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Gold L, Barci E, Brendel M, Orth M, Cheng J, Kirchleitner SV, Bartos LM, Pötter D, Kirchner MA, Unterrainer LM, Kaiser L, Ziegler S, Weidner L, Riemenschneider MJ, Unterrainer M, Belka C, Tonn JC, Bartenstein P, Niyazi M, von Baumgarten L, Kälin RE, Glass R, Lauber K, Albert NL, Holzgreve A. The Traumatic Inoculation Process Affects TSPO Radioligand Uptake in Experimental Orthotopic Glioblastoma. Biomedicines 2024; 12:188. [PMID: 38255293 PMCID: PMC10813339 DOI: 10.3390/biomedicines12010188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
BACKGROUND The translocator protein (TSPO) has been proven to have great potential as a target for the positron emission tomography (PET) imaging of glioblastoma. However, there is an ongoing debate about the potential various sources of the TSPO PET signal. This work investigates the impact of the inoculation-driven immune response on the PET signal in experimental orthotopic glioblastoma. METHODS Serial [18F]GE-180 and O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) PET scans were performed at day 7/8 and day 14/15 after the inoculation of GL261 mouse glioblastoma cells (n = 24) or saline (sham, n = 6) into the right striatum of immunocompetent C57BL/6 mice. An additional n = 25 sham mice underwent [18F]GE-180 PET and/or autoradiography (ARG) at days 7, 14, 21, 28, 35, 50 and 90 in order to monitor potential reactive processes that were solely related to the inoculation procedure. In vivo imaging results were directly compared to tissue-based analyses including ARG and immunohistochemistry. RESULTS We found that the inoculation process represents an immunogenic event, which significantly contributes to TSPO radioligand uptake. [18F]GE-180 uptake in GL261-bearing mice surpassed [18F]FET uptake both in the extent and the intensity, e.g., mean target-to-background ratio (TBRmean) in PET at day 7/8: 1.22 for [18F]GE-180 vs. 1.04 for [18F]FET, p < 0.001. Sham mice showed increased [18F]GE-180 uptake at the inoculation channel, which, however, continuously decreased over time (e.g., TBRmean in PET: 1.20 at day 7 vs. 1.09 at day 35, p = 0.04). At the inoculation channel, the percentage of TSPO/IBA1 co-staining decreased, whereas TSPO/GFAP (glial fibrillary acidic protein) co-staining increased over time (p < 0.001). CONCLUSION We identify the inoculation-driven immune response to be a relevant contributor to the PET signal and add a new aspect to consider for planning PET imaging studies in orthotopic glioblastoma models.
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Affiliation(s)
- Lukas Gold
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Enio Barci
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Munich Cluster for Systems Neurology (SyNergy), LMU Munich, 81377 Munich, Germany
| | - Michael Orth
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Jiying Cheng
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Sabrina V. Kirchleitner
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
| | - Laura M. Bartos
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Dennis Pötter
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Maximilian A. Kirchner
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lena M. Unterrainer
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lena Kaiser
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Sibylle Ziegler
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
| | - Lorraine Weidner
- Department of Neuropathology, Regensburg University Hospital, 93053 Regensburg, Germany
| | | | - Marcus Unterrainer
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- DIE RADIOLOGIE, 80331 Munich, Germany
| | - Claus Belka
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Joerg-Christian Tonn
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- Munich Cluster for Systems Neurology (SyNergy), LMU Munich, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Maximilian Niyazi
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- Department of Radiation Oncology, University Hospital Tübingen, 72076 Tübingen, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Louisa von Baumgarten
- Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Roland E. Kälin
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Rainer Glass
- Neurosurgical Research, Department of Neurosurgery, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
| | - Kirsten Lauber
- Department of Radiation Oncology, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
| | - Nathalie L. Albert
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
- German Cancer Consortium (DKTK), Partner Site Munich, 81377 Munich, Germany
- Bavarian Cancer Research Center (BZKF), 81377 Munich, Germany
| | - Adrien Holzgreve
- Department of Nuclear Medicine, LMU University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany; (L.G.)
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2
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Kessler W, Thomas C, Kuhlmann T. Microglia activation in periplaque white matter in multiple sclerosis depends on age and lesion type, but does not correlate with oligodendroglial loss. Acta Neuropathol 2023; 146:817-828. [PMID: 37897549 PMCID: PMC10628007 DOI: 10.1007/s00401-023-02645-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/30/2023]
Abstract
Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the CNS. The disease course in MS is highly variable and driven by a combination of relapse-driven disease activity and relapse-independent disease progression. The formation of new focal demyelinating lesions is associated with clinical relapses; however, the pathological mechanisms driving disease progression are less well understood. Current concepts suggest that ongoing focal and diffuse inflammation within the CNS in combination with an age-associated failure of compensatory and repair mechanisms contribute to disease progression. The aim of our study was to characterize the diffuse microglia activation in periplaque white matter (PPWM) of MS patients, to identify factors modulating its extent and to determine its potential correlation with loss or preservation of oligodendrocytes. We analyzed microglial and oligodendroglial numbers in PPWM in a cohort of 96 tissue blocks from 32 MS patients containing 100 lesions as well as a control cohort (n = 37). Microglia activation in PPWM was dependent on patient age, proximity to lesion, lesion type, and to a lesser degree on sex. Oligodendrocyte numbers were decreased in PPWM; however, increased microglia densities did not correlate with lower oligodendroglial cell counts, indicating that diffuse microglia activation is not sufficient to drive oligodendroglial loss in PPWM. In summary, our findings support the notion of the close relationship between focal and diffuse inflammation in MS and that age is an important modulator of MS pathology.
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Affiliation(s)
- Wiebke Kessler
- Institute of Neuropathology, University Hospital Münster, Pottkamp 2, 48149, Münster, Germany
| | - Christian Thomas
- Institute of Neuropathology, University Hospital Münster, Pottkamp 2, 48149, Münster, Germany
| | - Tanja Kuhlmann
- Institute of Neuropathology, University Hospital Münster, Pottkamp 2, 48149, Münster, Germany.
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3
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Bedi SS, Scott MC, Skibber MA, Kumar A, Caplan HW, Xue H, Sequeira D, Speer AL, Cardenas F, Gudenkauf F, Uray K, Srivastava AK, Prossin AR, Cox CS. PET imaging of microglia using PBR28suv determines therapeutic efficacy of autologous bone marrow mononuclear cells therapy in traumatic brain injury. Sci Rep 2023; 13:16142. [PMID: 37752232 PMCID: PMC10522669 DOI: 10.1038/s41598-023-43245-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 09/21/2023] [Indexed: 09/28/2023] Open
Abstract
Traumatic brain injury (TBI) results in activated microglia. Activated microglia can be measured in vivo by using positron emission topography (PET) ligand peripheral benzodiazepine receptor standardized uptake values (PBR28suv). Cell based therapies have utilized autologous bone marrow mononuclear cells (BMMNCs) to attenuate activated microglia after TBI. This study aims to utilize in vivo PBR28suv to assess the efficacy of BMMNCs therapy after TBI. Seventy-two hours after CCI injury, BMMNCs were harvested from the tibia and injected via tail-vein at 74 h after injury at a concentration of 2 million cells per kilogram of body weight. There were three groups of rats: Sham, CCI-alone and CCI-BMMNCs (AUTO). One hundred twenty days after injury, rodents were imaged with PBR28 and their cognitive behavior assessed utilizing the Morris Water Maze. Subsequent ex vivo analysis included brain volume and immunohistochemistry. BMMNCs therapy attenuated PBR28suv in comparison to CCI alone and it improved spatial learning as measured by the Morris Water Maze. Ex vivo analysis demonstrated preservation of brain volume, a decrease in amoeboid-shaped microglia in the dentate gyrus and an increase in the ratio of ramified to amoeboid microglia in the thalamus. PBR28suv is a viable option to measure efficacy of BMMNCs therapy after TBI.
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Affiliation(s)
- Supinder S Bedi
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA.
| | - Michael C Scott
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Max A Skibber
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Akshita Kumar
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Henry W Caplan
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Hasen Xue
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - David Sequeira
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Alison L Speer
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Fanni Cardenas
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Franciska Gudenkauf
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Karen Uray
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
| | - Amit K Srivastava
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA
| | - Alan R Prossin
- Department of Psychiatry and Behavioral Sciences, University of Texas Medical School at Houston, Houston, TX, USA
| | - Charles S Cox
- Department of Pediatric Surgery, University of Texas Medical School at Houston, 6431 Fannin Street, MSB 5.230, Houston, TX, 77030, USA
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Raval NR, Angarita G, Matuskey D, Miller R, Drake LR, Kapinos M, Nabulsi N, Huang Y, Carson RE, O'Malley SS, Cosgrove KP, Hillmer AT. Imaging the brain's immune response to alcohol with [ 11C]PBR28 TSPO Positron Emission Tomography. Mol Psychiatry 2023; 28:3384-3390. [PMID: 37532797 PMCID: PMC10743097 DOI: 10.1038/s41380-023-02198-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/04/2023]
Abstract
In humans, the negative effects of alcohol are linked to immune dysfunction in both the periphery and the brain. Yet acute effects of alcohol on the neuroimmune system and its relationships with peripheral immune function are not fully understood. To address this gap, immune response to an alcohol challenge was measured with positron emission tomography (PET) using the radiotracer [11C]PBR28, which targets the 18-kDa translocator protein, a marker sensitive to immune challenges. Participants (n = 12; 5 F; 25-45 years) who reported consuming binge levels of alcohol (>3 drinks for females; >4 drinks for males) 1-3 months before scan day were enrolled. Imaging featured a baseline [11C]PBR28 scan followed by an oral laboratory alcohol challenge over 90 min. An hour later, a second [11C]PBR28 scan was acquired. Dynamic PET data were acquired for at least 90 min with arterial blood sampling to measure the metabolite-corrected input function. [11C]PBR28 volume of distributions (VT) was estimated in the brain using multilinear analysis 1. Subjective effects, blood alcohol levels (BAL), and plasma cytokines were measured during the paradigm. Full completion of the alcohol challenge and data acquisition occurred for n = 8 (2 F) participants. Mean peak BAL was 101 ± 15 mg/dL. Alcohol significantly increased brain [11C]PBR28 VT (n = 8; F(1,49) = 34.72, p > 0.0001; Cohen's d'=0.8-1.7) throughout brain by 9-16%. Alcohol significantly altered plasma cytokines TNF-α (F(2,22) = 17.49, p < 0.0001), IL-6 (F(2,22) = 18.00, p > 0.0001), and MCP-1 (F(2,22) = 7.02, p = 0.004). Exploratory analyses identified a negative association between the subjective degree of alcohol intoxication and changes in [11C]PBR28 VT. These findings provide, to our knowledge, the first in vivo human evidence for an acute brain immune response to alcohol.
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Affiliation(s)
- Nakul R Raval
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
| | - Gustavo Angarita
- Yale PET Center, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale University, New Haven, CT, USA
- Department of Neurology, Yale University New Haven, New Haven, CT, USA
| | - Rachel Miller
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Lindsey R Drake
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
| | - Michael Kapinos
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale School of Engineering and Applied Science, New Haven, CT, USA
| | | | - Kelly P Cosgrove
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Yale PET Center, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Ansel T Hillmer
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.
- Yale PET Center, Yale University, New Haven, CT, USA.
- Department of Psychiatry, Yale University, New Haven, CT, USA.
- Department of Biomedical Engineering, Yale School of Engineering and Applied Science, New Haven, CT, USA.
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Raval NR, Wetherill RR, Wiers CE, Dubroff JG, Hillmer AT. Positron Emission Tomography of Neuroimmune Responses in Humans: Insights and Intricacies. Semin Nucl Med 2023; 53:213-229. [PMID: 36270830 DOI: 10.1053/j.semnuclmed.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 08/30/2022] [Indexed: 11/06/2022]
Abstract
The brain's immune system plays a critical role in responding to immune challenges and maintaining homeostasis. However, dysregulated neuroimmune function contributes to neurodegenerative disease and neuropsychiatric conditions. In vivo positron emission tomography (PET) imaging of the neuroimmune system has facilitated a greater understanding of its physiology and the pathology of some neuropsychiatric conditions. This review presents an in-depth look at PET findings from human neuroimmune function studies, highlighting their importance in current neuropsychiatric research. Although the majority of human PET studies feature radiotracers targeting the translocator protein 18 kDa (TSPO), this review also considers studies with other neuroimmune targets, including monoamine oxidase B, cyclooxygenase-1 and cyclooxygenase-2, nitric oxide synthase, and the purinergic P2X7 receptor. Promising new targets, such as colony-stimulating factor 1, Sphingosine-1-phosphate receptor 1, and the purinergic P2Y12 receptor, are also discussed. The significance of validating neuroimmune targets and understanding their function and expression is emphasized in this review to better identify and interpret PET results.
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Affiliation(s)
- Nakul R Raval
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT
| | - Reagan R Wetherill
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Corinde E Wiers
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ansel T Hillmer
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Yale PET Center, Yale University, New Haven, CT; Department of Psychiatry, Yale University, New Haven, CT.
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Rodina AV, Semochkina YP, Vysotskaya OV, Parfenova AA, Moskaleva EY. Radiation-induced neuroinflammation monitoring by the level of peripheral blood monocytes with high expression of translocator protein. Int J Radiat Biol 2023; 99:1364-1377. [PMID: 36821843 DOI: 10.1080/09553002.2023.2177765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 01/11/2023] [Accepted: 02/01/2023] [Indexed: 02/25/2023]
Abstract
PURPOSE Currently there are no effective diagnostic methods for the control of neuroinflammation before manifestation of cognitive impairment after head irradiation. The translocator protein (TSPO) is highly expressed in glial cells upon brain damage, therefore we compared the changes in the number of cells with high TSPO expression in the brain and peripheral blood during radiation-induced neuroinflammation. MATERIALS AND METHODS Hippocampal cytokines mRNA expression and the content of cells with high TSPO expression in the brain and peripheral blood monocytes were analyzed up to eight months after mice head γ-irradiation at a dose of 2 Gy or 8Gy. RESULTS Mice irradiation at a dose of 8 Gy causes neuroinflammation, accompanied by an increase of M1 microglia and TSPOhigh cells in the brain, elevated gene expression of pro-inflammatory and decreased of anti-inflammatory cytokines along with an increased number of microglia and astrocytes in the hippocampus. The content of TSPOhigh cells in the brain correlates with the level TSPOhigh monocytes in three days, one month and two months after exposure. CONCLUSIONS An increase in the level of the monocytes with high expression of TSPO may be considered as a marker for an early diagnostics of post-radiation brain damage leading to cognitive impairment.
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Affiliation(s)
- Alla V Rodina
- Department of Cell Biology, Immunology and Molecular Medicine, Kurchatov Complex of NBICS Technologies, NRC Kurchatov Institute, Moscow, Russian Federation
| | - Yulia P Semochkina
- Department of Cell Biology, Immunology and Molecular Medicine, Kurchatov Complex of NBICS Technologies, NRC Kurchatov Institute, Moscow, Russian Federation
| | - Olga V Vysotskaya
- Department of Cell Biology, Immunology and Molecular Medicine, Kurchatov Complex of NBICS Technologies, NRC Kurchatov Institute, Moscow, Russian Federation
| | - Anna A Parfenova
- Department of Cell Biology, Immunology and Molecular Medicine, Kurchatov Complex of NBICS Technologies, NRC Kurchatov Institute, Moscow, Russian Federation
| | - Elizaveta Y Moskaleva
- Department of Cell Biology, Immunology and Molecular Medicine, Kurchatov Complex of NBICS Technologies, NRC Kurchatov Institute, Moscow, Russian Federation
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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] [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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Gouilly D, Saint-Aubert L, Ribeiro MJ, Salabert AS, Tauber C, Péran P, Arlicot N, Pariente J, Payoux P. Neuroinflammation PET imaging of the translocator protein (TSPO) in Alzheimer's disease: an update. Eur J Neurosci 2022; 55:1322-1343. [PMID: 35083791 DOI: 10.1111/ejn.15613] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/28/2022]
Abstract
Neuroinflammation is a significant contributor to Alzheimer's disease (AD). Until now, PET imaging of the translocator protein (TSPO) has been widely used to depict the neuroimmune endophenotype of AD. The aim of this review was to provide an update to the results from 2018 and to advance the characterization of the biological basis of TSPO imaging in AD by re-examining TSPO function and expression and the methodological aspects of interest. Although the biological basis of the TSPO PET signal is obviously related to microglia and astrocytes in AD, the observed process remains uncertain and might not be directly related to neuroinflammation. Further studies are required to re-examine the cellular significance underlying a variation in the PET signal in AD and how it can be impacted by a disease-modifying treatment.
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Affiliation(s)
- Dominique Gouilly
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Laure Saint-Aubert
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Maria-Joao Ribeiro
- Department of Nuclear Medicine, CHU, Tours, France.,UMR 1253, iBrain, Université de Tours, France.,Inserm CIC 1415, CHRU, Tours, France
| | - Anne-Sophie Salabert
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Nuclear Medicine, CHU, Toulouse, France
| | | | - Patrice Péran
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
| | - Nicolas Arlicot
- UMR 1253, iBrain, Université de Tours, France.,Inserm CIC 1415, CHRU, Tours, France
| | - Jérémie Pariente
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Cognitive Neurology, Epilepsy and Movement Disorders, CHU, Toulouse, France.,Center of Clinical Investigations (CIC1436), CHU, Toulouse, France
| | - Pierre Payoux
- ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.,Department of Nuclear Medicine, CHU, Toulouse, France
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9
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Translocator Protein Regulate Polarization Phenotype Transformation of Microglia after Cerebral Ischemia-reperfusion Injury. Neuroscience 2021; 480:203-216. [PMID: 34624453 DOI: 10.1016/j.neuroscience.2021.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022]
Abstract
Microglia cells are activated after cerebral ischemia-reperfusion injury (CIRI), playing a dual role in aggravating the injury or promoting tissue repair by polarization. Translocator protein (TSPO) is a biomarker of neuroinflammation or microglia activation. Its expression is significantly increased while brain injury and neuroinflammation occur. However, the relationship between TSPO and microglia polarization in CIRI is still not clear. In the present study, the middle cerebral artery occlusion (MCAO) methods in rats were used to simulate CIRI. We found that the expressions of M1 markers (CD86, IL-1β, and TNF-α) and M2 markers (CD206, IL-10, and TGF-β) were significantly increased. Moreover, the injection of TSPO ligand, PK11195, inhibited the increase of M1 polarization markers but promoted the expressions of M2 polarization markers, which significantly ameliorated the neurological damage after MCAO in rats. In vitro studies showed that shRNA-mediated TSPO knock-down promoted M1 polarization but inhibited M2 polarization, accompanied by a significant decrease in cell viability. On the contrary, overexpression of TSPO inhibited M1 polarization, promoted M2 polarization, and significantly improved cell viability. In summary, TSPO plays a neuroprotective role in CIRI by inhibiting M1 polarization and promoting M2 polarization, which suggests that TSPO may have the potential to serve as a therapeutic target for stroke.
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10
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Contribution of TSPO imaging in the understanding of the state of gliosis in substance use disorders. Eur J Nucl Med Mol Imaging 2021; 49:186-200. [PMID: 34041563 DOI: 10.1007/s00259-021-05408-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/10/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE Recent research in last years in substance use disorders (SUD) synthesized a proinflammatory hypothesis of SUD based on reported pieces of evidence of non-neuronal central immune signalling pathways modulated by drug of abuse and that contribute to their pharmacodynamic actions. Positron emission tomography has been shown to be a precious imaging technique to study in vivo neurochemical processes involved in SUD and to highlight the central immune signalling actions of drugs of abuse. METHODS In this review, we investigate the contribution of the central immune system, with a particular focus on translocator protein 18 kDa (TSPO) imaging, associated with a series of drugs involved in substance use disorders (SUD) specifically alcohol, opioids, tobacco, methamphetamine, cocaine, and cannabis. RESULTS The large majority of preclinical and clinical studies presented in this review converges towards SUD modulation of the neuroimmune responses and TSPO expression and speculated a pivotal positioning in the pathogenesis of SUD. However, some contradictions concerning the same drug or between preclinical and clinical studies make it difficult to draw a clear picture about the significance of glial state in SUD. DISCUSSION Significant disparities in clinical and biological characteristics are present between investigated populations among studies. Heterogeneity in genetic factors and other clinical co-morbidities, difficult to be reproduced in animal models, may affect findings. On the other hand, technical aspects including study designs, radioligand limitations, or PET imaging quantification methods could impact the study results and should be considered to explain discrepancies in outcomes. CONCLUSION The supposed neuroimmune component of SUD provides new therapeutic approaches in the prediction and treatment of SUD pointing to the central immune signalling.
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11
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Torrado-Carvajal A, Toschi N, Albrecht DS, Chang K, Akeju O, Kim M, Edwards RR, Zhang Y, Hooker JM, Duggento A, Kalpathy-Cramer J, Napadow V, Loggia ML. Thalamic neuroinflammation as a reproducible and discriminating signature for chronic low back pain. Pain 2021; 162:1241-1249. [PMID: 33065737 DOI: 10.1097/j.pain.0000000000002108] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022]
Abstract
ABSTRACT Using positron emission tomography, we recently demonstrated elevated brain levels of the 18 kDa translocator protein (TSPO), a glial activation marker, in chronic low back pain (cLBP) patients, compared to healthy controls (HCs). Here, we first sought to replicate the original findings in an independent cohort (15 cLBP, 37.8 ± 12.5 y/o; 18 HC, 48.2 ± 12.8 y/o). We then trained random forest machine learning algorithms based on TSPO imaging features combining discovery and replication cohorts (totaling 25 cLBP, 42.4 ± 13.2 y/o; 27 HC, 48.9 ± 12.6 y/o), to explore whether image features other than the mean contain meaningful information that might contribute to the discrimination of cLBP patients and HC. Feature importance was ranked using SHapley Additive exPlanations values, and the classification performance (in terms of area under the curve values) of classifiers containing only the mean, other features, or all features was compared using the DeLong test. Both region-of-interest and voxelwise analyses replicated the original observation of thalamic TSPO signal elevations in cLBP patients compared to HC (P < 0.05). The random forest-based analyses revealed that although the mean is a discriminating feature, other features demonstrate similar level of importance, including the maximum, kurtosis, and entropy. Our observations suggest that thalamic neuroinflammatory signal is a reproducible and discriminating feature for cLBP, further supporting a role for glial activation in human cLBP, and the exploration of neuroinflammation as a therapeutic target for chronic pain. This work further shows that TSPO signal contains a richness of information that the simple mean might fail to capture completely.
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Affiliation(s)
- Angel Torrado-Carvajal
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.,Medical Image Analysis and Biometry Laboratory, Universidad Rey Juan Carlos, Madrid, Spain
| | - Nicola Toschi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.,Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Daniel S Albrecht
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Ken Chang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Oluwaseun Akeju
- Department of Anesthesia, Critical Care and Pain Medicine, MGH/HMS, Boston, MA, United States
| | - Minhae Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Robert R Edwards
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, HMS, Boston, MA, United States
| | - Yi Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, MGH/HMS, Boston, MA, United States
| | - Jacob M Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Andrea Duggento
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.,Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Jayashree Kalpathy-Cramer
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Vitaly Napadow
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Marco L Loggia
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
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12
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Aertker BM, Kumar A, Cardenas F, Gudenkauf F, Sequeira D, Prossin AR, Srivastava AK, Cox CS, Bedi SS. PET Imaging of Peripheral Benzodiazepine Receptor Standard Uptake Value Increases After Controlled Cortical Impact, a Rodent Model of Traumatic Brain Injury. ASN Neuro 2021; 13:17590914211014135. [PMID: 33957800 PMCID: PMC8172335 DOI: 10.1177/17590914211014135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Traumatic brain injury (TBI) is a chronic, life threatening injury for which few
effective interventions are available. Evidence in animal models suggests
un-checked immune activation may contribute to the pathophysiology. Changes in
regional density of active brain microglia can be quantified in vivo with
positron emission topography (PET) with the relatively selective radiotracer,
peripheral benzodiazepine receptor 28 (11 C-PBR28). Phenotypic assessment
(activated vs resting) can subsequently be assessed (ex vivo) using
morphological techniques. To elucidate the mechanistic contribution of immune
cells in due to TBI, we employed a hybrid approach involving both in vivo
(11 C-PBR28 PET) and ex vivo (morphology) to elucidate the role of immune cells
in a controlled cortical impact (CCI), a rodent model for TBI. Density of
activated brain microglia/macrophages was quantified 120 hours after injury
using the standardized uptake value (SUV) approach. Ex vivo morphological
analysis from specific brain regions using IBA-1 antibodies differentiated
ramified (resting) from amoeboid (activated) immune cells. Additional
immunostaining of PBRs facilitated co-localization of PBRs with IBA-1 staining
to further validate PET data. Injured animals displayed greater PBR28suv when
compared to sham animals. Immunohistochemistry demonstrated elevated density of
amoeboid microglia/macrophages in the ipsilateral dentate gyrus, corpus
callosum, thalami and injury penumbra of injured animals compared to sham
animals. PBR co-stained with amoeboid microglia/macrophages in the injury
penumbra and not with astrocytes. These data suggest the technologies evaluated
may serve as bio-signatures of neuroinflammation following severe brain injury
in small animals, potentially enabling in vivo tracking of neuroinflammation
following TBI and cellular-based therapies.
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Affiliation(s)
- Benjamin M Aertker
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Akshita Kumar
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Fanni Cardenas
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Franciska Gudenkauf
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - David Sequeira
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Alan R Prossin
- Department of Psychiatry and Behavioral Sciences, University of Texas Medical School at Houston, Texas, United States
| | - Amit K Srivastava
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Charles S Cox
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
| | - Supinder S Bedi
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Texas, United States
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13
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Abstract
Microglia, the main immune cell of the central nervous system (CNS), categorized into M1-like phenotype and M2-like phenotype, play important roles in phagocytosis, cell migration, antigen presentation, and cytokine production. As a part of CNS, retinal microglial cells (RMC) play an important role in retinal diseases. Diabetic retinopathy (DR) is one of the most common complications of diabetes. Recent studies have demonstrated that DR is not only a microvascular disease but also retinal neurodegeneration. RMC was regarded as a central role in neurodegeneration and neuroinflammation. Therefore, in this review, we will discuss RMC polarization and its possible regulatory factors in early DR, which will provide new targets and insights for early intervention of DR.
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14
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Schober ME, Requena DF, Ohde JW, Maves S, Pauly JR. Docosahexaenoic acid decreased inflammatory gene expression, but not 18-kDa translocator protein binding, in rat pup brain after controlled cortical impact. J Trauma Acute Care Surg 2021; 90:866-873. [PMID: 33728886 PMCID: PMC8068600 DOI: 10.1097/ta.0000000000003084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Traumatic brain injury is the leading cause of acquired neurologic disability in children. In our model of pediatric traumatic brain injury, controlled cortical impact (CCI) in rat pups, docosahexaenoic acid (DHA) improved lesion volume and cognitive testing as late as postinjury day (PID) 50. Docosahexaenoic acid decreased proinflammatory messenger RNA (mRNA) in microglia and macrophages at PIDs 3 and 7, but not 30. We hypothesized that DHA affected inflammatory markers differentially relative to impact proximity, early and persistently after CCI. METHODS To provide a temporal snapshot of regional neuroinflammation, we measured 18-kDa translocator protein (TSPO) binding using whole brain autoradiography at PIDs 3, 7, 30, and 50. Guided by TSPO results, we measured mRNA levels in contused cortex and underlying hippocampus for genes associated with proinflammatory and inflammation-resolving states at PIDs 2 and 3. RESULTS Controlled cortical impact increased TSPO binding at all time points, most markedly at PID 3 and in regions closest to impact, not blunted by DHA. Controlled cortical impact increased cortical and hippocampal mRNA proinflammatory markers, blunted by DHA at PID 2 in hippocampus. CONCLUSION Controlled cortical impact increased TSPO binding in the immature brain in a persistent manner more intensely with more severe injury, not altered by DHA. Controlled cortical impact increased PIDs 2 and 3 mRNA levels of proinflammatory and inflammation-resolving genes. Docosahexaenoic acid decreased proinflammatory markers associated with inflammasome activation at PID 2. We speculate that DHA's salutary effects on long-term outcomes result from early effects on the inflammasome. Future studies will examine functional effects of DHA on microglia both early and late after CCI.
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Affiliation(s)
- Michelle Elena Schober
- From the Primary Children's Hospital (M.E.S.), and Division of Critical Care, Department of Pediatrics (M.E.S., D.F.R., S.M.), University of Utah, Salt Lake City, Utah; and Department of Pharmaceutical Sciences (J.W.O., J.K.P.), College of Pharmacy, University of Kentucky, Lexington, Kentucky
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15
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Banerji R, Huynh C, Figueroa F, Dinday MT, Baraban SC, Patel M. Enhancing glucose metabolism via gluconeogenesis is therapeutic in a zebrafish model of Dravet syndrome. Brain Commun 2021; 3:fcab004. [PMID: 33842883 PMCID: PMC8023476 DOI: 10.1093/braincomms/fcab004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 01/18/2023] Open
Abstract
Energy-producing pathways are novel therapeutic targets for the treatment of neurodevelopmental disorders. Here, we focussed on correcting metabolic defects in a catastrophic paediatric epilepsy, Dravet syndrome which is caused by mutations in sodium channel NaV1.1 gene, SCN1A. We utilized a translatable zebrafish model of Dravet syndrome (scn1lab) which exhibits key characteristics of patients with Dravet syndrome and shows metabolic deficits accompanied by down-regulation of gluconeogenesis genes, pck1 and pck2. Using a metabolism-based small library screen, we identified compounds that increased gluconeogenesis via up-regulation of pck1 gene expression in scn1lab larvae. Treatment with PK11195, a pck1 activator and a translocator protein ligand, normalized dys-regulated glucose levels, metabolic deficits, translocator protein expression and significantly decreased electrographic seizures in mutant larvae. Inhibition of pck1 in wild-type larvae mimicked metabolic and behaviour defects observed in scn1lab mutants. Together, this suggests that correcting dys-regulated metabolic pathways can be therapeutic in neurodevelopmental disorders such as Dravet syndrome arising from ion channel dysfunction.
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Affiliation(s)
- Rajeswari Banerji
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, CA 80045, USA
| | - Christopher Huynh
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, CA 80045, USA
| | - Francisco Figueroa
- Department of Neurological Surgery, Epilepsy Research Laboratory, University of California, San Francisco, CA 94143, USA
| | - Matthew T Dinday
- Department of Neurological Surgery, Epilepsy Research Laboratory, University of California, San Francisco, CA 94143, USA
| | - Scott C Baraban
- Department of Neurological Surgery, Epilepsy Research Laboratory, University of California, San Francisco, CA 94143, USA
| | - Manisha Patel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, CA 80045, USA
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16
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Loth MK, Guariglia SR, Re DB, Perez J, de Paiva VN, Dziedzic JL, Chambers JW, Azzam DJ, Guilarte TR. A Novel Interaction of Translocator Protein 18 kDa (TSPO) with NADPH Oxidase in Microglia. Mol Neurobiol 2020; 57:4467-4487. [PMID: 32743737 PMCID: PMC7515859 DOI: 10.1007/s12035-020-02042-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 07/24/2020] [Indexed: 12/12/2022]
Abstract
In the brain neuropil, translocator protein 18 kDa (TSPO) is a stress response protein that is upregulated in microglia and astrocytes in diverse central nervous system pathologies. TSPO is widely used as a biomarker of neuroinflammation in preclinical and clinical neuroimaging studies. However, there is a paucity of knowledge on the function(s) of TSPO in glial cells. In this study, we explored a putative interaction between TSPO and NADPH oxidase 2 (NOX2) in microglia. We found that TSPO associates with gp91phox and p22phox, the principal subunits of NOX2 in primary murine microglia. The association of TSPO with gp91phox and p22phox was observed using co-immunoprecipitation, confocal immunofluorescence imaging, and proximity ligation assay. We found that besides gp91phox and p22phox, voltage-dependent anion channel (VDAC) also co-immunoprecipitated with TSPO consistent with previous reports. When we compared lipopolysaccharide (LPS) stimulated microglia to vehicle control, we found that a lower amount of gp91phox and p22phox protein co-immunoprecipitated with TSPO suggesting a disruption of the TSPO-NOX2 subunits association. TSPO immuno-gold electron microscopy confirmed that TSPO is present in the outer mitochondrial membrane but it is also found in the endoplasmic reticulum (ER), mitochondria-associated ER membrane (MAM), and in the plasma membrane. TSPO localization at the MAM may represent a subcellular site where TSPO interacts with gp91phox and p22phox since the MAM is a point of communication between outer mitochondria membrane proteins (TSPO) and ER proteins (gp91phox and p22phox) where they mature and form the cytochrome b558 (Cytb558) heterodimer. We also found that an acute burst of reactive oxygen species (ROS) increased TSPO levels on the surface of microglia and this effect was abrogated by a ROS scavenger. These results suggest that ROS production may alter the subcellular distribution of TSPO. Collectively, our findings suggest that in microglia, TSPO is associated with the major NOX2 subunits gp91phox and p22phox. We hypothesize that this interaction may regulate Cytb558 formation and modulate NOX2 levels, ROS production, and redox homeostasis in microglia.
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Affiliation(s)
- Meredith K Loth
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Sara R Guariglia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Diane B Re
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Juan Perez
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA
| | - Vanessa Nunes de Paiva
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA
| | - Jennifer L Dziedzic
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA
| | - Jeremy W Chambers
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA
| | - Diana J Azzam
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA
| | - Tomás R Guilarte
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA.
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, 33199, USA.
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17
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Yao R, Pan R, Shang C, Li X, Cheng J, Xu J, Li Y. Translocator Protein 18 kDa (TSPO) Deficiency Inhibits Microglial Activation and Impairs Mitochondrial Function. Front Pharmacol 2020; 11:986. [PMID: 32695005 PMCID: PMC7339871 DOI: 10.3389/fphar.2020.00986] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022] Open
Abstract
TSPO is mainly expressed in the mitochondrial outer membrane of microglia in the central nervous system, and its expression is greatly increased when microglia are activated. However, the role and mechanism of this protein in microglial activation is not well characterized. In this study, we investigated the role of TSPO in microglial activation by isolating primary microglia from TSPO knockout mice and constructing TSPO-knockdown microglial cell line. We found that TSPO deficiency significantly inhibited microglial activation induced by LPS or IL-4. Mechanistically, TSPO deficiency greatly decreased the mitochondrial membrane potential and ATP production. Moreover, an analysis of cellular energy metabolism showed that TSPO deficiency suppressed mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis, resulting in microglial overall metabolic deficits. Together, our results reveal a crucial role of TSPO in microglial activation through the regulation of mitochondrial metabolism, thus providing a potential therapeutic target for neuroinflammation-related diseases of the central nervous system.
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Affiliation(s)
- Rumeng Yao
- Department of Neuropharmacology and Drug Discovery, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.,State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Ruiyuan Pan
- The State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Chao Shang
- Institute of Military Veterinary Medicine, Academy of Military Medical Science, Changchun, China
| | - Xiaoheng Li
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jinbo Cheng
- Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Traditional Chinese Medicine, Nanchang, China.,Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
| | - Jiangping Xu
- Department of Neuropharmacology and Drug Discovery, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.,Central Laboratory, Southern Medical University, Guangzhou, China
| | - Yunfeng Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
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18
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Nutma E, Stephenson JA, Gorter RP, de Bruin J, Boucherie DM, Donat CK, Breur M, van der Valk P, Matthews PM, Owen DR, Amor S. A quantitative neuropathological assessment of translocator protein expression in multiple sclerosis. Brain 2020; 142:3440-3455. [PMID: 31578541 PMCID: PMC6821167 DOI: 10.1093/brain/awz287] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/11/2019] [Accepted: 07/25/2019] [Indexed: 01/09/2023] Open
Abstract
The 18 kDa translocator protein (TSPO) is increasingly used to study brain and spinal cord inflammation in degenerative diseases of the CNS such as multiple sclerosis. The enhanced TSPO PET signal that arises during disease is widely considered to reflect activated pathogenic microglia, although quantitative neuropathological data to support this interpretation have not been available. With the increasing interest in the role of chronic microglial activation in multiple sclerosis, characterising the cellular neuropathology associated with TSPO expression is of clear importance for understanding the cellular and pathological processes on which TSPO PET imaging is reporting. Here we have studied the cellular expression of TSPO and specific binding of two TSPO targeting radioligands (3H-PK11195 and 3H-PBR28) in tissue sections from 42 multiple sclerosis cases and 12 age-matched controls. Markers of homeostatic and reactive microglia, astrocytes, and lymphocytes were used to investigate the phenotypes of cells expressing TSPO. There was an approximate 20-fold increase in cells double positive for TSPO and HLA-DR in active lesions and in the rim of chronic active lesion, relative to normal appearing white matter. TSPO was uniformly expressed across myeloid cells irrespective of their phenotype, rather than being preferentially associated with pro-inflammatory microglia or macrophages. TSPO+ astrocytes were increased up to 7-fold compared to normal-appearing white matter across all lesion subtypes and accounted for 25% of the TSPO+ cells in these lesions. To relate TSPO protein expression to ligand binding, specific binding of the TSPO ligands 3H-PK11195 and 3H-PBR28 was determined in the same lesions. TSPO radioligand binding was increased up to seven times for 3H-PBR28 and up to two times for 3H-PK11195 in active lesions and the centre of chronic active lesions and a strong correlation was found between the radioligand binding signal for both tracers and the number of TSPO+ cells across all of the tissues examined. In summary, in multiple sclerosis, TSPO expression arises from microglia of different phenotypes, rather than being restricted to microglia which express classical pro-inflammatory markers. While the majority of cells expressing TSPO in active lesions or chronic active rims are microglia/macrophages, our findings also emphasize the significant contribution of activated astrocytes, as well as smaller contributions from endothelial cells. These observations establish a quantitative framework for interpretation of TSPO in multiple sclerosis and highlight the need for neuropathological characterization of TSPO expression for the interpretation of TSPO PET in other neurodegenerative disorders.
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Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands
| | - Jodie A Stephenson
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands.,Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Rianne P Gorter
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands
| | - Joy de Bruin
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands
| | | | | | - Marjolein Breur
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands
| | - Paul van der Valk
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands
| | - Paul M Matthews
- Department of Brain Sciences, Imperial College London, UK.,UK Dementia Research Institute, Imperial College London, UK
| | - David R Owen
- Department of Brain Sciences, Imperial College London, UK
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, Location VUmc, The Netherlands.,Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
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19
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Bezukladova S, Tuisku J, Matilainen M, Vuorimaa A, Nylund M, Smith S, Sucksdorff M, Mohammadian M, Saunavaara V, Laaksonen S, Rokka J, Rinne JO, Rissanen E, Airas L. Insights into disseminated MS brain pathology with multimodal diffusion tensor and PET imaging. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2020; 7:e691. [PMID: 32123046 PMCID: PMC7136049 DOI: 10.1212/nxi.0000000000000691] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/09/2020] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To evaluate in vivo the co-occurrence of microglial activation and microstructural white matter (WM) damage in the MS brain and to examine their association with clinical disability. METHODS 18-kDa translocator protein (TSPO) brain PET imaging was performed for evaluation of microglial activation by using the radioligand [11C](R)-PK11195. TSPO binding was evaluated as the distribution volume ratio (DVR) from dynamic PET images. Diffusion tensor imaging (DTI) and conventional MRI (cMRI) were performed at the same time. Mean fractional anisotropy (FA) and mean (MD), axial, and radial (RD) diffusivities were calculated within the whole normal-appearing WM (NAWM) and segmented NAWM regions appearing normal in cMRI. Fifty-five patients with MS and 15 healthy controls (HCs) were examined. RESULTS Microstructural damage was observed in the NAWM of the MS brain. DTI parameters of patients with MS were significantly altered in the NAWM compared with an age- and sex-matched HC group: mean FA was decreased, and MD and RD were increased. These structural abnormalities correlated with increased TSPO binding in the whole NAWM and in the temporal NAWM (p < 0.05 for all correlations; p < 0.01 for RD in the temporal NAWM). Both compromised WM integrity and increased microglial activation in the NAWM correlated significantly with higher clinical disability measured with the Expanded Disability Status Scale score. CONCLUSIONS Widespread structural disruption in the NAWM is linked to neuroinflammation, and both phenomena associate with clinical disability. Multimodal PET and DTI allow in vivo evaluation of widespread MS pathology not visible using cMRI.
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Affiliation(s)
- Svetlana Bezukladova
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Jouni Tuisku
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Markus Matilainen
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Anna Vuorimaa
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Marjo Nylund
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Sarah Smith
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Marcus Sucksdorff
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Mehrbod Mohammadian
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Virva Saunavaara
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Sini Laaksonen
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Johanna Rokka
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Juha O Rinne
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Eero Rissanen
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland
| | - Laura Airas
- From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland.
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20
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Dimitrova-Shumkovska J, Krstanoski L, Veenman L. Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update. Cells 2020; 9:cells9040870. [PMID: 32252470 PMCID: PMC7226777 DOI: 10.3390/cells9040870] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/30/2020] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.
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Affiliation(s)
- Jasmina Dimitrova-Shumkovska
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
- Correspondence: (J.D.-S.); (L.V.)
| | - Ljupcho Krstanoski
- Department of Experimental Biochemistry, Institute of Biology, Faculty of Natural Sciences and Mathematics, University Ss Cyril and Methodius, Arhimedova 3, P.O. Box 162, 1000 Skopje, Republic of North Macedonia;
| | - Leo Veenman
- Technion-Israel Institute of Technology, Faculty of Medicine, Rappaport Institute of Medical Research, 1 Efron Street, P.O. Box 9697, Haifa 31096, Israel
- Correspondence: (J.D.-S.); (L.V.)
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21
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Vegeto E, Villa A, Della Torre S, Crippa V, Rusmini P, Cristofani R, Galbiati M, Maggi A, Poletti A. The Role of Sex and Sex Hormones in Neurodegenerative Diseases. Endocr Rev 2020; 41:5572525. [PMID: 31544208 PMCID: PMC7156855 DOI: 10.1210/endrev/bnz005] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
Neurodegenerative diseases (NDs) are a wide class of disorders of the central nervous system (CNS) with unknown etiology. Several factors were hypothesized to be involved in the pathogenesis of these diseases, including genetic and environmental factors. Many of these diseases show a sex prevalence and sex steroids were shown to have a role in the progression of specific forms of neurodegeneration. Estrogens were reported to be neuroprotective through their action on cognate nuclear and membrane receptors, while adverse effects of male hormones have been described on neuronal cells, although some data also suggest neuroprotective activities. The response of the CNS to sex steroids is a complex and integrated process that depends on (i) the type and amount of the cognate steroid receptor and (ii) the target cell type-either neurons, glia, or microglia. Moreover, the levels of sex steroids in the CNS fluctuate due to gonadal activities and to local metabolism and synthesis. Importantly, biochemical processes involved in the pathogenesis of NDs are increasingly being recognized as different between the two sexes and as influenced by sex steroids. The aim of this review is to present current state-of-the-art understanding on the potential role of sex steroids and their receptors on the onset and progression of major neurodegenerative disorders, namely, Alzheimer's disease, Parkinson's diseases, amyotrophic lateral sclerosis, and the peculiar motoneuron disease spinal and bulbar muscular atrophy, in which hormonal therapy is potentially useful as disease modifier.
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Affiliation(s)
- Elisabetta Vegeto
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Alessandro Villa
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze della Salute (DiSS), Università degli Studi di Milano, Italy
| | - Sara Della Torre
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Valeria Crippa
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Paola Rusmini
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Riccardo Cristofani
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Mariarita Galbiati
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
| | - Adriana Maggi
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Scienze Farmaceutiche (DiSFarm), Università degli Studi di Milano, Italy
| | - Angelo Poletti
- Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Italy.,Dipartimento di Eccellenza di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Italy
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22
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Caplan HW, Cardenas F, Gudenkauf F, Zelnick P, Xue H, Cox CS, Bedi SS. Spatiotemporal Distribution of Microglia After Traumatic Brain Injury in Male Mice. ASN Neuro 2020; 12:1759091420911770. [PMID: 32146827 PMCID: PMC7066592 DOI: 10.1177/1759091420911770] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Traumatic brain injury (TBI) disrupts the complex arrangement of glia and neuronal cells in the central nervous system. Microglia, the resident immune cells, survey the cellular milieu under homeostatic conditions and play a neuroprotective role via clearance of dead cells and debris such as axons and myelin. Resting (ramified) microglia possess a distinct morphology—small rod-shaped somata with thin processes. After TBI, microglia are activated and transition into an amoeboid morphology. To delineate the spatiotemporal morphological response of microglia after TBI, we used a controlled cortical impact injury model to quantify and characterize microglia at 24 hr and 28 days after TBI in the hippocampus (H) and lateral posterior nucleus of the thalamus (LPNT). Increased numbers of microglia were observed in the H and LPNT at 28 days after controlled cortical impact, but not at 24 hr in comparison to controls. Spatially, controlled cortical impact resulted in an increase of amoeboid microglia bilaterally at 24 hr and 28 days in H and ipsilaterally in LPNT. Temporally, at 28 days, TBI resulted in a significant increase in the number of amoeboid microglia in both H and LPNT. In addition, at 28 days after injury, we observed an increase in translocator protein, a marker for activated microglia, in the ipsilateral thalamus only. TBI results in a spatiotemporal increase in amoeboid microglia in the hippocampus and the LPNT over 28 days. Delineating their spatiotemporal phenotype is critical because it can help identify therapeutic targets with appropriate therapy.
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Affiliation(s)
- Henry W Caplan
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Fanni Cardenas
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Franciska Gudenkauf
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Pamela Zelnick
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Hasen Xue
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Charles S Cox
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
| | - Supinder S Bedi
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Science Center at Houston
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23
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Fan J, Campioli E, Sottas C, Zirkin B, Papadopoulos V. Amhr2-Cre-Mediated Global Tspo Knockout. J Endocr Soc 2020; 4:bvaa001. [PMID: 32099945 PMCID: PMC7031085 DOI: 10.1210/jendso/bvaa001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/27/2022] Open
Abstract
Although the role of translocator protein (TSPO) in cholesterol transport in steroid-synthesizing cells has been studied extensively, recent studies of TSPO genetic depletion have questioned its role. Amhr2-Cre mice have been used to generate Leydig cell-specific Tspo conditional knockout (cKO) mice. Using the same Cre line, we were unable to generate Tspo cKO mice possibly because of genetic linkage between Tspo and Amhr2 and coexpression of Amhr2-Cre and Tspo in early embryonic development. We found that Amhr2-Cre is expressed during preimplantation stages, resulting in global heterozygous mice (gHE; Amhr2-Cre+/–,Tspo–/+). Two gHE mice were crossed, generating Amhr2-Cre–mediated Tspo global knockout (gKO; Tspo–/–) mice. We found that 33.3% of blastocysts at E3.5 to E4.5 showed normal morphology, whereas 66.7% showed delayed development, which correlates with the expected Mendelian proportions of Tspo+/+ (25%), Tspo–/– (25%), and Tspo+/– (50%) genotypes from crossing 2 Tspo–/+ mice. Adult Tspo gKO mice exhibited disturbances in neutral lipid homeostasis and reduced intratesticular and circulating testosterone levels, but no change in circulating basal corticosterone levels. RNA-sequencing data from mouse adrenal glands and lungs revealed transcriptome changes in response to the loss of TSPO, including changes in several cholesterol-binding and transfer proteins. This study demonstrates that Amhr2-Cre can be used to produce Tspo gKO mice instead of cKO, and can serve as a new global “Cre deleter.” Moreover, our results show that Tspo deletion causes delayed preimplantation embryonic development, alters neutral lipid storage and steroidogenesis, and leads to transcriptome changes that may reflect compensatory mechanisms in response to the loss of function of TSPO.
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Affiliation(s)
- Jinjiang Fan
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Enrico Campioli
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Chantal Sottas
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
| | - Barry Zirkin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, US
| | - Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, US
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24
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Tang D, Li J, Nickels ML, Huang G, Cohen AS, Manning HC. Preclinical Evaluation of a Novel TSPO PET Ligand 2-(7-Butyl-2-(4-(2-[ 18F]Fluoroethoxy)phenyl)-5-Methylpyrazolo[1,5-a]Pyrimidin-3-yl)-N,N-Diethylacetamide ( 18F-VUIIS1018A) to Image Glioma. Mol Imaging Biol 2019; 21:113-121. [PMID: 29869061 DOI: 10.1007/s11307-018-1198-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE There is an urgent need for the development of novel positron emission tomography (PET) tracers for glioma imaging. In this study, we developed a novel PET probe ([18F]VUIIS1018A) by targeting translocator protein (TSPO), an imaging biomarker for glioma. The purpose of this preclinical study was to evaluate this novel TSPO probe for glioma imaging. PROCEDURES In this study, we synthesized [19F]VUIIS1018A and the precursor for radiosynthesis of [18F]VUIIS1018A. TSPO binding affinity was confirmed using a radioligand competitive binding assay in C6 glioma cell lysate. Further, dynamic imaging studies were performed in rats using a microPET system. These studies include displacement and blocking studies for ligand reversibility and specificity evaluation, and compartment modeling of PET data for pharmacokinetic parameter measurement using metabolite-corrected arterial input functions and PMOD. RESULTS Compared to previously reported TSPO tracers including [18F]VUIIS1008 and [18F]DPA-714, the novel tracer [18F]VUIIS1018A demonstrated higher binding affinity and BPND. Pretreatment with the cold analog [19F]VUIIS1018A could partially block tumor accumulation of this novel tracer. Further, compartment modeling of this novel tracer also exhibited a greater tumor-to-background ratio, a higher tumor binding potential and a lower brain binding potential when compared with other TSPO probes, such as [18F]DPA-714 and [18F]VUIIS1008. CONCLUSIONS These studies illustrate that [18F]VUIIS1018A can serve as a promising TSPO PET tracer for glioma imaging and potentially imaging of other solid tumors.
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Affiliation(s)
- Dewei Tang
- Center for Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, China.,Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Pudong New District, Shanghai, 200127, China
| | - Jun Li
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael L Nickels
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gang Huang
- Center for Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, China.,Department of Nuclear Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 160 Pujian Road, Pudong New District, Shanghai, 200127, China
| | - Allison S Cohen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA
| | - H Charles Manning
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA. .,Vanderbilt Center for Molecular Probes (CMP), Vanderbilt University Medical School, 1161 21st Ave. S., AA 1105 MCN, Nashville, TN, 37232-2310, USA. .,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA. .,Program in Chemical and Physical Biology, Vanderbilt University Medical Center, Nashville, TN, USA. .,Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA. .,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA. .,Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, USA.
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25
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Shoshan-Barmatz V, Pittala S, Mizrachi D. VDAC1 and the TSPO: Expression, Interactions, and Associated Functions in Health and Disease States. Int J Mol Sci 2019; 20:ijms20133348. [PMID: 31288390 PMCID: PMC6651789 DOI: 10.3390/ijms20133348] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
The translocator protein (TSPO), located at the outer mitochondrial membrane (OMM), serves multiple functions and contributes to numerous processes, including cholesterol import, mitochondrial metabolism, apoptosis, cell proliferation, Ca2+ signaling, oxidative stress, and inflammation. TSPO forms a complex with the voltage-dependent anion channel (VDAC), a protein that mediates the flux of ions, including Ca2+, nucleotides, and metabolites across the OMM, controls metabolism and apoptosis and interacts with many proteins. This review focuses on the two OMM proteins TSPO and VDAC1, addressing their structural interaction and associated functions. TSPO appears to be involved in the generation of reactive oxygen species, proposed to represent the link between TSPO activation and VDAC, thus playing a role in apoptotic cell death. In addition, expression of the two proteins in healthy brains and diseased states is considered, as is the relationship between TSPO and VDAC1 expression. Both proteins are over-expressed in in brains from Alzheimer’s disease patients. Finally, TSPO expression levels were proposed as a biomarker of some neuropathological settings, while TSPO-interacting ligands have been considered as a potential basis for drug development.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Srinivas Pittala
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Dario Mizrachi
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
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26
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Antkowiak B, Rammes G. GABA(A) receptor-targeted drug development -New perspectives in perioperative anesthesia. Expert Opin Drug Discov 2019; 14:683-699. [DOI: 10.1080/17460441.2019.1599356] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Bernd Antkowiak
- Department of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, Eberhard-Karls-University,
Tübingen, Germany
- Department of Anaesthesiology and Intensive Care, Experimental Anaesthesiology Section, Werner Reichardt Center for Integrative Neuroscience, Tübingen,
Germany
| | - Gerhard Rammes
- University Hospital rechts der Isar, Department of Anesthesiology, München,
Germany
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27
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Correale J, Marrodan M, Ysrraelit MC. Mechanisms of Neurodegeneration and Axonal Dysfunction in Progressive Multiple Sclerosis. Biomedicines 2019; 7:biomedicines7010014. [PMID: 30791637 PMCID: PMC6466454 DOI: 10.3390/biomedicines7010014] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 12/14/2022] Open
Abstract
Multiple Sclerosis (MS) is a major cause of neurological disability, which increases predominantly during disease progression as a result of cortical and grey matter structures involvement. The gradual accumulation of disability characteristic of the disease seems to also result from a different set of mechanisms, including in particular immune reactions confined to the Central Nervous System such as: (a) B-cell dysregulation, (b) CD8+ T cells causing demyelination or axonal/neuronal damage, and (c) microglial cell activation associated with neuritic transection found in cortical demyelinating lesions. Other potential drivers of neurodegeneration are generation of oxygen and nitrogen reactive species, and mitochondrial damage, inducing impaired energy production, and intra-axonal accumulation of Ca2+, which in turn activates a variety of catabolic enzymes ultimately leading to progressive proteolytic degradation of cytoskeleton proteins. Loss of axon energy provided by oligodendrocytes determines further axonal degeneration and neuronal loss. Clearly, these different mechanisms are not mutually exclusive and could act in combination. Given the multifactorial pathophysiology of progressive MS, many potential therapeutic targets could be investigated in the future. This remains however, an objective that has yet to be undertaken.
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Affiliation(s)
- Jorge Correale
- Department of Neurology, FLENI, Buenos Aires 1428, Argentina.
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28
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Regional elevations in microglial activation and cerebral glucose utilization in frontal white matter tracts of rhesus monkeys following prolonged cocaine self-administration. Brain Struct Funct 2019; 224:1417-1428. [PMID: 30747315 DOI: 10.1007/s00429-019-01846-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 02/06/2019] [Indexed: 12/18/2022]
Abstract
It has been shown that exposure to cocaine can result in neuroinflammatory responses. Microglia, the resident CNS immune cells, undergo a transition to an activated state when challenged. In rodents, and possibly humans, cocaine exposure activates microglia. The goal of this study was to assess the extent and magnitude of microglial activation in rhesus monkeys with an extensive history of cocaine self-administration. Male rhesus monkeys (N = 4/group) were trained to respond on a fixed-interval 3-min schedule of food or 0.3 mg/kg/injection cocaine presentation (30 reinforcers/session) for 300 sessions. At the end of the final session, monkeys were administered 2-[14C]deoxyglucose intravenously and 45 min later euthanized. Brain sections were used for autoradiographic assessments of glucose utilization and for microglia activation with [3H]PK11195, a marker for the microglial 18-kDa translocator protein. There were no group differences in gray matter [3H]PK11195 binding, while binding was significantly greater in cocaine self-administration animals as compared to food controls in 8 of the 11 white matter tracts measured at the striatal level. Binding did not differ from control at other levels. There were also significant increases in white matter local cerebral glucose utilization at the striatal level, which were positively correlated with [3H]PK11195 binding. The present findings demonstrate an elevation in [3H]PK11195 binding in forebrain white matter tracts of nonhuman primates with a prolonged history of cocaine self-administration. These elevations were also associated with greater cerebral metabolic rates. These data suggest that white matter deficits may contribute to behavioral, motivational, and cognitive impairments observed in cocaine abusers.
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29
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Nack A, Brendel M, Nedelcu J, Daerr M, Nyamoya S, Beyer C, Focke C, Deussing M, Hoornaert C, Ponsaerts P, Schmitz C, Bartenstein P, Rominger A, Kipp M. Expression of Translocator Protein and [18F]-GE180 Ligand Uptake in Multiple Sclerosis Animal Models. Cells 2019; 8:cells8020094. [PMID: 30696113 PMCID: PMC6406715 DOI: 10.3390/cells8020094] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/16/2019] [Accepted: 01/23/2019] [Indexed: 12/19/2022] Open
Abstract
Positron emission tomography (PET) ligands targeting the translocator protein (TSPO) represent promising tools to visualize neuroinflammation in multiple sclerosis (MS). Although it is known that TSPO is expressed in the outer mitochondria membrane, its cellular localization in the central nervous system under physiological and pathological conditions is not entirely clear. The purpose of this study was to assess the feasibility of utilizing PET imaging with the TSPO tracer, [18F]-GE180, to detect histopathological changes during experimental demyelination, and to determine which cell types express TSPO. C57BL/6 mice were fed with cuprizone for up to 5 weeks to induce demyelination. Groups of mice were investigated by [18F]-GE180 PET imaging at week 5. Recruitment of peripheral immune cells was triggered by combining cuprizone intoxication with MOG35–55 immunization (i.e., Cup/EAE). Immunofluorescence double-labelling and transgene mice were used to determine which cell types express TSPO. [18F]-GE180-PET reliably detected the cuprizone-induced pathology in various white and grey matter regions, including the corpus callosum, cortex, hippocampus, thalamus and caudoputamen. Cuprizone-induced demyelination was paralleled by an increase in TSPO expression, glia activation and axonal injury. Most of the microglia and around one-third of the astrocytes expressed TSPO. TSPO expression induction was more severe in the white matter corpus callosum compared to the grey matter cortex. Although mitochondria accumulate at sites of focal axonal injury, these mitochondria do not express TSPO. In Cup/EAE mice, both microglia and recruited monocytes contribute to the TSPO expressing cell populations. These findings support the notion that TSPO is a valuable marker for the in vivo visualization and quantification of neuropathological changes in the MS brain. The pathological substrate of an increase in TSPO-ligand binding might be diverse including microglia activation, peripheral monocyte recruitment, or astrocytosis, but not axonal injury.
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MESH Headings
- Animals
- Astrocytes/pathology
- Astrocytes/ultrastructure
- Axons/metabolism
- Axons/ultrastructure
- Biomarkers/metabolism
- Carbazoles/metabolism
- Cuprizone
- Demyelinating Diseases/diagnostic imaging
- Demyelinating Diseases/pathology
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/diagnostic imaging
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Inflammation/pathology
- Ligands
- Mice, Inbred C57BL
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- Monocytes/metabolism
- Multiple Sclerosis/diagnostic imaging
- Neuroglia/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, GABA/genetics
- Receptors, GABA/metabolism
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Affiliation(s)
- Anne Nack
- Department of Anatomy II, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
- Department of Anatomy, 39071 Rostock University Medical Center, Rostock, Germany.
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Julia Nedelcu
- Department of Anatomy II, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
- Department of Anatomy, 39071 Rostock University Medical Center, Rostock, Germany.
| | - Markus Daerr
- Department of Anatomy II, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
- Department of Anatomy, 39071 Rostock University Medical Center, Rostock, Germany.
| | - Stella Nyamoya
- Department of Anatomy II, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
- Institute of Neuroanatomy, RWTH Aachen University, 52074 Aachen, Germany.
- Department of Anatomy, 39071 Rostock University Medical Center, Rostock, Germany.
| | - Cordian Beyer
- Institute of Neuroanatomy, RWTH Aachen University, 52074 Aachen, Germany.
| | - Carola Focke
- Department of Nuclear Medicine, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Maximilian Deussing
- Department of Nuclear Medicine, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Chloé Hoornaert
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium.
- Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium.
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium.
- Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium.
| | - Christoph Schmitz
- Department of Anatomy II, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany.
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Axel Rominger
- Department of Nuclear Medicine, University Hospital, LMU Munich, 80336 Munich, Germany.
- Department of Nuclear Medicine, Inselspital, University Hospital Bern, Bern, Switzerland.
| | - Markus Kipp
- Department of Anatomy, 39071 Rostock University Medical Center, Rostock, Germany.
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30
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Wang H, Zhu X, Xiang H, Liao Z, Gao M, Luo Y, Wu P, Zhang Y, Ren M, Zhao H, Xu M. Effects of altitude changes on mild-to-moderate closed-head injury in rats following acute high-altitude exposure. Exp Ther Med 2019; 17:847-856. [PMID: 30651871 DOI: 10.3892/etm.2018.7020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 10/12/2018] [Indexed: 11/05/2022] Open
Abstract
Mild-to-moderate closed-head injury (mmCHI) is an acute disease induced by high-altitudes. It is general practice to transfer patients to lower altitudes for treatment, but the pathophysiological changes at different altitudes following mmCHI remain unknown. The present study simulated acute high-altitude exposure (6,000 m above sea level) in rats to establish a model of mmCHI and recorded their vital signs. The rats were then randomly assigned into different altitude exposure groups (6,000, 4,500 and 3,000 m) and neurological severity score (NSS), body weight (BW), brain magnetic resonance imaging (MRI), brain water content (BWC) and the ratio of BW/BWC at 6, 12 and 24 h following mmCHI, and the glial fibrillary acidic protein levels were analysed in all groups. The results revealed that within the first 24 h following acute high-altitude exposure, mmCHI induced dehydration, brain oedema and neuronal damage. Brain injury in rats was significantly reversed following descent to 4,500 m compared with the results from 6,000 or 3,000 m. The results indicated that subjects should be transported as early as possible. Furthermore, avoiding large-span descent altitude was beneficial to reduce neurological impairment. The examination of brain-specific biomarkers and MRI may further be useful in determining the prognosis of high-altitude mmCHI. These results may provide guidance for rescuing high altitude injuries.
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Affiliation(s)
- Hao Wang
- Department of Neurosurgery, Daping Hospital, Third Military Medical University, Chongqing 400042, P.R. China
| | - Xiyan Zhu
- Chongqing Key Laboratory of Vehicle Crash/Bio-impact and Traffic Safety, Institute for Traffic Medicine, Third Military Medical University, Chongqing 400042, P.R. China
| | - Hongyi Xiang
- Chongqing Key Laboratory of Vehicle Crash/Bio-impact and Traffic Safety, Institute for Traffic Medicine, Third Military Medical University, Chongqing 400042, P.R. China
| | - Zhikang Liao
- Chongqing Key Laboratory of Vehicle Crash/Bio-impact and Traffic Safety, Institute for Traffic Medicine, Third Military Medical University, Chongqing 400042, P.R. China
| | - Mou Gao
- Affiliated Bayi Brain Hospital P.L.A Army General Hospital, Beijing 100038, P.R. China
| | - Yetao Luo
- School of Public Health and Management, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Pengfei Wu
- Department of Neurosurgery, Daping Hospital, Third Military Medical University, Chongqing 400042, P.R. China
| | - Yihua Zhang
- Department of Neurosurgery, Daping Hospital, Third Military Medical University, Chongqing 400042, P.R. China
| | - Mingliang Ren
- Department of Neurosurgery, Daping Hospital, Third Military Medical University, Chongqing 400042, P.R. China
| | - Hui Zhao
- Chongqing Key Laboratory of Vehicle Crash/Bio-impact and Traffic Safety, Institute for Traffic Medicine, Third Military Medical University, Chongqing 400042, P.R. China
| | - Minhui Xu
- Department of Neurosurgery, Daping Hospital, Third Military Medical University, Chongqing 400042, P.R. China
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31
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TSPO in diverse CNS pathologies and psychiatric disease: A critical review and a way forward. Pharmacol Ther 2018; 194:44-58. [PMID: 30189290 DOI: 10.1016/j.pharmthera.2018.09.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of Translocator Protein 18 kDa (TSPO) as a clinical neuroimaging biomarker of brain injury and neuroinflammation has increased exponentially in the last decade. There has been a furious pace in the development of new radiotracers for TSPO positron emission tomography (PET) imaging and its use has now been extensively described in many neurological and mental disorders. This fast pace of research and the ever-increasing number of new laboratories entering the field often times lack an appreciation of the historical perspective of the field and introduce dogmatic, but unproven facts, related to the underlying neurobiology of the TSPO response to brain injury and neuroinflammation. Paradoxically, while in neurodegenerative disorders and in all types of CNS pathologies brain TSPO levels increase, a new observation in psychiatric disorders such as schizophrenia is decreased brain levels of TSPO measured by PET. The neurobiological bases for this new finding is currently not known, but rigorous experimental design using multiple experimental approaches and careful interpretation of results is critically important to provide the methodological and/or biological underpinnings to this new observation. This review provides a perspective of the early history of validating TSPO as a biomarker of brain injury and neuroinflammation and a critical analysis of controversial topics in the literature related to the cellular sources of the TSPO response. The latter is important in order to provide the correct interpretation of PET studies in neurodegenerative and psychiatric disorders. Furthermore, this review proposes some yet to be explored explanations to new findings in psychiatric disorders and new approaches to quantitatively assess the glial sources of the TSPO response in order to move the field forward.
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32
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Saba W, Goutal S, Auvity S, Kuhnast B, Coulon C, Kouyoumdjian V, Buvat I, Leroy C, Tournier N. Imaging the neuroimmune response to alcohol exposure in adolescent baboons: a TSPO PET study using 18 F-DPA-714. Addict Biol 2018; 23:1000-1009. [PMID: 28944558 DOI: 10.1111/adb.12548] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/08/2017] [Accepted: 07/25/2017] [Indexed: 12/26/2022]
Abstract
The effects of acute alcohol exposure to the central nervous system are hypothesized to involve the innate immune system. The neuroimmune response to an initial and acute alcohol exposure was investigated using translocator protein 18 kDa (TSPO) PET imaging, a non-invasive marker of glial activation, in adolescent baboons. Three different alcohol-naive adolescent baboons (3-4 years old, 9 to 14 kg) underwent 18 F-DPA-714 PET experiments before, during and 7-12 months after this initial alcohol exposure (0.7-1.0 g/l). The brain distribution of 18 F-DPA-714 (VT ; in ml/cm3 ) was estimated in several brain regions using the Logan plot analysis and the metabolite-corrected arterial input function. Compared with alcohol-naive animals (VTbrain = 3.7 ± 0.7 ml/cm3 ), the regional VT s of 18 F-DPA-714 were significantly increased during alcohol exposure (VTbrain = 7.2 ± 0.4 ml/cm3 ; p < 0.001). Regional VT s estimated several months after alcohol exposure (VTbrain = 5.7 ± 1.4 ml/cm3 ) were lower (p < 0.001) than those measured during alcohol exposure, but remained significantly higher (p < 0.001) than in alcohol-naive animals. The acute and long-term effects of ethanol exposure were observed globally across all brain regions. Acute alcohol exposure increased the binding of 18 F-DPA-714 to the brain in a non-human primate model of alcohol exposure that reflects the 'binge drinking' situation in adolescent individuals. The effect persisted for several months, suggesting a 'priming' of glial cell function after initial alcohol exposure.
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Affiliation(s)
- Wadad Saba
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Sébastien Goutal
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Sylvain Auvity
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Bertrand Kuhnast
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Christine Coulon
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Virginie Kouyoumdjian
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Irène Buvat
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Claire Leroy
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
| | - Nicolas Tournier
- Imagerie Moléculaire In Vivo, IMIV, CEA, Inserm, CNRS; Univ. Paris-Sud, Université Paris Saclay, CEA-SHFJ; Orsay France
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33
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Kim SW, Wiers CE, Tyler R, Shokri-Kojori E, Jang YJ, Zehra A, Freeman C, Ramirez V, Lindgren E, Miller G, Cabrera EA, Stodden T, Guo M, Demiral ŞB, Diazgranados N, Park L, Liow JS, Pike V, Morse C, Vendruscolo LF, Innis RB, Koob GF, Tomasi D, Wang GJ, Volkow ND. Influence of alcoholism and cholesterol on TSPO binding in brain: PET [ 11C]PBR28 studies in humans and rodents. Neuropsychopharmacology 2018; 43:1832-1839. [PMID: 29777199 PMCID: PMC6046047 DOI: 10.1038/s41386-018-0085-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/02/2018] [Accepted: 04/20/2018] [Indexed: 01/08/2023]
Abstract
Neuroinflammation appears to contribute to neurotoxicity observed with heavy alcohol consumption. To assess whether chronic alcohol results in neuroinflammation we used PET and [11C]PBR28, a ligand that binds to the 18-kDa translocator protein (TSPO), to compare participants with an alcohol use disorder (AUD: n = 19) with healthy controls (HC: n = 17), and alcohol-dependent (n = 9) with -nondependent rats (n = 10). Because TSPO is implicated in cholesterol's transport for steroidogenesis, we investigated whether plasma cholesterol levels influenced [11C]PBR28 binding. [11C]PBR28 binding did not differ between AUD and HC. However, when separating by TSPO genotype rs6971, we showed that medium-affinity binders AUD participants showed lower [11C]PBR28 binding than HC in regions of interest (whole brain, gray and white matter, hippocampus, and thalamus), but no group differences were observed in high-affinity binders. Cholesterol levels inversely correlated with brain [11C]PBR28 binding in combined groups, due to a correlation in AUD participants. In rodents, we observed no differences in brain [11C]PBR28 uptake between alcohol-dependent and -nondependent rats. These findings, which are consistent with two previous [11C]PBR28 PET studies, may indicate lower activation of microglia in AUD, whereas failure to observe alcohol effects in the rodent model indicate that species differences do not explain the discrepancy with prior rodent autoradiographic studies reporting increases in TSPO binding with chronic alcohol. However, reduced binding in AUD participants could also reflect competition from endogenous TSPO ligands such as cholesterol; and since the rs6971 polymorphism affects the cholesterol-binding domain of TSPO this could explain why differences were observed only in medium-affinity binders.
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Affiliation(s)
- Sung Won Kim
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Corinde E. Wiers
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Ryan Tyler
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Ehsan Shokri-Kojori
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Yeon Joo Jang
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Amna Zehra
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Clara Freeman
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Veronica Ramirez
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Elsa Lindgren
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Gregg Miller
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Elizabeth A. Cabrera
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Tyler Stodden
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Min Guo
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Şükrü B. Demiral
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Nancy Diazgranados
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Luke Park
- 0000 0001 2297 5165grid.94365.3dMolecular Imaging Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892 USA
| | - Jeih-San Liow
- 0000 0001 2297 5165grid.94365.3dMolecular Imaging Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892 USA
| | - Victor Pike
- 0000 0001 2297 5165grid.94365.3dMolecular Imaging Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892 USA
| | - Cheryl Morse
- 0000 0001 2297 5165grid.94365.3dMolecular Imaging Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892 USA
| | - Leandro F. Vendruscolo
- 0000 0000 9372 4913grid.419475.aNational Institute on Drug Abuse, NIH, Baltimore, MD 21224 USA
| | - Robert B. Innis
- 0000 0001 2297 5165grid.94365.3dMolecular Imaging Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892 USA
| | - George F. Koob
- 0000 0000 9372 4913grid.419475.aNational Institute on Drug Abuse, NIH, Baltimore, MD 21224 USA
| | - Dardo Tomasi
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Gene-Jack Wang
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
| | - Nora D. Volkow
- 0000 0001 2297 5165grid.94365.3dNational Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892 USA
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Bonsack F, Sukumari-Ramesh S. TSPO: An Evolutionarily Conserved Protein with Elusive Functions. Int J Mol Sci 2018; 19:ijms19061694. [PMID: 29875327 PMCID: PMC6032217 DOI: 10.3390/ijms19061694] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 12/22/2022] Open
Abstract
TSPO (18 kDa translocator protein) was identified decades ago in a search for peripheral tissue binding sites for benzodiazepines, and was formerly called the peripheral benzodiazepine receptor. TSPO is a conserved protein throughout evolution and it is implicated in the regulation of many cellular processes, including inflammatory responses, oxidative stress, and mitochondrial homeostasis. TSPO, apart from its broad expression in peripheral tissues, is highly expressed in neuroinflammatory cells, such as activated microglia. In addition, emerging studies employing the ligands of TSPO suggest that TSPO plays an important role in neuropathological settings as a biomarker and therapeutic target. However, the precise molecular function of this protein in normal physiology and neuropathology remains enigmatic. This review provides an overview of recent advances in our understanding of this multifaceted molecule and identifies the knowledge gap in the field for future functional studies.
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Affiliation(s)
- Frederick Bonsack
- Department of Neurosurgery, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
| | - Sangeetha Sukumari-Ramesh
- Department of Neurosurgery, Medical College of Georgia, Augusta University, 1120 15th Street, Augusta, GA 30912, USA.
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35
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Vargas-Sánchez K, Mogilevskaya M, Rodríguez-Pérez J, Rubiano MG, Javela JJ, González-Reyes RE. Astroglial role in the pathophysiology of status epilepticus: an overview. Oncotarget 2018; 9:26954-26976. [PMID: 29928494 PMCID: PMC6003549 DOI: 10.18632/oncotarget.25485] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/09/2018] [Indexed: 12/11/2022] Open
Abstract
Status epilepticus is a medical emergency with elevated morbidity and mortality rates, and represents a leading cause of epilepsy-related deaths. Though status epilepticus can occur at any age, it manifests more likely in children and elderly people. Despite the common prevalence of epileptic disorders, a complete explanation for the mechanisms leading to development of self-limited or long lasting seizures (as in status epilepticus) are still lacking. Apart from neurons, research evidence suggests the involvement of immune and glial cells in epileptogenesis. Among glial cells, astrocytes represent an ideal target for the study of the pathophysiology of status epilepticus, due to their key role in homeostatic balance of the central nervous system. During status epilepticus, astroglial cells are activated by the presence of cytokines, damage associated molecular patterns and reactive oxygen species. The persistent activation of astrocytes leads to a decrease in glutamate clearance with a corresponding accumulation in the synaptic extracellular space, increasing the chance of neuronal excitotoxicity. Moreover, major alterations in astrocytic gap junction coupling, inflammation and receptor expression, facilitate the generation of seizures. Astrocytes are also involved in dysregulation of inhibitory transmission in the central nervous system and directly participate in ionic homeostatic alterations during status epilepticus. In the present review, we focus on the functional and structural changes in astrocytic activity that participate in the development and maintenance of status epilepticus, with special attention on concurrent inflammatory alterations. We also include potential astrocytic treatment targets for status epilepticus.
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Affiliation(s)
- Karina Vargas-Sánchez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | | | - John Rodríguez-Pérez
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - María G Rubiano
- Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - José J Javela
- Grupo de Clínica y Salud Mental, Programa de Psicología, Universidad Católica de Pereira, Pereira, Colombia
| | - Rodrigo E González-Reyes
- Universidad del Rosario, Escuela de Medicina y Ciencias de la Salud, GI en Neurociencias-NeURos, Bogotá, Colombia
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36
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Airas L, Nylund M, Rissanen E. Evaluation of Microglial Activation in Multiple Sclerosis Patients Using Positron Emission Tomography. Front Neurol 2018; 9:181. [PMID: 29632509 PMCID: PMC5879102 DOI: 10.3389/fneur.2018.00181] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/08/2018] [Indexed: 01/24/2023] Open
Abstract
Understanding the mechanisms underlying progression in multiple sclerosis (MS) is one of the key elements contributing to the identification of appropriate therapeutic targets for this under-managed condition. In addition to plaque-related focal inflammatory pathology typical for relapsing remitting MS there are, in progressive MS, widespread diffuse alterations in brain areas outside the focal lesions. This diffuse pathology is tightly related to microglial activation and is co-localized with signs of neurodegeneration. Microglia are brain-resident cells of the innate immune system and overactivation of microglia is associated with several neurodegenerative diseases. Understanding the role of microglial activation in relation to developing neurodegeneration and disease progression may provide a key to developing therapies to target progressive MS. 18-kDa translocator protein (TSPO) is a mitochondrial molecule upregulated in microglia upon their activation. Positron emission tomography (PET) imaging using TSPO-binding radioligands provides a method to assess microglial activation in patients in vivo. In this mini-review, we summarize the current status of TSPO imaging in the field of MS. In addition, the review discusses new insights into the potential use of this method in treatment trials and in clinical assessment of progressive MS.
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Affiliation(s)
- Laura Airas
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Marjo Nylund
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland.,Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
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Abstract
Positron-emission tomography (PET) imaging is a valuable research tool that enables in vivo quantification of molecular targets in the brain or of a physiologic process. PET imaging can be combined with various experimental and clinical model systems that are commonly used in psychoneuroimmunology research. As PET imaging can be used in animals and humans, promising results can therefore often be translated from an animal model to human disease.
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Cheng Q, Sun GJ, Liu SB, Yang Q, Li XM, Li XB, Liu G, Zhao JN, Zhao MG. A novel translocator protein 18 kDa ligand, ZBD-2, exerts neuroprotective effects against acute spinal cord injury. Clin Exp Pharmacol Physiol 2017; 43:930-8. [PMID: 27292096 DOI: 10.1111/1440-1681.12606] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/26/2016] [Accepted: 06/09/2016] [Indexed: 12/27/2022]
Abstract
Traumatic spinal cord injury (SCI) happens accidently and often leads to motor dysfunction due to a series of biochemical and pathological events and damage, either temporarily or permanently. Translocator protein 18 (TSPO) has been found to be involved in the synthesis of endogenous neurosteroids which have multiple effects on neurons, but the internal mechanisms are not clear. N-benzyl-N-ethyl-2-(7,8-oxo-2-phenyl-9H-purin-9-yl) acetamide (ZBD-2), a newly reported ligand of TSPO, shows some neuroprotective effect against focal cerebral ischemia in vivo and NMDA-induced neurotoxicity in vitro. The present study aims to examine the role of ZBD-2 in SCI mice and elucidate the underlying molecular mechanisms. The SCI model was established by crushing spinal cord. ZBD-2 (10 mg/kg) significantly enhanced the hindlimb locomotor functions after SCI and decreased the tissue damage and conserved the white matter of the spinal cord. High-dose ZBD-2 alleviated the oxidative stress induced by SCI and regulated the imbalance between NR2B-containing NMDA and GABA receptors by increasing the levels of GAD67 in the spinal cord of SCI mice. Additionally, ZBD-2 (10 mg/kg) increased phosphorylated Akt (p-Akt) and decreased the ratio of Bax/Bcl-2. These results demonstrate that ZBD-2 performs neuroprotection against SCI through regulating the synaptic transmission and the PI3K/AKT signaling pathway.
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Affiliation(s)
- Qiang Cheng
- Department of Orthopedics, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing, China
| | - Guo-Jing Sun
- Department of Orthopedics, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Qi Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Xiao-Ming Li
- Department of Orthopedics, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing, China
| | - Xu-Bo Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Gang Liu
- Department of Orthopedics, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing, China
| | - Jian-Ning Zhao
- Department of Orthopedics, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing, China
| | - Ming-Gao Zhao
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
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Dupont AC, Largeau B, Santiago Ribeiro MJ, Guilloteau D, Tronel C, Arlicot N. Translocator Protein-18 kDa (TSPO) Positron Emission Tomography (PET) Imaging and Its Clinical Impact in Neurodegenerative Diseases. Int J Mol Sci 2017; 18:ijms18040785. [PMID: 28387722 PMCID: PMC5412369 DOI: 10.3390/ijms18040785] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
In vivo exploration of activated microglia in neurodegenerative diseases is achievable by Positron Emission Tomography (PET) imaging, using dedicated radiopharmaceuticals targeting the translocator protein-18 kDa (TSPO). In this review, we emphasized the major advances made over the last 20 years, thanks to TSPO PET imaging, to define the pathophysiological implication of microglia activation and neuroinflammation in neurodegenerative diseases, including Parkinson’s disease, Huntington’s disease, dementia, amyotrophic lateral sclerosis, multiple sclerosis, and also in psychiatric disorders. The extent and upregulation of TSPO as a molecular biomarker of activated microglia in the human brain is now widely documented in these pathologies, but its significance, and especially its protective or deleterious action regarding the disease’s stage, remains under debate. Thus, we exposed new and plausible suggestions to enhance the contribution of TSPO PET imaging for biomedical research by exploring microglia’s role and interactions with other cells in brain parenchyma. Multiplex approaches, associating TSPO PET radiopharmaceuticals with other biomarkers (PET imaging of cellular metabolism, neurotransmission or abnormal protein aggregates, but also other imaging modalities, and peripheral cytokine levels measurement and/or metabolomics analysis) was considered. Finally, the actual clinical impact of TSPO PET imaging as a routine biomarker of neuroinflammation was put into perspective regarding the current development of diagnostic and therapeutic strategies for neurodegenerative diseases.
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Affiliation(s)
- Anne-Claire Dupont
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | | | - Maria Joao Santiago Ribeiro
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Denis Guilloteau
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Claire Tronel
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
| | - Nicolas Arlicot
- CHRU Tours, 2 Boulevard Tonnellé, 37044 Tours, France.
- Institut National de la Santé et de la Recherche Médicale U930, 10 Boulevard Tonnellé, 37032 Tours, France.
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40
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Volk DW. Role of microglia disturbances and immune-related marker abnormalities in cortical circuitry dysfunction in schizophrenia. Neurobiol Dis 2016; 99:58-65. [PMID: 28007586 DOI: 10.1016/j.nbd.2016.12.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 11/14/2016] [Accepted: 12/18/2016] [Indexed: 11/19/2022] Open
Abstract
Studies of genetics, serum cytokines, and autoimmune illnesses suggest that immune-related abnormalities are involved in the disease process of schizophrenia. Furthermore, direct evidence of cortical immune activation, including markedly elevated levels of many immune-related markers, have been reported in the prefrontal cortex in multiple cohorts of schizophrenia subjects. Within the prefrontal cortex in schizophrenia, deficits in the basilar dendritic spines of layer 3 pyramidal neurons and disturbances in inhibitory inputs to pyramidal neurons have also been commonly reported. Interestingly, microglia, the resident immune-related cells of the brain, also regulate excitatory and inhibitory input to pyramidal neurons. Consequently, in this review, we describe the cytological and molecular evidence of immune activation that has been reported in the brains of individuals with schizophrenia and the potential links between these immune-related disturbances with previously reported disturbances in pyramidal and inhibitory neurons in the disorder. Finally, we discuss the role that activated microglia may play in connecting these observations and as potential therapeutic treatment targets in schizophrenia.
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Affiliation(s)
- David W Volk
- Department of Psychiatry, University of Pittsburgh, W1655 BST, 3811 O'Hara St, Pittsburgh, PA 15213, United States.
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41
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Sokias R, Werry EL, Chua SW, Reekie TA, Munoz L, Wong ECN, Ittner LM, Kassiou M. Determination and reduction of translocator protein (TSPO) ligand rs6971 discrimination. MEDCHEMCOMM 2016; 8:202-210. [PMID: 30108706 PMCID: PMC6071920 DOI: 10.1039/c6md00523c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/11/2016] [Indexed: 12/26/2022]
Abstract
The 18 kDa translocator protein (TSPO) is a target for development of diagnostic imaging agents for glioblastoma and neuroinflammation.
The 18 kDa translocator protein (TSPO) is a target for development of diagnostic imaging agents for glioblastoma and neuroinflammation. Clinical translation of TSPO imaging agents has been hindered by the presence of a polymorphism, rs6971, which causes a non-conservative substitution of alanine for threonine at amino acid residue 147 (TSPO A147T). Disclosed brain-permeant second-generation TSPO ligands bind TSPO A147T with reduced affinity compared to the wild type protein (TSPO WT). Efforts to develop a TSPO ligand that binds TSPO WT and TSPO A147T with similarly high affinity have been hampered by a lack of knowledge about how ligand structure differentially influences interaction with the two forms of TSPO. To gain insight, we have established human embryonic kidney cell lines stably over-expressing human TSPO WT and TSPO A147T, and tested how modifications of a novel N-alkylated carbazole scaffold influence affinity to both TSPO isoforms. Most of the new analogues developed in this study showed high affinity to TSPO WT and a 5–6-fold lower affinity to TSPO A147T. Addition of electron-withdrawing substituents yielded analogues with highest affinity for TSPO A147T without decreasing affinity for TSPO WT. This knowledge can be used to inform further development of non-discriminating TSPO ligands for use as diagnostic markers for glioblastoma and neuroinflammation irrespective of rs6971.
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Affiliation(s)
- Renee Sokias
- School of Chemistry , The University of Sydney , NSW 2006 , Australia .
| | - Eryn L Werry
- Faculty of Health Sciences , The University of Sydney , NSW 2006 , Australia.,School of Medical Sciences (Pharmacology) , Bosch Institute , The University of Sydney , NSW 2006 , Australia
| | - Sook W Chua
- Dementia Research Unit , School of Medical Sciences , University of New South Wales , NSW 2052 , Australia
| | - Tristan A Reekie
- School of Chemistry , The University of Sydney , NSW 2006 , Australia .
| | - Lenka Munoz
- School of Medical Sciences (Pathology) and Charles Perkins Centre , The University of Sydney , NSW 2006 , Australia
| | - Erick C N Wong
- School of Medical Sciences (Pharmacology) , Bosch Institute , The University of Sydney , NSW 2006 , Australia
| | - Lars M Ittner
- Dementia Research Unit , School of Medical Sciences , University of New South Wales , NSW 2052 , Australia
| | - Michael Kassiou
- School of Chemistry , The University of Sydney , NSW 2006 , Australia .
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Evaluation of PET Imaging Performance of the TSPO Radioligand [18F]DPA-714 in Mouse and Rat Models of Cancer and Inflammation. Mol Imaging Biol 2016; 18:127-34. [PMID: 26194010 PMCID: PMC4722075 DOI: 10.1007/s11307-015-0877-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Purpose Many radioligands have been explored for imaging the 18-kDa translocator protein (TSPO), a diagnostic and therapeutic target for inflammation and cancer. Here, we investigated the TSPO radioligand [18F]DPA-714 for positron emission tomography (PET) imaging of cancer and inflammation. Procedures [18F]DPA-714 PET imaging was performed in 8 mouse and rat models of breast and brain cancer and 4 mouse and rat models of muscular and bowel inflammation. Results [18F]DPA-714 showed different uptake levels in healthy organs and malignant tissues of mice and rats. Although high and displaceable [18F]DPA-714 binding is observed ex vivo, TSPO-positive PET imaging of peripheral lesions of cancer and inflammation in mice did not show significant lesion-to-background signal ratios. Slower [18F]DPA-714 metabolism and muscle clearance in mice compared to rats may explain the elevated background signal in peripheral organs in this species. Conclusion Although TSPO is an evolutionary conserved protein, inter- and intra-species differences call for further exploration of the pharmacological parameters of TSPO radioligands. Electronic supplementary material The online version of this article (doi:10.1007/s11307-015-0877-x) contains supplementary material, which is available to authorized users.
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43
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Multitasking Microglia and Alzheimer's Disease: Diversity, Tools and Therapeutic Targets. J Mol Neurosci 2016; 60:390-404. [PMID: 27660215 DOI: 10.1007/s12031-016-0825-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 08/17/2016] [Indexed: 01/08/2023]
Abstract
Given the importance of microglia to inflammatory, phagocytic and synaptic modulatory processes, their function is vital in physiological and pathological brain. The impairment of microglia in Alzheimer's disease has been demonstrated on genetic, epigenetic, transcriptional and functional levels using unbiased systems level approaches. Recent studies have highlighted the immense phenotypic diversity of microglia, including the ability to adopt distinct and dynamic phenotypes in ageing and disease. We review the origins and functions of healthy microglia and the established and emerging models and techniques available for their study. Furthermore, we highlight recent advances on the role, heterogeneity and dysfunction of microglia in Alzheimer's disease and discuss the potential for therapeutic interventions targeting microglia. Microglia-selective molecular fingerprints will guide detailed functional analysis of microglial subsets and may aid in the development of therapies specifically targeting microglia.
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Simon-O'Brien E, Gauthier D, Riban V, Verleye M. Etifoxine improves sensorimotor deficits and reduces glial activation, neuronal degeneration, and neuroinflammation in a rat model of traumatic brain injury. J Neuroinflammation 2016; 13:203. [PMID: 27565146 PMCID: PMC5002207 DOI: 10.1186/s12974-016-0687-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 08/18/2016] [Indexed: 12/14/2022] Open
Abstract
Background Traumatic brain injury (TBI) results in important neurological impairments which occur through a cascade of deleterious physiological events over time. There are currently no effective treatments to prevent these consequences. TBI is followed not only by an inflammatory response but also by a profound reorganization of the GABAergic system and a dysregulation of translocator protein 18 kDa (TSPO). Etifoxine is an anxiolytic compound that belongs to the benzoxazine family. It potentiates GABAergic neurotransmission, either through a positive allosteric effect or indirectly, involving the activation of TSPO that leads to an increase in neurosteroids synthesis. In several models of peripheral nerve injury, etifoxine has been demonstrated to display potent regenerative and anti-inflammatory properties and to promote functional recovery. Prior study also showed etifoxine efficacy in reducing brain edema in rats. In light of these positive results, we used a rat model of TBI to explore etifoxine treatment effects in a central nervous system injury, from functional outcomes to the underlying mechanisms. Methods Male Sprague-Dawley rats received contusion (n = 18) or sham (n = 19) injuries centered laterally to bregma over the left sensorimotor cortex. They were treated with etifoxine (50 mg/kg, i.p.) or its vehicle 30 min following injury and every day during 7 days. Rats underwent behavioral testing to assess sensorimotor function. In another experiment, injured rats (n = 10) or sham rats (n = 10) received etifoxine (EFX) (50 mg/kg, i.p.) or its vehicle 30 min post-surgery. Brains were then dissected for analysis of neuroinflammation markers, glial activation, and neuronal degeneration. Results Brain-injured rats exhibited significant sensorimotor function deficits compared to sham-injured rats in the bilateral tactile adhesive removal test, the beam walking test, and the limb-use asymmetry test. After 2 days of etifoxine treatment, behavioral impairments were significantly reduced. Etifoxine treatment reduced pro-inflammatory cytokines levels without affecting anti-inflammatory cytokines levels in injured rats, reduced macrophages and glial activation, and reduced neuronal degeneration. Conclusions Our results showed that post-injury treatment with etifoxine improved functional recovery and reduced neuroinflammation in a rat model of TBI. These findings suggest that etifoxine may have a therapeutic potential in the treatment of TBI.
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Affiliation(s)
| | - Delphine Gauthier
- Pharmacology Department, Biocodex, Chemin d'Armancourt, 60200, Compiègne, France
| | - Véronique Riban
- Pharmacology Department, Biocodex, Chemin d'Armancourt, 60200, Compiègne, France
| | - Marc Verleye
- Pharmacology Department, Biocodex, Chemin d'Armancourt, 60200, Compiègne, France
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45
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Augmented expression of TSPO after intracerebral hemorrhage: a role in inflammation? J Neuroinflammation 2016; 13:151. [PMID: 27315802 PMCID: PMC4912814 DOI: 10.1186/s12974-016-0619-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/09/2016] [Indexed: 02/08/2023] Open
Abstract
Background Intracerebral hemorrhage (ICH) is a potentially fatal stroke subtype accounting for 10–15 % of all strokes. Despite neurosurgical intervention and supportive care, the 30-day mortality rate remains 30–50 % with ICH survivors frequently displaying neurological impairment and requiring long-term assisted care. Although accumulating evidence demonstrates the role of neuroinflammation in secondary brain injury and delayed fatality after ICH, the molecular regulators of neuroinflammation remain poorly defined after ICH. Methods In the present study, ICH was induced in CD1 male mice by collagenase injection method and given the emerging role of TSPO (18-kDa translocator protein) in neuroinflammation, immunofluorescence staining of brain sections was performed to characterize the temporal expression pattern and cellular and subcellular localization of TSPO after ICH. Further, both genetic and pharmacological studies were employed to assess the functional role of TSPO in neuroinflammation. Results The expression of TSPO was found to be increased in the peri-hematomal brain region 1 to 7 days post-injury, peaking on day 3 to day 5 in comparison to sham. Further, the TSPO expression was mostly observed in microglia/macrophages, the inflammatory cells of the central nervous system, suggesting an unexplored role of TSPO in neuroinflammatory responses after ICH. Further, the subcellular localization studies revealed prominent perinuclear expression of TSPO after ICH. Moreover, both genetic and pharmacological studies revealed a regulatory role of TSPO in the release of pro-inflammatory cytokines in a macrophage cell line, RAW 264.7. Conclusions Altogether, the data suggest that TSPO induction after ICH could be an intrinsic mechanism to prevent an exacerbated inflammatory response and raise the possibility of targeting TSPO for the attenuation of secondary brain injury after ICH.
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Li F, Liu J, Liu N, Kuhn LA, Garavito RM, Ferguson-Miller S. Translocator Protein 18 kDa (TSPO): An Old Protein with New Functions? Biochemistry 2016; 55:2821-31. [PMID: 27074410 DOI: 10.1021/acs.biochem.6b00142] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translocator protein 18 kDa (TSPO) was previously known as the peripheral benzodiazepine receptor (PBR) in eukaryotes, where it is mainly localized to the mitochondrial outer membrane. Considerable evidence indicates that it plays regulatory roles in steroidogenesis and apoptosis and is involved in various human diseases, such as metastatic cancer, Alzheimer's and Parkinson's disease, inflammation, and anxiety disorders. Ligands of TSPO are widely used as diagnostic tools and treatment options, despite there being no clear understanding of the function of TSPO. An ortholog in the photosynthetic bacterium Rhodobacter was independently discovered as the tryptophan-rich sensory protein (TspO) and found to play a role in the response to changes in oxygen and light conditions that regulate photosynthesis and respiration. As part of this highly conserved protein family found in all three kingdoms, the rat TSPO is able to rescue the knockout phenotype in Rhodobacter, indicating functional as well as structural conservation. Recently, a major breakthrough in the field was achieved: the determination of atomic-resolution structures of TSPO from different species by several independent groups. This now allows us to reexamine the function of TSPO with a molecular perspective. In this review, we focus on recently determined structures of TSPO and their implications for potential functions of this ubiquitous multifaceted protein. We suggest that TSPO is an ancient bacterial receptor/stress sensor that has developed additional interactions, partners, and roles in its mitochondrial outer membrane environment in eukaryotes.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Nan Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States.,Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - Leslie A Kuhn
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
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47
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Guilarte TR, Loth MK, Guariglia SR. TSPO Finds NOX2 in Microglia for Redox Homeostasis. Trends Pharmacol Sci 2016; 37:334-343. [PMID: 27113160 DOI: 10.1016/j.tips.2016.02.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/22/2016] [Accepted: 02/25/2016] [Indexed: 10/21/2022]
Abstract
During the past decade, translocator protein 18 kDa (TSPO), previously named peripheral benzodiazepine receptor, has gained a great deal of attention based on its use as a clinical biomarker of neuroinflammation with therapeutic potential. However, there is a paucity of knowledge on the function(s) of TSPO in glial cells. Here, we identify a novel function of TSPO in microglia that is not associated with steroidogenesis. We propose that a TSPO interaction with NADPH oxidase (NOX2) links the generation of reactive oxygen species (ROS) to the induction of an antioxidant response to maintain redox homeostasis. This line of investigation may provide a greater understanding of TSPO glial cell biology, and the knowledge gained may prove beneficial in devising therapeutic strategies.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA.
| | - Meredith K Loth
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Sara R Guariglia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
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Santoro A, Mattace Raso G, Taliani S, Da Pozzo E, Simorini F, Costa B, Martini C, Laneri S, Sacchi A, Cosimelli B, Calignano A, Da Settimo F, Meli R. TSPO-ligands prevent oxidative damage and inflammatory response in C6 glioma cells by neurosteroid synthesis. Eur J Pharm Sci 2016; 88:124-31. [PMID: 27094781 DOI: 10.1016/j.ejps.2016.04.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 11/30/2022]
Abstract
Translocator protein 18kDa (TSPO) is predominantly located in the mitochondrial outer membrane, playing an important role in steroidogenesis, inflammation, cell survival and proliferation. Its expression in central nervous system, mainly in glial cells, has been found to be upregulated in neuropathology, and brain injury. In this study, we investigated the anti-oxidative and anti-inflammatory effects of a group of TSPO ligands from the N,N-dialkyl-2-phenylindol-3-ylglyoxylamide class (PIGAs), highlighting the involvement of neurosteroids in their pharmacological effects. To this aim we used a well-known in vitro model of neurosteroidogenesis: the astrocytic C6 glioma cell line, where TSPO expression and localization, as well as cell response to TSPO ligand treatment, have been established. All PIGAs reduced l-buthionine-(S,R)-sulfoximine (BSO)-driven cell cytotoxicity and lipid peroxidation. Moreover, an anti-inflammatory effect was observed due to the reduction of inducible nitric oxide synthase and cyclooxygenase-2 induction in LPS/IFNγ challenged cells. Both effects were blunted by aminoglutethimide (AMG), an inhibitor of pregnenolone synthesis, suggesting neurosteroids' involvement in PIGA protective mechanism. Finally, pregnenolone evaluation in PIGA exposed cells revealed an increase in its synthesis, which was prevented by AMG pre-treatment. These findings indicate that these TSPO ligands reduce oxidative stress and pro-inflammatory enzymes in glial cells through the de novo synthesis of neurosteroids, suggesting that these compounds could be potential new therapeutic tools for the treatment of inflammatory-based neuropathologies with beneficial effects possibly comparable to steroids, but potentially avoiding the negative side effects of long-term therapies with steroid hormones.
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Affiliation(s)
- Anna Santoro
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | - Giuseppina Mattace Raso
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | | | | | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Sonia Laneri
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | - Antonia Sacchi
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | - Barbara Cosimelli
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | - Antonio Calignano
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy
| | | | - Rosaria Meli
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
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Femminella GD, Ninan S, Atkinson R, Fan Z, Brooks DJ, Edison P. Does Microglial Activation Influence Hippocampal Volume and Neuronal Function in Alzheimer’s Disease and Parkinson’s Disease Dementia? J Alzheimers Dis 2016; 51:1275-89. [DOI: 10.3233/jad-150827] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | | | | | - Zhen Fan
- Neurology Imaging Unit, Imperial College London, London, UK
| | - David J. Brooks
- Neurology Imaging Unit, Imperial College London, London, UK
- Department of Nuclear Medicine, Aarhus University, Denmark
| | - Paul Edison
- Neurology Imaging Unit, Imperial College London, London, UK
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Changes in Binding of [(123)I]CLINDE, a High-Affinity Translocator Protein 18 kDa (TSPO) Selective Radioligand in a Rat Model of Traumatic Brain Injury. Neuromolecular Med 2016; 18:158-69. [PMID: 26969181 DOI: 10.1007/s12017-016-8385-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/02/2016] [Indexed: 01/01/2023]
Abstract
After traumatic brain injury (TBI), secondary injuries develop, including neuroinflammatory processes that contribute to long-lasting impairments. These secondary injuries represent potential targets for treatment and diagnostics. The translocator protein 18 kDa (TSPO) is expressed in activated microglia cells and upregulated in response to brain injury and therefore a potential biomarker of the neuroinflammatory processes. Second-generation radioligands of TSPO, such as [(123)I]CLINDE, have a higher signal-to-noise ratio as the prototype ligand PK11195. [(123)I]CLINDE has been employed in human studies using single-photon emission computed tomography to image the neuroinflammatory response after stroke. In this study, we used the same tracer in a rat model of TBI to determine changes in TSPO expression. Adult Sprague-Dawley rats were subjected to moderate controlled cortical impact injury and sacrificed at 6, 24, 72 h and 28 days post surgery. TSPO expression was assessed in brain sections employing [(123)I]CLINDE in vitro autoradiography. From 24 h to 28 days post surgery, injured animals exhibited a marked and time-dependent increase in [(123)I]CLINDE binding in the ipsilateral motor, somatosensory and parietal cortex, as well as in the hippocampus and thalamus. Interestingly, binding was also significantly elevated in the contralateral M1 motor cortex following TBI. Craniotomy without TBI caused a less marked increase in [(123)I]CLINDE binding, restricted to the ipsilateral hemisphere. Radioligand binding was consistent with an increase in TSPO mRNA expression and CD11b immunoreactivity at the contusion site. This study demonstrates the applicability of [(123)I]CLINDE for detailed regional and quantitative assessment of glial activity in experimental models of TBI.
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