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Jonker I, Doorduin J, Knegtering H, van't Hag E, Dierckx RA, de Vries EFJ, Schoevers RA, Klein HC. Antiviral treatment in schizophrenia: a randomized pilot PET study on the effects of valaciclovir on neuroinflammation. Psychol Med 2023; 53:7087-7095. [PMID: 37016791 PMCID: PMC10719624 DOI: 10.1017/s0033291723000430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 01/22/2023] [Accepted: 02/03/2023] [Indexed: 04/06/2023]
Abstract
BACKGROUND Patients with schizophrenia experience cognitive impairment, which could be related to neuroinflammation in the hippocampus. The cause for such hippocampal inflammation is still unknown, but it has been suggested that herpes virus infection is involved. This study therefore aimed to determine whether add-on treatment of schizophrenic patients with the anti- viral drug valaciclovir would reduce hippocampal neuroinflammation and consequently improve cognitive symptoms. METHODS We performed a double-blind monocenter study in 24 male and female patients with schizophrenia, experiencing active psychotic symptoms. Patients were orally treated with the anti-viral drug valaciclovir for seven consecutive days (8 g/day). Neuroinflammation was measured with Positron Emission Tomography using the translocator protein ligand [11C]-PK11195, pre-treatment and at seven days post-treatment, as were psychotic symptoms and cognition. RESULTS Valaciclovir treatment resulted in reduced TSPO binding (39%) in the hippocampus, as well as in the brainstem, frontal lobe, temporal lobe, parahippocampal gyrus, amygdala, parietal lobe, occipital lobe, insula and cingulate gyri, nucleus accumbens and thalamus (31-40%) when using binding potential (BPND) as an outcome. With total distribution volume (VT) as outcome we found essentially the same results, but associations only approached statistical significance (p = 0.050 for hippocampus). Placebo treatment did not affect neuroinflammation. No effects of valaciclovir on psychotic symptoms or cognitive functioning were found. CONCLUSION We found a decreased TSPO binding following antiviral treatment, which could suggest a viral underpinning of neuroinflammation in psychotic patients. Whether this reduced neuroinflammation by treatment with valaciclovir has clinical implications and is specific for schizophrenia warrants further research.
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Affiliation(s)
- Iris Jonker
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Henderikus Knegtering
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Lentis Mental Health Institution, Groningen, The Netherlands
| | - Erna van't Hag
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rudi A. Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Erik F. J. de Vries
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Robert A. Schoevers
- Department of Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Hans C. Klein
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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Ekblad LL, Tuisku J, Koivumäki M, Helin S, Rinne JO, Snellman A. Insulin resistance and body mass index are associated with TSPO PET in cognitively unimpaired elderly. J Cereb Blood Flow Metab 2023; 43:1588-1600. [PMID: 37113066 PMCID: PMC10414007 DOI: 10.1177/0271678x231172519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/27/2023] [Accepted: 04/01/2023] [Indexed: 04/29/2023]
Abstract
Metabolic risk factors are associated with peripheral low-grade inflammation and an increased risk for dementia. We evaluated if metabolic risk factors i.e. insulin resistance, body mass index (BMI), serum cholesterol values, or high sensitivity C-reactive protein associate with central inflammation or beta-amyloid (Aβ) accumulation in the brain, and if these associations are modulated by APOE4 gene dose. Altogether 60 cognitively unimpaired individuals (mean age 67.7 years (SD 4.7); 63% women; 21 APOE3/3, 20 APOE3/4 and 19 APOE4/4) underwent positron emission tomography with [11C]PK11195 targeting TSPO (18 kDa translocator protein) and [11C]PIB targeting fibrillar Aβ. [11C]PK11195 distribution value ratios and [11C]PIB standardized uptake values were calculated in a cortical composite region of interest typical for Aβ accumulation in Alzheimer's disease. Associations between metabolic risk factors, [11C]PK11195, and [11C]PIB uptake were evaluated with linear models adjusted for age and sex. Higher logarithmic HOMA-IR (standardized beta 0.40, p = 0.002) and BMI (standardized beta 0.27, p = 0.048) were associated with higher TSPO availability. Voxel-wise analyses indicated that this association was mainly seen in the parietal cortex. Higher logarithmic HOMA-IR was associated with higher [11C]PIB (standardized beta 0.44, p = 0.02), but only in APOE4/4 homozygotes. BMI and HOMA-IR seem to influence TSPO availability in the brain.
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Affiliation(s)
- Laura L Ekblad
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Jouni Tuisku
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Mikko Koivumäki
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Semi Helin
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Juha O Rinne
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
- InFLAMES Reseach Flagship Center, University of Turku, Turku, Finland
| | - Anniina Snellman
- Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
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3
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Steidemann MM, Liu J, Bayes K, Castro LP, Ferguson-Miller S, LaPres JJ. Evidence for crosstalk between the aryl hydrocarbon receptor and the translocator protein in mouse lung epithelial cells. Exp Cell Res 2023; 429:113617. [PMID: 37172753 DOI: 10.1016/j.yexcr.2023.113617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/07/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Cellular homeostasis requires the use of multiple environmental sensors that can respond to a variety of endogenous and exogenous compounds. The aryl hydrocarbon receptor (AHR) is classically known as a transcription factor that induces drug metabolizing enzymes when bound to toxicants such as 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD). The receptor has a growing number of putative endogenous ligands, such as tryptophan, cholesterol, and heme metabolites. Many of these compounds are also linked to the translocator protein (TSPO), an outer mitochondrial membrane protein. Given a portion of the cellular pool of the AHR has also been localized to mitochondria and the overlap in putative ligands, we tested the hypothesis that crosstalk exists between the two proteins. CRISPR/Cas9 was used to create knockouts for AHR and TSPO in a mouse lung epithelial cell line (MLE-12). WT, AHR-/-, and TSPO-/- cells were then exposed to AHR ligand (TCDD), TSPO ligand (PK11195), or both and RNA-seq was performed. More mitochondrial-related genes were altered by loss of both AHR and TSPO than would have been expected just by chance. Some of the genes altered included those that encode for components of the electron transport system and the mitochondrial calcium uniporter. Both proteins altered the activity of the other as AHR loss caused the increase of TSPO at both the mRNA and protein level and loss of TSPO significantly increased the expression of classic AHR battery genes after TCDD treatment. This research provides evidence that AHR and TSPO participate in similar pathways that contribute to mitochondrial homeostasis.
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Affiliation(s)
- Michelle M Steidemann
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Kalin Bayes
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - Lizbeth P Castro
- Department of Cell and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States
| | - John J LaPres
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, United States.
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Hamilton J, Nguyen C, McAvoy M, Roeder N, Richardson B, Quattrin T, Hajnal A, Thanos PK. Calorie restriction, but not Roux-en-Y gastric bypass surgery, increases [ 3 H] PK11195 binding in a rat model of obesity. Synapse 2023; 77:e22258. [PMID: 36352528 DOI: 10.1002/syn.22258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 10/05/2022] [Accepted: 10/09/2022] [Indexed: 11/11/2022]
Abstract
Roux-en-Y gastric bypass surgery (RYGB) remains an effective weight-loss method used to treat obesity. While it is successful in combating obesity, there are many lingering questions related to the changes in the brain following RYGB surgery, one of them being its effects on neuroinflammation. While it is known that chronic high-fat diet (HFD) contributes to obesity and neuroinflammation, it remains to be understood whether bariatric surgery can ameliorate diet-induced inflammatory responses. To examine this, rats were assigned to either a normal diet (ND) or a HFD for 8 weeks. Rats fed a HFD were split into the following groups: sham surgery with ad libitum access to HFD (sham-HF); sham surgery with calorie-restricted HFD (sham-FR); RYGB surgery with ad libitum access to HFD (RYGB). Following sham or RYGB surgeries, rats were maintained on their diets for 9 weeks before being euthanized. [3 H] PK11195 autoradiography was then performed on fresh-frozen brain tissue in order to measure activated microglia. Sham-FR rats showed increased [3 H] PK11195 binding in the amygdala (63%), perirhinal (60%), and ectorhinal cortex (53%) compared with the ND rats. Obese rats who had the RYGB surgery did not show this increased inflammatory effect. Since the sham-FR and RYGB rats were fed the same amount of HFD, the surgery itself seems responsible for this attenuation in [3 H] PK11195 binding. We speculate that calorie restriction following obese conditions may be seen as a stressor and contribute to inflammation in the brain. Further research is needed to verify this mechanism.
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Affiliation(s)
- John Hamilton
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Cynthia Nguyen
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Margaret McAvoy
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Nicole Roeder
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
| | - Brittany Richardson
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
| | - Teresa Quattrin
- Department of Pediatrics, University at Buffalo, UBMD Pediatrics, JR Oishei Children's Hospital, Buffalo, New York, USA
| | - Andras Hajnal
- Department of Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Panayotis K Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Department of Psychology, University at Buffalo, Buffalo, New York, USA
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Conti E, Grana D, Angiulli F, Karantzoulis A, Villa C, Combi R, Appollonio I, Ferrarese C, Tremolizzo L. TSPO Modulates Oligomeric Amyloid-β-Induced Monocyte Chemotaxis: Relevance for Neuroinflammation in Alzheimer's Disease. J Alzheimers Dis 2023; 95:549-559. [PMID: 37574731 DOI: 10.3233/jad-230239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
BACKGROUND Neuroinflammation is one of the cardinal mechanisms of Alzheimer's disease (AD). with amyloid-β (Aβ) playing a critical role by activating microglia to produce soluble inflammatory mediators, including several chemokines. Peripheral monocytes are, therefore, attracted into the central nervous system (CNS), where they change into blood-born microglia and participate in the attempt of removing toxic Aβ species. The translocator protein-18 kDa (TSPO) is a transmembrane protein overexpressed in response to neuroinflammation and known to regulate human monocyte chemotaxis. OBJECTIVE We aimed to evaluate the role of the oligomeric Aβ1-42 isoform at inducing peripheral monocyte chemotaxis, and the possible involvement of TSPO in this process. METHODS In vitro cell lines, and ex vivo monocytes from consecutive AD patients (n = 60), and comparable cognitively intact controls (n = 30) were used. Chemotaxis analyses were carried out through both μ-slide chambers and Boyden assays, using 125 pM oligomeric Aβ1-42 as chemoattractant. TSPO agonists and antagonists were tested (Ro5-4864, Emapunil, PK11195). RESULTS Oligomeric Aβ directly promoted chemotaxis in all our models. Interestingly, AD monocytes displayed a stronger response (about twofold) with respect to controls. Aβ-induced chemotaxis was prevented by the TSPO antagonist PK11195; the expression of the TSPO and of the C-C chemokine receptor type 2 (CCR2) was unchanged by drug exposure. CONCLUSION Oligomeric Aβ1-42 is able to recruit peripheral monocytes, and we provide initial evidence sustaining a role for TSPO in modulating this process. This data may be of value for future therapeutic interventions aimed at modulating monocytes motility toward the CNS.
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Affiliation(s)
- Elisa Conti
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
| | - Denise Grana
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
| | - Federica Angiulli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
| | - Aristotelis Karantzoulis
- Milan Center for Neuroscience (NeuroMi), Italy
- Memory Clinic, Neurology Unit, IRCCS "San Gerardo dei Tintori", Monza, Italy
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
| | - Romina Combi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
| | - Ildebrando Appollonio
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
- Memory Clinic, Neurology Unit, IRCCS "San Gerardo dei Tintori", Monza, Italy
| | - Carlo Ferrarese
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
- Memory Clinic, Neurology Unit, IRCCS "San Gerardo dei Tintori", Monza, Italy
| | - Lucio Tremolizzo
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Milan Center for Neuroscience (NeuroMi), Italy
- Memory Clinic, Neurology Unit, IRCCS "San Gerardo dei Tintori", Monza, Italy
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Hines RM, Aquino EA, Khumnark MI, Dávila MP, Hines DJ. Comparative Assessment of TSPO Modulators on Electroencephalogram Activity and Exploratory Behavior. Front Pharmacol 2022; 13:750554. [PMID: 35444539 PMCID: PMC9015213 DOI: 10.3389/fphar.2022.750554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/07/2022] [Indexed: 01/04/2023] Open
Abstract
Network communication in the CNS relies upon multiple neuronal and glial signaling pathways. In addition to synaptic transmission, other organelles such as mitochondria play roles in cellular signaling. One highly conserved mitochondrial signaling mechanism involves the 18 kDa translocator protein (TSPO) of the outer mitochondrial membrane. Originally, TSPO was identified as a binding site for benzodiazepines in the periphery. It was later discovered that TSPO is found in mitochondria, including in CNS cells. TSPO is implicated in multiple cellular processes, including the translocation of cholesterol and steroidogenesis, porphyrin transport, cellular responses to stress, inflammation, and tumor progression. Yet the impacts of modulating TSPO signaling on network activity and behavioral performance have not been characterized. In the present study, we assessed the effects of TSPO modulators PK11195, Ro5-4864, and XBD-173 via electroencephalography (EEG) and the open field test (OFT) at low to moderate doses. Cortical EEG recordings revealed increased power in the δ and θ frequency bands after administration of each of the three modulators, as well as compound- and dose-specific changes in α and γ. Behaviorally, these compounds reduced locomotor activity in the OFT in a dose-dependent manner, with XBD-173 having the subtlest behavioral effects while still strongly modulating the EEG. These findings indicate that TSPO modulators, despite their diversity, exert similar effects on the EEG while displaying a range of sedative/hypnotic effects at moderate to high doses. These findings bring us one step closer to understanding the functions of TSPO in the brain and as a target in CNS disease.
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Affiliation(s)
- Rochelle M Hines
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Elaine A Aquino
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Matthew I Khumnark
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Maria P Dávila
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Dustin J Hines
- Department of Psychology, Psychological and Brain Sciences & Interdisciplinary Neuroscience Programs, University of Nevada, Las Vegas, Las Vegas, NV, United States
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Kang Y, Rúa SMH, Kaunzner UW, Perumal J, Nealon N, Qu W, Kothari PJ, Vartanian T, Kuceyeski A, Gauthier SA. A Multi-Ligand Imaging Study Exploring GABAergic Receptor Expression and Inflammation in Multiple Sclerosis. Mol Imaging Biol 2021; 22:1600-1608. [PMID: 32394283 DOI: 10.1007/s11307-020-01501-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE The γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter and essential for normal brain function. The GABAergic system has been shown to have immunomodulatory effects and respond adaptively to excitatory toxicity. The association of the GABAergic system and inflammation in patients with multiple sclerosis (MS) remains unknown. In this pilot study, the in vivo relationship between GABAA binding and the innate immune response is explored using positron emission tomography (PET) with [11C] flumazenil (FMZ) and [11C]-PK11195 PET (PK-PET), a measure of activated microglia/macrophages. PROCEDURES Sixteen MS patients had dynamic FMZ-PET and PK-PET imaging. Ten age-matched healthy controls (HC) had a single FMZ-PET. GABAA receptor binding was calculated using Logan reference model with the pons as reference. Distribution of volume ratio (VTr) for PK-PET was calculated using image-derived input function. A hierarchical linear model was fitted to assess the linear association between PK-PET and FMZ-PET among six cortical regions of interest. RESULTS GABAA receptor binding was higher throughout the cortex in MS patients (5.72 ± 0.91) as compared with HC (4.70 ± 0.41) (p = 0.002). A significant correlation was found between FMZ binding and PK-PET within the cortex (r = 0.61, p < 0.001) and among the occipital (r = 0.61, p = 0.012), parietal (r = 0.49, p = 0.041), and cingulate (r = 0.32, p = 0.006) regions. CONCLUSIONS A higher GABAA receptor density in MS subjects compared with HC was observed and correlated with innate immune activity. Our observations demonstrate that immune-driven GABAergic abnormalities may be present in MS.
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Affiliation(s)
- Yeona Kang
- Department of Radiology, Weill Cornell Medicine, New York, NY, 10021, USA.,Department of Mathematics, Howard University, Washington, D.C, 20059, USA
| | - Sandra Milena Hurtado Rúa
- Department of Mathematics and Statistics, College of Science and Health Professions, Cleveland State University, Cleveland, OH, 44115, USA
| | - Ulrike W Kaunzner
- Department of Neurology, Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Jai Perumal
- Department of Neurology, Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Nancy Nealon
- Department of Neurology, Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Wenchao Qu
- Department of Radiology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Paresh J Kothari
- Department of Radiology, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Timothy Vartanian
- Department of Neurology, Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York, NY, 10021, USA.,Feil Family Brain and Mind Institute, Weill Cornell, New York, NY, 10021, USA
| | - Amy Kuceyeski
- Department of Radiology, Weill Cornell Medicine, New York, NY, 10021, USA.,Feil Family Brain and Mind Institute, Weill Cornell, New York, NY, 10021, USA
| | - Susan A Gauthier
- Department of Radiology, Weill Cornell Medicine, New York, NY, 10021, USA. .,Department of Neurology, Judith Jaffe Multiple Sclerosis Center, Weill Cornell Medicine, New York, NY, 10021, USA. .,Feil Family Brain and Mind Institute, Weill Cornell, New York, NY, 10021, USA.
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Seidlmayer LK, Hanson BJ, Thai PN, Schaefer S, Bers DM, Dedkova EN. PK11195 Protects From Cell Death Only When Applied During Reperfusion: Succinate-Mediated Mechanism of Action. Front Physiol 2021; 12:628508. [PMID: 34149440 PMCID: PMC8212865 DOI: 10.3389/fphys.2021.628508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Aim: Reperfusion after myocardial ischemia causes cellular injury, in part due to changes in mitochondrial Ca2+ handling, oxidative stress, and myocyte energetics. We have previously shown that the 18-kDa translocator protein of the outer mitochondrial membrane (TSPO) can modulate Ca2+ handling. Here, we aim to evaluate the role of the TSPO in ischemia/reperfusion (I/R) injury. Methods: Rabbit ventricular myocytes underwent simulated acute ischemia (20 min) and reperfusion (at 15 min, 1 h, and 3 h) in the absence and presence of 50 μM PK11195, a TSPO inhibitor. Cell death was measured by lactate dehydrogenase (LDH) assay, while changes in mitochondrial Ca2+, membrane potential (ΔΨm), and reactive oxygen species (ROS) generation were monitored using confocal microscopy in combination with fluorescent indicators. Substrate utilization was measured with Biolog mitochondrial plates. Results: Cell death was increased by ~200% following I/R compared to control untreated ventricular myocytes. Incubation with 50 μM PK11195 during both ischemia and reperfusion did not reduce cell death but increased mitochondrial Ca2+ uptake and ROS generation. However, application of 50 μM PK11195 only at the onset and during reperfusion effectively protected against cell death. The large-scale oscillations in ΔΨm observed after ~1 h of reperfusion were significantly delayed by 1 μM cyclosporin A and almost completely prevented by 50 μM PK11195 applied during 3 h of reperfusion. After an initial increase, mitochondrial Ca2+, measured with Myticam, rapidly declined during 3 h of reperfusion after the initial transient increase. This decline was prevented by application of PK11195 at the onset and during reperfusion. PK11195 prevented a significant increase in succinate utilization following I/R and succinate-induced forward-mode ROS generation. Treatment with PK11195 was also associated with a significant increase in glutamate and a decrease in leucine utilization. Conclusion: PK11195 administered specifically at the moment of reperfusion limited ROS-induced ROS release and cell death, likely in part, by a shift from succinate to glutamate utilization. These data demonstrate a unique mechanism to limit cardiac injury after I/R.
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Affiliation(s)
- Lea K Seidlmayer
- Department of Cardiology, University Hospital Olbenburg, Olbenburg, Germany
| | - Benjamin J Hanson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Phung N Thai
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Saul Schaefer
- Department of Internal Medicine, Division of Cardiovascular Medicine, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Donald M Bers
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Elena N Dedkova
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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9
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Lai HTT, Giorgetti A, Rossetti G, Nguyen TT, Carloni P, Kranjc A. The Interplay of Cholesterol and Ligand Binding in hTSPO from Classical Molecular Dynamics Simulations. Molecules 2021; 26:1250. [PMID: 33652554 DOI: 10.3390/molecules26051250] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/28/2021] [Accepted: 02/03/2021] [Indexed: 12/23/2022] Open
Abstract
The translocator protein (TSPO) is a 18kDa transmembrane protein, ubiquitously present in human mitochondria. It is overexpressed in tumor cells and at the sites of neuroinflammation, thus representing an important biomarker, as well as a promising drug target. In mammalian TSPO, there are cholesterol–binding motifs, as well as a binding cavity able to accommodate different chemical compounds. Given the lack of structural information for the human protein, we built a model of human (h) TSPO in the apo state and in complex with PK11195, a molecule routinely used in positron emission tomography (PET) for imaging of neuroinflammatory sites. To better understand the interactions of PK11195 and cholesterol with this pharmacologically relevant protein, we ran molecular dynamics simulations of the apo and holo proteins embedded in a model membrane. We found that: (i) PK11195 stabilizes hTSPO structural fold; (ii) PK11195 might enter in the binding site through transmembrane helices I and II of hTSPO; (iii) PK11195 reduces the frequency of cholesterol binding to the lower, N–terminal part of hTSPO in the inner membrane leaflet, while this impact is less pronounced for the upper, C–terminal part in the outer membrane leaflet, where the ligand binding site is located; (iv) very interestingly, cholesterol most frequently binds simultaneously to the so-called CRAC and CARC regions in TM V in the free form (residues L150–X–Y152–X(3)–R156 and R135–X(2)–Y138–X(2)–L141, respectively). However, when the protein is in complex with PK11195, cholesterol binds equally frequently to the CRAC–resembling motif that we observed in TM I (residues L17–X(2)–F20–X(3)–R24) and to CRAC in TM V. We expect that the CRAC–like motif in TM I will be of interest in future experimental investigations. Thus, our MD simulations provide insight into the structural features of hTSPO and the previously unknown interplay between PK11195 and cholesterol interactions with this pharmacologically relevant protein.
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Lan N, Liu Y, Juan Z, Zhang R, Ma B, Xie K, Sun L, Feng H, Sun M, Liu J. The TSPO-specific Ligand PK11195 Protects Against LPS-Induced Cognitive Dysfunction by Inhibiting Cellular Autophagy. Front Pharmacol 2021; 11:615543. [PMID: 33708121 PMCID: PMC7941270 DOI: 10.3389/fphar.2020.615543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Perioperative neurocognitive disorders (PND) is a common postoperative neurological complication. Neuroinflammation is a major cause that leads to PND. Autophagy, an intracellular process of lysosomal degradation, plays an important role in the development and maintenance of nervous system. PK11195 is a classic translocator protein (TSPO) ligand, which can improve the cognitive function of rats. In this study, we evaluate the protective effect of PK11195 on the learning and memory of rats. A rat model of lipopolysaccharide (LPS)-induced cognitive dysfunction was established by intraperitoneal injection of LPS. Morris Water Maze (MWM), Western blot, qRT-PCR, confocal microscopy and transmission electron microscopy (TEM) were used to study the role of TSPO-specific ligand PK11195 in LPS-activated mitochondrial autophagy in rat hippocampus. We found that PK11195 ameliorated LPS-induced learning and memory impairment, as indicated by decreased escape latencies, swimming distances and increased target quadrant platform crossing times and swimming times during MWM tests. TSPO, ATG7, ATG5, LC3B and p62 protein and mRNA expression increased in the hippocampus of PND model rats. The hippocampal microglia of PND model rats also have severe mitochondrial damage, and a large number of autophagosomes and phagocytic vesicles can be seen. PK11195 pretreatment significantly decreased the expression of TSPO, ATG7, ATG5, LC3B and p62 protein and mRNA, as well as mitochondrial damage. These findings suggested that PK11195 may alleviate the damage of LPS-induced cognitive dysfunction of rats by inhibiting microglia activation and autophagy.
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Affiliation(s)
- Nannan Lan
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Yongxin Liu
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Zhaodong Juan
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Rui Zhang
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Baoyu Ma
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Keliang Xie
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Lina Sun
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Hao Feng
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Meng Sun
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Jianfeng Liu
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
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Feng H, Liu Y, Zhang R, Liang Y, Sun L, Lan N, Ma B. TSPO Ligands PK11195 and Midazolam Reduce NLRP3 Inflammasome Activation and Proinflammatory Cytokine Release in BV-2 Cells. Front Cell Neurosci 2020; 14:544431. [PMID: 33362467 PMCID: PMC7759202 DOI: 10.3389/fncel.2020.544431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation related to microglial activation plays an important role in neurodegenerative diseases. Translocator protein 18 kDa (TSPO), a biomarker of reactive gliosis, its ligands can reduce neuroinflammation and can be used to treat neurodegenerative diseases. Therefore, we explored whether TSPO ligands exert an anti-inflammatory effect by affecting the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome, thereby inhibiting the release of inflammatory cytokines in microglial cells. In the present study, BV-2 cells were exposed to lipopolysaccharide (LPS) for 6 h to induce an inflammatory response. We found that the levels of reactive oxygen species (ROS), NLRP3 inflammasome, interleukin-1β (IL-1β), and interleukin-18 (IL-18) were significantly increased. However, pretreatment with TSPO ligands inhibited BV-2 microglial and NLRP3 inflammasome activation and significantly reduced the levels of ROS, IL-1β, and IL-18. Furthermore, a combination of LPS and ATP was used to activate the NLRP3 inflammasome. Both pretreatment and post-treatment with TSPO ligand can downregulate the activation of NLRP3 inflammasome and IL-1β expression. Finally, we found that TSPO was involved in the regulation of NLRP3 inflammasome with TSPO ligands treatment in TSPO knockdown BV2 cells. Collectively, these results indicate that TSPO ligands are promising targets to control microglial reactivity and neuroinflammatory diseases.
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Affiliation(s)
- Hao Feng
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Yongxin Liu
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Rui Zhang
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Yingxia Liang
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Lina Sun
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Nannan Lan
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
| | - Baoyu Ma
- Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, School of Anesthesiology, Weifang Medical University, Weifang, China
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Gudasheva TA, Deeva OA, Pantileev AS, Mokrov GV, Rybina IV, Yarkova MA, Seredenin SB. The New Dipeptide TSPO Ligands: Design, Synthesis and Structure-Anxiolytic Activity Relationship. Molecules 2020; 25:E5132. [PMID: 33158242 DOI: 10.3390/molecules25215132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/28/2020] [Accepted: 11/02/2020] [Indexed: 11/17/2022] Open
Abstract
The translocator protein (TSPO, 18 kDa) plays an important role in the synthesis of neurosteroids by promoting the transport of cholesterol from the outer to the inner mitochondrial membrane, which is the rate-limiting step in neurosteroidogenesis. Stimulation of TSPO by appropriate ligands increases the level of neurosteroids. The present study describes the design, synthesis and investigation of anxiolytic-like effects of a series of N-acyl-tryptophanyl-containing dipeptides. These novel dipeptide TSPO ligands were designed with the original drug-based peptide design strategy using alpidem as non-peptide prototype. The anxiolytic activities were investigated in Balb/C mice using the illuminated open-field and elevated plus-maze tests in outbred laboratory mice ICR (CD-1). Dipeptide GD-102 (N-phenylpropionyl-l-tryptophanyl-l-leucine amide) in the dose range of 0.01-0.5 mg/kg intraperitoneally (i.p.) has a pronounced anxiolytic activity. The anxiolytic effect of GD-102 was abolished by PK11195, a specific TSPO antagonist. The structure-activity relationship study made it possible to identify a pharmacophore fragment for the dipeptide TSPO ligand. It was shown that l,d-diastereomer of GD-102 has no activity, and the d,l-isomer has less pronounced activity. The anxiolytic activity also disappears by replacing the C-amide group with the methyl ester, a free carboxyl group or methylamide. Consecutive replacement of each amino acid residue with glycine showed the importance of each of the amino acid residues in the structure of the ligand. The most active and technologically available compound GD-102, was selected for evaluation as a potential anxiolytic drug.
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Gao ZW, Huang YY, Zhang JQ, Rong JY, Qiao GY, Chen N, Yu GD, Luo M, Liu XF. Paeoniflorin elicits the anti-proliferative effects on glioma cell via targeting translocator protein 18 KDa. J Pharmacol Sci 2020; 145:115-121. [PMID: 33357769 DOI: 10.1016/j.jphs.2020.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/17/2020] [Accepted: 04/08/2020] [Indexed: 10/23/2022] Open
Abstract
As a natural compound isolated from Paeoniae radix, Paeoniflorin (PF) has been shown the antitumor effects in various types of human cancers including glioma, which is one of the serious tumors in central nervous system. Translocator protein 18 KDa (TSPO) has been shown to be relevant to the glioma aetiology. However, the regulation of PF in TSPO and neurosteriods biosynthesis on glioma is still unclear. In the present study, the glioma cell (U87 and U251) were cultured and used to quantify the bindings of PF on TSPO. Results indicated that there was not significant different between IC50 of PF and TSPO ligand PK11195. Moreover, PF exerted the anti-proliferative effects in glioma cell with a dose dependent inhibition from 12.5 to 100 μM in vitro. Consistent with the effects of PK11195, lowered levels on progesterone, allopregnanolone, as well as TSPO mRNA were induced by PF (25 and 50 μM). Furthermore, a xenograft mouse model with U87 cell-derived was significant inhibited by PF treatment, as well as the PK11195 administration. These results demonstrate that PF exerts its antitumor effects associated with the TSPO and neurosteroids biosynthesis in glioma cells could be a promising therapeutic agent for glioma therapy.
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Affiliation(s)
- Zhuo-Wei Gao
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China; School of Traditional Chinese Medicine, Southern Medical University Guangzhou, Guangdong, 510515, China
| | - Yu-Yun Huang
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Jia-Qi Zhang
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Jing-Yu Rong
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Guan-Ying Qiao
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Nan Chen
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Guo-Dong Yu
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China.
| | - Min Luo
- Nanfang Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Xiao-Fen Liu
- The Fifth Affiliated Hospital of Southern Medical University, China Guangzhou, Guangdong, 510900, China.
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Ye C, Lin L, Zhang P, Chen Y, Huang J, Lin X. The protective effect of PK11195 on D-galactose-induced amnestic mild cognitive impairment in rats. Ann Transl Med 2020; 8:1190. [PMID: 33241039 PMCID: PMC7576013 DOI: 10.21037/atm-20-6157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background This study aimed to investigate the preventive effect of translocator protein 18kDa (TSPO) ligand PK11195 on amnestic mild cognitive impairment (aMCI), as well as its influence on astrocytes, in order to identify effective ways to prevent aMCI. Methods Male SD rats were randomly divided into control group (n=10), aMCI group (n=10), PK11195 group (n=10), PK11195 + D-gal group (n=10). The preventive effect of PK11195 on aMCI in rats was evaluated. The cognitive function of rats in four different treatment groups was determined using the Morris water maze (MWM), as well as whole-brain pathology and immunofluorescence of rat brain tissue. Results The results of the MWM behavioral test showed that rats pre-treated with PK11195 had improved escape latency and a higher number of platform crossings compared with the aMCI model rats. PK11195 was also shown to prevent the D-galactose (D-gal)-induced senescence of pyramidal cells in the hippocampal CA1 region and to inhibit the apoptosis of astrocytes. At the same time, compared with the aMCI model rats, the TSPO in the brain tissue of rats pretreated with PK11195 had a lower distribution density. Conclusions Our results prove that PK11195 can effectively prevent D-gal-induced decline of learning and memory function as well as inhibit abnormal changes of related cells.
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Affiliation(s)
- Chen Ye
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Lanying Lin
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Peiling Zhang
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Yi Chen
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Jinghao Huang
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
| | - Xianzhong Lin
- Department of Anesthesiology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.,Institute of Anesthesiology, Fujian Medical University, Fuzhou, China
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Ismail R, Parbo P, Madsen LS, Hansen AK, Hansen KV, Schaldemose JL, Kjeldsen PL, Stokholm MG, Gottrup H, Eskildsen SF, Brooks DJ. The relationships between neuroinflammation, beta-amyloid and tau deposition in Alzheimer's disease: a longitudinal PET study. J Neuroinflammation 2020; 17:151. [PMID: 32375809 PMCID: PMC7203856 DOI: 10.1186/s12974-020-01820-6] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 04/17/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The aim of this longitudinal study was to assess with positron emission tomography (PET) the relationship between levels of inflammation and the loads of aggregated β-amyloid and tau at baseline and again after 2 years in prodromal Alzheimer's disease. METHODS Forty-three subjects with mild cognitive impairment (MCI) had serial 11C-PK11195 PET over 2 years to measure inflammation changes, and 11C-PiB PET to determine β-amyloid fibril load; 22 also had serial 18F-Flortaucipir PET to determine tau tangle load. Cortical surface statistical mapping was used to localise areas showing significant changes in tracer binding over time and to interrogate correlations between tracer binding of the tracers at baseline and after 2 years. RESULTS Those MCI subjects with high 11C-PiB uptake at baseline (classified as prodromal Alzheimer's disease) had raised inflammation levels which significantly declined across cortical regions over 2 years although their β-amyloid levels continued to rise. Those MCI cases who had low/normal 11C-PiB uptake at baseline but their levels then rose over 2 years were classified as prodromal AD with low Thal phase 1-2 amyloid deposition at baseline. They showed levels of cortical inflammation which correlated with their rising β-amyloid load. Those MCI cases with baseline low 11C-PiB uptake that remained stable were classified as non-AD, and they showed no correlated inflammation levels. Finally, MCI cases which showed both high 11C-PiB and 18F-Flortaucipir uptake at baseline (MCI due to AD) showed a further rise in their tau tangle load over 2 years with a correlated rise in levels of inflammation. CONCLUSIONS Our baseline and 2-year imaging findings are compatible with a biphasic trajectory of inflammation in Alzheimer's disease: MCI cases with low baseline but subsequently rising β-amyloid load show correlated levels of microglial activation which then later decline when the β-amyloid load approaches AD levels. Later, as tau tangles form in β-amyloid positive MCI cases with prodromal AD, the rising tau load is associated with higher levels of inflammation.
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Affiliation(s)
- Rola Ismail
- Department of Clinical Medicine, PET-Centre, Aarhus University, Aarhus, Denmark.
| | - Peter Parbo
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200, Aarhus N, Denmark
| | | | - Allan K Hansen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200, Aarhus N, Denmark
| | - Kim V Hansen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200, Aarhus N, Denmark
| | - Jeppe L Schaldemose
- Department of Clinical Medicine, PET-Centre, Aarhus University, Aarhus, Denmark
| | - Pernille L Kjeldsen
- Department of Clinical Medicine, PET-Centre, Aarhus University, Aarhus, Denmark
| | - Morten G Stokholm
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, DK-8200, Aarhus N, Denmark
| | - Hanne Gottrup
- Dept. of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Simon F Eskildsen
- Centre of Functionally Integrative Neuroscience (CFIN), Aarhus University, Aarhus, Denmark
| | - David J Brooks
- Department of Clinical Medicine, PET-Centre, Aarhus University, Aarhus, Denmark
- Institute of Neuroscience, University of Newcastle upon Tyne, Tyne, UK
- Department of Medicine, Imperial College London, London, UK
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Jung ME, Metzger DB, Hall J. The long-term but not short-term use of benzodiazepine impairs motoric function and upregulates amyloid β in part through the suppression of translocator protein. Pharmacol Biochem Behav 2020; 191:172873. [PMID: 32105662 DOI: 10.1016/j.pbb.2020.172873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/22/2020] [Accepted: 02/15/2020] [Indexed: 11/24/2022]
Abstract
Many elderly American women use CNS depressant benzodiazepine (BZD) to ameliorate anxiety or insomnia. However, the chronic use of BZD (cBZD) is prevalent, causing adverse effects of BZD that include movement deficit. We previously reported that cBZD upregulates neurotoxic amyloid β42 (Aβ42) and downregulates neuroprotective translocator protein (TSPO) in the cerebellum, the brain area of movement and balance. The aim of the current study is two-fold: 1) to determine a direct effect of TSPO (inhibition) on cBZD-induced Aβ42 and Aβ-associated molecules; Aβ-producing-protein presenilin-1 (PS1) and Aβ-degrading-enzyme neprilysin and 2) to determine whether Aβ42 upregulation and motoric deficit occur upon a long-term (cBZD) rather than a short-term BZD (sBZD) treatment. Old female mice received BZD (lorazepam) for 20 days (cBZD) or 3 days (sBZD) with or without prototype TSPO ligand PK11195 and were tested for motoric performance for 3 days using Rotarod. ELISA was conducted to measure Aβ42 level and neprilysin activity in cerebellum. RT-PCR and immunoblot were conducted to measure the mRNA and protein levels of TSPO, PS1, and neprilysin. cBZD treatment decreased TSPO and neprilysin but increased Aβ42 accompanied by motoric deficit. Chronic PK11195 treatment acted as a TSPO inhibitor by suppressing TSPO expression and mimicked or exacerbated the effects of cBZD on all parameters measured except for PS1. None of the molecular and behavioral changes induced by cBZD were reproduced by sBZD treatment. These data suggest that cBZD upregulates Aβ42 and downregulates neprilysin in part through TSPO inhibition, the mechanisms distinct from sBZD, collectively contributing to motoric deficit.
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Affiliation(s)
- Marianna E Jung
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America.
| | - Daniel B Metzger
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America
| | - James Hall
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America
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Parbo P, Madsen LS, Ismail R, Zetterberg H, Blennow K, Eskildsen SF, Vorup-Jensen T, Brooks DJ. Low plasma neurofilament light levels associated with raised cortical microglial activation suggest inflammation acts to protect prodromal Alzheimer's disease. Alzheimers Res Ther 2020; 12:3. [PMID: 31898549 PMCID: PMC6941285 DOI: 10.1186/s13195-019-0574-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 12/23/2019] [Indexed: 01/08/2023]
Abstract
BACKGROUND Plasma and cerebrospinal fluid levels of neurofilament light (NfL), a marker of axonal degeneration, have previously been reported to be raised in patients with clinically diagnosed Alzheimer's disease (AD). Activated microglia, an intrinsic inflammatory response to brain lesions, are also known to be present in a majority of Alzheimer or mild cognitive impaired (MCI) subjects with raised β-amyloid load on their positron emission tomography (PET) imaging. It is now considered that the earliest phase of inflammation may be protective to the brain, removing amyloid plaques and remodelling synapses. Our aim was to determine whether the cortical inflammation/microglial activation load, measured with the translocator protein marker 11C-PK11195 PET, was correlated with plasma NfL levels in prodromal and early Alzheimer subjects. METHODS Twenty-seven MCI or early AD cases with raised cortical β-amyloid load had 11C-(R)-PK11195 PET, structural and diffusion magnetic resonance imaging, and levels of their plasma NfL measured. Correlation analyses were performed using surface-based cortical statistics. RESULTS Statistical maps localised areas in MCI cases where levels of brain inflammation correlated inversely with plasma NfL levels. These areas were localised in the frontal, parietal, precuneus, occipital, and sensorimotor cortices. Brain inflammation correlated negatively with mean diffusivity (MD) of water with regions overlapping. CONCLUSION We conclude that an inverse correlation between levels of inflammation in cortical areas and plasma NfL levels indicates that microglial activation may initially be protective to axons in AD. This is supported by the finding of an inverse association between cortical water diffusivity and microglial activation in the same regions. Our findings suggest a rationale for stimulating microglial activity in early and prodromal Alzheimer cases-possibly using immunotherapy. Plasma NfL levels could be used as a measure of the protective efficacy of immune stimulation and for monitoring efficacy of putative neuroprotective agents.
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Affiliation(s)
- Peter Parbo
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark. .,Department of Clinical Physiology, Viborg Regional Hospital, Viborg, Denmark.
| | - Lasse Stensvig Madsen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Rola Ismail
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.,UK Dementia Research Institute at UCL, London, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Simon F Eskildsen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Thomas Vorup-Jensen
- Department of Biomedicine/Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Aarhus, Denmark
| | - David J Brooks
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark.,Institute of Neuroscience, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
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Wu LP, Gong ZF, Wang H, Zhou ZS, Zhang MM, Liu C, Ren HM, Yang J, Han Y, Zeng CY. TSPO ligands prevent the proliferation of vascular smooth muscle cells and attenuate neointima formation through AMPK activation. Acta Pharmacol Sin 2020; 41:34-46. [PMID: 31515530 DOI: 10.1038/s41401-019-0293-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/17/2019] [Indexed: 02/06/2023] Open
Abstract
Abnormal growth of the intimal layer of blood vessels (neointima formation) contributes to the progression of atherosclerosis and in-stent restenosis. Recent evidence shows that the 18-kDa translocator protein (TSPO), a mitochondrial membrane protein, is involved in diverse cardiovascular diseases. In this study we investigated the role of endogenous TSPO in neointima formation after angioplasty in vitro and in vivo. We established a vascular injury model in vitro by using platelet-derived growth factor-BB (PDGF-BB) to stimulate rat thoracic aortic smooth muscle cells (A10 cells). We found that treatment with PDGF-BB (1–20 ng/mL) dose-dependently increased TSPO expression in A10 cells, which was blocked in the presence of PKC inhibitor or MAPK inhibitor. Overexpression of TSPO significantly promoted the proliferation and migration in A10 cells, whereas downregulation of TSPO expression by siRNA or treatment with TSPO ligands PK11195 or Ro5-4864 (104 nM) produced the opposite effects. Furthermore, we found that PK11195 (10−104 nM) dose-dependently activated AMPK in A10 cells. PK11195-induced inhibition on the proliferation and migration of PDGF-BB-treated A10 cells were abolished by compound C (an AMPK-specific inhibitor, 103 nM). In rats with balloon-injured carotid arteries, TSPO expression was markedly upregulated in the carotid arteries. Administration of PK11195 (3 mg/kg every 3 days, ip), starting from the initial balloon injury and lasting for 2 weeks, greatly attenuated carotid neointima formation by suppressing balloon injury-induced phenotype switching of VSMCs (increased α-SMA expression). These results suggest that TSPO is a vascular injury-response molecule that promotes VSMC proliferation and migration and is responsible for the neointima formation after vascular injury, which provides a novel therapeutic target for various cardiovascular diseases including atherosclerosis and restenosis.
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Tyler RE, Kim SW, Guo M, Jang YJ, Damadzic R, Stodden T, Vendruscolo LF, Koob GF, Wang GJ, Wiers CE, Volkow ND. Detecting neuroinflammation in the brain following chronic alcohol exposure in rats: A comparison between in vivo and in vitro TSPO radioligand binding. Eur J Neurosci 2019; 50:1831-1842. [PMID: 30803059 PMCID: PMC10714130 DOI: 10.1111/ejn.14392] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/17/2019] [Accepted: 02/08/2019] [Indexed: 12/18/2022]
Abstract
Excessive alcohol consumption is associated with neuroinflammation, which likely contributes to alcohol-related pathology. However, positron emission tomography (PET) studies using radioligands for the 18-kDa translocator protein (TSPO), which is considered a biomarker of neuroinflammation, reported decreased binding in alcohol use disorder (AUD) participants compared to controls. In contrast, autoradiographic findings in alcohol exposed rats reported increases in TSPO radioligand binding. To assess if these discrepancies reflected differences between in vitro and in vivo methodologies, we compared in vitro autoradiography (using [3 H]PBR28 and [3 H]PK11195) with in vivo PET (using [11 C]PBR28) in male, Wistar rats exposed to chronic alcohol-vapor (dependent n = 10) and in rats exposed to air-vapor (nondependent n = 10). PET scans were obtained with [11 C]PBR28, after which rats were euthanized and the brains were harvested for autoradiography with [3 H]PBR28 and [3 H]PK11195 (n = 7 dependent and n = 7 nondependent), and binding quantified in hippocampus, thalamus, and parietal cortex. Autoradiography revealed significantly higher binding in alcohol-dependent rats for both radioligands in thalamus and hippocampus (trend level for [3 H]PBR28) compared to nondependent rats, and these group differences were stronger for [3 H]PK11195 than [3 H]PBR28. In contrast, PET measures obtained in the same rats showed no group difference in [11 C]PBR28 binding. Our in vitro data are consistent with neuroinflammation associated with chronic alcohol exposure. Failure to observe similar increases in [11 C]PBR28 binding in vivo suggests the possibility that a mechanism mediated by chronic alcohol exposure interferes with [11 C]PBR28 binding to TSPO in vivo. These data question the sensitivity of PBR28 PET as a methodology to assess neuroinflammation in AUD.
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Affiliation(s)
- Ryan E. Tyler
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Sung Won Kim
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Min Guo
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Yeon Joo Jang
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Ruslan Damadzic
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Tyler Stodden
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Leandro F. Vendruscolo
- National Institute on Drug Abuse, National Institutes of Health, NIH, Baltimore, Maryland
| | - George F. Koob
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
- National Institute on Drug Abuse, National Institutes of Health, NIH, Baltimore, Maryland
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Corinde E. Wiers
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, Maryland
- National Institute on Drug Abuse, National Institutes of Health, NIH, Baltimore, Maryland
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20
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Stadulytė A, Alcaide-Corral CJ, Walton T, Lucatelli C, Tavares AAS. Analysis of PK11195 concentrations in rodent whole blood and tissue samples by rapid and reproducible chromatographic method to support target-occupancy PET studies. J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1118-1119:33-39. [PMID: 31005772 PMCID: PMC6522057 DOI: 10.1016/j.jchromb.2019.04.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 04/05/2019] [Accepted: 04/11/2019] [Indexed: 12/24/2022]
Abstract
In Positron Emission Tomography (PET) research, it is important to assess not only pharmacokinetics of a radiotracer in vivo, but also of the drugs used in blocking/displacement PET studies. Typically, pharmacokinetic/pharmacodynamic (PK/PD) analyses of drugs used in rodent PET studies are based on population average pharmacokinetic profiles of the drugs due to limited blood volume withdrawal while simultaneously maintaining physiological homeostasis. This likely results in bias of PET data quantification, including unknown bias of target occupancy (TO) measurements. This study aimed to develop a High Performance Liquid Chromatography (HPLC) method for PK/PD quantification of drugs used in preclinical rodent PET research, specifically the translocator 18 kDa protein (TSPO) selective drug, PK11195, that used sub-millilitre blood volumes. The lowest detection limit for the proposed HPLC method ranged between 7.5 and 10 ng/mL depending on the method used to calculate the limit of detection, and the measured average relative standard deviation for intermediate precision was equal to 17.2%. Most importantly, we were able to demonstrate a significant difference between calculated PK11195 concentrations at 0.5, 1, 2, 3, 5, 15 and 30 min post-administration and individually measured whole blood levels (significance level range from p < 0.05 to p < 0.001; one-way ANOVA, Dunnet's post hoc test, p < 0.05). The HPLC method developed here uses sub-millilitre sample volumes to reproducibly assess PK/PD of PK11195 in rodent blood. This study highlights the importance of individually measured PK/PD drug concentrations when quantifying the TO from blocking/displacement rodent PET experiments.
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Affiliation(s)
- Agnė Stadulytė
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK.
| | - Carlos José Alcaide-Corral
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK
| | - Tashfeen Walton
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, UK
| | - Christophe Lucatelli
- Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, UK
| | - Adriana Alexandre S Tavares
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK; Edinburgh Preclinical Imaging (EPI), University of Edinburgh, UK
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Kübler D, Wächter T, Cabanel N, Su Z, Turkheimer FE, Dodel R, Brooks DJ, Oertel WH, Gerhard A. Widespread microglial activation in multiple system atrophy. Mov Disord 2019; 34:564-568. [PMID: 30726574 PMCID: PMC6659386 DOI: 10.1002/mds.27620] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 12/31/2018] [Accepted: 01/02/2019] [Indexed: 11/22/2022] Open
Abstract
Background The pattern and role of microglial activation in multiple system atrophy is largely unclear. The objective of this study was to use [11C](R)‐PK11195 PET to determine the extent and correlation of activated microglia with clinical parameters in MSA patients. Methods Fourteen patients with the parkinsonian phenotype of MSA (MSA‐P) with a mean disease duration of 2.9 years (range 2‐5 years) were examined with [11C](R)‐PK11195 PET and compared with 10 healthy controls. Results Patients with the parkinsonian phenotype of MSA showed a significant (P ≤ 0.01) mean increase in binding potentials compared with healthy controls in the caudate nucleus, putamen, pallidum, precentral gyrus, orbitofrontal cortex, presubgenual anterior cingulate cortex, and the superior parietal gyrus. No correlations between binding potentials and clinical parameters were found. Conclusions In early clinical stages of the parkinsonian phenotype of MSA, there is widespread microglial activation as a marker of neuroinflammatory changes without correlation to clinical parameters in our patient population. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Dorothee Kübler
- Movement Disorders Section, Department of Neurology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Tobias Wächter
- Hertie-Institute for Clinical Brain Research, Department of Neurodegenerative Diseases, Tübingen, Germany.,Department of Neurology, Rehabilitation Centre Bad Gögging, Passauer Wolf, Bad Gögging, Germany
| | - Nicole Cabanel
- Vitos Clinical Centre for Psychiatry and Psychotherapy, Giessen-Marburg, Germany
| | - Zhangjie Su
- Department of Neurosurgery, Salford Royal NHS Foundation Trust, Salford, UK
| | - Federico E Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Richard Dodel
- Chair of Geriatrics, University Hospital Essen, Center for Geriatric Medicine Haus Berge, Essen, Germany
| | - David J Brooks
- Department of Nuclear Medicine and PET-Centre, Institute of Clinical Medicine, Aarhus University, Aarhus C, Denmark.,Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK
| | - Wolfgang H Oertel
- Department of Neurology, Philipps-Universität Marburg, Marburg, Germany.,Institute for Neurogenomics, Helmholtz Center for Health and Environment, München, Germany
| | - Alexander Gerhard
- Departments of Nulcear Medicine and Geriatric Medicine, University Hospital Essen, Germany.,Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
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22
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Kang Y, Mozley PD, Verma A, Schlyer D, Henchcliffe C, Gauthier SA, Chiao PC, He B, Nikolopoulou A, Logan J, Sullivan JM, Pryor KO, Hesterman J, Kothari PJ, Vallabhajosula S. Noninvasive PK11195-PET Image Analysis Techniques Can Detect Abnormal Cerebral Microglial Activation in Parkinson's Disease. J Neuroimaging 2018; 28:496-505. [PMID: 29727504 PMCID: PMC6174975 DOI: 10.1111/jon.12519] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 04/15/2018] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Neuroinflammation has been implicated in the pathophysiology of Parkinson's disease (PD), which might be influenced by successful neuroprotective drugs. The uptake of [11 C](R)-PK11195 (PK) is often considered to be a proxy for neuroinflammation, and can be quantified using the Logan graphical method with an image-derived blood input function, or the Logan reference tissue model using automated reference region extraction. The purposes of this study were (1) to assess whether these noninvasive image analysis methods can discriminate between patients with PD and healthy volunteers (HVs), and (2) to establish the effect size that would be required to distinguish true drug-induced changes from system variance in longitudinal trials. METHODS The sample consisted of 20 participants with PD and 19 HVs. Two independent teams analyzed the data to compare the volume of distribution calculated using image-derived input functions (IDIFs), and binding potentials calculated using the Logan reference region model. RESULTS With all methods, the higher signal-to-background in patients resulted in lower variability and better repeatability than in controls. We were able to use noninvasive techniques showing significantly increased uptake of PK in multiple brain regions of participants with PD compared to HVs. CONCLUSION Although not necessarily reflecting absolute values, these noninvasive image analysis methods can discriminate between PD patients and HVs. We see a difference of 24% in the substantia nigra between PD and HV with a repeatability coefficient of 13%, showing that it will be possible to estimate responses in longitudinal, within subject trials of novel neuroprotective drugs.
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Affiliation(s)
| | | | | | - David Schlyer
- Weill Cornell MedicineNew YorkNY
- Brookhaven National LaboratoriesNY
| | | | | | | | - Bin He
- Weill Cornell MedicineNew YorkNY
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23
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Jazvinšćak Jembrek M, Radovanović V, Vlainić J, Vuković L, Hanžić N. Neuroprotective effect of zolpidem against glutamate-induced toxicity is mediated via the PI3K/Akt pathway and inhibited by PK11195. Toxicology 2018; 406-407:58-69. [PMID: 29859204 DOI: 10.1016/j.tox.2018.05.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/27/2018] [Accepted: 05/29/2018] [Indexed: 11/30/2022]
Abstract
Excitotoxicity is a pathological process in which neuronal dysfunction and death are induced by excessive glutamate stimulation, the major fast excitatory neurotransmitter in the mammalian brain. Excitotoxicity-induced neurodegeneration is a contributing factor in ischemia-induced brain damage, traumatic brain injury, and various neurodegenerative diseases. It is triggered by calcium overload due to prolonged over-activation of ionotropic N-methyl-d-aspartate (NMDA) receptors. Enhanced Ca2+ release results in neuronal vulnerability through several intertwined mechanisms, including activation of proteolytic enzymes, increased production of reactive oxygen species (ROS), mitochondrial dysfunction and modulation of intracellular signalling pathways. We investigated the neuroprotective effect of hypnotic zolpidem, a drug that exerts its central effects at the GABAA receptor complex, against glutamate-induced toxicity in P19 neurons. Zolpidem prevented death of P19 neurons exposed to glutamate, and abolished the glutamate-induced increase in ROS production, p53 and Bax expression, and caspase-3/7 activity. Zolpidem effects were mediated by marked over-activation of Akt kinase. The pro-survival effect, as well as the pAkt induction, were prevented in the presence of wortmannin, an inhibitor of phosphatidylinositol-3-kinase (PI3K) that functions upstream of Akt. The beneficial effect of zolpidem on neuronal survival was not prevented by flumazenil, a GABAA receptor antagonist. PK11195, a drug that modulates the mitochondrial translocator protein 18 kDa (TSPO) and F0F1-ATPase, prevented the beneficial effect of zolpidem, indicating that the mechanism of zolpidem action involves preservation of mitochondrial function and integrity. Zolpidem effects were further mediated by prevention of glutamate-induced increase in the expression of the NR2B subunit of NMDA receptor. The obtained results suggest the promising therapeutic potential of zolpidem against excitotoxic insults and highlight the importance of mitochondria and the Akt pathway as valuable targets for therapeutic interventions in glutamate-mediated neuropathological conditions.
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Affiliation(s)
- Maja Jazvinšćak Jembrek
- Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenička cesta 54, Zagreb, Croatia; Department of Psychology, Catholic University of Croatia, Ilica 242, Zagreb, Croatia.
| | - Vedrana Radovanović
- Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenička cesta 54, Zagreb, Croatia
| | - Josipa Vlainić
- Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenička cesta 54, Zagreb, Croatia
| | - Lidija Vuković
- Division of Molecular Biology, Rudjer Boskovic Institute, Bijenička cesta 54, Zagreb, Croatia
| | - Nikolina Hanžić
- Division of Molecular Medicine, Rudjer Boskovic Institute, Bijenička cesta 54, Zagreb, Croatia
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24
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Filiou MD, Banati RB, Graeber MB. The 18-kDa Translocator Protein as a CNS Drug Target: Finding Our Way Through the Neuroinflammation Fog. CNS Neurol Disord Drug Targets 2017; 16:990-999. [PMID: 28982340 DOI: 10.2174/1871527316666171004125107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 09/19/2017] [Accepted: 09/28/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND & OBJECTIVE The 18-kDa translocator protein (TSPO) is located in the outer mitochondrial membrane where it is thought to co-regulate steroidogenesis, cellular bioenergetics as well as several other cellular processes. Originally discovered as a binding site for diazepam outside the CNS, notably in steroidogenic tissue and mononuclear phagocytes, the TSPO's historical designation was peripheral benzodiazepine receptor. Much of the recent interest in TSPO is due to the observation that its regulation in the brain is associated with microglial activation. Importantly, this activation can be visualized in vivo by positron emission tomography (PET) using TSPO ligands. TSPO levels in normal brain tissue are close to current detection limits, being restricted to blood vessels and possibly areas of natural cell turnover. However, any progressive tissue damage is associated with a marked increase in TSPO expression, most prominently in activated microglia. Therefore, the inducible TSPO expression can serve as an exquisitely responsive sensor in a range of active brain pathologies, which are often conflated under the term 'neuroinflammation'. However, what occurs histologically in 'neuroinflammation' is different from classical brain tissue inflammation in the vast majority of cases. The resulting conceptual confusion poses potentially significant risks for patients who receive misguided anti-inflammatory treatment. It also obscures the fact that microglia may have other important roles, notably at synapses. 'Neuroinflammation' is at the current level of our understanding primarily the observation of dynamic tissue changes in the brain, the relevance of which for disease progression or brain plasticity phenomena is likely to be context dependent and remains to be worked out in detail. Here, we discuss the potential of TSPO as a therapeutic drug target for CNS disorders. CONCLUSION In this review, we focus on psychiatric and neurodegenerative disorders, elaborate the role of TSPO and the effects of TSPO ligands on common disease phenotypes reviewing evidence from both animal models and patient cohorts and discuss future directions. As a modulator of pivotal cell processes, TSPO may serve as a drug target in well defined translational applications.
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Affiliation(s)
- Michaela D Filiou
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Richard B Banati
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia.,Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia.,Medical Imaging & Radiation Sciences, Faculty of Health Science and Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales 2006, Australia.,National Imaging Facility, Sydney, Camperdown, New South Wales 2006, Australia
| | - Manuel B Graeber
- Brain Tumor Research Laboratories, Brain and Mind Center, Sydney Medical School and Faculty of Health Sciences, Camperdown, NSW 2050, Australia.,Discipline of Anatomy and Embryology, School of Medical Sciences, Sydney Medical School, Australia.,Charles Perkins Center, Sydney, Australia.,Bosch Institute, The University of Sydney, Sydney, Australia
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25
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Wu Y, Shamoto-Nagai M, Maruyama W, Osawa T, Naoi M. Phytochemicals prevent mitochondrial membrane permeabilization and protect SH-SY5Y cells against apoptosis induced by PK11195, a ligand for outer membrane translocator protein. J Neural Transm (Vienna) 2016; 124:89-98. [PMID: 27640013 DOI: 10.1007/s00702-016-1624-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/09/2016] [Indexed: 02/07/2023]
Abstract
Epidemiological studies present the beneficial effects of dietary habits on prevention of aging-associated decline of brain function. Phytochemicals, the second metabolites of food, protect neuronal cells from cell death in cellular models of neurodegenerative disorders, and the neuroprotective activity has been ascribed to the anti-oxidant and anti-inflammatory functions. In this paper, the cellular mechanism of neuroprotection by phytochemicals was investigated, using the cellular model of mitochondrial apoptosis induced by PK11195, a ligand of outer membrane translocator protein, in SH-SY5Y cells. PK11195 induced mitochondrial membrane permeabilization with rapid transit production of superoxide (superoxide flashes) and calcium release from mitochondria, and activated apoptosis signal pathway. Study on the structure-activity relationship of astaxanthin, ferulic acid derivatives, and sesame lignans revealed that these phytochemicals inhibited mitochondrial membrane permeabilization and protected cells from apoptosis. Ferulic acid derivatives and sesame lignans inhibited or enhanced the mitochondrial pore formation and cell death by PK11195 according to their amphiphilic properties, not directly depending on the antioxidant activity. Regulation of pore formation at mitochondrial membrane is discussed as a novel mechanism behind neuroprotective activity of phytochemicals in aging and age-associated neurodegenerative disorders, and also behind dual functions of phytochemicals in neuronal and cancer cells.
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Affiliation(s)
- Yuqiu Wu
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 320-0195, Japan
| | - Masayo Shamoto-Nagai
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 320-0195, Japan
| | - Wakako Maruyama
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 320-0195, Japan
| | - Toshihiko Osawa
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 320-0195, Japan
| | - Makoto Naoi
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 320-0195, Japan.
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26
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Azarashvili T, Krestinina O, Baburina Y, Odinokova I, Grachev D, Papadopoulos V, Akatov V, Lemasters JJ, Reiser G. Combined effect of G3139 and TSPO ligands on Ca(2+)-induced permeability transition in rat brain mitochondria. Arch Biochem Biophys 2015; 587:70-7. [PMID: 26498031 DOI: 10.1016/j.abb.2015.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
Abstract
Permeability of the mitochondrial outer membrane is determined by the activity of voltage-dependent anion channels (VDAC) which are regulated by many factors and proteins. One of the main partner-regulator of VDAC is the 18 kDa translocator protein (TSPO), whose role in the regulation of membrane permeability is not completely understood. We show that TSPO ligands, 1 μM PPIX and PK11195 at concentrations of 50 μM, accelerate opening of permeability transition pores (mPTP) in Ca(2+)-overloaded rat brain mitochondria (RBM). By contrast, PK11195 at 100 nM and anti-TSPO antibodies suppressed pore opening. Participation of VDAC in these processes was demonstrated by blocking VDAC with G3139, an 18-mer phosphorothioate oligonucleotides, which sensitized mitochondria to Ca(2+)-induced mPTP opening. Despite the inhibitory effect of 100 nM PK11195 and anti-TSPO antibodies alone, their combination with G3139 considerably stimulated the mPTP opening. Thus, 100 nM PK11195 and anti-TSPO antibody can modify permeability of the VDAC channel and mPTP. When VDAC channels are closed and TSPO is blocked, permeability of the VDAC for calcium seems to be the highest, which leads to accelerated pore opening.
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Affiliation(s)
- T Azarashvili
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - O Krestinina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - Yu Baburina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - I Odinokova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - D Grachev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - V Papadopoulos
- The Research Institute of the McGill University Health Center, and Departments of Medicine, Biochemistry, Pharmacology and Therapeutics, McGill University, 2155 Guy Street, Montreal, Que., H3H 2R9, Canada.
| | - V Akatov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - J J Lemasters
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia; Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology, Medical University of South Carolina, DD504 Drug Discovery Bldg., 70 President St., MSC 140, Charleston, SC, 29425, USA.
| | - G Reiser
- Institut für Neurobiochemie, Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany.
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27
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Turkheimer FE, Rizzo G, Bloomfield PS, Howes O, Zanotti-Fregonara P, Bertoldo A, Veronese M. The methodology of TSPO imaging with positron emission tomography. Biochem Soc Trans 2015; 43:586-92. [PMID: 26551697 DOI: 10.1042/BST20150058] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Indexed: 11/17/2022]
Abstract
The 18-kDA translocator protein (TSPO) is consistently elevated in activated microglia of the central nervous system (CNS) in response to a variety of insults as well as neurodegenerative and psychiatric conditions. It is therefore a target of interest for molecular strategies aimed at imaging neuroinflammation in vivo. For more than 20 years, positron emission tomography (PET) has allowed the imaging of TSPO density in brain using [11C]-(R)-PK11195, a radiolabelled-specific antagonist of the TSPO that has demonstrated microglial activation in a large number pathological cohorts. The significant clinical interest in brain immunity as a primary or comorbid factor in illness has sparked great interest in the TSPO as a biomarker and a surprising number of second generation TSPO radiotracers have been developed aimed at improving the quality of TSPO imaging through novel radioligands with higher affinity. However, such major investment has not yet resulted in the expected improvement in image quality. We here review the main methodological aspects of TSPO PET imaging with particular attention to TSPO genetics, cellular heterogeneity of TSPO in brain tissue and TSPO distribution in blood and plasma that need to be considered in the quantification of PET data to avoid spurious results as well as ineffective development and use of these radiotracers.
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Hatty CR, Banati RB. Protein-ligand and membrane-ligand interactions in pharmacology: the case of the translocator protein (TSPO). Pharmacol Res 2015; 100:58-63. [PMID: 26238176 DOI: 10.1016/j.phrs.2015.07.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 11/30/2022]
Abstract
The targets of many small molecule drugs are membrane proteins, and traditionally the focus of pharmacology is on the interaction between such receptors and their small molecule drug ligands. However, the lipid membranes of cells and organelles are increasingly appreciated as diverse and dynamic structures that also specifically interact with small molecule drugs and peptides, causing profound changes in the properties of these membranes, and modulating the function of the membrane and the proteins within it. Drug-membrane interactions are likely to have a role in both the therapeutic and toxic activity of a variety of compounds, and their role in the overall pharmacological effect of a drug needs to be understood more clearly. This is the case for the 18 kDa translocator protein (TSPO) and its ligands, where functions that were established based on pharmacological studies are being called into question. Re-examining the putative functions of the TSPO and the effects of its ligands reveals a need to consider in more detail the interplay between protein-ligand and membrane-ligand interactions, and the modulatory relationship between TSPO and the lipid membrane.
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Affiliation(s)
- Claire R Hatty
- Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, The University of Sydney, Brain & Mind Research Institute, 94 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Richard B Banati
- Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, The University of Sydney, Brain & Mind Research Institute, 94 Mallett Street, Camperdown, NSW 2050, Australia; Life Sciences, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
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Liu G, Middleton RJ, Hatty CR, Kam WW, Chan R, Pham T, Harrison‐Brown M, Dodson E, Veale K, Banati RB. The 18 kDa translocator protein, microglia and neuroinflammation. Brain Pathol 2014; 24:631-53. [PMID: 25345894 PMCID: PMC8029074 DOI: 10.1111/bpa.12196] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 08/19/2014] [Indexed: 12/17/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is expressed in the injured brain. It has become known as an imaging marker of "neuroinflammation" indicating active disease, and is best interpreted as a nondiagnostic biomarker and disease staging tool that refers to histopathology rather than disease etiology. The therapeutic potential of TSPO as a drug target is mostly based on the understanding that it is an outer mitochondrial membrane protein required for the translocation of cholesterol, which thus regulates the rate of steroid synthesis. This pivotal role together with the evolutionary conservation of TSPO has underpinned the belief that any loss or mutation of TSPO should be associated with significant physiological deficits or be outright incompatible with life. However, against prediction, full Tspo knockout mice are viable and across their lifespan do not show the phenotype expected if cholesterol transport and steroid synthesis were significantly impaired. Thus, the "translocation" function of TSPO remains to be better substantiated. Here, we discuss the literature before and after the introduction of the new nomenclature for TSPO and review some of the newer findings. In light of the controversy surrounding the function of TSPO, we emphasize the continued importance of identifying compounds with confirmed selectivity and suggest that TSPO expression is analyzed within specific disease contexts rather than merely equated with the reified concept of "neuroinflammation."
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Affiliation(s)
- Guo‐Jun Liu
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Ryan J. Middleton
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Claire R. Hatty
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Winnie Wai‐Ying Kam
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Ronald Chan
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Tien Pham
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Meredith Harrison‐Brown
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Eoin Dodson
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
| | - Kelly Veale
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
| | - Richard B. Banati
- Life SciencesAustralian Nuclear Science and Technology OrganisationNSWAustralia
- Brain & Mind Research InstituteThe University of SydneyNSWAustralia
- Discipline of Medical Imaging & Radiation SciencesFaculty of Health SciencesThe University of SydneyNSWAustralia
- National Imaging Facility and Ramaciotti Brain Imaging CentreSydneyNSWAustralia
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Shivers KY, Nikolopoulou A, Machlovi SI, Vallabhajosula S, Figueiredo-Pereira ME. PACAP27 prevents Parkinson-like neuronal loss and motor deficits but not microglia activation induced by prostaglandin J2. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1707-19. [PMID: 24970746 DOI: 10.1016/j.bbadis.2014.06.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 06/11/2014] [Accepted: 06/17/2014] [Indexed: 12/16/2022]
Abstract
Neuroinflammation is a major risk factor in Parkinson's disease (PD). Alternative approaches are needed to treat inflammation, as anti-inflammatory drugs such as NSAIDs that inhibit cyclooxygenase-2 (COX-2) can produce devastating side effects, including heart attack and stroke. New therapeutic strategies that target factors downstream of COX-2, such as prostaglandin J2 (PGJ2), hold tremendous promise because they will not alter the homeostatic balance offered by COX-2 derived prostanoids. In the current studies, we report that repeated microinfusion of PGJ2 into the substantia nigra of non-transgenic mice, induces three stages of pathology that mimic the slow-onset cellular and behavioral pathology of PD: mild (one injection) when only motor deficits are detectable, intermediate (two injections) when neuronal and motor deficits as well as microglia activation are detectable, and severe (four injections) when dopaminergic neuronal loss is massive accompanied by microglia activation and motor deficits. Microglia activation was evaluated in vivo by positron emission tomography (PET) with [(11)C](R)PK11195 to provide a regional estimation of brain inflammation. PACAP27 reduced dopaminergic neuronal loss and motor deficits induced by PGJ2, without preventing microglia activation. The latter could be problematic in that persistent microglia activation can exert long-term deleterious effects on neurons and behavior. In conclusion, this PGJ2-induced mouse model that mimics in part chronic inflammation, exhibits slow-onset PD-like pathology and is optimal for testing diagnostic tools such as PET, as well as therapies designed to target the integrated signaling across neurons and microglia, to fully benefit patients with PD.
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Affiliation(s)
- Kai-Yvonne Shivers
- Department of Biological Sciences, Hunter College, Graduate School and University Center, CUNY, New York, NY 10065, USA
| | - Anastasia Nikolopoulou
- Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA
| | - Saima Ishaq Machlovi
- Department of Biological Sciences, Hunter College, Graduate School and University Center, CUNY, New York, NY 10065, USA
| | - Shankar Vallabhajosula
- Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA
| | - Maria E Figueiredo-Pereira
- Department of Biological Sciences, Hunter College, Graduate School and University Center, CUNY, New York, NY 10065, USA.
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Walberer M, Jantzen SU, Backes H, Rueger MA, Keuters MH, Neumaier B, Hoehn M, Fink GR, Graf R, Schroeter M. In-vivo detection of inflammation and neurodegeneration in the chronic phase after permanent embolic stroke in rats. Brain Res 2014; 1581:80-8. [PMID: 24905627 DOI: 10.1016/j.brainres.2014.05.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/07/2014] [Accepted: 05/21/2014] [Indexed: 11/25/2022]
Abstract
Neuroinflammation with microglia activation (MA) constitutes a key tissue response in acute stroke. Until now, its course in the chronic stage is less well defined. Here, we investigated (i) neuroinflammation in the chronic stage of a rat model of embolic stroke (n=6), and (ii) whether this process can be visualized in vivo by multimodal imaging using Magnetic Resonance Imaging (MRI) and Positron-Emission-Tomography (PET). Imaging data were verified using histology and immunohistochemistry. Repetitive PET studies until week 6 after stroke reveal poststroke inflammation as a dynamic process that involved the infarct, the surrounding tissue and secondary degenerating areas in a complex fashion. At the end, 7 months after stroke, neuroinflammation had almost completely vanished at the lesion side. In contrast, remote from the primarily infarcted areas, a marked T2(*)- hypointensity was detected in the ipsilateral thalamus. In the corresponding area, [(11)C]PK11195-PET detected microglia activation. Immunohistochemistry confirmed activated microglia in the ipsilateral thalamus with signs of extensive phagocytosis and iron deposition around plaque-like amyloid deposition. Neuronal staining (NeuN) revealed pronounced neuronal loss as an endpoint of neurodegeneration in these areas. In conclusion, the data demonstrate not only ongoing thalamic neuroinflammation but also marked neurodegeneration remote from the lesion site in the chronic phase after stroke in rats. Both, neuroinflammation and neurodegeneration were accessible to (immuno-) histochemical methods as well as to in vivo methods using [(11)C]PK11195-PET and T2(*)-weighted MRI. Although the functional roles of these dynamic processes remain to be elucidated, ongoing destruction of neuronal tissue is conceivable. Its inhibition using anti-inflammatory substances may be beneficial in chronic post-stroke conditions, while multimodal imaging can be used to evaluate putative therapeutic effects in vivo.
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Affiliation(s)
- Maureen Walberer
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Sabine U Jantzen
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Heiko Backes
- Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Maria A Rueger
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Meike H Keuters
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Bernd Neumaier
- Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Mathias Hoehn
- Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Gereon R Fink
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Institute of Neuroscience and Medicine (INM-3), Cognitive Neuroscience, Research Centre Juelich, 52425 Juelich, Germany
| | - Rudolf Graf
- Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany
| | - Michael Schroeter
- Department of Neurology, University Hospital, Kerpener Str. 62, 50924 Cologne, Germany; Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany.
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Hatty CR, Le Brun AP, Lake V, Clifton LA, Liu GJ, James M, Banati RB. Investigating the interactions of the 18kDa translocator protein and its ligand PK11195 in planar lipid bilayers. Biochim Biophys Acta 2013; 1838:1019-30. [PMID: 24374318 DOI: 10.1016/j.bbamem.2013.12.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/16/2013] [Accepted: 12/18/2013] [Indexed: 12/20/2022]
Abstract
The functional effects of a drug ligand may be due not only to an interaction with its membrane protein target, but also with the surrounding lipid membrane. We have investigated the interaction of a drug ligand, PK11195, with its primary protein target, the integral membrane 18kDa translocator protein (TSPO), and model membranes using Langmuir monolayers, quartz crystal microbalance with dissipation monitoring (QCM-D) and neutron reflectometry (NR). We found that PK11195 is incorporated into lipid monolayers and lipid bilayers, causing a decrease in lipid area/molecule and an increase in lipid bilayer rigidity. NR revealed that PK11195 is incorporated into the lipid chain region at a volume fraction of ~10%. We reconstituted isolated mouse TSPO into a lipid bilayer and studied its interaction with PK11195 using QCM-D, which revealed a larger than expected frequency response and indicated a possible conformational change of the protein. NR measurements revealed a TSPO surface coverage of 23% when immobilised to a modified surface via its polyhistidine tag, and a thickness of 51Å for the TSPO layer. These techniques allowed us to probe both the interaction of TSPO with PK11195, and PK11195 with model membranes. It is possible that previously reported TSPO-independent effects of PK11195 are due to incorporation into the lipid bilayer and alteration of its physical properties. There are also implications for the variable binding profiles observed for TSPO ligands, as drug-membrane interactions may contribute to the apparent affinity of TSPO ligands.
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Affiliation(s)
- Claire R Hatty
- Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, The University of Sydney, c/o Brain & Mind Research Institute, 94 Mallett Street, Camperdown, NSW 2050, Australia
| | - Anton P Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Vanessa Lake
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
| | - Guo Jun Liu
- Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, The University of Sydney, c/o Brain & Mind Research Institute, 94 Mallett Street, Camperdown, NSW 2050, Australia; Life Sciences, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Michael James
- Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia; School of Chemistry, University of New South Wales, Kensington NSW 2052, Australia
| | - Richard B Banati
- Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, The University of Sydney, c/o Brain & Mind Research Institute, 94 Mallett Street, Camperdown, NSW 2050, Australia; Life Sciences, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
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33
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Green ML, Pisano MM, Prough RA, Knudsen TB. Release of targeted p53 from the mitochondrion as an early signal during mitochondrial dysfunction. Cell Signal 2013; 25:2383-90. [PMID: 23899557 PMCID: PMC3826263 DOI: 10.1016/j.cellsig.2013.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/08/2013] [Accepted: 07/19/2013] [Indexed: 01/28/2023]
Abstract
Increased accumulation of p53 tumor suppressor protein is an early response to low-level stressors. To investigate the fate of mitochondrial-sequestered p53, mouse embryonic fibroblast cells (MEFs) on a p53-deficient genetic background were transfected with p53-EGFP fusion protein led by a sense (m53-EGFP) or antisense (c53-EGFP) mitochondrial import signal. Rotenone exposure (100nM, 1h) triggered the translocation of m53-EGFP from the mitochondrion to the nucleus, thus shifting the transfected cells from a mitochondrial p53 to a nuclear p53 state. Antibodies for p53 serine phosphorylation or lysine acetylation indicated a different post-translational status of recombinant p53 in the nucleus and mitochondrion, respectively. These data suggest that cycling of p53 through the mitochondria may establish a direct pathway for p53 signaling from the mitochondria to the nucleus during mitochondrial dysfunction. PK11195, a pharmacological ligand of mitochondrial TSPO (formerly known as the peripheral-type benzodiazepine receptor), partially suppressed the release of mitochondria-sequestered p53. These findings support the notion that p53 function mediates a direct signaling pathway from the mitochondria to nucleus during mitochondrial dysfunction.
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Affiliation(s)
- M L Green
- Department of Molecular, Cellular and Craniofacial Biology, University of Louisville, 501 S. Preston St., Louisville, KY 40202, USA; Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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Qiu ZK, Zhang LM, Zhao N, Chen HX, Zhang YZ, Liu YQ, Mi TY, Zhou WW, Li Y, Yang RF, Xu JP, Li YF. Repeated administration of AC-5216, a ligand for the 18 kDa translocator protein, improves behavioral deficits in a mouse model of post-traumatic stress disorder. Prog Neuropsychopharmacol Biol Psychiatry 2013; 45:40-6. [PMID: 23624119 DOI: 10.1016/j.pnpbp.2013.04.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 11/17/2022]
Abstract
Post-traumatic stress disorder (PTSD) is a severely disabling anxiety disorder that may occur following exposure to a serious traumatic event. It is a psychiatric condition that can afflict anyone who has experienced a life-threatening or violent event. Previous studies have shown that changes in 18 kDa translocator protein (TSPO) expression (or function), a promising target for treating neurological disorders without benzodiazepine-like side effects, may correlate with PTSD. However, few studies have investigated the anti-PTSD effects of TSPO ligands. AC-5216, a ligand for TSPO, induces anxiolytic- and anti-depressant-like effects in animal models. The present study aimed to determine whether AC-5216 ameliorates PTSD behavior in mice. Following the training session consisting of exposure to inescapable electric foot shocks, animals were administered AC-5216 daily during the behavioral assessments, i.e., situational reminders (SRs), the open field (OF) test, the elevated plus-maze (EPM) test, and the staircase test (ST). The results indicated that exposure to foot shocks induced long-term behavioral deficiencies in the mice, including freezing and anxiety-like behavior, which were significantly ameliorated by repeated treatment with AC-5216 but without any effect on spontaneous locomotor activity or body weight. In summary, this study demonstrated the anti-PTSD effects of AC-5216 treatment, suggesting that TSPO may represent a therapeutic target for anti-PTSD drug discovery and that TSPO ligands may be a promising new class of drugs for the future treatment of PTSD.
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Affiliation(s)
- Zhi-Kun Qiu
- Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China
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Ammirati E, Magnoni M, Camici PG. Need for new non-invasive imaging strategies to identify high-risk asymptomatic patients with carotid stenosis. Int J Cardiol 2013; 168:4342-3. [PMID: 23727106 DOI: 10.1016/j.ijcard.2013.05.079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 05/04/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Enrico Ammirati
- San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
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Mendonça-Torres MC, Roberts SS. The translocator protein (TSPO) ligand PK11195 induces apoptosis and cell cycle arrest and sensitizes to chemotherapy treatment in pre- and post-relapse neuroblastoma cell lines. Cancer Biol Ther 2013; 14:319-26. [PMID: 23358477 DOI: 10.4161/cbt.23613] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
High-risk neuroblastoma (NB) has a poor prognosis. Even with intensive myeloablative chemotherapy, relapse is common and almost uniformly fatal, and new treatments are needed. Translocator protein 18kDa (TSPO) ligands have been studied as potential new therapeutic agents in many cancers, but not in NB. We studied the effects of TSPO ligands on cell proliferation, cell cycle progression and apoptosis using paired cell lines derived from the same patient at the time of initial surgery and again after development of progressive disease or relapse post-chemotherapy. We found that TSPO expression was significantly increased 2- to 10-fold in post-relapse cell lines compared with pre-treatment lines derived from the same individual. Subsequently, these cell lines were treated with the specific TSPO ligand 1-(2-chlorophenyl-N-methylpropyl)-3-isoquinolinecarboxamide (PK11195) (0-160µM) as a single agent, with cytotoxic chemotherapy agents alone (carboplatin, etoposide or melphalan), or with combinations of PK11195 and chemotherapy drugs. We found that PK11195 inhibited proliferation in a dose-dependent manner, induced apoptosis and caused G 1/S cell cycle arrest in all tested NB cell lines at micromolar concentrations. In addition, PK11195 significantly decreased mRNA expression of the chemotherapy resistance efflux pumps ABCA3, ABCB1 and ABCC1 in two post-relapse NB cell lines. We also found that pre-treatment with PK11195 sensitized these cell lines to treatment with cytotoxic chemotherapy agents. These results suggest that PK11195 alone or in combination with standard chemotherapeutic drugs warrants further study for the treatment of neuroblastoma.
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Affiliation(s)
- Maria C Mendonça-Torres
- Department of Pediatrics, Division of Hematology/Oncology, Uniformed Services University of the Health Sciences, Bethesda, MD USA
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Abstract
Microglia constitute the main immune defense in the central nervous system. In response to neuronal injury, microglia become activated, acquire phagocytic properties, and release a wide range of pro-inflammatory mediators that are essential for the annihilation of the neuronal insult. Although the role of microglial activation in acute neuronal damage is well defined, the pathophysiological processes underlying destructive or protective role to neurons following chronic exposure to microglial activation is still a subject of debate. It is likely that chronic exposure induces detrimental effects by promoting neuronal death through the release of neurotoxic factors. Positron emission tomography (PET) imaging with the use of translocator protein (TSPO) radioligands provides an in vivo tool for tracking the progression and severity of neuroinflammation in neurodegenerative disease. TSPO expression is correlated to the extent of microglial activation and the measurement of TSPO uptake in vivo with PET is a useful indicator of active disease. Although understanding of the interaction between radioligands and TSPO is not completely clear, there is a wide interest in application of TSPO imaging in neurodegenerative disease. In this article, we aim to review the applications of in vivo microglia imaging in neurodegenerative disorders such as Parkinson's disease, Huntington's disease, Dementias, and Multiple Sclerosis.
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Affiliation(s)
- Marios Politis
- Division of Experimental Medicine, Faculty of Medicine, Centre for Neuroscience, Hammersmith Hospital, Imperial College London London, UK
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