: 33737243 DOI: 10.1016/j.phrs.2021.105557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 03/10/2021] [Accepted: 03/10/2021] [Indexed: 02/07/2023]
Abstract
Evidence indicates a critical role of neuroinflammatory response as an underlying pathophysiological process in several central nervous system disorders, including neurodegenerative diseases. However, the molecular mechanisms that trigger neuroinflammatory processes are not fully known. The discovery of bitter taste receptors in regions other than the oral cavity substantially increased research interests on their functional roles in extra-oral tissues. It is now widely accepted that bitter taste receptors, for instance, in the respiratory, intestinal, reproductive and urinary tracts, are crucial not only for sensing poisonous substances, but also, act as immune sentinels, mobilizing defense mechanisms against pathogenic aggression. The relatively recent discovery of bitter taste receptors in the brain has intensified research investigation on the functional implication of cerebral bitter taste receptor expression. Very recent data suggest that responses of bitter taste receptors to neurotoxins and microbial molecules, under normal condition, are necessary to prevent neuroinflammatory reactions. Furthermore, emerging data have revealed that downregulation of key components of the taste receptor signaling cascade leads to increased oxidative stress and inflammasome signaling in neurons that ultimately culminate in neuroinflammation. Nevertheless, the mechanisms that link taste receptor mediated surveillance of the extracellular milieu to neuroinflammatory responses are not completely understood. This review integrates new data on the molecular mechanisms that link bitter taste receptor sensing to neuroinflammatory responses. The role of bitter taste receptor-mediated sensing of toxigenic substances in brain disorders is also discussed. The therapeutic significance of targeting these receptors for potential treatment of neurodegenerative diseases is also highlighted.
Collapse
Affiliation(s)
- Menizibeya O Welcome
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Nile University of Nigeria, Abuja, Nigeria.
| | | |
Collapse
|
10
|
Zhang L, Hu K, Shao T, Hou L, Zhang S, Ye W, Josephson L, Meyer JH, Zhang MR, Vasdev N, Wang J, Xu H, Wang L, Liang SH. Recent developments on PET radiotracers for TSPO and their applications in neuroimaging. Acta Pharm Sin B 2021; 11:373-393. [PMID: 33643818 PMCID: PMC7893127 DOI: 10.1016/j.apsb.2020.08.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is predominately localized to the outer mitochondrial membrane in steroidogenic cells. Brain TSPO expression is relatively low under physiological conditions, but is upregulated in response to glial cell activation. As the primary index of neuroinflammation, TSPO is implicated in the pathogenesis and progression of numerous neuropsychiatric disorders and neurodegenerative diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), major depressive disorder (MDD) and obsessive compulsive disorder (OCD). In this context, numerous TSPO-targeted positron emission tomography (PET) tracers have been developed. Among them, several radioligands have advanced to clinical research studies. In this review, we will overview the recent development of TSPO PET tracers, focusing on the radioligand design, radioisotope labeling, pharmacokinetics, and PET imaging evaluation. Additionally, we will consider current limitations, as well as translational potential for future application of TSPO radiopharmaceuticals. This review aims to not only present the challenges in current TSPO PET imaging, but to also provide a new perspective on TSPO targeted PET tracer discovery efforts. Addressing these challenges will facilitate the translation of TSPO in clinical studies of neuroinflammation associated with central nervous system diseases.
Collapse
Key Words
- AD, Alzheimer's disease
- ALS, amyotrophic lateral sclerosis
- AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid
- ANT, adenine nucleotide transporter
- Am, molar activities
- BBB, blood‒brain barrier
- BMSC, bone marrow stromal cells
- BP, binding potential
- BPND, non-displaceable binding potential
- BcTSPO, Bacillus cereus TSPO
- CBD, corticobasal degeneration
- CNS disorders
- CNS, central nervous system
- CRAC, cholesterol recognition amino acid consensus sequence
- DLB, Lewy body dementias
- EP, epilepsy
- FTD, frontotemporal dementia
- HAB, high-affinity binding
- HD, Huntington's disease
- HSE, herpes simplex encephalitis
- IMM, inner mitochondrial membrane
- KA, kainic acid
- LAB, low-affinity binding
- LPS, lipopolysaccharide
- MAB, mixed-affinity binding
- MAO-B, monoamine oxidase B
- MCI, mild cognitive impairment
- MDD, major depressive disorder
- MMSE, mini-mental state examination
- MRI, magnetic resonance imaging
- MS, multiple sclerosis
- MSA, multiple system atrophy
- Microglial activation
- NAA/Cr, N-acetylaspartate/creatine
- Neuroinflammation
- OCD, obsessive compulsive disorder
- OMM, outer mitochondrial membrane
- P2X7R, purinergic receptor P2X7
- PAP7, RIa-associated protein
- PBR, peripheral benzodiazepine receptor
- PCA, posterior cortical atrophy
- PD, Parkinson's disease
- PDD, PD dementia
- PET, positron emission tomography
- PKA, protein kinase A
- PRAX-1, PBR-associated protein 1
- PSP, progressive supranuclear palsy
- Positron emission tomography (PET)
- PpIX, protoporphyrin IX
- QA, quinolinic acid
- RCYs, radiochemical yields
- ROS, reactive oxygen species
- RRMS, relapsing remitting multiple sclerosis
- SA, specific activity
- SAH, subarachnoid hemorrhage
- SAR, structure–activity relationship
- SCIDY, spirocyclic iodonium ylide
- SNL, selective neuronal loss
- SNR, signal to noise ratio
- SUV, standard uptake volume
- SUVR, standard uptake volume ratio
- TBAH, tetrabutyl ammonium hydroxide
- TBI, traumatic brain injury
- TLE, temporal lobe epilepsy
- TSPO
- TSPO, translocator protein
- VDAC, voltage-dependent anion channel
- VT, distribution volume
- d.c. RCYs, decay-corrected radiochemical yields
- dMCAO, distal middle cerebral artery occlusion
- fP, plasma free fraction
- n.d.c. RCYs, non-decay-corrected radiochemical yields
- p.i., post-injection
Collapse
|
11
|
An update into the medicinal chemistry of translocator protein (TSPO) ligands. Eur J Med Chem 2020; 209:112924. [PMID: 33081988 DOI: 10.1016/j.ejmech.2020.112924] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 01/16/2023]
Abstract
The Translocator Protein 18 kDa (TSPO) has been discovered in 1977 as an alternative binding site for the benzodiazepine diazepam. It is an evolutionary well-conserved and tryptophan-rich 169-amino acids protein with five alpha helical transmembrane domains stretching the outer mitochondrial membrane, with the carboxyl-terminus in the cytosol and a short amino-terminus in the intermembrane space of mitochondrion. At this level, together with the voltage-dependent anion channel (VDAC) and the adenine nucleotide translocase (ANT), it forms the mitochondrial permeability transition pore (MPTP). TSPO expression is ubiquitary, with higher levels in steroid producing tissues; in the central nervous system, it is mainly expressed in glial cells and in neurons. TSPO is implicated in a variety of fundamental cellular processes including steroidogenesis, heme biosynthesis, mitochondrial respiration, mitochondrial membrane potential, cell proliferation and differentiation, cell life/death balance, oxidative stress. Altered TSPO expression has been found in some pathological conditions. In particular, high TSPO expression levels have been documented in cancer, neuroinflammation, and brain injury. Conversely, low TSPO expression levels have been evidenced in anxiety disorders. Therefore, TSPO is not only an interesting drug target for therapeutic purpose (anticonvulsant, anxiolytic, etc.), but also a valid diagnostic marker of related-diseases detectable by fluorescent or radiolabeled ligands. The aim of this report is to present an update of previous reviews dealing with the medicinal chemistry of TSPO and to highlight the most outstanding advances in the development of TSPO ligands as potential therapeutic or diagnostic tools, especially referring to the last five years.
Collapse
|
12
|
Singhal T, Cicero S, Pan H, Carter K, Dubey S, Chu R, Glanz B, Hurwitz S, Tauhid S, Park MA, Kijewski M, Stern E, Bakshi R, Silbersweig D, Weiner HL. Regional microglial activation in the substantia nigra is linked with fatigue in MS. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2020; 7:7/5/e854. [PMID: 32769103 PMCID: PMC7643614 DOI: 10.1212/nxi.0000000000000854] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/18/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The goal of our study is to assess the role of microglial activation in MS-associated fatigue (MSAF) using [F-18]PBR06-PET. METHODS Fatigue severity was measured using the Modified Fatigue Impact Scale (MFIS) in 12 subjects with MS (7 relapsing-remitting and 5 secondary progressive) and 10 healthy control participants who underwent [F-18]PBR06-PET. The MFIS provides a total fatigue score as well as physical, cognitive, and psychosocial fatigue subscale scores. Standardized Uptake Value (SUV) 60-90 minute frame PET maps were coregistered to 3T MRI. Voxel-by-voxel analysis using Statistical Parametric Mapping and atlas-based regional analyses were performed. SUV ratios (SUVRs) were global brain normalized. RESULTS Peak voxel-based level of significance for correlation between total fatigue score and PET uptake was localized to the right substantia nigra (T-score 4.67, p = 0.001). Similarly, SUVRs derived from atlas-based segmentation of the substantia nigra showed significant correlation with MFIS (r = 0.76, p = 0.004). On multiple regression, the right substantia nigra was an independent predictor of total MFIS (p = 0.02) and cognitive MFIS subscale values (p = 0.007), after adjustment for age, disability, and depression. Several additional areas of significant correlations with fatigue scores were identified, including the right parahippocampal gyrus, right precuneus, and juxtacortical white matter (all p < 0.05). There was no correlation between fatigue scores and brain atrophy and lesion load in patients with MS. CONCLUSION Substantia nigra microglial activation is linked to fatigue in MS. Microglial activation across key brain regions may represent a unifying mechanism for MSAF, and further evaluation of neuroimmunologic basis of MSAF is warranted.
Collapse
Affiliation(s)
- Tarun Singhal
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
| | - Steven Cicero
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Hong Pan
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Kelsey Carter
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shipra Dubey
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Renxin Chu
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Bonnie Glanz
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shelley Hurwitz
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shahamat Tauhid
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Mi-Ae Park
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Marie Kijewski
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Emily Stern
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Rohit Bakshi
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - David Silbersweig
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Howard L Weiner
- From the Partners MS Center (T.S., S.C., K.C., B.G., R.B., H.L.W.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; PET Imaging Program in Neurologic Diseases (T.S., S.C., K.C.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Functional Neuroimaging Laboratory (H.P., R.B., D.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of Nuclear Medicine and Molecular Imaging (S.D., M.-A.P., M.K.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Laboratory for Neuroimaging Research (R.C., S.T.), Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Department of Medicine (S.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Ceretype Neuromedicine (E.S.)Department of Radiology (R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
13
|
Neuroinflammation in CNS diseases: Molecular mechanisms and the therapeutic potential of plant derived bioactive molecules. PHARMANUTRITION 2020. [DOI: 10.1016/j.phanu.2020.100176] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
14
|
Assessing the Effects of Cytoprotectants on Selective Neuronal Loss, Sensorimotor Deficit and Microglial Activation after Temporary Middle Cerebral Occlusion. Brain Sci 2019; 9:brainsci9100287. [PMID: 31652564 PMCID: PMC6827002 DOI: 10.3390/brainsci9100287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 01/21/2023] Open
Abstract
Although early reperfusion after stroke salvages the still-viable ischemic tissue, peri-infarct selective neuronal loss (SNL) can cause sensorimotor deficits (SMD). We designed a longitudinal protocol to assess the effects of cytoprotectants on SMD, microglial activation (MA) and SNL, and specifically tested whether the KCa3.1-blocker TRAM-34 would prevent SNL. Spontaneously hypertensive rats underwent 15 min middle-cerebral artery occlusion and were randomized into control or treatment group, which received TRAM-34 intraperitoneally for 4 weeks starting 12 h after reperfusion. SMD was assessed longitudinally using the sticky-label test. MA was quantified at day 14 using in vivo [11C]-PK111195 positron emission tomography (PET), and again across the same regions-of-interest template by immunofluorescence together with SNL at day 28. SMD recovered significantly faster in the treated group (p = 0.004). On PET, MA was present in 5/6 rats in each group, with no significant between-group difference. On immunofluorescence, both SNL and MA were present in 5/6 control rats and 4/6 TRAM-34 rats, with a non-significantly lower degree of MA but a significantly (p = 0.009) lower degree of SNL in the treated group. These findings document the utility of our longitudinal protocol and suggest that TRAM-34 reduces SNL and hastens behavioural recovery without marked MA blocking at the assessed time-points.
Collapse
|
15
|
Singhal T, O'Connor K, Dubey S, Pan H, Chu R, Hurwitz S, Cicero S, Tauhid S, Silbersweig D, Stern E, Kijewski M, DiCarli M, Weiner HL, Bakshi R. Gray matter microglial activation in relapsing vs progressive MS: A [F-18]PBR06-PET study. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2019; 6:e587. [PMID: 31355321 PMCID: PMC6624145 DOI: 10.1212/nxi.0000000000000587] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/15/2019] [Indexed: 11/15/2022]
Abstract
Objective To determine the value of [F-18]PBR06-PET for assessment of microglial activation in the cerebral gray matter in patients with MS. Methods Twelve patients with MS (7 relapsing-remitting and 5 secondary progressive [SP]) and 5 healthy controls (HCs) had standardized uptake value (SUV) PET maps coregistered to 3T MRI and segmented into cortical and subcortical gray matter regions. SUV ratios (SUVRs) were global brain normalized. Voxel-by-voxel analysis was performed using statistical parametric mapping (SPM). Normalized brain parenchymal volumes (BPVs) were determined from MRI using SIENAX. Results Cortical SUVRs were higher in the hippocampus, amygdala, midcingulate, posterior cingulate, and rolandic operculum and lower in the medial-superior frontal gyrus and cuneus in the MS vs HC group (all p < 0.05). Subcortical gray matter SUVR was higher in SPMS vs RRMS (+10.8%, p = 0.002) and HC (+11.3%, p = 0.055) groups. In the MS group, subcortical gray matter SUVR correlated with the Expanded Disability Status Scale (EDSS) score (r = 0.75, p = 0.005) and timed 25-foot walk (T25FW) (r = 0.70, p = 0.01). Thalamic SUVRs increased with increasing EDSS scores (r = 0.83, p = 0.0008) and T25FW (r = 0.65, p = 0.02) and with decreasing BPV (r = -0.63, p = 0.03). Putaminal SUVRs increased with increasing EDSS scores (0.71, p = 0.009) and with decreasing BPV (r = -0.67, p = 0.01). On SPM analysis, peak correlations of thalamic voxels with BPV were seen in the pulvinar and with the EDSS score and T25FW in the dorsomedial thalamic nuclei. Conclusions This study suggests that [F-18]PBR06-PET detects widespread abnormal microglial activation in the cerebral gray matter in MS. Increased translocator protein binding in subcortical gray matter regions is associated with brain atrophy and may link to progressive MS.
Collapse
Affiliation(s)
- Tarun Singhal
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Kelsey O'Connor
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shipra Dubey
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Hong Pan
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Renxin Chu
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shelley Hurwitz
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Steven Cicero
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Shahamat Tauhid
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - David Silbersweig
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Emily Stern
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Marie Kijewski
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Marcelo DiCarli
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Howard L Weiner
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Rohit Bakshi
- Partners MS Center (T.S., K.O.C., R.C., S.C., S.T., H.L.W., R.B.), Laboratory for Neuroimaging Research, Ann Romney Center for Neurological Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School; Division of Nuclear Medicine and Molecular Imaging (S.D., M.K., M.D.), Department of Radiology, Brigham and Women's Hospital, Harvard Medical School; Functional Neuroimaging Laboratory (H.P., D.S., E.S.), Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School; Department of Medicine (S.H.) and Department of Radiology (E.S., R.B.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
16
|
Huang S, Li C, Guo J, Zhang L, Wu S, Wang H, Liang S. Monitoring the Progression of Chronic Liver Damage in Rats Using [18F]PBR06. Mol Imaging Biol 2018; 21:669-675. [DOI: 10.1007/s11307-018-1282-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Hierro-Bujalance C, Bacskai BJ, Garcia-Alloza M. In Vivo Imaging of Microglia With Multiphoton Microscopy. Front Aging Neurosci 2018; 10:218. [PMID: 30072888 PMCID: PMC6060250 DOI: 10.3389/fnagi.2018.00218] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/26/2018] [Indexed: 01/04/2023] Open
Abstract
Neuroimaging has become an unparalleled tool to understand the central nervous system (CNS) anatomy, physiology and neurological diseases. While an altered immune function and microglia hyperactivation are common neuropathological features for many CNS disorders and neurodegenerative diseases, direct assessment of the role of microglial cells remains a challenging task. Non-invasive neuroimaging techniques, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single positron emission computed tomography (SPECT) are widely used for human clinical applications, and a variety of ligands are available to detect neuroinflammation. In animal models, intravital imaging has been largely used, and minimally invasive multiphoton microcopy (MPM) provides high resolution detection of single microglia cells, longitudinally, in living brain. In this study, we review in vivo real-time MPM approaches to assess microglia in preclinical studies, including individual cell responses in surveillance, support, protection and restoration of brain tissue integrity, synapse formation, homeostasis, as well as in different pathological situations. We focus on in vivo studies that assess the role of microglia in mouse models of Alzheimer’s disease (AD), analyzing microglial motility and recruitment, as well as the role of microglia in anti-amyloid-β treatment, as a key therapeutic approach to treat AD. Altogether, MPM provides a high contrast and high spatial resolution approach to follow microglia chronically in vivo in complex models, supporting MPM as a powerful tool for deep intravital tissue imaging.
Collapse
Affiliation(s)
- Carmen Hierro-Bujalance
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| |
Collapse
|
19
|
Chaney A, Cropper HC, Johnson EM, Lechtenberg KJ, Peterson TC, Stevens MY, Buckwalter MS, James ML. 11C-DPA-713 Versus 18F-GE-180: A Preclinical Comparison of Translocator Protein 18 kDa PET Tracers to Visualize Acute and Chronic Neuroinflammation in a Mouse Model of Ischemic Stroke. J Nucl Med 2018; 60:122-128. [PMID: 29976695 PMCID: PMC6354224 DOI: 10.2967/jnumed.118.209155] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/23/2018] [Indexed: 12/12/2022] Open
Abstract
Neuroinflammation plays a key role in neuronal injury after ischemic stroke. PET imaging of translocator protein 18 kDa (TSPO) permits longitudinal, noninvasive visualization of neuroinflammation in both preclinical and clinical settings. Many TSPO tracers have been developed, however, it is unclear which tracer is the most sensitive and accurate for monitoring the in vivo spatiotemporal dynamics of neuroinflammation across applications. Hence, there is a need for head-to-head comparisons of promising TSPO PET tracers across different disease states. Accordingly, the aim of this study was to directly compare 2 promising second-generation TSPO tracers, 11C-DPA-713 and 18F-GE-180, for the first time at acute and chronic time points after ischemic stroke. Methods: After distal middle cerebral artery occlusion or sham surgery, mice underwent consecutive PET/CT imaging with 11C-DPA-713 and 18F-GE-180 at 2, 6, and 28 d after stroke. T2-weighted MR images were acquired to enable delineation of ipsilateral (infarct) and contralateral brain regions of interest (ROIs). PET/CT images were analyzed by calculating percentage injected dose per gram in MR-guided ROIs. SUV ratios were determined using the contralateral thalamus (SUVTh) as a pseudoreference region. Ex vivo autoradiography and immunohistochemistry were performed to verify in vivo findings. Results: Significantly increased tracer uptake was observed in the ipsilateral compared with contralateral ROI (SUVTh, 50-60 min summed data) at acute and chronic time points using 11C-DPA-713 and 18F-GE-180. Ex vivo autoradiography confirmed in vivo findings demonstrating increased TSPO tracer uptake in infarcted versus contralateral brain tissue. Importantly, a significant correlation was identified between microglial/macrophage activation (cluster of differentiation 68 immunostaining) and 11C-DPA-713- PET signal, which was not evident with 18F-GE-180. No significant correlations were observed between TSPO PET and activated astrocytes (glial fibrillary acidic protein immunostaining). Conclusion: 11C-DPA-713 and 18F-GE-180 PET enable detection of neuroinflammation at acute and chronic time points after cerebral ischemia in mice. 11C-DPA-713 PET reflects the extent of microglial activation in infarcted distal middle cerebral artery occlusion mouse brain tissue more accurately than 18F-GE-180 and appears to be slightly more sensitive. These results highlight the potential of 11C-DPA-713 for tracking microglial activation in vivo after stroke and warrant further investigation in both preclinical and clinical settings.
Collapse
Affiliation(s)
- Aisling Chaney
- Department of Radiology, Stanford University, Stanford California
| | - Haley C Cropper
- Department of Radiology, Stanford University, Stanford California
| | - Emily M Johnson
- Department of Radiology, Stanford University, Stanford California
| | - Kendra J Lechtenberg
- Department of Neurology and Neurological Sciences, Stanford University, Stanford California; and
| | - Todd C Peterson
- Department of Neurology and Neurological Sciences, Stanford University, Stanford California; and
| | - Marc Y Stevens
- Department of Radiology, Stanford University, Stanford California
| | - Marion S Buckwalter
- Department of Neurology and Neurological Sciences, Stanford University, Stanford California; and.,Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | - Michelle L James
- Department of Radiology, Stanford University, Stanford California .,Department of Neurology and Neurological Sciences, Stanford University, Stanford California; and
| |
Collapse
|
20
|
Selvaraj S, Bloomfield PS, Cao B, Veronese M, Turkheimer F, Howes OD. Brain TSPO imaging and gray matter volume in schizophrenia patients and in people at ultra high risk of psychosis: An [ 11C]PBR28 study. Schizophr Res 2018; 195:206-214. [PMID: 28893493 PMCID: PMC6027955 DOI: 10.1016/j.schres.2017.08.063] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/12/2022]
Abstract
Patients with schizophrenia show whole brain and cortical gray matter (GM) volume reductions which are progressive early in their illness. Microglia, the resident immune cells in the CNS, phagocytose neurons and synapses. Some post mortem and in vivo studies in schizophrenia show evidence for elevated microglial activation compared to matched controls. However, it is currently unclear how these results relate to changes in cortical structure. METHODS Fourteen patients with schizophrenia and 14 ultra high risk for psychosis (UHR) subjects alongside two groups of age and genotype matched healthy controls received [11C]PBR28 PET scans to index TSPO expression, a marker of microglial activation and a 3T MRI scan. We investigated the relationship between the volume changes of cortical regions and microglial activation in cortical GM (as indexed by [11C]PBR28 distribution volume ratio (DVR). RESULTS The total cortical GM volume was significantly lower in SCZ than the controls [mean (SD)/cm3: SCZ=448.83 (39.2) and controls=499.6 (59.2) (p=0.02) but not in UHR (mean (SD)=503.06 (57.9) and controls=524.46 (45.3) p=0.3). Regression model fitted the total cortical GM DVR values with the cortical regional volumes in SCZ (r=0.81; p<0.001) and in UHR (r=0.63; p=0.02). We found a significant negative correlation between the TSPO signal and total cortical GM volume in SCZ with the highest absolute correlation coefficient in the right superior-parietal cortex (r=-0.72; p=0.006). CONCLUSIONS These findings suggest that microglial activity is related to the altered cortical volume seen in schizophrenia. Longitudinal investigations are required to determine whether microglial activation leads to cortical gray matter loss.
Collapse
Affiliation(s)
- Sudhakar Selvaraj
- Department of Psychiatry and Behavioural Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; Psychiatric Imaging Group, MRC Clinical Sciences Centre, Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital, London, W12 0NN, UK.
| | - Peter S Bloomfield
- Psychiatric Imaging Group, MRC Clinical Sciences Centre, Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital, London, W12 0NN, UK
| | - Bo Cao
- Department of Psychiatry and Behavioural Sciences, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Mattia Veronese
- Centre for Neuroimaging Sciences, IoPPN, King's College London, Box PO89, De Crespigny Park, London SE5 8AF, UK
| | - Federico Turkheimer
- Centre for Neuroimaging Sciences, IoPPN, King's College London, Box PO89, De Crespigny Park, London SE5 8AF, UK
| | - Oliver D Howes
- Psychiatric Imaging Group, MRC Clinical Sciences Centre, Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital, London, W12 0NN, UK; Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK
| |
Collapse
|
21
|
Nguyen DL, Wimberley C, Truillet C, Jego B, Caillé F, Pottier G, Boisgard R, Buvat I, Bouilleret V. Longitudinal positron emission tomography imaging of glial cell activation in a mouse model of mesial temporal lobe epilepsy: Toward identification of optimal treatment windows. Epilepsia 2018; 59:1234-1244. [PMID: 29672844 DOI: 10.1111/epi.14083] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2018] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Mesiotemporal lobe epilepsy is the most common type of drug-resistant partial epilepsy, with a specific history that often begins with status epilepticus due to various neurological insults followed by a silent period. During this period, before the first seizure occurs, a specific lesion develops, described as unilateral hippocampal sclerosis (HS). It is still challenging to determine which drugs, administered at which time point, will be most effective during the formation of this epileptic process. Neuroinflammation plays an important role in pathophysiological mechanisms in epilepsy, and therefore brain inflammation biomarkers such as translocator protein 18 kDa (TSPO) can be potent epilepsy biomarkers. TSPO is associated with reactive astrocytes and microglia. A unilateral intrahippocampal kainate injection mouse model can reproduce the defining features of human temporal lobe epilepsy with unilateral HS and the pattern of chronic pharmacoresistant temporal seizures. We hypothesized that longitudinal imaging using TSPO positron emission tomography (PET) with 18 F-DPA-714 could identify optimal treatment windows in a mouse model during the formation of HS. METHODS The model was induced into the right dorsal hippocampus of male C57/Bl6 mice. Micro-PET/computed tomographic scanning was performed before model induction and along the development of the HS at 7 days, 14 days, 1 month, and 6 months. In vitro autoradiography and immunohistofluorescence were performed on additional mice at each time point. RESULTS TSPO PET uptake reached peak at 7 days and mostly related to microglial activation, whereas after 14 days, reactive astrocytes were shown to be the main cells expressing TSPO, reflected by a continuing increased PET uptake. SIGNIFICANCE TSPO-targeted PET is a highly potent longitudinal biomarker of epilepsy and could be of interest to determine the therapeutic windows in epilepsy and to monitor response to treatment.
Collapse
Affiliation(s)
- Duc-Loc Nguyen
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Catriona Wimberley
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Charles Truillet
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Benoit Jego
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Fabien Caillé
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Géraldine Pottier
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Raphaël Boisgard
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Irène Buvat
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France
| | - Viviane Bouilleret
- In Vivo Molecular Imaging Laboratory (IMIV), French National Institute of Health and Medical Research (INSERM), French Alternative Energies and Atomic Energy Commission (CEA), French National Center for Scientific Research (CNRS), Paris Saclay University, Frédéric Joliot Hospital service, Orsay, France.,Neurophysiology and Epilepsy Unit, Bicêtre Hospital, Public Hospitals of Paris (AP-HP), France
| |
Collapse
|
22
|
Bok S, Kim YE, Woo Y, Kim S, Kang SJ, Lee Y, Park SK, Weissman IL, Ahn GO. Hypoxia-inducible factor-1α regulates microglial functions affecting neuronal survival in the acute phase of ischemic stroke in mice. Oncotarget 2017; 8:111508-111521. [PMID: 29340071 PMCID: PMC5762339 DOI: 10.18632/oncotarget.22851] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/16/2017] [Indexed: 01/12/2023] Open
Abstract
Cells universally adapt to ischemic conditions by turning on a transcription factor hypoxia-inducible factor (HIF), in which its role is known to differ widely across many different types of cells. Given that microglia have been reported as an essential mediator of neuroinflammation in many brain diseases, we examined the role of HIF in microglia in the progression of an acute phase of ischemic stroke by challenging our novel strains of myeloid-specific Hif-1α or Hif-2α knockout (KO) mice created by Cre-loxP system via middle cerebral artery occlusion (MCAO). We observed that Hif-1α but not Hif-2α KO mice exhibited an improved recovery compared to wild-type (WT) mice determined by behavioral tests. Immunostaining analyses revealed that there were increased numbers of both mature and immature neurons while microglia and apoptotic cells were significantly decreased in the dentate gyrus of Hif-1α KO mice following MCAO. By isolating microglia with fluorescence-activated cell sorter, we found that HIF-1α-deficient microglia were impaired in phagocytosis, reactive oxygen species (ROS) production, and tumor necrosis factor-α (TNF-α) secretion. We further observed a significant decrease in the expression of Cd36 and milk fat globule-epidermal growth factor 8 (Mfg-e8) genes, both of which contain hypoxia-responsive element (HRE). Knocking down either of these genes in BV2 microglial cells was sufficient to abrogate HIF-mediated increase in phagocytosis, production of intracellular ROS, or TNF-α secretion. Our results therefore suggest that HIF-1α in microglia is a novel therapeutic target to protect neuronal survival following an acute phase of ischemic stroke.
Collapse
Affiliation(s)
- Seoyeon Bok
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea.,Current/Present address: Department of Radiation Oncology, Yonsei University College of Medicine, Yonsei University Health System, Seoul 03722, Korea
| | - Young-Eun Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Youngsik Woo
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Soeun Kim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Suk-Jo Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Yoontae Lee
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Sang Ki Park
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Irving L Weissman
- Stem Cell Institute and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - G-One Ahn
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| |
Collapse
|
23
|
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.
Collapse
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.
| |
Collapse
|
24
|
Sridharan S, Lepelletier FX, Trigg W, Banister S, Reekie T, Kassiou M, Gerhard A, Hinz R, Boutin H. Comparative Evaluation of Three TSPO PET Radiotracers in a LPS-Induced Model of Mild Neuroinflammation in Rats. Mol Imaging Biol 2017; 19:77-89. [PMID: 27481358 PMCID: PMC5209405 DOI: 10.1007/s11307-016-0984-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Purpose Over the past 20 years, neuroinflammation (NI) has increasingly been recognised as having an important role in many neurodegenerative diseases, including Alzheimer’s disease. As such, being able to image NI non-invasively in patients is critical to monitor pathological processes and potential therapies targeting neuroinflammation. The translocator protein (TSPO) has proven a reliable NI biomarker for positron emission tomography (PET) imaging. However, if TSPO imaging in acute conditions such as stroke provides strong and reliable signals, TSPO imaging in neurodegenerative diseases has proven more challenging. Here, we report results comparing the recently developed TSPO tracers [18F]GE-180 and [18F]DPA-714 with (R)-[11C]PK11195 in a rodent model of subtle focal inflammation. Procedures Adult male Wistar rats were stereotactically injected with 1 μg lipopolysaccharide in the right striatum. Three days later, animals underwent a 60-min PET scan with (R)-[11C]PK11195 and [18F]GE-180 (n = 6) or [18F]DPA-714 (n = 6). Ten animals were scanned with either [18F]GE-180 (n = 5) or [18F]DPA-714 (n = 5) only. Kinetic analysis of PET data was performed using the simplified reference tissue model (SRTM) with a contralateral reference region or a novel data-driven input to estimate binding potential BPND. Autoradiography and immunohistochemistry were performed to confirm in vivo results. Results At 40–60 min post-injection, [18F]GE-180 dual-scanned animals showed a significantly increased core/contralateral uptake ratio vs. the same animals scanned with (R)-[11C]PK11195 (3.41 ± 1.09 vs. 2.43 ± 0.39, p = 0.03); [18]DPA-714 did not (2.80 ± 0.69 vs. 2.26 ± 0.41). Kinetic modelling with a contralateral reference region identified significantly higher binding potential (BPND) in the core of the LPS injection site with [18F]GE-180 but not with [18F]DPA-714 vs. (R)-[11C]PK11195. A cerebellar reference region and novel data-driven input to the SRTM were unable to distinguish differences in tracer BPND. Conclusions Second-generation TSPO-PET tracers are able to accurately detect mild-level NI. In this model, [18F]GE-180 shows a higher core/contralateral ratio and BPND when compared to (R)-[11C]PK11195, while [18F]DPA-714 did not. Electronic supplementary material The online version of this article (doi:10.1007/s11307-016-0984-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sujata Sridharan
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, M20 3LJ, UK
| | | | - William Trigg
- GE Healthcare, The Grove Centre, Amersham, Buckinghamshire, UK
| | - Samuel Banister
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
| | - Tristan Reekie
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
| | - Michael Kassiou
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia.,Faculty of Health Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Alexander Gerhard
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, M20 3LJ, UK
| | - Rainer Hinz
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, M20 3LJ, UK
| | - Hervé Boutin
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, M20 3LJ, UK.
| |
Collapse
|
25
|
Effect of Cigarette Smoking on a Marker for Neuroinflammation: A [ 11C]DAA1106 Positron Emission Tomography Study. Neuropsychopharmacology 2017; 42:1630-1639. [PMID: 28262740 PMCID: PMC5518907 DOI: 10.1038/npp.2017.48] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/01/2017] [Accepted: 02/23/2017] [Indexed: 01/21/2023]
Abstract
In the brain, microglia continuously scan the surrounding extracellular space in order to respond to damage or infection by becoming activated and participating in neuroinflammation. When activated, microglia increase the expression of translocator protein (TSPO) 18 kDa, thereby making the TSPO expression a marker for neuroinflammation. We used the radiotracer [11C]DAA1106 (a ligand for TSPO) and positron emission tomography (PET) to determine the effect of smoking on availability of this marker for neuroinflammation. Forty-five participants (30 smokers and 15 non-smokers) completed the study and had usable data. Participants underwent a dynamic PET scanning session with bolus injection of [11C]DAA1106 (with smokers in the satiated state) and blood draws during PET scanning to determine TSPO affinity genotype and plasma nicotine levels. Whole-brain standardized uptake values (SUVs) were determined, and analysis of variance was performed, with group (smoker vs non-smoker) and genotype as factors, thereby controlling for genotype. Smokers and non-smokers differed in whole-brain SUVs (P=0.006) owing to smokers having 16.8% lower values than non-smokers. The groups did not differ in injected radiotracer dose or body weight, which were used to calculate SUV. An inverse association was found between whole-brain SUV and reported cigarettes per day (P<0.05), but no significant relationship was found for plasma nicotine. Thus, smokers have less [11C]DAA1106 binding globally than non-smokers, indicating less microglial activation. Study findings are consistent with much prior research demonstrating that smokers have impaired inflammatory functioning compared with non-smokers and that constituents of tobacco smoke other than nicotine affect inflammatory processes.
Collapse
|
26
|
James ML, Belichenko NP, Shuhendler AJ, Hoehne A, Andrews LE, Condon C, Nguyen TVV, Reiser V, Jones P, Trigg W, Rao J, Gambhir SS, Longo FM. [ 18F]GE-180 PET Detects Reduced Microglia Activation After LM11A-31 Therapy in a Mouse Model of Alzheimer's Disease. Theranostics 2017; 7:1422-1436. [PMID: 28529627 PMCID: PMC5436503 DOI: 10.7150/thno.17666] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/08/2017] [Indexed: 12/22/2022] Open
Abstract
Microglial activation is a key pathological feature of Alzheimer's disease (AD). PET imaging of translocator protein 18 kDa (TSPO) is a strategy to detect microglial activation in vivo. Here we assessed flutriciclamide ([18F]GE-180), a new second-generation TSPO-PET radiotracer, for its ability to monitor response to LM11A-31, a novel AD therapeutic in clinical trials. AD mice displaying pathology were treated orally with LM11A-31 for 3 months. Subsequent [18F]GE-180-PET imaging revealed significantly lower signal in cortex and hippocampus of LM11A-31-treated AD mice compared to those treated with vehicle, corresponding with decreased levels of TSPO immunostaining and microglial Iba1 immunostaining. In addition to detecting decreased microglial activation following LM11A-31 treatment, [18F]GE-180 identified activated microglia in AD mice with greater sensitivity than another second-generation TSPO radiotracer, [18F]PBR06. Together, these data demonstrate the promise of [18F]GE-180 as a potentially sensitive tool for tracking neuroinflammation in AD mice and for monitoring therapeutic modulation of microglial activation.
Collapse
Affiliation(s)
- Michelle L. James
- Department of Radiology, Stanford University, Stanford, 94305, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, 94305, USA
| | - Nadia P. Belichenko
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, 94305, USA
| | | | - Aileen Hoehne
- Department of Radiology, Stanford University, Stanford, 94305, USA
| | | | - Christina Condon
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, 94305, USA
| | - Thuy-Vi V. Nguyen
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, 94305, USA
| | | | - Paul Jones
- GE Healthcare, Amersham HP7 9LL, United Kingdom
| | | | - Jianghong Rao
- Department of Radiology, Stanford University, Stanford, 94305, USA
| | | | - Frank M. Longo
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, 94305, USA
| |
Collapse
|
27
|
Abstract
PURPOSE OF REVIEW This article provides an overview of the recent literature regarding the application of in-vivo brain imaging techniques to animal models of ischemic stroke. RECENT FINDINGS Major breakthroughs concerned the effects of sensory stimulation on neuronal function, local hemodynamics, and tissue outcome in the hyperacute phase of stroke; the novel application to stroke of hybrid scanners allowing simultaneous PET and magnetic resonance; the refinements of magnetic resonance-based oxygen imaging, allowing to map the ischemic penumbra in a completely noninvasive way; the implementation of new PET ligands to selectively map poststroke neuronal death and neuroinflammation; and the use of novel mesoscale imaging techniques to demonstrate the major role of interhemispheric connectivity in poststroke plasticity and functional recovery. SUMMARY The array of techniques to map in vivo the key pathophysiological brain processes involved in stroke is currently enlarging at an amazing pace. This is paralleled by ever-increasing sophistication in postprocessing tools. The combination of techniques allowing simultaneous access to several variables is particularly powerful as it affords unprecedented insights into the intimate processes underlying the tissue and neuronal changes that follow a stroke. These major leaps forward will hopefully lead to therapeutic breakthroughs aiming at improving functional outcome after stroke.
Collapse
|
28
|
Moraga A, Gómez-Vallejo V, Cuartero MI, Szczupak B, San Sebastián E, Markuerkiaga I, Pradillo JM, Higuchi M, Llop J, Moro MÁ, Martín A, Lizasoain I. Imaging the role of toll-like receptor 4 on cell proliferation and inflammation after cerebral ischemia by positron emission tomography. J Cereb Blood Flow Metab 2016; 36:702-8. [PMID: 26787106 PMCID: PMC4821030 DOI: 10.1177/0271678x15627657] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/21/2015] [Indexed: 01/31/2023]
Abstract
The influence of toll-like receptor 4 on neurogenesis and inflammation has been scarcely explored so far by using neuroimaging techniques. For this purpose, we performed magnetic resonance imaging and positron emission tomography with 3'-deoxy-3'-[(18)F]fluorothymidine and [(11)C]PK11195 at 2, 7, and 14 days following cerebral ischemia in TLR4(+/+)and TLR4(-/-)mice. MRI showed similar infarction volumes in both groups. Despite this, positron emission tomography with 3'-deoxy-3'-[(18)F]fluorothymidine and [(11)C]PK11195 evidenced an increase of neurogenesis and a decrease of inflammation in TLR4(-/-)mice after ischemia. These results evidence the versatility of neuroimaging techniques to monitor the role of toll-like receptor 4 after cerebral ischemia.
Collapse
Affiliation(s)
- Ana Moraga
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain
| | - Vanessa Gómez-Vallejo
- Radiochemistry, Molecular Imaging Unit, CIC, biomaGUNE, San Sebastian, Guipuzcoa, Spain
| | - María Isabel Cuartero
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain
| | - Boguslaw Szczupak
- Molecular Imaging Unit, CIC biomaGUNE, San Sebastian, Guipuzcoa. Spain
| | | | | | - Jesús M Pradillo
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain
| | - Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Jordi Llop
- Radiochemistry, Molecular Imaging Unit, CIC, biomaGUNE, San Sebastian, Guipuzcoa, Spain
| | - María Ángeles Moro
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain
| | - Abraham Martín
- Molecular Imaging Unit, CIC biomaGUNE, San Sebastian, Guipuzcoa. Spain
| | - Ignacio Lizasoain
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid and Instituto de Investigación Hospital 12 de Octubre (i + 12), Madrid, Spain
| |
Collapse
|
29
|
In Vivo Detection of Age- and Disease-Related Increases in Neuroinflammation by 18F-GE180 TSPO MicroPET Imaging in Wild-Type and Alzheimer's Transgenic Mice. J Neurosci 2016; 35:15716-30. [PMID: 26609163 DOI: 10.1523/jneurosci.0996-15.2015] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Alzheimer's disease (AD) is the most common cause of dementia. Neuroinflammation appears to play an important role in AD pathogenesis. Ligands of the 18 kDa translocator protein (TSPO), a marker for activated microglia, have been used as positron emission tomography (PET) tracers to reflect neuroinflammation in humans and mouse models. Here, we used the novel TSPO-targeted PET tracer (18)F-GE180 (flutriciclamide) to investigate differences in neuroinflammation between young and old WT and APP/PS1dE9 transgenic (Tg) mice. In vivo PET scans revealed an overt age-dependent elevation in whole-brain uptake of (18)F-GE180 in both WT and Tg mice, and a significant increase in whole-brain uptake of (18)F-GE180 (peak-uptake and retention) in old Tg mice compared with young Tg mice and all WT mice. Similarly, the (18)F-GE180 binding potential in hippocampus was highest to lowest in old Tg > old WT > young Tg > young WT mice using MRI coregistration. Ex vivo PET and autoradiography analysis further confirmed our in vivo PET results: enhanced uptake and specific binding (SUV75%) of (18)F-GE180 in hippocampus and cortex was highest in old Tg mice followed by old WT, young Tg, and finally young WT mice. (18)F-GE180 specificity was confirmed by an in vivo cold tracer competition study. We also examined (18)F-GE180 metabolites in 4-month-old WT mice and found that, although total radioactivity declined over 2 h, of the remaining radioactivity, ∼90% was due to parent (18)F-GE180. In conclusion, (18)F-GE180 PET scans may be useful for longitudinal monitoring of neuroinflammation during AD progression and treatment. SIGNIFICANCE STATEMENT Microglial activation, a player in Alzheimer's disease (AD) pathogenesis, is thought to reflect neuroinflammation. Using in vivo microPET imaging with a novel TSPO radioligand, (18)F-GE180, we detected significantly enhanced neuroinflammation during normal aging in WT mice and in response to AD-associated pathology in APP/PS1dE9 Tg mice, an AD mouse model. Increased uptake and specific binding of (18)F-GE180 in whole brain and hippocampus were confirmed by ex vivo PET and autoradiography. The binding specificity and stability of (18)F-GE180 was further confirmed by a cold tracer competition study and a metabolite study, respectively. Therefore, (18)F-GE180 PET imaging may be useful for longitudinal monitoring of neuroinflammation during AD progression and treatment and may also be useful for other neurodegenerative diseases.
Collapse
|
30
|
|
31
|
|
32
|
Bok S, Wang T, Lee CJ, Jeon SU, Kim YE, Kim J, Hong BJ, Yoon CJ, Kim S, Lee SH, Kim HJ, Kim IH, Kim KH, Ahn GO. In vivo imaging of activated microglia in a mouse model of focal cerebral ischemia by two-photon microscopy. BIOMEDICAL OPTICS EXPRESS 2015; 6:3303-12. [PMID: 26417502 PMCID: PMC4574658 DOI: 10.1364/boe.6.003303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/02/2015] [Accepted: 08/02/2015] [Indexed: 05/19/2023]
Abstract
Microglia are brain resident macrophages rapidly responding to various stimuli to exert appropriate inflammatory responses. Although they have recently been exploited as an attractive candidate for imaging neuroinflammation, it is still difficult to visualize them at the cellular and molecular levels. Here we imaged activated microglia by establishing intracranial window chamber (ICW) in a mouse model of focal cerebral ischemia by using two-photon microscopy (TPM), in vivo. Intravenous injection of fluorescent antibodies allowed us to detect significantly elevated levels of Iba-1 and CD68 positive activated microglia in the ipsilateral compared to the contralateral side of the infarct. We further observed that indomethacin, a non-steroidal anti-inflammatory drug significantly attenuated CD68-positive microglial activation in ICW, which was further confirmed by qRT-PCR biochemical analyses. In conclusion, we believe that in vivo TPM imaging of ICW would be a useful tool to screen for therapeutic interventions lowering microglial activation hence neuroinflammation.
Collapse
Affiliation(s)
- Seoyeon Bok
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Chan-Ju Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Seong-Uk Jeon
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Young-Eun Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Jeongwoo Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Beom-Ju Hong
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Calvin Jinse Yoon
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - Seung-Hoon Lee
- Department of Neurology, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul 110-799, South Korea
| | - Hak Jae Kim
- Department of Radiation Oncology, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul 110-799, South Korea
| | - Il Han Kim
- Department of Radiation Oncology, Seoul National University College of Medicine, 103 Daehak-Ro, Jongno-Gu, Seoul 110-799, South Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| | - G-One Ahn
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784, South Korea
| |
Collapse
|
33
|
The relationship between serial [(18) F]PBR06 PET imaging of microglial activation and motor function following stroke in mice. Mol Imaging Biol 2015; 16:821-9. [PMID: 24865401 DOI: 10.1007/s11307-014-0745-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Using [(18) F]PBR06 positron emission tomography (PET) to characterize the time course of stroke-associated neuroinflammation (SAN) in mice, to evaluate whether brain microglia influences motor function after stroke, and to demonstrate the use of [(18) F]PBR06 PET as a therapeutic assessment tool. PROCEDURES Stroke was induced by transient middle cerebral artery occlusion (MCAO) in Balb/c mice (control, stroke, and stroke with poststroke minocycline treatment). [18 F]PBR06 PET/CT imaging, rotarod tests, and immunohistochemistry (IHC) were performed 3, 11, and 22 days poststroke induction (PSI). RESULTS The stroke group exhibited significantly increased microglial activation, and impaired motor function. Peak microglial activation was 11 days PSI. There was a strong association between microglial activation, motor function, and microglial protein expression on IHC. Minocycline significantly reduced microglial activation and improved motor function by day 22 PSI. CONCLUSION [18 F]PBR06 PET imaging noninvasively characterizes the time course of SAN, and shows increased microglial activation is associated with decreased motor function.
Collapse
|
34
|
Guo Y, Kalathur RC, Liu Q, Kloss B, Bruni R, Ginter C, Kloppmann E, Rost B, Hendrickson WA. Protein structure. Structure and activity of tryptophan-rich TSPO proteins. Science 2015; 347:551-5. [PMID: 25635100 DOI: 10.1126/science.aaa1534] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Translocator proteins (TSPOs) bind steroids and porphyrins, and they are implicated in many human diseases, for which they serve as biomarkers and therapeutic targets. TSPOs have tryptophan-rich sequences that are highly conserved from bacteria to mammals. Here we report crystal structures for Bacillus cereus TSPO (BcTSPO) down to 1.7 Å resolution, including a complex with the benzodiazepine-like inhibitor PK11195. We also describe BcTSPO-mediated protoporphyrin IX (PpIX) reactions, including catalytic degradation to a previously undescribed heme derivative. We used structure-inspired mutations to investigate reaction mechanisms, and we showed that TSPOs from Xenopus and man have similar PpIX-directed activities. Although TSPOs have been regarded as transporters, the catalytic activity in PpIX degradation suggests physiological importance for TSPOs in protection against oxidative stress.
Collapse
Affiliation(s)
- Youzhong Guo
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ravi C Kalathur
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Qun Liu
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA. New York Structural Biology Center, Synchrotron Beamlines, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Brian Kloss
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Renato Bruni
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Christopher Ginter
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Edda Kloppmann
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA. Department of Informatics, Bioinformatics and Computational Biology, Technische Universität München, Garching 85748, Germany
| | - Burkhard Rost
- The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA. Department of Informatics, Bioinformatics and Computational Biology, Technische Universität München, Garching 85748, Germany
| | - Wayne A Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA. The New York Consortium on Membrane Protein Structure (NYCOMPS), New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA. New York Structural Biology Center, Synchrotron Beamlines, Brookhaven National Laboratory, Upton, NY 11973, USA. Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
35
|
James ML, Belichenko NP, Nguyen TVV, Andrews LE, Ding Z, Liu H, Bodapati D, Arksey N, Shen B, Cheng Z, Wyss-Coray T, Gambhir SS, Longo FM, Chin FT. PET imaging of translocator protein (18 kDa) in a mouse model of Alzheimer's disease using N-(2,5-dimethoxybenzyl)-2-18F-fluoro-N-(2-phenoxyphenyl)acetamide. J Nucl Med 2015; 56:311-6. [PMID: 25613536 DOI: 10.2967/jnumed.114.141648] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Herein we aimed to evaluate the utility of N-(2,5-dimethoxybenzyl)-2-(18)F-fluoro-N-(2-phenoxyphenyl)acetamide ((18)F-PBR06) for detecting alterations in translocator protein (TSPO) (18 kDa), a biomarker of microglial activation, in a mouse model of Alzheimer's disease (AD). METHODS Wild-type (wt) and AD mice (i.e., APP(L/S)) underwent (18)F-PBR06 PET imaging at predetermined time points between the ages of 5-6 and 15-16 mo. MR images were fused with PET/CT data to quantify (18)F-PBR06 uptake in the hippocampus and cortex. Ex vivo autoradiography and TSPO/CD68 immunostaining were also performed using brain tissue from these mice. RESULTS PET images showed significantly higher accumulation of (18)F-PBR06 in the cortex and hippocampus of 15- to 16-mo-old APP(L/S) mice than age-matched wts (cortex/muscle: 2.43 ± 0.19 vs. 1.55 ± 0.15, P < 0.005; hippocampus/muscle: 2.41 ± 0.13 vs. 1.55 ± 0.12, P < 0.005). And although no significant difference was found between wt and APP(L/S) mice aged 9-10 mo or less using PET (P = 0.64), we were able to visualize and quantify a significant difference in (18)F-PBR06 uptake in these mice using autoradiography (cortex/striatum: 1.13 ± 0.04 vs. 0.96 ± 0.01, P < 0.05; hippocampus/striatum: 1.266 ± 0.003 vs. 1.096 ± 0.017, P < 0.001). PET results for 15- to 16-mo-old mice correlated well with autoradiography and immunostaining (i.e., increased (18)F-PBR06 uptake in brain regions containing elevated CD68 and TSPO staining in APP(L/S) mice, compared with wts). CONCLUSION (18)F-PBR06 shows great potential as a tool for visualizing TSPO/microglia in the progression and treatment of AD.
Collapse
Affiliation(s)
- Michelle L James
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and
| | - Thuy-Vi V Nguyen
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and
| | - Lauren E Andrews
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Zhaoqing Ding
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and Veterans Administration Palo Alto Health Care System, Palo Alto, California
| | - Hongguang Liu
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Deepika Bodapati
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Natasha Arksey
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Bin Shen
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Zhen Cheng
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Tony Wyss-Coray
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and Veterans Administration Palo Alto Health Care System, Palo Alto, California
| | - Sanjiv S Gambhir
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, California; and
| | - Frederick T Chin
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), Stanford University, Stanford, California
| |
Collapse
|
36
|
Wang Y, Yue X, Kiesewetter DO, Wang Z, Lu J, Niu G, Teng G, Chen X. [(18)F]DPA-714 PET imaging of AMD3100 treatment in a mouse model of stroke. Mol Pharm 2014; 11:3463-70. [PMID: 25157648 PMCID: PMC4186675 DOI: 10.1021/mp500234d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Chemokine
receptor 4 and stromal-cell-derived factor 1 have been
found to be related to the initiation of neuroinflammation in ischemic
brain. Herein, we aimed to monitor the changes of neuorinflammation
after AMD3100 treatment using a translocator protein (TSPO) specific
PET tracer in a mouse model of stroke. The transient MCAO model was
established with Balb/C mice. The success of the model was confirmed
by magnetic resonance imaging and FDG PET. The treatment started the
same day after surgery via daily intraperitoneal injection of 1 mg
of AMD3100/kg for three consecutive days. [18F]DPA-714
was used as the TSPO imaging tracer. In vivo PET
was performed at different time points after surgery in both control
and treated mice. Ex vivo histological and immunofluorescence
staining of brain slices was performed to confirm the lesion site
and inflammatory cell activation. The TSPO level was also evaluated
using Western blotting. Longitudinal PET scans revealed that the level
of [18F]DPA-714 uptake was significantly increased in the
ischemic brain area with a peak accumulation at around day 10 after
surgery, and the level of uptake remained high until day 16. The in vivo PET data were consistent with those from ex vivo immunofluorescence staining. After AMD3100 treatment,
the signal intensity was significantly decreased compared with that
of normal saline-treated control group. In conclusion, TSPO-targeted
PET imaging using [18F]DPA-714 can be used to monitor inflammatory
response after stroke and provide a useful method for evaluating the
efficacy of anti-inflammation treatment.
Collapse
Affiliation(s)
- Yu Wang
- Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University , Nanjing 210009, China
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Rapôso C, Luna RLDA, Nunes AKS, Thomé R, Peixoto CA. Role of iNOS-NO-cGMP signaling in modulation of inflammatory and myelination processes. Brain Res Bull 2014; 104:60-73. [PMID: 24727400 DOI: 10.1016/j.brainresbull.2014.04.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 03/27/2014] [Accepted: 04/03/2014] [Indexed: 01/25/2023]
Abstract
Nitric oxide (NO) is the main activator of the soluble guanylate cyclase (sGC)-guanosine 3'5' cyclic monophosphate (cGMP) pathway. The level of cGMP is regulated by phosphodiesterases (PDEs), which break down cGMP. It has been reported that levels of NO in the central nervous system (CNS) can greatly increase during demyelination and/or neuroinflammation. Controversially, in demyelination models, mice without iNOS may develop more severe cases of disease. Furthermore, cGMP accumulation caused by PDE inhibitors has an anti-inflammatory/neuroprotective effect in MS-models. The role of the NO-cGMP pathway in the nervous tissue is, therefore, complex and not fully understood. The aim of the present study was to contribute to existing knowledge of the role of this pathway in the CNS. Wild type (WT - C57BL/6) and iNOS(-/-) animals were treated with sildenafil (25mg/kg) for 8 weeks. Control animals were not treated. VCAM and ICAM (adhesion proteins), GFAP and Iba-1 (astrocyte and microglia markers, respectively), PKG (cGMP-dependent protein kinase), sGC, eNOS (constitutive endothelial NO sinthase) and GSTpi (a marker of mature oligodendrocytes) were evaluated in the cerebellum using immunohistochemistry or western blotting. Myelin was assessed by luxol fast blue staining and electron transmission microscopy. Treatment with sildenafil reduced ICAM and VCAM levels (anti-inflammatory effect) and increased GFAP and Iba-1 expression (clearance phenotype) in WT animals. The expression of VCAM, ICAM, GFAP, PKG and sGC was lower in iNOS(-/-) mice than in WT control animals. The treatment of iNOS(-/-) animals with sildenafil resulted in an increase of all proteins (pro-inflammatory effect). There was overexpression of eNOS in untreated iNOS(-/-) mice. The myelin structure of iNOS(-/-) animals was damaged in comparison with WT control. Sildenafil increased GSTpi and resulted in an improved myelin structure in iNOS(-/-) mice. In conclusion, NO-cGMP signaling plays a role in the regulation of inflammation and myelination processes. The accumulation of cGMP produced opposite effects in WT and iNOS(-/-) mice. This can be explained by the overexpression of eNOS in iNOS(-/-) mice, unbalancing cGMP signaling, or cGMP has a dual role in inflammation. Drugs that modulate the NO-sGC-cGMP pathway may be clinically beneficial in the treatment of neuroinflammatory/demyelinating disorders, but further studies of the regulation of this pathway are required.
Collapse
Affiliation(s)
- Catarina Rapôso
- Departamento de Histologia e Embriologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Rua Monteiro Lobato, 255, CEP 13083-862, Campinas, SP, Brazil.
| | - Rayana Leal de Almeida Luna
- Laboratório de Ultraestrutura, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n, CEP 50670-420, Recife, PE, Brazil.
| | - Ana Karolina Santana Nunes
- Laboratório de Ultraestrutura, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n, CEP 50670-420, Recife, PE, Brazil.
| | - Rodolfo Thomé
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Rua Monteiro Lobato, 255, CEP 13083-862, Campinas, SP, Brazil.
| | - Christina Alves Peixoto
- Laboratório de Ultraestrutura, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n, CEP 50670-420, Recife, PE, Brazil.
| |
Collapse
|