1
|
Liao K, Chen JH, Ma J, Dong CC, Bi CY, Gao YB, Jiang YF, Wang T, Wei HY, Hou L, Hu JQ, Wei JJ, Zeng CY, Li YL, Yan S, Xu H, Liang SH, Wang L. Preclinical characterization of [ 18F]D 2-LW223: an improved metabolically stable PET tracer for imaging the translocator protein 18 kDa (TSPO) in neuroinflammatory rodent models and non-human primates. Acta Pharmacol Sin 2024:10.1038/s41401-024-01375-9. [PMID: 39210042 DOI: 10.1038/s41401-024-01375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Accepted: 07/31/2024] [Indexed: 09/04/2024] Open
Abstract
Positron emission tomography (PET) targeting translocator protein 18 kDa (TSPO) can be used for the noninvasive detection of neuroinflammation. Improved in vivo stability of a TSPO tracer is beneficial for minimizing the potential confounding effects of radiometabolites. Deuteration represents an important strategy for improving the pharmacokinetics and stability of existing drug molecules in the plasma. This study developed a novel tracer via the deuteration of [18F]LW223 and evaluated its in vivo stability and specific binding in neuroinflammatory rodent models and nonhuman primate (NHP) brains. Compared with LW223, D2-LW223 exhibited improved binding affinity to TSPO. Compared with [18F]LW223, [18F]D2-LW223 has superior physicochemical properties and favorable brain kinetics, with enhanced metabolic stability and reduced defluorination. Preclinical investigations in rodent models of LPS-induced neuroinflammation and cerebral ischemia revealed specific [18F]D2-LW223 binding to TSPO in regions affected by neuroinflammation. Two-tissue compartment model analyses provided excellent model fits and allowed the quantitative mapping of TSPO across the NHP brain. These results indicate that [18F]D2-LW223 holds significant promise for the precise quantification of TSPO expression in neuroinflammatory pathologies of the brain.
Collapse
Affiliation(s)
- Kai Liao
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jia-Hui Chen
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Jie Ma
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chen-Chen Dong
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chun-Yang Bi
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Ya-Biao Gao
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Yuan-Fang Jiang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Tao Wang
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, 510632, China
| | - Hui-Yi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Lu Hou
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jun-Qi Hu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Jun-Jie Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Chun-Yuan Zeng
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China
| | - Yin-Long Li
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA
| | - Sen Yan
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou, 510632, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China.
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA.
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine & Key laboratory of Basic and Translational Research on Radiopharmaceuticals, The First Affiliated Hospital of Jinan University, Guangzhou, 510630, China.
- Guangzhou Key Laboratory of Basic and Translational Research on Chronic Disease, Guangzhou, 510630, China.
| |
Collapse
|
2
|
Garbizu M, Aguado L, Martín A. Alpha7 nicotinic receptors as potential theranostic targets for experimental stroke. Neural Regen Res 2024; 19:939-940. [PMID: 37862178 PMCID: PMC10749633 DOI: 10.4103/1673-5374.385294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 10/22/2023] Open
Affiliation(s)
- Maider Garbizu
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Laura Aguado
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Ikerbasque Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
3
|
Cipriani R, Domerq M, Martín A, Matute C. Role of Microglia in Stroke. ADVANCES IN NEUROBIOLOGY 2024; 37:405-422. [PMID: 39207705 DOI: 10.1007/978-3-031-55529-9_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Ischemic stroke is a complex brain pathology caused by an interruption of blood supply to the brain. It results in neurological deficits which that reflect the localization and the size of the compromised brain area and are the manifestation of complex pathogenic events triggered by energy depletion. Inflammation plays a prominent role, worsening the injury in the early phase and influencing poststroke recovery in the late phase. Activated microglia are one of the most important cellular components of poststroke inflammation, appearing from the first few hours and persisting for days and weeks after stroke injury. In this chapter, we will discuss the nature of the inflammatory response in brain ischemia, the contribution of microglia to injury and regeneration after stroke, and finally, how ischemic stroke directly affects microglia functions and survival.
Collapse
Affiliation(s)
| | - Maria Domerq
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- Ikerbasque Basque Foundation for Science, Bilbao, Spain.
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU) and CIBERNED, Leioa, Spain.
| |
Collapse
|
4
|
Mahemuti Y, Kadeer K, Su R, Abula A, Aili Y, Maimaiti A, Abulaiti S, Maimaitituerxun M, Miao T, Jiang S, Axier A, Aisha M, Wang Y, Cheng X. TSPO exacerbates acute cerebral ischemia/reperfusion injury by inducing autophagy dysfunction. Exp Neurol 2023; 369:114542. [PMID: 37717810 DOI: 10.1016/j.expneurol.2023.114542] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Autophagy is considered a double-edged sword, with a role in the regulation of the pathophysiological processes of the central nervous system (CNS) after cerebral ischemia-reperfusion injury (CIRI). The 18-kDa translocator protein (TSPO) is a highly conserved protein, with its expression level in the nervous system closely associated with the regulation of pathophysiological processes. In addition, the ligand of TSPO reduces neuroinflammation in brain diseases, but the potential role of TSPO in CIRI is largely undiscovered. On this basis, we investigated whether TSPO regulates neuroinflammatory response by affecting autophagy in microglia. In our study, increased expression of TSPO was detected in rat brain tissues with transient middle cerebral artery occlusion (tMCAO) and in BV2 microglial cells exposed to oxygen-glucose deprivation or reoxygenation (OGD/R) treatment, respectively. In addition, we confirmed that autophagy was over-activated during CIRI by increased expression of autophagy activation related proteins with Beclin-1 and LC3B, while the expression of p62 was decreased. The degradation process of autophagy was inhibited, while the expression levels of LAMP-1 and Cathepsin-D were significantly reduced. Results of confocal laser microscopy and transmission electron microscopy (TEM) indicated that autophagy flux was disordered. In contrast, inhibition of TSPO prevented autophagy over-activation both in vivo and in vitro. Interestingly, suppression of TSPO alleviated nerve cell damage by reducing reactive oxygen species (ROS) and pro-inflammatory factors, including TNF-α and IL-6 in microglia cells. In summary, these results indicated that TSPO might affect CIRI by mediating autophagy dysfunction and thus might serve as a potential target for ischemic stroke treatment.
Collapse
Affiliation(s)
- Yusufu Mahemuti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China; School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, PR China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science & Brain-Machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, Zhejiang, PR China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, Zhejiang, PR China
| | - Kaheerman Kadeer
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Riqing Su
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Abudureheman Abula
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yirizhati Aili
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aierpati Maimaiti
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Subinuer Abulaiti
- Department of Epidemiology and Biostatistics, Institute of Public Health, Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | | | - Tong Miao
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Shihao Jiang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Aximujiang Axier
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Maimaitili Aisha
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Yongxin Wang
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China
| | - Xiaojiang Cheng
- Department of Neurosurgery, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, PR China.
| |
Collapse
|
5
|
Park J, Wasim S, Jung JH, Kim MH, Lee BC, Alam MM, Lee SY. Synthesis, In Silico and In Vitro Characterization of Novel N, N-Substituted Pyrazolopyrimidine Acetamide Derivatives for the 18KDa Translocator Protein (TSPO). Pharmaceuticals (Basel) 2023; 16:ph16040576. [PMID: 37111333 PMCID: PMC10142799 DOI: 10.3390/ph16040576] [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: 02/08/2023] [Revised: 04/01/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
The translocator protein (TSPO) is an interesting biological target for molecular imaging and therapy because the overexpression of TSPO is associated with microglial activation caused by neuronal damage or neuroinflammation, and these activated microglia are involved in various central nervous system (CNS) diseases. The TSPO is a target for neuroprotective treatment, which is used with the aim of reducing microglial cell activation. The novel N,N-disubstituted pyrazolopyrimidine acetamides scaffold (GMA 7-17), which bears a fluorine atom and is directly linked to the phenyl moiety, was synthesized, and each of the novel ligands was characterized in vitro. All of the newly synthesized ligands displayed picomolar to nanomolar affinity for the TSPO. Particularly, an in vitro affinity study led to the discovery of 2-(5,7-diethyl-2-(4-fluorophenyl)pyrazolo [1,5-a]pyrimidin-3-yl)-N-ethyl-N-phenylacetamide GMA 15 (Ki = 60 pM), a novel TSPO ligand that exhibits a 61-fold enhancement in affinity compared to the reference standard DPA-714 (Ki = 3.66 nM). Molecular dynamic (MD) studies of the highest affinity binder, GMA 15, were carried out to check its time-dependent stability with the receptor compared to DPA-714 and PK11195. The hydrogen bond plot also indicated that GMA 15 formed higher hydrogen bonds compared to DPA-714 and PK11195. We anticipate that further optimization to enhance the potency in a cellular assay needs to be followed, but our strategy of identifying potential TSPO binding novel scaffolds may open up a new avenue to develop novel TSPO ligands suited for potential molecular imaging and a wide range of therapeutic applications.
Collapse
Affiliation(s)
- Jaekyung Park
- Gachon Advanced Institute for Health Science and Technology, Graduate School, Gachon University, Incheon 21999, Republic of Korea
| | - Sobia Wasim
- Department of Biochemistry, College of Medicine, Gachon University, Incheon 21999, Republic of Korea
| | - Jae Ho Jung
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Mi-Hyun Kim
- Gachon Institute of Pharmaceutical Science and Department of Pharmacy, College of Pharmacy, Gachon University, Incheon 21936, Republic of Korea
| | - Byung Chul Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
- Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 16229, Republic of Korea
| | | | - Sang-Yoon Lee
- Gachon Advanced Institute for Health Science and Technology, Graduate School, Gachon University, Incheon 21999, Republic of Korea
- Neuroscience Research Institute, Gachon University, Incheon 20565, Republic of Korea
- Department of Neuroscience, College of Medicine, Gachon University, Incheon 21936, Republic of Korea
| |
Collapse
|
6
|
Aguado L, Joya A, Garbizu M, Plaza-García S, Iglesias L, Hernández MI, Ardaya M, Mocha N, Gómez-Vallejo V, Cossio U, Higuchi M, Rodríguez-Antigüedad A, Freijo MM, Domercq M, Matute C, Ramos-Cabrer P, Llop J, Martín A. Therapeutic effect of α7 nicotinic receptor activation after ischemic stroke in rats. J Cereb Blood Flow Metab 2023:271678X231161207. [PMID: 36916034 PMCID: PMC10369150 DOI: 10.1177/0271678x231161207] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
Nicotinic acetylcholine α7 receptors (α7 nAChRs) have a well-known modulator effect in neuroinflammation. Yet, the therapeutical effect of α7 nAChRs activation after stroke has been scarcely evaluated to date. The role of α7 nAChRs activation with PHA 568487 on inflammation after brain ischemia was assessed with positron emission tomography (PET) using [18F]DPA-714 and [18F]BR-351 radiotracers after transient middle cerebral artery occlusion (MCAO) in rats. The assessment of brain oedema, blood brain barrier (BBB) disruption and neurofunctional progression after treatment was evaluated with T2 weighted and dynamic contrast-enhanced magnetic resonance imaging (T2 W and DCE-MRI) and neurological evaluation. The activation of α7 nAChRs resulted in a decrease of ischemic lesion, midline displacement and cell neurodegeneration from days 3 to 7 after ischemia. Besides, the treatment with PHA 568487 improved the neurofunctional outcome. Treated ischemic rats showed a significant [18F]DPA-714-PET uptake reduction at day 7 together with a decrease of activated microglia/infiltrated macrophages. Likewise, the activation of α7 receptors displayed an increase of [18F]BR-351-PET signal in ischemic cortical regions, which resulted from the overactivation of MMP-2. Finally, the treatment with PHA 568487 showed a protective effect on BBB disruption and blood brain vessel integrity after cerebral ischemia.
Collapse
Affiliation(s)
- Laura Aguado
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Ana Joya
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | | | - Sandra Plaza-García
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Leyre Iglesias
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Neurovascular Group, Biocruces Health Research Institute, Barakaldo, Spain
| | | | - María Ardaya
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Donostia International Physics Center (DIPC), San Sebastian, Spain
| | - Naroa Mocha
- Achucarro Basque Center for Neuroscience, Leioa, Spain
| | | | - Unai Cossio
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Makoto Higuchi
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | | | - Mari Mar Freijo
- Neurovascular Group, Biocruces Health Research Institute, Barakaldo, Spain.,Department of Neurology, Cruces University Hospital, Barakaldo, Spain
| | - María Domercq
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of Basque Country (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of Basque Country (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Pedro Ramos-Cabrer
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
| | - Jordi Llop
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain.,Centro de Investigación Biomédica en Red - Enfermedades Respiratorias, CIBERES, Madrid, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
7
|
Wang Z, Song Y, Bai S, Xiang W, Zhou X, Han L, Zhu D, Guan Y. Imaging of microglia in post-stroke inflammation. Nucl Med Biol 2023; 118-119:108336. [PMID: 37028196 DOI: 10.1016/j.nucmedbio.2023.108336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023]
Abstract
Microglia constantly survey the central nervous system microenvironment and maintain brain homeostasis. Microglia activation, polarization and inflammatory response are of great importance in the pathophysiology of ischemic stroke. For exploring biochemical processes in vivo, positron emission tomography (PET) is a superior imaging tool. Translocator protein 18 kDa (TSPO), is a validated neuroinflammatory biomarker which is widely used to evaluate various central nervous system (CNS) pathologies in both preclinical and clinical studies. TSPO level can be elevated due to peripheral inflammatory cells infiltration and glial cells activation. Therefore, a clear understanding of the dynamic changes between microglia and TSPO is critical for interpreting PET studies and understanding the pathophysiology after ischemic stroke. Our review discusses alternative biological targets that have attracted considerable interest for the imaging of microglia activation in recent years, and the potential value of imaging of microglia in the assessment of stroke therapies.
Collapse
|
8
|
Rejc L, Gómez-Vallejo V, Joya A, Arsequell G, Egimendia A, Castellnou P, Ríos-Anglada X, Cossío U, Baz Z, Iglesias L, Capetillo-Zarate E, Ramos-Cabrer P, Martin A, Llop J. Longitudinal evaluation of neuroinflammation and oxidative stress in a mouse model of Alzheimer disease using positron emission tomography. Alzheimers Res Ther 2022; 14:80. [PMID: 35676734 PMCID: PMC9178858 DOI: 10.1186/s13195-022-01016-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/11/2022] [Indexed: 11/30/2022]
Abstract
Background Validation of new biomarkers of Alzheimer disease (AD) is crucial for the successful development and implementation of treatment strategies. Additional to traditional AT(N) biomarkers, neuroinflammation biomarkers, such as translocator protein (TSPO) and cystine/glutamine antiporter system (xc-), could be considered when assessing AD progression. Herein, we report the longitudinal investigation of [18F]DPA-714 and [18F]FSPG for their ability to detect TSPO and xc- biomarkers, respectively, in the 5xFAD mouse model for AD. Methods Expression of TSPO and xc- system was assessed longitudinally (2–12 months of age) on 5xFAD mice and their respective controls by positron emission tomography (PET) imaging using radioligands [18F]DPA-714 and [18F]FSPG. In parallel, in the same mice, amyloid-β plaque deposition was assessed with the amyloid PET radiotracer [18F]florbetaben. In vivo findings were correlated to ex vivo immunofluorescence staining of TSPO and xc- in microglia/macrophages and astrocytes on brain slices. Physiological changes of the brain tissue were assessed by magnetic resonance imaging (MRI) in 12-month-old mice. Results PET studies showed a significant increase in the uptake of [18F]DPA-714 and [18F]FSPG in the cortex, hippocampus, and thalamus in 5xFAD but not in WT mice over time. The results correlate with Aβ plaque deposition. Ex vivo staining confirmed higher TSPO overexpression in both, microglia/macrophages and astrocytes, and overexpression of xc- in non-glial cells of 5xFAD mice. Additionally, the results show that Aβ plaques were surrounded by microglia/macrophages overexpressing TSPO. MRI studies showed significant tissue shrinkage and microstructural alterations in 5xFAD mice compared to controls. Conclusions TSPO and xc- overexpression can be assessed by [18F]DPA-714 and [18F]FSPG, respectively, and correlate with the level of Aβ plaque deposition obtained with a PET amyloid tracer. These results position the two tracers as promising imaging tools for the evaluation of disease progression. Graphical abstract Longitudinal in vivo study in the 5xFAD mouse model shows that TSPO and oxidative stress assessment through [18F]DPA-714 and [18F]FSPG-PET imaging, respectively, could serve as a potential tool for the evaluation of Alzheimer disease progression. ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13195-022-01016-5.
Collapse
|
9
|
Viviano M, Barresi E, Siméon FG, Costa B, Taliani S, Da Settimo F, Pike VW, Castellano S. Essential Principles and Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging. Curr Med Chem 2022; 29:4862-4890. [PMID: 35352645 PMCID: PMC10080361 DOI: 10.2174/0929867329666220329204054] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 12/21/2021] [Accepted: 01/25/2022] [Indexed: 11/22/2022]
Abstract
The translocator protein 18kDa (TSPO) is expressed in the outer mitochondrial membrane and is implicated in several functions, including cholesterol transport and steroidogenesis. Under normal physiological conditions, TSPO is present in very low concentrations in the human brain but is markedly upregulated in response to brain injury and inflammation. This upregulation is strongly associated with activated microglia. Therefore, TSPO is particularly suited for assessing active gliosis associated with brain lesions following injury or disease. For over three decades, TSPO has been studied as a biomarker. Numerous radioligands for positron emission tomography (PET) that target TSPO have been developed for imaging inflammatory progression in the brain. Although [11C]PK11195, the prototypical first-generation PET radioligand, is still widely used for in vivo studies, mainly now as its single more potent R-enantiomer, it has severe limitations, including low sensitivity and poor amenability to quantification. Second-generation radioligands are characterized by higher TSPO specific signals but suffer from other drawbacks, such as sensitivity to the TSPO single nucleotide polymorphism (SNP) rs6971. Therefore, their applications in human studies have the burden of needing to genotype subjects. Consequently, recent efforts are focused on developing improved radioligands that combine the optimal features of the second generation with the ability to overcome the differences in binding affinities across the population. This review presents essential principles in the design and development of TSPO PET ligands and discusses prominent examples among the main chemotypes.
Collapse
Affiliation(s)
- Monica Viviano
- Department of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
| | | | - Fabrice G. Siméon
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126, Pisa, Italy
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126, Pisa, Italy
| | | | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sabrina Castellano
- Department of Pharmacy, University of Salerno, 84084 Fisciano (SA), Italy
| |
Collapse
|
10
|
Van Camp N, Lavisse S, Roost P, Gubinelli F, Hillmer A, Boutin H. TSPO imaging in animal models of brain diseases. Eur J Nucl Med Mol Imaging 2021; 49:77-109. [PMID: 34245328 PMCID: PMC8712305 DOI: 10.1007/s00259-021-05379-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/25/2021] [Indexed: 12/19/2022]
Abstract
Over the last 30 years, the 18-kDa TSPO protein has been considered as the PET imaging biomarker of reference to measure increased neuroinflammation. Generally assumed to image activated microglia, TSPO has also been detected in endothelial cells and activated astrocytes. Here, we provide an exhaustive overview of the recent literature on the TSPO-PET imaging (i) in the search and development of new TSPO tracers and (ii) in the understanding of acute and chronic neuroinflammation in animal models of neurological disorders. Generally, studies testing new TSPO radiotracers against the prototypic [11C]-R-PK11195 or more recent competitors use models of acute focal neuroinflammation (e.g. stroke or lipopolysaccharide injection). These studies have led to the development of over 60 new tracers during the last 15 years. These studies highlighted that interpretation of TSPO-PET is easier in acute models of focal lesions, whereas in chronic models with lower or diffuse microglial activation, such as models of Alzheimer's disease or Parkinson's disease, TSPO quantification for detection of neuroinflammation is more challenging, mirroring what is observed in clinic. Moreover, technical limitations of preclinical scanners provide a drawback when studying modest neuroinflammation in small brains (e.g. in mice). Overall, this review underlines the value of TSPO imaging to study the time course or response to treatment of neuroinflammation in acute or chronic models of diseases. As such, TSPO remains the gold standard biomarker reference for neuroinflammation, waiting for new radioligands for other, more specific targets for neuroinflammatory processes and/or immune cells to emerge.
Collapse
Affiliation(s)
- Nadja Van Camp
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Sonia Lavisse
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Pauline Roost
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Francesco Gubinelli
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, 92265, Fontenay-aux-Roses, France
| | - Ansel Hillmer
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
- Department of Radiology & Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale School of Engineering & Applied Science, New Haven, CT, USA
| | - Hervé Boutin
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Brain and Mental Health, University of Manchester, M13 9PL, Manchester, UK.
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, M20 3LJ, Manchester, UK.
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, UK.
| |
Collapse
|
11
|
Nutma E, Ceyzériat K, Amor S, Tsartsalis S, Millet P, Owen DR, Papadopoulos V, Tournier BB. Cellular sources of TSPO expression in healthy and diseased brain. Eur J Nucl Med Mol Imaging 2021; 49:146-163. [PMID: 33433698 PMCID: PMC8712293 DOI: 10.1007/s00259-020-05166-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/13/2020] [Indexed: 12/11/2022]
Abstract
The 18 kDa translocator protein (TSPO) is a highly conserved protein located in the outer mitochondrial membrane. TSPO binding, as measured with positron emission tomography (PET), is considered an in vivo marker of neuroinflammation. Indeed, TSPO expression is altered in neurodegenerative, neuroinflammatory, and neuropsychiatric diseases. In PET studies, the TSPO signal is often viewed as a marker of microglial cell activity. However, there is little evidence in support of a microglia-specific TSPO expression. This review describes the cellular sources and functions of TSPO in animal models of disease and human studies, in health, and in central nervous system diseases. A discussion of methods of analysis and of quantification of TSPO is also presented. Overall, it appears that the alterations of TSPO binding, their cellular underpinnings, and the functional significance of such alterations depend on many factors, notably the pathology or the animal model under study, the disease stage, and the involved brain regions. Thus, further studies are needed to fully determine how changes in TSPO binding occur at the cellular level with the ultimate goal of revealing potential therapeutic pathways.
Collapse
Affiliation(s)
- Erik Nutma
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
| | - Kelly Ceyzériat
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Division of Nuclear medicine and Molecular Imaging, University Hospitals of Geneva, Geneva, Switzerland
- Division of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, Geneva, Switzerland
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, VUmc, Amsterdam, The Netherlands
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and the London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Philippe Millet
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
| | - David R Owen
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Benjamin B Tournier
- Division of Adult Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Avenue de la Roseraie, 64, 1206, Geneva, Switzerland.
- Department of Psychiatry, University of Geneva, Geneva, Switzerland.
| |
Collapse
|
12
|
Yamasaki T, Hatori A, Zhang Y, Mori W, Kurihara Y, Ogawa M, Wakizaka H, Rong J, Wang L, Liang S, Zhang MR. Neuroprotective effects of minocycline and KML29, a potent inhibitor of monoacylglycerol lipase, in an experimental stroke model: a small-animal positron emission tomography study. Am J Cancer Res 2021; 11:9492-9502. [PMID: 34646382 PMCID: PMC8490517 DOI: 10.7150/thno.64320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/01/2021] [Indexed: 11/14/2022] Open
Abstract
Hypoxia caused by ischemia induces acidosis and neuroexcitotoxicity, resulting in neuronal death in the central nervous system (CNS). Monoacylglycerol lipase (MAGL) is a modulator of 2-arachidonoylglycerol (2-AG), which is involved in retrograde inhibition of glutamate release in the endocannabinoid system. In the present study, we used positron emission tomography (PET) to monitor MAGL-positive neurons and neuroinflammation in the brains of ischemic rats. Additionally, we performed PET imaging to evaluate the neuroprotective effects of an MAGL inhibitor in an ischemic injury model. Methods: Ischemic-injury rat models were induced by intraluminal right middle cerebral artery occlusion (MCAO). PET studies of the brains of the ischemic rats were performed at several experimental time points (pre-occlusion, days 2, 4, and 7 after the MCAO surgery) using [11C]SAR127303 for MAGL and [18F]FEBMP for 18 kDa translocator protein (TSPO, a hall-mark of neuroinflammation). Medication using minocycline (a well-known neuroprotective agent) or KML29 (a potent MAGL inhibitor) was given immediately after the MCAO surgery and then daily over the subsequent three days. Results: PET imaging of the ischemic rats using [11C]SAR127303 showed an acute decline of radioactive accumulation in the ipsilateral side at two days after MCAO surgery (ratio of the area under the curve between the ipsilateral and contralateral sides: 0.49 ± 0.04 in the cortex and 0.73 ± 0.02 in the striatum). PET imaging with [18F]FEBMP, however, showed a moderate increase in accumulation of radioactivity in the ipsilateral hemisphere on day 2 (1.36 ± 0.11), and further increases on day 4 (1.72 ± 0.15) and day 7 (1.99 ± 0.06). Treatment with minocycline or KML29 eased the decline in radioactive accumulation of [11C]SAR127303 for MAGL (minocycline-treated group: 0.82 ± 0.06 in the cortex and 0.81 ± 0.05 in the striatum; KML29-treated group: 0.72 ± 0.07 in the cortex and 0.88 ± 0.04 in the striatum) and increased uptake of [18F]FEBMP for TSPO (minocycline-treated group: 1.52 ± 0.21 in the cortex and 1.56 ± 0.11 in the striatum; KML29-treated group: 1.63 ± 0.09 in the cortex and 1.50 ± 0.17 in the striatum). In MCAO rats, minocycline treatment showed a neuroprotective effect in the sensorimotor cortex suffering from severe hypoxic injury, whereas KML29 treatment saved neurons in the striatum, including bundles of myelinated axons. Conclusions: PET imaging allowed visualization of the different neuroprotective effects of minocycline and KML29, and indicated that combination pharmacotherapy using these drugs may be an effective therapy in acute ischemia.
Collapse
|
13
|
Zhang L, Hu K, Shao T, Hou L, Zhang S, Ye W, Josephson L, Meyer JH, Zhang MR, Vasdev N, Wang J, Xu H, Wang L, Liang SH. Recent developments on PET radiotracers for TSPO and their applications in neuroimaging. Acta Pharm Sin B 2021; 11:373-393. [PMID: 33643818 PMCID: PMC7893127 DOI: 10.1016/j.apsb.2020.08.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
The 18 kDa translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is predominately localized to the outer mitochondrial membrane in steroidogenic cells. Brain TSPO expression is relatively low under physiological conditions, but is upregulated in response to glial cell activation. As the primary index of neuroinflammation, TSPO is implicated in the pathogenesis and progression of numerous neuropsychiatric disorders and neurodegenerative diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), multiple sclerosis (MS), major depressive disorder (MDD) and obsessive compulsive disorder (OCD). In this context, numerous TSPO-targeted positron emission tomography (PET) tracers have been developed. Among them, several radioligands have advanced to clinical research studies. In this review, we will overview the recent development of TSPO PET tracers, focusing on the radioligand design, radioisotope labeling, pharmacokinetics, and PET imaging evaluation. Additionally, we will consider current limitations, as well as translational potential for future application of TSPO radiopharmaceuticals. This review aims to not only present the challenges in current TSPO PET imaging, but to also provide a new perspective on TSPO targeted PET tracer discovery efforts. Addressing these challenges will facilitate the translation of TSPO in clinical studies of neuroinflammation associated with central nervous system diseases.
Collapse
Key Words
- AD, Alzheimer's disease
- ALS, amyotrophic lateral sclerosis
- AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid
- ANT, adenine nucleotide transporter
- Am, molar activities
- BBB, blood‒brain barrier
- BMSC, bone marrow stromal cells
- BP, binding potential
- BPND, non-displaceable binding potential
- BcTSPO, Bacillus cereus TSPO
- CBD, corticobasal degeneration
- CNS disorders
- CNS, central nervous system
- CRAC, cholesterol recognition amino acid consensus sequence
- DLB, Lewy body dementias
- EP, epilepsy
- FTD, frontotemporal dementia
- HAB, high-affinity binding
- HD, Huntington's disease
- HSE, herpes simplex encephalitis
- IMM, inner mitochondrial membrane
- KA, kainic acid
- LAB, low-affinity binding
- LPS, lipopolysaccharide
- MAB, mixed-affinity binding
- MAO-B, monoamine oxidase B
- MCI, mild cognitive impairment
- MDD, major depressive disorder
- MMSE, mini-mental state examination
- MRI, magnetic resonance imaging
- MS, multiple sclerosis
- MSA, multiple system atrophy
- Microglial activation
- NAA/Cr, N-acetylaspartate/creatine
- Neuroinflammation
- OCD, obsessive compulsive disorder
- OMM, outer mitochondrial membrane
- P2X7R, purinergic receptor P2X7
- PAP7, RIa-associated protein
- PBR, peripheral benzodiazepine receptor
- PCA, posterior cortical atrophy
- PD, Parkinson's disease
- PDD, PD dementia
- PET, positron emission tomography
- PKA, protein kinase A
- PRAX-1, PBR-associated protein 1
- PSP, progressive supranuclear palsy
- Positron emission tomography (PET)
- PpIX, protoporphyrin IX
- QA, quinolinic acid
- RCYs, radiochemical yields
- ROS, reactive oxygen species
- RRMS, relapsing remitting multiple sclerosis
- SA, specific activity
- SAH, subarachnoid hemorrhage
- SAR, structure–activity relationship
- SCIDY, spirocyclic iodonium ylide
- SNL, selective neuronal loss
- SNR, signal to noise ratio
- SUV, standard uptake volume
- SUVR, standard uptake volume ratio
- TBAH, tetrabutyl ammonium hydroxide
- TBI, traumatic brain injury
- TLE, temporal lobe epilepsy
- TSPO
- TSPO, translocator protein
- VDAC, voltage-dependent anion channel
- VT, distribution volume
- d.c. RCYs, decay-corrected radiochemical yields
- dMCAO, distal middle cerebral artery occlusion
- fP, plasma free fraction
- n.d.c. RCYs, non-decay-corrected radiochemical yields
- p.i., post-injection
Collapse
|
14
|
Joya A, Martín A. Evaluation of glial cell proliferation with non-invasive molecular imaging methods after stroke. Neural Regen Res 2021; 16:2209-2210. [PMID: 33818496 PMCID: PMC8354125 DOI: 10.4103/1673-5374.310681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Ana Joya
- Achucarro Basque Center for Neuroscience, Leioa; CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, Leioa; Ikerbasque Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
15
|
Ardaya M, Joya A, Padro D, Plaza-García S, Gómez-Vallejo V, Sánchez M, Garbizu M, Cossío U, Matute C, Cavaliere F, Llop J, Martín A. In vivo PET Imaging of Gliogenesis After Cerebral Ischemia in Rats. Front Neurosci 2020; 14:793. [PMID: 32848565 PMCID: PMC7406641 DOI: 10.3389/fnins.2020.00793] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/06/2020] [Indexed: 11/13/2022] Open
Abstract
In vivo positron emission tomography of neuroinflammation has mainly focused on the evaluation of glial cell activation using radiolabeled ligands. However, the non-invasive imaging of neuroinflammatory cell proliferation has been scarcely evaluated so far. In vivo and ex vivo assessment of gliogenesis after transient middle cerebral artery occlusion (MCAO) in rats was carried out using PET imaging with the marker of cell proliferation 3′-Deoxy-3′-[18F] fluorothymidine ([18F]FLT), magnetic resonance imaging (MRI) and fluorescence immunohistochemistry. MRI-T2W studies showed the presence of the brain infarction at 24 h after MCAO affecting cerebral cortex and striatum. In vivo PET imaging showed a significant increase in [18F]FLT uptake in the ischemic territory at day 7 followed by a progressive decline from day 14 to day 28 after ischemia onset. In addition, immunohistochemistry studies using Ki67, CD11b, and GFAP to evaluate proliferation of microglia and astrocytes confirmed the PET findings showing the increase of glial proliferation at day 7 after ischemia followed by decrease later on. Hence, these results show that [18F]FLT provides accurate quantitative information on the time course of glial proliferation in experimental stroke. Finally, this novel brain imaging method might guide on the imaging evaluation of the role of gliogenesis after stroke.
Collapse
Affiliation(s)
- María Ardaya
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of Basque Country (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Ana Joya
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Daniel Padro
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Sandra Plaza-García
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | | | | | | | - Unai Cossío
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of Basque Country (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Fabio Cavaliere
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of Basque Country (UPV/EHU) and CIBERNED, Leioa, Spain
| | - Jordi Llop
- CIC biomaGUNE, Basque Research and Technology Alliance, San Sebastian, Spain.,Centro de Investigación Biomédica en Red - Enfermedades Respiratorias, CIBERES, Madrid, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
16
|
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.
Collapse
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.)
| |
Collapse
|
17
|
Substrate Reduction Therapy for Sandhoff Disease through Inhibition of Glucosylceramide Synthase Activity. Mol Ther 2019; 27:1495-1506. [PMID: 31208914 DOI: 10.1016/j.ymthe.2019.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/10/2019] [Accepted: 05/19/2019] [Indexed: 12/12/2022] Open
Abstract
Neuronopathic glycosphingolipidoses are a sub-group of lysosomal storage disorders for which there are presently no effective therapies. Here, we evaluated the potential of substrate reduction therapy (SRT) using an inhibitor of glucosylceramide synthase (GCS) to decrease the synthesis of glucosylceramide (GL1) and related glycosphingolipids. The substrates that accumulate in Sandhoff disease (e.g., ganglioside GM2 and its nonacylated derivative, lyso-GM2) are distal to the drug target, GCS. Treatment of Sandhoff mice with a GCS inhibitor that has demonstrated CNS access (Genz-682452) reduced the accumulation of GL1 and GM2, as well as a variety of disease-associated substrates in the liver and brain. Concomitant with these effects was a significant decrease in the expression of CD68 and glycoprotein non-metastatic melanoma B protein (Gpnmb) in the brain, indicating a reduction in microgliosis in the treated mice. Moreover, using in vivo imaging, we showed that the monocytic biomarker translocator protein (TSPO), which was elevated in Sandhoff mice, was normalized following Genz-682452 treatment. These positive effects translated in turn into a delay (∼28 days) in loss of motor function and coordination, as measured by rotarod latency, and a significant increase in longevity (∼17.5%). Together, these results support the development of SRT for the treatment of gangliosidoses, particularly in patients with residual enzyme activity.
Collapse
|
18
|
Betlazar C, Harrison-Brown M, Middleton RJ, Banati R, Liu GJ. Cellular Sources and Regional Variations in the Expression of the Neuroinflammatory Marker Translocator Protein (TSPO) in the Normal Brain. Int J Mol Sci 2018; 19:ijms19092707. [PMID: 30208620 PMCID: PMC6163555 DOI: 10.3390/ijms19092707] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/09/2018] [Accepted: 09/09/2018] [Indexed: 02/07/2023] Open
Abstract
The inducible expression of the mitochondrial translocator protein 18 kDa (TSPO) by activated microglia is a prominent, regular feature of acute and chronic-progressive brain pathology. This expression is also the rationale for the continual development of new TSPO binding molecules for the diagnosis of "neuroinflammation" by molecular imaging. However, there is in the normal brain an ill-defined, low-level constitutive expression of TSPO. Taking advantage of healthy TSPO knockout mouse brain tissue to validate TSPO antibody specificity, this study uses immunohistochemistry to determine the regional distribution and cellular sources of TSPO in the normal mouse brain. Fluorescence microscopy revealed punctate TSPO immunostaining in vascular endothelial cells throughout the brain. In the olfactory nerve layers and glomeruli of the olfactory bulb, choroid plexus and ependymal layers, we confirm constitutive TSPO expression levels similar to peripheral organs, while some low TSPO expression is present in regions of known neurogenesis, as well as cerebellar Purkinje cells. The distributed-sparse expression of TSPO in endothelial mitochondria throughout the normal brain can be expected to give rise to a low baseline signal in TSPO molecular imaging studies. Finally, our study emphasises the need for valid and methodologically robust verification of the selectivity of TSPO ligands through the use of TSPO knockout tissues.
Collapse
Affiliation(s)
- Calina Betlazar
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Meredith Harrison-Brown
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Ryan J Middleton
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
| | - Richard Banati
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Guo-Jun Liu
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia.
- Discipline of Medical Imaging & Radiation Sciences, Faculty of Medicine and Health, Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW 2050, Australia.
| |
Collapse
|
19
|
Miyajima N, Ito M, Rokugawa T, Iimori H, Momosaki S, Omachi S, Shimosegawa E, Hatazawa J, Abe K. Detection of neuroinflammation before selective neuronal loss appearance after mild focal ischemia using [ 18F]DPA-714 imaging. EJNMMI Res 2018; 8:43. [PMID: 29884977 PMCID: PMC5993708 DOI: 10.1186/s13550-018-0400-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/23/2018] [Indexed: 12/13/2022] Open
Abstract
Background Translocator protein (TSPO) imaging can be used to detect neuroinflammation (including microglial activation) after acute cerebral infarction. However, longitudinal changes of TSPO binding after mild ischemia that induces selective neuronal loss (SNL) without acute infarction are not well understood. Here, we performed TSPO imaging with [18F]DPA-714 to determine the time course of neuroinflammation and SNL after mild focal ischemia. Results Mild focal ischemia was induced by middle cerebral artery occlusion (MCAO) for 20 min. In MCAO rats without acute infarction investigated by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining, in vitro ARG revealed a significant increase of [18F]DPA-714 binding in the ipsilateral striatum compared with that in the contralateral side at 1, 2, 3, and 7 days after MCAO. Increased [18F]DPA-714 binding was observed in the cerebral cortex penumbra, reaching maximal values at 7 days after MCAO. Activation of striatal microglia and astrocytes was observed with immunohistochemistry of ionized calcium binding adaptor molecule 1 (Iba1) and glial fibrillary acidic protein (GFAP) at 2, 3, and 7 days after MCAO. SNL was investigated with Nissl staining and neuronal nuclei (NeuN) immunostaining and observed in the ischemic core region of the striatum on days 3 and 7 after MCAO. We confirmed that total distribution volume of [18F]DPA-714 in the ipsilateral striatum was significantly increased at 2 and 7 days after MCAO using positron emission tomography (PET). Conclusions [18F]DPA-714 binding measured with in vitro ARG was increased before SNL appeared, and this change was detected by in vivo PET. These findings suggest that TSPO PET imaging might be useful for detection of neuroinflammation leading to SNL after focal ischemia.
Collapse
Affiliation(s)
- Natsumi Miyajima
- Translational Research Unit, Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, 5610825, Japan.
| | - Miwa Ito
- Translational Research Unit, Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, 5610825, Japan
| | - Takemi Rokugawa
- Translational Research Unit, Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, 5610825, Japan
| | - Hitoshi Iimori
- Department of Applied Chemistry and Analysis, Research Laboratory for Development, Shionogi & Co., Ltd., Osaka, Japan
| | - Sotaro Momosaki
- Translational Research Unit, Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, 5610825, Japan
| | - Shigeki Omachi
- Department of medical affairs, Shionogi & Co., Ltd., Osaka, Japan
| | - Eku Shimosegawa
- Department of Molecular Imaging in Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.,Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan.,PET Molecular Imaging Center, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun Hatazawa
- Department of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan.,PET Molecular Imaging Center, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kohji Abe
- Translational Research Unit, Biomarker R&D Department, Shionogi & Co., Ltd., Osaka, 5610825, Japan
| |
Collapse
|